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+The Project Gutenberg EBook of Encyclopaedia Britannica, 11th Edition,
+Volume 8, Slice 9, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 9
+       "Dyer" to "Echidna"
+
+Author: Various
+
+Release Date: January 8, 2011 [EBook #34878]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ENCYCLOPAEDIA BRITANNICA ***
+
+
+
+
+Produced by Marius Masi, Don Kretz and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+
+
+
+Transcriber's notes:
+
+(1) Numbers following letters (without space) like C2 were originally
+      printed in subscript. Letter subscripts are preceded by an
+      underscore, like C_n.
+
+(2) Characters following a carat (^) were printed in superscript.
+
+(3) Side-notes were relocated to function as titles of their respective
+      paragraphs.
+
+(4) Macrons and breves above letters and dots below letters were not
+      inserted.
+
+(5) dP stands for the partial-derivative symbol, or curled 'd'.
+
+(6) [oo] stands for the infinity symbol, and [int] for the integral
+      symbol.
+
+(7) Letters followed with a grave accent "`" have originally dots above.
+
+(8) The following typographical errors have been corrected:
+
+    ARTICLE DYER, JOHN: "His poems were collected by Dodsley in 1770,
+      and by Mr Edward Thomas in 1903 for the Welsh Library, vol. iv."
+      'poems' amended from 'peoms'.
+
+    ARTICLE EAR: "The membranous semicircular canals are very much
+      smaller in section than the bony; in the ampulla of each is a
+      ridge..." 'the' amended from 'tbe'.
+
+    ARTICLE EARTH, FIGURE OF THE: "O. Callandreau, 'Mémoire sur la
+      théorie de la figure des planètes,' Ann. obs. de Paris (1889);..."
+      'Callandreau' amended from 'Callendreau'.
+
+    ARTICLE EATON, THEOPHILUS: "In October 1639 a form of government
+      was adopted, based on the Mosaic Law, and Eaton was elected
+      governor..." 'Mosaic' amended from 'Mosiac'.
+
+    ARTICLE ECCLESIASTES: "A particular instance is mentioned (ix.
+      13-15) of a beleaguered city saved by a wise man; but the man
+      happened to be poor, and no one remembered him." 'beleaguered'
+      amended from 'beleagured'.
+
+    ARTICLE ECCLESIASTES: "Such assertions as those of ii. 26 (God
+      gives joy to him who pleases him, and makes the sinner toil to lay
+      up for the latter),..." 'and' amended from 'amd'.
+
+    ARTICLE ECCLESIASTES: "This disagreement comes largely from the
+      attempts made to find definitely expressed Greek philosophical
+      dogmas in the book; such formulas it has not, but the general air
+      of Greek reflection seems unmistakable. The scepticism of Koheleth
+      differs from that of Job in quality and scope..." 'the' originally
+      repeated twice.
+
+    ARTICLE ECCLESIASTICAL JURISDICTION: "In the first case, they may
+      be punished by the ordinary of the place, acting as delegate of the
+      pope without special appointment (Conc. Trid. Sess. vi. c. 3)."
+      'special' amended from 'speical'.
+
+
+
+
+          ENCYCLOPAEDIA BRITANNICA
+
+  A DICTIONARY OF ARTS, SCIENCES, LITERATURE
+           AND GENERAL INFORMATION
+
+              ELEVENTH EDITION
+
+
+           VOLUME VIII, SLICE IX
+
+              Dyer to Echidna
+
+
+
+
+ARTICLES IN THIS SLICE:
+
+
+  DYER, SIR EDWARD              EAST LIVERPOOL
+  DYER, JOHN                    EAST LONDON
+  DYER, THOMAS HENRY            EASTON
+  DYMOKE                        EAST ORANGE
+  DYNAMICS                      EASTPORT
+  DYNAMITE                      EAST PROVIDENCE
+  DYNAMO                        EAST PRUSSIA
+  DYNAMOMETER                   EASTWICK, EDWARD BACKHOUSE
+  DYNASTY                       EATON, DORMAN BRIDGMAN
+  DYSART                        EATON, MARGARET O'NEILL
+  DYSENTERY                     EATON, THEOPHILUS
+  DYSPEPSIA                     EATON, WILLIAM
+  DYSTELEOLOGY                  EATON, WYATT
+  DZUNGARIA                     EAU CLAIRE
+  E                             EAU DE COLOGNE
+  EA                            EAUX-BONNES
+  EABANI                        EAVES
+  EACHARD, JOHN                 EAVESDRIP
+  EADBALD                       EBBW VALE
+  EADIE, JOHN                   EBEL, HERMANN WILHELM
+  EADMER                        EBEL, JOHANN GOTTFRIED
+  EADS, JAMES BUCHANAN          EBER, PAUL
+  EAGLE                         EBERBACH (town of Germany)
+  EAGLEHAWK                     EBERBACH (monastery of Germany)
+  EAGRE                         EBERHARD
+  EAKINS, THOMAS                EBERHARD, CHRISTIAN AUGUST GOTTLOB
+  EALING                        EBERHARD, JOHANN AUGUSTUS
+  EAR                           EBERLIN, JOHANN ERNST
+  EARL                          EBERS, GEORG MORITZ
+  EARLE, JOHN                   EBERSWALDE
+  EARLE, RALPH                  EBERT, FRIEDRICH ADOLF
+  EARL MARSHAL                  EBINGEN
+  EARLOM, RICHARD               EBIONITES
+  EARLSTON                      EBNER-ESCHENBACH, MARIE
+  EARLY, JUBAL ANDERSON         EBOLI
+  EARLY ENGLISH PERIOD          EBONY
+  EARN                          EBRARD, JOHANNES HEINRICH AUGUST
+  EARNEST                       EBRO
+  EAR-RING                      EBROÏN
+  EARTH                         EBURACUM
+  EARTH, FIGURE OF THE          EÇA DE QUEIROZ, JOSÉ MARIA
+  EARTH CURRENTS                ÉCARTÉ
+  EARTH-NUT                     ECBATANA
+  EARTH PILLAR                  ECCARD, JOHANN
+  EARTHQUAKE                    ECCELINO DA ROMANO
+  EARTH-STAR                    ECCENTRIC
+  EARTHWORM                     ECCHELLENSIS, ABRAHAM
+  EARWIG                        ECCLES
+  EASEMENT                      ECCLESFIELD
+  EAST, ALFRED                  ECCLESHALL
+  EAST ANGLIA                   ECCLESIA
+  EASTBOURNE                    ECCLESIASTES
+  EAST CHICAGO                  ECCLESIASTICAL COMMISSIONERS
+  EASTER                        ECCLESIASTICAL JURISDICTION
+  EASTER ISLAND                 ECCLESIASTICAL LAW
+  EASTERN BENGAL AND ASSAM      ECCLESIASTICUS
+  EASTERN QUESTION, THE         ECGBERT (king of the West Saxons)
+  EAST GRINSTEAD                ECGBERT (archbishop of York)
+  EAST HAM                      ECGFRITH
+  EASTHAMPTON                   ECGONINE
+  EAST HAMPTON                  ECHEGARAY Y EIZAGUIRRE, JOSÉ
+  EAST INDIA COMPANY            ÉCHELON
+  EAST INDIES                   ECHIDNA
+  EASTLAKE, SIR CHARLES LOCK
+
+
+
+
+DYER, SIR EDWARD (d. 1607), English courtier and poet, son of Sir Thomas
+Dyer, Kt., was born at Sharpham Park, Somersetshire. He was educated,
+according to Anthony à Wood, either at Balliol College or at Broadgates
+Hall, Oxford. He left the university without taking a degree, and after
+some time spent abroad appeared at Queen Elizabeth's court. His first
+patron was the earl of Leicester, who seems to have thought of putting
+him forward as a rival to Sir Christopher Hatton in the queen's favour.
+He is mentioned by Gabriel Harvey with Sidney as one of the ornaments of
+the court. Sidney in his will desired that his books should be divided
+between Fulke Greville (Lord Brooke) and Dyer. He was employed by
+Elizabeth on a mission (1584) to the Low Countries, and in 1589 was sent
+to Denmark. In a commission to inquire into manors unjustly alienated
+from the crown in the west country he did not altogether please the
+queen, but he received a grant of some forfeited lands in Somerset in
+1588. He was knighted and made chancellor of the order of the Garter in
+1596. William Oldys says of him that he "would not stoop to fawn," and
+some of his verses seem to show that the exigencies of life at court
+oppressed him. He was buried at St Saviour's, Southwark, on the 11th of
+May 1607. Wood says that many esteemed him to be a Rosicrucian, and that
+he was a firm believer in alchemy. He had a great reputation as a poet
+among his contemporaries, but very little of his work has survived.
+Puttenham in the _Arte of English Poesie_ speaks of "Maister Edward
+Dyar, for Elegie most sweete, solempne, and of high conceit." One of the
+poems universally accepted as his is "My Mynde to me a kingdome is."
+Among the poems in _England's Helicon_ (1600), signed S.E.D., and
+included in Dr A.B. Grosart's collection of Dyer's works (_Miscellanies
+of the Fuller Worthies Library_, vol. iv., 1876) is the charming
+pastoral "My Phillis hath the morninge sunne," but this comes from the
+_Phillis_ of Thomas Lodge. Grosart also prints a prose tract entitled
+_The Prayse of Nothing_ (1585). The _Sixe Idillia_ from Theocritus,
+reckoned by J.P. Collier among Dyer's works, were dedicated to, not
+written by, him.
+
+
+
+
+DYER, JOHN (c. 1700-1758), British poet, the son of a solicitor, was
+born in 1699 or 1700 at Aberglasney, in Carmarthenshire. He was sent to
+Westminster school and was destined for the law, but on his father's
+death he began to study painting. He wandered about South Wales,
+sketching and occasionally painting portraits. In 1726 his first poem,
+_Grongar Hill_, appeared in a miscellany published by Richard Savage,
+the poet. It was an irregular ode in the so-called Pindaric style, but
+Dyer entirely rewrote it into a loose measure of four cadences, and
+printed it separately in 1727. It had an immediate and brilliant
+success. _Grongar Hill_, as it now stands, is a short poem of only 150
+lines, describing in language of much freshness and picturesque charm
+the view from a hill overlooking the poet's native vale of Towy. A visit
+to Italy bore fruit in _The Ruins of Rome_ (1740), a descriptive piece
+in about 600 lines of Miltonic blank verse. He was ordained priest in
+1741, and held successively the livings of Calthorp in Leicestershire,
+Belchford (1751), Coningsby (1752), and Kirby-on-Bane (1756), the last
+three being Lincolnshire parishes. He married, in 1741, a Miss Ensor,
+said to be descended from the brother of Shakespeare. In 1757 he
+published his longest work, the didactic blank-verse epic of _The
+Fleece_, in four books, discoursing of the tending of sheep, of the
+shearing and preparation of the wool, of weaving, and of trade in
+woollen manufactures. The town took no interest in it, and Dodsley
+facetiously prophesied that "Mr Dyer would be buried in woollen." He
+died at Coningsby of consumption, on the 15th of December 1758.
+
+  His poems were collected by Dodsley in 1770, and by Mr Edward Thomas
+  in 1903 for the _Welsh Library_, vol. iv.
+
+
+
+
+DYER, THOMAS HENRY (1804-1888), English historical and antiquarian
+writer, was born in London on the 4th of May 1804. He was originally
+intended for a business career, and for some time acted as clerk in a
+West India house; but finding his services no longer required after the
+passing of the Negro Emancipation Act, he decided to devote himself to
+literature. In 1850 he published the _Life of Calvin_, a conscientious
+and on the whole impartial work, though the character of Calvin is
+somewhat harshly drawn, and his influence in the religious world
+generally is insufficiently appreciated. Dyer's first historical work
+was the _History of Modern Europe_ (1861-1864; 3rd ed. revised and
+continued to the end of the 19th century, by A. Hassall, 1901), a
+meritorious compilation and storehouse of facts, but not very readable.
+The _History of the City of Rome_ (1865) down to the end of the middle
+ages was followed by the _History of the Kings of Rome_ (1868), which,
+upholding against the German school the general credibility of the
+account of early Roman history, given in Livy and other classical
+authors, was violently attacked by J.R. Seeley and the _Saturday
+Review_, as showing ignorance of the comparative method. More favourable
+opinions of the work were expressed by others, but it is generally
+agreed that the author's scholarship is defective and that his views are
+far too conservative. _Roma Regalis_ (1872) and _A Plea for Livy_ (1873)
+were written in reply to his critics. Dyer frequently visited Greece and
+Italy, and his topographical works are probably his best; amongst these
+mention may be made of _Pompeii, its History, Buildings and Antiquities_
+(1867, new ed. in Bohn's _Illustrated Library_), and _Ancient Athens,
+its History, Topography and Remains_ (1873). His last publication was
+_On Imitative Art_ (1882). He died at Bath on the 30th of January 1888.
+
+
+
+
+DYMOKE, the name of an English family holding the office of king's
+champion. The functions of the champion were to ride into Westminster
+Hall at the coronation banquet, and challenge all comers to impugn the
+king's title (see CHAMPION). The earliest record of the ceremony at the
+coronation of an English king dates from the accession of Richard II. On
+this occasion the champion was Sir John Dymoke (d. 1381), who held the
+manor of Scrivelsby, Lincolnshire, in right of his wife Margaret,
+granddaughter of Joan Ludlow, who was the daughter and co-heiress of
+Philip Marmion, last Baron Marmion. The Marmions claimed descent from
+the lords of Fontenay, hereditary champions of the dukes of Normandy,
+and held the castle of Tamworth, Leicestershire, and the manor of
+Scrivelsby, Lincolnshire. The right to the championship was disputed
+with the Dymoke family by Sir Baldwin de Freville, lord of Tamworth, who
+was descended from an elder daughter of Philip Marmion. The court of
+claims eventually decided in favour of the owners of Scrivelsby on the
+ground that Scrivelsby was held in grand serjeanty, that is, that its
+tenure was dependent on rendering a special service, in this case the
+championship.
+
+Sir Thomas Dymoke (1428?-1471) joined a Lancastrian rising in 1469, and,
+with his brother-in-law Richard, Lord Willoughby and Welles, was
+beheaded in 1471 by order of Edward IV. after he had been induced to
+leave sanctuary on a promise of personal safety. The estates were
+restored to his son Sir Robert Dymoke (d. 1546), champion at the
+coronations of Richard III., Henry VII. and Henry VIII., who
+distinguished himself at the siege of Tournai and became treasurer of
+the kingdom. His descendants acted as champions at successive
+coronations. Lewis Dymoke (d. 1820) put in an unsuccessful claim before
+the House of Lords for the barony of Marmion. His nephew Henry
+(1801-1865) was champion at the coronation of George IV. He was
+accompanied on that occasion by the duke of Wellington and Lord Howard
+of Effingham. Henry Dymoke was created a baronet; he was succeeded by
+his brother John, rector of Scrivelsby (1804-1873), whose son Henry
+Lionel died without issue in 1875, when the baronetcy became extinct,
+the estate passing to a collateral branch of the family. After the
+coronation of George IV. the ceremony was allowed to lapse, but at the
+coronation of King Edward VII. H.S. Dymoke bore the standard of England
+in Westminster Abbey.
+
+
+
+
+DYNAMICS (from Gr. [Greek: dynamis], strength), the name of a branch of
+the science of Mechanics (q.v.). The term was at one time restricted to
+the treatment of motion as affected by force, being thus opposed to
+Statics, which investigated equilibrium or conditions of rest. In more
+recent times the word has been applied comprehensively to the action of
+force on bodies either at rest or in motion, thus including "dynamics"
+(now termed kinetics) in the restricted sense and "statics."
+
+ANALYTICAL DYNAMICS.--The fundamental principles of dynamics, and their
+application to special problems, are explained in the articles MECHANICS
+and MOTION, LAWS OF, where brief indications are also given of the more
+general methods of investigating the properties of a dynamical system,
+independently of the accidents of its particular constitution, which
+were inaugurated by J.L. Lagrange. These methods, in addition to the
+unity and breadth which they have introduced into the treatment of pure
+dynamics, have a peculiar interest in relation to modern physical
+speculation, which finds itself confronted in various directions with
+the problem of explaining on dynamical principles the properties of
+systems whose ultimate mechanism can at present only be vaguely
+conjectured. In determining the properties of such systems the methods
+of analytical geometry and of the infinitesimal calculus (or, more
+generally, of mathematical analysis) are necessarily employed; for this
+reason the subject has been named Analytical Dynamics. The following
+article is devoted to an outline of such portions of general dynamical
+theory as seem to be most important from the physical point of view.
+
+
+  1. _General Equations of Impulsive Motion._
+
+  The systems contemplated by Lagrange are composed of discrete
+  particles, or of rigid bodies, in finite number, connected (it may be)
+  in various ways by invariable geometrical relations, the fundamental
+  postulate being that the position of every particle of the system at
+  any time can be completely specified by means of the instantaneous
+  values of a finite number of independent variables q1, q2, ... q_n,
+  each of which admits of continuous variation over a certain range, so
+  that if x, y, z be the Cartesian co-ordinates of any one particle, we
+  have for example
+
+    x = [f](q1, q2, ... q_n), y = &c., z = &c.,   (1)
+
+  where the functions [f] differ (of course) from particle to particle.
+  In modern language, the variables q1, q2, ... q_n are _generalized
+  co-ordinates_ serving to specify the _configuration_ of the system;
+  their derivatives with respect to the time are denoted by q`1, q`2,
+  ... q`_n, and are called the _generalized components of velocity_. The
+  continuous sequence of configurations assumed by the system in any
+  actual or imagined motion (subject to the given connexions) is called
+  the _path_.
+
+
+    Impulsive motion.
+
+  For the purposes of a connected outline of the whole subject it is
+  convenient to deviate somewhat from the historical order of
+  development, and to begin with the consideration of _impulsive_
+  motion. Whatever the actual motion of the system at any instant, we
+  may conceive it to be generated instantaneously from rest by the
+  application of proper impulses. On this view we have, if x, y, z be
+  the rectangular co-ordinates of any particle m,
+
+    mx` = X', my` = Y', mz` = Z',   (2)
+
+  where X', Y', Z' are the components of the impulse on m. Now let
+  [delta]x, [delta]y, [delta]z be any infinitesimal variations of x, y,
+  z which are consistent with the connexions of the system, and let us
+  form the equation
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+       [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z),   (3)
+
+  where the sign [Sigma] indicates (as throughout this article) a
+  summation extending over all the particles of the system. To transform
+  (3) into an equation involving the variations [delta]q1, [delta]q2,
+  ... of the generalized co-ordinates, we have
+
+          dPx        dPx
+    x` = ---- q`1 + ---- q`2 + ..., &c., &c.   (4)
+         dPq1       dPq2
+
+               dPx              dPx
+    [delta]x = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.   (5)
+               dPq1             dPq2
+
+  and therefore
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+        (A11q`1 + A12q`2 + ...)[delta]q1 +
+        (A21q`1 + A22q`2 + ...)[delta]q2 + ...,   (6)
+
+  where
+                     _                                 _
+                    |  / dPx \²    / dPy \²    / dPz \² |               \
+    A_rr = [Sigma]m | ( ----- ) + ( ----- ) + ( ----- ) |,               |
+                    |_ \dPq_r/     \dPq_r/     \dPq_r/ _|                |
+                     _                                        _           > (7)
+                    |  dPx   dPx     dPy   dPy     dPz   dPz   |         |
+    A_rs = [Sigma]m | ----- ----- + ----- ----- + ----- -----  | = A_sr. |
+                    |_dPq_r dPq_s   dPq_r dPq_s   dPq_r dPq_s _|        /
+
+  If we form the expression for the kinetic energy [Tau] of the system,
+  we find
+
+    2[Tau] = [Sigma]m(x`² + y`² + z`²) = A11q`1² + A22q`2² + ...
+       + 2A12q`1q`2 + ... (8)
+
+  The coefficients A11, A22, ... A12, ... are by an obvious analogy
+  called the _coefficients of inertia_ of the system; they are in
+  general functions of the co-ordinates q1, q2, ... . The equation (6)
+  may now be written
+
+                                                     dP[Tau]             dP[Tau]
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = ------- [delta]q1 + ------- [delta]q2 + ... (9)
+                                                      dPq`1               dPq`2
+
+  This maybe regarded as the cardinal formula in Lagrange's method. For
+  the right-hand side of (3) we may write
+
+    [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z) = Q'1[delta]q1 + Q'2[delta]q2 + ... ,  (10)
+
+  where
+
+                   /   dPx       dPy       dPz \
+    Q'_r = [Sigma]( X'----- + Y'----- + Z'----- ).  (11)
+                   \  dPq_r     dPq_r     dPq_r/
+
+  The quantities Q1, Q2, ... are called the _generalized components of
+  impulse_. Comparing (9) and (10), we have, since the variations
+  [delta]q1, [delta]q2,... are independent,
+
+    dP[Tau]        dP[Tau]
+    ------- = Q'1, ------- = Q'2, ...  (12)
+     dPq`1          dPq`2
+
+  These are the general equations of impulsive motion. It is now usual
+  to write
+
+          dP[Tau]
+    p_r = -------   (13)
+          dPq`_r
+
+  The quantities p1, p2, ... represent the effects of the several
+  component impulses on the system, and are therefore called the
+  _generalized components of momentum_. In terms of them we have
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = p1[delta]q1 + p2[delta]q2 + ...  (14)
+
+  Also, since [Tau] is a homogeneous quadratic function of the
+  velocities q`1, q`2 ...,
+
+    2[Tau] = p1q`1 + p2q`2 + ...  (15)
+
+  This follows independently from (14), assuming the special variations
+  [delta]x = x`dt, &c., and therefore [delta]q1 = q`1dt, [delta]q2 =
+  q`2dt, ...
+
+
+    Reciprocal theorems.
+
+  Again, if the values of the velocities and the momenta in any other
+  motion of the system through the same configuration be distinguished
+  by accents, we have the identity
+
+    p1q`'1 + p2q`'2 + ... = p'1q`1 + p'2q`2 + ...,   (16)
+
+  each side being equal to the symmetrical expression
+
+    A11q`1q''1 + A22q`2q`'2 + ... + A12(q`1q`'2 + q`'1q`2) + ...  (17)
+
+  The theorem (16) leads to some important reciprocal relations. Thus,
+  let us suppose that the momenta p1, p2, ... all vanish with the
+  exception of p1, and similarly that the momenta p'1, p'2, ... all
+  vanish except p'2. We have then p1q`'1 = p'2q`2, or
+
+    q`2 : p1 = q`'1 : p'2                       (18)
+
+  The interpretation is simplest when the co-ordinates q1, q2 are both
+  of the same kind, e.g. both lines or both angles. We may then
+  conveniently put p1 = p'2, and assert that the velocity of the first
+  type due to an impulse of the second type is equal to the velocity of
+  the second type due to an equal impulse of the first type. As an
+  example, suppose we have a chain of straight links hinged each to the
+  next, extended in a straight line, and free to move. A blow at right
+  angles to the chain, at any point P, will produce a certain velocity
+  at any other point Q; the theorem asserts that an equal velocity will
+  be produced at P by an equal blow at Q. Again, an impulsive couple
+  acting on any link A will produce a certain angular velocity in any
+  other link B; an equal couple applied to B will produce an equal
+  angular velocity in A. Also if an impulse F applied at P produce an
+  angular velocity [omega] in a link A, a couple Fa applied to A will
+  produce a linear velocity [omega]a at P. Historically, we may note
+  that reciprocal relations in dynamics were first recognized by H.L.F.
+  Helmholtz in the domain of acoustics; their use has been greatly
+  extended by Lord Rayleigh.
+
+
+    Velocities in terms of momenta.
+
+  The equations (13) determine the momenta p1, p2,... as linear
+  functions of the velocities q`1, q`2,... Solving these, we can
+  express q`1, q`2 ... as linear functions of p1, p2,... The
+  resulting equations give us the velocities produced by any given
+  system of impulses. Further, by substitution in (8), we can express
+  the kinetic energy as a homogeneous quadratic function of the momenta
+  p1, p2,... The kinetic energy, _as so expressed_, will be denoted by
+  [Tau]´; thus
+
+    2[Tau]´ = A´11p1² + A´22p2² + ... + 2A´12p - p2 + ...   (19)
+
+  where A´11, A´22,... A´12,... are certain coefficients depending on
+  the configuration. They have been called by Maxwell the _coefficients
+  of mobility_ of the system. When the form (19) is given, the values
+  of the velocities in terms of the momenta can be expressed in a
+  remarkable form due to Sir W.R. Hamilton. The formula (15) may be
+  written
+
+    p1q`1 + p2q`2 + ... = [Tau] + [Tau]´, ...   (20)
+
+  where [Tau] is supposed expressed as in (8), and [Tau]´ as in (19).
+  Hence if, for the moment, we denote by [delta] a variation affecting
+  the velocities, and therefore the momenta, but not the configuration,
+  we have
+
+    p1[delta]q`1 + q`1[delta]p + p2[delta]q`2 + q`2[delta]p2 + ... = [delta][Tau] + [delta][Tau]´
+
+      dP[Tau]              dP[Tau]                    dP[Tau]´             dP[Tau]´
+    = ------- [delta]q`1 + ------- [delta]q`2 + ... + -------- [delta]p1 + -------- [delta]p2 + ...  (21)
+      dPq`1                dPq`2                       dPp1                 dPp2
+
+  In virtue of (13) this reduces to
+
+                                        dP[Tau]´            dP[Tau]´
+    q`1[delta]p1 + q`2[delta]p2 + ... = ------- [delta]p1 + ------- [delta]p2  + ...  (22)
+                                         dPp1                dPp2
+
+  Since [delta]p1, [delta]p2, ... may be taken to be independent, we
+  infer that
+
+          dP[Tau]´       dP[Tau]´
+    q`1 = -------, q`2 = -------, ...  (23)
+           dPp1           dPp2
+
+  In the very remarkable exposition of the matter given by James Clerk
+  Maxwell in his _Electricity and Magnetism_, the Hamiltonian
+  expressions (23) for the velocities in terms of the impulses are
+  obtained directly from first principles, and the formulae (13) are
+  then deduced by an inversion of the above argument.
+
+
+    Routh's modification.
+
+  An important modification of the above process was introduced by E.J.
+  Routh and Lord Kelvin and P.G. Tait. Instead of expressing the kinetic
+  energy in terms of the velocities alone, or in terms of the momenta
+  alone, we may express it in terms of the velocities corresponding to
+  some of the co-ordinates, say q1, q2, ... q_m, and of the momenta
+  corresponding to the remaining co-ordinates, which (for the sake of
+  distinction) we may denote by [chi], [chi]', [chi]", .... Thus, [Tau]
+  being expressed as a homogeneous quadratic function of q`1, q`2, ...
+  q`_m, [chi]`, [chi]`', [chi]`", ..., the momenta corresponding to the
+  co-ordinates [chi], [chi]', [chi]", ... may be written
+
+               dP[Tau]               dP[Tau]                dP[Tau]
+    [kappa]  = --------, [kappa]' = ---------, [kappa]" = ------------, ...  (24)
+               dP[chi]`             dP[chi]`'              dP[.[chi]`"
+
+  These equations, when written out in full, determine [chi]`, [chi]`',
+  [chi]`", ... as linear functions of q`1, q`2, ... q`_m, [kappa],
+  [kappa]', [kappa]",... We now consider the function
+
+    R = [Tau] - [kappa][chi]' - [kappa]'[chi]]`' - [kappa]"[chi]]`" - ...,  (25)
+
+  supposed expressed, by means of the above relations in terms of q`1,
+  q`2, ... q`_m, [kappa], [kappa]', [kappa]",... Performing the
+  operation [delta] on both sides of (25), we have
+
+     dPR                        dPR                           dP[Tau]                    dP[Tau]
+    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... + -------- [delta][chi]` + ...
+    dPq`1                    dP[kappa]                         dPq`1                     dP[chi]`
+
+       - [kappa]dP[chi]` - [chi]`[delta][kappa] - ... ,   (26)
+
+  where, for brevity, only one term of each type has been exhibited.
+  Omitting the terms which cancel in virtue of (24), we have
+
+     dPR                        dPR                           dP[Tau]
+    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... - [chi]`[delta][kappa] - ...  (27)
+    dPq`1                    dP[kappa]                        dPq`1
+
+  Since the variations [delta]q1, [delta]q2, ... [delta]q_m,
+  [delta][kappa], [delta][kappa]', [delta][kappa]", ... may be taken to
+  be independent, we have
+
+         dP[Tau]     dPR        dP[Tau]     dPR
+    p1 = -------  = -----, p2 = -------  = -----, ...  (28)
+          dPq`1     dPq`1        dPq`2     dPq`2
+
+  and
+
+                  dPR                    dPR                      dPR
+    [chi]` = - ---------, [chi]`' = - ----------, [chi]]`" = - ---------, ...  (29)
+               dP[kappa]              dP[kappa]'               dP[kappa]"
+
+  An important property of the present transformation is that, when
+  expressed in terms of the new variables, the kinetic energy is the sum
+  of two homogeneous quadratic functions, thus
+
+    [Tau] = [@] + K,  (30)
+
+  where [@] involves the velocities q`1, q`2, ... q`_m alone, and K the
+  momenta [kappa], [kappa]', [kappa]", ... alone. For in virtue of (29)
+  we have, from (25),
+
+                 /            dPR                  dPR                    dPR          \
+    [Tau] = R - ( [kappa]  --------- + [kappa]' ---------- + [kappa]" ----------- + ... ),  (31)
+                 \         dP[kappa]            dP[kappa]'             dP[kappa]"      /
+
+  and it is evident that the terms in R which are bilinear in respect of
+  the two sets of variables q`1, q`2, ... q`_m and [kappa], [kappa]',
+  [kappa]", ... will disappear from the right-hand side.
+
+
+    Maximum and minimum energy.
+
+  It may be noted that the formula (30) gives immediate proof of two
+  important theorems due to Bertrand and to Lord Kelvin respectively.
+  Let us suppose, in the first place, that the system is started by
+  given impulses of certain types, but is otherwise free. J.L.F.
+  Bertrand's theorem is to the effect that the kinetic energy is
+  _greater_ than if by impulses of the remaining types the system were
+  constrained to take any other course. We may suppose the co-ordinates
+  to be so chosen that the constraint is expressed by the vanishing of
+  the velocities q`1, q`2, ... q`_m, whilst the given impulses are
+  [kappa], [kappa]', [kappa]",... Hence the energy in the actual motion
+  is greater than in the constrained motion by the amount [@].
+
+  Again, suppose that the system is started with prescribed velocity
+  components q`1, q`2, ... q`_m, by means of proper impulses of
+  the corresponding types, but is otherwise free, so that in the motion
+  actually generated we have [kappa] = 0, [kappa]' = 0, [kappa]" = 0,
+  ... and therefore K = 0. The kinetic energy is therefore _less_ than
+  in any other motion consistent with the prescribed velocity-conditions
+  by the value which K assumes when [kappa], [kappa]', [kappa]", ...
+  represent the impulses due to the constraints.
+
+  Simple illustrations of these theorems are afforded by the chain of
+  straight links already employed. Thus if a point of the chain be held
+  fixed, or if one or more of the joints be made rigid, the energy
+  generated by any given impulses is less than if the chain had
+  possessed its former freedom.
+
+
+  2. _Continuous Motion of a System._
+
+    Lagrange's equations.
+
+  We may proceed to the continuous motion of a system. The equations of
+  motion of any particle of the system are of the form
+
+    mx¨ = X, my¨ = Y, mz¨ = Z  (1)
+
+  Now let x + [delta]x, y + [delta]y, z + [delta]z be the co-ordinates
+  of m in any arbitrary motion of the system differing infinitely little
+  from the actual motion, and let us form the equation
+
+    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) =
+       [Sigma](X[delta]x + Y[delta]y + Z[delta]z) (2)
+
+  Lagrange's investigation consists in the transformation of (2) into an
+  equation involving the independent variations [delta]q1, [delta]q2,
+  ... [delta]q_n.
+
+  It is important to notice that the symbols [delta] and d/dt are
+  commutative, since
+
+                d                  dx   d
+    [delta]x` = --(x + [delta]x) - -- = --[delta]x, &c. (3)
+                dt                 dt   dt
+
+  Hence
+
+                                                     d
+    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) = -- [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)
+                                                     dt
+      - [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)
+
+        d
+      = --(p1[delta]q1 + p2[delta]q2 + ...) - [delta][Tau],  (4)
+        dt
+
+  by § 1 (14). The last member may be written
+
+    p`1[delta]q1 + p1[delta]q`1 + p`2[delta]q2 + p2[delta]q`2 + ...
+
+        dP[Tau]              dP[Tau]             dP[Tau]              dP[Tau]
+      - ------- [delta]q`1 - ------- [delta]q1 - ------- [delta]q`2 - ------- [delta]q2 - ... (5)
+         dPq`1                dPq1                dPq`2                dPq2
+
+  Hence, omitting the terms which cancel in virtue of § 1 (13), we find
+
+                                                      /     dP[Tau]\               /     dP[Tau]\
+    [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) = (p`1 - ------- ) [delta]q1 + (p`2 - ------- ) [delta]q2 + ... (6)
+                                                      \      dPq1  /               \       dPq2 /
+
+  For the right-hand side of (2) we have
+
+    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = Q1[delta]q1 + Q2[delta]q2  + ..., (7)
+
+                      /   dPx       dPy       dPz \
+  where Q_r = [Sigma]( X ----- + Y ----- + Z ----- )  (8)
+                      \  dPq_r     dPq_r     dPq_r/
+
+  The quantities Q1, Q2, ... are called the _generalized components of
+  force_ acting on the system.
+
+  Comparing (6) and (7) we find
+
+          dP[Tau]             dP[Tau]
+    p`1 - ------- = Q1, p`2 - ------- = Q2, ...,  (9)
+           dPq`1               dPq`2
+
+  or, restoring the values of p1, p2, ...,
+
+    d   /dP[Tau]\    dP[Tau]       d   /dP[Tau]\    dP[Tau]
+    -- ( ------- ) - ------- = Q1, -- ( ------- ) - ------- = Q2, ... (10)
+    dt  \ dPq`1 /     dPq1         dt  \ dPq`2 /      dPq2
+
+  These are Lagrange's general equations of motion. Their number is of
+  course equal to that of the co-ordinates q1, q2, ... to be determined.
+
+  Analytically, the above proof is that given by Lagrange, but the
+  terminology employed is of much more recent date, having been first
+  introduced by Lord Kelvin and P.G. Tait; it has greatly promoted the
+  physical application of the subject. Another proof of the equations
+  (10), by direct transformation of co-ordinates, has been given by
+  Hamilton and independently by other writers (see MECHANICS), but the
+  variational method of Lagrange is that which stands in closest
+  relation to the subsequent developments of the subject. The chapter of
+  Maxwell, already referred to, is a most instructive commentary on the
+  subject from the physical point of view, although the proof there
+  attempted of the equations (10) is fallacious.
+
+  In a "conservative system" the work which would have to be done by
+  extraneous forces to bring the system from rest in some standard
+  configuration to rest in the configuration (q1, q2, ... q_n) is
+  independent of the path, and may therefore be regarded as a definite
+  function of q1, q2, ... q_n. Denoting this function (the _potential
+  energy_) by V, we have, if there be no extraneous force on the system,
+
+    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = - [delta]V,  (11)
+
+  and therefore
+
+           dPV          dPV
+    Q1 = - ----, Q2 = - ----, ....  (12)
+           dPq1         dPq2
+
+  Hence the typical Lagrange's equation may be now written in the form
+
+    d   /dP[Tau]\    dP[Tau]      dPV
+    -- ( ------- ) - ------- = - -----,  (13)
+    dt  \dPq`_r /     dPq_r      dPq_r
+
+  or, again,
+
+              dP
+    p`_r = - ----- (V - [Tau])  (14)
+             dPq_r
+
+  It has been proposed by Helmholtz to give the name _kinetic potential_
+  to the combination V - [Tau].
+
+  As shown under MECHANICS, § 22, we derive from (10)
+
+    d[Tau]
+    ------ = Q1q`1 + Q2q`2 + ...,  (15)
+      dt
+
+  and therefore in the case of a conservative system free from
+  extraneous force,
+
+    d
+    --([Tau] + V) = 0 or [Tau] + V = const.,  (16)
+    dt
+
+  which is the equation of energy. For examples of the application of
+  the formula (13) see MECHANICS, § 22.
+
+
+  3. _Constrained Systems._
+
+    Case of varying relations.
+
+  It has so far been assumed that the geometrical relations, if any,
+  which exist between the various parts of the system are of the type §
+  1 (1), and so do not contain t explicitly. The extension of Lagrange's
+  equations to the case of "varying relations" of the type
+
+    x = f(t, q1, q2,...q_n), y = &c., z = &c.,  (1)
+
+  was made by J.M.L. Vieille. We now have
+
+         dPx   dPx        dPx
+    x` = --- + ---- q`1 + ---- q`2 + ..., &c., &c.,  (2)
+         dPt   dPq1       dPq2
+
+          dPx              dPx
+    dPx = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.,  (3)
+          dPq1             dPq2
+
+  so that the expression § 1 (8) for the kinetic energy is to be
+  replaced by
+
+    2[Tau] = [alpha]0 + 2[alpha]1q`1 + 2[alpha]2q`2 + ... + A11q`1² + A22q`2² + ... + A12q`1q`2 + ..., (4)
+
+  where
+                   _                           _         \
+                  | /dPx\²    /dPy\²    /dPz\²  |         |
+    a0 = [Sigma]m |( --- ) + ( --- ) + ( --- )  |,        |
+                  |_\dPt/     \dPt/     \dPt/  _|         |
+                    _                                 _    >  (5)
+                   | dPx  dPx    dPy  dPy    dPz  dPz  |  |
+    a_r = [Sigma]m | --- ----- + --- ----- + --- ----- |, |
+                   |_dPt dPq_r   dPt dPq_r   dPt dPq_r_|  |
+                                                         /
+
+  and the forms of A_rr, A_rs are as given by § 1 (7). It is to be
+  remembered that the coefficients [alpha]0, [alpha]1, [alpha]2, ...
+  A11, A22, ... A12 ... will in general involve t explicitly as well as
+  implicitly through the co-ordinates q1, q2,... Again, we find
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+
+        ([alpha]1 + A11q`1 + A12q`2 + ...)[delta]q1
+            + ([alpha]2 + A21q`1 + A22q`2 + ...)dPq2 + ...
+
+          dP[Tau]             dP[Tau]
+        = ------- [delta]q1 + ------- [delta]q2 + ...
+           dPq`1               dPq`2
+
+        = p1[delta]q1 + p2[delta]q2 + ...,  (6)
+
+  where p_r is defined as in § 1 (13). The derivation of Lagrange's
+  equations then follows exactly as before. It is to be noted that the
+  equation § 2 (15) does not as a rule now hold. The proof involved the
+  assumption that [Tau] is a homogeneous quadratic function of the
+  velocities q`1, q`2....
+
+  It has been pointed out by R.B. Hayward that Vieille's case can be
+  brought under Lagrange's by introducing a new co-ordinate ([chi]) in
+  place of t, so far as it appears explicitly in the relations (1). We
+  have then
+
+    2[Tau] = [alpha]0[chi]`² + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
+        + A11q`1² + A22q`2² + ... + 2A12q`1q`2 + .... (7)
+
+  The equations of motion will be as in § 2 (10), with the additional
+  equation
+
+    d  dP[Tau]    dP[Tau]
+    -- -------- - ------- = X,  (8)
+    dt dP[chi]`   dP[chi]
+
+  where X is the force corresponding to the co-ordinate [chi]. We may
+  suppose X to be adjusted so as to make [chi]¨ = 0, and in the
+  remaining equations nothing is altered if we write t for [chi] before,
+  instead of after, the differentiations. The reason why the equation §
+  2 (15) no longer holds is that we should require to add a term X[chi]`
+  on the right-hand side; this represents the rate at which work is
+  being done by the constraining forces required to keep [chi]`
+  constant.
+
+  As an example, let x, y, z be the co-ordinates of a particle relative
+  to axes fixed in a solid which is free to rotate about the axis of z.
+  If [phi] be the angular co-ordinate of the solid, we find without
+  difficulty
+
+    2[Tau] = m(x`² + y`² +z`²) + 2[phi]`m(xy` - yx`) + {I + m(x² + y²)}[phi]`², (9)
+
+  where I is the moment of inertia of the solid. The equations of
+  motion, viz.
+
+    d  dP[Tau]  dP[Tau]     d  dP[Tau]   dP[Tau]      d  dP[Tau]   dP[Tau]
+    -- ------ - ------ = X, -- ------- - ------- = Y, -- ------- - ------- = Z, (10)
+    dt  dPx`     dPx        dt   dPy`      dPy        dt   dPz`      dPz
+
+      d   dP[Tau]   dP[Tau]
+  and -- -------- - ------- = [Phi],  (11)
+      dt dP[phi]`   dP[phi]
+
+  become
+
+    m(x¨ - 2[phi]`y` - x[phi]`² - y[phi]¨) = X, m(y¨ + 2[phi]`x` - y[phi]`² + x[phi]`) = Y, mz¨ = Z, (12)
+          _                                    _
+      d  | /            \                       |
+  and -- |(I + m(x² + y²)) [phi]` + m(xy` - yx`)| = [Phi].  (13)
+      dt |_\            /                      _|
+
+  If we suppose [Phi] adjusted so as to maintain [phi]¨ = 0, or (again)
+  if we suppose the moment of inertia I to be infinitely great, we
+  obtain the familiar equations of motion relative to moving axes, viz.
+
+    m(x¨ - 2[omega]y` - [omega]²x) = X, m(y¨ + 2[omega]x` - [omega]²y) = Y, mz¨ = Z, (14)
+
+  where [omega] has been written for [phi]. These are the equations
+  which we should have obtained by applying Lagrange's rule at once to
+  the formula
+
+    2[Tau] = m(x`² + y`² + z`²) + 2m[omega](xy` - yx`) + m[omega]²(x² + y²), (15)
+
+  which gives the kinetic energy of the particle referred to axes
+  rotating with the constant angular velocity [omega]. (See MECHANICS, §
+  13.)
+
+  More generally, let us suppose that we have a certain group of
+  co-ordinates [chi], [chi]', [chi]", ... whose absolute values do not
+  affect the expression for the kinetic energy, and that by suitable
+  forces of the corresponding types the velocity-components [chi]`,
+  [chi]`', [chi]`", ... are maintained constant. The remaining
+  co-ordinates being denoted by q1, q2, ... q_n, we may write
+
+    2[Tau] = [@] + [Tau]0 + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
+        + 2([alpha]'1q`1 + [alpha]'2q`2 + ...)[chi]`' + ...,  (16)
+
+  where [@] is a homogeneous quadratic function of the velocities q`1,
+  q`2, ... q`_n of the type §1 (8), whilst [Tau]0 is a homogeneous
+  quadratic function of the velocities [chi]`,[chi]`', [chi]`", ...
+  alone. The remaining terms, which are bilinear in respect of the two
+  sets of velocities, are indicated more fully. The formulae (10) of § 2
+  give n equations of the type
+
+    d  /dP[@]\     /dP[@]\                                  dP[Tau]0
+    --( ----- ) - ( ----- ) + (r, 1)q`1 + (r, 2)q`2 + ... - -------- = Q_r (17)
+    dt \dPq_r/     \dPq_r/                                    dPq_r
+
+  where
+
+              /dPa_r   dPa_s\           /dPa'_r   dPa'_s\
+    (r, s) = ( ----- - ----- )[chi]` + ( ------ - ------ )[chi]`' + .... (18)
+              \dPq_s   dPq_r/           \dPq_s     dPq_r/
+
+  These quantities (r, s) are subject to the relations
+
+    (r, s) = -(s, r), (r, r) = 0  (19)
+
+  The remaining dynamical equations, equal in number to the co-ordinates
+  [chi], [chi]', [chi]", ..., yield expressions for the forces which
+  must be applied in order to maintain the velocities [chi]`, [chi]`',
+  [chi]`", ... constant; they need not be written down. If we follow the
+  method by which the equation of energy was established in § 2, the
+  equations (17) lead, on taking account of the relations (19), to
+
+    d
+    --([@] - [Tau]0) = Q1q`1 + Q2q`2 + ... + Q_nq`_n,  (20)
+    dt
+
+  or, in case the forces Q_r depend only on the co-ordinates q1, q2, ...
+  q_n and are conservative,
+
+    [@] + V - [Tau]0 = const.  (21)
+
+  The conditions that the equations (17) should be satisfied by zero
+  values of the velocities q`1, q`2, ... q`_n are
+
+            dP[Tau]0
+    Q_r = - --------,  (22)
+             dPq_r
+
+  or in the case of conservative forces
+
+    dP
+    ------ (V - [Tau]0) = 0,  (23)
+    dPq_r
+
+  i.e. the value of V - [Tau]0 must be _stationary_.
+
+
+    Rotating axes.
+
+  We may apply this to the case of a system whose configuration relative
+  to axes rotating with constant angular velocity ([omega]) is defined
+  by means of the n co-ordinates q1, q2, ... q_n. This is important on
+  account of its bearing on the kinetic theory of the tides. Since the
+  Cartesian co-ordinates x, y, z of any particle m of the system
+  relative to the moving axes are functions of q1, q2, ... q_n, of the
+  form § 1 (1), we have, by (15)
+
+    2[@] = [Sigma]m(x`² + y`² + z`²), 2[Tau]0 = [omega]²[Sigma]m(x² + y²),  (24)
+
+                  /  dPy      dPx \
+    a_r= [Sigma]m( x----- - y----- ),  (25)
+                  \ dPq_r    dPq_r/
+
+  whence
+
+                                 dP(x, y)
+    (r, s) = 2[omega]·[Sigma]m ------------.  (26)
+                               dP(q_s, q_r)
+
+  The conditions of relative equilibrium are given by (23).
+
+  It will be noticed that this expression V - [Tau]0, which is to be
+  stationary, differs from the true potential energy by a term which
+  represents the potential energy of the system in relation to
+  fictitious "centrifugal forces." The question of stability of relative
+  equilibrium will be noticed later (§ 6).
+
+  It should be observed that the remarkable formula (20) may in the
+  present case be obtained directly as follows. From (15) and (14) we
+  find
+
+    d[Tau]   d
+    ------ = --([@] + [Tau]0) + [omega]·[Sigma]m(xy¨ - yx¨)
+      dt     dt
+
+        d
+      = --([@] - [Tau]0) + [omega]·[Sigma](xY - yX).  (27)
+        dt
+
+  This must be equal to the rate at which the forces acting on the
+  system do work, viz. to
+
+    [omega][Sigma](xY - yX) + Q1q`1 + Q2q`2 + ... + Q_nq`_n,
+
+  where the first term represents the work done in virtue of the
+  rotation.
+
+
+    Constrained systems.
+
+  We have still to notice the modifications which Lagrange's equations
+  undergo when the co-ordinates q1, q2, ... q_n are not all
+  independently variable. In the first place, we may suppose them
+  connected by a number m ( < n) of relations of the type
+
+    A(t, q1, q2, ... q_n) = 0, B(t, q1, q2, ... q_n) = 0, &c.  (28)
+
+  These may be interpreted as introducing partial constraints into a
+  previously free system. The variations [delta]q1, [delta]q2, ...
+  [delta]q_n in the expressions (6) and (7) of § 2 which are to be
+  equated are no longer independent, but are subject to the relations
+
+    dPA              dPA                       dPB              dPB
+    ---- [delta]q1 + ---- [delta]q2 + ... = 0, ---- [delta]q1 + ---- [delta]q2 + ... = 0, &c.  (29)
+    dPq1             dPq2                      dPq1             dPq2
+
+  Introducing indeterminate multipliers [lambda], µ, ..., one for each
+  of these equations, we obtain in the usual manner n equations of the
+  type
+
+    d  dP[Tau]   dP[Tau]                   dPA       dPB
+    -- ------- - ------- = Q_r + [lambda] ----- + µ ----- + ..., (30)
+    dt dPq`_r     dPq_r                   dPq_r     dPq_r
+
+  in place of § 2 (10). These equations, together with (28), serve to
+  determine the n co-ordinates q1, q2, ... q_n and the m multipliers
+  [lambda], µ, ....
+
+  When t does not occur explicitly in the relations (28) the system is
+  said to be _holonomic_. The term connotes the existence of integral
+  (as opposed to differential) relations between the co-ordinates,
+  independent of the time.
+
+  Again, it may happen that although there are no prescribed relations
+  between the co-ordinates q1, q2, ... q_n, yet from the circumstances
+  of the problem certain geometrical conditions are imposed on their
+  _variations_, thus
+
+    A1[delta]q1 + A2[delta]q2 + ... = 0, B1[delta]q1 + B2[delta]q2 + ... = 0, &c., (31)
+
+  where the coefficients are functions of q1, q2, ... q_n and (possibly)
+  of t. It is assumed that these equations are not integrable as regards
+  the variables q1, q2, ... q_n; otherwise, we fall back on the previous
+  conditions. Cases of the present type arise, for instance, in ordinary
+  dynamics when we have a solid rolling on a (fixed or moving) surface.
+  The six co-ordinates which serve to specify the position of the solid
+  at any instant are not subject to any necessary relation, but the
+  conditions to be satisfied at the point of contact impose three
+  conditions of the form (31). The general equations of motion are
+  obtained, as before, by the method of indeterminate multipliers, thus
+
+    d  dP[Tau]   dP[Tau]
+    -- ------- - ------- = Q_r + [lambda]A_r + µB_r + ...  (32)
+    dt dPq`_r     dPq_r
+
+  The co-ordinates q1, q2, ... q_n, and the indeterminate multipliers
+  [lambda], µ, ..., are determined by these equations and by the
+  velocity-conditions corresponding to (31). When t does not appear
+  explicitly in the coefficients, these velocity-conditions take the
+  forms
+
+    A1q`1 + A2q`2 + ... = 0, B1q`1 + B2q`2 + ... = 0, &c.  (33)
+
+  Systems of this kind, where the relations (31) are not integrable, are
+  called _non-holonomic_.
+
+
+  4. _Hamiltonian Equations of Motion._
+
+  In the Hamiltonian form of the equations of motion of a conservative
+  system with unvarying relations, the kinetic energy is supposed
+  expressed in terms of the _momenta_ p1, p2, ... and the co-ordinates
+  q1, q2, ..., as in § 1 (19). Since the symbol [delta] now denotes a
+  variation extending to the co-ordinates as well as to the momenta, we
+  must add to the last member of § 1 (21) terms of the types
+
+    dP[Tau]             dP[Tau]'
+    ------- [delta]q1 + -------- [delta]q1 + ...  (1)
+     dPq1                 dPq1
+
+  Since the variations [delta]p1, [delta]p2, ... [delta]q1, [delta]q2,
+  ... may be taken to be independent, we infer the equations § 1 (23) as
+  before, together with
+
+    dP[Tau]    dP[Tau]´  dP[Tau]     dP[Tau]´
+    ------ = - --------, ------- = - --------, ...,  (2)
+     dPq1        dPq1     dPq2         dPq2
+
+  Hence the Lagrangian equations § 2 (14) transform into
+
+             dP                      dP
+    p`1 = - ----([Tau]´ + V), p`2 = ---- ([Tau]´ + V), ...  (3)
+            dPq1                    dPq2
+
+  If we write
+
+    H = [Tau]´ + V,  (4)
+
+  so that H denotes the _total energy_ of the system, supposed expressed
+  in terms of the new variables, we get
+
+            dPH           dPH
+    p`1 = - ----, p`2 = - ----, ...  (5)
+            dPq1          dPq2
+
+  If to these we join the equations
+
+          dPH         dPH
+    q`1 = ----, q`2 = ----, ...,  (6)
+          dPp1        dPp2
+
+
+  which follow at once from § 1 (23), since V does not involve p1, p2,
+  ..., we obtain a complete system of differential equations _of the
+  first order_ for the determination of the motion.
+
+  The equation of energy is verified immediately by (5) and (6), since
+  these make
+
+    dH   dPH        dPH              dPH        dPH
+    -- = ---- p`1 + ---- p`2 + ... + ---- q`1 + ---- q`2 + ... = 0. (7)
+    dt   dPp1       dPp2             dPq1       dPq2
+
+  The Hamiltonian transformation is extended to the case of varying
+  relations as follows. Instead of (4) we write
+
+    H = p1q`1 + p2q`2 + ... - [Tau] + V,  (8)
+
+  and imagine H to be expressed in terms of the momenta p1, p2, ..., the
+  co-ordinates q1, q2, ..., and the time. The internal forces of the
+  system are assumed to be conservative, with the potential energy V.
+  Performing the variation [delta] on both sides, we find
+
+                                    dP[Tau]             dPV
+    [delta]H = q`1[delta]p1 + ... - ------- [delta]q1 + ---- [delta]q + ...,  (9)
+                                     dPq1               dPq1
+
+  terms which cancel in virtue of the definition of p1, p2, ... being
+  omitted. Since [delta]p1, [delta]p2, ..., [delta]q1, [delta]q2, ...
+  may be taken to be independent, we infer
+
+          dPH         dPH
+    q`1 = ----, q`2 = ----, ...,  (10)
+          dPp1        dPp2
+
+  and
+
+     dP                  dPH    dP                 dPH
+    ---- ([Tau] - V) = - ----, ----([Tau] - V) = - ----, ....  (11)
+    dPq1                 dPq1  dPq2                dPq2
+
+  It follows from (11) that
+
+            dPH           dPH
+    p`1 = - ----, p`2 = - ----, ....  (12)
+            dPq1          dPq2
+
+  The equations (10) and (12) have the same form as above, but H is no
+  longer equal to the energy of the system.
+
+
+  5. _Cyclic Systems._
+
+  A _cyclic_ or _gyrostatic_ system is characterized by the following
+  properties. In the first place, the kinetic energy is not affected if
+  we alter the absolute values of certain of the co-ordinates, which we
+  will denote by [chi], [chi]', [chi]", ..., provided the remaining
+  co-ordinates q1, q2, ... q_m and the velocities, including of course
+  the velocities [.[chi]], [.[chi]]', [.[chi]]", ..., are unaltered.
+  Secondly, there are no forces acting on the system of the types [chi],
+  [chi]', [chi]", .... This case arises, for example, when the system
+  includes gyrostats which are free to rotate about their axes, the
+  co-ordinates [chi], [chi]', [chi]", ... then being the angular
+  co-ordinates of the gyrostats relatively to their frames. Again, in
+  theoretical hydrodynamics we have the problem of moving solids in a
+  frictionless liquid; the ignored co-ordinates [chi], [chi]', [chi]",
+  ... then refer to the fluid, and are infinite in number. The same
+  question presents itself in various physical speculations where
+  certain phenomena are ascribed to the existence of _latent motions_ in
+  the ultimate constituents of matter. The general theory of such
+  systems has been treated by E.J. Routh, Lord Kelvin, and H.L.F.
+  Helmholtz.
+
+
+    Routh's equations.
+
+  If we suppose the kinetic energy [Tau] to be expressed, as in
+  Lagrange's method, in terms of the co-ordinates and the velocities,
+  the equations of motion corresponding to [chi], [chi]', [chi]'´, ...
+  reduce, in virtue of the above hypotheses, to the forms
+
+    d  dP[Tau]        d   dP[Tau]       d   dP[Tau]
+    -- --------- = 0, -- --------- = 0, -- --------- = 0, ...,  (1)
+    dt dP[chi]`       dt dP[chi]`'      dt dP[chi]`"
+
+  whence
+
+     dP[Tau]             dP[Tau]               dP[Tau]
+    -------- = [kappa], --------- = [kappa]', --------- = [kappa]", ..., (2)
+    dP[chi]`            dP[chi]`'             dP[chi]`"
+
+  where [kappa], [kappa]', [kappa]", ... are the constant momenta
+  corresponding to the cyclic co-ordinates [chi], [chi]', [chi]", ....
+  These equations are linear in [.[chi]], [.[chi]]', [.[chi]]", ...;
+  solving them with respect to these quantities and substituting in the
+  remaining Lagrangian equations, we obtain m differential equations to
+  determine the remaining co-ordinates q1, q2, ... q_m. The object of
+  the present investigation is to ascertain the general form of the
+  resulting equations. The retained co-ordinates q1, q2, ... q_m may be
+  called (for distinction) the _palpable_ co-ordinates of the system; in
+  many practical questions they are the only co-ordinates directly in
+  evidence.
+
+  If, as in § 1 (25), we write
+
+    R = [Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ..., (3)
+
+  and imagine R to be expressed by means of (2) as a quadratic function
+  of q`1, q`2, ... q`_m, [kappa], [kappa]', [kappa]", ... with
+  coefficients which are in general functions of the co-ordinates q1,
+  q2, ... q_m, then, performing the operation [delta] on both sides, we
+  find
+
+     dPR                       dPR                          dPR                   dP[Tau]                   dP[Tau]
+    -----[delta]q`1 + ... + ---------[delta][kappa] + ... + ----[delta]q1 + ... = -------[delta]q`1 + ... + -------[delta]q1 + ...
+    dPq`1                   dP[kappa]                       dPq1                   dPq`1                     dPq1
+
+         dP[Tau]                      dP[Tau]
+      + --------[delta][chi]` + ... + --------[delta]q1 + ... - [kappa][delta][chi]` - [chi]`[delta][kappa] - .... (4)
+        dP[chi]`                      dP[chi]1
+
+  Omitting the terms which cancel by (2), we find
+
+    dP[Tau]    dPR   dP[Tau]    dPR
+    ------- = -----, ------- = -----, ...,  (5)
+     dPq`1    dPq`1   dPq`2    dPq`2
+
+    dP[Tau]   dPR   dP[Tau]   dPR
+    ------- = ----, ------- = ----, ...,  (6)
+     dPq1     dPq1   dPq2     dPq2
+
+                    dPR                    dPR                     dPR
+    [chi]`  =  - ---------, [chi]`' = - ----------, [chi]`" = - ----------, ... (7)
+                 dP[kappa]              dP[kappa]'              dP[kappa]"
+
+  Substituting in § 2 (10), we have
+
+    d   dPR     dPR        d   dPR    dPR
+    -- ----- - ----- = Q1, -- ----- - ---- = Q2, ...  (8)
+    dt dPq`1   dPq1        dt dPq`2   dPq2
+
+  These are Routh's forms of the modified Lagrangian equations.
+  Equivalent forms were obtained independently by Helmholtz at a later
+  date.
+
+
+    Kelvin's equations.
+
+  The function R is made up of three parts, thus
+
+    R = R(2,0) + R(1,1) + R(0,2), ...  (9)
+
+  where R(2,0) is a homogeneous quadratic function of q`1, q`2, ...
+  q`_m, R(0,2) is a homogeneous quadratic function of [kappa], [kappa]',
+  [kappa]", ..., whilst R(1,1) consists of products of the velocities
+  q`1, q`2, ... q`_m into the momenta [kappa], [kappa]', [kappa]"....
+  Hence from (3) and (7) we have
+
+                 /           dPR                 dPR                   dPR         \
+    [Tau] = R - ( [kappa] --------- + [kappa]'---------- + [kappa]" ---------- + ...)
+                 \        dP[kappa]           dP[kappa]'            dP[kappa]"     /
+
+      = R(2,0) - R(0,2).  (10)
+
+  If, as in § 1 (30), we write this in the form
+
+    [Tau] = [@] + [Kappa],  (11)
+
+  then (3) may be written
+
+    R = [@] - [Kappa] + ß1q`1 + ß2q`2 + ...,  (12)
+
+  where ß1, ß2, ... are linear functions of [kappa], [kappa]', [kappa]",
+  ..., say
+
+    ß_r = [alpha]_r[kappa] + [alpha]'_r[kappa]' + [alpha]"_r[kappa]" + ..., (13)
+
+  the coefficients [alpha]_r, [alpha]'_r, [alpha]"_r, ... being in
+  general functions of the co-ordinates q1, q2, ... q_m. Evidently ß_r
+  denotes that part of the momentum-component dPR/dPq`_r which is due to
+  the cyclic motions. Now
+
+    d   dPR      d  / dP[@]     \    d   dP[@]   dPß_r      dPß_r
+    -- ------ = -- ( ------ + ß_r) = -- ------ + -----q`1 + -----q`2 + ..., (14)
+    dt dPq`_r   dt  \dPq`_r     /    dt dPq`_r    dPq1       dPq2
+
+     dPR    dP[@]   dP[Kappa]   dPß1       dPß2
+    ----- = ----- - --------- + -----q`1 + -----q`2 + .... (15)
+    dPq_r   dPq_r     dPq_r     dPq_r      dPq_r
+
+  Hence, substituting in (8), we obtain the typical equation of motion
+  of a gyrostatic system in the form
+
+    d   dP[@]   dP[@]                                                    dP[Kappa]
+    -- ------ - ----- + (r, 1)q`1 + (r, 2)q`2 + ... + (r, s)q`_s + ... + --------- = Q_r, (16)
+    dt dPq`_r   dPq_r                                                      dPq_r
+
+  where
+
+             dPß_r   dPß_s
+    (r, s) = ----- - -----.  (17)
+             dPq_s   dPq_r
+
+  This form is due to Lord Kelvin. When q1, q2, ... q_m have been
+  determined, as functions of the time, the velocities corresponding to
+  the cyclic co-ordinates can be found, if required, from the relations
+  (7), which may be written
+
+             dP[Kappa]                                        \
+    [Chi]` = --------- - [alpha]1q`1 - [alpha]2q`2 - ...,     |
+             dP[kappa]                                        |
+                                                              |
+              dP[Kappa]                                        >  (18)
+    [Chi]`' = ---------- - [alpha]'1q`1 - [alpha]'2q`2 - ..., |
+              dP[kappa]'                                      |
+                                                              |
+       &c., &c.                                               /
+
+  It is to be particularly noticed that
+
+    (r, r) = 0, (r, s) = -(s, r).  (19)
+
+  Hence, if in (16) we put r = 1, 2, 3, ... m, and multiply by q`1,
+  q`2, ... q`_m respectively, and add, we find
+
+    d
+    --([@] + [Kappa]) = Q1q`1 + Q2q`2 + ...,  (20)
+    dt
+
+  or, in the case of a conservative system
+
+    [@] + V + [Kappa] = const.,  (21)
+
+  which is the equation of energy.
+
+  The equation (16) includes § 3 (17) as a particular case, the
+  eliminated co-ordinate being the angular co-ordinate of a rotating
+  solid having an infinite moment of inertia.
+
+  In the particular case where the cyclic momenta [kappa], [kappa]',
+  [kappa]", ... are all zero, (16) reduces to
+
+    d   dP[@]   dP[@]
+    -- ------ - ----- = Q_r.  (22)
+    dt dPq`_r   dPq_r
+
+  The form is the same as in § 2, and the system now behaves, as regards
+  the co-ordinates q1, q2, ... q_m, exactly like the acyclic type there
+  contemplated. These co-ordinates do not, however, now fix the position
+  of every particle of the system. For example, if by suitable forces
+  the system be brought back to its initial configuration (so far as
+  this is defined by q1, q2, ..., q_m), after performing any evolutions,
+  the ignored co-ordinates [chi], [chi]', [chi]", ... will not in
+  general return to their original values.
+
+  If in Lagrange's equations § 2 (10) we reverse the sign of the
+  time-element dt, the equations are unaltered. The motion is therefore
+  reversible; that is to say, if as the system is passing through any
+  configuration its velocities q`1, q`2, ..., q`_m be all
+  reversed, it will (if the forces be the same in the same
+  configuration) retrace its former path. But it is important to observe
+  that the statement does not in general hold of a gyrostatic system;
+  the terms of (16), which are linear in q`1, q`2, ..., q`_m,
+  change sign with dt, whilst the others do not. Hence the motion of a
+  gyrostatic system is not reversible, unless indeed we reverse the
+  cyclic motions as well as the velocities q`1, q`2, ..., q`_m.
+  For instance, the precessional motion of a top cannot be reversed
+  unless we reverse the spin.
+
+
+    Kinetostatics.
+
+  The _conditions of equilibrium_ of a system with latent cyclic motions
+  are obtained by putting q`1 = 0, q`2 = 0, ... q`_m = 0 in (16); viz.
+  they are
+
+         dP[Kappa]       dP[Kappa]
+    Q1 = ---------, Q2 = ---------, ...  (23)
+           dPq1            dPq2
+
+  These may of course be obtained independently. Thus if the system be
+  guided from (apparent) rest in the configuration (q1, q2, ... q_m) to
+  rest in the configuration q1 + [delta]q1, q2 + [delta]q2, ..., q_m +
+  [delta]q_m, the work done by the forces must be equal to the increment
+  of the kinetic energy. Hence
+
+    Q1[delta]q1 + Q2[delta]q2 + ... = [delta][Kappa],  (24)
+
+  which is equivalent to (23). The conditions are the same as for the
+  equilibrium of a system without latent motion, but endowed with
+  potential energy [Kappa]. This is important from a physical point of
+  view, as showing how energy which is apparently potential may in its
+  ultimate essence be kinetic.
+
+  By means of the formulae (18), which now reduce to
+
+             dP[Kappa]            dP[Kappa]             dP[Kappa]
+    [chi]` = ---------, [chi]`' = ----------, [chi]`" = ---------- ..., (25)
+             dP[kappa]            dP[kappa]'            dP[kappa]"
+
+  [Kappa] may also be expressed as a homogeneous quadratic function of
+  the cyclic velocities [.[chi]], [.[chi]]', [.[chi]]", ... Denoting it
+  in this form by [Tau]0, we have
+
+    [delta]([Tau]0 + [Kappa] = 2[delta][Kappa] = [delta]([kappa] [chi]` + [kappa]'[chi]`' + [kappa]"[chi]`" +  ...). (26)
+
+  Performing the variations, and omitting the terms which cancel by (2)
+  and (25), we find
+
+    dP[Tau]0     dP[Kappa]  dP[Tau]0     dP[Kappa]
+    -------- = - ---------, -------- = - ---------, ...,  (27)
+      dPq1         dPq1       dPq2         dPq2
+
+  so that the formulae (23) become
+
+           dP[Tau]0         dP[Tau]0
+    Q1 = - --------, Q2 = - --------, ...  (28)
+             dPq1             dPq2
+
+  A simple example is furnished by the top (MECHANICS, § 22). The cyclic
+  co-ordinates being [psi], [phi], we find
+
+                                  (µ - [nu] cos [theta])²   [nu]²
+    2[@] = A[theta]`², 2[Kappa] = ----------------------- + -----,
+                                      A sin² [theta]          C
+
+      2[Tau]0 = A sin²[theta][psi]`² + C([phi]` + [psi] cos [theta])², (29)
+
+  whence we may verify that dP[Tau]0/dP[theta] = - dP[Kappa]/dP[theta]
+  in accordance with (27). And the condition of equilibrium
+
+    dP[Kappa]        dPV
+    --------- = - ---------  (30)
+    dP[theta]     dP[theta]
+
+  gives the condition of steady precession.
+
+
+  6. _Stability of Steady Motion._
+
+  The small oscillations of a conservative system about a configuration
+  of equilibrium, and the criterion of stability, are discussed in
+  MECHANICS, § 23. The question of the stability of given types of
+  motion is more difficult, owing to the want of a sufficiently general,
+  and at the same time precise, definition of what we mean by
+  "stability." A number of definitions which have been propounded by
+  different writers are examined by F. Klein and A. Sommerfeld in their
+  work _Über die Theorie des Kreisels_ (1897-1903). Rejecting previous
+  definitions, they base their criterion of stability on the character
+  of the changes produced in the _path_ of the system by small arbitrary
+  disturbing impulses. If the undisturbed path be the _limiting form_ of
+  the disturbed path when the impulses are indefinitely diminished, it
+  is said to be stable, but not otherwise. For instance, the vertical
+  fall of a particle under gravity is reckoned as stable, although for a
+  _given_ impulsive disturbance, however small, the deviation of the
+  particle's position at any time t from the position which it would
+  have occupied in the original motion increases indefinitely with t.
+  Even this criterion, as the writers quoted themselves recognize, is
+  not free from ambiguity unless the phrase "limiting form," as applied
+  to a path, be strictly defined. It appears, moreover, that a
+  definition which is analytically precise may not in all cases be easy
+  to reconcile with geometrical prepossessions. Thus a particle moving
+  in a circle about a centre of force varying inversely as the cube of
+  the distance will if slightly disturbed either fall into the centre,
+  or recede to infinity, after describing in either case a spiral with
+  an infinite number of convolutions. Each of these spirals has,
+  analytically, the circle as its limiting form, although the motion in
+  the circle is most naturally described as unstable.
+
+  A special form of the problem, of great interest, presents itself in
+  the steady motion of a gyrostatic system, when the non-eliminated
+  co-ordinates q1, q2, ... q_m all vanish (see § 5). This has been
+  discussed by Routh, Lord Kelvin and Tait, and Poincaré. These writers
+  treat the question, by an extension of Lagrange's method, as a problem
+  of small oscillations. Whether we adopt the notion of stability which
+  this implies, or take up the position of Klein and Sommerfeld, there
+  is no difficulty in showing that stability is ensured if V + [Kappa]
+  be a minimum as regards variations of q1, q2, ... q_m. The proof is
+  the same as that of Dirichlet for the case of statical stability.
+
+  We can illustrate this condition from the case of the top, where, in
+  our previous notation,
+
+                                   (µ - [nu]cos [theta])²   [nu]²
+    V + [Kappa] = Mgh cos[theta] + ---------------------- + -----. (1)
+                                       2A sin² [theta]       2C
+
+  To examine whether the steady motion with the centre of gravity
+  vertically above the pivot is stable, we must put µ = [nu]. We then
+  find without difficulty that V + [Kappa] is a minimum provided [nu]²
+  [>=] 4AMgh. The method of small oscillations gave us the condition
+  [nu]² > 4AMgh, and indicated instability in the cases [nu]² [=<]
+  4AMgh. The present criterion can also be applied to show that the
+  steady precessional motions in which the axis has a constant
+  inclination to the vertical are stable.
+
+  The question remains, as before, whether it is _essential_ for
+  stability that V + [Kappa] should be a minimum. It appears that from
+  the point of view of the theory of small oscillations it is not
+  essential, and that there may even be stability when V + [Kappa] is a
+  maximum. The precise conditions, which are of a somewhat elaborate
+  character, have been formulated by Routh. An important distinction
+  has, however, been established by Thomson and Tait, and by Poincaré,
+  between what we may call _ordinary_ or _temporary_ stability (which is
+  stability in the above sense) and _permanent_ or _secular_ stability,
+  which means stability when regard is had to possible dissipative
+  forces called into play whenever the co-ordinates q1, q2, ... q_m
+  vary. Since the total energy of the system at any instant is given (in
+  the notation of § 5) by an expression of the form [@] + V +
+  [Kappa], where [@] cannot be negative, the argument of Thomson
+  and Tait, given under MECHANICS, § 23, for the statical question,
+  shows that it is a necessary as well as a sufficient condition for
+  secular stability that V + [Kappa] should be a minimum. When a system
+  is "ordinarily" stable, but "secularly" unstable, the operation of the
+  frictional forces is to induce a gradual increase in the amplitude of
+  the free vibrations which are called into play by accidental
+  disturbances.
+
+  There is a similar theory in relation to the constrained systems
+  considered in § 3 above. The equation (21) there given leads to the
+  conclusion that for secular stability of any type of motion in which
+  the velocities q`1, q`2, ... q`_n are zero it is necessary and
+  sufficient that the function V - [Tau]0 should be a minimum.
+
+  The simplest possible example of this is the case of a particle at the
+  lowest point of a smooth spherical bowl which rotates with constant
+  angular velocity ([omega]) about the vertical diameter. This position
+  obviously possesses "ordinary" stability. If a be the radius of the
+  bowl, and [theta] denote angular distance from the lowest point, we
+  have
+
+    V - [Tau]0 = mga(1 - cos [theta]) - ½m[omega]²a² sin² [theta];  (2)
+
+  this is a minimum for [theta] = 0 only so long as [omega]² < g/a. For
+  greater values of [omega] the only position of "permanent" stability
+  is that in which the particle rotates with the bowl at an angular
+  distance cos^(-1) (g/[omega]²a) from the lowest point. To examine the
+  motion in the neighbourhood of the lowest point, when frictional
+  forces are taken into account, we may take fixed ones, in a horizontal
+  plane, through the lowest point. Assuming that the friction varies as
+  the relative velocity, we have
+
+    x¨ = -p²x - k(x` + [omega]y),  \  (3)
+    y¨ = -p²y - k(y` - [omega]x),  /
+
+  where p² = g/a. These combine into
+
+    z¨ + kz` + (p² - ik[omega])z = 0,  (4)
+
+  where z = x + iy, i = [root]-1. Assuming z = Ce^([lambda]t), we find
+
+    [lambda] = -½k(1 [-+] [omega]/p) ± ip,  (5)
+
+  if the square of k be neglected. The complete solution is then
+
+    x + iy = C1e^(-ß1t)e^(ipt) + C2e^(-ß2t)e^(-ipt),  (6)
+
+  where ß1 = ½k(1 - [omega]/p), ß2 = ½k(1 + [omega]/p). (7)
+
+  This represents two superposed circular vibrations, in opposite
+  directions, of period 2[pi]/p. If [omega] < p, the amplitude of each
+  of these diminishes asymptotically to zero, and the position x = 0, y
+  = 0 is permanently stable. But if [omega] > p the amplitude of that
+  circular vibration which agrees in sense with the rotation [omega]
+  will continually increase, and the particle will work its way in an
+  ever-widening spiral path towards the eccentric position of secular
+  stability. If the bowl be not spherical but ellipsoidal, the vertical
+  diameter being a principal axis, it may easily be shown that the
+  lowest position is permanently stable only so long as the period of
+  the rotation is longer than that of the slower of the two normal
+  modes in the absence of rotation (see MECHANICS, § 13).
+
+
+  7. _Principle of Least Action._
+
+    Stationary Action.
+
+  The preceding theories give us statements applicable to the system at
+  any one instant of its motion. We now come to a series of theorems
+  relating to the whole motion of the system between any two
+  configurations through which it passes, viz. we consider the actual
+  motion and compare it with other imaginable motions, differing
+  infinitely little from it, between the same two configurations. We use
+  the symbol [delta] to denote the transition from the actual to any one
+  of the hypothetical motions.
+
+  The best-known theorem of this class is that of _Least Action_,
+  originated by P.L.M. de Maupertuis, but first put in a definite form
+  by Lagrange. The "action" of a single particle in passing from one
+  position to another is the space-integral of the momentum, or the
+  time-integral of the _vis viva_. The action of a dynamical system is
+  the sum of the actions of its constituent particles, and is
+  accordingly given by the formula
+                 _                _            _
+                /                /            /
+    A = [Sigma] | mvds = [Sigma] |  mv²dt = 2 | [Tau]dt.  (1)
+               _/               _/           _/
+
+  The theorem referred to asserts that the free motion of a conservative
+  system between any two given configurations is characterized by the
+  property
+
+    [delta]A = 0,  (2)
+
+  provided the total energy have the same constant value in the varied
+  motion as in the actual motion.
+
+  If t, t' be the times of passing through the initial and final
+  configurations respectively, we have
+                        _
+                       / t'
+    [delta]A = [delta] |  [Sigma]m(x`² + y`² + z`²)dt
+                      _/t
+                _
+               / t'
+           = 2 |  [delta][Tau]dt + 2[Tau]'[delta]t' + 2[Tau][delta]t, (3)
+              _/t
+
+  since the upper and lower limits of the integral must both be regarded
+  as variable. This may be written
+                _                   _
+               / t'                / t'
+    [delta]A = |  [delta][Tau]dt + |  [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t
+              _/t                 _/t
+         _                   _                                              _
+        / t'                |                                                | t'
+      = |  [delta][Tau]dt + | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z |
+       _/t                  |_                                              _| t
+           _
+          / t'
+        - |  [Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t. (4)
+         _/t
+
+  Now, by d'Alembert's principle,
+
+    [Sigma]m( x¨[delta]x + y¨[delta]y + z¨[delta]z ) = -[delta]V,  (5)
+
+  and by hypothesis we have
+
+    [delta]([Tau] + V) = 0.  (6)
+
+  The formula therefore reduces to
+                _                                               _
+               |                                                 |t'
+    [delta]A = | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z) | + 2[Tau]'[delta]t' - 2[Tau][delta]t. (7)
+               |_                                               _|t
+
+  Since the terminal configurations are unaltered, we must have at the
+  lower limit
+
+    [delta]x + x`[delta]t = 0, [delta]y + y`[delta]t = 0, [delta]z + z`[delta]t = 0, (8)
+
+  with similar relations at the upper limit. These reduce (7) to the
+  form (2).
+
+  The equation (2), it is to be noticed, merely expresses that the
+  variation of A vanishes _to the first order_; the phrase _stationary
+  action_ has therefore been suggested as indicating more accurately
+  what has been proved. The action in the free path between two given
+  configurations is in fact not invariably a minimum, and even when a
+  minimum it need not be the _least possible_ subject to the given
+  conditions. Simple illustrations are furnished by the case of a single
+  particle. A particle moving on a smooth surface, and free from
+  extraneous force, will have its velocity constant; hence the theorem
+  in this case resolves itself into
+             _
+            /
+    [delta] | ds = 0,  (9)
+           _/
+
+  i.e. the path must be a geodesic line. Now a geodesic is not
+  necessarily the _shortest_ path between two given points on it; for
+  example, on the sphere a great-circle arc ceases to be the shortest
+  path between its extremities when it exceeds 180°. More generally,
+  taking any surface, let a point P, starting from O, move along a
+  geodesic; this geodesic will be a minimum path from O to P until P
+  passes through a point O' (if such exist), which is the intersection
+  with a consecutive geodesic through O. After this point the minimum
+  property ceases. On an anticlastic surface two geodesics cannot
+  intersect more than once, and each geodesic is therefore a minimum
+  path between any two of its points. These illustrations are due to
+  K.G.J. Jacobi, who has also formulated the general criterion,
+  applicable to all dynamical systems, as follows:--Let O and P denote
+  any two configurations on a natural path of the system. If this be the
+  sole free path from O to P with the prescribed amount of energy, the
+  action from O to P is a minimum. But if there be several distinct
+  paths, let P vary from coincidence with O along the first-named path;
+  the action will then cease to be a minimum when a configuration O' is
+  reached such that two of the possible paths from O to O' coincide. For
+  instance, if O and P be positions on the parabolic path of a
+  projectile under gravity, there will be a second path (with the same
+  energy and therefore the same velocity of projection from O), these
+  two paths coinciding when P is at the other extremity (O', say) of the
+  focal chord through O. The action from O to P will therefore be a
+  minimum for all positions of P short of O'. Two configurations such as
+  O and O' in the general statement are called conjugate _kinetic foci_.
+  Cf. VARIATIONS, CALCULUS OF.
+
+  Before leaving this topic the connexion of the principle of stationary
+  action with a well-known theorem of optics may be noticed. For the
+  motion of a particle in a conservative field of force the principle
+  takes the form
+             _
+            /
+    [delta] | vds = 0.  (10)
+           _/
+
+  On the corpuscular theory of light v is proportional to the refractive
+  index µ of the medium, whence
+             _
+            /
+    [delta] | µds = 0.  (11)
+           _/
+
+
+    Hamiltonian principle.
+
+  In the formula (2) the energy in the hypothetical motion is
+  prescribed, whilst the time of transit from the initial to the final
+  configuration is variable. In another and generally more convenient
+  theorem, due to Hamilton, the time of transit is prescribed to be the
+  same as in the actual motion, whilst the energy may be different and
+  need not (indeed) be constant. Under these conditions we have
+             _
+            /t'
+    [delta] | ([Tau] - V)dt = 0,  (12)
+           _/t
+
+  where t, t' are the prescribed times of passing through the given
+  initial and final configurations. The proof of (12) is simple; we have
+             _                 _                               _
+            /t'               /t'                             /t'
+    [delta] | ([Tau] - V)dt = | ([delta][Tau] - [delta]V)dt = |  {[Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`) - [delta]V}dt
+           _/t               _/t                             _/t
+         _                                              _
+        |                                                |t'
+      = | [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) |
+        |_                                              _|t
+       _
+      /t'
+    - | {[Sigma]m(x¨[delta]x + y¨[delta]y + z¨[delta]z) + [delta]V}dt (13)
+     _/t
+
+  The integrated terms vanish at both limits, since by hypothesis the
+  configurations at these instants are fixed; and the terms under the
+  integral sign vanish by d'Alembert's principle.
+
+  The fact that in (12) the variation does not affect the time of
+  transit renders the formula easy of application in any system of
+  co-ordinates. Thus, to deduce Lagrange's equations, we have
+
+      _                             _
+     /t'                           /t'/dP[Tau]             dP[Tau]                  dPV               \
+     | ([delta][Tau]-[delta]V)dt = | ( -------[delta]q`1 + -------[delta]q1 + ... - ----[delta]q1 - ...)dt
+    _/t                           _/t \ dPq`1               dPq1                    dPq1              /
+         _                               _
+        |                                 |t'
+      = | p1[delta]q1 + p2[delta]q2 + ... |
+        |_                               _|t
+
+       _  _                                                                        _
+      /t'|  /     dP[Tau]   dPV \              /     dP[Tau]    dPV\                |
+    - |  | (p`1 - ------- + ---- )[delta]q1 + (p`2 - ------- + -----)[delta]q2 + ...|dt. (14)
+     _/t |_ \      dPq1     dPq1/              \      dPq2     dPq2/               _|
+
+  The integrated terms vanish at both limits; and in order that the
+  remainder of the right-hand member may vanish it is necessary that the
+  coefficients of [delta]q1, [delta]q2, ... under the integral sign
+  should vanish for all values of t, since the variations in question
+  are independent, and subject only to the condition of vanishing at the
+  limits of integration. We are thus led to Lagrange's equation of
+  motion for a conservative system. It appears that the formula (12) is
+  a convenient as well as a compact embodiment of the whole of ordinary
+  dynamics.
+
+
+    Extension to cyclic systems.
+
+  The modification of the Hamiltonian principle appropriate to the case
+  of cyclic systems has been given by J. Larmor. If we write, as in § 1
+  (25),
+
+    R = T - [kappa][chi]` - [kappa]'[chi]`' - [kappa]'´[chi]`" - ..., (15)
+
+  we shall have
+             _
+            /t'
+    [delta] | (R - V)dt = 0,  (16)
+           _/t
+
+  provided that the variation does not affect the cyclic momenta
+  [kappa], [kappa]', [kappa]", ..., and that the configurations at times
+  t and t' are unaltered, so far as they depend on the palpable
+  co-ordinates q1, q2, ... q_m. The initial and final values of the
+  ignored co-ordinates will in general be affected.
+
+  To prove (16) we have, on the above understandings,
+             _             _
+            /t'           /t'
+    [delta] | (R - V)dt = | ([delta][Tau] - [kappa][delta][chi]` - ... -[delta]V)dt
+           _/t           _/t
+         _
+        /t' /dP[Tau]                   dP[Tau]                          \
+      = |  ( -------[delta]q`1 + ... + -------[delta]q1 + ... - [delta]V )dt,  (17)
+       _/t  \ dPq`1                     dPq1                            /
+
+  where terms have been cancelled in virtue of § 5 (2). The last member
+  of (17) represents a variation of the integral
+      _
+     /t'
+     | ([Tau] - V)dt
+    _/t
+
+  on the supposition that [delta]X = 0, [delta]X' = 0, [delta]X" = 0,
+  ... throughout, whilst [delta]q1, [delta]q2, [delta]q_m vanish at
+  times t and t'; i.e. it is a variation in which the initial and final
+  configurations are absolutely unaltered. It therefore vanishes as a
+  consequence of the Hamiltonian principle in its original form.
+
+  Larmor has also given the corresponding form of the principle of least
+  action. He shows that if we write
+         _
+        /
+    A = |(2[Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ...)dt, (18)
+       _/
+
+  then
+
+    [delta]A = 0,  (19)
+
+  provided the varied motion takes place with the same constant value of
+  the energy, and with the same constant cyclic momenta, between the
+  same two configurations, these being regarded as defined by the
+  palpable co-ordinates alone.
+
+
+  § 8. _Hamilton's Principal and Characteristic Functions._
+
+    Principal function.
+
+  In the investigations next to be described a more extended meaning is
+  given to the symbol [delta]. We will, in the first instance, denote by
+  it an infinitesimal variation of the most general kind, affecting not
+  merely the values of the co-ordinates at any instant, but also the
+  initial and final configurations and the times of passing through
+  them. If we put
+         _
+        /t'
+    S = | (T - V)dt,  (1)
+       _/t
+
+  we have, then,
+                                                       _
+                                                      /t'
+    [delta]S = (T' - V')[delta]t' - (T - V)[delta]t + | ([delta]T - [delta]V)dt
+                                                     _/t
+                                                _                                            _
+                                               |                                              |t'
+      = (T' - V')[delta]t' - (T - V)[delta]t + |[Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)|  (2)
+                                               |_                                            _|t
+
+  Let us now denote by x' + [delta]x', y' + [delta]y', z' + [delta]z',
+  the final co-ordinates (i.e. at time t' + [delta]t') of a particle m.
+  In the terms in (2) which relate to the upper limit we must therefore
+  write [delta]x' - x`'[delta]t', [delta]y' - y`'[delta]t',
+  [delta]z' - z`'[delta]t' for [delta]x, [delta]y, [delta]z. With a
+  similar modification at the lower limit, we obtain
+
+    [delta]S = - H[delta][tau] + [Sigma]m(x`'[delta]x' + y`'[delta]y' + z`'[delta]z')
+      - [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z),  (3)
+
+  where H(= T + V) is the constant value of the energy in the free
+  motion of the system, and [tau](= t' - t) is the time of transit. In
+  generalized co-ordinates this takes the form
+
+    [delta]S = - H[delta][tau] + p'1[delta]q'1 + p'2[delta]q'2 + ...
+      - p1[delta]q1 - p2[delta]q2 - ....  (4)
+
+  Now if we select any two arbitrary configurations as initial and
+  final, it is evident that we can in general (by suitable initial
+  velocities or impulses) start the system so that it will of itself
+  pass from the first to the second in any prescribed time [tau]. On
+  this view of the matter, S will be a function of the initial and final
+  co-ordinates (q1, q2, ... and q'1, q'2, ...) and the time [tau], as
+  independent variables. And we obtain at once from (4)
+
+           dPS          dPS        \
+    p'1 = -----, p'2 = -----, ..., |
+          dPq'1        dPq'2       |
+                                    >  (5)
+           dPS          dPS        |
+    p1 = - ----, p2 = - ----, ..., |
+           dPq1         dPq2       /
+
+              dPS
+  and H = - -------.                            (6)
+            dP[tau]
+
+  S is called by Hamilton the _principal function_; if its general form
+  for any system can be found, the preceding equations suffice to
+  determine the motion resulting from any given conditions. If we
+  substitute the values of p1, p2, ... and H from (5) and (6) in the
+  expression for the kinetic energy in the form [Tau]' (see § 1), the
+  equation
+
+    T¹ + V = H  (7)
+
+  becomes a partial differential equation to be satisfied by S. It has
+  been shown by Jacobi that the dynamical problem resolves itself into
+  obtaining a "complete" solution of this equation, involving n + 1
+  arbitrary constants. This aspect of the subject, as a problem in
+  partial differential equations, has received great attention at the
+  hands of mathematicians, but must be passed over here.
+
+
+    Characteristic function.
+
+  There is a similar theory for the function
+           _
+          /
+    A = 2 | Tdt = S + H[tau]  (8)
+         _/
+
+  It follows from (4) that
+
+    [delta]A = [tau][delta]H + p'1[delta]q'1 + p'2[delta]q'2 + ...
+      - p1[delta]q1 - p2[delta]q2 - ....  (9)
+
+  This formula (it may be remarked) contains the principle of "least
+  action" as a particular case. Selecting, as before, any two arbitrary
+  configurations, it is in general possible to start the system from one
+  of these, with a prescribed value of the total energy H, so that it
+  shall pass through the other. Hence, regarding A as a function of the
+  initial and final co-ordinates and the energy, we find
+
+           dPA          dPA        \
+    p'1 = -----, p'2 = -----, ..., |
+          dPq'1        dPq'2       |
+                                    >  (10)
+           dPA          dPA        |
+    p1 = - ----, p2 = - ----, ..., |
+           dPq1         dPq2       /
+
+              dPA
+  and [tau] = ---   (11)
+              dPH
+
+  A is called by Hamilton the _characteristic function_; it represents,
+  of course, the "action" of the system in the free motion (with
+  prescribed energy) between the two configurations. Like S, it
+  satisfies a partial differential equation, obtained by substitution
+  from (10) in (7).
+
+  The preceding theorems are easily adapted to the case of cyclic
+  systems. We have only to write
+         _            _
+        /t'          /t'
+    S = | (R - V)dt= | (T - [kappa][chi]` - [kappa]'[chi]`' - ... - V)dt (12)
+       _/t          _/t
+
+  in place of (1), and
+         _
+        /
+    A = | (2T - [kappa][chi]` - [kappa]'[chi]`' - ...)dt,  (3)
+       _/
+
+  in place of (8); cf. § 7 ad fin. It is understood, of course, that in
+  (12) S is regarded as a function of the initial and final values of
+  the palpable co-ordinates q1, q2, ... q_m, and of the time of transit
+  [tau], the cyclic momenta being invariable. Similarly in (13), A is
+  regarded as a function of the initial and final values of q1, q2, ...
+  q_m, and of the total energy H, with the cyclic momenta invariable. It
+  will be found that the forms of (4) and (9) will be conserved,
+  provided the variations [delta]q1, [delta]q2, ... be understood to
+  refer to the palpable co-ordinates alone. It follows that the
+  equations (5), (6) and (10), (11) will still hold under the new
+  meanings of the symbols.
+
+
+  9. _Reciprocal Properties of Direct and Reversed Motions._
+
+    Lagrange's formula.
+
+  We may employ Hamilton's principal function to prove a very remarkable
+  formula connecting any _two_ slightly disturbed natural motions of the
+  system. If we use the symbols [delta] and [Delta] to denote the
+  corresponding variations, the theorem is
+
+    d
+    --[Sigma]([delta]p_r·[Delta]q_r - [Delta]p_r·[delta]q_r) = 0;  (1)
+    dt
+
+  or integrating from t to t',
+
+    [Sigma]([delta]p'_r·[Delta]q'_r - [Delta]q'_r·[delta]q'_r) = [Sigma]([delta]p_r·[Delta]q_r - [Delta]p_r·[delta]q_r). (2)
+
+  If for shortness we write
+
+               dP²S                 dP²S
+    (r,s) = ----------, (r,s') = -----------,  (3)
+            dPq_rdPq_s           dPq_rdPq'_s
+
+  we have
+
+    dPp_r = - [Sigma]_s(r,s)[delta]q_s - [Sigma]_s(r,s')[delta]q'_s  (4)
+
+  with a similar expression for [Delta]p_r. Hence the right-hand side of
+  (2) becomes
+
+    - [Sigma]_r{[Sigma]_s(r,s)[delta]q_s + [Sigma]_s(r,s')[delta]q'_s}[Delta]q_r
+      + [Sigma]_r{[Sigma]_s(r,s)[Delta]q_s + [Sigma]_s(r,s')[Delta]q'_s}[delta]q_r
+        = [Sigma]_r[Sigma]_s(r,s'){[delta]q_r·[Delta]q'_s - [Delta]q_r·[delta]q'_s}. (5)
+
+  The same value is obtained in like manner for the expression on the
+  left hand of (2); hence the theorem, which, in the form (1), is due to
+  Lagrange, and was employed by him as the basis of his method of
+  treating the dynamical theory of _Variation of Arbitrary Constants_.
+
+
+    Helmholtz's reciprocal theorems.
+
+  The formula (2) leads at once to some remarkable reciprocal relations
+  which were first expressed, in their complete form, by Helmholtz.
+  Consider any natural motion of a conservative system between two
+  configurations O and O' through which it passes at times t and t'
+  respectively, and let t' - t = [tau]. As the system is passing through
+  O let a small impulse [delta]p_r be given to it, and let the
+  consequent alteration in the co-ordinate q_s after the time [tau] be
+  [delta]q'_s. Next consider the _reversed_ motion of the system, in
+  which it would, if undisturbed, pass from O' to O in the same time
+  [tau]. Let a small impulse [delta]p'_s be applied as the system is
+  passing through O', and let the consequent change in the co-ordinate
+  q_r after a time [tau] be [delta]q_r. Helmholtz's first theorem is to
+  the effect that
+
+    [delta]q_r : [delta]p'_s = [delta]q'_s : [delta]p_r.  (6)
+
+  To prove this, suppose, in (2), that all the [delta]q vanish, and
+  likewise all the [delta]p with the exception of [delta]p_r. Further,
+  suppose all the [Delta]q' to vanish, and likewise all the [Delta]p'
+  except [Delta]p'_s, the formula then gives
+
+    [delta]p_r·[Delta]q_r = - [Delta]p'_s·[delta]q'_s,  (7)
+
+  which is equivalent to Helmholtz's result, since we may suppose the
+  symbol [Delta] to refer to the reversed motion, provided we change
+  the signs of the [Delta]p. In the most general motion of a top
+  (MECHANICS, § 22), suppose that a small impulsive couple about the
+  vertical produces after a time [tau] a change [delta][theta] in the
+  inclination of the axis, the theorem asserts that in the reversed
+  motion an equal impulsive couple in the plane of [theta] will produce
+  after a time [tau] a change [delta][psi], in the azimuth of the axis,
+  which is equal to [delta][theta]. It is understood, of course, that
+  the couples have no components (in the generalized sense) except of
+  the types indicated; for instance, they may consist in each case of a
+  force applied to the top at a point of the axis, and of the
+  accompanying reaction at the pivot. Again, in the corpuscular theory
+  of light let O, O' be any two points on the axis of a symmetrical
+  optical combination, and let V, V' be the corresponding velocities of
+  light. At O let a small impulse be applied perpendicular to the axis
+  so as to produce an angular deflection [delta][theta], and let ß'
+  be the corresponding lateral deviation at O'. In like manner in the
+  reversed motion, let a small deflection [delta][theta]' at O' produce
+  a lateral deviation ß at O. The theorem (6) asserts that
+
+            ß                  ß'
+    ----------------- = ---------------,  (8)
+    V'[delta][theta]'   V[delta][theta]
+
+  or, in optical language, the "apparent distance" of O from O' is to
+  that of O' from O in the ratio of the refractive indices at O' and O
+  respectively.
+
+
+    Helmholtz's second reciprocal theorem.
+
+  In the second reciprocal theorem of Helmholtz the configuration O is
+  slightly varied by a change [delta]q_r in one of the co-ordinates, the
+  momenta being all unaltered, and [delta]q'_s is the consequent
+  variation in one of the momenta after time [tau]. Similarly in the
+  reversed motion a change [delta]p'_s produces after time [tau] a
+  change of momentum [delta]p_r. The theorem asserts that
+
+    [delta]p'_s : [delta]q_r = [delta]p_r : [delta]q'_s  (9)
+
+  This follows at once from (2) if we imagine all the [delta]p to
+  vanish, and likewise all the [delta]q save [delta]q_r, and if
+  (further) we imagine all the [Delta]p' to vanish, and all the
+  [Delta]q' save [Delta]q'_s. Reverting to the optical illustration, if
+  F, F', be principal foci, we can infer that the convergence at F' of a
+  parallel beam from F is to the convergence at F of a parallel beam
+  from F' in the inverse ratio of the refractive indices at F' and F.
+  This is equivalent to Gauss's relation between the two principal focal
+  lengths of an optical instrument. It may be obtained otherwise as a
+  particular case of (8).
+
+  We have by no means exhausted the inferences to be drawn from
+  Lagrange's formula. It may be noted that (6) includes as particular
+  cases various important reciprocal relations in optics and acoustics
+  formulated by R.J.E. Clausius, Helmholtz, Thomson (Lord Kelvin) and
+  Tait, and Lord Rayleigh. In applying the theorem care must be taken
+  that in the reversed motion the reversal is complete, and extends to
+  every velocity in the system; in particular, in a cyclic system the
+  cyclic motions must be imagined to be reversed with the rest.
+  Conspicuous instances of the failure of the theorem through incomplete
+  reversal are afforded by the propagation of sound in a wind and the
+  propagation of light in a magnetic medium.
+
+  It may be worth while to point out, however, that there is no such
+  limitation to the use of Lagrange's formula (1). In applying it to
+  cyclic systems, it is convenient to introduce conditions already laid
+  down, viz. that the co-ordinates q_r are the palpable co-ordinates and
+  that the cyclic momenta are invariable. Special inference can then be
+  drawn as before, but the interpretation cannot be expressed so neatly
+  owing to the non-reversibility of the motion.
+
+  AUTHORITIES.--The most important and most accessible early authorities
+  are J.L. Lagrange, _Mécanique analytique_ (1st ed. Paris, 1788, 2nd
+  ed. Paris, 1811; reprinted in _Oeuvres_, vols. xi., xii., Paris,
+  1888-89); Hamilton, "On a General Method in Dynamics," _Phil. Trans._
+  1834 and 1835; C.G.J. Jacobi, _Vorlesungen über Dynamik_ (Berlin,
+  1866, reprinted in _Werke_, Supp.-Bd., Berlin, 1884). An account of
+  the extensive literature on the differential equations of dynamics and
+  on the theory of variation of parameters is given by A. Cayley,
+  "Report on Theoretical Dynamics," _Brit. Assn. Rep._ (1857),
+  _Mathematical Papers_, vol. iii. (Cambridge, 1890). For the modern
+  developments reference may be made to Thomson and Tait, _Natural
+  Philosophy_ (1st ed. Oxford, 1867, 2nd ed. Cambridge, 1879); Lord
+  Rayleigh, _Theory of Sound_, vol. i. (1st ed. London, 1877; 2nd ed.
+  London, 1894); E.J. Routh, _Stability of Motion_ (London, 1877), and
+  _Rigid Dynamics_ (4th ed. London, 1884); H. Helmholtz, "Über die
+  physikalische Bedeutung des Prinzips der kleinsten Action," _Crelle_,
+  vol. c., 1886, reprinted (with other cognate papers) in _Wiss. Abh._
+  vol. iii. (Leipzig, 1895); J. Larmor, "On Least Action," _Proc. Lond.
+  Math. Soc._ vol. xv. (1884); E.T. Whittaker, _Analytical Dynamics_
+  (Cambridge, 1904). As to the question of stability, reference may be
+  made to H. Poincaré, "Sur l'équilibre d'une masse fluide animée d'un
+  mouvement de rotation" _Acta math._ vol. vii. (1885); F. Klein and A.
+  Sommerfeld, _Theorie des Kreisels_, pts. 1, 2 (Leipzig, 1897-1898); A.
+  Lioupanoff and J. Hadamard, _Liouville_, 5me série, vol. iii. (1897);
+  T.J.I. Bromwich, Proc. Lond. Math. Soc. vol. xxxiii. (1901). A
+  remarkable interpretation of various dynamical principles is given by
+  H. Hertz in his posthumous work _Die Prinzipien der Mechanik_
+  (Leipzig, 1894), of which an English translation appeared in 1900.
+       (H. Lb.)
+
+
+
+
+DYNAMITE (Gr. [Greek: dynamis], power), the name given to several
+explosive preparations containing nitroglycerin (q.v.) which are almost
+exclusively used for blasting purposes. The first practical application
+of nitroglycerin in this way was made by A. Nobel in 1863. He soaked
+gunpowder with the liquid and fired the gunpowder by an ordinary fuse.
+Later he found that nitroglycerin could be detonated by the explosion of
+several materials such as fulminate of mercury, the use of which as a
+detonator he patented in 1867. In 1866-1867 he experimented with
+charcoal and other substances, and found the infusorial earth known as
+kieselguhr, which consists mainly of silica (nearly 95%), eminently
+adapted to the purpose, as it was inert, non-combustible, and after a
+little heating and preparation very porous, retaining a large amount of
+nitroglycerin as water is held in a sponge, without very serious
+exudation on standing. This kieselguhr dynamite is generally made by
+incorporating three parts of nitroglycerin with one part of the dry
+earth, the paste being then formed into cylindrical cartridges. This
+work is done by hand. Generally a small percentage of the kieselguhr is
+replaced by a mixture containing sodium and ammonium carbonates, talc
+and ochre. This product is known as dynamite No. 1. Disabilities
+attaching to kieselguhr dynamite are that when placed in water the
+nitroglycerin is liable to be exuded or displaced, also that, like
+nitroglycerin itself, it freezes fairly easily and thawing the frozen
+cartridges is a dangerous operation. Other substances, e.g. kaolin,
+tripoli, magnesia alba (magnesium carbonate), alumina, sugar, charcoal,
+some powdered salts and mixtures of sawdust and salts, have been shown
+to be absorbents more or less adapted to the purpose of making a
+dynamite. Charcoal from cork is said to absorb about 90% of its weight
+of nitroglycerin. With the idea of obtaining greater safety, mixtures
+have been made of nitroglycerin with wood fibre, charcoal and metallic
+nitrates. Lithofracteur, for instance, consists of 50% nitroglycerin and
+a mixture of prepared sawdust, kieselguhr and barium nitrate. Carbonite
+contains 25% of nitroglycerin, the remainder being a mixture of
+wood-meal and alkali nitrates, with about 1% of sulphur. Dualin, atlas
+dynamite and potentite are other modifications.
+
+A convenient form in which nitroglycerin can be made up for blasting
+purposes, especially in wet ground, is the gelatinous material obtained
+by the action of nitroglycerin, either alone or with the help of
+solvents, on low-grade or soluble gun-cottons. It is known as blasting
+gelatin, and was first made by Nobel by incorporating 6 or 7% of low
+nitrated cellulose (collodion cotton or soluble gun-cotton) with
+slightly warmed nitroglycerin. The result is a transparent plastic
+material, of specific gravity 1.5 to 1.6, which may be kept under water
+for a long time without appreciable change. It is less sensitive to
+detonation than ordinary dynamite, and although its explosion is
+slightly slower it is more powerful than dynamite and much superior to
+the liquid nitroglycerin. Blasting gelatin also freezes and is sensitive
+to percussion in this state. Camphor and other substances have been
+added to blasting gelatin to render it more solid and less sensitive.
+Some modifications of blasting gelatin, e.g. gelignite, contain
+wood-meal and such oxygen-containing salts as potassium nitrate.
+Experience has conclusively shown that dynamites are more satisfactory,
+quicker, and more intense in action than liquid nitroglycerin.
+
+To prevent nitroglycerin and some of the forms of dynamite from freezing
+it has been proposed to add to them small quantities of either
+monochlor-dinitroglycerin or of a nitrated poly-glycerin. The former is
+obtained by first acting upon glycerin with hydrogen chloride to produce
+_u-_chlorhydrin or chlor-propylene glycol, C3H7O2Cl, which is then
+nitrated as in the case of glycerin. The latter is obtained by heating
+glycerin for six or seven hours to about 300° C., whereby water is split
+off in such manner that a diglycerin C6H14O5, for the most part,
+results. This on nitration in the usual manner gives a product
+C6H{10}N4O{13}, which burns and explodes in a similar manner to ordinary
+nitroglycerin, but is less sensitive and does not so easily freeze. The
+mono- and di-nitrates of glycerin have also been proposed as additions
+to ordinary nitroglycerin (q.v.) for the same purpose.     (W. R. E. H.)
+
+
+
+
+DYNAMO (a shortened form of "dynamo-electric machine," from Gr. [Greek:
+dynamis], power), a machine for converting mechanical into electrical
+energy.
+
+The dynamo ranks with the telegraph and telephone as one of the three
+striking applications of electrical and magnetic science to which the
+material progress that marked the second half of the 19th century was in
+no small measure due. Since the discovery of the principle of the dynamo
+by Faraday in 1831 the simple model which he first constructed has been
+gradually developed into the machines of 5000 horse-power or more which
+are now built to meet the needs of large cities for electric lighting
+and power, while at the same time the numbers of dynamos in use have
+increased almost beyond estimate. Yet such was the insight of Faraday
+into the fundamental nature of the dynamo that the theory of its action
+which he laid down has remained essentially unchanged. His experiments
+on the current which was set up in a coil of wire during its movement
+across the poles of a magnet led naturally to the explanation of induced
+electromotive force as caused by the linking or unlinking of magnetic
+lines of flux with an electric circuit. For the more definite case of
+the dynamo, however, we may, with Faraday, make the transition from
+line-linkage to the equivalent conception of "line-cutting" as the
+source of E.M.F.--in other words, to the idea of electric conductors
+"cutting" or intersecting[1] the lines of flux in virtue of relative
+motion of the magnetic field and electric circuit. On the 28th of
+October 1831 Faraday mounted a copper disk so that it could be rotated
+edgewise between the poles of a permanent horse-shoe magnet. When so
+rotated, it cut the lines of flux which passed transversely through its
+lower half, and by means of two rubbing contacts, one on its periphery
+and the other on its spindle, the circuit was closed through a
+galvanometer, which indicated the passage of a continuous current so
+long as the disk was rotated (fig. 1). Thus by the invention of the
+first dynamo Faraday proved his idea that the E.M.F. induced through the
+interaction of a magnetic field and an electric circuit was due to the
+passage of a portion of the electric circuit _across_ the lines of flux,
+or vice versa, and so could be maintained if the cutting of the lines
+were made continuous.[2] In comparison with Faraday's results, the
+subsequent advance is to be regarded as a progressive perfecting of the
+mechanical and electro-magnetic design, partly from the theoretical and
+partly from the practical side, rather than as modifying or adding to
+the idea which was originally present in his mind, and of which he
+already saw the possibilities.
+
+[Illustration: FIG. 1.]
+
+A dynamo, then, is a machine in which, by means of continuous relative
+motion, an electrical conductor or system of conductors forming part of
+a circuit is caused to cut the lines of a magnetic field or fields; the
+cutting of the magnetic flux induces an electromotive force in the
+conductors, and when the circuit is closed a current flows, whereby
+mechanical energy is converted into electrical energy.
+
+  Little practical use could be made of electrical energy so long as its
+  only known sources were frictional machines and voltaic batteries. The
+  cost of the materials for producing electrical currents on a large
+  scale by chemical action was prohibitive, while the frictional machine
+  only yielded very small currents at extremely high potentials. In the
+  dynamo, on the other hand, electrical energy in a convenient form
+  could be cheaply and easily obtained by mechanical means, and with its
+  invention the application of electricity to a wide range of commercial
+  purposes became economically possible. As a converter of energy from
+  one form to another it is only surpassed in efficiency by another
+  electrical appliance, namely, the transformer (see TRANSFORMERS). In
+  this there is merely conversion of electrical energy at a high
+  potential into electrical energy at a low potential, or vice versa,
+  but in the dynamo the mechanical energy which must be applied to
+  maintain the relative movement of magnetic field and conductor is
+  absorbed, and reappears in an electrical form. A true transformation
+  takes place, and the proportion which the rate of delivery of
+  electrical energy bears to the power absorbed, or in other words the
+  _efficiency_, is the more remarkable. The useful return or "output" at
+  the terminals of a large machine may amount to as much as 95% of the
+  mechanical energy which forms the "input." Since it needs some prime
+  mover to drive it, the dynamo has not made any direct addition to our
+  sources of energy, and does not therefore rank with the primary
+  battery or oil-engine, or even the steam-engine, all of which draw
+  their energy more immediately from nature. Yet by the aid of the
+  dynamo the power to be derived from waterfalls can be economically and
+  conveniently converted into an electrical form and brought to the
+  neighbouring factory or distant town, to be there reconverted by
+  motors into mechanical power. Over any but very short distances energy
+  is most easily transmitted when it is in an electrical form, and
+  turbine-driven dynamos are very largely and successfully employed for
+  such transmission. Thus by conducing to the utilization of water-power
+  which may previously have had but little value owing to its
+  disadvantageous situation, the dynamo may almost be said to have added
+  another to our available natural resources.
+
+The two essential parts of the dynamo, as required by its definition,
+may be illustrated by the original disk machine of Faraday. They are (1)
+the _iron magnet_, between the poles of which a magnetic field exists,
+and (2) the _electrical conductors_, represented by the rotating copper
+disk. The sector of the disk cutting the lines of the field forms part
+of a closed electric circuit, and has an E.M.F. induced in it, by reason
+of which it is no longer simply a conductor, but has become "active." In
+its more highly developed form the simple copper disk is elaborated into
+a system of many active wires or bars which form the "winding," and
+which are so interconnected as to add up their several E.M.F.'s. Since
+these active wires are usually mounted on an iron structure, which may
+be likened to the keeper or "armature" of a magnet rotating between its
+poles, the term "armature" has been extended to cover not only the iron
+core, but also the wires on it, and when there is no iron core it is
+even applied to the copper conductors themselves. In the dynamo of
+Faraday the "armature" was the rotating portion, and such is the case
+with modern continuous-current dynamos; in alternators, however, the
+magnet, or a portion of it, is more commonly rotated while the armature
+is stationary. It is in fact immaterial to the action whether the one or
+the other is moved, or both, so long as their relative motion causes the
+armature conductors to cut the magnetic flux. As to the ultimate reason
+why an E.M.F. should be thereby induced, physical science cannot as yet
+yield any surer knowledge than in the days of Faraday.[3] For the
+engineer, it suffices to know that the E.M.F. of the dynamo is due to
+the cutting of the magnetic flux by the active wires, and, further, is
+proportional to the rate at which the lines are cut.[4]
+
+[Illustration: FIG. 2.]
+
+The equation of the _electromotive force_ which is required in order to
+render this statement quantitative must contain three factors, namely,
+the density of the flux in the air-gap through which the armature
+conductors move, the active length of these wires, and the speed of
+their movement. For given values of the first and third factors and a
+single straight wire moved parallel to itself through a uniform field,
+the maximum rate of cutting is evidently obtained when the three
+directions of the lines of the conductor's length and of the relative
+motion are respectively at right angles to each other, as shown by the
+three co-ordinate axes of fig. 2. The E.M.F. of the single wire is then
+
+  E = B_gLV × 10^(-8) volts  (1)
+
+where B_g is the density of the flux within the air-gap expressed in
+C.G.S. lines per square centimetre, L is the active length of the
+conductor within the field in centimetres, and V is the velocity of
+movement in centimetres per second. Further, the direction in which the
+E.M.F. has the above maximum value is along the length of the conductor,
+its "sense" being determined by the direction of the movement[5] in
+relation to the direction of the field.
+
+The second fundamental equation of the dynamo brings to light its
+mechanical side, and rests on H.C. Oersted's discovery of the
+interaction of a magnetic field and an electric current. If a straight
+electric conductor through which a current is passing be so placed in a
+magnetic field that its length is not parallel to the direction of the
+lines of flux, it is acted on by a force which will move it, if free, in
+a definite direction relatively to the magnet; or if the conductor is
+fixed and the magnet is free, the latter will itself move in the
+opposite direction. Now in the dynamo the active wires are placed so
+that their length is at right angles to the field; hence when they are
+rotated and an electric current begins to flow under the E.M.F. which
+they induce, a mutual force at once arises between the copper conductors
+and the magnet, and the direction of this force must by Lenz's law be
+opposed to the direction of the movement. Thus as soon as the disk of
+fig. 1 is rotated and its circuit is closed, it experiences a mechanical
+pull or drag which must be overcome by the force applied to turn the
+disk. While the magnet must be firmly held so as to remain stationary,
+the armature must be of such mechanical construction that its wires can
+be forcibly driven through the magnetic field against the mutual pull.
+This law of electrodynamic action may be quantitatively stated in an
+_equation of mechanical force_, analogous to the equation (I.) of
+electromotive force, which states the law of electromagnetic induction.
+If a conductor of length L cm., carrying a current C amperes, is
+immersed in a field of uniform density B_g, and the length of the
+conductor is at right angles to the direction of the lines, it is acted
+on by a force
+
+  F = B_gLC × 10^(-1) dynes,  (2)
+
+and the direction of this force is at right angles to the conductor and
+to the field. The rate at which electrical energy is developed, when
+this force is overcome by moving the conductor as a dynamo through the
+field, is EC = B_gLVC × 10^(-8) watts, whence the equality of the
+mechanical power absorbed and the electrical power developed (as
+required by the law of the conservation of energy) is easily
+established. The whole of this power is not, however, available at the
+terminals of the machine; if R_a be the resistance of the armature in
+ohms, the passage of the current C_a through the armature conductors
+causes a drop of pressure of C_aR_a volts, and a corresponding loss of
+energy in the armature at the rate of C_a²R_a watts. As the resistance
+of the external circuit R_e is lowered, the current C = E_a/(R_e + R_a)
+is increased. The increase of the current is, however, accompanied by a
+progressive increase in the loss of energy over the armature, and as
+this is expended in heating the armature conductors, their temperature
+may rise so much as to destroy the insulating materials with which they
+are covered. Hence the temperature which the machine may be permitted to
+attain in its working is of great importance in determining its output,
+the current which forms one factor therein being primarily limited by
+the heating which it produces in the armature winding. The lower the
+resistance of the armature, the less the rise of its temperature for a
+given current flowing through it; and the reason for the almost
+universal adoption of copper as the material for the armature conductors
+is now seen to lie in its high conductivity.[6]
+
+Since the voltage of the dynamo is the second factor to which its output
+is proportional, the conditions which render the induced E.M.F. a
+maximum must evidently be reproduced as far as possible in practice, if
+the best use is to be made of a given mass of iron and copper. The first
+problem, therefore, in the construction of the dynamo is the disposition
+of the wires and field in such a manner that the three directions of
+field, length of active conductors, and movement are at right angles to
+one another, and so that the relative motion is continuous.
+Reciprocating motion, such as would be obtained by direct attachment of
+the conductors to the piston of a steam-engine, has been successfully
+employed only in the special case of an "oscillator,"[7] producing a
+small current very rapidly changing in direction. Rotary motion is
+therefore universally adopted, and with this two distinct cases arise.
+Either (A) the active length of the wire is parallel to the axis of
+rotation, or (B) it is at right angles to it.
+
+[Illustration: FIG. 3.]
+
+(A) If a conductor is rotated in the gap between the poles of a
+horse-shoe magnet, and these poles have plane parallel faces opposing
+one another as in fig. 3, not only is the density of the flux in the
+interpolar gap small, but the direction of movement is not always at
+right angles to the direction of the lines, which for the most part pass
+straight across from one opposing face to the other. When the conductor
+is midway between the poles (i.e. either at its highest or lowest
+point), it is at this instant sliding along the lines and does not cut
+them, so that its E.M.F. is zero. Taking this position as the
+starting-point, as the conductor moves round, its rate of line-cutting
+increases to a maximum when it has moved through a right angle and is
+opposite to the centre of a pole-face (as in fig. 3), from which point
+onward the rate decreases to zero when it has moved through 180°. Each
+time the conductor crosses a line drawn symmetrically through the gap
+between the poles and at right angles to the axis of rotation, the
+E.M.F. along its length is reversed in direction, since the motion
+relatively to the direction of the field is reversed. If the ends of the
+active conductor are electrically connected to two collecting rings
+fixed upon, but insulated from, the shaft, two stationary brushes bb can
+be pressed on the rings so as to make a sliding contact. An external
+circuit can then be connected to the brushes, which will form the
+"terminals" of the machine, the periodically reversed or alternating
+E.M.F. induced in the active conductor will cause an alternating current
+to flow through conductor and external circuit, and the simplest form of
+"alternator" is obtained. If the field cut by the straight conductor is
+of uniform density, and all the lines pass straight across from one
+pole-face to the other (both of which assumptions are approximately
+correct), a curve connecting the instantaneous values of the E.M.F. as
+ordinates with time or degrees of angular movement as abscissae (as
+shown at the foot of fig. 3), will, if the speed of rotation be uniform,
+be a sine curve. If, however, the conductor is mounted on an iron
+cylinder (fig. 4),[8] a sufficient margin being allowed for mechanical
+clearance between it and the poles, not only will the reluctance of the
+magnetic circuit be reduced and the total flux and its density in the
+air-gap B_g be thereby increased, but the path of the lines will become
+nearly radial, except at the "fringe" near the edges of the pole-tips;
+hence the relative directions of the movement and of the lines will be
+continuously at right angles. The shape of the E.M.F. curve will then be
+as shown in fig. 4--flat-topped, with rounded corners rapidly sloping
+down to the zero line.
+
+[Illustration: FIG. 4.]
+
+But a single wire cannot thus be made to give more than a few volts, and
+while dynamos for voltages from 5 to 10 are required for certain
+purposes, the voltages in common use range from 100 to 10,000. It is
+therefore necessary to connect a number of such wires in series, so as
+to form an "armature winding." If several similar conductors are
+arranged along the length of the iron core parallel to the first (fig.
+5), the E.M.F.'s generated in the conductors which at any moment are
+under the same pole are similarly directed, and are opposite to the
+directions of the E.M.F.'s in the conductors under the other pole (cf
+fig. 5 where the dotted and crossed ends of the wires indicate E.M.F.'s
+directed respectively towards and away from the observer). Two distinct
+methods of winding thence arise, the similarity of the E.M.F.'s under
+the same pole being taken advantage of in the first, and the opposite
+E.M.F.'s under N and S poles in the second.
+
+[Illustration: FIG. 5.]
+
+[Illustration: FIG. 6.]
+
+1. The first, or _ring_-winding, was invented by Dr Antonio Pacinotti of
+Florence[9] in 1860, and was subsequently and independently reintroduced
+in 1870[10] by the Belgian electrician, Zénobe Théophile Gramme, whence
+it is also frequently called the "Gramme" winding. By this method the
+farther end of conductor 1 (fig. 5) is joined in series to the near end
+of conductor 2; this latter lies next to it on the surface of the core
+or immediately above it, so that both are simultaneously under the same
+pole-piece. For this series connexion to be possible, the armature core
+must be a hollow cylinder, supported from the shaft on an open
+non-magnetic spider or hub, between the arms of which there is room for
+the internal wire completing the loop (fig. 6). The end of one complete
+loop or turn embracing one side of the armature core thus forms the
+starting-point for another loop, and the process can be continued if
+required to form a coil of two or more turns. In the ring armature the
+iron core serves the double purpose of conducting the lines across from
+one pole to the other, and also of shielding from the magnetic flux the
+hollow interior through which the connecting wires pass. Any lines which
+leak across the central space are cut by the internal wires, and the
+direction of cutting is such that the E.M.F. caused thereby opposes the
+E.M.F. due to the active conductors proper on the external surface. If,
+however, the section of iron in the core be correctly proportioned, the
+number of lines which cross the interior will bear but a small ratio to
+those which pass entirely through the iron, and the counter E.M.F. of
+the internal wires will become very small; they may then be regarded
+simply as connectors for joining the external active wires in series.
+
+[Illustration: FIG. 7.]
+
+2. The second or _drum_ method was used in the original "shuttle-wound"
+armatures invented by Dr Werner von Siemens in 1856, and is sometimes
+called the "Siemens" winding. The farther end of conductor 1 (fig. 5) is
+joined by a connecting wire to the farther end of another conductor 2'
+situated nearly diametrically opposite on the other side of the core and
+under the opposite pole-piece. The near end of the complete loop or turn
+is then brought across the end of the core, and can be used as the
+starting-point for another loop beginning with conductor 2, which is
+situated by the side of the first conductor. The iron core may now be
+solid from the surface to the shaft, since no connecting wires are
+brought through the centre, and each loop embraces the entire armature
+core (fig. 7). By the formation of two loops in the ring armature and of
+the single loop in the drum armature, two active wires are placed in
+series; the curves of instantaneous E.M.F. are therefore similar in
+shape to that of the single wire (fig. 4), but with their ordinates
+raised throughout to double their former height, as shown at the foot of
+fig. 6.
+
+Next, if the free ends of either the ring or drum loops, instead of
+being connected to two collecting rings, are attached to the two halves
+of a split-ring insulated from the shaft (as shown in fig. 7 in
+connexion with a drum armature), and the stationary brushes are so set
+relatively to the loops that they pass over from the one half of the
+split-ring to the other half at the moment when the loops are passing
+the centre of the interpolar gap, and so are giving little or no E.M.F.,
+each brush will always remain either positive or negative. The current
+in the external circuit attached to the brushes will then have a
+constant direction, although the E.M.F. in the active wires still
+remains alternating; the curve of E.M.F. obtained at the brushes is thus
+(as in fig. 7) entirely above the zero line. The first dynamo of H.
+Pixii,[11] which immediately followed Faraday's discovery, gave an
+alternating current, but in 1832[12] the alternator was converted into a
+machine giving a _unidirected current_ by the substitution of a
+rudimentary "commutator" in place of mercury collecting cups.
+
+(B) So far the length of the active wires has been parallel to the axis
+of rotation, but they may equally well be arranged perpendicularly
+thereto. The poles will then have plane faces and the active wires will
+be disposed with their length approximately radial to the axis of the
+shaft. In order to add their E.M.F.'s in series, two types of winding
+may be employed, which are precisely analogous in principle to the ring
+and drum windings under arrangement (A).
+
+3. The _discoidal_ or flat-ring armature is equivalent to a ring of
+which the radial depth greatly exceeds the length, with the poles
+presented to one side of the ring instead of embracing its cylindrical
+surface. A similar set of poles is also presented to the opposite side
+of the ring, like poles being opposite to one another, so that in effect
+each polar surface is divided into two halves, and the groups of lines
+from each side bifurcate and pass circumferentially through the armature
+core to issue into the adjacent poles of opposite sign.
+
+4. In the _disk_ machine, no iron core is necessary for the armature,
+the two opposite poles of unlike sign being brought close together,
+leaving but a short path for the lines in the air-gap through which the
+active wires are rotated.
+
+If the above elementary dynamos are compared with fig. 1, it will be
+found that they all possess a distinctive feature which is not present
+in the original disk machine of Faraday. In the four types of machine
+above described each active wire in each revolution first cuts the group
+of lines forming a field in one direction, and then cuts the same lines
+again in the opposite direction relatively to the sense of the lines, so
+that along the length of the wire the E.M.F. alternates in direction.
+But in the dynamo of fig. 1 the sector of the copper disk which is at
+any moment moving through the magnetic field and which forms the single
+active element is always cutting the lines in the same manner, so that
+the E.M.F. generated along its radial length is continuous and unchanged
+in direction. This radical distinction differentiates the two classes of
+_heteropolar_ and _homopolar_ dynamos, Faraday's disk machine of fig. 1
+being the type of the latter class. In it the active element may be
+arranged either parallel or at right angles to the axis of rotation;
+but in both cases, in order to increase the E.M.F. by placing two or
+more elements in series, it becomes necessary either (1) to employ some
+form of sliding contact by which the current may be collected from the
+end of one active element and passed round a connecting wire into the
+next element without again cutting the field in the reverse direction,
+or (2) to form on the armature a loop of which each side is alternately
+active and inactive. The first method limits the possibilities of the
+homopolar machine so greatly when large currents and high voltages are
+required that it is now only used in rare instances, as e.g.
+occasionally in dynamos driven by steam-turbines which have a very high
+speed of rotation. The second alternative may be carried into effect
+with any of the four methods of armature winding, but is practically
+confined to the drum and disk types. In its drum form the field is
+divided into two or more projecting poles, all of the same sign, with
+intervening neutral spaces of equal width, and the span of the loop in
+the direction of rotation is at least equal to the width of a polar
+projection, as in fig. 8, where two polar projections are shown. Each
+side of the loop then plays a dual part; it first cuts the lines of one
+polar projection and generates an E.M.F., and next becomes an inactive
+connecting wire, while the action is taken up by the opposite side of
+the loop which has previously served as a connector but now cuts the
+lines of the next polar projection. The E.M.F. is thus always in the
+same direction along the side which is at any moment active, but
+alternates round the loop as a whole, and the distinctive peculiarity of
+the homopolar machine, so soon as any form of "winding" is introduced
+into its armature, is lost. It results that the homopolar principle,
+which would prima facie appear specially suitable for the generation of
+a unidirectional E.M.F. and continuous current, can seldom be used for
+this purpose and is practically confined to alternators. It may
+therefore be said that in almost all dynamos, whether they supply an
+alternating or a continuous current in the external circuit, the E.M.F.
+and current in the armature are alternating.
+
+[Illustration: FIG. 8.]
+
+Ring winding was largely employed in early continuous-current dynamos
+and also in the alternators of Gramme and H. Wilde, and later of Auguste
+de Méritens. Disk winding was also successfully introduced for
+alternators, as in the magneto-machines of Nollet (1849) and the
+alternators of Wilde (1866) and Siemens (1878), and its use was
+continued in the machines of W.M. Mordey and S.Z. Ferranti. But although
+the ring, discoidal-ring and disk methods of winding deserve mention
+from their historical importance, experience has shown that drum winding
+possesses a marked superiority for both electrical and manufacturing
+reasons; the three former methods have in fact been practically
+discarded in its favour, so that the drum method will hereafter alone be
+considered.
+
+The drum coil, composed of several loops wound side by side, may
+therefore be regarded as the constituent active element out of which the
+armature winding of the modern dynamo is developed. Its application to
+the multipolar machine is easily followed from fig. 9, which illustrates
+the heteropolar type of dynamo. The span of the loops, which is nearly
+180° or across the diameter of the two-pole machine, is reduced
+approximately to 90° in the four-pole or to 60° in the six-pole machine
+and so on, the curvature of the coil becoming gradually less as the
+number of poles is increased. The passage of a coil through two magnetic
+fields of opposite direction yields a complete wave of E.M.F., such as
+is shown in fig. 6, and the time in seconds taken to pass through such a
+complete cycle is the "period" of the alternating E.M.F. The number of
+complete periods through which the E.M.F. of the coil passes per second
+is called the "periodicity" or "frequency" of the machine. In the
+bipolar machine this is equal to the number of revolutions per second,
+and in the multipolar machine it is equal to the number of pairs of
+fields through which the coil passes in one second; hence in general the
+periodicity is pN/60, where N = the number of revolutions per minute and
+p = the number of pairs of poles, and this holds true of the E.M.F. and
+current round the coil, even though the E.M.F. and current furnished to
+the external circuit may be rendered unidirectional or continuous. The
+only difference on this point is that in the continuous-current machine
+the poles are usually fewer than in the alternator, and the periodicity
+is correspondingly lower. Thus in the former case the number of poles
+ranges from 2 to 12 and the usual frequencies from 5 to 20; but with
+alternators the frequencies in commercial use range from 25 to 120, and
+in large machines driven by slow-speed engines the number of poles may
+even be as high as 96.
+
+[Illustration: FIG. 9.
+
+I. Smooth. II. Toothed.]
+
+[Illustration: FIG. 10.]
+
+The drum coil may be applied either to the external surface of a
+rotating armature, the field-magnet being external and stationary (fig.
+9), or to the internal surface of a stationary armature (fig. 10), the
+field-magnet being internal and rotating. While the former combination
+is universally adopted in the continuous-current dynamo, the latter is
+more usual in the modern alternator. In either case the iron armature
+core must be "laminated"; the passage of the lines of the field across
+its surface sets up E.M.F.'s which are in opposite directions under
+poles of opposite sign, so that if the core were a solid mass a
+current-sheet would flow along its surface opposite to a pole, and
+complete its circuit by passing through the deeper layers of metal or by
+returning in a sheet under a pole of opposite sign. Such "eddy-currents"
+can be practically avoided by dividing the metal core into laminations
+at right angles to the length of the active wires which are themselves
+arranged to secure the greatest rate of line-cutting and maximum E.M.F.
+The production of the eddy-current E.M.F. is not thereby prevented, but
+the paths of the eddy-currents are so broken up that the comparatively
+high resistance with which they meet reduces their amount very greatly.
+The laminae must be lightly insulated from one another, right up to
+their edges, so that the E.M.F.'s which still act across their thickness
+will not be added up along the length of the core, but will only produce
+extremely small currents circulating through the interior of the
+separate laminations. Each thin iron plate is either coated with an
+insulating varnish or has one of its sides covered with a sheet of very
+thin paper; the thickness of the laminae is usually about one-fortieth
+of an inch, and if this is not exceeded the rate at which energy is
+dissipated by eddy-currents in the core is so far reduced that it does
+not seriously impair the efficiency of the machine.
+
+Lastly, the drum coils may be either attached to the surface of a smooth
+armature core (fig. 9, I.), or may be wound through holes formed close
+to the periphery of the core, or may be embedded in the slots between
+projecting iron teeth (figs. 9 [II.] and 10). Originally employed by
+Antonio Pacinotti in connexion with ring winding, the toothed armature
+was after some considerable use largely discarded in favour of the
+smooth core; it has, however, been reintroduced with a fuller
+understanding of the special precautions necessitated in its design, and
+it is now so commonly used that it may be said to have superseded the
+smooth-surface armature.
+
+  Not only does the toothed armature reduce the length of the air-gap to
+  the minimum permitted by mechanical and magnetic considerations, and
+  furnish better mechanical protection to the armature coils, but it
+  also ensures the positive holding of the active wires against the
+  mechanical drag which they experience as they pass through the
+  magnetic field. Further, the active wires in the toothed armature are
+  relieved of a large proportion of this mechanical drag, which is
+  transferred to the iron teeth. The lines of the field, after passing
+  through the air-gap proper, divide between the teeth and the slots in
+  proportion to their relative permeances. Hence at any moment the
+  active wires are situated in a weak field, and for a given armature
+  current the force on them is only proportional to this weak field.
+  This important result is connected with the fact that when the
+  armature is giving current the distribution of the lines over the face
+  of each tooth is distorted, so that they become denser on the
+  "trailing" side than on the "leading" side;[13] the effect of the
+  non-uniform distribution acting on all the teeth is to produce a
+  magnetic drag on the armature core proportional to the current passing
+  through the wires, so that the total resisting force remains the same
+  as if the armature had a smooth core. The amount by which the stress
+  on the active wires is reduced entirely depends upon the degree to
+  which the teeth are saturated, but, since the relative permeability of
+  iron even at a flux density of 20,000 lines per sq. cm. is to that of
+  air approximately as 33:1, the embedded wires are very largely
+  relieved of the driving stress. An additional gain is that solid bars
+  of much greater width can be used in the toothed armature than on a
+  smooth core without appreciable loss from eddy-currents within their
+  mass.
+
+  A disadvantage of the slotted core is, however, that it usually
+  necessitates the lamination of the pole-pieces. If the top of the slot
+  is open, and its width of opening is considerably greater than the
+  length of the air-gap from the iron of the pole-face to the surface of
+  the teeth, the lines become unequally distributed not only at the
+  surface of the teeth, but also at the face of the pole-pieces; and
+  this massing of the lines into bands causes the density at the
+  pole-face to be rhythmically varied as the teeth pass under it. No
+  such variation can take place in a solid mass of metal without the
+  production of eddy-currents within it; hence if the width of the
+  slot-opening is equal to or exceeds twice the length of the single
+  air-gap, lamination of the pole-pieces in the same plane as that of
+  the armature core becomes advisable.
+
+  If the wires are threaded through holes or tunnels pierced close to
+  the periphery of the core, the same advantages are gained as with open
+  slots, and lamination of the pole-pieces is rendered unnecessary. But
+  on the other hand, the process of winding becomes laborious and
+  expensive, while the increase in the inductance of the coils owing to
+  their being surrounded by a closed iron circuit is prejudicial to
+  sparkless commutation in the continuous-current dynamo and to the
+  regulation of the voltage of the alternator. A compromise is found in
+  the half-closed slot, which is not uncommon in alternators, although
+  the open slot is more usual in continuous-current dynamos.
+
+With the addition of more turns to the elementary drum loop or of
+several complete coils, new questions arise, and in connexion therewith
+the two great classes of machines, viz. alternators and
+continuous-current dynamos, which have above been treated side by side,
+diverge considerably, so that they are best considered separately. The
+electromotive-force equation of the alternator will be first deduced,
+and subsequently that of the continuous-current machine.
+
+[Illustration: FIG. 11.]
+
+Corresponding to the number of pairs of poles in the multipolar
+alternator, it is evident that there may also be an equal number of
+coils as shown diagrammatically in fig. 11. The additional coils, being
+similarly situated in respect to other pairs of poles, will exactly
+reproduce the E.M.F. of the original coil in phase and magnitude, so
+that when they are connected in series the total E.M.F. will be
+proportional to the number of coils in series; or if they are connected
+in parallel, while not adding to the E.M.F., they will proportionately
+increase the current-carrying capacity of the combination. But within
+each coil the addition of more loops will not cause an equal increase in
+the total E.M.F., unless the phases of the component E.M.F.'s due to the
+several turns are identical, and on this account it becomes necessary to
+consider the effect of the width of the coil-side.
+
+[Illustration: FIG. 12.]
+
+If the additional loops are wound within the same slots as the original
+loop, the winding is "concentrated," and each turn will then add the
+same E.M.F. But if the coil-side is divided between two or more slots,
+the phase of the E.M.F. yielded by the wires in one slot being different
+from that of the wires in another neighbouring slot, the sum of all the
+E.M.F.'s will be less than the E.M.F. of one component loop multiplied
+by the number of loops or turns in the coil. The percentage reduction in
+the E.M.F. will depend upon the number of the slots in a coil-side and
+their distance apart, i.e. on the virtual width of the coil-side
+expressed as a fraction of the "pole-pitch" or the distance measured
+along the pitch-line from the centre of one pole to the centre of a
+neighbouring pole of opposite sign (fig. 12). The winding is now to be
+regarded as "grouped," since a small number of distinct phases
+corresponding to the groups within the two, three or four slots have to
+be compounded together. As the number of slots per coil-side is
+increased, an approach is gradually made to the case of "uniform
+distribution," such as would obtain in a smooth-core armature in which
+the turns of the coil are wound closely side by side. Thus in the
+six-turn coil of fig. 12 A, which represents the development of a
+two-pole armature when the core is cut down to the shaft and opened out
+flat, there are in effect six phases compounded together, each of which
+differs but little from that of its next neighbour. With numerous wires
+lying still closer together a large number of phases are compounded
+until the distribution becomes practically uniform; the decrease in the
+E.M.F., as compared with that of a single turn multiplied by the number
+in series, is then immediately dependent upon the width of the coil-side
+relatively to the pole-pitch.
+
+[Illustration: FIG. 13.]
+
+If the width of the inner loop of fig. 12 A is less than that of the
+pole-face, its two sides will for some portion of each period be moving
+under the same pole, and "differential action" results, the net E.M.F.
+being only that due to the difference between the E.M.F.'s of the two
+sides. The loop of smallest width must therefore exceed the width of
+pole-face, if direct differential action is to be avoided. The same
+consideration also determines the width of the outer loop; if this be
+deducted from twice the pole-pitch, the difference should not be less
+than the width of the pole-face, so that, e.g., in a bipolar machine the
+outer loop may stand to the S. pole exactly as the inner loop stands to
+the N. pole (fig. 13). In other words, the width of the coil-side must
+not exceed the width of the interpolar gap between two fields. Evidently
+then if the ratio of the pole-width to the pole-pitch approaches unity,
+the width of the coil-side must be very small, and vice versa. A
+compromise between these conflicting considerations is found if the pole
+is made not much more than half the pole-pitch, and the width of the
+coil-side is similarly about half the pole-pitch and therefore equal in
+width to the pole (fig. 13). A single large coil, such as that of fig.
+12 A, can, however, equally well be divided into two halves by taking
+the end-connexions of one half of the turns round the opposite side of
+the shaft (fig. 12 B), as indeed has already been done in fig. 13. Each
+sheaf or band of active wires corresponding to a pole is thereby
+unaffected, but the advantages are gained that the axial length of the
+end-connexions is halved, and that they have less inductance. Thus if in
+fig. 11 there are four turns per coil, fig. 14 is electrically
+equivalent to it (save that the coils are here shown divided into two
+parallel paths, each carrying half the total current). When the large
+coils are divided as above described, it results that there are as many
+coils as there are poles, the outer loop of the small coil having a
+width equal to the pole-pitch, and the inner a width equal to the
+pole-face.
+
+[Illustration: FIG. 14.]
+
+Such is the form which the "single-phase alternator" takes, but since
+only one-half of the armature core is now covered with winding, an
+entirely distinct but similar set of coils may be wound to form a second
+armature circuit between the coils of the first circuit. The phase of
+this second circuit will differ by 90° or a quarter of a period from
+that of the first, and it may either be used to feed an entirely
+separate external circuit possibly at a different pressure or, if it be
+composed of the same number of turns and therefore gives the same
+voltage, it may be interconnected with the first circuit to form a
+"quarter-phase alternator," as will be more fully described later. By an
+extension of the same process, if the width of each side of a coil is
+reduced to one-sixth of the pole-pitch, three armature circuits can be
+wound on the same core, and a "three-phase alternator," giving waves of
+E.M.F. differing in phase by 120°, is obtained.
+
+  The fundamental "electromotive-force equation" of the heteropolar
+  alternator can now be given a more definite form. Let Z_a be the
+  number of C. G. S. lines or the total flux, which issuing from any
+  one pole flows through the armature core, to leave it by another pole
+  of opposite sign. Since each active wire cuts these lines, first as
+  they enter the armature core and then as they emerge from it to enter
+  another pole, the total number of lines cut in one revolution by any
+  one active wire is 2pZ_a. The time in seconds taken by one revolution
+  is 60/N. The average E.M.F. induced in each active wire in one
+  revolution being proportional to the number of lines cut divided by
+  the time taken to cut them is therefore 2Z_a(pN/60) × 10^(-8) volts.
+  The active wires which are in series and form one distinct phase may
+  be divided into as many bands as there are poles; let each such band
+  contain t active wires, which as before explained may either form one
+  side of a single large coil or the adjacent sides of two coils when
+  the large coil is divided into two halves. Since the wires are joined
+  up into loops, two bands are best considered together, which with
+  either arrangement yield in effect a single coil of t turns. The
+  average E.M.F.'s of all the wires in the two bands when added together
+  will therefore be 4Z_a(pN/60)t × 10^(-8). But unless each band is
+  concentrated within a single slot, there must be some differential
+  action as they cross the neutral line between the poles, so that the
+  last expression is virtually the _gross_ average E.M.F. of the loops
+  on the assumption that the component E.M.F.'s always act in agreement
+  round the coil and do not at times partially neutralize one another.
+  The _net_ average E.M.F. of the coil as a whole, or the arithmetical
+  mean of all the instantaneous values of a half-wave of the actual
+  E.M.F. curve, is therefore reduced to an extent depending upon the
+  amount of differential action and so upon the width of the coil-side
+  when this is not concentrated. Let k' = the coefficient by which the
+  gross average E.M.F. must be multiplied to give the net average
+  E.M.F.; then k' may be called the "width-factor," and will have some
+  value less than unity when the wires of each band are spread over a
+  number of slots. The net average E.M.F. of the two bands corresponding
+  to a pair of poles is thus e_(av) = 4k'Z_a(pN/60)t × 10^(-8).
+
+  The shape of the curve of instantaneous E.M.F. of the coil must
+  further be taken into account. The "effective" value of an alternating
+  E.M.F. is equal to the square root of the mean square of its
+  instantaneous values, since this is the value of the equivalent
+  unidirectional and unvarying E.M.F., which when applied to a given
+  resistance develops energy at the same rate as the alternating E.M.F.,
+  when the effect of the latter is averaged over one or any whole number
+  of periods. Let k" = the ratio of the square root of the mean square
+  to the average E.M.F. of the coil, i.e. = effective E.M.F./average
+  E.M.F. Since it depends upon the shape of the E.M.F. curve, k" is also
+  known as the "form-factor"; thus if the length of gap between
+  pole-face and armature core and the spacing of the wires were so
+  graduated as to give a curve of E.M.F. varying after a sine law, the
+  form-factor would have the particular value of [pi]/2[root]2 = 1.11,
+  and to this condition practical alternators more or less conform. The
+  effective E.M.F. of the two bands corresponding to a pair of poles is
+  thus e_(eff) = 4k'k"Z_a(pN/60)t × 10^(-8).
+
+  In any one phase there are p pairs of bands, and these may be divided
+  into q parallel paths, where q is one or any whole number of which p
+  is a multiple. The effective E.M.F. of a complete phase is therefore
+  pe{eff}/q. Lastly, if m = the number of phases into which the armature
+  winding is divided, and [tau] = the total number of active wires on
+  the armature counted all round its periphery, t = [tau]/2pm, and the
+  effective E.M.F. per phase is E_a = 2k'k"Z_a(pN[tau]/60mq) × 10^(-8).
+
+  The two factors k' and k" may be united into one coefficient, and the
+  equation then takes its final form
+
+    E_a = 2KZ_a(pN[tau]/60mq) × 10^(-8) volts  (1a)
+
+  In the alternator q is most commonly 1, and there is only one circuit
+  per phase; finally the value of K or the product of the width-factor
+  and the form-factor usually falls between the limits of 1 and 1.25.
+
+We have next to consider the effect of the addition of more armature
+loops in the case of dynamos which give a unidirectional E.M.F. in
+virtue of their split-ring collecting device, i.e. of the type shown in
+fig. 7 with drum armature or its equivalent ring form. As before, if the
+additional loops are wound in continuation of the first as one coil
+connected to a single split-ring, this coil must be more or less
+concentrated into a narrow band; since if the width becomes nearly equal
+to or exceeds the width of the interpolar gap, the two edges of the
+coil-side will just as in the alternator act differentially against one
+another during part of each revolution. The drum winding with a single
+coil thus gives an armature of the H- or "shuttle" form invented by Dr
+Werner von Siemens. Although the E.M.F. of such an arrangement may have
+a much higher maximum value than that of the curve of fig. 7 for a
+single loop, yet it still periodically varies during each revolution and
+so gives a pulsating current, which is for most practical uses
+unsuitable. But such pulsation might be largely reduced if, for example,
+a second coil were placed at right angles to the original coil and the
+two were connected in series; the crests of the wave of E.M.F. of the
+second coil will then coincide with the hollows of the first wave,
+and although the maximum of the resultant curve of E.M.F. may be no
+higher its fluctuations will be greatly decreased. A spacial
+displacement of the new coils along the pole-pitch, somewhat as in a
+polyphase machine, thus suggests itself, and the process may be carried
+still further by increasing the number of equally spaced coils, provided
+that they can be connected in series and yet can have their connexion
+with the external circuit reversed as they pass the neutral line between
+the poles.
+
+[Illustration: FIG. 15.]
+
+[Illustration: FIG. 16.]
+
+Given two coils at right angles and with their split-rings displaced
+through a corresponding angle of 90°, they may be connected in series by
+joining one brush to the opposite brush of the second coil, the external
+circuit being applied to the two remaining brushes.[14] The same
+arrangement may again be repeated with another pair of coils in parallel
+with the first, and we thus obtain fig. 15 with four split-rings, their
+connexions to the loops being marked by corresponding numerals; the four
+coils will give the same E.M.F. as the two, but they will be jointly
+capable of carrying twice the current, owing to their division into two
+parallel circuits. Now in place of the four split-rings may be employed
+the greatly simplified four-segment structure shown in fig. 16, which
+serves precisely the same purpose as the four split-rings but only
+requires two instead of eight brushes. The effect of joining brush 2 in
+fig. 15 across to brush 3, brush 4 to brush 5, 5 to 6, &c., has
+virtually been to connect the end of coil A with the beginning of coil
+B, and the end of coil B with the beginning of coil A', and so on, until
+they form a continuous closed helix. Each sector of fig. 16 will
+therefore replace two halves of a pair of adjacent split-rings, if the
+end and beginning of a pair of adjacent coils are connected to it in a
+regular order of sequence. The four sectors are insulated from one
+another and from the shaft, and the whole structure is known as the
+"commutator,"[15] its function being not simply to collect the current
+but also to commute its direction in any coil as it passes the
+interpolar gap. The principle of the "closed-coil continuous-current
+armature" is thus reached, in which there are at least two parallel
+circuits from brush to brush, and from which a practically steady
+current can be obtained. Each coil is successively short-circuited, as a
+brush bridges over the insulation between the two sectors which
+terminate it; and the brushes must be so set that the period of
+short-circuit takes place when the coil is generating little or no
+E.M.F., i.e. when it is moving through the zone between the pole-tips.
+The effect of the four coils in reducing the percentage fluctuation of
+the E.M.F. is very marked, as shown at the foot of fig. 15 (where the
+upper curve is the resultant obtained by adding together the separate
+curves of coils A and B), and the levelling process may evidently be
+carried still further by the insertion of more coils and more
+corresponding sectors in the commutator, until the whole armature is
+covered with winding. For example, figs. 17 and 18 show a ring and a
+drum armature, each with eight coils and eight commutator sectors; their
+resultant curve, on the assumption that a single active wire gives the
+flat-topped curve of fig. 4, will be the upper wavy line of E.M.F.
+obtained by adding together two of the resultant curves of fig. 15, with
+a relative displacement of 45°. The amount of fluctuation for a given
+number of commutator sectors depends upon the shape of the curve of
+E.M.F. yielded by the separate small sections of the armature winding;
+the greater the polar arc, the less the fluctuation. In practice, with a
+polar arc equal to about 0.75 of the pitch, any number of sectors over
+32 per pair of poles yields an E.M.F. which is sensibly constant
+throughout one or any number of revolutions.
+
+[Illustration: FIG. 17.]
+
+[Illustration: FIG. 18.]
+
+  The fundamental electro-motive-force equation of the
+  continuous-current heteropolar machine is easily obtained by analogy
+  from that of the alternator. The gross average E.W.F. from the two
+  sides of a drum loop without reference to its direction is as before
+  4Z_a(pN/60) × 10^(-8) volts. But for two reasons its net average
+  E.M.F. may be less; the span of the loop may be less than the
+  pole-pitch, so that even when the brushes are so set that the position
+  of short-circuit falls on the line where the field changes its
+  direction, the two sides of the loop for some little time act against
+  each other; or, secondly, even if the span of the loop be equal to the
+  pole-pitch, the brushes may be so set that the reversal of the
+  direction of its induced E.M.F. does not coincide with reversal of the
+  current by the passage of the coil under the brushes. The net average
+  E.M.F. of the loop is therefore proportional to the algebraic sum of
+  the lines which it cuts in passing from one brush to another, and this
+  is equal to the net amount of the flux which is included within the
+  loop when situated in the position of short-circuit under a brush. The
+  amount of this flux may be expressed as k'Z_a where k' is some
+  coefficient, less than unity if the span of the coil be less than the
+  pole-pitch, and also varying with the position of the brushes. The net
+  average E.M.F. of the loop is therefore
+
+    4k'Z_a(pN/60) × 10^(-8).
+
+  In practice the number of sections of the armature winding is so large
+  and their distribution round the armature periphery is so uniform,
+  that the sum total of the instantaneous E.M.F.'s of the several
+  sections which are in series becomes at any moment equal to the net
+  average E.M.F. of one loop multiplied by the number which are in
+  series. If the winding is divided into q parallel circuits, the number
+  of loops in series is [tau]/2q, so that the total E.M.F. is E_a =
+  2(k'/q)Z_a(pN/60)[tau] × 10^(-8) volts. Thus as compared with the
+  alternator not only is there no division of the winding into separate
+  phases, but the form-factor k' disappears, since the effective and
+  average E.M.F.'s are the same. Further whereas in the alternator q may
+  = 1, in the continuous-current closed-coil armature there can never be
+  less than two circuits in parallel from brush to brush, and if more,
+  their number must always be a multiple of two, so that q can never be
+  less than two and must always be an even number. Lastly, the factor k'
+  is usually so closely equal to 1, that the simplified equation may in
+  practice be adopted, viz.
+
+    E_a = (2/q)(ZpN/60)[tau] × 10^(-8) volts  (1b)
+
+  The fundamental equation of the electromotive force of the dynamo in
+  its fully developed forms (1 a) (and 1 b) may be compared with its
+  previous simple statement (1.). The three variable terms still find
+  their equivalents, but are differently expressed, the density B_g
+  being replaced by the total flux of one field Z_a, the length L of the
+  single active wire by the total number of such wires [tau], and the
+  velocity of movement V by the number of revolutions per second. Even
+  when the speed is fixed, an endless number of changes may be rung by
+  altering the relative values of the remaining two factors; and in
+  successful practice these may be varied between fairly wide limits
+  without detriment to the working or economy of the machine. While it
+  may be said that the equation of the E.M.F. was implicitly known from
+  Faraday's time onwards, the difficulty under which designers laboured
+  in early days was the problem of choosing the correct relation of Z_a
+  or [tau] for the required output; this, again, was due chiefly to the
+  difficulty of predetermining the total flux before the machine was
+  constructed. The general error lay in employing too weak a field and
+  too many turns on the armature, and credit must here be given to the
+  American inventors, E. Weston and T.A. Edison, for their early
+  appreciation of the superiority in practical working of the drum
+  armature, with comparatively few active wires rotating in a strong
+  field.
+
+
+  The armature core.
+
+_Continuous-current Dynamos._--On passing to the separate consideration
+of alternators and continuous-current dynamos, the chief constructive
+features of the latter will first be taken in greater detail. As already
+stated in the continuous-current dynamo the armature is usually the
+rotating portion, and the necessity of laminating its core has been
+generally described. The thin iron stampings employed to build up the
+core take the form of circular washers or "disks," which in small
+machines are strung directly on the shaft; in larger multipolar
+machines, in which the required radial depth of iron is small relatively
+to the diameter, a central cast iron hub supports the disks. Since the
+driving force is transmitted through the shaft to the disks, they must
+in the former case be securely fixed by keys sunk into the shaft; when a
+central hub is employed (fig. 19) it is keyed to the shaft, and its
+projecting arms engage in notches stamped on the inner circumference of
+the disks, or the latter have dovetailed projections fitting into the
+arms. The disks are then tightly compressed and clamped between stout
+end-plates so as to form a nearly solid iron cylinder of axial length
+slightly exceeding the corresponding dimension of the poles. If the
+armature is more than 4 ft. in diameter, the disks become too large to
+be conveniently handled in one piece, and are therefore made in
+segments, which are built up so as to break joint alternately. Prior to
+assemblage, the external circumference of each disk is notched in a
+stamping machine with the required number of slots to receive the
+armature coils, and the longitudinal grooves thereby formed in the
+finished core only require to have their sharp edges smoothed off so
+that there may be no risk of injury to the insulation of the coils.
+
+[Illustration: FIG. 19.]
+
+
+  Armature winding.
+
+With open slots either the armature coils may be encased with wrappings
+of oiled linen, varnished paper and thin flexible micanite sheeting in
+order to insulate them electrically from the iron slots in which they
+are afterwards embedded; or the slots may be themselves lined with
+moulded troughs of micanite, &c., for the reception of the armature
+coils, the latter method being necessary with half-closed slots.
+According to the nature of the coils armatures may be divided into the
+two classes of coil-wound and bar-wound. In the former class, round
+copper wire, double-cotton covered, is employed, and the coils are
+either wound by hand directly on to the armature core, or are shaped on
+formers prior to being inserted in the armature slots. Hand-winding is
+now only employed in very small bipolar machines, the process being
+expensive and accompanied by the disadvantage that if one section
+requires to be repaired, the whole armature usually has to be dismantled
+and re-wound. Former-wound coils are, on the other hand, economical in
+labour, perfectly symmetrical and interchangeable, and can be thoroughly
+insulated before they are placed in the slots. The shapers employed in
+the forming process are very various, but are usually arranged to give
+to the finished coil a lozenge shape, the two straight active sides
+which fit into the straight slots being joined by V-shaped ends; at each
+apex of the coil the wire is given a twist, so that the two sides fall
+into different levels, an upper and a lower, corresponding to the two
+layers which the coil-sides form on the finished armature. Rectangular
+wire of comparatively small section may be similarly treated, and if
+only one loop is required per section, wide and thin strip can be bent
+into a complete loop, so that the only soldered joints are those at the
+commutator end where the loops are interconnected. But finally with
+massive rectangular conductors, the transition must be made to
+bar-winding, in which each bar is a half-loop, insulated by being taped
+after it has been bent to the required shape; the separate bars are
+arranged on the armature in two layers, and their ends are soldered
+together subsequently to form loops. As a general rule, whether bars or
+former-wound coils are employed, the armature is barrel-wound, i.e. the
+end-connexions project outwards from the slots with but little change of
+level, so that they form a cylindrical mass supported on projections
+from the end-plates of the core (fig. 19); but, in certain cases, the
+end-connexions are bent downwards at right angles to the shaft, and they
+may then consist of separate strips of copper bent to a so-called
+butterfly or evolute shape.
+
+After the coils or loops have been assembled in the slots on the
+armature core, and the commutator has been fixed in place on the shaft,
+the soldering of the ends of the coils proceeds, by which at once the
+union of the end of one coil with the beginning of the next, and also
+their connexion to the commutator sectors, is effected, and in this lies
+the essential part of armature winding.
+
+[Illustration: FIG. 20.
+
+Lap-loops]
+
+
+    Lap-winding.
+
+  The development of the modern drum armature, with its numerous coils
+  connected in orderly sequence into a symmetrical winding, as
+  contrasted with the earlier Siemens armatures, was initiated by F. von
+  Hefner Alteneck (1871), and the laws governing the interconnexion of
+  the coils have now been elaborated into a definite system of winding
+  formulae. Whatever the number of wires or bars in each side of a coil,
+  i.e. whether it consist of a single loop or of many turns, the final
+  connexions of its free ends are not thereby affected, and it may be
+  mentally replaced by a single loop with two active inducing sides. The
+  coil-sides in their final position are thus to be regarded as separate
+  primary elements, even in number, and distributed uniformly round the
+  armature periphery or divided into small, equally spaced groups by
+  being located within the slots of a toothed armature. Attention must
+  then be directed simply to the span of the back connexion between the
+  elements at the end of the armature further from the commutator, and
+  to the span of the front connexion by which the last turn of a coil is
+  finally connected to the first turn of the next in sequence, precisely
+  as if each coil of many turns were reduced to a single loop. In order
+  to avoid direct differential action, the span of the back connexion
+  which fixes the width of the coil must exceed the width of the
+  pole-face, and should not be far different from the pole-pitch; it is
+  usually a little less than the pole-pitch. Taking any one element as
+  No. 1 in fig. 20, where for simplicity a smooth-core bipolar armature
+  is shown, the number of winding-spaces, each to be occupied by an
+  element, which must be counted off in order to find the position of
+  the next element in series, is called the "pitch" of the
+  end-connexion, front or back, as the case may be. Thus the back pitch
+  of the winding as marked by the dotted line in fig. 20 is 7, the
+  second side of the first loop being the element numbered 1 + 7 = 8. In
+  forming the front end-connexion which completes the loop and joins it
+  to the next in succession, two possible cases present themselves. By
+  the first, or "lap-winding," the front end-connexion is brought
+  backwards, and passing on its way to a junction with a commutator
+  sector is led to a third element lying within the two sides of the
+  first loop, i.e. the second loop starts with the element, No. 3, lying
+  next but one to the starting-point of the first loop. The winding
+  therefore returns backwards on itself to form each front end, but as a
+  whole it works continually forwards round the armature, until it
+  finally "re-enters," after every element has been traversed. The
+  development of the completed winding on a flat surface shows that it
+  takes the form of a number of partially overlapping loops, whence its
+  name originates. The firm-line portion of fig. 21 gives the
+  development of an armature similar to that of fig. 18 when cut through
+  at the point marked X and opened out; two of the overlapping loops are
+  marked thereon in heavy lines. The multipolar lap-wound armature is
+  obtained by simply repeating the bipolar winding p times, as indicated
+  by the dotted additions of fig. 21 which convert it from a two-pole to
+  a four-pole machine. The characteristic feature of the lap-wound
+  armature is that there are as many parallel paths from brush to brush,
+  and as many points at which the current must be collected, as there
+  are poles. As the bipolar closed-coil continuous-current armature has
+  been shown to consist in reality of two circuits in parallel, each
+  giving the same E.M.F. and carrying half the total current, so the
+  multipolar lap-wound drum consists of p pairs of parallel paths, each
+  giving the same E.M.F. and carrying 1/2p of the total current. Thus in
+  equation 1.b we have q = 2p, and the special form which the _E.M.F.
+  equation of the lap-wound armature_ takes is E_[alpha] = Z_a
+  (N/60)[tau] × 10^(-8) volts. All the brushes which are of the same
+  sign must be connected together in order to collect the total armature
+  current. The several brush-sets of the multipolar lap-wound machine
+  may again be reduced to two by "cross-connexion" of sectors situated
+  360°/p apart, but this is seldom done, since the commutator must then
+  be lengthened p times in order to obtain the necessary brush
+  contact-surface for the collection of the entire current.
+
+  [Illustration: FIG. 21.]
+
+  [Illustration: FIG. 22.
+
+  Wave-loops]
+
+  [Illustration: FIG. 23.]
+
+
+    Wave-winding.
+
+  But for many purposes, especially where the voltage is high and the
+  current small, it is advantageous to add together the inductive effect
+  of the several poles of the multipolar machine by throwing the E.M.F's
+  of half the total number of elements into series, the number of
+  parallel circuits being conversely again reduced to two. This is
+  effected by the second method of winding the closed-coil continuous
+  current drum, which is known as "wave-winding." The front pitch is now
+  in the same direction round the armature as the back pitch (fig. 22),
+  so that the beginning of the second loop, i.e. element No. 15, lies
+  outside the first loop. After p loops have been formed and as many
+  elements have been traversed as there are poles, the distance covered
+  either falls short of or exceeds a complete tour of the armature by
+  two winding-spaces, or the width of two elements. A second and third
+  tour are then made, and so on, until finally the winding again closes
+  upon itself. When the completed winding is developed as in fig. 23, it
+  is seen to work continuously forwards round the armature in zigzag
+  waves, one of which is marked in heavy lines, and the number of
+  complete tours is equal to the average of the back and front pitches.
+  Since the number of parallel circuits from brush to brush is q = 2,
+  the _E.M.F. equation of the wave-wound drum_ is E_a = pZ_a (N/60)[tau]
+  × 10^(-8) volts. Only two sets of brushes are necessary, but in order
+  to shorten the length of the commutator, other sets may also be added
+  at the point of highest and lowest potential up to as many in number
+  as there are poles. Thus the advantage of the wave-wound armature is
+  that for a given voltage and number of poles the number of active
+  wires is only 1/p of that in the lap-wound drum, each being of larger
+  cross-section in order to carry p times as much current; hence the
+  ratio of the room occupied by the insulation to the copper area is
+  less, and the available space is better utilized. A further advantage
+  is that the two circuits from brush to brush consist of elements
+  influenced by all the poles, so that if for any reason, such as
+  eccentricity of the armature within the bore of the pole-pieces, or
+  want of uniformity in the magnetic qualities of the poles, the flux of
+  each field is not equal to that of every other, the equality of the
+  voltage produced by the two halves of the winding is not affected
+  thereby.
+
+  In appearance the two classes of armatures, lap and wave, may be
+  distinguished in the barrel type of winding by the slope of the upper
+  layer of back end-connexions, and that of the front connexions at the
+  commutator end being parallel to one another in the latter, and
+  oppositely directed in the former.
+
+[Illustration: FIG. 24.]
+
+After completion of the winding, the end-connexions are firmly bound
+down by bands of steel or phosphor bronze binding wire, so as to resist
+the stress of centrifugal force. In the case of smooth-surface
+armatures, such bands are also placed at intervals along the length of
+the armature core, but in toothed armatures, although the coils are
+often in small machines secured in the slots by similar bands of a
+non-magnetic high-resistance wire, the use of hard-wood wedges driven
+into notches at the sides of the slots becomes preferable, and in very
+large machines indispensable. The external appearance of a typical
+armature with lap-winding is shown in fig. 24.
+
+
+  The commutator.
+
+A sound mechanical construction of the commutator is of vital importance
+to the good working of the continuous-current dynamo. The narrow,
+wedge-shaped sectors of hard-drawn copper, with their insulating strips
+of thin mica, are built up into a cylinder, tightly clamped together,
+and turned in the lathe; at each end a V-shaped groove is turned, and
+into these are fitted rings of micanite of corresponding section (fig.
+19); the whole is then slipped over a cast iron sleeve, and at either
+end strong rings are forced into the V-shaped grooves under great
+pressure and fixed by a number of closely-pitched tightening bolts. In
+dynamos driven by steam-turbines in which the peripheral speed of the
+commutator is very high, rings of steel are frequently shrunk on the
+surface of the commutator at either end and at its centre. But in every
+case the copper must be entirely insulated from the supporting body of
+metal by the interposition of mica or micanite and the prevention of any
+movement of the sectors under frequent and long-continued heating and
+cooling calls for the greatest care in both the design and the
+manufacture.
+
+
+  Forms of field-magnet.
+
+On passing to the second fundamental part of the dynamo, namely, the
+field-magnet, its functions may be briefly recalled as follows:--It has
+to supply the magnetic flux; to provide for it an iron path as nearly
+closed as possible upon the armature, save for the air-gaps which must
+exist between the pole-system and the armature core, the one stationary
+and the other rotating; and, lastly, it has to give the lines such
+direction and intensity within the air-gaps that they may be cut by the
+armature wires to the best advantage. Roughly corresponding to the three
+functions above summarized are the three portions which are more or less
+differentiated in the complete structure. These are: (1) the magnet
+"cores" or "_limbs_," carrying the exciting coils whereby the inert iron
+is converted into an electro-magnet; (2) the _yoke_, which joins the
+limbs together and conducts the flux between them; and (3) the
+_pole-pieces_, which face the armature and transmit the lines from the
+limbs through the air-gap to the armature core, or vice versa.
+
+  [Illustration: FIG. 25.]
+
+  Of the countless shapes which the field-magnet may take, it may be
+  said, without much exaggeration, that almost all have been tried; yet
+  those which have proved economical and successful, and hence have met
+  with general adoption, may be classed under a comparatively small
+  number of types. For bipolar machines the _single horse-shoe_ (fig.
+  25), which is the lineal successor of the permanent magnet employed in
+  the first magneto-electric machines, was formerly very largely used.
+  It takes two principal forms, according as the pole-pieces and
+  armature are above or beneath the magnet limbs and yoke. The
+  "over-type" form is best suited to small belt-driven dynamos, while
+  the "under-type" is admirably adapted to be directly driven by the
+  steam-engine, the armature shaft being immediately coupled to the
+  crank-shaft of the engine. In the latter case the magnet must be
+  mounted on non-magnetic supports of gun-metal or zinc, so as to hold
+  it at some distance away from the iron bedplate which carries both
+  engine and dynamo; otherwise a large proportion of the flux which
+  passes through the magnet limbs would leak through the bedplate across
+  from pole to pole without passing through the armature core, and so
+  would not be cut by the armature wires.
+
+  [Illustration: FIG. 26.]
+
+  Next may be placed the "Manchester" field (fig. 26)--the type of a
+  divided magnetic circuit in which the flux forming one field or pole
+  is divided between two magnets. An exciting coil is placed on each
+  half of the double horse-shoe magnet, the pair being so wound that
+  consequent poles are formed above and below the armature. Each magnet
+  thus carries one-half of the total flux, the lines of the two halves
+  uniting to form a common field where they issue forth into or leave
+  the air-gaps. The pole-pieces may be lighter than in the single
+  horse-shoe type, and the field is much more symmetrical, whence it is
+  well suited to ring armatures of large diameter. Yet these advantages
+  are greatly discounted by the excessive magnetic leakage, and by the
+  increased weight of copper in the exciting coils. Even if the greater
+  percentage which the leakage lines bear to the useful flux is
+  neglected, and the cross sectional area of each magnet core is but
+  half that of the equivalent single horse-shoe, the weight of wire in
+  the double magnet for the same rise of temperature in the coils must
+  be some 40% more than in the single horse-shoe, and the rate at which
+  energy is expended in heating the coils will exceed that of the single
+  horse-shoe in the same proportion.
+
+  Thirdly comes the two-pole _ironclad_ type, so called from the
+  exciting coil being more or less encased by the iron yoke; this latter
+  is divided into two halves, which pass on either side of the armature.
+  Unless the yoke be kept well away from the polar edges and armature,
+  the leakage across the air into the yoke becomes considerable,
+  especially if only one exciting coil is used, as in fig. 27 A; it is
+  better, therefore, to divide the excitation between two coils, as in
+  fig. 27 B, when the field also becomes symmetrical.
+
+  From this form is easily derived the _multipolar_ type of fig. 28 or
+  fig. 29, which is by far the most usual for any number of poles from
+  four upwards; its leakage coefficient is but small, and it is
+  economical in weight both of iron and copper.
+
+
+    Materials of magnets.
+
+  As regards the materials of which magnets are made, generally speaking
+  there is little difference in the permeability of "wrought iron" or
+  "mild steel forgings" and good "cast steel"; typical (B, H) curves
+  connecting the magnetizing force required with different
+  flux-densities for these materials are given under ELECTROMAGNETISM.
+  On the other hand there is a marked inferiority in the case of "cast
+  iron," which for a flux-density of B = 8000 C.G.S. lines per sq. cm.
+  requires practically the same number of ampere-turns per centimetre
+  length as steel requires for B = 16,000. Whatever the material, if the
+  flux-density be pressed to a high value the ampere-turns are very
+  largely increased owing to its approaching saturation, and this
+  implies either a large amount of copper in the field coils or an undue
+  expenditure of electrical energy in their excitation. Hence there is a
+  limit imposed by practical considerations to the density at which the
+  magnet should be worked, and this limit may be placed at about B =
+  16,000 for wrought iron or steel, and at half this value for cast
+  iron. For a given flux, therefore, the cast iron magnet must have
+  twice the sectional area and be twice as heavy, although this
+  disadvantage is partly compensated by its greater cheapness. If,
+  however, cast iron be used for the portion of the magnetic circuit
+  which is covered with the exciting coils, the further disadvantage
+  must be added that the weight of copper on the field-magnet is much
+  increased, so that it is usual to employ forgings or cast steel for
+  the magnet cores on which the coils are wound. If weight is not a
+  disadvantage, a cast iron yoke may be combined with the wrought iron
+  or cast steel magnet cores. An absence of joints in the magnetic
+  circuit is only desirable from the point of view of economy of expense
+  in machining the component parts during manufacture; when the surfaces
+  which abut against each other are drawn firmly together by screws, the
+  want of homogeneity at the joint, which virtually amounts to the
+  presence of a very thin film of air, produces little or no effect on
+  the total reluctance by comparison with the very much longer air-gaps
+  surrounding the armature. In order to reduce the eddy-currents in the
+  pole-pieces, due to the use of toothed armatures with relatively wide
+  slots, the poles themselves must be laminated, or must have fixed to
+  them laminated pole-shoes, built up of thin strips of mild steel
+  riveted together (as shown in fig. 29).
+
+  [Illustration: FIG. 27.]
+
+  [Illustration: FIG. 28.]
+
+  However it be built up, the mechanical strength of the magnet system
+  must be carefully considered. Any two surfaces between which there
+  exists a field of density B_g experience a force tending to draw them
+  together proportional to the square of the density, and having a value
+  of B_g²/(1.735 × 10^6) lb. per sq. in. of surface, over which the
+  density may be regarded as having the uniform value B_g. Hence, quite
+  apart from the torque with which the stationary part of the dynamo
+  tends to turn with the rotating part as soon as current is taken out
+  of the armature, there exists a force tending to make the pole-pieces
+  close on the armature as soon as the field is excited. Since both
+  armature and magnet must be capable of resisting this force, they
+  require to be rigidly held; although the one or the other must be
+  capable of rotation, there should otherwise be no possibility of one
+  part of the magnetic circuit shifting relatively to any other part. An
+  important conclusion may be drawn from this circumstance. If the
+  armature be placed exactly concentric within the bore of the poles,
+  and the two or more magnetic fields be symmetrical about a line
+  joining their centres, there is no tendency for the armature core to
+  be drawn in one direction more than in another; but if there is any
+  difference between the densities of the several fields, it will cause
+  an unbalanced stress on the armature and its shaft, under which it
+  will bend, and as this bending is continually reversed relatively to
+  the fibres of the shaft, they will eventually become weakened and give
+  way. Especially is this likely to take place in dynamos with short
+  air-gaps, wherein any difference in the lengths of the air-gaps
+  produces a much greater percentage difference in the flux-density than
+  in dynamos with long air-gaps. In toothed armatures with short
+  air-gaps the shaft must on this account be sufficiently strong to
+  withstand the stress without appreciable bending.
+
+
+  The magnetic circuit.
+
+Reference has already been made to the importance in dynamo design of
+the _predetermination of the flux_ due to a given number of ampere-turns
+wound on the field-magnet, or, conversely, of the number of ampere-turns
+which must be furnished by the exciting coils in order that a certain
+flux corresponding to one field may flow through the armature core from
+each pole. An equally important problem is the correct proportioning of
+the field-magnet, so that the useful flux Z_a may be obtained with the
+greatest economy in materials and exciting energy. The key to the two
+problems is to be found in the concept of a magnetic circuit as
+originated by H.A. Rowland and R.H.M. Bosanquet;[16] and the full
+solution of both may be especially connected with the name of Dr J.
+Hopkinson, from his practical application of the concept in his design
+of the Edison-Hopkinson machine, and in his paper on "Dynamo-Electric
+Machinery."[17] The publication of this paper in 1886 begins the second
+era in the history of the dynamo; it at once raised its design from the
+level of empirical rules-of-thumb to a science, and is thus worthy to be
+ranked as the necessary supplement of the original discoveries of
+Faraday. The process of predetermining the necessary ampere-turns is
+described in a simple case under ELECTROMAGNETISM. In its extension to
+the complete dynamo, it consists merely in the division of the magnetic
+circuit into such portions as have the same sectional area and
+permeability and carry approximately the same total flux; the difference
+of magnetic potential that must exist between the ends of each section
+of the magnet in order that the flux may pass through it is then
+calculated _seriatim_ for the several portions into which the magnetic
+circuit is divided, and the separate items are summed up into one
+magnetomotive force that must be furnished by the exciting coils.
+
+[Illustration: FIG. 29.]
+
+  The chief sections of the magnetic circuit are (1) the air-gaps, (2)
+  the armature core, and (3) the iron magnet.
+
+  The _air-gap_ of a dynamo with smooth-core armature is partly filled
+  with copper and partly with the cotton, mica, or other materials used
+  to insulate the core and wires; all these substances are, however,
+  sensibly non-magnetic, so that the whole interferric gap between the
+  iron of the pole-pieces and the iron of the armature may be treated as
+  an air-space, of which the permeability is constant for all values of
+  the flux density, and in the C.G.S. system is unity. Hence if l_g and
+  A_g be the length and area of the single air-gap in cm. and sq. cm.,
+  the reluctance of the double air-gap is 2l_g/A_g, and the difference
+  of magnetic potential required to pass Z_a lines over this reluctance
+  is Z_a·2l_g/A_g = B_g·2l_g; or, since one ampere-turn gives 1.257
+  C.G.S. units of magnetomotive force, the exciting power in
+  ampere-turns required over the two air-gaps is X_g = B_g·2l_g/1.257 =
+  0.8 B_g·2l_g. In the determination of the area A_g small allowance
+  must be made for the fringe of lines which extend beyond the actual
+  polar face. In the toothed armature with open slots, the lines are no
+  longer uniformly distributed over the air-gap area, but are graduated
+  into alternate bands of dense and weak induction corresponding to the
+  teeth and slots. Further, the lines curve round into the sides of the
+  teeth, so that their average length of path in the air and the air-gap
+  reluctance is not so easily calculated. Allowance must be made for
+  this by taking an increased length of air-gap = ml_g, where m is the
+  ratio _maximum density/mean density_, of which the value is chiefly
+  determined by the ratios of the width of tooth to width of slot and of
+  the width of slot to the air-gap between pole-face and surface of the
+  armature core.
+
+  The _armature core_ must be divided into the teeth and the core proper
+  below the teeth. Owing to the tapering section of the teeth, the
+  density rises towards their root, and when this reaches a high value,
+  such as 18,000 or more lines per sq. cm., the saturation of the iron
+  again forces an increasing proportion of the lines outwards into the
+  slot. A distinction must then be drawn between the "apparent"
+  induction which would hold if all the lines were concentrated in the
+  teeth, and the "real" induction. The area of the iron is obtained by
+  multiplying the number of teeth under the pole-face by their width and
+  by the net length of the iron core parallel to the axis of rotation.
+  The latter is the gross length of the armature less the space lost
+  through the insulating varnish or paper between the disks or through
+  the presence of ventilating ducts, which are introduced at intervals
+  along the length of the core. The former deduction averages about 7 to
+  10% of the gross length, while the latter, especially in large
+  multipolar machines, is an even more important item. Alter calculating
+  the density at different sections of the teeth, reference has now to
+  be made to a (B, H) or flux-density curve, from which may be found the
+  number of ampere-turns required per cm. length of path. This number
+  may be expressed as a function of the density in the teeth, and f(B_t)
+  be its average value over the length of a tooth, the ampere-turns of
+  excitation required over the teeth on either side of the core as the
+  lines of one field enter or leave the armature is X_t = f(B_t)·2l_t,
+  where l_t is the length of a single tooth in cm.
+
+  In the core proper below the teeth the length of path continually
+  shortens as we pass from the middle of the pole towards the centre
+  line of symmetry. On the other hand, as the lines gradually accumulate
+  in the core, their density increases from zero midway under the poles
+  until it reaches a maximum on the line of symmetry. The two effects
+  partially counteract one another, and tend to equalize the difference
+  of magnetic potential required over the paths of varying lengths; but
+  since the reluctivity of the iron increases more rapidly than the
+  density of the lines, we may approximately take for the length of path
+  (l_a) the minimum peripheral distance between the edges of adjacent
+  pole-faces, and then assume the maximum value of the density of the
+  lines as holding throughout this entire path. In ring and drum
+  machines the flux issuing from one pole divides into two halves in the
+  armature core, so that the maximum density of lines in the armature is
+  B_a = Z_a/2ab, where a = the radial depth of the disks in centimetres
+  and b = the net length of iron core. The total exciting power required
+  between the pole-pieces is therefore, at no load, X_p = X_g + X_t +
+  X_a, where X_a = f(B_a)·l_a; in order, however, to allow for the
+  effect of the armature current, which increases with the load, a
+  further term X_b, must be added.
+
+  [Illustration: Fig. 30.]
+
+  In the continuous-current dynamo it may be, and usually is, necessary
+  to move the brushes forward from the interpolar line of symmetry
+  through a small angle in the direction of rotation, in order to avoid
+  sparking between the brushes and the commutator (_vide infra_). When
+  the dynamo is giving current, the wires on either side of the diameter
+  of commutation form a current-sheet flowing along the surface of the
+  armature from end to end, and whatever the actual end-connexions of
+  the wires, the wires may be imagined to be joined together into a
+  system of loops such that the two sides of each loop are carrying
+  current in opposite directions. Thus a number of armature ampere-turns
+  are formed, and their effect on the entire system of magnet and
+  armature must be taken into account. So long as the diameter of
+  commutation coincides with the line of symmetry, the armature may be
+  regarded as a cylindrical electromagnet producing a flux of lines, as
+  shown in fig. 30. The direction of the self-induced flux in the
+  air-gaps is the same as that of the lines of the external field in one
+  quadrant on one side of DC, but opposed to it in the other quadrant on
+  the same side of DC; hence in the resultant field due to the combined
+  action of the field-magnet and armature ampere-turns, the flux is as
+  much strengthened over the one half of each polar face as it is
+  weakened over the other, and the total number of lines is unaffected,
+  although their distribution is altered. The armature ampere-turns are
+  then called _cross-turns_, since they produce a cross-field, which,
+  when combined with the symmetrical field, causes the leading
+  pole-corners ll to be weakened and the trailing pole-corners tt to be
+  strengthened, the neutral line of zero field being thus twisted
+  forwards in the direction of rotation. But when the brushes and
+  diameter of commutation are shifted forward, as shown in fig. 31, it
+  will be seen that a number of ampere-turns, forming a zone between the
+  lines Dn and mC, are in effect wound immediately on the magnetic
+  circuit proper, and this belt of ampere-turns is in direct opposition
+  to the ampere-turns of the field, as shown by the dotted and crossed
+  wires on the pole-pieces. The armature ampere-turns are then divisible
+  into the two bands, the _back-turns_, included within twice the angle
+  of lead [lambda], weakening the field, and the cross-turns, bounded by
+  the lines Dm, nC, again producing distortion of the weakened
+  symmetrical field. If, therefore, a certain flux is to be passed
+  through the armature core in opposition to the demagnetizing turns,
+  the difference of magnetic potential between the pole-faces must
+  include not only X_a, X_t, and X_g, but also an item X_b, in order to
+  balance the "back" ampere-turns of the armature. The amount by which
+  the brushes must be shifted forward increases with the armature
+  current, and in corresponding proportion the back ampere-turns are
+  also increased, their value being c[tau]2[lambda]/360°, where c = the
+  current carried by each of the [tau] active wires. Thus the term X_b,
+  takes into account the effect of the armature reaction on the total
+  flux; it varies as the armature current and angle of lead required to
+  avoid sparking are increased; and the reason for its introduction in
+  the fourth place (X_p = X_g + X_t + X_a + X_b), is that it increases
+  the magnetic difference of potential which must exist between the
+  poles of the dynamo, and to which the greater part of the leakage is
+  due. The leakage paths which are in parallel with the armature across
+  the poles must now be estimated, and so a new value be derived for the
+  flux at the commencement of the _iron-magnet_ path. If P = their joint
+  permeance, the leakage flux due to the difference of potential at the
+  poles is z_l = 1.257X_p × P, and this must be added to the useful flux
+  Z_a, or Z_p = Z_a + Z_l. There are also certain leakage paths in
+  parallel with the magnet cores, and upon the permeance of these a
+  varying number of ampere-turns is acting as we proceed along the
+  magnet coils; the magnet flux therefore increases by the addition of
+  leakage along the length of the limbs, and finally reaches a maximum
+  near the yoke. Either, then, the density in the magnet B_m = Z_m/A_m
+  will vary if the same sectional area be retained throughout, or the
+  sectional area of the magnet must itself be progressively increased.
+  In general, sufficient accuracy will be obtained by assuming a certain
+  number of additional leakage lines z_n as traversing the entire length
+  of magnet limbs and yoke (= l_m), so that the density in the magnet
+  has the uniform value B_m = (Z_p + z_n)/A_m. The leakage flux added on
+  actually within the length of the magnet core or z_n will be
+  approximately equal to half the total M.M.F. of the coils multiplied
+  by the permeance of the leakage paths around one coil. The
+  corresponding value of H can then be obtained from the (B, H) curve of
+  the material of which the magnet is composed, and the ampere-turns
+  thus determined must be added to X_p, or X = X_p + X_m, where X_m =
+  f(B_m)l_m. The final equation for the exciting power required on a
+  magnetic circuit as a whole will therefore take the form
+
+    X = A[Tau] = 0.8B_g·2l_g + f(B_t)2l_t + f(B_a)l_a + X_b + f(B_m)l_m. (3)
+
+  If the magnet cores are of wrought iron or cast steel, and the yoke is
+  of cast iron, the last term must be divided into two portions
+  corresponding to the different materials, i.e. into f(B_m)l_m +
+  f(B_y)l_y. In the ordinary multipolar machine with as many
+  magnet-coils as there are poles, each coil must furnish half the above
+  number of ampere-turns.
+
+  [Illustration: FIG. 31.]
+
+
+    Magnetic leakage.
+
+  Since no substance is impermeable to the passage of magnetic flux, the
+  only form of magnetic circuit free from leakage is one uniformly wound
+  with ampere-turns over its whole length. The reduction of the
+  _magnetic leakage_ to a minimum in any given type is therefore
+  primarily a question of distributing the winding as far as possible
+  uniformly upon the circuit, and as the winding must be more or less
+  concentrated into coils, it resolves itself into the necessity of
+  introducing as long air-paths as possible between any surfaces which
+  are at different magnetic potentials. No iron should be brought near
+  the machine which does not form part of the magnetic circuit proper,
+  and especially no iron should be brought near the poles, between which
+  the difference of magnetic potential practically reaches its maximum
+  value. In default of a machine of the same size or similar type on
+  which to experiment, the probable direction of the leakage flux must
+  be assumed from the drawing, and the air surrounding the machine must
+  be mapped out into areas, between which the permeances are calculated
+  as closely as possible by means of such approximate formulae as those
+  devised by Professor G. Forbes.
+
+
+    Excitation of field-magnet.
+
+  In the earliest "magneto-electric" machines permanent steel magnets,
+  either simple or compound, were employed, and for many years these
+  were retained in certain alternators, some of which are still in use
+  for arc lighting in lighthouses. But since the field they furnish is
+  very weak, a great advance was made when they were replaced by soft
+  iron electromagnets, which could be made to yield a much more intense
+  flux. As early as 1831 Faraday[18] experimented with electromagnets,
+  and after 1850 they gradually superseded the permanent magnet. When
+  the total ampere-turns required to excite the electromagnet have been
+  determined, it remains to decide how the excitation shall be obtained;
+  and, according to the method adopted, continuous-current machines may
+  be divided into four well-defined classes.
+
+  [Illustration: FIG. 32.]
+
+  The simplest method, and that which was first used, is _separate
+  excitation_ from some other source of direct current, which may be
+  either a primary or a secondary battery or another dynamo (fig. 32).
+  But since the armature yields a continuous current, it was early
+  suggested (by J. Brett in 1848 and F. Sinsteden in 1851) that this
+  current might be utilized to increase the flux; combinations of
+  permanent and electromagnets were therefore next employed, acting
+  either on the main armature or on separate armatures, until in 1867 Dr
+  Werner von Siemens and Sir C. Wheatstone almost simultaneously
+  discovered that the dynamo could be made _self-exciting_ through the
+  residual magnetism retained in the soft iron cores of the
+  electromagnet. The former proposed to take the whole of the current
+  round the magnet coils which were in series with the armature and
+  external circuit, while the latter proposed to utilize only a portion
+  derived by a shunt from the main circuit; we thus arrive at the second
+  and third classes, namely, _series_ and _shunt_ machines. The starting
+  of the process of excitation in either case is the same; when the
+  brushes are touching the commutator and the armature is rotated, the
+  small amount of flux left in the magnet is cut by the wires, and a
+  very small current begins to flow round the closed circuit; this
+  increases the flux, which in turn further increases the E.M.F. and
+  current, until, finally, the cumulative effect stops through the
+  increasing saturation of the iron cores. Fig. 33, illustrating the
+  _series_ machine, shows the winding of the exciting coils to be
+  composed of a few turns of thick wire. Since the current is undivided
+  throughout the whole circuit, the resistance of both the armature and
+  field-magnet winding must be low as compared with that of the external
+  circuit, if the useful power available at the terminals of the machine
+  is to form a large percentage of the total electrical power--in other
+  words, if the efficiency is to be high. Fig. 34 shows the third
+  method, in which the winding of the field-magnets is a _shunt_ or
+  fine-wire circuit of many turns applied to the terminals of the
+  machine; in this ease the resistance of the shunt must be high as
+  compared with that of the external circuit, in order that only a small
+  proportion of the total energy may be absorbed in the field.
+
+  [Illustration: FIG. 33.]
+
+  [Illustration: FIG. 34.]
+
+  Since the whole of the armature current passes round the field-magnet
+  of the series machine, any alteration in the resistance of the
+  external circuit will affect the excitation and also the voltage. A
+  curve connecting together corresponding values of external current and
+  terminal voltage for a given speed of rotation is known as the
+  _external-characteristic_ of the machine; in its main features it has
+  the same appearance as a curve of magnetic flux, but when the current
+  exceeds a certain amount it begins to bend downwards and the voltage
+  decreases. The reason for this will be found in the armature reaction
+  at large loads, which gradually produces a more and more powerful
+  demagnetizing effect, as the brushes are shifted forwards to avoid
+  sparking; eventually the back ampere-turns overpower any addition to
+  the field that would otherwise be due to the increased current flowing
+  round the magnet. The "external characteristic" for a shunt machine
+  has an entirely different shape. The field-magnet circuit being
+  connected in parallel with the external circuit, the exciting current,
+  if the applied voltage remains the same, is in no way affected by
+  alterations in the resistance of the latter. As, however, an increase
+  in the external current causes a greater loss of volts in the armature
+  and a greater armature reaction, the terminal voltage, which is also
+  the exciting voltage, is highest at no load and then diminishes. The
+  fall is at first gradual, but after a certain critical value of the
+  armature current is reached, the machine is rapidly demagnetized and
+  loses its voltage entirely.
+
+  [Illustration: FIG. 35.]
+
+  The last method of excitation, namely, _compound-winding_ (fig. 35),
+  is a combination of the two preceding, and was first used by S.A.
+  Varley and by C.F. Brush. If a machine is in the first instance
+  shunt-wound, and a certain number of series-turns are added, the
+  latter, since they carry the external current, can be made to
+  counteract the effect which the increased external current would have
+  in lowering the voltage of the simple shunt machine. The ampere-turns
+  of the series winding must be such that they not only balance the
+  increase of the demagnetizing back ampere-turns on the armature, but
+  further increase the useful flux, and compensate for the loss of volts
+  over their own resistance and that of the armature. The machine will
+  then give for a constant speed a nearly constant voltage at its
+  terminals, and the curve of the external characteristic becomes a
+  straight line for all loads within its capacity. Since with most prime
+  movers an increase of the load is accompanied by a drop in speed, this
+  effect may also be counteracted; while, lastly, if the series-turns
+  are still further increased, the voltage may be made to rise with an
+  increasing load, and the machine is "over-compounded."
+
+
+  Commutation and sparking at the brushes.
+
+At the initial moment when an armature coil is first short-circuited by
+the passage of the two sectors forming its ends under the contact
+surface of a brush, a certain amount of electromagnetic energy is stored
+up in its magnetic field as linked with the ampere-turns of the coil
+when carrying its full share of the total armature current. During the
+period of short-circuit this quantity of energy has to be dissipated as
+the current falls to zero, and has again to be re-stored as the current
+is reversed and raised to the same value, but in the opposite direction.
+The period of short-circuit as fixed by the widths of the brush and of
+the mica insulation between the sectors, and by the peripheral speed of
+the commutator is extremely brief, and only lasts on an average from
+(1/200)th to (1/1000)th of a second. The problem of sparkless
+commutation is therefore primarily a question of our ability to
+dissipate and to re-store the required amount of energy with sufficient
+rapidity.
+
+An important aid towards the solution of this problem is found in the
+effect of the varying contact-resistance between the brush and the
+surfaces of the leading and trailing sectors which it covers. As the
+commutator moves under the brush, the area of contact which the brush
+makes with the leading sector diminishes, and the resistance between the
+two rises; conversely, the area of contact between the brush and the
+trailing sector increases and the resistance falls. This action tends
+automatically to bring the current through each sector into strict
+proportionality to the amount of its surface which is covered by the
+brush, and so to keep the current-density and the loss of volts over the
+contacts uniform and constant. As soon as the current-density in the two
+portions of the brush becomes unequal, a greater amount of heat is
+developed at the commutator surface, and this in the first place affords
+an additional outlet for the dissipation of the stored energy of the
+coil, while after reversal of the current it is the accompaniment of a
+re-storage of the required energy. This energy, as well as that which is
+spent in heating the coil, can in fact, in default of other sources, be
+derived through the action of the unequal current-density from the
+electrical output of the rest of the armature winding, and so only
+indirectly from the prime mover.
+
+In practice, when the normal contact-resistance of the brushes is low
+relatively to the resistance of the coil, as is the case with metal
+brushes of copper or brass gauze, but little benefit can be obtained
+from the action of the varying contact-resistance. It exerts no
+appreciable effect until close towards the end of the period of
+short-circuit, and then only with such a high-current-density at the
+trailing edge of the leaving sector that at the moment of parting the
+brush-tip is fused, or its metal volatilized, and sparking has in fact
+set in. With such brushes, then, it becomes necessary to call in the aid
+of a reversing E.M.F. impressed upon the coil by the magnetic field
+through which it is moving. If such a reversing field comes into action
+while the current is still unreversed, its E.M.F. is opposed to the
+direction of the current, and the coil is therefore driving the armature
+forward as in a motor; it thus affords a ready means of rapidly
+dissipating part of the initial energy in the form of mechanical work
+instead of as heat. After the current has been reversed, the converse
+process sets in, and the prime mover directly expends mechanical energy
+not only in heating the coil, but also in storing up electromagnetic
+energy with a rapidity dependent upon the strength of the reversing
+field. The required direction of external field can be obtained in the
+dynamo by shifting the brushes forward, so that the short-circuited coil
+enters into the fringe of lines issuing from the leading pole-tip, i.e.
+by giving the brushes an "angle of lead." An objection to this process
+is that the main flux is thereby weakened owing to the belt of back
+ampere-turns which arises (_v. supra_). A still greater objection is
+that the amount of the angle of lead must be suited to the value of the
+load, the corrective power of copper brushes being very small if the
+reversing E.M.F. is not closely adjusted in proportion to the armature
+current.
+
+On this account metal brushes have been almost entirely superseded by
+carbon moulded into hard blocks. With these, owing to their higher
+specific contact-resistance, a very considerable reversing effect can be
+obtained through the action of unequal current-density, and indeed in
+favourable cases complete sparklessness can be obtained throughout the
+entire range of load of the machine with a fixed position of the
+brushes. Yet if the work which they are called upon to perform exceeds
+certain limits, they tend to become overheated with consequent glowing
+or sparking at their tips, so that, wherever possible, it is advisable
+to reinforce their action by a certain amount of reversing field, the
+brushes being set so that its strength is roughly correct for, say, half
+load.
+
+In the case of dynamos driven by steam-turbines, sparkless commutation
+is especially difficult to obtain owing to the high speed of rotation
+and the very short space of time in which the current has to be
+reversed. Special "reversing poles" then become necessary; these are
+wound with magnetizing coils in series with the main armature current,
+so that the strength of field which they yield is roughly proportional
+to the current which has to be reversed. These again may be combined
+with a "compensating winding" embedded in the pole-faces and carrying
+current in the opposite direction to the armature ampere-turns, so as to
+neutralize the cross effect of the latter and prevent distortion of the
+resultant field.
+
+
+    Heating effects.
+
+  From the moment that a dynamo begins to run with excited field, heat
+  is continuously generated by the passage of the current through the
+  windings of the field-magnet coils and the armature, as well as by the
+  action of hysteresis and eddy currents in the armature and
+  pole-pieces. Whether the source of the heat be in the field-magnet or
+  in the armature, the mass in which it originates will continue to rise
+  in temperature until such a difference of temperature is established
+  between itself and the surrounding air that the rate at which the heat
+  is carried off by radiation, convection and conduction is equal to the
+  rate at which it is being generated. Evidently, then, the temperature
+  which any part of the machine attains after a prolonged run must
+  depend on the extent and effectiveness of the cooling surface from
+  which radiation takes place, upon the presence or absence of any
+  currents of air set up by the rotation of itself or surrounding parts,
+  and upon the presence of neighbouring masses of metal to carry away
+  the heat by conduction. In the field-magnet coils the rate at which
+  heat is being generated is easily determined, since it is equal to the
+  square of the current passing through them multiplied by their
+  resistance. Further, the magnet is usually stationary, and only
+  indirectly affected by draughts of air due to the rotating armature.
+  Hence for machines of a given type and of similar proportions, it is
+  not difficult to decide upon some method of reckoning the cooling
+  surface of the magnet coils S_c, such that the rise of temperature
+  above that of the surrounding air may be predicted from an equation of
+  the form t° = kW/S_c, where W = the rate in watts at which heat is
+  generated in the coils, and k is some constant depending upon the
+  exact method of reckoning their cooling surface. As a general rule the
+  cooling surface of a field-coil is reckoned as equal to the exposed
+  outer surface of its wire, the influence of the end flanges being
+  neglected, or only taken into account in the case of very short
+  bobbins wound with a considerable depth of wire. In the case of the
+  rotating armature a similar formula must be constructed, but with the
+  addition of a factor to allow for the increase in the effectiveness of
+  any given cooling surface due to the rotation causing convection
+  currents in the surrounding air. Only experiment can determine the
+  exact effect of this, and even with a given type of armature it is
+  dependent on the number of poles, each of which helps to break up the
+  air-currents, and so to dissipate the heat. For example, in two-pole
+  machines with drum bar-armatures, if the cooling surface be reckoned
+  as equal to the cylindrical exterior plus the area of the two ends,
+  the heating coefficient for a peripheral speed of 1500 ft. per minute
+  is less than half of that for the same armature when at rest. A
+  further difficulty still meets the designer in the correct
+  predetermination of the total loss of watts in an armature before the
+  machine has been tested. It is made up of three separate items,
+  namely, the copper loss in the armature winding, the loss by
+  hysteresis in the iron, and the loss by eddy currents, which again may
+  be divided into those in the armature bars and end-connexions, and
+  those in the core and its end-plates. The two latter items are both
+  dependent upon the speed of the machine; but whereas the hysteresis
+  loss is proportional to the speed for a given density of flux in the
+  armature, the eddy current loss is proportional to the square of the
+  speed, and owing to this difference, the one loss can be separated
+  from the other by testing an armature at varying speeds. Thus for a
+  given rise of temperature, the question of the amount of current which
+  can be taken out of an armature at different speeds depends upon the
+  proportion which the hysteresis and eddy watts bear to the copper
+  loss, and the ratio in which the effectiveness of the cooling surface
+  is altered by the alteration in speed. Experimental data, again, can
+  alone decide upon the amount of eddy currents that may be expected in
+  given armatures, and caution is required in applying the results of
+  one machine to another in which any of the conditions, such as the
+  number of poles, density in the teeth, proportions of slot depth to
+  width, &c., are radically altered.
+
+  It remains to add, that the rise of temperature which may be permitted
+  in any part of a dynamo after a prolonged run is very generally placed
+  at about 70° Fahr. above the surrounding air. Such a limit in ordinary
+  conditions of working leads to a final temperature of about 170°
+  Fahr., beyond which the durability of the insulation of the wires is
+  liable to be injuriously affected. Upon some such basis the output of
+  a dynamo in continuous working is rated, although for short periods
+  of, say, two hours the normal full-load current of a large machine may
+  be exceeded by some 25% without unduly heating the armature.
+
+
+  Uses of continuous current dynamos.
+
+For the electro-deposition of metals or the electrolytic treatment of
+ores a continuous current is a necessity; but, apart from such use, the
+purposes from which the continuous-current dynamo is well adapted are so
+numerous that they cover nearly the whole field of electrical
+engineering, with one important exception. To meet these various uses,
+the pressures for which the machine is designed are of equally wide
+range; for the transmission of power over long distances they may be as
+high as 3000 volts, and for electrolytic work as low as five. Each
+electrolytic bath, with its leads, requires on an average only some four
+or five volts, so that even when several are worked in series the
+voltage of the dynamo seldom exceeds 60. On the other hand, the current
+is large and may amount to as much as from 1000 to 14,000 amperes,
+necessitating the use of two commutators, one at either end of the
+armature, in order to collect the current without excessive heating of
+the sectors and brushes. The field-magnets are invariably shunt-wound,
+in order to avoid reversal of the current through polarization at the
+electrodes of the bath. For incandescent lighting by glow lamps, the
+requirements of small isolated installations and of central stations for
+the distribution of electrical energy over large areas must be
+distinguished. For the lighting of a private house or small factory, the
+dynamo giving from 5 to 100 kilo-watts of output is commonly wound for a
+voltage of 100, and is driven by pulley and belt from a gas, oil or
+steam-engine; or, if approaching the higher limit above mentioned, it is
+often directly coupled to the crank-shaft of the steam-engine. If used
+in conjunction with an accumulator of secondary cells, it is
+shunt-wound, and must give the higher voltage necessary to charge the
+battery; otherwise it is compound-wound, in order to maintain the
+pressure on the lamps constant under all loads within its capacity. The
+compound-wound dynamo is likewise the most usual for the lighting of
+steamships, and is then directly coupled to its steam-engine; its output
+seldom exceeds 100 kilo-watts, at a voltage of 100 or 110. For larger
+installations a voltage of 250 is commonly used, while for
+central-station work, economy in the distributing mains dictates a
+higher voltage, especially in connexion with a three-wire system; the
+larger dynamos may then give 500 volts, and be connected directly across
+the two outer wires. A pair of smaller machines coupled together, and
+each capable of giving 250 volts, are often placed in series across the
+system, with their common junction connected to the middle wire; the one
+which at any time is on the side carrying the smaller current will act
+as a motor and drive the other as a dynamo, so as to balance the system.
+The directly-coupled steam dynamo may be said to have practically
+displaced the belt- or rope-driven sets which were formerly common in
+central stations. The generating units of the central station are
+arranged in progressive sizes, rising from, it may be, 250 or 500
+horse-power up to 750 or 1000, or in large towns to as much as 5000
+horse-power. If for lighting only, they are usually shunt-wound, the
+regulation of the voltage, to keep the pressure constant on the
+distributing system under the gradual changes of load, being effected by
+variable resistances in the shunt circuit of the field-magnets.
+
+Generators used for supplying current to electric tramways are commonly
+wound for 500 volts at no load and are over-compounded, so that the
+voltage rises to 550 volts at the maximum load, and thus compensates for
+the loss of volts over the transmitting lines. For arc lighting it was
+formerly usual to employ a class of dynamo which, from the nature of its
+construction, was called an "open-coil" machine, and which gave a
+unidirectional but pulsating current. Of such machines the Brush and
+Thomson-Houston types were very widely used; their E.M.F. ranged from
+2000 to 3000 volts for working a large number of arcs in series, and by
+means of special regulators their current was maintained constant over a
+wide range of voltage. But as their efficiency was low and they could
+not be applied to any other purpose, they have been largely superseded
+in central stations by closed-coil dynamos or alternators, which can
+also be used for incandescent lighting. In cases where the central
+station is situated at some distance from the district to which the
+electric energy is to be supplied, voltages from 1000 to 2000 are
+employed, and these are transformed down at certain distributing centres
+by continuous-current transformers (see TRANSFORMERS and ELECTRICITY
+SUPPLY). These latter machines are in reality motor-driven dynamos, and
+hence are also called _motor-generators_; the armatures of the motor and
+dynamo are often wound on the same core, with a commutator at either
+end, the one to receive the high-pressure motor current, and the other
+to collect the low-pressure current furnished by the dynamo.
+
+  In all large central stations it is necessary that the dynamos should
+  be capable of being run _in parallel_, so that their outputs may be
+  combined on the same "omnibus bars" and thence distributed to the
+  network of feeders. With simple shunt-wound machines this is easily
+  effected by coupling together terminals of like sign when the voltage
+  of the two or more machines are closely equal. With compound-wound
+  dynamos not only must the external terminals of like sign be coupled
+  together, but the junctions of the brush leads with the series winding
+  must be connected by an "equalizing" lead of low resistance;
+  otherwise, should the E.M.F. of one machine for any reason fall below
+  the voltage of the omnibus bars, there is a danger of its polarity
+  being reversed by a back current from the others with which it is in
+  parallel.
+
+  Owing to the necessary presence in the continuous-current dynamo of
+  the commutator, with its attendant liability to sparking at the
+  brushes, and further, owing to the difficulty of insulating the
+  rotating armature wires, a pressure of 3000 volts has seldom been
+  exceeded in any one continuous-current machine, and has been given
+  above as the limiting voltage of the class. If therefore it is
+  required to work with higher pressures in order to secure economy in
+  the transmitting lines, two or more machines must be coupled _in
+  series_ by connecting together terminals which are of unlike sign.[19]
+  The stress of the total voltage may still fall on the insulation of
+  the winding from the body of the machine; hence for high-voltage
+  transmission of power over very long distances, the continuous-current
+  dynamo in certain points yields in convenience to the alternator. In
+  this there is no commutator, the armature coils may be stationary and
+  can be more thoroughly insulated, while further, if it be thought
+  undesirable to design the machine for the full transmitting voltage,
+  it is easy to wind the armature for a low pressure; this can be
+  subsequently transformed up to a high pressure by means of the
+  alternating-current transformer, which has stationary windings and so
+  high an efficiency that but little loss arises from its use. With
+  these remarks, the transition may be made to the fuller discussion of
+  the alternator.
+
+
+_Alternators._
+
+  Frequency.
+
+The frequency employed in alternating-current systems for distributing
+power and light varies between such wide limits as 25 and 133; yet in
+recent times the tendency has been towards standard frequencies of 25,
+50 and 100 as a maximum. High frequencies involve more copper in the
+magnet coils, owing to the greater number of poles, and a greater loss
+of power in their excitation, but the alternator as a whole is somewhat
+lighter, and the transformers are cheaper. On the other hand, high
+frequency may cause prejudicial effects, due to the inductance and
+capacity of the distributing lines; and in asynchronous motors used on
+polyphase systems the increased number of poles necessary to obtain
+reasonable speeds reduces their efficiency, and is otherwise
+disadvantageous, especially for small horse-powers. A frequency lower
+than 40 is, however, not permissible where arc lighting is to form any
+considerable portion of the work and is to be effected by the
+alternating current without rectification, since below this value the
+eye can detect the periodic alteration in the light as the carbons
+alternately cool and become heated. Thus for combined lighting and power
+50 or 60 are the most usual frequencies; but if the system is designed
+solely or chiefly for the distribution of power, a still lower frequency
+is preferable. On this account 25 was selected by the engineers for the
+Niagara Falls power transmission, after careful consideration of the
+problem, and this frequency has since been widely adopted in similar
+cases.
+
+
+  Alternator construction.
+
+The most usual type of heteropolar alternator has an internal rotating
+field-magnet system, and an external stationary armature, as in fig. 10.
+The coils of the armature, which must for high voltages be heavily
+insulated, are then not subjected to the additional stresses due to
+centrifugal force; and further, the collecting rings which must be
+attached to the rotating portion need only transmit the exciting current
+at a low voltage.
+
+[Illustration: FIG. 36.]
+
+The homopolar machine possesses the advantages that only a single
+exciting coil is required, whatever the number of polar projections, and
+that both the armature and field-magnet coils may be stationary. From
+fig. 8 it will be seen that it is not essential that the exciting coil
+should revolve with the internal magnet, but it may be supported from
+the external stationary armature while still embracing the central part
+of the rotor. The E.M.F. is set up in the armature coils through the
+periodic variation of the flux through them as the iron projections
+sweep past, and these latter may be likened to a number of "keepers,"
+which complete the magnetic circuit. From the action of the rotating
+iron masses they may also be considered as the inducing elements or
+"inductors," and the homopolar machine is thence also known as the
+"inductor alternator." If the end of the rotor marked S in fig. 8 is
+split up into a number of S polar projections similar to the N poles, a
+second set of armature coils may be arranged opposite to them, and we
+obtain an inductor alternator with double armature. Or the polar
+projections at the two ends may be staggered, and a single armature
+winding be passed straight through the armature, as in fig. 36, which
+shows at the side the appearance of the revolving inductor with its
+crown of polar projections in one ring opposite to the gaps between the
+polar projections of the other ring. But in spite of its advantage of
+the single stationary exciting coil, the inductor alternator has such a
+high degree of leakage, and the effect of armature reaction is so
+detrimental in it, that the type has been gradually abandoned, and a
+return has been almost universally made to the heteropolar alternator
+with internal poles radiating outwards from a circular yoke-ring. The
+construction of a typical machine of this class is illustrated in fig.
+37.
+
+[Illustration: FIG. 37.]
+
+Since the field-magnet coils rotate, they must be carefully designed to
+withstand centrifugal force, and are best composed of flat copper strip
+wound on edge with thin insulation between adjacent layers. The coil is
+secured by the edges of the pole-shoes which overhang the pole and
+tightly compress the coil against the yoke-ring; the only effect from
+centrifugal force is then to compress still further the flat turns of
+copper against the pole-shoes without deformation. The poles are either
+of cast steel of circular or oblong section, bolted to the rim of the
+yoke-ring, or are built up of thin laminations of sheet steel. When the
+peripheral speed is very high, the yoke-ring will be of cast steel or
+may itself be built up of sheet steel laminations, this material being
+reliable and easily tested to ensure its sound mechanical strength. If
+the armature slots are open, the pole-pieces will in any case be
+laminated to reduce the eddy currents set up by the variation of the
+flux-density.
+
+Owing to the great number of poles[20] of the alternator when driven by
+a reciprocating steam-engine, the diameter of its rotor is usually
+larger and its length less than in the continuous-current dynamo of
+corresponding output. The support of the armature core when of large
+diameter is therefore a more difficult problem, since, apart from any
+magnetic strains to which it may be subjected, its own weight tends to
+deform it. The segmental core-disks are usually secured to the internal
+circumference of a circular cast iron frame; the latter has a box
+section of considerable radial depth to give stiffness to it, and the
+disks are tightly clamped between internal flanges, one being a fixed
+part of the frame and the other loose, with transverse bolts passing
+right through from side to side (fig. 37). In order to lessen the weight
+of the structure and its expense in material, the cast iron frame has in
+some cases been entirely dispensed with, and braced tie-rods have been
+used to render the effective iron of the armature core-disks
+self-supporting.
+
+[Illustration: FIG. 38.]
+
+Owing to the high speed of the turbo-alternator, its rotor calls for the
+utmost care in its design to withstand the effect of centrifugal force
+without any shifting of the exciting coils, and to secure a perfect
+balance.
+
+The appearance of the armature of a typical three-phase alternator is
+illustrated in fig. 38, which shows a portion of the lower half after
+removal of the field-magnet.
+
+With open slots the coils, after being wound on formers to the required
+shape, are thoroughly impregnated with insulating compound, dried, and
+after a further wrapping with several layers of insulating material,
+finally pressed into the slots together with a sheet of leatheroid or
+flexible micanite. The end-connexions of each group of coils of one
+phase project straight out from the slots or are bent upwards
+alternately with those of the other phases, so that they may clear one
+another (fig. 37). A wooden wedge driven into a groove at the top of
+each slot is often used to lock the coil in place. With slots nearly
+closed at the top, the coils are formed by hand by threading the wire
+through tubes of micanite or specially prepared paper lining the slots;
+or with single-turn loops, stout bars of copper of [U]-shape can be
+driven through the slots and closed by soldered connexions at the other
+end.
+
+
+    Shape of E.M.F. curve.
+
+  The first experimental determination of the shape of the E.M.F. curve
+  of an alternator was made by J. Joubert in 1880. A revolving
+  contact-maker charged a condenser with the E.M.F. produced by the
+  armature at a particular instant during each period. The condenser was
+  discharged through a ballistic galvanometer, and from the measured
+  throw the instantaneous E.M.F. could be deduced. The contact-maker was
+  then shifted through a small angle, and the instantaneous E.M.F. at
+  the new position corresponding to a different moment in the period was
+  measured; this process was repeated until the E.M.F. curve for a
+  complete period could be traced. Various modifications of the same
+  principle have since been used, and a form of "oscillograph" (q.v.)
+  has been perfected which is well adapted for the purpose of tracing
+  the curves both of E.M.F. and of current. The machine on which Joubert
+  carried out his experiments was a Siemens disk alternator having no
+  iron in its armature, and it was found that the curve of E.M.F. was
+  practically identical with a sine curve. The same law has also been
+  found to hold true for a smooth-core ring or drum armature, but the
+  presence of the iron core enables the armature current to produce
+  greater distorting effect, so that the curves under load may vary
+  considerably from their shape at no load. In toothed armatures, the
+  broken surface of the core, and the still greater reaction from the
+  armature current, may produce wide variations from the sine law, the
+  general tendency being to give the E.M.F. curve a more peaked form.
+  The great convenience of the assumption that the E.M.F. obeys the sine
+  law has led to its being very commonly used as the basis for the
+  mathematical analysis of alternator problems; but any deductions made
+  from this premiss require to be applied with caution if they are
+  likely to be modified by a different shape of the curve. Further, the
+  same alternator will give widely different curves even of E.M.F., and
+  still more so of current, according to the nature of the external
+  circuit to which it is connected. As will be explained later, the
+  phase of the current relatively to the E.M.F. depends not only on the
+  inductance of the alternator itself, but also upon the inductance and
+  capacity of the external circuit, so that the same current will
+  produce different effects according to the amount by which it lags or
+  leads. The question as to the relative advantages of differently
+  shaped E.M.F. curves has led to much discussion, but can only be
+  answered by reference to the nature of the work that the alternator
+  has to do--i.e. whether it be arc lighting, motor driving, or
+  incandescent lighting through transformers. The shape of the E.M.F.
+  curve is, however, of great importance in one respect, since upon it
+  depends the ratio of the maximum instantaneous E.M.F. to the effective
+  value, and the insulation of the entire circuit, both external and
+  internal, must be capable of withstanding the maximum E.M.F. While the
+  maximum value of the sine curve is [root]2 or 1.414 times the
+  effective value, the maximum value of a [Lambda] curve is 1.732 times
+  the effective value, so that for the same effective E.M.F. the
+  armature wires must not only be more heavily insulated than in the
+  continuous-current dynamo, but also the more peaked the curve the
+  better must be the insulation.
+
+
+    Excitation.
+
+  Since an alternating current cannot be used for exciting the
+  field-magnet, recourse must be had to some source of a direct current.
+  This is usually obtained from a small auxiliary continuous-current
+  dynamo, called an _exciter_, which may be an entirely separate
+  machine, separately driven and used for exciting several alternators,
+  or may be driven from the alternator itself; in the latter case the
+  armature of the exciter is often coupled directly to the rotating
+  shaft of the alternator, while its field-magnet is attached to the
+  bed-plate. Although separate excitation is the more usual method, the
+  alternator can also be made self-exciting if a part or the whole of
+  the alternating current is "rectified," and thus converted into a
+  direct current.
+
+
+    Quarter-phase alternators.
+
+  The general idea of the polyphase alternator giving two or more
+  E.M.F.'s of the same frequency, but displaced in phase, has been
+  already described. The several phases may be entirely independent, and
+  such was the case with the early polyphase machines of Gramme, who
+  used four independent circuits, and also in the large two-phase
+  alternators designed by J.E.H. Gordon in 1883. If the phases are thus
+  entirely separate, each requires two collector rings and two wires to
+  its external circuit, i.e. four in all for two-phase and six for
+  three-phase machines. The only advantage of the polyphase machine as
+  thus used is that the whole of the surface of the armature core may be
+  efficiently covered with winding, and the output of the alternator for
+  a given size be thereby increased. It is, however, also possible so to
+  interlink the several circuits of the armature that the necessary
+  number of transmitting lines to the external circuits may be reduced,
+  and also the weight of copper in them for a given loss in the
+  transmission.[21] The condition which obviously must be fulfilled,
+  for such interlinking of the phases to be possible, is that in the
+  lines which are to meet at any common junction the algebraic sum of
+  the instantaneous currents, reckoned as positive if away from such
+  junction and as negative if towards it, must be zero. Thus if the
+  phases be diagrammatically represented by the relative angular
+  position of the coils in fig. 39, the current in the coils A and B
+  differs in phase from the current in the coils C and D by a quarter of
+  a period or 90°; hence if the two wires b and d be replaced by the
+  single wire bd, this third wire will serve as a common path for the
+  currents of the two phases either outwards or on their return. At any
+  instant the value of the current in the third wire must be the vector
+  sum of the two currents in the other wires, and if the shape of the
+  curves of instantaneous E.M.F. and current are identical, and are
+  assumed to be sinusoidal, the effective value of the current in the
+  third wire will be the vector sum of the effective values of the
+  currents in the other wires; in other words, if the system is
+  balanced, the effective current in the third wire is [root]2, or 1.414
+  times the current in either of the two outer wires. Since the currents
+  of the two phases do not reach their maximum values at the same time,
+  the sectional area of the third wire need not be twice that of the
+  others; in order to secure maximum efficiency by employing the same
+  current density in all three wires, it need only be 40% greater than
+  that of either of the outer wires. The effective voltage between the
+  external leads may in the same way be calculated by a vector diagram,
+  and with the above _star connexion_ the voltage between the outer pair
+  of wires a and c is [root]2, or 1.414 times the voltage between either
+  of the outer wires and the common wire bd. Next, if the four coils are
+  joined up into a continuous helix, just as in the winding of a
+  continuous-current machine, four wires may be attached to equidistant
+  points at the opposite ends of two diameters at right angles to each
+  other (fig. 40). Such a method is known as the _mesh connexion_, and
+  gives a perfectly symmetrical four-phase system of distribution. Four
+  collecting rings are necessary if the armature rotates, and there is
+  no saving in copper in the transmitting lines; but the importance of
+  the arrangement lies in its use in connexion with rotary converters,
+  in which it is necessary that the winding of the armature should form
+  a closed circuit. If e = the effective voltage of one phase A, the
+  voltage between any pair of adjacent lines in the diagram is e, and
+  between m and o or n and p is e [root]2. The current in any line is
+  the resultant of the currents in the two phases connected to it, and
+  its effective value is c [root]2, where c is the current of one phase.
+
+  [Illustration: FIG. 39.]
+
+  [Illustration: FIG. 40.]
+
+  [Illustration: FIG. 41.]
+
+
+    Three-phase alternators.
+
+  When we pass to machines giving three phases differing by 120°, the
+  same methods of star and mesh connexion find their analogies. If the
+  current in coil A (fig. 41) is flowing away from the centre, and has
+  its maximum value, the currents in coils B and C are flowing towards
+  the centre, and are each of half the magnitude of the current in A;
+  the algebraic sum of the currents is therefore zero, and this will
+  also be the case for all other instants. Hence the three coils can be
+  united together at the centre, and three external wires are alone
+  required. In this star or "Y" connexion, if e be the effective voltage
+  of each phase, or the voltage between any one of the three collecting
+  rings and the common connexion, the volts between any pair of
+  transmitting lines will be E = e [root]3 (fig. 41); if the load be
+  balanced, the effective current C in each of the three lines will be
+  equal, and the total output in watts will be W = 3Ce = 3CE/[root]3 =
+  1.732 EC, or 1.732 times the product of the effective voltage between
+  the lines and the current in any single line. Next, if the three coils
+  are closed upon themselves in a mesh or _delta_ fashion (fig. 42), the
+  three transmitting wires may be connected to the junctions of the
+  coils (by means of collecting rings if the armature rotates). The
+  voltage E between any pair of wires is evidently that generated by
+  one phase, and the current in a line wire is the resultant of that in
+  two adjacent phases; or in a balanced system, if c be the current in
+  each phase, the current in the line wire beyond a collecting ring is C
+  = c [root]3, hence the watts are W = 3cE = 3CE/[root]3 = 1.732 EC, as
+  before. Thus any three-phase winding may be changed over from the star
+  to the delta connexion, and will then give 1.732 times as much
+  current, but only 1/1.732 times the voltage, so that the output
+  remains the same.
+
+  [Illustration: FIG. 42.]
+
+
+    Armature reaction in alternators
+
+  The "armature reaction" of the alternator, when the term is used in
+  its widest sense to cover all the effects of the alternating current
+  in the armature as linked with a magnetic circuit or circuits, may be
+  divided into three items which are different in their origin and
+  consequences. In the first place the armature current produces a
+  self-induced flux in local circuits independent of the main magnetic
+  circuit, as e.g. linked with the ends of the coils as they project
+  outwards from the armature core; such lines may be called "secondary
+  leakage," of which the characteristic feature is that its amount is
+  independent of the position of the coils relatively to the poles. The
+  alternations of this flux give rise to an inductive voltage lagging
+  90° behind the phase of the current, and this leakage or reactance
+  voltage must be directly counterbalanced electrically by an equal
+  component in the opposite sense in the voltage from the main field.
+  The second and third elements are more immediately magnetic and are
+  entirely dependent upon the position of the coils in relation to the
+  poles and in relation to the phase of the current which they then
+  carry. When the side of a drum coil is immediately under the centre of
+  a pole, its ampere-turns are cross-magnetizing, i.e. produce a
+  distortion of the main flux, displacing its maximum density to one or
+  other edge of the pole. When the coil-side is midway between the poles
+  and the axes of coil and pole coincide, the coil stands exactly
+  opposite to the pole and embraces the same magnetic circuit as the
+  field-magnet coils; its turns are therefore directly magnetizing,
+  either weakening or strengthening the main flux according to the
+  direction of the current. In intermediate positions the ampere-turns
+  of the coil gradually pass from cross to direct and vice versa. When
+  the instantaneous values of either the cross or direct magnetizing
+  effect are integrated over a period and averaged, due account being
+  taken of the number of slots per coil-side and of the different phases
+  of the currents in the polyphase machine, expressions are obtained for
+  the equivalent cross and direct ampere-turns of the armature as acting
+  upon a pair of poles. For a given winding and current, the determining
+  factor in either the one or the other is found to be the relative
+  phase angle between the axis of a coil in its position when carrying
+  the maximum current and the centre of a pole, the transverse reaction
+  being proportional to the cosine of this angle, and the direct
+  reaction to its sine. If the external circuit is inductive, the
+  maximum value of the current lags behind the E.M.F. and so behind the
+  centre of the pole; such a negative angle of lag causes the direct
+  magnetizing turns to become back turns, directly weakening the main
+  field and lowering the terminal voltage. Thus, just as in the
+  continuous-current dynamo, for a given voltage under load the
+  excitation between the pole-pieces X_p must not only supply the net
+  excitation required over the air-gaps, armature core and teeth, but
+  must also balance the back ampere-turns X_b of the armature.
+
+  Evidently therefore the characteristic curve connecting armature
+  current and terminal volts will with a constant exciting current
+  depend on the nature of the load, whether inductive or non-inductive,
+  and upon the amount of inductance already possessed by the armature
+  itself. With an inductive load it will fall more rapidly from its
+  initial maximum value, or, conversely, if the initial voltage is to be
+  maintained under an increasing load, the exciting current will have to
+  be increased more than if the load were non-inductive. In practical
+  working many disadvantages result from a rapid drop of the terminal
+  E.M.F. under increasing load, so that between no load and full load
+  the variation in terminal voltage with constant excitation should not
+  exceed 15%. Thus the output of an alternator is limited either by its
+  heating or by its armature reaction, just as is the output of a
+  continuous-current dynamo; in the case of the alternator, however, the
+  limit set by armature reaction is not due to any sparking at the
+  brushes, but to the drop in terminal voltage as the current is
+  increased, and the consequent difficulty in maintaining a constant
+  potential on the external circuit.
+
+
+    The coupling of alternators.
+
+  The joint operation of several alternators so that their outputs may
+  be delivered into the same external circuit is sharply distinguished
+  from the corresponding problem in continuous-current dynamos by the
+  necessary condition that they must be in synchronism, i.e. not only
+  must they be so driven that their frequency is the same, but their
+  E.M.F.'s must be in phase or, as it is also expressed, the machines
+  must be in step. Although in practice it is impossible to run two
+  alternators in series unless they are rigidly coupled together--which
+  virtually reduces them to one machine--two or more machines can be run
+  in parallel, as was first described by H. Wilde in 1868 and
+  subsequently redemonstrated by J. Hopkinson and W.G. Adams in 1884.
+  Their E.M.F.'s should be as nearly as possible in synchronism, but,
+  as contrasted with series connexion, parallel coupling gives them a
+  certain power of recovery if they fall out of step, or are not in
+  exact synchronism when thrown into parallel. In such circumstances a
+  synchronizing current passes between the two machines, due to the
+  difference in their instantaneous pressures; and as this current
+  agrees in phase more nearly with the leading than with the lagging
+  machine, the former machine does work as a generator on the latter as
+  a motor. Hence the lagging machine is accelerated and the leading
+  machine is retarded, until their frequencies and phase are again the
+  same.
+
+
+  Uses of alternators.
+
+The chief use of the alternator has already been alluded to. Since it
+can be employed to produce very high pressures either directly or
+through the medium of transformers, it is specially adapted to the
+electrical transmission of energy over long distances.[22] In the early
+days of electric lighting, the alternate-current system was adopted for
+a great number of central stations; the machines, designed to give a
+pressure of 2000 volts, supplied transformers which were situated at
+considerable distances and spread over large areas, without an undue
+amount of copper in the transmitting lines. While there was later a
+tendency to return to the continuous current for central stations, owing
+to the introduction of better means for economizing the weight of copper
+in the mains, the alternating current again came into favour, as
+rendering it possible to place the central station in some convenient
+site far away from the district which it was to serve. The pioneer
+central station in this direction was the Deptford station of the London
+Electric Supply Corporation, which furnished current to the heart of
+London from a distance of 7 m. In this case, however, the alternators
+were single-phase and gave the high pressure of 10,000 volts
+immediately, while more recently the tendency has been to employ step-up
+transformers and a polyphase system. The advantage of the latter is that
+the current, after reaching the distant sub-stations, can be dealt with
+by rotary converters, through which it is transformed into a continuous
+current. The alternator is also used for welding, smelting in electric
+furnaces, and other metallurgical processes where heating effects are
+alone required; the large currents needed therein can be produced
+without the disadvantage of the commutator, and, if necessary,
+transformers can be interposed to lower the voltage and still further
+increase the current. The alternating system can thus meet very various
+needs, and its great recommendation may be said to lie in the
+flexibility with which it can supply electrical energy through
+transformers at any potential, or through rotary converters in
+continuous-current form.
+
+  AUTHORITIES.--For the further study of the dynamo, the following may
+  be consulted, in addition to the references already given:--
+
+  _General_: S.P. Thompson, _Dynamo-Electric
+  Machinery--Continuous-Current Machines_ (1904), _Alternating-Current
+  Machinery_ (1905, London); G. Kapp, _Dynamos, Alternators and
+  Transformers_ (London, 1893); _Id., Electric Transmission of Energy_
+  (London, 1894); Id., _Dynamo Construction; Electrical and Mechanical_
+  (London, 1899); H.F. Parshall and H.M. Hobart, _Electric Generators_
+  (London, 1900); C.C. Hawkins and F. Wallis, _The Dynamo_ (London,
+  1903); E. Arnold, _Konstruktionstafeln für den Dynamobau_ (Stuttgart,
+  1902); C.P. Steinmetz, _Elements of Electrical Engineering_ (New York,
+  1901).
+
+  _Continuous-Current Dynamos_: J. Fischer-Hinnen, _Continuous-Current
+  Dynamos_ (London, 1899); E. Arnold, _Die Gleichstrommaschine_ (Berlin,
+  1902); F. Niethammer, _Berechnung und Konstruktion der
+  Gleichstrommaschinen und Gleichstrommotoren_ (Stuttgart, 1904).
+
+  _Alternators_: D.C. Jackson and J.P. Jackson, _Alternating Currents
+  and Alternating Current Machinery_ (New York, 1903); J.A. Fleming,
+  _The Alternate Current Transformer_ (London, 1899); C.P. Steinmetz,
+  _Alternating Current Phenomena_ (New York, 1900); E. Arnold, _Die
+  Wechselstromtechnik_ (Berlin, 1904); S.P. Thompson, _Polyphase
+  Electric Currents_ (London, 1900); A. Stewart, _Modern Polyphase
+  Machinery_ (London, 1906); M. Oudin, _Standard Polyphase Apparatus and
+  Systems_ (New York, 1904).     (C. C. H.)
+
+
+FOOTNOTES:
+
+  [1] _Experimental Researches in Electricity_, series ii. § 6, pars.
+    256, 259-260, and series xxviii. § 34.
+
+  [2] _Ibid._ series i. § 4, pars. 84-90.
+
+  [3] "On the Physical Lines of Magnetic Force," _Phil. Mag._, June
+    1852.
+
+  [4] Faraday, _Exp. Res._ series xxviii. § 34, pars. 3104, 3114-3115.
+
+  [5] _Id._, ib. series i. § 4, pars. 114-119.
+
+  [6] _Id._, ib. series ii. § 6, pars. 211, 213; series xxviii. § 34,
+    par. 3152.
+
+  [7] Invented by Nikola Tesla (_Elec. Eng._ vol. xiii. p. 83. Cf.
+    Brit. Pat. Spec. Nos. 2801 and 2812, 1894). Several early inventors,
+    e.g. Salvatore dal Negro in 1832 (_Phil. Mag._ third series, vol. i.
+    p. 45), adopted reciprocating or oscillatory motion, and this was
+    again tried by Edison in 1878.
+
+  [8] The advantage to be obtained by making the poles closely embrace
+    the armature core was first realized by Dr Werner von Siemens in his
+    "shuttle-wound" armature (Brit. Pat. No. 2107, 1856).
+
+  [9] _Nuovo Cimento_ (1865), 19, 378.
+
+  [10] Brit. Pat. No. 1668 (1870); _Comptes rendus_ (1871), 73, 175.
+
+  [11] _Ann. Chim. Phys._ l. 322.
+
+  [12] Ibid. li. 76. Since in H. Pixii's machine the armature was
+    stationary, while both magnet and commutator rotated, four brushes
+    were used, and the arrangement was not so simple as the split-ring
+    described above, although the result was the same. J. Saxton's
+    machine (1833) and E.M. Clarke's machine (1835, see Sturgeon's
+    _Annals of Electricity_, i. 145) were similar to one another in that
+    a unidirected current was obtained by utilizing every alternate
+    half-wave of E.M.F., but the former still employed mercury collecting
+    cups, while the latter employed metal brushes. W. Sturgeon in 1835
+    followed Pixii in utilizing the entire wave of E.M.F., and abandoned
+    the mercury cups in favour of metal brushes pressing on four
+    semicircular disks (_Scientific Researches_, p. 252). The simple
+    split-ring is described by Sir C. Wheatstone and Sir W.F. Cooke in
+    their Patent No. 8345 (1840).
+
+  [13] By the "leading" side of the tooth or of an armature coil or
+    sector is to be understood that side which first enters under a pole
+    after passing through the interpolar gap, and the edge of the pole
+    under which it enters is here termed the "leading" edge as opposed to
+    the "trailing" edge or corner from under which a tooth or coil
+    emerges into the gap between the poles; cf. fig. 30, where the
+    leading and trailing pole-corners are marked ll and tt.
+
+  [14] Such was the arrangement of Wheatstone's machine (Brit. Pat. No.
+    9022) of 1841, which was the first to give a more nearly "continuous"
+    current, the number of sections and split-rings being five.
+
+  [15] Its development from the split-ring was due to Pacinotti and
+    Gramme (Brit. Pat. No. 1668, 1870) in connexion with their ring
+    armatures.
+
+  [16] And extended by G. Kapp, "On Modern Continuous-Current
+    Dynamo-Electric Machines," _Proc. Inst. C.E._ vol. lxxxiii. p. 136.
+
+  [17] Drs J. and E. Hopkinson, "Dynamo-Electric Machinery," Phil.
+    Trans., May 6, 1886; this was further expanded in a second paper on
+    "Dynamo-Electric Machinery," _Proc. Roy. Soc._, Feb. 15, 1892, and
+    both are reprinted in _Original Papers on Dynamo-Machinery and Allied
+    Subjects_.
+
+  [18] _Exp. Res._, series i. § 4, par. 111. In 1845 Wheatstone and
+    Cooke patented the use of "voltaic" magnets in place of permanent
+    magnets (No. 10,655).
+
+  [19] Between Moutiers and Lyons, a distance of 115 m., energy is
+    transmitted on the Thury direct-current system at a maximum pressure
+    of 60,000 volts. Four groups of machines in series are employed, each
+    group consisting of four machines in series; the rated output of each
+    component machine is 75 amperes at 3900 volts or 400 h.p. A water
+    turbine drives two pairs of such machines through an insulating
+    coupling, and the sub-base of each pair of machines is separately
+    insulated from earth, the foundation being also of special insulating
+    materials.
+
+  [20] For experiments on high-frequency currents, Nikola Tesla
+    constructed an alternator having 384 poles and giving a frequency of
+    about 10,000 (_Journ. Inst. Elec. Eng._ 1892, 21, p. 82). The
+    opposite extreme is found in alternators directly coupled to the
+    Parsons steam-turbine, in which, with a speed of 3000 revs. per min.,
+    only two poles are required to give a frequency of 50. By a
+    combination of a Parsons steam-turbine running at 12,000 revs. per
+    min. with an alternator of 140 poles a frequency of 14,000 has been
+    obtained (_Engineering_, 25th of August 1899). For description of an
+    experimental machine for 10,000 cycles per second when running at
+    3000 revs. per min., see _Trans. Amer. Inst. Elect. Eng._ vol. xxiii.
+    p. 417.
+
+  [21] As in the historical transmission of energy from Lauffen to
+    Frankfort (1891).
+
+  [22] In the pioneer three-phase transmission between Laufen and
+    Frankfort (_Electrician_, vol. xxvi. p. 637, and xxvii. p. 548), the
+    three-phase current was transformed up from about 55 to 8500 volts,
+    the distance being 110 m. A large number of installations driven by
+    water power are now at work, in which energy is transmitted on the
+    alternating-current system over distances of about 100 m. at
+    pressures ranging from 20,000 to 67,000 volts.
+
+
+
+
+DYNAMOMETER (Gr. [Greek: dynamis], strength, and [Greek: metron], a
+measure), an instrument for measuring force exerted by men, animals and
+machines. The name has been applied generally to all kinds of
+instruments used in the measurement of a force, as for example electric
+dynamometers, but the term specially denotes apparatus used in connexion
+with the measurement of work, or in the measurement of the horse-power
+of engines and motors. If P represent the average value of the component
+of a force in the direction of the displacement, s, of its point of
+application, the product Ps measures the work done during the
+displacement. When the force acts on a body free to turn about a fixed
+axis only, it is convenient to express the work done by the transformed
+product T[theta], where T is the average turning moment or torque acting
+to produce the displacement [theta] radians. The apparatus used to
+measure P or T is the dynamometer. The factors s or [theta] are observed
+independently. Apparatus is added to some dynamometers by means of which
+a curve showing the variations of P on a distance base is drawn
+automatically, the area of the diagram representing the work done; with
+others, integrating apparatus is combined, from which the work done
+during a given interval may be read off directly. It is convenient to
+distinguish between absorption and transmission dynamometers. In the
+first kind the work done is converted into heat; in the second it is
+transmitted, after measurement, for use.
+
+  _Absorption Dynamometers._--Baron Prony's dynamometer (_Ann. Chim.
+  Phys._ 1821, vol. 19), which has been modified in various ways,
+  consists in its original form of two symmetrically shaped timber beams
+  clamped to the engine-shaft. When these are held from turning, their
+  frictional resistance may be adjusted by means of nuts on the screwed
+  bolts which hold them together until the shaft revolves at a given
+  speed. To promote smoothness of action, the rubbing surfaces are
+  lubricated. A weight is moved along the arm of one of the beams until
+  it just keeps the brake steady midway between the stops which must be
+  provided to hold it when the weight fails to do so. The general theory
+  of this kind of brake is as follows:-Let F be the whole frictional
+  resistance, r the common radius of the rubbing surfaces, W the force
+  which holds the brake from turning and whose line of action is at a
+  perpendicular distance R from the axis of the shaft, N the revolutions
+  of the shaft per minute, [omega] its angular velocity in radians per
+  second; then, assuming that the adjustments are made so that the
+  engine runs steadily at a uniform speed, and that the brake is held
+  still, clear of the stops and without oscillation, by W, the torque T
+  exerted by the engine is equal to the frictional torque Fr acting at
+  the brake surfaces, and this is measured by the statical moment of the
+  weight W about the axis of revolution; that is--
+
+    T = Fr = WR.  (1)
+
+  Hence WR measures the torque T.
+
+  If more than one force be applied to hold the brake from turning, Fr,
+  and therefore T, are measured by the algebraical sum of their
+  individual moments with respect to the axis. If the brake is not
+  balanced, its moment about the axis must be included. Therefore, quite
+  generally,
+
+    T = [Sigma]WR.  (2)
+
+  The factor [theta] of the product T[theta] is found by means of a
+  revolution counter. The power of a motor is measured by the rate at
+  which it works, and this is expressed by T[omega] = T2[pi]N/60 in
+  foot-pounds per second, or T2[pi]N/33,000 in horse-power units. The
+  latter is commonly referred to as the "brake horse-power." The
+  maintenance of the conditions of steadiness implied in equation (1)
+  depends upon the constancy of F, and therefore of the coefficient of
+  friction µ between the rubbing surfaces. The heating at the surfaces,
+  the variations in their smoothness, and the variations of the
+  lubrication make [mu] continuously variable, and necessitate frequent
+  adjustment of W or of the nuts. J.V. Poncelet (1788-1867) invented a
+  form of Prony brake which automatically adjusted its grip as [mu]
+  changed, thereby maintaining F constant.
+
+  The principle of the compensating brake devised by J.G. Appold
+  (1800-1865) is shown in fig. 1. A flexible steel band, lined with wood
+  blocks, is gripped on the motor fly-wheel or pulley by a screw A,
+  which, together with W, is adjusted to hold the brake steady.
+  Compensation is effected by the lever L inserted at B. This has a
+  slotted end, engaged by a pin P fixed to the framing, and it will be
+  seen that its action is to slacken the band if the load tends to rise
+  and to tighten it in the contrary case. The external forces holding
+  the brake from turning are W, distant R from the axis, and the
+  reaction, W1 say, of the lever against the fixed pin P, distant R1
+  from the axis. The moment of W1 may be positive or negative. The
+  torque T at any instant of steady running is therefore {WR ± W1R1}.
+
+  [Illustration: FIG. 1.]
+
+  Lord Kelvin patented a brake in 1858 (fig. 2) consisting of a rope or
+  cord wrapped round the circumference of a rotating wheel, to one end
+  of which is applied a regulated force, the other end being fixed to a
+  spring balance. The ropes are spaced laterally by the blocks B, B, B,
+  B, which also serve to prevent them from slipping sideways. When the
+  wheel is turning in the direction indicated, the forces holding the
+  band still are W, and p, the observed pull on the spring balance. Both
+  these forces usually act at the same radius R, the distance from the
+  axis to the centre line of the rope, in which case the torque T is (W
+  - p)R, and consequently the brake horse-power is
+
+    (W - p)R × 2[pi]N
+    -----------------.
+          33,000
+
+  When µ changes the weight W rises or falls against the action of the
+  spring balance until a stable condition of running is obtained. The
+  ratio {W/p} is given by e^{µ[theta]}, where e = 2.718; µ is the
+  coefficient of friction and [theta] the angle, measured in radians,
+  subtended by the arc of contact between the rope and the wheel. In
+  fig. 2 [theta] = 2[pi]. The ratio W/p increases very rapidly as
+  [theta] is increased, and therefore, by making [theta] sufficiently
+  large, p may conveniently be made a small fraction of W, thereby
+  rendering errors of observation of the spring balance negligible. Thus
+  this kind of brake, though cheap to make, is, when [theta] is large
+  enough, an exceedingly accurate measuring instrument, readily applied
+  and easily controlled. It has come into very general use in recent
+  years, and has practically superseded the older forms of block brakes.
+
+  [Illustration: FIG. 2.]
+
+  It is sometimes necessary to use water to keep the brake wheel cool.
+  Engines specially designed for testing are usually provided with a
+  brake wheel having a trough-shaped rim. Water trickles continuously
+  into the trough, and the centrifugal action holds it as an inside
+  lining against the rim, where it slowly evaporates.
+
+  Fig. 3 shows a band-brake invented by Professor James Thomson,
+  suitable for testing motors exerting a constant torque (see
+  _Engineering_, 22nd October 1880). To maintain e^{µ[theta]} constant,
+  compensation for variation of [mu] is made by inversely varying
+  [theta]. A and B are fast and loose pulleys, and the brake band is
+  placed partly over the one and partly over the other. Weights W and w
+  are adjusted to the torque. The band turns with the fast pulley if
+  [mu] increase, thereby slightly turning the loose pulley, otherwise at
+  rest, until [theta] is adjusted to the new value of [mu]. This form of
+  brake was also invented independently by J.A.M.L. Carpentier, and the
+  principle has been used in the Raffard brake. A self-compensating
+  brake of another kind, by Marcel Deprez, was described with
+  Carpentier's in 1880 (_Bulletin de la société d'encouragement_,
+  Paris). W.E. Ayrton and J. Perry used a band or rope brake in which
+  compensation is effected by the pulley drawing in or letting out a
+  part of the band or rope which has been roughened or in which a knot
+  has been tied.
+
+  In an effective water-brake invented by W. Froude (see _Proc. Inst. M.
+  E._ 1877), two similar castings, A and B, each consisting of a boss
+  and circumferential annular channel, are placed face to face on a
+  shaft, to which B is keyed, A being free (fig. 4). A ring tube of
+  elliptical section is thus formed. Each channel is divided into a
+  series of pockets by equally spaced vanes inclined at 45°. When A is
+  held still, and B rotated, centrifugal action sets up vortex currents
+  in the water in the pockets; thus a continuous circulation is caused
+  between B and A, and the consequent changes of momentum give rise to
+  oblique reactions. The moments of the components of these actions and
+  reactions in a plane to which the axis of rotation is at right angles
+  are the two aspects of the torque acting, and therefore the torque
+  acting on B through the shaft is measured by the torque required to
+  hold A still. Froude constructed a brake to take up 2000 H.P. at 90
+  revs. per min. by duplicating this apparatus. This replaced the
+  propeller of the ship whose engines were to be tested, and the outer
+  casing was held from turning by a suitable arrangement of levers
+  carried to weighing apparatus conveniently disposed on the wharf. The
+  torque corresponding to 2000 H.P. at 90 revs. per min. is 116,772
+  foot-pounds, and a brake 5 ft. in diameter gave this resistance. Thin
+  metal sluices were arranged to slide between the wheel and casing, and
+  by their means the range of action could be varied from 300 H.P. at
+  120 revs. per min. to the maximum.
+
+  [Illustration: FIG. 3.]
+
+  [Illustration: FIG. 4.]
+
+  Professor Osborne Reynolds in 1887 patented a water-brake (see _Proc.
+  Inst. C.E._ 99, p. 167), using Froude's turbine to obtain the highly
+  resisting spiral vortices, and arranging passages in the casing for
+  the entry of water at the hub of the wheel and its exit at the
+  circumference. Water enters at E (fig. 5), and finds its way into the
+  interior of the wheel, A, driving the air in front of it through the
+  air-passages K, K. Then following into the pocketed chambers V1, V2,
+  it is caught into the vortex, and finally escapes at the
+  circumference, flowing away at F. The air-ways k, k, in the fixed
+  vanes establish communication between the cores of the vortices and
+  the atmosphere. From {1/5} to 30 H.P. may be measured at 100 revs. per
+  min. by a brake-wheel of this kind 18 in. in diameter. For other
+  speeds the power varies as the cube of the speed. The casing is held
+  from turning by weights hanging on an attached arm. The cocks
+  regulating the water are connected to the casing, so that any tilting
+  automatically regulates the flow, and therefore the thickness of the
+  film in the vortex. In this way the brake may be arranged to maintain
+  a constant torque, not withstanding variation of the speed. In G.I.
+  Alden's brake (see _Trans. Amer. Soc. Eng._ vol. xi.) the resistance
+  is obtained by turning a cast iron disk against the frictional
+  resistance of two thin copper plates, which are held in a casing free
+  to turn upon the shaft, and are so arranged that the pressure between
+  the rubbing surfaces is controlled, and the heat developed by friction
+  carried away, by the regulated flow of water through the casing. The
+  torque required to hold the casing still against the action of the
+  disk measures the torque exerted by the shaft to which the disk is
+  keyed.
+
+  [Illustration: Fig. 5.]
+
+  _Transmission Dynamometers._--The essential part of many transmission
+  dynamometers is a spring whose deformation indirectly measures the
+  magnitude of the force transmitted through it. For many kinds of
+  spring the change of form is practically proportional to the force,
+  but the relation should always be determined experimentally. General
+  A.J. Morin (see _Notice sur divers appareils dynamométriques_, Paris,
+  1841), in his classical experiments on traction, arranged his
+  apparatus so that the change in form of the spring was continuously
+  recorded on a sheet of paper drawn under a style. For longer
+  experiments he used a "Compteur" or mechanical integrator, suggested
+  by J.V. Poncelet, from which the work done during a given displacement
+  could be read off directly. This device consists of a roller of radius
+  r, pressed into contact with a disk. The two are carried on a common
+  frame, so arranged that a change in form of the spring causes a
+  relative displacement of the disk and roller, the point of contact
+  moving radially from or towards the centre of the disk. The radial
+  distance x is at any instant proportional to the force acting through
+  the spring. The angular displacement, [theta], of the disk is made
+  proportional to the displacement, s, of the point of application of
+  the force by suitable driving gear. If d[phi] is the angular
+  displacement of the roller corresponding to displacements, d[theta] of
+  the disk, and ds of the point of application of P, a, and C constants,
+  then
+
+             xd[theta]   a
+    d[phi] = --------- = -- P ds = C·P ds,
+                 r       r
+                           _
+                          /s2
+  and therefore [phi] = C |  P ds;
+                         _/s1
+
+  that is, the angular displacement of the roller measures the work done
+  during the displacement from s1 to s2. The shaft carrying the roller
+  is connected to a counter so that [phi] may be observed. The angular
+  velocity of the shaft is proportional to the rate of working. Morin's
+  dynamometer is shown in fig. 6. The transmitting spring is made up of
+  two flat bars linked at their ends. Their centres s1, s2, are held
+  respectively by the pieces A, B, which together form a sliding pair.
+  The block A carries the disk D, B carries the roller R and counting
+  gear. The pulley E is driven from an axle of the carriage. In a
+  dynamometer used by F.W. Webb to measure the tractive resistance of
+  trains on the London & North-Western railway, a tractive pull or push
+  compresses two spiral springs by a definite amount, which is recorded
+  to scale by a pencil on a sheet of paper, drawn continuously from a
+  storage drum at the rate of 3 in. per mile, by a roller driven from
+  one of the carriage axles. Thus the diagram shows the tractive force
+  at any instant. A second pencil electrically connected to a clock
+  traces a time line on the diagram with a kick at every thirty seconds.
+  A third pencil traces an observation line in which a kick can be made
+  at will by pressing any one of the electrical pushes placed about the
+  car, and a fourth draws a datum line. The spring of the dynamometer
+  car used by W. Dean on the Great Western railway is made up of thirty
+  flat plates, 7 ft. 6 in. long, 5 in. × 5/8 in. at the centre, spaced
+  by distance pieces nibbed into the plates at the centre and by rollers
+  at the ends. The draw-bar is connected to the buckle, which is carried
+  on rollers, the ends of the spring resting on plates fixed to the
+  under-frame. The gear operating the paper roll is driven from the axle
+  of an independent wheel which is let down into contact with the rail
+  when required. This wheel serves also to measure the distance
+  travelled. A Morin disk and roller integrator is connected with the
+  apparatus, so that the work done during a journey may be read off.
+  Five lines are traced on the diagram.
+
+  [Illustration: FIG. 6.]
+
+  In spring dynamometers designed to measure a transmitted torque, the
+  mechanical problem of ascertaining the change of form of the spring is
+  complicated by the fact that the spring and the whole apparatus are
+  rotating together. In the Ayrton and Perry transmission dynamometer or
+  spring coupling of this type, the relative angular displacement is
+  proportional to the radius of the circle described by the end of a
+  light lever operated by mechanism between the spring-connected parts.
+  By a device used by W.E. Dalby (_Proc. Inst. C.E._ 1897-1898, p. 132)
+  the change in form of the spring is shown on a fixed indicator, which
+  may be placed in any convenient position. Two equal sprocket wheels
+  Q1, Q2, are fastened, the one to the spring pulley, the other to the
+  shaft. An endless band is placed over them to form two loops, which
+  during rotation remain at the same distance apart, unless relative
+  angular displacement occurs between Q1 and Q2 (fig. 7) due to a change
+  in form of the spring. The change in the distance d is proportional to
+  the change in the torque transmitted from the shaft to the pulley. To
+  measure this, guide pulleys are placed in the loops guided by a
+  geometric slide, the one pulley carrying a scale, and the other an
+  index. A recording drum or integrating apparatus may be arranged on
+  the pulley frames. A quick variation, or a periodic variation of the
+  magnitude of the force or torque transmitted through the springs,
+  tends to set up oscillations, and this tendency increases the nearer
+  the periodic time of the force variation approaches a periodic time of
+  the spring. Such vibrations may be damped out to a considerable extent
+  by the use of a dash-pot, or may be practically prevented by using a
+  relatively stiff spring.
+
+  [Illustration: FIG. 7.]
+
+  Every part of a machine transmitting force suffers elastic
+  deformation, and the force may be measured indirectly by measuring the
+  deformation. The relation between the two should in all cases be found
+  experimentally. G.A. Hirn (see _Les Pandynamomètres_, Paris, 1876)
+  employed this principle to measure the torque transmitted by a shaft.
+  Signor Rosio used a telephonic method to effect the same end, and
+  mechanical, optical and telephonic devices have been utilized by the
+  Rev. F.J. Jervis-Smith. (See _Phil. Mag._ February 1898.)
+
+  H. Frahm,[1] during an important investigation on the torsional
+  vibration of propeller shafts, measured the relative angular
+  displacement of two flanges on a propeller shaft, selected as far
+  apart as possible, by means of an electrical device (_Engineering_,
+  6th of February 1903). These measurements were utilized in combination
+  with appropriate elastic coefficients of the material to find the
+  horse-power transmitted from the engines along the shaft to the
+  propeller. In this way the effective horse-power and also the
+  mechanical efficiency of a number of large marine engines, each of
+  several thousand horse-power, have been determined.
+
+  [Illustration: FIG. 8.]
+
+  When a belt, in which the maximum and minimum tensions are
+  respectively P and p lb., drives a pulley, the torque exerted is (P -
+  p)r lb. ft., r being the radius of the pulley plus half the thickness
+  of the belt. P and p may be measured directly by leading the belt
+  round two freely hanging guide pulleys, one in the tight, the other in
+  the slack part of the belt, and adjusting loads on them until a stable
+  condition of running is obtained. In W. Froude's belt dynamometer (see
+  _Proc. Inst. M.E._, 1858) (fig. 8) the guide pulleys G1, G2 are
+  carried upon an arm free to turn about the axis O. H is a pulley to
+  guide the approaching and receding parts of the belt to and from the
+  beam in parallel directions. Neglecting friction, the unbalanced
+  torque acting on the beam is 4r{P - p} lb. ft. If a force Q acting at
+  R maintains equilibrium, QR/4 = (P - p)r = T. Q is supplied by a
+  spring, the extensions of which are recorded on a drum driven
+  proportionally to the angular displacement of the driving pulley; thus
+  a work diagram is obtained. In the Farcot form the guide pulleys are
+  attached to separate weighing levers placed horizontally below the
+  apparatus. In a belt dynamometer built for the Franklin Institute from
+  the designs of Tatham, the weighing levers are separate and arranged
+  horizontally at the top of the apparatus. The weighing beam in the
+  Hefner-Alteneck dynamometer is placed transversely to the belt (see
+  _Electrotechnischen Zeitschrift_, 1881, 7). The force Q, usually
+  measured by a spring, required to maintain the beam in its central
+  position is proportional to (P - p). If the angle [theta]1 = [theta]2
+  = 120°, Q = (P - p) neglecting friction.
+
+  When a shaft is driven by means of gearing the driving torque is
+  measured by the product of the resultant pressure P acting between the
+  wheel teeth and the radius of the pitch circle of the wheel fixed to
+  the shaft. Fig. 9, which has been reproduced from J. White's _A New
+  Century of Inventions_ (Manchester, 1822), illustrates possibly the
+  earliest application of this principle to dynamometry. The wheel D,
+  keyed to the shaft overcoming the resistance to be measured, is driven
+  from wheel N by two bevel wheels L, L, carried in a loose pulley K.
+  The two shafts, though in a line, are independent. A torque applied to
+  the shaft A can be transmitted to D, neglecting friction, without
+  change only if the central pulley K is held from turning; the torque
+  required to do this is twice the torque transmitted.
+
+  [Illustration: FIG. 9.]
+
+  The torque acting on the armature of an electric motor is necessarily
+  accompanied by an equal and opposite torque acting on the frame. If,
+  therefore, the motor is mounted on a cradle free to turn about
+  knife-edges, the reacting torque is the only torque tending to turn
+  the cradle when it is in a vertical position, and may therefore be
+  measured by adjusting weights to hold the cradle in a vertical
+  position. The rate at which the motor is transmitting work is then
+  T2[pi]n/550 H.P., where n is the revolutions per second of the
+  armature.
+
+  See James Dredge, _Electric Illumination_, vol. ii. (London, 1885);
+  W.W. Beaumont, "Dynamometers and Friction Brakes," _Proc. Inst. C.E._
+  vol. xcv. (London, 1889); E. Brauer, "Über Bremsdynamometer and
+  verwandte Kraftmesser," _Zeitschrift des Vereins deutscher Ingenieure_
+  (Berlin, 1888); J.J. Flather, _Dynamometers and the Measurement of
+  Power_ (New York, 1893).     (W. E. D.)
+
+
+FOOTNOTE:
+
+  [1] H. Frahm, "Neue Untersuchungen über die dynamischen Vorgänge in
+    den Wellenleitungen von Schiffsmaschinen mit besonderer
+    Berücksichtigung der Resonanzschwingungen," _Zeitschrift des Vereins
+    deutscher Ingenieure_, 31st May 1902.
+
+
+
+
+DYNASTY (Gr. [Greek: dynasteia], sovereignty, the position of a [Greek:
+dynastês], lord, ruler, from [Greek: dynasthai], to be able, [Greek:
+dynamis], power), a family or line of rulers, a succession of sovereigns
+of a country belonging to a single family or tracing their descent to a
+common ancestor. The term is particularly used in the history of ancient
+Egypt as a convenient means of arranging the chronology.
+
+
+
+
+DYSART, a royal and police burgh and seaport of Fifeshire, Scotland, on
+the shore of the Firth of Forth, 2 m. N.E. of Kirkcaldy by the North
+British railway. Pop. (1901) 3562. It has a quaint old-fashioned
+appearance, many ancient houses in High Street bearing inscriptions and
+dates. The public buildings include a town hall, library, cottage
+hospital, mechanics' institute and memorial hall. Scarcely anything is
+left of the old chapel dedicated to St Dennis, which for a time was used
+as a smithy; and of the chapel of St Serf, the patron saint of the
+burgh, only the tower remains. The chief industries are the manufacture
+of bed and table linen, towelling and woollen cloth, shipbuilding and
+flax-spinning. There is a steady export of coal, and the harbour is
+provided with a wet dock and patent slip. In smuggling days the "canty
+carles" of Dysart were professed "free traders." In the 15th and 16th
+centuries the town was a leading seat of the salt industry ("salt to
+Dysart" was the equivalent of "coals to Newcastle"), but the salt-pans
+have been abandoned for a considerable period. Nail-making, once famous,
+is another extinct industry. During the time of the alliance between
+Scotland and Holland, which was closer in Fifeshire than in other
+counties, Dysart became known as Little Holland. To the west of the town
+is Dysart House, the residence of the earl of Rosslyn. With Burntisland
+and Kinghorn Dysart forms one of the Kirkcaldy district group of
+parliamentary burghs. The town is mentioned as early as 874 in connexion
+with a Danish invasion. Its name is said to be a corruption of the Latin
+_desertum_, "a desert," which was applied to a cave on the seashore
+occupied by St Serf. In the cave the saint held his famous colloquy with
+the devil, in which Satan was worsted and contemptuously dismissed. From
+James V. the town received the rights of a royal burgh. In 1559 it was
+the headquarters of the Lords of the Congregation, and in 1607 the scene
+of the meetings of the synod of Fife known as the Three Synods of
+Dysart. Ravensheugh Castle, on the shore to the west of the town, is the
+Ravenscraig of Sir Walter Scott's ballad of "Rosabelle."
+
+William Murray, a native of the place, was made earl of Dysart in 1643,
+and his eldest child and heir, a daughter, Elizabeth, obtained in 1670 a
+regrant of the title, which passed to the descendants of her first
+marriage with Sir Lionel Tollemache, Bart., of Helmingham; she married
+secondly the 1st duke of Lauderdale, but had no children by him, and
+died in 1698. This countess of Dysart (afterwards duchess of Lauderdale)
+was a famous beauty of the period, and notorious both for her amours and
+for her political influence. She was said to have been the mistress of
+Oliver Cromwell, and also of Lauderdale before her first husband's
+death, and was a leader at the court of Charles II. Wycherley is
+supposed to have aimed at her in his Widow Blackacre in the _Plain
+Dealer_. Her son, Lionel Tollemache (d. 1727), transmitted the earldom
+to his grandson Lionel (d. 1770), whose sons Lionel (d. 1799) and
+Wilbraham (d. 1821) succeeded; they died without issue, and their sister
+Louisa (d. 1840), who married John Manners, an illegitimate son of the
+second son of the 2nd duke of Rutland, became countess in her own right,
+being succeeded by her grandson (d. 1878), and his grandson, the 8th
+earl.
+
+The earldom of Dysart must not be confounded with that of Desart
+(Irish), created (barony 1733) in 1793, and held in the Cuffe family,
+who were originally of Creech St Michael, Somerset, the Irish branch
+dating from Queen Elizabeth's time.
+
+
+
+
+DYSENTERY (from the Gr. prefix [Greek: dys]-, in the sense of "bad," and
+[Greek: enteron], the intestine), also called "bloody flux," an
+infectious disease with a local lesion in the form of inflammation and
+ulceration of the lower portion of the bowels. Although at one time a
+common disease in Great Britain, dysentery is now very rarely met with
+there, and is for the most part confined to warm countries, where it is
+the cause of a large amount of mortality. (For the pathology see
+DIGESTIVE ORGANS.)
+
+Recently considerable advance has been made in our knowledge of
+dysentery, and it appears that there are two distinct types of the
+disease: (1) amoebic dysentery, which is due to the presence of the
+amoeba histolytica (of Schaudinn) in the intestine; (2) bacillary
+dysentery, which has as causative agent two separate bacteria, (a) that
+discovered by Shiga in Japan, (b) that discovered by Flexner in the
+Philippine Islands. With regard to the bacillary type, at first both
+organisms were considered to be identical, and the name _bacillus
+dysenteriae_ was given to them; but later it was shown that these
+bacilli are different, both in regard to their cultural characteristics
+and also in that one (Shiga) gives out a soluble toxin, whilst the
+other has so far resisted all efforts to discover it. Further, the
+serum of a patient affected with one of the types has a marked
+agglutinative power on the variety with which he is infected and not on
+the other.
+
+Clinically, dysentery manifests itself with varying degrees of
+intensity, and it is often impossible without microscopical examination
+to determine between the amoebic and bacillary forms. In well-marked
+cases the following are the chief symptoms. The attack is commonly
+preceded by certain premonitory indications in the form of general
+illness, loss of appetite, and some amount of diarrhoea, which gradually
+increases in severity, and is accompanied with griping pains in the
+abdomen (tormina). The discharges from the bowels succeed each other
+with great frequency, and the painful feeling of pressure downwards
+(tenesmus) becomes so intense that the patient is constantly desiring to
+defecate. The matters passed from the bowels, which at first resemble
+those of ordinary diarrhoea, soon change their character, becoming
+scanty, mucous or slimy, and subsequently mixed with, or consisting
+wholly of, blood, along with shreds of exudation thrown off from the
+mucous membrane of the intestine. The evacuations possess a peculiarly
+offensive odour characteristic of the disease. Although the
+constitutional disturbance is at first comparatively slight, it
+increases with the advance of the disease, and febrile symptoms come on
+attended with urgent thirst and scanty and painful flow of urine. Along
+with this the nervous depression is very marked, and the state of
+prostration to which the patient is reduced can scarcely be exceeded.
+Should no improvement occur death may take place in from one to three
+weeks, either from repeated losses of blood, or from gradual exhaustion
+consequent on the continuance of the symptoms, in which case the
+discharges from the bowels become more offensive and are passed
+involuntarily.
+
+When, on the other hand, the disease is checked, the signs of
+improvement are shown in the cessation of the pain, in the evacuations
+being less frequent and more natural, and in relief from the state of
+extreme depression. Convalescence is, however, generally slow, and
+recovery may be imperfect--the disease continuing in a chronic form,
+which may exist for a variable length of time, giving rise to much
+suffering, and not unfrequently leading to an ultimately fatal result.
+
+The dysentery poison appears to exert its effects upon the glandular
+structures of the large intestine, particularly in its lower part. In
+the milder forms of the disease there is simply a congested or inflamed
+condition of the mucous membrane, with perhaps some inflammatory
+exudation on its surface, which is passed off by the discharges from the
+bowels. But in the more severe forms ulceration of the mucous membrane
+takes place. Commencing in and around the solitary glands of the large
+intestine in the form of exudations, these ulcers, small at first,
+enlarge and run into each other, till a large portion of the bowel may
+be implicated in the ulcerative process. Should the disease be arrested
+these ulcers may heal entirely, but occasionally they remain, causing
+more or less disorganization of the coats of the intestines, as is often
+found in chronic dysentery. Sometimes, though rarely, the ulcers
+perforate the intestines, causing rapidly fatal inflammation of the
+peritoneum, or they may erode a blood vessel and produce violent
+haemorrhage. Even where they undergo healing they may cause such a
+stricture of the calibre of the intestinal canal as to give rise to the
+symptoms of obstruction which ultimately prove fatal. One of the
+severest complications of the disease is abscess of the liver, usually
+said to be solitary, and known as tropical abscess of the liver, but
+probably is more frequently multiple than is usually thought.
+
+_Treatment._--Where the disease is endemic or is prevailing
+epidemically, it is of great importance to use all preventive measures,
+and for this purpose the avoidance of all causes likely to precipitate
+an attack is to be enjoined. Exposure to cold after heat, the use of
+unripe fruit, and intemperance in eating and drinking should be
+forbidden; and the utmost care taken as to the quality of the food and
+drinking water. In houses or hospitals where cases of the disease are
+under treatment, disinfectants should be freely employed, and the
+evacuations of the patients removed as speedily as possible, having
+previously been sterilized in much the same manner as is employed in
+typhoid fever. In the milder varieties of this complaint, such as those
+occurring sporadically, and where the symptoms are probably due to
+matters in the bowels setting up the dysenteric irritation, the
+employment of diaphoretic medicines is to be recommended, and the
+administration of such a laxative as castor oil, to which a small
+quantity of laudanum has been added, will often, by removing the source
+of the mischief, arrest the attack; but a method of treatment more to be
+recommended is the use of salines in large doses, such as one drachm of
+sodium sulphate from four to eight times a day. This treatment may with
+advantage be combined with the internal administration of ipecacuanha,
+which still retains its reputation in this disease. Latterly, free
+irrigation of the bowel with astringents, such as silver nitrate,
+tannalbin, &c., has been attended with success in those cases which have
+been able to tolerate the injections. In many instances they cannot be
+used owing to the extreme degree of irritability of the bowel. The
+operation of appendicostomy, or bringing the appendix to the surface and
+using it as the site for the introduction of the irrigating fluid, has
+been attended with considerable success.
+
+In those cases due to Shiga's bacillus the ideal treatment has been put
+at our disposal by the preparation of a specific antitoxin; this has
+been given a trial in several grave epidemics of late, and may be said
+to be the most satisfactory treatment and offer the greatest hope of
+recovery. It is also of great use as a prophylactic.
+
+The preparations of morphia are of great value in the symptomatic
+treatment of the disease. They may be applied externally as
+fomentations, for the relief of tormina; by rectal injection for the
+relief of the tenesmus and irritability of the bowel; hypodermically in
+advanced cases, for the relief of the general distress. In amoebic
+dysentery, warm injections of quinine _per rectum_ have proved very
+efficacious, are usually well tolerated, and are not attended with any
+ill effects. The diet should be restricted, consisting chiefly of soups
+and farinaceous foods; more especially is this of importance in the
+chronic form. For the thirst ice may be given by the mouth. Even in the
+chronic forms, confinement to bed and restriction of diet are the most
+important elements of the treatment. Removal from the hot climate and
+unhygienic surroundings must naturally be attended to.
+
+  BIBLIOGRAPHY.--Allbutt and Rolleston, _System of Medicine_, vol. ii.
+  part ii. (1907), "Dysentery," Drs Andrew Davidson and Simon Flexner;
+  Davidson, _Hygiene and Diseases of Warm Climates_ (Edinburgh, 1903);
+  Fearnside in _Ind. Med. Gaz._ (July 1905); Ford in _Journal of
+  Tropical Medicine_ (July 15, 1904); Korentchewsky in _Bulletin de
+  l'Institut Pasteur_ (February 1905); Shiga: Osier and M'Crae's _System
+  of Medicine_, vol. ii. p. 781 (1907); Skschivan and Stefansky in
+  _Berliner klinische Wochenschrift_ (February 11, 1907); Vaillard and
+  Dopter, on the treatment by antidysenteric serum, _Annales de
+  l'Institut Pasteur_, No. 5, p. 326 (1906); J.A. Pottinger,
+  "Appendicostomy in Chronic Dysentery," _Lancet_ (December 28, 1907);
+  Robert Doerr, _Das Dysenterietoxin_ (Gustav Fischer, Jena, 1907); F.M.
+  Sandwith, "Hunterian Lecture on the Treatment of Dysentery," _Lancet_
+  (December 7, 1907).
+
+
+
+
+DYSPEPSIA (from the Gr. prefix [Greek: dys-], hard, ill, and [Greek:
+peptein], to digest), or indigestion, a term vaguely given to a group of
+pathological symptoms. There are comparatively few diseases of any
+moment where some of the phenomena of dyspepsia are not present as
+associated symptoms, and not infrequently these exist to such a degree
+as to mask the real disease, of which they are only complications. This
+is especially the case in many organic diseases of the alimentary canal,
+in which the symptoms of dyspepsia are often the most prominent. In its
+restricted meaning, however (and it is to this that the present article
+applies), the term is used to describe a functional derangement of the
+natural process of digestion, apart from any structural change in the
+organs concerned in the act.
+
+The causes of this trouble may be divided into (a) those which concern
+the food, and (b) those which concern the organism. Among the causes
+connected with the food are not only the indulgence in indigestible
+articles of diet, but the too common practice of eating too much of
+what may be otherwise quite wholesome and digestible; and irregular, too
+frequent or too infrequent meals. The quantity of food required by
+different individuals varies between wide limits, but also the quantity
+required by the same individual varies considerably according to
+circumstances, more food being needed in cold than in warm weather, and
+more in an active open-air occupation than in a sedentary one. The
+thorough mastication of the food is a very important precursor of
+digestion,[1] and this only too often fails, either owing to haste over
+meals or because of painful or deficient teeth. Again, the quality of
+the food is of importance, some kinds of flesh being harder and more
+difficult of mastication than others. This is especially the case with
+meat that has been smoked or salted, and with that cooked too soon after
+the death of the animal. Drinks are a common source of dyspepsia. Beer
+when new and its fermentation not completed is especially bad. Vinegar
+and acid wines, if taken in large quantities, tend to produce gastric
+catarrh, and tea is a very fruitful source of this trouble. Even too
+much water at meal-times may cause indigestion, since the food in the
+mouth is apt to be softened by the water instead of saliva, and also the
+gastric juice becomes unduly diluted, rendering the digestion in the
+stomach too slow and prolonged. Carious teeth and oral sepsis, from
+whatsoever cause, lead to the same trouble.
+
+Of the causes which concern the organism, nervous influences come first.
+Bad news may take away all power of digestion and even provoke vomiting,
+and any worry or mental trouble tends to bring on this condition.
+General weakness and atony of the body affects the stomach in like
+degree, and, if the muscles of the abdominal wall be much wasted, they
+become too weak to support the abdominal viscera in place. Hence results
+a general tendency for these organs to fall, giving rise to a condition
+of visceroptosis, of which an obstinate dyspepsia is a very marked
+feature. Adhesions of the intestines from old inflammatory troubles,
+floating kidney and bad circulation may each be a cause of painful
+digestion. Again, a dyspepsia that will not yield to treatment is often
+one of the symptoms of renal disease, or, in young people of fifteen to
+twenty years of age, it may be the earliest sign of a gouty diathesis,
+or even of a more serious condition still--incipient phthisis. Chronic
+dyspepsia, by weakening the organism, renders it more liable to fall a
+prey to the attacks of the tubercle bacillus, but, on the other hand,
+the tuberculous lesion in the lung is often accompanied by a most
+intractable form of dyspepsia. From this it is clear that any condition
+which lessens the general well-being of the organism as a whole, apart
+from its producing any permanent morbid condition in the stomach, may
+yet interfere with the normal digestive processes and so give rise to
+dyspepsia.
+
+The symptoms of dyspepsia, even when due to a like cause, are so
+numerous and diversified in different individuals that probably no
+description could exactly represent them as they occur in any given
+case. All that can be here attempted is to mention some of the more
+prominent morbid phenomena usually present in greater or less degree.
+
+Very briefly, a furred tongue, foul breath, disturbance of appetite,
+nausea and vomiting, oppression in the chest, pain, flatulence and
+distension, acidity, pyrosis and constipation or diarrhoea are a few of
+the commonest symptoms.
+
+When the attack is dependent on some error in diet, and the dyspepsia
+consequently more of an acute character, there is often pain followed
+with sickness and vomiting of the offensive matters, after which the
+patient soon regains his former healthy state. What are commonly known
+as "bilious attacks" are frequently of this character. In the more
+chronic cases of dyspepsia the symptoms are somewhat different. A
+sensation of discomfort comes on shortly after a meal, and is more of
+the nature of weight and distension in the stomach than of actual pain,
+although this too may be present. These feelings may come on after each
+meal, or only after certain meals, and they may arise irrespective of
+the kind of food taken, or only after certain articles of diet. As in
+most of such cases the food is long retained in the stomach, it is apt
+to undergo fermentive changes, one of the results of which is the
+accumulation of gases which cause flatulence and eructations of an acid
+or foul character. Occasionally quantities of hot, sour, tasteless or
+bitter fluid--pyrosis--or mouthfuls of half-digested food, regurgitate
+from the stomach. Temporary relief may be obtained when another meal is
+taken, but soon the uncomfortable sensations return as before. The
+appetite may be craving or deficient, or desirous of abnormal kinds of
+food. The tongue registers the gastric condition with great delicacy;--a
+pasty white fur on the tongue is considered a sign of weakness or atony
+of the digestive tract; a clean pointed tongue with large papillae, and
+rather red at the edges and tip, is a sign of gastric irritation; and a
+pale flabby tongue suggests the need of stimulating treatment.
+Constipation is more common in the chronic forms of dyspepsia, diarrhoea
+in the acute.
+
+Numerous disagreeable and painful sensations in other parts are
+experienced, and are indeed often more distressing than the merely
+gastric symptoms. Pains in the chest, shortness of breathing,
+palpitation, headache, giddiness, affections of vision, coldness of the
+extremities, and general languor are common accompaniments of dyspepsia;
+while the nervous phenomena are specially troublesome in the form of
+sleeplessness, irritability, despondency and hypochondriasis.
+
+As regards _treatment_ only a few general observations can be made. The
+careful arrangement of the diet is a matter of first importance.
+Quantity must be regulated by the digestive capabilities of the
+individual, his age, and the demands made upon his strength by work.
+There is little doubt that the danger is in most instances on the side
+of excess, and the rule which enjoins the cessation from eating before
+the appetite is satisfied is a safe one for dyspeptics. Due time, too,
+must be given for the digestion of a meal, and from four to six hours
+are in general required for this purpose. Long fasts, however, are
+nearly as hurtful as too frequent meals. Of no less importance is the
+kind of food taken, and on this point those who suffer from indigestion
+must ever exercise the greatest care. It must be borne in mind that
+idiosyncrasy often plays an important part in digestion, some persons
+being unable to partake without injury of substances which are generally
+regarded as wholesome and digestible. In most cases it is found very
+helpful to separate the protein from the farinaceous food, and the more
+severe the dyspepsia the more thoroughly should this be done, only
+relaxing as the dyspepsia yields. No fluid should be drunk at
+meal-times, but from one to two tumblers of hot water should be drunk
+from an hour to an hour and a half before food. This washes any remnant
+of the last meal from the stomach, and also supplies material for the
+free secretion of saliva and gastric juice, thus promoting and
+accelerating digestion. The only exception to this is in the case of a
+dilated stomach, when it is wholly contra-indicated. With regard to
+mastication, Sir Andrew Clark's rule is a very good one, and is more
+easily followed than the ideal theory laid down by Horace Fletcher,
+according to whom any food is digestible if properly treated while still
+in the mouth. Clark's rule is that as the mouth normally contains
+thirty-two teeth, thirty-two bites should be given before the food is
+swallowed. This, of course, is a practical doctor's concession to human
+weakness. Mr Fletcher would train every one to "chew" till the contents
+of the mouth were swallowed by reflex action without deliberate act; and
+he applies this theory of mastication and salivation also to drinks
+(except water). Again, a lack of warmth being a source of dyspepsia,
+this should be attended to, the back of the neck, the front of the
+abdomen and the feet being the parts that require special attention. The
+feet should be raised on a stool, the ankles protected with warm
+stockings and a woollen "cummerbund" wound two or three times round the
+body. Experience has shown that in this complaint no particular kind of
+food or avoidance of food is absolutely to be relied on, but that in
+general the best diet is one of a mixed animal and vegetable kind,
+simply but well cooked. The partaking of many dishes, of highly-seasoned
+or salted meats, raw vegetables, newly-baked bread, pastry and
+confectionery are all well-known common causes of dyspepsia, and should
+be avoided. When even the simple diet usually taken is found to
+disagree, it may be necessary to change it temporarily for a still
+lighter form, such as a milk diet, and that even in very moderate
+quantity.
+
+The employment of alcoholic stimulants to assist digestion is largely
+resorted to, both with and without medical advice. While it seems
+probable that in certain cases of atonic dyspepsia, particularly in the
+feeble and aged, the moderate administration of alcohol has the effect
+of stimulating the secretion of gastric juice, and is an important
+adjuvant to other remedies, the advantages of its habitual use as an aid
+to digestion by the young and otherwise healthy, is more than
+questionable, and it will generally be found that among them, those are
+least troubled with indigestion who abstain from it. Rest should be
+taken both before and after food, and general hygienic measures are
+highly important, since whatever improves the state of the health will
+have a favourable influence on digestion. Hence regular exercise in the
+open air, early rising and the cold bath are to be strongly recommended.
+
+The medicinal treatment of dyspepsia can only be undertaken by a
+physician, but the following is a very brief résumé of the drugs he
+depends on to-day. Bicarbonate of soda with some bitter, as quassia,
+gentian or columba, is much in vogue as a direct gastric stimulant. In
+irritable dyspepsia some form of bismuth in solution or powder; and, to
+assist digestion through the nervous system, nux vomica and strychnine
+can be relied on. To give directly digestive material, hydrochloric
+acid, pepsin and rennet are prescribed in many forms, but where there is
+much vomiting ingluvin is more efficacious than pepsin. When farinaceous
+food is badly borne, diastase is helpful, given either before or with
+the meal. To prevent fermentation, phenol, creasote and sulpho-carbolate
+of soda are all extremely useful in skilled hands; and for intestinal
+decomposition and flatulent distension, bismuth salicylate with salol or
+ß-naphthol is much used. Cyllin, and charcoal in many forms, may be
+taken both for gastric and intestinal flatulence. But all these drugs,
+of proved value though they are, must be modified and combined to suit
+the special idiosyncrasy of the patient, and are therefore often worse
+than useless in inexperienced hands. The condition of the bowels must
+always have due attention.
+
+  See also DIGESTIVE ORGANS; NUTRITION and DIETETICS.
+
+
+FOOTNOTE:
+
+  [1] This aspect of the matter--"buccal digestion"--has been specially
+    emphasized in recent years by Horace Fletcher of the United States,
+    whose experience of the results of systematic "chewing," confirmed by
+    Sir M. Foster, Prof. Chittenden and others, has almost revolutionized
+    the science of dietetics.
+
+
+
+
+DYSTELEOLOGY, a modern word invented by Haeckel (_Evolution of Man_) for
+the doctrine of purposelessness, as opposed to the philosophical
+doctrine of design (Teleology).
+
+
+
+
+DZUNGARIA, DSONGARIA, or JUNGARIA, a former Mongolian kingdom of Central
+Asia, raised to its highest pitch by Kaldan or Bushtu Khan in the latter
+half of the 17th century, but completely destroyed by Chinese invasion
+about 1757-1759. It has played an important part in the history of
+Mongolia and the great migrations of Mongolian stems westward. Now its
+territory belongs partly to the Chinese empire (east Turkestan and
+north-western Mongolia) and partly to Russian Turkestan (provinces of
+Semiryechensk and Semipalatinsk). It derived its name from the Dsongars,
+or Songars, who were so called because they formed the left wing
+(_dson_, left; _gar_, hand) of the Mongolian army. Its widest limit
+included Kashgar, Yarkand, Khotan, the whole region of the T'ien Shan,
+or Tian-shan, Mountains, and in short the greater proportion of that
+part of Central Asia which extends from 35° to 50° N. and from 72° to
+97° E. The name, however, is more properly applied only to the present
+Chinese province of T'ien Shan-pei-lu and the country watered by the
+Ili. As a political or geographical term it has practically disappeared
+from the map; but the range of mountains stretching north-east along the
+southern frontier of the Land of the Seven Streams, as the district to
+the south-east of the Balkhash Lake is called, preserves the name of
+Dzungarian Range.
+
+
+
+
+E The fifth symbol in the English alphabet occupies also the same
+position in Phoenician and in the other alphabets descended from
+Phoenician. As the Semitic alphabet did not represent vowels, E was
+originally an aspirate. Its earliest form, while writing is still from
+right to left, is [symbol], the upright being continued some distance
+below the lowest of the cross-strokes. In some of the Greek alphabets it
+appears as [symbol] with the upright prolonged at both top and bottom,
+but it soon took the form with which we are familiar, though in the
+earlier examples of this form the cross-strokes are not horizontal but
+drop at an angle, [symbol]. In Corinth and places under its early
+influence like Megara, or colonized from it like Corcyra, the symbol for
+_e_ takes the form [symbol] or [symbol], while at Sicyon in the 6th and
+5th centuries B.C. it is represented by [symbol]. In early Latin it was
+sometimes represented by two perpendicular strokes of equal length,
+[symbol].
+
+In the earliest Greek inscriptions and always in Latin the symbol E
+represented both the short and the long _e_-sound. In Greek also it was
+often used for the close long sound which arose either by contraction of
+two short _e_-sounds or by the loss of a consonant, after a short
+_e_-sound, as in [Greek: phileite], "you love," for [Greek: phileete],
+and [Greek: phaeinos], "bright," out of an earlier [Greek: phaesnos].
+The Ionian Greeks of Asia Minor, who had altogether lost the aspirate,
+were the first to use the symbol H for the long _e_-sound, and in
+official documents at Athens down to 403 B.C., when the Greek alphabet
+as still known was adopted by the state, E represented [epsilon], [eta]
+and the sound arising by contraction or consonant loss as mentioned
+above which henceforth was written with two symbols, [Greek: ei], and
+being really a single sound is known as the "spurious diphthong." There
+were some minor distinctions in usage of the symbols E and H which need
+not here be given in detail. The ancient Greek name was [Greek: ei], not
+_Epsilon_ as popularly supposed; the names of the Greek letters are
+given from Kallias, an earlier contemporary of Euripides, in Athenaeus
+x. p. 453 d.
+
+In Greek the short _e_-sound to which E was ultimately limited was a
+close sound inclining more towards _i_ than _a_; hence the
+representation of the contraction of [Greek: ee] by [Greek: ei]. Its
+value in Latin was exactly the opposite, the Latin short _e_ being open,
+and the long close. In English there has been a gradual narrowing of the
+long vowels, _a_ becoming approximately _ei_ and _e_ becoming _i_
+(Sweet, _History of English Sounds_, §§ 781, 817 ff. 2nd ed.). In
+languages where the diphthong _ai_ has become a monophthong, the
+resulting sound is some variety of long _e_. Often the gradual
+assimilation can be traced through the intermediate stage of _ae_ to
+_e_, as in the Old Latin _aidilis_, which in classical Latin is
+_aedilis_, and in medieval MSS. _edilis_.
+
+The variety of spelling in English for the long and short _e_-sounds is
+conveniently illustrated in Miss Soames's _Introduction to the Study of
+Phonetics_, pp. 16 and 20.     (P. Gi.)
+
+
+
+
+EA (written by means of two signs signifying "house" and "water"), in
+the Babylonian religion, originally the patron deity of Eridu, situated
+in ancient times at the head of the Persian Gulf, but now, by reason of
+the constant accumulation of soil in the Euphrates valley, at some
+distance from the gulf. Eridu, meaning "the good city," was one of the
+oldest settlements in the Euphrates valley, and is now represented by
+the mounds known as Abu Shahrein. In the absence of excavations on that
+site, we are dependent for our knowledge of Ea on material found
+elsewhere. This is, however, sufficient to enable us to state definitely
+that Ea was a water-deity, and there is every reason to believe that the
+Persian Gulf was the body of water more particularly sacred to him.
+Whether Ea (or A-e as some scholars prefer) represents the real
+pronunciation of his name we do not know. All attempts to connect Ea
+with Yah and Yahweh are idle conjectures without any substantial basis.
+He is figured as a man covered with the body of a fish, and this
+representation, as likewise the name of his temple E-apsu, "house of
+the watery deep," points decidedly to his character as a god of the
+waters (see OANNES). Of his cult at Eridu, which reverts to the oldest
+period of Babylonian history, nothing definite is known beyond the fact
+that the name of his temple was E-saggila, "the lofty house"--pointing
+to a staged tower as in the case of the temple of Bel (q.v.) at Nippur,
+known as E-Kur, i.e. "mountain house"--and that incantations, involving
+ceremonial rites, in which water as a sacred element played a prominent
+part, formed a feature of his worship. Whether Eridu at one time also
+played an important political rôle is not certain, though not
+improbable. At all events, the prominence of the Ea cult led, as in the
+case of Nippur, to the survival of Eridu as a sacred city, long after it
+had ceased to have any significance as a political centre. Myths in
+which Ea figures prominently have been found in Assur-bani-pal's
+library, indicating that Ea was regarded as the protector and teacher of
+mankind. He is essentially a god of civilization, and it was natural
+that he was also looked upon as the creator of man, and of the world in
+general. Traces of this view appear in the Marduk epic celebrating the
+achievements of this god, and the close connexion between the Ea cult at
+Eridu and that of Marduk also follows from two considerations: (1) that
+the name of Marduk's sanctuary at Babylon bears the same name,
+E-saggila, as that of Ea in Eridu, and (2) that Marduk is generally
+termed the son of Ea, who derives his powers from the voluntary
+abdication of the father in favour of his son. Accordingly, the
+incantations originally composed for the Ea cult were re-edited by the
+priests of Babylon and adapted to the worship of Marduk, and, similarly,
+the hymns to Marduk betray traces of the transfer of attributes to
+Marduk which originally belonged to Ea.
+
+It is, however, more particularly as the third figure in the triad, the
+two other members of which were Anu (q.v.) and Bel (q.v.), that Ea
+acquires his permanent place in the pantheon. To him was assigned the
+control of the watery element, and in this capacity he becomes the _shar
+apsi_, i.e. king of the Apsu or "the deep." The Apsu was figured as an
+ocean encircling the earth, and since the gathering place of the dead,
+known as Aralu, was situated near the confines of the Apsu, he was also
+designated as En-Ki, i.e. "lord of that which is below," in contrast to
+Anu, who was the lord of the "above" or the heavens. The cult of Ea
+extended throughout Babylonia and Assyria. We find temples and shrines
+erected in his honour, e.g. at Nippur, Girsu, Ur, Babylon, Sippar and
+Nineveh, and the numerous epithets given to him, as well as the various
+forms under which the god appears, alike bear witness to the popularity
+which he enjoyed from the earliest to the latest period of
+Babylonian-Assyrian history. The consort of Ea, known as Damkina, "lady
+of that which is below," or Nin-Ki, having the same meaning, or
+Damgal-nunna, "great lady of the waters," represents a pale reflection
+of Ea and plays a part merely in association with her lord.     (M. Ja.)
+
+
+
+
+EABANI, the name of the friend of Gilgamesh, the hero in the Babylonian
+epic (see GILGAMESH, EPIC OF). Eabani, whose name signifies "Ea
+creates," pointing to the tradition which made the god Ea (q.v.) the
+creator of mankind, is represented in the epic as the type of the
+primeval man. He is a wild man who lives with the animals of the field
+until lured away from his surroundings by the charms of a woman. Created
+to become a rival to Gilgamesh, he strikes up a friendship with the
+hero, and together they proceed to a cedar forest guarded by Khumbaba,
+whom they kill. The goddess Irnina (a form of Ishtar, q.v.) in revenge
+kills Eabani, and the balance of the epic is taken up with Gilgamesh's
+lament for his friend, his wanderings in quest of a remote ancestor,
+Ut-Napishtim, from whom he hopes to learn how he may escape the fate of
+Eabani, and his finally learning from his friend of the sad fate in
+store for all mortals except the favourites of the god, like
+Ut-Napishtim, to whom immortal life is vouchsafed as a special boon.
+     (M. Ja.)
+
+
+
+
+EACHARD, JOHN (1636?-1697), English divine, was born in Suffolk, and was
+educated at Catharine Hall, Cambridge, of which he became master in 1675
+in succession to John Lightfoot. He was created D.D. in 1676 by royal
+mandate, and was twice (in 1679 and 1695) vice-chancellor of the
+university. He died on the 7th of July 1697. In 1670 he had published
+anonymously a humorous satire entitled _The Ground and Occasions of the
+Contempt of the Clergy enquired into in a letter to R. L._, which
+excited much attention and provoked several replies, one of them being
+from John Owen. These were met by _Some Observations, &c., in a second
+letter to R. L._ (1671), written in the same bantering tone as the
+original work. Eachard attributed the contempt into which the clergy had
+fallen to their imperfect education, their insufficient incomes, and the
+want of a true vocation. His descriptions, which were somewhat
+exaggerated, were largely used by Macaulay in his _History of England_.
+He gave amusing illustrations of the absurdity and poverty of the
+current pulpit oratory of his day, some of them being taken from the
+sermons of his own father. He attacked the philosophy of Hobbes in his
+_Mr Hobb's State of Nature considered; in a dialogue between Philautus
+and Timothy_ (1672), and in his _Some Opinions of Mr Hobbs considered in
+a second dialogue_ (1673). These were written in their author's chosen
+vein of light satire, and Dryden praised them as highly effective within
+their own range. Eachard's own sermons, however, were not superior to
+those he satirized. Swift (_Works_, xii. 279) alludes to him as a signal
+instance of a successful humorist who entirely failed as a serious
+writer.
+
+  A collected edition of his works in three volumes, with a notice of
+  his life, was published in 1774. The _Contempt of the Clergy_ was
+  reprinted in E. Arber's _English Garner_. _A Free Enquiry into the
+  Causes of the very great Esteem that the Nonconforming Preachers are
+  generally in with their Followers_ (1673) has been attributed to
+  Eachard on insufficient grounds.
+
+
+
+
+EADBALD (d. 640), king of Kent, succeeded to the throne on the death of
+his father Æthelberht in 616. He had not been influenced by the teaching
+of the Christian missionaries, and his first step on his accession was
+to marry his father's widow. After his subsequent conversion by
+Laurentius, archbishop of Canterbury, he recalled the bishops Mellitus
+and Justus, and built a church dedicated to the Virgin at Canterbury. He
+arranged a marriage between his sister Æthelberg and Edwin of
+Northumbria, on whose defeat and death in 633 he received his sister and
+Paulinus, and offered the latter the bishopric of Rochester. Eadbald
+married Emma, a Frankish princess, and died on the 20th of January 640.
+
+  See Bede, _Historia ecclesiastica_ (ed. C. Plummer, Oxford, 1896);
+  _Saxon Chronicle_ (ed. J. Earle and C. Plummer, Oxford, 1899).
+
+
+
+
+EADIE, JOHN (1810-1876), Scottish theologian and biblical critic, was
+born at Alva, in Stirlingshire, on the 9th of May 1810. Having taken the
+arts curriculum at Glasgow University, he studied for the ministry at
+the Divinity Hall of the Secession Church, a dissenting body which, on
+its union a few years later with the Relief Church, adopted the title
+United Presbyterian. In 1835 he became minister of the Cambridge Street
+Secession church in Glasgow, and for many years he was generally
+regarded as the leading representative of his denomination in Glasgow.
+As a preacher, though he was not eloquent, he was distinguished by good
+sense, earnestness and breadth of sympathy. In 1863 he removed with a
+portion of his congregation to a new church at Lansdowne Crescent. In
+1843 Eadie was appointed professor of biblical literature and
+hermeneutics in the Divinity Hall of the United Presbyterian body. He
+held this appointment along with his ministerial charge till the close
+of his life. Though not a profound scholar, he was surpassed by few
+biblical commentators of his day in range of learning, and in soundness
+of judgment. In the professor's chair, as in the pulpit, his strength
+lay in the tact with which he selected the soundest results of biblical
+criticism, whether his own or that of others, and presented them in a
+clear and connected form, with a constant view to their practical
+bearing. He received the degree of LL.D. from Glasgow in 1844, and that
+of D.D. from St Andrews in 1850.
+
+His publications were connected with biblical criticism and
+interpretation, some of them being for popular use and others more
+strictly scientific. To the former class belong the _Biblical
+Cyclopaedia_, his edition of _Cruden's Concordance_, his _Early Oriental
+History_, and his discourses on the _Divine Love_ and on _Paul the
+Preacher_; to the latter his commentaries on the Greek text of St Paul's
+epistles to the Ephesians, Colossians, Philippians and Galatians,
+published at intervals in four volumes. His last work was the _History
+of the English Bible_ (2 vols., 1876). He rendered good service as one
+of the revisers of the authorized version. He died at Glasgow on the 3rd
+of June 1876. His valuable library was bought and presented to the
+United Presbyterian College.
+
+
+
+
+EADMER, or EDMER (c. 1060-c. 1124), English historian and ecclesiastic,
+was probably, as his name suggests, of English, and not of Norman
+parentage. He became a monk in the Benedictine monastery of Christ
+Church, Canterbury, where he made the acquaintance of Anselm, at that
+time visiting England as abbot of Bec. The intimacy was renewed when
+Anselm became archbishop of Canterbury in 1093; thenceforward Eadmer was
+not only his disciple and follower, but his friend and director, being
+formally appointed to this position by Pope Urban II. In 1120 he was
+nominated to the archbishopric of St Andrews, but as the Scots would not
+recognize the authority of the see of Canterbury he was never
+consecrated, and soon afterwards he resigned his claim to the
+archbishopric. His death is generally assigned to the year 1124.
+
+Eadmer left a large number of writings, the most important of which is
+his _Historiae novorum_, a work which deals mainly with the history of
+England between 1066 and 1122. Although concerned principally with
+ecclesiastical affairs scholars agree in regarding the _Historiae_ as
+one of the ablest and most valuable writings of its kind. It was first
+edited by John Selden in 1623 and, with Eadmer's _Vita Anselmi_, has
+been edited by Martin Rule for the "Rolls Series" (London, 1884). The
+_Vita Anselmi_, first printed at Antwerp in 1551, is probably the best
+life of the saint. Less noteworthy are Eadmer's lives of St Dunstan, St
+Bregwin, archbishop of Canterbury, and St Oswald, archbishop of York;
+these are all printed in Henry Wharton's _Anglia Sacra_, part ii.
+(1691), where a list of Eadmer's writings will be found. The manuscripts
+of most of Eadmer's works are preserved in the library of Corpus Christi
+College, Cambridge.
+
+  See M. Rule, _On Eadmer's Elaboration of the first four Books of
+  "Historiae novorum"_ (1886); and Père Ragey, _Eadmer_ (Paris, 1892).
+
+
+
+
+EADS, JAMES BUCHANAN (1820-1887), American engineer, was born at
+Lawrenceburg, Indiana, on the 23rd of May 1820. His first engineering
+work of any importance was in raising sunken steamers. In 1845 he
+established glass works in St Louis. During the Civil War he constructed
+ironclad steamers and mortar boats for the Federal government. His next
+important engineering achievement was the construction of the great
+steel arch bridge across the Mississippi at St Louis (see BRIDGE, fig.
+29), upon which he was engaged from 1867 till 1874. The work, however,
+upon which his reputation principally rests was his deepening and fixing
+the channel at the mouths of the Mississippi by means of jetties,
+whereby the narrowed stream was made to scour out its own channel and
+carry the sediment out to sea. Shortly before his death he projected a
+scheme for a ship railway across the Isthmus of Tehuantepec, in lieu of
+an isthmian canal. He died at Nassau, in the Bahamas, on the 8th of
+March 1887.
+
+
+
+
+EAGLE (Fr. _aigle_, from the Lat. _aquila_), the name generally given to
+the larger diurnal birds of prey which are not vultures; but the limits
+of the subfamily _Aquilinae_ have been very variously assigned by
+different writers on systematic ornithology, and there are eagles
+smaller than certain buzzards. By some authorities the _Laemmergeier_ of
+the Alps, and other high mountains of Europe, North Africa and Asia, is
+accounted an eagle, but by others the genus _Gypaetus_ is placed with
+the _Vulturidae_ as its common English name (bearded vulture)
+shows. There are also other forms, such as the South American _Harpyia_
+and its allies, which though generally called eagles have been ranked as
+buzzards. In the absence of any truly scientific definition of the
+family _Aquilinae_ it is best to leave these and many other more or less
+questionable members of the group--such as the genera _Spizaetus_,
+_Circaetus_, _Spilornis_, _Helotarsus_, and so forth--and to treat here
+of those whose position cannot be gainsaid.
+
+[Illustration: FIG. 1.--Sea-Eagle.]
+
+True eagles inhabit all the regions of the world, and some seven or
+eight species at least are found in Europe, of which two are resident in
+the British Islands. In England and in the Lowlands of Scotland eagles
+only exist as stragglers; but in the Hebrides and some parts of the
+Highlands a good many may yet be found, and their numbers appear to have
+rather increased of late years than diminished; for the foresters and
+shepherds, finding that a high price can be got for their eggs, take
+care to protect the owners of the eyries, which are nearly all well
+known, and to keep up the stock by allowing them at times to rear their
+young. There are also now not a few occupiers of Scottish forests who
+interfere so far as they can to protect the king of birds.[1] In Ireland
+the extirpation of eagles seems to have been carried on almost
+unaffected by the prudent considerations which in the northern kingdom
+have operated so favourably for the race, and except in the wildest
+parts of Donegal, Mayo and Kerry, eagles in the sister island are almost
+birds of the past.
+
+Of the two British species the erne (Icel. _Oern_) or sea-eagle (by some
+called also the white-tailed and cinereous eagle)--_Haliaetus
+albicilla_--affects chiefly the coast and neighbourhood of inland
+waters, living in great part on the fish and refuse that is thrown up on
+the shore, though it not unfrequently takes living prey, such as lambs,
+hares and rabbits. On these last, indeed, young examples mostly feed
+when they wander southward in autumn, as they yearly do, and appear in
+England. The adults (fig. 1) are distinguished by their prevalent
+greyish-brown colour, their pale head, yellow beak and white
+tail--characters, however, wanting in the immature, which do not assume
+the perfect plumage for some three or four years. The eyry is commonly
+placed in a high cliff or on an island in a lake--sometimes on the
+ground, at others in a tree--and consists of a vast mass of sticks in
+the midst of which is formed a hollow lined with _Luzula sylvatica_ (as
+first observed by John Wolley) or some similar grass, and here are laid
+the two or three white eggs. In former days the sea-eagle seems to have
+bred in several parts of England--as the Lake district, and possibly
+even in the Isle of Wight and on Dartmoor. This species inhabits all the
+northern part of the Old World from Iceland to Kamchatka, and breeds in
+Europe so far to the southward as Albania. In the New World, however, it
+is only found in Greenland, being elsewhere replaced by the white-headed
+or bald eagle, _H. leucocephalus_, a bird of similar habits, and the
+chosen emblem of the United States of America. In the far east of Asia
+occurs a still larger and finer sea-eagle, _H. pelagicus_, remarkable
+for its white thighs and upper wing-coverts. South-eastern Europe and
+India furnish a much smaller species, _H. leucoryphus_, which has its
+representative, _H. leucogaster_, in the Malay Archipelago and
+Australia, and, as allies in South Africa and Madagascar, _H. vocifer_
+and _H. vociferoides_ respectively. All these eagles may be
+distinguished by their scaly tarsi, while the group next to be treated
+of have the tarsi feathered to the toes.
+
+[Illustration: FIG. 2.--Mountain-Eagle.]
+
+The golden or mountain eagle, _Aquila chrysaetus_, is the second British
+species. This also formerly inhabited England, and a nest, found in 1668
+in the Peak of Derbyshire, is well described by Willughby, in whose time
+it was said to breed also in the Snowdon range. It seldom if ever
+frequents the coast, and is more active on the wing than the sea-eagle,
+being able to take some birds as they fly, but a large part of its
+sustenance is the flesh of animals that die a natural death. Its eyry is
+generally placed and built like that of the other British species,[2]
+but the neighbourhood of water is not requisite. The eggs, from two to
+four in number, vary from a pure white to a mottled, and often highly
+coloured, surface, on which appear different shades of red and purple.
+The adult bird (fig. 2) is of a rich dark brown, with the elongated
+feathers of the neck, especially on the nape, light tawny, in which
+imagination sees a "golden" hue, and the tail marbled with brown and
+ashy-grey. In the young the tail is white at the base, and the neck has
+scarcely any tawny tint. The golden eagle does not occur in Iceland, but
+occupies suitable situations over the rest of the Palaearctic Region and
+a considerable portion of the Nearctic--though the American bird has
+been, by some, considered a distinct species. Domesticated, it has many
+times been trained to take prey for its master in Europe, and to this
+species is thought to belong an eagle habitually used by the Kirghiz
+Tatars, who call it _Bergut_ or _Bearcoot_, for the capture of
+antelopes, foxes and wolves. It is carried hooded on horseback or on a
+perch between two men, and released when the quarry is in sight. Such a
+bird, when well trained, is valued, says P.S. Pallas, at the price of
+two camels. It is quite possible, however, that more than one kind of
+eagle is thus used, and the services of _A. heliaca_ (which is the
+imperial eagle of some writers[3]) and of _A. mogilnik_--both of which
+are found in central Asia, as well as in south-eastern Europe--may also
+be employed.
+
+A smaller form of eagle, which has usually gone under the name of _A.
+naevia_, is now thought by the best authorities to include three local
+races, or, in the eyes of some, species. They inhabit Europe, North
+Africa and western Asia to India, and two examples of one of them--_A.
+clanga_, the form which is somewhat plentiful in north-eastern
+Germany--have occurred in Cornwall. The smallest true eagle is _A.
+pennata_, which inhabits southern Europe, Africa and India. Differing
+from other eagles of their genus by its wedge-shaped tail, though
+otherwise greatly resembling them, is the _A. audax_ of Australia.
+Lastly may be noticed here a small group of eagles, characterized by
+their long legs, forming the genus _Nisaetus_, of which one species, _N.
+fasciatus_, is found in Europe.      (A. N.)
+
+
+FOOTNOTES:
+
+  [1] Lord Breadalbane (d. 1871) was perhaps the first large landowner
+    who set the example that has been since followed by others. On his
+    unrivalled forest of Black Mount, eagles--elsewhere persecuted to the
+    death--were by him ordered to be unmolested so long as they were not
+    numerous enough to cause considerable depredations on the farmers'
+    flocks. He thought that the spectacle of a soaring eagle was a
+    fitting adjunct to the grandeur of his Argyllshire mountain scenery,
+    and a good equivalent for the occasional loss of a lamb, or the
+    slight deduction from the rent paid by his tenantry in consequence.
+
+  [2] As already stated, the site chosen varies greatly. Occasionally
+    placed in a niche in what passes for a perpendicular cliff to which
+    access could only be gained by a skilful cragsman with a rope, the
+    writer has known a nest to within 10 or 15 yds. of which he rode on a
+    pony. Two beautiful views of as many golden eagles' nests, drawn on
+    the spot by Joseph Wolf, are given in the _Ootheca Wolleyana_, and a
+    fine series of eggs is also figured in the same work.
+
+  [3] Which species may have been the traditional emblem of Roman
+    power, and the _Ales Jovis_, is very uncertain.
+
+
+
+
+EAGLEHAWK, a borough of Bendigo county, Victoria, Australia, 105 m. by
+rail N.N.W. of Melbourne and 4 m. from Bendigo, with which it is
+connected by steam tramway. Pop. (1901) 8130. It stands on the Bendigo
+gold-bearing reef, and its mines are important.
+
+
+
+
+EAGRE (a word of obscure origin; the earliest form seems to be _higre_,
+Latinized as _higra_, which William of Malmesbury gives as the name of
+the bore in the Severn; the _New English Dictionary_ rejects the usual
+derivations from the O. Eng. _eagor_ or _egor_, which is seen in
+compounds meaning "flood," and also the connexion with the Norse sea-god
+_Aegir_), a tide wave of great height rushing up an estuary (see BORE),
+used locally of the Humber and Trent.
+
+
+
+
+EAKINS, THOMAS (1844-   ), American portrait and figure painter, was
+born at Philadelphia, on the 25th of July 1844. A pupil of J.L. Gérôme,
+in the École des Beaux-Arts, Paris, and Also of Léon Bonnat, besides
+working in the studio of the sculptor Dumont, he became a prolific
+portrait painter. He also painted genre pictures, sending to the
+Centennial Exhibition at Philadelphia, in 1876, the "Chess Players," now
+in the Metropolitan Museum of Art, New York. A large canvas, "The
+Surgical Clinic of Professor Gross," owned by Jefferson Medical College,
+Philadelphia, contains many life-sized figures. Eakins, with his pupil
+Samuel Murray (b. 1870), modelled the heroic "Prophets" for the
+Witherspoon Building, Philadelphia, and his work in painting has a
+decided sculptural quality. He was for some years professor of anatomy
+at the schools of the Pennsylvania Academy of Fine Arts in Philadelphia.
+A man of great inventiveness, he experimented in many directions,
+depicting on canvas modern athletic sports, the negro, and early
+American life, but he is best known by his portraits. He received awards
+at the Columbian (1893), Paris (1900), Pan-American (1900), and the St
+Louis (1904), Expositions; and won the Temple medal in the Pennsylvania
+Academy of Fine Arts, and the Proctor prize of the National Academy of
+Design.
+
+
+
+
+EALING, a municipal borough in the Ealing parliamentary division of
+Middlesex, England, suburban to London, 9 m. W. of St Paul's cathedral.
+Pop. (1891) 23,979; (1901) 33,031. The nucleus of the town, the ancient
+village, lies south of the highroad to Uxbridge, west of the open Ealing
+Common. The place is wholly residential. At St Mary's church, almost
+wholly rebuilt c. 1870, are buried John Oldmixon, the historian (d.
+1742), and Horne Tooke (d. 1812). The church of All Saints (1905)
+commemorates Spencer Perceval, prime minister, who was assassinated in
+the House of Commons in 1812. It was erected under the will of his
+daughter Frederica, a resident of Ealing. Gunnersbury Park, south of
+Ealing Common, is a handsome Italian mansion. Among former owners of the
+property was Princess Amelia, daughter of George II., who lived here
+from 1761 till her death in 1786. The name of Gunnersbury is said to be
+traceable to the residence here of Gunilda, niece of King Canute. The
+manor of Ealing early belonged to the see of London, but it is not
+mentioned in Domesday and its history is obscure.
+
+
+
+
+EAR (common Teut.; O.E. _éare_, Ger. _Ohr_, Du. _oor_, akin to Lat.
+_auris_, Gr. [Greek: ous]), in anatomy, the organ of hearing. The human
+ear is divided into three parts--external, middle and internal. The
+external ear consists of the pinna and the external auditory meatus. The
+pinna is composed of a yellow fibro-cartilaginous framework covered by
+skin, and has an external and an internal or cranial surface. Round the
+margin of the external surface in its upper three quarters is a rim
+called the helix (fig. 1, a), in which is often seen a little prominence
+known as Darwin's tubercle, representing the folded-over apex of a
+prick-eared ancestor. Concentric with the helix and nearer the meatus is
+the antihelix (c), which, above, divides into two limbs to enclose the
+triangular fossa of the antihelix. Between the helix and the antihelix
+is the fossa of the helix. In front of the antihelix is the deep fossa
+known as the concha (fig. 1, d), and from the anterior part of this the
+meatus passes inward into the skull. Overlapping the meatus from in
+front is a flap called the tragus, and below and behind this is another
+smaller flap, the antitragus. The lower part of the pinna is the lobule
+(e), which contains no cartilage. On the cranial surface of the pinna
+elevations correspond to the concha and to the fossae of the helix and
+antihelix. The pinna can be slightly moved by the anterior, superior and
+posterior auricular muscles, and in addition to these there are four
+small intrinsic muscles on the external surface, known as the helicis
+major and minor, the tragicus and the antitragicus, and two on the
+internal surface called the obliquus and transversus. The external
+auditory meatus (fig. 1, n) is a tube running at first forward and
+upward, then a little backward and then forward and slightly downward;
+of course all the time it is also running inward until the tympanic
+membrane is reached. The tube is about an inch long, its outer third
+being cartilaginous and its inner two-thirds bony. It is lined by skin
+in its whole length, the sweat glands of which are modified to secrete
+the wax or cerumen.
+
+[Illustration: FIG. 1.--The Ear as seen in Section.
+
+  a, Helix.                     m, Tip of petrous process.
+  b, Antitragus.                n, External auditory meatus.
+  c, Antihelix.                 o, Membrana tympani.
+  d, Concha.                    p, Tympanum.
+  e, Lobule.                    1, points to malleus.
+  f, Mastoid process.           2, to incus.
+  g, Portio dura.               3, to stapes.
+  h, Styloid process.           4, to cochlea.
+  k, Internal carotid artery.   5, 6, 7, the three semicircular canals.
+  l, Eustachian tube.           8 and 9, facial and auditory nerves.]
+
+The middle ear or tympanum (fig. 1, p) is a small cavity in the temporal
+bone, the shape of which may perhaps be realized by imagining a hock
+bottle subjected to lateral pressure in such a way that its circular
+section becomes triangular, the base of the triangle being above. The
+neck of the bottle, also laterally compressed, will represent the
+Eustachian tube (fig. 1, l), which runs forward, inward and downward, to
+open into the naso-pharynx, and so admits air into the tympanum. The
+bottom of the bottle will represent the posterior wall of the tympanum,
+from the upper part of which an opening leads backward into the mastoid
+antrum and so into the air-cells of the mastoid process. Lower down is a
+little pyramid which transmits the stapedius muscle, and at the base of
+this is a small opening known as the iter chordae posterius, for the
+chorda tympani to come through from the facial nerve. The roof is formed
+by a very thin plate of bone, called the tegmen tympani, which separates
+the cavity from the middle fossa of the skull. Below the roof the upper
+part of the tympanum is somewhat constricted off from the rest, and to
+this part the term "attic" is often applied. The floor is a mere groove
+formed by the meeting of the external and internal walls. The outer wall
+is largely occupied by the tympanic membrane (fig. 1, o), which entirely
+separates the middle ear from the external auditory meatus; it is
+circular, and so placed that it slopes from above, downward and inward,
+and from behind, forward and inward. Externally it is lined by skin,
+internally by mucous membrane, while between the two is a firm fibrous
+membrane, convex inward about its centre to form the umbo. Just in front
+of the membrane on the outer wall is the Glaserian fissure leading to
+the glenoid cavity, and close to this is the canal of Huguier for the
+chorda tympani nerve. The inner wall shows a promontory caused by the
+cochlea and grooved by the tympanic plexus of nerves; above and behind
+it is the fenestra ovalis, while below and behind the fenestra rotunda
+is seen, closed by a membrane. Curving round, above and behind the
+promontory and fenestrae, is a ridge caused by the aqueductus Fallopii
+or canal for the facial nerve. The whole tympanum is about half an inch
+from before backward, and half an inch high, and is spanned from side to
+side by three small bones, of which the malleus (fig. 1, 1) is the most
+external. This is attached by its handle to the umbo of the tympanic
+membrane, while its head lies in the attic and articulates posteriorly
+with the upper part of the next bone or incus (fig. 1, 2). The long
+process of the incus runs downward and ends in a little knob called the
+os orbiculare, which is jointed on to the stapes or stirrup bone (fig.
+1, 3). The two branches of the stapes are anterior and posterior, while
+the footplate fits into the fenestra ovalis and is bound to it by a
+membrane. It will thus be seen that the stapes lies nearly at right
+angles to the long process of the incus. From the front of the malleus a
+slender process projects forward into the Glaserian fissure, while from
+the back of the incus the posterior process is directed backward and is
+attached to the posterior wall of the tympanum. These two processes form
+a fulcrum by which the lever action of the malleus and incus is brought
+about, so that when the handle of the malleus is pushed in by the
+membrane the head moves out; the top of the incus, attached to it, also
+moves out, and the os orbiculare moves in, and so the stapes is pressed
+into the fenestra ovalis. The stapedius and tensor tympanic muscles, the
+latter of which enters the tympanum in a canal just above the
+Eustachian tube to be attached to the malleus, modify the movements of
+the ossicles.
+
+The mucous membrane lining the tympanum is continuous through the
+Eustachian tube with that of the naso-pharynx, and is reflected on to
+the ossicles, muscles and chorda tympani nerve. It is ciliated except
+where it covers the membrana tympani, ossicles and promontory; here it
+is stratified.
+
+[Illustration: FIG. 2.--Diagram of the Membranous Labyrinth.
+
+  DC, Ductus cochlearis.
+  dr, Ductus reuniens.
+  S, Sacculus.
+  U, Utriculus.
+  dv, Ductus endolymphaticus.
+  SC, Semicircular canals.
+         (After Waldeyer.)]
+
+The internal ear or labyrinth consists of a bony and a membranous part,
+the latter of which is contained in the former. The bony labyrinth is
+composed of the vestibule, the semicircular canals and the cochlea. The
+vestibule lies just internal to the posterior part of the tympanum, and
+there would be a communication between the two, through the fenestra
+ovalis, were it not that the footplate of the stapes blocks the way. The
+inner wall of the vestibule is separated from the bottom of the internal
+auditory meatus by a plate of bone pierced by many foramina for branches
+of the auditory nerve (fig. 1, 9), while at the lower part is the
+opening of the aqueductus vestibuli, by means of which a communication
+is established with the posterior cranial fossa. Posteriorly the three
+semicircular canals open into the vestibule; of these the external (fig.
+1, 7) has two independent openings, but the superior and posterior (fig.
+1, 5 and 6) join together at one end and so have a common opening, while
+at their other ends they open separately. The three canals have
+therefore five openings into the vestibule instead of six. One end of
+each canal is dilated to form its ampulla. The superior semicircular
+canal is vertical, and the two pillars of its arch are nearly external
+and internal; the external canal is horizontal, its two pillars being
+anterior and posterior, while the convexity of the arch of the posterior
+canal is backward and its two pillars are superior and inferior.
+Anteriorly the vestibule leads into the cochlea (fig. 1, 4), which is
+twisted two and a half times round a central pillar called the modiolus,
+the whole cochlea forming a rounded cone something like the shell of a
+snail though it is only about 5 mm. from base to apex. Projecting from
+the modiolus is a horizontal plate which runs round it from base to apex
+like a spiral staircase; this is known as the lamina spiralis, and it
+stretches nearly half-way across the canal of the cochlea. At the summit
+it ends in a little hook named the hamulus. The modiolus is pierced by
+canals which transmit branches of the auditory nerve to the lamina
+spiralis.
+
+[Illustration: FIG. 3.--cl, Columnar cells covering the crista acustica;
+p, peripheral, and c, central processes of auditory cells; n, nerve
+fibres. (After Rüdinger.)]
+
+The membranous labyrinth lies in the bony labyrinth, but does not fill
+it; between the two is the fluid called perilymph, while inside the
+membranous labyrinth is the endolymph. In the bony vestibule lie two
+membranous bags, the saccule (fig. 2, S) in front, and the utricle (fig.
+2, U) behind; each of these has a special patch or macula to which twigs
+of the auditory nerve are supplied, and in the mucous membrane of which
+specialized hair cells are found (fig. 3, p).
+
+Attached to the maculae are crystals of carbonate of lime called
+otoconia. The membranous semicircular canals are very much smaller in
+section than the bony; in the ampulla of each is a ridge, the crista
+acustica, which is covered by a mucous membrane containing sensory hair
+cells like those in the maculae. All the canals open into the utricle.
+From the lower part of the saccule a small canal called the ductus
+endolymphaticus (fig. 2, dv) runs into the aqueductus vestibuli; it is
+soon joined by a small duct from the utricle, and ends, close to the
+dura mater of the posterior fossa of the cranium, as the saccus
+endolymphaticus, which may have minute perforations through which the
+endolymph can pass. Anteriorly the saccule communicates with the
+membranous cochlea or scala media by a short ductus reuniens (fig. 2,
+dr). A section through each turn of the cochlea shows the bony lamina
+spiralis, already noticed, which is continued right across the canal by
+the basilar membrane (fig. 4, bm), thus cutting the canal into an upper
+and lower half and connected with the outer wall by the strong spiral
+ligament (fig. 4, sl). Near the free end of the lamina spiralis another
+membrane called the membrane of Reissner (fig. 4, mR) is attached, and
+runs outward and upward to the outer wall, taking a triangular slice out
+of the upper half of the section. There are now three canals seen in
+section, the upper of which is the scala vestibuli (fig. 4, SV), the
+middle and outer the scala media, ductus cochlearis or true membranous
+cochlea (fig. 4, DC), while the lower is the scala tympani (fig. 4, ST).
+The scala vestibuli and scala tympani communicate at the apex of the
+cochlea by an opening known as the helicotrema, so that the perilymph
+can here pass from one canal to the other. At the base of the cochlea
+the perilymph in the scala vestibuli is continuous with that in the
+vestibule, but that in the scala tympani bathes the inner surface of the
+membrane stretched across the fenestra rotunda, and also communicates
+with the subarachnoid space through the aqueductus cochleae, which opens
+into the posterior cranial fossa. The scala media containing endolymph
+communicates, as has been shown, with the saccule through the canalis
+reuniens, while, at the apex of the cochlea, it ends in a blind
+extremity of considerable morphological interest called the lagena.
+
+[Illustration: FIG. 4.--Transverse Section through the Tube of the
+Cochlea.
+
+  m, Modiolus.                 bm, Basilar membrane.
+  0, Outer wall of cochlea.    cs, Crista spiralis.
+  SV, Scala vestibuli.         sl, Spiral ligament.
+  ST, Scala tympani.           sg, Spiral ganglion of auditory nerve.
+  DC, Ductus cochlearis.       oc, Organ of Corti.
+  mR, Membrane of Reissner.]
+
+The scala media contains the essential organ of hearing or organ of
+Corti (fig. 4, oc), which lies upon the inner part of the basilar
+membrane; it consists of a tunnel bounded on each side of the inner and
+outer rods of Corti; on each side of these are the inner and outer hair
+cells, between the latter of which are found the supporting cells of
+Deiters. Most externally are the large cells of Hensen. A delicate
+membrane called the lamina reticularis covers the top of all these, and
+is pierced by the hairs of the hair cells, while above this is the loose
+membrana tectoria attached to the periosteum of the lamina spiralis,
+near its tip, internally, and possibly to some of Deiter's cells
+externally. The cochlear branch of the auditory nerve enters the lamina
+spiralis, where a spiral ganglion (fig. 4, sg) is developed on it; after
+this it is distributed to the inner and outer hair cells.
+
+[Illustration: FIG. 5.--Transverse Section of Corti's Organ from the
+Central Coil of Cochlea (Retzius).
+
+(From R. Howden--Cunningham's _Text-Book of Anatomy_.)]
+
+  For further details see _Text-Book of Anatomy_, edited by D.J.
+  Cunningham (Edinburgh, 1906); Quain's _Elements of Anatomy_ (London,
+  1893); Gray's _Anatomy_ (London, 1905); _A Treatise on Anatomy_,
+  edited by H. Morris (London, 1902); _A Text-Book of Human Anatomy_, by
+  A. Macalister (London, 1889).
+
+_Embryology._--The pinna is formed from six tubercles which appear round
+the dorsal end of the hyomandibular cleft or, more strictly speaking,
+pouch. Those for the tragus and anterior part of the helix belong to the
+first or mandibular arch, while those for the antitragus, antihelix and
+lobule come from the second or hyoid arch. The tubercle for the helix is
+dorsal to the end of the cleft where the two arches join. The external
+auditory meatus, tympanum and Eustachian tube are remains of the
+hyomandibular cleft, the membrana tympani being a remnant of the cleft
+membrane and therefore lined by ectoderm outside and entoderm inside.
+The origin of the ossicles is very doubtful. H. Gadow's view, which is
+one of the latest, is that all three are derived from the hyomandibular
+plate which connects the dorsal ends of the hyoid and mandibular bars
+(_Anatomischer Anzeiger_, Bd. xix., 1901, p. 396). Other papers which
+should be consulted are those of E. Gaupp, _Anatom. Hefte, Ergebnisse_,
+Bd. 8, 1898, p. 991, and J.A. Hammar, _Archiv f. mikr. Anat._ lix.,
+1902. These papers will give a clue to the immense literature of the
+subject. The internal ear first appears as a pit from the cephalic
+ectoderm, the mouth of which in Man and other mammals closes up, so that
+a pear-shaped cavity is left. The stalk of the pear which is nearest the
+point of invagination is called the recessus labyrinthi, and this, after
+losing its connexion with the surface of the embryo, grows backward
+toward the posterior cranial fossa and becomes the ductus
+endolymphaticus. The lower part of the vesicle grows forward and becomes
+the cochlea, while from the upper part three hollow circular plates grow
+out, the central parts of which disappear, leaving the margin as the
+semicircular canals. Subsequently constrictions appear in the vesicle
+marking off the saccule and utricle. From the surrounding mesoderm the
+petrous bone is formed by a process of chondrification and ossification.
+
+  See W. His, Junr., _Archiv f. Anat. und Phys._, 1889, supplement, p.
+  1; also Streeter, _Am. Journ. of Anat._ vi., 1907.
+
+_Comparative Anatomy._--The ectodermal inpushing of the internal ear has
+probably a common origin with the organs of the lateral line of fish. In
+the lower forms the ductus endolymphaticus retains its communication
+with the exterior on the dorsum of the head, and in some Elasmobranchs
+the opening is wide enough to allow the passage of particles of sand
+into the saccule. It is probable that this duct is the same which,
+taking a different direction and losing its communication with the skin,
+abuts on the posterior cranial fossa of higher forms (see Rudolf Krause,
+"Die Entwickelung des Aq. vestibuli seu d. Endelymphaticus," _Anat.
+Anzeiger_, Bd. xix., 1901, p. 49). In certain Teleostean fishes the swim
+bladder forms a secondary communication with the internal ear by means
+of special ossicles (see G. Ridewood, _Journ. Anat. & Phys._ vol.
+xxvi.). Among the Cyclostomata the external semicircular canals are
+wanting; Petromyzon has the superior and posterior only, while in Myxine
+these two appear to be fused so that only one is seen. In higher types
+the three canals are constant. Concretions of carbonate of lime are
+present in the internal ears of almost all vertebrates; when these are
+very small they are called otoconia, but when, as in most of the
+teleostean fishes, they form huge concretions, they are spoken of as
+otoliths. One shark, Squatina, has sand instead of otoconia (C. Stewart,
+_Journ. Linn. Society_, xxix. 409). The utricle, saccule, semicircular
+canals, ductus endolymphaticus and a short lagena are the only parts of
+the ear present in fish.
+
+The Amphibia have an important sensory area at the base of the lagena
+known as the macula acustica basilaris, which is probably the first
+rudiment of a true cochlea. The ductus endolymphaticus has lost its
+communication with the skin, but it is frequently prolonged into the
+skull and along the spinal canal, from which it protrudes, through the
+intervertebral foramina, bulging into the coelom. This is the case in
+the common frog (A. Coggi, _Anat. Anz._ 5. Jahrg., 1890, p. 177). In
+this class the tympanum and Eustachian tube are first developed; the
+membrana tympani lies flush with the skin of the side of the head, and
+the sound-waves are transmitted from it to the internal ear by a single
+bony rod--the columella.
+
+In the Reptilia the internal ear passes through a great range of
+development. In the Chelonia and Ophidia the cochlea is as rudimentary
+as in the Amphibia, but in the higher forms (Crocodilia) there is a
+lengthened and slightly twisted cochlea, at the end of which the lagena
+forms a minute terminal appendage. At the same time indications of the
+scalae tympani and vestibuli appear. As in the Amphibia the ductus
+endolymphaticus sometimes extends into the cranial cavity and on into
+other parts of the body. Snakes have no tympanic membrane. In the birds
+the cochlea resembles that of the crocodiles, but the posterior
+semicircular canal is above the superior where they join one another. In
+certain lizards and birds (owls) a small fold of skin represents the
+first appearance of an external ear. In the monotremes the internal ear
+is reptilian in its arrangement, but above them the mammals always have
+a spirally twisted cochlea, the number of turns varying from one and a
+half in the Cetacea to nearly five in the rodent _Coelogenys_. The
+lagena is reduced to a mere vestige. The organ of Corti is peculiar to
+mammals, and the single columella of the middle ear is replaced by the
+three ossicles already described in Man (see Alban Doran, "Morphology of
+the Mammalian Ossicula auditus," _Proc. Linn. Soc._, 1876-1877, xiii.
+185; also _Trans. Linn. Soc._ 2nd Ser. Zool. i. 371). In some mammals,
+especially Carnivora, the middle ear is enlarged to form the tympanic
+bulla, but the mastoid cells are peculiar to Man.
+
+  For further details see G. Retzius, _Das Gehörorgan der Wirbelthiere_
+  (Stockholm, 1881-1884); Catalogue of the Museum of the R. College of
+  Surgeons--Physiological Series, vol. iii. (London, 1906); R.
+  Wiedersheim's _Vergleichende Anatomie der Wirbeltiere_ (Jena, 1902).
+       (F. G. P.)
+
+
+DISEASES OF THE EAR
+
+Modern scientific aural surgery and medicine (commonly known as Otology)
+dates from the time of Sir William Wilde of Dublin (1843), whose work
+marked a great advance in the application of anatomical, physiological
+and therapeutical knowledge to the study of this organ. Less noticeable
+contributions to the subject had not long before been made by Saunders
+(1827), Kramer (1833), Pilcher (1841) and Yearsley (1841). The next
+important event in the history of otology was the publication of J.
+Toynbee's book in 1860 containing his valuable anatomical and
+pathological observations. Von Tröltsch of Würzburg, following on the
+lines of Wilde and Toynbee, produced two well-known works in 1861 and
+1862, laying the foundation of the study in Germany. In that country and
+in Austria he was followed by Hermann Schwartze, Politzer, Gruber,
+Weber-Liel, Rüdinger, Moos and numerous others. France produced Itard,
+de la Charrière, Menière, Loewenberg and Bonnafont; and Belgium, Charles
+Delstanche, father and son. In Great Britain the work was carried on by
+James Hinton (1874), Peter Allen (1871), Patterson Cassells and Sir
+William Dalby. In America we may count among the early otologists Edward
+H. Clarke (1858), D.B. St John Roosa, H. Knapp, Clarence J. Blake,
+Albert H. Buck and Charles Burnett. Other workers all over the world are
+too numerous to mention.
+
+_Various Diseases and Injuries._--Diseases of the ear may affect any of
+the three divisions, the external, middle or internal ear. The commoner
+affections of the _auricle_ are eczema, various tumours (simple and
+malignant), and serous and sebaceous cysts. Haematoma auris
+(othaematoma), or effusion of blood into the auricle, is often due to
+injury, but may occur spontaneously, especially in insane persons. The
+chief diseases of the _external auditory canal_ are as follows:--impacted
+cerumen (or wax), circumscribed (or furuncular) inflammation, diffuse
+inflammation, strictures due to inflammatory affections, bony growths,
+fungi (otomycosis), malignant disease, caries and necrosis, and foreign
+bodies.
+
+Diseases of the _middle ear_ fall into two categories, suppurative and
+non-suppurative (i.e. with and without the formation of pus).
+Suppurative inflammation of the middle ear is either acute or chronic,
+and is in either case accompanied by perforation of the drum head and
+discharge from the ear. The chief importance of these affections, in
+addition to the symptoms of pain, deafness, discharge, &c., is the
+serious complications which may ensue from their neglect, viz. aural
+polypi, caries and necrosis of the bone, affections of the mastoid
+process, including the mastoid antrum, paralysis of the facial nerve,
+and the still more serious intracranial and vascular infective diseases,
+such as abscess in the brain (cerebrum or cerebellum), meningitis, with
+subdural and extradural abscesses, septic thrombosis of the sigmoid and
+other venous sinuses, and pyaemia. It is owing to the possibility of
+these complications that life insurance companies usually, and rightly,
+inquire as to the presence of ear discharge before accepting a life.
+Patterson Cassells of Glasgow urged this special point as long ago as
+1877. Acute suppurative disease of the middle ear is often due to the
+exanthemata, scarlatina, measles and smallpox, and to bathing and
+diving. It may also be caused by influenza, diphtheria and pulmonary
+phthisis.
+
+Non-suppurative disease of the middle ear may be acute or chronic. In
+the acute form the inflammation is less violent than in the acute
+suppurative inflammation, and is rarely accompanied by perforation.
+Chronic non-suppurative inflammation may be divided into the moist form,
+in which the symptoms are improved by inflation of the tympanum through
+the Eustachian tube, and the dry form (including sclerosis), which is
+more intractable and in which this procedure has little or no beneficial
+effect. Diseases of the _internal ear_ may be primary or secondary to an
+affection of the tympanum or to intracranial disease.
+
+Injuries to any part of the ear may occur, among the commoner being
+injuries to the auricle, rupture of the drum head (from explosions,
+blows on the ear or the introduction of sharp bodies into the ear
+canal), and injuries from fractured skull. Congenital malformations of
+the ear are most frequently met with in the auricle and external canal.
+
+_Methods of Examination._--The methods of examining the ear are roughly
+threefold:--(1) Testing the hearing with watch, voice and tuning-fork.
+The latter is especially used to distinguish between disease of the
+middle ear (conducting apparatus) and that of the internal ear
+(perceptive apparatus). Our knowledge of the subject has been brought to
+its present state by the labours of many observers, notably Weber,
+Rinne, Schwabach, Lucae and Gellé. (2) Examination of the canal and
+drum-head with speculum and reflector, introduced by Kramer, Wilde and
+von Tröltsch. (3) Examination of the drum-cavity through the Eustachian
+tube by the various methods of inflation.
+
+_Symptoms._--The chief symptoms of ear diseases are deafness, noises in
+the ear (tinnitus aurium), giddiness, pain and discharge. Deafness (or
+other disturbance of hearing) and noises may occur from disease in
+almost any part of the ear. Purulent discharge usually comes from the
+middle ear. Giddiness is more commonly associated with affections of the
+internal ear.
+
+_Treatment._--Ear diseases are treated on ordinary surgical and medical
+lines, due regard being had to the anatomical and physiological
+peculiarities of this organ of sense, and especially to its close
+relationship, on the one hand to the nose and naso-pharynx, and on the
+other hand to the cranium and its contents. The chief advance in aural
+surgery in recent years has been in the surgery of the mastoid process
+and antrum. The pioneers of this work were H. Schwartze of Halle, and
+Stacke of Erfurt, who have been followed by a host of workers in all
+parts of the world. This development led to increased attention being
+paid to the intracranial complications of suppurative ear disease, in
+the treatment of which great strides have been made in the last few
+years.
+
+_Effects of Diseases of the Nose on the Ear._--The influence of diseases
+of the nose and naso-pharynx on ear diseases was brought out by
+Loewenberg of Paris, Voltolini of Breslau, and especially by Wilhelm
+Meyer of Copenhagen, the discoverer of adenoid vegetations of the
+naso-pharynx ("adenoids"), who recognized the great importance of this
+disease and gave an inimitable account of it in the _Trans. of the Royal
+Medical and Chirurgical Society of London_, 1870, and the _Archiv für
+Ohrenheilkunde_, 1873. Adenoid vegetations, which consist of an abnormal
+enlargement of Luschka's tonsil in the vault of the pharynx, frequently
+give rise to ear disease in children, and, if not attended to, lay the
+foundation of nasal and ear troubles in after life. They are often
+associated with enlargement of the faucial tonsils.
+
+  _Journals._--In 1864 the _Archiv für Ohrenheilkunde_ was started by
+  Politzer and Schwartze, and, in 1867, the _Monatsschrift für
+  Ohrenheilkunde_ (a monthly publication) was founded by Voltolini,
+  Gruber, Weber-Liel and Rüdinger. Appearing first as the _Archives of
+  Ophthalmology and Otology_, simultaneously in English and German, in
+  1869, the _Archives of Otology_ became a separate publication under
+  the editorship of Knapp, Moos and Roosa in 1879. Amongst other
+  journals now existing are _Annales des maladies de l'oreille et du
+  larynx_ (Paris), _Journal of Laryngology_ (London), _Centralblatt für
+  Ohrenheilkunde_ (Leipzig), &c.
+
+  _Societies._--The earliest society formed was the American Otological
+  Society (1868), which held annual meetings and published yearly
+  transactions. Flourishing societies for the study of otology
+  (sometimes combined with laryngology) exist in almost all civilized
+  countries, and they usually publish transactions consisting of
+  original papers and cases. The Otological Society of the United
+  Kingdom was founded in 1900.
+
+  _International Congresses._--International Otological congresses have
+  been held at intervals of about four years at New York, Milan, Basel,
+  Brussels, Florence, London and Bordeaux (1904). The proceedings of the
+  congresses appear as substantial volumes.
+
+  _Hospitals._--The earliest record of a public institution for the
+  treatment of ear diseases is a Dispensary for Diseases of the Eye and
+  Ear in London, started by Saunders and Cooper, which existed in 1804;
+  the aural part, however, was soon closed, so that the actual oldest
+  institution appears to be the Royal Ear Hospital, London, which was
+  founded by Curtis in 1816. Four years later there was started the New
+  York Eye and Ear Infirmary. At the present time in every large town of
+  Europe and America ear diseases are treated either in separate
+  departments of general hospitals or in institutions especially devoted
+  to the purpose.
+
+  For a history of otology from the earliest times refer to _A Practical
+  Treatise on the Diseases of the Ear_, by D.B. St John Roosa, M.D.,
+  LL.D. (6th edition, New York, 1885), and for a general account of the
+  present state of otological science to _A Text-Book of the Diseases of
+  the Ear for Students and Practitioners_, by Professor Dr Adam
+  Politzer, transl. by Milton J. Ballin, Ph.B., M.D., and Clarence J.
+  Heller, M.D. (4th edition, London, 1902).     (E. C. B.*)
+
+
+
+
+EARL, a title and rank of nobility (corresponding to Lat. _comes_; Fr.
+_comte_), now the third in order of the British peerage, and accordingly
+intervening between marquess and viscount. Earl, however, is the oldest
+title and rank of English nobles, and was the highest until the year
+1337, when the Black Prince was created duke of Cornwall by Edward III.
+
+The nature of a modern earldom is readily understood, since it is a rank
+and dignity of nobility which, while it confers no official power or
+authority, is inalienable, indivisible, and descends in regular
+succession to all the heirs under the limitation in the grant until, on
+their failure, it becomes extinct.
+
+The title is of Scandinavian origin, and first appears in England under
+Canute as _jarl_, which was englished as _eorl_. Like the _ealdorman_,
+whose place he took, the _eorl_ was a great royal officer, who might be
+set over several counties, but who presided separately in the county
+court of each with the bishop of the diocese. Although there were counts
+in Normandy before the Norman Conquest, they differed in character from
+the English earls, and the earl's position appears to have been but
+slightly modified by the Conquest. He was still generally entitled to
+the "third penny" of the county, but his office tended, under Norman
+influence, to become an hereditary dignity and his sphere was restricted
+by the Conqueror to a single county. The right to the "third penny" is a
+question of some obscurity, but its possession seems to have been deemed
+the distinctive mark of an earl, while the girding with "the sword of
+the county" formed the essential feature in his creation or investiture,
+as it continued to do for centuries later. The fact that every earl was
+the earl of a particular county has been much obscured by the loose
+usage of early times, when the style adopted was sometimes that of the
+noble's surname (e.g. the Earls Ferrers), sometimes that of his chief
+seat (e.g. the Earls of Arundel), and sometimes that of the county.
+Palatine earldoms, or palatinates, were those which possessed _regalia_,
+i.e. special privileges delegated by the crown. The two great examples,
+which dated from Norman times, were Chester and Durham, where the earl
+and the bishop respectively had their own courts and jurisdiction, and
+were almost petty sovereigns.
+
+The earliest known charter creating an earl is that by which Stephen
+bestowed on Geoffrey de Mandeville, in or about 1140, the earldom of
+Essex as an hereditary dignity. Several other creations by Stephen and
+the empress Maud followed in quick succession. From at least the time of
+the Conquest the earl had a double character; he was one of the
+"barons," or tenants in chief, in virtue of the fief he held of the
+crown, as well as an earl in virtue of his "belting" (with the sword)
+and his "third penny" of the county. His fief would descend to the heirs
+of his body; and the earliest charters creating earldoms were granted
+with the same "limitation." The dignity might thus descend to a woman,
+and, in that case, like the territorial fief, it would be held by her
+husband, who might be summoned to parliament in right of it. The earldom
+of Warwick thus passed through several families till it was finally
+obtained, in 1449, by the Kingmaker, who had married the heiress of the
+former earls. But in the case of "co-heiresses" (more daughters than
+one), the king determined which, if any, should inherit the dignity.
+
+The 14th century saw some changes introduced. The earldom of March,
+created in 1328, was the first that was not named from a county or its
+capital town. Under Edward III. also an idea appears to have arisen that
+earldoms were connected with the tenure of lands, and in 1337 several
+fresh ones were created and large grants of lands made for their
+support. The first earldom granted with limitation to the heirs male of
+the grantee's body was that of Nottingham in 1383. Another innovation
+was the grant of the first earldom for life only in 1377. The girding
+with the sword was the only observance at a creation till the first year
+of Edward VI., when the imposition of the cap of dignity and a circlet
+of gold was added. Under James I. the patent of creation was declared to
+be sufficient without any ceremony. An earl's robe of estate has three
+bars of ermine, but possibly it had originally four.
+
+Something should be said of anomalous earldoms with Norman or Scottish
+styles. The Norman styles originated either under the Norman kings or at
+the time of the conquest of Normandy by the house of Lancaster. To the
+former period belonged that of Aumale, which successive fresh creations,
+under the Latinized form "Albemarle" have perpetuated to the present day
+(see ALBEMARLE, EARLS AND DUKES OF). The so-called earls of Eu and of
+Mortain, in that period, were really holders of Norman _comtés_. Henry
+V. and his son created five or six, it is said, but really seven at
+least, Norman countships or earldoms, of which Harcourt (1418), Perche
+(1419), Dreux (1427) and Mortain (? 1430) were bestowed on English
+nobles, Eu (1419), and Tankerville (1419) on English commoners, and
+Longueville (1419) on a foreigner, Gaston de Foix. Of these the earldom
+of "Eu" was assumed by the earls of Essex till the death of Robert, the
+parliament's general (1646), while the title of Tankerville still
+survives under a modern creation (1714). An anomalous royal licence of
+1661 permitted the earl of Bath to use the title of earl of Corbeil by
+alleged hereditary right. Of Scottish earldoms recognized in the English
+parliament the most remarkable case is that of the Lords Umfraville, who
+were summoned for three generations (1297-1380), as earls of Angus;
+Henry, Lord Beaumont, also was summoned as earl of Buchan from 1334 to
+1339.
+
+The earldom of Chester is granted to the princes of Wales on their
+creation, and the Scottish earldom of Carrick is held by the eldest son
+of the sovereign under act of parliament.
+
+The premier earldom is that of Arundel (q.v.), but as this is at present
+united with the dukedom of Norfolk, the oldest earldom not merged in a
+higher title is that of Shrewsbury (1442), the next in seniority being
+Derby (1485), and Huntingdon (1529). These three have been known as "the
+catskin earls," a term of uncertain origin. The ancient earldom of
+Wiltshire (1397) was unsuccessfully claimed in 1869 by Mr Scrope of
+Danby, and that of Norfolk (1312), in 1906, by Lord Mowbray and
+Stourton.
+
+The premier earldom of Scotland as recognized by the Union Roll (1707),
+is that of Crawford, held by the Lindsays since its creation in 1398;
+but it is not one of the ancient "seven earldoms." The Decreet of
+Ranking (1606) appears to have recognized the earldom of Sutherland as
+the most ancient in virtue of a charter of 1347, but the House of Lords'
+decision of 1771 recognized it as having descended from at least the
+year 1275, and it may be as old as 1228. It is at present united with
+the dukedom of Sutherland. The original "seven earldoms" (of which it
+was one) represented seven provinces, each of which was under a
+"_mormaer_." This Celtic title was rendered "_jarl_" by the Norsemen,
+and under Alexander I. (c. 1115) began to be replaced by earl (_comes_),
+owing to Anglo-Norman influence, which also tended to make these
+earldoms less official and more feudal.
+
+In Ireland the duke of Leinster is, as earl of Kildare, premier earl as
+well as premier duke.
+
+An earl is "Right Honourable," and is styled "My Lord." His eldest son
+bears his father's "second title," and therefore, that second title
+being in most cases a viscounty, he generally is styled "Viscount";
+where, as with Devon and Huntingdon, there is no second title, one may
+be assumed for convenience; under all circumstances, however, the eldest
+son of an earl takes precedence immediately after the viscounts. The
+younger sons of earls are "Honourable," but all their daughters are
+"Ladies." In formal documents and instruments, the sovereign, when
+addressing or making mention of any peer of the degree of an earl,
+usually designates him "trusty and well-beloved cousin,"--a form of
+appellation first adopted by Henry IV., who either by descent or
+alliance was actually related to every earl and duke in the realm. The
+wife of an earl is a countess; she is "Right Honourable," and is styled
+"My Lady." For the earl's coronet see CROWN AND CORONET.
+
+  See Lord's _Reports on the Dignity of a Peer_; Pike's _Constitutional_
+  _History of the House of Lords_; Selden's _Titles of Honour_; G.E.
+  C(okayne)'s _Complete Peerage_; Round's _Geoffrey de Mandeville_.
+       (J. H. R.)
+
+
+
+
+EARLE, JOHN (c. 1601-1665), English divine, was born at York about 1601.
+He matriculated at Christ Church, Oxford, but migrated to Merton, where
+he obtained a fellowship. In 1631 he was proctor and also chaplain to
+Philip, earl of Pembroke, then chancellor of the university, who
+presented him to the rectory of Bishopston in Wiltshire. His fame
+spread, and in 1641 he was appointed chaplain and tutor to Prince
+Charles. In 1643 he was elected one of the Assembly of Divines at
+Westminster, but his sympathies with the king and with the Anglican
+Church were so strong that he declined to sit. Early in 1643 he was
+chosen chancellor of the cathedral of Salisbury, but of this preferment
+he was soon deprived as a "malignant." After Cromwell's great victory at
+Worcester, Earle went abroad, and was named clerk of the closet and
+chaplain to Charles II. He spent a year at Antwerp in the house of Isaac
+Walton's friend, George Morley, who afterwards became bishop of
+Winchester. He next joined the duke of York (James II.) at Paris,
+returning to England at the Restoration. He was at once appointed dean
+of Westminster, and in 1661 was one of the commissioners for revising
+the liturgy. He was on friendly terms with Richard Baxter. In November
+1662 he was consecrated bishop of Worcester, and was translated, ten
+months later, to the see of Salisbury, where he conciliated the
+nonconformists. He was strongly opposed to the Conventicle and Five Mile
+Acts. During the great plague Earle attended the king and queen at
+Oxford, and there he died on the 17th of November 1665.
+
+Earle's chief title to remembrance is his witty and humorous work
+entitled _Microcosmographie, or a Peece of the World discovered, in
+Essayes and Characters_, which throws light on the manners of the time.
+First published anonymously in 1628, it became very popular, and ran
+through ten editions in the lifetime of the author. The style is quaint
+and epigrammatic; and the reader is frequently reminded of Thomas Fuller
+by such passages as this: "A university dunner is a gentlemen follower
+cheaply purchased, for his own money has hyr'd him." Several reprints of
+the book have been issued since the author's death; and in 1671 a French
+translation by J. Dymock appeared with the title of _Le Vice ridiculé_.
+Earle was employed by Charles II. to make the Latin translation of the
+_Eikon Basilike_, published in 1649. A similar translation of R.
+Hooker's _Ecclesiastical Polity_ was accidentally destroyed.
+
+"Dr Earle," says Lord Clarendon in his _Life_, "was a man of great piety
+and devotion, a most eloquent and powerful preacher, and of a
+conversation so pleasant and delightful, so very innocent, and so very
+facetious, that no man's company was more desired and loved. No man was
+more negligent in his dress and habit and mien, no man more wary and
+cultivated in his behaviour and discourse. He was very dear to the Lord
+Falkland, with whom he spent as much time as he could make his own."
+
+  See especially Philip Bliss's edition of the _Microcosmographie_
+  (London, 1811), and E. Arber's Reprint (London, 1868).
+
+
+
+
+EARLE, RALPH (1751-1801), American historical and portrait painter, was
+born at Leicester, Massachusetts, on the 11th of May 1751. Like so many
+of the colonial craftsmen, Earle was self-taught, and for many years was
+an itinerant painter. He went with the Governor's Guard to Lexington and
+made battle sketches, from which in 1775 he painted four scenes,
+engraved by Amos Doolittle, which are probably the first historical
+paintings by an American. After the War of Independence, Earle went to
+London, entered the studio of Benjamin West, and painted the king and
+many notables. After his return to America in 1786 he made portraits of
+Timothy Dwight, Governor Caleb Strong, Roger Sherman, and other
+prominent men. He also painted a large picture of Niagara Falls. He died
+at Bolton, Connecticut, on the 16th of August 1801.
+
+
+
+
+EARL MARSHAL, in England, a functionary who ranks as the eighth of the
+great officers of state. He is the head of the college of arms, and has
+the appointment of the kings-of-arms, heralds and pursuivants at his
+discretion. He attends the sovereign in opening and closing the session
+of parliament, walking opposite to the lord great chamberlain on his or
+her right hand. It is his duty to make arrangements for the order of all
+state processions and ceremonials, especially for coronations and royal
+marriages and funerals. Like the lord high constable he rode into
+Westminster Hall with the champion after a coronation, till the
+coronation banquet was abandoned, taking his place on the left hand, and
+with the lord great chamberlain he assists at the introduction of all
+newly-created peers into the House of Lords.
+
+The marshal appears in the feudal armies to have been in command of the
+cavalry under the constable, and to have in some measure superseded him
+as master of the horse in the royal palace. He exercised joint and
+co-ordinate jurisdiction with the constable in the court of chivalry,
+and afterwards became the sole judge of that tribunal till its
+obsolescence. The marshalship of England was formerly believed to have
+been inherited from the Clares by the Marshal family, who had only been
+marshals of the household. It was held, however, by the latter family,
+as the office of chief (_magister_) marshal, as early as the days of
+Henry I. Through them, under Henry III., it passed to the Bigods, as
+their eldest co-heirs. In 1306 it fell to the crown on the death of the
+last Bigod, earl of Norfolk, who had made Edward I. his heir, and in
+1316 it was granted by Edward II. to his own younger brother, Thomas "of
+Brotherton," earl of Norfolk. As yet the style of the office was only
+"marshal" although the last Bigod holder, being an earl, was sometimes
+loosely spoken of as the earl marshal. The office, having reverted to
+the crown, was granted out anew by Richard II., in 1385, to Thomas
+Mowbray, earl of Nottingham, the representative of Thomas "of
+Brotherton." In 1386 the style of "earl marshal" was formally granted to
+him in addition. After several attainders and partial restorations in
+the reigns of the Tudors and the Stuarts, the earl marshalship was
+granted anew to the Howards by Charles II. in 1672 and entailed on their
+male line, with many specific remainders and limitations, under which
+settlement it has regularly descended to the present duke of Norfolk.
+Its holders, however, could not execute the office until the Roman
+Catholic emancipation, and had to appoint deputies. The duke is styled
+earl marshal "and hereditary marshal of England," but the double style
+would seem to be an error, though the Mowbrays, with their double
+creation (1385, 1386) might have claimed it. His Grace appends the
+letters "E.M." to his signature, and bears behind his shield two batons
+crossed in saltire, the marshal's rod (_virga_) having been the badge of
+the office from Norman times. There appear to have been hereditary
+marshals of Ireland, but their history is not well ascertained. The
+Keiths were Great Marischals of Scotland from at least the days of
+Robert Bruce, and were created earls marischal in or about 1458, but
+lost both earldom and office by the attainder of George, the 10th earl,
+in 1716. (See also MARSHAL; STATE, GREAT OFFICERS OF.)
+
+  See "The Marshalship of England," in J.H. Round, _Commune of London
+  and Other Studies_ (London, 1899); G.E. C(okayne)'s _Complete
+  Peerage_.     (J. H. R.)
+
+
+
+
+EARLOM, RICHARD (1742-1822), English mezzotint engraver, was born and
+died in London. His natural faculty for art appears to have been first
+called into exercise by admiration for the lord mayor's state coach,
+just decorated by Cipriani. He tried to copy the paintings, and was sent
+to study under Cipriani. He displayed great skill as a draughtsman, and
+at the same time acquired without assistance the art of engraving in
+mezzotint. In 1765 he was employed by Alderman Boydell, then one of the
+most liberal promoters of the fine arts, to make a series of drawings
+from the pictures at Houghton Hall; and these he afterwards engraved in
+mezzotint. His most perfect works as engraver are perhaps the fruit and
+flower pieces after the Dutch artists Van Os and Van Huysum. Amongst his
+historical and figure subjects are--"Agrippina," after West; "Love in
+Bondage," after Guido Reni; the "Royal Academy," the "Embassy of
+Hyderbeck to meet Lord Cornwallis," and a "Tiger Hunt," the last three
+after Zoffany; and "Lord Heathfield," after Sir Joshua Reynolds. Earlom
+also executed a series of 200 facsimiles of the drawings and sketches
+of Claude Lorraine, which was published in 3 vols. folio, under the
+title of _Liber veritatis_ (1777-1819).
+
+
+
+
+EARLSTON (formerly ERCILDOUNE, of which it is a corruption), a parish
+and market town of Berwickshire, Scotland. Pop. (1901) 1049. It is
+situated on Leader Water in Lauderdale, 72½ m. S.E. of Edinburgh by the
+North British railway branch line from Reston Junction to St Boswells,
+and about 4 m. N.E. of Melrose. When the place was a hamlet of rude huts
+it was called Arcioldun or "Prospect Fort," with reference to Black Hill
+(1003 ft.), on the top of which may yet be traced the concentric rings
+of the British fort by which it was crowned. It is said to be possible
+to make out the remains of the cave-dwellings of the Ottadeni, the
+aborigines of the district. In the 12th and 13th centuries the Lindsays
+and the earls of March and Dunbar were the chief baronial families. The
+particular link with the remote past, however, is the ivy-clad ruin of
+the ancient tower, "The Rhymer's Castle," the traditional residence of
+Thomas Learmont, commonly called Thomas of Ercildoune, or Thomas the
+Rhymer, poet and prophet, and friend of the Fairies, who was born here
+about 1225. Rhymer's Tower was crumbling to pieces, and its stones were
+being used in the erection of dykes, cottages and houses, when the
+Edinburgh Border Counties Association acquired the relic and surrounding
+lands in 1895, and took steps to prevent further spoliation and decay.
+The leading manufactures are ginghams, tweeds and shirtings, and the
+town is also an important agricultural centre, stock sales taking place
+at regular intervals and cattle and horse fairs being held every year.
+Some 3 m. away is the estate of Bemersyde, said to have been in the
+possession of the Haigs for nearly 1000 years. The prospect from
+Bemersyde Hill was Sir Walter Scott's favourite view. The castle at
+Bemersyde was erected in 1535 to secure the peace of the Border.
+
+
+
+
+EARLY, JUBAL ANDERSON (1816-1894), American soldier and lawyer, was born
+in Franklin county, Virginia, on the 3rd of November 1816, and graduated
+at the U.S. Military Academy in 1837. He served in the Seminole War of
+1837-38, after which he resigned in order to practise law in Franklin
+county, Va. He also engaged in state politics, and served in the Mexican
+War as a major of Virginia volunteers. He was strongly opposed to
+secession, but thought it his duty to conform to the action of his
+state. As a colonel in the Confederate army, he rendered conspicuous
+service at the first battle of Bull Run (q.v.). Promoted
+brigadier-general, and subsequently major-general, Early served
+throughout the Virginian campaigns of 1862-63, and defended the lines of
+Fredericksburg during the battle of Chancellorsville. At Gettysburg he
+commanded his division of Ewell's corps. In the campaign of 1864 Early,
+who had now reached the rank of lieutenant-general, commanded the
+Confederate forces in the Shenandoah Valley. The action of Lynchburg
+left him free to move northwards, his opponent being compelled to march
+away from the Valley. Early promptly utilized his advantage, crossed the
+Potomac, and defeated, on the Monocacy, all the troops which could be
+gathered to meet him. He appeared before the lines of Washington, put
+part of Maryland and Pennsylvania under contribution, and only retired
+to the Valley when threatened by heavy forces hurriedly sent up to
+Washington. He then fought a successful action at Winchester, reappeared
+on the Potomac, and sent his cavalry on a raid into Pennsylvania. A
+greatly superior army was now formed under General Sheridan to oppose
+Early. In spite of his skill and energy the Confederate leader was
+defeated in the battles of Winchester and Fisher's Hill. Finally, on the
+19th of October, after inflicting at first a severe blow upon the
+Federal army in its camps on Cedar Creek, he was decisively beaten by
+Sheridan. (See SHENANDOAH VALLEY CAMPAIGNS.) Waynesboro (March 1865) was
+his last fight, after which he was relieved from his command. General
+Early was regarded by many as the ablest soldier, after Lee and Jackson,
+in the Army of Northern Virginia, and one of the ablest in the whole
+Confederate army. That he failed to make headway against an army far
+superior in numbers, and led by a general of the calibre of Sheridan,
+cannot be held to prove the falsity of this judgment. After the peace
+he went to Canada, but in 1867 returned to resume the practice of law.
+For a time he managed in conjunction with General Beauregard the
+Louisiana lottery. He died at Lynchburg, Va., on the 2nd of March 1894.
+General Early was for a time president of the Southern Historical
+Society, and wrote, besides various essays and historical papers, _A
+Memoir of the Last Year of the War, &c._ (1867).
+
+
+
+
+EARLY ENGLISH PERIOD, in architecture, the term given by Rickman to the
+first pointed or Gothic style in England, nominally 1189-1307, which
+succeeded the Romanesque or Norman period towards the end of the 12th
+century, and developed into the Decorated period in the commencement of
+the 14th century. It is chiefly characterized by the almost universal
+employment of the pointed arch, not only in arches of wide span such as
+those of the nave arcade, but for doorways and windows. The actual
+introduction of the pointed arch took place at a much earlier date, as
+in the nave arcade of the Cistercian Abbey of Buildwas (1140), though
+the clerestory window above has semicircular arches. It is customary,
+therefore, to make allowance for a transitional epoch from the middle of
+the 12th century. Although the pointed arches used are sometimes
+equilateral and sometimes drop-arches, the lancet-arch is the most
+characteristic. The period is best recognized in England by the great
+depth given to the hollows of the mouldings, alternating with fillets
+and rolls, by the decoration of the hollows with the dog-tooth ornament,
+by the circular abacus of the capitals, and the employment of slender
+detached shafts of Purbeck marble which are attached to piers by
+circular moulded shaft-rings (Fr. _anneau_).
+
+The arches are sometimes cusped; circles with trefoils, quatrefoils,
+&c., are introduced into the tracery, and large rose windows in the
+transept or nave, as at Lincoln (1220). The conventional foliage
+decorating the capitals is of great beauty and variety, and extends to
+spandrils, bosses, &c. In the spandrils of the arches of the nave,
+transept or choir arcades, diaper work is occasionally found, as in the
+transept of Westminster Abbey. The latter is one of the chief examples
+of the period, to which must be added the cathedral of Salisbury (except
+the tower); the Galilee at Ely; nave and transept of Wells (1225-1240);
+nave of Lincoln; west front of Peterborough; and the minster at
+Beverley.     (R. P. S.)
+
+
+
+
+EARN, the name of a loch and river in Perthshire, Scotland. The loch,
+lying almost due east and west, is 6½ m. long and {4/5} m. in maximum
+breadth, 287 ft. deep, with a mean depth of 138 ft., covers an area of
+nearly 4 sq. m., has a drainage basin of over 54½ sq. m., and stands 317
+ft. above the sea. Its waters are said never to freeze. It discharges by
+the river Earn. The points of interest on its shores are Lochearnhead
+(at the southern extremity of Glen Ogle), which has a station on the
+Callander-Oban railway, and the ruins of St Blane's chapel; Edinample
+Castle, an old turreted mansion belonging to the marquess of
+Breadalbane, situated in well-wooded grounds near the pretty falls of
+the Ample; Ardvorlich House, the original of Darlinvarach in Scott's
+_Legend of Montrose_, and the village of St Fillans at the foot of the
+loch, once the terminus of the branch of the Caledonian railway from
+Perth. The river flows out of Loch Earn, pursues an eastward course with
+a gentle inclination towards the south, and reaches the Firth of Tay, 6½
+m. below Perth, after a total run of 49 m. Its chief tributaries on the
+right are the Ruchil, Machany, Ruthven, May and Farg, and on the left,
+the Lednock and Turret. It is navigable by vessels of 50 tons as far up
+as Bridge of Earn, and is a notable fishing stream, abounding with
+salmon and trout, perch and pike being also plentiful. On the Lednock
+are the falls of the Devil's Cauldron and on the Turret and its feeders
+several graceful cascades. The principal places of interest on the banks
+of the Earn are Dunira, the favourite seat of Henry Dundas, 1st Viscount
+Melville, who took the title of his barony from the estate and to whose
+memory an obelisk was raised on the adjoining hill of Dunmore; the
+village of Comrie; the town of Crieff; the ruined castle of
+Innerpeffray, founded in 1610 by the 1st Lord Maderty, close to which is
+the library founded in 1691 by the 3rd Lord Maderty, containing some
+rare black-letter books and the Bible that belonged to the marquess of
+Montrose; Gascon Hall, now in ruins, but with traditions reaching back
+to the days of Wallace; Dupplin Castle, a fine Tudor mansion, seat of
+the earl of Kinnoull, who derives from it the title of his viscounty;
+Aberdalgie, Forgandenny and Bridge of Earn, a health resort situated
+amidst picturesque surroundings. Strathearn, as the valley of the Earn
+is called, extending from the loch to the Firth of Tay, is a beautiful
+and, on the whole, fertile tract, though liable at times to heavy
+floods. The earl of Perth is hereditary steward of Strathearn.
+
+
+
+
+EARNEST (probably a corruption of the obsolete _arles_ or _erles_,
+adapted from Lat. equivalent _arrha_, due to a confusion with the
+adjective "earnest," serious, O. Eng. _eornust_, cognate with Ger.
+_ernst_), the payment of a sum of money by the buyer of goods to the
+seller on the conclusion of a bargain as a pledge for its due
+performance. It is almost similar to the _arrha_ of the Roman law, which
+may be traced back in the history of legal institutions to a period when
+the validity of a contract depended not so much upon the real intention
+of the parties, as upon the due observance of a prescribed ceremony. But
+_earnest_ was never part payment, which _arrha_ might have been. Apart
+from its survival as a custom, its chief importance in English law is
+its recognition by the Statute of Frauds as giving validity to contracts
+for the sale of goods of a value exceeding £10 (see SALE OF GOODS). It
+is in that statute clearly distinguished from part payment, consequently
+any sum, however small, would be sufficient as earnest, being given as a
+token that the contract is binding and should be expressly stated so by
+the giver. The giving of earnest, or _hand-money_, as it is sometimes
+called, has now fallen into very general disuse.
+
+
+
+
+EAR-RING, an ornament worn pendent from the ear, and generally suspended
+(especially among the more civilized races) by means of a ring or hook
+passing through the pendulous lobe of the ear. Among savage races the
+impulse to decorate, or at any rate to modify the appearance of the ear,
+is almost universal. With such peoples the ear appendage is chiefly
+remarkable for its extravagant dimensions. Many examples may be seen in
+the ethnographic galleries of the British Museum. The Berawan people of
+Borneo use plugs through the lobe of the ear 3¾ in. in diameter. More
+extraordinary still is an example of a stone ear-plug worn by a Masai,
+4½ in. in diameter and weighing 2 lb. 14 oz. (_Man_, 1905, p. 22). It is
+stated that according to the Masai standard of fashion, the lobes of the
+ears should be enlarged so as to be capable of meeting above the head.
+Among the superior races, though ear ornaments of extravagant size and
+elaboration are not unknown, moderation in size is commonly observed,
+and greater attention is paid to workmanship and fineness of material.
+
+The general usage appears to have been to have ear-rings worn in pairs,
+the two ornaments in all respects resembling each other; in ancient
+times, or more recently among Oriental races, a single ear-ring has
+sometimes been worn. The use of this kind of ornament, which constantly
+was of great value, dates from the remotest historical antiquity, the
+earliest mention of ear-rings occurring in the book of Genesis. It
+appears probable that the ear-rings of Jacob's family, which he buried
+with his strange idols at Bethel, were regarded as amulets or talismans,
+such unquestionably being the estimation in which some ornaments of this
+class have been held from a very early period, as they still are held in
+the East. Thus in New Zealand ear-rings are decorated with the teeth of
+enemies, and with talismanic sharks' teeth. Among all the Oriental races
+of whom we have any accurate knowledge, the Hebrews and Egyptians
+excepted, ear-rings always have been in general use by both sexes; while
+in the West, as well as by the Hebrews and Egyptians, as a general rule
+they have been considered exclusively female ornaments. By the Greeks
+and Romans also ear-rings were worn only by women, and the wearing of
+them by a man is often spoken of as distinctively oriental.
+
+[Illustration: From _La Grande Encyclopédie_.
+
+FIG. 1.--Ear-ring from an Assyrian bas relief.]
+
+In archaic art, ear-rings are frequently represented or their traces are
+left in the perforated ear lobes of early statues. After the 4th century
+such perforations occur seldom. In one instance, a Greek inscription
+records the weight of the detachable gold ornaments on a statue, among
+which a pair of ear-rings is included. Ear-rings of characteristic form
+are frequently discovered by excavation. In Egypt, a system of pendent
+chains is found hanging from a disk. In Assyria the decoration consists
+of pendants or knobs attached to a rigid ring. In the early civilization
+represented by Dr Schliemann's Trojan investigations, pieces of gold
+plate are suspended by parallel chains. In the Mycenaean period,
+ear-rings are infrequent in Greece, but have been found in abundance in
+the Mycenaean finds of Enkomi (Cyprus) in the form of pendent
+bulls'-heads, or of decorative forms based on the bull's head. In the
+tombs of the Greek settlers in the Crimea (4th century B.C.), ear-rings
+are found of marvellous complexity and beauty. The lexicographer Pollux,
+speaking of the names given to ear-rings, derived from their forms,
+mentions caryatids, hippocamps and centauresses. Jewels of the same
+class, of exquisite beauty and of workmanship that is truly wonderful,
+have been rescued from the sepulchres of ancient Etruria. Ear-rings of
+comparatively simple forms, but set with pearls and other stones, were
+the mode in Rome. In some instances, the stones were of fabulous value.
+During the Byzantine period they once more attained an extravagant size.
+Researches among the burial places of Anglo-Saxon Britain have led to
+the discovery of jewels in considerable numbers, which among their
+varieties include ear-rings executed in a style that proves the
+Anglo-Saxons to have made no inconsiderable advances in the arts of
+civilization.
+
+[Illustration: From _La Grande Encyclopédie_.
+
+FIG. 2.--Thetis crossing the sea, with the armour of Achilles. Ear-ring
+from the Crimea, Hermitage museum.]
+
+These same ornaments, which never have fallen into disuse, enjoy at the
+present day a considerable degree of favour, and the tide of fashion has
+set towards their increased use. Like all other modern jewels, however,
+the ear-rings of our own times as works of art can claim no historical
+attributes, because they consist as well of reproductions from all past
+ages and of every race as of fanciful productions that certainly can be
+assigned to no style of art whatever. As one of the curiosities of the
+subject it may be mentioned that Antonia, wife of Drusus, is said by
+Pliny to have attached a pair of ear-rings to her pet lamprey.
+
+
+
+
+EARTH (a word common to Teutonic languages, cf. Ger. _Erde_, Dutch
+_aarde_, Swed. and Dan. _jord_; outside Teutonic it appears only in the
+Gr. [Greek: eraze], on the ground; it has been connected by some
+etymologists with the Aryan root _ar-_, to plough, which is seen in the
+Lat. _arare_, obsolete Eng. "ear," and Gr. [Greek: aroun], but this is
+now considered very doubtful; see G. Curtius, _Greek Etymology_, Eng.
+trans., i. 426; Max Müller, _Lectures_, 8th ed. i. 294). From early
+times the word "earth" has been used in several connexions--from that of
+soil or ground to that of the planet which we inhabit, but it is
+difficult to trace the exact historic sequence of the diverse usages. In
+the cosmogony of the Pythagoreans, Platonists and other philosophers,
+the term or its equivalent denoted an element or fundamental quality
+which conferred upon matter the character of earthiness; and in the
+subsequent development of theories as to the ultimate composition of
+matter by the alchemists, iatrochemists, and early phlogistonists an
+element of the same name was retained (see ELEMENT). In modern
+chemistry, the common term "earth" is applied to certain oxides:--the
+"alkaline earths" (q.v.) are the oxides of calcium (lime), barium
+(baryta) and strontium (strontia); the "rare earths" (q.v.) are the
+oxides of a certain class of rare metals.
+
+
+THE EARTH
+
+The terrestrial globe is a member of the Solar system, the third in
+distance from the Sun, and the largest within the orbit of Jupiter. In
+the wider sense it may be regarded as composed of a gaseous atmosphere
+(see METEOROLOGY), which encircles the crust or lithosphere (see
+GEOGRAPHY), and surface waters or hydrosphere (see OCEAN AND
+OCEANOGRAPHY). The description of the surface features is a branch of
+Geography, and the discussions as to their origin and permanence belongs
+to Physiography (in the narrower sense), physiographical geology, or
+physical geography. The investigation of the crust belongs to geology
+and of rocks in particular to petrology.
+
+In the present article we shall treat the subject matter of the Earth as
+a planet under the following headings:--(1) Figure and Size, (2) Mass
+and Density, (3) Astronomical Relations, (4) Evolution and Age. These
+subjects will be treated summarily, readers being referred to the
+article ASTRONOMY and to the cross-references for details.
+
+1. _Figure and Size._--To primitive man the Earth was a flat disk with
+its surface diversified by mountains, rivers and seas. In many
+cosmogonies this disk was encircled by waters, unmeasurable by man and
+extending to a junction with the sky; and the disk stood as an island
+rising up through the waters from the floor of the universe, or was
+borne as an immovable ship on the surface. Of such a nature was the
+cosmogony of the Babylonians and Hebrews; Homer states the same idea,
+naming the encircling waters [Greek: Ôkeanos]; and Hesiod regarded it as
+a disk midway between the sky and the infernal regions. The theory that
+the Earth extended downwards to the limit of the universe was subjected
+to modification when it was seen that the same sun and stars reappeared
+in the east after their setting in the west. But man slowly realized
+that the earth was isolated in space, floating freely as a balloon, and
+much speculation was associated about that which supported the Earth.
+Tunnels in the foundations to permit the passage of the sun and stars
+were suggested; the Greeks considered twelve columns to support the
+heavens, and in their mythology the god Atlas appears condemned to
+support the columns; while the Egyptians had the Earth supported by four
+elephants, which themselves stood on a tortoise swimming on a sea.
+Earthquakes were regarded as due to a movement of these foundations; in
+Japan this was considered to be due to the motion of a great spider, an
+animal subsequently replaced by a cat-fish; in Mongolia it is a hog; in
+India, a mole; in some parts of South America, a whale; and among some
+of the North American Indians, a giant tortoise.
+
+The doctrine of the spherical form has been erroneously assigned to
+Thales; but he accepted the Semitic conception of the disk, and regarded
+the production of springs after earthquakes as due to the inrushing of
+the waters under the Earth into fissures in the surface. His pupil,
+Anaximander (610-547), according to Diogenes Laërtius, believed it to be
+spherical (see _The Observatory_, 1894, P. 208); and Anaximenes probably
+held a similar view. The spherical form is undoubtedly a discovery of
+Pythagoras, and was taught by the Pythagoreans and by the Eleatic
+Parmenides. The expositor of greatest moment was Aristotle; his
+arguments are those which we employ to-day:--the ship gradually
+disappearing from hull to mast as it recedes from the harbour to the
+horizon; the circular shadow cast by the Earth on the Moon during an
+eclipse, and the alteration in the appearance of the heavens as one
+passes from point to point on the Earth's surface.[1] He records
+attempts made to determine the circumference; but the first scientific
+investigation in this direction was made 150 years later by
+Eratosthenes. The spherical form, however, only became generally
+accepted after the Earth's circumnavigation (see GEOGRAPHY).
+
+The historical development of the methods for determining the figure of
+the Earth (by which we mean a theoretical surface in part indicated by
+the ocean at rest, and in other parts by the level to which water freely
+communicating with the oceans by canals traversing the land masses would
+rise) and the mathematical investigation of this problem are treated in
+the articles EARTH, FIGURE OF THE, and GEODESY; here the results are
+summarized. Sir Isaac Newton deduced from the mechanical consideration
+of the figure of equilibrium of a mass of rotating fluid, the form of an
+oblate spheroid, the ellipticity of a meridian section being {1/231},
+and the axes in the ratio 230 : 231. Geodetic measurements by the
+Cassinis and other French astronomers pointed to a prolate form, but the
+Newtonian figure was proved to be correct by the measurement of
+meridional arcs in Peru and Lapland by the expeditions organized by the
+French Academy of Sciences. More recent work points to an elliptical
+equatorial section, thus making the earth pear-shaped. The position of
+the longer axis is somewhat uncertain; it is certainly in Africa, Clarke
+placing it in longitude 8° 15' W., and Schubert in longitude 41° 4' E.;
+W.J. Sollas, arguing from terrestrial symmetry, has chosen the position
+lat. 6° N., long. 28° E., i.e. between Clarke's and Schubert's
+positions. For the lengths of the axes and the ellipticity of the Earth,
+see EARTH, FIGURE OF THE.
+
+2. _Mass and Density._--The earliest scientific investigation on the
+density and mass of the Earth (the problem is really single if the
+volume of the Earth be known) was made by Newton, who, mainly from
+astronomical considerations, suggested the limiting densities 5 and 6;
+it is remarkable that this prophetic guess should be realized, the mean
+value from subsequent researches being about 5½, which gives for the
+mass the value 6 × 10^21 tons. The density of the Earth has been
+determined by several experimenters within recent years by methods
+described in the article GRAVITATION; the most probable value is there
+stated to be 5.527.
+
+3. _Astronomical Relations._--The grandest achievements of astronomical
+science are undoubtedly to be associated with the elucidation of the
+complex motion of our planet. The notion that the Earth was fixed and
+immovable at the centre of an immeasurable universe long possessed the
+minds of men; and we find the illustrious Ptolemy accepting this view in
+the 2nd century A.D., and rejecting the notion of a rotating Earth--a
+theory which had been proposed as early as the 5th century B.C. by
+Philolaus on philosophical grounds, and in the 3rd century B.C. by the
+astronomer Aristarchus of Samos. He argued that if the Earth rotated
+then points at the equator had the enormous velocity of about 1000 m.
+per hour, and as a consequence there should be terrific gales from the
+east; the fact that there were no such gales invalidated, in his
+opinion, the theory. The Ptolemaic theory was unchallenged until 1543,
+in which year the _De Revolutionibus orbium Celestium_ of Copernicus was
+published. In this work it was shown that the common astronomical
+phenomena could be more simply explained by regarding the Earth as
+annually revolving about a fixed Sun, and daily rotating about itself. A
+clean sweep was made of the geocentric epicyclic motions of the planets
+which Ptolemy's theory demanded, and in place there was substituted a
+procession of planets about the Sun at different distances. The
+development of the Copernican theory--the corner-stone of modern
+astronomy--by Johann Kepler and Sir Isaac Newton is treated in the
+article ASTRONOMY: _History_; here we shall summarily discuss the
+motions of our planet and its relation to the solar system.
+
+The Earth has two principal motions--revolution about the Sun, rotation
+about its axis; there are in addition a number of secular motions.
+
+_Revolution._--The Earth revolves about the Sun in an elliptical orbit
+having the Sun at one focus. The plane of the orbit is termed the
+ecliptic; it is inclined to the Earth's equator at an angle termed the
+obliquity, and the points of intersection of the equator and ecliptic
+are termed the equinoctial points. The major axis of the ellipse is the
+line of apsides; when the Earth is nearest the Sun it is said to be in
+perihelion, when farthest it is in aphelion. The mean distance of the
+Earth from the Sun is a most important astronomical constant, since it
+is the unit of linear measurement; its value is about 93,000,000 m., and
+the difference between the perihelion and aphelion distances is about
+3,000,000 m. The eccentricity of the orbit is 0.016751. A tabular
+comparison of the orbital constants of the Earth and the other planets
+is given in the article PLANET. The period of revolution with regard to
+the Sun, or, in other words, the time taken by the Sun apparently to
+pass from one equinox to the same equinox, is the tropical or
+equinoctial year; its length is 365 d. 5 hrs. 48 m. 46 secs. It is about
+20 minutes shorter than the true or sidereal year, which is the time
+taken for the Sun apparently to travel from one star to it again. The
+difference in these two years is due to the secular variation termed
+precession (see below). A third year is named the _anomalistic year_,
+which is the time occupied in the passage from perihelion to perihelion;
+it is a little longer than the sidereal.
+
+_Rotation._--The Earth rotates about an axis terminating at the north
+and south geographical poles, and perpendicular to the equator; the
+period of rotation is termed the day (q.v.), of which several kinds are
+distinguished according to the body or point of reference. The rotation
+is performed from west to east; this daily rotation occasions the
+_diurnal_ motion of the celestial sphere, the rising of the Sun and
+stars in the east and their setting in the west, and also the phenomena
+of day and night. The inclination of the axis to the ecliptic brings
+about the presentation of places in different latitudes to the more
+direct rays of the sun; this is revealed in the variation in the length
+of daylight with the time of the year, and the phenomena of seasons.
+
+Although the rotation of the Earth was an accepted fact soon after its
+suggestion by Copernicus, an experimental proof was wanting until 1851,
+when Foucault performed his celebrated pendulum experiment at the
+Pantheon, Paris. A pendulum about 200 ft. long, composed of a flexible
+wire carrying a heavy iron bob, was suspended so as to be free to
+oscillate in any direction. The bob was provided with a style which
+passed over a table strewn with fine sand, so that the style traced the
+direction in which the bob was swinging. It was found that the
+oscillating pendulum never retraced its path, but at each swing it was
+apparently deviated to the right, and moreover the deviations in equal
+times were themselves equal. This means that the floor of the Pantheon
+was moving, and therefore the Earth was rotating. If the pendulum were
+swung in the southern hemisphere, the deviation would be to the left; if
+at the equator it would not deviate, while at the poles the plane of
+oscillation would traverse a complete circle in 24 hours.
+
+The rotation of the Earth appears to be perfectly uniform, comparisons
+of the times of transits, eclipses, &c., point to a variation of less
+than {1/100}th of a second since the time of Ptolemy. Theoretical
+investigations on the phenomena of tidal friction point, however, to a
+retardation, which may to some extent be diminished by the accelerations
+occasioned by the shrinkage of the globe, and some other factors
+difficult to evaluate (see TIDE).
+
+We now proceed to the secular variations.
+
+_Precession._--The axis of the earth does not preserve an invariable
+direction in space, but in a certain time it describes a cone, in much
+the same manner as the axis of a top spinning out of the vertical. The
+equator, which preserves approximately the same inclination to the
+ecliptic (there is a slight variation in the obliquity which we shall
+mention later), must move so that its intersections with the ecliptic,
+or equinoctial points, pass in a retrograde direction, i.e. opposite to
+that of the Earth. This motion is termed the precession of the
+equinoxes, and was observed by Hipparchus in the 2nd century B.C.;
+Ptolemy corrected the catalogue of Hipparchus for precession by adding
+2° 40' to the longitudes, the latitudes being unaltered by this motion,
+which at the present time is 50.26" annually, the complete circuit being
+made in about 26,000 years. Owing to precession the signs of the zodiac
+are traversing paths through the constellations, or, in other
+words, the constellations are continually shifting with regard to the
+equinoctial points; at one time the vernal equinox Aries was in the
+constellations of that name; it is now in Pisces, and will then pass
+into Aquarius. The pole star, i.e. the star towards which the Earth's
+axis points, is also shifting owing to precession; in about 2700 B.C.
+the Chinese observed [alpha] Draconis as the pole star (at present
+[alpha] Ursae minoris occupies this position and will do so until 3500);
+in 13600 Vega ([alpha] Lyrae) the brightest star in the Northern
+hemisphere, will be nearest.
+
+Precession is the result of the Sun and the Moon's attraction on the
+Earth not being a single force through its centre of gravity. If the
+Earth were a homogeneous sphere the attractions would act through the
+centre, and such forces would have no effect upon the rotation about the
+centre of gravity, but the Earth being spheroidal the equatorial band
+which stands up as it were beyond the surface of a sphere is more
+strongly attracted, with the result that the axis undergoes a tilting.
+The precession due to the Sun is termed the _solar precession_ and that
+due to the Moon the _lunar precession_; the joint effect (two-thirds of
+which is due to the Moon) is the _luni-solar_ precession. Solar
+precession is greatest at the solstices and zero at the equinoxes; the
+part of luni-solar precession due to the Moon varies with the position
+of the Moon in its orbit. The obliquity is unchanged by precession (see
+PRECESSION OF THE EQUINOXES).
+
+_Nutation._--In treating precession we have stated that the axis of the
+Earth traces a cone, and it follows that the pole describes a circle
+(approximately) on the celestial sphere, about the pole of the ecliptic.
+This is not quite true. Irregularities in the attracting forces which
+occasion precession also cause a slight oscillation backwards and
+forwards over the mean precessional path of the pole, the pole tracing a
+wavy line or nodding. Both the Sun and Moon contribute to this effect.
+Solar nutation depends upon the position of the Sun on the ecliptic; its
+period is therefore 1 year, and in extent it is only 1.2"; lunar
+nutation depends upon the position of the Moon's nodes; its period is
+therefore about 18.6 years, the time of revolution of the nodes, and its
+extent is 9.2". There is also given to the obliquity a small oscillation
+to and fro. Nutation is one of the great discoveries of James Bradley
+(1747).
+
+_Planetary Precession._--So far we have regarded the ecliptic as
+absolutely fixed, and treated precession as a real motion of the
+equator. The ecliptic (q.v.), however, is itself subject to a motion,
+due to the attractions of the planets on the Earth. This effect also
+displaces the equinoctial points. Its annual value is 0.13". The term
+General Precession in longitude is given to the displacement of the
+intersection of the equator with the apparent ecliptic on the latter.
+The standard value is 50.2453", which prevailed in 1850, and the value
+at 1850 + t, i.e. the constant of precession, is 50.2453" + 0.0002225"
+t. This value is also liable to a very small change. The nutation of the
+obliquity at time 1850 + t is given by the formula 23° 27' 32.0" - 0.47"
+t. Complete expressions for these functions are given in Newcomb's
+_Spherical Astronomy_ (1908), and in the _Nautical Almanac_.
+
+The variation of the _line of apsides_ is the name given to the motion
+of the major axis of the Earth's orbit along the ecliptic. It is due to
+the general influence of the planets, and the revolution is effected in
+21,000 years.
+
+The variation of the eccentricity denotes an oscillation of the form of
+the Earth's orbit between a circle and ellipse. This followed the
+mathematical researches of Lagrange and Leverrier. It was suggested by
+Sir John Herschel in 1830 that this variation might occasion great
+climatic changes, and James Croll developed the theory as affording a
+solution of the glacial periods in geology (q.v.).
+
+_Variation of Latitude._--Another secular motion of the Earth is due to
+the fact that the axis of rotation is not rigidly fixed within it, but
+its polar extremities wander in a circle of about 50 ft. diameter. This
+oscillation brings about a variability in terrestrial latitudes, hence
+the name. Euler showed mathematically that such an oscillation existed,
+and, making certain assumptions as to the rigidity of the Earth, deduced
+that its period was 305 days; S.C. Chandler, from 1890 onwards, deduced
+from observations of the stars a period of 428 days; and Simon Newcomb
+explained the deviation of these periods by pointing out that Euler's
+assumption of a perfectly rigid Earth is not in accordance with fact.
+For details of this intricate subject see the articles LATITUDE and
+EARTH, FIGURE OF THE.
+
+4. _Evolution and Age._--In its earliest history the mass now
+consolidated as the Earth and Moon was part of a vast nebulous
+aggregate, which in the course of time formed a central nucleus--our
+Sun--which shed its outer layers in such a manner as to form the solar
+system (see NEBULAR THEORY). The moon may have been formed from the
+Earth in a similar manner, but the theory of tidal friction suggests the
+elongation of the Earth along an equatorial axis to form a pear-shaped
+figure, and that in the course of time the protuberance shot off to form
+the Moon (see TIDE). The age of the Earth has been investigated from
+several directions, as have also associated questions related to
+climatic changes, internal temperature, orientation of the land and
+water (permanence of oceans and continents), &c. These problems are
+treated in the articles GEOLOGY and GEOGRAPHY.
+
+
+FOOTNOTE:
+
+  [1] Aristotle regarded the Earth as having an upper inhabited half
+    and a lower uninhabited one, and the air on the lower half as tending
+    to flow upwards through the Earth. The obstruction of this passage
+    brought about an accumulation of air within the Earth, and the
+    increased pressure may occasion oscillations of the surface, which
+    may be so intense as to cause earthquakes.
+
+
+
+
+EARTH, FIGURE OF THE. The determination of the figure of the earth is a
+problem of the highest importance in astronomy, inasmuch as the diameter
+of the earth is the unit to which all celestial distances must be
+referred.
+
+
+_Historical._
+
+Reasoning from the uniform level appearance of the horizon, the
+variations in altitude of the circumpolar stars as one travels towards
+the north or south, the disappearance of a ship standing out to sea, and
+perhaps other phenomena, the earliest astronomers regarded the earth as
+a sphere, and they endeavoured to ascertain its dimensions. Aristotle
+relates that the mathematicians had found the circumference to be
+400,000 stadia (about 46,000 miles). But Eratosthenes (c. 250 B.C.)
+appears to have been the first who entertained an accurate idea of the
+principles on which the determination of the figure of the earth really
+depends, and attempted to reduce them to practice. His results were very
+inaccurate, but his method is the same as that which is followed at the
+present day--depending, in fact, on the comparison of a line measured on
+the earth's surface with the corresponding arc of the heavens. He
+observed that at Syene in Upper Egypt, on the day of the summer
+solstice, the sun was exactly vertical, whilst at Alexandria at the same
+season of the year its zenith distance was 7° 12', or one-fiftieth of
+the circumference of a circle. He assumed that these places were on the
+same meridian; and, reckoning their distance apart as 5000 stadia, he
+inferred that the circumference of the earth was 250,000 stadia (about
+29,000 miles). A similar attempt was made by Posidonius, who adopted a
+method which differed from that of Eratosthenes only in using a star
+instead of the sun. He obtained 240,000 stadia (about 27,600 miles) for
+the circumference. Ptolemy in his _Geography_ assigns the length of the
+degree as 500 stadia.
+
+The Arabs also investigated the question of the earth's magnitude. The
+caliph Abdallah al Mamun (A.D. 814), having fixed on a spot in the
+plains of Mesopotamia, despatched one company of astronomers northwards
+and another southwards, measuring the journey by rods, until each found
+the altitude of the pole to have changed one degree. But the result of
+this measurement does not appear to have been very satisfactory. From
+this time the subject seems to have attracted no attention until about
+1500, when Jean Fernel (1497-1558), a Frenchman, measured a distance in
+the direction of the meridian near Paris by counting the number of
+revolutions of the wheel of a carriage. His astronomical observations
+were made with a triangle used as a quadrant, and his resulting length
+of a degree was very near the truth.
+
+Willebrord Snell[1] substituted a chain of triangles for actual linear
+measurement. He measured his base line on the frozen surface of the
+meadows near Leiden, and measured the angles of his triangles, which lay
+between Alkmaar and Bergen-op-Zoom, with a quadrant and semicircles. He
+took the precaution of comparing his standard with that of the French,
+so that his result was expressed in toises (the length of the toise is
+about 6.39 English ft.). The work was recomputed and reobserved by P.
+von Musschenbroek in 1729. In 1637 an Englishman, Richard Norwood,
+published a determination of the figure of the earth in a volume
+entitled _The Seaman's Practice, contayning a Fundamentall Probleme in
+Navigation experimentally verified, namely, touching the Compasse of the
+Earth and Sea and the quantity of a Degree in our English Measures_. He
+observed on the 11th of June 1633 the sun's meridian altitude in London
+as 62° 1', and on the 6th of June 1635, his meridian altitude in York as
+59° 33'. He measured the distance between these places partly with a
+chain and partly by pacing. By this means, through compensation of
+errors, he arrived at 367,176 ft. for the degree--a very fair result.
+
+The application of the telescope to angular instruments was the next
+important step. Jean Picard was the first who in 1669, with the
+telescope, using such precautions as the nature of the operation
+requires, measured an arc of meridian. He measured with wooden rods a
+base line of 5663 toises, and a second or base of verification of 3902
+toises; his triangulation extended from Malvoisine, near Paris, to
+Sourdon, near Amiens. The angles of the triangles were measured with a
+quadrant furnished with a telescope having cross-wires. The difference
+of latitude of the terminal stations was determined by observations made
+with a sector on a star in Cassiopeia, giving 1° 22' 55" for the
+amplitude. The terrestrial measurement gave 78,850 toises, whence he
+inferred for the length of the degree 57,060 toises.
+
+Hitherto geodetic observations had been confined to the determination of
+the magnitude of the earth considered as a sphere, but a discovery made
+by Jean Richer (d. 1696) turned the attention of mathematicians to its
+deviation from a spherical form. This astronomer, having been sent by
+the Academy of Sciences of Paris to the island of Cayenne, in South
+America, for the purpose of investigating the amount of astronomical
+refraction and other astronomical objects, observed that his clock,
+which had been regulated at Paris to beat seconds, lost about two
+minutes and a half daily at Cayenne, and that in order to bring it to
+measure mean solar time it was necessary to shorten the pendulum by more
+than a line (about {1/12}th of an in.). This fact, which was scarcely
+credited till it had been confirmed by the subsequent observations of
+Varin and Deshayes on the coasts of Africa and America, was first
+explained in the third book of Newton's _Principia_, who showed that it
+could only be referred to a diminution of gravity arising either from a
+protuberance of the equatorial parts of the earth and consequent
+increase of the distance from the centre, or from the counteracting
+effect of the centrifugal force. About the same time (1673) appeared
+Christian Huygens' _De Horologio Oscillatorio_, in which for the first
+time were found correct notions on the subject of centrifugal force. It
+does not, however, appear that they were applied to the theoretical
+investigation of the figure of the earth before the publication of
+Newton's _Principia_. In 1690 Huygens published his _De Causa
+Gravitatis_, which contains an investigation of the figure of the earth
+on the supposition that the attraction of every particle is towards the
+centre.
+
+Between 1684 and 1718 J. and D. Cassini, starting from Picard's base,
+carried a triangulation northwards from Paris to Dunkirk and southwards
+from Paris to Collioure. They measured a base of 7246 toises near
+Perpignan, and a somewhat shorter base near Dunkirk; and from the
+northern portion of the arc, which had an amplitude of 2° 12' 9",
+obtained for the length of a degree 56,960 toises; while from the
+southern portion, of which the amplitude was 6° 18' 57", they obtained
+57,097 toises. The immediate inference from this was that, the degree
+diminishing with increasing latitude, the earth must be a prolate
+spheroid. This conclusion was totally opposed to the theoretical
+investigations of Newton and Huygens, and accordingly the Academy of
+Sciences of Paris determined to apply a decisive test by the measurement
+of arcs at a great distance from each other--one in the neighbourhood of
+the equator, the other in a high latitude. Thus arose the celebrated
+expeditions of the French academicians. In May 1735 Louis Godin, Pierre
+Bouguer and Charles Marie de la Condamine, under the auspices of Louis
+XV., proceeded to Peru, where, assisted by two Spanish officers, after
+ten years of laborious exertion, they measured an arc of 3° 7', the
+northern end near the equator. The second party consisted of Pierre
+Louis Moreau de Maupertuis, Alexis Claude Clairault, Charles Étienne
+Louis Camus, Pierre Charles Lemonnier, and Reginaud Outhier, who reached
+the Gulf of Bothnia in July 1736; they were in some respects more
+fortunate than the first party, inasmuch as they completed the
+measurement of an arc near the polar circle of 57' amplitude and
+returned within sixteen months from the date of their departure.
+
+The measurement of Bouguer and De la Condamine was executed with great
+care, and on account of the locality, as well as the manner in which all
+the details were conducted, it has always been regarded as a most
+valuable determination. The southern limit was at Tarqui, the northern
+at Cotchesqui. A base of 6272 toises was measured in the vicinity of
+Quito, near the northern extremity of the arc, and a second base of 5260
+toises near the southern extremity. The mountainous nature of the
+country made the work very laborious, in some cases the difference of
+heights of two neighbouring stations exceeding 1 mile; and they had much
+trouble with their instruments, those with which they were to determine
+the latitudes proving untrustworthy. But they succeeded by simultaneous
+observations of the same star at the two extremities of the arc in
+obtaining very fair results. The whole length of the arc amounted to
+176,945 toises, while the difference of latitudes was 3° 7' 3". In
+consequence of a misunderstanding that arose between De la Condamine and
+Bouguer, their operations were conducted separately, and each wrote a
+full account of the expedition. Bouguer's book was published in 1749;
+that of De la Condamine in 1751. The toise used in this measure was
+afterwards regarded as the standard toise, and is always referred to as
+the _Toise of Peru_.
+
+The party of Maupertuis, though their work was quickly despatched, had
+also to contend with great difficulties. Not being able to make use of
+the small islands in the Gulf of Bothnia for the trigonometrical
+stations, they were forced to penetrate into the forests of Lapland,
+commencing operations at Torneå, a city situated on the mainland near
+the extremity of the gulf. From this, the southern extremity of their
+arc, they carried a chain of triangles northward to the mountain Kittis,
+which they selected as the northern terminus. The latitudes were
+determined by observations with a sector (made by George Graham) of the
+zenith distance of [alpha] and [delta] Draconis. The base line was
+measured on the frozen surface of the river Torneå about the middle of
+the arc; two parties measured it separately, and they differed by about
+4 in. The result of the whole was that the difference of latitudes of
+the terminal stations was 57' 29" .6, and the length of the arc 55,023
+toises. In this expedition, as well as in that to Peru, observations
+were made with a pendulum to determine the force of gravity; and these
+observations coincided with the geodetic results in proving that the
+earth was an oblate and not prolate spheroid.
+
+In 1740 was published in the Paris _Mémoires_ an account, by Cassini de
+Thury, of a remeasurement by himself and Nicolas Louis de Lacaille of
+the meridian of Paris. With a view to determine more accurately the
+variation of the degree along the meridian, they divided the distance
+from Dunkirk to Collioure into four partial arcs of about two degrees
+each, by observing the latitude at five stations. The results previously
+obtained by J. and D. Cassini were not confirmed, but, on the contrary,
+the length of the degree derived from these partial arcs showed on the
+whole an increase with an increasing latitude. Cassini and Lacaille also
+measured an arc of parallel across the mouth of the Rhone. The
+difference of time of the extremities was determined by the observers at
+either end noting the instant of a signal given by flashing gunpowder at
+a point near the middle of the arc.
+
+While at the Cape of Good Hope in 1752, engaged in various astronomical
+observations, Lacaille measured an arc of meridian of 1° 13' 17", which
+gave him for the length of the degree 57,037 toises--an unexpected
+result, which has led to the remeasurement of the arc by Sir Thomas
+Maclear (see GEODESY).
+
+Passing over the measurements made between Rome and Rimini and on the
+plains of Piedmont by the Jesuits Ruggiero Giuseppe Boscovich and
+Giovanni Battista Beccaria, and also the arc measured with deal rods in
+North America by Charles Mason and Jeremiah Dixon, we come to the
+commencement of the English triangulation. In 1783, in consequence of a
+representation from Cassini de Thury on the advantages that would accrue
+from the geodetic connexion of Paris and Greenwich, General William Roy
+was, with the king's approval, appointed by the Royal Society to conduct
+the operations on the part of England, Count Cassini, Méchain and
+Delambre being appointed on the French side. A precision previously
+unknown was attained by the use of Ramsden's theodolite, which was the
+first to make the spherical excess of triangles measurable. The wooden
+rods with which the first base was measured were replaced by glass rods,
+which were afterwards rejected for the steel chain of Ramsden. (For
+further details see _Account of the Trigonometrical Survey of England
+and Wales_.)
+
+Shortly after this, the National Convention of France, having agreed to
+remodel their system of weights and measures, chose for their unit of
+length the ten-millionth part of the meridian quadrant. In order to
+obtain this length precisely, the remeasurement of the French meridian
+was resolved on, and deputed to J.B.J. Delambre and Pierre François
+André Méchain. The details of this operation will be found in the _Base
+du système métrique décimale_. The arc was subsequently extended by Jean
+Baptiste Biot and Dominique François Jean Arago to the island of Iviza.
+Operations for the connexion of England with the continent of Europe
+were resumed in 1821 to 1823 by Henry Kater and Thomas Frederick Colby
+on the English side, and F.J.D. Arago and Claude Louis Mathieu on the
+French.
+
+The publication in 1838 of Friedrich Wilhelm Bessel's _Gradmessung in
+Ostpreussen_ marks an era in the science of geodesy. Here we find the
+method of least squares applied to the calculation of a network of
+triangles and the reduction of the observations generally. The
+systematic manner in which all the observations were taken with the view
+of securing final results of extreme accuracy is admirable. The
+triangulation, which was a small one, extended about a degree and a half
+along the shores of the Baltic in a N.N.E. direction. The angles were
+observed with theodolites of 12 and 15 in. diameter, and the latitudes
+determined by means of the transit instrument in the prime vertical--a
+method much used in Germany. (The base apparatus is described in the
+article GEODESY.)
+
+The principal triangulation of Great Britain and Ireland, which was
+commenced in 1783 under General Roy, for the more immediate purpose of
+connecting the observatories of Greenwich and Paris, had been gradually
+extended, under the successive direction of Colonel E. Williams, General
+W. Mudge, General T.F. Colby, Colonel L.A. Hall, and Colonel Sir Henry
+James; it was finished in 1851. The number of stations is about 250. At
+32 of these the latitudes were determined with Ramsden's and Airy's
+zenith sectors. The theodolites used for this work were, in addition to
+the two great theodolites of Ramsden which were used by General Roy and
+Captain Kater, a smaller theodolite of 18 in. diameter by the same
+mechanician, and another of 24 in. diameter by Messrs Troughton and
+Simms. Observations for determination of absolute azimuth were made with
+those instruments at a large number of stations; the stars [alpha],
+[delta], and [lambda] Ursae Minoris and 51 Cephei being those observed
+always at the greatest azimuths. At six of these stations the probable
+error of the result is under 0.4", at twelve under 0.5", at thirty-four
+under 0.7": so that the absolute azimuth of the whole network is
+determined with extreme accuracy. Of the seven base lines which have
+been measured, five were by means of steel chains and two with Colby's
+compensation bars (see GEODESY). The triangulation was computed by least
+squares. The total number of equations of condition for the
+triangulation is 920; if therefore the whole had been reduced in one
+mass, as it should have been, the solution of an equation of 920 unknown
+quantities would have occurred as a part of the work. To avoid this an
+approximation was resorted to; the triangulation was divided into
+twenty-one parts or figures; four of these, not adjacent, were first
+adjusted by the method explained, and the corrections thus determined in
+these figures carried into the equations of condition of the adjacent
+figures. The average number of equations in a figure is 44; the largest
+equation is one of 77 unknown quantities. The vertical limb of Airy's
+zenith sector is read by four microscopes, and in the complete
+observation of a star there are 10 micrometer readings and 12 level
+readings. The instrument is portable; and a complete determination of
+latitude, affected with the mean of the declination errors of two stars,
+is effected by two micrometer readings and four level readings. The
+observation consists in measuring with the telescope micrometer the
+difference of zenith distances of two stars which cross the meridian,
+one to the north and the other to the south of the observer at zenith
+distances which differ by not much more than 10' or 15', the interval of
+the times of transit being not less than one nor more than twenty
+minutes. The advantages are that, with simplicity in the construction of
+the instrument and facility in the manipulation, refraction is
+eliminated (or nearly so, as the stars are generally selected within 25°
+of the zenith), and there is no large divided circle. The telescope,
+which is counterpoised on one side of the vertical axis, has a small
+circle for finding, and there is also a small horizontal circle. This
+instrument is universally used in American geodesy.
+
+  The principal work containing the methods and results of these
+  operations was published in 1858 with the title "Ordnance
+  Trigonometrical Survey of Great Britain and Ireland. Account of the
+  observations and calculations of the principal triangulation and of
+  the figure, dimensions and mean specific gravity of the earth as
+  derived therefrom. Drawn up by Captain Alexander Ross Clarke, R.E.,
+  F.R.A.S., under the direction of Lieut.-Colonel H. James, R.E.,
+  F.R.S., M.R.I.A., &c." A supplement appeared in 1862: "Extension of
+  the Triangulation of the Ordnance Survey into France and Belgium, with
+  the measurement of an arc of parallel in 52° N. from Valentia in
+  Ireland to Mount Kemmel in Belgium. Published by ... Col. Sir Henry
+  James."
+
+Extensive operations for surveying India and determining the figure of
+the earth were commenced in 1800. Colonel W. Lambton started the great
+meridian arc at Punnae in latitude 8° 9', and, following generally the
+methods of the English survey, he carried his triangulation as far north
+as 20° 30'. The work was continued by Sir George (then Captain) Everest,
+who carried it to the latitude of 29° 30'. Two admirable volumes by Sir
+George Everest, published in 1830 and in 1847, give the details of this
+undertaking. The survey was afterwards prosecuted by Colonel T.T.
+Walker, R.E., who made valuable contributions to geodesy. The working
+out of the Indian chains of triangle by the method of least squares
+presents peculiar difficulties, but, enormous in extent as the work was,
+it has been thoroughly carried out. The ten base lines on which the
+survey depends were measured with Colby's compensation bars.
+
+  The survey is detailed in eighteen volumes, published at Dehra Dun,
+  and entitled _Account of the Operations of the Great Trigonometrical
+  Survey of India_. Of these the first nine were published under the
+  direction of Colonel Walker; and the remainder by Colonels Strahan and
+  St G.C. Gore, Major S.G. Burrard and others. Vol. i., 1870, treats of
+  the base lines; vol. ii., 1879, history and general descriptions of
+  the principal triangulation and of its reduction; vol. v., 1879,
+  pendulum operations (Captains T.P. Basevi and W.T. Heaviside); vols.
+  xi., 1890, and xviii., 1906, latitudes; vols. ix., 1883, x., 1887,
+  xv., 1893, longitudes; vol. xvii., 1901, the Indo-European
+  longitude-arcs from Karachi to Greenwich. The other volumes contain
+  the triangulations.
+
+In 1860 Friedrich Georg Wilhelm Struve published his _Arc du méridien de
+25° 20' entre le Danube et la Mer Glaciale mesuré depuis 1816 jusqu'en
+1855_. The latitudes of the thirteen astronomical stations of this arc
+were determined partly with vertical circles and partly by means of the
+transit instrument in the prime vertical. The triangulation, a great
+part of which, however, is a simple chain of triangles, is reduced by
+the method of least squares, and the probable errors of the resulting
+distances of parallels is given; the probable error of the whole arc in
+length is ± 6.2 toises. Ten base lines were measured. The sum of the
+lengths of the ten measured bases is 29,863 toises, so that the average
+length of a base line is 19,100 ft. The azimuths were observed at
+fourteen stations. In high latitudes the determination of the meridian
+is a matter of great difficulty; nevertheless the azimuths at all the
+northern stations were successfully determined,--the probable error of
+the result at Fuglenaes being ± 0".53.
+
+Before proceeding with the modern developments of geodetic measurements
+and their application to the figure of the earth, we must discuss the
+"mechanical theory," which is indispensable for a full understanding of
+the subject.
+
+
+_Mechanical Theory._
+
+Newton, by applying his theory of gravitation, combined with the
+so-called centrifugal force, to the earth, and assuming that an oblate
+ellipsoid of rotation is a form of equilibrium for a homogeneous fluid
+rotating with uniform angular velocity, obtained the ratio of the axes
+229:230, and the law of variation of gravity on the surface. A few years
+later Huygens published an investigation of the figure of the earth,
+supposing the attraction of every particle to be towards the centre of
+the earth, obtaining as a result that the proportion of the axes should
+be 578 : 579. In 1740 Colin Maclaurin, in his _De causa physica fluxus
+et refluxus maris_, demonstrated that the oblate ellipsoid of revolution
+is a figure which satisfies the conditions of equilibrium in the case of
+a revolving homogeneous fluid mass, whose particles attract one another
+according to the law of the inverse square of the distance; he gave the
+equation connecting the ellipticity with the proportion of the
+centrifugal force at the equator to gravity, and determined the
+attraction on a particle situated anywhere on the surface of such a
+body. In 1743 Clairault published his _Théorie de la figure de la
+terre_, which contains a remarkable theorem ("Clairault's Theorem"),
+establishing a relation between the ellipticity of the earth and the
+variation of gravity from the equator to the poles. Assuming that the
+earth is composed of concentric ellipsoidal strata having a common axis
+of rotation, each stratum homogeneous in itself, but the ellipticities
+and densities of the successive strata varying according to any law, and
+that the superficial stratum has the same form as if it were fluid, he
+proved that
+
+  g'- g       5
+  ----- + e = -- m,
+    g         2
+
+where g, g' are the amounts of gravity at the equator and at the pole
+respectively, e the ellipticity of the meridian (or "flattening"), and m
+the ratio of the centrifugal force at the equator to g. He also proved
+that the increase of gravity in proceeding from the equator to the poles
+is as the square of the sine of the latitude. This, taken with the
+former theorem, gives the means of determining the earth's ellipticity
+from observation of the relative force of gravity at any two places.
+P.S. Laplace, who devoted much attention to the subject, remarks on
+Clairault's work that "the importance of all his results and the
+elegance with which they are presented place this work amongst the most
+beautiful of mathematical productions" (Isaac Todhunter's _History of
+the Mathematical Theories of Attraction and the Figure of the Earth_,
+vol. i. p. 229).
+
+The problem of the figure of the earth treated as a question of
+mechanics or hydrostatics is one of great difficulty, and it would be
+quite impracticable but for the circumstance that the surface differs
+but little from a sphere. In order to express the forces at any point of
+the body arising from the attraction of its particles, the form of the
+surface is required, but this form is the very one which it is the
+object of the investigation to discover; hence the complexity of the
+subject, and even with all the present resources of mathematicians only
+a partial and imperfect solution can be obtained.
+
+  We may here briefly indicate the line of reasoning by which some of
+  the most important results may be obtained. If X, Y, Z be the
+  components parallel to three rectangular axes of the forces acting on
+  a particle of a fluid mass at the point x, y, z, then, p being the
+  pressure there, and [rho] the density,
+
+    dp = [rho](Xdx + Ydy + Zdz);
+
+  and for equilibrium the necessary conditions are, that [rho](Xdx + Ydy
+  + Zdz) be a complete differential, and at the free surface Xdx + Ydy +
+  Zdz = 0. This equation implies that the resultant of the forces is
+  normal to the surface at every point, and in a homogeneous fluid it is
+  obviously the differential equation of all surfaces of equal pressure.
+  If the fluid be heterogeneous then it is to be remarked that for
+  forces of attraction according to the ordinary law of gravitation, if
+  X, Y, Z be the components of the attraction of a mass whose potential
+  is V, then
+
+                       dV     dV     dV
+    Xdx + Ydy + Zdz =  --dx + --dy + --dz,
+                       dx     dy     dz
+
+  which is a complete differential. And in the case of a fluid rotating
+  with uniform velocity, in which the so-called centrifugal force enters
+  as a force acting on each particle proportional to its distance from
+  the axis of rotation, the corresponding part of Xdx + Ydy + Zdz is
+  obviously a complete differential. Therefore for the forces with which
+  we are now concerned Xdx + Ydy + Zdz = dU, where U is some function of
+  x, y, z, and it is necessary for equilibrium that dp = [rho]dU be a
+  complete differential; that is, [rho] must be a function of U or a
+  function of p, and so also p a function of U. So that dU = 0 is the
+  differential equation of surfaces of equal pressure and density.
+
+  We may now show that a homogeneous fluid mass in the form of an oblate
+  ellipsoid of revolution having a uniform velocity of rotation can be
+  in equilibrium. It may be proved that the attraction of the ellipsoid
+  x² + y² + z²(1 + [epsilon]²) = c²(1 + [epsilon]²); upon a particle P
+  of its mass at x, y, z has for components
+
+    X = -Ax, Y = -Ay, Z = -Cz,
+
+  where
+
+                     /1 + [epsilon]²                        1     \
+    A = 2[pi]k²[rho]( ------------- tan^(-1) [epsilon] - --------  ),
+                     \  [epsilon]³                      [epsilon]²/
+
+                     /1 + [epsilon]²   1 + [epsilon]²                  \
+    C = 4[pi]k²[rho]( -------------- - ------------- tan^(-1) [epsilon] ),
+                     \  [epsilon]²      [epsilon]³                     /
+
+  and k² the constant of attraction. Besides the attraction of the mass
+  of the ellipsoid, the centrifugal force at P has for components +
+  x[omega]², + y[omega]², 0; then the condition of fluid equilibrium is
+
+    (A - [omega]²)xdx + (A - [omega]²)ydy + Czdz = 0,
+
+  which by integration gives
+
+    (A - [omega]²)(x² + y²) + Cz² = constant.
+
+  This is the equation of an ellipsoid of rotation, and therefore the
+  equilibrium is possible. The equation coincides with that of the
+  surface of the fluid mass if we make
+
+    A - [omega]² = C/(1 + [epsilon]²),
+
+  which gives
+
+      [omega]²     3 + [epsilon]²                           3
+    ------------ = -------------- tan^(-1) [epsilon] - ---------- .
+    2[pi]k²[rho]     [epsilon]³                        [epsilon]²
+
+  In the case of the earth, which is nearly spherical, we obtain by
+  expanding the expression for [omega]² in powers of [epsilon]²,
+  rejecting the higher powers, and remarking that the ellipticity e =
+  ½[epsilon]²,
+
+    [omega]²/2[pi]k²[rho] = 4[epsilon]²/15 = 8e/15.
+
+  Now if m be the ratio of the centrifugal force to the intensity of
+  gravity at the equator, and a = c(1 + e), then
+
+    m = a[omega]²,/(4/3)[pi]k²[rho]a, :. [omega]²/2[pi]k²[rho] = (2/3)m.
+
+  In the case of the earth it is a matter of observation that m =
+  1/289, hence the ellipticity
+
+    e = 5m/4 = 1/231,
+
+  so that the ratio of the axes on the supposition of a homogeneous
+  fluid earth is 230:231, as stated by Newton.
+
+  Now, to come to the case of a heterogeneous fluid, we shall assume
+  that its surfaces of equal density are spheroids, concentric and
+  having a common axis of rotation, and that the ellipticity of these
+  surfaces varies from the centre to the outer surface, the density also
+  varying. In other words, the body is composed of homogeneous
+  spheroidal shells of variable density and ellipticity. On this
+  supposition we shall express the attraction of the mass upon a
+  particle in its interior, and then, taking into account the
+  centrifugal force, form the equation expressing the condition of fluid
+  equilibrium. The attraction of the homogeneous spheroid x² + y² + z²(1
+  + 2e) = c²(1 + 2e), where e is the ellipticity (of which the square is
+  neglected), on an internal particle, whose co-ordinates are x = f, y =
+  0, z = h, has for its x and z components
+
+    X' = -(4/3)[pi]k²[rho]f(1 - (2/5)e),
+    Z' = -(4/3)[pi]k²[rho]h(1 + (4/5)e),
+
+  the Y component being of course zero. Hence we infer that the
+  attraction of a shell whose inner surface has an ellipticity e, and
+  its outer surface an ellipticity e + de, the density being [rho], is
+  expressed by
+
+    dX' = (4/3)·(2/5)[pi]k²[rho]f de, dZ' = -(4/3)·(4/5)[pi]k²[rho]h de.
+
+  To apply this to our heterogeneous spheroid; if we put c1 for the
+  semiaxis of that surface of equal density on which is situated the
+  attracted point P, and c0 for the semiaxis of the outer surface, the
+  attraction of that portion of the body which is exterior to P, namely,
+  of all the shells which enclose P, has for components
+                    _                               _
+          8        /c0     de           16         /c0     de
+    X0 = --[pi]k²f | [rho] --dc, Z0 = - -- [pi]k²h | [rho] --dc,
+         15       _/c1     dc           15        _/c1     dc
+
+  both e and [rho] being functions of c. Again the attraction of a
+  homogeneous spheroid of density [rho] on an _external_ point f, h has
+  the components
+
+    X" = -(4/3)[pi]k²[rho]fr^(-3) {c³(1 + 2e) - [lambda]ec^5},
+    Z" = -(4/3)[pi]k²[rho]hr^(-3) {c³(1 + 2e) - [lambda]'ec^5},
+
+  where [lambda] = (3/5)(4h² - f²)/r^4,
+        [lambda]' = (3/5)(2h² - 3f²)/r^4, and r² = f² + h².
+
+  Now e being considered a function of c, we can at once express the
+  attraction of a shell (density [rho]) contained between the surface
+  defined by c + dc, e + de and that defined by c, e upon an external
+  point; the differentials with respect to c, viz. dX" dZ", must then
+  be integrated with [rho] under the integral sign as being a function
+  of c. The integration will extend from c = 0 to c = c1. Thus the
+  components of the attraction of the heterogeneous spheroid upon a
+  particle within its mass, whose co-ordinates are f, 0, h, are
+                      _     _
+          4          | 1   /c1
+    X = - -- [pi]k²f | --  | [rho] d{c³(1 + 2e)}
+          3          |_r³ _/0
+
+                  _                    _        _
+        [lambda] /c1               2  /c1        |
+      - -------- | [rho] d(ec^5) - -- | [rho] de |,
+           r³   _/0                5 _/0        _|
+                      _     _
+          4          | 1   /c1
+    Z = - -- [pi]k²h | --  | [rho] d{c³(1 + 2e)}
+          3          |_r³ _/0
+
+                  _                    _        _
+        [lambda]'/c1               4  /c1        |
+      - -------- | [rho] d(ec^5) + -- | [rho] de |.
+           r³   _/0                5 _/0        _|
+
+  We take into account the rotation of the earth by adding the
+  centrifugal force f[omega]² = F to X. Now, the surface of constant
+  density upon which the point f, 0, h is situated gives (1 - 2e) fdf +
+  hdh = 0; and the condition of equilibrium is that (X + F)df + Zdh = 0.
+  Therefore,
+
+    (X + F)h = Zf(1 - 2e),
+
+  which, neglecting small quantities of the order e² and putting
+  [omega]²t² = 4[pi]²k², gives
+        _                            _                   _
+    2e /c1                     6    /c1              6  /c0         3[pi]
+    -- | [rho]d{c³(1 + 2e)} - ----  | [rho]d(ec^5) - -- | [rho]de = -----.
+    r³_/0                     5r^5 _/0               5 _/c1           t²
+
+  Here we must now put c for c1, c for r; and 1 + 2e under the first
+  integral sign may be replaced by unity, since small quantities of the
+  second order are neglected. Two differentiations lead us to the
+  following very important differential equation (Clairault):
+
+    d²e      2[rho]c²      de    /    2[rho]c      6 \
+    --- + -------------- · -- + ( -------------- - -- ) e = 0.
+    dc²   [int][rho]c²dc   dc    \[int][rho]c²dc   c²/
+
+  When [rho] is expressed in terms of c, this equation can be
+  integrated. We infer then that a rotating spheroid of very small
+  ellipticity, composed of fluid homogeneous strata such as we have
+  specified, will be in equilibrium; and when the law of the density is
+  expressed, the law of the corresponding ellipticities will follow.
+
+  If we put M for the mass of the spheroid, then
+               _
+        4[pi] /c                             c³   4[pi]²
+    M = ----- | [rho]d{c³(1 + 2e)}; and m = --- · -----,
+          3  _/0                             M      t²
+
+  and putting c = c0 in the equation expressing the condition of
+  equilibrium, we find
+                             _
+                4        6  /c
+    M(2e - m) = -- [pi]·--- | [rho]d(ec^5).
+                3       5c²_/0
+
+  Making these substitutions in the expressions for the forces at the
+  surface, and putting r/c = 1 + e - e(h/c)², we get
+                       _                             _
+                  Mk² |         3       /5      \  h² | f
+    G cos [phi] = --- | 1 - e - -- m + ( - m - 2e) -- | --
+                  ac  |_        2       \2      /  c²_| c
+                       _                             _
+                  Mk² |         3       /5      \  h² | h
+    G sin [phi] = --- | 1 + e - -- m + ( - m - 2e) -- | --.
+                  ac  |_        2       \2      /  c²_| c
+
+  Here G is gravity in the latitude [phi], and a the radius of the
+  equator. Since
+
+    sec [phi] = (c/f){1 + e + (eh²/c²)},
+             _                                 _
+        Mk² |     3       /5      \             |
+    G = --- | 1 - -- m + ( -- m - e) sin² [phi] |,
+        ac  |_    2       \2      /            _|
+
+  an expression which contains the theorems we have referred to as
+  discovered by Clairault.
+
+  The theory of the figure of the earth as a rotating ellipsoid has been
+  especially investigated by Laplace in his _Mécanique celeste_. The
+  principal English works are:--Sir George Airy, _Mathematical Tracts_,
+  a lucid treatment without the use of Laplace's coefficients;
+  Archdeacon Pratt's _Attractions and Figure of the Earth_; and
+  O'Brien's _Mathematical Tracts_; in the last two Laplace's
+  coefficients are used.
+
+In 1845 Sir G.G. Stokes (_Camb. Trans._ viii.; see also _Camb. Dub.
+Math. Journ._, 1849, iv.) proved that if the external form of the
+sea--imagined to percolate the land by canals--be a spheroid with small
+ellipticity, then the law of gravity is that which we have shown above;
+his proof required no assumption as to the ellipticity of the internal
+strata, or as to the past or present fluidity of the earth. This
+investigation admits of being regarded conversely, viz. as determining
+the elliptical form of the earth from measurements of gravity; if G, the
+observed value of gravity in latitude [phi], be expressed in the form G
+= g(1 + ß sin² [phi]), where g is the value at the equator and ß a
+coefficient. In this investigation, the square and higher powers of the
+ellipticity are neglected; the solution was completed by F.R. Helmert
+with regard to the square of the ellipticity, who showed that a term
+with sin² 2[phi] appeared (see Helmert, _Geodäsie_, ii. 83). For the
+coefficient of this term, the gravity measurements give a small but not
+sufficiently certain value; we therefore assume a value which agrees
+best with the hypothesis of the fluid state of the entire earth; this
+assumption is well supported, since even at a depth of only 50 km. the
+pressure of the superincumbent crust is so great that rocks become
+plastic, and behave approximately as fluids, and consequently the crust
+of the earth floats, to some extent, on the interior (even though this
+may not be fluid in the usual sense of the word). This is the geological
+theory of "Isostasis" (cf. GEOLOGY); it agrees with the results of
+measurements of gravity (_vide infra_), and was brought forward in the
+middle of the 19th century by J.H. Pratt, who deduced it from
+observations made in India.
+
+The sin² 2[phi] term in the expression for G, and the corresponding
+deviation of the meridian from an ellipse, have been analytically
+established by Sir G.H. Darwin and E. Wiechert; earlier and less
+complete investigations were made by Sir G.B. Airy and O. Callandreau.
+In consequence of the sin² 2[phi] term, two parameters of the level
+surfaces in the interior of the earth are to be determined; for this
+purpose, Darwin develops two differential equations in the place of the
+one by Clairault. By assuming Roche's law for the variation of the
+density in the interior of the Earth, viz. [rho] = [rho]1 - k(c/c1)², k
+being a coefficient, it is shown that in latitude 45°, the meridian is
+depressed about 3¼ metres from the ellipse, and the coefficient of the
+term sin² [phi] cos² [phi] (= ¼ sin² 2[phi]) is -0.0000295. According to
+Wiechert the earth is composed of a kernel and a shell, the kernel being
+composed of material, chiefly metallic iron, of density near 8.2, and
+the shell, about 900 miles thick, of silicates, &c., of density about
+3.2. On this assumption the depression in latitude 45° is 2¾ metres, and
+the coefficient of sin² [phi] cos² [phi] is, in round numbers,
+-0.0000280.[2] To this additional term in the formula for G, there
+corresponds an extension of Clairault's formula for the calculation of
+the flattening from ß with terms of the higher orders; this was first
+accomplished by Helmert.
+
+For a long time the assumption of an ellipsoid with three unequal axes
+has been held possible for the figure of the earth, in consequence of an
+important theorem due to K.G. Jacobi, who proved that for a homogeneous
+fluid in rotation a spheroid is not the only form of equilibrium; an
+ellipsoid rotating round its least axis may with certain proportions of
+the axes and a certain time of revolution be a form of equilibrium.[3]
+It has been objected to the figure of three unequal axes that it does
+not satisfy, in the proportions of the axes, the conditions brought out
+in Jacobi's theorem (c: a < 1/[root]2). Admitting this, it has to be
+noted, on the other hand, that Jacobi's theorem contemplates a
+homogeneous fluid, and this is certainly far from the actual condition
+of our globe; indeed the irregular distribution of continents and oceans
+suggests the possibility of a sensible divergence from a perfect surface
+of revolution. We may, however, assume the ellipsoid with three unequal
+axes to be an interpolation form. More plausible forms are little
+adapted for computation.[4] Consequently we now generally take the
+ellipsoid of rotation as a basis, especially so because measurements of
+gravity have shown that the deviation from it is but trifling.
+
+
+_Local Attraction._
+
+In speaking of the figure of the earth, we mean the surface of the sea
+imagined to percolate the continents by canals. That this surface
+should turn out, after precise measurements, to be exactly an ellipsoid
+of revolution is _a priori_ improbable. Although it may be highly
+probable that originally the earth was a fluid mass, yet in the cooling
+whereby the present crust has resulted, the actual solid surface has
+been left most irregular in form. It is clear that these irregularities
+of the visible surface must be accompanied by irregularities in the
+mathematical figure of the earth, and when we consider the general
+surface of our globe, its irregular distribution of mountain masses,
+continents, with oceans and islands, we are prepared to admit that the
+earth may not be precisely any surface of revolution. Nevertheless,
+there must exist some spheroid which agrees very closely with the
+mathematical figure of the earth, and has the same axis of rotation. We
+must conceive this figure as exhibiting slight departures from the
+spheroid, the two surfaces cutting one another in various lines; thus a
+point of the surface is defined by its latitude, longitude, and its
+height above the "spheroid of reference." Calling this height N, then of
+the actual magnitude of this quantity we can generally have no
+information, it only obtrudes itself on our notice by its variations. In
+the vicinity of mountains it may change sign in the space of a few
+miles; N being regarded as a function of the latitude and longitude, if
+its differential coefficient with respect to the former be zero at a
+certain point, the normals to the two surfaces then will lie in the
+prime vertical; if the differential coefficient of N with respect to the
+longitude be zero, the two normals will lie in the meridian; if both
+coefficients are zero, the normals will coincide. The comparisons of
+terrestrial measurements with the corresponding astronomical
+observations have always been accompanied with discrepancies. Suppose A
+and B to be two trigonometrical stations, and that at A there is a
+disturbing force drawing the vertical through an angle [delta], then it
+is evident that the apparent zenith of A will be really that of some
+other place A', whose distance from A is r[delta], when r is the earth's
+radius; and similarly if there be a disturbance at B of the amount
+[delta]', the apparent zenith of B will be really that of some other
+place B', whose distance from B is r[delta]'. Hence we have the
+discrepancy that, while the geodetic measurements deal with the points A
+and B, the astronomical observations belong to the points A', B'. Should
+[delta], [delta]' be equal and parallel, the displacements AA', BB' will
+be equal and parallel, and no discrepancy will appear. The
+non-recognition of this circumstance often led to much perplexity in the
+early history of geodesy. Suppose that, through the unknown variations
+of N, the probable error of an observed latitude (that is, the angle
+between the normal to the mathematical surface of the earth at the given
+point and that of the corresponding point on the spheroid of reference)
+be [epsilon], then if we compare two arcs of a degree each in mean
+latitudes, and near each other, say about five degrees of latitude
+apart, the probable error of the resulting value of the ellipticity will
+be approximately ± 1/500[epsilon], [epsilon] being expressed in
+seconds, so that if [epsilon] be so great as 2" the probable error of
+the resulting ellipticity will be greater than the ellipticity itself.
+
+It is necessary at times to calculate the attraction of a mountain, and
+the consequent disturbance of the astronomical zenith, at any point
+within its influence. The deflection of the plumb-line, caused by a
+local attraction whose amount is k²A[delta], is measured by the ratio of
+k²A[delta] to the force of gravity at the station. Expressed in seconds,
+the deflection [Lambda] is
+
+  [Lambda] = 12".447A[delta]/[rho],
+
+where [rho] is the mean density of the earth, [delta] that of the
+attracting mass, and A = [f]s^(-3)xdv, in which dv is a volume element
+of the attracting mass within the distance s from the point of
+deflection, and x the projection of s on the horizontal plane through
+this point, the linear unit in expressing A being a mile. Suppose, for
+instance, a table-land whose form is a rectangle of 12 miles by 8 miles,
+having a height of 500 ft. and density half that of the earth; let the
+observer be 2 miles distant from the middle point of the longer side.
+The deflection then is 1".472; but at 1 mile it increases to 2".20.
+
+At sixteen astronomical stations in the English survey the disturbance
+of latitude due to the form of the ground has been computed, and the
+following will give an idea of the results. At six stations the
+deflection is under 2", at six others it is between 2" and 4", and at
+four stations it exceeds 4". There is one very exceptional station on
+the north coast of Banffshire, near the village of Portsoy, at which the
+deflection amounts to 10", so that if that village were placed on a map
+in a position to correspond with its astronomical latitude, it would be
+1000 ft. out of position! There is the sea to the north and an
+undulating country to the south, which, however, to a spectator at the
+station does not suggest any great disturbance of gravity. A somewhat
+rough estimate of the local attraction from external causes gives a
+maximum limit of 5", therefore we have 5" which must arise from
+unequal density in the underlying strata in the surrounding country. In
+order to throw light on this remarkable phenomenon, the latitudes of a
+number of stations between Nairn on the west, Fraserburgh on the east,
+and the Grampians on the south, were observed, and the local deflections
+determined. It is somewhat singular that the deflections diminish in all
+directions, not _very_ regularly certainly, and most slowly in a
+south-west direction, finally disappearing, and leaving the maximum at
+the original station at Portsoy.
+
+The method employed by Dr C. Hutton for computing the attraction of
+masses of ground is so simple and effectual that it can hardly be
+improved on. Let a horizontal plane pass through the given station; let
+r, [theta] be the polar co-ordinates of any point in this plane, and r,
+[theta], z, the co-ordinates of a particle of the attracting mass; and
+let it be required to find the attraction of a portion of the mass
+contained between the horizontal planes z = 0, z = h, the cylindrical
+surfaces r = r1, r = r2, and the vertical planes [theta] = [theta]1,
+[theta] = [theta]2. The component of the attraction at the station or
+origin along the line [theta] = 0 is
+             _    _          _
+            /r2  /[theta]2  /h  r²cos [theta]
+  k²[delta] |    |          |   ------------- dr d[theta] dz
+           _/r1 _/[theta]1 _/0  (r²+z²)^(3/2)
+
+    = k²[delta]h(sin[theta]2 - sin[theta]1) log{r2 + (r2² + h²)^(½)/r1 + (r1² + h²)^(½)}.
+
+By taking r2 - r1, sufficiently small, and supposing h also small
+compared with r1 + r2 (as it usually is), the attraction is
+
+  k²[delta](r2 - r1)(sin [theta]2 - sin [theta]1)h/r,
+
+where r= ½(r1 + r2). This form suggests the following procedure. Draw on
+the contoured map a series of equidistant circles, concentric with the
+station, intersected by radial lines so disposed that the sines of their
+azimuths are in arithmetical progression. Then, having estimated from
+the map the mean heights of the various compartments, the calculation is
+obvious.
+
+In mountainous countries, as near the Alps and in the Caucasus,
+deflections have been observed to the amount of as much as 30", while
+in the Himalayas deflections amounting to 60" were observed. On the
+other hand, deflections have been observed in flat countries, such as
+that noted by Professor K.G. Schweizer, who has shown that, at certain
+stations in the vicinity of Moscow, within a distance of 16 miles the
+plumb-line varies 16" in such a manner as to indicate a vast deficiency
+of matter in the underlying strata; deflections of 10" were observed in
+the level regions of north Germany.
+
+Since the attraction of a mountain mass is expressed as a numerical
+multiple of [delta] : [rho] the ratio of the density of the mountain to
+that of the earth, if we have any independent means of ascertaining the
+amount of the deflection, we have at once the ratio [rho]:[delta], and
+thus we obtain the mean density of the earth, as, for instance, at
+Schiehallion, and afterwards at Arthur's Seat. Experiments of this kind
+for determining the mean density of the earth have been made in greater
+numbers; but they are not free from objection (see GRAVITATION).
+
+Let us now consider the perturbation attending a spherical subterranean
+mass. A compact mass of great density at a small distance under the
+surface of the earth will produce an elevation of the mathematical
+surface which is expressed by the formula
+
+  y = aµ((1 - 2u cos [theta] + u²)^(-½) - 1),
+
+where a is the radius of the (spherical) earth, a(1 - u) the distance
+of the disturbing mass below the surface, µ the ratio of the disturbing
+mass to the mass of the earth, and a[theta] the distance of any point on
+the surface from that point, say Q, which is vertically over the
+disturbing mass. The maximum value of y is at Q, where it is y = aµu(1
+-u). The deflection at the distance a[theta] is [Lambda] = µu
+sin[theta](1 - 2u cos[theta] + u²)^(-3/2), or since [theta] is small,
+putting h + u = 1, we have [Lambda] = µ[theta](h² + [theta]²)^(-3/2).
+The maximum deflection takes place at a point whose distance from Q is
+to the depth of the mass as 1:[root]2, and its amount is 2µ/3
+[root](3h²). If, for instance, the disturbing mass were a sphere a mile
+in diameter, the excess of its density above that of the surrounding
+country being equal to half the density of the earth, and the depth of
+its centre half a mile, the greatest deflection would be 5", and the
+greatest value of y only two inches. Thus a large disturbance of gravity
+may arise from an irregularity in the mathematical surface whose actual
+magnitude, as regards height at least, is extremely small.
+
+The effect of the disturbing mass µ on the vibrations of a pendulum
+would be a maximum at Q; if v be the number of seconds of time gained
+per diem by the pendulum at Q, and [sigma] the number of seconds of
+angle in the maximum deflection, then it may be shown that v/[sigma] =
+[pi][root]3/10.
+
+The great Indian survey, and the attendant measurements of the degree of
+latitude, gave occasion to elaborate investigations of the deflection of
+the plumb-line in the neighbourhood of the high plateaus and mountain
+chains of Central Asia. Archdeacon Pratt (_Phil. Trans._, 1855 and
+1857), in instituting these investigations, took into consideration the
+influence of the apparent diminution of the mass of the earth's crust
+occasioned by the neighbouring ocean-basins; he concluded that the
+accumulated masses of mountain chains, &c., corresponded to subterranean
+mass diminutions, so that over any level surface in a fixed depth
+(perhaps 100 miles or more) the masses of prisms of equal section are
+equal. This is supported by the gravity measurements at Moré in the
+Himalayas at a height of 4696 metres, which showed no deflection due to
+the mountain chain (_Phil. Trans._, 1871); more recently, H.A. Faye
+(_Compt. rend._, 1880) arrived at the same conclusion for the entire
+continent.
+
+This compensation, however, must only be regarded as a general
+principle; in certain cases, the compensating masses show marked
+horizontal displacements. Further investigations, especially of gravity
+measurements, will undoubtedly establish other important facts. Colonel
+S.G. Burrard has recently recalculated, with the aid of more exact data,
+certain Indian deviations of the plumb-line, and has established that in
+the region south of the Himalayas (lat. 24°) there is a subterranean
+perturbing mass. The extent of the compensation of the high mountain
+chains is difficult to recognize from the latitude observations, since
+the same effect may result from different causes; on the other hand,
+observations of geographical longitude have established a strong
+compensation.[5]
+
+
+_Meridian Arcs._
+
+The astronomical stations for the measurement of the degree of latitude
+will generally lie not exactly on the same meridian; and it is therefore
+necessary to calculate the arcs of meridian M which lie between the
+latitude of neighbouring stations. If S be the geodetic line calculated
+from the triangulation with the astronomically determined azimuths
+[alpha]1 and [alpha]2, then
+                             _                                _
+            cos [alpha]     |      1    S²                     |
+  M = S ------------------- | 1 + -- -------- sin² [alpha] ... |,
+        cos ½[Delta][alpha] |_    12 [alpha]²                 _|
+
+in which 2[alpha] = [alpha]1 + [alpha]2 - 180°, [Delta][alpha] =
+[alpha]2 - [alpha]1 - 180°.
+
+The length of the arc of meridian between the latitudes [phi]1 and
+[phi]2 is
+
+       _[phi]2                 _[phi]2
+      /                       /         (1 - e²)d[phi]
+  M = | [rho]d[phi] = [alpha] |     -----------------------
+     _/                      _/     (1 - e²sin²[phi])^(3/2)
+      [phi]1                  [phi]1
+
+where a²e² = a² - b²; instead of using the eccentricity e, put the ratio
+of the axes b:a = 1 - n:1 + n, then
+
+       _[phi]2
+      /         b(1 + n)(1 - n²)d[phi]
+  M = |     ------------------------------.
+     _/     (1 + 2n cos 2[phi] + n²)^(3/2)
+      [phi]1
+
+This, after integration, gives
+
+         /        5      5 \              /            21 \
+  M/b = ( 1 + n + -n²  + -n³) [alpha]0 - ( 3n +  3n² + --n³) [alpha]1
+         \        4      4 /              \             8 /
+
+       /15     15 \              /35  \
+    + ( --n² + --n³) [alpha]2 - ( --n³ ) [alpha]3,
+       \ 8      8 /              \24  /
+
+where
+
+  [alpha]0 = [phi]2 -  [phi]1
+  [alpha]1 = sin ([phi]2 - [phi]1) cos ([phi]2 + [phi]1)
+  [alpha]2 = sin 2([phi]2 - [phi]1) cos 2([phi]2 + [phi]1)
+  [alpha]3 = sin 3([phi]2 - [phi]1) cos 3([phi]2 + [phi]1).
+
+The part of M which depends on n³ is very small; in fact, if we
+calculate it for one of the longest arcs measured, the Russian arc, it
+amounts to only an inch and a half, therefore we omit this term, and put
+for M/b the value
+
+   /       5  \                                    /15 \
+  (l + n + --n²) [alpha]0 - (3n + 3n²) [alpha]1 + ( --n²) [alpha]2.
+   \       4  /                                    \ 8 /
+
+Now, if we suppose the observed latitudes to be affected with errors,
+and that the true latitudes are [phi]1 + x1, [phi]2 + x2; and if further
+we suppose that n1 + dn is the true value of a - b:a + b, and that n1
+itself is merely a very approximate numerical value, we get, on making
+these substitutions and neglecting the influence of the corrections x on
+the _position_ of the arc in latitude, i.e. on [phi]1 + [phi]2,
+
+         /           5   \             /        \             /15  \
+  M/b = ( 1 + n    + --n1²)[alpha]0 - (3n1 + 3n1²)[alpha]1 + ( --n1²)[alpha]2
+         \           4   /             \        /             \8   /
+       _                                             _
+      |  /    5    \       /       \       /15   \    |
+    + | ( 1 + -- n1 )a0 - ( 3 + 6n1 )a1 + ( -- n1 )a2 | dn
+      |_ \    2    /       \       /       \4    /   _|
+       _               _
+      |             da1 |
+    + | 1 + n1 - 3n --- | da0;
+      |_            da0_|
+
+here da0 = x2 - x1; and as b is only known approximately, put b = b1(1 +
+u); then we get, after dividing through by the coefficient of da0, which
+is = 1 + n1 - 3n1 cos([phi]2 - [phi]1) cos([phi]2 + [phi]1), an equation
+of the form x2 = x1 + h + fu + gv, where for convenience we put v for
+dn.
+
+Now in every measured arc there are not only the extreme stations
+determined in latitude, but also a number of intermediate stations so
+that if there be i + 1 stations there will be i equations
+
+  x2 = x1 + f1u + g1v + h1
+  x3 = x1 + f2u + g2v + h2
+   :    :                :
+   :    :                :
+  x_i = x1 + f_iu + g_iv + h_i
+
+In combining a number of different arcs of meridian, with the view of
+determining the figure of the earth, each arc will supply a number of
+equations in u and v and the corrections to its observed latitudes.
+Then, according to the method of least squares, those values of u and v
+are the most probable which render the sum of the squares of _all_ the
+errors x a minimum. The corrections x which are here applied arise not
+from errors of observation only. The mere uncertainty of a latitude, as
+determined with modern instruments, does not exceed a very small
+fraction of a second as far as errors of observation go, but no accuracy
+in observing will remove the error that may arise from local attraction.
+This, as we have seen, may amount to some seconds, so that the
+corrections x to the observed latitudes are attributable to local
+attraction. Archdeacon Pratt objected to this mode of applying least
+squares first used by Bessel; but Bessel was right, and the objection is
+groundless. Bessel found, in 1841, from ten meridian arcs with a total
+amplitude of 50°.6:
+
+  a = 3272077 toises = 6377397 metres.
+  e (ellipticity) = (a - b)/a = 1/299.15 (prob. error ± 3.2).
+
+The probable error in the length of the earth's quadrant is ± 336 m.
+
+We now give a series of some meridian-arcs measurements, which were
+utilized in 1866 by A.R. Clarke in the _Comparisons of the Standards of
+Length_, pp. 280-287; details of the calculations are given by the same
+author in his _Geodesy_ (1880), pp. 311 et seq.
+
+The data of the French arc from Formentera to Dunkirk are--
+
+  Stations.        Astronomical       Distance of
+                     Latitudes.        Parallels.
+                    °   '    "             Ft.
+  Formentera       38  39  53.17            ..
+  Mountjouy        41  21  44.96         982671.04
+  Barcelona        41  22  47.90         988701.92
+  Carcassonne      43  12  54.30        1657287.93
+  Pantheon         48  50  47.98        3710827.13
+  Dunkirk          51   2   8.41        4509790.84
+
+The distance of the parallels of Dunkirk and Greenwich, deduced from the
+extension of the triangulation of England into France, in 1862, is
+161407.3 ft., which is 3.9 ft. greater than that obtained from Captain
+Kater's triangulation, and 3.2 ft. less than the distance calculated by
+Delambre from General Roy's triangulation. The following table shows the
+data of the English arc with the distances in standard feet from
+Formentera.
+
+                    °   '    "             Ft.
+  Formentera            ..                  ..
+  Greenwich        51  28  38.30         4671198.3
+  Arbury           52  13  26.59         4943837.6
+  Clifton          53  27  29.50         5394063.4
+  Kellie Law       56  14  53.60         6413221.7
+  Stirling         57  27  49.12         6857323.3
+  Saxavord         60  49  37.21         8086820.7
+
+The latitude assigned in this table to Saxavord is not the directly
+observed latitude, which is 60° 49' 38.58", for there are here a
+cluster of three points, whose latitudes are astronomically determined;
+and if we transfer, by means of the geodesic connexion, the latitude of
+Gerth of Scaw to Saxavord, we get 60° 49' 36.59"; and if we similarly
+transfer the latitude of Balta, we get 60° 49' 36.46". The mean of
+these three is that entered in the above table.
+
+For the Indian arc in long. 77° 40' we have the following data:--
+
+                    °   '     "             Ft.
+  Punnea            8   9   31.132          ..
+  Putchapolliam    10  59   42.276       1029174.9
+  Dodagunta        12  59   52.165       1756562.0
+  Namthabad        15   5   53.562       2518376.3
+  Daumergida       18   3   15.292       3591788.4
+  Takalkhera       21   5   51.532       4697329.5
+  Kalianpur        24   7   11.262       5794695.7
+  Kaliana          29  30   48.322       7755835.9
+
+The data of the Russian arc (long. 26° 40') taken from Struve's work are
+as below:--
+
+                    °   '    "              Ft.
+  Staro Nekrasovsk 45  20   2.94            ..
+  Vodu-Luy         47   1  24.98         616529.81
+  Suprunkovzy      48  45   3.04        1246762.17
+  Kremenets        50   5  49.95        1737551.48
+  Byelin           52   2  42.16        2448745.17
+  Nemesh           54  39   4.16        3400312.63
+  Jacobstadt       56  30   4.97        4076412.28
+  Dorpat           58  22  47.56        4762421.43
+  Hogland          60   5   9.84        5386135.39
+  Kilpi-maki       62  38   5.25        6317905.67
+  Torneå           65  49  44.57        7486789.97
+  Stuor-oivi       68  40  58.40        8530517.90
+  Fuglenaes        70  40  11.23        9257921.06
+
+From the are measured in Cape Colony by Sir Thomas Maclear in long. 18°
+30', we have
+
+                        °   '     "         Ft.
+  North End            29  44   17.66       ..
+  Heerenlogement Berg  31  58    9.11     811507.7
+  Royal Observatory    33  56    3.20    1526386.8
+  Zwart Kop            34  13   32.13    1632583.3
+  Cape Point           34  21    6.26    1678375.7
+
+And, finally, for the Peruvian arc, in long. 281° 0',
+
+                   °   '     "              Ft.
+  Tarqui           3   4   32.068           ..
+  Cotchesqui       0   2   31.387        1131036.3
+
+Having now stated the data of the problem, we may seek that oblate
+ellipsoid (spheroid) which best represents the observations. Whatever
+the real figure may be, it is certain that if we suppose it an ellipsoid
+with three unequal axes, the arithmetical process will bring out an
+ellipsoid, which will agree better with all the observed latitudes than
+any spheroid would, therefore we do not _prove_ that it is an ellipsoid;
+to prove this, arcs of longitude would be required. The result for the
+spheroid may be expressed thus:--
+
+  a = 20926062 ft. = 6378206.4 metres.
+  b = 20855121 ft. = 6356583.8 metres.
+  b : a = 293.98 : 294.98.
+
+As might be expected, the sum of the squares of the 40 latitude
+corrections, viz. 153.99, is greater in this figure than in that of
+three axes, where it amounts to 138.30. For this case, in the Indian arc
+the largest corrections are at Dodagunta, + 3.87", and at Kalianpur, -
+3.68". In the Russian arc the largest corrections are + 3.76", at
+Torneå, and - 3.31", at Staro Nekrasovsk. Of the whole 40 corrections,
+16 are under 1.0", 10 between 1.0" and 2.0", 10 between 2.0" and
+3.0", and 4 over 3.0". The probable error of an observed latitude is ±
+1.42"; for the spheroidal it would be very slightly larger. This
+quantity may be taken therefore as approximately the probable amount of
+local deflection.
+
+If [rho] be the radius of curvature of the meridian in latitude [phi],
+[rho]' that perpendicular to the meridian, D the length of a degree of
+the meridian, D' the length of a degree of longitude, r the radius drawn
+from the centre of the earth, V the angle of the vertical with the
+radius-vector, then
+
+             Ft.
+     [rho]  = 20890606.6          - 106411.5 cos 2[phi] + 225.8 cos 4[phi]
+     [rho]' = 20961607.3          -  35590.9 cos 2[phi] + 45.2 cos 4[phi]
+     D      = 364609.87           -  1857.14 cos 2[phi] + 3.94 cos 4[phi]
+     D'     = 365538.48 cos [phi] -   310.17 cos 3[phi] + 0.39 cos 5[phi]
+  Log r/a   = 9.9992645           + .0007374 cos 2[phi] - .0000019 cos 4[phi]
+     V      = 700.44" sin 2[phi] - 1.19" sin 4[phi].
+
+A.R. Clarke has recalculated the elements of the ellipsoid of the earth;
+his values, derived in 1880, in which he utilized the measurements of
+parallel arcs in India, are particularly in practice. These values
+are:--
+
+  a = 20926202 ft. = 6378249 metres,
+  b = 20854895 ft. = 6356515 metres,
+  b : a = 292.465 : 293.465.
+
+  The calculation of the elements of the ellipsoid of rotation from
+  measurements of the curvature of arcs in any given azimuth by means of
+  geographical longitudes, latitudes and azimuths is indicated in the
+  article GEODESY; reference may be made to _Principal Triangulation_,
+  Helmert's _Geodasie_, and the publications of the Kgl. Preuss. Geod.
+  Inst.:--_Lotabweichungen_ (1886), and _Die europ. Längengradmessung in
+  52° Br._ (1893). For the calculation of an ellipsoid with three
+  unequal axes see _Comparison of Standards_, preface; and for
+  non-elliptical meridians, _Principal Triangulation_, p. 733.
+
+
+_Gravitation-Measurements._
+
+According to Clairault's theorem (see above) the ellipticity e of the
+mathematical surface of the earth is equal to the difference (5/2)m -ß,
+where m is the ratio of the centrifugal force at the equator to gravity
+at the equator, and ß is derived from the formula G = g(1 + ß
+sin²[phi]). Since the beginning of the 19th century many efforts have
+been made to determine the constants of this formula, and numerous
+expeditions undertaken to investigate the intensity of gravity in
+different latitudes. If m be known, it is only necessary to determine ß
+for the evaluation of e; consequently it is unnecessary to determine G
+absolutely, for the relative values of G at two known latitudes suffice.
+Such relative measurements are easier and more exact than absolute ones.
+In some cases the ordinary thread pendulum, i.e. a spherical bob
+suspended by a wire, has been employed; but more often a rigid metal
+rod, bearing a weight and a knife-edge on which it may oscillate, has
+been adopted. The main point is the constancy of the pendulum. From the
+formula for the time of oscillation of the mathematically ideal
+pendulum, t = 2 [pi] [root](l/G), l being the length, it follows that
+for two points G1/G2 = t2²/t1².
+
+In 1808 J.B. Biot commenced his pendulum observations at several
+stations in western Europe; and in 1817-1825 Captain Louis de Freycinet
+and L.I. Duperrey prosecuted similar observations far into the southern
+hemisphere. Captain Henry Kater confined himself to British stations
+(1818-1819); Captain E. Sabine, from 1819 to 1829, observed similarly,
+with Kater's pendulum, at seventeen stations ranging from the West
+Indies to Greenland and Spitsbergen; and in 1824-1831, Captain Henry
+Foster (who met his death by drowning in Central America) experimented
+at sixteen stations; his observations were completed by Francis Baily in
+London. Of other workers in this field mention may be made of F.B. Lütke
+(1826-1829), a Russian rear-admiral, and Captains J.B. Basevi and W.T.
+Heaviside, who observed during 1865 to 1873 at Kew and at 29 Indian
+stations, particularly at Moré in the Himalayas at a height of 4696
+metres. Of the earlier absolute determinations we may mention those of
+Biot, Kater, and Bessel at Paris, London and Königsberg respectively.
+The measurements were particularly difficult by reason of the length of
+the pendulums employed, these generally being second-pendulums over 1
+metre long. In about 1880, Colonel Robert von Sterneck of Austria
+introduced the half-second pendulum, which permitted far quicker and
+more accurate work. The use of these pendulums spread in all countries,
+and the number of gravity stations consequently increased: in 1880 there
+were about 120, in 1900 there were about 1600, of which the greater
+number were in Europe. Sir E. Sabine[6] calculated the ellipticity to be
+1/288.5, a value shown to be too high by Helmert, who in 1884, with the
+aid of 120 stations, gave the value 1/299.26,[7] and in 1901, with about
+1400 stations, derived the value 1/298.3.[8] The reason for the
+excessive estimate of Sabine is that he did not take into account the
+systematic difference between the values of G for continents and
+islands; it was found that in consequence of the constitution of the
+earth's crust (Pratt) G is greater on small islands of the ocean than
+on continents by an amount which may approach to 0.3 cm. Moreover,
+stations in the neighbourhood of coasts shelving to deep seas have a
+surplus, but a little smaller. Consequently, Helmert conducted his
+calculations of 1901 for continents and coasts separately, and obtained
+G for the coasts 0.036 cm. greater than for the continents, while the
+value of ß remained the same. The mean value, reduced to continents, is
+
+  G = 978.03(1 + 0.005302 sin²[phi] - 0.000007 sin² 2[phi])cm/sec².
+
+The small term involving sin² 2[phi] could not be calculated with
+sufficient exactness from the observations, and is therefore taken from
+the theoretical views of Sir G.H. Darwin and E. Wiechert. For the
+constant g = 978.03 cm. another correction has been suggested (1906) by
+the absolute determinations made by F. Kühnen and Ph. Furtwängler at
+Potsdam.[9]
+
+  A report on the pendulum measurements of the 19th century has been
+  given by Helmert in the _Comptes rendus des séances de la 13^e
+  conférence générale de l'Association Géod. Internationale à Paris_
+  (1900), ii. 139-385.
+
+A difficulty presents itself in the case of the application of
+measurements of gravity to the determination of the figure of the earth
+by reason of the extrusion or standing out of the land-masses
+(continents, &c.) above the sea-level. The potential of gravity has a
+different mathematical expression outside the masses than inside. The
+difficulty is removed by assuming (with Sir G.G. Stokes) the vertical
+condensation of the masses on the sea-level, without its form being
+considerably altered (scarcely 1 metre radially). Further, the value of
+gravity (g) measured at the height H is corrected to sea-level by +
+2gH/R, where R is the radius of the earth. Another correction, due to P.
+Bouguer, is -(3/2)g[delta]H/[rho]R, where [delta] is the density of the
+strata of height H, and [rho] the mean density of the earth. These two
+corrections are represented in "Bouguer's Rule": g_H = g_s(1 - 2H/R +
+3[delta]H/2[rho]R), where g_H is the gravity at height H, and g_s the
+value at sea-level. This is supposed to take into account the attraction
+of the elevated strata or plateau; but, from the analytical method, this
+is not correct; it is also disadvantageous since, in general, the
+land-masses are compensated subterraneously, by reason of the isostasis
+of the earth's crust.
+
+In 1849 Stokes showed that the normal elevations N of the geoid towards
+the ellipsoid are calculable from the deviations [Delta]g of the
+acceleration of gravity, i.e. the differences between the observed g and
+the value calculated from the normal G formula. The method assumes that
+gravity is measured on the earth's surface at a sufficient number of
+points, and that it is conformably reduced. In order to secure the
+convergence of the expansions in spherical harmonics, it is necessary to
+assume all masses outside a surface parallel to the surface of the sea
+at a depth of 21 km. (= R × ellipticity) to be condensed on this surface
+(Helmert, _Geod._ ii. 172). In addition to the reduction with 2gH/R,
+there still result small reductions with mountain chains and coasts, and
+somewhat larger ones for islands. The sea-surface generally varies but
+very little by this condensation. The elevation (N) of the geoid is then
+equal to
+         _
+        /[pi]
+  N = R |  FG^(-1) [Delta]g_[psi] d[psi],
+       _/
+
+where [psi] is the spherical distance from the point N, and
+[Delta]g_[psi] denotes the mean value of [Delta]g for all points in the
+same distance [psi] around; F is a function of [psi], and has the
+following values:--
+
+  +-------+-------+
+  | [Psi]=|   F=  |
+  +-------+-------+
+  |    0° |  1    |
+  |   10° |  1.22 |
+  |   20° |  0.94 |
+  |   30° |  0.47 |
+  |   40° | -0.06 |
+  |   50° | -0.54 |
+  |   60° | -0.90 |
+  |   70° | -1.08 |
+  |   80° | -1.08 |
+  |   90° | -0.91 |
+  |  100° | -0.62 |
+  |  110° | -0.27 |
+  |  120° | +0.08 |
+  |  130° |  0.36 |
+  |  140° |  0.53 |
+  |  150° |  0.56 |
+  |  160° |  0.46 |
+  |  170° |  0.26 |
+  |  180° |  0    |
+  +-------+-------+
+
+H. Poincaré (_Bull. Astr._, 1901, p. 5) has exhibited N by means of
+Lamé's functions; in this case the condensation is effected on an
+ellipsoidal surface, which approximates to the geoid. This condensation
+is, in practice, the same as to the geoid itself.
+
+If we imagine the outer land-masses to be condensed on the sea-level,
+and the inner masses (which, together with the outer masses, causes the
+deviation of the geoid from the ellipsoid) to be compensated in the
+sea-level by a disturbing stratum (which, according to Gauss, is
+possible), and if these masses of both kinds correspond at the point N
+to a stratum of thickness D and density [delta], then, according to
+Helmert (_Geod._ ii. 260) we have approximately
+
+             3  g   /[delta]D    \
+  [Delta]g = -- -- ( -------- - N ).
+             2  R   \  [rho]     /
+
+Since N slowly varies empirically, it follows that in restricted regions
+(of a few 100 km. in diameter) [Delta]g is a measure of the variation of
+D. By applying the reduction of Bouguer to g, D is diminished by H and
+only gives the thickness of the ideal disturbing mass which corresponds
+to the perturbations due to subterranean masses. [Delta]g has positive
+values on coasts, small islands, and high and medium mountain chains,
+and occasionally in plains; while in valleys and at the foot of mountain
+ranges it is negative (up to 0.2 cm.). We conclude from this that the
+masses of smaller density existing under high mountain chains lie not
+only vertically underneath but also spread out sideways.
+
+
+_The European Arc of Parallel in 52° Lat._
+
+Many measurements of degrees of longitudes along central parallels in
+Europe were projected and partly carried out as early as the first half
+of the 19th century; these, however, only became of importance after the
+introduction of the electric telegraph, through which calculations of
+astronomical longitudes obtained a much higher degree of accuracy. Of
+the greatest moment is the measurement near the parallel of 52° lat.,
+which extended from Valentia in Ireland to Orsk in the southern Ural
+mountains over 69° long, (about 6750 km.). F.G.W. Struve, who is to be
+regarded as the father of the Russo-Scandinavian latitude-degree
+measurements, was the originator of this investigation. Having made the
+requisite arrangements with the governments in 1857, he transferred
+them to his son Otto, who, in 1860, secured the co-operation of England.
+A new connexion of England with the continent, via the English Channel,
+was accomplished in the next two years; whereas the requisite
+triangulations in Prussia and Russia extended over several decennaries.
+The number of longitude stations originally arranged for was 15; and the
+determinations of the differences in longitude were uniformly commenced
+by the Russian observers E.I. von Forsch, J.I. Zylinski, B. Tiele and
+others; Feaghmain (Valentia) being reserved for English observers. With
+the concluding calculation of these operations, newer determinations of
+differences of longitudes were also applicable, by which the number of
+stations was brought up to 29. Since local deflections of the plumb-line
+were suspected at Feaghmain, the most westerly station, the longitude
+(with respect to Greenwich) of the trigonometrical station Killorglin at
+the head of Dingle Bay was shortly afterwards determined.
+
+  The results (1891-1894) are given in volumes xlvii. and l. of the
+  memoirs (Zapiski) of the military topographical division of the
+  Russian general staff, volume li. contains a reconnexion of Orsk. The
+  observations made west of Warsaw are detailed in the _Die europ.
+  Längengradmessung in 52° Br._, i. and ii., 1893, 1896, published by
+  the Kgl. Preuss. Geod. Inst.
+
+The following figures are quoted from Helmert's report "Die Grösse der
+Erde" (_Sitzb. d. Berl. Akad. d. Wiss._, 1906, p. 535):--
+
+  _Easterly Deviation of the Astronomical Zenith_.
+
+    Name.                   Longitude.
+                          °    '      "
+  Feaghmain             -10   21    -3.3
+  Killorglin            - 9   47    +2.8
+  Haverfordwest         - 4   58    +1.6
+  Greenwich               0    0    +1.5
+  Rosendaël-Nieuport    + 2   35    -1.7
+  Bonn                  + 7    6    -4.4
+  Göttingen             + 9   57    -2.4
+  Brocken               +10   37    +2.3
+  Leipzig               +12   23    +2.7
+  Rauenberg-Berlin      +13   23    +1.7
+  Grossenhain           +13   33    -2.9
+  Schneekoppe           +15   45    +0.1
+  Springberg            +16   37    +0.8
+  Breslau-Rosenthal     +17    2    +3.5
+  Trockenberg           +18   53    -0.5
+  Schönsee              +18   54    -2.9
+  Mirov                 +19   18    +2.2
+  Warsaw                +21    2    +1.9
+  Grodno                +23   50    -2.8
+  Bobruisk              +29   14    +0.5
+  Orel                  +36    4    +4.4
+  Lipetsk               +39   36    +0.2
+  Saratov               +46    3    +6.4
+  Samara                +50    5    -2.6
+  Orenburg              +55    7    +1.7
+  Orsk                  +58   34    -8.0
+
+These deviations of the plumb-line correspond to an ellipsoid having an
+equatorial radius (a) of nearly 6,378,000 metres (prob. error ± 70
+metres) and an ellipticity 1/299.15. The latter was taken for granted;
+it is nearly equal to the result from the gravity-measurements; the
+value for a then gives [Sigma][eta]² a minimum (nearly). The
+astronomical values of the geographical longitudes (with regard to
+Greenwich) are assumed, according to the compensation of longitude
+differences carried out by van de Sande Bakhuyzen (_Comp. rend, des
+séances de la commission permanente de l'Association Géod.
+Internationale à Genève, 1893, annexe A.I._). Recent determinations
+(Albrecht, _Astr. Nach._, 3993/4) have introduced only small alterations
+in the deviations, a being slightly increased.
+
+Of considerable importance in the investigation of the great arc was
+the representation of the linear lengths found in different countries,
+in terms of the same unit. The necessity for this had previously
+occurred in the computation of the figure of the earth from
+latitude-degree-measurements. A.R. Clarke instituted an extensive
+series of comparisons at Southampton (see _Comparisons of Standards of
+Length of England, France, Belgium, Prussia, Russia, India and
+Australia, made at the Ordnance Survey Office, Southampton, 1866_, and
+a paper in the _Philosophical Transactions_ for 1873, by Lieut.-Col.
+A.R. Clarke, C.B., R.E., on the further comparisons of the standards
+of Austria, Spain, the United States, Cape of Good Hope and Russia) and
+found that 1 toise = 6.39453348 ft., 1 metre = 3.28086933 ft.
+
+In 1875 a number of European states concluded the metre convention, and
+in 1877 an international weights-and-measures bureau was established at
+Breteuil. Until this time the metre was determined by the end-surfaces
+of a platinum rod (_mètre des archives_); subsequently, rods of
+platinum-iridium, of cross-section H, were constructed, having engraved
+lines at both ends of the bridge, which determine the distance of a
+metre. There were thirty of the rods which gave as accurately as
+possible the length of the metre; and these were distributed among the
+different states (see WEIGHTS AND MEASURES). Careful comparisons with
+several standard toises showed that the metre was not exactly equal to
+443,296 lines of the toise, but, in round numbers, 1/75000 of the length
+smaller. The metre according to the older relation is called the "legal
+metre," according to the new relation the "international metre." The
+values are (see _Europ. Längengradmessung_, i. p. 230):--
+
+  Legal metre = 3.28086933 ft., International metre = 3.2808257 ft.
+
+The values of a given above are in terms of the international metre; the
+earlier ones in legal metres, while the gravity formulae are in
+international metres.
+
+
+_The International Geodetic Association (Internationale Erdmessung)._
+
+On the proposition of the Prussian lieutenant-general, Johann Jacob
+Baeyer, a conference of delegates of several European states met at
+Berlin in 1862 to discuss the question of a "Central European
+degree-measurement." The first general conference took place at Berlin
+two years later; shortly afterwards other countries joined the movement,
+which was then named "The European degree-measurement." From 1866 till
+1886 Prussia had borne the expense incident to the central bureau at
+Berlin; but when in 1886 the operations received further extension and
+the title was altered to "The International Earth-measurement" or
+"International Geodetic Association," the co-operating states made
+financial contributions to this purpose. The central bureau is
+affiliated with the Prussian Geodetic Institute, which, since 1892, has
+been situated on the Telegraphenberg near Potsdam. After Baeyer's death
+Prof. Friedrich Robert Helmert was appointed director. The funds are
+devoted to the advancement of such scientific works as concern all
+countries and deal with geodetic problems of a general or universal
+nature. During the period 1897-1906 the following twenty-one countries
+belonged to the association:--Austria, Belgium, Denmark, England,
+France, Germany, Greece, Holland, Hungary, Italy, Japan, Mexico, Norway,
+Portugal, Rumania, Russia, Servia, Spain, Sweden, Switzerland and the
+United States of America. At the present time general conferences take
+place every three years.[10]
+
+Baeyer projected the investigation of the curvature of the meridians and
+the parallels of the mathematical surface of the earth stretching from
+Christiania to Palermo for 12 degrees of longitude; he sought to
+co-ordinate and complete the network of triangles in the countries
+through which these meridians passed, and to represent his results by a
+common unit of length. This proposition has been carried out, and
+extended over the greater part of Europe; as a matter of fact, the
+network has, with trifling gaps, been carried over the whole of western
+and central Europe, and, by some chains of triangles, over European
+Russia. Through the co-operation of France, the network has been
+extended into north Africa as far as the geographical latitude of 32°;
+in Greece a network, united with those of Italy and Bosnia, has been
+carried out by the Austrian colonel, Heinrich Hartl; Servia has
+projected similar triangulations; Rumania has begun to make the triangle
+measurements, and three base lines have been measured by French
+officers with Brunner's apparatus. At present, in Rumania, there is
+being worked a connexion between the arc of parallel in lat. 47°/48° in
+Russia (stretching from Astrakan to Kishinev) with Austria-Hungary. In
+the latter country and in south Bavaria the connecting triangles for
+this parallel have been recently revised, as well as the French chain on
+the Paris parallel, which has been connected with the German net by the
+co-operation of German and French geodesists. This will give a long arc
+of parallel, really projected in the first half of the 19th century. The
+calculation of the Russian section gives, with an assumed ellipticity of
+1/299.15, the value a = 6377350 metres; this is rather uncertain, since
+the arc embraces only 19° in longitude.
+
+We may here recall that in France geodetic studies have recovered their
+former expansion under the vigorous impulse of Colonel (afterwards
+General) François Perrier. When occupied with the triangulation of
+Algeria, Colonel Perrier had conceived the possibility of the geodetic
+junction of Algeria to Spain, over the Mediterranean; therefore the
+French meridian line, which was already connected with England, and was
+thus produced to the 60th parallel, could further be linked to the
+Spanish triangulation, cross thence into Algeria and extend to the
+Sahara, so as to form an arc of about 30° in length. But it then became
+urgent to proceed to a new measurement of the French arc, between
+Dunkirk and Perpignan. In 1869 Perrier was authorized to undertake that
+revision. He devoted himself to that work till the end of his career,
+closed by premature death in February 1888, at the very moment when the
+_Dépôt de la guerre_ had just been transformed into the Geographical
+Service of the Army, of which General F. Perrier was the first director.
+His work was continued by his assistant, Colonel (afterwards General)
+J.A.L. Bassot. The operations concerning the revision of the French arc
+were completed only in 1896. Meanwhile the French geodesists had
+accomplished the junction of Algeria to Spain, with the help of the
+geodesists of the Madrid Institute under General Carlos Ibañez (1879),
+and measured the meridian line between Algiers and El Aghuat (1881).
+They have since been busy in prolonging the meridians of El Aghuat and
+Biskra, so as to converge towards Wargla, through Ghardaïa and Tuggurt.
+The fundamental co-ordinates of the Panthéon have also been obtained
+anew, by connecting the Panthéon and the Paris Observatory with the five
+stations of Bry-sur-Marne, Morlu, Mont Valérien, Chatillon and
+Montsouris, where the observations of latitude and azimuth have been
+effected.[11]
+
+According to the calculations made at the central bureau of the
+international association on the great meridian arc extending from the
+Shetland Islands, through Great Britain, France and Spain to El Aghuat in
+Algeria, a = 6377935 metres, the ellipticity being assumed as 1/299.15.
+The following table gives the difference: astronomical-geodetic latitude.
+The net does not follow the meridian exactly, but deviates both to the
+west and to the east; actually, the meridian of Greenwich is nearer the
+mean than that of Paris (Helmert, _Grösse d. Erde_).
+
+  _West Europe-Africa Meridian-arc._[12]
+
+  Name.                Latitude.   A.-G.
+                        °   '        "
+  Saxavord             60  49.6    -4.0
+  Balta                60  45.0    -6.1
+  Ben Hutig            58  33.1    +0.3
+  Cowhythe             57  41.1    +7.3
+  Great Stirling       57  27.8    -2.3
+  Kellie Law           56  14.9    -3.7
+  Calton Hill          55  57.4    +3.5
+  Durham               54  46.1    -0.9
+  Burleigh Moor        54  34.3    +2.1
+  Clifton Beacon       53  27.5    +1.3
+  Arbury Hill          52  13.4    -3.0
+  Greenwich            51  28.6    -2.5
+  Nieuport             51   7.8    -0.4
+  Rosendaël            51   2.7    -0.9
+  Lihons               49  49.9    +0.5
+  Panthéon             48  50.8    -0.0
+  Chevry               48   0.5    +2.2
+  Saligny le Vif       47   2.7    +3.0
+  Arpheuille           46  13.7    +6.3
+  Puy de Dôme          45  46.5    +7.0
+  Rodez                44  21.4    +1.7
+  Carcassonne          43  13.3    +0.7
+  Rivesaltes           42  45.2    -0.7
+  Montolar             41  38.5    +3.6
+  Lérida               41  37.0    -0.2
+  Javalon              40  13.8    -0.2
+  Desierto             40   5.0    -4.5
+  Chinchilla           38  55.2    +2.2
+  Mola de Formentera   38  39.9    -1.2
+  Tetíca               37  15.2    +3.5
+  Roldan               36  56.6    -6.0
+  Conjuros             36  44.4   -12.6
+  Mt. Sabiha           35  39.6    +6.5
+  Nemours              35   5.8    +7.4
+  Bouzaréah            36  48.0    +2.9
+  Algiers (Voirol)     36  45.1    -9.1
+  Guelt ès Stel        35   7.8    -1.0
+  El Aghuat            33  48.0    -2.8
+
+[Illustration]
+
+While the radius of curvature of this arc is obviously not uniform
+(being, in the mean, about 600 metres greater in the northern than in
+the southern part), the Russo-Scandinavian meridian arc (from 45° to
+70°), on the other hand, is very uniformly curved, and gives, with an
+ellipticity of 1/299.15, a = 6378455 metres; this arc gives the
+plausible value 1/298.6 for the ellipticity. But in the case of this arc
+the orographical circumstances are more favourable.
+
+The west-European and the Russo-Scandinavian meridians indicate another
+anomaly of the geoid. They were connected at the Central Bureau by means
+of east-to-west triangle chains (principally by the arc of parallel
+measurements in lat. 52°); it was shown that, if one proceeds from the
+west-European meridian arcs, the differences between the astronomical
+and geodetic latitudes of the Russo-Scandinavian arc become some 4"
+greater.[13]
+
+The central European meridian, which passes through Germany and the
+countries adjacent on the north and south, is under review at Potsdam
+(see the publications of the Kgl. Preuss. Geod. Inst., _Lotabweichungen_,
+Nos. 1-3). Particular notice must be made of the Vienna meridian, now
+carried southwards to Malta. The Italian triangulation is now complete,
+and has been joined with the neighbouring countries on the north, and
+with Tunis on the south.
+
+The United States Coast and Geodetic Survey has published an account of
+the transcontinental triangulation and measurement of an arc of the
+parallel of 39°, which extends from Cape May (New Jersey), on the
+Atlantic coast, to Point Arena (California), on the Pacific coast, and
+embraces 48° 46' of longitude, with a linear development of about 4225
+km. (2625 miles). The triangulation depends upon ten base-lines, with an
+aggregate length of 86 km. the longest exceeding 17 km. in length, which
+have been measured with the utmost care. In crossing the Rocky
+Mountains, many of its sides exceed 100 miles in length, and there is
+one side reaching to a length of 294 km., or 183 miles; the altitude of
+many of the stations is also considerable, reaching to 4300 metres, or
+14,108 ft., in the case of Pike's Peak, and to 14,421 ft. at Elbert
+Peak, Colo. All geometrical conditions subsisting in the triangulation
+are satisfied by adjustment, inclusive of the required accord of the
+base-lines, so that the same length for any given line is found, no
+matter from what line one may start.[14]
+
+Over or near the arc were distributed 109 latitude stations, occupied
+with zenith telescopes; 73 azimuth stations; and 29 telegraphically
+determined longitudes. It has thus been possible to study in a very
+complete manner the deviations of the vertical, which in the mountainous
+regions sometimes amount to 25 seconds, and even to 29 seconds.
+
+With the ellipticity 1/299.15, a = 6377897 ± 65 metres (prob. error); in
+this calculation, however, some exceedingly perturbed stations are
+excluded; for the employed stations the mean perturbation in longitude
+is ± 4.9" (zenith-deflection east-to-west ± 3.8").
+
+The computations relative to another arc, the "eastern oblique arc of
+the United States," are also finished.[15] It extends from Calais
+(Maine) in the north-east, to the Gulf of Mexico, and terminates at New
+Orleans (Louisiana), in the south. Its length is 2612 km. (1623 miles),
+the difference of latitude 15° 1', and of longitude 22° 47'. In the
+main, the triangulation follows the Appalachian chain of mountains,
+bifurcating once, so as to leave an oval space between the two branches.
+It includes among its stations Mount Washington (1920 metres) and Mount
+Mitchell (2038 metres). It depends upon six base-lines, and the
+adjustment is effected in the same manner as for the arc of the
+parallel. The astronomical data have been afforded by 71 latitude
+stations, 17 longitude stations, and 56 azimuth stations, distributed
+over the whole extent of the arc. The resulting dimensions of an
+osculating spheroid were found to be
+
+  a = 6378157 metres ± 90 (prob. error),
+  e(ellipticity) = 1/304.5 ± 1.9 (prob. error).
+
+With the ellipticity 1/399.15, a = 6378041 metres ± 80 (prob. er.).
+
+During the years 1903-1906 the United States Coast and Geodetic Survey,
+under the direction of O.H. Tittmann and the special management of John
+F. Hayford, executed a calculation of the best ellipsoid of rotation for
+the United States. There were 507 astronomical determinations employed,
+all the stations being connected through the net-work of triangles. The
+observed latitudes, longitude and azimuths were improved by the
+attractions of the earth's crust on the hypothesis of isostasis for
+three depths of the surface of 114, 121 and 162 km., where the isostasis
+is complete. The land-masses, within the distance of 4126 km., were
+taken into consideration. In the derivation of an ellipsoid of rotation,
+the first case proved itself the most favourable, and there resulted:--
+
+  a = 6378283 metres ± 74 (prob. er.), ellipticity
+    = 1/297.8 ± 0.9 (prob. er.).
+
+The most favourable value for the depth of the isostatic surface is
+approximately 114 km.
+
+The measurement of a great meridian arc, in long. 98° W., has been
+commenced; it has a range of latitude of 23°, and will extend over 50°
+when produced southwards and northwards by Mexico and Canada. It may
+afterwards be connected with the arc of Quito. A new measurement of the
+meridian arc of Quito was executed in the years 1901-1906 by the
+_Service géographique_ of France under the direction of the Académie des
+Sciences, the ground having been previously reconnoitred in 1899. The
+new arc has an amplitude in latitude of 5° 53' 33", and stretches from
+Tulcan (lat. 0° 48' 25") on the borders of Columbia and Ecuador, through
+Columbia to Payta (lat. -5° 5' 8") in Peru. The end-points, at which the
+chain of triangles has a slight north-easterly trend, show a longitude
+difference of 3°. Of the 74 triangle points, 64 were latitude stations;
+6 azimuths and 8 longitude-differences were measured, three base-lines
+were laid down, and gravity was determined from six points, in order to
+maintain indications over the general deformation of the geoid in that
+region. Computations of the attraction of the mountains on the
+plumb-line are also being considered. The work has been much delayed by
+the hardships and difficulties encountered. It was conducted by
+Lieut.-Colonel Robert Bourgeois, assisted by eleven officers and
+twenty-four soldiers of the geodetic branch of the _Service
+géographique_. Of these officers mention may be made of Commandant E.
+Maurain, who retired in 1904 after suffering great hardships; Commandant
+L. Massenet, who died in 1905; and Captains I. Lacombe, A. Lallemand,
+and Lieut. Georges Perrier (son of General Perrier). It is conceivable
+that the chain of triangles in longitude 98° in North America may be
+united with that of Ecuador and Peru: a continuous chain over the whole
+of America is certainly but a question of time. During the years
+1899-1902 the measurement of an arc of meridian was made in the extreme
+north, in Spitzbergen, between the latitudes 76° 38' and 80° 50',
+according to the project of P.G. Rosén. The southern part was determined
+by the Russians--O. Bäcklund, Captain D.D. Sergieffsky, F.N.
+Tschernychev, A. Hansky and others--during 1899-1901, with the aid of 1
+base-line, 15 trigonometrical, 11 latitude and 5 gravity stations. The
+northern part, which has one side in common with the southern part, has
+been determined by Swedes (Professors Rosén, father and son, E. Jäderin,
+T. Rubin and others), who utilized 1 base-line, 9 azimuth measurements,
+18 trigonometrical, 17 latitude and 5 gravity stations. The party worked
+under excessive difficulties, which were accentuated by the arctic
+climate. Consequently, in the first year, little headway was made.[16]
+
+Sir David Gill, when director of the Royal Observatory, Cape Town,
+instituted the magnificent project of working a latitude-degree
+measurement along the meridian of 30° long. This meridian passes through
+Natal, the Transvaal, by Lake Tanganyika, and from thence to Cairo;
+connexion with the Russo-Scandinavian meridian arc of the same longitude
+should be made through Asia Minor, Turkey, Bulgaria and Rumania. With
+the completion of this project a continuous arc of 105° in latitude will
+have been measured.[17]
+
+Extensive triangle chains, suitable for latitude-degree measurements,
+have also been effected in Japan and Australia.
+
+Besides, the systematization of gravity measurements is of importance,
+and for this purpose the association has instituted many reforms. It has
+ensured that the relative measurements made at the stations in different
+countries should be reduced conformably with the absolute determinations
+made at Potsdam; the result was that, in 1906, the intensities of
+gravitation at some 2000 stations had been co-ordinated. The intensity
+of gravity on the sea has been determined by the comparison of
+barometric and hypsometric observations (Mohn's method). The
+association, at the proposal of Helmert, provided the necessary funds
+for two expeditions:--English Channel--Rio de Janeiro, and the Red
+Sea--Australia--San Francisco--Japan. Dr O. Hecker of the central bureau
+was in charge; he successfully overcame the difficulties of the work,
+and established the tenability of the isostatic hypothesis, which
+necessitates that the intensity of gravity on the deep seas has, in
+general, the same value as on the continents (without regard to the
+proximity of coasts).[18]
+
+As the result of the more recent determinations, the ellipticity,
+compression or flattening of the ellipsoid of the earth may be assumed
+to be very nearly 1/298.3; a value determined in 1901 by Helmert from
+the measurements of gravity. The semi-major axis, a, of the meridian
+ellipse may exceed 6,378,000 inter. metres by about 200 metres. The
+central bureau have adopted, for practical reasons, the value 1/299.15,
+after Bessel, for which tables exist; and also the value a =
+6377397.155(1 + 0.0001).
+
+The methods of theoretical astronomy also permit the evaluation of these
+constants. The semi-axis a is calculable from the parallax of the moon
+and the acceleration of gravity on the earth; but the results are
+somewhat uncertain: the ellipticity deduced from lunar perturbations is
+1/297.8 ± 2 (Helmert, _Geodäsie_, ii. pp. 460-473); William Harkness
+(_The Solar Parallax and its related Constants_, 1891) from all possible
+data derived the values: ellipticity = 1/300.2 ± 3, a = 6377972 ± 125
+metres. Harkness also considered in this investigation the relation of
+the ellipticity to precession and nutation; newer investigations of the
+latter lead to the limiting values 1/296, 1/298 (Wiechert). It was
+clearly noticed in this method of determination that the influence of
+the assumption as to the density of the strata in the interior of the
+earth was but very slight (Radau, _Bull. astr._ ii. (1885) 157). The
+deviations of the geoid from the flattened ellipsoid of rotation with
+regard to the heights (the directions of normals being nearly the same)
+will scarcely exceed ± 100 metres (Helmert).[19]
+
+The basis of the degree- and gravity-measurements is actually formed by
+a stationary sea-surface, which is assumed to be level. However, by the
+influence of winds and ocean currents the mean surface of the sea near
+the coasts (which one assumes as the fundamental sea-surface) can
+deviate somewhat from a level surface. According to the more recent
+levelling it varies at the most by only some decimeters.[20]
+
+It is well known that the masses of the earth are continually undergoing
+small changes; the earth's crust and sea-surface reciprocally oscillate,
+and the axis of rotation vibrates relatively to the body of the earth.
+The investigation of these problems falls in the programme of the
+Association. By continued observations of the water-level on sea-coasts,
+results have already been obtained as to the relative motions of the
+land and sea (cf. GEOLOGY); more exact levelling will, in the course of
+time, provide observations on countries remote from the sea-coast. Since
+1900 an international service has been organized between some
+astronomical stations distributed over the north parallel of 39° 8', at
+which geographical latitudes are observed whenever possible. The
+association contributes to all these stations, supporting four entirely:
+two in America, one in Italy, and one in Japan; the others partially
+(Tschardjui in Russia, and Cincinnati observatory). Some observatories,
+especially Pulkowa, Leiden and Tokyo, take part voluntarily. Since 1906
+another station for South America and one for Australia in latitude -31°
+55' have been added. According to the existing data, geographical
+latitudes exhibit variations amounting to ±0.25", which, for the greater
+part, proceed from a twelve- and a fourteen-month period.[21]
+     (A. R. C; F. R. H.)
+
+
+FOOTNOTES:
+
+  [1] _Eratosthenes Batavus, seu de terrae ambitus vera quantitate
+    suscitatus, a Willebrordo Snellio, Lugduni-Batavorum_ (1617).
+
+  [2] O. Callandreau, "Mémoire sur la théorie de la figure des
+    planètes," _Ann. obs. de Paris_ (1889); G.H. Darwin, "The Theory of
+    the Figure of the Earth carried to the Second Order of Small
+    Quantities," _Mon. Not. R.A.S._, 1899; E. Wiechert, "Über die
+    Massenverteilung im Innern der Erde," _Nach. d. kön. G. d. W. zu
+    Gött._, 1897.
+
+  [3] See I. Todhunter, _Proc. Roy. Soc._, 1870.
+
+  [4] J.H. Jeans, "On the Vibrations and Stability of a Gravitating
+    Planet," _Proc. Roy. Soc._ vol. 71; G.H. Darwin, "On the Figure and
+    Stability of a liquid Satellite," _Phil. Trans._ 206, p. 161; A.E.H.
+    Love, "The Gravitational Stability of the Earth," _Phil. Trans._ 207,
+    p. 237; _Proc. Roy. Soc._ vol. 80.
+
+  [5] _Survey of India_, "The Attraction of the Himalaya Mountains upon
+    the Plumb Line in India" (1901), p. 98.
+
+  [6] _Account of Experiments to Determine the Figure of the Earth by
+    means of a Pendulum vibrating Seconds in Different Latitudes_ (1825).
+
+  [7] Helmert, _Theorien d. höheren Geod._ ii., Leipzig, 1884.
+
+  [8] Helmert, _Sitzber. d. kgl. preuss. Ak. d. Wiss. zu Berlin_
+    (1901), p. 336.
+
+  [9] "Bestimmung der absoluten Grösse der Schwerkraft zu Potsdam mit
+    Reversionspendeln" (_Veröffentlichung des kgl. preuss. Geod. Inst._,
+    N.F., No. 27).
+
+  [10] _Die Königl. Observatorien für Astrophysik, Meteorologie und
+    Geodäsie bei Potsdam_ (Berlin, 1890); _Verhandlungen der I.
+    Allgemeinen Conferenz der Bevollmächtigten zur mitteleurop.
+    Gradmessung_, October, 1864, in Berlin (Berlin, 1865); A. Hirsch,
+    _Verhandlungen der VIII. Allg. Conf. der Internationalen Erdmessung_,
+    October, 1886, in Berlin (Berlin, 1887); and _Verhandlungen der XI.
+    Allg. Conf. d. I. E._, October, 1895, in Berlin (1896).
+
+  [11] Ibañez and Perrier, _Jonction géod. et astr. de l'Algérie avec
+    l'Espagne_ (Paris, 1886); _Mémorial du dépôt général de la guerre_,
+    t. xii.: _Nouvelle méridienne de France_ (Paris, 1885, 1902, 1904);
+    _Comptes rendus des séances de la 12^e-19^e conférence générale de
+    l'Assoc. Géod. Internat._, 1898 at Stuttgart, 1900 at Paris, 1903 at
+    Copenhagen, 1906 at Budapest (Berlin, 1899, 1901, 1904, 1908); A.
+    Ferrero, _Rapport sur les triangulations, prés. à la 12^e conf. gén.
+    1898_.
+
+  [12] R. Schumann, _C. r. de Budapest_, p. 244.
+
+  [13] O. and A. Börsch, "Verbindung d. russ.-skandinav. mit der
+    franz.-engl. Breitengradmessung" (_Verhandlungen der 9. Allgem. Conf.
+    d. I. E. in Paris, 1889_, Ann. xi.).
+
+  [14] U.S. Coast and Geodetic Survey; H.S. Pritchett, superintendent.
+    _The Transcontinental Triangulation and the American Arc of the
+    Parallel_, by C.A. Schott (Washington, 1900).
+
+  [15] U.S. Coast and Geodetic Survey; O.H. Tittmann, superintendent.
+    _The Eastern Oblique Arc of the United States_, by C.A. Schott
+    (1902).
+
+  [16] _Missions scientifiques pour la mesure d'un arc de méridien au
+    Spitzberg entreprises en 1899-1902 sous les auspices des
+    gouvernements russe et suédois._ _Mission russe_ (St Pétersbourg,
+    1904); _Mission suédoise_ (Stockholm, 1904).
+
+  [17] Sir David Gill, _Report on the Geodetic Survey of South Africa,
+    1833-1892_ (Cape Town, 1896), vol. ii. 1901, vol. iii. 1905.
+
+  [18] O. Hecker, _Bestimmung der Schwerkraft a. d. Atlantischen Ozean_
+    (Veröffentl. d. Kgl. Preuss. Geod. Inst. No. 11), Berlin, 1903.
+
+  [19] F.R. Helmert. "Neuere Fortschritte in der Erkenntnis der math.
+    Erdgestalt" (_Verhandl. des VII. Internationalen
+    Geographen-Kongresses, Berlin, 1899_), London, 1901.
+
+  [20] C. Lallemand, "Rapport sur les travaux du service du nivellement
+    général de la France, de 1900 à 1906" (_Comp. rend. de la 14^e conf.
+    gén. de l'Assoc. Géod-Intern., 1903_, p. 178).
+
+  [21] T. Albrecht, _Resultate des internat. Breitendienstes_, i. and
+    ii. (Berlin, 1903 and 1906); F. Klein and A. Sommerfeld, _Über die
+    Theorie des Kreisels_, iii. p. 672; R. Spitaler, "Die periodischen
+    Luftmassenverschiebungen und ihr Einfluss auf die Lagenänderung der
+    Erdaxe" (_Petermanns Mitteilungen, Ergänzungsheft_, 137); S. Newcomb,
+    "Statement of the Theoretical Laws of the Polar Motion"
+    (_Astronomical Journal_, 1898, xix. 158); F.R. Helmert, "Zur
+    Erklärung der beobachteten Breitenänderungen" (_Astr. Nachr._ No.
+    3014); J. Weeder, "The 14-monthly period of the motion of the Pole
+    from determinations of the azimuth of the meridian marks of the
+    Leiden observatory" (_Kon. Ak. van Wetenschappen to Amsterdam_,
+    1900); A. Sokolof, "Détermination du mouvement du pôle terr. au moyen
+    des mires méridiennes de Poulkovo" (_Mél. math. et astr._ vii.,
+    1894); J. Bonsdorff, "Beobachtungen von [delta] Cassiopejae mit dem
+    grossen Zenitteleskop" (_Mitteilungen der Nikolai-Hauptsternwarte zu
+    Pulkowo_, 1907); J. Larmor and E.H. Hills, "The irregular movement of
+    the Earth's axis of rotation: a contribution towards the analysis of
+    its causes" (_Monthly Notices R.A.S._, 1906, lxvii. 22); A.S.
+    Cristie, "The latitude variation Tide" (_Phil. Soc. of Wash._, 1895,
+    _Bull._ xiii. 103); H.G. van de Sande Bakhuysen, "Über die Änderung
+    der Polhöhe" (_Astr. Nachr._ No. 3261); A.V. Bäcklund, "Zur Frage
+    nach der Bewegung des Erdpoles" (_Astr. Nachr._ No. 3787); R.
+    Schumann, "Über die Polhöhenschwankung" (_Astr. Nachr._ No. 3873);
+    "Numerische Untersuchung" (_Ergänzungshefte zu den Astr. Nachr._ No.
+    11); _Weitere Untersuchungen_ (No. 4142); _Bull. astr._, 1900, June,
+    report of different theoretical memoirs.
+
+
+
+
+EARTH CURRENTS. After the invention of telegraphy it was soon found that
+telegraph lines in which the circuit is completed by the earth are
+traversed by natural electric currents which occasionally interfere
+seriously with their use, and which are known as "earth currents."
+
+1. Amongst the pioneers in investigating the subject were several English
+telegraphists, e.g. W.H. Barlow (1) and C.V. Walker (2), who were in
+charge respectively of the Midland and South-Eastern telegraph systems.
+Barlow noticed the existence of a more or less regular diurnal variation,
+and the result--confirmed by all subsequent investigators--that earth
+currents proper occur in a line only when both ends are earthed. Walker,
+as the result of general instructions issued to telegraph clerks,
+collected numerous statistics as to the phenomena during times of large
+earth currents. His results and those given by Barlow both indicate that
+the lines to suffer most from earth currents in England have the general
+direction N.E. to S.W. As Walker points out, it is the direction of the
+terminal plates relative to one another that is the essential thing. At
+the same time he noticed that whilst at any given instant the currents in
+parallel lines have with rare exceptions the same direction, some lines
+show normally stronger currents than others, and he suggested that
+differences in the geological structure of the intervening ground might
+be of importance. This is a point which seems still somewhat obscure.
+
+Our present knowledge of the subject owes much to practical men, but
+even in the early days of telegraphy the fact that telegraph systems are
+commercial undertakings, and cannot allow the public to wait the
+convenience of science, was a serious obstacle to their employment for
+research. Thus Walker feelingly says, when regretting his paucity of
+data during a notable earth current disturbance: "Our clerks were at
+their wits' end to clear off the telegrams.... At a time when
+observations would have been very highly acceptable they were too much
+occupied with their ordinary duties." Some valuable observations have,
+however, been made on long telegraph lines where special facilities have
+been given.
+
+Amongst these may be mentioned the observations on French lines in 1883
+described by E.E. Blavier (3), and those on two German lines
+Berlin-Thorn and Berlin-Dresden during 1884 to 1888 discussed by B.
+Weinstein (4).
+
+2. Of the experimental lines specially constructed perhaps the best
+known are the Greenwich lines instituted by Sir G.B. Airy (5), the lines
+at Pawlowsk due to H. Wild (6), and those at Parc Saint Maur, near Paris
+(7).
+
+_Experimental Lines._--At Greenwich observations were commenced in 1865,
+but there have been serious disturbances due to artificial currents from
+electric railways for many years. There are two lines, one to Dartford
+distant about 10 m., in a direction somewhat south of east, the other to
+Croydon distant about 8 m., in a direction west of south.
+
+Information from a single line is incomplete, and unless this is clearly
+understood erroneous ideas may be derived. The times at which the
+current is largest and least, or when it vanishes, in an east-west line,
+tell nothing directly as to the amplitude at the time of the resultant
+current. The lines laid down at Pawlowsk in 1883 lay nearly in and
+perpendicular to the geographical meridian, a distinct desideratum, but
+were only about 1 km. long. The installation at Parc Saint Maur,
+discussed by T. Moureaux, calls for fuller description. There are three
+lines, one having terminal earth plates 14.8 km. apart in the
+geographical meridian, a second having its earth plates due east and
+west of one another, also 14.8 km. apart, and the third forming a closed
+circuit wholly insulated from the ground. In each of the three lines is
+a Deprez d'Arsonval galvanometer. Light reflected from the galvanometer
+mirrors falls on photographic paper wound round a drum turned by
+clockwork, and a continuous record is thus obtained.
+
+3. Each galvanometer has a resistance of about 200 ohms, but is shunted
+by a resistance of only 2 ohms. The total effective resistances in the
+N.-S. and E.-W. lines are 225 and 348 ohms respectively. If i is the
+current recorded, L, g and s the resistances of the line, galvanometer
+and shunt respectively, then E, the difference of potential between the
+two earth plates, is given by
+
+  E = i(1 + g/s) {L + gs/(g + s)}.
+
+To calibrate the record, a Daniell cell is put in a circuit including
+1000 ohms and the three galvanometers as shunted. If i' be the current
+recorded, e the E.M.F. of the cell, then e = i'(1 + g/s){1000 + 3gs/(g +
+s)}. Under the conditions at Parc Saint Maur we may write 2 for gs/(g +
+s), and 1.072 for e, and thence we have approximately E = 0.240(i/i')
+for the N.-S. line, and E = -0.371(i/i') for the E.-W. line.
+
+The method of standardization assumes a potential difference between
+earth plates which varies slowly enough to produce a practically steady
+current. There are several causes producing currents in a telegraph wire
+which do not satisfy this limitation. During thunderstorms surgings may
+arise, at least in overhead wires, without these being actually struck.
+Again, if the circuit includes a variable magnetic field, electric
+currents will be produced independently of any direct source of
+potential difference. In the third circuit at Parc Saint Maur, where no
+earth plates exist, the current must be mainly due to changes in the
+earth's vertical magnetic field, with superposed disturbances due to
+atmospheric electricity or aerial waves. Even in the other circuits,
+magnetic and atmospheric influences play some part, and when their
+contribution is important, the galvanometer deflection has an uncertain
+value. What a galvanometer records when traversed by a suddenly varying
+current depends on other things than its mere resistance.
+
+Even when the current is fairly steady, its exact significance is not
+easily stated. In the first place there is usually an appreciable E.M.F.
+between a plate and the earth in contact with it, and this E.M.F. may
+vary with the temperature and the dryness of the soil. Naturally one
+employs similar plates buried to the same depth at the two ends, but
+absolute identity and invariability of conditions can hardly be secured.
+In some cases, in short lines (8), there is reason to fear that plate
+E.M.F.'s have been responsible for a good deal that has been ascribed to
+true earth currents. With deep earth plates, in dry ground, this source
+of uncertainty can, however, enter but little into the diurnal
+inequality.
+
+4. Another difficulty is the question of the resistance in the earth
+itself. A given E.M.F. between plates 10 m. apart may mean very
+different currents travelling through the earth, according to the
+chemical constitution and condition of the surface strata.
+
+According to Professor A. Schuster (9), if [rho] and [rho]' be the
+specific resistances of the material of the wire and of the soil, the
+current i which would pass along an underground cable formed of actual
+soil, equal in diameter to the wire connecting the plates, is given by i
+= i'[rho]/[rho]', where i' is the observed current in the wire. As
+[rho]' will vary with the depth, and be different at different places
+along the route, while discontinuities may arise from geological faults,
+water channels and so on, it is clear that even the most careful
+observations convey but a general idea as to the absolute intensity of
+the currents in the earth itself. In Schuster's formula, as in the
+formulae deduced for Parc Saint Maur, it is regarded as immaterial
+whether the wire connecting the plates is above or below ground. This
+view is in accordance with records obtained by Blavier (3) from two
+lines between Paris and Nancy, the one an air line, the other
+underground.
+
+5. The earliest quantitative results for the regular diurnal changes in
+earth currents are probably those deduced by Airy (5) from the records
+at Greenwich between 1865 and 1867. Airy resolved the observed currents
+from the two Greenwich lines in and perpendicular to the _magnetic_
+meridian (then about 21° to the west of astronomical north). The
+information given by Airy as to the precise meaning of the quantities he
+terms "magnetic tendency" to north and to west is somewhat scanty, but
+we are unlikely to be much wrong in accepting his figures as
+proportional to the earth currents from magnetic east to west and from
+magnetic north to south respectively. Airy gives mean hourly values for
+each month of the year. The corresponding mean diurnal inequality for
+the whole year appears in Table 1., the unit being arbitrary. In every
+month the algebraic mean of the 24 hourly values represented a current
+from north to south in the magnetic meridian, and from east to west in
+the perpendicular direction; in the same arbitrary units used in Table
+I. the mean values of these two "constant" currents were respectively
+777 and 559.
+
+6. _Diurnal Variation._--Probably the most complete records of diurnal
+variation are those discussed by Weinstein (4), which depend on several
+years' records on lines from Berlin to Dresden and to Thorn. Relative to
+Berlin the geographical co-ordinates of the other two places are:
+
+  Thorn       0° 29' N. lat. 5° 12' E. long.
+  Dresden     1° 28' S. lat. 0° 21' E. long.
+
+Thus the Berlin-Dresden line was directed about 8½° east of south, and
+the Berlin-Thorn line somewhat more to the north of east. The latter
+line had a length about 2.18 times that of the former. The resistances
+in the two lines were made the same, so if we suppose the difference of
+potential between earth plates along a given direction to vary as their
+distance apart, the current observed in the Thorn-Berlin line has to be
+divided by 2.18 to be comparable with the other. In this way, resolving
+along and perpendicular to the geographical meridian, Weinstein gives as
+proportional to the earth currents from east to west and from south to
+north respectively
+
+  J = 0.147i' + 0.435i, and J' = 0.989i' - 0.100i,
+
+where i and i' are the observed currents in the Thorn-Berlin and
+Dresden-Berlin lines respectively, both being counted positive when
+flowing towards Berlin.
+
+It is tacitly assumed that the average earth conductivity is the same
+between Berlin and Thorn as between Berlin and Dresden. It should also
+be noticed that local time at Berlin and Thorn differs by fully 20
+minutes, while the crests of the diurnal variations in _short_ lines at
+the two places would probably occur about the same local time. The
+result is probably a less sharp occurrence of maxima and minima, and a
+relatively smaller range, than in a short line having the same
+orientation.
+
+  TABLE I.
+
+  +-----------------------------------------------------+------------------------------+
+  |       Mean Diurnal Inequalities for the year.       |Numerical Values of resultant |
+  |                                                     |           current.           |
+  +----------------------+------------------------------+------------------------------+
+  |      Greenwich.      |     Thorn-Berlin-Dresden.    |    Thorn-Berlin-Dresden.     |
+  +--------+-------------+--------+-------+------+------+------------------------------+
+  |        |North | East | Berlin | Thorn |North | East |   Mean hourly values from    |
+  |  Hour. |  to  |  to  |   to   |  to   |  to  |  to  +-----+-------+--------+-------+
+  |        |South | West |Dresden.|Berlin.|South | West |Year.|Winter.|Equinox.|Summer.|
+  |        |(Mag.)|(Mag.)|        |       |(Ast.)|(Ast.)|     |       |        |       |
+  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
+  |    1   |  -94 |  -41 |   -17  |  -13  |  -20 |  -10 |  81 |   94  |    51  |   98  |
+  |    2   |  -68 |  -24 |    -6  |  -13  |   -9 |  -11 |  84 |  115  |    39  |   97  |
+  |    3   |  -44 |   -8 |    -1  |   -1  |   -1 |   -1 |  84 |  113  |    31  |  108  |
+  |    4   |  -18 |   +9 |   -20  |  +15  |  -17 |  +17 | 101 |   94  |    58  |  127  |
+  |    5   |  -30 |   -1 |   -79  |  +21  |  -74 |  +32 | 122 |   58  |    78  |  230  |
+  |    6   |  -63 |  -33 |  -139  |   +5  | -136 |  +26 | 148 |   80  |   139  |  225  |
+  |    7   | -121 |  -80 |  -138  |  -36  | -144 |  -14 | 166 |  155  |   206  |  136  |
+  |    8   | -175 | -123 |    -7  |  -98  |  -28 |  -92 | 203 |  152  |   185  |  271  |
+  |    9   | -156 | -137 |  +249  | -156  | +212 | -184 | 305 |   67  |   272  |  575  |
+  |   10   |  -43 |  -77 |  +540  | -184  | +494 | -254 | 557 |  232  |   628  |  811  |
+  |   11   |  +82 |   +1 |  +722  | -165  | +678 | -263 | 728 |  411  |   885  |  887  |
+  |  Noon  | +207 |  +66 |  +673  | -107  | +642 | -200 | 675 |  441  |   848  |  735  |
+  |    1   | +245 |  +94 |  +404  |  -20  | +395 |  -79 | 400 |  284  |   510  |  406  |
+  |    2   | +205 | +113 |   +35  |  +55  |  +46 |  +47 |  98 |   68  |   103  |  125  |
+  |    3   | +153 |  +97 |  -261  |  +99  | -237 | +132 | 272 |  136  |   355  |  324  |
+  |    4   | +159 | +108 |  -397  | +114  | -368 | +167 | 404 |  218  |   503  |  492  |
+  |    5   | +167 | +118 |  -391  | +108  | -363 | +160 | 397 |  206  |   453  |  532  |
+  |    6   | +125 |  +95 |  -311  |  +96  | -287 | +137 | 319 |  176  |   333  |  446  |
+  |    7   |  +43 |  +55 |  -237  |  +85  | -216 | +115 | 247 |  180  |   250  |  312  |
+  |    8   |  -22 |   +4 |  -191  |  +74  | -173 |  +98 | 201 |  207  |   217  |  181  |
+  |    9   | -115 |  -49 |  -168  |  +59  | -153 |  +81 | 174 |  208  |   194  |  120  |
+  |   10   | -138 |  -74 |  -135  |  +40  | -125 |  +58 | 138 |  155  |   149  |  111  |
+  |   11   | -136 |  -70 |   -84  |  +18  |  -79 |  +29 |  89 |   64  |    95  |  107  |
+  |Midnight| -147 |  -80 |   -43  |   -2  |  -43 |   +4 |  91 |   42  |   119  |  111  |
+  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
+
+It was found that the average current derived from a number of
+undisturbed days on either line might be regarded as made up of a
+"constant part" plus a regular diurnal inequality, the constant part
+representing the algebraic mean value of the 24 hourly readings. In both
+lines the constant part showed a decided alteration during the third
+year--changing sign in one line--in consequence, it is believed, of
+alterations made in the earth plates. The constant part was regarded as
+a plate effect, and was omitted from further consideration. Table I.
+shows in terms of an arbitrary unit--whose relation to that employed for
+Greenwich data is unknown--the diurnal inequality in the currents along
+the two lines, and the inequalities thence calculated for ideal lines in
+and perpendicular to the _geographical_ meridian. Currents are regarded
+as positive when directed from Berlin to Dresden and from north to
+south, the opposite point of view to that adopted by Weinstein. The
+table also shows the mean _numerical_ value of the resultant current
+(the "constant" part being omitted) for each hour of the day, for the
+year as a whole, and for winter (November to February), equinox (March,
+April, September, October) and summer (May to August). There is a marked
+double period in both the N.-S. and E.-W. currents. In both cases the
+numerically largest currents occur from 10 A.M. to noon, the directions
+then being from north to south and from west to east. The currents tend
+to die out and change sign about 2 P.M., the numerical magnitude then
+rising again rapidly to 4 or 5 P.M. The current in the meridian is
+notably the larger. The numerical values assigned to the resultant
+current are arithmetic means from the several months composing the
+season in question.
+
+7. The mean of the 24 hourly numerical values of the resultant current
+for each month of the year a deducible from Weinstein's data--the unit
+being the same as before--are given in Table II.
+
+  TABLE II.--_Mean Numerical Value of Resultant Current._
+
+  Jan.  Feb.  March  April  May  June  July  Aug.  Sep.  Oct.  Nov.  Dec.
+  152   211    293    328   313   314   337  300   258   235   165   132
+
+There is thus a conspicuous minimum at mid-winter, and but little
+difference between the monthly means from April to August. This is
+closely analogous to what is seen in the daily range of the magnetic
+elements in similar latitudes (see MAGNETISM, TERRESTRIAL). There is
+also considerable resemblance between the curve whose ordinates
+represent the diurnal inequality in the current passing from north to
+south, and the curve showing the hourly change in the westerly component
+of the horizontal magnetic force in similar European latitudes.
+
+8. _Relations with Sun-spots, Auroras and Magnetic Storms._--Weinstein
+gives curves representing the mean diurnal inequality for separate
+years. In both lines the diurnal amplitudes were notably smaller in the
+later years which were near sun-spot minimum. This raises a presumption
+that the regular diurnal earth currents, like the ranges of the magnetic
+elements, follow the 11-year sun-spot period. When we pass to the large
+and irregular earth currents, which are of practical interest in
+telegraphy, there is every reason to suppose that the sun-spot period
+applies. These currents are always accompanied by magnetic disturbances,
+and when specially striking by brilliant aurora. One most conspicuous
+example of this occurred in the end of August and beginning of September
+1859. The magnetic disturbances recorded were of almost unexampled size
+and rapidity, the accompanying aurora was extraordinarily brilliant, and
+E.M.F.'s of 700 and 800 volts are said to have been reached on telegraph
+lines 500 to 600 km. long. It is doubtful whether the disturbances of
+1859 have been equalled since, but earth current voltages of the order
+of 0.5 volts per mile have been recorded by various authorities, e.g.
+Sir W.H. Preece (10).
+
+It was the practice for several years to publish in the _Ann. du bureau
+central météorologique_ synchronous magnetic and earth current curves
+from Parc Saint Maur corresponding to the chief disturbances of the
+year. In most cases there is a marked similarity between the curve of
+magnetic declination and that of the north-south earth current. At times
+there is also a distinct resemblance between the horizontal force
+magnetic curve and that of the east-west earth current, but exceptions
+to this are not infrequent. Similar phenomena appear in synchronous
+Greenwich records published by Airy in 1868; these show a close
+accordance between the horizontal force curves and those of the currents
+from magnetic east to west. Originally it was supposed by Airy that
+whilst rapid movements in the declination and north-south current curves
+sometimes occurred simultaneously, there was a distinct tendency for
+the latter to precede the former. More recent examinations of the
+Greenwich records by W. Ellis (11), and of the Parc St Maur curves by
+Moureaux, have not confirmed this result, and it is now believed that
+the two phenomena are practically simultaneous.
+
+There has also been a conflict of views as to the connexion between
+magnetic and earth current disturbances. Airy's observations tended to
+suggest that the earth current was the primary cause, and the magnetic
+disturbance in considerable part at least its effect. Others, on the
+contrary, have supposed earth currents to be a direct effect of changes
+in the earth's magnetic field. The prevailing view now is that both the
+magnetic and the earth current disturbances are due to electric currents
+in the upper atmosphere, these upper currents becoming visible at times
+as aurora.
+
+9. There seems some evidence that earth currents can be called into
+existence by purely local causes, notably difference of level. Thus K.A.
+Brander (12) has observed a current flowing constantly for a good many
+days from Airolo (height 1160 metres) to the Hospice St Gotthard (height
+2094 metres). In an 8-km. line from Resina to the top of Vesuvius L.
+Palmieri (13)--observing in 1889 at three-hour intervals from 9 A.M. to
+9 P.M.--always found a current running uphill so long as the mountain
+was quiet. On a long line from Vienna to Graz A. Baumgartner (14) found
+that the current generally flowed from both ends towards intervening
+higher ground during the day, but in the opposite directions at night.
+During a fortnight in September and October 1885 hourly readings were
+taken of the current in the telegraph cable from Fort-William to Ben
+Nevis Observatory, and the results were discussed by H.N. Dickson (15),
+who found a marked preponderance of currents up the line to the summit.
+The recorded mean data, otherwise regarded, represent a "constant"
+current, equal to 29 in the arbitrary units employed by Dickson, flowing
+up the line, together with the following diurnal inequality, + denoting
+current towards Fort-William (i.e. down the hill, and nearly east to
+west).
+
+  Hour |  1  |  2  |  3  |  4  |  5  | 6  |  7  |  8  |   9 |  10 |  11 |  12 |
+       |     |     |     |     |     |    |     |     |     |     |     |     |
+  A.M. | -21 | -41 | +13 | +23 | +55 | -3 | +25 | -32 | -59 | -62 | -46 |  +6 |
+  P.M. | +24 | +18 |+115 | +18 | +75 | -5 | +50 |  -9 | -56 | -37 | -28 | -34 |
+
+There is thus a diurnal inequality, which is by no means very irregular
+considering the limited number of days, and it bears at least a general
+resemblance to that shown by Weinstein's figures for an east-west line
+in Germany. This will serve to illustrate the uncertainties affecting
+these and analogous observations. A constant current in one direction
+may arise in whole or part from plate E.M.F.'s; a current showing a
+diurnal inequality will naturally arise between _any_ two places some
+distance apart whether they be at different levels or not. Finally, when
+records are taken only for a short time, doubts must arise as to the
+generality of the results. During the Ben Nevis observations, for
+instance, we are told that the summit was almost constantly enveloped in
+fog or mist. By having three earth plates in the same vertical plane,
+one at the top of a mountain, the others at opposite sides of it, and
+then observing the currents between the summit and each of the base
+stations, as well as directly between the base stations--during an
+adequate number of days representative of different seasons of the year
+and different climatic conditions--many uncertainties would soon be
+removed.
+
+10. _Artificial Currents._--The great extension in the applications of
+electricity to lighting, traction and power transmission, characteristic
+of the end of the 19th century, has led to the existence of large
+artificial earth currents, which exert a disturbing influence on
+galvanometers and magnetic instruments, and also tend to destroy metal
+pipes. In the former case, whilst the disturbance is generally loosely
+assigned to stray or "vagabond" earth currents, this is only partly
+correct. The currents used for traction are large, and even if there
+were a perfectly insulated return there would be a considerable
+resultant magnetic field at distances from the track which were not
+largely in excess of the distance apart of the direct and return
+currents (16). At a distance of half a mile or more from an electric
+tram line the disturbance is usually largest in magnetographs recording
+the vertical component of the earth's field. The magnets are slightly
+displaced from the position they would occupy if undisturbed, and are
+kept in continuous oscillation whilst the trams are running (17). The
+extent of the oscillation depends on the damping of the magnets.
+
+The distance from an electric tram line where the disturbance ceases to
+be felt varies with the system adopted. It also depends on the length of
+the line and its subdivision into sections, on the strength of the
+currents supplied, the amount of leakage, the absence or presence of
+"boosters," and finally on the sensitiveness of the magnetic
+instruments. At the U.S. Coast and Geodetic Survey's observatory at
+Cheltenham the effect of the Washington electric trams has been detected
+by highly sensitive magnetographs, though the nearest point of the line
+is 12 m. away (18). Amongst the magnetic observatories which have
+suffered severely from this cause are those at Toronto, Washington
+(Naval Observatory), Kew, Paris (Parc St Maur), Perpignan, Nice, Lisbon,
+Vienna, Rome, Bombay (Colaba) and Batavia. In some cases magnetic
+observations have been wholly suspended, in others new observatories
+have been built on more remote sites.
+
+As regards damage to underground pipes, mainly gas and water pipes,
+numerous observations have been made, especially in Germany and the
+United States. When electric tramways have uninsulated returns, and the
+potential of the rails is allowed to differ considerably from that of
+the earth, very considerable currents are found in neighbouring pipes.
+Under these conditions, if the joints between contiguous pipes forming a
+main present appreciable resistance, whilst the surrounding earth
+through moisture or any other cause is a fair conductor, current passes
+locally from the pipes to the earth causing electrolytic corrosion of
+the pipes. Owing to the diversity of interests concerned, the extent of
+the damage thus caused has been very variously estimated. In some
+instances it has been so considerable as to be the alleged cause of the
+ultimate failure of water pipes to stand the pressure they are exposed
+to.
+
+  BIBLIOGRAPHY.--See Svante August Arrhenius, _Lehrbuch der kosmischen
+  Physik_ (Leipzig, 1903), pp. 984-990. For lists of references see J.E.
+  Burbank, _Terrestrial Magnetism_, vol. 10 (1905), p. 23, and P.
+  Bachmetjew (8). For papers descriptive of corrosion of pipes, &c., by
+  artificial currents see _Science Abstracts_ (in recent years in the
+  volumes devoted to engineering) under the heading "Traction, Electric;
+  Electrolysis." The following are the references in the text:--(1)
+  _Phil. Trans. R.S._ for 1849, pt. i. p. 61; (2) _Phil. Trans. R.S._
+  vol. 151 (1861), p. 89, and vol. 152 (1862), p. 203; (3) _Étude des
+  courants telluriques_ (Paris, 1884); (4) _Die Erdströme im deutschen
+  Reichstelegraphengebiet_ (Braunschweig, 1900); (5) _Phil. Trans. R.S._
+  vol. 158 (1868), p. 465, and vol. 160 (1870), p. 215; (6) _Mém. de
+  l'Académie St-Pétersbourg_, t. 31, No. 12 (1883); (7) T. Moureaux,
+  _Ann. du Bureau Central Mét._ (Année 1893), 1 Mem. p. B 23; (8) P.
+  Bachmetjew, _Mém. de l'Académie St-Pétersbourg_, vol. 12, No. 3
+  (1901); (9) _Terrestrial Magnetism_, vol. 3 (1898), p. 130; (10)
+  _Journal Tel. Engineers_ (1881); (11) _Proc. R.S._ vol. 52 (1892), p.
+  191; (12) _Akad. Abhandlung_ (Helsingfors, 1888); (13) _Acad. Napoli
+  Rend._ (1890), and _Atti_ (1894, 1895); (14) _Pogg. Ann._ vol. 76, p.
+  135; (15) _Proc. R.S.E._ vol. 13, p. 530; (16) A. Rücker, _Phil. Mag._
+  1 (1901), p. 423, and R.T. Glazebrook, ibid. p. 432; (17) J. Edler,
+  _Elektrotech. Zeit._ vol. 20 (1899); (18) L.A. Bauer, _Terrestrial
+  Magnetism_, vol. 11 (1906), p. 53.     (C. Ch.)
+
+
+
+
+EARTH-NUT, the English name for a plant known botanically as _Conopodium
+denudatum_ (or _Bunium flexuosum_), a member of the natural order
+Umbelliferae, which has a brown tuber-like root-stock the size of a
+chestnut. It grows in woods and fields, has a slender flexuous smooth
+stem 2 to 3 ft. high, much-divided leaves, and small white flowers in
+many-rayed terminal compound umbels. Boswell Syme, in _English Botany_,
+iv. 114, says: "The common names of this plant in England are various.
+It is known as earth-nut, pig-nut, ar-nut, kipper-nut, hawk-nut,
+jar-nut, earth-chestnut and ground-nut. Though really excellent in taste
+and unobjectionable as food, it is disregarded in England by all but
+pigs and children, both of whom appreciate it and seek eagerly for it."
+Dr Withering describes the roots as little inferior to chestnuts. In
+Holland and elsewhere on the continent of Europe they are more
+generally eaten.
+
+
+
+
+EARTH PILLAR, a pillar of soft rock, or earth, capped by some harder
+material that has protected it from denudation. The "bad lands" of
+western North America furnish numerous examples. Here "the formations
+are often beds of sandstone or shale alternating with unindurated beds
+of clay. A semi-arid climate where the precipitation is much
+concentrated seems to be most favourable to the development of this type
+of formation." The country round the Dead Sea, where loose friable sandy
+clay is capped by harder rock, produces "bad-land" topography. The cap
+of hard rock gives way at the joints, and the water making its way
+downwards washes away the softer material directly under the cracks,
+which become wider, leaving isolated columns of clay capped with hard
+sandstone or limestone. These become smaller and fewer as denudation
+proceeds, the pillars standing a great height at times, until finally
+they all disappear.
+
+
+
+
+EARTHQUAKE. Although the terrible effects which often accompany
+earthquakes have in all ages forced themselves upon the attention of
+man, the exact investigation of seismic phenomena dates only from the
+middle of the 19th century. A new science has been thus established
+under the name of _seismology_ (Gr. [Greek: seismos], an earthquake).
+
+_History._--Accounts of earthquakes are to be found scattered through
+the writings of many ancient authors, but they are, for the most part,
+of little value to the seismologist. There is a natural tendency to
+exaggeration in describing such phenomena, sometimes indeed to the
+extent of importing a supernatural element into the description. It is
+true that attempts were made by some ancient writers on natural
+philosophy to offer a rational explanation of earthquake phenomena, but
+the hypotheses which their explanations involved are, as a rule, too
+fanciful to be worth reproducing at the present day. It is therefore
+unnecessary to dwell upon the references to seismic phenomena which have
+come down to us in the writings of such historians and philosophers as
+Thucydides, Aristotle and Strabo, Seneca, Livy and Pliny. Nor is much to
+be gleaned from the pages of medieval and later writers on earthquakes,
+of whom the most notable are Fromondi (1527), Maggio (1571) and
+Travagini (1679). In England, the earliest work worthy of mention is
+Robert Hooke's _Discourse on Earthquakes_, written in 1668, and read at
+a later date before the Royal Society. This discourse, though containing
+many passages of considerable merit, tended but little to a correct
+interpretation of the phenomena in question. Equally unsatisfactory were
+the attempts of Joseph Priestley and some other scientific writers of
+the 18th century to connect the cause of earthquakes with electrical
+phenomena. The great earthquake of Lisbon in 1755 led the Rev. John
+Michell, professor of mineralogy at Cambridge, to turn his attention to
+the subject; and in 1760 he published in the _Philosophical
+Transactions_ a remarkable essay on the Cause and Phenomena of
+Earthquakes. A suggestion of much scientific interest was made by Thomas
+Young, when in his _Lectures on Natural Philosophy_, published in 1807,
+he remarked that an earthquake "is probably propagated through the earth
+nearly in the same manner as a noise is conveyed through the air." The
+recognition of the fact that the seismologist has to deal with the
+investigation of wave-motion in solids lies at the very base of his
+science. In 1846 Robert Mallet communicated to the Royal Irish Academy
+his first paper "On the Dynamics of Earthquakes"; and in the following
+year W. Hopkins, of Cambridge, presented to the British Association a
+valuable report in which earthquake phenomena were discussed in some
+detail. Mallet's labours were continued for many years chiefly in the
+form of Reports to the British Association, and culminated in his great
+work on the Neapolitan earthquake of 1857. An entirely new impetus,
+however, was given to the study of earthquakes by an energetic body of
+observers in Japan, who commenced their investigations about the year
+1880, mainly through the influence of Prof. John Milne, then of Tokyo.
+Their work, carried on by means of new instruments of precision, and
+since taken up by observers in many parts of the world, has so extended
+our knowledge of earthquake-motion that seismology has now become
+practically a new department of physical science.
+
+It is hardly too much to say, however, that the earliest systematic
+application of scientific principles to the study of the effects of an
+earthquake was made by Mallet in his investigation of the Neapolitan
+earthquake mentioned above. It is true, the great Calabrian earthquake
+of 1783 had been the subject of careful inquiry by the Royal Academy of
+Naples, as also by Deodat Dolomieu and some other scientific
+authorities; but in consequence of the misconception which at that time
+prevailed with regard to the nature of seismic activity, the results of
+the inquiry, though in many ways interesting, were of very limited
+scientific value. It was reserved for Mallet to undertake for the first
+time an extensive series of systematic observations in an area of great
+seismic disturbance, with the view of explaining the phenomena by the
+application of the laws of wave-motion.
+
+
+  Neapolitan earthquake, 1857.
+
+The "Great Neapolitan Earthquake," by which more than 12,300 lives were
+lost, was felt in greater or less degree over all Italy south of the
+parallel of 42°, and has been regarded as ranking third in order of
+severity among the recorded earthquakes of Europe. The principal shock
+occurred at about 10 P.M. on the 16th of December 1857; but, as is
+usually the case, it had been preceded by minor disturbances and was
+followed by numerous after-shocks which continued for many months. Early
+in 1858, aided by a grant from the Royal Society, Mallet visited the
+devastated districts, and spent more than two months in studying the
+effects of the catastrophe, especially examining, with the eye of an
+engineer, the cracks and ruins of the buildings. His voluminous report
+was published in 1862, and though his methods of research and his
+deductions have in many cases been superseded by the advance of
+knowledge, the report still remains a memorable work in the history of
+seismology.
+
+Much of Mallet's labour was directed to the determination of the
+position and magnitude of the subterranean source from which the
+vibratory impulses originated. This is known variously as the _seismic
+centre_, _centrum_, _hypocentre_, _origin_ or _focus_. It is often
+convenient to regard this centre theoretically as a point, but
+practically it must be a locus or space of three dimensions, which in
+different cases varies much in size and shape, and may be of great
+magnitude. That part of the surface of the earth which is vertically
+above the centre is called the _epicentre_; or, if of considerable area,
+the epicentral or epifocal tract. A vertical line joining the epicentre
+and the focus was termed by Mallet the _seismic vertical_. He calculated
+that in the case of the Neapolitan earthquake the focal cavity was a
+curved lamelliform fissure, having a length of about 10 m. and a height
+of about 3½ m., whilst its width was inconsiderable. The central point
+of this fissure, the theoretical seismic centre, he estimated to have
+been at a depth of about 6½ m. from the surface. Dr C. Davison, in
+discussing Mallet's data, was led to the conclusion that there were two
+distinct foci, possibly situated on a fault, or plane of dislocation,
+running in a north-west and south-east direction. Mallet located his
+epicentre near the village of Caggiano, not far from Polla, while the
+other seems to have been in the neighbourhood of Montemurro, about 25 m.
+to the south-east.
+
+The intensity, or violence, of an earthquake is greatest in or near the
+epicentre, whence it decreases in all directions. A line drawn through
+points of equal intensity forms a curve round the epicentre known as an
+_isoseist_, an _isoseismal_ or an _isoseismic line_. If the intensity
+declined equally in all directions the isoseismals would be circles, but
+as this is rarely if ever the case in nature they usually become
+ellipses and other closed curves. The tract which is most violently
+shaken was termed by Mallet the _meizoseismic area_, whilst the line of
+maximum destruction is known as the _meizoseismic line_. That isoseismal
+along which the decline of energy is most rapid was called by K. von
+Seebach a _pleistoseist_.
+
+In order to determine the position of the seismic centre, Mallet made
+much use of the cracks in damaged buildings, especially in walls of
+masonry, holding that the direction of such fractures must generally be
+at right angles to that in which the normal earthquake-wave reached
+them. In this way he obtained the "angle of emergence" of the wave. He
+also assumed that free-falling bodies would be overthrown and projected
+in the direction of propagation of the wave, so that the epicentre might
+immediately be found from the intersection of such directions. These
+data are, however, subject to much error, especially through want of
+homogeneity in the rocks, but Mallet's work was still of great value.
+
+
+  Charleston earthquake, 1886.
+
+A different method of ascertaining the depth of the focus was adopted by
+Major C.E. Dutton in his investigation of the Charleston earthquake of
+the 31st of August 1886 for the U.S. Geological Survey. This catastrophe
+was heralded by shocks of greater or less severity a few days previously
+at Summerville, a village 22 m. north-west of Charleston. The great
+earthquake occurred at 9.51 P.M., standard time of the 75th meridian,
+and in about 70 seconds almost every building in Charleston was more or
+less seriously damaged, while many lives were lost. The epicentral tract
+was mainly a forest region with but few buildings, and the principal
+records of seismological value were afforded by the lines of railway
+which traversed the disturbed area. In many places these rails were
+flexured and dislocated. Numerous fissures opened in the ground, and
+many of these discharged water, mixed sometimes with sand and silt,
+which was thrown up in jets rising in some cases to a height of 20 ft.
+Two epicentres were recognized--one near Woodstock station on the South
+Carolina railway, and the other, being the centre of a much smaller
+tract, about 14 m. south-west of the first and near the station of
+Rantowles on the Charleston and Savannah line. Around these centres and
+far away isoseismal lines were drawn, the relative intensity at
+different places being roughly estimated by the effects of the
+catastrophe on various structures and natural objects, or, where visible
+records were wanting, by personal evidence, which is often vague and
+variable. The Rossi-Forel scale was adopted. This is an arbitrary scale
+formulated by Professor M.S. de Rossi, of Rome, and Dr F.A. Forel, of
+Geneva, based mostly on the ordinary phenomena observed during an
+earthquake, and consisting of ten degrees, of which the lowest is the
+feeblest, viz. I. Microseismic shock; II. Extremely feeble shock; III.
+Very feeble shock; IV. Feeble; V. Shock of moderate intensity; VI.
+Fairly strong shock; VII. Strong shock; VIII. Very strong shock; IX.
+Extremely strong shock; X. Shock of extreme intensity. Other
+conventional scales, some being less detailed, have been drawn up by
+observers in such earthquake-shaken countries as Italy and Japan. A
+curve, or theoretical isoseismal, drawn through certain points where the
+decline of intensity on receding from the epicentre seems to be greatest
+was called by Dutton an "index-circle"; and it can be shown that the
+radius of such a circle multiplied by the square root of 3 gives the
+focal depth theoretically. In this way it was computed that in the
+Charleston earthquake the origin under Woodstock must have had a depth
+of about 12 m. and that near Rantowles a depth of nearly 8 m. The
+determination of the index-circle presents much difficulty, and the
+conclusions must be regarded as only approximate.
+
+It is probable, according to R.D. Oldham, that local earthquakes may
+originate in the "outer skin" of the earth, whilst a large world-shaking
+earthquake takes its origin in the deeper part of the "crust," whence
+such a disturbance is termed a _bathyseism_. Large earthquakes may have
+very extended origins, with no definite centre, or with several foci.
+
+
+  Great Indian earthquake, 1897.
+
+The gigantic disaster known as the "Great Indian Earthquake," which
+occurred on the 12th of June 1897, was the subject of careful
+investigation by the Geological Survey of India and was described in
+detail by the superintendent, R.D. Oldham. It is sometimes termed the
+Assam earthquake, since it was in that province that the effects were
+most severe, but the shocks were felt over a large part of India, and
+indeed far beyond its boundaries. Much of the area which suffered most
+disturbance was a wild country, sparsely populated, with but few
+buildings of brick or stone from which the violence of the shocks could
+be estimated. The epicentral tract was of great size, having an
+estimated area of about 6000 sq. m., but the mischief was most severe in
+the neighbourhood of Shillong, where the stonework of bridges, churches
+and other buildings was absolutely levelled to the ground. After the
+main disturbance, shocks of greater or less severity continued at
+intervals for many weeks. It is supposed that this earthquake was
+connected with movement of subterranean rock-masses of enormous
+magnitude along a great thrust-plane, or series of such planes, having a
+length of about 200 m. and a maximum breadth of not less than 50 m. It
+is pointed out by Oldham that this may be compared for size with the
+great Faille du Midi in Belgium, which is known to extend for a distance
+of 120 m. The depth of the principal focus, though not actually capable
+of determination, was probably less than 5 m. from the surface. From the
+focus many secondary faults and fractures proceeded, some reaching the
+surface of the ground. Enormous landslips accompanied the earthquake,
+and as an indirect effect of these slides the form of the water-courses
+became in certain cases modified. Permanent changes of level were also
+observed.
+
+
+  Kangra earthquake, 1905.
+
+Eight years after the great Assam earthquake India was visited by
+another earthquake, which, though less intense, resulted in the loss of
+about 20,000 lives. This catastrophe is known as the Kangra earthquake,
+since its centre seems to have been located in the Kangra valley, in the
+north-west Himalaya. It occurred on the 4th of April 1905, and the first
+great shocks were felt in the chief epifocal district at about 6.9 a.m.,
+Madras time. Although the tract chiefly affected was around Kangra and
+Dharmsala, there was a subordinate epifocal tract in Dehra Dun and the
+neighbourhood of Mussoorie, whilst the effects of the earthquake
+extended in slight measure to Lahore and other cities of the plain. It
+is estimated that the earthquake was felt over an area of about
+1,625,000 m. Immediately after the calamity a scientific examination of
+its effects was made by the Geological Survey of India, and a report was
+drawn up by the superintendent, C.S. Middlemiss.
+
+
+  California earthquake, 1906.
+
+The great earthquake, which, with the subsequent fire, wrought such
+terrible destruction in and around San Francisco on the 18th of April
+1906, was the most disastrous ever recorded in California. It occurred
+between 10 and 15 minutes after 5 A.M., standard time of the 120th
+meridian. The moment at which the disaster began and the duration of the
+shock varied at different localities in the great area over which the
+earthquake was felt. At San Francisco the main shock lasted rather more
+than one minute.
+
+According to the official Report, the earthquake was due to rupture and
+movement along the plane of the San Andreas fault, one of a series which
+runs for several hundred miles approximately in a N.W. and S.E.
+direction near the coast line. Evidence of fresh movement along this
+plane of dislocation was traced for a distance of 190 m. from San Juan
+on the south to Point Arena on the north. There the trace of the fault
+is lost beneath the sea, but either the same fault or another appears 75
+m. to the north at Point Delgada. The belt of disturbed country is
+notoriously unstable, and part of the fault had been known as the
+"earthquake crack." The direction is marked by lines of straight cliffs,
+long ponds and narrow depressions, forming a Rift, or old line of
+seismic disturbance. According to Dr G.K. Gilbert the earthquake zone
+has a length of 300 or 400 m. The principal displacement of rock, in
+1906, was horizontal, amounting generally to about 10 ft. (maximum 21
+ft.), but there was also locally a slight vertical movement, which
+towards the north end of the fault reached 3 ft. Movement was traced for
+a distance of about 270 m., and it is estimated that at least 175,000
+sq. m. of country must have been disturbed. In estimating the intensity
+of the earthquake in San Francisco a new scale was introduced by H.O.
+Wood. The greatest structural damage occurred on soft alluvial soil and
+"made ground." Most of the loss of property in San Francisco was due to
+the terrible fire which followed the earthquake and was beyond control
+owing to the destruction of the system of water-supply.
+
+Immediately after the catastrophe a California Earthquake Investigation
+Committee was appointed by the governor of the state; and the American
+Association for the Advancement of Science afterwards instituted a
+Seismological Committee. The elaborate Report of the State Investigation
+Committee, by the chairman, Professor A.C. Lawson, was published in
+1908.
+
+On the 17th of August 1906 a disastrous earthquake occurred at
+Valparaiso, and the year 1906 was marked generally by exceptional
+seismic activity.
+
+The Jamaica earthquake of the 14th of January 1907 appears to have
+accompanied movement of rock along an east and west fracture or series
+of fractures under the sea a few miles from the city of Kingston. The
+statue of Queen Victoria at Kingston was turned upon its pedestal the
+eighth of a revolution.
+
+
+  Messina earthquake, 1908.
+
+A terrible earthquake occurred in Calabria and Sicily on December 28,
+1908, practically destroying Messina and Reggio. According to the
+official returns the total loss of life was 77,283. Whilst the principal
+centre seems to have been in the Strait of Messina, whence the
+disturbance is generally known as the Messina earthquake, there were
+independent centres in the Calabrian peninsula, a country which had been
+visited by severe earthquakes not long previously, namely on September
+8, 1905, and October 23, 1907. The principal shock of the great Messina
+earthquake of 1908 occurred at 5.21 A.M. (4.21 Greenwich time), and had
+a duration of from 30 to 40 seconds. Neither during nor immediately
+before the catastrophe was there any special volcanic disturbance at
+Etna or at Stromboli, but it is believed that there must have been
+movement along a great plane of weakness in the neighbourhood of the
+Strait of Messina, which has been studied by E. Cortese. The sea-floor
+in the strait probably suffered great disturbance, resulting in the
+remarkable movement of water observed on the coast. At first the sea
+retired, and then a great wave rolled in, followed by others generally
+of decreasing amplitude, though at Catania the second was said to have
+been greater than the first. At Messina the height of the great wave was
+2.70 metres, whilst at Ali and Giardini it reached 8.40 metres and at
+San Alessio as much as 11.7 metres. At Malta the tide-gauge recorded a
+wave of 0.91 metre. The depth of the chief earthquake-centre was
+estimated by Dr E. Oddone at about 9 kilometres. The earthquake and
+accompanying phenomena were studied also by Professor A. Riccò, Dr M.
+Baratta and Professor G. Platania and by Dr F. Omori of Tokyo. After the
+great disturbance, shocks continued to affect the region intermittently
+for several months. In certain respects the earthquake of 1908 presented
+much resemblance to the great Calabrian catastrophe of 1783.
+
+It has been proposed by R.D. Oldham that the disturbance which causes
+the fracture and permanent displacement of the rocks during an
+earthquake should be called an "earthshake," leaving the term earthquake
+especially for the vibratory motion. The movement of the earthquake is
+molecular, whilst that of the earthshake is molar. Subsequently he
+suggested the terms _mochleusis_ and _orchesis_ ([Greek: mochleuô], I
+heave; [Greek: orcheomai], I dance), to denote respectively the molar
+and the molecular movement, retaining the word earthquake for use in its
+ordinary sense.
+
+In most earthquakes the proximate cause is generally regarded as the
+fracture and sudden movement of underground rock-masses. Disturbances of
+this type are known as "tectonic" earthquakes, since they are connected
+with the folding and faulting of the rocks of the earth's crust. They
+indicate a relief of the strain to which the rock-masses are subjected
+by mountain-making and other crustal movements, and they are
+consequently apt to occur along the steep face of a table-land or the
+margin of a continent with a great slope from land to sea. In many cases
+the immediate seat of the originating impulse is located beneath the
+sea, giving rise to submarine disturbances which have been called
+"seaquakes." Much attention has been given to these suboceanic
+disturbances by Professor E. Rudolph.
+
+Professor J.H. Jeans has pointed out that the regions of the earth's
+crust most affected by earthquakes lie on a great circle corresponding
+with the equator of the slightly pear-shaped figure that he assigns to
+the earth. This would represent a belt of weakness, subject to crushing,
+from the tendency of the pear to pass into a spherical or spheroidal
+form under the action of internal stresses. According to the comte de
+Montessus de Ballore, the regions of maximum seismic instability appear
+to be arranged on two great circles, inclined to each other at about
+67°. These are the Circumpacific and Mediterranean zones.
+
+Maps of the world, showing the origins of large earthquakes each year,
+accompany the Annual Reports of the Seismological Committee of the
+British Association, drawn up by Professor Milne. It is important to
+note that Professor Milne has shown a relationship between
+earthquake-frequency and the wandering of the earth's pole from its mean
+position. Earthquakes seem to have been most frequent when the
+displacement of the pole has been comparatively great, or when the
+change in the direction of movement has been marked. Valuable earthquake
+catalogues have been compiled at various times by Alexis Perrey, R. and
+J.W. Mallet, John Milne, T. Oldham, C.W.C. Fuchs, F. de Montessus de
+Ballore and others.
+
+
+  British earthquakes.
+
+Such earthquakes as are felt from time to time in Great Britain may
+generally be traced to the formation of faults, or rather to incidents
+in the growth of old faults. The East Anglian earthquake of the 22nd of
+April 1884--the most disastrous that had occurred in the British Isles
+for centuries--was investigated by Prof. R. Meldola and W. White on
+behalf of the Essex Field Club. The shocks probably proceeded from two
+foci--one near the villages of Peldon and Abberton, the other near
+Wivenhoe and Rowhedge, in N.E. Essex. It is believed that the
+superficial disturbance resulted from rupture of rocks along a deep
+fault. An attempt has been made by H. Darwin, for the Seismological
+Committee of the British Association, to detect and measure any gradual
+movement of the strata along a fault, by observation at the Ridgeway
+fault, near Upway, in Dorsetshire. Dr C. Davison in studying the
+earthquakes which have originated in Britain since 1889 finds that
+several have been "twins." A twin earthquake has two maxima of intensity
+proceeding from two foci, whereas a double earthquake has its successive
+impulses from what is practically a single focus. The Hereford
+earthquake of December 1896, which resulted in great structural damage,
+was a twin, having one epicentre near Hereford and the other near Ross.
+Davison refers it to a slip along a fault-plane between the anticlinal
+areas of Woolhope and May Hill; and according to the same authority the
+Inverness earthquake of the 18th of September 1901 was referable to
+movement along a fault between Loch Ness and Inverness. The South Wales
+earthquake of June 27, 1906, was probably due to movement connected with
+the Armorican system of folds, striking in an east and west direction.
+
+It may be noted that when a slip occurs along a fault, the displacement
+underground may be but slight and may die out before reaching the
+surface, so that no scarp is formed. In connexion, however, with a
+seismic disturbance of the first magnitude the superficial features may
+be markedly affected. Thus, the great Japan earthquake of October
+1891--known often as the Mino-Owari earthquake--was connected with the
+formation or development of a fault which, according to Professor B.
+Koto, was traced on the surface for a distance of nearly 50 m. and
+presented in places a scarp with a vertical throw of as much as 20 ft.,
+while probably the maximum displacement underground was very much
+greater.
+
+Although most earthquakes seem to be of tectonic type, there are some
+which are evidently connected, directly or indirectly, with volcanic
+activity (see VOLCANO). Such, it is commonly believed, were the
+earthquakes which disturbed the Isle of Ischia in 1881 and 1883, and
+were studied by Professor J. Johnston-Lavis and G. Mercalli. In addition
+to the tectonic and volcanic types, there are occasional earthquakes of
+minor importance which may be referred to the collapse of the roof of
+caverns, or other falls of rock in underground cavities at no great
+depth. According to Prof. T.J.J. See most earthquakes are due, directly
+or indirectly, to the explosive action of ste by the leakage of
+sea-water through the ocean floor.
+
+
+  Earthquake waves.
+
+Whatever the nature of the impulse which originates the earthquake, it
+gives rise to a series of waves which are propagated through the earth's
+substance and also superficially. In one kind, known as normal or
+condensational waves, or waves of elastic compression, the particles
+vibrate to and from the centre of disturbance, moving in the direction
+in which the wave travels, and therefore in a way analogous to the
+movement of air in a sound-wave. Associated with this type are other
+waves termed transverse waves, or waves of elastic distortion, in which
+the particles vibrate across or around the direction in which the wave
+is propagated. The normal waves result from a temporary change of volume
+in the medium; the transverse from a change of shape. The distance
+through which an earth-particle moves from its mean position of rest,
+whether radially or transversely, is called the amplitude of the wave;
+whilst the double amplitude, or total distance of movement, to and fro
+or up and down, like the distance from crest to trough of a water wave,
+may be regarded as the range of the wave. The period of a wave is the
+time required for the vibrating particle to complete an oscillation. As
+the rocks of the earth's crust are very heterogeneous, the
+earthquake-waves suffer refraction and reflection as they pass from one
+rock to another differing in density and elasticity. In this way the
+waves break up and become much modified in course of transmission, thus
+introducing great complexity into the phenomena. It is known that the
+normal waves travel more rapidly than the transverse.
+
+Measurements of the surface speed at which earthquake-waves travel
+require very accurate time-measurers, and these are not generally
+available in earthquake-shaken regions. Observations during the
+Charleston earthquake of 1886 were at that time of exceptional value,
+since they were made over a large area where standard time was kept.
+Lines drawn through places around the epicentre at which the shock
+arrives at the same moment are called coseismal lines. The motion of the
+wave is to be distinguished from the movement of the vibrating
+particles. The velocity of the earth-particle is its rate of movement,
+but this is constantly changing during the vibration, and the rate at
+which the velocity changes is technically called the acceleration of the
+particle.
+
+Unfelt movements of the ground are registered in the earthquake records,
+or seismograms, obtained by the delicate instruments used by modern
+seismologists. From the study of the records of a great earthquake from
+a distant source, sometimes termed a teleseismic disturbance, some
+interesting inferences have been drawn with respect to the constitution
+of the interior of the earth. The complete record shows two phases of
+"preliminary tremors" preceding the principal waves. It is believed that
+while the preliminary tremors pass through the body of the earth, the
+principal waves travel along or parallel to the surface. Probably the
+first phase represents condensational, and the second phase
+distortional, waves. Professor Milne concludes from the speed of the
+waves at different depths that materials having similar physical
+properties to those at the surface may extend to a depth of about 30 m.,
+below which they pass into a fairly homogeneous nucleus. From the
+different rates of propagation of the precursors it has been inferred by
+R.D. Oldham that below the outer crust, which is probably not everywhere
+of the same thickness, the earth is of practically uniform character to
+a depth of about six-tenths of the radius, but the remaining four-tenths
+may represent a core differing physically and perhaps chemically from
+the outer part. Oldham also suggests, from his study of oceanic and
+continental wave-paths, that there is probably a difference in the
+constitution of the earth beneath oceans and beneath continents.
+
+The surface waves, which are waves of great length and long period and
+are propagated to great distances with practically a constant velocity,
+have been regarded as quasi-elastic gravitational waves. Further, in a
+great earthquake the surface of the ground is sometimes visibly agitated
+in the epifocal district by undulations which may be responsible for
+severe superficial damage. (See also for elastic waves ELASTICITY, §
+89.)
+
+An old classification of earthquake-shocks, traces of which still linger
+in popular nomenclature, described them as "undulatory," when the
+movement of the ground was mainly in a horizontal direction;
+"subsultory," when the motion was vertical, like the effect of a normal
+wave at the epicentre; and "vorticose," when the movement was rotatory,
+apparently due to successive impulses in varying directions.
+
+The sounds which are associated with seismic phenomena, often described
+as subterranean rumbling and roaring, are not without scientific
+interest, and have been carefully studied by Davison. "Isacoustic lines"
+are curves drawn through places where the sound is heard by the same
+percentage of observers. The sound is always low and often inaudible to
+many.
+
+The refined instruments which are now used by seismologists for
+determining the elements of earthquake motion and for recording
+earthquakes from distant origins are described in the article
+SEISMOMETER. These instruments were developed as a consequence of the
+attention given in modern times to the study of earthquakes in the Far
+East.     (F. W. R.*)
+
+
+  Seismology in Japan.
+
+Strange as it may appear, the advances that have been made in the study
+of earthquakes and the world-wide interest shown in their phenomena were
+initiated in work commenced in Japan. When the Japanese government,
+desiring to adopt Western knowledge, invited to its shores bodies of men
+to act as its instructors, the attention of the newcomers was naturally
+attracted to the frequent shakings of the ground. Interest in these
+phenomena increased more rapidly than their frequency, and at length it
+was felt that something should be done for their systematic study. At
+midnight on the 22nd of February 1880 movements more violent than usual
+occurred; chimneys were shattered or rotated, tiles slid down from
+roofs, and in the morning it was seen that Yokohama had the appearance
+of a city that had suffered a bombardment. The excitement was intense,
+and before the ruins had been removed a meeting was convened and the
+Seismological Society of Japan established. The twenty volumes of
+original papers published by this body summarize to a large extent the
+results of the later study of seismology.[1]
+
+The attention of the students of earthquakes in Japan was at first
+directed almost entirely to seismometry or earthquake measurement. Forms
+of apparatus which then existed, as for example the seismographs,
+seismometers and seismoscopes of Mallet, Palmieri and others, were
+subjected to trial; but inasmuch as they did little more than indicate
+that an earthquake had taken place--the more elaborate forms recording
+also the time of its occurrence--they were rapidly discarded, and
+instruments were constructed to _measure_ earthquake motion. Slightly
+modified types of the new instruments devised in Japan were adopted
+throughout the Italian peninsula, and it is fair to say that the
+seismometry developed in Japan revolutionized the seismometry of the
+world. The records obtained from the new instruments increased our
+knowledge of the character of earthquake motion, and the engineer and
+the architect were placed in a position to construct so that the effects
+of known movements could be minimized. It was no doubt the marked
+success, both practical and scientific, attending these investigations
+that led the Japanese government to establish a chair of seismology at
+its university, to organize a system of nearly 1000 observing stations
+throughout the country, and in 1893 to appoint a committee of scientific
+and practical men to carry out investigations which might palliate the
+effects of seismic disturbances. In the first year this committee
+received a grant of £5000, and as liberal sums for the same purpose
+appear from time to time in the parliamentary estimates, it may be
+assumed that the work has been fraught with good results. In their
+publications we find not only records of experiences and experiments in
+Japan, but descriptions and comments upon earthquake effects in other
+countries. In two of the volumes there are long and extremely well
+illustrated accounts of the earthquake which on the 12th of June 1897
+devastated Assam, to which country two members of the above-mentioned
+committee were despatched to gather such information as might be of
+value to the architect and builder in earthquake-shaken districts.
+
+
+  Seismological research.
+
+A great impetus to seismological investigation in Europe and America was
+no doubt given by the realization of the fact that a large earthquake
+originating in any one part of the world may be recorded in almost any
+other. Italy for many years past has had its observatories for recording
+earthquakes which can be felt, and which are of local origin, but at the
+present time at all its first-class stations we find instruments to
+record the unfelt movements due to earthquakes originating at great
+distances, and as much attention is now paid to the large earthquakes of
+the world as to the smaller ones originating within Italian
+territory.[2] The _Kaiserliche Akademie der Wissenschaften_ of Vienna
+established earthquake observatories in Austria,[3] and the Central
+Observatorium of St Petersburg has carried out similar work in Russia.
+Germany attached a seismological observatory to its university at
+Strassburg, whilst provision has been made for a professorship of Earth
+Physics (_Geophysik_) at Göttingen.[4] In accordance with the
+recommendation of the British Association, seismographs of a similar
+character have been installed at stations all over the world.[5] The
+principal objects of this extended and still extending system of
+stations are to determine the velocity with which motion is propagated
+over the surface and through the interior of the earth, to locate the
+positions of sub-oceanic earthquake origins, and generally to extend our
+knowledge respecting the physical nature of the planet on which we live.
+
+
+  Frequency of earthquakes.
+
+We now know that earthquakes are many times more frequent than was
+previously supposed. In Japan, for example, between 1885 and 1892 no
+fewer than 8331 were recorded--that is to say, on the average there were
+during that time more than 1000 disturbances per year. Although many of
+these did not cause a sensible shaking over areas exceeding a few
+hundred square miles, many of them were sufficiently intense to
+propagate vibrations round and through the globe. If we pick out the
+well-marked earthquake districts of the world, and give to each of them
+a seismicity or earthquake frequency per unit area one-third of that in
+Japan, the conclusion arrived at is that considerable areas of our
+planet are on the average shaken every half-hour.
+
+
+  Volcanoes and earthquakes.
+
+The knowledge which we now possess respecting the localities where
+earthquakes are frequent and the forms of the foci from which they have
+spread, enables us to speak definitely respecting the originating causes
+of many of these phenomena. It is found, for example, that although in
+many countries there may be displays of volcanic and seismic activity
+taking place almost side by side, it is only rarely that there is direct
+relationship between the two. Now and then, however, before a volcano
+breaks into eruption there may be a few ineffectual efforts to form a
+vent, each of which is accompanied by no more than a slight local
+shaking of the ground. This is true even for the largest and most
+violent eruptions, when mountains have with practically a single effort
+blown off their heads and shoulders. Thus the earthquake which
+accompanied the eruption of Bandaisan, in central Japan, in 1888 was
+felt only over a radius of 25 m. The analyses of the seismic registers
+of Japan clearly indicate that comparatively few shakings originate near
+to the volcanoes of the country, the majority of them, like those of
+many other countries, coming from regions where volcanic rocks are
+absent. The greatest number spread inland from the Pacific seaboard, the
+movement becoming more and more feeble as it approaches the backbone of
+the country, which is drilled with numerous volcanic vents. What is true
+for Japan is generally true for the western coasts of North and South
+America.
+
+
+  Origin of earthquakes.
+
+Speaking broadly, earthquakes are most frequent along the steeper
+flexures in the earth's surface, and in those regions where there is
+geological evidence to show that slow secular movements in the earth's
+crust are possibly yet in progress. With a unit distance of 2 degrees,
+or 120 geographical m., we find that the slopes running eastwards from
+the highlands of Japan and westwards from the Andean ridges down into
+the Pacific vary from 1 in 20 to 1 in 30, and it is on the faces or near
+to the bottom of these slopes that seismic efforts are frequent. The
+slopes running from Australia, eastern America and western Europe into
+the neighbouring oceans vary between 1 in 70 and 1 in 250, and in these
+regions earthquakes are of rare occurrence. The seismic activity met
+with in the Himalayas and the Alps finds its best explanation in the
+fact that these mountains are geologically recent, and there are no
+reasons to doubt that the forces which brought their folds into
+existence are yet in action.
+
+This peculiar association of earthquakes with pronounced topographical
+configuration and certain geological conditions evidently indicates that
+the origin of many of them is connected with rock folding. Inasmuch as
+certain large earthquakes have been accompanied by rock fracture, as for
+example in 1891, when in central Japan a fault some 50 m. in length was
+created, whilst the origins of others have been distinctly traced to the
+line of an existing fault or its continuation, we may conclude that the
+majority of earthquakes are spasmodic accelerations in the secular
+movements which are creating (and in some instances possibly
+obliterating) the more prominent features of the earth's surface. These
+secular movements, which include upheavals, subsidences, horizontal
+displacements--all of which are explained on the assumption of a crust
+seeking support on a nucleus gradually contracting by loss of heat, are
+collectively referred to as bradyseismical ([Greek: bradys], slow)
+movements. To these may be added movements directly attributable to the
+influence of gravity. Sub-oceanic districts in a state of seismic strain
+may be so far loaded by the accumulation of sediments that gentle
+bending may be accompanied by sudden yieldings. This possibly accounts
+for the frequency of earthquakes off the mouth of the Tonegawa on the
+eastern side of Japan. The distortions so frequently observed in fossils
+and pebbles, the varying thickness of contorted strata, and the "creep"
+in coal-mines, together with other phenomena, indicate that rocks may
+flow. Observations of this nature lead to the supposition that high
+plateau-like regions may be gradually subsiding under the influence of
+their own weight, and that the process of settlement may from time to
+time be spasmodic in its character. Whether the earthquakes which
+originate round the submerged basal frontiers of the continents bounding
+the Pacific are ever attributable to such activities, it is impossible
+to say. All that we know with certainty is that they are sometimes
+accompanied by such a vast displacement of material that the ocean has
+been set into a state of oscillation for periods of 24 hours, that in
+some instances there have been marked changes in depth, and that
+enormous sub-oceanic landslips have occurred. These phenomena are,
+however, equally well explained on the assumption of sudden faulting
+accompanied by violent shaking, which would dislodge steeply inclined
+beds of material beneath the ocean as it does upon the land.
+
+
+  Two types of earthquake motion.
+
+Although the proximate cause of earthquake motion is traced to sudden
+yieldings in the crust of the earth brought about by some form of
+bradyseismical action, the existence of at least two distinct types of
+seismic motion indicates that the mechanical conditions accompanying the
+fracturing of rocks are not always identical. 90 or 95% of the
+earthquakes which can be recorded consist of elastic or quasi-elastic
+vibrations. The remainder, including the large earthquakes, not only
+exhibit the elastic movements, but are accompanied by surface
+undulations which are propagated most certainly for some hundreds of
+miles round their origin, and then as horizontal movements sweep over
+the whole surface of the globe. The former of these may accompany the
+formation of a new fault or the sudden renewal of movement along an old
+one; they are cracking or rending effects, without any great
+displacement. The latter are probably fracturings accompanied by
+vertical and horizontal displacements of masses of the earth's crust
+sufficiently great to set up the observed surface undulations. These
+shocks are so frequently followed a few minutes later by disturbances,
+which from their similarity to the movements which have preceded them
+may be called earthquake echoes, that we are led to the speculation that
+we are here dealing with the caving-in of ill-supported portions of the
+earth's crust, the waves from which are radiated to boundaries and then
+returned to their origin to coalesce and give rise to a second impulse
+not unlike the primary. Succeeding the first repetition of motion
+recorded by the seismograph there is often a rhythmical repetition of
+similar wave groups, suggesting the existence within our earth of
+phenomena akin to multiple echoes.
+
+
+  Character of earthquake motion.
+
+The introduction of new methods into seismometry quickly revolutionized
+our ideas respecting the character of earthquake motion. Although an
+earthquake may be strongly felt within a distance of 50 m. from its
+origin, and although the movements in the upper storeys of buildings
+within the shaken area may be large, the actual range of the horizontal
+motion of the ground is usually less than {1/10} of an inch. With such
+earthquakes ordinary seismographs for recording vertical motion do not
+show any disturbance. When the movement reaches ½ in. it becomes
+dangerous, and a back-and-forth movement of an inch is usually
+accompanied by destructive effects. In this latter case the amplitude of
+the vertical record which indicates the existence of surface waves will
+vary between ½ and {1/100} of an inch. In the earthquake which
+devastated central Japan on the 26th of October 1891, nearly every
+building within the epifocal district fell, the ground was fissured,
+forests slipped down from mountain sides to dam up valleys, whilst the
+valleys themselves were permanently compressed. The horizontal movements
+seem to have reached 9 in. or 1 ft., and the surface undulations were
+visible to the eye.
+
+
+  Period and duration.
+
+The rapidity with which the movements are performed varies throughout a
+disturbance. A typical earthquake usually commences with minute elastic
+vibrations, the periods of which vary between {1/5} and {1/20} of a
+second. These are recorded by seismographs, and are noticed by certain
+of the lower animals like pheasants, which before the occurrence of
+movement perceptible to human beings scream as if alarmed. When an
+earthquake is preceded by a sound we have evidence of preliminary
+tremors even more rapid than those recorded by seismographs. Following
+these precursors there is a shock or shocks, the period of which will be
+1 or 2 seconds. From this climax the movements, although irregular in
+character, become slower and smaller until finally they are
+imperceptible. The duration of a small earthquake usually varies from a
+few seconds to a minute, but large earthquakes, which are accompanied by
+surface undulations, may be felt for 2 or 3 minutes, whilst an ordinary
+seismograph indicates a duration of from 6 to 12 minutes. A free
+horizontal pendulum tells us that with severe earthquakes the ground
+comes to rest by a series of more or less rhythmical surgings,
+continuing over 1 or 2 hours. Although the maximum displacement has a
+definite direction, the successive vibrations are frequently performed
+in many different azimuths. The predominating direction at a given
+station in certain instances is apparently at right angles to the strike
+of the neighbouring strata, this being the direction of easiest
+yielding.
+
+
+  Velocity.
+
+Earthquake motion as recorded at stations several thousands of miles
+distant from its origin exhibits characteristics strikingly different
+from those just described. The precursors now show periods of from 1 to
+5 seconds, whilst the largest movements corresponding to the shocks may
+have periods of from 20 to 40 seconds. The interval of time by which the
+first tremors have outraced the maximum movement has also become
+greater. Within a few hundreds of miles from an origin this interval
+increases steadily, the velocity of propagation of the first movements
+being about 2 km. per second, whilst that of the latter may be taken at
+about 1.6 km. per second. Beyond this distance the velocity of
+transmission of the first movements rapidly increases, and for great
+distances, as for example from Japan to England, it is higher than we
+should expect for waves of compression passing through steel or glass.
+This observation precludes the idea that these preliminary tremors have
+travelled through the heterogeneous crust of the earth, and since the
+average velocity of their transmission increases with the length of the
+path along which they have travelled, and we but rarely obtain certain
+evidence that a seismograph has been disturbed by waves which have
+reached it by travelling in opposite directions round the world, we are
+led to the conclusion that earthquake precursors pass through our earth
+and not round its surface. The following table relating to earthquakes,
+which originated off the coast of Borneo on the 20th and 27th of
+September 1897, is illustrative of the velocities here considered:--
+
+  +---------------------------+-----------+-------------+---------------+
+  |                           |           |             |       _______ |
+  |                           | Distance  |  Velocity   |      /Average |
+  |        Localities         |   from    |   in kms.   |     /depth of |
+  |                           |  origin   | per sec. if |  \ / chord in |
+  |                           |in degrees.|  on chord.  | ¼ V  kms.     |
+  +---------------------------+-----------+-------------+---------------+
+  | Nicolaieff                |    81°    |     8.1     |      8.0      |
+  | Potsdam                   |    92°    |     8.4     |      9.1      |
+  | Catania, Ischia, Rocca di |           |             |               |
+  |   Papa, Rome              |    96°    |     9.0     |      9.5      |
+  | Isle of Wight             |   103°    |     9.8     |     10.2      |
+  +---------------------------+-----------+-------------+---------------+
+
+The chords referred to here are those joining the earthquake origins and
+distant observing stations, and it will be noted that one-quarter of the
+square root of the average depths at which these run closely corresponds
+to observed average velocities if wave paths followed chords. This
+increase of velocity with average depth shows that the paths followed
+through the earth must be curved with their convexity towards the centre
+of the earth. These observations do not directly tell us to what extent
+a true wave path is deflected from the direction of a chord, but they
+suggest as an extremely plausible assumption that the square of the
+speed is a linear function of the depth below the surface of the earth.
+With this assumption Dr C.G. Knott shows that the square of the speed
+(v²) can be expressed linearly in terms of the average depth of the
+chord d, thus: v² = 2.9 + .026 d, the units being miles and seconds. The
+formula applies with fair accuracy to moderate and high values of d, but
+it gives too high a value for short chords. It follows that the square
+of the speed increases 0.9% per mile of descent in the earth. The
+conclusion we arrive at is that the preliminary tremors which pass
+through the earth do so in the vicinity of their origin at the rate of
+almost 2.3 km. per second. This velocity increases as the wave path
+plunges downwards, attaining in the central regions a velocity of 16 to
+17 kms., whilst the highest average velocity which is across a diameter
+lies between 10 and 12 kms. per second.
+
+The large surface waves radiating from an origin to a distant place have
+velocities lying between 1.6 and 4 kms. per second, and it has been
+observed that when the higher velocity has been noted this refers to an
+observation at a station very remote from the origin. One explanation of
+this is the assumption that only very large waves indicating a large
+initial disturbance are capable of travelling to great distances, and as
+pointed out by R.D. Oldham, large waves under the influence of gravity
+will travel faster than small waves. These waves (which may be
+gravitational or distortional) are recorded as slow tiltings of the
+ground measured by angles of 0.5 to 10 or 15 seconds of arc, or as
+horizontal displacements of 0.5 or several millimetres. Their calculated
+lengths have reached 50 kms. (31 m.).
+
+
+  Frequency.
+
+In the section of this article relating to the cause of earthquakes a
+little has been said about their frequency or the number of times these
+phenomena are repeated during a given interval of time. It has been
+shown that all countries are very often moved by earthquakes which have
+originated at great distances. Great Britain, for example, is crossed
+about 100 times a year by earthquake waves having durations of from 3
+minutes to 3 hours, whilst the vibratory motions which originate in that
+country are not only small but of rare occurrence. In the earlier stages
+of the world's history, because the contraction of its nucleus was more
+rapid than it is at present, it is commonly inferred that phenomena
+accompanying bradyseismical activity must have been more pronounced and
+have shown themselves upon a grander scale than they do at the present
+time. Now, although the records of our rocks only carry us back over a
+certain portion of this history, they certainly represent an interval of
+time sufficiently long to furnish some evidence of such enfeeblement if
+it ever existed. So far from this being the case, however, we meet with
+distinct evidences in the later chapters of geological history of
+plutonic awakenings much more violent than those recorded at its
+commencement. During Palaeozoic times many mountain ranges were formed,
+and accompanying these orogenic processes there was marked volcanic
+activity. In the succeeding Secondary period plutonic forces were
+quiescent, but during the formation of the early Tertiaries, when some
+of the largest mountain ranges were created, they awoke with a vigour
+greater than had ever been previously exhibited. At this period it is
+not improbable that Scotland was as remarkable for its volcanoes and its
+earthquakes as Japan is at the present day. If the statement relating to
+the general decrease in bradyseismical changes referred merely to their
+frequency, and omitted reference to their magnitude, the views of the
+geologist and physicist might harmonize. One explanation for this
+divergence of opinion may rest on the fact that too little attention has
+been directed to all the conditions which accompany the adaptation of
+the earth's crust to its shrinking nucleus. As the latter grows smaller
+the puckerings and foldings of the former should grow larger. Each
+succeeding geological epoch should be characterized by mountain
+formations more stupendous than those which preceded them, whilst the
+fracturing, dislocation, caving-in of ill-supported regions, and
+creation of lines of freedom for the exhibition of volcanic activity
+which would accompany these changes, would grow in magnitude. The
+written records of many countries reflect but on a smaller scale the
+crystallized records in their hills. In 1844, at Comrie, in Perthshire,
+as many as twelve earthquakes were recorded in a single month, whilst
+now there are but one or two per year. Earthquake frequency varies with
+time. A district under the influence of hypogenic activities reaches a
+condition of seismic strain which usually is relieved rapidly at first,
+but subsequently more slowly.
+
+The small shocks which follow an initial large disturbance are known as
+after-shocks. The first shock which in 1891 devastated central Japan was
+accompanied by the formation of a large fault, and the 3364 small shocks
+which succeeded this during the following two years are regarded as due
+to intermittent settlements of disjointed material. The decreasing
+frequency with which after-shocks occur may be represented by a curve.
+Dr F. Omori points out that the continuation of such a curve gives the
+means of determining the length of time which will probably elapse
+before the region to which it refers will return to the same seismic
+quiescence that it had prior to the initial disturbance.
+
+
+  Periodicity.
+
+The positive results that we have respecting the periodicity of
+earthquakes are but few. Generally earthquakes are somewhat more
+frequent during winter than during summer, and this applies to both the
+northern and southern hemispheres. The annual periodicity, which,
+however, does not show itself if only destructive earthquakes are
+considered, finds an explanation, according to Dr Knott, in the annual
+periodicity of long-continued stresses, as for example those due to the
+accumulation of snow and to barometric gradients. For certain earthquake
+regions there appears to be a distinct semi-annual period for which no
+satisfactory explanation has yet been adduced. Although the elaborate
+registers of Japan, which have enabled us to group earthquakes according
+to their respective origins and varying intensities, and to separate
+after-shocks from initial disturbances, have been subjected by Dr Knott
+to most careful analysis, with the object of discovering periodicities
+connected with the ebb and flow of the tides, the lunar day or lunar
+months, nothing of marked character has been found. Certainly there is
+slight evidence of a periodicity connected with the times of conjunction
+and opposition of the sun and moon, and a maximum frequency near the
+time of perigee, but the effect of lunar stresses is comparatively
+insignificant. Ordinary earthquakes, and especially after-shocks, show a
+diurnal period, but we cannot say that there are more earthquakes during
+the night than during the day.
+
+
+  Magnetic phenomena.
+
+Many experiments and investigations have been made to determine a
+possible relationship between earthquakes and electrical phenomena, but
+beyond drawing attention to the fact that luminous appearances may
+accompany the friction of moving masses of rock, and that a temporary
+current may be established in a line by the disturbance of an
+earth-plate, these inquiries have yielded but little of importance. The
+inquiries respecting a possible relationship between adjustments so
+frequently taking place within and beneath that region called the crust
+of the earth and magnetic phenomena are, however, of a more promising
+nature. We have seen that at or near the origin of earthquakes which for
+several hours disturb continents, and occasionally cause oceans to
+oscillate for longer periods, we sometimes have direct evidence of the
+bodily displacement of many cubic miles of material. When this material
+is volcanic it is almost invariably magnetic, and we perceive in its
+sudden rearrangement causes which should produce magnetic effects within
+an epifocal district. In Japan, where attention is being directed to
+phenomena of this description, not only have such effects been observed,
+but unusual magnetic disturbances have been noted prior to the
+occurrence of large earthquakes. These may, of course, be regarded as
+mere coincidences, but when we consider volcanic and seismic activities
+as evidences of physical and chemical changes, together with mechanical
+displacements of a magnetic magma, it is reasonable to suppose that they
+should have at least a local influence upon magnetic needles. Another
+form of disturbance to which magnetic needles are subjected is that
+which accompanies the passage of large earth-waves beneath certain
+observatories situated at great distances from earthquake origins. At
+Utrecht, Potsdam and Wilhelmshaven the magnetographs are frequently
+disturbed by seismic waves, whilst at many other European observatories
+such effects are absent or only barely appreciable. To explain these
+marked differences in the behaviour of magnetic needles at different
+stations we are at present only in a position to formulate hypotheses.
+They may be due to the fact that different needles have different
+periodic times of oscillation; it is possible that at one observatory
+the mechanical movements of the ground are much greater than at others;
+we may speculate on the existence of materials beneath and around
+various observatories which are different in their magnetic characters;
+and, lastly, we may picture a crust of varying thickness, which from
+time to time is caused to rise and fall upon a magnetic magma, the
+places nearest to this being the most disturbed.
+
+
+  Effects on the human mind.
+
+A subject to which but little attention has been directed is the effect
+which displays of seismic and volcanic activities have had upon the
+human mind. The effects are distinctly dual and opposite in character.
+In countries like England, where earthquakes are seldom experienced, the
+prevailing idea is that they are associated with all that is baneful.
+For certain earthquakes, which fortunately are less than 1% of those
+which are annually recorded, this is partially true. A disastrous shock
+may unnerve a whole community. Effects of this nature, however, differ
+in a marked manner with different nationalities. After the shock of
+1891, when Japan lost 9960 of its inhabitants, amongst the wounded
+indications of mental excitement were shown in spinal and other trouble.
+Notwithstanding the lightheartedness of this particular nation, it is
+difficult to imagine that the long series of seismic effects chronicled
+in Japanese history, which culminated in 1896 in the loss of 29,000
+lives by sea-waves, has been without some effect upon its mental and
+moral character. Several earthquakes are annually commemorated by
+special services at temples. In bygone times governments have recognized
+earthquakes as visitations of an angry deity, whom they have endeavoured
+to appease by repealing stringent laws and taxes. In other countries the
+sermons which have been preached to show that the tremblings of the
+world were visitations consequent on impiety, and the prayers which have
+been formulated to ward off disasters in the future, far exceed in
+number the earthquakes which gave rise to them. In 1755 many of the
+English clergy held the view that Lisbon was destroyed because its
+inhabitants were Catholics, whilst the survivors from that disaster
+attributed their misfortune to the fact that they had tolerated a few
+Protestant heretics in their midst. To avoid a recurrence of disaster
+certain of these were baptized by force. In the myths relating to
+underground monsters and personages that are said to be the cause of
+earthquakes we see the direct effects which exhibitions of seismic and
+volcanic activity have produced upon the imagination. The beliefs, or
+more properly, perhaps, the poetical fancies, thus engendered have
+exhibited themselves in various forms. Beneath Japan there is said to be
+a catfish, which in other countries is replaced by a mole, a hog, an
+elephant or other living creature, which when it is restless shakes the
+globe. The Kamchadales picture a subterranean deity called Tuil, who in
+Scandinavian mythology is represented by the evil genius Loki. We have
+only to think of the reference in the Decalogue forbidding the making of
+graven images of that which is in the earth beneath, to see in early
+Biblical history evidence of a subterranean mythology; and it seems
+probable that the same causes which led to the creation of Pluto, Vulcan
+and Poseidon gave rise to practices condemned by Moses.
+
+
+  Building to withstand earthquakes.
+
+Perhaps the greatest practical benefits derived from seismological
+investigations relate to important changes and new principles which have
+been introduced into the arts of the engineer and builder when
+constructing in earthquake countries. The new rules and formulae, rather
+than being theoretical deductions from hypotheses, are the outcome of
+observation and experiment. True measures of earthquake motion have been
+given to us by modern seismometers, with the result that seismic
+destructivity can be accurately expressed in mechanical units. From
+observation we now know the greatest acceleration and maximum velocity
+of an earth particle likely to be encountered; and these are measures of
+the destructivity. The engineer is therefore dealing with known forces,
+and he has to bear in mind that these are chiefly applied in a
+horizontal direction. A formula connecting the acceleration requisite to
+overturn bodies of different dimensions has been given. The acceleration
+which will fracture or shatter a column firmly fixed at its foundation
+to the moving earth may be expressed as follows:--
+
+      1  gFAB
+  a = -- ----,
+      6   fw
+
+where
+
+  a = the acceleration per sec. per sec.
+  F = the force of cohesion, or force per unit surface, which when
+        gradually applied produces fracture.
+  A = area of base fractured.
+  B = thickness of the column.
+  f = height of centre of gravity of column above the fractured base.
+  w = the weight of the portion broken off.
+
+With this formula and its derivatives we are enabled to state the height
+to which a wall, for example, may be built capable of resisting any
+assumed acceleration. Experience has shown that yielding first shows
+itself at the base of a pier, a wall or a building, and it is therefore
+clear that the lower portion of such structures should be of greater
+dimensions or stronger than that above. Piers having these increased
+dimensions below, and tapering upwards in a proper manner, so that every
+horizontal section is sufficiently strong to resist the effects of the
+inertia of its superstructure, are employed to carry railways in Japan.
+In that country cast-iron piers are things of the past, whilst piers of
+masonry, together with their foundations, no longer follow the rules of
+ordinary engineering practice.
+
+After flood, fire, earthquake, or when opportunity presents itself,
+changes are introduced in the construction of ordinary buildings. In a
+so-called earthquake-proof house, although externally it is similar to
+other dwellings, we find rafters running from the ridge pole to the
+floor sills, an exceedingly light roof, iron straps and sockets
+replacing mortices and tenons, and many other departures from ordinary
+rules. Masonry arches for bridges or arched openings in walls (unless
+protected by lintels), heavy gables, ornamental copings, cappings for
+chimneys, have by their repeated failure shown that they are undesirable
+features for construction in earthquake countries. As sites for
+buildings it is well to avoid soft ground, on which the movement is
+always greater than on hard ground. Excessive movement also takes place
+along the face of unsupported openings, and for this reason the edges of
+scarps, bluffs, cuttings and river-banks are localities to be avoided.
+In short, the rules and precautions which have to be recognized so as to
+avoid or mitigate the effects of earthquake movement are so numerous
+that students of engineering and architecture in Japan receive a special
+course of lectures on this subject. When it is remembered that a large
+earthquake may entail a loss of life greater than that which takes place
+in many wars, and that for the reconstruction of ordinary buildings,
+factories and public works an expenditure of several million pounds
+sterling is required, the importance of these studies cannot be
+overrated. Severe earthquakes are fortunately unknown in the British
+Isles, but we have simply to turn our eyes to earthquake-shaken colonies
+and lands in close commercial touch with Great Britain to realize the
+importance of mitigating such disasters as much as possible, and any
+endeavour to obviate the wholesale destruction of life should appeal to
+the civilized communities of the world.
+
+
+  Applications of seismometry.
+
+An unexpected application of seismometry has been to record the
+vibration of railway trains, bridges and steamships. An instrument of
+suitable construction will give records of the more or less violent
+jolting and vibratory movements of a train, and so localize
+irregularities due to changes in the character of ballast and sleepers,
+to variation in gauge, &c. An instrument placed on a locomotive throws
+considerable light upon the effects due to the methods of balancing the
+wheels, and by alterations in this respect a saving of fuel of from 1 to
+5 lb. of coal per mile per locomotive has sometimes been effected.
+
+By mapping the centres from which earthquakes originate off the coast of
+Japan, we have not only determined districts where geological activity
+is pronounced, but have placed before the cable engineer well-defined
+localities which it is advisable to avoid; and in the records of unfelt
+earthquakes which originate far from land similar information is being
+collected for the deeper parts of the oceans. Occasionally these records
+have almost immediately made clear the cause of a cable failure. From
+lack of such information in 1888, when the cables connecting Australia
+with the outer world were simultaneously broken, the sudden isolation
+was regarded as a possible operation of war, and the colonists called
+out their naval and military reserves. Records of earthquakes
+originating at great distances have also frequently enabled us to
+anticipate, to correct, to extend, or to disprove telegraphic accounts
+of the disasters. Whatever information a seismogram may give is certain,
+whilst the information gathered from telegrams may in the process of
+transit become exaggerated or minimized. Otherwise unaccountable
+disturbances in records from magnetographs, barographs and other
+instruments employed in observatories are frequently explained by
+reference to the traces yielded by seismometers. Perhaps the greatest
+triumph in seismological investigation has been the determination of the
+varying rates at which motion is propagated through the world. These
+measurements have already thrown new light upon its effective rigidity,
+and if we assume that the density of the earth increases uniformly from
+its surface towards its centre, so that its mean density is 5.5, then,
+according to Knott, the coefficient of elasticity which governs the
+transmission of preliminary tremors of an earthquake increases at a rate
+of nearly 1.2% per mile of descent.     (J. Mi.)
+
+  AUTHORITIES.--J. Milne, _Seismology_ (London, 1898), _Earthquakes_
+  (London, 1898), Bakerian Lecture, "Recent Advances in Seismology,"
+  _Proc. Roy. Soc._, 1906, 77, p. 365; J.A. Ewing, _Memoir on Earthquake
+  Measurement_ (Tokyo, 1883); C.E. Dutton, _Earthquakes in the Light of
+  the New Seismology_ (London, 1904); "The Charleston Earthquake of Aug.
+  31, 1886," Ninth Annual _Report_ of the United States Geological
+  Survey, 1889; W.H. Hobbs, _Earthquakes, an Introduction to Seismic
+  Geology_ (London, 1908), "The San Francisco Earthquake and Fire,
+  1906," _Bull. U.S. Geol. Surv._ No. 324; "The California Earthquake of
+  Ap. 18, 1906," _Rep. State Earthq. Com._ (Washington, D.C., 1908);
+  R.D. Oldham, "Report on the Great Earthquake of 12 June 1897," _Mem.
+  Geol. Surv. India_, xxix. 1899, "On the Propagation of Earthquake
+  Motion to great Distances," _Phil. Trans._, 1900, A, vol. 194, p. 135,
+  "The Constitution of the Interior of the Earth as revealed by
+  Earthquakes," _Quar. Jour. Geol. Soc._, 1906, 62, p. 456; 1907, 63, p.
+  344; C. Davison, _A Study of Recent Earthquakes_ (London, 1905); _The
+  Hereford Earthquake of December 17, 1896_ (Birmingham, 1899), "The
+  Investigation of Earthquakes," _Beiträge z. Geophysik_, Bd. ix., 1908,
+  p. 201, and papers on British earthquakes in _Quart. Jour. Geol.
+  Soc._; T.J.J. See, "The Cause of Earthquakes, Mountain Formation and
+  Kindred Phenomena connected with the Physics of the Earth," _Proc.
+  Amer. Phil. Soc._, 1906, 45, p. 273; F. Frech, "Erdbeben und
+  Gebirgsbau," _Petermann's Mitteilungen_, Bd. 53, 1907, p. 245 (with
+  maps); C.G. Knott, _The Physics of Earthquake Phenomena_ (Oxford,
+  1908); Comte F. de Montessus de Ballore, _Les Tremblements de terre:
+  géographie séismologique_ (Paris, 1906), _La Science séismologique_
+  (1907); _Transactions of the Seismological Society of Japan;
+  Seismological Journal_ (Yokohama); _Bollettino della Società
+  Sismologica Italiana_ (Rome); _Reports of the British Association_,
+  containing the annual reports of the Committee for Seismological
+  Investigations; papers in the _Beiträge zur Geophysik_ and the
+  _Ergänzungsbände_.
+
+
+FOOTNOTES:
+
+  [1] The publications for 1880-1892 were termed the _Transactions of
+    the Seismological Society of Japan_, and for 1893-1895 the
+    _Seismological Journal of Japan_. The observations are now published
+    by the Earthquake Investigation Committee of Japan, and edited by F.
+    Omori, professor of seismology at the university of Tokyo.
+
+  [2] The chief Italian station is at Rocca di Papa near Rome. It is
+    equipped with delicate instruments designed by its director, Giovanni
+    Agamennone. The records since 1895 are published in the _Bollettino
+    della Società Sismologica Italiana_, edited by Luigi Palazzo,
+    director of the Central Office for Meteorology and Geodynamics at
+    Rome.
+
+  [3] The chief Austrian publications are:--_Mittheilungen der
+    Erdbebencommission der k. Akad. der Wissen. in Wien_ (since 1897);
+    _Die Erdbebenwarte_ (1901-1907); and the "Neueste
+    Erdbebennachrichten, _Beilage der Monatsschrift Die Erdbebenwarte_."
+
+  [4] The "International Seismological Association" was founded at
+    Strassburg in 1903, and publishes the _Beiträge zur Geophysik_,
+    edited by George Gerland, director of the Strassburg station; the
+    papers are printed in several languages.
+
+  [5] The records of the British Association stations are published
+    (since 1896) in the _Reports_. Chile has a national earthquake
+    service (founded after the Valparaiso earthquake of August 1906)
+    directed by comte de Montessus de Ballore.
+
+
+
+
+EARTH-STAR (_Geaster_), in botany, a kind of puff-ball, with a distinct
+outer coat which, on separating from the inner, splits into several
+divisions, which become reflexed and spread like a star. The inner coat
+enveloping the spores is supported, like a ball, either with or without
+a stalk on the upper face of the star. The spores escape generally by
+means of a distinct aperture which appears in the top of the ball. There
+are several species in Britain found on the ground or on decaying
+leaves. They are rare or local, but more common in the south or
+south-east of England than in other parts of Britain.
+
+[Illustration: From Strasburger's _Lehrbuch der Botanik_, by permission
+of Gustav Fischer.
+
+_Geaster Granulosus_, nat. size.]
+
+
+
+
+EARTHWORM, the common name of a chaetopod worm found nearly all over the
+world. Linnaeus recognized only one species of earthworm and named it
+_Lumbricus terrestris_. There are now one thousand well-characterized
+species known from different parts of the world, and the number
+increases almost daily. The earthworms of England belong entirely to the
+three genera _Lumbricus_, _Allolobophora_ and _Allurus_, which are
+further subdivided by some systematists; and these genera form the
+prevalent earthworm fauna of the Palaearctic region and are also very
+numerous in the Nearctic region. Elsewhere they do not appear to be
+indigenous, but are replaced by the numerous other genera of the
+families enumerated in the article CHAETOPODA (q.v.). It is a remarkable
+fact that these genera, comprizing a separate family _Lumbricidae_, when
+introduced into tropical and other countries, thrive abundantly and oust
+the indigenous forms. In gatherings of earthworms from various
+extra-European countries it is always found that if the collections have
+been made in cultivated ground and near the coast the worms are of
+European species; farther inland the native forms are met with. Inasmuch
+as in every case the _Lumbricidae_ from non-European countries are
+identical with European species, since it has been shown that these
+animals are very readily introduced accidentally with plants, &c., and
+in view of the fact that they are impatient of sea water, it seems clear
+that the presence of these _Lumbricidae_ in other continents is due to
+accidental transportation. Most earthworms live in the soil, which they
+devour as they burrow through it. A few, like their allies the river
+worms (Limicolae), habitually frequent streams, lakes, &c. One genus, at
+any rate, viz. _Pontodrilus_, seeks an unusual environment, and is found
+in heaps of sea-weed cast up by the sea. The range of this genus is
+therefore naturally wider than that of other genera which are confined
+to land masses and cannot cross the sea by their own efforts. It might
+be inferred, therefore, and the inference is proved by facts, that truly
+oceanic islands have no indigenous fauna of earthworms, but are
+inhabited by forms which are identical with those of neighbouring
+continents, and doubtless, therefore, accidentally introduced.
+
+Like the leeches the earthworms produce cocoons which are a product of
+the glandular epithelium of the clitellum. In these cocoons are
+deposited the eggs together with a certain amount of albumen upon which
+the developing embryos feed. So far as is known, the production of
+cocoons is universal among earthworms and the remaining Oligochaeta of
+aquatic habit. The young leave the cocoon as fully formed earthworms in
+which, however, the genitalia are not fully developed. There is no free
+living larval stage. Out of a single cocoon emerge a varying number of
+young worms, the numbers being apparently characteristic of the species.
+The work of earthworms in aiding in the production of the subsoil and in
+levelling the surface was first studied by C. Darwin, and has since been
+investigated by others. This work is partly carried out beneath the
+surface and partly on the surface, upon which the worms wander at night
+and eject the swallowed and triturated earth; frequently castings of
+some height are formed of coiled ropes of agglutinated particles of
+mould. The indigenous species of Great Britain, about twenty in number,
+do not grow to a greater length than some 10 in.; but in several
+tropical countries there are species which grow to a length of from 3 to
+6 ft. Thus we have in Natal the gigantic _Microchaeta rappi_, in Ceylon
+_Megascolex coeruleus_, in Australia _Megascolides australis_, and an
+equally large form in South America.     (F. E. B.)
+
+
+
+
+EARWIG, an insect belonging to the _Forficulidae_, a family usually
+referred to the Orthoptera, but sometimes regarded as typifying a
+special order, to which the names Dermaptera, Dermatoptera and
+Euplexoptera have been given, in allusion to certain peculiarities in
+the structure of the wings in the species that possess them. The front
+wings are short and horny and when at rest meet without overlapping in
+the middle line, like the wing-cases of brachelytrous (cocktail)
+beetles. The hind wings, on the contrary, are for the most part
+membranous and, when extended, of large size; each consists of two
+portions, the distal of which, in virtue of the arrangement and jointing
+of its nervures, is capable of being both doubled up and folded fanwise
+beneath the proximal, which is partly horny when the wing is tucked away
+under the front wing-case of the same side. Apart from these
+characteristics, the most distinctive feature of earwigs is the presence
+at the end of the abdomen of a pair of pincers which are in reality
+modified appendages, known as cercopods, and represent the similar limbs
+of _Japyx_ and the caudal feelers of _Campodea_ and some other insects.
+
+The _Forficulidae_ are almost cosmopolitan; but the various species and
+genera differ from each other both in structure and size to a
+comparatively slight extent. The length and armature of the pincers and
+the presence or absence of wings are perhaps the most important features
+used by systematists in distinguishing the various kinds. Of particular
+zoological interest in this connexion is a Ceylonese genus _Dyscritina_,
+in which the cercopods are long, many-jointed and filiform during the
+early stages of growth, and only assume at the last moult the forcipate
+structure characteristic of the family. The best known earwig is the
+common European species, _Forficula auricularia_. This insect is
+gregarious and nocturnal. It hides by day under stones or the loosened
+bark of trees or in any crevice or hole sheltered from the light. At
+night it crawls about in search of food, which consists to a small
+extent of dead animal or vegetable matter, but principally, as gardeners
+are aware, of the petals and other parts of flowers of growing shoots
+and soft ripe fruit. During the winter earwigs lie dormant; but in the
+early months of the year females with their eggs may be found in the
+soil, frequently in deserted earthworm burrows. Maternal instincts are
+well developed, both the eggs, which number about fifty, and the young
+being carefully brooded and watched over by the parent. Except for the
+absence of wings, the young are miniature models of the adult. As growth
+proceeds the integument is periodically cast; and at the final moult the
+perfect winged insect appears. Males and females are like each other in
+size, but may be distinguished by the difference in the number of
+visible abdominal segments, the male having nine and the female seven.
+In the male, moreover, the pincers are caliper-like and toothed at the
+base, whereas in the female they are untoothed and only lightly curved
+at the tip. These differences suggest that the pincers aid in the
+pairing of the sexes. However that may be, they are known to be used in
+the folding of the wings; and their importance as weapons of defence is
+attested by the precision and effect with which they are wielded against
+assailants like ants.     (R. I. P.)
+
+
+
+
+EASEMENT (Fr. _aise_; O. Fr. _aisement_; Anglo-Lat. _aisiamentum_, a
+privilege or convenience), in English law, a species of "servitude" or
+limited right of use over land belonging to another. It is distinguished
+from _profits à prendre_--another species of servitude which involves a
+right to participate in the profits of the soil of another--since an
+easement confers merely a convenience (_aisiamentum_) to be exercised
+over the land of another (without any participation in the profits of
+it), i.e. a right to use the soil or produce of the soil in a way
+tending to the more convenient enjoyment of another piece of land. Thus
+a right of way is an easement, a right of common is a profit. An
+easement is distinguishable also from a licence, which, unless it is
+coupled with a grant, is personal to both grantor and grantee and is
+neither binding on the licensor, nor, in general, assignable by the
+licensee; while both the benefit and the burden of an easement are
+annexed to land (Gale on _Easements_, 8th ed. p. 2). With easements are
+sometimes classed certain closely allied "natural rights," such as a
+landowner's right to lateral support for his soil in its natural state,
+and a riparian owner's right to the natural flow of a stream.
+
+The essential features of an easement, in the strict sense of the term,
+are therefore these: (i.) It is an incorporeal right; a right to the use
+and enjoyment of land--not to the land itself; (ii.) it is imposed upon
+corporeal property; (iii.) it is a right without profit; (iv.) it
+requires for its constitution two distinct tenements--the "dominant
+tenement" which enjoys the right, and the "servient tenement" which
+submits to it. This last characteristic excludes from the category of
+easements the so-called "easements _in gross_," such as a right of way
+conferred by grant independently of the possession of any tenement by
+the grantee. The true easement is an "appendant" or "appurtenant" right,
+not a "right in gross."
+
+Further classifications of easements must be noted. They are divided
+into (a) _affirmative_ or _positive_, those which authorize the
+commission of an act by the dominant owner, e.g. rights of way, a right
+to draw water from a spring, rights of aqueduct, and _negative_, when
+the easement restricts the rights of the servient owner over his own
+property, e.g. prevents him from building on land so as to obstruct
+ancient lights (cf. also the right to the support of neighbouring soil);
+(b) _continuous_, of which the enjoyment may be continual without the
+interference of man, e.g. access to light, and _discontinuous_, where
+there must be a fresh act on each occasion of the exercise of the right,
+e.g. a right of way, or right to draw water; (c) _apparent_, where there
+are visible external signs of the exercise of the right, e.g. a right to
+dam up a watercourse, and _non-apparent_, where such signs are absent,
+e.g. a right to lateral support from land, a prohibition to build above
+a certain height.
+
+_Acquisition of Easements._--Easements may be acquired (a) by express
+grant, either by statute, or by deed _inter vivos_, or by will; (b) by
+an implied grant; (c) by express or implied reservation, e.g. by the
+owner of land in selling the fee (as to implied reservation, see Gale on
+_Easements_, 8th ed. pp. 137 et seq.); (d) by prescription, either at
+common law or under the Prescription Act 1832. An express grant, or
+express reservation, of an easement cannot be effected except by deed.
+An easement arises by implied grant where a man makes one part of his
+tenement dependent on another, or makes the parts mutually
+interdependent, and grants any such part with the dependence attaching
+to it to another person (Innes, _Law of Easements_, 7th ed. p. 10). For
+example, a man builds two houses, each of which by the plan of
+construction receives support from the other; this mutual right of
+support is a _quasi_-easement, of which on severance of the tenements
+the grantee of one will have the benefit; where the enjoyment of the
+severed tenement could not be had at all without such a right, it is
+said to be an "easement of necessity."
+
+Easements are acquired by prescription at common law by proof of
+"immemorial user" by the dominant owner and those through whom he
+claims. At one time it was thought that such proof must date back to the
+first year (1189) of Richard I. (see preamble to Prescription Act 1832).
+The ground, however, on which prescription was admitted as a means of
+acquiring easements was the fiction of a "lost grant." Long enjoyment of
+the right pointed to its having had a legal origin in a grant from the
+servient owner, and so any period of reasonably long use came to be
+accepted. A "lost grant" may be presumed to have been made (the question
+is one of fact) if 20 years' uninterrupted enjoyment is shown. To avoid
+the difficulties of proof of prescriptive right at common law, the
+Prescription Act 1832 established shorter periods of user. In the case
+of easements, other than light, the periods of prescription are 20 years
+for a claim that may be defeated, and 40 years for an indefeasible claim
+(s. 2). The right of access of light is dealt with under s. 3 (see
+ANCIENT LIGHTS). The enjoyment to become prescriptive must be open, i.e.
+of such a character that the owner of the tenement said to be servient
+has a reasonable opportunity of becoming aware of the adverse claim
+(_Union Lighterage Co._ v. _London Graving Dock Co._, 1902, 2 Ch. 557);
+and it must be enjoyed as of right (_Gardner_ v. _Hodgson's Kingston
+Brewery Co._, 1903, A.C. 229) as against the owner of the tenement
+affected (_Kilgour_ v. _Gaddes_, 1904, 1 K.B. 457). The periods of
+prescription are to be reckoned backwards from the time when some suit
+or matter involving the claim of the dominant owner has arisen (s. 4).
+Nothing is to be deemed an interruption unless the act of interruption
+has been submitted to, or acquiesced in, for a year (s. 4).
+
+Easements may be extinguished (i.) by express release--here an
+instrument under seal is necessary; (ii.) by "merger," i.e. where both
+tenements become the property of the same owner; (iii.) by abandonment
+through non-user. In the case of discontinuous easements, the shortest
+period of non-user may suffice if there is direct evidence of an
+intention to abandon.
+
+A word may be added here as to the right to air. It is an actionable
+nuisance to cause pollution of the air entering a dwelling-house. The
+owner of a dwelling-house may by prescription acquire a right to the
+passage of air through it by a defined channel; and the enjoyment
+without interruption of ventilation by means of air flowing in a
+definite channel, with the knowledge of the owner and occupier of the
+adjoining premises, creates a presumption of the grant of such an
+easement (see Gale on _Easements_, 8th ed. p. 338).
+
+In _Scots Law_ the term "easement" is unknown. Both the name "servitude"
+and the main species of servitudes existing in Roman law (q.v.) have
+been adopted. The classification of servitudes into positive and
+negative, &c., and the modes of their creation and extinction, are
+similar to those of English law. The statutory period of prescription is
+40 years (Scots Acts 1617, c. 12), or 20 years in the case of enjoyment
+under any _ex facie_ valid irredeemable title duly recorded in the
+appropriate register of sasines (Conveyancing [Scotland] Act 1874).
+There are certain servitudes special to Scots law, e.g. "thirlage," by
+which lands are "thirled" or bound to a particular mill, and the
+possessors obliged to grind their grain there, for payment of certain
+_multures_ (quantities of grain or meal, payable to the mill-owner) and
+_sequels_ (small quantities given to the mill servants) as the customary
+price of grinding. Statutory provision has been made for the commutation
+of these duties (Thirlage Act 1799), and they have now almost
+disappeared.
+
+The French Code Civil (Arts. 637 et seq.) and the other European codes
+(e.g. Belgium, arts. 637 et seq.; Holland, arts. 721 et seq.; Italy,
+arts. 531 et seq.; Spain, arts. 530 et seq.; Germany, arts. 1018 et
+seq.) closely follow Roman law. French law is in force in Mauritius, and
+has been followed in Quebec (Civil Code, arts. 499 et seq.) and St Lucia
+(Civil Code, arts. 449 et seq.). In India the law is regulated, on
+English lines, by the Easements Act 1882 (Act v. of 1882). The term
+"easements," however, in India includes _profits à prendre_. In the
+South African colonies the law of easements is based on the Roman Dutch
+law (see Maasdorp, _Institutes of Cape Law_, 1904; Bk. ii. p. 166 et
+seq.). In most of the other colonies the law of easements is similar to
+English law. In some, however, it has been provided by statute that
+rights to the access and use of light or water cannot be acquired by
+prescription: e.g. Victoria (Water Act 1890, No. 1156, s. 3), Ontario
+(Real Property Limitation Act, Revised Stats. Ontario, 1897; c. 133, s.
+36, light).
+
+In the _United States_ the law of easements is founded upon, and
+substantially identical with, English law. The English doctrine,
+however, as to acquisition of right of light and air by prescription is
+not accepted in most of the States.
+
+  AUTHORITIES.--_English Law_: Gale, _Law of Easements_ (8th ed.,
+  London, 1908); Goddard, _Law of Easements_ (6th ed., London, 1904);
+  Innes, _Digest of the Law of Easements_ (7th ed., London, 1903).
+  _Indian Law_: Peacock, _Easements in British India_ (Calcutta, 1904);
+  Hudson and Inman, _Law of Light and Air_ (2nd ed., London, 1905).
+  _Scots Law_: Erskine, _Principles of the Law of Scotland_ (20th ed.,
+  Edinburgh, 1903). _American Law_: Jones, _Law of Easements_ (New York,
+  1898); Bouvier, _Law Dict._ (Boston and London, 1897); _Ruling Cases_,
+  London and Boston, 1894-1901, tit. _Easement_ (American Notes).
+       (A. W. R.)
+
+
+
+
+EAST, ALFRED (1849-   ), English painter and etcher, was born at
+Kettering on the 15th of December 1849. One of the most prominent among
+modern English landscape painters, he received his art education first
+at the Glasgow School of Art and then in Paris at the École des
+Beaux-Arts, and under Robert-Fleury and Bouguereau. His landscapes are
+remarkable for the lyrical use of colour and for the pleasing rhythm of
+line which is the result of careful selection and building up of the
+elements that constitute the scene. Based on keen observation of the
+colour of nature and on careful studies of the details, they are
+arranged with a rare and by no means obvious sense of balance and
+compositional beauty which summarily discards all disturbing accidents
+of nature. He also achieved distinction as an etcher, and published an
+instructive and useful volume on landscape painting (London, 1906). He
+began to exhibit at the Royal Academy in 1882, and was elected an
+associate. In 1906 he became president of the Royal Society of British
+Artists. Many of his works are to be found in the English provincial
+galleries; Manchester owns "The Silent Somme" and "Autumn"; Liverpool,
+"Gibraltar from Algeciras"; Leeds, "The Golden Valley"; Birmingham,
+"Hayle from Lelant"; Preston, "An Idyll of Spring"; and Hull, "Evening
+on the Cotswolds." His "Passing Storm" is at the Luxembourg; "The Nene
+Valley" at the Venice gallery; and "A Haunt of Ancient Peace" at the
+National gallery in Budapest. In 1903 he received the order of the Crown
+of Italy in connexion with his services to the Venice international
+exhibition; and he was made an honorary member of the Japanese Meiji
+Bijutsu Kai.
+
+
+
+
+EAST ANGLIA, one of the kingdoms into which Anglo-Saxon Britain was
+divided. Bede gives no information about its origin except that its
+earliest settlers were Angles. The kingdom of East Anglia comprised the
+two counties of Norfolk and Suffolk. With regard to the western boundary
+we have no accurate information, but it was probably formed by the fens
+of Cambridgeshire.
+
+This kingdom first appears in Bede's narrative early in the 7th century,
+when its power was at its height. Towards the end of the reign of
+Æthelberht, who died about 616, Rædwald of East Anglia, who had
+apparently spent some time at the court of Kent, began to win for
+himself the chief position among the Anglo-Saxon kings of his day. His
+position was assured, at least temporarily, in 617, when he decided to
+espouse the cause of the Northumbrian prince Edwin, then a fugitive at
+his court, and defeated Æthelfrith of Northumbria on the banks of the
+Idle, a tributary of the Trent, in Mercian territory. Rædwald had been
+converted to Christianity in Kent, but after his return home he
+relapsed, according to Bede, owing to the influence of his wife, and
+there were to be seen in the same building a Christian and a pagan
+altar. Bede states that Rædwald was the son of Tytili, the son of Wuffa,
+from whom the East Anglian royal family derived their name Wuffingas.
+According to the _Historia Brittonum_ Guffa (Wuffa) was the son of
+(Guecha) Wehha, who first ruled the East Angles in Britain. This would
+put the organization of the kingdom in the first or second quarter of
+the 6th century. Eorpwald, the son of Rædwald, was converted to
+Christianity by Edwin, but was soon afterwards slain by Ricberht (627 or
+628), whereupon the kingdom again became pagan for three years, when
+Sigeberht, the brother of Eorpwald, became king and founded a see for
+Felix at Dunwich. Sigeberht also founded a school in East Anglia, and on
+the arrival of an Irish missionary named Furseus he built him a
+monastery at _Cnobheresburg_, perhaps to be identified with Burgh
+Castle. Before 644, however, Sigeberht resigned the crown in favour of
+his brother Ecgric and retired to a monastery. Shortly afterwards both
+brothers were slain by Penda of Mercia in his invasion of East Anglia,
+and Anna became king. This king was an enthusiastic Christian, and
+converted Coenwalh, king of Wessex, who had fled to his court. Two of
+his daughters, Sæthryth and Æthelberg, took the veil; while another,
+Sexburg, was married to Earconberht, king of Kent; and a fourth,
+Æthelthryth, after two marriages, with Tondberht of the South Gyrwe and
+Ecgfrith of Northumbria, became abbess of Ely. In 654 Anna was slain by
+Penda of Mercia, and was succeeded by his brother Æthelhere, who was
+killed in 655 at the Winwaed, fighting for the Mercian king against
+Oswio of Northumbria. In 673 Archbishop Theodore divided the East
+Anglian diocese into two, Elmham being the seat of the northern, Dunwich
+that of the southern bishop. A long blank follows in the history of this
+kingdom, until in 792 we find Offa of Mercia slaying Æthelberht, king of
+East Anglia, who is said to have been his son-in-law. East Anglia was
+subject to the supremacy of the Mercian kings until 825, when its people
+slew Beornwulf of Mercia, and with their king acknowledged Ecgberht
+(Egbert) of Wessex as their lord. In 870 Edmund, king of East Anglia,
+was killed by the Danes under I'varr and Ubbi, the sons of Ragnar
+Loðbrok.
+
+The following is a list of the kings of East Anglia of whom there is
+record:--Wehha; Wuffa; Rædwald, son of Tytili and grandson of Wuffa
+(reigning 617); Eorpwald, son of Rædwald (d. 627 or 628); Sigeberht,
+brother of Eorpwald; Ecgric, brother of Sigeberht (both slain before
+644); Anna, son of Ene and grandson of Tytili (d. 654); Æthelhere,
+brother of Anna (d. 655); Æthelwald, a third brother; Aldwulf (succ.
+663, d. 713), son of Æthelric and grandson of Ene; Elfwald, son of
+Aldwulf (d. 749); Hun Beonna and Alberht; Æthelberht (792); Edmund
+(870).
+
+After the death of Ragnar Loðbrok's sons East Anglia was occupied by the
+Danish king Guthrum, who made a treaty with Alfred settling their
+respective boundaries, probably about 880. Guthrum died in 890. A later
+king named Eohric took up the cause of Æthelwald, the son of Æthelred
+I., and was slain in the fight with the Kentish army at the Holm in 905.
+A war broke out with King Edward the Elder in 913; in 921 a king whose
+name is unknown was killed at the fall of Tempsford, and in the same
+year the Danes of East Anglia submitted to Edward the Elder. From this
+time, probably, East Anglia was governed by English earls, the most
+famous of whom were Æthelstan, surnamed Half-King (932-956) and his
+sons, Æthelwold (956-962), and Æthelwine, surnamed _Dei amicus_
+(962-992).
+
+  See Bede, _Hist. Eccl._ (ed. C. Plummer, Oxford. 1896), ii. 5, 15,
+  iii. 7, 8, 18-20, 22, iv. 3, 5, 23; _Saxon Chronicle_ (ed. Earle and
+  Plummer, Oxford, 1899), s. a. 823, 838, 866, 870, 880, 885, 890, 894,
+  905, 921; _Historia Brittonum_ (San-Marte, 1844), s. 59; H. Sweet,
+  _Oldest English Texts_, p. 171 (London, 1885).     (F. G. M. B.)
+
+
+
+
+EASTBOURNE, a municipal borough (1883) in the Eastbourne parliamentary
+division of Sussex, England, 61 m. S.S.E. of London by the London,
+Brighton & South Coast railway. Pop. (1891) 34,969; (1901) 43,344;
+(local census, 1909) 49,286. It is situated 3 m. N.E. of Beachy Head,
+the loftiest headland on the English Channel coast. It once consisted of
+three parts--the village of East Bourne, a mile inland; South Bourne,
+lying back from the shore; and Seahouses, facing the beach. The church
+of St Mary, the ancient parish church of East Bourne, is a fine
+transitional Norman building; and there are numerous modern churches and
+chapels. The principal buildings and institutions are the town hall and
+municipal buildings, the Princess Alice Memorial and other hospitals, a
+free library and, among many high-class schools, Eastbourne College for
+boys, founded in 1867. There is a fine pier with pavilion, and a marine
+parade nearly 3 m. in extent, arranged in terraced promenades.
+Devonshire Park of 13 acres is pleasantly laid out, and contains a
+pavilion and a theatre. The duke of Devonshire is the principal
+landowner. Golf links are laid out on the neighbouring downs. A Roman
+villa was formerly seen close to the shore, but it is not now visible.
+The corporation consists of a mayor, 8 aldermen and 24 councillors. In
+1910 the corporation promoted a bill in parliament to add the Hampden
+Park district in the parish of Willingdon to the borough and to make
+Eastbourne, with this extension, a county borough.
+
+
+
+
+EAST CHICAGO, a city of Lake county, Indiana, U.S.A., on Lake Michigan,
+about 19 m. S.E. of the business centre of Chicago. Pop. (1890) 1255;
+(1900) 3411 (1331 foreign-born); (1910) 19,098. It is served by several
+railways, including the Pennsylvania, the Wabash, the Chicago Terminal
+Transfer (whose shops are here), the Lake Shore & Michigan Southern, the
+Chicago, Indiana & Southern, and the Indiana Harbor railways. East
+Chicago covers an area whose greatest dimensions are 4 by 3½ m. That
+part of the city along the lake, known as Indiana Harbor, dates from
+1901 and has grown very rapidly because of its position at the
+southernmost part of the Calumet District, and because of the meeting
+here of railway and lake commerce. A good harbour has been constructed,
+a new ship canal connecting the harbour with the Calumet river. East
+Chicago is industrially virtually a part of "Greater" Chicago; among its
+manufactures are iron and steel, cement, lumber, boilers, hay presses,
+chains, chemicals and foundry products. East Chicago was chartered as a
+city in 1893.
+
+
+
+
+EASTER, the annual festival observed throughout Christendom in
+commemoration of the resurrection of Jesus Christ. The name Easter (Ger.
+_Ostern_), like the names of the days of the week, is a survival from
+the old Teutonic mythology. According to Bede (_De Temp. Rat._ c. xv.)
+it is derived from _Eostre_, or _Ostâra_, the Anglo-Saxon goddess of
+spring, to whom the month answering to our April, and called
+_Eostur-monath_, was dedicated. This month, Bede says, was the same as
+the _mensis paschalis_, "when the old festival was observed with the
+gladness of a new solemnity."
+
+The name of the festival in other languages (as Fr. _pâques_; Ital.
+_pasqua_; Span. _pascua_; Dan. _paaske_; Dutch _paasch_; Welsh _pasg_)
+is derived from the Lat. _pascha_ and the Gr. [Greek: pascha]. These in
+turn come from the Chaldee or Aramaean form [Hebrew: pascha] _pascha'_,
+of the Hebrew name of the Passover festival [Hebrew: pesach] _pesach_,
+from [Hebrew: pasach] "he passed over," in memory of the great
+deliverance, when the destroying angel "passed over the houses, of the
+children of Israel in Egypt when he smote the Egyptians" (Exod. xii.
+27).
+
+An erroneous derivation of the word _pascha_ from the Greek [Greek:
+paschein], "to suffer," thus connected with the sufferings or passion of
+the Lord, is given by some of the Fathers of the Church, as Irenaeus,
+Tertullian and others, who were ignorant of Hebrew. St Augustine (_In
+Joann. Tract._ 55) notices this false etymology, shows how similarity of
+sound had led to it, and gives the correct derivation.
+
+There is no indication of the observance of the Easter festival in the
+New Testament, or in the writings of the apostolic Fathers. The sanctity
+of special times was an idea absent from the minds of the first
+Christians. "The whole of time is a festival unto Christians because of
+the excellency of the good things which have been given" is the comment
+of St Chrysostom on 1 Cor. v. 7, which has been erroneously supposed to
+refer to an apostolic observance of Easter. The ecclesiastical historian
+Socrates (_Hist. Eccl._ v. 22) states, with perfect truth, that neither
+the Lord nor his apostles enjoined the keeping of this or any other
+festival. He says: "The apostles had no thought of appointing festival
+days, but of promoting a life of blamelessness and piety"; and he
+attributes the observance of Easter by the church to the perpetuation of
+an old usage, "just as many other customs have been established."
+
+This is doubtless the true statement of the case. The first Christians
+continued to observe the Jewish festivals, though in a new spirit, as
+commemorations of events which those festivals had foreshadowed. Thus
+the Passover, with a new conception added to it of Christ as the true
+Paschal Lamb and the first fruits from the dead, continued to be
+observed, and became the Christian Easter.
+
+Although the observance of Easter was at a very early period the
+practice of the Christian church, a serious difference as to the day for
+its observance soon arose between the Christians of Jewish and those of
+Gentile descent, which led to a long and bitter controversy. The point
+at issue was when the Paschal fast was to be reckoned as ending. With
+the Jewish Christians, whose leading thought was the death of Christ as
+the Paschal Lamb, the fast ended at the same time as that of the Jews,
+on the fourteenth day of the moon at evening, and the Easter festival
+immediately followed, without regard to the day of the week. The Gentile
+Christians, on the other hand, unfettered by Jewish traditions,
+identified the first day of the week with the Resurrection, and kept the
+preceding Friday as the commemoration of the crucifixion, irrespective
+of the day of the month. With the one the observance of the day of the
+month, with the other the observance of the day of the week, was the
+guiding principle.
+
+Generally speaking, the Western churches kept Easter on the first day of
+the week, while the Eastern churches followed the Jewish rule, and kept
+Easter on the fourteenth day. St Polycarp, the disciple of St John the
+Evangelist and bishop of Smyrna, visited Rome in 159 to confer with
+Anicetus, the bishop of that see, on the subject; and urged the
+tradition, which he had received from the apostle, of observing the
+fourteenth day. Anicetus, however, declined to admit the Jewish custom
+in the churches under his jurisdiction, but readily communicated with
+Polycarp and those who followed it. About forty years later (197) the
+question was discussed in a very different spirit between Victor, bishop
+of Rome, and Polycrates, metropolitan of proconsular Asia. That province
+was the only portion of Christendom which still adhered to the Jewish
+usage, and Victor demanded that all should adopt the usage prevailing at
+Rome. This Polycrates firmly refused to agree to, and urged many weighty
+reasons to the contrary, whereupon Victor proceeded to excommunicate
+Polycrates and the Christians who continued the Eastern usage. He was,
+however, restrained from actually proceeding to enforce the decree of
+excommunication, owing to the remonstrance of Irenaeus and the bishops
+of Gaul. Peace was thus maintained, and the Asiatic churches retained
+their usage unmolested (Euseb. _H.E._ v. 23-25). We find the Jewish
+usage from time to time reasserting itself after this, but it never
+prevailed to any large extent.
+
+A final settlement of the dispute was one among the other reasons which
+led Constantine to summon the council of Nicaea in 325. At that time the
+Syrians and Antiochenes were the solitary champions of the observance of
+the fourteenth day. The decision of the council was unanimous that
+Easter was to be kept on Sunday, and on the same Sunday throughout the
+world, and "that none should hereafter follow the blindness of the
+Jews" (Socrates, _H.E._ i. 9). The correct date of the Easter festival
+was to be calculated at Alexandria, the home of astronomical science,
+and the bishop of that see was to announce it yearly to the churches
+under his jurisdiction, and also to the occupant of the Roman see, by
+whom it was to be communicated to the Western churches. The few who
+afterwards separated themselves from the unity of the church, and
+continued to keep the fourteenth day, were named _Quartodecimani_, and
+the dispute itself is known as the _Quarto-deciman_ controversy.
+Although measures had thus been taken to secure uniformity of
+observance, and to put an end to a controversy which had endangered
+Christian unity, a new difficulty had to be encountered owing to the
+absence of any authoritative rule by which the paschal moon was to be
+ascertained. The subject is a very difficult and complex one (see also
+CALENDAR). Briefly, it may be explained here that Easter day is the
+first Sunday after the full moon following the vernal equinox. This, of
+course, varies in different longitudes, while a further difficulty
+occurred in the attempt to fix the correct time of Easter by means of
+cycles of years, when the changes of the sun and moon more or less
+exactly repeat themselves. At first an eight years' cycle was adopted,
+but it was found to be faulty, then the Jewish cycle of 84 years was
+used, and remained in force at Rome till the year 457, when a more
+accurate calculation of a cycle of 532 years, invented by Victorius of
+Acquitaine, took its place. Ultimately a cycle of 19 years was accepted,
+and it is the use of this cycle which makes the Golden Number and Sunday
+Letter, explained in the preface to the Book of Common Prayer,
+necessary. Owing to this lack of decision as to the accurate finding of
+Easter, St Augustine tells us (_Epist._ 23) that in the year 387 the
+churches of Gaul kept Easter on the 21st of March, those of Italy on the
+18th of April, and those of Egypt on the 25th of April; and it appears
+from a letter of Leo the Great (_Epist._ 64, _ad Marcian._) that in 455
+there was a difference of eight days between the Roman and the
+Alexandrine Easter. Gregory of Tours relates that in 577 "there was a
+doubt about Easter. In Gaul we with many other cities kept Easter on the
+fourteenth calends of May, others, as the Spaniards, on the twelfth
+calends of April."
+
+The ancient British and Celtic churches followed the cycle of 84 years
+which they had originally received from Rome, and their stubborn refusal
+to abandon it caused much bitter controversy in the 8th century between
+their representatives and St Augustine of Canterbury and the Latin
+missionaries. These latter unfairly attempted to fix the stigma of the
+Quartodeciman observance on the British and Celtic churches, and they
+are even now sometimes ignorantly spoken of as having followed the
+Asiatic practice as to Easter. This, however, is quite erroneous. The
+British and Celtic churches always kept Easter according to the Nicene
+decree on a Sunday. The difference between them and the Roman Church, at
+this period, was that they still followed the 84 years' cycle in
+computing Easter, which had been abandoned at Rome for the more accurate
+cycle of 532 years. This difference of calculation led to Easter being
+observed on different Sundays, in certain years, in England, by the
+adherents of the two churches. Thus Bede records that in a certain year
+(which must have been 645, 647, 648 or 651) Queen Eanfleda, who had
+received her instruction from a Kentish priest of the Roman obedience,
+was fasting and keeping Palm Sunday, while her husband, Oswy, king of
+Northumbria, following the rule of the British church, was celebrating
+the Easter festival. This diversity of usage was ended, so far as the
+kingdom of Northumbria was concerned, by the council of Streaneshalch,
+or Whitby, in 654. To Archbishop Theodore is usually ascribed the credit
+of ending the difference in the rest of England in 669.
+
+The Gregorian correction of the calendar in 1582 has once more led to
+different days being observed. So far as Western Christendom is
+concerned the corrected calendar is now universally accepted, and Easter
+is kept on the same day, but it was not until 1752 that the Gregorian
+reformation of the calendar was adopted in Great Britain and Ireland.
+Jealousy of everything emanating from Rome still keeps the Eastern
+churches from correcting the calendar according to the Gregorian
+reformation, and thus their Easter usually falls before, or after, that
+of the Western churches, and only very rarely, as was the case in 1865,
+do the two coincide.
+
+Easter, as commemorating the central fact of the Christian religion, has
+always been regarded as the chief festival of the Christian year, and
+according to a regulation of Constantine it was to be the first day of
+the year. This reckoning of the year as beginning at Easter lingered in
+France till 1565, when, by an ordinance of Charles IX., the 1st of
+January finally took its place.
+
+Four different periods may be mentioned as connected with the observance
+of Easter, viz. (1) the preparatory fast of the forty days of Lent; (2)
+the fifteen days, beginning with the Sunday before and ending with the
+Sunday after Easter, during which the ceremonies of Holy Week and the
+services of the Octave of Easter were observed; this period, called by
+the French the _Quinzaine de Pâques_, was specially observed in that
+country; (3) the Octave of Easter, during which the newly-baptized wore
+their white garments, which they laid aside on the Sunday after Easter,
+known as _Dominica in albis depositis_ from this custom; another name
+for this Sunday was _Pascha clausum_, or the close of Easter, and from a
+clipping of the word "close" the English name of "Low" Sunday is
+believed to be derived; (4) Eastertide proper, or the paschal season
+beginning at Easter and lasting till Whit Sunday, during the whole of
+which time the festival character of the Easter season was maintained in
+the services of the church.
+
+Many ecclesiastical ceremonies, growing up from early times, clustered
+round the celebration of the Easter festival. One of the most notable of
+these was the use of the paschal candle. This was a candle of very large
+dimensions, set in a candlestick big enough to hold it, which was
+usually placed on the north side, just below the first ascent to the
+high altar. It was kept alight during each service till Whitsuntide. The
+Paschal, as it was called at Durham cathedral, was one of the chief
+sights of that church before the Reformation. It was an elaborate
+construction of polished brass, and, contrary to the usual custom, seems
+to have been placed in the centre of the altar-step, long branches
+stretching out towards the four cardinal points, bearing smaller
+candles. The central stem of the candlestick was about 38 ft. high, and
+bore the paschal candle proper, and together they reached a combined
+height of about 70 ft., the candle being lighted from an opening above.
+Other paschal candles seem to have been of scarcely less size. At
+Lincoln, c. 1300, the candle was to weigh three stones of wax; at
+Salisbury in 1517 it was to be 36 ft. long; and at Westminster in 1558
+it weighed no less than 3 cwt. of wax. After Whitsuntide what remained
+was made into smaller candles for the funerals of the poor. In the
+ancient churches at Rome the paschal candlesticks were fixtures, but
+elsewhere they were usually movable, and were brought into the church
+and set up on the Thursday before Easter. At Winchester the paschal
+candlestick was of silver, and was the gift of Canute. Others of more or
+less importance are recorded as having been at Canterbury, Bury St
+Edmunds, Hereford and York. The burning of the paschal candle still
+forms part of the Easter ceremonial of the Roman Catholic Church (see
+LIGHTS, CEREMONIAL).
+
+The liturgical colour for Easter was everywhere white, as the sign of
+joy, light and purity, and the churches and altars were adorned with the
+best ornaments that each possessed. Flowers and shrubs no doubt in early
+times were also used for this purpose, but what evidence there is goes
+against the medieval use of such decorations, which are so popular at
+the present day.
+
+It is not the purpose of this article to enter on the wide subject of
+the popular observances, such as the giving and sending of Pasch or
+Easter eggs as presents. For such the reader may consult Brand's
+_Popular Antiquities_, Hone's _Every-Day Book_, and Chambers's _Book of
+Days_.
+
+  AUTHORITIES.--Bingham, _Antiquities of the Christian Church_; Bede,
+  _Ecclesiastical History of England_; Procter and Frere, _A New History
+  of the Book of Common Prayer_ (London, 1901); Surtees Society, _Rites
+  of Durham_, ed. J.T. Fowler (1903); De Morgan, _Companion to the
+  Almanac_ (1845); De Moleon, _Voyages liturgiques_ (Paris, 1718).
+       (T. M. F.)
+
+
+
+
+EASTER ISLAND (Rapanui, i.e. Great Rapa), an island in the eastern part
+of the South Pacific ocean, belonging to Chile (since 1888), in 27° 8'
+S. and 109° 28' W., 1400 m. E. of Pitcairn, and 2000 m. from the South
+American coast. It is roughly triangular in shape, with its hypotenuse
+12 m. long running north-east and south-west, and its three angles
+marked by three volcanic peaks, of which the north-eastern reaches 1768
+ft. of altitude. The area of the island is 45 sq. m. The coast has no
+good natural harbour, and landing is difficult. There is no lack of
+fertile soil, and the climate is moist enough to make up for the absence
+of running water. Formerly the island appears to have been wooded, but
+it now presents only a few bushes (_Edwardsia_, _Broussonetia_, &c.),
+ferns, grasses, sedges, &c. The natives grow bananas in the shelter of
+artificial pits, also sugar-canes and sweet potatoes, and keep a few
+goats and a large stock of domestic fowls, and a Tahitian commercial
+house breeds cattle and sheep on the island.
+
+It is doubtful whether Rapanui was discovered by Davis in 1686, though
+it is sometimes marked Davis Island on maps. Admiral Roggeveen reached
+it on Easter day 1722; in 1774 Captain Cook discovered it anew and
+called it Teapi or Waihu. It was subsequently visited by La Pérouse
+(1776), Kotzebue (1816), &c. At the time of Roggeveen's discovery the
+island probably contained from 2000 to 3000 inhabitants of Polynesian
+race, who, according to their own tradition, came from Rapa Iti (Little
+Rapa) or Oparo, one of the Tubuai or Austral group. In 1863 a large
+proportion of the inhabitants were kidnapped by the Peruvians and
+transported to work at the guano diggings on the Chincha Islands. The
+next year a Jesuit mission from Tahiti reached the island and succeeded
+in the task of civilization. The natives, who number scarcely one
+hundred, are all Christians.
+
+Easter Island is famous for its wonderful archaeological remains. Here
+are found immense platforms built of large cut stones fitted together
+without cement. They are generally built upon headlands, and on the
+slope towards the sea. The walls on the seaside are, in some of the
+platforms, nearly 30 ft. high and from 200 to 300 ft. long, by about 30
+ft. wide. Some of the squared stones are as much as 6 ft. long. On the
+land side of the platforms there is a broad terrace with large stone
+pedestals upon which once stood colossal stone images carved somewhat
+into the shape of the human trunk. On some of the platforms there are
+upwards of a dozen images, now thrown from their pedestals and lying in
+all directions. Their usual height is from 14 to 16 ft., but the largest
+are 37 ft., while some are only about 4 ft. They are formed from a grey
+trachytic lava found at the east end of the island. The top of the heads
+of the images is cut flat to receive round crowns made of a reddish
+vesicular tuff found at a crater about 8 m. distant from the quarry
+where the images were cut. A number of these crowns still lie at the
+crater apparently ready for removal, some of the largest being over 10
+ft. in diameter. In the atlas illustrating the voyage of La Pérouse a
+plan of the island is given, with the position of several of the
+platforms. Two of the images are also represented in a plate. One
+statue, 8 ft. in height and weighing 4 tons, was brought to England, and
+is now in the British Museum. In one part of the island are the remains
+of stone houses nearly 100 ft. long by about 20 ft. wide. These are
+built in courses of large flat stones fitted together without cement,
+the walls being about 5 ft. thick and over 5 ft. high. They are lined on
+the inside with upright slabs, on which are painted geometrical figures
+and representations of animals. The roofs are formed by placing slabs so
+that each course overlaps the lower one until the opening becomes about
+5 ft. wide, when it is covered with flat slabs reaching from one side to
+the other. The lava rocks near the houses are carved into the
+resemblance of various animals and human faces, forming, probably, a
+kind of picture writing. Wooden tablets covered with various signs and
+figures have also been found. The only ancient implement discovered on
+the island is a kind of stone chisel, but it seems impossible that such
+large and numerous works could have been executed with such a tool. The
+present inhabitants of Easter Island know nothing of the construction of
+these remarkable works; and the entire subject of their existence in
+this small and remote island is a mystery.
+
+
+
+
+EASTERN BENGAL AND ASSAM, a province of British India, which was
+constituted out of Assam and the eastern portion of Bengal on the 16th
+of October 1905. Area 111,569 sq. m.; pop. (1901) 30,961,459. It is
+situated between 20° 45' and 28° 17' N., and between 87° 48' and 97° 5'
+E. The province, as thus reconstituted, consists of the Bengal districts
+of Dacca, Mymensingh, Faridpur, Backergunje, Tippera, Noakhali,
+Chittagong, Chittagong Hill Tracts, Rajshahi, Dinajpur, Jalpaiguri,
+Rangpur, Bogra, Pabna, Malda, and the native states of Kuch Behar and
+Hill Tippera; and the whole of the former area of Assam consisting of
+the districts of Goalpara, Kamrup, Darrang, Nowgong, Sibsagar,
+Lakhimpur, Sylhet, Cachar, Garo Hills, Khasi and Jaintia Hills, Naga
+Hills and Lushai Hills. It is bounded on the N. by Bhutan, on the W. by
+Burma, on the S. by Burma and the Bay of Bengal, and on the E. by
+Bengal. The line of demarcation between Bengal and the new province
+begins at the frontier of Bhutan, east of Darjeeling, runs south-west to
+Sahibganj on the Ganges and thence follows the course of the Ganges down
+to the deltaic branch, called the Haringhata, which leaves the main
+stream above Goalanda, and the course of the latter, which runs south
+into the Bay of Bengal. The capital of the province is Dacca, and its
+chief port is Chittagong.
+
+The Bengal districts which were transferred to Eastern Bengal and Assam
+comprised northern and eastern Bengal, the most prosperous and least
+overcrowded portion of Bengal. The land there is less densely populated,
+wages are higher and food cheaper, and the rainfall more copious and
+more regular, while the staple crops of jute, tobacco and rice command a
+higher price relative to the rent of the land than in Behar or other
+parts of Bengal. The population are largely Mahommedans and of a more
+virile stock than the Bengali proper. Northern Bengal corresponds almost
+exactly with the Rajshahi division and lies within the boundaries of the
+Ganges and Brahmaputra rivers. It contains much high land of a stiff red
+clay, with an undulating surface covered for the most part with scrub
+jungle. The inhabitants are Indo-Chinese, not Indo-Aryans as in Bengal
+proper, and are Mahommedan by religion instead of Hindu. Eastern Bengal
+consists of the Dacca and Chittagong divisions which are mainly Bengali
+in race and Hindu in religion. For the Assamese districts see ASSAM. The
+province as a whole contains 18,036,688 Mahommedans and 12,036,538
+Hindus. In language 27,272,895 of the inhabitants speak Bengali,
+1,349,784 speak Assamese, and the remainder Hindi and various hill
+dialects, Manipuri, Bodo, Khasi and Garo. The administration is in the
+hands of a lieutenant-governor, assisted by a legislative council of
+fifteen members. Under him are five commissioners, and financial matters
+are regulated by a board of revenue consisting of two members.
+
+The constitution of the new province arose out of the fact that Bengal
+had grown too unwieldy for the administration of a single
+lieutenant-governor. In 1868 Sir Stafford Northcote drew attention to
+the greatly augmented demands that the outlying portions of Bengal made
+on the time and labour of the government. At that time the population of
+the province was between 40 and 50 millions, and the question was left
+in abeyance until 1903, when the population had risen to 78½ millions.
+In the meantime the importance of rendering Assam a self-contained and
+independent administration with a service of its own, and of providing
+for its future commercial expansion, had arisen. These two
+considerations led Lord Curzon to propose that Bengal should be lopped
+of territory both on its eastern and western borders, and that all the
+districts east of the Brahmaputra should be constituted into a separate
+province. This proposal was bitterly opposed by the Hindus of Bengal on
+the ground that it would destroy the unity of the Bengali race; and
+their agitation was associated with the _Swadeshi_ (own country)
+movement for the boycott of British goods.
+
+After the constitution of the province in October 1905, the agitation in
+Eastern Bengal increased. Public meetings of protest were held,
+vernacular broadsheets containing scandalous attacks on the British
+authorities were circulated, schoolboys and others were organized and
+drilled as so-called "national volunteers," and employed as pickets to
+prevent the sale of British goods. Such was the state of things when Sir
+J. Bampfylde Fuller entered on his office as first lieutenant-governor
+of Eastern Bengal in January 1906. His reception was ominous.
+Representative bodies that were dominated by Hindus refused to vote the
+usual addresses of welcome, and non-official Hindus abstained from
+paying the customary calls. There were, however, no further overt signs
+of objection to the lieutenant-governor personally, and after a month or
+two--in spite of, or perhaps because of, his efforts to restrain
+sedition and to keep discipline in the schools--there was a decided
+change in the attitude of Hindu opinion. At Dacca, in July, for
+instance, the reception at Government House was attended by large
+numbers of Bengali gentlemen, who assured the lieutenant-governor that
+"the trouble was nearly ended." The agitation was, in fact, largely
+artificial, the work of Calcutta lawyers, journalists and schoolmasters;
+the mass of the people, naturally law-abiding, was unmoved by it so long
+as the government showed a firm hand; while the Mussulmans, who formed a
+large proportion of the whole, saw in the maintenance of the partition
+and of the prestige of the British government the guarantees of their
+own security.
+
+All seemed to be going well when an unfortunate difference of opinion
+occurred between the lieutenant-governor and the central government,
+resulting in the resignation of Sir Bampfylde Fuller (August 1906) and
+in ulterior consequences destined to be of far-reaching import. The
+facts are briefly as follows. Acting on a report of Dr P. Chatterji,
+inspector of schools, dated January 2, 1906, the lieutenant-governor, on
+the 10th of February, addressed a letter to the registrar of Calcutta
+University recommending that the privilege of affiliation to the
+university should be withdrawn from the Banwarilal and Victoria high
+schools at Sirajganj in Pabna, as a punishment for the seditious conduct
+of both pupils and teachers. Apart from numerous cases of illegal
+interference with trade and of disorder in the streets reported against
+the students, two specific outrages of a serious character were
+instanced as having occurred on the 15th of November: the raiding of a
+cart laden with English cloth belonging to Marwari traders, and a
+cowardly assault by some 40 or 50 lads on the English manager of the
+Bank of Bengal. These outrages "were not the result of thoughtlessness
+or sudden excitement, but were the outcome of a regularly organized
+scheme, set on foot and guided by the masters of these schools, for
+employing the students in enforcing a boycott." All attempts to discover
+and punish the offenders had been frustrated by the refusal of the
+school authorities to take action, and in the opinion of the
+lieutenant-governor the only course open was to apply the remedy
+suggested in the circular letter addressed to magistrates and collectors
+(October 10, 1905) by Mr R.W. Carlyle, the officiating chief secretary
+to the government of Bengal, directing them, in the event of students
+taking any part in political agitation, boycotting and the like, to
+inform the heads of schools or colleges concerned that, unless they
+prevented such action being taken by the boys attending their
+institutions, their grant-in-aid and the privilege of competing for
+scholarships and of receiving scholarship-holders would be withdrawn,
+and that the university would be asked to disaffiliate their
+institutions.
+
+The reply, dated July 5th, from the secretary in the home department of
+the government of India, was--to use Sir Bampfylde's own later
+expression--to throw him over. It was likely that a difference of
+opinion in the syndicate of the university would arise as to the degree
+of culpability that attached to the proprietors of the schools; in the
+event of the syndicate taking any "punitive action," the matter was
+certain to be raised in the senate, and would lead to an acrimonious
+public discussion, in which the partition of Bengal and the
+administration of the new province would be violently attacked; and in
+the actual state of public opinion in Bengal it seemed to the government
+of India highly inexpedient that such a debate should take place.
+"Collective punishment," too, "would be liable to be misconstrued in
+England," and the government preferred to rely on the gradual effect of
+the new university regulations, which aimed "at discouraging the
+participation of students in political movements by enforcing the
+responsibility of masters and the managing committees of schools for
+maintaining discipline."
+
+On receipt of this communication Sir Bampfylde Fuller at once tendered
+his resignation to the viceroy (July 15). He pointed out that to
+withdraw from the position taken up would be "concession, not in the
+interests of education, but to those people in Calcutta who have been
+striving to render my government impossible, in order to discredit the
+partition"; that previous concessions had had merely provocative
+effects, and that were he to give way in this matter his authority would
+be so weakened that he would be unable to maintain order in the country.
+On the 3rd of August, after some days of deliberation, the viceroy
+telegraphed saying that he was "unable to reconsider the orders sent,"
+and accepting Sir Bampfylde's resignation. By the Anglo-Indian press the
+news was received with something like consternation, the _Times of
+India_ describing the resignation as one of the gravest blunders ever
+committed in the history of British rule in India, and as a direct
+incentive to the forces of disquiet, disturbance and unrest. Equally
+emphatic was the verdict of the Mussulman community forming two-thirds
+of the population of Eastern Bengal. On the 7th of August, the day of
+Sir Bampfylde Fuller's departure from Dacca, a mass-meeting of 30,000
+Mahommedans was held, which placed on record their disapproval of a
+system of government "which maintains no continuity of policy," and
+expressed its feeling that the lowering of British prestige must
+"alienate the sympathy of a numerically important and loyal section of
+His Majesty's subjects"; and many meetings of Mussulmans subsequently
+passed resolutions to the same general effect. The _Akhbar-i-Islam_, the
+organ of Bombay Mussulman opinion, deplored the "unwise step" taken by
+the government, and ascribed it to Lord Minto's fear of the Babu press,
+a display of weakness of which the Babus would not be slow to take
+advantage.
+
+This latter prophecy was not slow in fulfilling itself. So early as the
+8th of August Calcutta was the scene of several large demonstrations at
+which the Swadeshi vow was renewed, and at which resolutions were passed
+declining to accept the partition as a settled fact, and resolving on
+the continuance of the agitation. The tone of the Babu press was openly
+exultant: "We have read the familiar story of the Russian traveller and
+the wolves," said a leading Indian newspaper in Calcutta. "The British
+government follows a similar policy. First the little babies were
+offered up in the shape of the _Bande Mataram_ circular and the Carlyle
+circular. Now a bigger boy has gone in the person of our own Joseph.
+Courage, therefore, O wolves! Press on and the horse will soon be yours
+to devour! Afterwards the traveller himself will alone be left."[1] The
+task before the new lieutenant-governor of Eastern Bengal, the Hon. L.
+Hare, was obviously no easy one. The encouragement given to sedition by
+the weakness of the government in this case was shown by later events in
+Bengal and elsewhere (see INDIA: _History, ad fin._).
+
+For the early history of the various portions of the province see BENGAL
+and ASSAM.
+
+  See Sir James Bourdillon, _The Partition of Bengal_ (Society of Arts,
+  1905); official blue-books on _The Reconstitution of the Provinces of
+  Bengal and Assam_ (Cd. 2658 and 2746), and _Resignation of Sir J.
+  Bampfylde Fuller_, lieutenant-governor, &c. (Cd. 3242). A long letter
+  from Sir J.B. Fuller, headed _J'accuse_, attacking the general policy
+  of the Indian government in regard to the seditious propaganda,
+  appeared in _The Times_ of June 6, 1908.
+
+
+FOOTNOTE:
+
+  [1] Quoted by Mr F.S.P. Lely in _The Times_ of November 22, 1906.
+
+
+
+
+EASTERN QUESTION, THE, the expression used in diplomacy from about the
+time of the congress of Verona (1822) to comprehend the international
+problems involved in the decay of the Turkish empire and its supposed
+impending dissolution. The essential questions that are involved are so
+old that historians commonly speak of the "Eastern Question" in
+reference to events that happened long before the actual phrase was
+coined. But, wherever used, it is always the Turkish Question, the
+generic term in which subsidiary issues, e.g. the Greek, Armenian or
+Macedonian questions, are embraced. That a phrase of so wide and loose a
+nature should have been stereotyped in so narrow a sense is simply the
+outcome of the conditions under which it was invented. To the European
+diplomatists of the first half of the 19th century the Ottoman empire
+was still the only East with which they were collectively brought into
+contact. The rivalry of Great Britain and Russia in Persia had not yet
+raised the question of the Middle East; still less any ambitions of
+Germany in the Euphrates valley. The immense and incalculable problems
+involved in the rise of Japan, the awakening of China, and their
+relations to the European powers and to America--known as the Far
+Eastern Question--are comparatively but affairs of yesterday.
+
+The Eastern Question, though its roots are set far back in history--in
+the ancient contest between the political and intellectual ideals of
+Greece and Asia, and in the perennial rivalry of the powers for the
+control of the great trade routes to the East--dates in its modern sense
+from the treaty of Kuchuk Kainarji in 1774, which marked the definitive
+establishment of Russia as a Black Sea power and formed the basis of her
+special claims to interfere in the affairs of the Ottoman empire. The
+compact between Napoleon and the emperor Alexander I. at Tilsit (1807)
+marked a new phase, which culminated in 1812 in the treaty of Bucharest,
+in which Russia definitely appeared as the protector of the Christian
+nationalities subject to the Ottoman sultan.
+
+The attitude of the various powers in the Eastern Question was now
+defined. Russia, apart from her desire to protect the Orthodox
+nationalities subject to the Ottoman power, aimed at owning or
+controlling the straits by which alone she could find an outlet to the
+Mediterranean and the ocean beyond. Austria, once the champion of Europe
+against the Turk, saw in the Russian advance on the Danube a greater
+peril than any to be feared from the moribund Ottoman power, and made
+the maintenance of the integrity of Turkey a prime object of her policy.
+She was thus brought into line with Great Britain, whose traditional
+friendship with Turkey was strengthened by the rise of a new power whose
+rapid advance threatened the stability of British rule in India. But
+though Austria, Great Britain and presently France, were all equally
+interested in maintaining the Ottoman empire, the failure of the
+congress of Vienna in 1815 to take action in the matter of a guarantee
+of Turkey, and the exclusion of the Sultan from the Holy Alliance,
+seemed to endorse the claim of Russia to regard the Eastern Question as
+"her domestic concern" in which "Europe" had no right to interfere. The
+revolt of the Greeks (1821) put this claim to the test; by the treaty of
+Adrianople (1829) Russia stipulated for their autonomy as part of the
+price of peace, but the powers assembled in conference at London refused
+to recognize this settlement, and the establishment of Greece as an
+independent kingdom (1832) was really aimed at the pretensions and the
+influence of Russia. These reached their high-water mark in the treaty
+of Unkiar Skelessi (July 8th, 1832). It was no longer a question of the
+partition of Turkey or of a Russian conquest of Constantinople, but of
+the deliberate degradation by Russia of the Ottoman empire into a weak
+state wholly dependent upon herself. The ten years' crisis (1831-1841)
+evoked by the revolt of Mehemet Ali, pasha of Egypt, thus resolved
+itself into a diplomatic struggle between Russia and the other powers to
+maintain or to recover influence at Constantinople. The Russian
+experiment of maintaining the integrity of Turkey while practically
+treating her as a vassal state, ended with the compromise of 1841; and
+the emperor Nicholas I. reverted to the older idea of expelling the
+Turks from Europe. The Eastern Question, however, slumbered until, in
+1851, the matter of the Holy Places was raised by Napoleon III.,
+involving the whole question of the influence in Ottoman affairs of
+France under the capitulations of 1740 and of Russia under the treaty of
+1774. The Crimean War followed and in 1856 the treaty of Paris, by which
+the powers hoped to stem the tide of Russian advance and establish the
+integrity of a reformed Ottoman state. Turkey was now for the first
+time solemnly admitted to the European concert. The next critical phase
+was opened in 1871, when Russia took advantage of the collapse of France
+to denounce the Black Sea clauses of the treaty of 1856. The renewal of
+an aggressive policy thus announced to the world soon produced a new
+crisis in the Eastern Question, which had meanwhile become complicated
+by the growth of Pan-Slav ideals in eastern Europe. In 1875 a rising in
+Herzegovina gave evidence of a state of feeling in the Balkan peninsula
+which called for the intervention of Europe, if a disastrous war were to
+be prevented. But this intervention, embodied in the "Andrassy Note"
+(December 1875) and the Berlin memorandum (May 1876), met with the
+stubborn opposition of Turkey, where the "young Turks" were beginning to
+oppose a Pan-Islamic to the Pan-Slav ideal. The Russo-Turkish War of
+1877-78 followed, concluded by the treaty of San Stefano, the terms of
+which were modified in Turkey's favour by the congress of Berlin (1878),
+which marks the beginning of the later phase of the Eastern Question.
+Between Russia and Turkey it interposed, in effect, a barrier of
+independent (Rumania, Servia) and quasi-independent (Bulgaria) states,
+erected with the counsel and consent of collective Europe. It thus,
+while ostensibly weakening, actually tended to strengthen the Ottoman
+power of resistance.
+
+The period following the treaty of Berlin is coincident with the reign
+of Sultan Abd-ul-Hamid II. The international position of the Ottoman
+empire was strengthened by the able, if Machiavellian, statecraft of the
+sultan; while the danger of disruption from within was lessened by the
+more effective central control made possible by railways, telegraphs,
+and the other mechanical improvements borrowed from western
+civilization. With the spread of the Pan-Islamic movement, moreover, the
+undefined authority of the sultan as caliph of Islam received a fresh
+importance even in countries beyond the borders of the Ottoman empire,
+while in countries formerly, or nominally still, subject to it, it
+caused, and promised to cause, incalculable trouble.
+
+The Eastern Question thus developed, in the latter years of the 19th
+century, from that of the problems raised by the impending break-up of a
+moribund empire, into the even more complex question of how to deal with
+an empire which showed vigorous evidence of life, but of a type of life
+which, though on all sides in close touch with modern European
+civilization, was incapable of being brought into harmony with it. The
+belief in the imminent collapse of the Ottoman dominion was weakened
+almost to extinction; so was the belief, which inspired the treaty of
+1856, in the capacity of Turkey to reform and develop itself on European
+lines. But the Ottoman empire remained, the mistress of vast undeveloped
+wealth. The remaining phase of the Eastern Question, if we except the
+concerted efforts to impose good government on Macedonia in the
+interests of European peace, or the side issues in Egypt and Arabia, was
+the rivalry of the progressive nations for the right to exploit this
+wealth. In this rivalry Germany, whose interest in Turkey even so late
+as the congress of Berlin had been wholly subordinate, took a leading
+part, unhampered by the traditional policies or the humanitarian
+considerations by which the interests of the older powers were
+prejudiced. The motives of German intervention in the Eastern Question
+were ostensibly commercial; but the Bagdad railway concession,
+postulating for its ultimate success the control of the trade route by
+way of the Euphrates valley, involved political issues of the highest
+moment and opened up a new and perilous phase of the question of the
+Middle East.
+
+This was the position when in 1908 an entirely new situation was created
+by the Turkish revolution. As the result of the patient and masterly
+organization of the "young Turks," combined with the universal
+discontent with the rule of the sultan and the palace _camarilla_, the
+impossible seemed to be achieved, and the heterogeneous elements
+composing the Ottoman empire to be united in the desire to establish a
+unified state on the constitutional model of the West. The result on the
+international situation was profound. Great Britain hastened to re-knit
+the bonds of her ancient friendship with Turkey; the powers, without
+exception, professed their sympathy with the new régime. The
+establishment of a united Turkey on a constitutional and nationalist
+basis was, however, not slow in producing a fresh complication in the
+Eastern Question. Sooner or later the issue was sure to be raised of the
+status of those countries, still nominally part of the Ottoman empire,
+but in effect independent, like Bulgaria, or subject to another state,
+like Bosnia and Herzegovina. The cutting of the Gordian knot by
+Austria's annexation of Bosnia and Herzegovina, and by the proclamation
+of the independence of Bulgaria, and of Prince Ferdinand's assumption of
+the old title of tsar (king), threatened to raise the Eastern Question
+once more in its acutest form. The international concert defined in the
+treaty of Berlin had been rudely shaken, if not destroyed; the
+denunciation by Austria, without consulting her co-signatories, of the
+clauses of the treaty affecting herself seemed to invalidate all the
+rest; and in the absence of the restraining force of a united concert of
+the great powers, free play seemed likely once more to be given to the
+rival ambitions of the Balkan nationalities, the situation being
+complicated by the necessity for the dominant party in the renovated
+Turkish state to maintain its prestige. During the anxious months that
+followed the Austrian _coup_, the efforts of diplomacy were directed to
+calming the excitement of Servians, Montenegrins and the Young Turks,
+and to considering a European conference in which the _fait accompli_
+should be regularized in accordance with the accepted canons of
+international law. The long delay in announcing the assembly of the
+conference proved the extreme difficulty of arriving at any satisfactory
+basis of settlement; and though the efforts of the powers succeeded in
+salving the wounded pride of the Turks, and restraining the impetuosity
+of the Serbs and Montenegrins, warlike preparations on the part of
+Austria continued during the winter of 1908-1909, being justified by the
+agitation in Servia, Montenegro and the annexed provinces. It was not
+till April 1909 (see EUROPE: ad fin.) that the crisis was ended, through
+the effectual backing given by Germany to Austria; and Russia, followed
+by England and France, gave way and assented to what had been done.
+
+  See TURKEY: _History_, where cross-references to the articles on the
+  various phases of the Eastern Question will be found, together with a
+  bibliography. See also E. Driault, _La Question d'orient depuis son
+  origine_ (Paris, 1898), a comprehensive sketch of the whole subject,
+  including the Middle and Far East.     (W. A. P.)
+
+
+
+
+EAST GRINSTEAD, a market town in the East Grinstead parliamentary
+division of Sussex, England, 30 m. S. by E. from London by the London,
+Brighton & South Coast railway. Pop. of urban district (1901) 6094. St
+Swithin's church contains, among numerous ancient memorials, one of the
+iron memorial slabs (1507) peculiar to certain churches of Sussex, and
+recalling the period when iron was extensively worked in the district.
+There may be noticed Sackville College (an almshouse founded in 1608),
+and St Margaret's home and orphanage, founded by the Rev. John Mason
+Neale (1818-1866), warden of Sackville College. Brewing and brick and
+tile making are carried on. In the vicinity (near Forest Row station) is
+the golf course of the Royal Ashdown Forest Golf Club.
+
+The hundred of East Grinstead (Grenestede, Estgrensted) was in the
+possession of the count of Mortain in 1086, but no mention of a vill or
+manor of East Grinstead is made in the Domesday Survey. In the reign of
+Henry III. the hundred was part of the honour of Aquila, then in the
+king's hands. The honour was granted by him to Peter of Savoy, through
+whom it passed to his niece Queen Eleanor. In the next reign the king's
+mother held the borough of East Grinstead as parcel of the honour of
+Aquila. East Grinstead was included in a grant by Edward III. to John of
+Gaunt, duke of Lancaster, and it remained part of the duchy of Lancaster
+until James I. granted the borough to Sir George Rivers, through whom it
+was obtained by the Sackvilles, earls of Dorset. East Grinstead was a
+borough by prescription. In the 16th century it was governed by an
+alderman, bailiff and constable. It returned two members to parliament
+from 1307 until 1832, but was disenfranchised by the Reform Act. In 1285
+the king ordered that his market at Grenestede should be held on
+Saturday instead of Sunday, and in 1516 the inhabitants of the town were
+granted a market each week on Saturday and a fair every year on the eve
+of St Andrew and two days following. Charles I. granted the earl of
+Dorset a market on Thursday instead of the Saturday market, and fairs on
+the 16th of April and the 26th of September every year. Thursday is
+still the market-day, and cattle-fairs are now held on the 21st of April
+and the 11th of December.
+
+
+
+
+EAST HAM, a municipal borough in the southern parliamentary division of
+Essex, England, contiguous to West Ham, and thus forming geographically
+part of the eastward extension of London. Pop. (1901) 96,018. Its modern
+growth has been very rapid, the population being in the main of the
+artisan class. There are some chemical and other factories. The ancient
+parish church of St Mary Magdalen retains Norman work in the chancel,
+which terminates in an eastern apse. There is a monument for Edmund
+Neville who claimed the earldom of Westmorland in the 17th century, and
+William Stukeley, the antiquary, was buried in the churchyard. East Ham
+was incorporated in 1904, and among its municipal undertakings is a
+technical college (1905). The corporation consists of a mayor, 6
+aldermen and 18 councillors. Area, 3320½ acres.
+
+
+
+
+EASTHAMPTON, a township of Hampshire county, Mass., U.S.A., in the
+Connecticut Valley. Pop. (1900) 5603, of whom 1731 were foreign-born;
+(1905) 6808; (1910) 8524. It is served by the Boston & Maine, and the
+New York, New Haven & Hartford railways, and by interurban electric
+railways. The township is generally level, and is surrounded by high
+hills. In Easthampton are a free public library and Williston Seminary;
+the latter, one of the oldest and largest preparatory schools in New
+England, was founded in 1841 by the gifts of Samuel Williston
+(1795-1874) and Emily Graves Williston (1797-1885). Mr and Mrs Williston
+built up the industry of covering buttons with cloth, at first doing the
+work by hand, then (1827) experimenting with machinery, and in 1848
+building a factory for making and covering buttons. As the soil was
+fertile and well watered, the township had been agricultural up to this
+time. It is now chiefly devoted to manufacturing. Among its products are
+cotton goods, especially mercerised goods, for the manufacture of which
+it has one of the largest plants in the country; rubber, thread, elastic
+fabrics, suspenders and buttons. Parts of Northampton and Southampton
+were incorporated as the "district" of Easthampton in 1785; it became a
+township in 1809, and in 1841 and 1850 annexed parts of Southampton.
+
+
+
+
+EAST HAMPTON, a township of Suffolk county, New York, in the extreme
+S.E. part of Long Island, occupying the peninsula of Montauk, and
+bounded on the S. and E. by the Atlantic Ocean, and on the N. by Block
+Island Sound, Gardiner's Bay and Peconic Bay. Pop. (1900) 3746; (1905)
+4303; (1910) 4722. The township, 25 m. long and 8 m. at its greatest
+width from north to south, has an irregular north coast-line and a very
+regular south coast-line. The surface is rougher to the west where there
+are several large lakes, notably Great Pond, 2 m. long. The scenery is
+picturesque and the township is much frequented by artists. Montauk
+Lighthouse, on Turtle Hill, was first built in 1795. At Montauk, after
+the Spanish-American War, was Camp Wikoff, a large U.S. military camp.
+The township is served by the southern division of the Long Island
+railway, the terminus of which is Montauk. Other villages of the
+township, all summer resorts, are: Promised Land, Amagansett, East
+Hampton and Sag Harbor; the last named, only partly in the township, was
+incorporated in 1803 and had a population of 1969 in 1900, and 3084 in
+1910. Silverware and watch cases are manufactured here. From Sag Harbor,
+which is a port of entry, a daily steamer runs to New York city. The
+village received many gifts in 1906-1908 from Mrs Russell Sage. Most of
+the present township was bought from the Indians (Montauks, Corchaugs
+and Shinnecocks) in 1648 for about £30, through the governors of
+Connecticut and New Haven, by nine Massachusetts freemen, mostly
+inhabitants of Lynn, Massachusetts. With twenty other families they
+settled here in 1649, calling the place Maidstone, from the old home of
+some of the settlers in Kent; but as early as 1650 the name East Hampton
+was used in reference to the earlier settlement of South Hampton. Until
+1664, when all Long Island passed to the duke of York, the government
+was by town meeting, autonomous and independent except for occasional
+appeals to Connecticut. In 1683 Gardiner's Island, settled by Lion
+Gardiner in 1639 and so one of the first English settlements in what is
+now New York state, was made a part of Long Island and of East Hampton
+township. The English settlements in East Hampton were repeatedly
+threatened by pirates and privateers, and there are many stories of
+treasure buried by Captain Kidd on Gardiner's Island and on Montauk
+Point. The Clinton Academy, opened in East Hampton village in 1785, was
+long a famous school. Of the church built here in 1653 (first
+Congregational and after 1747 Presbyterian in government), Lyman Beecher
+was pastor in 1799-1810; and in East Hampton were born his elder
+children. Whale fishing was begun in East Hampton in 1675, when four
+Indians were engaged by whites in off-shore whaling; but Sag Harbor,
+which was first settled in 1730 and was held by the British after the
+battle of Long Island as a strategic naval and shipping point, became
+the centre of the whaling business. The first successful whaling voyage
+was made from Sag Harbor in 1785, and although the Embargo ruined the
+fishing for a time, it revived during 1830-1850. Cod and menhaden
+fishing, the latter for the manufacture of fish-oil and guano, were
+important for a time, but in the second half of the 19th century Sag
+Harbor lost its commercial importance.
+
+
+
+
+EAST INDIA COMPANY, an incorporated company for exploiting the trade
+with India and the Far East. In the 17th and 18th centuries East India
+companies were established by England, Holland, France, Denmark,
+Scotland, Spain, Austria and Sweden. By far the most important of these
+was the English East India Company, which became the dominant power in
+India, and only handed over its functions to the British Government in
+1858 (see also DUTCH EAST INDIA COMPANY, OSTEND COMPANY).
+
+
+  English East India Co.
+
+The English East India Company was founded at the end of the 16th
+century in order to compete with the Dutch merchants, who had obtained a
+practical monopoly of the trade with the Spice Islands, and had raised
+the price of pepper from 3s. to 8s. per lb. Queen Elizabeth incorporated
+it by royal charter, dated December 31, 1600, under the title of "The
+Governor and Company of Merchants of London, trading into the East
+Indies." This charter conferred the sole right of trading with the East
+Indies, i.e. with all countries lying beyond the Cape of Good Hope or
+the Straits of Magellan, upon the company for a term of 15 years.
+Unauthorized interlopers were liable to forfeiture of ships and cargo.
+There were 125 shareholders in the original East India Company, with a
+capital of £72,000: the first governor was Sir Thomas Smythe. The early
+voyages of the company, from 1601 to 1612, are distinguished as the
+"separate voyages," because the subscribers individually bore the cost
+of each voyage and reaped the whole profits, which seldom fell below
+100%. After 1612 the voyages were conducted on the joint stock system
+for the benefit of the company as a whole. These early voyages, whose
+own narratives may be read in Purchas, pushed as far as Japan, and
+established friendly relations at the court of the Great Mogul. In
+1610-1611 Captain Hippon planted the first English factories on the
+mainland of India, at Masulipatam and at Pettapoli in the Bay of Bengal.
+The profitable nature of the company's trade had induced James I. to
+grant subsidiary licences to private traders; but in 1609 he renewed the
+company's charter "for ever," though with a proviso that it might be
+revoked on three years' notice if the trade should not prove profitable
+to the realm.
+
+
+  English and Dutch disputes.
+
+Meanwhile friction was arising between the English and Dutch East India
+Companies. The Dutch traders considered that they had prior rights in
+the Far East, and their ascendancy in the Indian Archipelago was indeed
+firmly established on the basis of territorial dominion and authority.
+In 1613 they made advances to the English company with a suggestion for
+co-operation, but the offer was declined, and the next few years were
+fertile in disputes between the armed traders of both nations. In 1619
+was ratified a "treaty of defence" to prevent disputes between the
+English and Dutch companies. When it was proclaimed in the East,
+hostilities solemnly ceased for the space of an hour, while the Dutch
+and English fleets, dressed out in all their flags and with yards
+manned, saluted each other; but the treaty ended in the smoke of that
+stately salutation, and perpetual and fruitless contentions between the
+Dutch and English companies went on just as before. In 1623 these
+disputes culminated in the "massacre of Amboyna," where the Dutch
+governor tortured and executed the English residents on a charge of
+conspiring to seize the fort. Great and lasting indignation was aroused
+in England, but it was not until the time of Cromwell that some
+pecuniary reparation was exacted for the heirs of the victims. The
+immediate result was that the English company tacitly admitted the Dutch
+claims to a monopoly of the trade in the Far East, and confined their
+operations to the mainland of India and the adjoining countries.
+
+
+  The East Indiamen.
+
+The necessity of good ships for the East Indian trade had led the
+company in 1609 to construct their dockyard at Deptford, from which, as
+Monson observes, dates "the increase of great ships in England." Down to
+the middle of the 19th century, the famous "East Indiamen" held
+unquestioned pre-eminence among the merchant vessels of the world.
+Throughout the 17th century they had to be prepared at any moment to
+fight not merely Malay pirates, but the armed trading vessels of their
+Dutch, French and Portuguese rivals. Many such battles are recorded in
+the history of the East India Company, and usually with successful
+results.
+
+
+  The acquisition of territory.
+
+It was not until it had been in existence for more than a century that
+the English East India Company obtained a practical monopoly of the
+Indian trade. In 1635, a year after the Great Mogul had granted it the
+liberty of trading throughout Bengal, Charles I. issued a licence to
+Courten's rival association, known as "the Assada Merchants," on the
+ground that the company had neglected English interests. The piratical
+methods of their rivals disgraced the company with the Mogul officials,
+and a _modus vivendi_ was only reached in 1649. In 1657 Cromwell renewed
+the charter of 1609, providing that the Indian trade should be in the
+hands of a single joint stock company. The new company thus formed
+bought up the factories, forts and privileges of the old one. It was
+further consolidated by the fostering care of Charles II., who granted
+it five important charters. From a simple trading company, it grew under
+his reign into a great chartered company--to use the modern term--with
+the right to acquire territory, coin money, command fortresses and
+troops, form alliances, make war and peace, and exercise both civil and
+criminal jurisdiction. It is accordingly in 1689, when the three
+presidencies of Bengal, Madras and Bombay had lately been established,
+that the ruling career of the East India Company begins, with the
+passing by its directors of the following resolution for the guidance of
+the local governments in India:--"The increase of our revenue is the
+subject of our care, as much as our trade; 'tis that must maintain our
+force when twenty accidents may interrupt our trade; 'tis that must make
+us a nation in India; without that we are but a great number of
+interlopers, united by His Majesty's royal charter, fit only to trade
+where nobody of power thinks it their interest to prevent us; and upon
+this account it is that the wise Dutch, in all their general advices
+that we have seen, write ten paragraphs concerning their government,
+their civil and military policy, warfare, and the increase of their
+revenue, for one paragraph they write concerning trade." From this
+moment the history of the transactions of the East India Company becomes
+the history of British India (see INDIA: _History_). Here we shall only
+trace the later changes in the constitution and powers of the ruling
+body itself.
+
+
+  The interlopers.
+
+The great prosperity of the company under the Restoration, and the
+immense profits of the Indian trade, attracted a number of private
+traders, both outside merchants and dismissed or retired servants of the
+company, who came to be known as "interlopers." In 1683 the case of
+Thomas Sandys, an interloper, raised the whole question of the royal
+prerogative to create a monopoly of the Indian trade. The case was tried
+by Judge Jeffreys, who upheld the royal prerogative; but in spite of his
+decision the custom of interloping continued and laid the foundation of
+many great fortunes. By 1691 the interlopers had formed themselves into
+a new society, meeting at Dowgate, and rivalling the old company; the
+case was carried before the House of Commons, which declared in 1694
+that "all the subjects of England have equal right to trade to the East
+Indies unless prohibited by act of parliament." This decision led up to
+the act of 1698, which created a new East India Company in consideration
+of a loan of two millions to the state. The old company subscribed
+£315,000 and became the dominant factor in the new body; while at the
+same time it retained its charter for three years, its factories, forts
+and assured position in India. The rivalry between the two companies
+continued both in England and in India, until they were finally
+amalgamated by a tripartite indenture between the companies and Queen
+Anne (1702), which was ratified under the Godolphin Award (1708). Under
+this award the company was to lend the nation £3,200,000, and its
+exclusive privileges were to cease at three years' notice after this
+amount had been repaid. But by this time the need for permanence in the
+Indian establishment began to be felt, while parliament would not
+relinquish its privilege of "milking" the company from time to time. In
+1712 an act was passed continuing the privileges of the company even
+after their fund should be redeemed; in 1730 the charter was prolonged
+until 1766, and in 1742 the term was extended until 1783 in return for
+the loan of a million. This million was required for the war with
+France, which extended to India and involved the English and French
+companies there in long-drawn hostilities, in which the names of Dupleix
+and Clive became prominent.
+
+
+  The company and the crown.
+
+So long as the company's chief business was that of trade, it was left
+to manage its own affairs. The original charter of Elizabeth had placed
+its control in the hands of a governor and a committee of twenty-four,
+and this arrangement subsisted in essence down to the time of George
+III. The chairman and court of directors in London exercised unchecked
+control over their servants in India. But after Clive's brilliant
+victory at Plassey (1757) had made the company a ruling power in India,
+it was felt to be necessary that the British government should have some
+control over the territories thus acquired. Lord North's Regulating Act
+(1773) raised the governor of Bengal--Warren Hastings--to the rank of
+governor-general, and provided that his nomination, though made by a
+court of directors, should in future be subject to the approval of the
+crown; in conjunction with a council of four, he was entrusted with the
+power of peace and war; a supreme court of judicature was established,
+to which the judges were appointed by the crown; and legislative power
+was conferred on the governor-general and his council. Next followed
+Pitt's India Bill (1784), which created the board of control, as a
+department of the English government, to exercise political, military
+and financial superintendence over the British possessions in India.
+This bill first authorized the historic phrase "governor-general in
+council." From this date the direction of Indian policy passed
+definitely from the company to the governor-general in India and the
+ministry in London. In 1813 Lord Liverpool passed a bill which further
+gave the board of control authority over the company's commercial
+transactions, and abolished its monopoly of Indian trade, whilst leaving
+it the monopoly of the valuable trade with China, chiefly in tea.
+Finally, under Earl Grey's act of 1833, the company was deprived of this
+monopoly also. Its property was then secured on the Indian possessions,
+and its annual dividends of ten guineas per £100 stock were made a
+charge upon the Indian revenue. Henceforward the East India Company
+ceased to be a trading concern and exercised only administrative
+functions. Such a position could not, in the nature of things, be
+permanent, and the great cataclysm of the Indian Mutiny was followed by
+the entire transference of Indian administration from the company to the
+crown, on the 2nd of August 1858.
+
+  See _Purchas his Pilgrimes_ (ed. 1905), vols. 2, 3, 4, 5, for the
+  charter of Elizabeth and the early voyages; Sir W.W. Hunter, _History
+  of British India_ (1899); Beckles Willson, _Ledger and Sword_ (1903);
+  Sir George Birdwood, _Report on the Old Records of the India Office_
+  (1879); _The East India Company's First Letter Book_ (1895), _Letters
+  Received by the East India Company from its Servants in the East_, ed.
+  Foster, (1896 ff.). See also the interesting memorial volume _Relics
+  of the Honourable East India Company_ (ed. Griggs, 1909), letterpress
+  by Sir G. Birdwood and W. Foster.
+
+
+
+
+EAST INDIES, a name formerly applied vaguely, in its widest sense, to
+the whole area of India, Further India and the Malay Archipelago, in
+distinction from the West Indies, which, at the time of their discovery,
+were taken to be the extreme parts of the Indian region. The term "East
+Indies" is still sometimes applied to the Malay Archipelago (q.v.)
+alone, and the phrase "Dutch East Indies" is commonly used to denote the
+Dutch possessions which constitute the greater part of that archipelago.
+The Dutch themselves use the term _Nederlandsch-Indië_.
+
+
+
+
+EASTLAKE, SIR CHARLES LOCK (1793-1865), English painter, was born on the
+17th of November 1793 at Plymouth, where his father, a man of uncommon
+gifts but of indolent temperament, was solicitor to the admiralty and
+judge advocate of the admiralty court. Charles was educated (like Sir
+Joshua Reynolds) at the Plympton grammar-school, and in London at the
+Charterhouse. Towards 1809, partly through the influence of his
+fellow-Devonian Haydon, of whom he became a pupil, he determined to be a
+painter; he also studied in the Royal Academy school. In 1813 he
+exhibited in the British Institution his first picture, a work of
+considerable size, "Christ restoring life to the Daughter of Jairus." In
+1814 he was commissioned to copy some of the paintings collected by
+Napoleon in the Louvre; he returned to England in 1815, and practised
+portrait-painting at Plymouth. Here he saw Napoleon a captive on the
+"Bellerophon"; from a boat he made some sketches of the emperor, and he
+afterwards painted, from these sketches and from memory, a life-sized
+full-length portrait of him (with some of his officers) which was
+pronounced a good likeness; it belongs to the marquess of Lansdowne. In
+1817 Eastlake went to Italy; in 1819 to Greece; in 1820 back to Italy,
+where he remained altogether fourteen years, chiefly in Rome and in
+Ferrara.
+
+In 1827 he exhibited at the Royal Academy his picture of the Spartan
+Isidas, who (as narrated by Plutarch in the life of Agesilaus), rushing
+naked out of his bath, performed prodigies of valour against the Theban
+host. This was the first work that attracted much notice to the name of
+Eastlake, who in consequence obtained his election as A.R.A.; in 1830,
+when he returned to England, he was chosen R.A. In 1850 he succeeded
+Shee as president of the Royal Academy, and was knighted. Prior to this,
+in 1841, he had been appointed secretary to the royal commission for
+decorating the Houses of Parliament, and he retained this post until the
+commission was dissolved in 1862. In 1843 he was made keeper of the
+National Gallery, a post which he resigned in 1847 in consequence of an
+unfortunate purchase that roused much animadversion, a portrait
+erroneously ascribed to Holbein; in 1855, director of the same
+institution, with more extended powers. During his directorship he
+purchased for the gallery 155 pictures, mostly of the Italian schools.
+He became also a D.C.L. of Oxford, F.R.S., a chevalier of the Legion of
+Honour, and member of various foreign academies.
+
+In 1849 he married Miss Elizabeth Rigby, who had already then become
+known as a writer (_Letters from the Baltic_, 1841; _Livonian Tales_,
+1846; _The Jewess_, 1848) and as a contributor to the _Quarterly
+Review_. Lady Eastlake (1809-1893) had for some years been interested in
+art subjects, and after her marriage she naturally devoted more
+attention to them, translating Waagen's _Treasures of Art in Great
+Britain_ (1854-1857), and completing Mrs Jameson's _History of our Lord
+in Works of Art_. In 1865 Sir Charles Eastlake fell ill at Milan; and he
+died at Pisa on the 24th of December in the same year. Lady Eastlake,
+who survived him for many years, continued to play an active part as a
+writer on art (_Five Great Painters_, 1883, &c.), and had a large circle
+of friends among the most interesting men and women of the day. In 1880
+she published a volume of _Letters from France_ (describing events in
+Paris during 1789), written by her father, Edward Rigby (1747-1821), a
+distinguished Norwich doctor who was known also for his practical
+interest in agriculture, and who is said to have made known the flying
+shuttle to Norwich manufacturers.
+
+As a painter, Sir Charles Eastlake was gentle, harmonious, diligent and
+correct; lacking fire of invention or of execution; eclectic, without
+being exactly imitative; influenced rather by a love of ideal grace and
+beauty than by any marked bent of individual power or vigorous
+originality. Among his principal works (which were not numerous, 51
+being the total exhibited in the Academy) are: 1828, "Pilgrims arriving
+in sight of Rome" (repeated in 1835 and 1836, and perhaps on the whole
+his _chef-d'oeuvre_); 1829, "Byron's Dream" (in the Tate Gallery); 1834,
+the "Escape of Francesco di Carrara" (a duplicate in the Tate Gallery);
+1841, "Christ Lamenting over Jerusalem" (ditto); 1843, "Hagar and
+Ishmael"; 1845, "Comus"; 1849, "Helena"; 1851, "Ippolita Torelli"; 1853,
+"Violante"; 1855, "Beatrice." These female heads, of a refined
+semi-ideal quality, with something of Venetian glow of tint, are the
+most satisfactory specimens of Eastlake's work to an artist's eye. He
+was an accomplished and judicious scholar in matters of art, and
+published, in 1840, a translation of Goethe's _Theory of Colours_; in
+1847 (his chief literary work) _Materials for a History of
+Oil-Painting_, especially valuable as regards the Flemish school; in
+1848, _Contributions to the Literature of the Fine Arts_ (a second
+series was edited by Lady Eastlake in 1870, and accompanied by a Memoir
+from her pen); in 1851 and 1855, translated editions of Kugler's
+_History of the Italian School of Painting_, and _Handbook of Painting_
+(new edition, by Lady Eastlake, 1874).
+
+  See W. Cosmo Monkhouse, _Pictures by Sir Charles Eastlake, with
+  biographical and critical Sketch_ (1875).     (W. M. R.)
+
+
+
+
+EAST LIVERPOOL, a city of Columbiana county, Ohio, U.S.A., on the Ohio
+river, about 106 m. S.E. of Cleveland. Pop. (1890) 10,956; (1900)
+16,485, of whom 2112 were foreign-born; (1910 census) 20,357. It is
+served by the Pennsylvania railway, by river steamboats, and by
+interurban electric lines. Next to Trenton, New Jersey, East Liverpool
+is the most important place in the United States for the manufacture of
+earthenware and pottery, 4859 out of its 5228 wage-earners, or 92.9%,
+being employed in this industry in 1905, when $5,373,852 (83.5% of the
+value of all its factory products) was the value of the earthenware and
+pottery. No other city in the United States is so exclusively devoted to
+the manufacture of pottery; in 1908 there were 32 potteries in the city
+and its immediate vicinity. The manufacture of white ware, begun in
+1872, is the most important branch of the industry--almost half of the
+"cream-coloured," white granite ware and semivitreous porcelain produced
+in the United States in 1905 (in value, $4,344,468 out of $9,195,703)
+being manufactured in East Liverpool. Though there are large clay
+deposits in the vicinity, very little of it can be used for crockery,
+and most of the clay used in the city's potteries is obtained from other
+states; some of it is imported from Europe. After 1872 a large number of
+skilled English pottery-workers settled in the city. The city's product
+of pottery, terra-cotta and fireclay increased from $2,137,063 to
+$4,105,200 from 1890 to 1900, and in the latter year almost equalled
+that of Trenton, N.J., the two cities together producing more than half
+(50.9%) of the total pottery product of the United States; in 1905 East
+Liverpool and Trenton together produced 42.1% of the total value of the
+country's pottery product. The municipality owns and operates its
+water-works. East Liverpool was settled in 1798, and was incorporated in
+1834.
+
+
+
+
+EAST LONDON, a town of the Cape province, South Africa, at the mouth of
+the Buffalo river, in 33° 1' S. 27° 55' E., 543 m. E.N.E. of Cape Town
+by sea and 666 m. S. of Johannesburg by rail. Pop. (1904) 25,220, of
+whom 14,674 were whites. The town is picturesquely situated on both
+sides of the river, which is spanned by a combined road and railway
+bridge. The railway terminus and business quarter are on the east side
+on the top of the cliffs, which rise 150 ft. above the river. In Oxford
+Street, the chief thoroughfare, is the town hall, a handsome building
+erected in 1898. Higher up a number of churches and a school are
+grouped round Vincent Square, a large open space. In consequence of the
+excellent sea bathing, and the beauty of the river banks above the town,
+East London is the chief seaside holiday resort of the Cape province.
+The town is the entrepot of a rich agricultural district, including the
+Transkei, Basutoland and the south of Orange Free State, and the port of
+the Cape nearest Johannesburg. It ranks third among the ports of the
+province. The roadstead is exposed and insecure, but the inner harbour,
+constructed at a cost of over £2,000,000, is protected from all winds. A
+shifting sand bar lies at the mouth of the river, but the building of
+training walls and dredging have increased the minimum depth of water to
+22 ft. From the east bank of the Buffalo a pier and from the west bank a
+breakwater project into the Indian Ocean, the entrance being 450 ft.
+wide, reduced between the training walls to 250 ft. There is extensive
+wharf accommodation on both sides of the river, and steamers of over
+8000 tons can moor alongside. There is a patent slip capable of taking
+vessels of 1000 tons dead weight. An aerial steel ropeway from the river
+bank to the town greatly facilitates the delivery of cargo. The imports
+are chiefly textiles, hardware and provisions, the exports mainly wool
+and mohair. The rateable value of the town in 1908 was £4,108,000, and
+the municipal rate 1-5/8 d.
+
+East London owes its foundation to the necessities of the Kaffir war of
+1846-1847. The British, requiring a port nearer the scene of war than
+those then existing, selected a site at the mouth of the Buffalo river,
+and in 1847 the first cargo of military stores was landed. A fort, named
+Glamorgan, was built, and the place permanently occupied. Around this
+military post grew up the town, known at first as Port Rex. Numbers of
+its inhabitants are descendants of German immigrants who settled in the
+district in 1857. The prosperity of the town dates from the era of
+railway and port development in the last decade of the 19th century. In
+1875 the value of the exports was £131,803 and that of the imports
+£552,033. In 1904 the value of the exports was £1,165,938 and that of
+the imports £4,688,415. In 1907 the exports, notwithstanding a period of
+severe trade depression, were valued at £1,475,355, but the imports had
+fallen to £3,354,633.
+
+
+
+
+EASTON, a city and the county-seat of Northampton county, Pennsylvania,
+U.S.A., at the confluence of the Lehigh river and Bushkill Creek with
+the Delaware, about 60 m. N. of Philadelphia. Pop. (1890) 14,481; (1900)
+25,238, of whom 2135 were foreign-born; (1910 census) 28,523. Easton is
+served by the Central of New Jersey, the Lehigh Valley, the Lehigh &
+Hudson River and the Delaware, Lackawanna & Western railways, and is
+connected by canals with the anthracite coal region to the north-west
+and with Bristol, Pa. A bridge across the Delaware river connects it
+with Phillipsburg, New Jersey, which is served by the Pennsylvania
+railway. The city is built on rolling ground, commanding pleasant views
+of hill and river scenery. Many fine residences overlook city and
+country from the hillsides, and a Carnegie library is prominent among
+the public buildings. Lafayette College, a Presbyterian institution
+opened in 1832, is finely situated on a bluff north of the Bushkill and
+Delaware. The college provides the following courses of instruction:
+graduate, classical, Latin scientific, general scientific, civil
+engineering, electrical engineering, mining engineering and chemical; in
+1908 it had 38 instructors and 442 students, 256 of whom were enrolled
+in the scientific and engineering courses. Overlooking the Bushkill is
+the Easton Cemetery, in which is the grave of George Taylor (1716-1781),
+a signer of the Declaration of Independence, with a monument of Italian
+marble to his memory. Among the city's manufactures are silk, hosiery
+and knit goods, flour, malt liquors, brick, tile, drills, lumber and
+planing mill products and organs; in 1905 the value of all the factory
+products was $5,654,594, of which $2,290,598, or 40.5%, was the value of
+the silk manufactures. Easton is the commercial centre of an important
+mining region, which produces, in particular, iron ore, soapstone,
+cement, slate and building stone. The municipality owns and operates an
+electric-lighting plant. Easton was a garden spot of the Indians, and
+here, because they would not negotiate elsewhere, several important
+treaties were made between 1756 and 1762 during the French and Indian
+War. The place was laid out in 1752, and was made the county-seat of the
+newly erected county. It was incorporated as a borough in 1789, received
+a new borough charter in 1823, and in 1887 was chartered as a city.
+South Easton was annexed in 1898.
+
+
+
+
+EAST ORANGE, a city of Essex county, New Jersey, U.S.A., in the
+north-eastern part of the state, adjoining the city of Newark, and about
+12 m. W. of New York city. Pop. (1890) 13,282; (1900) 21,506, of whom
+3950 were foreign-born and 1420 were negroes; (1910 census) 34,371. It
+is served by the Morris & Essex division of the Delaware, Lackawanna &
+Western railway and by the Orange branch of the Erie (the former having
+four stations--Ampere, Grove Street, East Orange and Brick Church), and
+is connected with Newark, Orange and West Orange by electric line. The
+city covers an area of about 4 sq. m., and has broad, well-paved
+streets, bordered with fine shade trees (under the jurisdiction of a
+"Shade Tree Commission"). It is primarily a residential suburb of New
+York and Newark, and has many beautiful homes; with Orange, West Orange
+and South Orange it forms virtually one community, popularly known as
+"the Oranges." The public school system is excellent, and the city has a
+Carnegie library (1903), with more than 22,000 volumes in 1907. Among
+the principal buildings are several attractive churches, the city hall,
+and the club-house of the Woman's Club of Orange. The principal
+manufactures of East Orange are electrical machinery, apparatus, and
+supplies (the factory of the Crocker-Wheeler Co. being here--in a part
+of the city known as "Ampere") and pharmaceutical materials. The total
+value of the city's factory products in 1905 was $2,326,552. East Orange
+has a fine water-works system, which it owns and operates; the water
+supply is obtained from artesian wells at White Oaks Ridge, in the
+township of Milburn (about 10 m. from the city hall); thence the water
+is pumped to a steel reinforced reservoir (capacity 5,000,000 gallons)
+on the mountain back of South Orange. In 1863 the township of East
+Orange was separated from the township of Orange, which, in turn, had
+been separated from the township of Newark in 1806. An act of the New
+Jersey legislature in 1895 created the office of township president,
+with power of appointment and veto. Four years later East Orange was
+chartered as a city.
+
+  See H. Whittemore, _The Founders and Builders of the Oranges_ (Newark,
+  1896).
+
+
+
+
+EASTPORT, a city and port of entry of Washington county, Maine, U.S.A.,
+co-extensive with Moose Island in Passamaquoddy Bay, about 190 m. E.N.E.
+of Portland. Pop. (1890) 4908; (1900) 5311 (1554 foreign-born); (1910)
+4961. It is served by the Washington County railway, and by steamboat
+lines to Boston, Portland and Calais. It is the most eastern city of the
+United States, and is separated from the mainland by a narrow channel,
+which is spanned by a bridge. The harbour is well protected from the
+winds, and the tide, which rises and falls here about 25 ft., prevents
+it from being obstructed with ice. The city is built on ground sloping
+gently to the water's edge, and commands delightful views of the bay, in
+which there are several islands. Its principal industry is the canning
+of sardines; there are also clam canneries. Shoes, mustard, decorated
+tin, and shooks are manufactured, and fish and lobsters are shipped from
+here in the season. The city is the port of entry for the customs
+district of Passamaquoddy; in 1908 its imports were valued at $994,961,
+and its exports at $1,155,791. Eastport was first settled about 1782 by
+fishermen; it became a port of entry in 1790, was incorporated as a town
+in 1798, and was chartered as a city in 1893. It was a notorious place
+for smuggling under the Embargo Acts of 1807 and 1808. On the 11th of
+July 1814, during the war of 1812, it was taken by the British. As the
+British government claimed the islands of Passamaquoddy Bay under the
+treaty of 1783, the British forces retained possession of Eastport after
+the close of the war and held it under martial law until July 1818, when
+it was surrendered in accordance with the decision rendered in November
+1817 by commissioners appointed under Article IV. of the treaty of Ghent
+(1814), this decision awarding Moose Island, Dudley Island and Frederick
+Island to the United States and the other islands, including the Island
+of Grand Manan in the Bay of Fundy, to Great Britain.
+
+
+
+
+EAST PROVIDENCE, a township of Providence county, Rhode Island, U.S.A.,
+on the E. side of Providence river, opposite Providence. Pop. (1890)
+8422; (1900) 12,138, of whom 2067 were foreign-born; (1910 census)
+15,808. Area, 12½ sq. m. It is served by the New York, New Haven &
+Hartford railway. It has a rolling surface and contains several
+villages, one of which, known as Rumford, has important manufactories of
+chemicals and electrical supplies. South of this village, along the
+river bank, are several attractive summer resorts, Hunt's Mills, Silver
+Spring, Riverside, Vanity Fair, Kettle Point and Bullock's Point being
+prominent among them. In 1905 the factory products of the township were
+valued at $5,035,288. The oyster trade is important. It was within the
+present limits of this township that Roger Williams established himself
+in the spring of 1636, until he learned that the place was within the
+jurisdiction of the Plymouth Colony. About 1644 it was settled by a
+company from Weymouth as a part of a town of Rehoboth. In 1812 Rehoboth
+was divided, and the west part was made the township of Seekonk.
+Finally, in 1861, it was decided that the west part of Seekonk belonged
+to Rhode Island, and in the following year that part was incorporated as
+the township of East Providence.
+
+
+
+
+EAST PRUSSIA (_Ost-Preussen_), the easternmost province of the kingdom
+of Prussia, bounded on the N. by the Baltic, on the E. and S.W. by
+Russia and Russian Poland, and on the W. by the Prussian province of
+West Prussia. It has an area of 14,284 sq. m., and had, in 1905, a
+population of 2,025,741. It shares in the general characteristics of the
+great north German plain, but, though low, its surface is by no means
+absolutely flat, as the southern half is traversed by a low ridge or
+plateau, which attains a height of 1025 ft. at a point near the western
+boundary of the province. This plateau, here named the Prussian
+Seenplatte, is thickly sprinkled with small lakes, among which is the
+Spirding See, 46 sq. m. in extent and the largest inland lake in the
+Prussian monarchy. The coast is lined with low dunes or sandhills, in
+front of which lie the large littoral lakes or lagoons named the
+Frisches Haff and the Kurisches Haff. The first of these receives the
+waters of the Nogat and the Pregel, and the other those of the Memel or
+Niemen. East Prussia is the coldest part of Germany, its mean annual
+temperature being about 44° F., while the mean January temperature of
+Tilsit is only 25°. The rainfall is 24 in. per annum. About half the
+province is under tillage; 18% is occupied by forests, and about 23% by
+meadows and pastures. The most fertile soil is found in the valleys of
+the Pregel and the Memel, but the southern slopes of the Baltic plateau
+and the district to the north of the Memel consist in great part of
+sterile moor, sand and bog. The chief crops are rye, oats and potatoes,
+while flax is cultivated in the district of Ermeland, between the
+Passarge and the upper Alle. East Prussia is the headquarters of the
+horse-breeding of the country, and contains the principal government
+stud of Trakehnen; numerous cattle are also fattened on the rich
+pastures of the river-valleys. The extensive woods in the south part of
+the province harbour a few wolves and lynxes, and the elk is still
+preserved in the forest of Ibenhorst, near the Kurisches Haff. The
+fisheries in the lakes and haffs are of some importance; but the only
+mineral product of note is amber, which is found in the peninsula of
+Samland in greater abundance than in any other part of the world.
+Manufactures are almost confined to the principal towns, though
+linen-weaving is practised as a domestic industry. Commerce is
+facilitated by canals connecting the Memel and Pregel and also the
+principal lakes, but is somewhat hampered by the heavy dues exacted at
+the Russian frontier. A brisk foreign trade is carried on through the
+seaports of Königsberg, the capital of the province, and Memel, the
+exports consisting mainly of timber and grain.
+
+The population of the province was in 1900 1,996,626, and included
+1,698,465 Protestants, 269,196 Roman Catholics and 13,877 Jews. The
+Roman Catholics are mainly confined to the district of Ermeland, in
+which the ordinary proportions of the confessions are completely
+reversed. The bulk of the inhabitants are of German blood, but there are
+above 400,000 Protestant Poles (Masurians or Masovians) in the south
+part of the province, and 175,000 Lithuanians in the north. As in other
+provinces where the Polish element is strong, East Prussia is somewhat
+below the general average of the kingdom in education. There is a
+university at Königsberg.
+
+  See Lohmeyer, _Geschichte von Ost- und West-Preussen_ (Gotha, 1884);
+  Brünneck, _Zur Geschichte des Kirchen-Patronats in Ost- und
+  West-Preussen_ (Berlin, 1902), and _Ost-Preussen, Land und Volk_
+  (Stuttgart, 1901-1902).
+
+
+
+
+EASTWICK, EDWARD BACKHOUSE (1814-1883), British Orientalist, was born in
+1814, a member of an Anglo-Indian family. Educated at Charterhouse and
+at Oxford, he joined the Bombay infantry in 1836, but, owing to his
+talent for languages, was soon given a political post. In 1843 he
+translated the Persian _Kessahi Sanján_, or _History of the Arrival of
+the Parsees in India_; and he wrote a _Life of Zoroaster_, a _Sindhi_
+vocabulary, and various papers in the transactions of the Bombay Asiatic
+Society. Compelled by ill-health to return to Europe, he went to
+Frankfort, where he learned German and translated Schiller's _Revolt of
+the Netherlands_ and Bopp's _Comparative Grammar_. In 1845 he was
+appointed professor of Hindustani at Haileybury College. Two years later
+he published a Hindustani grammar, and, in subsequent years, a new
+edition of the _Gulistán_, with a translation in prose and verse, also
+an edition with vocabulary of the Hindi translation by Lallú Lál of
+Chatur Chuj Misr's _Prem Sagár_, and translations of the _Bagh-o-Bahar_,
+and of the _Anvár-i Suhaili_ of Bídpáí. In 1851 he was elected a Fellow
+of the Royal Society. In 1857-1858 he edited _The Autobiography of
+Lútfullah_. He also edited for the Bible Society the Book of Genesis in
+the Dakhani language. From 1860 to 1863 he was in Persia as secretary to
+the British Legation, publishing on his return _The Journal of a
+Diplomate_. In 1866 he became private secretary to the secretary of
+state for India, Lord Cranborne (afterwards marquess of Salisbury), and
+in 1867 went, as in 1864, on a government mission to Venezuela. On his
+return he wrote, at the request of Charles Dickens, for _All the Year
+Round_, "Sketches of Life in a South American Republic." From 1868 to
+1874 he was M.P. for Penryn and Falmouth. In 1875 he received the degree
+of M.A. with the franchise from the university of Oxford, "as a slight
+recognition of distinguished services." At various times he wrote
+several of Murray's Indian hand-books. His last work was the
+_Kaisarnamah-i-Hind_ ("the lay of the empress"), in two volumes
+(1878-1882). He died at Ventnor, Isle of Wight, on the 16th of July
+1883.
+
+
+
+
+EATON, DORMAN BRIDGMAN (1823-1899), American lawyer, was born at
+Hardwick, Vermont, on the 27th of June 1823. He graduated at the
+university of Vermont in 1848 and at the Harvard Law School in 1850, and
+in the latter year was admitted to the bar in New York city. There he
+became associated in practice with William Kent, the son of the great
+chancellor, an edition of whose _Commentaries_ he assisted in editing.
+Eaton early became interested in municipal and civil service reform. He
+was conspicuous in the fight against Tweed and his followers, by one of
+whom he was assaulted; he required a long period of rest, and went to
+Europe, where he studied the workings of the civil service in various
+countries. From 1873 to 1875 he was a member of the first United States
+Civil Service Commission. In 1877, at the request of President Hayes, he
+made a careful study of the British civil service, and three years later
+published _Civil Service in Great Britain_. He drafted the Pendleton
+Civil Service Act of 1883, and later became a member of the new
+commission established by it. He resigned in 1885, but was almost
+immediately reappointed by President Cleveland, and served until 1886,
+editing the 3rd and 4th _Reports_ of the commission. He was an organizer
+(1878) of the first society for the furtherance of civil service reform
+in New York, of the National Civil Service Reform Association, and of
+the National Conference of the Unitarian Church (1865). He died in New
+York city on the 23rd of December 1899, leaving $100,000 each to Harvard
+and Columbia universities for the establishments of professorships in
+government. He was a legal writer and editor, and a frequent contributor
+to the leading reviews. In addition to the works mentioned he published
+_Should Judges be Elected?_ (1873), _The Independent Movement in New
+York_ (1880), _Term and Tenure of Office_ (1882), _The Spoils System and
+Civil Service Reform_ (1882), _Problems of Police Legislation_ (1895)
+and _The Government of Municipalities_ (1899).
+
+  See the privately printed memorial volume, _Dorman B. Eaton_,
+  1823-1899 (New York, 1900).
+
+
+
+
+EATON, MARGARET O'NEILL (1796-1879), better known as PEGGY O'NEILL, was
+the daughter of the keeper of a popular Washington tavern, and was noted
+for her beauty, wit and vivacity. About 1823, she married a purser in
+the United States navy, John B. Timberlake, who committed suicide while
+on service in the Mediterranean in 1828. In the following year she
+married John Henry Eaton (1790-1856), a Tennessee politician, at the
+time a member of the United States Senate. Senator Eaton was a close
+personal friend of President Jackson, who in 1829 appointed him
+secretary of war. This sudden elevation of Mrs Eaton into the cabinet
+social circle was resented by the wives of several of Jackson's
+secretaries, and charges were made against her of improper conduct with
+Eaton previous to her marriage to him. The refusal of the wives of the
+cabinet members to recognize the wife of his friend angered President
+Jackson, and he tried in vain to coerce them. Eventually, and partly for
+this reason, he almost completely reorganized his cabinet. The effect of
+the incident on the political fortunes of the vice-president, John C.
+Calhoun, whose wife was one of the recalcitrants, was perhaps most
+important. Partly on this account, Jackson's favour was transferred from
+Calhoun to Martin Van Buren, the secretary of state, who had taken
+Jackson's side in the quarrel and had shown marked attention to Mrs
+Eaton, and whose subsequent elevation to the vice-presidency and
+presidency through Jackson's favour is no doubt partly attributable to
+this incident. In 1836 Mrs Eaton accompanied her husband to Spain, where
+he was United States minister in 1836-1840. After the death of her
+husband she married a young Italian dancing-master, Antonio Buchignani,
+but soon obtained a divorce from him. She died in Washington on the 8th
+of November 1879.
+
+  See James Parton's _Life of Andrew Jackson_ (New York, 1860).
+
+
+
+
+EATON, THEOPHILUS (c. 1590-1658), English colonial governor in America,
+was born at Stony Stratford, Buckinghamshire, about 1590. He was
+educated in Coventry, became a successful merchant, travelled widely
+throughout Europe, and for several years was the financial agent of
+Charles I. in Denmark. He subsequently settled in London, where he
+joined the Puritan congregation of the Rev. John Davenport, whom he had
+known since boyhood. The pressure upon the Puritans increasing, Eaton,
+who had been one of the original patentees of the Massachusetts Bay
+colony in 1629, determined to use his influence and fortune to establish
+an independent colony of which his pastor should be the head. In 1637 he
+emigrated with Davenport to Massachusetts, and in the following year
+(March 1638) he and Davenport founded New Haven. In October 1639 a form
+of government was adopted, based on the Mosaic Law, and Eaton was
+elected governor, a post which he continued to hold by annual
+re-election, first over New Haven alone, and after 1643 over the New
+Haven Colony or Jurisdiction, until his death at New Haven on the 7th of
+January 1658. His administration was embarrassed by constantly recurring
+disputes with the neighbouring Dutch settlements, especially after
+Stamford (Conn.) and Southold (Long Island) had entered the New Haven
+Jurisdiction, but his prudence and diplomacy prevented an actual
+outbreak of hostilities. He was prominent in the affairs of the New
+England Confederation, of which he was one of the founders (1643). In
+1655 he and Davenport drew up the code of laws, popularly known as the
+"Connecticut Blue Laws," which were published in London in 1656 under
+the title _New Haven's Settling in New England and some Lawes for
+Government published for the Use of that Colony_.
+
+  A sketch of his life appears in Cotton Mather's _Magnalia_ (London,
+  1702); see also J.B. Moore's "Memoir of Theophilus Eaton" in the
+  _Collections_ of the New York Historical Society, second series, vol.
+  ii. (New York, 1849).
+
+
+
+
+EATON, WILLIAM (1764-1811), American soldier, was born in Woodstock,
+Connecticut, on the 23rd of February 1764. As a boy he served for a
+short time in the Continental army. He was a school teacher for several
+years, graduated at Dartmouth College in 1790, was clerk of the lower
+house of the Vermont legislature in 1791-1792, and in 1792 re-entered
+the army as a captain, later serving against the Indians in Ohio and
+Georgia. In 1797 he was appointed consul to Tunis, where he arrived in
+February 1799. In March 1799, with the consuls to Tripoli and Algiers,
+he negotiated alterations in the treaty of 1797 with Tunis. He rendered
+great service to Danish merchantmen by buying on credit several Danish
+prizes in Tunis and turning them over to their original owners for the
+redemption of his notes. In 1803 he quarrelled with the Bey, was ordered
+from the country, and returned to the United States to urge American
+intervention for the restoration of Ahmet Karamanli to the throne of
+Tripoli, arguing that this would impress the Barbary States with the
+power of the United States. In 1804 he returned to the Mediterranean as
+United States naval agent to the Barbary States with Barron's fleet. On
+the 23rd of February 1805 he agreed with Ahmet that the United States
+should undertake to re-establish him in Tripoli, that the expenses of
+the expedition should be repaid to the United States by Ahmet, and that
+Eaton should be general and commander-in-chief of the land forces in
+Ahmet's campaign; as the secretary of the navy had given the entire
+matter into the hands of Commodore Barron, and as Barron and Tobias Lear
+(1762-1816), the United States consul-general at Algiers and a
+diplomatic agent to conduct negotiations, had been instructed to
+consider the advisability of making arrangements with the existing
+government in Tripoli, Eaton far exceeded his authority. On the 8th of
+March he started for Derna across the Libyan desert from the Arab's
+Tower, 40 m. W. of Alexandria, with a force of about 500 men, including
+a few Americans, about 40 Greeks and some Arab cavalry. In the march of
+nearly 600 m. the camel-drivers and the Arab chiefs repeatedly mutinied,
+and Ahmet Pasha once put himself at the head of the Arabs and ordered
+them to attack Eaton. Ahmet more than once wished to give up the
+expedition. There were practically no provisions for the latter part of
+the march. On the 27th of April with the assistance of three bombarding
+cruisers Eaton captured Derna--an exploit commemorated by Whittier's
+poem _Derne_. On the 13th of May and on the 10th of June he successfully
+withstood the attacks of Tripolitan forces sent to dislodge him. On the
+12th of June he abandoned the town upon orders from Commodore Rodgers,
+for Lear had made peace (4th June) with Yussuf, the _de facto_ Pasha of
+Tripoli. Eaton returned to the United States, and received a grant of
+10,000 acres in Maine from the Massachusetts legislature. According to a
+deposition which he made in January 1807 he was approached by Aaron Burr
+(q.v.), who attempted to enlist him in his "conspiracy," and wished him
+to win over the marine corps and to sound Preble and Decatur. As he
+received from the government, soon after making this deposition, about
+$10,000 to liquidate claims for his expense in Tripoli, which he had
+long pressed in vain, his good faith has been doubted. At Burr's trial
+at Richmond in 1807 Eaton was one of the witnesses, but his testimony
+was unimportant. In May 1807 he was elected a member of the
+Massachusetts House of Representatives, and served for one term. He died
+on the 1st of June 1811 in Brimfield, Massachusetts.
+
+  See the anonymously published _Life of the Late Gen. William Eaton_
+  (Brookfield, Massachusetts, 1813) by Charles Prentiss; C.C. Felton,
+  "Life of William Eaton" in Sparks's _Library of American Biography_,
+  vol. ix. (Boston, 1838); and Gardner W. Allen's _Our Navy and the
+  Barbary Corsairs_ (Boston, 1905).
+
+
+
+
+EATON, WYATT (1849-1896), American portrait and figure painter, was born
+at Philipsburg, Canada, on the 6th of May 1849. He was a pupil of the
+schools of the National Academy of Design, New York, and in 1872 went to
+Paris, where he studied in the École des Beaux-Arts under J.L. Gérôme.
+He made the acquaintance of J.F. Millet at Barbizon, and was also
+influenced by his friend Jules Bastien-Lepage. After his return to the
+United States in 1876 he became a teacher in Cooper Institute and opened
+a studio in New York city. He was one of the organizers (and the first
+secretary) of the Society of American Artists. Among his portraits are
+those of William Cullen Bryant and Timothy Cole, the wood engraver ("The
+Man with the Violin"). Eaton died at Newport, Rhode Island, on the 7th
+of June 1896.
+
+
+
+
+EAU CLAIRE, a city and the county-seat of Eau Claire county, Wisconsin,
+U.S.A., on the Chippewa river, at the mouth of the Eau Claire, about 87
+m. E. of St Paul. Pop. (1890) 17,415; (1900) 17,517, of whom 4996 were
+foreign-born; (1910 census) 18,310. It is served by the Chicago &
+North-Western, the Chicago, Milwaukee & St Paul, and the Wisconsin
+Central railways, and is connected by an electric line with Chippewa
+Falls (12 m. distant). The city has a Carnegie library with 17,200
+volumes in 1908, a Federal building, county court house, normal school
+and insane asylum. It has abundant water-power, and is an important
+lumber manufacturing centre; among its other manufactures are flour,
+wooden-ware, agricultural machinery, saw-mill machinery, logging
+locomotives, wood pulp, paper, linen, mattresses, shoes and trunks. The
+total value of factory products in 1905 was $3,601,558. The city is the
+principal wholesale and jobbing market for the prosperous Chippewa
+Valley. Eau Claire was first settled about 1847, and was chartered as a
+city in 1872; its growth dates from the development of the north-western
+lumber trade in the decade 1870-1880. In 1881 a serious strike
+necessitated the calling out of state militia for its suppression and
+the protection of property.
+
+
+
+
+EAU DE COLOGNE (Ger. _Kölnisches Wasser_, "Cologne water"), a perfume,
+so named from the city of Cologne, where its manufacture was first
+established by an Italian, Johann (or Giovanni) Maria Farina
+(1685-1766), who settled at Cologne in 1709. The perfume gained a high
+reputation by 1766, and Farina associated himself with his nephew, to
+whose grandson the secret was ultimately imparted; the original perfume
+is still manufactured by members of this family under the name of the
+founder. The manufacture is, however, carried on at Cologne, and also in
+Italy, by other firms bearing the name Farina, and the scent has become
+part of the regular output of perfumers. The discovery has also been
+ascribed to a Paul de Feminis, who is supposed to have brought his
+recipe from Milan to Cologne, of which he became a citizen in 1690, and
+sold the perfume under the name _Eau admirable_, leaving the secret at
+his death to his nephew Johann Maria Farina. Certain of the Farinas
+claim to use his process. It was originally prepared by making an
+alcoholic infusion of certain flowers, pot-herbs, drugs and spices,
+distilling and then adding definite quantities of several vegetable
+essences. The purity and thorough blending of the ingredients are of the
+greatest importance. The original perfume is simulated and even excelled
+by artificial preparations. The oils of lemon, bergamot and orange are
+employed, together with the oils of neroli and rosemary in the better
+class. The common practice consists in dissolving the oils, in certain
+definite proportions based on experience, in pure alcohol and
+distilling, the distillate being diluted by rose-water.
+
+
+
+
+EAUX-BONNES, a watering-place of south-western France, in the department
+of Basses-Pyrénées, 3½ m. S.E. of the small town of Laruns, the latter
+being 24 m. S. of Pau by rail. Pop. (1906) 610. Eaux-Bonnes is situated
+at a height of 2460 ft. at the entrance of a fine gorge, overlooking the
+confluence of two torrents, the Valentin and the Sourde. The village is
+well known for its sulphurous and saline mineral waters (first mentioned
+in the middle of the 14th century), which are beneficial in affections
+of the throat and lungs. They vary between 50° and 90° F. in
+temperature, and are used for drinking and bathing. There are two
+thermal establishments, a casino and fine promenades.
+
+The watering-place of LES EAUX-CHAUDES is 5 m. by road south-west of
+Eaux-Bonnes, in a wild gorge on the Gave d'Ossau. The springs are
+sulphurous, varying in temperature from 52° to 97° F., and are used in
+cases of rheumatism, certain maladies of women, &c. The thermal
+establishment is a handsome marble building.
+
+There is fine mountain scenery in the neighbourhood of both places, the
+Pic de Ger near Eaux-Bonnes, commanding an extensive view. The valley of
+Ossau, one of the most beautiful in the Pyrenees, before the Revolution
+formed a community which, though dependent on Béarn, had its own legal
+organization, manners and costumes, the last of which are still to be
+seen on holidays.
+
+
+
+
+EAVES (not a plural form as is sometimes supposed, but singular; O. Eng.
+_efes_, in Mid. High Ger. _obse_, Gothic _ubizwa_, a porch; connected
+with "over"), in architecture, the projecting edge of a sloping roof,
+which overhangs the face of the wall so as to throw off the water.
+
+
+
+
+EAVESDRIP, or EAVESDROP, that width of ground around a house or building
+which receives the rain water dropping from the eaves. By an ancient
+Saxon law, a landowner was forbidden to erect any building at less than
+2 ft. from the boundary of his land, and was thus prevented from
+injuring his neighbour's house or property by the dripping of water from
+his eaves. The law of Eavesdrip has had its equivalent in the Roman
+_stillicidium_, which prohibited building up to the very edge of an
+estate.
+
+From the Saxon custom arose the term "eavesdropper," i.e. any one who
+stands within "the eavesdrop" of a house, hence one who pries into
+others' business or listens to secrets. At common law an eavesdropper
+was regarded as a common nuisance, and was presentable at the court
+leet, and indictable at the sheriff's tourn and punishable by fine and
+finding sureties for good behaviour. Though the offence of eavesdropping
+still exists at common law, there is no modern instance of a prosecution
+or indictment.
+
+
+
+
+EBBW VALE, an urban district in the western parliamentary division of
+Monmouthshire, England, 21 m. N.W. of Newport on the Great Western,
+London & North-Western and Rhymney railways. Pop. (1891) 17,312; (1901)
+20,994. It lies near the head of the valley of the river Ebbw, at an
+elevation of nearly 1000 ft., in a wild and mountainous mining district,
+which contains large collieries and important iron and steel works.
+
+
+
+
+EBEL, HERMANN WILHELM (1820-1875), German philologist, was born at
+Berlin on the 10th of May 1820. He displayed in his early years a
+remarkable capacity for the study of languages, and at the same time a
+passionate fondness for music and poetry. At the age of sixteen he
+became a student at the university of Berlin, applying himself
+especially to philology, and attending the lectures of Böckh. Music
+continued to be the favourite occupation of his leisure hours, and he
+pursued the study of it under the direction of Marx. In the spring of
+1838 he passed to the university of Halle, and there began to apply
+himself to comparative philology under Pott. Returning in the following
+year to his native city, he continued this study as a disciple of Bopp.
+He took his degree in 1842, and, after spending his year of probation at
+the French Gymnasium of Berlin, he resumed with great earnestness his
+language studies. About 1847 he began to study Old Persian. In 1852 he
+accepted a professorship at the Beheim-Schwarzbach Institution at
+Filehne, which post he held for six years. It was during this period
+that his studies in the Old Slavic and Celtic languages began. In 1858
+he removed to Schneidemühl, and there he discharged the duties of first
+professor for ten years. He was afterwards called to the chair of
+comparative philology at the university of Berlin. He died at Misdroy on
+the 19th of August 1875. The most important work of Dr Ebel in the field
+of Celtic philology is his revised edition of the _Grammatica Celtica_
+of Professor Zeuss, completed in 1871. This had been preceded by his
+treatises--_De verbi Britannici futuro ac conjunctivo_ (1866), and _De
+Zeussii curis positis in Grammatica Celtica_ (1869). He made many
+learned contributions to Kühn's _Zeitschrift für vergleichende
+Sprachforschung_, and to A. Schleicher's _Beiträge zur vergleichenden
+Sprachforschung_; and a selection of these contributions was translated
+into English by Sullivan, and published under the title of _Celtic
+Studies_ (1863). Ebel contributed the Old Irish section to Schleicher's
+_Indogermanische Chrestomathie_ (1869). Among his other works must be
+named _Die Lehnwörter der deutschen Sprache_ (1856).
+
+
+
+
+EBEL, JOHANN GOTTFRIED (1764-1830), the author of the first real
+guide-book to Switzerland, was born at Züllichau (Prussia). He became a
+medical man, visited Switzerland for the first time in 1790, and became
+so enamoured of it that he spent three years exploring the country and
+collecting all kinds of information relating to it. The result was the
+publication (Zürich, 1793) of his _Anleitung auf die nützlichste und
+genussvollste Art in der Schweitz zu reisen_ (2 vols.), in which he gave
+a complete account of the country, the General Information sections
+being followed by an alphabetically arranged list of places, with
+descriptions. It at once superseded all other works of the kind, and was
+the best Swiss guide-book till the appearance of "Murray" (1838). It was
+particularly strong on the geological and historical sides. The second
+(1804-1805) and third (1809-1810) editions filled four volumes, but the
+following (the 8th appeared in 1843) were in a single volume. The work
+was translated into French in 1795 (many later editions) and into
+English (by 1818). Ebel also published a work (2 vols., Leipzig,
+1798-1802) entitled _Schilderungen der Gebirgsvölker der Schweiz_, which
+deals mainly with the pastoral cantons of Glarus and Appenzell. In 1801
+he was naturalized a Swiss citizen, and settled down in Zürich. In 1808
+he issued his chief geological work, _Über den Bau der Erde im
+Alpengebirge_ (Zürich, 2 vols.). He took an active share in promoting
+all that could make his adopted country better known, e.g. Heinrich
+Keller's map (1813), the building of a hotel on the Rigi (1816), and the
+preparation of a panorama from that point (1823). From 1810 onwards he
+lived at Zürich, with the family of his friend, Conrad Escher von der
+Linth (1767-1823), the celebrated engineer.     (W. A. B. C.)
+
+
+
+
+EBER, PAUL (1511-1569), German theologian, was born at Kitzingen in
+Franconia, and was educated at Nuremberg and Wittenberg, where he became
+the close friend of Philip Melanchthon. In 1541 he was appointed
+professor of Latin grammar at Wittenberg, and in 1557 professor of the
+Old Testament. His range of learning was wide, and he published a
+handbook of Jewish history, a historical calendar intended to supersede
+the Roman Saints' Calendar, and a revision of the Latin Old Testament.
+In the theological conflict of the time he played a large part, doing
+what he could to mediate between the extremists. From 1559 to the close
+of his life he was superintendent-general of the electorate of Saxony.
+He attained some fame as a hymn-writer, his best-known composition being
+"Wenn wir in höchsten Nöthen sein." He died at Wittenberg on the 10th of
+December 1569.
+
+
+
+
+EBERBACH, a town of Germany, in the grand-duchy of Baden, romantically
+situated on the Neckar, at the foot of the Katzenbuckel, 19 m. E. of
+Heidelberg by the railway to Würzburg. Pop. (1900) 5857. It contains an
+Evangelical and a Roman Catholic church, a commercial and a technical
+school, and, in addition to manufacturing cigars, leather and cutlery,
+carries on by water an active trade in timber and wine. Eberbach was
+founded in 1227 by the German king Henry VII., who acquired the castle
+(the ruins of which overhang the town) from the bishop of Worms. It
+became an imperial town and passed later to the Palatinate.
+
+  See Wirth, _Geschichte der Stadt Eberbach_ (Stuttgart, 1864).
+
+
+
+
+EBERBACH, a famous Cistercian monastery of Germany, in the Prussian
+province of Hesse-Nassau, situated near Hattenheim in the Rheingau, 10
+m. N.W. from Wiesbaden. Founded in 1116 by Archbishop Adalbert of Mainz,
+as a house of Augustinian canons regular, it was bestowed by him in 1131
+upon the Benedictines, but was shortly afterwards repurchased and
+conferred upon the Cistercian order. The Romanesque church (consecrated
+in 1186) contains numerous interesting monuments and tombs, notable
+among them being those of the archbishop of Mainz, Gerlach (d. 1371)
+and Adolph II. of Nassau (d. 1475). It was despoiled during the Thirty
+Years' War, was secularized in 1803, and now serves as a house of
+correction. Its cellars contain some of the finest vintages of the Rhine
+wines of the locality.
+
+  See Bär, _Diplomatische Geschichte der Abtei Eberbach_ (Wiesb.,
+  1851-1858 and 1886, 3 vols.), and Schäfer, _Die Abtei Eberbach im
+  Mittelalter_ (Berlin, 1901).
+
+
+
+
+EBERHARD, surnamed IM BART (_Barbatus_), count and afterwards duke of
+Württemberg (1445-1496), was the second son of Louis I., count of
+Württemberg-Urach (d. 1450), and succeeded his elder brother Louis II.
+in 1457. His uncle Ulrich V., count of Württemberg-Stuttgart (d. 1480),
+acted as his guardian, but in 1459, assisted by Frederick I., elector
+palatine, he threw off this restraint, and undertook the government of
+the district of Urach as Count Eberhard V. He neglected his duties as a
+ruler and lived a reckless life until 1468, when he made a pilgrimage to
+Jerusalem. He visited Italy, became acquainted with some famous
+scholars, and in 1474 married Barbara di Gonzaga, daughter of Lodovico
+III., marquis of Mantua, a lady distinguished for her intellectual
+qualities. In 1482 he brought about the treaty of Münsingen with his
+cousin Eberhard VI., count of Württemberg-Stuttgart. By this treaty the
+districts of Urach and Stuttgart into which Württemberg had been divided
+in 1437 were again united, and for the future the county was declared
+indivisible, and the right of primogeniture established. The treaty led
+to some disturbances, but in 1492 the sanction of the nobles was secured
+for its provisions. In return for this Eberhard agreed to some
+limitations on the power of the count, and so in a sense founded the
+constitution of Württemberg. At the diet of Worms in 1495 the emperor
+Maximilian I. guaranteed the treaty, confirmed the possessions and
+prerogatives of the house of Württemberg, and raised Eberhard to the
+rank of duke. Eberhard, although a lover of peace, was one of the
+founders of the Swabian League in 1488, and assisted to release
+Maximilian, then king of the Romans, from his imprisonment at Bruges in
+the same year. He gave charters to the towns of Stuttgart and Tübingen,
+and introduced order into the convents of his land, some of which he
+secularized. He took a keen interest in the new learning, founded the
+university of Tübingen in 1476, befriended John Reuchlin, whom he made
+his private secretary, welcomed scholars to his court, and is said to
+have learned Latin in later life. In 1482 he again visited Italy and
+received the Golden Rose from Pope Sixtus IV. He won the esteem of the
+emperors Frederick III. and Maximilian I. on account of his wisdom and
+fidelity, and his people held him in high regard. His later years were
+mainly spent at Stuttgart, but he died at Tübingen on the 25th of
+February 1496, and in 1537 his ashes were placed in the choir of the
+Stiftskirche there. Eberhard left no children, and the succession passed
+to his cousin Eberhard, who became Duke Eberhard II.
+
+  See Rösslin, _Leben Eberhards im Barte_ (Tübingen, 1793); Bossert,
+  _Eberhard im Bart_ (Stuttgart, 1884).
+
+
+
+
+EBERHARD, CHRISTIAN AUGUST GOTTLOB (1769-1845), German miscellaneous
+writer, was born at Belzig, near Wittenberg, on the 12th of January
+1769. He studied theology at Leipzig; but, a story he contributed to a
+periodical having proved successful, he devoted himself to literature.
+With the exception of _Hannchen und die Küchlein_ (1822), a narrative
+poem in ten parts, and an epic on the Creation, _Der erste Mensch und
+die Erde_ (1828), Eberhard's work was ephemeral in character and is now
+forgotten. He died at Dresden on the 13th of May 1845.
+
+  His collected works (_Gesammelte Schriften_) appeared in 20 volumes in
+  1830-1831.
+
+
+
+
+EBERHARD, JOHANN AUGUSTUS (1739-1809), German theologian and
+philosopher, was born at Halberstadt in Lower Saxony, where his father
+was singing-master at the church of St Martin's, and teacher of the
+school of the same name. He studied theology at the university of Halle,
+and became tutor to the eldest son of the baron von der Horst, to whose
+family he attached himself for a number of years. In 1763 he was
+appointed con-rector of the school of St Martin's, and second preacher
+in the hospital church of the Holy Ghost; but he soon afterwards
+resigned these offices and followed his patron to Berlin. There he met
+Nicolai and Moses Mendelssohn, with whom he formed a close friendship.
+In 1768 he became preacher or chaplain to the workhouse at Berlin and
+the neighbouring fishing village of Stralow. Here he wrote his _Neue
+Apologie des Socrates_ (1772), a work occasioned by an attack on the
+fifteenth chapter of Marmontel's _Belisarius_ made by Peter Hofstede, a
+clergyman of Rotterdam, who maintained the patristic view that the
+virtues of the noblest pagans were only _splendida peccata_. Eberhard
+stated the arguments for the broader view with dignity, acuteness and
+learning, but the liberality of the reasoning gave great offence to the
+strictly orthodox divines, and is believed to have obstructed his
+preferment in the church.
+
+In 1774 he was appointed to the living of Charlottenburg. A second
+volume of his _Apologie_ appeared in 1778. In this he not only
+endeavoured to obviate some objections which were taken to the former
+part, but continued his inquiries into the doctrines of the Christian
+religion, religious toleration and the proper rules for interpreting the
+Scriptures. In 1778 he accepted the professorship of philosophy at
+Halle. As an academical teacher, however, he was unsuccessful. His
+powers as an original thinker were not equal to his learning and his
+literary gifts, as was shown in his opposition to the philosophy of
+Kant. In 1786 he was admitted a member of the Berlin Academy of
+Sciences; in 1805 the king of Prussia conferred upon him the honorary
+title of a privy-councillor. In 1808 he obtained the degree of doctor in
+divinity, which was given him as a reward for his theological writings.
+He died on the 6th of January 1809. He was master of the learned
+languages, spoke and wrote French with facility and correctness, and
+understood English, Italian and Dutch. He possessed a just and
+discriminating taste for the fine arts, and was a great lover of music.
+
+  Works:--_Neue Apologie des Socrates_, &c. (2 vols., 1772-1778);
+  _Allgemeine Theorie des Denkens und Empfindens_, &c. (Berlin, 1776),
+  an essay which gained the prize assigned by the Royal Society of
+  Berlin for that year; _Von dem Begriff der Philosophie und ihren
+  Theilen_ (Berlin, 1778)--a short essay, in which he announced the plan
+  of his lectures on being appointed to the professorship at Halle;
+  _Lobschrift auf Herrn Johann Thunmann Prof. der Weltweisheit und
+  Beredsamkeit auf der Universität zu Halle_ (Halle, 1779); _Amyntor,
+  eine Geschichte in Briefen_ (Berlin, 1782)--written with the view of
+  counteracting the influence of those sceptical and Epicurean
+  principles in religion and morals then so prevalent in France, and
+  rapidly spreading amongst the higher ranks in Germany; _Über die
+  Zeichen der Aufklärung einer Nation_, &c. (Halle, 1783); _Theorie der
+  schönen Künste und Wissenschaften_, &c. (Halle, 1783, 3rd ed. 1790);
+  _Vermischte Schriften_ (Halle, 1784); _Neue vermischte Schriften_ (ib.
+  1786); _Allgemeine Geschichte der Philosophie_, &c. (Halle, 1788), 2nd
+  ed. with a continuation and chronological tables (1796); _Versuch
+  einer allgemeinen-deutschen Synonymik_ (Halle and Leipzig, 1795-1802,
+  6 vols., 4th ed. 1852-1853), long reckoned the best work on the
+  synonyms of the German language (an abridgment of it was published by
+  the author in one large volume, Halle, 1802); _Handbuch der Aesthetik_
+  (Halle, 1803-1805, 2nd ed. 1807-1820). He also edited the
+  _Philosophisches Magazin_ (1788-1792) and the _Philosophisches Archiv_
+  (1792-1795).
+
+  See F. Nicolai, _Gedächtnisschrift auf J.A. Eberhard_ (Berlin and
+  Stettin, 1810); also K.H. Jördens, _Lexicon deutscher Dichter und
+  Prosaisten_.
+
+
+
+
+EBERLIN, JOHANN ERNST (1702-1762), German musician and composer, was
+born in Bavaria, and became afterwards organist in the cathedral at
+Salzburg, where he died. Most of his compositions were for the church
+(oratorios, &c.), but he also wrote some important fugues, sonatas and
+preludes; and his pieces were at one time highly valued by Mozart.
+
+
+
+
+EBERS, GEORG MORITZ (1837-1898), German Egyptologist and novelist, was
+born in Berlin on the 1st of March 1837. At Göttingen he studied
+jurisprudence, and at Berlin oriental languages and archaeology. Having
+made a special study of Egyptology, he became in 1865 _docent_ in
+Egyptian language and antiquities at Jena, and in 1870 he was appointed
+professor in these subjects at Leipzig. He had made two scientific
+journeys to Egypt, and his first work of importance, _Ägypten und die
+Bücher Moses_, appeared in 1867-1868. In 1874 he edited the celebrated
+medical papyrus ("Papyrus Ebers") which he had discovered in Thebes
+(translation by H. Joachim, 1890). Ebers early conceived the idea of
+popularizing Egyptian lore by means of historical romances. _Eine
+ägyptische Königstochter_ was published in 1864, and obtained great
+success. His subsequent works of the same kind--_Uarda_ (1877), _Homo
+sum_ (1878), _Die Schwestern_ (1880), _Der Kaiser_ (1881), of which the
+scene is laid in Egypt at the time of Hadrian, _Serapis_ (1885), _Die
+Nilbraut_ (1887), and _Kleopatra_ (1894), were also well received, and
+did much to make the public familiar with the discoveries of
+Egyptologists. Ebers also turned his attention to other fields of
+historical fiction--especially the 16th century (_Die Frau
+Bürgermeisterin_, 1882; _Die Gred_, 1887)--without, however, attaining
+the success of his Egyptian novels. Apart from their antiquarian and
+historical interest, Ebers's books have not a very high literary value.
+His other writings include a descriptive work on Egypt (_Ägypten in Wort
+und Bild_, 2nd ed., 1880), a guide to Egypt (1886) and a life (1885) of
+his old teacher, the Egyptologist Karl Richard Lepsius. The state of his
+health led him in 1889 to retire from his chair at Leipzig on a pension.
+He died at Tutzing in Bavaria, on the 7th of August 1898.
+
+  Ebers's _Gesammelte Werke_ appeared in 25 vols. at Stuttgart
+  (1893-1895). Many of his books have been translated into English. For
+  his life see his _Die Geschichte meines Lebens_ (Stuttgart, 1893);
+  also R. Gosche, _G. Ebers, der Forscher und Dichter_ (2nd ed.,
+  Leipzig, 1887).
+
+
+
+
+EBERSWALDE, a town of Germany, in the kingdom of Prussia, 28 m. N.E. of
+Berlin by rail; on the Finow canal. Pop. (1905) 23,876. The town has a
+Roman Catholic and two Evangelical churches, a school of forestry, a
+gymnasium, a higher-grade girls' school and two schools of domestic
+economy. It possesses a mineral spring, which attracts numerous summer
+visitors, and has various industries, which include iron-founding and
+the making of horse-shoe nails, roofing material and bricks. A
+considerable trade is carried on in grain, wood and coals. In the
+immediate neighbourhood are one of the chief brass-foundries in Germany
+and an extensive government paper-mill, in which the paper for the notes
+of the imperial bank is manufactured.
+
+Eberswalde received its municipal charter in 1257. It was taken and
+sacked during the Thirty Years' War. In 1747 Frederick the Great brought
+a colony of Thuringian cutlers to the town, but this branch of industry
+has entirely died out. About 4 m. to the north lies the old Cistercian
+monastery of Chorin, the fine Gothic church of which contains the tombs
+of several margraves of Brandenburg.
+
+
+
+
+EBERT, FRIEDRICH ADOLF (1791-1834), German bibliographer, was born at
+Taucha, near Leipzig, on the 9th of July 1791, the son of a Lutheran
+pastor. At the age of fifteen he was appointed to a subordinate post in
+the municipal library of Leipzig. He studied theology for a short time
+at Leipzig, and afterwards philology at Wittenberg, where he graduated
+doctor in philosophy in 1812. While still a student he had already
+published, in 1811, a work on public libraries, and in 1812 another work
+entitled _Hierarchiae in religionem ac literas commoda_. In 1813 he was
+attached to the Leipzig University library, and in 1814 was appointed
+secretary to the Royal library of Dresden. The same year he published
+_F. Taubmanns Leben und Verdienste_, and in 1819 _Torquato Tasso_, a
+translation from Pierre Louis Ginguené with annotations. The rich
+resources open to him in the Dresden library enabled him to undertake
+the work on which his reputation chiefly rests, the _Allgemeines
+bibliographisches Lexikon_, the first volume of which appeared in 1821
+and the second in 1830. This was the first work of the kind produced in
+Germany, and the most scientific published anywhere. From 1823 to 1825
+Ebert was librarian to the duke of Brunswick at Wolfenbüttel, but
+returning to Dresden was made, in 1827, chief librarian of the Dresden
+Royal library. Among his other works are--_Die Bildung des
+Bibliothekars_ (1820), _Geschichte und Beschreibung der königlichen
+öffentlichen Bibliothek in Dresden_ (1822), _Zur Handschriftenkunde_
+(1825-1827), and _Culturperioden des obersächsischen Mittelalters_
+(1825). Ebert was a contributor to various journals and took part in the
+editing of Ersch and Gruber's great encyclopaedia. He died at Dresden on
+the 13th of November 1834, in consequence of a fall from the ladder in
+his library.
+
+  See the article in _Ersch und Grubers Encyclopädie_, and that in the
+  _Allg. deutsche Biog._ by his successor in the post of chief librarian
+  in Dresden, Schnorr von Carolsfeld.
+
+
+
+
+
+EBINGEN, a town of Germany, in the kingdom of Württemberg, on the
+Schmiecha, a left-hand tributary of the Danube, 22 m. S. of Tübingen and
+37 m. W. of Ulm by rail. It manufactures velvet and cotton-velvet
+("Manchester") goods, stockings, stays, hats, needles, tools, &c. There
+are also tanneries. Pop. 9000.
+
+
+
+
+EBIONITES (Heb. [Hebrew: ebyonim], "poor men"), a name given to the
+ultra-Jewish party in the early Christian church. It is first met with
+in Irenaeus (_Adv. Haer._ i. 26. 2), who sheds no light on the origin of
+the Ebionites, but says that while they admit the world to have been
+made by the true God (in contrast to the Demiurge of the Gnostics), they
+held Cerinthian views on the person of Christ, used only the Gospel of
+Matthew (probably the Gospel according to the Hebrews--so Eusebius), and
+rejected Paul as an apostate from the Mosaic Law, to the customs and
+ordinances of which, including circumcision, they steadily adhered. A
+similar account is given by Hippolytus (_Haer._ vii. 35), who invents a
+founder named Ebion. Origen (_Contra Celsum_, v. 61; _In Matt._ tom.
+xvi. 12) divides the Ebionites into two classes according to their
+acceptance or rejection of the virgin birth of Jesus, but says that all
+alike reject the Pauline epistles. This is confirmed by Eusebius, who
+adds that even those who admitted the virgin birth did not accept the
+pre-existence of Jesus as Logos and Sophia. They kept both the Jewish
+Sabbath and the Christian Lord's day, and held extreme millenarian ideas
+in which Jerusalem figured as the centre of the coming Messianic
+kingdom. Epiphanius with his customary confusion makes two separate
+sects, Ebionites and Nazarenes. Both names, however, refer to the same
+people[1] (the Jewish Christians of Syria), the latter going back to the
+designation of apostolic times (Acts xxiv. 5), and the former being the
+term usually applied to them in the ecclesiastical literature of the 2nd
+and 3rd centuries.
+
+The origin of the Nazarenes or Ebionites as a distinct sect is very
+obscure, but may be dated with much likelihood from the edict of Hadrian
+which in 135 finally scattered the old church of Jerusalem. While
+Christians of the type of Aristo of Pella and Hegesippus, on the
+snapping of the old ties, were gradually assimilated to the great church
+outside, the more conservative section became more and more isolated and
+exclusive. "It may have been then that they called themselves the Poor
+Men, probably as claiming to be the true representatives of those who
+had been blessed in the Sermon on the Mount, but possibly adding to the
+name other associations." Out of touch with the main stream of the
+church they developed a new kind of pharisaism. Doctrinally they stood
+not so much for a theology as for a refusal of theology, and, rejecting
+the practical liberalism of Paul, became the natural heirs of those
+early Judaizers who had caused the apostle so much annoyance and
+trouble.
+
+Though there is insufficient justification for dividing the Ebionites
+into two separate and distinct communities, labelled respectively
+Ebionites and Nazarenes, we have good evidence, not only that there were
+grades of Christological thought among them, but that a considerable
+section, at the end of the 2nd century and the beginning of the 3rd,
+exchanged their simple Judaistic creed for a strange blend of Essenism
+and Christianity. These are known as the Helxaites or Elchasaites, for
+they accepted as a revelation the "book of Elchasai," and one Alcibiades
+of Apamea undertook a mission to Rome about 220 to propagate its
+teaching. It was claimed that Christ, as an angel 96 miles high,
+accompanied by the Holy Spirit, as a female angel of the same stature,
+had given the revelation to Elchasai in the 3rd year of Trajan (A.D.
+100), but the book was probably quite new in Alcibiades' time. It taught
+that Christ was an angel born of human parents, and had appeared both
+before (e.g. in Adam and Moses) and after this birth in Judea. His
+coming did not annul the Law, for he was merely a prophet and teacher;
+Paul was wrong and circumcision still necessary. Baptism must be
+repeated as a means of purification from sin, and proof against disease;
+the sinner immerses himself "in the name of the mighty and most high
+God," invoking the "seven witnesses" (sky, water, the holy spirits, the
+angels of prayer, oil, salt and earth), and pledging himself to
+amendment. Abstinence from flesh was also enjoined, and a good deal of
+astrological fancy was interwoven with the doctrinal and practical
+teaching. It is highly probable, too, that from these Essene Ebionites
+there issued the fantastical and widely read "Clementine" literature
+(_Homilies_ and _Recognitions_) of the 3rd century. Ebionite views
+lingered especially in the country east of the Jordan until they were
+absorbed by Islam in the 7th century.
+
+  In addition to the literature cited see R.C. Ottley, _The Doctrine of
+  the Incarnation_, part iii. § ii.; W. Moeller, _Hist. of the Christian
+  Church_, i. 99; art. in Herzog-Hauck, _Realencyklopädie_, s.v.
+  "Ebioniten"; also CLEMENTINE LITERATURE.
+
+
+FOOTNOTE:
+
+  [1] So A. Harnack, _Hist. of Dogma_, i. 301, and F.J.A. Hort,
+    _Judaistic Christianity_, p. 199. Th. Zahn and J.B. Lightfoot ("St.
+    Paul and the Three," in _Commentary on Galatians_) maintain the
+    distinction.
+
+
+
+
+EBNER-ESCHENBACH, MARIE, FREIFRAU VON (1830- ), Austrian novelist, was
+born at Zdislavic in Moravia, on the 13th of September 1830, the daughter
+of a Count Dubsky. She lost her mother in early infancy, but received a
+careful intellectual training from two stepmothers. In 1848 she married
+the Austrian captain, and subsequent field-marshal, Moritz von
+Ebner-Eschenbach, and resided first at Vienna, then at Klosterbruck, where
+her husband had a military charge, and after 1860 again at Vienna. The
+marriage was childless, and the talented wife sought consolation in
+literary work. In her endeavours she received assistance and encouragement
+from Franz Grillparzer and Freiherr von Münch-Bellinghausen. Her first
+essay was with the drama _Maria Stuart in Schottland_, which Philipp
+Eduard Devrient produced at the Karlsruhe theatre in 1860. After some
+other unsuccessful attempts in the field of drama, she found her true
+sphere in narrative. Commencing with _Die Prinzessin von Banalien_ (1872),
+she graphically depicts in _Bozena_ (Stuttgart, 1876, 4th ed. 1899) and
+_Das Gemeindekind_ (Berlin, 1887, 4th ed. 1900) the surroundings of her
+Moravian home, and in _Lotti, die Uhrmacherin_ (Berlin, 1883, 4th ed.
+1900), _Zwei Comtessen_ (Berlin, 1885, 5th ed. 1898), _Unsühnbar_ (1890,
+5th ed. 1900) and _Glaubenslos?_ (1893) the life of the Austrian
+aristocracy in town and country. She also published _Neue Erzählungen_
+(Berlin, 1881, 3rd ed. 1894), _Aphorismen_ (Berlin, 1880, 4th ed. 1895)
+and _Parabeln, Märchen und Gedichte_ (2nd ed., Berlin, 1892). Frau von
+Ebner-Eschenbach's elegance of style, her incisive wit and masterly
+depiction of character give her a foremost place among the German
+women-writers of her time. On the occasion of her seventieth birthday the
+university of Vienna conferred upon her the degree of doctor of
+philosophy, _honoris causa_.
+
+  An edition of Marie von Ebner-Eschenbach's _Gesammelte Schriften_
+  began to appear in 1893 (Berlin). See A. Bettelheim, _Marie von
+  Ebner-Eschenbach: biographische Blätter_ (Berlin, 1900), and M.
+  Necker, _Marie von Ebner-Eschenbach, nach ihren Werken geschildert_
+  (Berlin, 1900).
+
+
+
+
+EBOLI (anc. _Eburum_), a town of Campania, Italy, in the province of
+Salerno, from which it is 16 m. E. by rail, situated 470 ft. above
+sea-level, on the S. edge of the hills overlooking the valley of the
+Sele. Pop. (1901) 9642 (town), 12,423 (commune). The sacristy of St
+Francesco contains two 14th-century pictures, one by Roberto da Oderisio
+of Naples. The ancient Eburum was a Lucanian city, mentioned only by
+Pliny and in inscriptions, not far distant from the Campanian border. It
+lay above the Via Popillia, which followed the line taken by the modern
+railway. Some scanty remains of its ancient polygonal walls may still be
+seen.     (T. As.)
+
+
+
+
+EBONY (Gr. [Greek: ebenos]), the wood of various species of trees of the
+genus _Diospyros_ (natural order Ebenaceae), widely distributed in the
+tropical parts of the world. The best kinds are very heavy, are of a
+deep black, and consist of heart-wood only. On account of its colour,
+durability, hardness and susceptibility of polish, ebony is much used
+for cabinet work and inlaying, and for the manufacture of
+pianoforte-keys, knife-handles and turned articles. The best Indian and
+Ceylon ebony is furnished by _D. Ebenum_, a native of southern India and
+Ceylon, which grows in great abundance throughout the flat country west
+of Trincomalee. The tree is distinguished from others by the inferior
+width of its trunk, and its jet-black, charred-looking bark, beneath
+which the wood is perfectly white until the heart is reached. The wood
+is stated to excel that obtained from _D. reticulata_ of the Mauritius
+and all other varieties of ebony in the fineness and intensity of its
+dark colour. Although the centre of the tree alone is employed, reduced
+logs 1 to 3 ft. in diameter can readily be procured. Much of the East
+Indian ebony is yielded by the species _D. Melanoxylon_ (Coromandel
+ebony), a large tree attaining a height of 60 to 80 ft., and 8 to 10 ft.
+in circumference, with irregular rigid branches, and oblong or
+oblong-lanceolate leaves. The bark of the tree is astringent, and mixed
+with pepper is used in dysentery by the natives of India. The wood of
+_D. tomentosa_, a native of north Bengal, is black, hard and of great
+weight. _D. montana_, another Indian species, produces a yellowish-grey
+soft but durable wood. _D. quaesita_ is the tree from which is obtained
+the wood known in Ceylon by the name _Calamander_, derived by Pridham
+from the Sinhalee _kalumindrie_, black-flowing. Its closeness of grain,
+great hardness and fine hazel-brown colour, mottled and striped with
+black, render it a valuable material for veneering and furniture making.
+_D. Dendo_, a native of Angola, is a valuable timber tree, 25 to 35 ft.
+high, with a trunk 1 to 2 ft. in diameter. The heart-wood is very black
+and hard and is known as black ebony, also as billet-wood, and Gabun,
+Lagos, Calabar or Niger ebony. What is termed Jamaica or West Indian
+ebony, and also the green ebony of commerce, are produced by _Brya
+Ebenus_, a leguminous tree or shrub, having a trunk rarely more than 4
+in. in diameter, flexible spiny branches, and orange-yellow,
+sweet-scented flowers. The heart-wood is rich dark brown in colour,
+heavier than water, exceedingly hard and capable of receiving a high
+polish.
+
+From the book of Ezekiel (xxvii. 15) we learn that ebony was among the
+articles of merchandise brought to Tyre; and Herodotus states (iii. 97)
+that the Ethiopians every three years sent a tribute of 200 logs of it
+to Persia. Ebony was known to Virgil as a product of India (_Georg._ ii.
+116), and was displayed by Pompey the Great in his Mithradatic triumph
+at Rome. By the ancients it was esteemed of equal value for durability
+with the cypress and cedar (see Pliny, _Nat. Hist._ xii. 9, xvi. 79).
+According to Solinus (_Polyhistor_, cap. lv. p. 353, Paris, 1621), it
+was employed by the kings of India for sceptres and images, also, on
+account of its supposed antagonism to poison, for drinking-cups. The
+hardness and black colour of the wood appear to have given rise to the
+tradition related by Pausanias, and alluded to by Southey in _Thalaba_,
+i. 22, that the ebony tree produced neither leaves nor fruit, and was
+never seen exposed to the sun.
+
+
+
+
+EBRARD, JOHANNES HEINRICH AUGUST (1818-1888), German theologian, was
+born at Erlangen on the 18th of January 1818. He was educated in his
+native town and at Berlin, and after teaching in a private family became
+_Privatdocent_ at Erlangen (1841) and then professor of theology at
+Zürich (1844). In 1847 he was appointed professor of theology at
+Erlangen, a chair which he resigned in 1861; in 1875 he became pastor of
+the French reformed church in the same city. As a critic Ebrard occupied
+a very moderate standpoint; as a writer his chief works were
+_Christliche Dogmatik_ (2 vols., 1851), _Vorlesungen über praktische
+Theologie_ (1864), _Apologetik_ (1874-1875, Eng. trans. 1886). He also
+edited and completed H. Olshausen's commentary, himself writing the
+volumes on the Epistle to the Hebrews, the Johannine Epistles, and
+Revelation. In the department of belles-lettres he wrote a good deal
+under such pseudonyms as Christian Deutsch, Gottfried Flammberg and
+Sigmund Sturm. He died at Erlangen on the 23rd of July 1888.
+
+
+
+
+EBRO (anc. _Iberus_ or _Hiberus_), the only one of the five great rivers
+of the Iberian Peninsula (Tagus, Douro, Ebro, Guadalquivir, Guadiana)
+which flows into the Mediterranean. The Ebro rises at Fuentibre, a
+hamlet among the Cantabrian Mountains, in the province of Santander; at
+Reinosa, 4 m. east, it is joined on the right by the Hijar, and thus
+gains considerably in volume. It flows generally east by south through a
+tortuous valley as far as Miranda de Ebro, passing through the
+celebrated Roman bridge known as La Horadada ("the perforated"), near
+Oña in Burgos. From Miranda it winds south-eastward through the wide
+basin enclosed on the right by the highlands of Old Castile and western
+Aragon, and on the left by the Pyrenees. The chief cities on its banks
+are Logroño, Calahorra, Tudela, Saragossa and Caspe. Near Mora in
+Catalonia it forces a way through the coastal mountains, and, passing
+Tortosa, falls into the Mediterranean about 80 m. south-west of
+Barcelona, after forming by its delta a conspicuous projection on the
+otherwise regular coast line. In its length, approximately 465 m., the
+Ebro is inferior to the Tagus, Guadiana and Douro; it drains an area of
+nearly 32,000 sq. m. Its principal tributaries are--from the right hand
+the Jalon with its affluent the Jiloca, the Huerva, Aguas, Martin,
+Guadalope and Matarraña; from the left the Ega, Aragon, Arba, Gallego,
+and the Segre with its intricate system of confluent rivers. The Ebro
+and its tributaries have been utilized for irrigation since the Moorish
+conquest; the main stream becomes navigable by small boats about Tudela;
+but its value as a means of communication is almost neutralized by the
+obstacles in its channel, and seafaring vessels cannot proceed farther
+up than Tortosa. The great Imperial Canal, begun under the emperor
+Charles V. (1500-1558), proceeds along the right bank of the river from
+a point about 3 m. below Tudela, to El Burgo de Ebro, 5 m. below
+Saragossa; the irrigation canal of Tauste skirts the opposite bank for a
+shorter distance; and the San Carlos or New Canal affords direct
+communication between Amposta at the head of the delta and the harbour
+of Los Alfaques. From Miranda to Mora the Bilbao-Tarragona railway
+follows the course of the Ebro along the right bank.
+
+
+
+
+EBROÏN (d. 681), Frankish "mayor of the palace," was a Neustrian, and
+wished to impose the authority of Neustria over Burgundy and Austrasia.
+In 656, at the moment of his accession to power, Sigebert III., the king
+of Austrasia, had just died, and the Austrasian mayor of the palace,
+Grimoald, was attempting to usurp the authority. The great nobles,
+however, appealed to the king of Neustria, Clovis II., and unity was
+re-established. But in spite of a very firm policy Ebroïn was unable to
+maintain this unity, and while Clotaire III., son of Clovis II., reigned
+in Neustria and Burgundy, he was obliged in 660 to give the Austrasians
+a special king, Childeric II., brother of Clotaire III., and a special
+mayor of the palace, Wulfoald. He endeavoured to maintain at any rate
+the union of Neustria and Burgundy, but the great Burgundian nobles
+wished to remain independent, and rose under St Leger (Leodegar), bishop
+of Autun, defeated Ebroïn, and interned him in the monastery of Luxeuil
+(670). A proclamation was then issued to the effect that each kingdom
+should keep its own laws and customs, that there should be no further
+interchange of functionaries between the kingdoms, and that no one
+should again set up a tyranny like that of Ebroïn. Soon, however, Leger
+was defeated by Wulfoald and the Austrasians, and was himself confined
+at Luxeuil in 673. In the same year, taking advantage of the general
+anarchy, Ebroïn and Leger left the cloister and soon found themselves
+once more face to face. Each looked for support to a different
+Merovingian king, Ebroïn even proclaiming a false Merovingian as
+sovereign. In this struggle Leger was vanquished; he was besieged in
+Autun, was forced to surrender and had his eyes put out, and, on the
+12th of October 678, he was put to death after undergoing prolonged
+tortures. The church honours him as a saint. After his death Ebroïn
+became sole and absolute ruler of the Franks, imposing his authority
+over Burgundy and subduing the Austrasians, whom he defeated in 678 at
+Bois-du-Fay, near Laon. His triumph, however, was short-lived; he was
+assassinated in 681, the victim of a combined attack of his numerous
+enemies. He was a man of great energy, but all his actions seem to have
+been dictated by no higher motives than ambition and lust of power.
+
+  See _Liber historiae Francorum_, edited by B. Krusch, in _Mon. Germ.
+  hist. script. rer. Merov._ vol. ii.; _Vita sancti Leodegarii_, by
+  Ursinus, a monk of St Maixent (Migne, _Patr. Latina_, vol. xcvi.);
+  "Vita metrica" in _Poetae Latini aevi Carolini_, vol. iii. (_Mon.
+  Germ. hist._); J.B. Pitra, _Histoire de Saint Léger_ (Paris, 1846);
+  and J. Friedrich, "Zur Gesch. des Hausmeiers Ebroïn," in the
+  _Proceedings of the Academy of Munich_ (1887, pp. 42-61).
+       (C. Pf.)
+
+
+
+
+EBURACUM, or EBORACUM (probably a later variant), the Roman name of York
+(q.v.) in England. Established about A.D. 75-80 as fortress of the
+Ninth legion and garrisoned (after the annihilation of that legion about
+A.D. 118) by the Sixth legion, it developed outside its walls a town of
+civil life, which later obtained Roman municipal rank and in the 4th
+century was the seat of a Christian bishop. The fortress and town were
+separated by the Ouse. On the left bank, where the minster stands, was
+the fortress, of which the walls can still be partly traced, and one
+corner (the so-called Multangular Tower) survives. The municipality
+occupied the right bank near the present railway station. The place was
+important for its garrison and as an administrative centre, and the town
+itself was prosperous, though probably never very large. The name is
+preserved in the abbreviated form Ebor in the official name of the
+archbishop of York, but the philological connexion between Eboracum and
+the modern name York is doubtful and has probably been complicated by
+Danish influence.     (F. J. H.)
+
+
+
+
+EÇA DE QUEIROZ, JOSÉ MARIA (1843-1900), Portuguese writer, was born at
+the northern fishing town of Povoa de Varzim, his father being a retired
+judge. He went through the university of Coimbra, and on taking his
+degree in law was appointed Administrador de Concelho at Leiria, but
+soon tired of the narrow mental atmosphere of the old cathedral town and
+left it. He accompanied the Conde de Rezende to Egypt, where he assisted
+at the opening of the Suez Canal, and to Palestine, and on his return
+settled down to journalism in Lisbon and began to evolve a style, at
+once magical and unique, which was to renovate his country's prose.
+Though he spent much of his days with the philosopher sonneteer Anthero
+de Quental, and the critic Jayme Batalha Reis, afterwards consul-general
+in London, he did not restrict his intimacy to men of letters, but
+frequented all kinds of society, acquiring a complete acquaintance with
+contemporary Portuguese life and manners. Entering the consular service
+in 1872, he went to Havana, and, after a tour in the United States, was
+transferred two years later to Newcastle-on-Tyne and in 1876 to Bristol.
+In 1888 he became Portuguese consul-general in Paris, and there died in
+1900.
+
+Queiroz made his literary début in 1870 by a sensational story, _The
+Mystery of the Cintra Road_, written in collaboration with the art
+critic Ramalho Ortigão, but the first publication which brought him fame
+was _The Farpas_, a series of satirical and humorous sketches of various
+phases of social life, which, to quote the poet Guerra Junqueiro,
+contain "the epilepsy of talent." These essays, the joint production of
+the same partners, criticized and ridiculed the faults and foibles of
+every class in turn, mainly by a comparison with the French, for the
+education of Queiroz had made him a Frenchman in ideas and sympathies.
+His Brazilian friend, Eduardo Prado, bears witness that at this period
+French literature, especially Hugo's verse, and even French politics,
+interested Queiroz profoundly, while he altogether ignored the
+_belles-lettres_ of his own country and its public affairs. This phase
+lasted for some years, and even when he travelled in the East he was
+inclined to see it with the eyes of Flaubert, though the publication of
+_The Relic_ and that delightful prose poem _Sweet Miracle_ afterwards
+showed that he had been directly impressed and deeply penetrated by its
+scenery, poetry and mysticism. The Franco-German War of 1870, however,
+by lowering the prestige of France, proved the herald of a national
+Portuguese revival, and had a great influence on Queiroz, as also had
+his friend Oliveira Martins (q.v.), the biographer of the patriot kings
+of the Aviz dynasty. He founded the Portuguese Realist-Naturalist
+school, of which he remained for the rest of his life the chief
+exponent, by a powerful romance, _The Crime of Father Amaro_, written in
+1871 at Leiria but only issued in 1875. Its appearance then led to a
+baseless charge that he had plagiarized _La Faute de l'Abbé Mouret_, and
+ill-informed critics began to name Queiroz the Portuguese Zola, though
+he clearly occupied an altogether different plane in the domain of art.
+During his stay in England he produced two masterpieces, _Cousin Basil_
+and _The Maias_, but they show no traces of English influence, nor again
+are they French in tone, for, living near to France, his disillusionment
+progressed and was completed when he went to Paris and had to live under
+the régime of the Third Republic. Settling at Neuilly, the novelist
+became chronicler, critic, and letter-writer as well, and in all these
+capacities Queiroz displayed a spontaneity, power and artistic finish
+unequalled in the literature of his country since the death of Garrett.
+A bold draughtsman, he excelled in freshness of imagination and careful
+choice and collocation of words, while his warmth of colouring and
+brilliance of language speak of the south. Many of his pages descriptive
+of natural scenery, such for instance as the episode of the return to
+Tormes in _The City and the Mountains_, have taken rank as classic
+examples of Portuguese prose, while as a creator of characters he stood
+unsurpassed by any writer of his generation in the same field. He
+particularly loved to draw and judge the middle class, and he mocks at
+and chastises its hypocrisy and narrowness, its veneer of religion and
+culture, its triumphant lying, its self-satisfied propriety, its cruel
+egotism. But though he manifested a predilection for middle-class types,
+his portrait gallery comprises men and women of all social conditions.
+_The Maias_, his longest book, treats of _fidalgos_, while perhaps his
+most remarkable character study is of a servant, Juliana, in _Cousin
+Basil_. At least two of his books, this latter and _The Crime of Father
+Amaro_, are _chroniques scandaleuses_ in their plots and episodes; these
+volumes, however, mark not only the high-water line of the
+Realist-Naturalist school in Portugal, but are in themselves, leaving
+aside all accidentals, creative achievements of a high order.
+
+Though Queiroz was a keen satirist of the ills of society, his pages
+show hardly a trace of pessimism. _The City and the Mountains_, and in
+part _The Relic_ also, reveal the apostle of Realism as an idealist and
+dreamer, a true representative of that Celtic tradition which survives
+in the race and has permeated the whole literature of Portugal. _The
+Mandarin_, a fantastic variation on the old theme of a man self-sold to
+Satan, and _The Illustrious House of Ramires_, are the only other
+writings of his that require mention, except _The Correspondence of
+Fradique Mendes_. In conjunction with Anthero de Quental and Jayme
+Batalha Reis, Queiroz invented under that name a smart man of the world
+who had something of himself and something of Eduardo Prado, and made
+him correspond on all sorts of subjects with imaginary friends and
+relatives to the delight of the public, many of whom saw in him a
+mysterious new writer whose identity they were eager to discover. These
+sparkling and humorous letters are an especial favourite with admirers
+of Queiroz, because they reveal so much of his very attractive
+personality, and perhaps the cleverest of the number, that on Pacheco,
+has received an English dress. In addition to his longer and more
+important works, Queiroz wrote a number of short stories, some of which
+have been printed in a volume under the title of _Contos_. The gems of
+this remarkable collection are perhaps _The Peculiarities of a
+Fair-haired Girl_, _A Lyric Poet_, _José Matthias_, _The Corpse_, and
+_Sweet Miracle_.
+
+  Most of his books have gone through many editions, and they are even
+  more appreciated in the Brazils than in Portugal. It should be
+  mentioned that the fourth edition of _Father Amaro_ is entirely
+  different in form and action from the first, the whole story having
+  been rewritten. One of Queiroz's romances and two of his short stories
+  have been published in English. An unsatisfactory version of _Cousin
+  Basil_, under the title _Dragon's Teeth_, appeared at Boston, U.S.A.,
+  in 1889, while _Sweet Miracle_ has had three editions in England and
+  one in America, and there is also a translation of _O Defunto_ (_The
+  Corpse_) under the name of _Our Lady of the Pillar_.
+
+  An admirable critical study of the work of Queiroz will be found in _A
+  Geração Nova--Os Novellistas_, by J. Pereira de Sampaio (_Bruno_),
+  (Oporto, 1886). The _Revista moderna_ of the 20th of November 1897 was
+  entirely devoted to him. Senhor Batalha Reis gives interesting
+  reminiscences of the novelist's early days in his preface to some
+  prose fragments edited by him and named _Prosas Barbaras_ (Oporto,
+  1903).     (E. Pr.)
+
+
+
+
+ÉCARTÉ (Fr. for "separated," "discarded"), a game at cards, of modern
+origin, probably first played in the Paris _salons_ in the first quarter
+of the 19th century. It is a development of a very old card game called
+_la triomphe_ or _French-ruff_. Écarté is generally played by two
+persons, but a pool of three may be formed, the player who is out taking
+the place of the loser, and the winner of two consecutive games winning
+the pool. At French écarté (but not at English) bystanders who are
+betting may advise the players, but only by pointing to the cards they
+desire them to play, and the loser of the game goes out, one of the
+_rentrants_ taking his place, unless the loser is playing _la chouette_,
+i.e. playing single-handed against two, and taking all bets.
+
+The small cards (from the two to the six, both inclusive) are removed
+from an ordinary pack. The players cut for deal, the highest having the
+choice. The king is the highest card, the ace ranking after the knave.
+The dealer gives five cards to his adversary, and five to himself, by
+two at a time to each and by three at a time to each, or vice versa. The
+eleventh card is turned up for trumps. If it is a king, the dealer
+scores one, at any time before the next deal. The non-dealer then looks
+at his cards. If satisfied with them he plays, and there is no
+discarding; if not satisfied he "proposes." The dealer may either accept
+or refuse. If he accepts, each player discards face downwards as many
+cards as he thinks fit, and fresh ones are given from the undealt cards
+or "stock," first to complete the non-dealer's hand to five, then to
+complete the dealer's. To ask for "a book" is to ask for five cards.
+Similarly a second proposal may be made, and so on, until one player is
+satisfied with his hand. If the dealer refuses, the hand is played
+without discarding. If the non-dealer announces that he holds the king
+of trumps, he scores one; and similarly, if the dealer holds the king
+and announces it, he scores one. The announcement must be made before
+playing one's first card, or if that card be the king, on playing it.
+The non-dealer, being satisfied with his hand, leads a card. The dealer
+plays a card to it, the two cards thus played forming a trick. The
+winner of the trick leads to the next, and so on. The second to play to
+a trick must follow suit if able, and must win the trick if he can.
+
+The scores are for the king and for the majority of tricks. The player
+who wins three tricks scores one for the "point"; if he wins all five
+tricks, he scores two for the "vole." If the non-dealer plays without
+proposing, or the dealer refuses the first proposal, and fails to win
+three tricks, the adversary scores two, but no more even if he wins the
+vole. The game is five up. The points are conveniently marked with a
+three-card and a two-card, as at euchre. The three is put face upwards
+with the two face downwards on the top of it. When one or two or three
+points are scored the top card is moved so as to expose them. At four,
+one pip of the two-card is put under the other card. Games may be
+recorded similarly.
+
+  _Hints to Players._--The following hints may be of service to
+  beginners:--
+
+  Shuffle thoroughly after every deal.
+
+  Do not announce the king until in the act of playing your first card.
+
+  The hands which should be played without proposing, called _jeux de
+  règle_ (standard hands), ought to be thoroughly known. They are as
+  follows:--
+
+  1. All hands with three or more trumps, whatever the other cards.
+
+  2. Hands with _two trumps_ which contain also--
+
+    (a) Any three cards of one plain suit;
+
+    (b) Two cards of one plain suit, one being as high as a queen;
+
+    (c) Two small cards of one suit, the fifth card being a king of
+    another suit;
+
+    (d) Three high cards of different suits.
+
+  3. Hands with _one trump_, which contain also--
+
+    (a) King, queen, knave of one suit, and a small card of another;
+
+    (b) Four cards of one suit headed by king;
+
+    (c) Three cards of one suit headed by queen, and queen of another
+    suit.
+
+  4. Hands with _no trump_, which contain three queens or cards of equal
+  value in different suits, e.g., four court cards.
+
+  5. Hands from which only two cards can be discarded without throwing a
+  king or a trump.
+
+  Holding cards which make the point certain, propose. If you hold a
+  _jeu de règle_, and one of the trumps is the king, propose, as your
+  adversary cannot then take in the king.
+
+  When discarding, throw out all cards except trumps and kings.
+
+  If your adversary proposes you should accept, unless you are guarded
+  in three suits (a queen being a sufficient guard), or in two suits
+  with a trump, or in one suit with two trumps. Hence the rule not to
+  discard two cards, unless holding the king of trumps, applies to the
+  dealer.
+
+  The hands with which to refuse are the same as those with which to
+  play without proposing, except as follows:--
+
+  1. Two trumps and three cards of one plain suit should not be played
+  unless the plain suit is headed by a court card.
+
+  2. One trump and a tierce major is too weak, unless the fifth card is
+  a court card. With similar hands weaker in the tierce major suit,
+  accept unless the fifth card is a queen.
+
+  3. One trump and four cards of a plain suit is too weak to play.
+
+  4. One trump and two queens is too weak, unless both queens are singly
+  guarded.
+
+  5. One trump, queen of one suit, and knave guarded of another should
+  not be played unless the queen is also guarded, or the card of the
+  fourth suit is a court card.
+
+  6. One trump, a king and a queen, both unguarded, should not be
+  played, unless the fourth suit contains a card as high as an ace.
+
+  7. Four court cards without a trump are too weak to play, unless they
+  are of three different suits.
+
+  Refuse with three queens, if two are singly guarded; otherwise,
+  accept.
+
+  Lead from your guarded suit, and lead the highest.
+
+  If the strong suit led is not trumped, persevere with it, unless with
+  king of trumps, or queen (king not having been announced), or knave
+  ace, when lead a trump before continuing your suit.
+
+  You should not lead trumps at starting, unless you hold king or queen,
+  knave, or knave ace, with court cards out of trumps.
+
+  The score has to be considered. If the dealer is at four, and the king
+  is not in your hand nor turned up, play any cards without proposing
+  which give an even chance of three tricks, e.g. a queen, a guarded
+  knave, and a guarded ten. The same rule applies to the dealer's
+  refusal.
+
+  At the adverse score of four, and king not being in hand or turned up,
+  any hand with one trump should be played, unless the plain cards are
+  very small and of different suits.
+
+  If the non-dealer plays without proposing when he is four to three,
+  and the dealer holds the king he ought not to mark it. The same rule
+  applies to the non-dealer after a refusal, if the dealer is four to
+  three.
+
+  At the score of non-dealer three, dealer four, the dealer should
+  refuse on moderate cards, as the player proposing at this score must
+  have a very bad hand.
+
+  At four a forward game should not be played in trumps, as there is no
+  advantage in winning the vole.
+
+  _Laws of Écarté._--The following laws are abridged from the revised
+  code adopted by the Turf Club:--A cut must consist of at least two
+  cards. Card exposed in cutting, fresh cut. Order of distribution of
+  cards, whether by three and two, or vice versa, once selected, dealer
+  must not change it during game. Player announcing king when he has not
+  got it, and playing a card without declaring error, adversary may
+  correct score and have hand played over again. If offender wins point
+  or vole that hand, he scores one less than he wins. Proposal,
+  acceptance, or refusal made cannot be retracted. Cards discarded must
+  not be looked at. Cards exposed in giving cards to non-dealer, he has
+  option of taking them or of having next cards; dealer exposing his own
+  cards, no penalty. Dealer turning up top card after giving cards,
+  cannot refuse second discard. Dealer accepting when too few cards in
+  stock to supply both, non-dealer may take cards, and dealer must play
+  his hand. Card led in turn cannot be taken up again. Card played to a
+  lead can only be taken up prior to another lead, to save revoke or to
+  correct error of not winning trick. Card led out of turn may be taken
+  up prior to its being played to. Player naming one suit and leading
+  another, adversary has option of requiring suit named to be led. If
+  offender has none, no penalty. Player abandoning hand, adversary is
+  deemed to win remaining tricks, and scores accordingly. If a player
+  revokes or does not win trick when he can do so, the adversary may
+  correct score and have hand replayed.
+
+  See _Académie des jeux_ (various editions after the first quarter of
+  the 19th century); Hoyle's _Games_ (various editions about the same
+  dates); Ch. Van-Tenac et Louis Delanoue, _Traité du jeu de l'écarté_
+  (Paris, 1845; translated in Bohn's _Handbook of Games_, London, 1850);
+  "Cavendish," _The Laws of Écarté, adopted by the Turf Club, with a
+  Treatise on the Game_ (London, 1878); _Pocket Guide to Écarté_
+  ("Cavendish," 1897); Foster's _Encyclopaedia of Indoor Games_ (1903).
+
+
+
+
+ECBATANA (_Agbatana_ in Aeschylus, _Hangmatana_ in Old Persian, written
+_Agamtanu_ by Nabonidos, and _Agamatanu_ at Behistun, mod. _Hamadan_),
+the capital of Astyages (Istuvegu), which was taken by Cyrus in the
+sixth year of Nabonidos (549 B.C.). The Greeks supposed it to be the
+capital of Media, confusing the Manda, of whom Astyages was king, with
+the Mada or Medes of Media Atropatene, and ascribed its foundation to
+Deioces (the _Daiukku_ of the cuneiform inscriptions), who is said to
+have surrounded his palace in it with seven concentric walls of
+different colours. Under the Persian kings, Ecbatana, situated at the
+foot of Mount Elvend, became a summer residence; and was afterwards the
+capital of the Parthian kings. Sir H. Rawlinson attempted to prove that
+there was a second and older Ecbatana in Media Atropatene, on the site
+of the modern Takht-i-Suleiman, midway between Hamadan and Tabriz
+(_J.R.G.S._ x. 1841), but the cuneiform texts imply that there was only
+one city of the name, and Takht-i-Suleiman is the Gazaca of classical
+geography. The Ecbatana at which Cambyses is said by Herodotus (iii. 64)
+to have died is probably a blunder for Hamath.
+
+  See Perrot and Chipiez, _History of Art in Persia_ (Eng. trans.,
+  1892); M. Dieulafoy, _L'Art antique de la Perse_, pt. i. (1884); J. de
+  Morgan, _Mission scientifique en Perse_, ii. (1894). See HAMADAN and
+  PERSIA: _Ancient History_, § v. 2.     (A. H. S.)
+
+
+
+
+ECCARD, JOHANN (1553-1611), German composer of church music, was born at
+Mühlhausen on the Unstrut, Prussia, in 1553. At the age of eighteen he
+went to Munich, where he became the pupil of Orlando Lasso. In his
+company Eccard is said to have visited Paris, but in 1574 we find him
+again at Mühlhausen, where he resided for four years, and edited,
+together with Johann von Burgk, his first master, a collection of sacred
+songs, called _Crepundia sacra Helmboldi_ (1577). Soon afterwards he
+obtained an appointment as musician in the house of Jacob Fugger, the
+Augsburg banker. In 1583 he became assistant conductor, and in 1599
+conductor, at Königsberg, to Georg Friedrich, margrave of
+Brandenburg-Anspach, the administrator of Prussia. In 1608 he was called
+by the elector Joachim Friedrich to Berlin as chief conductor, but this
+post he held only for three years, owing to his premature death at
+Königsberg in 1611. Eccard's works consist exclusively of vocal
+compositions, such as songs, sacred cantatas and chorales for four or
+five, and sometimes for seven, eight, or even nine voices. Their
+polyphonic structure is a marvel of art, and still excites the
+admiration of musicians. At the same time his works are instinct with a
+spirit of true religious feeling. His setting of the beautiful words
+"Ein' feste Burg ist unser Gott" is still regarded by the Germans as
+their representative national hymn. Eccard and his school are
+inseparably connected with the history of the Reformation.
+
+  Of Eccard's songs a great many collections are extant; see K.G.A. von
+  Winterfeld, _Der Evangelische Kirchengesang_ (1843); Döring
+  (_Choralkunde_, p. 47).
+
+
+
+
+ECCELINO [or EZZELINO] DA ROMANO (1194-1259), Ghibelline leader, and
+supporter of the emperor Frederick II., was born on the 25th of April
+1194. He belonged to a family descended from a German knight named
+Eccelin, who followed the emperor Conrad II. to Italy about 1036, and
+received the fief of Romano near Padua. Eccelin's grandson was Eccelino
+III., surnamed the Monk, who divided his lands between his two sons in
+1223, and died in 1235. The elder of these two sons was Eccelino, who in
+early life began to take part in family and other feuds, and in 1226, at
+the head of a band of Ghibellines, seized Verona and became _podestà_ of
+the city. He soon lost Verona, but regained it in 1230; and about this
+time came into relations with Frederick II., who in 1232 issued a
+charter confirming him in his possessions. In 1236 when besieged in
+Verona he was saved by the advance of the emperor, who in November of
+the same year took Vicenza and entrusted its government to Eccelino. In
+1237 he obtained authority over Padua and Treviso; and on the 27th of
+November in that year he shared in the victory gained by the emperor
+over the Lombards at Cortenuova. In 1238 he married Frederick's natural
+daughter, Selvaggia; in 1239 was appointed imperial vicar of the march
+of Treviso; but in the same year was excommunicated by Pope Gregory IX.
+He was constantly engaged in increasing his possessions; was present at
+the siege of Parma in 1247, and after Frederick's death in 1250 he
+supported his son, the German king Conrad IV. His cruelties had,
+however, aroused general disgust, and in 1254 he was again
+excommunicated. In 1256 Pope Alexander IV. proclaimed a crusade against
+him, and a powerful league was soon formed under the leadership of
+Philip, archbishop of Ravenna. Padua was taken from Eccelino, but on the
+1st of September 1258 he defeated his enemies at Torricella. He then
+made an attempt on Milan, and the rival forces met at Cassano on the
+27th of September 1259, when Eccelino was wounded and taken prisoner.
+Enraged at his capture, he tore the bandages from his wounds, refused to
+take nourishment, and died at Soncino on the 7th of October 1259. In the
+following year his brother Albert was put to death, and the Romano
+family became extinct. Eccelino, who is sometimes called the _tyrant_,
+acquired a terrible reputation on account of his cruelties, a reputation
+that won for him the immortality of inclusion in Dante's _Inferno_; but
+his unswerving loyalty to Frederick II. forms a marked contrast to the
+attitude of many of his contemporaries.
+
+Eccelino is the subject of a novel by Cesare Cantu and of a drama by J.
+Eichendorff.
+
+  See J.M. Gittermann, _Ezzelino da Romano_ (Freiburg, 1890); S. Mitis,
+  _Storia d' Ezzelino IV. da Romano_ (Maddaloni, 1896); and F. Stieve,
+  _Ezzelino von Romano_ (Leipzig, 1909).
+
+
+
+
+ECCENTRIC (from Gr. [Greek: ek], out of, and [Greek: kentron], centre),
+literally "out from the centre," and thus used to connote generally any
+deviation from the normal. In astronomy the word denotes a circle round
+which a body revolves, but whose centre is displaced from the visible
+centre of motion. In the ancient astronomy the ellipses in which it is
+now known that the planets revolve around the sun could not be
+distinguished from circles, but the unequal angular motion due to
+ellipticity was observed. The theory of the eccentric was that the
+centre of the epicycle of each planet moved uniformly in a circle, the
+centre of which was displaced from that of the earth by an amount double
+the eccentricity of the actual ellipse, as the case is now understood.
+When measured around this imaginary centre, which is so situated on the
+major axis of the ellipse that the focus, or place of the real sun, is
+midway between it and the centre of the ellipse, the motion is
+approximately uniform. In engineering, an eccentric is a mechanical
+device for converting rotary into reciprocating motion (see
+STEAM-ENGINE). For eccentric angle see ELLIPSE.
+
+
+
+
+ECCHELLENSIS (or ECHELLENSIS), ABRAHAM (d. 1664), a learned Maronite,
+whose surname is derived from Eckel in Syria, where he was born towards
+the close of the 16th century. He was educated at the Maronite college
+in Rome, and, after taking his doctor's degree in theology and
+philosophy, returned for a time to his native land. He then became
+professor of Arabic and Syriac in the college of the Propaganda at Rome.
+Called to Paris in 1640 to assist Le Jay in the preparation of his
+polyglot Bible, he contributed to that work the Arabic and Latin
+versions of the book of Ruth and the Arabic version of the third book of
+Maccabees. In 1646 he was appointed professor of Syriac and Arabic at
+the Collège de France. Being invited by the Congregation of the
+Propaganda to take part in the preparation of an Arabic version of the
+Bible, Ecchellensis went again in 1652 or 1653 to Rome. He published
+several Latin translations of Arabic works, of which the most important
+was the _Chronicon Orientale_ of Ibnar-Rahib (Paris, 1653), a history of
+the patriarchs of Alexandria. He was engaged in an interesting
+controversy with John Selden as to the historical grounds of episcopacy,
+in the course of which he published his _Eutychius vindicatus, sive
+Responsio ad Seldeni Origines_ (Rome, 1661). Conjointly with Giovanni
+Borelli he wrote a Latin translation of the 5th, 6th and 7th books of
+the _Conics_ of Apollonius of Perga (1661). He died at Rome in 1664.
+
+
+
+
+ECCLES, a municipal borough in the Eccles parliamentary division of
+Lancashire, England, 4 m. W. of Manchester, of which it forms
+practically a suburb. Pop. (1901) 34,369. It is served by the London &
+North-Western railway and by the Birkenhead railway (North-Western and
+Great Western joint). The Manchester Ship Canal passes through. The
+church of St Mary is believed to date from the 12th century, but has
+been enlarged and wholly restored in modern times. There are several
+handsome modern churches and chapels, a town hall, and numerous cotton
+mills, while silk-throwing and the manufacture of fustians and ginghams
+are also among the industries, and there are also large engine works. A
+peculiar form of cake is made here, taking name from the town, and has a
+wide reputation. Eccles was incorporated in 1892, and the corporation
+consists of a mayor, 6 aldermen and 18 councillors. The borough
+maintains the tramway service, &c., but water and gas are supplied from
+Manchester and Salford respectively. Area, 2057 acres.
+
+Before the Reformation the monks of Whalley Abbey had a grange here at
+what is still called Monks' Hall; and in 1864 many thousands of silver
+pennies of Henry III. and John of England and William I. of Scotland
+were discovered near the spot. Robert Ainsworth, the author of the Latin
+and English dictionary so long familiar to English students, was born at
+Eccles in 1660; and it was at the vicarage that William Huskisson
+expired on the 15th of September 1830 from injuries received at the
+opening of the Liverpool & Manchester railway. From early times "wakes"
+were held at Eccles, and bull-baiting, bear-baiting and cock-fighting
+were carried on. Under Elizabeth these festivals, which had become
+notoriously disorderly, were abolished, but were revived under James I.,
+and maintained until late in the 19th century on public ground. The
+cockpit remained on the site of the present town hall. A celebration on
+private property still recalls these wakes.
+
+
+
+
+ECCLESFIELD, a township in the Hallamshire parliamentary division of the
+West Riding of Yorkshire, England, 5 m. N. of Sheffield, on the Great
+Central and Midland railways. The church of St Mary is Perpendicular,
+with a central tower, and contains excellent woodwork. It formerly bore,
+and must have deserved, the familiar title of the "Minster of the
+Moors." Ecclesfield was the seat of a Benedictine priory, which passed
+to the Carthusians in the 14th century. Cutlery and tools are largely
+manufactured, and there are coal-mines, paper mills and iron and
+fire-clay works. After the inclusion within the county borough of
+Sheffield of part of the civil parish of Ecclesfield in 1901, the
+population was 18,324.
+
+
+
+
+ECCLESHALL, a market town in the north-western parliamentary division of
+Staffordshire, England; 7 m. N.W. from Stafford, and 4 W. of Norton
+Bridge station on the London & North-Western main line. Pop. (1901)
+3799. The church of the Holy Trinity, one of the most noteworthy in
+Staffordshire, is principally Early English, and has fine stained glass.
+Several bishops of Lichfield are buried here, as Eccleshall Castle was
+the episcopal residence from the 13th century until 1867. Of this the
+ancient remains include a picturesque tower and bridge. To the west on
+the borders of Shropshire is Blore Heath, the scene of a defeat of the
+Lancastrians by the Yorkists in 1459.
+
+
+
+
+ECCLESIA (Gr. [Greek: ekklêsia], from [Greek: ek], out, and [Greek:
+kalein], to call), in ancient Athens, the general assembly of all the
+freemen of the state. In the primitive unorganized state the king was
+theoretically absolute, though his great nobles meeting in the Council
+(see BOULE) were no doubt able to influence him considerably. There is,
+however, no doubt that in the earliest times the free people, i.e. the
+fighting force of the state, were called together to ratify the
+decisions of the king, and that they were gradually able to enforce
+their wishes against those of the nobles. In Athens, as in Rome, where
+the Plebs succeeded in their demand for the codification of the laws
+(the Twelve Tables), it was no doubt owing to the growing power of the
+people meeting in the Agora that Draco was entrusted with the task of
+publishing a code of law and so putting an end to the arbitrary
+judicature of the aristocratic party. But there is no evidence that the
+Ecclesia had more than a _de facto_ existence before Solon's reforms.
+
+The precise powers which Solon gave the people are not known. It is
+clear that the executive power in the state (see ARCHON) was still
+vested in the Eupatrid class. It is obvious, therefore, that a moderate
+reformer would endeavour to give to the people some control over the
+magistracy. Now in speaking of the Thetes (the lowest of the four
+Solonian classes; see SOLON), Aristotle's _Constitution of Athens_ says
+that Solon gave them merely "a share in the Ecclesia and the Law
+Courts," and in the _Politics_ we find that he gave them the right of
+electing the magistrates and receiving their accounts at the end of the
+official year. Thus it seems that the "mixed" character of Solon's
+constitution consisted in the fact that though the officials of the
+state were still necessarily Eupatrid, the Ecclesia elected those of the
+Eupatrids whom they could trust, and further had the right of
+criticizing their official actions. Secondly, all our accounts agree
+that Solon admitted the Thetes to the Ecclesia, thus recognizing them as
+citizens. Under Cleisthenes the Ecclesia remained the sovereign power,
+but the Council seems to have become to some extent a separate
+administrative body. The relation of Boule and Ecclesia in the
+Cleisthenic democracy was of the greatest importance. The Ecclesia
+alone, a heterogeneous body of untrained citizens, could not have
+passed, nor even have drawn up intelligible measures; all the
+preliminary drafting was done by the small committee of the Boule which
+was in session at any particular time. In the 5th century the functions
+of the Ecclesia and the popular courts of justice were vastly increased
+by the exigencies of empire. At the beginning of the 4th century B.C.
+the system of payment was introduced (see below). In 308 B.C. Demetrius
+of Phalerum curtailed the power of the Ecclesia by the institution of
+the _Nomophylaces_ (Guardians of the Law), who prevented the Ecclesia
+from voting on an illegal or injurious motion. Under Roman rule the
+powers of the Ecclesia and the popular courts were much diminished, and
+after 48 B.C. (the franchise being frequently sold to any casual alien)
+the Demos (people) was of no importance. They still assembled to pass
+psephisms in the theatre and to elect strategi, and, under Hadrian, had
+some small judicial duties, but as a governing body the Ecclesia died
+when Athens became a _civitas libera_ under Roman protection.
+
+_Constitution and Functions._--Throughout the period of Athenian
+greatness the Ecclesia was the sovereign power, not only in practice but
+also in theory. The assembly met in early times near the sanctuary of
+Aphrodite Pandemus (i.e. south of the Acropolis), but, in the 5th and
+4th centuries, the regular place of meeting was the Pnyx. From the 5th
+century it met sometimes in the theatre, which in the 3rd century was
+the regular place. From Demosthenes we learn that in his time special
+meetings were held at Peiraeus, and, in the last centuries B.C.,
+meetings were held at Athens and Peiraeus alternately. Certain meetings,
+however, for voting ostracism (q.v.) and on questions affecting
+individual status took place in the Agora. Meetings were (1) ordinary,
+(2) extraordinary, and (3) convened by special messengers ([Greek:
+kyriai], [Greek: synklêtoi] and [Greek: kataklêtoi]), these last being
+called when it was desirable that the country people should attend. At
+ordinary meetings the attendance was practically confined to Athenian
+residents. According to Aristotle there were four regular meetings in
+each prytany (see BOULE); probably only the first of these was called
+[Greek: kyria]. It is certain, however, that the four meetings did not
+fall on regular days, owing to the occurrence of feast days on which no
+meeting could take place. In the [Greek: kyria ekklêsia] of each month
+took place the _Epicheirotonia_ (monthly inquiry) of the state
+officials, and if it proved unsatisfactory a trial before the Heliaea
+was arranged; the council reported on the general security and the
+corn-supply, and read out lists of vacant inheritances and unmarried
+heiresses. In the sixth prytany of each year at the [Greek: kyria
+ekklêsia] the question whether ostracism should take place that year was
+put to the vote. For all meetings it was usual that the Prytaneis should
+give five days' notice in the form of a _programma_ (agenda). On
+occasions of sudden importance the herald of the council summoned the
+people with a trumpet, and sometimes special messengers were despatched
+to "bring in" the country people ([Greek: katakalein]).
+
+After the archonship of Solon all Athenians over the age of eighteen
+were eligible to attend the assembly, save those who for some reason had
+suffered _atimia_ (loss of civil rights). To prevent the presence of any
+disqualified persons, six _lexiarchs_ with thirty assistants were
+present with the deme-rolls in their hands. These officers superintended
+the payment in the 4th century and probably the _toxotae_ (police) also,
+whose duty it was before the introduction of pay to drive the people out
+of the Agora into the Ecclesia with a rope steeped in red dye which they
+stretched out and used as a draw net (see Aristoph. _Acharn._ 22 and
+_Eccles._ 378). The introduction of pay, which belongs to the early
+years of the 4th century and by the _Constitution_ (c. 41 ad fin.) is
+attributed to Agyrrhius, a statesman of the restored democracy, was a
+device to secure a larger attendance. The rate rose from one to two
+obols and then to three obols (Aristoph. _Eccles._ 300 sqq.), while at
+the time of Aristotle it was one and a half drachmas for the [Greek:
+kyria ekklêsia] and one drachma for other meetings. Probably those who
+were late did not receive payment.
+
+_Procedure._--The proceedings opened with formalities: the purification
+by the _peristiarchs_, who carried round slain sucking pigs; the curse
+against all who should deceive the people; the appointment (in the 4th
+century) of the _proedri_ and their _epistates_ (see BOULE); the report
+as to the weather-omens. The assembly was always dismissed if there were
+thunder, rain or an eclipse. These formalities over, the Prytaneis
+communicated the _probouleuma_ of the council, without which the
+Ecclesia could not debate. This recommendation either submitted definite
+proposals or merely brought the agenda before the assembly. Its
+importance lay largely in the fact that it _explained_ the business in
+hand, which otherwise must often have been beyond the grasp of a
+miscellaneous assembly. After the reading, a preliminary vote was taken
+as to whether the council's report should be accepted _en bloc_. If it
+was decided to discuss, the herald called upon people to speak. Any
+person, without distinction of age or position, might obtain leave to
+speak, but it seems probable that the man who had moved the
+recommendation previously in the council would advocate it in the
+assembly. The council was, therefore, a check on the assembly, but its
+powers were to some extent illusory, because any member of the assembly
+(1) might propose an amendment, (2) might draw up a new resolution
+founded on the principal motion, (3) might move the rejection of the
+motion and the substitution of another, (4) might bring in a motion
+asking the council for a recommendation on a particular matter, (5)
+might petition the council for leave to speak on a given matter to the
+assembly. Voting usually was by show of hands, but in special cases
+(ostracism, &c.) by ballot (i.e. by casting pebbles into one of two
+urns). The decision of the assembly was called a _psephism_ and had
+absolute validity. These decisions were deposited in the Metroön where
+state documents were preserved; peculiarly important decrees were
+inscribed also on a column (_stele_) erected on the Acropolis. It has
+been shown that the power of the council was far from sufficient. The
+real check on the vagaries of amateur legislators was the Graphe
+Paranomon. Any man was at liberty to give notice that he would proceed
+against the mover of a given resolution either before or after the
+voting in the Ecclesia. A trial in a Heliastic court was then arranged,
+and the plaintiff had to prove that the resolution in question
+contravened an existing law. If this contention were upheld by the
+court, when the case was brought to it by the Thesmothetae, the
+resolution was annulled, and the defendant had to appear in a new trial
+for the assessment of the penalty, which was usually a fine, rarely
+death. Three convictions under this law, however, involved a certain
+loss of rights; the loser could no longer move a resolution in the
+Ecclesia. After the lapse of a year the mover of a resolution could not
+be attacked. In the 4th century the Graphe Paranomon took the place of
+Ostracism (q.v.). In the 5th century it was merely an arrangement
+whereby the people sitting as sworn juries ratified or annulled their
+own first decision in the Ecclesia.
+
+_Revision of Laws._--In the 4th century, the assembly annually, on the
+eleventh day of Hecatombaeon (the first day of the official year), took
+a general vote on the laws, to decide whether revision was necessary. If
+the decision was in favour of alteration, it was open to any private
+citizen to put up notice of amendments. The Nomothetae, a panel selected
+by the Prytaneis from the Heliaea, heard arguments for and against the
+changes proposed and voted accordingly. Against all new laws so passed,
+there lay the Graphe; Paranomon. Thus the Nomothetae, not the Ecclesia,
+finally passed the law.
+
+_Judicial Functions._--The Ecclesia heard cases of Probole and
+Eisangelia (see GREEK LAW). The Probole was an action against sycophants
+and persons who had not kept their promises to the people, or had
+disturbed a public festival. The verdict went by show of hands, but no
+legal consequences ensued; if the plaintiff demanded punishment he had
+to go to the Heliaea which were not at all bound by the previous vote in
+the Ecclesia. Cases of Eisangelia in which the penalty exceeded the
+legal competence of the council came before the Ecclesia in the form of
+a _probouleuma_. To prevent vexatious accusations, it was (at some date
+unknown) decided that the accuser who failed to obtain one-fifth of the
+votes should be fined 1000 drachmas (£40). (For the procedure in case of
+OSTRACISM see that article.)
+
+_Summary._--Thus it will be seen that the Ecclesia, with no formal
+organization, had absolute power save for the Graphe Paranomon (which,
+therefore, constituted the dicasteries in one sense the sovereign power
+in the state). It dealt with all matters home and foreign. Every member
+could initiate legislation, and, as has been shown, the power of the
+council was merely formal. As against this it must be pointed out that
+it was by no means a representative assembly in practice. The phrase
+used to describe a very special assembly ([Greek: kataklêtos ekklêsia])
+shows that ordinarily the country members did not attend ([Greek:
+katakalein] always involving the idea of motion from a distance towards
+Athens), and Thucydides says that 5000 was the maximum attendance,
+though it must be remembered that he is speaking of the time when the
+number of citizens had been much reduced owing to the plague and the
+Sicilian expedition. From this we understand the necessity of payment in
+the 4th century, although in that period the Ecclesia was supreme
+(_Constitution of Athens_, xli. 2). The functions of the Ecclesia thus
+differed in two fundamental respects from those which are in modern
+times associated with a popular assembly. (1) It did not exercise, at
+least in the period as to which we are best instructed, the power of
+law-making ([Greek: nomothesia]) in the strict sense. It must be
+remembered, however, in qualification of this statement that it
+possessed the power of passing _psephismata_ which would in many cases
+be regarded as law in the modern sense. (2) The Ecclesia was principally
+concerned with the supervision of administration. Much of what we regard
+as executive functions were discharged by the Ecclesia.
+
+  With this article compare those on SOLON; BOULE; AREOPAGUS; GREEK LAW,
+  and, for other ancient popular assemblies, APELLA; COMITIA. See also
+  A.H.J. Greenidge, _Handbook of Greek Constitutional History_ (1896);
+  Gilbert, _Greek Constitutional Antiquities_ (trans. Brooks and
+  Nicklin, 1895); Schömann, _De comitiis Atheniensium_; L. Schmidt, "De
+  Atheniensis reipublicae indole democratica" in _Ind. Lect._ (Marburg,
+  1865); J.W. Headlam, _Election by Lot at Athens_ (Cambridge, 1891).
+  See also the histories of Greece by Meyer, Busolt, Grote, Evelyn
+  Abbott, and J.E. Sandys' edition of the _Constitution of Athens_
+  (1892); for a comparative study, E.A. Freeman, _Comparative Politics_.
+       (J. M. M.)
+
+
+
+
+ECCLESIASTES (Heb. [Hebrew: Kohelet], _Kohelet_, "Koheleth"; Sept.
+[Greek: ekklêsiastês]; Jerome _concionator_), one of the Wisdom Books of
+the Old Testament (see WISDOM LITERATURE). The book, as it stands, is a
+collection of the discourses, observations and aphorisms of a sage
+called Koheleth, a term the precise meaning of which is not certain. The
+Greek _ecclesiastes_ means one who takes part in the deliberations of an
+assembly (_ecclesia_), a debater or speaker in an assembly (Plato,
+_Gorgias_, 452 E), and this is the general sense of the Hebrew word. Its
+form (singular feminine) has been supposed to be the adoption or
+imitation of the Arabic employment of a fem. sing. as the designation of
+a high official person, as is the case in the title _caliph_ (whence the
+rendering in the margin of the Revised Version, "Great orator"); but the
+adoption of an Arabic idiom is not probable. This usage is not Hebrew;
+it is not found either in the Old Testament or in the later (Mishnaic)
+Hebrew. The form may have been suggested by that of the Hebrew word for
+"wisdom." _Koheleth_, however, is employed in the book not as a title of
+wisdom (for "wisdom" is never the speaker), but as the independent name
+of the sage. It is intended to represent him as a member of an assembly
+(_Kahal_)--not the Jewish congregation, but a body of students or
+inquirers, such as is referred to in xii. 9-11, a sort of collegium, of
+which he was the head; and as instructor of this body he gives his
+criticism of life. The author begins, indeed, with identifying his sage
+with King Solomon (i. 12-ii. 11, 12b); but he soon abandons this
+literary device, and speaks in his own name. The rendering "preacher"
+has a misleading connotation.
+
+In the book as we have it there is no orderly exposition of a theory; it
+rather has the appearance of a collection of remarks jotted down by a
+pupil (somewhat after the manner of Xenophon's _Memorabilia_), or of
+extracts from a sage's notebook. It is, however, characterized
+throughout (except in some scribal additions) by a definite thought, and
+pervaded by a definite tone of feeling. The keynote is given in the
+classic phrase with which the discussion opens and with which it closes:
+"Vanity of vanities (i.e. absolute vanity), all[1] is vanity!" Life,
+says the author, has nothing of permanent value to offer. His attitude
+is one not of bitterness but of calm hopelessness, with an occasional
+tinge of disgust or contempt. He fancies that he has tried or observed
+everything in human experience, and his deliberate conclusion is that
+nothing is worth doing. He believes in an all-powerful but indifferent
+God, and is himself an observer of society, standing aloof from its
+passions and ambitions, and interested only in pointing out their
+emptiness.
+
+This general view is set forth in a number of particular observations.
+
+1. His fundamental proposition is that there is a fixed, unchangeable
+order in the world, a reign of inflexible law (i. 4-11, iii. 1-11, 14,
+15, vii. 13, viii. 5-9): natural phenomena, such as sunrise and sunset,
+recur regularly; for everything in human experience a time has been set;
+birth and death, building up and destroying, laughing and weeping,
+silence and speech, love and hate, war and peace, are to be regarded not
+as utterances of a living, self-directing world, but as incidents in the
+work of a vast machine that rolls on for ever; there is an endless
+repetition--nothing is new, nothing is lost; if one thinks he has found
+something new, inquiry shows that it was in existence long ago; God, the
+author of all, seeks out the past in order to make it once more present;
+it is impossible to add to or take from the content of the world,
+impossible to change the nature of things, to effect any radical
+betterment of life; the result is unspeakable weariness--a depressing
+series of sights and sounds. No goal or purpose is discoverable in this
+eternal round; if the sun rises and goes on his journey through the sky,
+it is merely to come back to the place where he rose; rivers flow for
+ever into the sea without filling it. To what end was the world created?
+It is impossible to say. Such is Koheleth's view of life, and it is
+obvious that such a conception of an aimless cosmos is thoroughly
+non-Jewish, if we may judge Jewish thought by the great body of the
+extant literature.
+
+2. Further, says Koheleth, man is impelled to study the world, but under
+the condition that he shall never comprehend it (iii. 11, vii. 23, 24,
+viii. 16, 17). As to the meaning of the Hebrew term _olam_ in iii. 11,
+there are various opinions, but "world" appears to be the rendering
+favoured by the connexion: "God has made everything beautiful in its
+time, and has put the _olam_ into men's minds, yet so that they cannot
+understand His work": the _olam_, the sum of phenomena, is God's work.
+The word is not found in this sense elsewhere in the Old Testament, but
+it so occurs in the Mishna (_Pirke Aboth_, iv. 7), and the vocabulary of
+Ecclesiastes is admittedly similar to that of the Mishna. Only here in
+the Old Testament does it stand as a simple isolated noun; elsewhere it
+is the definition of a noun (in "everlasting covenant," &c.), or it is
+preceded by a preposition, in the phrases "for ever," "of old," or it
+stands alone (sing. or plur.) in the same adverbial sense, "for ever."
+The word means first a remote point in past or future, then a future
+point without limit of time, then a period of history, and finally the
+world considered as a mass of human experiences (cf. [Greek: aiôn]). The
+renderings "eternity" and "future" in the present passage are
+unsatisfactory; the former has an inappropriate metaphysical
+connotation, and yields no distinct sense; the latter does not suit the
+connexion, though there is reference to the future elsewhere (ix. 1).
+God, the text here declares, has made the world an object of man's
+thought, yet so that man can never find out the work that God has done
+(iii. 11). The reference seems to be not so much to the variety and
+complexity of phenomena as to the impossibility of construing them
+rationally or in such a way that man may foresee and provide for his
+future. Man is in the clutches of fate (ix. 11, 12): there is no
+observable relation between exertion and result in life: the race is not
+to the swift nor the battle to the strong; success does not attend
+wisdom, knowledge and skill; men are like fish taken in a net or birds
+caught in a snare.
+
+3. Human life, Koheleth declares, is unsatisfying. He inquired, he says,
+into everything that is done by men under the sun (i. 12-16): God has
+inflicted on men a restless desire for movement and work[2], yet life is
+but a catalogue of fruitless struggles. He gives a number of
+illustrations. In his character of king he tried all the bodily
+pleasures of life (ii. 1-11): he had houses, vineyards, gardens, parks,
+ponds, forests, servants, flocks and herds, treasures of gold and
+silver, singers, wives; all these he set himself to enjoy in a rational
+way--indeed, he found a certain pleasure in carrying out his designs,
+but, when all was done, he surveyed it only to see that it was weary and
+unprofitable. Dropping the rôle of Solomon and speaking as an observer
+of life, the author declares (iv. 4) that the struggle for success is
+the result of rivalry among men, which has no worthy outcome. The
+securing of riches is a fallacious achievement, for often wealth
+perishes by some accident (v. 13 f.), or its possessor is unable to
+enjoy it (vi. 1-3a), or he has no one to whom to leave it, and he cannot
+keep it--naked man comes into the world, naked he goes out. He does not
+consider the possibility of deriving enjoyment from wealth by helping
+the poor or encouraging learning (this latter, indeed, he looks on as
+vanity), and in general he recognizes no obligation on the part of a man
+to his fellows. A noteworthy survival of an old belief is found in vi.
+3: though a man have the great good fortune to live long and to have
+many children, yet, if he have not proper burial the blank darkness of
+an untimely birth is better than he: this latter is merely the negation
+of existence; the former, it appears to be held, is positive misfortune,
+the loss of a desirable place in Sheol, though elsewhere (ix. 5)
+existence in Sheol is represented as the negation of real life. It is
+not necessary to suppose that the writer has here any particular case in
+mind.
+
+If wealth be thus a vain thing, yet a sage might be supposed to find
+satisfaction in wisdom, that is, practical good sense and sagacity; but
+this also the author puts aside as bringing no lasting advantage, since
+a wise man must finally give up the fruit of his wisdom to someone else,
+who may be a fool, and in any case the final result for both fools and
+wise men is the same--both are forgotten (ii. 12-23). A particular
+instance is mentioned (ix. 13-15) of a beleaguered city saved by a wise
+man; but the man happened to be poor, and no one remembered him. The
+whole constitution of society, in fact, seems to the sage a lamentable
+thing: the poor are oppressed, the earth is full of their cries, and
+there is no helper (iv. 1); strange social upheavals may be seen: the
+poor[3] set in high places, the rich cast down, slaves on horseback,
+princes on foot (x. 5-7). He permits himself a sweeping generalization
+(vii. 25-28): human beings as a rule are bad: one may occasionally find
+a good man, never a good woman--woman is a snare and a curse. He (or an
+editor) adds (vii. 29) that this condition of things is due to social
+development: man was created upright (Gen. i. 27; Enoch lxix. 11), but
+in the course of history has introduced corrupting complications into
+life.
+
+4. The natural outcome of these experiences of the author is that he
+cannot recognize a moral government of the world. He finds, like Job,
+that there are good men who die prematurely notwithstanding their
+goodness, and bad men who live long notwithstanding their badness (vii.
+15), though long life, it is assumed, is one of the great blessings of
+man's lot; and in general there is no moral discrimination in the
+fortunes of men (viii. 14, ix. 2).
+
+5. There is no sacredness or dignity in man or in human life: man has no
+pre-eminence over beasts, seeing that he and they have the same final
+fate, die and pass into the dust, and no one knows what becomes of the
+spirit, whether in man's case it goes up to heaven, and in the case of
+beasts goes down into Sheol--death is practically the end-all; and so
+poor a thing is life that the dead are to be considered more fortunate
+than the living, and more to be envied than either class is he who never
+came into existence (iv. 2, 3). It is a special grievance that the
+wicked when they die are buried with pomp and ceremony, while men who
+have acted well are forgotten[4] in the city (viii. 10).
+
+6. That the author does not believe in a happy or active future life
+appears in the passage (iv. 2, 3) quoted above. The old Hebrew view of
+the future excluded from Sheol the common activities of life and also
+the worship of the national god (Isa. xxxviii. 18); he goes even beyond
+this in his conception of the blankness of existence in the underworld.
+The living, he says, at least know that they shall die, but the dead
+know nothing--the memory of them, their love, hate and envy, perishes,
+they have no reward, no part in earthly life (ix. 5, 6); there is
+absolutely no knowledge and no work in Sheol (ix. 10). His conclusion is
+that men should do now with all their might what they have to do; the
+future of man's vital part, the spirit, is wholly uncertain.
+
+7. His conception of God is in accord with these views. God for him is
+the creator and ruler of the world, but hardly more; he is the master of
+a vast machine that grinds out human destinies without sympathy with man
+and without visible regard for what man deems justice--a being to be
+acknowledged as lord, not one to be loved. There can thus be no social
+contact between man and God, no communion of soul, no enthusiasm of
+service. Moral conduct is to be regulated not by divine law (of this
+nothing is said) but by human experience. The author's theism is cold,
+spiritless, without influence on life.
+
+If now the question be asked what purpose or aim a man can have, seeing
+that there is nothing of permanent value in human work, an answer is
+given which recurs, like a refrain, from the beginning to the end of the
+book, and appears to be from the hand of the original author: after
+every description of the vanity of things comes the injunction to enjoy
+such pleasures as may fall to one's lot (ii. 24, 25, iii. 12, 13, 22, v.
+18, 19, viii. 15, ix. 7-10, xi. 7-xii. 7). Elsewhere (ii.), it is true,
+it is said that there is no lasting satisfaction in pleasure; but the
+sage may mean to point out that, though there is no permanent outcome to
+life, it is the part of common-sense to enjoy what one has. The
+opportunity and the power to enjoy are represented as being the gift of
+God; but this statement is not out of accord with the author's general
+position, which is distinctly theistic. All the passages just cited,
+except the last (xi. 7-xii. 7), are simple and plain, but the bearing of
+the last is obscured by interpolations. Obviously the purpose of the
+paragraph is to point out the wisdom of enjoying life in the time of
+youth while the physical powers are fresh and strong, and the impotency
+of old age has not yet crept in. Omitting xi. 8c, 9b, 10b, xii. 1a, the
+passage will read: "Life is pleasant in the bright sunshine--however
+long a man may live, he must be cheerful always, only remembering that
+dark days will come. Let the young man enjoy all the pleasures of youth,
+putting away everything painful, before the time comes when his bodily
+powers decay and he can enjoy nothing." To relieve the apparent
+Epicureanism of this passage, an editor has inserted reminders of the
+vanity of youthful pleasures, and admonitions to remember God and His
+judgment. The author, however, does not recommend dissipation, and does
+not mean to introduce a religious motive--he offers simply a counsel of
+prudence. The exhortation to remember the Creator in the days of youth,
+though it is to be retained in the margin as a pious editorial addition,
+here interrupts the line of thought. In xii. 1a some critics propose to
+substitute for "remember thy Creator" the expression of xi. 9, "let thy
+heart cheer thee"; but the repetition is improbable. Others would read:
+"remember thy cistern" (Bickell), or "thy well" (Haupt), that is, thy
+wife. The wife is so called in Prov. v. 15-19 in an elaborate poetical
+figure (the wife as a source of bodily pleasure), in which the reference
+is clear from the context; but there is no authority, in the Old
+Testament or in other literature of this period, for taking the term as
+a simple prose designation of a wife. Nor would this reference to the
+wife be appropriate in the connexion, since the writer's purpose is
+simply to urge men to enjoy life while they can. The paragraph (and the
+original book) concludes with a sustained and impressive figure, in
+which the failing body of the old man is compared to a house falling
+into decay: first, the bodily organs (xii. 3, 4a): the keepers of the
+house (the arms and hands) tremble, the strong men (the legs and perhaps
+the backbone) are bent, the grinding women (the teeth) cease to work,
+those that look out of the windows (the eyes) are darkened, the
+street-doors are shut, the sound of the mill being low (apparently a
+summary statement of the preceding details: communication with the outer
+world through the senses is cut off, the performance of bodily functions
+being feeble); the rest of v. 4 may refer to the old man's inability to
+make or hear music: in the house there is no sound of birds[5] or of
+singers, there are none of the artistic delights of a well-to-do
+household; further (v. 5a) the inmates of the house fear dangers from
+all powerful things and persons (the old man is afraid of everything),
+the almond tree blossoms (perhaps the hair turns white). The two next
+clauses are obscure.[6] Then comes the end: man goes to his everlasting
+home; the dust (the body) returns to the earth whence it came (Gen. ii.
+7), and the breath of life, breathed by God into the body, returns to
+him who gave it. This last clause does not affirm the immortality of the
+soul; it is simply an explanation of what becomes of the vital principle
+(the "breath of life" of Gen. ii. 7); its positive assertion is not in
+accord with the doubt expressed in iii. 21 ("who knows whether the
+spirit of man goes upward?"), and it seems to be from another hand than
+that of the author of the original book.
+
+There are other sayings in the book that appear to be at variance with
+its fundamental thought. Wisdom is praised in a number of passages (iv.
+13, vii. 5, 11, 12, 19, viii. 1, ix. 16, 17, x. 2, 3), though it is
+elsewhere denounced as worthless. It may be said that the author, while
+denying that wisdom (practical sagacity and level-headedness) can give
+permanent satisfaction, yet admits its practical value in the conduct of
+life. This may be so; but it would be strange if a writer who could say,
+"in much wisdom is much grief," should deliberately laud wisdom. The
+question is not of great importance and may be left undecided. It may be
+added that there are in the book a number of aphorisms about fools (v.
+3[4], vii. 5, 6, x. 1-3, 12-15) quite in the style of the book of
+Proverbs, some of them contrasting the wise man and the fool; these
+appear to be the insertions of an editor. Further, it may be concluded
+with reasonable certainty that the passages that affirm a moral
+government of the world are additions by pious editors who wished to
+bring the book into harmony with the orthodox thought of the time. Such
+assertions as those of ii. 26 (God gives joy to him who pleases him, and
+makes the sinner toil to lay up for the latter), viii. 12 (it shall be
+well with those that fear God, but not with the wicked), xii. 13 f.
+(man's duty is simply to obey the commands of God, for God will bring
+everything into judgment) are irreconcilable with the oft-repeated
+statement that there is no difference in the earthly lots of the
+righteous and the wicked, and no ethical life after death.
+
+Many practical admonitions and homely aphorisms are scattered through
+the book: iv. 5, quiet is a blessing; iv. 9-12, two are better than one;
+iv. 17 (Eng. v. 1), be reverent in visiting the house of God (the temple
+and the connected buildings)--to listen (to the service of song or the
+reading of Scripture) is better than to offer a foolish (thoughtless)
+sacrifice; v. 1 (2), be sparing of words in addressing God; v. 1-5
+(2-6), pay your vows--do not say to the priest's messenger that you made
+a mistake; vii. 2-4, sorrow is better than mirth; vii. 16-18, be not
+over-righteous (over-attentive to details of ritual and convention) or
+over-wicked (flagrantly neglectful of established beliefs and customs);
+here "righteous" and "wicked" appear to be technical terms designating
+two parties in the Jewish world of the 2nd and 1st centuries B.C., the
+observers and the non-observers of the Jewish ritual law; these parties
+represent in a general way the Pharisees and the Sadducees; viii. 2-4,
+x. 20, it is well to obey kings and to be cautious in speaking about
+them, for there are talebearers everywhere; vii. 20, no man is free from
+sin; vii. 21, do not listen to all that you may overhear, lest you hear
+yourself ill spoken of; ix. 4, a living dog is better than a dead lion;
+xi. 1-6, show prudence and decision in business; do not set all your
+goods on one venture; act promptly and hope for the best. At the close
+of the book (xii. 9-12) there are two observations that appear to be
+editorial recommendations and cautions. First, Koheleth is endorsed as
+an industrious, discriminating and instructive writer. Possibly this is
+in reply to objections that had been made to what he had written. There
+follows an obscure passage (v. 11) which seems to be meant as a
+commendation of the teaching of the sages in general: their words are
+said to be like goads (inciting to action) and like nails driven in a
+building (giving firmness to character); they issue from masters of
+assemblies,[7] heads of academies (but not of the Sanhedrin). The
+succeeding clause "they are given from one shepherd" may refer to a
+collection or revision by one authoritative person, but its relevancy is
+not obvious. The "shepherd" cannot be God (Gen. xlix. 24; Ps. xxiii. 1);
+the poetical use of the word would not be appropriate here. The clause
+is possibly a gloss, a comment on the preceding expression. A caution
+against certain books is added (v. 12), probably works then considered
+harmful (perhaps philosophic treatises), of which, however, nothing
+further is known.
+
+_Composition of the Book._--If the analysis given above is correct, the
+book is not a unit; it contains passages mutually contradictory and not
+harmonizable. Various attempts have been made to establish its unity.
+The hypothesis of "two voices" is now generally abandoned; there is no
+indication of a debate, of affirmations and responses. A more plausible
+theory is that the author is an honest thinker, a keen observer and
+critic of life, who sees that the world is full of miseries and unsolved
+problems, regards as futile the attempts of his time to demonstrate an
+ethically active future life, and, recognizing a divine author of all,
+holds that the only wise course for men is to abandon the attempt to get
+full satisfaction out of the struggle for pleasure, riches and wisdom,
+and to content themselves with making the best of what they have. This
+conception of him is largely true, as is pointed out above, but it does
+not harmonize the contradictions of the book, the discrepancies between
+the piety of some passages and the emotional indifference toward God
+shown in others. Other of the Biblical Wisdom books (Job, Proverbs) are
+compilations--why not this? It is not necessary to multiply authors, as
+is done, for example, by Siegfried, who supposes four principal writers
+(a pessimistic philosopher, an Epicurean glossator, a sage who upholds
+the value of wisdom, and an orthodox editor) besides a number of
+annotators; it is sufficient to assume that several conservative scribes
+have made short additions to the original work. Nor is it worth while to
+attempt a logical or symmetrical arrangement of the material. It has
+been surmised (by Bickell) that the sheets of the original codex became
+disarranged and were rearranged incorrectly;[8] by other critics
+portions of the book are transferred hither and thither; in all cases
+the critic is guided in these changes by what he conceives to have been
+the original form of the book. But it is more probable that we have it
+in the form in which it grew up--a series of observations by the
+original author with interspersed editorial remarks; and it is better to
+preserve the existing form as giving a record of the process of growth.
+
+_Date._--As to the date of the book, though there are still differences
+of opinion among scholars, there is a gradual approach to a consensus.
+The Solomonic authorship has long since been given up: the historical
+setting of the work and its atmosphere--the silent assumption of
+monotheism and monogamy, the non-national tone, the attitude towards
+kings and people, the picture of a complicated social life, the strain
+of philosophic reflection--are wholly at variance with what is known of
+the 10th century B.C. and with the Hebrew literature down to the 5th or
+4th century B.C. The introduction of Solomon, the ideal of wisdom, is a
+literary device of the later time, and probably deceived nobody. The
+decisive considerations for the determination of the date are the
+language, the historical background and the thought. The language
+belongs to the post-classical period of Hebrew. The numerous Aramaisms
+point to a time certainly not earlier than the 4th century B.C., and
+probably (though the history of the penetration of Aramaic into Hebrew
+speech is not definitely known) not earlier than the 3rd century. More
+than this, there are many resemblances between the dialect of Koheleth
+and that of Mishna. Not only are new words employed, and old words in
+new significations, but the grammatical structure has a modern
+stamp--some phrases have the appearance of having been translated out of
+Aramaic into Hebrew. By about the beginning of our era the Jews had
+given up Hebrew and wrote in Aramaic; the process of expulsion had been
+going on, doubtless, for some time; but comparison with the later extant
+literature (_Chronicles_, the Hebrew _Ecclesiasticus_ or _Ben-Sira_,
+_Esther_) makes it improbable that such Hebrew as that of Koheleth would
+have been written earlier than the 2nd century B.C. (for details see
+Driver's _Introduction_). The general historical situation, also,
+presupposed or referred to, is that of the period from the year 200 B.C.
+to the beginning of our era; in particular, the familiar references to
+kings as a part of the social system, and to social dislocations
+(servants and princes changing places, x. 7), suggest the troublous time
+of the later Greek and the Maccabean rulers, of which the history of
+Josephus gives a good picture.
+
+The conception of the world and of human life as controlled by natural
+law, a naturalistic cosmos, is alien not only to the prophetic and
+liturgical Hebrew literature but also to Hebrew thought in general.
+Whether borrowed or not, it must be late; and its resemblance to Greek
+ideas suggests Greek influence. The supposition of such influence is
+favoured by some critics (Tyler, Plumptre, Palm, Siegfried, Cheyne in
+his _Jewish Religious Life after the Exile_, and others), rejected by
+some (Zeller, Renan, Kleinert and others). This disagreement comes
+largely from the attempts made to find definitely expressed Greek
+philosophical dogmas in the book; such formulas it has not, but the
+general air of Greek reflection seems unmistakable. The scepticism of
+Koheleth differs from that of Job in quality and scope: it is deliberate
+and calm, not wrung out by personal suffering; and it relates to the
+whole course and constitution of nature, not merely to the injustices of
+fortune. Such a conception has a Greek tinge, and would be found in
+Jewish circles, probably, not before the 2nd century B.C.
+
+A precise indication of date has been sought in certain supposed
+references or allusions to historical facts. The mention of persons who
+do not sacrifice or take oaths (ix. 2) is held by some to point to the
+Essenes; if this be so, it is not chronologically precise, since we have
+not the means of determining the beginning of the movement of thought
+that issued in Essenism. So also the coincidences of thought with
+_Ben-Sira_ (_Ecclesiasticus_) are not decisive: cf. iii. 14 with _B.S._
+xviii. 6; v. 2-6 (3-7) with _B.S._ xxxiv. 1-7; vii. 19 with _B.S._
+xxxvii. 14; x. 8 with _B.S._ xxvii. 26a; xi. 10 with _B.S._ xxx. 21;
+xii. 10, 11 with _B.S._ xxxix. 2 ff., xii. 13 with _B.S._ xliii. 27; if
+there be borrowing in these passages, it is not clear on which side it
+lies; and it is not certain that there is borrowing--the thoughts may
+have been taken independently by the two authors from the same source.
+In any case, since _Ben-Sira_ belongs to about 180 B.C., the date of
+Koheleth, so far as these coincidences indicate it, would not be far
+from 200 B.C. The contrast made in x. 16 f. between a king who is a boy
+and one who is of noble birth may allude to historical persons. The
+antithesis is not exact; we expect either "boy and mature man" or
+"low-born and high-born." The "child" might be Antiochus V. (164 B.C.),
+or Ptolemy V., Epiphanes (204 B.C.), but the reference is too general to
+be decisive. The text of the obscure passage iv. 13-16 is in bad
+condition, and it is only by considerable changes that a clear meaning
+can be got from it. The two personages--the "old and foolish king" and
+the "poor and wise youth"--have been supposed (by Winckler) to be
+Antiochus Epiphanes (175-164 B.C.) and Demetrius (162-150 B.C.), or (by
+Haupt) Antiochus and the impostor Alexander Balas (150-146 B.C.), or (by
+others) Demetrius and Alexander; in favour of Alexander as the "youth"
+it may be said that he was of obscure origin, was at first popular, and
+was later abandoned by his friends. Such identifications, however, do
+not fix the date of the book precisely; the author may have referred to
+events that happened before his time. The reign of Herod, a period of
+despotism and terror, and of strife between Jewish religious parties, is
+preferred by some scholars (Grätz, Cheyne and others) as best answering
+to the social situation depicted in the book, while still others (as
+Renan) decide for the reign of Alexander Jannaeus (104-78 B.C.). The
+data are not numerous and distinct enough to settle the question beyond
+determining general limits: for reasons given above the book can hardly
+have been composed before about 200 B.C., and if, as is probable, a
+Septuagint translation of it was made (though the present Septuagint
+text shows the influence of Aquila), it is to be put earlier than 50
+B.C. Probably also, its different parts are of different dates.
+
+Of the author nothing is known beyond the obvious fact that he was a man
+of wide observation and philosophic thought, of the Sadducean type in
+religion, but non-Jewish in his attitude toward life. He was, doubtless,
+a man of high standing, but neither a king nor a high-priest, certainly
+not the apostate priest Alcimus (1 Macc. vii. ix.); nor was he
+necessarily a physician--there are no details in ch. xii. or elsewhere
+that any man of good intelligence might not know. The book is written in
+prose, some of which is rhythmical, with bits of verse here and there:
+thus i. 2-11 is balanced prose, 12-14 plain prose, 15 a couplet, i.
+16-ii. 25 simple prose, vii. contains a number of poetical aphorisms,
+and so on. Some of the verses are apparently from the author, some from
+editors.
+
+The fortunes of the book are not known in detail, but it is clear that
+its merciless criticism of life and its literary charm made it popular,
+while its scepticism excited the apprehensions of pious conservatives.
+Possibly the _Wisdom of Solomon_ (c. 50 B.C.) was written partly as a
+reply to it. The claim of sacredness made for it was warmly contested by
+some Jewish scholars. In spite of the relief afforded by orthodox
+additions, it was urged that its Epicurean sentiments contradicted the
+Torah and favoured heresy. Finally, by some process of reasoning not
+fully recorded, the difficulties were set aside and the book was
+received into the sacred canon; Jerome (on Eccl. xii. 13, 14) declares
+that the decisive fact was the orthodox statement at the end of the
+book: the one important thing is to fear God and keep His commandments.
+The probability is that the book had received the stamp of popular
+approbation before the end of the 1st century of our era, and the
+leading men did not dare to reject it. It is not certain that it is
+quoted in the New Testament, but it appears to be included in Josephus'
+list of sacred books.
+
+  LITERATURE.--For the older works see Zöckler (in Lange's _Comm._); for
+  Jewish commentaries see Zedner, _Cat. of Heb. books in Libry. of Brit.
+  Mus._ (1867), and for the history of the interpretations, C.D.
+  Ginsburg, _Coheleth_ (1861). _Introductions_ of A. Kuenen, S.R.
+  Driver, Cornhill, König. Articles in Herzog-Hauck, _Realencykl._ (by
+  P. Kleinert); Hastings, _Dict. Bible_ (by A.S. Peake); T.K. Cheyne,
+  _Encycl. Bibl._ (by A.B. Davidson); _Jew. Encycl._ (by D.S.
+  Margoliouth). Commentaries: F. Hitzig (1847); C.D. Ginsburg (1861); H.
+  Grätz (1871); Tyler (1874); Delitzsch (1875); E.H. Plumptre (1881);
+  C.H.H. Wright (1883); Nowack, revision of Hitzig (1883); Volck (in
+  Strack u. Zöckler's _Kurzgef. Komm._, 1889); Wildeboer (in Marti's
+  _Kurzer Hand-Comm._, 1898); C. Siegfried (in W. Nowack's _Handkomm._,
+  1898); Oort (in _De Oude Test._, 1899). Other works: C. Taylor, _Dirge
+  of Koh._ (1874); Wünsche, _Midrash_ on Koh. (in his _Biblioth.
+  rabbin._, 1880); E. Renan, _L'Ecclésiaste_ (1882); Bickell, _Der
+  Prediger_ (1884) and _Kohel.-Untersuchungen_ (1886; Engl. by E.J.
+  Dillon, _Sceptics of Old Test._, 1895); Schiffer, _Das Buch Koh. nach
+  d. Auffass. d. Weisen d. Talmuds_, &c. (1884); A. Palm, _Qoh. u. d.
+  nach-aristotel. Philosophie_ (1885) and _Die Qoh.-Lit._ (1886); E.
+  Pfleiderer, _Die Phil. d. Heraklit_, &c. (1886); Cheyne, _Job and
+  Solomon_ (1887) and _Jew. Relig. Life_, &c. (1898); W. Euringer, _Der
+  Masorahtext d. Koh._ (1890); W.T. Davison, _Wisdom-Lit. of Old Test._
+  (1894); H. Winckler, in his _Altorient. Forschungen_ (1898); J.F.
+  Genung, _Words of Koh._ (Boston, Mass., 1904); P. Haupt,
+  _Ecclesiastes_ (Baltimore, 1905). The rabbinical discussions of the
+  book are mentioned in _Shabbath_, 30b; _Megilla_, 7a; _Eduyoth_, v. 3;
+  _Mishna Yadaim_, iii. 5, iv. 6; _Midrash Koheleth_ (on xi. 9), _Aboth
+  d' Rab. Nathan_, i.     (C. H. T.*)
+
+
+FOOTNOTES:
+
+  [1] The Hebrew has the definite article, "the whole," [Greek: to
+    pan].
+
+  [2] In fact, he suggests, a curse, as in Gen. iii. 17-19, though with
+    a wider sweep than that passage has in mind.
+
+  [3] The text has "folly," but the parallelism and v. 7 point to
+    social, not intellectual, conditions, and a slight change ([Hebrew:
+    haskel] for [Hebrew: misken]) gives the sense "poor."
+
+  [4] The Septuagint has less well: "They (the wicked) are praised in
+    the city."
+
+  [5] The clause is obscure; literally "he (or, one) rises at (?) the
+    voice of the bird," usually understood to refer to the old man's
+    inability to sleep in the morning; but this is not a universal trait
+    of old age, and besides, a reference to affairs in the house is to be
+    expected; the Hebrew construction also is of doubtful correctness. A
+    change of the Hebrew text seems necessary; possibly we should read
+    [Hebrew: ishpal kol], "low is the voice," instead of [Hebrew: yakum
+    lekol] "he rises up at the voice."
+
+  [6] The second is perhaps to be read: "the caper-berry blooms" (white
+    hair); usually "the caper-berry loses its appetizing power"; Eng.
+    Auth. Vers. "desire shall fail." For the meaning of the word _abyona_
+    ("caper-berry," not "desire" or "poverty"), see art. by G.F. Moore in
+    _Journ. of Bibl. Lit._ x. 1 (Boston, Mass., 1891).
+
+  [7] This is the Talmudic understanding of the Hebrew expression
+    (Jerus. Sanhed. 10, 28a, cf. Sanhed. 12a; see Ecclus. xxxix. 2).
+    There is no good authority for the renderings "collectors of maxims,"
+    "collections of maxims."
+
+  [8] It is not certain that the codex form was in use in Palestine or
+    in Egypt as early as the 2nd or the 1st century B.C.
+
+
+
+
+ECCLESIASTICAL COMMISSIONERS, in England, a body corporate, whose full
+title is "Ecclesiastical and Church Estates Commissioners for England,"
+invested with very important powers, under the operation of which
+extensive changes have been made in the distribution of the revenues of
+the Established Church. Their appointment was one of the results of the
+vigorous movements for the reform of public institutions which followed
+the Reform Act of 1832. In 1835 two commissions were appointed "to
+consider the state of the several dioceses of England and Wales, with
+reference to the amount of their revenues and the more equal
+distribution of episcopal duties, and the prevention of the necessity of
+attaching by commendam to bishoprics certain benefices with cure of
+souls; and to consider also the state of the several cathedral and
+collegiate churches in England and Wales, with a view to the suggestion
+of such measures as might render them conducive to the efficiency of the
+established church, and to provide for the best mode of providing for
+the cure of souls, with special reference to the residence of the clergy
+on their respective benefices." And it was enacted by an act of 1835
+that during the existence of the commission the profits of dignities and
+benefices without cure of souls becoming vacant should be paid over to
+the treasurer of Queen Anne's Bounty. In consequence of the
+recommendation of these commissioners, a permanent commission was
+appointed by the Ecclesiastical Commissioners Act 1836 for the purpose
+of preparing and laying before the king in council such schemes as
+should appear to them to be best adapted for carrying into effect the
+alterations suggested in the report of the original commission and
+recited in the act. The new commission was constituted a corporation
+with power to purchase and hold lands for the purposes of the act,
+notwithstanding the statutes of mortmain. The first members of the
+commission were the two archbishops and three bishops, the lord
+chancellor and the principal officers of state, and three laymen named
+in the act.
+
+The constitution of the commission was amended by the Ecclesiastical
+Commissioners Act 1840 and subsequent acts, and now consists of the two
+archbishops, all the bishops, the deans of Canterbury, St Paul's and
+Westminster, the lord chancellor, the lord president of the council, the
+first lord of the treasury, the chancellor of the exchequer, the home
+secretary, the lord chief justice, the master of the rolls, two judges
+of the admiralty division, and certain laymen appointed by the crown and
+by the archbishop of Canterbury. The lay commissioners are required to
+be "members of the Church of England, and to subscribe a declaration to
+that effect." The crown also appoints two laymen as church estates
+commissioners, and the archbishop of Canterbury one. These three are the
+joint treasurers of the commission, and constitute, along with two
+members appointed by the commission, the church estates committee,
+charged with all business relating to the sale, purchase, exchange,
+letting or management of any lands, tithes or hereditaments. The
+commission has power to make inquiries and examine witnesses on oath.
+Five commissioners are a quorum for the transaction of business,
+provided two of them are church estates commissioners; two
+ecclesiastical commissioners at least must be present at any proceeding
+under the common seal, and if only two are present they can demand its
+postponement to a subsequent meeting. The schemes of the commission
+having, after due notice to persons affected thereby, been laid before
+the king in council, may be ratified by orders, specifying the times
+when they shall take effect, and such orders when published in the
+_London Gazette_ have the same force and effect as acts of parliament.
+
+  The recommendations of the commission recited in the act of 1836 are
+  too numerous to be given here. They include an extensive rearrangement
+  of the dioceses, equalization of episcopal income, providing
+  residences, &c. By the act of 1840 the fourth report of the original
+  commissioners, dealing chiefly with cathedral and collegiate churches,
+  was carried into effect, a large number of canonries being suspended,
+  and sinecure benefices and dignities suppressed.
+
+  The emoluments of these suppressed or suspended offices, and the
+  surplus income of the episcopal sees, constitute the fund at the
+  disposal of the commissioners. By an act of 1860, on the avoidance of
+  any bishopric or archbishopric, all the land and emoluments of the
+  see, except the patronage and lands attached to houses of residence,
+  become, by order in council, vested in the commissioners, who may,
+  however, reassign to the see so much of the land as may be sufficient
+  to secure the net annual income named for it by statute or order. All
+  the profits and emoluments of the suspended canonries, &c., pass over
+  to the commissioners, as well as the separate estates of those
+  deaneries and canonries which are not suspended. Out of this fund the
+  expenses of the commission are to be paid, and the residue is to be
+  devoted to increasing the efficiency of the church by the augmentation
+  of the smaller bishoprics and of poor livings, the endowment of new
+  churches, and employment of additional ministers.
+
+  The substitution of one central corporation for the many local and
+  independent corporations of the church, so far at least as the
+  management of property is concerned, was a constitutional change of
+  great importance, and the effect of it undoubtedly was to correct the
+  anomalous distribution of ecclesiastical revenues by equalizing
+  incomes and abolishing sinecures. At the same time it was regarded as
+  having made a serious breach in the legal theory of ecclesiastical
+  property. "The important principle," says Cripps, "on which the
+  inviolability of the church establishment depends, that the church
+  generally possesses no property as a corporation, or which is
+  applicable to general purposes, but that such particular
+  ecclesiastical corporation, whether aggregate or sole, has its
+  property separate, distinct and inalienable, according to the
+  intention of the original endowment, was given up without an effort to
+  defend it" (_Law Relating to the Church and Clergy_, p. 46).
+
+
+
+
+ECCLESIASTICAL JURISDICTION. This phrase in its primary sense imports
+not jurisdiction over ecclesiastics, but jurisdiction exercised by
+ecclesiastics over other ecclesiastics and over the laity.
+"Jurisdiction" is a word borrowed from the jurists which has acquired a
+wide extension in theology, wherein, for example, it is frequently used
+in contradistinction to "order," to express the right to administer
+sacraments as something superadded to the _power_ to celebrate them. So
+it is used to express the territorial or other limits of ecclesiastical,
+executive or legislative authority. Here it is used, in the limited
+sense defined by an American Court, as "the authority by which judicial
+officers take cognizance of and decide causes."
+
+
+  Origin of ecclesiastical jurisdiction.
+
+Such authority in the minds of lay Roman lawyers who first used this
+word "jurisdiction" was essentially temporal in its origin and in its
+sphere. The Christian Church transferred the notion to the spiritual
+domain as part of the general idea of a Kingdom of God correlative, on
+the spiritual side of man upon earth, to the powers, also ordained of
+God, who had dominion over his temporal estate (see CANON LAW). As the
+Church in the earliest ages had executive and legislative power in its
+own spiritual sphere, so also it had "judicial officers," "taking
+cognizance of and deciding causes." Only before its union with the
+State, its power in this direction, as in others, was merely over the
+spirits of men. Coercive temporal authority over their bodies or estates
+could only be given by concession from the temporal prince. Moreover,
+even spiritual authority over members of the Church, i.e. baptized
+persons, could not be exclusively claimed as _of right_ by the Church
+tribunals, if the subject matter of the cause were purely temporal. On
+the other hand, it is clear that _all_ the faithful were subject to
+these courts (when acting within their own sphere), and that, in the
+earliest times, no distinction was made in this respect between clergy
+and laity.
+
+The fundamental principle of ecclesiastical jurisdiction with its
+"sanction" of excommunication will be found in Christ's words in Matt.
+xviii. 15-18. A very early example of criminal spiritual jurisdiction
+exercised by St Paul is found in the case of the incestuous Corinthian
+(1 Cor. v.). We find later the same apostle exercising like jurisdiction
+in the cause of Hymenaeus and Alexander (1 Tim. i. 20). After the time
+of the Apostles, we find this criminal jurisdiction exercised by the
+bishops individually over their respective "subjects"--doubtless with
+the advice of their presbyters according to the precept of St Ignatius
+(c. 110). As neighbouring dioceses coalesced into "provinces" and
+provinces into larger districts (corresponding to the civil "dioceses"
+of the later Roman Empire), the provincial synods of bishops and the
+synods of the larger districts acquired a criminal jurisdiction, still
+purely spiritual, of their own. At first this was "original" and mainly
+(although not exclusively) over bishops (of the province or larger
+district). The beginnings of an appellate jurisdiction in the cases of
+clerics and laymen may be traced before the conversion of the Empire.
+The bishop over whom the synod of neighbouring bishops had exercised
+jurisdiction had no formal right of appeal; but sometimes bishops in
+other parts of the Church would refuse to acknowledge the local
+synodical sentence and would communicate with a bishop whom they deemed
+unjustly deposed. The theory, as expressed in legal phrase by St Cyprian
+in the 3rd century, was that the apostolic power of delegated
+sovereignty from the Lord, alike legislative and judicial, was held in
+joint-tenancy by the whole body of Catholic bishops. In both capacities,
+however, a certain undefined pre-eminence was conceded to the occupants
+of "Apostolic" sees, i.e. sees traditionally founded by Apostles, or of
+sees with a special secular position.
+
+Even before the edict of Milan, at least as early as the latter half of
+the 3rd century, the spiritual sentences of deposition from office had
+sometimes indirect temporal consequences recognized by the secular
+courts. The classical example is the case of Paul of Samosata, bishop of
+Antioch. It would seem that, in the intervals of persecution, some
+rights of property were recognized in the Christian Church and its
+officers; although the Church was an illegal society. After some
+previous abortive trials, Paul of Samosata was deposed and
+excommunicated, in 269, by a great synod of the Antiochene district.
+Paul, notwithstanding his deposition, kept possession of the episcopal
+residence. The local church sought recovery of it before the tribunals
+of the Empire. The judicial authorities requested a rescript from the
+emperor Aurelian for the decision of the cause. Aurelian referred the
+matter to the bishop of Rome and the bishops of Italy, who gave their
+award in favour of the Antiochene Church.
+
+
+  Temporal Jurisdiction of the Church.
+
+Side by side with this which we may call criminal jurisdiction--none the
+less real or coercive because its sanctions were purely spiritual--there
+grew up a quasi-jurisdiction in causes entirely temporal, based upon the
+free consent of the parties to accept the arbitration of the bishop.
+This system had also its roots in the New Testament (see Matt, xviii.
+15-17 and 1 Cor. vi. 1-8). In the matter of criminal jurisdiction we
+paused for a moment at the edict of Milan; but we may at once trace this
+second or civil branch of episcopal judicature or quasi-judicature down
+as far as the reign of Charlemagne, when it underwent a fundamental
+change, and became, if _either_ litigant once chose, no longer a matter
+of consent but of right.
+
+Constantine decreed that judgment in causes might be passed by bishops
+when litigants preferred their adjudication to that of the secular
+courts (see his epistle to the Numidian bishops and _Cod. Theodos. Tit.
+de Episcopis_). The episcopal judgment was to be equivalent to that of
+the emperor and irreversible, and the civil authorities were to see to
+its execution. Saints Ambrose and Augustine both spent days in deciding
+temporal causes. Honorius, in the West, at the end of the 4th century,
+made a constitution providing that if any desired to litigate before the
+bishops they should not be forbidden, but that in civil matters the
+prelates should render judgment in the manner of arbitrators by consent
+(_Cod._ 1, _Tit._ iv.). Where the faithful had had recourse to the
+bishop, no appeal was to be allowed, and the judges were to command
+execution of the episcopal decree. A quarter of a century later,
+however, Valentinian III. in the West expressly provided that bishops
+were not to be permitted to be judges (that is, of course, in temporal
+causes), save by the consent of the parties. This legislation was,
+substantially, adopted by Justinian.
+
+On the revival of the Western Empire, however, Charlemagne, in the
+beginning of the 9th century, under the mistaken belief that he was
+following the authority of Constantine I. and Theodosius I., took a
+great step forward, by which the bishop ceased to be a mere legally
+indicated arbitrator by consent in secular causes, and became a real
+judge. By a capitulary he provided that either litigant, without the
+consent of the other party, and not only at the beginning of a suit but
+at any time during its continuance, might take the cause from lay
+cognizance and transfer it to the bishop's tribunal. He re-enacted the
+prohibition of appeal.
+
+It should be remembered that, from the latter part of the 3rd century,
+the leading bishops had generally been trained in secular learning. St
+Cyprian, St Ambrose and St Augustine, St Paulinus of Nola and St John
+Chrysostom had practised law as teachers or advocates. St Ambrose and St
+Paulinus had even held high administrative and judicial offices.
+
+
+  Roman empire from Constantine.
+
+To return to the evolution of ecclesiastical jurisdiction from the time
+of Constantine. With the "Nicene period" came a great development on the
+criminal side. A system begins to be formed, and the secular arm
+supports the decrees of the Church. The first trace of system is in the
+limited right of appeal given by the first oecumenical council of Nicaea
+and its provision that episcopal sentences or those of provincial synods
+on appeal were to be recognized throughout the world. The fifth canon
+provides that those, whether clerics or laymen, who are cut off from
+communion in any particular province are not to be admitted thereto
+elsewhere. Still examination must be had whether persons have been
+expelled from the congregation by any episcopal small-mindedness
+([Greek: mikropsychia]), or contentious spirit, or such-like harshness
+([Greek: aêdia]). That this may be conveniently inquired into, synods
+are to be held, three in every year, in each province, and questions of
+this kind examined. There is to be no "stay of execution"; the episcopal
+sentence is to prevail until the provincial synod otherwise decide. It
+will be noticed that as yet no provision is made for appeals by
+_bishops_ from provincial synods sitting in first instance.
+
+The edicts of Milan had only admitted the Christian Church among the
+number of lawful religions; but the tendency (except in the time of
+Julian) was towards making it the only lawful religion. Hence the
+practice, immediately after Nicaea I., of superadding banishment by the
+emperor to synodical condemnation. The dogmatic decrees of Nicaea I.
+were at once enforced in this temporal manner. On the other hand, the
+Arian reaction at court worked its objects (see Pusey, _Councils of the
+Church_) by using the criminal spiritual jurisdiction of synods against
+the Catholics--often packing the synods for the purpose. The acts of
+councils of this age are full of the trials of bishops not only for
+heresy but for immorality and common law crimes. The accusations are
+frequently unfounded; but the trials are already conducted in a certain
+regular forensic form. The secular authorities follow the precedent of
+Nicaea I. and intervene to supplement the spiritual sentence by
+administrative penalties. Sometimes an imperial officer of high rank
+(as, e.g. a "count") is present at the synod, as an assessor to maintain
+order and advise upon points of procedure. Leading examples may be found
+in the various prosecutions of St Athanasius, in whose case also there
+is the germ of an appeal, _tanquam ab abusu_. It has been contended
+that, according to later and more formulated jurisprudence, such an
+appeal would have lain, since the trial at Tyre was not concerned with
+purely spiritual matters (see the case in Hefele, _Councils_, in loc.).
+
+The trial of St Athanasius led to extensions of the right of appeal.
+This was favoured by the development of the greater sees into positions
+of great administrative dignity, shortly to be called "patriarchal." A
+synod was held at Rome, attended by bishops from various regions, which
+reversed the original judgment of the synod of Tyre which had condemned
+Athanasius. A much larger synod at Antioch, gathered only from the East,
+on the other hand, confirmed that judgment. This last synod did
+something to systematize the criminal procedure of the Church, and its
+legislation has been always received.
+
+This legislation marks another step forward. Deposition of a bishop by a
+synod, or of a priest or deacon by his bishop, is to take effect even
+pending an appeal, and a cleric continuing his functions after sentence
+in first instance is to lose all right of appeal. The appeal given by
+Nicaea I. to clerics and laymen from episcopal excommunications is
+extended. The synod may restore them if convinced of the justice of
+their cause (and not merely in cases of [Greek: aêdia]). A bishop may
+appeal to a great assembly of bishops. Any bishop, priest or deacon
+"importuning" the emperor, instead of exerting his right of appeal to
+synods, is to lose all right of appeal and never to be restored or
+pardoned. If a provincial synod be divided as to the guilt of a bishop,
+the metropolitan is to convene bishops from the neighbouring provinces
+to decide the cause jointly with the bishops of the original province.
+
+A few years later, in 347, the council of Sardica, a council of
+practically the whole West save Africa, reversed Tyre and acquitted St
+Athanasius after a full judicial inquiry. This council endeavoured to
+set up a system of appeals in the case of bishops, in which the see of
+Rome was made to play a great part. "Out of honour to the memory of St
+Peter," a condemned bishop may ask the intervention of Rome. If this be
+done, the synod of first instance is to send letters to Julius, bishop
+of Rome. If that prelate think the cause should be heard again, he is to
+appoint judges; if otherwise, the original judgment is to be confirmed.
+Pending appeal, the appellant's see is not to be filled up. The judges
+appointed by the bishop of Rome to hear the appeal are to be from the
+neighbouring provinces. The appellant may, however, request that bishop
+to send priests from his side to sit with the synod of appeal. If such
+priests are sent, they are to preside in the court of appeal. These
+canons were always repudiated in the East, and when, sixty years
+afterwards, they were, for the first time, heard of in Africa, they were
+repudiated there also.
+
+A rescript of Gratian in 378 empowered the bishop of Rome to judge
+bishops with the assistance of six or seven other bishops or, in the
+case of a metropolitan, of fifteen comprovincial bishops. A bishop
+refusing to come to Rome was to be brought there by the civil power. The
+rescript, however, was not incorporated in the Codes and perhaps was
+only a temporary measure.
+
+The tendency to give pre-eminence to Rome appears again in an imperial
+letter to St Flavian, who, in the judgment of the East, was bishop of
+Antioch, but who was rejected by the West and Egypt, summoning him to
+Rome to be there judged by the bishops of the imperial city--a summons
+which St Flavian did not obey (Tillemont, _Mém. Ecc._). In Africa in the
+beginning of the 5th century Apiarius, a priest who had been deposed by
+the bishop of Sicca for immorality, and whose deposition had been
+affirmed by the "provincial synod," instead of further appealing to a
+general synod of Africa, carried his appeal to Pope Zosimus. The pope
+received the appeal, absolved him and restored him to the rank of
+priest, and sent a bishop and two priests as legates to Africa with
+instructions to them to hear the cause of Apiarius anew and for
+execution of their sentence to crave the prefect's aid; moreover, they
+were to summon the bishop of Sicca to Rome and to excommunicate him,
+unless he should amend those things which the legates deemed wrong. The
+upshot of a long conflict was that the papal claim to entertain appeals
+from Africa by priests and deacons was rejected by the African bishops,
+who in their final synodical epistle also repudiate in terms any right
+of appeal by African _bishops_ to "parts beyond the seas" (see Hefele,
+_Councils_, bk. viii.).
+
+The story of the administrative development of the Church in the 5th
+century is mainly the story of the final emergence and constitution of
+the great "patriarchates," as authorities superior to metropolitans and
+provincial synods. In consequence of the occupants of the thrones of
+Constantinople and Alexandria falling successively into opposite
+heresies, the question arose how "patriarchs" were to be judged. In both
+cases, as it seems, an attempt was made by the bishop of Rome to depose
+the erring patriarch by his authority as primate of Christendom, acting
+in concert with a Western synod. In both cases, apparently, an
+oecumenical synod ignored the Roman deposition and judged the alleged
+offences of the respective patriarchs in first and last instance. The
+third and fourth oecumenical synods (Ephesus, 431; Chalcedon, 451) were
+primarily tribunals for the trials of Nestorius and Dioscorus; it was
+secondarily that they became organs of the universal episcopate for the
+definition of the faith, or legislative assemblies for the enactment of
+canons. Nothing is more remarkable than their minute care as to
+observance of rules of procedure. In both cases, imperial assessors were
+appointed. At Ephesus the Count Candidian was commissioned to maintain
+order, but took little part in the proceedings. At Chalcedon, on the
+other hand, the imperial commissioners decided points of order, kept the
+synod to the question, took the votes and adjourned the court. But the
+synod alone judged and pronounced sentence. No oecumenical synod has
+tried a patriarch of Old Rome while yet in the flesh. The fifth
+oecumenical council came nearest to so doing, in the case of Vigilius.
+That pope, although in Constantinople, refused to attend the sittings of
+the council. He was cited three times, in the canonical manner, and upon
+not appearing was threatened in the third session with anathema (Hefele,
+_Councils_, sect. 268 _ad fin._). He was not, however, charged with
+direct heresy, as were Nestorius and Dioscorus, and the synod seems to
+have hesitated to deal stringently with the primate of Christendom. In
+the seventh session it accepted the suggestion of Justinian, merely to
+order the name of Vigilius to be removed from the liturgical prayers, at
+the same time expressing its desire to maintain unity with the see of
+Old Rome (Hefele, sect. 273). After the council, Justinian banished the
+pope to Egypt, and afterwards to an island, until he accepted the
+council, which he ultimately did (ib. 276). The sixth oecumenical synod
+decreed that the dead pope Honorius should be "cast out from the holy
+Catholic Church of God" and anathematized, a sentence approved by the
+reigning pope Leo II. and affirmed by the seventh oecumenical synod in
+787.
+
+The constitution of the patriarchal system resulted in the recognition
+of a certain right of appeal to Rome from the larger part of the West.
+Britain remained outside that jurisdiction, the Celtic churches of the
+British islands, after those islands were abandoned by the Empire,
+pursuing a course of their own. In the East, Constantinople, from its
+principality, acquired special administrative pre-eminence, naturally
+followed, as in the case of "old Rome," by judicial pre-eminence. An
+example of this is found in the ninth canon of Chalcedon, which also
+illustrates the enforcement upon a clerical plaintiff in dispute with a
+brother cleric of that recourse to the arbitration of their
+ecclesiastical superior already mentioned. The canon provides that any
+clerk having a complaint against another clerk must not pass by his own
+bishop and turn to secular tribunals, but first lay bare his cause
+before him, so that by the sentence of the bishop himself the dispute
+may be settled by arbitrators acceptable to both parties. Any one acting
+against these provisions shall be subject to canonical penalties. If any
+clerk have a complaint against his own bishop, he shall have his cause
+adjudicated upon by the synod of the province. But if a bishop or clerk
+have a difference with the metropolitan of his province let him bring it
+before the exarch of the "diocese" (i.e. the larger district answering
+to the civil "diocese"), or before the royal see of Constantinople, who
+shall do justice upon it. An "exarch" means properly a superior
+metropolitan having several provinces under him. In the next century
+Justinian (_Nov._ 123, c. 22) put the other patriarchates on the same
+footing as Constantinople. In c. 21 he gives either plaintiff or
+defendant an appeal within ten days to the secular judge of the locality
+from the bishop's judgment. If there be no appeal, that judge is to give
+execution to the episcopal award. The growth of a special "original"
+jurisdiction at Constantinople, which perhaps developed earlier than
+the corresponding institution at Rome, may be traced to the fact that
+bishops from all parts were constantly in Constantinople. The bishop of
+Constantinople, even before he became properly "patriarch," would often
+assemble a synod from these visiting bishops, which acquired the
+technical name of [Greek: synodos endêmousa], the synod of sojourners.
+This synod frequently decided questions belonging to other
+patriarchates.
+
+The criminal jurisdiction thus exercised was generally speaking
+unlimited. It must be remembered that the _forum externum_ of the
+ecclesiastical jurisdiction, in the sense in which we now use the
+phrase, of a judge deciding causes, was not then clearly marked off from
+the _forum internum_, or what afterwards came to be called the "tribunal
+of penance" (see Van Espen, _Jus ecc. univ._ pars iii. tit. iv. c. 1).
+Ecclesiastical proceedings by way of prosecution are called "criminal,"
+but they are primarily _pro salute animae_; whereas temporal criminal
+proceedings are primarily for the protection of the state and its
+citizens. Hence a Christian might be first punished in the civil courts
+and then put to public penance by the ecclesiastical jurisdiction, or
+vice versa: an apparently double system of punishment which the medieval
+Church, when the _forum externum_ had become quite separated from the
+_forum internum_, sometimes repudiated (see Maitland, _English Canon
+Law_, 138, 139, 144).
+
+Theodosius began the system of giving secular authority to Church
+tribunals. Thus, in 376, L. 23 _Cod. Theodos. de. Episcopis_, &c.,
+subjected clerics for small offences pertaining to the observances of
+religion to bishops and synods. In 399, L. 1 _Cod. de Religione_
+provides that, when it is a matter of religion, it beseems the bishop to
+judge. A rescript of Constantius, in 355, inserted in _Cod. Theod._
+lxii. _de Epis. Ecc. et Cler._, excluded bishops from accusations before
+secular judges and commanded such accusations to be speedily brought
+before the tribunal of other bishops. This law was probably only
+intended to be of a temporary character. Then comes the law of Gratian
+already noticed. Then, in 399, a law of Honorius (_Cod. Theod._ L. 1 _de
+Religione_): "As often as it concerns religion, it is meet that the
+bishops should judge, but other causes which belong to ordinary
+jurisdiction or to public law are to be heard in the ordinary courts
+(_legibus oportet audiri_)." L. 3 _de Epis. Jud._, at the end of the
+Theodosian Code, seems spurious (see the comment of Gothofredus in
+loco). But a constitution of Honorius in 412 (_Cod. Theod._ L. xli. _de
+Epis. Ecc. et Cler._) provides that clerks are not to be accused except
+before the bishop. Bishops, priests, deacons, and every other "minister
+of the Christian law" of inferior degree, are taken from secular
+jurisdiction in criminal cases. The words are quite general; but it has
+been contended that they apply only to crimes of an ecclesiastical
+character (see Gothofredus in loc.; Van Espen, pars iii. tit. iii. c. 1,
+10). In 425 a constitution of Theodosius II. provides that a recent
+decree of the usurper John should be disregarded and that clerks whom he
+had brought before secular judges should be reserved for the episcopal
+jurisdictions, "since it is not lawful to subject the ministers of the
+divine office to the arbitrament of temporal powers." Justinian has a
+clearer perception of the demarcation between the spheres of spiritual
+and temporal law. The 83rd Novell provides that if the offence be
+ecclesiastical, needing ecclesiastical correction, the bishop shall take
+cognizance of it. The 123rd Novell (c. 21) provides that if a clerk be
+accused of a secular crime he shall be accused before his bishop, who
+may depose him from his office and order, and then the competent judge
+may take him and deal with him according to the laws. If the prosecutor
+have first brought him before the civil judge, the evidence is to be
+sent to the bishop, and the latter, if he thinks the crime has been
+committed, may deprive him of his office and order, and the judge shall
+apply to him the proper legal punishment. But if the bishop think the
+evidence insufficient, the affair shall be referred to the emperor, by
+way of appeal both from bishop and judge. If the cause be
+ecclesiastical, the civil judges are to take no part in the inquiry. The
+law includes with clerics, monks, deaconesses, nuns, ascetics; and the
+word "clerics" covered persons in minor orders, down to doorkeepers. It
+will be noticed that Justinian supposes that the prosecutor may begin
+the proceedings before the civil judge. A constitution of Alexius
+Comnenus I. seems to send him to the special forum of the accused.
+
+
+  Anglo-Saxon courts.
+
+Certain enactments of later Saxon times in England have been sometimes
+spoken of as though they united together the temporal and spiritual
+jurisdictions into one mixed tribunal deriving its authority from the
+State. In the latter part of the 10th century, laws of Edgar provided
+that the bishop should be at the county court and also the alderman, and
+that there each of them should put in use both God's laws and the
+world's law (Johnson's _English Canons_, i. 411). This probably was, as
+Johnson suggests, that the bishop might enforce secular laws by
+ecclesiastical censure and the alderman ecclesiastical laws with secular
+punishment. But the two jurisdictions were kept separate; for by another
+law of Edgar (_Leges Edg._ c. v.) it was provided that "in the most
+august assembly the bishop and alderman should be present, and the one
+should interpret to the people the law of God, the other the laws of
+men." Edgar, in a speech to St Dunstan and the bishops in synod (in
+969), said, "I hold in my hands the sword of Constantine, you that of
+Peter. Let us join right hands and unite sword to sword" (Hardouin,
+_Conc._ tom. vi. p. 1, col. 675). The juxtaposition of the judicatures
+may, however, have led to some confusion between them.
+
+As to appeals the mixed council of Cliff at Hoo (747) said they should
+go to the synod of the province. The only appeal to Rome in Saxon times
+was that of St Wilfrid, bishop of York, who appealed from the division
+of his see and his deposition for refusing to consent to it, and was
+heard in a Roman synod under the presidency of Pope Agatho. The synod
+found him unlawfully deposed and ordered his restoration. Upon his
+return to England, the Roman judgment was refused recognition and he was
+for a time imprisoned. Ten years later he was recalled to York, but
+refusing to consent to the division of his see was again deposed and
+again appealed to Rome. The appeal was heard at great length, in a synod
+of 703 under John VI., deputies from the archbishop of Canterbury being
+present. St Wilfrid was justified and was sent back to his see, with
+papal letters to the kings of Northumbria and Mercia. The Roman decree
+was again disregarded. At the council of "Nid" he was reconciled to the
+other bishops of the province, but not restored. In the end he was
+brought back to York, but not to the undivided see. The details of the
+case will be found in Wilkins, _Concilia_, in Mansi, _Concilia_, under
+the various councils named, and in Haddan & Stubbs, _Councils and Eccl.
+Documents_, vol. iii.
+
+
+  Penalties inflicted by ecclesiastical courts.
+
+The penalties which the spiritual court could inflict, in the period
+between the edict of Milan and c. 854, were properly excommunication
+whether generally or as exclusion from the sacraments for a term of
+months or years or till the day of death and (in the case of clerics)
+suspension or deposition. Gradually, however, doubtless by way of
+commutation of excommunication and of penance, temporal penalties were
+added, as scourging, banishment, seclusion in a monastery, fines. It is
+difficult to say how far some of these temporal penalties were
+penitential only or how far they could be inflicted _in invitos_. But
+the secular arm, from the time of Nicaea I., was in the habit of aiding
+spiritual decrees, as by banishing deposed bishops, and gradually by
+other ways, even with laymen. Scourging (although it had been a
+well-known punishment of the synagogue) was at first forbidden. Can. 28
+(26) of the Apostolic Canons imposes deposition on any bishop, priest or
+deacon striking the delinquent faithful. In Africa, however, a contrary
+practice early sprang up (see St Augustine, _Epist._ clix. _ad Marcellum
+al._ cxxxiii.). The small council of Vannes in Brittany in 465 made it
+an alternative punishment for clerks convicted of drunkenness (Can. 13).
+Canon 13 of the first council of Orleans, which has been cited in this
+matter, seems to have no application. St Gregory the Great seems to
+assume that scourging and seclusion in a monastery are in the discretion
+of episcopal tribunals (see _Epistles_, lib. ii. ep. 11, 40, 42, 44, 45;
+lib. vii. ep. 11, 67; lib. xii. ep. 31, c. 4). The 16th council of
+Toledo (in 693) has been cited as if it visited certain very great
+sinners with scourging as an ecclesiastical punishment. In fact, it only
+approves the punishment as ordered by the Visigothic laws. An alleged
+decree of a council of Autun in 670 is part of a code of discipline for
+monasteries (see authorities cited by Hefele, _Councils_, sect. 290,
+towards the end). Banishment does not seem to have been inflicted by the
+spiritual court _in invitum_. Seclusion in a monastery seems first to
+have been used by the civil power in aid of the spiritual. The fifth
+canon of the council of Macon, in 584, forbids clergy to dress like
+laymen and imposes a penalty of thirty days' imprisonment on bread and
+water; but this may be merely penitential. There is little evidence of
+the imposition of fines as ecclesiastical penalties; but there are
+references to the practice in the epistles of St Gregory the Great,
+notably in his instructions to St Augustine. Gregory III. copies from St
+Gregory I. Probably these also were by way of penance. Isolated examples
+in the early middle ages of metropolitans dealing with their suffragan
+bishops by imprisonment in chains were extra-canonical abuses, connected
+with the perversion of Church law which treated the metropolitan (who
+originally was merely convener of the provincial synod and its
+representative during the intervals of sessions) as the feudal "lord" of
+his comprovincials.
+
+With the later 9th century we enter upon a new epoch, and by the time of
+Gregory VII., in the 11th century, the tribunals have fallen into the
+hands of a regular class of canonists who are in fact professional
+church-lawyers in orders. The changes due to the adoption of the False
+Decretals by Nicholas I. and the application of their principles by
+Hildebrand (afterwards Gregory VII.) are discussed in the article CANON
+LAW. The later medieval system, thus inaugurated, may be considered (1)
+in its hierarchy, (2) in the subject matter of its jurisdiction, (3) in
+its penalties.
+
+
+  Later medieval system.
+
+1. (a) It is a system of courts. Much that had been done by bishops,
+_sine strepitu forensi et figura judicii_, is now done in the course of
+regular judicial procedure. Again, the court takes the place of the
+synod. The diocesan synod ceases to have judicial work. The court of the
+metropolitan takes the place of the provincial synod, except possibly
+for the trial of bishops, and even this becomes doubtful.
+
+(b) At first the bishop was the only judge in the diocesan court and he
+always remains a judge. But just as the king appoints judges to hear
+_placita coram rege ipso_, and the feudal lord appoints his seneschal or
+steward, so the bishop appoints his official.
+
+(c) The archdeacon acquires a concurrent ordinary jurisdiction with the
+bishop (see ARCHDEACON). For some time it was considered that he was a
+mere office-holder dependent on the will of the bishop with a
+jurisdiction merely "vicarial"; but by the 13th century it was settled
+that he held a "benefice" and that his jurisdiction over causes was
+ordinary and independent of the bishop (Van Espen, pars i. tit. xii. c.
+1; Fournier, _Les Officialités au moyen âge_, p. 134). It was partly in
+order to counterpoise the power of archdeacons that bishops created
+officials (Fournier, p. 8). Archdeacons in course of time created
+officials who presided in court in their stead. The extent of
+jurisdiction of archdeacons depended much upon local customs. In England
+the custom was generally in their favour. Ordinarily, the appeal from an
+archdeacon or his official lay to the court of the bishop; but by custom
+the appeal might be to the court of the metropolitan: The Constitutions
+of Clarendon, in 1164, made the appeal from the court of the archdeacon
+lie to the court of the bishop.
+
+(d) The official of the bishop might be his official principal, who was
+his _alter ego_, or a special officer for a particular locality
+(_officialis foraneus_). The latter was treated as a mere delegate, from
+whom an appeal could be made to the bishop. The former had one
+consistory with the bishop, so that appeals from him had to be made to
+the court of the metropolitan. How far the official principal had
+jurisdiction in criminal matters by virtue of his office, how far it was
+usual to add this jurisdiction by special commission, and what were the
+respective limits of his office and that of the vicar-general, are
+questions of some nicety. The emphasis in Italy was on the vicar-general
+(_Sext. de officio Vicarii_). In the Low Countries, France and England
+the jurisdiction of the official principal was wider (Van Espen, pars
+i. tit. xii. cc. 4, 5; Fournier, p. 21). But he could not try criminal
+matters unless specially committed to him (Lyndwood, _Provinciale_, lib.
+ii. tit. 1). Later in England it became usual to appoint one man to the
+two offices and to call him chancellor, a word perhaps borrowed from
+cathedral chapters, and not in use for a diocesan officer till the time
+of Henry VIII. or later (see CHANCELLOR). In Ireland the title, till the
+church was disestablished, was vicar-general.
+
+The importance of distinguishing the normal functions of an official
+principal and a vicar-general lies in this: that it was gradually
+established that as a king should not hear causes but commit them to his
+judges, so a bishop should not hear causes but appoint an official to
+hear them (see Ridley, _View of the Civil and Eccl. Law_; Ayliffe,
+_Parergon juris ecclesiastici_, p. 161; Godolphin, _Abridgement of the
+Laws Ecclesiastical_, p. 8). The "parlements" of France were constantly
+insisting on the independence and irremovability of the official
+(Fournier, p. 219). But jurisdiction which was not necessarily incident
+to the office of the official principal, that is to say voluntary
+jurisdiction, such as the granting of licences and institution to
+benefices, and criminal jurisdiction over clerks (and probably over
+laymen), the bishop could reserve to himself. Reservations of this
+nature are made in many English patents of chancellors and were held
+good in _R._ v. _Tristram_, 1902, 1 K.B. 816.
+
+(e) The ecclesiastical and temporal courts are kept distinct. The
+charter of William the Conqueror abrogated the laws of Edgar. No bishop
+or archdeacon "shall any longer hold pleas in the Hundred concerning
+episcopal law nor draw a cause which concerns the rule of such to the
+judgment of men of the world" (Stubbs, _Select Charters_, part iii.). In
+France, where the bishop was a temporal baron, his feudal and his
+spiritual courts were kept by distinct officers (Fournier, p. 2).
+
+(f) From the bishop, or his official, appeal lay to the metropolitan,
+who again could hear causes by his official. The Constitutions of
+Clarendon recognize this appeal (c. viii.).
+
+(g) An appeal lay from the court of the metropolitan to that of the
+primate. There were many disputes as to the existence of these primates
+(see Maitland, _Canon Law in the Church of England_, p. 121). In England
+the dispute between Canterbury and York was settled by making them both
+primates, giving Canterbury the further honour of being primate of all
+England. In France the primatial sees and the course of appeals to them
+were well established (Fournier, p. 219).
+
+(h) Several attempts were made by metropolitans and their officials to
+take causes arising in the dioceses of their comprovincials in the first
+instance and not by way of appeal. The officials of primates in their
+turn made similar attempts. After long struggles this was hindered, in
+France by the bull _Romana_ (Fournier, p. 218), in England by the Bill
+of Citations, 23 Henry VIII. c. 9, and Canon 94 of the Canons of 1603.
+The preamble of the "Bill of Citations" is eloquent as to the mischief
+which it is framed to prevent. There are, however, a few cases in which
+the metropolitan is still allowed to cite in the first instance. One of
+them was in cases of "perplexity." "Perplexity" arose where the
+suffragans "could not owing to the geographical limitations of their
+competence do full justice" (Maitland, pp. 118-119). Such was the case
+of probate where notable goods of the deceased lay in more than one
+diocese. Hence the origin of the "prerogative court" of Canterbury (cf.
+Van Espen, pars i. tit. xix.; and for Spain, Covarruvias, _Pract.
+Quaest._ c. 9).
+
+(i) Gradually there grew up a mass of peculiar and exempt jurisdictions
+(Ayliffe, pp. 417, 418; Phillimore, Eccl. Law, pp. 214, 927; de
+Maillane, _Dict. du droit canonique_, s.v. "Exemptions"). Exempt
+jurisdictions began with the monasteries and were matter of vehement
+discussion in the later middle ages. There were no true exemptions
+before the 11th century (Van Espen, pars iii. tit. xii.). Peculiar or
+special jurisdiction, equal to that of the bishop, was given to deans
+and chapters over the cathedral precincts and in places where they had
+corporate property (see _Parham_ v. _Templer_, 3 Phil. Ecc. R. 22).
+Sometimes it was given to deans alone or to prebendaries in the parishes
+whence they derived their prebends. Where the archdeacon had a
+jurisdiction co-ordinate with the bishop, it was called a peculiar. The
+metropolitans had peculiars within the dioceses of their comprovincials
+wherever they had residences or manors, and some whose origin is
+uncertain, e.g. that of the fifteen parishes in the deanery of the
+Arches. The official administering justice for the metropolitan was
+usually called a dean. From a peculiar jurisdiction ranking as episcopal
+the appeal lay to the court of the metropolitan. As to metropolitan
+peculiars, the metropolitan might give an appeal from the dean to his
+regular official principal. Thus, in Canterbury there was an appeal from
+the dean of Arches to the official principal of the Arches court. When
+peculiars were abolished (_vide infra_) the dean of Arches disappeared,
+and his title, in the 19th century, was erroneously given to the
+official principal. On peculiars in Spain cf. Covarruvias, _Works_, tit.
+i. p. 410. The French parlements, after the middle ages, discouraged
+them. In exempt convents the head of the monastery or priory exercised
+jurisdiction subject to an appeal to the pope.
+
+(j) It is said that originally a metropolitan had only one official
+principal, who, like the metropolitan himself, acted both for the
+diocese and province. Fournier (p. 219) says that in France it was not
+till the 17th century that there grew up a custom of having different
+officials for the metropolitan, one for him as bishop, a second as
+metropolitan, and even a third as primate, with an appeal from one to
+the other, and that it was an abuse due to the parlements which strove
+to make the official independent of the bishop. In England there has
+been, for a long time, a separate diocesan court of Canterbury held
+before the "commissary." The word is significant as showing that there
+was something special and restricted about the position. In York there
+are two courts, one called the consistory for the diocese, the other
+called the chancery for the province. But the same person was often
+official of both courts.
+
+(k) In England the Constitutions of Clarendon added a provision for
+appeal to the king, "and if the archbishop shall have failed in doing
+justice recourse is to be had in the last resort (_postremo_) to our
+lord the king, that by his writ the controversy may be ended in the
+court of the archbishop; because there must be no further process
+without the assent of our lord the king." The last words were an attempt
+to limit further appeal to Rome. It will be observed that the king does
+not hear the cause or adjudicate upon it. He merely corrects slackness
+or lack of doing justice (_Si archiepiscopus defecerit in justitia
+exhibenda_) and by his writ (_precepto_) directs the controversy to be
+determined in the metropolitan's court. As bishop Stubbs says (_Report
+of Eccl. Comm._ vol. i. _Hist. App._ i.): "The appeal to the king is
+merely a provision for a rehearing before the archbishop, such failure
+to do justice being not so much applicable to an unfair decision as to
+the delays or refusal to proceed common at that time" (cf. Joyce, _The
+Sword and the Keys_, 2nd ed. pp. 19-20). The _recursus ad principem_, in
+some form or other of appeal or application to the sovereign or his lay
+judges, was at the end of the middle ages well known over western
+Europe. This recourse in England sometimes took the form of the appeal
+to the king given by the Constitutions of Clarendon, just mentioned, and
+later by the acts of Henry VIII.; sometimes that of suing for writs of
+_prohibition_ or _mandamus_, which were granted by the king's judges,
+either to restrain excess of jurisdiction, or to compel the spiritual
+judge to exercise jurisdiction in cases where it seemed to the temporal
+court that he was failing in his duty. The _appellatio tanquam ab abusu_
+(_appel comme d'abus_) in France was an application of a like nature.
+Such an appeal lay even in cases where there was a refusal to exercise
+voluntary jurisdiction (de Maillane, _Dictionnaire du droit canonique_,
+tit. "Abus," cf. tit. "Appel"). This writer traces their origin to the
+14th century; but the procedure does not seem to have become regularized
+or common till the reigns of Louis XII. or Francis I. (cf. _Dict.
+eccl._, Paris, 1765, titt. "Abus" and "Appel comme d'abus"). On the
+_recursus ad principem_ and the practice of "cassation" in Belgium,
+Germany and Spain, cf. Van Espen's treatise under this title (_Works_,
+vol. iv.) and _Jus eccles. univ._ pars iii. tit. x. c. 4. Louis XIV.
+forbad the parlements to give judgment themselves in causes upon an
+_appel comme d'abus_. They had to declare the proceedings null and
+abusive and command the court Christian to render right judgment (Edict
+of 1695, arts. 34, 36, cited in Gaudry, _Traité de la législation des
+cultes_, Paris, 1854, tom. i. pp. 368, 369).
+
+In Catalonia "Pragmatics," letters from the prince, issued to restrain
+jurisdiction assumed by ecclesiastical judges contrary to the customs of
+the principality. Thus in 1368 Peter III. evoked to the royal court a
+prosecution for abduction pending before the archbishop of Tarragona,
+declaring that the archbishop and the official were incompetent to judge
+noblemen. See this and other instances collected in _Usages y demas
+derechos de Cataluña_, by Vives y Cebriá (Barcelona, 1835), tom. iv. p.
+137 et seq.
+
+(l) Lastly there was the appeal to the patriarchs, i.e. in the West to
+Rome. The distinguishing feature of this appeal was that the rule of the
+other appeals did not apply to it. In the regular course of those
+appeals an appellant could not leap the intermediate stages; but he
+could at any stage go to this final appeal, _omisso medio_, as it was
+technically called (see _de appell. c. Dilect._ iii. for general rule,
+and c. 3 _de appell._ in 6 for different rule in case of the pope, and
+authorities cited in Van Espen, pars iii, tit. x. c. 2, 5). Van Espen
+says: "The whole right of appeal to the Roman pontiff _omisso medio_ had
+undoubtedly its origin in this principle, that the Roman pontiff is
+ordinary of ordinaries, or, in other words, has immediate episcopal
+authority in all particular churches, and this principle had its own
+beginning from the False Decretals."
+
+Appeals to Rome lay from interlocutory as well as final judgments.
+Causes could even be evoked to Rome before any judgment and there heard
+in first instance (Van Espen, pars iii. tit. x. c. 1, 8).
+
+There was an alleged original jurisdiction of the pope, which he
+exercised sometimes by permanent legates, whom Gregory VII. and his
+successors established in the chief countries of Europe, and to whom
+were committed the legislative executive and judicial powers of the
+spiritual "prince" in the districts assigned to them. These Clement IV.
+likened to "pro-consuls" and declared to have "ordinary" jurisdiction;
+because they had jurisdiction over every kind of cause, without any
+special delegation, in a certain defined area or province (c. ii. _de
+Officio Legati_ in 6). They were expressed to have not merely appellate
+but original jurisdiction over causes (iii. c. i. _de Officio Legati_).
+The occupants of certain sees by a kind of prescription became legates
+without special appointment, _legati nati_, as in the case of
+Canterbury. In the 13th century Archbishop Peckham, says Maitland (p.
+117), as archbishop "asserted for himself and his official (1) a general
+right to entertain in the first instance complaints made against his
+suffragans' subjects, and (2) a general right to hear appeals _omisso
+medio_." It was, for the time, determined that the archbishop might
+himself, in virtue of his legatine authority, entertain complaints from
+other dioceses in first instance, but that this legatine jurisdiction
+was not included in the ordinary jurisdiction of his official principal,
+even if the archbishop had so willed it in his commission. In fact,
+however, the official did before the end of the later medieval period
+get the same power as the archbishop (Maitland, pp. 118-120; cf.
+Lyndwood, lib. v. tit. 1), till it was taken from him by the Bill of
+Citations.
+
+After legates came special delegates appointed by the pope to hear a
+particular cause. It was the general practice to appoint two or three to
+sit together (Van Espen, pars iii. tit. v. c. 2, 37). These might
+sub-delegate the whole cause or any part of it as they pleased, ibid.
+9-18. Dr Maitland (essay on "The Universal Ordinary") thinks, but
+without very much foundation, that great numbers especially of the more
+important causes were tried before these delegates; although the records
+have largely perished, since they were the records of courts which were
+dissolved as soon as their single cause had been decided. These courts
+were convenient, since it was the custom to appoint delegates resident
+in the neighbourhood, and the power of sub-delegation, general or
+limited, simplified questions of distance. In Belgium causes appealed
+to Rome had to be committed to local delegates (Van Espen, pars iii.
+tit. v. c. 3, tit. x. c. 2).
+
+There could be an appeal from these delegates to the pope and from the
+pope himself to the pope "better informed" (Van Espen, pars iii. tit. x.
+c. 2, 12, 13). So personal had the system of jurisdiction become that
+even the trials of bishops ceased to be necessarily conciliar. Generally
+they were reserved to the pope (Van Espen, pars iii. tit. iii. c. 5,
+17-19); but in England the archbishop, either in synod, or with some of
+his comprovincial bishops concurring, tried and deposed bishops (see
+case of Bishop Peacock and the other cases cited in _Read_ v. _Bishop of
+Lincoln_, 14 P.D. 148, and Phillimore, _Eccl. Law_, pp. 66 et seq.).
+
+(m) The jurisdiction of a bishop _sede vacante_ passed, by general law,
+to the dean and chapter; but in England the metropolitans became
+"guardians" of the spiritualities and exercised original jurisdiction
+through the vacant diocese (Phillimore, pp. 62-63), except in the case
+of Durham, and with a peculiar arrangement as to Lincoln.
+
+If the metropolitan see were vacant the jurisdiction was exercised by
+the dean and chapter through an official (Rothery, _Return of Cases
+before Delegates_, Nos. 4, 5). As to France see Fournier, p. 294.
+
+(n) Officials, even of bishops and metropolitans, need not be in holy
+orders, though Bishop Stubbs in his paper in the _Report of the
+Commission on Ecclesiastical Courts_ seems to say so. They had to be
+clerics, that is, to have received the tonsure. Even papal delegates
+might be simple clerks (Van Espen, pars iii. tit. v. c. 2, 20).
+
+It came, however, to be the practice to impose some restrictions, as on
+clerks twice married. Thus Archbishop Chichele provided that no clerk
+married or bigamous (that is, having had two wives in succession) should
+exercise spiritual jurisdiction (see Lyndwood, lib. iii. tit. 3). Abroad
+unsuccessful attempts were made by local councils to enact that
+officials and vicars-general should be in holy orders (Hefele on
+Councils of Tortosa in 1429 and Sixth of Milan in 1582). These councils,
+as will be seen, are late.
+
+(o) With or without the concurrence and goodwill of the national Church,
+restrictions were imposed by the State on the papal jurisdiction,
+whether original or appellate. In England the Constitutions of Clarendon
+(by chap. viii.) prohibited appeals to the pope; but after the murder of
+St Thomas of Canterbury Henry II. had to promise not to enforce them.
+The statutes 38 Edw. III. st. 2, 13 Rich. II. st. 2, c. 2, and 16 Rich.
+II. c. 5 forbid such appeals; but it is suggested that notwithstanding
+the generality of their language they refer only to cases of temporal
+cognizance. Cases upon the execution of these statutes are collected in
+Stillingfleet, _On Ecclesiastical Jurisdiction_, p. 189; Gibson,
+_Codex_, 83. Obstacles were placed in the way of appeals to the pope
+_omisso medio_. Thus when a writ of _significavit_ issued on the mandate
+of a bishop, an appeal to Rome availed not to stay execution; but if
+there were an appeal to the archbishop it was otherwise. It therefore
+became the custom to lodge a double appeal: one to the archbishop "for
+defence," and the other to the pope as the real appeal ("Hostiensis,"
+_Super Decret._ ii. fol. 169; cf. Owen, _Institutes of Canon Law_, 1884,
+pt. i. c. 19, 5).
+
+There seems to have been no machinery for assisting the original or
+appellate jurisdiction of the pope by secular process,--by
+_significavit_ or otherwise.
+
+The matrimonial cause between Henry VIII. and Catharine of Aragon was
+the most famous English cause tried by delegates under the "original"
+jurisdiction of the pope, and was ultimately "evoked" to Rome. The
+foreseen adverse termination of this long-drawn cause led to Henry's
+legislation.
+
+When the temporal courts interfered to prevent excess of jurisdiction,
+they did so by prohibiting the ecclesiastical court from trying and the
+suitor from suing in that court. The pope could not be effectively
+prohibited, and no instance is recorded of a prohibition to papal
+delegates. But suitors have been prohibited from appealing to the pope
+(see per Willes, J., in _Mayor of London_ v. _Cox_, L.R. 2 H.L. 280).
+Whatever may have been the law, it is certain that, notwithstanding the
+statutes of Edw. III. and Rich. II., appeals to Rome and original trials
+by papal delegates did go on, perhaps with the king's licence; for the
+statute 24 Hen. VIII. c. 12 recites that the hearing of appeals was an
+usurpation by the pope and a grievous abuse, and proceeds to take away
+the appeal in matrimonial, testamentary and tithe causes, and to hinder
+by forbidding citation and process from Rome, all original hearings
+also. The statute 25 Hen. VIII. c. 19 follows this up by taking away
+appeals in all other subjects of ecclesiastical jurisdiction.
+
+In 1438 the council of Basel took away all papal original jurisdiction
+(save in certain reserved cases--of which _infra_), evocation of causes
+to Rome, appeals to Rome _omisso medio_, and appeals to Rome altogether
+in many causes. Such appeals when permissible, except the "greater,"
+were to be tried by delegates on the spot (31st Session; Mansi,
+_Concilia, in loco_). These proceedings at Basel were regarded at Rome
+as of no effect. Nevertheless this decree and others were adopted by a
+French national council at Bourges and promulgated by the king as a
+"Pragmatic Sanction" (Migne, _Dict. du droit canonique_, "Pragmatique
+Sanction"). The parlements registered the Sanction and the effect was
+permanent in France. Louis XI. and Charles VIII. sought to revoke it;
+but both parlements and states-general refused to recognize the revoking
+decrees. In 1499 Louis XII. ordered the Pragmatic to be inviolably
+observed. The parlements thereupon condemned several private persons for
+obtaining bulls from Rome. In 1516 a Concordat between Leo X. and
+Francis I. settled all these questions in the sense of the Pragmatic,
+substantially according to the Basel canon. All causes, except the
+"greater," were to be terminated in the country where the proper
+cognizance would lie (Migne, op. cit. "Concordat"). By this Concordat,
+by an ordinance of Francis I. in 1539, by two or three other royal
+edicts, and (above all) by the practice of the parlements, explanatory
+of this legislation, and their _arrêts_, the conflict of secular and
+ecclesiastical jurisdictions was settled until the Revolution (Migne,
+_ubi sup._). "Greater causes" came in France to be restricted to
+criminal prosecutions of bishops. Even in these the original
+jurisdiction of the pope was taken away. In first instance they were
+tried by the provincial synod. Thence there was appeal to the pope (de
+Maillane, op. cit. s.v. "Causes majeures"; _Dict. eccl._, Paris, 1765,
+s.v. "Cause"). The only original jurisdiction left to the pope was in
+the case of the matrimonial causes of princes. But they could only be
+heard on the spot by judges delegate. Examples are the causes of Louis
+XII. and Jeanne of France in 1498, and of Henry IV. and Marguerite of
+Valois in 1599 (Migne, op. cit. s.v. "Causes"). The prohibition of papal
+interference was enforced if necessary by the _appel comme d'abus_
+(_vide supra_). Out of respect for the pope this appeal was not brought
+against his decrees but against their execution (_Dict. eccl._, Paris,
+1765, s.v. "Abus").
+
+Spain appears to have permitted and recognized appeals to the pope. A
+royal writ of the 16th century cited by Covarruvias (c. xxxv.) prohibits
+execution of the sentence of a Spanish court Christian pending an appeal
+to the pope.
+
+
+  Civil jurisdiction.
+
+2. The subject matter over which the ecclesiastical courts had
+jurisdiction was no longer purely "criminal" with a civil
+quasi-jurisdiction by way of arbitration. In the later middle ages these
+courts had jurisdiction over most questions, except indeed the then most
+important ones, those relating to real property. This civil jurisdiction
+was sometimes concurrent with that of the secular courts, sometimes
+exclusive. For England it may be thus classified:--
+
+(a) _Matrimonial._--This arose naturally from the sacred character of
+Christian marriage. This jurisdiction was exclusive. From it followed
+the right of the courts Christian to pronounce upon questions of
+legitimacy. Upon this right an inroad was early made, in consequence of
+the question of legitimation by subsequent marriage. In the 12th century
+the Church's rule, that subsequent marriage did legitimize previous
+issue, was settled (c. 6, x. 4, 17). The king's judges then began to ask
+the ordinary the specific question whether A. B. was born before or
+after his parents' marriage. After the inconclusive proceedings at the
+realm-council of Merton (1236), when spiritual and temporal lords took
+opposite views, the king's judges went a step further and thenceforward
+submitted this particular question to a jury. All other questions of
+legitimacy arising in the king's courts were still sent for trial to the
+bishop and concluded by his certificate (see Pollock and Maitland,
+_Hist. Eng. Law before Edward I._ vol. i. 105-106; Maitland, _ubi
+supra_, pp. 53-56).
+
+(b) _Testamentary and in regard to succession from intestates._--Real
+property was not the subject of will or testament in the medieval
+period. But as to personal property, the jurisdiction of the courts
+Christian became exclusive in England. The Church, East and West, had
+long asserted a right to supervise those legacies which were devoted to
+pious uses, a right recognized by Justinian (_Cod._ i. 3. 46). The
+bishop or, failing him, the metropolitan, was to see such legacies
+properly paid and applied and might appoint persons to administer the
+funds (Pollock and Maitland, op. cit. ii. 330). This right and duty
+became a jurisdiction in all testamentary causes. Intestacy was regarded
+with the greatest horror, because of the danger to the intestate's soul
+from a death without a fitting part given to pious uses (Maine, _Ancient
+Law_, ed. 1906, note by Pollock, p. 230; cf. Pollock and Maitland, op.
+cit. ii. 354). Hence came the jurisdiction of the ordinary in intestacy,
+for the peace of the soul of the departed. This head of ecclesiastical
+jurisdiction was in England not transferred to the secular court till
+1857.
+
+(c) _Church Lands._--If undoubtedly held in _frankalmoign_ or "free
+alms," by a "spiritual" tenure only, the claim of jurisdiction for the
+ecclesiastical _forum_ seems to have been at first conceded. But the
+Constitutions of Clarendon (c. 9) reserved the preliminary question, of
+"frankalmoign" or not, for a jury in the king's court. Then, if the
+tenure were found free alms, the plea was to be heard in the court
+Christian. From the 13th century, however, inclusive, the king's courts
+insisted on their exclusive jurisdiction in regard to all realty,
+temporal or "spiritual" (Pollock and Maitland, op. cit. i. 106).
+
+(d) _Title to present to and possession of benefices._--As to the title
+to present to benefices, the courts Christian at one time had concurrent
+jurisdiction with the temporal courts. "Advowsons" were, however, looked
+upon as a species of "real" property in England, and therefore the
+king's court early claimed exclusive jurisdiction in disputes where the
+title to present was involved. The Constitutions of Clarendon provided
+that these causes should be heard only in the king's court (c. 1). This
+rule was applied even where both litigants were "spiritual." In the 13th
+century abbots sue each other in the royal court for advowsons (Selden
+Soc. _Select Civil Pleas_, i. pl. 245). In 1231, in such a suit, the
+bishop of London accepts wager of battle (Pollock and Maitland, op. cit.
+i. 105). In cases, however, where the title to present was not in
+question, but the fitness of the clerk presented, or, in cases of
+election to benefices, the validity of the election, there was
+jurisdiction in the courts Christian.
+
+(e) _The recovery of tithes and church dues,_ including in England
+church rates levied to repair or improve churches and churchyards.
+
+(f) Questions concerning _fabrics, ornaments, ritual and ceremonial_ of
+churches.
+
+(g) _Administration of pious gifts and revenues given to prelates or
+convents._--Their right application could be effectively enforced only
+in the courts Christian; until the rise in England of the equitable
+jurisdiction of the court of chancery and the development of the
+doctrine of "uses" at the end of the middle ages.
+
+(h) _Enforcement of contractual promises made by oath or pledge of
+faith._--The breaking of such a promissory oath was called "perjury" (as
+in classical Latin and in Shakespeare), contrary to modern usage which
+confines the word to false evidence before a court of justice. In regard
+to the execution of these promises, the jurisdiction of the
+ecclesiastical courts was possibly traversed by c. 15 of the
+Constitutions of Clarendon; but allowed by the statute 13 Edw. I. st. 4.
+As just intimated, besides the enforcement of the promise, the
+"perjury" was treated as an ecclesiastical crime.
+
+The _criminal jurisdiction of courts Christian over laymen_ included,
+besides these "perjuries," (a) all _sexual offences_ not punishable on
+indictment; (b) _Defamation of character_ (the king's courts came in
+time to limit this to such defamation as could not be made the subject
+of a temporal action); (c) _Offences by laymen against clerks_ (i.e.
+against all "tonsured" persons, supra); (d) _Offences in regard to holy
+places_--"brawling" and such like; (e) _Heresy, schism, apostasy,
+witchcraft_.
+
+In regard to "clerks," there was (1) all the criminal jurisdiction which
+existed over laymen, and (2) criminal jurisdiction in regard to
+professional misconduct. Concerning "felonious" clerks the great
+questions discussed were whether the courts Christian had exclusive
+jurisdiction or the king's court, or whether there was a concurrent
+jurisdiction. The subject was dealt with in the Constitutions of
+Clarendon, formally revoked after the murder of St Thomas of Canterbury.
+In the 13th century it was recognized that a "clerk" for felony was
+subject only to ecclesiastical trial and punishment; punishment which
+might involve lifelong imprisonment. For "misdemeanours," as yet
+unimportant, he had no exemption from secular jurisdiction (Pollock and
+Maitland, op. cit. ch. iv.). At some indeterminate later period, the
+"clerk" was tried for felony by a jury in the king's court and then
+"pleaded his clergy," after conviction there, and was remitted to the
+ordinary for ecclesiastical punishment. "Clerks" for the purpose of
+"benefit of clergy" included not only persons in minor orders, but all
+"religious" persons, i.e. monks, friars, nuns, &c. Later the custom
+arose of taking "clerk" to include any "literate," even if not in orders
+or "religious" (cf. Stephen, _Hist. Crim. Law_, i. 461). The statute 4
+Hen. VII. c. 13 took away benefit of clergy, if claimed a second time,
+from persons not "within orders," in certain bad cases. 4 Hen. VIII. c.
+2 (a temporary act) took away "clergy," in certain heinous crimes, from
+all persons not in "holy" orders. This statute was partly renewed by 22
+Hen. VIII. c. 13. Other changes were introduced by 23 Hen. VIII. c. 1
+and later acts. In time, "benefit of clergy" became entirely diverted
+from its original objects.
+
+In _France_, till 1329, there seems to have been no clear line of
+demarcation between secular and ecclesiastical jurisdictions. Beaumanoir
+(_Coutume de Baulvoisis_, ch. xi., cited Gaudry, op. cit. i. 22) had
+laid down the principle that spiritual justice should meddle only with
+spiritual things. In the year named the secular courts complained to the
+king, Philip of Valois, of the encroachments of the courts Christian.
+The "cause" was solemnly argued before that monarch, who decided to
+leave things as they were (Migne, _Dict. du droit canon._, s.v.
+"Officialités"). In 1371 Charles V. forbade spiritual courts to take
+cognizance of "real" and "possessory" actions even in regard to clerks
+(Migne, loc. cit.; cf. Gaudry, _ubi sup._). From this period the
+parlements began the procedure which, after the Pragmatic Sanction of
+Charles VII., in 1438 took regular shape as the _appel comme d' abus_
+(_supra_; Migne, loc. cit.). Testamentary causes at first were subject
+to the concurrent jurisdiction of the spiritual and secular courts.
+After the 14th century, the latter had exclusive jurisdiction (Van
+Espen, op. cit. lib. iii. tit. ii. cc. 2, 15, 16). In regard to
+_marriage_ the secular jurists distinguished between the civil contract
+and the sacrament, for purposes of separating the jurisdiction (_Dict.
+eccl._, Paris, 1765, s.v. "Mariage"). The voluntary jurisdiction as
+regards dispensations was kept for the Church. The contentious
+jurisdiction of the courts Christian was confined to promises of
+marriage, nullity of marriage caused by "diriment" impediments only,
+validity or invalidity of the sacrament, divorce _a thoro_ (ibid.).
+Questions in regard to the _property in a benefice_ were for the courts
+Christian; in regard to its _possession_, for the king's courts. But if
+a "possessory" action had been brought in the latter, a subsequent suit
+in the courts spiritual for the property was deemed "abusive" and
+restrained (ib., s.v. "Pétitoire") _Breach of faith or of promise
+confirmed by oath_ was matter for the court Christian (Fournier, pp. 95,
+99, 109, 125). This branch of jurisdiction was larger and more freely
+used than in England (cf. Pollock and Maitland, op. cit., as to
+Normandy). The only other remaining civil jurisdiction of the
+ecclesiastical courts was in _personal actions where clerks were
+defendants_ (Migne, op. cit., s.v. "Officialités," Fournier, pp.
+65-125); or, after the 14th century, where both parties were clerks. In
+regard to crimes delicts (_délits_) were divided into classes for
+purposes of jurisdiction. Clerks were punishable only in the court
+Christian, except in cases of grave crimes such as murder, mutilation
+(Fournier, p. 72), and cases called "royal cases" (_vide infra_). Laymen
+were punishable in the court Christian for the _délits_ following:
+injury to sacred or religious places, sacrilege, heresy (except where it
+was a "royal case"), sorcery, magic, blasphemy (also punishable in the
+secular court), adultery, simony, usury and infractions of the truce of
+God (Fournier, pp. 90-93). What were called "privileged delicts" were
+judged in the case of the clergy conjointly by the spiritual judge and
+the king's judge. Bishops had no exemption (_Dict. ecc._, s.v. "Délits,"
+"Cas privilégié," "Causes majeures"). "Royal cases" included such crimes
+as touched the prince, as all forms of treason; or the dignity of his
+officers; or the public safety. In this class were also included such
+heresies as troubled the state, as by forbidden assemblies, or by
+teaching prohibited doctrine. Among these heresies were reckoned
+idolatry, atheism, Protestantism, relapse (_ib. et_ "Cas royaux,"
+"Hérésie"). These were of exclusive royal jurisdiction as against both
+spiritual courts and the courts of feudal lords. A similar claim was
+made by Pombal for Portugal (_vide infra_).
+
+The parlements, in order to have a ready means of enforcing all these
+restrictions by _appel comme d'abus_, compelled the bishops to appoint
+officials, Frenchmen, graduates, and (as it seems) "seculars" (_Dict.
+eccl._, Paris, 1765, s.v. "Official"). This last qualification was
+disputed (see Fevret, _Traité de l'abus_).
+
+3. _Punishments._--Ecclesiastical sanctions were divided into
+_punishments_ (_poenae_), either purely temporal in character or else of
+a mixed spiritual and temporal character, and _censures_ (_censurae_),
+purely spiritual and remedial (see Van Espen, pars iii. tit. xl. cc. 1,
+3; Phillimore, _Ecclesiastical Law_, p. 1064). In the book last cited
+_censurae_ and _poenae_ are classed together as "censures" (which is the
+modern use).
+
+_Poenae._--(a) Fines sprang from the older custom of directing alms by
+way of penance in the internal forum (Van Espen, _ubi sup._ c. 1, 5-10).
+They were to be applied to pious uses. (b) _Reclusion in a monastery_
+continued from former period, and might be either temporary or perpetual
+(loc. cit. 17-19). (c) _Imprisonment_, in the bishop's prison, might be
+in chains, or on bread and water, and temporary or perpetual. In its
+severer forms it was only inflicted for more atrocious crimes which the
+secular law would have punished with death (loc. cit. 21-27). The act 23
+Henry VIII. c. 11 made special provision for convicted clerks who broke
+out of the prisons of the ordinary. (d) _Fustigation_, as in former
+period, was hardly an ecclesiastical punishment. If given, it was to be
+of a paternal character (loc. cit. 39-45). Punishments of a mixed nature
+were: (e) _Suspension_ either from office alone or from office and
+benefice; (f) _Deprivation_ of benefice; (g) _Deposition_ or
+_Degradation_ (a more solemn and ceremonial form) from the ministry; (h)
+_Irregularity_--not always a punishment--a state of incapacity to be
+ordained, or, being ordained, to execute the ministry; this might result
+from some defect of mind and body, but was also incurred by some grave
+offences.
+
+_Censures_ were as follows: (i) _Suspension_ from attending divine
+offices or _ab ingressu ecclesiae_, more appropriate for a layman. A
+clerk in like case might be suspended from office. (j) _Interdict_ was
+another form of partial or total suspension from the benefit of the
+rites and sacraments of the Church. An interdict might be personal or
+local (see INTERDICT). (k) _Excommunication_ was either greater or less.
+The greater separated entirely from the Church. It might be pronounced
+under anathema. The less deprived of participation in the sacraments,
+and made a clerk incapable of taking a benefice.
+
+On the European continent the courts Christian often carried out their
+decrees by their own apparitors who could levy pecuniary penalties on a
+defendant's goods (Van Espen, pars iii. tit. ix. c. 4). They could
+arrest and imprison. In England, except in the peculiar case of
+imprisonment pending trial for heresy, or in the case of a clerk
+convicted of crime, these things could not be. The sentence of the court
+Christian had in all other cases to be enforced by the secular arm.
+Early in Henry II.'s time it had become the custom of England for the
+court Christian to "signify" its sentence of excommunication to the king
+and to demand from him a writ of _significavit_ to the sheriff, to
+imprison the person excommunicated. The writ apparently issued for no
+court inferior to the bishop's, unless upon the bishop's request. In
+some sense the king's writ of _significavit_ was discretionary; but its
+issue could be enforced by excommunication or interdict.
+
+In the cases of heresy, apostasy and sorcery, the spiritual courts
+sought the aid of the secular jurisdiction to superadd the punishment of
+death. Incorrigible offenders on these matters were "left" to the
+secular power, to be corrected with due "animadversion." This provision
+of the fourth Lateran Council in 1215 was always interpreted to mean
+death (see Van Espen, _Observ. in Conc. Lat. IV. Canones_, and the
+decree in the _Sext. ut inquisitionis negotium_; and, as to English law
+and practice, Maitland, op. cit., Essay vi., and pp. 161, 176; 2 Hen.
+IV. c. 15; Fitzherbert, _Natura brevium_, 269; 2 Hen. V. st. 1, c. 7).
+The "capital" punishment was generally (always in England) by burning.
+Burning was an English punishment for some secular offences.
+
+The Concordat with Francis I. by which the pope gave up the right of
+hearing appeals from France was not many years before the legislation of
+Henry VIII. in England. Both monarchs proceeded on the same lines; but
+Francis I. got the pope's consent: Henry VIII. acted _in invitum_, and
+in time went rather further.
+
+
+  Ecclesiastical jurisdiction in England.
+
+The Statute of Appeals (24 Hen. VIII. c. 12) takes away appeals to Rome
+in causes testamentary and matrimonial and in regard to right of tithes,
+oblations and obventions. A final appeal is given to the archbishop of
+the particular province; but in causes touching the king a final appeal
+is given to the Upper House of Convocation of the province. The statute
+is aimed at appeals; but the words used in it concerning "citations and
+all other processes" are wide enough to take away also the "original"
+jurisdiction of the pope. No appeal was yet given to the crown.
+Canterbury, York, Armagh, Dublin, Cashel and Tuam are put in the place
+of Rome. The English and Irish provinces are treated as self-contained.
+All ends there.
+
+The "Act of Submission of the Clergy" (25 Hen. VIII. c. 19) took away
+_all_ appeals to Rome and gave a further appeal, "for lack of justice,"
+from the several courts of the archbishops to the king in chancery.
+Thence a commission was to issue to persons named therein to determine
+the appeal definitely. This was copied from the then existent practice
+in admiralty appeals and was the origin of the so-called court of
+delegates. It is a moot question whether this statute took away the
+appeal to the Upper Houses of the various convocations in causes wherein
+the king was concerned (see _Gorham_ v. _Bishop of Exeter_, 15 Q.B. 52;
+_Ex parte Bishop of Exeter_, 10 C.B. 102; _Re Gorham_ v. _Bishop of
+Exeter_, 5 Exch. 630). 37 Hen. VIII. c. 17 provided that married laymen
+might be judges of the courts Christian if they were doctors of civil
+law, created in any university. This qualification even was considered
+unnecessary in Charles I.'s time (_Cro. Car._ 258). Canon 127 of 1603
+provided that the judges must be learned in the civil and ecclesiastical
+laws and at least masters of arts or bachelors of laws. Canon Law as a
+study had been practically prohibited at the universities since 1536
+(Merriman, _Thomas Cromwell_, i. 142-143; _Cal. State Papers_, vol. ix.
+p. xxix. 117; Owen, _Institutes of Canon Law_, viii.). The substitution
+of "civilians," rather than common lawyers, for canonists (civilians,
+hitherto, not an important body in England) had important consequences
+(see Maitland, op. cit. 92 et seq.).
+
+Henry VIII. had exercised his jurisdiction as Supreme Head through a
+vicar-general. Edward VI. exercised original jurisdiction in spiritual
+causes by delegated commissions (see Archdeacon Hale, _Precedents in
+Criminal Cases_, p. xlviii.). Unless the king was to be regarded as an
+ecclesiastical person, they were not properly ecclesiastical courts;
+although spiritual persons might sit in them, for they sat only as royal
+commissioners. The same point has been taken by large bodies of clergy
+and laity in regard to the court of final appeal created by 25 Hen.
+VIII. c. 19 and its present successor the judicial committee of Privy
+Council (_infra: Rep. Com. Ecc. Discipline_, pp. 9, 94 et seq.). At any
+rate the "original" jurisdiction claimed for the monarch personally and
+his delegates, under Henry VIII. and Edward VI., has not permanently
+remained. In theory, Hooker's contentions have been conceded that "kings
+cannot in their own proper persons decide questions about matters of
+faith and Christian religion" and that "they have not ordinary spiritual
+power" (_Ecc. Pol._ vii. 8, 1, 6; cf. _XXXIX. Articles_, Art. 37).
+
+Under Henry VIII. a system began of making certain crimes, which
+previously had been only of spiritual cognizance, felonies (25 Hen.
+VIII. c. 6), excluding thereby spiritual jurisdiction (Stephen, _Hist.
+Crim. Law_, ii. 429). Bigamy (in its modern sense) was thus made felony
+(1 Jac. I. c. 11). In this reign and the next, temporal courts were
+sometimes given jurisdiction over purely spiritual offences. A trace of
+this remains in 1 Edw. VI. c. 1 (still on the statute book; Stephen,
+_Hist. Crim. Law_, ii. 439). Other traces occur in the Acts of
+Uniformity, which make offences of depraving the Book of Common Prayer
+triable at Assizes (between 23 Eliz. c. 1 and 7 & 8 Vict. c. 102--also
+at Sessions) as well as in the courts Christian.
+
+During Edward VI.'s time the courts Christian seem practically to have
+ceased to exercise criminal jurisdiction (Hale, _Precedents in Criminal
+Cases_, p. xlix.). But they sat again for this purpose under Mary and
+Elizabeth and (save between 1640 and 1661) continued regular criminal
+sessions till towards the end of the 17th century as continuously and
+constantly as the king's courts (op. cit.).
+
+The "ordinary" ecclesiastical tribunals of the later middle ages still
+subsist in England, at least as regards the laity. This is hardly the
+case elsewhere in the Western Church, though some exceptions are noted
+below. Nevertheless, their exercise of criminal jurisdiction over the
+laity is now in practice suspended; although in law it subsists (see
+Stephen, _Hist. Crim. Law_; _Ray_ v. _Sherwood_, 1 Curt. R. 193; 1 Moore
+P.C.R. 363; the observations of Kelly, C.B., in _Mordaunt_ v.
+_Moncrieffe_, L.R. 2 Sc. & Div. 381, and of Lord Coleridge in _Martin_
+v. _Mackonochie_, L.R. 4 Q.B.D. 770, and, on the other hand, of Lord
+Penzance in _Phillimore_ v. _Machon_, L.R. 1 P.D. 480). Theoretically
+still, in cases of sexual immorality, penance may be imposed. Monitions
+to amend may be decreed and be enforced by _significavit_ and writ _de
+contumace capiendo_, or by excommunication with imprisonment not to
+exceed six months (53 Geo. III. c. 127). The tribunals thus subsisting
+are the courts of the bishop and archbishop, the latter sometimes called
+the court of appeal of the province. Peculiar jurisdictions have been
+gradually taken away under the operation of the acts establishing the
+ecclesiastical commissioners. The appeal given to delegates appointed by
+the crown has been transferred, first by 2 & 3 Will. IV. c. 92 to the
+privy council, and then by 3 & 4 Will. IV. c. 41 to the judicial
+committee of the privy council. Bishops may now be summoned as assessors
+by 39 & 40 Vict. c. 59.
+
+There was in the time of Elizabeth, James I. and Charles I. a "Court of
+High Commission" with jurisdiction over laity and clergy, based on 1
+Eliz. c. i. s. 15, which was reckoned as an ecclesiastical judicature (5
+R. 1, _Cawdrey's case_) concurrent with the ordinary court Christian. It
+was created by virtue of the royal supremacy, and was taken away by 16
+Car. I. c. 11. As to its history see Stephen, _Hist. Crim. Law_, ii.
+414-428.
+
+In regard to clerical offences, 3 & 4 Vict. c. 86 (the "Church
+Discipline Act") creates new tribunals; and first a commission of
+inquiry appointed by the bishop of five persons, of whom the
+vicar-general, or an archdeacon, or a rural dean of the diocese must be
+one. If they report a _prima facie_ case, the bishop may (with the
+consent of parties) proceed to sentence. In the absence of such
+consent, the bishop may hear the cause with three assessors, of whom one
+shall be a barrister of seven years' standing and another the dean of
+the cathedral, or one of the archdeacons, or the chancellor. This court
+is called the "consistory" court, but is not the old consistory. Both
+these tribunals are new. But the bishop may instead send the cause, in
+first instance, to the old provincial court, to which appeal lies, if it
+be not so sent.
+
+The Public Worship Regulation Act (37 & 38 Vict. c. 85) gave criminal
+jurisdiction over beneficed clerks (concurrent with that of the tribunal
+under 3 & 4 Vict. c. 86) to the judge under the act in matters of the
+fabric, ornaments, furniture and decorations of churches, and the
+conduct of divine service, rites and ceremonies. The "judge" under the
+act is to be a barrister of ten years' standing, or an ex-judge of a
+superior secular court, appointed by the archbishops of Canterbury and
+York, with the approval of the crown, or, if they fail to appoint, by
+the crown. Proceedings under this act are to be deemed to be taken in
+the appropriate ancient ecclesiastical courts (_Green_ v. _Lord
+Penzance_, 6 A. C. 657). The judge under this act became (upon vacancies
+occurring) _ex officio_ official principal of the arches court of
+Canterbury and of the chancery court of York. This provision caused
+grave doubts to be entertained as to the canonical position of this
+statutory official principal.
+
+Finally, the Clergy Discipline Act 1892 (55 & 56 Vict. c. 32) creates
+yet a new court of first instance for the trial of clerical offences
+against morality in the shape of a consistory court, which is not the
+old court of that name, but is to comprehend the chancellor and five
+assessors (three clergymen and two laymen chosen from a prescribed
+list), with equal power with the chancellor on questions of fact. In
+many instances the conviction of a temporal court is made conclusive on
+the bishop without further trial. In regard to moral offences,
+jurisdiction under this act is exclusive. But it only applies to clerks
+holding preferment. Under all these three acts there is a final appeal
+to the judicial committee of the privy council.
+
+None of these acts applies to the trial of bishops, who are left to the
+old jurisdictions, or whatever may be held to be the old jurisdictions
+(with that of the Roman See eliminated). As to suffragan bishops in the
+province of Canterbury, see _Read_ v. _Bishop of Lincoln_, 13 P.D. 221,
+14 P.D. 88. (On general questions see Phillimore, _Ecc. Law_, 65, 73.)
+Despite the bishop of Lincoln's case, the law is in some uncertainty.
+
+Dilapidations are now not made matters of suit before the court, but of
+administrative action by the bishop.
+
+The subject matter of ecclesiastical jurisdiction has been gradually
+reduced in England, &c., by various causes. (1) The taking away of all
+matrimonial, testamentary and _ab intestate_ jurisdiction by 20 & 21
+Vict. c. 77 (testamentary, &c., England), c. 79 (testamentary, &c.,
+Ireland), c. 85 (matrimonial, England); 33 & 34 Vict. c. 110
+(matrimonial, Ireland). Matrimonial jurisdiction was taken from the
+bishop of Sodor and Man in 1884. (2) Since 6 & 7 Will. IV. c. 71, tithe
+has become, except in a few rare cases, tithe rent charge, and its
+recovery has been entirely an operation of secular law. Most kinds of
+offerings are now recoverable in secular courts. (3) Administration of
+pious gifts has passed to the court of chancery. (4) The enforcement of
+contractual promises has long been abandoned by the courts Christian
+themselves. (5) Church rates can no longer be enforced by suit (31 & 32
+Vict. c. 109). (6) _Defamation_ was taken away in England by 18 & 19
+Vict. c. 41, and in Ireland by 23 & 24 Vict. c. 32. (7) Laymen can no
+longer be tried in the spiritual courts for offences against clerks. (8)
+The jurisdiction for "brawling" in church, &c., is taken away by 23 & 24
+Vict. c. 32 in the case of the laity. In the case of persons in holy
+orders there is a concurrent jurisdiction of the two tribunals
+(_Valancy_ v. _Fletcher_, 1897, 1 Q.B. 265). This was an offence very
+frequently prosecuted in the courts Christian (see A.J. Stephens,
+_Ecclesiastical Statutes_, i. 336).
+
+The existing ecclesiastical jurisdiction in England is therefore now
+confined to the following points. (1) Discipline of the clergy. (2)
+Discipline of the laity in respect of sexual offences as already
+stated. (3) Control of lay office-bearers, church-wardens, sidesmen,
+organists, parish clerks, sextons. (4) Protection of the fabrics of
+churches, of churchyards, ornaments, fittings, &c., sanctioning by
+licence or faculty any additions or alterations, and preventing or
+punishing unauthorized dealings by proceedings on the criminal side of
+the courts. (5) Claims by individuals to particular seats in church or
+special places of sepulture. (6) Rare cases of personal or special
+tithes, offerings or pensions claimed by incumbents of benefices. In the
+Isle of Man and the Channel Islands courts Christian have now
+jurisdiction substantially as in England. In Jersey and in Guernsey
+there are courts of first instance with appeal to the bishop of
+Winchester. Ecclesiastical jurisdiction in Ireland was as in England
+till the Irish Church was disestablished in 1869 by 32 & 33 Vict. c. 42.
+
+
+  Ecclesiastical jurisdiction in non-established churches.
+
+The position of a disestablished or an unestablished Church is
+comparatively modern, and has given rise to new jural conceptions. These
+Churches are _collegia licita_ and come within the liberty of
+association so freely conceded in modern times. The relations of their
+bishops, priests or other ministers and lay office-bearers _inter se_
+and to their lay folk depend upon contract; and these contracts will be
+enforced by the ordinary courts of law. A consensual ecclesiastical
+jurisdiction is thus created, which has to this extent temporal
+sanction. _In foro conscientiae_ spiritual censures canonically imposed
+are as binding and ecclesiastical jurisdiction is as powerful as ever.
+
+Into the British-settled colonies no bishops were sent till 1787; and
+consequently there were no regular courts Christian. The bishop of
+London was treated as the diocesan bishop of the colonists in North
+America; and in order to provide for testamentary and matrimonial
+jurisdiction it was usual in the letters patent appointing the governor
+of a colony to name him ordinary. In New York state there is still a
+court called the surrogates court, surrogate being the regular name for
+a deputy ecclesiastical judge. In Lower Canada, by treaty, the Roman
+Catholic Church remained established.
+
+Throughout the United States, whatever may have been the position in
+some of them before their independence, the Church has now no position
+recognized by the State, but is just a body of believers whose relations
+are governed by contract and with whom ecclesiastical jurisdiction is
+consensual.
+
+The position is the same now through all the British colonies (except,
+as already mentioned, Lower Canada or Quebec). From 1787 onwards,
+colonial bishops and metropolitans were appointed by letters patent
+which purported to give them jurisdiction for disciplinary purposes. But
+a series of cases, of which the most remarkable was that _Re the Bishop
+of Natal_ (3 Moore P.C. N.S. A.D. 1864), decided that in colonies
+possessing self-governing legislatures such letters patent were of no
+value; and soon after the crown ceased to issue them, even for crown
+colonies.
+
+In India the metropolitan of Calcutta and the bishops of Madras and
+Bombay have some very limited jurisdiction which is conferred by letters
+patent under the authority of the statutes 53 Geo. III. c. 155 and 3 & 4
+Will. IV. c. 85. But the other Indian bishops have no position
+recognized by the State and no jurisdiction, except consensual.
+
+
+  Ecclesiastical jurisdiction in Scotland.
+
+The Church had the same jurisdiction in Scotland, and exercised it
+through similar courts to those which she had in England and France,
+till about 1570. As late as 1566 Archbishop Hamilton of Glasgow, upon
+his appointment, had restitution of his jurisdiction in the probate of
+testaments and other matters (Keith, _History of the Scottish Bishops_,
+Edinburgh, 1824, p. 38). There was an interval of uncertainty, with at
+any rate titular bishops, till 1592. Then parliament enacted a new
+system of Church courts which, though to some extent in its turn
+superseded by the revival of episcopacy under James VI., was revived or
+ratified by the act of 1690, c. 7, and stands to this day. It is a
+Presbyterian system, and the Scottish Episcopal Church is a
+disestablished and voluntary body since 1690.
+
+The Presbyterian courts thus created are arranged in ascending order:--
+
+(a) _Kirk Session_ consists of the minister of the parish and the
+"ruling elders" (who are elected by the session). It has cognizance of
+scandalous offences by laymen and punishes them by deprivation of
+religious privileges. It does not judge ministers (Brodie-Innes,
+_Comparative Principles of the Laws of England and Scotland_, 1903, p.
+144).
+
+(b) The _Presbytery_ has jurisdiction, partly appellate and partly
+original, over a number of parishes. There are now eighty-four
+presbyteries. These courts consist of every parochial minister or
+professor of divinity of any university within the limits, and of an
+elder commissioned from every kirk session. A minister is elected to
+preside as moderator. These courts judge ministers in first instance for
+scandalous conduct. As civil courts they judge in first instance all
+questions connected with glebes and the erection and repair of churches
+and manses. They regulate matters concerning public worship and
+ordinances, and have appellate jurisdiction from the kirk session.
+
+(c) The _Provincial Synod_ consists of a union of three or more
+presbyteries with the same members. There are now sixteen. They meet
+twice a year to hear appeals from presbyteries. No appeal can go direct
+to the General Assembly, _omisso medio_, unless the presbytery have so
+expressly directed, or unless there be no meeting of synod after the
+decision of the presbytery before the meeting of General Assembly.
+
+(d) The _General Assembly_ is the supreme ecclesiastical court of this
+system. It meets annually. The king's "lord high commissioner" attends
+the sittings; but does not intervene or take part in the court's
+decisions. The court consists of ministers and elders, elected from the
+presbyteries in specified proportions, and of commissioners from the
+four universities, the city of Edinburgh and the royal burghs. The
+Presbyterian Church in India sends one minister and one elder. The whole
+Assembly consists of 371 ministers and 333 elders. The jurisdiction is
+entirely appellate. The Assembly appoints a commission to exercise some
+of its functions during the intervals of its session. To this commission
+may be referred the cognizance of particular matters.
+
+Questions of _patronage_ now (by 37 & 38 Vict. c. 82) belong to the
+Church courts; but not questions of _lapse_ or _stipend_. Seats, seat
+rents, pews, the union and disjunction of parishes and formation of
+district parishes are of secular jurisdiction. Questions of tithes (or
+"teinds") and ministers' stipends were referred to commissioners by acts
+of the Scots parliaments beginning in 1607. The commissioners of teinds
+became a species of ecclesiastical court. By Scots act of 1707, c. 9,
+their powers were transferred to the judges of the court of session, who
+now constitute a "teind court" (Brodie-Innes, op. cit. pp. 138, 139).
+Matrimonial matters and those relating to wills and succession (called
+in Scotland "consistorial" causes) were in 1563 taken from the old
+bishops' courts and given to "commissaries" appointed by the crown with
+an appeal to the court of session, which by act 1609, c. 6, was declared
+the king's great consistory. They have remained matters of secular
+jurisdiction.
+
+The Scots ecclesiastical courts are entitled to the assistance of the
+secular courts to carry out their jurisdiction by "due assistance."
+Within the limits of their jurisdiction they are supreme. But if a court
+go outside its jurisdiction, or refuse to exercise powers conferred on
+it by law, the civil court may "reduce" (i.e. set aside) the sentence
+and award damages to the party aggrieved.
+
+
+  Protestant continental European states.
+
+With the Reformation in the 16th century, Church courts properly
+speaking disappeared from the non-episcopal religious communities which
+were established in Holland, in the Protestant states of Switzerland and
+of Germany, and in the then non-episcopal countries of Denmark and
+Norway.
+
+Discipline over ministers and other office-bearers was exercised by
+administrative methods in the form of trials before consistories or
+synods. To this extent ecclesiastical jurisdiction is still exercised in
+these countries. Consistories and synods have exercised discipline of a
+penitential kind over their lay members; but in later times their
+censures have generally ceased to carry temporal consequences.
+Ecclesiastical jurisdiction on the civil side for the trial of causes
+soon disappeared. Heresy has been treated as a crime to be tried in and
+punished by the ordinary courts of the country, as in the cases of
+Servetus (q.v.) and Grotius (q.v.).
+
+For the episcopal churches of Sweden and Finland the first constitution
+or "Church order" was formed in 1571. It provided for the visitation of
+the clergy by the bishop, and for the power of the clergy to exclude
+their lay folk from the Holy Communion, subject to appeal to the bishop.
+Both minor and major excommunication had been in use, and for a long
+time public penance was required. The procedure underwent great
+modification in 1686; but public penance was not taken away till 1855,
+and then confession to and absolution by the priest in the presence of
+witnesses was still required. Civil jurisdiction in causes appears to
+have been given up early (Cornelius, _Svenska Kirkaus Historia_, Upsala,
+1875, pp. 146, 186, 189, 285).
+
+
+  Roman Catholic countries.
+
+Over the rest of western continental Europe and in the colonies of
+Spain, Portugal and France, ecclesiastical jurisdiction remained
+generally in the state which we have already described till near the end
+of the 18th century. The council of Trent took away the jurisdiction of
+archdeacons in marriage questions. The testamentary jurisdiction
+disappeared (as already stated) in France. Disputed cases of contract
+were more often tried in the secular courts. Recourse to the secular
+prince by way of _appel comme d'abus_, or otherwise, became more
+frequent and met with greater encouragement. Kings began to insist upon
+trying ecclesiastics for treason or other political crimes in secular
+courts. So under the advice of his minister (the marquis of Pombal),
+King Joseph of Portugal in 1759-1760 claimed that the pope should give
+him permission to try in all cases clerics accused of treason, and was
+not content with the limited permission given to try and execute, if
+guilty, the Jesuits then accused of conspiring his death (_Life of
+Pombal_, by Count da Carnota, 1871, pp. 128, 141). But there was no
+sudden change in the position of the courts Christian till the French
+Revolution.
+
+In France a law of the Revolution (September 1790) purported to suppress
+all ecclesiastical jurisdictions. On the re-establishing of the Catholic
+religion on the basis of the new Concordat, promulgated 18 Germinal,
+year X. (April 8, 1802), no express provision was made for
+ecclesiastical jurisdictions; but several bishops did create new
+ecclesiastical tribunals, "officialities" (Migne, _Dict. de droit
+canon._, s.v.). The government in some cases recognized these tribunals
+as capable of judging ecclesiastical causes (Migne, _ubi sup._). In 1810
+the diocesan official of Paris entertained the cause between Napoleon
+and Josephine, and pronounced a decree of nullity (Migne, _ubi sup._
+s.v. "Causes"). Such litigation as still continued before the spiritual
+forum was, however, confined (save in the case of the matrimonial
+questions of princes) to the professional conduct of the clergy.
+
+Such neighbouring countries as were conquered by France or
+revolutionized after her pattern took the same course of suppressing
+their ecclesiastical jurisdictions. After 1814, some of these
+jurisdictions were revived. But the matter is now determined for all
+countries which have adopted codes, whether after the pattern of the
+Code Napoléon or otherwise. These countries have created a hierarchy of
+temporal courts competent to deal with every matter of which law takes
+cognizance, and a penal code which embraces and deals with all crimes or
+delicts which the state recognizes as offences. Hence, even in countries
+where the Roman Church is established, such as Belgium, Italy, the
+Catholic states of Germany and cantons of Switzerland, most of the Latin
+republics of America, and the province of Quebec, and _a fortiori_ where
+this Church is not established, there is now no discipline over the
+laity, except penitential, and no jurisdiction exercised in civil suits,
+except possibly the matrimonial questions of princes (of which there was
+an example in the case of the reigning prince of Monaco). In Spain
+causes of nullity and divorce _a thoro_, in Portugal causes of nullity
+between Catholics, are still for the court Christian. In Peru, the old
+ecclesiastical matrimonial jurisdiction substantially remains (Lehr, _Le
+Mariage dans les principaux pays_, 1899, arts. 362, 797, 772, 781).
+Otherwise these three countries are Code countries. In Austria, the
+ancient ecclesiastical jurisdiction was taken away by various acts of
+legislation from 1781 to 1856; even voluntary jurisdiction as to
+dispensations. The Concordat of 1856 and consequent legislation restored
+matrimonial jurisdiction to the courts Christian over marriages between
+Roman Catholics. In 1868 this was taken away. The Austrian bishops,
+however, maintain their tribunals for spiritual purposes, and insist
+that such things as divorce _a vinculo_ must be granted by their
+authority (Aichner, _Compendium juris ecclesiastici_, pp. 551-553).
+
+By consent and submission of her members, the Roman Church decides _in
+foro conscientiae_ questions of marriage, betrothal and legitimacy
+everywhere; but no temporal consequences follow except in Spain,
+Portugal and Peru.
+
+The position in France was the same as that in Belgium, Italy, &c., till
+1906, when the Church ceased to be established. The only Latin countries
+in which conflict has not arisen appear to be the principality of
+Andorra and the republic of San Marino (Giron y Areas, _Situación
+jurídica de la Iglesia Católica_, Madrid, 1905, p. 173 et seq.).
+
+Even as to the discipline of the Roman clergy it is only in certain
+limited cases that one can speak of ecclesiastical jurisdiction. Bishops
+and beneficed incumbents (_curés_) must be regularly tried; and where
+the Church is established the canonical courts are recognized. But the
+majority of parishes are served by mere _desservants_ or _vicaires_, who
+have no rights and can be recalled and dismissed by mere administrative
+order without trial (Migne, _ubi sup._ s.v. "Inamovibilité,"
+"Desservants").
+
+The Napoleonic legislation re-established the _appel comme d'abus_
+("_Articles organiques_," art. 6). The recourse was now to the council
+of state (see Migne, _ubi supra_, "Officialité"). But the revocation of
+a _desservant_, and the forbidding him the execution of his ministry in
+the diocese, was not a case in which the council of state would
+interfere (Migne, _ubi sup._ "Appel comme d'abus," "Conseil d'état").
+
+
+  Jurisdiction in Anglican communion.
+
+In those provinces of the Anglican communion where the Church is not
+established by the state, the tendency is not to attempt any external
+discipline over the laity; but on the other hand to exercise consensual
+jurisdiction over the clergy and office-bearers through courts nearly
+modelled on the old canonical patterns.
+
+
+  Modern jurisdiction of Church of Rome.
+
+In the Roman communion, on the other hand, both where the Church is
+established and where it is not, the tendency is to reduce the status of
+_curé_ to that of _desservant_, and to deal with all members of the
+priestly or lower orders by administrative methods. This practice
+obtains in all missionary countries, e.g. Ireland and also in Belgium
+(S.B. Smith, _Elements of Ecclesiastical Law_, New York, i. 197 et seq.;
+p. 403 et seq.; Tauber, _Manuale juris canonici_, Sabariae, 1904, p.
+277). In the United States, the 3rd plenary council of Baltimore in 1884
+provided that one rector out of ten should be irremovable (Smith, op.
+cit. i. 197, 419). In England there are few Roman "benefices" (E.
+Taunton, _Law of the Church_, London, 1906, s.v. "Benefice"). A
+_desservant_ has an informal appeal, by way of recourse, to the
+metropolitan and ultimately to the pope (Smith, op. cit. p. 201). The
+bishop's "official" is now universally called his vicar-general (except
+in France, where sometimes an _official_ is appointed _eo nomine_), and
+generally exercises both voluntary and contentious jurisdiction (op.
+cit. i. 377). As of old, he must be at least tonsured and without a wife
+living. At the Vatican Council, a desire was expressed that he should be
+a priest (ib.). He should be a doctor in theology or a licentiate in
+canon law (ib. p. 378). Whether a bishop is bound to appoint a
+vicar-general is still disputed (ib. p. 380; cf. _supra_; _contra_,
+Bouix, _Inst. Juris Canon. De Judic._ i. 405). In 1831 the pope enacted
+that in all the dioceses of the then Pontifical States, the court of
+first instance for the criminal causes of ecclesiastics should consist
+of the ordinary and four other judges. In the diocese of Rome, the
+court of the cardinal vicar-general consists of such vicar-general and
+four other prelates (Smith, _ubi supra_). In the Roman communion in
+England and the United States, there are commissions of investigation
+appointed to hear in first instance the criminal causes of clerks. They
+consist of five, or at least three, priests nominated by the bishop in
+and with the advice of the diocesan synod. In the United States, since
+1884, the bishop presides on these commissions. They report their
+opinions to the bishop, who passes final sentence (ib. ii. 129-131).
+
+"Exemptions" now include all the regular religious orders, i.e. those
+orders which have solemn vows. Over the members of these orders their
+superiors have jurisdiction and not the bishop. Otherwise if they live
+out of their monastery, or even within that enclosure so notoriously
+offend as to cause scandal. In the first case, they may be punished by
+the ordinary of the place, acting as delegate of the pope without
+special appointment (_Conc. Trid. Sess._ vi. c. 3). In the second case,
+the bishop may require the superior to punish within a certain time and
+to certify the punishment to him; in default he himself may punish
+(_Conc. Trid. Sess._ xxv. c. 14, cf. Smith, op. cit. i. 204-206). So,
+regulars having cure of souls are subject to the jurisdiction of the
+bishop in matters pertaining thereto (ib. p. 206). The exemption of
+regular religious orders may be extended to religious societies without
+solemn vows by special concession of the pope, as in the case of the
+Passionists and Redemptorists (ib. p. 205; Sanguineti, _Juris ecc.
+inst._, Rome, 1800, pp. 393, 394).
+
+Appeal lies, in nearly all cases, to the metropolitan (Smith, op. cit.
+pp. 219-223). Metropolitans usually now have a metropolitan tribunal
+distinct from their diocesan court (ib. ii. 141), but constructed on the
+same lines, with the metropolitan as judge and his vicar-general as
+vice-judge. In some "missionary" dioceses, the metropolitan, _qua_
+metropolitan, has a separate commission of investigation, to try the
+criminal causes of clerks, sentence being passed by himself or his
+vicar-general (ib. p. 142).
+
+The next step in the hierarchy, that of "primates" (_supra_), has "in
+the present state of the Church" ceased to exist for our purpose
+(Sanguineti, op. cit. p. 334), as a result of Tridentine legislation.
+The only appellate jurisdiction from the metropolitans is the Roman See.
+To it also lies a direct appeal from the court of first instance,
+_omisso medio_ (Smith, op. cit. i. 224). The pope's immediate and
+original jurisdiction in every diocese is now expressly affirmed by the
+Vatican Council (ib. p. 239). That original jurisdiction he reserves
+exclusively to himself in _causis majoribus_ (ib. pp. 249-250). These
+are (1) causes relating to elections, translations and deprivations of,
+and criminal prosecutions against, bishops, and (2) the matrimonial
+cases of princes (Taunton, op. cit. s.v. "Cause").
+
+
+  Eastern Church.
+
+In the Eastern Church, the early system of ecclesiastical judicature
+long continued. But a sacred character was ascribed to the emperors.
+They are "anointed lords like the bishops" (Balsamon, in _Conc. Ancyr.
+Can._ xii., representing the view of the 12th and 13th centuries).
+Bishops were often deposed by administrative order of the emperor;
+synods being expected afterwards to confirm, or rather accept, such
+order. The germ of this dealing with a _major causa_ may be found in the
+practice of the Arian emperors in the 4th century. The cause of Ignatius
+and Photius was dealt with in the 9th century by various synods; those
+in the East agreeing with the emperor's view for the time being, while
+those in the West acted with the pope. (The details are in Mansi, _Conc.
+in locis_, and in Hefele, _Conc. in locis_, more briefly. They are
+summarized in Landon, _Manual of Councils_, s.v. "Constantinople,"
+"Rome," and in E.S. Foulkes, _Manual of Ecclesiastical History_, s.v.
+"Century IX.") Since these transactions patriarchs have been deposed by
+the Byzantine emperors; and the Turkish sultans since the 15th century
+have assumed to exercise the same prerogative.
+
+The spiritual courts in the East have permanently acquired jurisdiction
+in the matrimonial causes of baptized persons; the Mahommedan
+governments allowing to Christians a personal law of their own. The
+patriarch of Constantinople is enabled to exercise an extensive
+criminal jurisdiction over Christians (Neale, _Hist. of the Eastern
+Church_, i. 30, 31).
+
+The empire of Russia has in the matter of ecclesiastical jurisdiction
+partly developed into other forms, partly systematized 4th century and
+later Byzantine rules. The provincial system does not exist; or it may
+be said that all Russia is one province. An exception should be made in
+the case of Georgia, which is governed by an "exarch," with three
+suffragans under him. In the remainder of the empire the titles of
+metropolitan, save in the case of the metropolitan of all Russia, and of
+archbishop, were and are purely honorary, and their holders have merely
+a diocesan jurisdiction (see Mouravieff, _History of the Russian
+Church_, translated Blackmore, 1842, translator's notes at pp. 370, 390,
+416 et seq.). So in Egypt the bishop or "pope" (afterwards patriarch) of
+Alexandria was the only true metropolitan (Neale, _History of the
+Eastern Church_, Gen. Introd. vol. i. p. 111). The metropolitan of
+Russia from the time of the conversion (A.D. 988) settled at Kiev, and
+his province was part of the patriarchate of Constantinople, and appeals
+lay to Constantinople. Many such appeals were taken, notably in the case
+of Leon, bishop of Rostov (Mouravieff, op. cit. p. 38). The
+metropolitical see was for a short time transferred to Vladimir and then
+finally to Moscow (Mouravieff, chs. iv., v.). After the taking of
+Constantinople in 1452, the Russian metropolitans were always chosen and
+consecrated in Russia, appeals ceased, and Moscow became _de facto_
+autocephalous (Joyce, ubi sup. p. 379; Mouravieff, op. cit. p. 126). The
+tsar Theodore in 1587 exercised the power of the Byzantine emperors by
+deposing the metropolitan, Dionysius Grammaticus (Mouravieff, p. 125).
+In 1587 the see of Moscow was raised to patriarchal rank with the
+consent of Constantinople, and the subsequent concurrence of Alexandria,
+Antioch and Jerusalem (ib. c. vi.). Moscow became the final court, in
+theory, as it had long been in practice. Certain religious houses,
+however, had their own final tribunals and were "peculiars," exempt from
+any diocesan or patriarchal jurisdiction for at least all causes
+relating to Church property (ib. p. 131).
+
+The subject matter of ecclesiastical jurisdiction in Russia during the
+whole patriarchal period included matrimonial and testamentary causes,
+inheritance and sacrilege, and many questions concerning the Church
+domains and Church property, as well as spiritual offences of clergy and
+laity (ib.). The bishops had consistorial courts; the patriarchs,
+chanceries and consistories (ib.). Bishops were judged in synod (see,
+e.g. the case of the archbishop of Polotsk in 1622, ib. p. 179) and only
+lawfully judged in synod (ib. p. 215).
+
+Clerks and the dependants of the metropolitan (afterwards the patriarch)
+appear to have been immune from secular jurisdiction, except in the case
+of crimes against life, from the time of Ivan the Terrible (ib. pp.
+180-181). The tsar Michael, in the earlier 17th century, confirmed these
+immunities in the case of the clergy of the patriarch's own diocese, but
+provided that in country places belonging to his diocese, monasteries,
+churches and lands should be judged in secular matters by the Court of
+the Great Palace, theoretically held before the tsar himself (ib. p.
+181). This tsar limited the "peculiar" monasteries to three, and gave
+the patriarch jurisdiction over them (ib.). The next tsar, Alexis,
+however, by his code instituted a "Monastery Court," which was a secular
+tribunal composed of laymen, to judge in civil suits against spiritual
+persons, and in matters arising out of their manors and properties (ib.
+p. 193). This court was not in operation during the time when the
+patriarch Nikon was also in effect first minister; but upon his decline
+exercised its full jurisdiction (ib. p. 216). Nikon was himself tried
+for abdicating his see, causing disorder in the realm, oppression and
+violence, first before a synod of Moscow composed of his suffragans and
+some Greek bishops, and afterwards before another synod in which sat the
+patriarchs of Alexandria and Antioch, the metropolitans of Servia and
+Georgia, the archbishops of Sinai and Wallachia, and the metropolitans
+of Nice, Amasis, Iconium, Trebizond, Varna and Scio, besides the Russian
+bishops. This synod in 1667 deposed Nikon, degraded him from holy
+orders, and sentenced him to perpetual penance in a monastery (ib. pp.
+220-232). The next tsar, Theodore, suppressed the secular "monastery
+court," and directed that all suits against spiritual persons should
+proceed only in the patriarchal "court of requests" (ib. p. 264). There
+was, however, a species of _appel comme d'abus_. Causes could be evoked
+to the tsar himself, "when any partiality of the judges in any affair in
+which they themselves were interested was discovered" (ib.).
+
+The old system was swept away by Peter the Great, who settled
+ecclesiastical jurisdiction substantially on its present basis. The
+patriarchate was abolished and its jurisdiction transferred by a council
+at St Petersburg in 1721 to a Holy Governing Synod. The change was
+approved by the four patriarchs of the East in 1723 (ib. chs.
+xv.-xvii.). Peter permanently transferred to the secular _forum_ the
+testamentary jurisdiction and that concerning inheritance, as also
+questions of "sacrilege" (ib. p. 264). As the result of a long series of
+legislation, beginning with him and ending with Catherine II., all
+church property of every kind was transferred to secular administration,
+allowances, according to fixed scales, being made for ministers, monks
+and fabrics (op. cit. translator's appendix i. p. 413 et seq.). There
+remain to the spiritual courts in Russia the purely ecclesiastical
+discipline of clerks and laity and matrimonial causes.
+
+The court of first instance is the "consistorial court" of the bishop.
+This consists of a small body of ecclesiastics. Its decisions must be
+confirmed by the bishop (op. cit. translator's appendix ii. pp.
+422-423). In the more important causes, as divorce (i.e. _a vinculo_),
+it only gives a provisional decision, which is reported by the bishop,
+with his own opinion, for final judgment, to the Most Holy Governing
+Synod.
+
+The governing synod is the final court of appeal. It consists of a small
+number of bishops and priests nominated by the tsar, and is assisted by
+a "procurator," who is a layman, who explains to it the limits of its
+jurisdiction and serves as the medium of communication between it and
+the autocrat and secular authorities. It deals with the secular crimes
+of spiritual persons, if of importance and if not capital (these last
+being reserved for the secular forum), and with heresy and schism. It is
+the only court which can try bishops or decree divorce. The tsar
+formally confirms its judgments; but sometimes reduces penalties in the
+exercise of the prerogative of mercy (see Mouravieff, op. cit. ch. xvii.
+translator's app. ii.).
+
+The governing synod now sits at St Petersburg, but appoints delegated
+commissions, with a portion of its jurisdiction, in Moscow and Georgia.
+The latter commission is presided over by the "exarch" (_supra_).
+
+Since the War of Independence, the kingdom of Greece has been
+ecclesiastically organized after the model of Russia, as one
+autocephalous "province," separated from its old patriarchate of
+Constantinople, with an honorary metropolitan and honorary archbishops
+(Neale, op. cit. Gen. Introd. vol. i.). The Holy Synod possesses the
+metropolitical jurisdiction. It sits at Athens. The metropolitan of
+Athens is president, and there are four other members appointed by the
+government in annual rotation from the senior bishops. There is attached
+to it a government commissioner, with no vote, but affixing his
+signature to the synodical judgments (Joyce, op. cit. p. 35).
+
+The subject matter of the jurisdiction of Hellenic courts Christian
+seems to be confined to strictly spiritual discipline, mainly in regard
+to the professional misconduct of the clergy. Imprisonment may be
+inflicted in these last cases (ib.). All matrimonial causes are heard by
+the secular tribunals (Lehr, op. cit. sec. 587).
+
+The bishop's consistorial court, consisting of himself and four priests,
+has a limited jurisdiction in first instance. Such a court can only
+suspend for seven days unless with the sanction of the Holy Synod
+(Joyce, op. cit.).
+
+The Holy Synod can only inflict temporary suspension, or imprisonment
+for fifteen days, unless with the sanction of the King's ministry.
+Deprivation, or imprisonment for more than two months, requires the
+approval of the king (ib.). The king or the ministry do not, however,
+rehear the cause by way of appeal, but merely restrain severity of
+sentence (ib.).
+
+The Church of Cyprus has been autocephalous since at any rate the
+oecumenical synod of Ephesus in 431. The episcopate now consists of an
+archbishop and three suffragans (Hackett, _Orthodox Church in Cyprus_,
+1901, ch. v. _et passim_). The final court is the island synod, which
+consists of the archbishop, his suffragans and four dignified priests.
+It has original and exclusive cognizance of causes of deposition of
+bishops (op. cit. pp. 260, 262).
+
+Each bishop is assisted by at least two officers with judicial or
+quasi-judicial powers, the "archimandrite" who adjudicates upon causes
+of revenue and the archdeacon who adjudicates on questions between
+deacons (op. cit. pp. 272-273). The "exarch" of the archbishop, who is a
+dignitary but not a bishop, has a seat in the provincial synod.
+
+In the Balkan States, the system--inherited from Byzantine and Turkish
+times--of ecclesiastical jurisdictions prevails, except that they are
+now autocephalous, and independent of the patriarch of Constantinople.
+Matrimonial causes in Servia are of ecclesiastical cognizance (Lehr, op.
+cit. sect. 901).
+
+  AUTHORITIES.--St Augustine, _Epistles_; _Codex Theodosianus_, edited
+  by Th. Mommsen and P.M. Meyer (1905); _Code and Novells of Emperor
+  Justinian_, ed. J. Gothofredus (1665); T. Balsamon, "In Conc. Ancyr."
+  in the _Corpus juris canonici_ (1879-1881); "_Hostiensis_" _Super
+  Decretum_; W. Lyndwood, _Provinciale_ (Oxford, 1679); Sir A.
+  Fitzherbert, _Natura brevium_ (1534); Sir T. Ridley, _View of the
+  Civile and Ecclesiastical Law_ (1607); J. Ayliffe, _Parergon juris
+  ecclesiastici_ (1726); J. Godolphin, _Abridgement of the Laws
+  Ecclesiastical_ (London, 1687); E. Gibson, _Codex juris ecclesiastici_
+  (Oxford, 1761); D. Covarruvias, _Opera omnia_ (Antwerp, 1638); Jean
+  Hardouin, _Concilia_ (1715); J.D. Mansi, _Concilia_ (1759-1798); E.
+  Stillingfleet, _Ecclesiastical Jurisdiction_ (1704); L.S. le Nain de
+  Tillemont, _Mémoires pour servir à l'histoire ecclésiastique_
+  (1701-1712); P.T. Durand de Maillane, _Dictionnaire du droit
+  canonique_ (1761); _Dictionnaire ecclésiastique et canonique_, par une
+  société de religieux (Paris, 1765); Z.B. van Espen, _Jus
+  ecclesiasticum universum_ (Louvain, 1720), _De recursu ad Principem,
+  observationes in Concilium Lateranense iv._; L. Thomassin, _Vetus et
+  nova disciplina ecc._ (1705-1706); W. Beveridge, _Synodicon_ (Oxford,
+  1672); J.A.S. da Carnota, _Life of Pombal_ (1843); J.P. Migne,
+  _Dictionnaire de droit canon._ (Paris, 1844); R. Keith, _History of
+  the Scottish Bishops_ (Edinburgh, 1824); P.N. Vives y Cebriá, _Usages
+  y demas derechos de Cataluña_ (1832); C.A. Cornelius, _Svenska Kyrkaus
+  Historia_ (Upsala, 1875); Mouravieff, _History of the Russian Church_
+  (trans. Blackmore, 1842); Ffoulkes, _Manual of Ecclesiastical History_
+  (1851); E.H. Landon, _Manual of Councils of the Church_ (1893); W.H.
+  Hale, _Precedents in Criminal Cases_ (London, 1847); E.B. Pusey,
+  _Councils of the Church_ (Oxford, 1857); C.J. von Hefele,
+  _Conciliengeschichte_ (Freiburg, 1855-1890); M. Gaudry, _Traité de la
+  législation des cultes_ (Paris, 1854); W. Stubbs, _Select Charters_
+  (Oxford, 1895); A.W. Haddan and W. Stubbs, _Councils and
+  Ecclesiastical Documents_ (Oxford, 1869); A.J. Stephens,
+  _Ecclesiastical Statutes_ (1845); H.C. Rothery, _Return of Cases
+  before Delegates_ (1864); J.W. Joyce, _The Sword and the Keys_ (2nd
+  ed., 1881); _Report of Ecclesiastical Courts Commission_ (1888); P.
+  Fournier, _Les Officialités au moyen âge_ (1880); S.B. Smith,
+  _Elements of Ecclesiastical Law_ (New York, 1889-1890); S. Sanguineti,
+  _Juris ecc. inst._ (Rome, 1890); J.F. Stephen, _History of the
+  Criminal Law of England_ (London, 1883); Pollock and Maitland,
+  _History of English Law before Edward I._ (1898); F.W. Maitland,
+  _Roman Canon Law in the Church of England_ (1898); R. Owen, _Canon
+  Law_ (1884); Sir R.J. Phillimore, _Ecclesiastical Law_ (2nd ed.,
+  1895); J.W. Brodie-Innes, _Comparative Principles of the Laws of
+  England and Scotland_ (1903); R.B. Merriman, _Life and Letters of
+  Thomas Cromwell_ (1902); S. Aichner, _Compendium juris ecclesiast._
+  (8th ed., Brixen, 1905, especially in regard to Austro-Hungarian
+  Empire); J. Hackett, _History of the Orthodox Church in Cyprus_
+  (1901); Tauber, _Manuale juris canonici_ (1906); E.L. Taunton, _Law of
+  the Church_ (London, 1906); _Report of Royal Commission on
+  Ecclesiastical Discipline_ (1906).     (W. G. F. P.)
+
+
+
+
+ECCLESIASTICAL LAW, in its broadest sense, the sum of the authoritative
+rules governing the Christian Church, whether in its internal polity or
+in its relations with the secular power. Since there are various
+churches, widely differing alike in their principles and practice, it
+follows that a like difference exists in their ecclesiastical law, which
+is the outcome of their corporate consciousness as modified by their
+several relations to the secular authority. At the outset a distinction
+must be made between churches which are "established" and those that are
+"free." The ecclesiastical laws of the latter are, like the rules of a
+private society or club, the concern of the members of the church only,
+and come under the purview of the state only in so far as they come in
+conflict with the secular law (e.g. polygamy among the Mormons, or
+violation of the trust-deeds under which the property of a church is
+held). In the case of "established" Churches, on the other hand,
+whatever the varying principle on which the system is based, or the
+difference in its practical application, the essential conditions are
+that the ecclesiastical law is also the law of the land, the decisions
+of the church courts being enforced by the civil power. This holds good
+both of the Roman Catholic Church, wherever this is recognized as the
+"state religion," of the Oriental Churches, whether closely identified
+with the state itself (as in Russia), or endowed with powers over
+particular nationalities within the state (as in the Ottoman empire),
+and of the various Protestant Churches established in Great Britain and
+on the continent of Europe.
+
+Writers on the theory of ecclesiastical law, moreover, draw a fundamental
+distinction between that of the Church of Rome and that of the Protestant
+national or territorial Churches. This distinction is due to the claim of
+the Roman Catholic Church to be the _only_ Church, her laws being thus of
+universal obligation; whereas the laws of the various established
+Protestant Churches are valid--at least so far as legal obligation is
+concerned--only within the limits of the countries in which they are
+established. The practical effects of this distinction have been, and
+still are, of enormous importance. The Roman Catholic Church, even when
+recognized as the state religion, is nowhere "established" in the sense
+of being identified with the state, but is rather an _imperium in
+imperio_ which negotiates on equal terms with the state, the results
+being embodied in concordats (q.v.) between the state and the pope as
+head of the Church. The concordats are of the nature of truces in the
+perennial conflict between the spiritual and secular powers, and imply in
+principle no surrender of the claims of the one to those of the other.
+Where the Roman Catholic Church is not recognized as a state religion, as
+in the United States or in the British Islands, she is in the position of
+a "free Church," her jurisdiction is only _in foro conscientiae_, and her
+ecclesiastical laws have no validity from the point of view of the state.
+On the other hand, the root principle of the ecclesiastical law of the
+established Protestant Churches is the rejection of alien jurisdiction
+and the assertion of the supremacy of the state. The theory underlying
+this may vary. The sovereign may be regarded, as in the case of the
+Russian emperor or of the English kings from the Reformation to the
+Revolution, as the vicar of God in all causes spiritual as well as
+temporal within his realm. As the first fervent belief in the divine
+right of kings faded, however, a new basis had to be discovered for a
+relation between the spiritual and temporal powers against which Rome had
+never ceased to protest. This was found in the so-called "collegial"
+theory of Church government (_Kollegialsystem_), which assumed a sort of
+tacit concordat between the state and the religious community, by which
+the latter vests in the former the right to exercise a certain part of
+the _jus in sacra_ properly inherent in the Church (see PUFENDORF,
+SAMUEL). This had great and lasting effects on the development of the
+theory of Protestant ecclesiastical law on the continent of Europe. In
+England, on the other hand, owing to the peculiar character of the
+Reformation there and of the Church that was its outcome, no theory of
+the ecclesiastical law is conceivable that would be satisfactory at once
+to lawyers and to all schools of opinion within the Church. This has been
+abundantly proved by the attitude of increasing opposition assumed by the
+clergy, under the influence of the Tractarian movement, towards the civil
+power in matters ecclesiastical, an attitude impossible to justify on any
+accepted theory of the Establishment (see below).
+
+Protestant ecclesiastical law, then, is distinguished from that of the
+Roman Catholic Church (1) by being more limited in its scope, (2) by
+having for its authoritative source, not the Church only or even mainly,
+but the Church in more or less complete union with or subordination to
+the State, the latter being considered, equally with the Church, as an
+organ of the will of God. The ecclesiastical law of the Church of Rome,
+on the other hand, whatever its origin, is now valid only in so far as
+it has the sanction of the authority of the Holy See. And here it must
+be noted that the "canon law" is not identical with the "ecclesiastical
+law" of the Roman Catholic Church. By the canon law is meant,
+substantially, the contents of the _Corpus juris canonici_, which have
+been largely superseded or added to by, e.g. the canons of the council
+of Trent and the Vatican decrees. The long projected codification of the
+whole of the ecclesiastical law of the Church of Rome, a work of
+gigantic labour, was not taken in hand until the pontificate of Pius X.
+(See also CANON LAW and ECCLESIASTICAL JURISDICTION.)
+
+The ecclesiastical law of England is in complete dependence upon the
+authority of the state. The Church of England cannot be said, from a
+legal point of view, to have a corporate existence or even a
+representative assembly. The Convocation of York and the Convocation of
+Canterbury are provincial assemblies possessing no legislative or
+judicial authority; even such purely ecclesiastical questions as may be
+formally commended to their attention by "letters of business" from the
+crown can only be finally settled by act of parliament. The
+ecclesiastical courts are for the most part officered by laymen, whose
+subordination to the archbishops and bishops is purely formal, and the
+final court of appeal is the Judicial Committee of the Privy Council. In
+like manner changes in the ecclesiastical law are made directly by
+parliament in the ordinary course of legislation, and in point of fact a
+very large portion of the existing ecclesiastical law consists of acts
+of parliament.
+
+The sources of the ecclesiastical law of England are thus described by
+Dr. Richard Burn (_The Ecclesiastical Law_, 9th ed., 1842):--"The
+ecclesiastical law of England is compounded of these four main
+ingredients--the civil law, the canon law, the common law, and the
+statute law. And from these, digested in their proper rank and
+subordination, to draw out one uniform law of the church is the purport
+of this book. When these laws do interfere and cross each other, the
+order of preference is this:--'The civil law submitteth to the canon
+law; both of these to the common law; and all three to the statute law.
+So that from any one or more of these, without all of them together, or
+from all of them together without attending to their comparative
+obligation, it is not possible to exhibit any distinct prospect of the
+English ecclesiastical constitution.' Under the head of statute law Burn
+includes 'the Thirty-nine Articles of Religion, agreed upon in
+Convocation in the year 1562; and in like manner the Rubric of the Book
+of Common Prayer, which, being both of them established by Acts of
+Parliament, are to be esteemed as part of the statute law.'"
+
+The first principle of the ecclesiastical law in England is the
+assertion of the supremacy of the crown, which in the present state of
+the constitution means the same thing as the supremacy of parliament.
+This principle has been maintained ever since the Reformation. Before
+the Reformation the ecclesiastical supremacy of the pope was recognized,
+with certain limitations, in England, and the Church itself had some
+pretensions to ecclesiastical freedom. The freedom of the Church is, in
+fact, one of the standing provisions of those charters on which the
+English constitution was based. The first provision of Magna Carta is
+_quod ecclesia Anglicana libera sit_. By the various enactments of the
+period of the Reformation the whole constitutional position of the
+Church, not merely with reference to the pope but with reference to the
+state, was definitely fixed. The legislative power of convocation was
+held to extend to the clergy only, and even to that extent required the
+sanction and assent of the crown. The common law courts controlled the
+jurisdiction of the ecclesiastical courts, claiming to have "the
+exposition of such statutes or acts of parliament as concern either the
+extent of the jurisdiction of these courts or the matters depending
+before them. And therefore if these courts either refuse to allow these
+acts of parliament, or expound them in any other sense than is truly and
+properly the exposition of them, the king's great courts of common law
+may prohibit and control them."
+
+The design of constructing a code of ecclesiastical laws was entertained
+during the period of the Reformation, but never carried into effect. It
+is alluded to in various statutes of the reign of Henry VIII., who
+obtained power to appoint a commission to examine the old ecclesiastical
+laws, with a view of deciding which ought to be kept and which ought to
+be abolished; and in the meantime it was enacted that "such canons,
+institutions, ordinances, synodal or provincial or other ecclesiastical
+laws or jurisdictions spiritual as be yet accustomed and used here in
+the Church of England, which necessarily and conveniently are requisite
+to be put in ure and execution for the time, not being repugnant,
+contrarient, or derogatory to the laws or statutes of the realm, nor to
+the prerogatives of the royal crown of the same, or any of them, shall
+be occupied, exercised, and put in ure for the time with this realm" (35
+Henry VIII. c. 16, 25 c. 19, 27 c. 8).
+
+The work was actually undertaken and finished in the reign of Edward VI.
+by a sub-committee of eight persons, under the name of the _Reformatio
+legum ecclesiasticarum_, which, however, never obtained the royal
+assent. Although the powers of the 25 Henry VIII. c. 1 were revived by
+the 1 Elizabeth c. 1, the scheme was never executed, and the
+ecclesiastical laws remained on the footing assigned to them in that
+statute--so much of the old ecclesiastical laws might be used as had
+been actually in use, and was not repugnant to the laws of the realm.
+
+The statement is, indeed, made by Sir R. Phillimore (_Ecclesiastical
+Law_, 2nd ed., 1895) that the "Church of England has at all times,
+before and since the Reformation, claimed the right of an independent
+Church in an independent kingdom, to be governed by the laws which she
+has deemed it expedient to adopt." This position can only be accepted if
+it is confined, as the authorities cited for it are confined, to the
+resistance of interference from abroad. If it mean that the Church, as
+distinguished from the kingdom, has claimed to be governed by laws of
+her own making, all that can be said is that the claim has been
+singularly unsuccessful. From the time of the Reformation no change has
+been made in the law of the Church which has not been made by the king
+and parliament, sometimes indirectly, as by confirming the resolutions
+of convocation, but for the most part by statute. The list of statutes
+cited in Sir R. Phillimore's _Ecclesiastical Law_ fills eleven pages. It
+is only by a kind of legal fiction akin to the "collegial" theory
+mentioned above, that the Church can be said to have deemed it expedient
+to adopt these laws.
+
+The terms on which the Church Establishment of Ireland was abolished, by
+the Irish Council Act of 1869, may be mentioned. By sect. 20 the present
+ecclesiastical law was made binding on the members for the time being of
+the Church, "as if they had mutually contracted and agreed to abide by
+and observe the same"; and by section 21 it was enacted that the
+ecclesiastical courts should cease after the 1st of January 1871, and
+that the ecclesiastical laws of Ireland, except so far as relates to
+matrimonial causes and matters, should cease to exist as law. (See also
+ENGLAND, CHURCH OF; ESTABLISHMENT; &c.)
+
+  AUTHORITIES.--The number of works on ecclesiastical law is very great,
+  and it must suffice here to mention a few of the more conspicuous
+  modern ones: Ferdinand Walter, _Lehrbuch des Kirchenrechts aller
+  christlichen Konfessionen_ (14th ed., Bonn, 1871); G. Phillips,
+  _Kirchenrecht_, Bde. i.-vii. (Regensburg, 1845-1872) incomplete; the
+  text-book by Cardinal Hergenröther (q.v.); P. Hinschius, _Kirchenrecht
+  der Katholiken und Protestanten in Deutschland_, 6 Bde. (Berlin, 1869
+  sqq.), only the Catholic part, a masterly and detailed survey of the
+  ecclesiastical law, finished; Sir Robert Phillimore, _Eccl. Law of the
+  Church of England_ (2nd ed., edited by Sir Walter Phillimore, 2 vols.,
+  London, 1895). For further references see CANON LAW, and the article
+  "Kirchenrecht" in Herzog-Hauck, _Realencyklopädie_ (ed. Leipzig,
+  1901).
+
+
+
+
+ECCLESIASTICUS (abbreviated to _Ecclus._), the alternative title given
+in the English Bible to the apocryphal book otherwise called "The Wisdom
+of Jesus the son of Sirach." The Latin word _ecclesiasticus_ is,
+properly speaking, not a name, but an epithet meaning "churchly," so
+that it would serve as a designation of any book which was read in
+church or received ecclesiastical sanction, but in practice
+Ecclesiasticus has become a by-name for the Wisdom of Sirach. The true
+name of the book appears in the authorities in a variety of forms, the
+variation affecting both the author's name and the description of his
+book. The writer's full name is given in 1. 27 (Heb. text) as "Simeon
+the son of Jeshua (i.e. Jesus) the son of Eleazar the son of Sira." In
+the Greek text this name appears as "Jesus son of Sirach Eleazar"
+(probably a corruption of the Hebrew reading), and the epithet "of
+Jerusalem" is added, the translator himself being resident in Egypt. The
+whole name is shortened sometimes to "Son of Sira," _Ben Sira_ in
+Hebrew, _Bar Sira_ in Aramaic, and sometimes (as in the title prefixed
+in the Greek cod. B) to _Sirach_. The work is variously described as the
+_Words_ (Heb. text), the _Book_ (Talmud), the _Proverbs_ (Jerome), or
+the _Wisdom_ of the son of Sira (or Sirach).
+
+Of the date of the book we have only one certain indication. It was
+translated by a person who says that he "came into Egypt in the 38th
+year of Euergetes the king" (Ptolemy VII.), i.e. in 132 B.C., and that
+he executed the work some time later. The translator believed that the
+writer of the original was his own grandfather (or ancestor, [Greek:
+pappos]). It is therefore reasonable to suppose that the book was
+composed not later than the first half of the 2nd century B.C., or (if
+we give the looser meaning to [Greek: pappos]) even before the beginning
+of the century. Arguments for a pre-Maccabean date may be derived (a)
+from the fact that the book contains apparently no reference to the
+Maccabean struggles, (b) from the eulogy of the priestly house of Zadok
+which fell into disrepute during these wars for independence.
+
+In the Jewish Church Ecclesiasticus hovered on the border of the canon;
+in the Christian Church it crossed and recrossed the border. The book
+contains much which attracted and also much which repelled Jewish
+feeling, and it appears that it was necessary to pronounce against its
+canonicity. In the Talmud (Sanhedrin 100 b) Rabbi Joseph says that it is
+forbidden to read (i.e. in the synagogue) the book of ben Sira, and
+further that "if our masters had not hidden the book (i.e. declared it
+uncanonical), we might interpret the good things which are in it"
+(Schechter, _J. Q. Review_, iii. 691-692). In the Christian Church it
+was largely used by Clement of Alexandria (c. A.D. 200) and by St
+Augustine. The lists of the Hebrew canon, however, given by Melito (c.
+A.D. 180) and by Origen (c. A.D. 230) rightly exclude Ecclesiasticus,
+and Jerome (c. A.D. 390-400) writes: "Let the Church read these two
+volumes (Wisdom of Solomon and Ecclesiasticus) for the instruction of
+the people, not for establishing the authority of the dogmas of the
+Church" (_Praefatio in libros Salomonis_). In the chief MS. of the
+Septuagint, cod. B, Ecclesiasticus comes between Wisdom and Esther, no
+distinction being drawn between canonical and uncanonical. In the
+Vulgate it immediately precedes Isaiah. The council of Trent declared
+this book and the rest of the books reckoned in the Thirty-nine Articles
+as apocryphal to be canonical.
+
+The text of the book raises intricate problems which are still far from
+solution. The original Hebrew (rediscovered in fragments and published
+between 1896 and 1900) has come down to us in a mutilated and corrupt
+form. The beginning as far as iii. 7 is lost. There is a gap from xvi.
+26 to xxx. 11. There are marginal readings which show that two different
+recensions existed once in Hebrew. The Greek version exists in two
+forms--(a) that preserved in cod. B and in the other uncial MSS., (b)
+that preserved in the cursive codex 248 (Holmes and Parsons). The former
+has a somewhat briefer text, the latter agrees more closely with the
+Hebrew text. The majority of Greek cursives agree generally with the
+Latin Vulgate, and offer the fuller text in a corrupt form. The Syriac
+(Peshitta) version is paraphrastic, but on the whole it follows the
+Hebrew text. Owing to the mutilation of the Hebrew by the accidents of
+time the Greek version retains its place as the chief authority for the
+text, and references by chapter and verse are usually made to it.
+
+Bickell and D.S. Margoliouth have supposed that the Hebrew text
+preserved in the fragments is not original, but a retranslation from the
+Greek or the Syriac or both. This view has not commended itself to the
+majority of scholars, but there is at least a residuum of truth in it.
+The Hebrew text, as we have it, has a history of progressive corruption
+behind it, and its readings can often be emended from the Septuagint,
+e.g. xxxvii. 11 (read [Hebrew: umira] for the meaningless [Hebrew:
+umerer]). The Hebrew marginal readings occasionally seem to be
+translations from the Greek or Syriac, e.g. xxxviii. 4 ([Hebrew: bara
+shamaym] for [Greek: ektisen pharmaka]). More frequently, however,
+strange readings of the Greek and Syriac are to be explained as
+corruptions of our present Hebrew. Substantially our Hebrew must be
+pronounced original.
+
+The restoration of a satisfactory text is beyond our hopes. Even before
+the Christian era the book existed in two recensions, for we cannot
+doubt, after reading the Greek translator's preface, that the translator
+amplified and paraphrased the text before him. It is probable that at
+least one considerable omission must be laid to his charge, for the hymn
+preserved in the Hebrew text after ch. li. 12 is almost certainly
+original. Ancient translators allowed themselves much liberty in their
+work, and Ecclesiasticus possessed no reputation for canonicity in the
+2nd century B.C. to serve as a protection for its text. Much, however,
+may be done towards improving two of the recensions which now lie before
+us. The incomplete Hebrew text exists in four different MSS., and the
+study of the peculiarities of these had already proved fruitful. The
+Syriac text, made without doubt from the Hebrew, though often
+paraphrastic is often suggestive. The Greek translation, made within a
+century or half-century of the writing of the book, must possess great
+value for the criticism of the Hebrew text. The work of restoring true
+Hebrew readings may proceed with more confidence now that we have
+considerable portions of the Hebrew text to serve as a model. For the
+restoration of the Greek text we have, besides many Greek MSS., uncial
+and cursive, the old Latin, the Syro-Hexaplar, the Armenian, Sahidic and
+Ethiopic versions, as well as a considerable number of quotations in the
+Greek and Latin Fathers. Each of the two recensions of the Greek must,
+however, be separately studied, before any restoration of the original
+Greek text can be attempted.
+
+The uncertainty of the text has affected both English versions
+unfavourably. The Authorized Version, following the corrupt cursives, is
+often wrong. The Revised Version, on the other hand, in following the
+uncial MSS. sometimes departs from the Hebrew, while the Authorized
+Version with the cursives agrees with it. Thus the Revised Version (with
+codd. [Hebrew: alef]*, A, B, C) omits the whole of iii. 19, which the
+Authorized Version retains, but for the clause, "Mysteries are revealed
+unto the meek," the Authorized Version has the support of the Hebrew,
+Syriac and cod. 248. Sometimes both versions go astray in places in
+which the Hebrew text recommends itself as original by its vigour; e.g.
+in vii. 26, where the Hebrew is,
+
+  Hast thou a wife? abominate her not.
+  Hast thou a hated wife? trust not in her.
+
+Again in ch. xxxviii. the Hebrew text in at least two interesting
+passages shows its superiority over the text which underlies both
+English versions.
+
+                _Hebrew._                _Revised Version (similarly
+                                             Authorized Version)._
+
+  ver. 1.  Acquaint thyself with a       Honour a physician according
+           physician before thou have    to thy need of him with the
+           need of him.                  honours due unto him.
+
+  ver. 15. He that sinneth against his   He that sinneth before his
+           Maker will behave himself     Maker, let him fall into the
+           proudly against a physician.  hands of the physician.
+
+In the second instance, while the Hebrew says that the man who rebels
+against his Heavenly Benefactor will _a fortiori_ rebel against a human
+benefactor, the Greek text gives a cynical turn to the verse, "Let the
+man who rebels against his true benefactor be punished through the
+tender mercies of a quack." The Hebrew text is probably superior also in
+xliv. 1, the opening words of the eulogy of the Fathers: "Let me now
+praise favoured men," i.e. men in whom God's grace was shown. The Hebrew
+phrase is "men of grace," as in v. 10. The Greek text of v. 1, "famous
+men," seems to be nothing but a loose paraphrase, suggested by v. 2,
+"The Lord manifested in them great glory."
+
+In character and contents Ecclesiasticus resembles the book of Proverbs.
+It consists mainly of maxims which may be described in turn as moral,
+utilitarian and secular. Occasionally the author attacks prevalent
+religious opinions, e.g. the denial of free-will (xv. 11-20), or the
+assertion of God's indifference towards men's actions (xxxv. 12-19).
+Occasionally, again, Ben Sira touches the highest themes, and speaks of
+the nature of God: "He is All" (xliii. 27); "He is One from everlasting"
+(xlii. 21, Heb. text); "The mercy of the Lord is upon all flesh" (xviii.
+13). Though the book is imitative and secondary in character it contains
+several passages of force and beauty, e.g. ch. ii. (how to fear the
+Lord); xv. 11-20 (on free-will); xxiv. 1-22 (the song of wisdom); xlii.
+15-25 (praise of the works of the Lord); xliv. 1-15 (the well-known
+praise of famous men). Many detached sayings scattered throughout the
+book show a depth of insight, or a practical shrewdness, or again a
+power of concise speech, which stamps them on the memory. A few examples
+out of many may be cited. "Call no man blessed before his death" (xi.
+28); "He that toucheth pitch shall be defiled" (xiii. 1); "He hath not
+given any man licence to sin" (xv. 20); "Man cherisheth anger against
+man; and doth he seek healing from the Lord?" (xxviii. 3); "Mercy is
+seasonable ... as clouds of rain" (xxxv. 20); "All things are double one
+against another: and he hath made nothing imperfect" (xlii. 24, the
+motto of Butler's _Analogy_); "Work your work before the time cometh,
+and in his time he will give you your reward" (li. 30). In spite,
+however, of the words just quoted it cannot be said that Ben Sira
+preaches a hopeful religion. Though he prays, "Renew thy signs, and
+repeat thy wonders ... Fill Sion with thy majesty and thy Temple with
+thy glory" (xxxvi. 6, 14 [19], Heb. text), he does not look for a
+Messiah. Of the resurrection of the dead or of the immortality of the
+soul there is no word, not even in xli. 1-4, where the author exhorts
+men not to fear death. Like the Psalmist (Ps. lxxxviii. 10, 11) he asks,
+"Who shall give praise to the Most High in the grave?" In his maxims of
+life he shows a somewhat frigid and narrow mind. He is a pessimist as
+regards women; "From a woman was the beginning of sin; and because of
+her we all die" (xxv. 24). He does not believe in home-spun wisdom; "How
+shall he become wise that holdeth the plough?" (xxxviii. 25). Artificers
+are not expected to pray like the wise man; "In the handywork of their
+craft is their prayer" (v. 34). Merchants are expected to cheat; "Sin
+will thrust itself in between buying and selling" (xxvii. 2).
+
+  BIBLIOGRAPHY.--The literature of Ecclesiaticus has grown very
+  considerably since the discovery of the first Hebrew fragment in 1896.
+  A useful summary of it is found at the end of Israel Levi's article,
+  "Sirach," in the _Jewish Encyclopedia_. Eberhard Nestle's article in
+  Hastings's _Dictionary of the Bible_ is important for its
+  bibliographical information as well as in other respects. A complete
+  edition of the Hebrew fragments in collotype facsimile was published
+  jointly by the Oxford and Cambridge Presses in 1901. J.H.A. Hart's
+  edition of cod. 248 throws much light on some of the problems of this
+  book. It contains a fresh collation of all the chief authorities
+  (Heb., Syr., Syr.-Hex., Lat. and Gr.) for the text, together with a
+  complete textual commentary.
+
+  The account given in the _Synopsis_ attributed to Athanasius (Migne,
+  _P.G._, iv. 375-384) has an interest of its own. The beginning is
+  given in the Authorized Version as "A prologue made by an uncertain
+  author."     (W. E. B.)
+
+
+
+
+ECGBERT, or ECGBERHT (d. 839), king of the West Saxons, succeeded to the
+throne in 802 on the death of Beorhtric. It is said that at an earlier
+period in his life he had been driven out for three years by Offa and
+Beorhtric. The accession of Ecgbert seems to have brought about an
+invasion by Æthelmund, earl of the Hwicce, who was defeated by Weoxtan,
+earl of Wiltshire. In 815 Ecgbert ravaged the whole of the territories
+of the West Welsh, which probably at this time did not include much more
+than Cornwall. The next important occurrence in the reign was the defeat
+of Beornwulf of Mercia at a place called Ellandun in 825. After this
+victory Kent, Surrey, Sussex and Essex submitted to Wessex; while the
+East Anglians, who slew Beornwulf shortly afterwards, acknowledged
+Ecgbert as overlord. In 829 the king conquered Mercia, and Northumbria
+accepted him as overlord. In 830 he led a successful expedition against
+the Welsh. In 836 he was defeated by the Danes, but in 838 he won a
+battle against them and their allies the West Welsh at Hingston Down in
+Cornwall. Ecgbert died in 839, after a reign of thirty-seven years, and
+was succeeded by his son Æthelwulf. A somewhat difficult question has
+arisen as to the parentage of Ecgbert. Under the year 825 the Chronicle
+states that in his eastern conquests Ecgbert recovered what had been
+the rightful property of his kin. The father of Ecgbert was called
+Ealhmund, and we find an Ealhmund, king in Kent, mentioned in a charter
+dated 784, who is identified with Ecgbert's father in a late addition to
+the Chronicle under the date 784. It is possible, however, that the
+Chronicle in 825 refers to some claim through Ine of Wessex from whose
+brother Ingeld Ecgbert was descended.
+
+  See _Anglo-Saxon Chronicle_, edited by Earle and Plummer (Oxford,
+  1899); W. de G. Birch, _Cartularium Saxonicum_ (London, 1885-1893).
+  Also a paper by Sir H.H. Howorth in _Numismatic Chronicle_, third
+  series, vol. xx. pp. 66-87 (reprinted separately, London, 1900), where
+  attention is called to the peculiar dating of several of Ecgbert's
+  charters, and the view is put forward that he remained abroad
+  considerably later than the date given by the Chronicle for his
+  accession. On the other hand a charter in Birch, _Cart. Sax._,
+  purporting to date from 799, contains the curious statement that peace
+  was made between Coenwulf and Ecgbert in that year.
+
+
+
+
+ECGBERT, or ECGBERHT (d. 766), archbishop of York, was made bishop of
+that see in 734 by Ceolwulf, king of Northumbria, succeeding Wilfrid II.
+on the latter's resignation. The pall was sent him in 735 and he became
+the first northern archbishop after Paulinus. He was the brother of
+Eadberht, who ruled Northumbria 737-758. He was the recipient of the
+famous letter of Bede, dealing with the evils arising from spurious
+monasteries. Ecgberht himself wrote a _Dialogus Ecclesiasticae
+Institutionis_, a _Penitentiale_ and a _Pontificale_. He was a
+correspondent of St Boniface, who asks him to support his censure of
+Æthelbald of Mercia.
+
+  See Bede, _Continuatio_, sub. ann. 732, 735, 766, and _Epistola ad
+  Ecgberctum_ (Plummer, Oxford, 1896); _Chronicle_, sub ann. 734, 735,
+  738, 766 (Earle and Plummer, Oxford, 1899); Haddan and Stubbs,
+  _Councils and Ecclesiastical Documents_ (Oxford, 1869-1878), iii.
+  403-431; _Proceedings of Surtees Society_ (Durham, 1853).
+
+
+
+
+ECGFRITH (d. 685), king of Northumbria, succeeded his father Oswio in
+671. He was married to Æthelthryth, daughter of Anna of East Anglia,
+who, however, took the veil shortly after Ecgfrith's accession, a step
+which possibly led to his long quarrel with Wilfrid archbishop of York.
+Ecgfrith married a second wife, Eormenburg, before 678, the year in
+which he expelled Wilfrid from his kingdom. Early in his reign he
+defeated the Picts who had risen in revolt. Between 671 and 675 Ecgfrith
+defeated Wulfhere of Mercia and seized Lindsey. In 679, however, he was
+defeated by Æthelred of Mercia, who had married his sister Osthryth, on
+the river Trent. Ecgfrith's brother Ælfwine was killed in the battle,
+and the province of Lindsey was given up when peace was restored at the
+intervention of Theodore of Canterbury. In 684 Ecgfrith sent an
+expedition to Ireland under his general Berht, which seems to have been
+unsuccessful. In 685, against the advice of Cuthbert, he led a force
+against the Picts under his cousin Burde, son of Bile, was lured by a
+feigned flight into their mountain fastnesses, and slain at
+Nechtanesmere (now Dunnichen) in Forfarshire. Bede dates the beginning
+of the decline of Northumbria from his death. He was succeeded by his
+brother Aldfrith.
+
+  See Eddius, _Vita Wilfridi_ (Raine, _Historians of Church of York_,
+  Rolls, Series, London, 1879-1894), 19, 20, 24, 34, 39, 44; Bede,
+  _Hist. Eccl._ (Plummer, Oxford, 1896), iii. 24, iv. 5, 12, 13, 18, 19,
+  21, 26.
+
+
+
+
+ECGONINE, in chemistry, C9H15NO3, a cycloheptane derivative with a
+nitrogen bridge. It is obtained by hydrolysing cocaine with acids or
+alkalis, and crystallizes with one molecule of water, the crystals
+melting at 198° to 199° C. It is laevo-rotatory, and on warming with
+alkalis gives iso-ecgonine, which is dextro-rotatory. It is a tertiary
+base, and has also the properties of an acid and an alcohol. When boiled
+with caustic baryta it gives methylamine. It is the carboxylic acid
+corresponding to tropine, for it yields the same products on oxidation,
+and by treatment with phosphorus pentachloride is converted into
+anhydroecgonine, C9H13NO2, which, when heated to 280° C. with
+hydrochloric acid, splits out carbon dioxide and yields tropidine,
+C8H13N. Anhydroecgonine melts at 235° C., and has an acid and a basic
+character. It is an unsaturated compound, and on oxidation with
+potassium permanganate gives succinic acid. It is apparently a tropidine
+monocarboxylic acid, for on exhaustive methylation it yields
+cycloheptatriene-1·3·5-carboxylic acid-7. Sodium in amyl alcohol
+solution reduces it to hydroecgonidine C9H15NO2, while moderate
+oxidation by potassium permanganate converts it into _norecgonine_. The
+presence of the heptamethylene ring in these compounds is shown by the
+production of suberone by the exhaustive methylation, &c., of
+hydroecgonidine ethyl ester (see POLYMETHYLENES and TROPINE). The above
+compounds may be represented as:
+
+  CH2--CH----CH COOH   CH2--CH----CH COOH   CH2--CH------CH COOH
+  |    |     |         |    |     |         |    |       |
+  |    N CH3 CH OH     |    N CH3 CH        |    N CH3 CH2
+  |    |     |         |    |     ||        |    |       |
+  CH2--CH----CH2       CH2--CH----CH        CH2--CH------CH2
+     Ecgonine           Anhydroecgonine        Hydroecgonine
+
+
+
+
+ECHEGARAY Y EIZAGUIRRE, JOSÉ (1833-   ), Spanish mathematician,
+statesman and dramatist, was born at Madrid in March 1833, and was
+educated at the grammar school of Murcia, whence he proceeded to the
+Escuela de Caminos at the capital. His exemplary diligence and unusual
+mathematical capacity were soon noticed. In 1853 he passed out at the
+head of the list of engineers, and, after a brief practical experience
+at Almería and Granada, was appointed professor of pure and applied
+mathematics in the school where he had lately been a pupil. His
+_Problemas de geometría analítica_ (1865) and _Teorías modernas de la
+física unidad de las fuerzas materiales_ (1867) are said to be esteemed
+by competent judges. He became a member of the Society of Political
+Economy, helped to found _La Revista_, and took a prominent part in
+propagating Free Trade doctrines in the press and on the platform. He
+was clearly marked out for office, and when the popular movement of 1868
+overthrew the monarchy, he resigned his post for a place in the
+revolutionary cabinet. Between 1867 and 1874 he acted as minister of
+education and of finance; upon the restoration of the Bourbon dynasty he
+withdrew from politics, and won a new reputation as a dramatist.
+
+As early as 1867 he wrote _La Hija natural_, which was rejected, and
+remained unknown till 1877, when it appeared with the title of _Para tal
+culpa tal pena_. Another play, _La Última Noche_, also written in 1867,
+was produced in 1875; but in the latter year Echegaray was already
+accepted as the successful author of _El Libro talonario_, played at the
+Teatro de Apolo on the 18th of February 1874, under the transparent
+pseudonym of Jorge Hayaseca. Later in the same year Echegaray won a
+popular triumph with _La Esposa del vengador_, in which the good and bad
+qualities--the clever stagecraft and unbridled extravagance--of his
+later work are clearly noticeable. From 1874 onwards he wrote, with
+varying success, a prodigious number of plays. Among the most favourable
+specimens of his talent may be mentioned _En el puño de la espada_
+(1875); _O locura ó santidad_ (1877), which has been translated into
+Swedish and Italian; _En el seno de la muerte_ (1879), of which there
+exists an admirable German version by Fastenrath. _El gran Galeoto_
+(1881), perhaps the best of Echegaray's plays in conception and
+execution, has been translated into several languages, and still holds
+the stage. The humorous proverb, _¿Piensa mal y acertarás?_ exemplifies
+the author's limitations, but the attempt is interesting as an instance
+of ambitious versatility. His susceptibility to new ideas is illustrated
+in such pieces as _Mariana_ (1892), _Mancha que limpia_ (1895), _El Hijo
+de Don Juan_ (1892), and _El Loco Dios_ (1900): these indicate a close
+study of Ibsen, and _El Loco Dios_ more especially might be taken for an
+unintentional parody of Ibsen's symbolism.
+
+Echegaray succeeded to the literary inheritance of López de Ayala and of
+Tamayo y Baus; and though he possesses neither the poetic imagination of
+the first nor the instinctive tact of the second, it is impossible to
+deny that he has reached a larger audience than either. Not merely in
+Spain, but in every land where Spanish is spoken, and in cities as
+remote from Madrid as Munich and Stockholm, he has met with an
+appreciation incomparably beyond that accorded to any other Spanish
+dramatist of recent years. But it would be more than usually rash to
+prophesy that this exceptional popularity will endure. There have been
+signs of a reaction in Spain itself, and Echegaray's return to politics
+in 1905 was significant enough. He applies his mathematics to the
+drama; no writer excels him in artful construction, in the arrangement
+of dramatic scenes, in mere theatrical technique, in the focusing of
+attention on his chief personages. These are valuable gifts in their
+way, and Echegaray has, moreover, a powerful, gloomy imagination, which
+is momentarily impressive. In the drawing of character, in the invention
+of felicitous phrase, in the contrivance of verbal music, he is
+deficient. He alternates between the use of verse and prose; and his
+hesitancy in choosing a medium of expression is amply justified, for the
+writer's prose is not more distinguished than his verse. These serious
+shortcomings may explain the diminution of his vogue in Spain; they will
+certainly tell against him in the estimate of posterity.     (J. F.-K.)
+
+
+
+
+ÉCHELON (Fr. from _échelle_, ladder), in military tactics, a formation
+of troops in which each body of troops is retired on, but not behind,
+the flank of the next in front, the position of the whole thus
+resembling the steps of a staircase. To form échelon from line, the
+parts of the line move off, each direct to its front, in succession, so
+that when the formation is completed the rightmost body, for example, is
+farthest advanced, the one originally next on its left is to the left
+rear, a third is to the left rear of the second, and so on. The word is
+also used more loosely to express successive lines, irrespective of
+distances and relative positions, e.g. the "second échelon of ammunition
+supply," which is fully a day's march behind the first.
+
+
+
+
+ECHIDNA, or PORCUPINE ANT-EATER (_Echidna aculeata_), one of the few
+species of Monotremata, the lowest subclass of Mammalia, forming the
+family Echidnidae. It is a native of Australia, where it chiefly abounds
+in New South Wales, inhabiting rocky and mountainous districts, where it
+burrows among the loose sand, or hides itself in crevices of rocks. In
+size and appearance it bears a considerable resemblance to the hedgehog,
+its upper surface being covered over with strong spines directed
+backwards, and on the back inwards, so as to cross each other on the
+middle line. The spines in the neighbourhood of the tail form a tuft
+sufficient to hide that almost rudimentary organ. The head is produced
+into a long tubular snout, covered with skin for the greater part of its
+length. The opening of the mouth is small, and from it the echidna puts
+forth its long slender tongue, lubricated with a viscous secretion, by
+means of which it seizes the ants and other insects on which it feeds.
+It has no teeth. Its legs are short and strong, and form, with its broad
+feet and large solid nails, powerful burrowing organs. In common with
+the other monotremes, the male echidna has its heel provided with a
+sharp hollow spur, connected with a secreting gland, and with muscles
+capable of pressing the secretion from the gland into the spur. It is a
+nocturnal or crepuscular animal, generally sleeping during the day, but
+showing considerable activity by night. When attacked it seeks to escape
+either by rolling itself into a ball, its erect spines proving a
+formidable barrier to its capture, or by burrowing into the sand, which
+its powerful limbs enable it to do with great celerity. "The only mode
+of carrying the creature," writes G. Bennett (_Gatherings of a
+Naturalist in Australasia_), "is by one of the hind legs; its powerful
+resistance and the sharpness of the spines will soon oblige the captor,
+attempting to seize it by any other part of the body, to relinquish his
+hold." In a younger stage of their development, however, the young are
+carried in a temporary abdominal pouch, to which they are transferred
+after hatching, and into which open the mammary glands. The echidnas are
+exceedingly restless in confinement, and constantly endeavour by
+burrowing to effect their escape. From the quantity of sand and mud
+always found in the alimentary canal of these animals, it is supposed
+that these ingredients must be necessary to the proper digestion of
+their insect food.
+
+There are two varieties of this species, the Port Moresby echidna and
+the hairy echidna. The last-mentioned is found in south-eastern New
+Guinea, Australia and Tasmania. In all the spines are mixed with hair;
+in the Tasmanian race they are nearly hidden by the long harsh fur. Of
+the three-clawed echidnas (_Proechidna_) confined to New Guinea there
+are two species, Bruijn's echidna (_P. bruijnii_), discovered in 1877 in
+the mountains on the north-east coast at an elevation of 3500 ft., and
+the black-spined echidna (_P. nigroaculeata_) of larger size--the type
+specimen measuring 31 in., as against 24 in.--with shorter
+claws.
+
+
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Encyclopaedia Britannica, 11th
+Edition, Volume 8, Slice 9, by Various
+
+*** END OF THIS PROJECT GUTENBERG EBOOK ENCYCLOPAEDIA BRITANNICA ***
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+<pre>
+
+The Project Gutenberg EBook of Encyclopaedia Britannica, 11th Edition,
+Volume 8, Slice 9, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 9
+       "Dyer" to "Echidna"
+
+Author: Various
+
+Release Date: January 8, 2011 [EBook #34878]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ENCYCLOPAEDIA BRITANNICA ***
+
+
+
+
+Produced by Marius Masi, Don Kretz and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+</pre>
+
+
+
+<table border="0" cellpadding="10" style="background-color: #dcdcdc; color: #696969; " summary="Transcriber's note">
+<tr>
+<td style="width:25%; vertical-align:top">
+Transcriber&rsquo;s note:
+</td>
+<td class="norm">
+A few typographical errors have been corrected. They
+appear in the text <span class="correction" title="explanation will pop up">like this</span>, and the
+explanation will appear when the mouse pointer is moved over the marked
+passage. Sections in Greek will yield a transliteration
+when the pointer is moved over them, and words using diacritic characters in the
+Latin Extended Additional block, which may not display in some fonts or browsers, will
+display an unaccented version. <br /><br />
+<a name="artlinks">Links to other EB articles:</a> Links to articles residing in other EB volumes will
+be made available when the respective volumes are introduced online.
+</td>
+</tr>
+</table>
+<div style="padding-top: 3em; ">&nbsp;</div>
+
+<h2>THE ENCYCLOP&AElig;DIA BRITANNICA</h2>
+
+<h2>A DICTIONARY OF ARTS, SCIENCES, LITERATURE AND GENERAL INFORMATION</h2>
+
+<h3>ELEVENTH EDITION</h3>
+<div style="padding-top: 3em; ">&nbsp;</div>
+
+<hr class="full" />
+<h3>VOLUME VIII SLICE IX<br /><br />
+Dyer to Echidna</h3>
+<hr class="full" />
+<div style="padding-top: 3em; ">&nbsp;</div>
+
+<p class="center1" style="font-size: 150%; font-family: 'verdana';">Articles in This Slice</p>
+<table class="reg" style="width: 90%; font-size: 90%; border: gray 2px solid;" cellspacing="8" summary="Contents">
+
+<tr><td class="tcl"><a href="#ar1">DYER, SIR EDWARD</a></td> <td class="tcl"><a href="#ar65">EAST LIVERPOOL</a></td></tr>
+<tr><td class="tcl"><a href="#ar2">DYER, JOHN</a></td> <td class="tcl"><a href="#ar66">EAST LONDON</a></td></tr>
+<tr><td class="tcl"><a href="#ar3">DYER, THOMAS HENRY</a></td> <td class="tcl"><a href="#ar67">EASTON</a></td></tr>
+<tr><td class="tcl"><a href="#ar4">DYMOKE</a></td> <td class="tcl"><a href="#ar68">EAST ORANGE</a></td></tr>
+<tr><td class="tcl"><a href="#ar5">DYNAMICS</a></td> <td class="tcl"><a href="#ar69">EASTPORT</a></td></tr>
+<tr><td class="tcl"><a href="#ar6">DYNAMITE</a></td> <td class="tcl"><a href="#ar70">EAST PROVIDENCE</a></td></tr>
+<tr><td class="tcl"><a href="#ar7">DYNAMO</a></td> <td class="tcl"><a href="#ar71">EAST PRUSSIA</a></td></tr>
+<tr><td class="tcl"><a href="#ar8">DYNAMOMETER</a></td> <td class="tcl"><a href="#ar72">EASTWICK, EDWARD BACKHOUSE</a></td></tr>
+<tr><td class="tcl"><a href="#ar9">DYNASTY</a></td> <td class="tcl"><a href="#ar73">EATON, DORMAN BRIDGMAN</a></td></tr>
+<tr><td class="tcl"><a href="#ar10">DYSART</a></td> <td class="tcl"><a href="#ar74">EATON, MARGARET O&rsquo;NEILL</a></td></tr>
+<tr><td class="tcl"><a href="#ar11">DYSENTERY</a></td> <td class="tcl"><a href="#ar75">EATON, THEOPHILUS</a></td></tr>
+<tr><td class="tcl"><a href="#ar12">DYSPEPSIA</a></td> <td class="tcl"><a href="#ar76">EATON, WILLIAM</a></td></tr>
+<tr><td class="tcl"><a href="#ar13">DYSTELEOLOGY</a></td> <td class="tcl"><a href="#ar77">EATON, WYATT</a></td></tr>
+<tr><td class="tcl"><a href="#ar14">DZUNGARIA</a></td> <td class="tcl"><a href="#ar78">EAU CLAIRE</a></td></tr>
+<tr><td class="tcl"><a href="#ar15">E</a></td> <td class="tcl"><a href="#ar79">EAU DE COLOGNE</a></td></tr>
+<tr><td class="tcl"><a href="#ar16">EA</a></td> <td class="tcl"><a href="#ar80">EAUX-BONNES</a></td></tr>
+<tr><td class="tcl"><a href="#ar17">EABANI</a></td> <td class="tcl"><a href="#ar81">EAVES</a></td></tr>
+<tr><td class="tcl"><a href="#ar18">EACHARD, JOHN</a></td> <td class="tcl"><a href="#ar82">EAVESDRIP</a></td></tr>
+<tr><td class="tcl"><a href="#ar19">EADBALD</a></td> <td class="tcl"><a href="#ar83">EBBW VALE</a></td></tr>
+<tr><td class="tcl"><a href="#ar20">EADIE, JOHN</a></td> <td class="tcl"><a href="#ar84">EBEL, HERMANN WILHELM</a></td></tr>
+<tr><td class="tcl"><a href="#ar21">EADMER</a></td> <td class="tcl"><a href="#ar85">EBEL, JOHANN GOTTFRIED</a></td></tr>
+<tr><td class="tcl"><a href="#ar22">EADS, JAMES BUCHANAN</a></td> <td class="tcl"><a href="#ar86">EBER, PAUL</a></td></tr>
+<tr><td class="tcl"><a href="#ar23">EAGLE</a></td> <td class="tcl"><a href="#ar87">EBERBACH</a> (town of Germany)</td></tr>
+<tr><td class="tcl"><a href="#ar24">EAGLEHAWK</a></td> <td class="tcl"><a href="#ar88">EBERBACH</a> (monastery of Germany)</td></tr>
+<tr><td class="tcl"><a href="#ar25">EAGRE</a></td> <td class="tcl"><a href="#ar89">EBERHARD</a></td></tr>
+<tr><td class="tcl"><a href="#ar26">EAKINS, THOMAS</a></td> <td class="tcl"><a href="#ar90">EBERHARD, CHRISTIAN AUGUST GOTTLOB</a></td></tr>
+<tr><td class="tcl"><a href="#ar27">EALING</a></td> <td class="tcl"><a href="#ar91">EBERHARD, JOHANN AUGUSTUS</a></td></tr>
+<tr><td class="tcl"><a href="#ar28">EAR</a></td> <td class="tcl"><a href="#ar92">EBERLIN, JOHANN ERNST</a></td></tr>
+<tr><td class="tcl"><a href="#ar29">EARL</a></td> <td class="tcl"><a href="#ar93">EBERS, GEORG MORITZ</a></td></tr>
+<tr><td class="tcl"><a href="#ar30">EARLE, JOHN</a></td> <td class="tcl"><a href="#ar94">EBERSWALDE</a></td></tr>
+<tr><td class="tcl"><a href="#ar31">EARLE, RALPH</a></td> <td class="tcl"><a href="#ar95">EBERT, FRIEDRICH ADOLF</a></td></tr>
+<tr><td class="tcl"><a href="#ar32">EARL MARSHAL</a></td> <td class="tcl"><a href="#ar96">EBINGEN</a></td></tr>
+<tr><td class="tcl"><a href="#ar33">EARLOM, RICHARD</a></td> <td class="tcl"><a href="#ar97">EBIONITES</a></td></tr>
+<tr><td class="tcl"><a href="#ar34">EARLSTON</a></td> <td class="tcl"><a href="#ar98">EBNER-ESCHENBACH, MARIE</a></td></tr>
+<tr><td class="tcl"><a href="#ar35">EARLY, JUBAL ANDERSON</a></td> <td class="tcl"><a href="#ar99">EBOLI</a></td></tr>
+<tr><td class="tcl"><a href="#ar36">EARLY ENGLISH PERIOD</a></td> <td class="tcl"><a href="#ar100">EBONY</a></td></tr>
+<tr><td class="tcl"><a href="#ar37">EARN</a></td> <td class="tcl"><a href="#ar101">EBRARD, JOHANNES HEINRICH AUGUST</a></td></tr>
+<tr><td class="tcl"><a href="#ar38">EARNEST</a></td> <td class="tcl"><a href="#ar102">EBRO</a></td></tr>
+<tr><td class="tcl"><a href="#ar39">EAR-RING</a></td> <td class="tcl"><a href="#ar103">EBROÏN</a></td></tr>
+<tr><td class="tcl"><a href="#ar40">EARTH</a></td> <td class="tcl"><a href="#ar104">EBUR&#256;CUM</a></td></tr>
+<tr><td class="tcl"><a href="#ar41">EARTH, FIGURE OF THE</a></td> <td class="tcl"><a href="#ar105">EÇA DE QUEIROZ, JOSÉ MARIA</a></td></tr>
+<tr><td class="tcl"><a href="#ar42">EARTH CURRENTS</a></td> <td class="tcl"><a href="#ar106">ÉCARTÉ</a></td></tr>
+<tr><td class="tcl"><a href="#ar43">EARTH-NUT</a></td> <td class="tcl"><a href="#ar107">ECBATANA</a></td></tr>
+<tr><td class="tcl"><a href="#ar44">EARTH PILLAR</a></td> <td class="tcl"><a href="#ar108">ECCARD, JOHANN</a></td></tr>
+<tr><td class="tcl"><a href="#ar45">EARTHQUAKE</a></td> <td class="tcl"><a href="#ar109">ECCELINO DA ROMANO</a></td></tr>
+<tr><td class="tcl"><a href="#ar46">EARTH-STAR</a></td> <td class="tcl"><a href="#ar110">ECCENTRIC</a></td></tr>
+<tr><td class="tcl"><a href="#ar47">EARTHWORM</a></td> <td class="tcl"><a href="#ar111">ECCHELLENSIS, ABRAHAM</a></td></tr>
+<tr><td class="tcl"><a href="#ar48">EARWIG</a></td> <td class="tcl"><a href="#ar112">ECCLES</a></td></tr>
+<tr><td class="tcl"><a href="#ar49">EASEMENT</a></td> <td class="tcl"><a href="#ar113">ECCLESFIELD</a></td></tr>
+<tr><td class="tcl"><a href="#ar50">EAST, ALFRED</a></td> <td class="tcl"><a href="#ar114">ECCLESHALL</a></td></tr>
+<tr><td class="tcl"><a href="#ar51">EAST ANGLIA </a></td> <td class="tcl"><a href="#ar115">ECCLESIA</a></td></tr>
+<tr><td class="tcl"><a href="#ar52">EASTBOURNE</a></td> <td class="tcl"><a href="#ar116">ECCLESIASTES</a></td></tr>
+<tr><td class="tcl"><a href="#ar53">EAST CHICAGO</a></td> <td class="tcl"><a href="#ar117">ECCLESIASTICAL COMMISSIONERS</a></td></tr>
+<tr><td class="tcl"><a href="#ar54">EASTER</a></td> <td class="tcl"><a href="#ar118">ECCLESIASTICAL JURISDICTION</a></td></tr>
+<tr><td class="tcl"><a href="#ar55">EASTER ISLAND</a></td> <td class="tcl"><a href="#ar119">ECCLESIASTICAL LAW</a></td></tr>
+<tr><td class="tcl"><a href="#ar56">EASTERN BENGAL AND ASSAM</a></td> <td class="tcl"><a href="#ar120">ECCLESIASTICUS</a></td></tr>
+<tr><td class="tcl"><a href="#ar57">EASTERN QUESTION, THE</a></td> <td class="tcl"><a href="#ar121">ECGBERT</a> (king of the West Saxons)</td></tr>
+<tr><td class="tcl"><a href="#ar58">EAST GRINSTEAD</a></td> <td class="tcl"><a href="#ar122">ECGBERT</a> (archbishop of York)</td></tr>
+<tr><td class="tcl"><a href="#ar59">EAST HAM</a></td> <td class="tcl"><a href="#ar123">ECGFRITH</a></td></tr>
+<tr><td class="tcl"><a href="#ar60">EASTHAMPTON</a></td> <td class="tcl"><a href="#ar124">ECGONINE</a></td></tr>
+<tr><td class="tcl"><a href="#ar61">EAST HAMPTON</a></td> <td class="tcl"><a href="#ar125">ECHEGARAY Y EIZAGUIRRE, JOSÉ</a></td></tr>
+<tr><td class="tcl"><a href="#ar62">EAST INDIA COMPANY</a></td> <td class="tcl"><a href="#ar126">ÉCHELON</a></td></tr>
+<tr><td class="tcl"><a href="#ar63">EAST INDIES</a></td> <td class="tcl"><a href="#ar127">ECHIDNA</a></td></tr>
+<tr><td class="tcl"><a href="#ar64">EASTLAKE, SIR CHARLES LOCK</a></td> <td>&nbsp;</td></tr>
+</table>
+
+<hr class="art" />
+<p><span class="pagenum"><a name="page755" id="page755"></a>755</span></p>
+<p><span class="bold">DYER, SIR EDWARD<a name="ar1" id="ar1"></a></span> (d. 1607), English courtier and poet,
+son of Sir Thomas Dyer, Kt., was born at Sharpham Park,
+Somersetshire. He was educated, according to Anthony à Wood,
+either at Balliol College or at Broadgates Hall, Oxford. He
+left the university without taking a degree, and after some time
+spent abroad appeared at Queen Elizabeth&rsquo;s court. His first
+patron was the earl of Leicester, who seems to have thought
+of putting him forward as a rival to Sir Christopher Hatton
+in the queen&rsquo;s favour. He is mentioned by Gabriel Harvey
+with Sidney as one of the ornaments of the court. Sidney in his
+will desired that his books should be divided between Fulke
+Greville (Lord Brooke) and Dyer. He was employed by
+Elizabeth on a mission (1584) to the Low Countries, and in 1589
+was sent to Denmark. In a commission to inquire into manors
+unjustly alienated from the crown in the west country he did
+not altogether please the queen, but he received a grant of some
+forfeited lands in Somerset in 1588. He was knighted and made
+chancellor of the order of the Garter in 1596. William Oldys
+says of him that he &ldquo;would not stoop to fawn,&rdquo; and some of
+his verses seem to show that the exigencies of life at court
+oppressed him. He was buried at St Saviour&rsquo;s, Southwark, on
+the 11th of May 1607. Wood says that many esteemed him
+to be a Rosicrucian, and that he was a firm believer in alchemy.
+He had a great reputation as a poet among his contemporaries,
+but very little of his work has survived. Puttenham in the
+<i>Arte of English Poesie</i> speaks of &ldquo;Maister Edward Dyar, for
+Elegie most sweete, solempne, and of high conceit.&rdquo; One of
+the poems universally accepted as his is &ldquo;My Mynde to me a
+kingdome is.&rdquo; Among the poems in <i>England&rsquo;s Helicon</i> (1600),
+signed S.E.D., and included in Dr A.B. Grosart&rsquo;s collection
+of Dyer&rsquo;s works (<i>Miscellanies of the Fuller Worthies Library</i>,
+vol. iv., 1876) is the charming pastoral &ldquo;My Phillis hath the
+morninge sunne,&rdquo; but this comes from the <i>Phillis</i> of Thomas
+Lodge. Grosart also prints a prose tract entitled <i>The Prayse
+of Nothing</i> (1585). The <i>Sixe Idillia</i> from Theocritus, reckoned
+by J.P. Collier among Dyer&rsquo;s works, were dedicated to, not
+written by, him.</p>
+
+
+<hr class="art" />
+<p><span class="bold">DYER, JOHN<a name="ar2" id="ar2"></a></span> (<i>c.</i> 1700-1758), British poet, the son of a solicitor,
+was born in 1699 or 1700 at Aberglasney, in Carmarthenshire.
+He was sent to Westminster school and was destined for
+the law, but on his father&rsquo;s death he began to study painting.
+He wandered about South Wales, sketching and occasionally
+painting portraits. In 1726 his first poem, <i>Grongar Hill</i>, appeared
+in a miscellany published by Richard Savage, the poet. It was
+an irregular ode in the so-called Pindaric style, but Dyer entirely
+rewrote it into a loose measure of four cadences, and printed it
+separately in 1727. It had an immediate and brilliant success.
+<i>Grongar Hill</i>, as it now stands, is a short poem of only 150 lines,
+describing in language of much freshness and picturesque charm
+the view from a hill overlooking the poet&rsquo;s native vale of Towy.
+A visit to Italy bore fruit in <i>The Ruins of Rome</i> (1740), a descriptive
+piece in about 600 lines of Miltonic blank verse. He was
+ordained priest in 1741, and held successively the livings of
+Calthorp in Leicestershire, Belchford (1751), Coningsby (1752),
+and Kirby-on-Bane (1756), the last three being Lincolnshire
+parishes. He married, in 1741, a Miss Ensor, said to be descended
+from the brother of Shakespeare. In 1757 he published his
+longest work, the didactic blank-verse epic of <i>The Fleece</i>, in four
+books, discoursing of the tending of sheep, of the shearing and
+preparation of the wool, of weaving, and of trade in woollen
+manufactures. The town took no interest in it, and Dodsley
+facetiously prophesied that &ldquo;Mr Dyer would be buried in
+woollen.&rdquo; He died at Coningsby of consumption, on the 15th
+of December 1758.</p>
+
+<div class="condensed">
+<p>His <span class="correction" title="amended from peoms">poems</span> were collected by Dodsley in 1770, and by Mr Edward
+Thomas in 1903 for the <i>Welsh Library</i>, vol. iv.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">DYER, THOMAS HENRY<a name="ar3" id="ar3"></a></span> (1804-1888), English historical and
+antiquarian writer, was born in London on the 4th of May
+1804. He was originally intended for a business career, and for
+some time acted as clerk in a West India house; but finding his
+services no longer required after the passing of the Negro Emancipation
+Act, he decided to devote himself to literature. In 1850
+he published the <i>Life of Calvin</i>, a conscientious and on the whole
+impartial work, though the character of Calvin is somewhat
+harshly drawn, and his influence in the religious world generally
+is insufficiently appreciated. Dyer&rsquo;s first historical work was
+the <i>History of Modern Europe</i> (1861-1864; 3rd ed. revised and
+continued to the end of the 19th century, by A. Hassall, 1901),
+a meritorious compilation and storehouse of facts, but not very
+readable. The <i>History of the City of Rome</i> (1865) down to
+the end of the middle ages was followed by the <i>History of the
+Kings of Rome</i> (1868), which, upholding against the German
+school the general credibility of the account of early Roman
+history, given in Livy and other classical authors, was violently
+attacked by J.R. Seeley and the <i>Saturday Review</i>, as showing
+ignorance of the comparative method. More favourable opinions
+of the work were expressed by others, but it is generally agreed
+that the author&rsquo;s scholarship is defective and that his views are
+far too conservative. <i>Roma Regalis</i> (1872) and <i>A Plea for Livy</i>
+(1873) were written in reply to his critics. Dyer frequently
+visited Greece and Italy, and his topographical works are
+probably his best; amongst these mention may be made of
+<i>Pompeii, its History, Buildings and Antiquities</i> (1867, new ed.
+in Bohn&rsquo;s <i>Illustrated Library</i>), and <i>Ancient Athens, its History,
+Topography and Remains</i> (1873). His last publication was <i>On
+Imitative Art</i> (1882). He died at Bath on the 30th of January
+1888.</p>
+
+
+<hr class="art" />
+<p><span class="bold">DYMOKE,<a name="ar4" id="ar4"></a></span> the name of an English family holding the office
+of king&rsquo;s champion. The functions of the champion were to ride
+into Westminster Hall at the coronation banquet, and challenge
+all comers to impugn the king&rsquo;s title (see <span class="sc"><a href="#artlinks">Champion</a></span>). The
+earliest record of the ceremony at the coronation of an English
+king dates from the accession of Richard II. On this occasion
+the champion was Sir John Dymoke (d. 1381), who held the
+manor of Scrivelsby, Lincolnshire, in right of his wife Margaret,
+granddaughter of Joan Ludlow, who was the daughter and
+co-heiress of Philip Marmion, last Baron Marmion. The Marmions
+claimed descent from the lords of Fontenay, hereditary
+champions of the dukes of Normandy, and held the castle of
+Tamworth, Leicestershire, and the manor of Scrivelsby, Lincolnshire.
+The right to the championship was disputed with the
+Dymoke family by Sir Baldwin de Freville, lord of Tamworth,
+who was descended from an elder daughter of Philip Marmion.
+The court of claims eventually decided in favour of the owners
+of Scrivelsby on the ground that Scrivelsby was held in grand
+serjeanty, that is, that its tenure was dependent on rendering
+a special service, in this case the championship.</p>
+
+<p>Sir Thomas Dymoke (1428?-1471) joined a Lancastrian
+rising in 1469, and, with his brother-in-law Richard, Lord Willoughby
+and Welles, was beheaded in 1471 by order of Edward IV.
+after he had been induced to leave sanctuary on a promise of
+personal safety. The estates were restored to his son Sir Robert
+Dymoke (d. 1546), champion at the coronations of Richard III.,
+Henry VII. and Henry VIII., who distinguished himself at the
+siege of Tournai and became treasurer of the kingdom. His
+descendants acted as champions at successive coronations.
+Lewis Dymoke (d. 1820) put in an unsuccessful claim before the
+House of Lords for the barony of Marmion. His nephew Henry
+(1801-1865) was champion at the coronation of George IV.
+He was accompanied on that occasion by the duke of Wellington
+and Lord Howard of Effingham. Henry Dymoke was created
+a baronet; he was succeeded by his brother John, rector of
+Scrivelsby (1804-1873), whose son Henry Lionel died without
+<span class="pagenum"><a name="page756" id="page756"></a>756</span>
+issue in 1875, when the baronetcy became extinct, the estate
+passing to a collateral branch of the family. After the coronation
+of George IV. the ceremony was allowed to lapse, but at the
+coronation of King Edward VII. H.S. Dymoke bore the standard
+of England in Westminster Abbey.</p>
+
+
+<hr class="art" />
+<p><span class="bold">DYNAMICS<a name="ar5" id="ar5"></a></span> (from Gr. <span class="grk" title="dynamis">&#948;&#973;&#957;&#945;&#956;&#953;&#962;</span>, strength), the name of a branch
+of the science of Mechanics (<i>q.v.</i>). The term was at one time
+restricted to the treatment of motion as affected by force, being
+thus opposed to Statics, which investigated equilibrium or
+conditions of rest. In more recent times the word has been
+applied comprehensively to the action of force on bodies either
+at rest or in motion, thus including &ldquo;dynamics&rdquo; (now termed
+kinetics) in the restricted sense and &ldquo;statics.&rdquo;</p>
+
+<p><span class="sc">Analytical Dynamics.</span>&mdash;The fundamental principles of
+dynamics, and their application to special problems, are explained
+in the articles <span class="sc"><a href="#artlinks">Mechanics</a></span> and <span class="sc"><a href="#artlinks">Motion, Laws of</a></span>, where
+brief indications are also given of the more general methods of
+investigating the properties of a dynamical system, independently
+of the accidents of its particular constitution, which were inaugurated
+by J.L. Lagrange. These methods, in addition to the unity
+and breadth which they have introduced into the treatment
+of pure dynamics, have a peculiar interest in relation to modern
+physical speculation, which finds itself confronted in various
+directions with the problem of explaining on dynamical principles
+the properties of systems whose ultimate mechanism can
+at present only be vaguely conjectured. In determining the
+properties of such systems the methods of analytical geometry
+and of the infinitesimal calculus (or, more generally, of mathematical
+analysis) are necessarily employed; for this reason the
+subject has been named Analytical Dynamics. The following
+article is devoted to an outline of such portions of general dynamical
+theory as seem to be most important from the physical point
+of view.</p>
+
+<div class="condensed">
+<p class="pt2 center">1. <i>General Equations of Impulsive Motion.</i></p>
+
+<p>The systems contemplated by Lagrange are composed of discrete
+particles, or of rigid bodies, in finite number, connected (it may be)
+in various ways by invariable geometrical relations, the fundamental
+postulate being that the position of every particle of the
+system at any time can be completely specified by means of the
+instantaneous values of a finite number of independent variables
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>, each of which admits of continuous variation over a
+certain range, so that if x, y, z be the Cartesian co-ordinates of any
+one particle, we have for example</p>
+
+<p class="center">x = &fnof;(q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>), y = &amp;c., z = &amp;c.,</p>
+<div class="author">(1)</div>
+
+<p class="noind">where the functions &fnof; differ (of course) from particle to particle.
+In modern language, the variables q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span> are <i>generalized co-ordinates</i>
+serving to specify the <i>configuration</i> of the system; their
+derivatives with respect to the time are denoted by q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">n</span>, and
+are called the <i>generalized components of velocity</i>. The continuous
+sequence of configurations assumed by the system in any actual or
+imagined motion (subject to the given connexions) is called the
+<i>path</i>.</p>
+
+<p>For the purposes of a connected outline of the whole subject it
+is convenient to deviate somewhat from the historical order of
+development, and to begin with the consideration of
+<span class="sidenote">Impulsive motion.</span>
+<i>impulsive</i> motion. Whatever the actual motion of the
+system at any instant, we may conceive it to be generated
+instantaneously from rest by the application of proper impulses.
+On this view we have, if x, y, z be the rectangular co-ordinates of any
+particle m,</p>
+
+<p class="center">m&#7819; = X&prime;, m&#7823; = Y&prime;, mz&#729; = Z&prime;,</p>
+<div class="author">(2)</div>
+
+<p class="noind">where X&prime;, Y&prime;, Z&prime; are the components of the impulse on m. Now
+let &delta;x, &delta;y, &delta;z be any infinitesimal variations of x, y, z which are consistent
+with the connexions of the system, and let us form the
+equation</p>
+
+<p class="center">&Sigma;m(&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z) = &Sigma;(X&prime;&delta;x + Y&prime;&delta;y + Z&prime;&delta;z),</p>
+<div class="author">(3)</div>
+
+<p class="noind">where the sign &Sigma; indicates (as throughout this article) a summation
+extending over all the particles of the system. To transform (3)
+into an equation involving the variations &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... of the generalized
+co-ordinates, we have</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7819; =</td> <td>&part;x</td>
+<td rowspan="2">q&#729;<span class="su">1</span> +</td> <td>&part;x</td>
+<td rowspan="2">q&#729;<span class="su">2</span> + ..., &amp;c., &amp;c.</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(4)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&delta;x =</td> <td>&part;x</td>
+<td rowspan="2">&delta;q<span class="su">1</span> +</td> <td>&part;x</td>
+<td rowspan="2">&delta;q<span class="su">2</span> + ..., &amp;c., &amp;c.</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(5)</div>
+
+<p class="noind">and therefore</p>
+
+<p class="center">&Sigma;m(&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z) = A<span class="su">11</span>q&#729;<span class="su">1</span> + A<span class="su">12</span>q&#729;<span class="su">2</span> + ...)&delta;q<span class="su">1</span>
+          + (A<span class="su">21</span>q&#729;<span class="su">1</span> + A<span class="su">22</span>q&#729;<span class="su">2</span> + ...)&delta;q<span class="su">2</span> + ...,</p>
+<div class="author">(6)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">A<span class="su">rr</span> = &Sigma;m <span class="f150">{ (</span></td> <td>&part;x</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2">+ <span class="f150">(</span></td> <td>&part;y</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2">+ <span class="f150">(</span></td> <td>&part;z</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2"><span class="f150">}</span>,</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td>&nbsp;</td>
+<td class="denom">&part;q<span class="su">r</span></td> <td>&nbsp;</td>
+<td class="denom">&part;q<span class="su">r</span></td> <td>&nbsp;</td></tr></table>
+<div class="author">(7)</div>
+
+<table class="math0a" summary="math">
+<tr><td rowspan="2">A<span class="su">rs</span> = &Sigma;m <span class="f150">{</span></td>
+<td>&part;x</td> <td>&part;x</td> <td rowspan="2">+</td>
+<td>&part;y</td> <td>&part;y</td> <td rowspan="2">+</td>
+<td>&part;z</td> <td>&part;z</td> <td rowspan="2"><span class="f150">}</span> = A<span class="su">sr</span>.</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">s</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">s</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">s</span></td></tr></table>
+
+<p class="noind">If we form the expression for the kinetic energy &Tau; of the system,
+we find</p>
+
+<p class="center">2&Tau; = &Sigma;m(&#7819;² + &#7823;² + z&#729;²) = A<span class="su">11</span>q&#729;<span class="su">1</span>² + A<span class="su">22</span>q&#729;<span class="su">2</span>² ... 2A<span class="su">12</span>q&#729;<span class="su">1</span>q&#729;<span class="su">2</span> + ...</p>
+<div class="author">(8)</div>
+
+<p class="noind">The coefficients A<span class="su">11</span>, A<span class="su">22</span>, ... A<span class="su">12</span>, ... are by an obvious analogy called
+the <i>coefficients of inertia</i> of the system; they are in general functions
+of the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>,.... The equation (6) may now be written</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&Sigma;m(&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z) =</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">1</span> +</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">2</span> + ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(9)</div>
+
+<p class="noind">This maybe regarded as the cardinal formula in Lagrange&rsquo;s method.
+For the right-hand side of (3) we may write</p>
+
+<p class="center">&Sigma;(X&prime;&delta;x + Y&prime;&delta;y + Z&prime;&delta;z) = Q&prime;<span class="su">1</span>&delta;q<span class="su">1</span> + Q&prime;<span class="su">2</span>&delta;q<span class="su">2</span> + ... ,</p>
+<div class="author">(10)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q&prime;<span class="su">r</span> = &Sigma;<span class="f150">(</span>X&prime;</td> <td>&part;x</td>
+<td rowspan="2">+ Y&prime;</td> <td>&part;y</td>
+<td rowspan="2">+ Z&prime;</td> <td>&part;z</td>
+<td rowspan="2"><span class="f150">)</span>.</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(11)</div>
+
+<p class="noind">The quantities Q<span class="su">1</span>, Q<span class="su">2</span>, ... are called the <i>generalized components of
+impulse</i>. Comparing (9) and (10), we have, since the variations
+&delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>,... are independent,</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;&Tau;</td> <td rowspan="2"> = Q&prime;<span class="su">1</span>,</td>
+<td>&part;&Tau;</td> <td rowspan="2">= Q&prime;<span class="su">2</span>, ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(12)</div>
+
+<p class="noind">These are the general equations of impulsive motion.</p>
+
+<p>It is now usual to write</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p<span class="su">r</span> =</td> <td>&part;&Tau;</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">r</span></td></tr></table>
+<div class="author">(13)</div>
+
+<p class="noind">The quantities p<span class="su">1</span>, p<span class="su">2</span>, ... represent the effects of the several component
+impulses on the system, and are therefore called the <i>generalized
+components of momentum</i>. In terms of them we have</p>
+
+<p class="center">&Sigma;m(&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z) = p<span class="su">1</span>&delta;q<span class="su">1</span> + p<span class="su">2</span>&delta;q<span class="su">2</span> + ...</p>
+<div class="author">(14)</div>
+
+<p class="noind">Also, since &Tau; is a homogeneous quadratic function of the velocities
+q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span> ...,</p>
+
+<p class="center">2&Tau; = p<span class="su">1</span>q&#729;<span class="su">1</span> + p<span class="su">2</span>q&#729;<span class="su">2</span> + ...</p>
+<div class="author">(15)</div>
+
+<p class="noind">This follows independently from (14), assuming the special variations
+&delta;x = &#7819;dt, &amp;c., and therefore &delta;q<span class="su">1</span> = q&#729;<span class="su">1</span>dt, &delta;q<span class="su">2</span> = q&#729;<span class="su">2</span>dt, ...</p>
+
+<p>Again, if the values of the velocities and the momenta
+<span class="sidenote">Reciprocal theorems.</span>
+in any other motion of the system through the same configuration
+be distinguished by accents, we have the identity</p>
+
+<p class="center">p<span class="su">1</span>q&#729;&prime;<span class="su">1</span> + p<span class="su">2</span>q&#729;&prime;<span class="su">2</span> + ... = p&prime;<span class="su">1</span>q&#729;<span class="su">1</span> + p&prime;<span class="su">2</span>q&#729;<span class="su">2</span> + ...,</p>
+<div class="author">(16)</div>
+
+<p class="noind">each side being equal to the symmetrical expression</p>
+
+<p class="center">A<span class="su">11</span>q&#729;<span class="su">1</span>q&#729;&prime;<span class="su">1</span> + A<span class="su">22</span>q&#729;<span class="su">2</span>q&#729;&prime;<span class="su">2</span> + ... + A<span class="su">12</span>(q&#729;<span class="su">1</span>q&#729;&prime;<span class="su">2</span> + q&#729;&prime;<span class="su">1</span>q&#729;<span class="su">2</span>) + ...</p>
+<div class="author">(17)</div>
+
+<p>The theorem (16) leads to some important reciprocal relations.
+Thus, let us suppose that the momenta p<span class="su">1</span>, p<span class="su">2</span>, ... all vanish with
+the exception of p<span class="su">1</span>, and similarly that the momenta p&prime;<span class="su">1</span>, p&prime;<span class="su">2</span>, ... all
+vanish except p&prime;<span class="su">2</span>. We have then p<span class="su">1</span>q&#729;&prime;<span class="su">1</span> = p&prime;<span class="su">2</span>q&#729;<span class="su">2</span>, or</p>
+
+<p class="center">q&#729;<span class="su">2</span> : p<span class="su">1</span> = q&#729;&prime;<span class="su">1</span> : p&prime;<span class="su">2</span></p>
+<div class="author">(18)</div>
+
+<p class="noind">The interpretation is simplest when the co-ordinates q<span class="su">1</span>, q<span class="su">2</span> are
+both of the same kind, <i>e.g.</i> both lines or both angles. We may
+then conveniently put p<span class="su">1</span> = p&prime;<span class="su">2</span>, and assert that the velocity of the
+first type due to an impulse of the second type is equal to the velocity
+of the second type due to an equal impulse of the first type. As an
+example, suppose we have a chain of straight links hinged each to
+the next, extended in a straight line, and free to move. A blow
+at right angles to the chain, at any point P, will produce a certain
+velocity at any other point Q; the theorem asserts that an equal
+velocity will be produced at P by an equal blow at Q. Again, an
+impulsive couple acting on any link A will produce a certain angular
+velocity in any other link B; an equal couple applied to B will
+produce an equal angular velocity in A. Also if an impulse F applied
+at P produce an angular velocity &omega; in a link A, a couple Fa applied
+to A will produce a linear velocity &omega;a at P. Historically, we may
+note that reciprocal relations in dynamics were first recognized by
+H.L.F. Helmholtz in the domain of acoustics; their use has been
+greatly extended by Lord Rayleigh.</p>
+
+<p>The equations (13) determine the momenta p<span class="su">1</span>, p<span class="su">2</span>,... as linear
+functions of the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>,... Solving these, we can express
+q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span> ... as linear functions of p<span class="su">1</span>, p<span class="su">2</span>,... The resulting
+equations give us the velocities produced by any given
+<span class="sidenote">Velocities in terms of momenta.</span>
+system of impulses. Further, by substitution in (8),
+we can express the kinetic energy as a homogeneous
+quadratic function of the momenta p<span class="su">1</span>, p<span class="su">2</span>,... The kinetic energy,
+<i>as so expressed</i>, will be denoted by &Tau;`; thus</p>
+
+<p class="center">2&Tau;` = A`<span class="su">11</span>p<span class="su">1</span>² + A`<span class="su">22</span>p<span class="su">2</span>² + ... + 2A`<span class="su">12</span>p-p<span class="su">2</span> + ...</p>
+<div class="author">(19)</div>
+
+<p class="noind">where A`<span class="su">11</span>, A`<span class="su">22</span>,... A`<span class="su">12</span>,... are certain coefficients depending on the
+configuration. They have been called by Maxwell the <i>coefficients
+of mobility</i> of the system. When the form (19) is given, the values
+<span class="pagenum"><a name="page757" id="page757"></a>757</span>
+of the velocities in terms of the momenta can be expressed in a remarkable
+form due to Sir W.R. Hamilton. The formula (15) may
+be written</p>
+
+<p class="center">p<span class="su">1</span>q&#729;<span class="su">1</span> + p<span class="su">2</span>q&#729;<span class="su">2</span> + ... = &Tau; + &Tau;`,</p>
+<div class="author">(20)</div>
+
+<p class="noind">where &Tau; is supposed expressed as in (8), and &Tau;` as in (19). Hence
+if, for the moment, we denote by &delta; a variation affecting the velocities,
+and therefore the momenta, but not the configuration, we have</p>
+
+<p class="center">p<span class="su">1</span>&delta;q&#729;<span class="su">1</span> + q&#729;<span class="su">1</span>&delta;p + p<span class="su">2</span>&delta;q&#729;<span class="su">2</span> + q&#729;<span class="su">2</span>&delta;p<span class="su">2</span> + ... = &delta;&Tau; + &delta;&Tau;`</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2"> &emsp;&emsp;&emsp;=</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> +</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">2</span> + ... +</td> <td>&part;&Tau;`</td>
+<td rowspan="2">&delta;p<span class="su">1</span> +</td> <td>&part;&Tau;`</td>
+<td rowspan="2">&delta;p<span class="su">2</span> + ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td>
+<td class="denom">&part;p<span class="su">1</span></td> <td class="denom">&part;p<span class="su">2</span></td></tr></table>
+<div class="author">(21)</div>
+
+<p class="noind">In virtue of (13) this reduces to</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">q&#729;<span class="su">1</span>&delta;p<span class="su">1</span> + q&#729;<span class="su">2</span>&delta;p<span class="su">2</span> + ... =</td> <td>&part;&Tau;`</td>
+<td rowspan="2">&delta;p<span class="su">1</span> +</td> <td>&part;&Tau;`</td>
+<td rowspan="2">&delta;p<span class="su">2</span>  + ...</td></tr>
+<tr><td class="denom">&part;p<span class="su">1</span></td> <td class="denom">&part;p<span class="su">2</span></td></tr></table>
+<div class="author">(22)</div>
+
+<p class="noind">Since &delta;p<span class="su">1</span>, &delta;p<span class="su">2</span>, ... may be taken to be independent, we infer that</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">q&#729;<span class="su">1</span> =</td> <td>&part;&Tau;`</td>
+<td rowspan="2">, &emsp;&emsp; q&#729;<span class="su">2</span> =</td> <td>&part;&Tau;`</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;p<span class="su">1</span></td> <td class="denom">&part;p<span class="su">2</span></td></tr></table>
+<div class="author">(23)</div>
+
+<p class="noind">In the very remarkable exposition of the matter given by James
+Clerk Maxwell in his <i>Electricity and Magnetism</i>, the Hamiltonian
+expressions (23) for the velocities in terms of the impulses are
+obtained directly from first principles, and the formulae (13) are
+then deduced by an inversion of the above argument.</p>
+
+<p>An important modification of the above process was introduced
+by E.J. Routh and Lord Kelvin and P.G. Tait. Instead of expressing
+the kinetic energy in terms of the velocities alone,
+or in terms of the momenta alone, we may express it in
+<span class="sidenote">Routh&rsquo;s modification.</span>
+terms of the velocities corresponding to some of the co-ordinates,
+say q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>, and of the momenta corresponding
+to the remaining co-ordinates, which (for the sake of distinction)
+we may denote by &chi;, &chi;&prime;, &chi;&Prime;, .... Thus, &Tau; being expressed
+as a homogeneous quadratic function of q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ...,
+the momenta corresponding to the co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, ... may be
+written</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&kappa; =</td> <td>&part;&Tau;</td>
+<td rowspan="2">, &emsp; &kappa;&prime; =</td> <td>&part;&Tau;</td>
+<td rowspan="2">, &emsp; &kappa;&Prime; =</td> <td>&part;&Tau;</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;&chi;&#729;</td> <td class="denom">&part;&chi;&#729;&prime;</td>
+<td class="denom">&part;&chi;&#729;&Prime;</td></tr></table>
+<div class="author">(24)</div>
+
+<p class="noind">These equations, when written out in full, determine &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ...
+as linear functions of q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, &kappa;, &kappa;&prime;, &kappa;&Prime;,... We now consider
+the function</p>
+
+<p class="center">R = &Tau; &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; &kappa;&Prime;&chi;&#729;&Prime; &minus; ... ,</p>
+<div class="author">(25)</div>
+
+<p class="noind">supposed expressed, by means of the above relations in terms of
+q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, &kappa;, &kappa;&prime;, &kappa;&Prime;, ... Performing the operation &delta; on both sides
+of (25), we have</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;R</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td> <td>&part;R</td>
+<td rowspan="2">&delta;&kappa; + ... =</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;&chi;&#729; + ... &minus; &kappa;&part;&chi;&#729; &minus; &chi;&#729;&delta;&kappa; &minus; ... ,</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;&kappa;</td>
+<td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;&chi;&#729;</td></tr></table>
+<div class="author">(26)</div>
+
+<p class="noind">where, for brevity, only one term of each type has been exhibited.
+Omitting the terms which cancel in virtue of (24), we have</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;R</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td> <td>&part;R</td>
+<td rowspan="2">&delta;&kappa; + ... =</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... &minus; &chi;&#729;&delta;&kappa; &minus; ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;&kappa;</td>
+<td class="denom">&part;q&#729;<span class="su">1</span></td></tr></table>
+<div class="author">(27)</div>
+
+<p class="noind">Since the variations &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... &delta;q<span class="su">m</span>, &delta;&kappa;, &delta;&kappa;&prime;, &delta;&kappa;&Prime;, ... may be taken to be
+independent, we have</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p<span class="su">1</span> =</td> <td>&part;&Tau;</td>
+<td rowspan="2">=</td> <td>&part;R</td>
+<td rowspan="2">, &emsp; p<span class="su">2</span> =</td> <td>&part;&Tau;</td>
+<td rowspan="2">=</td> <td>&part;R</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">1</span></td>
+<td class="denom">&part;q&#729;<span class="su">2</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(28)</div>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&chi;&#729; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, &emsp; &chi;&#729;&prime; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, &emsp; &chi;&#729;&Prime; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;&kappa;</td> <td class="denom">&part;&kappa;&prime;</td>
+<td class="denom">&part;&kappa;&Prime;</td></tr></table>
+<div class="author">(29)</div>
+
+<p>An important property of the present transformation is that,
+when expressed in terms of the new variables, the kinetic energy is
+the sum of two homogeneous quadratic functions, thus</p>
+
+<p class="center">&Tau; = &#8523; + K,</p>
+<div class="author">(30)</div>
+
+<p class="noind">where &#8523; involves the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span> alone, and K the
+momenta &kappa;, &kappa;&prime;, &kappa;&Prime;, ... alone. For in virtue of (29) we have, from
+(25),</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&Tau; = R &minus; <span class="f150">(</span>&kappa;</td> <td>&part;R</td>
+<td rowspan="2">+ &kappa;&prime;</td> <td>&part;R</td>
+<td rowspan="2">+ &kappa;&Prime;</td> <td>&part;R</td>
+<td rowspan="2">+ ... <span class="f150">)</span>,</td></tr>
+<tr><td class="denom">&part;&kappa;</td> <td class="denom">&part;&kappa;&prime;</td>
+<td class="denom">&part;&kappa;&Prime;</td></tr></table>
+<div class="author">(31)</div>
+
+<p class="noind">and it is evident that the terms in R which are bilinear in respect
+of the two sets of variables q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span> and &kappa;, &kappa;&prime;, &kappa;&Prime;, ... will disappear
+from the right-hand side.</p>
+
+<p>It may be noted that the formula (30) gives immediate proof
+of two important theorems due to Bertrand and to Lord Kelvin
+respectively. Let us suppose, in the first place, that
+the system is started by given impulses of certain types,
+<span class="sidenote">Maximum and minimum energy.</span>
+but is otherwise free. J.L.F. Bertrand&rsquo;s theorem is to
+the effect that the kinetic energy is <i>greater</i> than if by
+impulses of the remaining types the system were constrained
+to take any other course. We may suppose the co-ordinates
+to be so chosen that the constraint is expressed by the vanishing
+of the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, whilst the given impulses are &kappa;, &kappa;&prime;, &kappa;&Prime;,...
+Hence the energy in the actual motion is greater than in the
+constrained motion by the amount &#8523;.</p>
+
+<p>Again, suppose that the system is started with prescribed velocity
+components q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, by means of proper impulses of the corresponding
+types, but is otherwise free, so that in the motion actually
+generated we have &kappa; = 0, &kappa;&prime; = 0, &kappa;&Prime; = 0, ... and therefore K = 0. The
+kinetic energy is therefore <i>less</i> than in any other motion consistent
+with the prescribed velocity-conditions by the value which K
+assumes when &kappa;, &kappa;&prime;, &kappa;&Prime;, ... represent the impulses due to the
+constraints.</p>
+
+<p>Simple illustrations of these theorems are afforded by the chain
+of straight links already employed. Thus if a point of the chain
+be held fixed, or if one or more of the joints be made rigid, the
+energy generated by any given impulses is less than if the chain
+had possessed its former freedom.</p>
+
+<p class="pt2 center">2. <i>Continuous Motion of a System.</i></p>
+
+<p>We may proceed to the continuous motion of a system. The
+<span class="sidenote">Lagrange&rsquo;s equations.</span>
+equations of motion of any particle of the system are of the form</p>
+
+<p class="center">m&#7821; = X, &emsp; mÿ = Y, &emsp; mz¨ = Z</p>
+<div class="author">(1)</div>
+
+<p class="noind">Now let x + &delta;x, y + &delta;y, z + &delta;z be the co-ordinates of m in any
+arbitrary motion of the system differing infinitely little
+from the actual motion, and let us form the equation</p>
+
+<p class="center">&Sigma;m (&#7821;&delta;x + ÿ&delta;y + z¨&delta;z)
+= &Sigma; (X&delta;x + Y&delta;y + Z&delta;z)</p>
+<div class="author">(2)</div>
+
+<p class="noind">Lagrange&rsquo;s investigation consists in the transformation of (2) into
+an equation involving the independent variations &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... &delta;q<span class="su">n</span>.</p>
+
+<p>It is important to notice that the symbols &delta; and d/dt are commutative,
+since</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&delta;&#7819; =</td> <td>d</td>
+<td rowspan="2">(x + &delta;x) &minus;</td> <td>dx</td>
+<td rowspan="2">=</td> <td>d</td>
+<td rowspan="2">&delta;x, &amp;c.</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">dt</td> <td class="denom">dt</td></tr></table>
+<div class="author">(3)</div>
+
+<p class="noind">Hence</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&Sigma;m(&#7821;&delta;x + ÿ&delta;y + z¨&delta;z) =</td> <td>d</td>
+<td rowspan="2">&Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z)
+  &minus; &Sigma;m (&#7819;&delta;&#7819; + &#7823;&delta;&#7823; + z&#729;&delta;z&#729;)</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">=</td> <td>d</td>
+<td rowspan="2">(p<span class="su">1</span>&delta;q<span class="su">1</span> + p<span class="su">2</span>&delta;q<span class="su">2</span> + ...) &minus; &delta;&Tau;,</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(4)</div>
+
+<p class="noind">by § 1 (14). The last member may be written</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">1</span>&delta;q<span class="su">1</span> + p<span class="su">1</span>&delta;q&#729;<span class="su">1</span> + &#7767;<span class="su">2</span>&delta;q<span class="su">2</span> + p<span class="su">2</span>&delta;q&#729;<span class="su">2</span> + ...
+  &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">1</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q&#729;<span class="su">2</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">2</span> &minus; ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q&#729;<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(5)</div>
+
+<p class="noind">Hence, omitting the terms which cancel in virtue of § 1 (13), we
+find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&Sigma;m(&#7821;&delta;x + ÿ&delta;y + z¨&delta;z) = <span class="f150">(</span>&#7767;<span class="su">1</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2"><span class="f150">)</span> &delta;q<span class="su">1</span> + <span class="f150">(</span>&#7767;<span class="su">2</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2"><span class="f150">)</span> &delta;q<span class="su">2</span> + ...</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(6)</div>
+
+<p>For the right-hand side of (2) we have</p>
+
+<p class="center">&Sigma;(X&delta;x + Y&delta;y + Z&delta;z) = Q<span class="su">1</span>&delta;q<span class="su">1</span> + Q<span class="su">2</span>&delta;q<span class="su">2</span>  + ... ,</p>
+<div class="author">(7)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q<span class="su">r</span> = &Sigma; <span class="f150">(</span>X</td> <td>&part;x</td>
+<td rowspan="2">+ Y</td> <td>&part;y</td>
+<td rowspan="2">+ Z</td> <td>&part;z</td>
+<td rowspan="2"><span class="f150">)</span>.</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(8)</div>
+
+<p class="noind">The quantities Q<span class="su">1</span>, Q<span class="su">2</span>, ... are called the <i>generalized components of
+force</i> acting on the system.</p>
+
+<p>Comparing (6) and (7) we find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">1</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">= Q<span class="su">1</span>, &emsp; &#7767;<span class="su">2</span> &minus;</td> <td>&part;&Tau;</td>
+<td rowspan="2">= Q<span class="su">2</span>, ... ,</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(9)</div>
+
+<p class="noind">or, restoring the values of p<span class="su">1</span>, p<span class="su">2</span>, ...,</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2"><span class="f150">(</span></td>
+<td>&part;&Tau;</td> <td rowspan="2"><span class="f150">)</span> &minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= Q<span class="su">1</span>, &emsp;</td>
+<td>d</td> <td rowspan="2"><span class="f150">(</span></td>
+<td>&part;&Tau;</td> <td rowspan="2"><span class="f150">)</span> &minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= Q<span class="su">2</span>, ...</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">1</span></td> <td class="denom">dt</td>
+<td class="denom">&part;q&#729;<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(10)</div>
+
+<p class="noind">These are Lagrange&rsquo;s general equations of motion. Their number
+is of course equal to that of the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... to be determined.</p>
+
+<p>Analytically, the above proof is that given by Lagrange, but
+the terminology employed is of much more recent date, having
+been first introduced by Lord Kelvin and P.G. Tait; it has greatly
+promoted the physical application of the subject. Another proof of
+the equations (10), by direct transformation of co-ordinates, has
+been given by Hamilton and independently by other writers (see
+<span class="sc"><a href="#artlinks">Mechanics</a></span>), but the variational method of Lagrange is that which
+stands in closest relation to the subsequent developments of the
+subject. The chapter of Maxwell, already referred to, is a most
+instructive commentary on the subject from the physical point of
+view, although the proof there attempted of the equations (10) is
+fallacious.</p>
+
+<p>In a &ldquo;conservative system&rdquo; the work which would have to be
+done by extraneous forces to bring the system from rest in some
+standard configuration to rest in the configuration (q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>)
+is independent of the path, and may therefore be regarded as a
+definite function of q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>. Denoting this function (the <i>potential
+energy</i>) by V, we have, if there be no extraneous force on the system,</p>
+
+<p class="center">&Sigma; (X&delta;x + Y&delta;y + Z&delta;z) = &minus; &delta;V,</p>
+<div class="author">(11)</div>
+
+<p class="noind">and therefore</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q<span class="su">1</span> = &minus;</td> <td>&part;V</td>
+<td rowspan="2">, &emsp; Q<span class="su">2</span> = &minus;</td> <td>&part;V</td>
+<td rowspan="2">, ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(12)</div>
+
+<p><span class="pagenum"><a name="page758" id="page758"></a>758</span></p>
+
+<p>Hence the typical Lagrange&rsquo;s equation may be now written in
+the form</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2"><span class="f150">(</span></td>
+<td>&part;&Tau;</td> <td rowspan="2"><span class="f150">)</span> &minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= &minus;</td>
+<td>&part;V</td> <td rowspan="2">,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(13)</div>
+
+<p class="noind">or, again,</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">r</span> = &minus;</td> <td>&part;</td>
+<td rowspan="2">(V &minus; &Tau;).</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(14)</div>
+
+<p class="noind">It has been proposed by Helmholtz to give the name <i>kinetic potential</i>
+to the combination V &minus; &Tau;.</p>
+
+<p>As shown under <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 22, we derive from (10)</p>
+
+<table class="math0" summary="math">
+<tr><td>d&Tau;</td> <td rowspan="2">= Q<span class="su">1</span>q&#729;<span class="su">1</span> + Q<span class="su">2</span>q&#729;<span class="su">2</span> + ... ,</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(15)</div>
+
+<p class="noind">and therefore in the case of a conservative system free from extraneous
+force,</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">(&Tau; + V) = 0 or &Tau; + V = const.,</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(16)</div>
+
+<p class="noind">which is the equation of energy. For examples of the application
+of the formula (13) see <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 22.</p>
+
+<p class="pt2 center">3. <i>Constrained Systems.</i></p>
+
+<p>It has so far been assumed that the geometrical relations, if
+any, which exist between the various parts of the system
+<span class="sidenote">Case of varying relations.</span>
+are of the type § 1 (1), and so do not contain t explicitly.
+The extension of Lagrange&rsquo;s equations to the case of
+&ldquo;varying relations&rdquo; of the type</p>
+
+<p class="center">x = &fnof;(t, q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>), y = &amp;c., z = &amp;c.,</p>
+<div class="author">(1)</div>
+
+<p class="noind">was made by J.M.L. Vieille. We now have</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7819; =</td> <td>&part;x</td>
+<td rowspan="2">+</td> <td>&part;x</td>
+<td rowspan="2">q&#729;<span class="su">1</span> +</td> <td>&part;x</td>
+<td rowspan="2">q&#729;<span class="su">2</span> + ..., &amp;c., &amp;c.,</td></tr>
+<tr><td class="denom">&part;t</td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(2)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&part;x =</td> <td>&part;x</td>
+<td rowspan="2">&delta;q<span class="su">1</span> +</td> <td>&part;x</td>
+<td rowspan="2">&delta;q<span class="su">2</span> + ..., &amp;c., &amp;c.,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(3)</div>
+
+<p class="noind">so that the expression § 1 (8) for the kinetic energy is to be replaced
+by</p>
+
+<p class="center">2&Tau; = &alpha;<span class="su">0</span> + 2&alpha;<span class="su">1</span>q&#729;<span class="su">1</span> + 2&alpha;<span class="su">2</span>q&#729;<span class="su">2</span> + ... + A<span class="su">11</span>q&#729;<span class="su">1</span>² + A<span class="su">22</span>q&#729;<span class="su">2</span>² + ... + A<span class="su">12</span>q&#729;<span class="su">1</span>q&#729;<span class="su">2</span> + ...,</p>
+<div class="author">(4)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&alpha;<span class="su">0</span> = &Sigma;m <span class="f150">{ (</span></td> <td>&part;x</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2">+ <span class="f150">(</span></td> <td>&part;y</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2">+ <span class="f150">(</span></td> <td>&part;z</td>
+<td rowspan="2"><span class="f150">)</span></td> <td>²</td>
+<td rowspan="2"><span class="f150">}</span>,</td></tr>
+<tr><td class="denom">&part;t</td> <td>&nbsp;</td>
+<td class="denom">&part;t</td> <td>&nbsp;</td>
+<td class="denom">&part;t</td> <td>&nbsp;</td></tr></table>
+<div class="author">(5)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&alpha;<span class="su">r</span> = &Sigma;m <span class="f150">{</span></td> <td>&part;x</td>
+<td rowspan="2">&nbsp;</td> <td>&part;x</td>
+<td rowspan="2">+</td> <td>&part;y</td>
+<td rowspan="2">&nbsp;</td> <td>&part;y</td>
+<td rowspan="2">+</td> <td>&part;z</td>
+<td rowspan="2">&nbsp;</td> <td>&part;z</td>
+<td rowspan="2"><span class="f150">}</span>,</td></tr>
+<tr><td class="denom">&part;t</td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;t</td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;t</td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+
+<p class="noind">and the forms of A<span class="su">rr</span>, A<span class="su">rs</span> are as given by § 1 (7). It is to be remembered
+that the coefficients &alpha;<span class="su">0</span>, &alpha;<span class="su">1</span>, &alpha;<span class="su">2</span>, ... A<span class="su">11</span>, A<span class="su">22</span>, ... A<span class="su">12</span> ... will in
+general involve t explicitly as well as implicitly through the co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>,.... Again, we find</p>
+
+<p class="center">&Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z) = (&alpha;<span class="su">1</span> + A<span class="su">11</span>q&#729;<span class="su">1</span> + A<span class="su">12</span>q&#729;<span class="su">2</span> + ...) &delta;q<span class="su">1</span>
+    + (&alpha;<span class="su">2</span> + A<span class="su">21</span>q&#729;<span class="su">1</span> + A<span class="su">22</span>q&#729;<span class="su">2</span> + ...) &part;q<span class="su">2</span> + ...</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">=</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">1</span> +</td> <td>&part;&Tau;</td>
+<td rowspan="2">&delta;q<span class="su">2</span> + ...
+  = p<span class="su">1</span>&delta;q<span class="su">1</span> + p<span class="su">2</span>&delta;q<span class="su">2</span> + ...,</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(6)</div>
+
+<p class="noind">where p<span class="su">r</span> is defined as in § 1 (13). The derivation of Lagrange&rsquo;s
+equations then follows exactly as before. It is to be noted that
+the equation § 2 (15) does not as a rule now hold. The proof involved
+the assumption that &Tau; is a homogeneous quadratic function
+of the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>....</p>
+
+<p>It has been pointed out by R.B. Hayward that Vieille&rsquo;s case can
+be brought under Lagrange&rsquo;s by introducing a new co-ordinate (&chi;)
+in place of t, so far as it appears explicitly in the relations (1). We
+have then</p>
+
+<p class="center">2&Tau; = &alpha;<span class="su">0</span>&chi;&#729;² + 2(&alpha;<span class="su">1</span>q&#729;<span class="su">1</span> + &alpha;<span class="su">2</span>q&#729;<span class="su">2</span> + ...) &chi;&#729; + A<span class="su">11</span>q&#729;<span class="su">1</span>² + A<span class="su">22</span>q&#729;<span class="su">2</span>² + ... + 2A<span class="su">12</span>q&#729;<span class="su">1</span>q&#729;<span class="su">2</span> + ....</p>
+<div class="author">(7)</div>
+
+<p class="noind">The equations of motion will be as in § 2 (10), with the additional
+equation</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">&minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= X,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;&chi;&#729;</td>
+<td class="denom">&part;&chi;</td></tr></table>
+<div class="author">(8)</div>
+
+<p class="noind">where X is the force corresponding to the co-ordinate &chi;. We may
+suppose X to be adjusted so as to make &chi;¨ = 0, and in the remaining
+equations nothing is altered if we write t for &chi; before, instead of
+after, the differentiations. The reason why the equation § 2 (15)
+no longer holds is that we should require to add a term X&chi;&#729; on the
+right-hand side; this represents the rate at which work is being
+done by the constraining forces required to keep &chi;&#729; constant.</p>
+
+<p>As an example, let x, y, z be the co-ordinates of a particle relative
+to axes fixed in a solid which is free to rotate about the axis of z.
+If &phi; be the angular co-ordinate of the solid, we find without difficulty</p>
+
+<p class="center">2&Tau; = m (&#7819;² + &#7823;² +z&#729;²) + 2&phi;&#729;m (x&#7823; &minus; y&#7819;) + {I + m (x² + y²)} &phi;&#729;²,</p>
+<div class="author">(9)</div>
+
+<p class="noind">where I is the moment of inertia of the solid. The equations of
+motion, viz.</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">&minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= X, &emsp;</td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">&minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= Y, &emsp;</td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">&minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= Z,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;&#7819;</td>
+<td class="denom">&part;x</td> <td class="denom">dt</td>
+<td class="denom">&part;&#7823;</td> <td class="denom">&part;y</td>
+<td class="denom">dt</td> <td class="denom">&part;z&#729;</td>
+<td class="denom">&part;z</td></tr></table>
+<div class="author">(10)</div>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">&minus;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= &Phi;,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;&phi;&#729;</td>
+<td class="denom">&part;&phi;</td></tr></table>
+<div class="author">(11)</div>
+
+<p class="noind">become</p>
+
+<p class="center">m (&#7821; &minus; 2&phi;&#729;&#7823; &minus; x&phi;&#729;² &minus; y&phi;¨) = X, m (ÿ + 2&phi;&#729;&#7819; &minus; y&phi;&#729;² + x&phi;¨) = Y, mz¨ = Z,</p>
+<div class="author">(12)</div>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">[{I + m (x² + y²)} &phi;&#729; + m (x&#7823; &minus; y&#7819;)] = &Phi;.</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(13)</div>
+
+<p class="noind">If we suppose &Phi; adjusted so as to maintain &phi;¨ = 0, or (again) if we
+suppose the moment of inertia I to be infinitely great, we obtain
+the familiar equations of motion relative to moving axes, viz.</p>
+
+<p class="center">m (&#7821; &minus; 2&omega;&#7823; &minus; &omega;²x) = X, m (ÿ + 2&omega;&#7819; &minus; &omega;²y) = Y, mz¨ = Z,</p>
+<div class="author">(14)</div>
+
+<p class="noind">where &omega; has been written for &phi;. These are the equations which
+we should have obtained by applying Lagrange&rsquo;s rule at once to
+the formula</p>
+
+<p class="center">2&Tau; = m (&#7819;² + &#7823;² + z&#729;²) + 2m&omega; (x&#7823; &minus; y&#7819;) + m&omega;² (x² + y²),</p>
+<div class="author">(15)</div>
+
+<p class="noind">which gives the kinetic energy of the particle referred to axes rotating
+with the constant angular velocity &omega;. (See <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 13.)</p>
+
+<p>More generally, let us suppose that we have a certain group of
+co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, ... whose absolute values do not affect the
+expression for the kinetic energy, and that by suitable forces of the
+corresponding types the velocity-components &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ... are maintained
+constant. The remaining co-ordinates being denoted by
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>, we may write</p>
+
+<p class="center">2T = &#8523; + T<span class="su">0</span> + 2(&alpha;<span class="su">1</span>q&#729;<span class="su">1</span> + &alpha;<span class="su">2</span>q&#729;<span class="su">2</span> + ...) &chi;&#729; + 2(&alpha;&prime;<span class="su">1</span>q&#729;<span class="su">1</span> + &alpha;&prime;<span class="su">2</span>q&#729;<span class="su">2</span> + ...) &chi;&#729;&prime; + ...,</p>
+<div class="author">(16)</div>
+
+<p class="noind">where &#8523; is a homogeneous quadratic function of the velocities
+q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">n</span> of the type § 1 (8), whilst &Tau;<span class="su">0</span> is a homogeneous quadratic
+function of the velocities &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ... alone. The remaining terms,
+which are bilinear in respect of the two sets of velocities, are indicated
+more fully. The formulae (10) of § 2 give n equations of
+the type</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2"><span class="f150">(</span></td>
+<td>&part;&#8523;</td> <td rowspan="2"><span class="f150">)</span> &minus;</td>
+<td>&part;&#8523;</td> <td rowspan="2">+ (r, 1) q&#729;<span class="su">1</span> + (r, 2) q&#729;<span class="su">2</span> + ... &minus;</td>
+<td>&part;T<span class="su">0</span></td> <td rowspan="2">= Q<span class="su">r</span></td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(17)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">(r, s) = <span class="f150">(</span></td> <td>&part;&alpha;<span class="su">r</span></td>
+<td rowspan="2">&minus;</td> <td>&part;&alpha;<span class="su">s</span></td>
+<td rowspan="2"><span class="f150">)</span>&chi;&#729; + <span class="f150">(</span></td> <td>&part;&alpha;&prime;<span class="su">r</span></td>
+<td rowspan="2">&minus;</td> <td>&part;&alpha;&prime;<span class="su">s</span></td>
+<td rowspan="2"><span class="f150">)</span>&chi;&#729;&prime; + ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">s</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">s</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(18)</div>
+
+<p class="noind">These quantities (r, s) are subject to the relations</p>
+
+<p class="center">(r, s) = &minus;(s, r), (r, r) = 0</p>
+<div class="author">(19)</div>
+
+<p class="noind">The remaining dynamical equations, equal in number to the co-ordinates
+&chi;, &chi;&prime;, &chi;&Prime;, ..., yield expressions for the forces which
+must be applied in order to maintain the velocities &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ...
+constant; they need not be written down. If we follow the method
+by which the equation of energy was established in § 2, the equations
+(17) lead, on taking account of the relations (19), to</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">(&#8523; &minus; T<span class="su">0</span>) = Q<span class="su">1</span>q&#729;<span class="su">1</span> + Q<span class="su">2</span>q&#729;<span class="su">2</span> + ... + Q<span class="su">n</span>q&#729;<span class="su">n</span>,</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(20)</div>
+
+<p class="noind">or, in case the forces Q<span class="su">r</span> depend only on the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>
+and are conservative,</p>
+
+<p class="center">&#8523; + V &minus; T<span class="su">0</span> = const.</p>
+<div class="author">(21)</div>
+
+<p>The conditions that the equations (17) should be satisfied by zero
+values of the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">n</span>
+are</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q<span class="su">r</span> = &minus;</td> <td>&part;T<span class="su">0</span></td>
+<td rowspan="2">,</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(22)</div>
+
+<p class="noind">or in the case of conservative forces</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;</td> <td rowspan="2">(V &minus; T<span class="su">0</span>) = 0,</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(23)</div>
+
+<p class="noind"><i>i.e.</i> the value of V &minus; &Tau;<span class="su">0</span> must be <i>stationary</i>.</p>
+
+<p>We may apply this to the case of a system whose configuration
+relative to axes rotating with constant angular velocity (&omega;)
+is defined by means of the n co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>.
+<span class="sidenote">Rotating axes.</span>
+This is important on account of its bearing on the kinetic
+theory of the tides. Since the Cartesian co-ordinates
+x, y, z of any particle m of the system relative to the moving axes
+are functions of q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>, of the form § 1 (1), we have, by (15)</p>
+
+<p class="center">2&#8523; = &Sigma;m (&#7819;² + &#7823;² + z&#729;²), &emsp; 2&Tau;<span class="su">0</span> = &omega;²&Sigma;m (x² + y²),</p>
+<div class="author">(24)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&alpha;<span class="su">r</span> = &Sigma;m <span class="f150">(</span>x</td> <td>&part;y</td>
+<td rowspan="2">&minus; y</td> <td>&part;x</td>
+<td rowspan="2"><span class="f150">)</span>,</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(25)</div>
+
+<p class="noind">whence</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">(r, s) = 2&omega;·&Sigma;m</td> <td>&part;(x, y)</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">&part;(q<span class="su">s</span>, q<span class="su">r</span>)</td></tr></table>
+<div class="author">(26)</div>
+
+<p class="noind">The conditions of relative equilibrium are given by (23).</p>
+
+<p>It will be noticed that this expression V &minus; T<span class="su">0</span>, which is to be
+stationary, differs from the true potential energy by a term which
+represents the potential energy of the system in relation to fictitious
+&ldquo;centrifugal forces.&rdquo; The question of stability of relative equilibrium
+will be noticed later (§ 6).</p>
+
+<p>It should be observed that the remarkable formula (20) may in
+the present case be obtained directly as follows. From (15) and
+(14) we find</p>
+
+<table class="math0" summary="math">
+<tr><td>dT</td> <td rowspan="2">=</td>
+<td>d</td> <td rowspan="2">(&#8523; + T<span class="su">0</span>) + &omega;·&Sigma;m (xÿ &minus; y&#7821;) =</td>
+<td>d</td> <td rowspan="2">(&#8523; &minus; T<span class="su">0</span>) + &omega;·&Sigma; (xY &minus; yX).</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">dt</td>
+<td class="denom">dt</td></tr></table>
+<div class="author">(27)</div>
+
+<p><span class="pagenum"><a name="page759" id="page759"></a>759</span></p>
+
+<p class="noind">This must be equal to the rate at which the forces acting on the
+system do work, viz. to</p>
+
+<p class="center">&omega;&Sigma; (xY &minus; yX) + Q<span class="su">1</span>q&#729;<span class="su">1</span> + Q<span class="su">2</span>q&#729;<span class="su">2</span> + ... + Q<span class="su">n</span>q&#729;<span class="su">n</span>,</p>
+
+<p class="noind">where the first term represents the work done in virtue of the
+rotation.</p>
+
+<p>We have still to notice the modifications which Lagrange&rsquo;s
+equations undergo when the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>
+<span class="sidenote">Constrained systems.</span>
+are not all independently variable. In the first place,
+we may suppose them connected by a number m (&lt; n)
+of relations of the type</p>
+
+<p class="center">A (t, q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>) = 0, &emsp; B (t, q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>) = 0, &amp;c.</p>
+<div class="author">(28)</div>
+
+<p class="noind">These may be interpreted as introducing partial constraints into
+a previously free system. The variations &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... &delta;q<span class="su">n</span> in the expressions
+(6) and (7) of § 2 which are to be equated are no longer
+independent, but are subject to the relations</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;A</td> <td rowspan="2">&delta;q<span class="su">1</span> +</td>
+<td>&part;A</td> <td rowspan="2">&delta;q<span class="su">2</span> + ... = 0, &emsp;</td>
+<td>&part;B</td> <td rowspan="2">&delta;q<span class="su">1</span> +</td>
+<td>&part;B</td> <td rowspan="2">&delta;q<span class="su">2</span> + ... = 0, &amp;c.</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td>
+<td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(29)</div>
+
+<p class="noind">Introducing indeterminate multipliers &lambda;, &mu;, ..., one for each of these
+equations, we obtain in the usual manner n equations of the type</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;T</td> <td rowspan="2">&minus;</td>
+<td>&part;T</td> <td rowspan="2">= Q<span class="su">r</span> + &lambda;</td>
+<td>&part;A</td> <td rowspan="2">+ &mu;</td>
+<td>&part;B</td> <td rowspan="2">+ ...,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom"> &part;q<span class="su">r</span></td></tr></table>
+<div class="author">(30)</div>
+
+<p class="noind">in place of § 2 (10). These equations, together with (28), serve
+to determine the n co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span> and the m multipliers
+&lambda;, &mu;, ....</p>
+
+<p>When t does not occur explicitly in the relations (28) the system
+is said to be <i>holonomic</i>. The term connotes the existence of integral
+(as opposed to differential) relations between the co-ordinates,
+independent of the time.</p>
+
+<p>Again, it may happen that although there are no prescribed
+relations between the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>, yet from the circumstances
+of the problem certain geometrical conditions are imposed
+on their <i>variations</i>, thus</p>
+
+<p class="center">A<span class="su">1</span>&delta;q<span class="su">1</span> + A<span class="su">2</span>&delta;q<span class="su">2</span> + ... = 0, &emsp; B<span class="su">1</span>&delta;q<span class="su">1</span> + B<span class="su">2</span>&delta;q<span class="su">2</span> + ... = 0, &amp;c.,</p>
+<div class="author">(31)</div>
+
+<p class="noind">where the coefficients are functions of q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span> and (possibly) of t.
+It is assumed that these equations are not integrable as regards the
+variables q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>; otherwise, we fall back on the previous conditions.
+Cases of the present type arise, for instance, in ordinary
+dynamics when we have a solid rolling on a (fixed or moving) surface.
+The six co-ordinates which serve to specify the position of the solid
+at any instant are not subject to any necessary relation, but the
+conditions to be satisfied at the point of contact impose three conditions
+of the form (31). The general equations of motion are
+obtained, as before, by the method of indeterminate multipliers,
+thus</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;T</td> <td rowspan="2">&minus;</td>
+<td>&part;T</td> <td rowspan="2">= Q<span class="su">r</span> + &lambda;A<span class="su">r</span> + &mu;B<span class="su">r</span> + ...</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(32)</div>
+
+<p class="noind">The co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">n</span>, and the indeterminate multipliers
+&lambda;, &mu;, ..., are determined by these equations and by the velocity-conditions
+corresponding to (31). When t does not appear explicitly
+in the coefficients, these velocity-conditions take the forms</p>
+
+<p class="center">A<span class="su">1</span>q&#729;<span class="su">1</span> + A<span class="su">2</span>q&#729;<span class="su">2</span> + ... = 0, &emsp; B<span class="su">1</span>q&#729;<span class="su">1</span> + B<span class="su">2</span>q&#729;<span class="su">2</span> + ... = 0, &amp;c.</p>
+<div class="author">(33)</div>
+
+<p class="noind">Systems of this kind, where the relations (31) are not integrable, are
+called <i>non-holonomic</i>.</p>
+
+<p class="pt2 center">4. <i>Hamiltonian Equations of Motion.</i></p>
+
+<p>In the Hamiltonian form of the equations of motion of a conservative
+system with unvarying relations, the kinetic energy is
+supposed expressed in terms of the momenta p<span class="su">1</span>, p<span class="su">2</span>, ... and the co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ..., as in § 1 (19). Since the symbol &delta; now denotes
+a variation extending to the co-ordinates as well as to the momenta,
+we must add to the last member of § 1 (21) terms of the types</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;T</td> <td rowspan="2">&delta;q<span class="su">1</span> +</td>
+<td>&part;T`</td> <td rowspan="2">&delta;q<span class="su">2</span> + ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(1)</div>
+
+<p class="noind">Since the variations &delta;p<span class="su">1</span>, &delta;p<span class="su">2</span>, ... &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... may be taken to be independent,
+we infer the equations § 1 (23) as before, together with</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;T</td> <td rowspan="2">= &minus;</td>
+<td>&part;T`</td> <td rowspan="2">, &emsp; </td>
+<td>&part;T</td> <td rowspan="2">= &minus;</td>
+<td>&part;T`</td> <td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(2)</div>
+
+<p class="noind">Hence the Lagrangian equations § 2 (14) transform into</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">1</span> = &minus;</td> <td>&part;</td>
+<td rowspan="2">(T` + V), &emsp; &#7767;<span class="su">2</span> = &minus;</td> <td>&part;</td>
+<td rowspan="2">(T` + V), ...</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(3)</div>
+
+<p class="noind">If we write</p>
+
+<p class="center">H = T` + V,</p>
+<div class="author">(4)</div>
+
+<p class="noind">so that H denotes the <i>total energy</i> of the system, supposed expressed
+in terms of the new variables, we get</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">1</span> = &minus;</td> <td>&part;H</td>
+<td rowspan="2">, &emsp; &#7767;<span class="su">2</span> = &minus;</td> <td>&part;H</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(5)</div>
+
+<p class="noind">If to these we join the equations</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">q&#729;<span class="su">1</span> =</td> <td>&part;H</td>
+<td rowspan="2">, &emsp; q&#729;<span class="su">2</span> =</td> <td>&part;H</td>
+<td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;p<span class="su">1</span></td> <td class="denom">&part;p<span class="su">2</span></td></tr></table>
+<div class="author">(6)</div>
+
+<p class="noind">which follow at once from § 1 (23), since V does not involve p<span class="su">1</span>, p<span class="su">2</span>, ...,
+we obtain a complete system of differential equations <i>of the first
+order</i> for the determination of the motion.</p>
+
+<p>The equation of energy is verified immediately by (5) and (6),
+since these make</p>
+
+<table class="math0" summary="math">
+<tr><td>dH</td> <td rowspan="2">=</td>
+<td>&part;H</td> <td rowspan="2">&#7767;<span class="su">1</span> +</td>
+<td>&part;H</td> <td rowspan="2">&#7767;<span class="su">2</span> + ... +</td>
+<td>&part;H</td> <td rowspan="2">q&#729;<span class="su">1</span> +</td>
+<td>&part;H</td> <td rowspan="2">q&#729;<span class="su">2</span> + ... = 0.</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;p<span class="su">1</span></td>
+<td class="denom">&part;p<span class="su">2</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(7)</div>
+
+<p>The Hamiltonian transformation is extended to the case of
+varying relations as follows. Instead of (4) we write</p>
+
+<p class="center">H = p<span class="su">1</span>q&#729;<span class="su">1</span> + p<span class="su">2</span>q&#729;<span class="su">2</span> + ... &minus; T + V,</p>
+<div class="author">(8)</div>
+
+<p class="noind">and imagine H to be expressed in terms of the momenta p<span class="su">1</span>, p<span class="su">2</span>, ...,
+the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ..., and the time. The internal forces of
+the system are assumed to be conservative, with the potential
+energy V. Performing the variation &delta; on both sides, we find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&delta;H = q&#729;<span class="su">1</span>&delta;p<span class="su">1</span> + ... &minus;</td> <td>&part;T</td>
+<td rowspan="2">&delta;q<span class="su">1</span> +</td> <td>&part;V</td>
+<td rowspan="2">&delta;q + ...,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td></tr></table>
+<div class="author">(9)</div>
+
+<p class="noind">terms which cancel in virtue of the definition of p<span class="su">1</span>, p<span class="su">2</span>, ... being
+omitted. Since &delta;p<span class="su">1</span>, &delta;p<span class="su">2</span>, ..., &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... may be taken to be independent,
+we infer</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">q&#729;<span class="su">1</span> =</td> <td>&part;H</td>
+<td rowspan="2">, &emsp; q&#729;<span class="su">2</span> =</td> <td>&part;H</td>
+<td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;p<span class="su">1</span></td> <td class="denom">&part;p<span class="su">2</span></td></tr></table>
+<div class="author">(10)</div>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;</td> <td rowspan="2">(T &minus; V) = &minus;</td>
+<td>&part;H</td> <td rowspan="2">, &emsp;</td>
+<td>&part;</td> <td rowspan="2">(T &minus; V) = &minus;</td>
+<td>&part;H</td> <td rowspan="2">, ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(11)</div>
+
+<p class="noind">It follows from (11) that</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&#7767;<span class="su">1</span> = &minus;</td> <td>&part;H</td>
+<td rowspan="2">, &emsp; &#7767;<span class="su">2</span> = &minus;</td> <td>&part;H</td>
+<td rowspan="2">, ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(12)</div>
+
+<p class="noind">The equations (10) and (12) have the same form as above, but H
+is no longer equal to the energy of the system.</p>
+
+<p class="pt2 center">5. <i>Cyclic Systems.</i></p>
+
+<p>A <i>cyclic</i> or <i>gyrostatic</i> system is characterized by the following
+properties. In the first place, the kinetic energy is not affected if
+we alter the absolute values of certain of the co-ordinates, which
+we will denote by &chi;, &chi;&prime;, &chi;&Prime;, ..., provided the remaining co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span> and the velocities, including of course the velocities
+&chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ..., are unaltered. Secondly, there are no forces acting
+on the system of the types &chi;, &chi;&prime;, &chi;&Prime;, .... This case arises, for example,
+when the system includes gyrostats which are free to rotate about
+their axes, the co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, ... then being the angular co-ordinates
+of the gyrostats relatively to their frames. Again, in
+theoretical hydrodynamics we have the problem of moving solids
+in a frictionless liquid; the ignored co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, ... then refer
+to the fluid, and are infinite in number. The same question presents
+itself in various physical speculations where certain phenomena are
+ascribed to the existence of <i>latent motions</i> in the ultimate constituents
+of matter. The general theory of such systems has been treated by
+E.J. Routh, Lord Kelvin, and H.L.F. Helmholtz.</p>
+
+<p>If we suppose the kinetic energy &Tau; to be expressed, as in
+Lagrange&rsquo;s method, in terms of the co-ordinates and
+<span class="sidenote">Routh&rsquo;s equations.</span>
+the velocities, the equations of motion corresponding
+to &chi;, &chi;&prime;, &chi;&Prime;, ... reduce, in virtue of the above hypotheses,
+to the forms</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= 0, &emsp; </td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= 0, &emsp; </td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= 0, ...,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;&chi;&#729;</td>
+<td class="denom">dt</td> <td class="denom">&part;&chi;&#729;&prime;</td>
+<td class="denom">dt</td> <td class="denom">&part;&chi;&#729;&Prime;</td></tr></table>
+<div class="author">(1)</div>
+
+<p class="noind">whence</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;&Tau;</td> <td rowspan="2">= &kappa;, &emsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= &kappa;&prime;, &emsp;</td>
+<td>&part;&Tau;</td> <td rowspan="2">= &kappa;&Prime;, ...,</td></tr>
+<tr><td class="denom">&part;&chi;&#729;</td> <td class="denom">&part;&chi;&#729;&prime;</td>
+<td class="denom">&part;&chi;&#729;&Prime;</td></tr></table>
+<div class="author">(2)</div>
+
+<p class="noind">where &kappa;, &kappa;&prime;, &kappa;&Prime;, ... are the constant momenta corresponding to the
+cyclic co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, .... These equations are linear in
+&chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;, ...; solving them with respect to these quantities and
+substituting in the remaining Lagrangian equations, we obtain
+m differential equations to determine the remaining co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>. The object of the present investigation is to ascertain
+the general form of the resulting equations. The retained co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span> may be called (for distinction) the <i>palpable</i>
+co-ordinates of the system; in many practical questions they are
+the only co-ordinates directly in evidence.</p>
+
+<p>If, as in § 1 (25), we write</p>
+
+<p class="center">R = T &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; &kappa;&Prime;&chi;&#729;&Prime; &minus; ...,</p>
+<div class="author">(3)</div>
+
+<p class="noind">and imagine R to be expressed by means of (2) as a quadratic function
+of q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, &kappa;, &kappa;&prime;, &kappa;&Prime;, ... with coefficients which are in general
+functions of the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>, then, performing the
+operation &delta; on both sides, we find</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;R</td> <td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td>
+<td>&part;R</td> <td rowspan="2">&delta;&kappa; + ... +</td>
+<td>&part;R</td> <td rowspan="2">&delta;q<span class="su">1</span> + ... =</td>
+<td>&part;T</td> <td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td>
+<td>&part;T</td> <td rowspan="2">&delta;q<span class="su">1</span> + ...</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;&kappa;</td>
+<td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">1</span></td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">+</td> <td>&part;T</td>
+<td rowspan="2">&delta;&chi;&#729; + ... +</td> <td>&part;T</td>
+<td rowspan="2">&delta;q<span class="su">1</span> + ... &minus; &kappa;&delta;&chi;&#729; &minus; &chi;&#729;&delta;&kappa; &minus; ....</td></tr>
+<tr><td class="denom">&part;&chi;&#729;</td> <td class="denom">&part;&chi;<span class="su">1</span></td></tr></table>
+<div class="author">(4)</div>
+
+<p><span class="pagenum"><a name="page760" id="page760"></a>760</span></p>
+
+<p class="noind">Omitting the terms which cancel by (2), we find</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;T</td> <td rowspan="2">=</td>
+<td>&part;R</td> <td rowspan="2">, &emsp; </td>
+<td>&part;T</td> <td rowspan="2">=</td>
+<td>&part;R</td> <td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q&#729;<span class="su">1</span></td>
+<td class="denom">&part;q&#729;<span class="su">2</span></td> <td class="denom">&part;q&#729;<span class="su">2</span></td></tr></table>
+<div class="author">(5)</div>
+
+<table class="math0" summary="math">
+<tr><td>&part;T</td> <td rowspan="2">=</td>
+<td>&part;R</td> <td rowspan="2">, &emsp; </td>
+<td>&part;T</td> <td rowspan="2">=</td>
+<td>&part;R</td> <td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(6)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&chi;&#729; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, &emsp; &chi;&#729;&prime; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, &emsp; &chi;&#729;&Prime; = &minus;</td> <td>&part;R</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;&kappa;</td> <td class="denom">&part;&kappa;&prime;</td>
+<td class="denom">&part;&kappa;&Prime;</td></tr></table>
+<div class="author">(7)</div>
+
+<p>Substituting in § 2 (10), we have</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;R</td> <td rowspan="2">&minus;</td>
+<td>&part;R</td> <td rowspan="2">= Q<span class="su">1</span>, &emsp; </td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;R</td> <td rowspan="2">&minus;</td>
+<td>&part;R</td> <td rowspan="2">= Q<span class="su">2</span>, ...</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">1</span></td> <td class="denom">dt</td>
+<td class="denom">&part;q&#729;<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(8)</div>
+
+<p class="noind">These are Routh&rsquo;s forms of the modified Lagrangian equations.
+Equivalent forms were obtained independently by Helmholtz at a
+later date.</p>
+
+<p>The function R is made up of three parts, thus</p>
+
+<p class="center">R = R<span class="su">2, 0</span> + R<span class="su">1, 1</span> + R<span class="su">0, 2</span>, ...</p>
+<div class="author">(9)</div>
+
+<p>where R<span class="su">2, 0</span> is a homogeneous quadratic function of q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>, R<span class="su">0, 2</span> is
+<span class="sidenote">Kelvin&rsquo;s equations.</span>
+a homogeneous quadratic function of &kappa;, &kappa;&prime;, &kappa;&Prime;, ..., whilst
+R<span class="su">1, 1</span> consists of products of the velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span> into
+the momenta &kappa;, &kappa;&prime;, &kappa;&Prime;.... Hence from (3) and (7) we
+have</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">T = R &minus; <span class="f150">(</span>&kappa;</td> <td>&part;R</td>
+<td rowspan="2">+ &kappa;&prime;</td> <td>&part;R</td>
+<td rowspan="2">+ &kappa;&Prime;</td> <td>&part;R</td>
+<td rowspan="2">+ ...<span class="f150">)</span> = R<span class="su">2, 0</span> &minus; R<span class="su">0, 2</span>.</td></tr>
+<tr><td class="denom">&part;&kappa;</td> <td class="denom">&part;&kappa;&prime;</td>
+<td class="denom">&part;&kappa;&Prime;</td></tr></table>
+<div class="author">(10)</div>
+
+<p>If, as in § 1 (30), we write this in the form</p>
+
+<p class="center">&Tau; = &#8523; + K,</p>
+<div class="author">(11)</div>
+
+<p class="noind">then (3) may be written</p>
+
+<p class="center">R = &#8523; &minus; K + &beta;<span class="su">1</span>q&#729;<span class="su">1</span> + &beta;<span class="su">2</span>q&#729;<span class="su">2</span> + ...,</p>
+<div class="author">(12)</div>
+
+<p class="noind">where &beta;<span class="su">1</span>, &beta;<span class="su">2</span>, ... are linear functions of &kappa;, &kappa;&prime;, &kappa;&Prime;, ..., say</p>
+
+<p class="center">&beta;<span class="su">r</span> = &alpha;<span class="su">r</span>&kappa; + &alpha;&prime;<span class="su">r</span>&kappa;&prime; + &alpha;&Prime;<span class="su">r</span>&kappa;&Prime; + ...,</p>
+<div class="author">(13)</div>
+
+<p class="noind">the coefficients &alpha;<span class="su">r</span>, &alpha;&prime;<span class="su">r</span>, &alpha;&Prime;<span class="su">r</span>, ... being in general functions of the co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>. Evidently &beta;<span class="su">r</span> denotes that part of the momentum-component
+&part;R / &part;q&#729;<span class="su">r</span> which is due to the cyclic motions. Now</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;R</td> <td rowspan="2">=</td>
+<td>d</td> <td rowspan="2"><span class="f150">(</span></td>
+<td>&part;&#8523;</td> <td rowspan="2">+ &beta;<span class="su">r</span><span class="f150">)</span> =</td>
+<td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&#8523;</td> <td rowspan="2">+</td>
+<td>&part;&beta;<span class="su">r</span></td> <td rowspan="2">q&#729;<span class="su">1</span> +</td>
+<td>&part;&beta;<span class="su">r</span></td> <td rowspan="2">q&#729;<span class="su">2</span>+ ...,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(14)</div>
+
+<table class="math0" summary="math">
+<tr><td>&part;R</td> <td rowspan="2">=</td>
+<td>&part;&#8523;</td> <td rowspan="2">&minus;</td>
+<td>&part;K</td> <td rowspan="2">+</td>
+<td>&part;&beta;<span class="su">1</span></td> <td rowspan="2">q&#729;<span class="su">1</span> +</td>
+<td>&part;&beta;<span class="su">2</span></td> <td rowspan="2">q&#729;<span class="su">2</span> + ....</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(15)</div>
+
+<p class="noind">Hence, substituting in (8), we obtain the typical equation of motion
+of a gyrostatic system in the form</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&#8523;</td> <td rowspan="2">&minus;</td>
+<td>&part;&#8523;</td> <td rowspan="2">+ (r, 1) q&#729;<span class="su">1</span> + (r, 2) q&#729;<span class="su">2</span> + ... + (r, s) q&#729;<span class="su">s</span> + ... +</td>
+<td>&part;K</td> <td rowspan="2">= Q<span class="su">r</span>,</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(16)</div>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">(r, s) =</td> <td>&part;&beta;<span class="su">r</span></td>
+<td rowspan="2">&minus;</td> <td>&part;&beta;<span class="su">s</span></td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">&part;q<span class="su">s</span></td> <td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(17)</div>
+
+<p>This form is due to Lord Kelvin. When q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span> have been
+determined, as functions of the time, the velocities corresponding
+to the cyclic co-ordinates can be found, if required, from the relations
+(7), which may be written</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&chi;&#729; =</td> <td>&part;K</td>
+<td rowspan="2">&minus; &alpha;<span class="su">1</span>q&#729;<span class="su">1</span>  &minus; &alpha;<span class="su">2</span>q&#729;<span class="su">2</span>  &minus; ...,</td></tr>
+<tr><td class="denom">&part;&kappa;</td></tr></table>
+<div class="author">(18)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&chi;&#729;&prime; =</td> <td>&part;K</td>
+<td rowspan="2">&minus; &alpha;&prime;<span class="su">1</span>q&#729;<span class="su">1</span> &minus; &alpha;&prime;<span class="su">2</span>q&#729;<span class="su">2</span> &minus; ...,</td></tr>
+<tr><td class="denom">&part;&kappa;&prime;</td></tr></table>
+
+<p class="center">&amp;c., &amp;c.</p>
+
+<p>It is to be particularly noticed that</p>
+
+<p class="center">(r, r) = 0, (r, s) = &minus;(s, r).</p>
+<div class="author">(19)</div>
+
+<p class="noind">Hence, if in (16) we put r = 1, 2, 3, ... m, and multiply by q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ... q&#729;<span class="su">m</span>
+respectively, and add, we find</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">(&#8523; + K) = Q<span class="su">1</span>q&#729;<span class="su">1</span> + Q<span class="su">2</span>q&#729;<span class="su">2</span> + ...,</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(20)</div>
+
+<p class="noind">or, in the case of a conservative system</p>
+
+<p class="center">&#8523; + V + K = const.,</p>
+<div class="author">(21)</div>
+
+<p class="noind">which is the equation of energy.</p>
+
+<p>The equation (16) includes § 3 (17) as a particular case, the
+eliminated co-ordinate being the angular co-ordinate of a rotating
+solid having an infinite moment of inertia.</p>
+
+<p>In the particular case where the cyclic momenta &kappa;, &kappa;&prime;, &kappa;&Prime;, ... are
+all zero, (16) reduces to</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&nbsp;</td>
+<td>&part;&#8523;</td> <td rowspan="2">&minus;</td>
+<td>&part;&#8523;</td> <td rowspan="2">= Q<span class="su">r</span>.</td></tr>
+<tr><td class="denom">dt</td> <td class="denom">&part;q&#729;<span class="su">r</span></td>
+<td class="denom">&part;q<span class="su">r</span></td></tr></table>
+<div class="author">(22)</div>
+
+<p class="noind">The form is the same as in § 2, and the system now behaves, as
+regards the co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>, exactly like the acyclic type
+there contemplated. These co-ordinates do not, however, now
+fix the position of every particle of the system. For example, if
+by suitable forces the system be brought back to its initial configuration
+(so far as this is defined by q<span class="su">1</span>, q<span class="su">2</span>, ..., q<span class="su">m</span>), after performing
+any evolutions, the ignored co-ordinates &chi;, &chi;&prime;, &chi;&Prime;, ... will not in
+general return to their original values.</p>
+
+<p>If in Lagrange&rsquo;s equations § 2 (10) we reverse the sign of the time-element
+dt, the equations are unaltered. The motion is therefore
+reversible; that is to say, if as the system is passing through any
+configuration its velocities q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ..., q&#729;<span class="su">m</span> be all reversed, it will (if the
+forces be the same in the same configuration) retrace its former
+path. But it is important to observe that the statement does not
+in general hold of a gyrostatic system; the terms of (16), which are
+linear in q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ..., q&#729;<span class="su">m</span>, change sign with dt, whilst the others do not.
+Hence the motion of a gyrostatic system is not reversible, unless
+indeed we reverse the cyclic motions as well as the velocities
+q&#729;<span class="su">1</span>, q&#729;<span class="su">2</span>, ..., q&#729;<span class="su">m</span>. For instance, the precessional motion of a top cannot
+be reversed unless we reverse the spin.</p>
+
+<p>The <i>conditions of equilibrium</i> of a system with latent cyclic motions
+<span class="sidenote">Kineto-statics.</span>
+are obtained by putting q&#729;<span class="su">1</span> = 0, q&#729;<span class="su">2</span> = 0, ... q&#729;<span class="su">m</span> = 0  in (16);
+viz. they are</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q<span class="su">1</span> =</td> <td>&part;K</td>
+<td rowspan="2">, &emsp; Q<span class="su">2</span> =</td> <td>&part;K</td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(23)</div>
+
+<p class="noind">These may of course be obtained independently. Thus if the system
+be guided from (apparent) rest in the configuration (q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>)
+to rest in the configuration q<span class="su">1</span> + &delta;q<span class="su">1</span>, q<span class="su">2</span> + &delta;q<span class="su">2</span>, ..., q<span class="su">m</span> + &delta;q<span class="su">m</span>, the work
+done by the forces must be equal to the increment of the kinetic
+energy. Hence</p>
+
+<p class="center">Q<span class="su">1</span>&delta;q<span class="su">1</span> + Q<span class="su">2</span>&delta;q<span class="su">2</span> + ... = &delta;K,</p>
+<div class="author">(24)</div>
+
+<p class="noind">which is equivalent to (23). The conditions are the same as for
+the equilibrium of a system without latent motion, but endowed
+with potential energy K. This is important from a physical point
+of view, as showing how energy which is apparently potential may
+in its ultimate essence be kinetic.</p>
+
+<p>By means of the formulae (18), which now reduce to</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&chi;&#729; =</td> <td>&part;K</td>
+<td rowspan="2">, &emsp; &chi;&#729;&prime; =</td> <td>&part;K</td>
+<td rowspan="2">, &emsp; &chi;&#729;&Prime; =</td> <td>&part;K</td>
+<td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;&kappa;</td> <td class="denom">&part;&kappa;&prime;</td>
+<td class="denom">&part;&kappa;&Prime;</td></tr></table>
+<div class="author">(25)</div>
+
+<p class="noind">K may also be expressed as a homogeneous quadratic function of
+the cyclic velocities &chi;&#729;, &chi;&#729;&prime;, &chi;&#729;&Prime;,... Denoting it in this form by &Tau;<span class="su">0</span>,
+we have</p>
+
+<p class="center">&delta; (T<span class="su">0</span> + K) = 2&delta;K = &delta; (&kappa;&chi;&#729; + &kappa;&prime;&chi;&#729;&prime; + &kappa;&Prime;&chi;&#729;&Prime; +  ...)</p>
+<div class="author">(26)</div>
+
+<p class="noind">Performing the variations, and omitting the terms which cancel by
+(2) and (25), we find</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;&Tau;<span class="su">0</span></td> <td rowspan="2">= &minus;</td>
+<td>&part;K</td> <td rowspan="2">, &emsp; </td>
+<td>&part;&Tau;<span class="su">0</span></td> <td rowspan="2">= &minus;</td>
+<td>&part;K</td> <td rowspan="2">, ...,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(27)</div>
+
+<p class="noind">so that the formulae (23) become</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Q<span class="su">1</span> = &minus;</td> <td>&part;&Tau;<span class="su">0</span></td>
+<td rowspan="2">, &emsp; Q<span class="su">2</span> = &minus;</td> <td>&part;&Tau;<span class="su">0</span></td>
+<td rowspan="2">, ...</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(28)</div>
+
+<p>A simple example is furnished by the top (<span class="sc"><a href="#artlinks">Mechanics</a></span>, § 22). The
+cyclic co-ordinates being &psi;, &phi;, we find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">2&#8523; = A&theta;&#729;², &emsp; 2K =</td> <td>(&mu; &minus; &nu; cos &theta;)²</td>
+<td rowspan="2">+</td> <td>&nu;²</td>
+<td rowspan="2">,</td></tr>
+<tr><td class="denom">A sin² &theta;</td> <td class="denom">C</td></tr></table>
+
+<p class="center">2&Tau;<span class="su">0</span> = A sin² &theta;&psi;&#729;² + C (&phi;&#729; + &psi; cos &theta;)²,</p>
+<div class="author">(29)</div>
+
+<p class="noind">whence we may verify that &part;&Tau;<span class="su">0</span> / &part;&theta; = &minus;&part;K / &part;&theta; in accordance with
+(27). And the condition of equilibrium</p>
+
+<table class="math0" summary="math">
+<tr><td>&part;K</td> <td rowspan="2">= &minus;</td>
+<td>&part;V</td></tr>
+<tr><td class="denom">&part;&theta;</td> <td class="denom">&part;&theta;</td></tr></table>
+<div class="author">(30)</div>
+
+<p class="noind">gives the condition of steady precession.</p>
+
+<p class="pt2 center">6. <i>Stability of Steady Motion.</i></p>
+
+<p>The small oscillations of a conservative system about a configuration
+of equilibrium, and the criterion of stability, are discussed
+in <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 23. The question of the stability of given types of
+motion is more difficult, owing to the want of a sufficiently general,
+and at the same time precise, definition of what we mean by
+&ldquo;stability.&rdquo; A number of definitions which have been propounded by
+different writers are examined by F. Klein and A. Sommerfeld in their
+work <i>Über die Theorie des Kreisels</i> (1897-1903). Rejecting previous
+definitions, they base their criterion of stability on the character
+of the changes produced in the <i>path</i> of the system by small arbitrary
+disturbing impulses. If the undisturbed path be the <i>limiting form</i>
+of the disturbed path when the impulses are indefinitely diminished,
+it is said to be stable, but not otherwise. For instance, the vertical
+fall of a particle under gravity is reckoned as stable, although for a
+<i>given</i> impulsive disturbance, however small, the deviation of the
+particle&rsquo;s position at any time t from the position which it would have
+occupied in the original motion increases indefinitely with t. Even
+this criterion, as the writers quoted themselves recognize, is not free
+from ambiguity unless the phrase &ldquo;limiting form,&rdquo; as applied to a
+path, be strictly defined. It appears, moreover, that a definition
+which is analytically precise may not in all cases be easy to reconcile
+with geometrical prepossessions. Thus a particle moving in a circle
+about a centre of force varying inversely as the cube of the distance
+will if slightly disturbed either fall into the centre, or recede to infinity,
+after describing in either case a spiral with an infinite number of
+<span class="pagenum"><a name="page761" id="page761"></a>761</span>
+convolutions. Each of these spirals has, analytically, the circle as
+its limiting form, although the motion in the circle is most naturally
+described as unstable.</p>
+
+<p>A special form of the problem, of great interest, presents itself in
+the steady motion of a gyrostatic system, when the non-eliminated
+co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span> all vanish (see § 5). This has been discussed
+by Routh, Lord Kelvin and Tait, and Poincaré. These
+writers treat the question, by an extension of Lagrange&rsquo;s method,
+as a problem of small oscillations. Whether we adopt the notion
+of stability which this implies, or take up the position of Klein and
+Sommerfeld, there is no difficulty in showing that stability is ensured
+if V + K be a minimum as regards variations of q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>. The
+proof is the same as that of Dirichlet for the case of statical stability.</p>
+
+<p>We can illustrate this condition from the case of the top, where,
+in our previous notation,</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">V + K = Mgh cos &theta; +</td> <td>(&mu; &minus; &nu;cos &theta;)²</td>
+<td rowspan="2">+</td> <td>&nu;²</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">2A sin² &theta;</td> <td class="denom">2C</td></tr></table>
+<div class="author">(1)</div>
+
+<p class="noind">To examine whether the steady motion with the centre of gravity
+vertically above the pivot is stable, we must put &mu; = &nu;. We then
+find without difficulty that V + K is a minimum provided &nu;² &ge; 4AMgh.
+The method of small oscillations gave us the condition &nu;² &gt; 4AMgh,
+and indicated instability in the cases &nu;² &le; 4AMgh. The present
+criterion can also be applied to show that the steady precessional
+motions in which the axis has a constant inclination to the vertical
+are stable.</p>
+
+<p>The question remains, as before, whether it is <i>essential</i> for stability
+that V + K should be a minimum. It appears that from the point
+of view of the theory of small oscillations it is not essential, and
+that there may even be stability when V + K is a maximum. The
+precise conditions, which are of a somewhat elaborate character,
+have been formulated by Routh. An important distinction has,
+however, been established by Thomson and Tait, and by Poincaré,
+between what we may call <i>ordinary</i> or <i>temporary</i> stability (which
+is stability in the above sense) and <i>permanent</i> or <i>secular</i> stability,
+which means stability when regard is had to possible dissipative
+forces called into play whenever the co-ordinates q<span class="su">1</span>,  q<span class="su">2</span>, ... q<span class="su">m</span> vary.
+Since the total energy of the system at any instant is given (in
+the notation of § 5) by an expression of the form &#8523; + V + K, where
+&#8523; cannot be negative, the argument of Thomson and Tait, given
+under <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 23, for the statical question, shows that it is a
+necessary as well as a sufficient condition for secular stability that
+V + K should be a minimum. When a system is &ldquo;ordinarily&rdquo;
+stable, but &ldquo;secularly&rdquo; unstable, the operation of the frictional
+forces is to induce a gradual increase in the amplitude of the free
+vibrations which are called into play by accidental disturbances.</p>
+
+<p>There is a similar theory in relation to the constrained systems
+considered in § 3 above. The equation (21) there given leads to
+the conclusion that for secular stability of any type of motion in
+which the velocities q&#729;<span class="su">1</span>,  q&#729;<span class="su">2</span>, ... q&#729;<span class="su">n</span> are zero it is necessary and sufficient
+that the function V &minus; &Tau;<span class="su">0</span> should be a minimum.</p>
+
+<p>The simplest possible example of this is the case of a particle at
+the lowest point of a smooth spherical bowl which rotates with
+constant angular velocity (&omega;) about the vertical diameter. This
+position obviously possesses &ldquo;ordinary&rdquo; stability. If a be the
+radius of the bowl, and &theta; denote angular distance from the lowest
+point, we have</p>
+
+<p class="center">V &minus; &Tau;<span class="su">0</span> = mga(1 &minus; cos &theta;) &minus; ½m&omega;²a² sin² &theta;;</p>
+<div class="author">(2)</div>
+
+<p class="noind">this is a minimum for &theta; = 0 only so long as &omega;² &lt; g/a. For greater
+values of &omega; the only position of &ldquo;permanent&rdquo; stability is that in
+which the particle rotates with the bowl at an angular distance
+cos<span class="sp">&minus;1</span> (g/&omega;²a) from the lowest point. To examine the motion in the
+neighbourhood of the lowest point, when frictional forces are taken
+into account, we may take fixed ones, in a horizontal plane, through
+the lowest point. Assuming that the friction varies as the relative
+velocity, we have</p>
+
+<p class="center">
+&#7821; = &minus;p²x &minus; k (&#7819; + &omega;y),<br />
+ÿ = &minus;p²y &minus; k (&#7823; &minus; &omega;x),</p>
+<div class="author">(3)</div>
+
+<p class="noind">where p² = g/a. These combine into</p>
+
+<p class="center">z¨ + kz&#729; + (p² &minus; ik&omega;) z = 0,</p>
+<div class="author">(4)</div>
+
+<p class="noind">where z = x + iy, i = &radic;&minus;1.  Assuming z = Ce<span class="sp">&lambda;t</span>, we find</p>
+
+<p class="center">&lambda; = &minus;½k(1 &#8723; &omega;/p) ± ip,</p>
+<div class="author">(5)</div>
+
+<p class="noind">if the square of k be neglected. The complete solution is then</p>
+
+<p class="center">x + iy = C<span class="su">1</span>e<span class="sp">&minus;&beta;1t</span> e<span class="sp">ipt</span> +
+ + C<span class="su">2</span>e<span class="sp">&minus;&beta;2t</span> e<span class="sp">&minus;ipt</span>,</p>
+<div class="author">(6)</div>
+
+<p class="noind">where</p>
+
+<p class="center">&beta;<span class="su">1</span> = ½k (1 &minus; &omega;/p), &emsp; &beta;<span class="su">2</span> = ½k (1 + &omega;/p).</p>
+<div class="author">(7)</div>
+
+<p class="noind">This represents two superposed circular vibrations, in opposite
+directions, of period 2&pi;/p. If &omega; &lt; p, the amplitude of each of these
+diminishes asymptotically to zero, and the position x = 0, y = 0 is
+permanently stable. But if &omega; &gt; p the amplitude of that circular
+vibration which agrees in sense with the rotation &omega; will continually
+increase, and the particle will work its way in an ever-widening
+spiral path towards the eccentric position of secular stability. If
+the bowl be not spherical but ellipsoidal, the vertical diameter being
+a principal axis, it may easily be shown that the lowest position is
+permanently stable only so long as the period of the rotation is
+longer than that of the slower of the two normal modes in the
+absence of rotation (see <span class="sc"><a href="#artlinks">Mechanics</a></span>, § 13).</p>
+
+<p class="pt2 center">7. <i>Principle of Least Action.</i></p>
+
+<p>The preceding theories give us statements applicable to the system
+at any one instant of its motion. We now come to a series of
+theorems relating to the whole motion of the system
+between any two configurations through which it passes,
+<span class="sidenote">Stationary Action.</span>
+viz. we consider the actual motion and compare it with
+other imaginable motions, differing infinitely little from it, between
+the same two configurations. We use the symbol &delta; to denote the
+transition from the actual to any one of the hypothetical motions.</p>
+
+<p>The best-known theorem of this class is that of <i>Least Action</i>,
+originated by P.L.M. de Maupertuis, but first put in a definite form
+by Lagrange. The &ldquo;action&rdquo; of a single particle in passing from
+one position to another is the space-integral of the momentum, or
+the time-integral of the <i>vis viva</i>. The action of a dynamical system
+is the sum of the actions of its constituent particles, and is accordingly
+given by the formula</p>
+
+<p class="center">A = &Sigma; <span class="f150">&int;</span> mvds = &Sigma; <span class="f150">&int;</span> mv²dt = 2 <span class="f150">&int;</span> &Tau;dt.</p>
+<div class="author">(1)</div>
+
+<p class="noind">The theorem referred to asserts that the free motion of a conservative
+system between any two given configurations is characterized
+by the property</p>
+
+<p class="center">&delta;A = 0,</p>
+<div class="author">(2)</div>
+
+<p class="noind">provided the total energy have the same constant value in the
+varied motion as in the actual motion.</p>
+
+<p>If t, t&prime; be the times of passing through the initial and final configurations
+respectively, we have</p>
+
+<p class="center">&delta;A = &delta; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ &Sigma;m (&#7819;² + &#7823;² + z&#729;²) dt</p>
+
+<p class="center">= <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> &delta;&Tau;dt + 2&Tau;&prime;&delta;t&prime; + 2&Tau;&delta;t,</p>
+<div class="author">(3)</div>
+
+<p class="noind">since the upper and lower limits of the integral must both be regarded
+as variable. This may be written</p>
+
+<p class="center">&delta;A = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> &delta;&Tau;dt +
+ <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> &Sigma;m (&#7819;&delta;&#7819; + &#7823;&delta;&#7823; + z&#729;&delta;z&#729;) dt + 2&Tau;&prime;&delta;t&prime; &minus; 2&Tau;&delta;t</p>
+
+<p class="center">= <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> &delta;&Tau;dt + <span class="f150">[</span> &Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z)<span class="f150">]</span><span class="sp1">t&prime;</span><span class="su2">t</span></p>
+
+<p class="center">&minus; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> &Sigma;m (&#7821;&delta;x + ÿ&delta;y + z¨&delta;z) dt + 2&Tau;&prime;&delta;t&prime; &minus; 2&Tau;&delta;t.</p>
+<div class="author">(4)</div>
+
+<p class="noind">Now, by d&rsquo;Alembert&rsquo;s principle,</p>
+
+<p class="center">&Sigma;m (&#7821;&delta;x + ÿ&delta;y + z¨&delta;z) = &minus;&delta;V,</p>
+<div class="author">(5)</div>
+
+<p class="noind">and by hypothesis we have</p>
+
+<p class="center">&delta;(&Tau; + V) = 0.</p>
+<div class="author">(6)</div>
+
+<p class="noind">The formula therefore reduces to</p>
+
+<p class="center">&delta;A = <span class="f150">[</span>&Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z)<span class="f150">]</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ + 2&Tau;&prime;&delta;t&prime; &minus; 2&Tau;&delta;t.</p>
+<div class="author">(7)</div>
+
+<p class="noind">Since the terminal configurations are unaltered, we must have at
+the lower limit</p>
+
+<p class="center">&delta;x + &#7819;&delta;t = 0, &emsp; &delta;y + &#7823;&delta;t = 0, &emsp; &delta;z + z&#729;&delta;t = 0,</p>
+<div class="author">(8)</div>
+
+<p class="noind">with similar relations at the upper limit. These reduce (7) to the
+form (2).</p>
+
+<p>The equation (2), it is to be noticed, merely expresses that the
+variation of A vanishes <i>to the first order</i>; the phrase <i>stationary
+action</i> has therefore been suggested as indicating more accurately
+what has been proved. The action in the free path between two
+given configurations is in fact not invariably a minimum, and even
+when a minimum it need not be the <i>least possible</i> subject to the
+given conditions. Simple illustrations are furnished by the case
+of a single particle. A particle moving on a smooth surface, and
+free from extraneous force, will have its velocity constant; hence
+the theorem in this case resolves itself into</p>
+
+<p class="center">&delta; <span class="f150">&int;</span> ds = 0,</p>
+<div class="author">(9)</div>
+
+<p class="noind"><i>i.e.</i> the path must be a geodesic line. Now a geodesic is not necessarily
+the <i>shortest</i> path between two given points on it; for example,
+on the sphere a great-circle arc ceases to be the shortest
+path between its extremities when it exceeds 180°. More generally,
+taking any surface, let a point P, starting from O, move along
+a geodesic; this geodesic will be a minimum path from O to P until
+P passes through a point O&prime; (if such exist), which is the intersection
+with a consecutive geodesic through O. After this point the minimum
+property ceases. On an anticlastic surface two geodesics
+cannot intersect more than once, and each geodesic is therefore a
+minimum path between any two of its points. These illustrations
+are due to K.G.J. Jacobi, who has also formulated the general
+criterion, applicable to all dynamical systems, as follows:&mdash;Let
+O and P denote any two configurations on a natural path of the
+system. If this be the sole free path from O to P with the prescribed
+amount of energy, the action from O to P is a minimum. But if
+<span class="pagenum"><a name="page762" id="page762"></a>762</span>
+there be several distinct paths, let P vary from coincidence with O
+along the first-named path; the action will then cease to be a
+minimum when a configuration O&prime; is reached such that two of the
+possible paths from O to O&prime; coincide. For instance, if O and P be
+positions on the parabolic path of a projectile under gravity, there
+will be a second path (with the same energy and therefore the same
+velocity of projection from O), these two paths coinciding when
+P is at the other extremity (O&prime;, say) of the focal chord through O.
+The action from O to P will therefore be a minimum for all positions
+of P short of O&prime;. Two configurations such as O and O&prime; in the
+general statement are called conjugate <i>kinetic foci</i>. Cf. <span class="sc"><a href="#artlinks">Variations,
+Calculus of</a></span>.</p>
+
+<p>Before leaving this topic the connexion of the principle of
+stationary action with a well-known theorem of optics may be
+noticed. For the motion of a particle in a conservative field of
+force the principle takes the form</p>
+
+<p class="center">&delta; <span class="f150">&int;</span> vds = 0.</p>
+<div class="author">(10)</div>
+
+<p class="noind">On the corpuscular theory of light v is proportional to the refractive
+index &mu; of the medium, whence</p>
+
+<p class="center">&delta; <span class="f150">&int;</span> &mu;ds = 0.</p>
+<div class="author">(11)</div>
+
+<p>In the formula (2) the energy in the hypothetical motion is prescribed,
+whilst the time of transit from the initial to the final configuration
+<span class="sidenote">Hamiltonian principle.</span>
+is variable. In another and generally more
+convenient theorem, due to Hamilton, the time of transit
+is prescribed to be the same as in the actual motion, whilst
+the energy may be different and need not (indeed) be
+constant. Under these conditions we have</p>
+
+<p class="center">&delta; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (T &minus; V)dt = 0,</p>
+<div class="author">(12)</div>
+
+<p class="noind">where t, t&prime; are the prescribed times of passing through the given
+initial and final configurations. The proof of (12) is simple; we
+have</p>
+
+<p class="center">&delta; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ (T &minus; V)dt = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (&delta;&Tau; &minus; &delta;V)dt =
+ <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> {&Sigma;m (&#7819;&delta;&#7819; + &#7823;&delta;&#7823; + z&#729;&delta;z&#729;) &minus; &delta;V} dt</p>
+
+<p class="center">= <span class="f150">[</span> &Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z)<span class="f150">]</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ &minus; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ {&Sigma;m (&#7821;&delta;x + ÿ&delta;y + z¨&delta;z) + &delta;V} dt.</p>
+<div class="author">(13)</div>
+
+<p class="noind">The integrated terms vanish at both limits, since by hypothesis
+the configurations at these instants are fixed; and the terms under
+the integral sign vanish by d&rsquo;Alembert&rsquo;s principle.</p>
+
+<p>The fact that in (12) the variation does not affect the time of
+transit renders the formula easy of application in any system of
+co-ordinates. Thus, to deduce Lagrange&rsquo;s equations, we have</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2"><span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+ (&delta;&Tau; &minus; &delta;V) dt = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> <span class="f150">{</span></td> <td>&part;T </td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> +</td> <td>&part;T</td>
+<td rowspan="2">&delta;q<span class="su">1</span> + ... &minus;</td> <td>&part;V</td>
+<td rowspan="2">&delta;q<span class="su">1</span> &minus; ... <span class="f150">}</span> dt</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">1</span></td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">= <span class="f150">[</span>p<span class="su">1</span>&delta;q<span class="su">1</span> + p<span class="su">2</span>&delta;q<span class="su">2</span> + ...<span class="f150">]</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+  &minus; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> <span class="f150">{ [</span>&#7767;<span class="su">1</span> &minus;</td> <td>&part;T </td>
+<td rowspan="2">+</td> <td>&part;V</td>
+<td rowspan="2"><span class="f150">)</span> &delta;q<span class="su">1</span> + <span class="f150">(</span>&#7767;<span class="su">2</span> &minus;</td> <td>&part;T</td>
+<td rowspan="2">+</td> <td>&part;V</td>
+<td rowspan="2"><span class="f150">)</span> &delta;q<span class="su">2</span> + ...<span class="f150">}</span> dt.</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td>
+<td class="denom">&part;q<span class="su">2</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+<div class="author">(14)</div>
+
+<p class="noind">The integrated terms vanish at both limits; and in order that the
+remainder of the right-hand member may vanish it is necessary
+that the coefficients of &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... under the integral sign should
+vanish for all values of t, since the variations in question are independent,
+and subject only to the condition of vanishing at the
+limits of integration. We are thus led to Lagrange&rsquo;s equation of
+motion for a conservative system. It appears that the formula
+(12) is a convenient as well as a compact embodiment of the whole
+of ordinary dynamics.</p>
+
+<p>The modification of the Hamiltonian principle appropriate to
+<span class="sidenote">Extension to cyclic systems.</span>
+the case of cyclic systems has been given by J. Larmor.
+If we write, as in § 1 (25),</p>
+
+<p class="center">R = &Tau; &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; &kappa;&Prime;&chi;&#729;&Prime; &minus; ...,</p>
+<div class="author">(15)</div>
+
+<p class="noind">we shall have</p>
+
+<p class="center">&delta; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (R &minus; V) dt = 0,</p>
+<div class="author">(16)</div>
+
+<p class="noind">provided that the variation does not affect the cyclic momenta
+&kappa;, &kappa;&prime;, &kappa;&Prime;, ..., and that the configurations at times t and t&prime; are unaltered,
+so far as they depend on the palpable co-ordinates
+q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>. The initial and final values of the ignored co-ordinates
+will in general be affected.</p>
+
+<p>To prove (16) we have, on the above understandings,</p>
+
+<p class="center">&delta; <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (R &minus; V) dt =
+  <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (&delta;T &minus; &kappa;&delta;&chi;&#729; &minus; ... &minus; &delta;V) dt</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">= <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> <span class="f150">(</span></td> <td>&part;T</td>
+<td rowspan="2">&delta;q&#729;<span class="su">1</span> + ... +</td> <td>&part;T</td>
+<td rowspan="2">&delta;q<span class="su">1</span> + ... &minus; &delta;V<span class="f150">)</span> dt,</td></tr>
+<tr><td class="denom">&part;q&#729;<span class="su">1</span></td> <td class="denom">&part;q<span class="su">1</span></td></tr></table>
+<div class="author">(17)</div>
+
+<p class="noind">where terms have been cancelled in virtue of § 5 (2). The last
+member of (17) represents a variation of the integral</p>
+
+<p class="center"><span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (T &minus; V) dt</p>
+
+<p class="noind">on the supposition that &delta;X = 0, &delta;X&prime; = 0, &delta;X&Prime; = 0, ... throughout, whilst
+&delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, &delta;q<span class="su">m</span> vanish at times t and t&prime;; <i>i.e.</i> it is a variation in which
+the initial and final configurations are absolutely unaltered. It
+therefore vanishes as a consequence of the Hamiltonian principle
+in its original form.</p>
+
+<p>Larmor has also given the corresponding form of the principle
+of least action. He shows that if we write</p>
+
+<p class="center">A = <span class="f150">&int;</span> (2T &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; &kappa;&Prime;&chi;&#729;&Prime; &minus; ...) dt,</p>
+<div class="author">(18)</div>
+
+<p class="noind">then</p>
+
+<p class="center">&delta;A = 0,</p>
+<div class="author">(19)</div>
+
+<p class="noind">provided the varied motion takes place with the same constant
+value of the energy, and with the same constant cyclic momenta,
+between the same two configurations, these being regarded as
+defined by the palpable co-ordinates alone.</p>
+
+<p class="pt2 center">§ 8. <i>Hamilton&rsquo;s Principal and Characteristic Functions.</i></p>
+
+<p>In the investigations next to be described a more extended
+meaning is given to the symbol &delta;. We will, in the first
+instance, denote by it an infinitesimal variation of the most
+<span class="sidenote">Principal function.</span>
+general kind, affecting not merely the values of the co-ordinates
+at any instant, but also the initial and final configurations
+and the times of passing through them. If we put</p>
+
+<p class="center">S = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (&Tau; &minus; V) dt,</p>
+<div class="author">(1)</div>
+
+<p class="noind">we have, then,</p>
+
+<p class="center">&delta;S = (T&prime; &minus; V&prime;) &delta;t&prime; &minus; (T &minus; V) &delta;t +
+  <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span> (&delta;&Tau; &minus; &delta;V) dt</p>
+
+<p class="center">= (T&prime; &minus; V&prime;) &delta;t&prime; &minus; (T &minus; V) &delta;t + <span class="f150">[</span>&Sigma;m
+  (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z)<span class="f150">]</span><span class="sp1">t&prime;</span><span class="su2">t</span>.</p>
+<div class="author">(2)</div>
+
+<p>Let us now denote by x&prime; + &delta;x&prime;, y&prime; + &delta;y&prime;, z&prime; + &delta;z&prime;, the final co-ordinates
+(<i>i.e.</i> at time t&prime; + &delta;t&prime;) of a particle m. In the terms in (2) which relate
+to the upper limit we must therefore write &delta;x&prime; &minus; &#7819;&prime;&delta;t&prime;, &delta;y&prime; &minus; &#7823;&prime;&delta;t&prime;,
+&delta;z&prime; &minus; z&#729;&prime;&delta;t&prime; for &delta;x, &delta;y, &delta;z. With a similar modification at the lower
+limit, we obtain</p>
+
+<p class="center">&delta;S = &minus;H&delta;&tau; + &Sigma;m (&#7819;&prime;&delta;x&prime; + &#7823;&prime;&delta;y&prime; + z&#729;&prime;&delta;z&prime;)
+&minus; &Sigma;m (&#7819;&delta;x + &#7823;&delta;y + z&#729;&delta;z),</p>
+<div class="author">(3)</div>
+
+<p class="noind">where H (= T + V) is the constant value of the energy in the free
+motion of the system, and &tau; (= t&prime; &minus; t) is the time of transit. In
+generalized co-ordinates this takes the form</p>
+
+<p class="center">&delta;S = &minus;H&delta;&tau; + p&prime;<span class="su">1</span>&delta;q&prime;<span class="su">1</span> + p&prime;<span class="su">2</span>&delta;q&prime;<span class="su">2</span> + ...
+ &minus; p<span class="su">1</span>&delta;q<span class="su">1</span> &minus; p<span class="su">2</span>&delta;q<span class="su">2</span> &minus; ....</p>
+<div class="author">(4)</div>
+
+<p class="noind">Now if we select any two arbitrary configurations as initial and
+final, it is evident that we can in general (by suitable initial velocities
+or impulses) start the system so that it will of itself pass from the
+first to the second in any prescribed time &tau;. On this view of the
+matter, S will be a function of the initial and final co-ordinates
+(q<span class="su">1</span>, q<span class="su">2</span>, ... and q&prime;<span class="su">1</span>, q&prime;<span class="su">2</span>, ...) and the time &tau;, as independent variables.
+And we obtain at once from (4)</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p&prime;<span class="su">1</span> =</td> <td>&part;S</td>
+<td rowspan="2">, &emsp; p&prime;<span class="su">2</span> =</td> <td>&part;S</td>
+<td rowspan="2">, ... ,</td></tr>
+<tr><td class="denom">&part;q&prime;<span class="su">1</span></td> <td class="denom">&part;q&prime;<span class="su">2</span></td></tr></table>
+<div class="author">(5)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p<span class="su">1</span> = &minus;</td> <td>&part;S</td>
+<td rowspan="2">, &emsp; p<span class="su">2</span> = &minus;</td> <td>&part;S</td>
+<td rowspan="2">, ... ,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">H = &minus;</td> <td>&part;S</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">&part;&tau;</td></tr></table>
+<div class="author">(6)</div>
+
+<p class="noind">S is called by Hamilton the <i>principal function</i>; if its general form
+for any system can be found, the preceding equations suffice to
+determine the motion resulting from any given conditions. If we
+substitute the values of p<span class="su">1</span>, p<span class="su">2</span>, ... and H from (5) and (6) in the expression
+for the kinetic energy in the form T&prime; (see § 1), the equation</p>
+
+<p class="center">T¹ + V = H</p>
+<div class="author">(7)</div>
+
+<p class="noind">becomes a partial differential equation to be satisfied by S. It has
+been shown by Jacobi that the dynamical problem resolves itself
+into obtaining a &ldquo;complete&rdquo; solution of this equation, involving
+n + 1 arbitrary constants. This aspect of the subject, as a problem
+in partial differential equations, has received great attention at the
+hands of mathematicians, but must be passed over here.</p>
+
+<p>There is a similar theory
+<span class="sidenote">Characteristic function.</span>
+for the function</p>
+
+<p class="center">A = 2 <span class="f150">&int;</span> Tdt = S + H&tau;</p>
+<div class="author">(8)</div>
+
+<p class="noind">It follows from (4) that</p>
+
+<p class="center">&delta;A = &tau;&delta;H + p&prime;<span class="su">1</span>&delta;q&prime;<span class="su">1</span> + p&prime;<span class="su">2</span>&delta;q&prime;<span class="su">2</span> + ...
+ &minus; p<span class="su">1</span>&delta;q<span class="su">1</span> &minus; p<span class="su">2</span>&delta;q<span class="su">2</span> &minus; ....</p>
+<div class="author">(9)</div>
+
+<p class="noind">This formula (it may be remarked) contains the principle of &ldquo;least
+<span class="pagenum"><a name="page763" id="page763"></a>763</span>
+action&rdquo; as a particular case. Selecting, as before, any two arbitrary
+configurations, it is in general possible to start the system from one
+of these, with a prescribed value of the total energy H, so that it
+shall pass through the other. Hence, regarding A as a function of
+the initial and final co-ordinates and the energy, we find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p&prime;<span class="su">1</span> =</td> <td>&part;A</td>
+<td rowspan="2">, &emsp; p&prime;<span class="su">2</span> =</td> <td>&part;A</td>
+<td rowspan="2">, ... ,</td></tr>
+<tr><td class="denom">&part;q&prime;<span class="su">1</span></td> <td class="denom">&part;q&prime;<span class="su">2</span></td></tr></table>
+<div class="author">(10)</div>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">p<span class="su">1</span> = &minus;</td> <td>&part;A</td>
+<td rowspan="2">, &emsp; p<span class="su">2</span> = &minus;</td> <td>&part;A</td>
+<td rowspan="2">, ... ,</td></tr>
+<tr><td class="denom">&part;q<span class="su">1</span></td> <td class="denom">&part;q<span class="su">2</span></td></tr></table>
+
+<p class="noind">and</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&tau; =</td> <td>&part;A</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">&part;H</td></tr></table>
+<div class="author">(11)</div>
+
+<p class="noind">A is called by Hamilton the <i>characteristic function</i>; it represents,
+of course, the &ldquo;action&rdquo; of the system in the free motion (with
+prescribed energy) between the two configurations. Like S, it
+satisfies a partial differential equation, obtained by substitution
+from (10) in (7).</p>
+
+<p>The preceding theorems are easily adapted to the case of cyclic
+systems. We have only to write</p>
+
+<p class="center">S = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+  (R &minus; V) dt = <span class="f150">&int;</span><span class="sp1">t&prime;</span><span class="su2">t</span>
+  (T &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; ... &minus; V) dt</p>
+<div class="author">(12)</div>
+
+<p class="noind">in place of (1), and</p>
+
+<p class="center">A = <span class="f150">&int;</span> (2T &minus; &kappa;&chi;&#729; &minus; &kappa;&prime;&chi;&#729;&prime; &minus; ...) dt,</p>
+<div class="author">(13)</div>
+
+<p class="noind">in place of (8); cf. § 7 <i>ad fin</i>. It is understood, of course, that in
+(12) S is regarded as a function of the initial and final values of the
+palpable co-ordinates q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>, and of the time of transit &tau;, the
+cyclic momenta being invariable. Similarly in (13), A is regarded
+as a function of the initial and final values of q<span class="su">1</span>, q<span class="su">2</span>, ... q<span class="su">m</span>, and of the
+total energy H, with the cyclic momenta invariable. It will be
+found that the forms of (4) and (9) will be conserved, provided the
+variations &delta;q<span class="su">1</span>, &delta;q<span class="su">2</span>, ... be understood to refer to the palpable co-ordinates
+alone. It follows that the equations (5), (6) and (10),
+(11) will still hold under the new meanings of the symbols.</p>
+
+<p class="pt2 center">9. <i>Reciprocal Properties of Direct and Reversed Motions.</i></p>
+
+<p>We may employ Hamilton&rsquo;s principal function to prove a very
+remarkable formula connecting any <i>two</i> slightly disturbed
+<span class="sidenote">Lagrange&rsquo;s formula.</span>
+natural motions of the system. If we use the symbols
+&delta; and &Delta; to denote the corresponding variations, the
+theorem is</p>
+
+<table class="math0" summary="math">
+<tr><td>d</td> <td rowspan="2">&Sigma; (&delta;p<span class="su">r</span>·&Delta;q<span class="su">r</span> &minus; &Delta;p<span class="su">r</span>·&delta;q<span class="su">r</span>) = 0;</td></tr>
+<tr><td class="denom">dt</td></tr></table>
+<div class="author">(1)</div>
+
+<p class="noind">or integrating from t to t&prime;,</p>
+
+<p class="center">&Sigma; (&delta;p&prime;<span class="su">r</span>·&Delta;q&prime;<span class="su">r</span> &minus; &Delta;q&prime;<span class="su">r</span>·&delta;q&prime;<span class="su">r</span>) = &Sigma; (&delta;p<span class="su">r</span>·&Delta;q<span class="su">r</span> &minus; &Delta;p<span class="su">r</span>·&delta;q<span class="su">r</span>).</p>
+<div class="author">(2)</div>
+
+<p class="noind">If for shortness we write</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">(r, s) =</td> <td>&part;²S</td>
+<td rowspan="2">, &emsp; (r, s&prime;) =</td> <td>&part;²S</td>
+<td rowspan="2">,</td></tr>
+<tr><td class="denom">&part;q<span class="su">r</span>&part;q<span class="su">s</span></td> <td class="denom">&part;q<span class="su">r</span>&part;q&prime;<span class="su">s</span></td></tr></table>
+<div class="author">(3)</div>
+
+<p class="noind">we have</p>
+
+<p class="center">&part;p<span class="su">r</span> = &minus;&Sigma;<span class="su">s</span> (r, s) &delta;q<span class="su">s</span> &minus; &Sigma;<span class="su">s</span> (r, s&prime;) &delta;q&prime;<span class="su">s</span></p>
+<div class="author">(4)</div>
+
+<p class="noind">with a similar expression for &Delta;p<span class="su">r</span>. Hence the right-hand side of
+(2) becomes</p>
+
+<p class="center">&minus; &Sigma;<span class="su">r</span> {&Sigma;<span class="su">s</span>(r, s) &delta;q<span class="su">s</span> + &Sigma;<span class="su">s</span>(r, s&prime;) &delta;q&prime;<span class="su">s</span>} &Delta;q<span class="su">r</span> + &Sigma;<span class="su">r</span> {&Sigma;<span class="su">s</span>(r, s)&Delta;q<span class="su">s</span> + &Sigma;<span class="su">s</span>(r, s&prime;) &Delta;q&prime;<span class="su">s</span>} &delta;q<span class="su">r</span></p>
+
+<p class="center">= &Sigma;<span class="su">r</span>&Sigma;<span class="su">s</span>(r, s&prime;) {&delta;q<span class="su">r</span>·&Delta;q&prime;<span class="su">s</span> &minus; &Delta;q<span class="su">r</span>·&delta;q&prime;<span class="su">s</span>}.</p>
+<div class="author">(5)</div>
+
+<p class="noind">The same value is obtained in like manner for the expression on
+the left hand of (2); hence the theorem, which, in the form (1),
+is due to Lagrange, and was employed by him as the basis of his
+method of treating the dynamical theory of <i>Variation of Arbitrary
+Constants</i>.</p>
+
+<p>The formula (2) leads at once to some remarkable reciprocal relations
+which were first expressed, in their complete form, by
+Helmholtz. Consider any natural motion of a conservative
+system between two configurations O and O&prime;
+<span class="sidenote">Helmholtz&rsquo;s reciprocal theorems.</span>
+through which it passes at times t and t&prime; respectively,
+and let t&prime; &minus; t = &tau;. As the system is passing through O
+let a small impulse &delta;p<span class="su">r</span> be given to it, and let the consequent
+alteration in the co-ordinate q<span class="su">s</span> after the time &tau; be &delta;q&prime;<span class="su">s</span>. Next
+consider the <i>reversed</i> motion of the system, in which it would, if
+undisturbed, pass from O&prime; to O in the same time &tau;. Let a small
+impulse &delta;p&prime;<span class="su">s</span> be applied as the system is passing through O&prime;, and
+let the consequent change in the co-ordinate q<span class="su">r</span> after a time &tau; be &delta;q<span class="su">r</span>.
+Helmholtz&rsquo;s first theorem is to the effect that</p>
+
+<p class="center">&delta;q<span class="su">r</span> : &delta;p&prime;<span class="su">s</span> = &delta;q&prime;<span class="su">s</span> : &delta;p<span class="su">r</span>.</p>
+<div class="author">(6)</div>
+
+<p class="noind">To prove this, suppose, in (2), that all the &delta;q vanish, and likewise
+all the &delta;p with the exception of &delta;p<span class="su">r</span>. Further, suppose all the &Delta;q&prime;
+to vanish, and likewise all the &Delta;p&prime; except &Delta;p&prime;<span class="su">s</span>, the formula then
+gives</p>
+
+<p class="center">&delta;p<span class="su">r</span>·&Delta;q<span class="su">r</span> = &minus;&Delta;p&prime;<span class="su">s</span>·&delta;q&prime;<span class="su">s</span>,</p>
+<div class="author">(7)</div>
+
+<p class="noind">which is equivalent to Helmholtz&rsquo;s result, since we may suppose
+the symbol &Delta; to refer to the reversed motion, provided we
+change the signs of the &Delta;p. In the most general motion of a top
+(<span class="sc"><a href="#artlinks">Mechanics</a></span>, § 22), suppose that a small impulsive couple about the
+vertical produces after a time &tau; a change &delta;&theta; in the inclination of the
+axis, the theorem asserts that in the reversed motion an equal impulsive
+couple in the plane of &theta; will produce after a time &tau; a change
+&delta;&psi;, in the azimuth of the axis, which is equal to &delta;&theta;. It is understood,
+of course, that the couples have no components (in the
+generalized sense) except of the types indicated; for instance, they
+may consist in each case of a force applied to the top at a point of
+the axis, and of the accompanying reaction at the pivot. Again, in
+the corpuscular theory of light let O, O&prime; be any two points on the axis
+of a symmetrical optical combination, and let V, V&prime; be the corresponding
+velocities of light. At O let a small impulse be applied perpendicular
+to the axis so as to produce an angular deflection &delta;&theta;, and
+let &beta;&prime; be the corresponding lateral deviation at O&prime;. In like manner
+in the reversed motion, let a small deflection &delta;&theta;&prime; at O&prime; produce a
+lateral deviation &beta; at O. The theorem (6) asserts that</p>
+
+<table class="math0" summary="math">
+<tr><td>&beta;</td> <td rowspan="2">=</td>
+<td>&beta;&prime;&beta;&prime;</td> <td rowspan="2">,</td></tr>
+<tr><td class="denom">V&prime;&delta;&theta;&prime;</td> <td class="denom">V&delta;&theta;</td></tr></table>
+<div class="author">(8)</div>
+
+<p class="noind">or, in optical language, the &ldquo;apparent distance&rdquo; of O from O&prime; is to
+that of O&prime; from O in the ratio of the refractive indices at O&prime; and O
+respectively.</p>
+
+<p>In the second reciprocal theorem of Helmholtz the configuration
+O is slightly varied by a change &delta;q<span class="su">r</span> in one of the co-ordinates,
+the momenta being all unaltered, and &delta;q&prime;<span class="su">s</span> is
+<span class="sidenote">Helmholtz&rsquo;s second reciprocal theorem.</span>
+the consequent variation in one of the momenta after
+time &tau;. Similarly in the reversed motion a change &delta;p&prime;<span class="su">s</span>
+produces after time &tau; a change of momentum &delta;p<span class="su">r</span>. The
+theorem asserts that</p>
+
+<p class="center">&delta;p&prime;<span class="su">s</span> : &delta;q<span class="su">r</span> = &delta;p<span class="su">r</span> : &delta;q&prime;<span class="su">s</span></p>
+<div class="author">(9)</div>
+
+<p class="noind">This follows at once from (2) if we imagine all the &delta;p to vanish, and
+likewise all the &delta;q save &delta;q<span class="su">r</span>, and if (further) we imagine all the &Delta;p&prime;
+to vanish, and all the &Delta;q&prime; save &Delta;q&prime;<span class="su">s</span>. Reverting to the optical
+illustration, if F, F&prime;, be principal foci, we can infer that the convergence
+at F&prime; of a parallel beam from F is to the convergence at F of
+a parallel beam from F&prime; in the inverse ratio of the refractive indices
+at F&prime; and F. This is equivalent to Gauss&rsquo;s relation between the
+two principal focal lengths of an optical instrument. It may be
+obtained otherwise as a particular case of (8).</p>
+
+<p>We have by no means exhausted the inferences to be drawn from
+Lagrange&rsquo;s formula. It may be noted that (6) includes as particular
+cases various important reciprocal relations in optics and acoustics
+formulated by R.J.E. Clausius, Helmholtz, Thomson (Lord Kelvin)
+and Tait, and Lord Rayleigh. In applying the theorem care must
+be taken that in the reversed motion the reversal is complete, and
+extends to every velocity in the system; in particular, in a cyclic
+system the cyclic motions must be imagined to be reversed with
+the rest. Conspicuous instances of the failure of the theorem
+through incomplete reversal are afforded by the propagation of
+sound in a wind and the propagation of light in a magnetic
+medium.</p>
+
+<p>It may be worth while to point out, however, that there is no
+such limitation to the use of Lagrange&rsquo;s formula (1). In applying
+it to cyclic systems, it is convenient to introduce conditions already
+laid down, viz. that the co-ordinates q<span class="su">r</span> are the palpable co-ordinates
+and that the cyclic momenta are invariable. Special inference can
+then be drawn as before, but the interpretation cannot be expressed
+so neatly owing to the non-reversibility of the motion.</p>
+
+<p><span class="sc">Authorities.</span>&mdash;The most important and most accessible early
+authorities are J.L. Lagrange, <i>Mécanique analytique</i> (1st ed. Paris,
+1788, 2nd ed. Paris, 1811; reprinted in <i>&OElig;uvres</i>, vols. xi., xii., Paris,
+1888-89); Hamilton, &ldquo;On a General Method in Dynamics,&rdquo; <i>Phil. Trans.</i>
+1834 and 1835; C.G.J. Jacobi, <i>Vorlesungen über Dynamik</i> (Berlin,
+1866, reprinted in <i>Werke</i>, Supp.-Bd., Berlin, 1884). An account of
+the extensive literature on the differential equations of dynamics and
+on the theory of variation of parameters is given by A. Cayley,
+&ldquo;Report on Theoretical Dynamics,&rdquo; <i>Brit. Assn. Rep.</i> (1857), <i>Mathematical
+Papers</i>, vol. iii. (Cambridge, 1890). For the modern developments
+reference may be made to Thomson and Tait, <i>Natural Philosophy</i>
+(1st ed. Oxford, 1867, 2nd ed. Cambridge, 1879); Lord
+Rayleigh, <i>Theory of Sound</i>, vol. i. (1st ed. London, 1877; 2nd ed.
+London, 1894); E.J. Routh, <i>Stability of Motion</i> (London, 1877),
+and <i>Rigid Dynamics</i> (4th ed. London, 1884); H. Helmholtz,
+&ldquo;Über die physikalische Bedeutung des Prinzips der kleinsten
+Action,&rdquo; <i>Crelle</i>, vol. c., 1886, reprinted (with other cognate papers)
+in <i>Wiss. Abh.</i> vol. iii. (Leipzig, 1895); J. Larmor, &ldquo;On Least
+Action,&rdquo; <i>Proc. Lond. Math. Soc.</i> vol. xv. (1884); E.T. Whittaker,
+<i>Analytical Dynamics</i> (Cambridge, 1904). As to the question of
+stability, reference may be made to H. Poincaré, &ldquo;Sur l&rsquo;équilibre
+d&rsquo;une masse fluide animée d&rsquo;un mouvement de rotation&rdquo; <i>Acta math.</i>
+vol. vii. (1885); F. Klein and A. Sommerfeld, <i>Theorie des Kreisels</i>,
+pts. 1, 2 (Leipzig, 1897-1898); A. Lioupanoff and J. Hadamard,
+<i>Liouville</i>, 5me série, vol. iii. (1897); T.J.I. Bromwich, Proc. Lond.
+Math. Soc. vol. xxxiii. (1901). A remarkable interpretation of
+various dynamical principles is given by H. Hertz in his posthumous
+work <i>Die Prinzipien der Mechanik</i> (Leipzig, 1894), of which an
+English translation appeared in 1900.</p>
+</div>
+<div class="author">(H. Lb.)</div>
+
+<p><span class="pagenum"><a name="page764" id="page764"></a>764</span></p>
+
+
+<hr class="art" />
+<p><span class="bold">DYNAMITE<a name="ar6" id="ar6"></a></span> (Gr. <span class="grk" title="dynamis">&#948;&#973;&#957;&#945;&#956;&#953;&#962;</span>, power), the name given to several
+explosive preparations containing nitroglycerin (<i>q.v.</i>) which are
+almost exclusively used for blasting purposes. The first practical
+application of nitroglycerin in this way was made by A. Nobel in
+1863. He soaked gunpowder with the liquid and fired the gunpowder
+by an ordinary fuse. Later he found that nitroglycerin
+could be detonated by the explosion of several materials such as
+fulminate of mercury, the use of which as a detonator he patented
+in 1867. In 1866-1867 he experimented with charcoal and other
+substances, and found the infusorial earth known as kieselguhr,
+which consists mainly of silica (nearly 95%), eminently adapted
+to the purpose, as it was inert, non-combustible, and after a little
+heating and preparation very porous, retaining a large amount
+of nitroglycerin as water is held in a sponge, without very serious
+exudation on standing. This kieselguhr dynamite is generally
+made by incorporating three parts of nitroglycerin with one part
+of the dry earth, the paste being then formed into cylindrical
+cartridges. This work is done by hand. Generally a small
+percentage of the kieselguhr is replaced by a mixture containing
+sodium and ammonium carbonates, talc and ochre. This product
+is known as dynamite No. 1. Disabilities attaching to kieselguhr
+dynamite are that when placed in water the nitroglycerin is
+liable to be exuded or displaced, also that, like nitroglycerin
+itself, it freezes fairly easily and thawing the frozen cartridges
+is a dangerous operation. Other substances, <i>e.g.</i> kaolin, tripoli,
+magnesia alba (magnesium carbonate), alumina, sugar, charcoal,
+some powdered salts and mixtures of sawdust and salts, have been
+shown to be absorbents more or less adapted to the purpose of
+making a dynamite. Charcoal from cork is said to absorb about
+90% of its weight of nitroglycerin. With the idea of obtaining
+greater safety, mixtures have been made of nitroglycerin with
+wood fibre, charcoal and metallic nitrates. Lithofracteur, for
+instance, consists of 50% nitroglycerin and a mixture of
+prepared sawdust, kieselguhr and barium nitrate. Carbonite
+contains 25% of nitroglycerin, the remainder being
+a mixture of wood-meal and alkali nitrates, with about 1%
+of sulphur. Dualin, atlas dynamite and potentite are other
+modifications.</p>
+
+<p>A convenient form in which nitroglycerin can be made up for
+blasting purposes, especially in wet ground, is the gelatinous
+material obtained by the action of nitroglycerin, either alone
+or with the help of solvents, on low-grade or soluble gun-cottons.
+It is known as blasting gelatin, and was first made by Nobel
+by incorporating 6 or 7% of low nitrated cellulose (collodion
+cotton or soluble gun-cotton) with slightly warmed nitroglycerin.
+The result is a transparent plastic material, of specific gravity
+1.5 to 1.6, which may be kept under water for a long time without
+appreciable change. It is less sensitive to detonation than
+ordinary dynamite, and although its explosion is slightly slower
+it is more powerful than dynamite and much superior to the
+liquid nitroglycerin. Blasting gelatin also freezes and is
+sensitive to percussion in this state. Camphor and other substances
+have been added to blasting gelatin to render it more
+solid and less sensitive. Some modifications of blasting gelatin,
+<i>e.g.</i> gelignite, contain wood-meal and such oxygen-containing
+salts as potassium nitrate. Experience has conclusively shown
+that dynamites are more satisfactory, quicker, and more intense
+in action than liquid nitroglycerin.</p>
+
+<p>To prevent nitroglycerin and some of the forms of dynamite
+from freezing it has been proposed to add to them small quantities
+of either monochlor-dinitroglycerin or of a nitrated poly-glycerin.
+The former is obtained by first acting upon glycerin with hydrogen
+chloride to produce <i>u-</i>chlorhydrin or chlor-propylene glycol,
+C<span class="su">3</span>H<span class="su">7</span>O<span class="su">2</span>Cl, which is then nitrated as in the case of glycerin. The
+latter is obtained by heating glycerin for six or seven hours to
+about 300° C., whereby water is split off in such manner that a
+diglycerin C<span class="su">6</span>H<span class="su">14</span>O<span class="su">5</span>, for the most part, results. This on nitration
+in the usual manner gives a product C<span class="su">6</span>H<span class="su">10</span>N<span class="su">4</span>O<span class="su">13</span>, which burns and
+explodes in a similar manner to ordinary nitroglycerin, but is
+less sensitive and does not so easily freeze. The mono- and
+di-nitrates of glycerin have also been proposed as additions to
+ordinary nitroglycerin (<i>q.v.</i>) for the same purpose.</p>
+<div class="author">(W. R. E. H.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">DYNAMO<a name="ar7" id="ar7"></a></span> (a shortened form of &ldquo;dynamo-electric machine,&rdquo;
+from Gr. <span class="grk" title="dynamis">&#948;&#973;&#957;&#945;&#956;&#953;&#962;</span>, power), a machine for converting mechanical
+into electrical energy.</p>
+
+<table class="flt" style="float: right; width: 230px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:182px; height:121px" src="images/img764.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 1.</span></td></tr></table>
+
+<p>The dynamo ranks with the telegraph and telephone as one
+of the three striking applications of electrical and magnetic
+science to which the material progress that marked the second
+half of the 19th century was in no small measure due. Since
+the discovery of the principle of the dynamo by Faraday in 1831
+the simple model which he first constructed has been gradually
+developed into the machines of 5000 horse-power or more which
+are now built to meet the needs of large cities for electric lighting
+and power, while at the same time the numbers of dynamos
+in use have increased almost beyond estimate. Yet such was the
+insight of Faraday into the fundamental nature of the dynamo that
+the theory of its action which he laid down has remained essentially
+unchanged. His experiments on the current which was set
+up in a coil of wire during its movement across the poles of a
+magnet led naturally to the explanation of induced electromotive
+force as caused by the linking or unlinking of magnetic
+lines of flux with an electric circuit. For the more definite case
+of the dynamo, however, we may, with Faraday, make the
+transition from line-linkage to the equivalent conception of
+&ldquo;line-cutting&rdquo; as the source of E.M.F.&mdash;in other words, to
+the idea of electric conductors &ldquo;cutting&rdquo; or intersecting<a name="fa1p" id="fa1p" href="#ft1p"><span class="sp">1</span></a> the
+lines of flux in virtue of relative motion of the magnetic field
+and electric circuit. On the 28th of October 1831 Faraday
+mounted a copper disk so that it could be rotated edgewise
+between the poles of a permanent horse-shoe magnet. When
+so rotated, it cut the lines of flux which passed transversely
+through its lower half, and by means of two rubbing contacts,
+one on its periphery and the other on its spindle, the circuit
+was closed through a galvanometer, which indicated the passage
+of a continuous current so long as the disk was rotated (fig. 1).
+Thus by the invention of the first
+dynamo Faraday proved his idea that
+the E.M.F. induced through the interaction
+of a magnetic field and an electric
+circuit was due to the passage of a
+portion of the electric circuit <i>across</i> the
+lines of flux, or vice versa, and so could
+be maintained if the cutting of the
+lines were made continuous.<a name="fa2p" id="fa2p" href="#ft2p"><span class="sp">2</span></a> In comparison
+with Faraday&rsquo;s results, the subsequent advance is to be
+regarded as a progressive perfecting of the mechanical and
+electro-magnetic design, partly from the theoretical and partly
+from the practical side, rather than as modifying or adding to
+the idea which was originally present in his mind, and of which
+he already saw the possibilities.</p>
+
+<p>A dynamo, then, is a machine in which, by means of continuous
+relative motion, an electrical conductor or system of conductors
+forming part of a circuit is caused to cut the lines of a magnetic
+field or fields; the cutting of the magnetic flux induces an electromotive
+force in the conductors, and when the circuit is closed
+a current flows, whereby mechanical energy is converted into
+electrical energy.</p>
+
+<div class="condensed">
+<p>Little practical use could be made of electrical energy so long as its
+only known sources were frictional machines and voltaic batteries.
+The cost of the materials for producing electrical currents on a large
+scale by chemical action was prohibitive, while the frictional machine
+only yielded very small currents at extremely high potentials. In
+the dynamo, on the other hand, electrical energy in a convenient form
+could be cheaply and easily obtained by mechanical means, and
+with its invention the application of electricity to a wide range of
+commercial purposes became economically possible. As a converter
+of energy from one form to another it is only surpassed in efficiency
+by another electrical appliance, namely, the transformer (see
+<span class="sc"><a href="#artlinks">Transformers</a></span>). In this there is merely conversion of electrical
+energy at a high potential into electrical energy at a low potential,
+or vice versa, but in the dynamo the mechanical energy which must
+be applied to maintain the relative movement of magnetic field and
+conductor is absorbed, and reappears in an electrical form. A true
+transformation takes place, and the proportion which the rate of
+<span class="pagenum"><a name="page765" id="page765"></a>765</span>
+delivery of electrical energy bears to the power absorbed, or in other
+words the <i>efficiency</i>, is the more remarkable. The useful return or
+&ldquo;output&rdquo; at the terminals of a large machine may amount to as
+much as 95% of the mechanical energy which forms the &ldquo;input.&rdquo;
+Since it needs some prime mover to drive it, the dynamo has not
+made any direct addition to our sources of energy, and does not
+therefore rank with the primary battery or oil-engine, or even the
+steam-engine, all of which draw their energy more immediately from
+nature. Yet by the aid of the dynamo the power to be derived
+from waterfalls can be economically and conveniently converted
+into an electrical form and brought to the neighbouring factory or
+distant town, to be there reconverted by motors into mechanical
+power. Over any but very short distances energy is most easily
+transmitted when it is in an electrical form, and turbine-driven
+dynamos are very largely and successfully employed for such
+transmission. Thus by conducing to the utilization of water-power
+which may previously have had but little value owing to its disadvantageous
+situation, the dynamo may almost be said to have
+added another to our available natural resources.</p>
+</div>
+
+<p>The two essential parts of the dynamo, as required by its
+definition, may be illustrated by the original disk machine of
+Faraday. They are (1) the <i>iron magnet</i>, between the poles of
+which a magnetic field exists, and (2) the <i>electrical conductors</i>,
+represented by the rotating copper disk. The sector of the disk
+cutting the lines of the field forms part of a closed electric circuit,
+and has an E.M.F. induced in it, by reason of which it is no longer
+simply a conductor, but has become &ldquo;active.&rdquo; In its more
+highly developed form the simple copper disk is elaborated into
+a system of many active wires or bars which form the &ldquo;winding,&rdquo;
+and which are so interconnected as to add up their several
+E.M.F.&rsquo;s. Since these active wires are usually mounted on an
+iron structure, which may be likened to the keeper or &ldquo;armature&rdquo;
+of a magnet rotating between its poles, the term &ldquo;armature&rdquo;
+has been extended to cover not only the iron core, but also
+the wires on it, and when there is no iron core it is even applied
+to the copper conductors themselves. In the dynamo of Faraday
+the &ldquo;armature&rdquo; was the rotating portion, and such is the case
+with modern continuous-current dynamos; in alternators,
+however, the magnet, or a portion of it, is more commonly rotated
+while the armature is stationary. It is in fact immaterial to the
+action whether the one or the other is moved, or both, so long as
+their relative motion causes the armature conductors to cut the
+magnetic flux. As to the ultimate reason why an E.M.F. should
+be thereby induced, physical science cannot as yet yield any
+surer knowledge than in the days of Faraday.<a name="fa3p" id="fa3p" href="#ft3p"><span class="sp">3</span></a> For the engineer,
+it suffices to know that the E.M.F. of the dynamo is due to the
+cutting of the magnetic flux by the active wires, and, further,
+is proportional to the rate at which the lines are cut.<a name="fa4p" id="fa4p" href="#ft4p"><span class="sp">4</span></a></p>
+
+<table class="flt" style="float: right; width: 310px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:261px; height:156px" src="images/img765.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 2.</span></td></tr></table>
+
+<p>The equation of the <i>electromotive force</i> which is required in
+order to render this statement quantitative must contain three
+factors, namely, the density of the flux in the air-gap through
+which the armature conductors move, the active length of these
+wires, and the speed of their movement. For given values of
+the first and third factors and a single straight wire moved
+parallel to itself through a uniform field, the maximum rate of
+cutting is evidently obtained when the three directions of the lines
+of the conductor&rsquo;s length and
+of the relative motion are respectively
+at right angles to
+each other, as shown by the
+three co-ordinate axes of fig. 2.
+The E.M.F. of the single wire is then</p>
+
+<p class="center">E = B<span class="su">g</span>LV × 10<span class="sp">&minus;8</span> volts</p>
+<div class="author">(1)</div>
+
+<p class="noind">where B<span class="su">g</span> is the density of the
+flux within the air-gap expressed
+in C.G.S. lines per
+square centimetre, L is the active length of the conductor
+within the field in centimetres, and V is the velocity of movement
+in centimetres per second. Further, the direction
+in which the E.M.F. has the above maximum value is along
+the length of the conductor, its &ldquo;sense&rdquo; being determined by
+the direction of the movement<a name="fa5p" id="fa5p" href="#ft5p"><span class="sp">5</span></a> in relation to the direction of the
+field.</p>
+
+<p>The second fundamental equation of the dynamo brings to
+light its mechanical side, and rests on H.C. Oersted&rsquo;s discovery
+of the interaction of a magnetic field and an electric current. If
+a straight electric conductor through which a current is passing
+be so placed in a magnetic field that its length is not parallel
+to the direction of the lines of flux, it is acted on by a force which
+will move it, if free, in a definite direction relatively to the
+magnet; or if the conductor is fixed and the magnet is free, the
+latter will itself move in the opposite direction. Now in the
+dynamo the active wires are placed so that their length is at right
+angles to the field; hence when they are rotated and an electric
+current begins to flow under the E.M.F. which they induce, a
+mutual force at once arises between the copper conductors and
+the magnet, and the direction of this force must by Lenz&rsquo;s law
+be opposed to the direction of the movement. Thus as soon
+as the disk of fig. 1 is rotated and its circuit is closed, it experiences
+a mechanical pull or drag which must be overcome by the
+force applied to turn the disk. While the magnet must be firmly
+held so as to remain stationary, the armature must be of such
+mechanical construction that its wires can be forcibly driven
+through the magnetic field against the mutual pull. This law
+of electrodynamic action may be quantitatively stated in an
+<i>equation of mechanical force</i>, analogous to the equation (I.) of
+electromotive force, which states the law of electromagnetic
+induction. If a conductor of length L cm., carrying a current
+C amperes, is immersed in a field of uniform density B<span class="su">g</span>, and the
+length of the conductor is at right angles to the direction of the
+lines, it is acted on by a force</p>
+
+<p class="center">F = B<span class="su">g</span>LC × 10<span class="sp">&minus;1</span> dynes,</p>
+<div class="author">(2)</div>
+
+<p class="noind">and the direction of this force is at right angles to the conductor
+and to the field. The rate at which electrical energy is developed,
+when this force is overcome by moving the conductor as a
+dynamo through the field, is EC = B<span class="su">g</span>LVC × 10<span class="sp">&minus;8</span> watts, whence
+the equality of the mechanical power absorbed and the electrical
+power developed (as required by the law of the conservation
+of energy) is easily established. The whole of this power is not,
+however, available at the terminals of the machine; if R<span class="su">a</span> be the
+resistance of the armature in ohms, the passage of the current C<span class="su">a</span>
+through the armature conductors causes a drop of pressure of
+C<span class="su">a</span>R<span class="su">a</span> volts, and a corresponding loss of energy in the armature
+at the rate of C<span class="su">a</span>²R<span class="su">a</span> watts. As the resistance of the external
+circuit R<span class="su">e</span> is lowered, the current C = E<span class="su">a</span> / (R<span class="su">e</span> + R<span class="su">a</span>) is increased.
+The increase of the current is, however, accompanied by a progressive
+increase in the loss of energy over the armature, and as
+this is expended in heating the armature conductors, their temperature
+may rise so much as to destroy the insulating materials
+with which they are covered. Hence the temperature which
+the machine may be permitted to attain in its working is of great
+importance in determining its output, the current which forms
+one factor therein being primarily limited by the heating which
+it produces in the armature winding. The lower the resistance
+of the armature, the less the rise of its temperature for a given
+current flowing through it; and the reason for the almost
+universal adoption of copper as the material for the armature
+conductors is now seen to lie in its high conductivity.<a name="fa6p" id="fa6p" href="#ft6p"><span class="sp">6</span></a></p>
+
+<p>Since the voltage of the dynamo is the second factor to which
+its output is proportional, the conditions which render the induced
+E.M.F. a maximum must evidently be reproduced as far
+as possible in practice, if the best use is to be made of a given
+mass of iron and copper. The first problem, therefore, in the
+construction of the dynamo is the disposition of the wires and
+field in such a manner that the three directions of field, length of
+active conductors, and movement are at right angles to one
+another, and so that the relative motion is continuous. Reciprocating
+motion, such as would be obtained by direct attachment
+of the conductors to the piston of a steam-engine, has
+<span class="pagenum"><a name="page766" id="page766"></a>766</span>
+been successfully employed only in the special case of an
+&ldquo;oscillator,&rdquo;<a name="fa7p" id="fa7p" href="#ft7p"><span class="sp">7</span></a> producing a small current very rapidly changing
+in direction. Rotary motion is therefore universally adopted,
+and with this two distinct cases arise. Either (A) the active
+length of the wire is parallel to the axis of rotation, or (B) it is at
+right angles to it.</p>
+
+<table class="flt" style="float: right; width: 320px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:178px; height:272px" src="images/img766a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 3.</span></td></tr>
+<tr><td class="figright1"><img style="width:192px; height:201px" src="images/img766b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 4.</span></td></tr></table>
+
+<p>(A) If a conductor is rotated in the gap between the poles of
+a horse-shoe magnet, and these poles have plane parallel faces
+opposing one another as in fig. 3, not only is the density of the
+flux in the interpolar gap small, but the direction of movement
+is not always at right angles to the
+direction of the lines, which for the
+most part pass straight across from one
+opposing face to the other. When the
+conductor is midway between the poles
+(<i>i.e.</i> either at its highest or lowest point),
+it is at this instant sliding along the lines
+and does not cut them, so that its
+E.M.F. is zero. Taking this position as
+the starting-point, as the conductor
+moves round, its rate of line-cutting
+increases to a maximum when it has
+moved through a right angle and is opposite
+to the centre of a pole-face (as in
+fig. 3), from which point onward the
+rate decreases to zero when it has moved
+through 180°. Each time the conductor crosses a line drawn symmetrically
+through the gap between the poles and at right angles
+to the axis of rotation, the E.M.F. along its length is reversed in
+direction, since the motion relatively to the direction of the field
+is reversed. If the ends of the active conductor are electrically
+connected to two collecting rings fixed upon, but insulated from,
+the shaft, two stationary brushes <i>bb</i> can be pressed on the rings
+so as to make a sliding contact. An external circuit can then
+be connected to the brushes, which will form the &ldquo;terminals&rdquo;
+of the machine, the periodically reversed or alternating E.M.F.
+induced in the active conductor will cause an alternating current
+to flow through conductor and external circuit, and the simplest
+form of &ldquo;alternator&rdquo; is obtained. If the field cut by the
+straight conductor is of uniform density, and all the lines pass
+straight across from one pole-face to the other (both of which
+assumptions are approximately correct), a curve connecting the
+instantaneous values of the E.M.F. as ordinates with time
+or degrees of angular movement as abscissae (as shown at the
+foot of fig. 3), will, if the speed of rotation be uniform, be a sine
+curve. If, however, the conductor is mounted on an iron
+cylinder (fig. 4),<a name="fa8p" id="fa8p" href="#ft8p"><span class="sp">8</span></a> a sufficient margin
+being allowed for mechanical clearance
+between it and the poles, not only will
+the reluctance of the magnetic circuit
+be reduced and the total flux and its
+density in the air-gap B<span class="su">g</span> be thereby
+increased, but the path of the lines
+will become nearly radial, except at
+the &ldquo;fringe&rdquo; near the edges of the
+pole-tips; hence the relative directions
+of the movement and of the lines will
+be continuously at right angles. The
+shape of the E.M.F. curve will then be
+as shown in fig. 4&mdash;flat-topped, with rounded corners rapidly
+sloping down to the zero line.</p>
+
+<table class="flt" style="float: right; width: 230px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:182px; height:124px" src="images/img766c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 5.</span></td></tr></table>
+
+<p>But a single wire cannot thus be made to give more than a few
+volts, and while dynamos for voltages from 5 to 10 are required
+for certain purposes, the voltages in common use range from
+100 to 10,000. It is therefore necessary to connect a number
+of such wires in series, so as to form an &ldquo;armature winding.&rdquo;
+If several similar conductors are arranged along the length of
+the iron core parallel to the first (fig. 5), the E.M.F.&rsquo;s generated
+in the conductors which at any
+moment are under the same pole are
+similarly directed, and are opposite to
+the directions of the E.M.F.&rsquo;s in the
+conductors under the other pole (cf
+fig. 5 where the dotted and crossed
+ends of the wires indicate E.M.F.&rsquo;s
+directed respectively towards and away
+from the observer). Two distinct
+methods of winding thence arise, the similarity of the E.M.F.&rsquo;s
+under the same pole being taken advantage of in the first, and
+the opposite E.M.F.&rsquo;s under N and S poles in the second.</p>
+
+<table class="flt" style="float: left; width: 240px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:190px; height:243px" src="images/img766d.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 6.</span></td></tr></table>
+
+<p>1. The first, or <i>ring</i>-winding, was invented by Dr Antonio
+Pacinotti of Florence<a name="fa9p" id="fa9p" href="#ft9p"><span class="sp">9</span></a> in 1860, and was subsequently and independently
+reintroduced in 1870<a name="fa10p" id="fa10p" href="#ft10p"><span class="sp">10</span></a> by the Belgian electrician,
+Zénobe Théophile Gramme, whence it is also frequently called
+the &ldquo;Gramme&rdquo; winding. By this method the farther end of
+conductor 1 (fig. 5) is joined in series to the near end of conductor
+2; this latter lies next to it on the surface of the core or
+immediately above it, so that both are simultaneously under
+the same pole-piece. For this series connexion to be possible, the
+armature core must be a hollow cylinder,
+supported from the shaft on an
+open non-magnetic spider or hub, between
+the arms of which there is room
+for the internal wire completing the
+loop (fig. 6). The end of one complete
+loop or turn embracing one side of the
+armature core thus forms the starting-point
+for another loop, and the process
+can be continued if required to form
+a coil of two or more turns. In the
+ring armature the iron core serves
+the double purpose of conducting the
+lines across from one pole to the
+other, and also of shielding from the magnetic flux the
+hollow interior through which the connecting wires pass. Any
+lines which leak across the central space are cut by the internal
+wires, and the direction of cutting is such that the E.M.F.
+caused thereby opposes the E.M.F. due to the active conductors
+proper on the external surface. If, however, the section of iron
+in the core be correctly proportioned, the number of lines which
+cross the interior will bear but a small ratio to those which pass
+entirely through the iron, and the counter E.M.F. of the internal
+wires will become very small; they may then be regarded simply
+as connectors for joining the external active wires in series.</p>
+
+<table class="flt" style="float: right; width: 220px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:168px; height:213px" src="images/img766e.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 7.</span></td></tr></table>
+
+<p>2. The second or <i>drum</i> method was used in the original
+&ldquo;shuttle-wound&rdquo; armatures invented
+by Dr Werner von Siemens in 1856, and
+is sometimes called the &ldquo;Siemens&rdquo;
+winding. The farther end of conductor 1
+(fig. 5) is joined by a connecting wire to
+the farther end of another conductor
+2&rsquo; situated nearly diametrically opposite
+on the other side of the core and under
+the opposite pole-piece. The near end of
+the complete loop or turn is then brought
+across the end of the core, and can be
+used as the starting-point for another
+loop beginning with conductor 2, which
+is situated by the side of the first conductor. The iron
+core may now be solid from the surface to the shaft, since
+no connecting wires are brought through the centre, and
+each loop embraces the entire armature core (fig. 7). By the
+formation of two loops in the ring armature and of the single loop
+in the drum armature, two active wires are placed in series;
+<span class="pagenum"><a name="page767" id="page767"></a>767</span>
+the curves of instantaneous E.M.F. are therefore similar in shape
+to that of the single wire (fig. 4), but with their ordinates raised
+throughout to double their former height, as shown at the foot
+of fig. 6.</p>
+
+<p>Next, if the free ends of either the ring or drum loops, instead
+of being connected to two collecting rings, are attached to the
+two halves of a split-ring insulated from the shaft (as shown in
+fig. 7 in connexion with a drum armature), and the stationary
+brushes are so set relatively to the loops that they pass over from
+the one half of the split-ring to the other half at the moment
+when the loops are passing the centre of the interpolar gap, and
+so are giving little or no E.M.F., each brush will always remain
+either positive or negative. The current in the external circuit
+attached to the brushes will then have a constant direction,
+although the E.M.F. in the active wires still remains alternating;
+the curve of E.M.F. obtained at the brushes is thus (as in fig. 7)
+entirely above the zero line. The first dynamo of H. Pixii,<a name="fa11p" id="fa11p" href="#ft11p"><span class="sp">11</span></a>
+which immediately followed Faraday&rsquo;s discovery, gave an
+alternating current, but in 1832<a name="fa12p" id="fa12p" href="#ft12p"><span class="sp">12</span></a> the alternator was converted
+into a machine giving a <i>unidirected current</i> by the substitution
+of a rudimentary &ldquo;commutator&rdquo; in place of mercury collecting
+cups.</p>
+
+<p>(B) So far the length of the active wires has been parallel to the
+axis of rotation, but they may equally well be arranged perpendicularly
+thereto. The poles will then have plane faces and the
+active wires will be disposed with their length approximately
+radial to the axis of the shaft. In order to add their E.M.F.&rsquo;s in
+series, two types of winding may be employed, which are precisely
+analogous in principle to the ring and drum windings under
+arrangement (A).</p>
+
+<p>3. The <i>discoidal</i> or flat-ring armature is equivalent to a ring
+of which the radial depth greatly exceeds the length, with the
+poles presented to one side of the ring instead of embracing its
+cylindrical surface. A similar set of poles is also presented to
+the opposite side of the ring, like poles being opposite to one
+another, so that in effect each polar surface is divided into two
+halves, and the groups of lines from each side bifurcate and pass
+circumferentially through the armature core to issue into the
+adjacent poles of opposite sign.</p>
+
+<p>4. In the <i>disk</i> machine, no iron core is necessary for the armature,
+the two opposite poles of unlike sign being brought close
+together, leaving but a short path for the lines in the air-gap
+through which the active wires are rotated.</p>
+
+<table class="flt" style="float: right; width: 360px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:313px; height:167px" src="images/img767.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 8.</span></td></tr></table>
+
+<p>If the above elementary dynamos are compared with fig. 1,
+it will be found that they all possess a distinctive feature which
+is not present in the original disk machine of Faraday. In the
+four types of machine above described each active wire in each
+revolution first cuts the group of lines forming a field in one
+direction, and then cuts the same lines again in the opposite
+direction relatively to the sense of the lines, so that along the
+length of the wire the E.M.F. alternates in direction. But in
+the dynamo of fig. 1 the sector of the copper disk which is at any
+moment moving through the magnetic field and which forms
+the single active element is always cutting the lines in the same
+manner, so that the E.M.F. generated along its radial length is
+continuous and unchanged in direction. This radical distinction
+differentiates the two classes of <i>heteropolar</i> and <i>homopolar</i>
+dynamos, Faraday&rsquo;s disk machine of fig. 1 being the type of the
+latter class. In it the active element may be arranged either
+parallel or at right angles to the axis of rotation; but in both
+cases, in order to increase the E.M.F. by placing two or more
+elements in series, it becomes necessary either (1) to employ
+some form of sliding contact by which the current may be
+collected from the end of one active element and passed round
+a connecting wire into the next element without again cutting
+the field in the reverse direction, or (2) to form on the armature
+a loop of which each side is alternately active and inactive. The
+first method limits the possibilities of the homopolar machine
+so greatly when large currents and high voltages are required
+that it is now only used in rare instances, as <i>e.g.</i> occasionally in
+dynamos driven by steam-turbines which have a very high
+speed of rotation. The second alternative may be carried into
+effect with any of the four methods of armature winding, but
+is practically confined to the drum and disk types. In its drum
+form the field is divided into two or more projecting poles, all
+of the same sign, with intervening neutral spaces of equal width,
+and the span of the loop in the direction of rotation is at least
+equal to the width of a polar projection, as in fig. 8, where two
+polar projections are shown. Each side of the loop then plays
+a dual part; it first cuts the lines of one polar projection and
+generates an E.M.F., and next becomes an inactive connecting
+wire, while the action is taken up by the opposite side of the
+loop which has previously served as a connector but now cuts
+the lines of the next polar projection. The E.M.F. is thus always
+in the same direction along the side which is at any moment
+active, but alternates round the loop as a whole, and the distinctive
+peculiarity of the homopolar machine, so soon as
+any form of &ldquo;winding&rdquo;
+is introduced into its
+armature, is lost. It
+results that the homopolar
+principle, which
+would prima facie appear
+specially suitable for the
+generation of a unidirectional
+E.M.F. and
+continuous current, can
+seldom be used for this
+purpose and is practically confined to alternators. It may
+therefore be said that in almost all dynamos, whether they
+supply an alternating or a continuous current in the external
+circuit, the E.M.F. and current in the armature are alternating.</p>
+
+<p>Ring winding was largely employed in early continuous-current
+dynamos and also in the alternators of Gramme and
+H. Wilde, and later of Auguste de Méritens. Disk winding was
+also successfully introduced for alternators, as in the magneto-machines
+of Nollet (1849) and the alternators of Wilde (1866)
+and Siemens (1878), and its use was continued in the machines
+of W.M. Mordey and S.Z. Ferranti. But although the ring,
+discoidal-ring and disk methods of winding deserve mention
+from their historical importance, experience has shown that
+drum winding possesses a marked superiority for both electrical
+and manufacturing reasons; the three former methods have
+in fact been practically discarded in its favour, so that the drum
+method will hereafter alone be considered.</p>
+
+<p>The drum coil, composed of several loops wound side by side,
+may therefore be regarded as the constituent active element out
+of which the armature winding of the modern dynamo is developed.
+Its application to the multipolar machine is easily
+followed from fig. 9, which illustrates the heteropolar type of
+dynamo. The span of the loops, which is nearly 180° or across
+the diameter of the two-pole machine, is reduced approximately
+to 90° in the four-pole or to 60° in the six-pole machine and so on,
+the curvature of the coil becoming gradually less as the number
+of poles is increased. The passage of a coil through two magnetic
+fields of opposite direction yields a complete wave of E.M.F.,
+such as is shown in fig. 6, and the time in seconds taken to pass
+through such a complete cycle is the &ldquo;period&rdquo; of the alternating
+E.M.F. The number of complete periods through which the
+E.M.F. of the coil passes per second is called the &ldquo;periodicity&rdquo;
+or &ldquo;frequency&rdquo; of the machine. In the bipolar machine this
+<span class="pagenum"><a name="page768" id="page768"></a>768</span>
+is equal to the number of revolutions per second, and in the
+multipolar machine it is equal to the number of pairs of fields
+through which the coil passes in one second; hence in general
+the periodicity is pN / 60, where N = the number of revolutions
+per minute and p = the number of pairs of poles, and this holds
+true of the E.M.F. and current round the coil, even though the
+E.M.F. and current furnished to the external circuit may be
+rendered unidirectional or continuous. The only difference on
+this point is that in the continuous-current machine the poles
+are usually fewer than in the alternator, and the periodicity is
+correspondingly lower. Thus in the former case the number
+of poles ranges from 2 to 12 and the usual frequencies from 5 to
+20; but with alternators the frequencies in commercial use
+range from 25 to 120, and in large machines driven by slow-speed
+engines the number of poles may even be as high as 96.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter" colspan="2"><img style="width:752px; height:335px" src="images/img768a.jpg" alt="" /></td></tr>
+<tr><td class="caption">I. Smooth.</td>
+<td class="caption">II. Toothed.</td></tr>
+<tr><td class="caption" colspan="2"><span class="sc">Fig. 9.</span></td></tr></table>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:383px; height:220px" src="images/img768b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 10.</span></td></tr></table>
+
+<p>The drum coil may be applied either to the external surface
+of a rotating armature, the field-magnet being external and
+stationary (fig. 9), or to the internal surface of a stationary
+armature (fig. 10), the field-magnet being internal and rotating.
+While the former combination is universally adopted
+in the continuous-current dynamo, the latter is more usual in
+the modern alternator. In either case the iron armature core
+must be &ldquo;laminated&rdquo;; the passage of the lines of the field
+across its surface sets up E.M.F.&rsquo;s which are in opposite directions
+under poles of opposite sign, so that if the core were a
+solid mass a current-sheet would flow along its surface opposite
+to a pole, and complete its circuit by passing through the deeper
+layers of metal or by returning in a sheet under a pole of opposite
+sign. Such &ldquo;eddy-currents&rdquo; can be practically avoided by
+dividing the metal core into laminations at right angles to the
+length of the active wires which are themselves arranged to
+secure the greatest rate of line-cutting and maximum E.M.F.
+The production of the eddy-current E.M.F. is not thereby
+prevented, but the paths of the eddy-currents are so broken up
+that the comparatively high resistance with which they meet
+reduces their amount very greatly. The laminae must be lightly
+insulated from one another, right up to their edges, so that the
+E.M.F.&rsquo;s which still act across their thickness will not be added
+up along the length of the core, but will only produce extremely
+small currents circulating through the interior of the separate
+laminations. Each thin iron plate is either coated with an
+insulating varnish or has one of its sides covered with a sheet of
+very thin paper; the thickness of the laminae is usually about
+one-fortieth of an inch, and if this is not exceeded the rate at
+which energy is dissipated by eddy-currents in the core is
+so far reduced that it does not
+seriously impair the efficiency of the
+machine.</p>
+
+<p>Lastly, the drum coils may be
+either attached to the surface of a
+smooth armature core (fig. 9, I.), or
+may be wound through holes formed
+close to the periphery of the core,
+or may be embedded in the slots
+between projecting iron teeth (figs.
+9 [II.] and 10). Originally employed
+by Antonio Pacinotti in connexion
+with ring winding, the toothed
+armature was after some considerable
+use largely discarded in favour
+of the smooth core; it has, however,
+been reintroduced with a
+fuller understanding of the special
+precautions necessitated in its design,
+and it is now so commonly used
+that it may be said to have superseded the smooth-surface
+armature.</p>
+
+<div class="condensed">
+<p>Not only does the toothed armature reduce the length of the
+air-gap to the minimum permitted by mechanical and magnetic
+considerations, and furnish better mechanical protection to the
+armature coils, but it also ensures the positive holding of the active
+wires against the mechanical drag which they experience as they
+pass through the magnetic field. Further, the active wires in the
+toothed armature are relieved of a large proportion of this mechanical
+drag, which is transferred to the iron teeth. The lines of the field,
+after passing through the air-gap proper, divide between the teeth
+and the slots in proportion to their relative permeances. Hence
+at any moment the active wires are situated in a weak field, and
+for a given armature current the force on them is only proportional
+to this weak field. This important result is connected with the
+fact that when the armature is giving current the distribution of
+the lines over the face of each tooth is distorted, so that they become
+denser on the &ldquo;trailing&rdquo; side than on the &ldquo;leading&rdquo; side;<a name="fa13p" id="fa13p" href="#ft13p"><span class="sp">13</span></a> the
+effect of the non-uniform distribution acting on all the teeth is to
+produce a magnetic drag on the armature core proportional to the
+current passing through the wires, so that the total resisting force
+remains the same as if the armature had a smooth core. The amount
+by which the stress on the active wires is reduced entirely depends
+upon the degree to which the teeth are saturated, but, since the
+relative permeability of iron even at a flux density of 20,000 lines
+per sq. cm. is to that of air approximately as 33 : 1, the embedded wires
+are very largely relieved of the driving stress. An additional gain
+is that solid bars of much greater width can be used in the toothed
+armature than on a smooth core without appreciable loss from
+eddy-currents within their mass.</p>
+
+<p>A disadvantage of the slotted core is, however, that it usually
+necessitates the lamination of the pole-pieces. If the top of the slot
+is open, and its width of opening is considerably greater than the
+length of the air-gap from the iron of the pole-face to the surface
+of the teeth, the lines become unequally distributed not only at the
+surface of the teeth, but also at the face of the pole-pieces; and
+this massing of the lines into bands causes the density at the pole-face
+to be rhythmically varied as the teeth pass under it. No such
+variation can take place in a solid mass of metal without the production
+of eddy-currents within it; hence if the width of the slot-opening
+is equal to or exceeds twice the length of the single air-gap,
+lamination of the pole-pieces in the same plane as that of the
+armature core becomes advisable.</p>
+
+<p>If the wires are threaded through holes or tunnels pierced close
+to the periphery of the core, the same advantages are gained as
+with open slots, and lamination of the pole-pieces is rendered unnecessary.
+But on the other hand, the process of winding becomes
+laborious and expensive, while the increase in the inductance of
+<span class="pagenum"><a name="page769" id="page769"></a>769</span>
+the coils owing to their being surrounded by a closed iron circuit
+is prejudicial to sparkless commutation in the continuous-current
+dynamo and to the regulation of the voltage of the alternator. A
+compromise is found in the half-closed slot, which is not uncommon
+in alternators, although the open slot is more usual in continuous-current
+dynamos.</p>
+</div>
+
+<table class="flt" style="float: right; width: 370px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:323px; height:323px" src="images/img769a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 11.</span></td></tr></table>
+
+<p>With the addition of more turns to the elementary drum loop
+or of several complete coils, new questions arise, and in connexion
+therewith the two great classes of machines, viz. alternators
+and continuous-current dynamos, which have above been
+treated side by side, diverge considerably, so that they are best
+considered separately. The electromotive-force equation of
+the alternator will be
+first deduced, and subsequently
+that of the
+continuous-current
+machine.</p>
+
+<p>Corresponding to the
+number of pairs of
+poles in the multipolar
+alternator, it is evident
+that there may also be
+an equal number of
+coils as shown diagrammatically
+in fig.
+11. The additional
+coils, being similarly
+situated in respect to
+other pairs of poles,
+will exactly reproduce
+the E.M.F. of the original coil in phase and magnitude, so
+that when they are connected in series the total E.M.F. will
+be proportional to the number of coils in series; or if they
+are connected in parallel, while not adding to the E.M.F., they
+will proportionately increase the current-carrying capacity of
+the combination. But within each coil the addition of more
+loops will not cause an equal increase in the total E.M.F., unless
+the phases of the component E.M.F.&rsquo;s due to the several turns
+are identical, and on this account it becomes necessary to
+consider the effect of the width of the coil-side.</p>
+
+<table class="flt" style="float: left; width: 280px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:234px; height:283px" src="images/img769b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 12.</span></td></tr></table>
+
+<p>If the additional loops are wound within the same slots as the
+original loop, the winding is &ldquo;concentrated,&rdquo; and each turn will
+then add the same E.M.F. But if the coil-side is divided between
+two or more slots, the phase of the E.M.F. yielded by the wires
+in one slot being different from that of the wires in another
+neighbouring slot, the sum of all the E.M.F.&rsquo;s will be less than
+the E.M.F. of one component loop
+multiplied by the number of loops
+or turns in the coil. The percentage
+reduction in the E.M.F.
+will depend upon the number of
+the slots in a coil-side and their
+distance apart, <i>i.e.</i> on the virtual
+width of the coil-side expressed as
+a fraction of the &ldquo;pole-pitch&rdquo; or
+the distance measured along the
+pitch-line from the centre of one
+pole to the centre of a neighbouring
+pole of opposite sign (fig. 12).
+The winding is now to be regarded
+as &ldquo;grouped,&rdquo; since a small
+number of distinct phases corresponding
+to the groups within the two, three or four slots have
+to be compounded together. As the number of slots per coil-side
+is increased, an approach is gradually made to the case
+of &ldquo;uniform distribution,&rdquo; such as would obtain in a smooth-core
+armature in which the turns of the coil are wound closely
+side by side. Thus in the six-turn coil of fig. 12 A, which
+represents the development of a two-pole armature when the
+core is cut down to the shaft and opened out flat, there are
+in effect six phases compounded together, each of which differs
+but little from that of its next neighbour. With numerous
+wires lying still closer together a large number of phases are
+compounded until the distribution becomes practically uniform;
+the decrease in the E.M.F., as compared with that of a single
+turn multiplied by the number in series, is then immediately
+dependent upon the width of the coil-side relatively to the pole-pitch.</p>
+
+<table class="flt" style="float: right; width: 250px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:199px; height:141px" src="images/img769c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 13.</span></td></tr></table>
+
+<p>If the width of the inner loop of fig. 12 A is less than that of
+the pole-face, its two sides will for some portion of each period
+be moving under the same pole, and &ldquo;differential action&rdquo;
+results, the net E.M.F. being only that due to the difference
+between the E.M.F.&rsquo;s of the two sides. The loop of smallest
+width must therefore exceed the width of pole-face, if direct
+differential action is to be avoided. The same consideration also
+determines the width of the outer loop; if this be deducted from
+twice the pole-pitch, the difference should not be less than the
+width of the pole-face, so that, <i>e.g.</i>, in a bipolar machine the outer
+loop may stand to the S. pole exactly
+as the inner loop stands to the N.
+pole (fig. 13). In other words, the
+width of the coil-side must not exceed
+the width of the interpolar gap
+between two fields. Evidently then
+if the ratio of the pole-width to the
+pole-pitch approaches unity, the
+width of the coil-side must be very
+small, and vice versa. A compromise between these conflicting
+considerations is found if the pole is made not much
+more than half the pole-pitch, and the width of the coil-side is
+similarly about half the pole-pitch and therefore equal in width
+to the pole (fig. 13). A single large coil, such as that of fig. 12 A,
+can, however, equally well be divided into two halves by taking
+the end-connexions of one half of the turns round the opposite
+side of the shaft (fig. 12 B), as indeed has already been done
+in fig. 13. Each sheaf or band of active wires corresponding
+to a pole is thereby unaffected, but the advantages are gained
+that the axial length of the end-connexions is halved, and that
+they have less inductance. Thus if in fig. 11 there are four turns
+per coil, fig. 14 is electrically equivalent to it (save that the coils
+are here shown divided into two parallel paths, each carrying
+half the total current). When the large coils are divided as
+above described, it results that there are as many coils as there
+are poles, the outer loop of the small coil having a width equal
+to the pole-pitch, and the inner a width equal to the pole-face.</p>
+
+<table class="flt" style="float: left; width: 380px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:326px; height:324px" src="images/img769d.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 14.</span></td></tr></table>
+
+<p>Such is the form which the &ldquo;single-phase alternator&rdquo; takes,
+but since only one-half of the armature core is now covered
+with winding, an entirely
+distinct but
+similar set of coils
+may be wound to form
+a second armature
+circuit between the
+coils of the first circuit.
+The phase of
+this second circuit will
+differ by 90° or a
+quarter of a period
+from that of the first,
+and it may either be
+used to feed an entirely
+separate external
+circuit possibly at a
+different pressure or, if
+it be composed of the
+same number of turns and therefore gives the same voltage, it may
+be interconnected with the first circuit to form a &ldquo;quarter-phase
+alternator,&rdquo; as will be more fully described later. By an extension
+of the same process, if the width of each side of a coil is
+reduced to one-sixth of the pole-pitch, three armature circuits
+can be wound on the same core, and a &ldquo;three-phase alternator,&rdquo;
+giving waves of E.M.F. differing in phase by 120°, is obtained.</p>
+
+<div class="condensed">
+<p>The fundamental &ldquo;electromotive-force equation&rdquo; of the heteropolar
+alternator can now be given a more definite form. Let Z<span class="su">a</span> be
+the number of C. G. S. lines or the total flux, which issuing from any
+<span class="pagenum"><a name="page770" id="page770"></a>770</span>
+one pole flows through the armature core, to leave it by another pole
+of opposite sign. Since each active wire cuts these lines, first as they
+enter the armature core and then as they emerge from it to enter
+another pole, the total number of lines cut in one revolution by any
+one active wire is 2pZ<span class="su">a</span>. The time in seconds taken by one revolution
+is 60/N. The average E.M.F. induced in each active wire in one
+revolution being proportional to the number of lines cut divided
+by the time taken to cut them is therefore 2Z<span class="su">a</span> (pN / 60) × 10<span class="sp">&minus;8</span> volts.
+The active wires which are in series and form one distinct phase
+may be divided into as many bands as there are poles; let each
+such band contain t active wires, which as before explained may
+either form one side of a single large coil or the adjacent sides of
+two coils when the large coil is divided into two halves. Since the
+wires are joined up into loops, two bands are best considered together,
+which with either arrangement yield in effect a single coil of t turns.
+The average E.M.F.&rsquo;s of all the wires in the two bands when added
+together will therefore be 4Z<span class="su">a</span> (pN / 60)t × 10<span class="sp">&minus;8</span>. But unless each band
+is concentrated within a single slot, there must be some differential
+action as they cross the neutral line between the poles, so that the
+last expression is virtually the <i>gross</i> average E.M.F. of the loops
+on the assumption that the component E.M.F.&rsquo;s always act in agreement
+round the coil and do not at times partially neutralize one
+another. The <i>net</i> average E.M.F. of the coil as a whole, or the
+arithmetical mean of all the instantaneous values of a half-wave
+of the actual E.M.F. curve, is therefore reduced to an extent depending
+upon the amount of differential action and so upon the width
+of the coil-side when this is not concentrated. Let k&prime; = the coefficient
+by which the gross average E.M.F. must be multiplied to
+give the net average E.M.F.; then k&prime; may be called the &ldquo;width-factor,&rdquo;
+and will have some value less than unity when the wires
+of each band are spread over a number of slots. The net average
+E.M.F. of the two bands corresponding to a pair of poles is thus
+e<span class="su">av</span> = 4k&prime;Z<span class="su">a</span> (pN / 60)t × 10<span class="sp">&minus;8</span>.</p>
+
+<p>The shape of the curve of instantaneous E.M.F. of the coil must
+further be taken into account. The &ldquo;effective&rdquo; value of an alternating
+E.M.F. is equal to the square root of the mean square of its
+instantaneous values, since this is the value of the equivalent unidirectional
+and unvarying E.M.F., which when applied to a given
+resistance develops energy at the same rate as the alternating
+E.M.F., when the effect of the latter is averaged over one or any
+whole number of periods. Let k&Prime; = the ratio of the square root of the
+mean square to the average E.M.F. of the coil, <i>i.e.</i> = effective E.M.F. / average E.M.F.
+Since it depends upon the shape of the E.M.F. curve, k&Prime; is also
+known as the &ldquo;form-factor&rdquo;; thus if the length of gap between
+pole-face and armature core and the spacing of the wires were so
+graduated as to give a curve of E.M.F. varying after a sine law,
+the form-factor would have the particular value of &pi;/2 &radic;2 = 1.11,
+and to this condition practical alternators more or less conform.
+The effective E.M.F. of the two bands corresponding to a pair of poles
+is thus e<span class="su">eff</span> = 4k&prime;k&Prime;Z<span class="su">a</span> (pN / 60)t × 10<span class="sp">&minus;8</span>.</p>
+
+<p>In any one phase there are p pairs of bands, and these may be
+divided into q parallel paths, where q is one or any whole number
+of which p is a multiple. The effective E.M.F. of a complete phase
+is therefore pe<span class="su">eff</span>/q. Lastly, if m = the number of phases into which
+the armature winding is divided, and &tau; = the total number of active
+wires on the armature counted all round its periphery, t = &tau; / 2pm,
+and the effective E.M.F. per phase is E<span class="su">a</span> = 2k&prime;k&Prime;Z<span class="su">a</span> (pN&tau; / 60mq) × 10<span class="sp">&minus;8</span>.</p>
+
+<p>The two factors k&prime; and k&Prime; may be united into one coefficient, and
+the equation then takes its final form</p>
+
+<p class="center">E<span class="su">a</span> = 2KZ<span class="su">a</span> (pN&tau; / 60mq) × 10<span class="sp">&minus;8</span> volts</p>
+<div class="author1">(1<i>a</i>)</div>
+
+<p class="noind">In the alternator q is most commonly 1, and there is only one circuit
+per phase; finally the value of K or the product of the width-factor
+and the form-factor usually falls between the limits of 1 and 1.25.</p>
+</div>
+
+<p>We have next to consider the effect of the addition of more
+armature loops in the case of dynamos which give a unidirectional
+E.M.F. in virtue of their split-ring collecting device, <i>i.e.</i> of the
+type shown in fig. 7 with drum armature or its equivalent ring
+form. As before, if the additional loops are wound in continuation
+of the first as one coil connected to a single split-ring, this
+coil must be more or less concentrated into a narrow band;
+since if the width becomes nearly equal to or exceeds the width
+of the interpolar gap, the two edges of the coil-side will just as in
+the alternator act differentially against one another during part
+of each revolution. The drum winding with a single coil thus
+gives an armature of the H- or &ldquo;shuttle&rdquo; form invented by
+Dr Werner von Siemens. Although the E.M.F. of such an
+arrangement may have a much higher maximum value than that
+of the curve of fig. 7 for a single loop, yet it still periodically
+varies during each revolution and so gives a pulsating current,
+which is for most practical uses unsuitable. But such pulsation
+might be largely reduced if, for example, a second coil were
+placed at right angles to the original coil and the two were connected
+in series; the crests of the wave of E.M.F. of the second
+coil will then coincide with the hollows of the first wave, and
+although the maximum of the resultant curve of E.M.F. may
+be no higher its fluctuations will be greatly decreased. A
+spacial displacement of the new coils along the pole-pitch,
+somewhat as in a polyphase machine, thus suggests itself, and
+the process may be carried still further by increasing the number
+of equally spaced coils, provided that they can be connected
+in series and yet can have their connexion with the external
+circuit reversed as they pass the neutral line between the poles.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:467px; height:260px" src="images/img770a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 15.</span></td></tr></table>
+
+<table class="flt" style="float: right; width: 150px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:98px; height:142px" src="images/img770b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 16.</span></td></tr></table>
+
+<p>Given two coils at right angles and with their split-rings
+displaced through a corresponding angle of 90°, they may be
+connected in series by joining one brush to the opposite brush
+of the second coil, the external circuit being applied to the two
+remaining brushes.<a name="fa14p" id="fa14p" href="#ft14p"><span class="sp">14</span></a> The same arrangement may again be repeated
+with another pair of coils in parallel with the first, and
+we thus obtain fig. 15 with four split-rings, their connexions to
+the loops being marked by corresponding numerals; the four
+coils will give the same E.M.F. as the two, but they will be jointly
+capable of carrying twice the current, owing to their division
+into two parallel circuits. Now in place of the four split-rings
+may be employed the greatly simplified four-segment structure
+shown in fig. 16, which serves precisely the same purpose as the
+four split-rings but only requires two instead of eight brushes.
+The effect of joining brush 2 in fig. 15 across to brush 3, brush 4
+to brush 5, 5 to 6, &amp;c., has virtually been to connect the end
+of coil A with the beginning of coil B, and the end of coil B with
+the beginning of coil A&prime;, and so on, until they form a continuous
+closed helix. Each sector of fig. 16 will therefore replace two
+halves of a pair of adjacent split-rings, if the end and beginning
+of a pair of adjacent coils are connected to it in a regular order
+of sequence. The four sectors are insulated from one another
+and from the shaft, and the whole structure is
+known as the &ldquo;commutator,&rdquo;<a name="fa15p" id="fa15p" href="#ft15p"><span class="sp">15</span></a> its function
+being not simply to collect the current but also
+to commute its direction in any coil as it passes
+the interpolar gap. The principle of the &ldquo;closed-coil
+continuous-current armature&rdquo; is thus reached,
+in which there are at least two parallel circuits
+from brush to brush, and from which a practically
+steady current can be obtained. Each coil
+is successively short-circuited, as a brush bridges
+over the insulation between the two sectors which terminate
+it; and the brushes must be so set that the period of
+short-circuit takes place when the coil is generating little
+or no E.M.F., <i>i.e.</i> when it is moving through the zone between
+the pole-tips. The effect of the four coils in reducing the
+percentage fluctuation of the E.M.F. is very marked, as
+shown at the foot of fig. 15 (where the upper curve is the
+resultant obtained by adding together the separate curves
+of coils A and B), and the levelling process may evidently be
+carried still further by the insertion of more coils and more
+corresponding sectors in the commutator, until the whole
+<span class="pagenum"><a name="page771" id="page771"></a>771</span>
+armature is covered with winding. For example, figs. 17 and 18
+show a ring and a drum armature, each with eight coils and
+eight commutator sectors; their resultant curve, on the assumption
+that a single active wire gives the flat-topped curve of fig. 4,
+will be the upper wavy line
+of E.M.F. obtained by adding
+together two of the resultant
+curves of fig. 15, with a relative
+displacement of 45°. The
+amount of fluctuation for a
+given number of commutator
+sectors depends upon the shape
+of the curve of E.M.F. yielded
+by the separate small sections
+of the armature winding; the
+greater the polar arc, the less
+the fluctuation. In practice,
+with a polar arc equal to about
+0.75 of the pitch, any number
+of sectors over 32 per pair of
+poles yields an E.M.F. which
+is sensibly constant throughout
+one or any number of
+revolutions.</p>
+
+<table class="flt" style="float: right; width: 310px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:230px; height:174px" src="images/img771a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 17.</span></td></tr>
+<tr><td class="figright1"><img style="width:260px; height:301px" src="images/img771b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 18.</span></td></tr></table>
+
+<div class="condensed">
+<p>The fundamental electro-motive-force
+equation of the
+continuous-current heteropolar
+machine is easily obtained by
+analogy from that of the alternator.
+The gross average
+E.W.F. from the two sides of
+a drum loop without reference
+to its direction is as before
+4Z<span class="su">a</span> (pN / 60) × 10<span class="sp">&minus;8</span> volts. But for
+two reasons its net average E.M.F.
+may be less; the span of the loop may be less than the pole-pitch,
+so that even when the brushes are so set that the position of short-circuit
+falls on the line where the field changes its direction, the two
+sides of the loop for some little time act against each other; or,
+secondly, even if the span of the loop be equal to the pole-pitch, the
+brushes may be so set that the reversal of the direction of its induced
+E.M.F. does not coincide with reversal of the current by the passage
+of the coil under the brushes. The net average E.M.F. of the loop
+is therefore proportional to the algebraic sum of the lines which it
+cuts in passing from one brush to another, and this is equal to the
+net amount of the flux which is included within the loop when
+situated in the position of short-circuit under a brush. The amount
+of this flux may be expressed as k&prime;Z<span class="su">a</span> where k&prime; is some coefficient,
+less than unity if the span of the coil be less than the pole-pitch, and
+also varying with the position of
+the brushes. The net average
+E.M.F. of the loop is therefore</p>
+
+<p class="center">4k&prime;Z<span class="su">a</span> (pN / 60) × 10<span class="sp">&minus;8</span>.</p>
+
+<p>In practice the number of sections
+of the armature winding is so
+large and their distribution round
+the armature periphery is so
+uniform, that the sum total of
+the instantaneous E.M.F.&rsquo;s of
+the several sections which are in
+series becomes at any moment
+equal to the net average E.M.F.
+of one loop multiplied by the
+number which are in series. If
+the winding is divided into q
+parallel circuits, the number of
+loops in series is &tau;/2q, so that the
+total E.M.F. is E<span class="su">a</span> = 2(k&prime; / q) Z<span class="su">a</span> (pN / 60)&tau; × 10<span class="sp">&minus;8</span> volts. Thus as compared
+with the alternator not only is there no division of the
+winding into separate phases, but the form-factor k&prime; disappears,
+since the effective and average E.M.F.&rsquo;s are the same. Further
+whereas in the alternator q may = 1, in the continuous-current
+closed-coil armature there can never be less than two circuits in
+parallel from brush to brush, and if more, their number must always
+be a multiple of two, so that q can never be less than two and
+must always be an even number. Lastly, the factor k&prime; is usually so
+closely equal to 1, that the simplified equation may in practice be
+adopted, viz.</p>
+
+<p class="center">E<span class="su">a</span> = (2/q) (ZpN / 60) &tau; × 10<span class="sp">&minus;8</span> volts.</p>
+<div class="author1">(1<i>b</i>)</div>
+
+<p>The fundamental equation of the electromotive force of the
+dynamo in its fully developed forms (1 <i>a</i>) (and 1 <i>b</i>) may be compared
+with its previous simple statement (I.). The three variable
+terms still find their equivalents, but are differently expressed, the
+density B<span class="su">g</span> being replaced by the total flux of one field Z<span class="su">a</span>, the length
+L of the single active wire by the total number of such wires &tau;, and
+the velocity of movement V by the number of revolutions per second.
+Even when the speed is fixed, an endless number of changes may
+be rung by altering the relative values of the remaining two factors;
+and in successful practice these may be varied between fairly wide
+limits without detriment to the working or economy of the machine.
+While it may be said that the equation of the E.M.F. was implicitly
+known from Faraday&rsquo;s time onwards, the difficulty under which
+designers laboured in early days was the problem of choosing the
+correct relation of Z<span class="su">a</span> or &tau; for the required output; this, again,
+was due chiefly to the difficulty of predetermining the total flux
+before the machine was constructed. The general error lay in
+employing too weak a field and too many turns on the armature, and
+credit must here be given to the American inventors, E. Weston and
+T.A. Edison, for their early appreciation of the superiority in
+practical working of the drum armature, with comparatively few
+active wires rotating in a strong field.</p>
+</div>
+
+<p><i>Continuous-current Dynamos.</i>&mdash;On passing to the separate
+consideration of alternators and continuous-current dynamos,
+the chief constructive features of the latter will first
+be taken in greater detail. As already stated in the
+<span class="sidenote">The armature core.</span>
+continuous-current dynamo the armature is usually
+the rotating portion, and the necessity of laminating its core
+has been generally described. The thin iron stampings employed
+to build up the core take the form of circular washers or &ldquo;disks,&rdquo;
+which in small machines are strung directly on the shaft; in
+larger multipolar machines, in which the required radial depth
+of iron is small relatively to the diameter, a central cast iron
+hub supports the disks. Since the driving force is transmitted
+through the shaft to the disks, they must in the former case be
+securely fixed by keys sunk into the shaft; when a central hub
+is employed (fig. 19) it is keyed to the shaft, and its projecting
+arms engage in notches stamped on the inner circumference
+of the disks, or the latter have dovetailed projections fitting
+into the arms. The disks are then tightly compressed and
+clamped between stout end-plates so as to form a nearly solid
+iron cylinder of axial length slightly exceeding the corresponding
+dimension of the poles. If the armature is more than 4 ft.
+in diameter, the disks become too large to be conveniently
+handled in one piece, and are therefore made in segments, which
+are built up so as to break joint alternately. Prior to assemblage,
+the external circumference of each disk is notched in a
+stamping machine with the required number of slots to receive
+the armature coils, and the longitudinal grooves thereby formed
+in the finished core only require to have their sharp edges
+smoothed off so that there may be no risk of injury to the
+insulation of the coils.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:820px; height:260px" src="images/img771c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 19.</span></td></tr></table>
+
+<p>With open slots either the armature coils may be encased
+with wrappings of oiled linen, varnished paper and thin flexible
+micanite sheeting in order to insulate them electrically
+from the iron slots in which they are afterwards embedded;
+<span class="sidenote">Armature winding.</span>
+or the slots may be themselves lined with
+moulded troughs of micanite, &amp;c., for the reception of the armature
+coils, the latter method being necessary with half-closed
+slots. According to the nature of the coils armatures may be
+divided into the two classes of coil-wound and bar-wound. In
+the former class, round copper wire, double-cotton covered, is
+<span class="pagenum"><a name="page772" id="page772"></a>772</span>
+employed, and the coils are either wound by hand directly on
+to the armature core, or are shaped on formers prior to being
+inserted in the armature slots. Hand-winding is now only
+employed in very small bipolar machines, the process being
+expensive and accompanied by the disadvantage that if one
+section requires to be repaired, the whole armature usually has
+to be dismantled and re-wound. Former-wound coils are, on
+the other hand, economical in labour, perfectly symmetrical
+and interchangeable, and can be thoroughly insulated before
+they are placed in the slots. The shapers employed in the forming
+process are very various, but are usually arranged to give
+to the finished coil a lozenge shape, the two straight active
+sides which fit into the straight slots being joined by V-shaped
+ends; at each apex of the coil the wire is given a twist, so that
+the two sides fall into different levels, an upper and a lower,
+corresponding to the two layers which the coil-sides form on the
+finished armature. Rectangular wire of comparatively small
+section may be similarly treated, and if only one loop is required
+per section, wide and thin strip can be bent into a complete
+loop, so that the only soldered joints are those at the commutator
+end where the loops are interconnected. But finally with
+massive rectangular conductors, the transition must be made to
+bar-winding, in which each bar is a half-loop, insulated by being
+taped after it has been bent to the required shape; the separate
+bars are arranged on the armature in two layers, and their ends
+are soldered together subsequently to form loops. As a general
+rule, whether bars or former-wound coils are employed, the
+armature is barrel-wound, <i>i.e.</i> the end-connexions project outwards
+from the slots with but little change of level, so that they
+form a cylindrical mass supported on projections from the end-plates
+of the core (fig. 19); but, in certain cases, the end-connexions
+are bent downwards at right angles to the shaft, and
+they may then consist of separate strips of copper bent to a
+so-called butterfly or evolute shape.</p>
+
+<p>After the coils or loops have been assembled in the slots on the
+armature core, and the commutator has been fixed in place on
+the shaft, the soldering of the ends of the coils proceeds, by which
+at once the union of the end of one coil with the beginning of the
+next, and also their connexion to the commutator sectors, is
+effected, and in this lies the essential part of armature winding.</p>
+
+<table class="flt" style="float: right; width: 290px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:240px; height:241px" src="images/img772a.jpg" alt="" /></td></tr>
+<tr><td class="caption">Lap-loops<br /><span class="sc">Fig.</span> 20.</td></tr></table>
+
+<div class="condensed">
+<p>The development of the modern drum armature, with its numerous
+coils connected in orderly sequence into a symmetrical winding,
+as contrasted with the earlier Siemens armatures, was
+initiated by F. von Hefner Alteneck (1871), and the laws
+governing the interconnexion of the coils have now been
+elaborated into a definite system of winding formulae. Whatever
+the number of wires or bars in each side of a coil, <i>i.e.</i> whether it
+consist of a single loop or of many turns, the final connexions of its
+free ends are not thereby affected, and it may be mentally replaced
+by a single loop with two active inducing sides. The coil-sides in
+their final position are thus to be
+regarded as separate primary elements,
+even in number, and distributed
+uniformly round the
+armature periphery or divided into
+small, equally spaced groups by
+being located within the slots of a
+toothed armature. Attention must
+then be directed simply to the
+span of the back connexion between
+the elements at the end of the
+armature further from the commutator,
+and to the span of the
+front connexion by which the last
+turn of a coil is finally connected
+to the first turn of the next in
+sequence, precisely as if each coil
+of many turns were reduced to a
+single loop. In order to avoid
+direct differential action, the span of the back connexion which
+fixes the width of the coil must exceed the width of the pole-face,
+and should not be far different from the pole-pitch; it
+is usually a little less than the pole-pitch. Taking any one
+element as No. 1 in fig. 20, where for simplicity a smooth-core
+bipolar armature is shown, the number of winding-spaces, each
+to be occupied by an element, which must be counted off in order
+to find the position of the next element in series, is called the &ldquo;pitch&rdquo;
+of the end-connexion, front or back, as the case may be. Thus the
+back pitch of the winding as marked by the dotted line in fig. 20 is
+7, the second side of the first loop being the element numbered
+1 + 7 = 8. In forming the front end-connexion which completes
+the loop and joins it to the next in succession, two possible cases
+present themselves. By the first, or &ldquo;lap-winding,&rdquo; the front
+end-connexion is brought backwards, and passing on its way to a
+junction with a commutator sector is led to a third element lying
+within the two sides of the first loop, <i>i.e.</i> the second loop starts with
+the element, No. 3, lying next but one to the starting-point of the
+first loop. The winding therefore returns backwards on itself to form
+each front end, but as a whole it works continually forwards round
+the armature, until it finally &ldquo;re-enters,&rdquo; after every element has
+been traversed. The development of the completed winding on a
+flat surface shows that it takes the form of a number of partially
+overlapping loops, whence its name originates. The firm-line
+portion of fig. 21 gives the development of an armature similar to
+that of fig. 18 when cut through at the point marked X and opened
+out; two of the overlapping loops
+are marked thereon in heavy lines.
+The multipolar lap-wound armature
+is obtained by simply repeating the
+bipolar winding p times, as indicated
+by the dotted additions of fig. 21
+which convert it from a two-pole to
+a four-pole machine. The characteristic
+feature of the lap-wound armature
+is that there are as many
+parallel paths from brush to brush,
+and as many points at which the
+current must be collected, as there
+are poles. As the bipolar closed-coil
+continuous-current armature has
+been shown to consist in reality of
+two circuits in parallel, each giving
+the same E.M.F. and carrying half
+the total current, so the multipolar
+lap-wound drum consists of p pairs of parallel paths, each giving
+the same E.M.F. and carrying 1/2p of the total current. Thus in
+equation 1.b we have q = 2p, and the special form which the <i>E.M.F.
+equation of the lap-wound armature</i> takes is E<span class="su">a</span> = Z<span class="su">a</span> (N / 60)&tau; × 10<span class="sp">&minus;8</span>
+volts. All the brushes which are of the same sign must be connected
+together in order to collect the total armature current. The several
+brush-sets of the multipolar lap-wound machine may again be
+reduced to two by &ldquo;cross-connexion&rdquo; of sectors situated 360°/p
+apart, but this is seldom done, since the commutator must then be
+lengthened p times in order to obtain the necessary brush contact-surface
+for the collection of the entire current.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:476px; height:284px" src="images/img772b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 21.</span></td></tr>
+<tr><td class="figcenter"><img style="width:449px; height:229px" src="images/img772d.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 23.</span></td></tr></table>
+
+<table class="flt" style="float: right; width: 290px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:237px; height:245px" src="images/img772c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Wave-loops<br />Fig. 22.</span></td></tr></table>
+
+<p>But for many purposes, especially where the voltage is high and
+the current small, it is advantageous to add together the inductive
+effect of the several poles of the multipolar machine by
+throwing the E.M.F&rsquo;s of half the total number of elements
+<span class="sidenote">Wave-winding.</span>
+into series, the number of parallel circuits being conversely
+again reduced to two. This is effected by the second method of
+winding the closed-coil continuous current drum, which is known
+<span class="pagenum"><a name="page773" id="page773"></a>773</span>
+as &ldquo;wave-winding.&rdquo; The front pitch is now in the same direction
+round the armature as the back pitch (fig. 22), so that the beginning
+of the second loop, <i>i.e.</i> element No. 15, lies outside the first loop.
+After p loops have been formed and as many elements have been
+traversed as there are poles, the distance covered either falls short of
+or exceeds a complete tour of the armature by two winding-spaces,
+or the width of two elements. A second and third tour are then
+made, and so on, until finally the winding again closes upon itself.
+When the completed winding is developed as in fig. 23, it is seen
+to work continuously forwards round the armature in zigzag waves,
+one of which is marked in heavy lines, and the number of complete
+tours is equal to the average of the back and front pitches. Since
+the number of parallel circuits from brush to brush is q = 2, the
+<i>E.M.F. equation of the wave-wound drum</i> is E<span class="su">a</span> = pZ<span class="su">a</span> (N / 60)&tau; × 10<span class="sp">&minus;8</span>
+volts. Only two sets of brushes are necessary, but in order to
+shorten the length of the commutator, other sets may also be added
+at the point of highest and lowest potential up to as many in number
+as there are poles. Thus the advantage of the wave-wound armature
+is that for a given voltage and number of poles the number of active
+wires is only 1/p of that in the lap-wound drum, each being of larger
+cross-section in order to carry p times as much current; hence the
+ratio of the room occupied by the insulation to the copper area is
+less, and the available space is better utilized. A further advantage
+is that the two circuits from brush to brush consist of elements
+influenced by all the poles, so that if for any reason, such as eccentricity
+of the armature within the bore of the pole-pieces, or want of
+uniformity in the magnetic qualities of the poles, the flux of each
+field is not equal to that of every other, the equality of the voltage
+produced by the two halves of the winding is not affected thereby.</p>
+
+<p>In appearance the two classes of armatures, lap and wave, may
+be distinguished in the barrel type of winding by the slope of the
+upper layer of back end-connexions, and that of the front connexions
+at the commutator end being parallel to one another in the latter,
+and oppositely directed in the former.</p>
+</div>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:520px; height:275px" src="images/img773a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 24.</span></td></tr></table>
+
+<p>After completion of the winding, the end-connexions are
+firmly bound down by bands of steel or phosphor bronze binding
+wire, so as to resist the stress of centrifugal force. In the case
+of smooth-surface armatures, such bands are also placed at
+intervals along the length of the armature core, but in toothed
+armatures, although the coils are often in small machines secured
+in the slots by similar bands of a non-magnetic high-resistance
+wire, the use of hard-wood wedges driven into notches at the
+sides of the slots becomes preferable, and in very large machines
+indispensable. The external appearance of a typical armature
+with lap-winding is shown in fig. 24.</p>
+
+<p>A sound mechanical construction of the commutator is of
+vital importance to the good working of the continuous-current
+dynamo. The narrow, wedge-shaped sectors of hard-drawn
+copper, with their insulating strips of thin
+<span class="sidenote">The commutator.</span>
+mica, are built up into a cylinder, tightly clamped
+together, and turned in the lathe; at each end a V-shaped
+groove is turned, and into these are fitted rings of micanite
+of corresponding section (fig. 19); the whole is then slipped
+over a cast iron sleeve, and at either end strong rings are forced
+into the V-shaped grooves under great pressure and fixed by a
+number of closely-pitched tightening bolts. In dynamos driven
+by steam-turbines in which the peripheral speed of the commutator
+is very high, rings of steel are frequently shrunk on the
+surface of the commutator at either end and at its centre. But
+in every case the copper must be entirely insulated from the
+supporting body of metal by the interposition of mica or micanite
+and the prevention of any movement of the sectors under
+frequent and long-continued heating and cooling calls for the
+greatest care in both the design and the manufacture.</p>
+
+<p>On passing to the second fundamental part of the dynamo,
+namely, the field-magnet, its functions may be briefly recalled as
+follows:&mdash;It has to supply the magnetic flux; to provide
+for it an iron path as nearly closed as possible
+<span class="sidenote">Forms of field-magnet.</span>
+upon the armature, save for the air-gaps which must
+exist between the pole-system and the armature core,
+the one stationary and the other rotating; and, lastly, it has
+to give the lines such direction and intensity within the air-gaps
+that they may be cut by the armature wires to the best advantage.
+Roughly corresponding to the three functions above
+summarized are the three portions which are more or less differentiated
+in the complete structure. These are: (1) the magnet
+&ldquo;cores&rdquo; or &ldquo;<i>limbs</i>,&rdquo; carrying the exciting coils whereby the
+inert iron is converted into an electro-magnet; (2) the <i>yoke</i>,
+which joins the limbs together and conducts the flux between
+them; and (3) the <i>pole-pieces</i>, which face the armature and
+transmit the lines from the limbs through the air-gap to the
+armature core, or vice versa.</p>
+
+<table class="flt" style="float: right; width: 190px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:140px; height:165px" src="images/img773b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 25.</span></td></tr></table>
+
+<div class="condensed">
+<p>Of the countless shapes which the field-magnet may take, it
+may be said, without much exaggeration, that almost all have been
+tried; yet those which have proved economical
+and successful, and hence have met with general
+adoption, may be classed under a comparatively
+small number of types. For bipolar
+machines the <i>single horse-shoe</i> (fig. 25), which
+is the lineal successor of the permanent magnet
+employed in the first magneto-electric machines,
+was formerly very largely used. It takes two
+principal forms, according as the pole-pieces and
+armature are above or beneath the magnet
+limbs and yoke. The &ldquo;over-type&rdquo; form is
+best suited to small belt-driven dynamos, while
+the &ldquo;under-type&rdquo; is admirably adapted to be
+directly driven by the steam-engine, the armature
+shaft being immediately coupled to the crank-shaft of the engine.
+In the latter case the magnet must be mounted on non-magnetic
+supports of gun-metal or zinc, so as to hold it at some distance
+away from the iron bedplate which carries both engine and dynamo;
+otherwise a large proportion of the flux which passes through the
+magnet limbs would leak through the bedplate across from pole
+to pole without passing through the armature core, and so would not
+be cut by the armature wires.</p>
+
+<table class="flt" style="float: left; width: 270px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:219px; height:155px" src="images/img773c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 26.</span></td></tr></table>
+
+<p>Next may be placed the &ldquo;Manchester&rdquo; field (fig. 26)&mdash;the type
+of a divided magnetic circuit in which the flux forming one field or
+pole is divided between two magnets. An exciting coil is placed
+on each half of the double horse-shoe magnet, the pair being so
+wound that consequent poles are formed above and below the
+armature. Each magnet thus carries one-half of the total flux, the
+lines of the two halves uniting to
+form a common field where they issue
+forth into or leave the air-gaps. The
+pole-pieces may be lighter than in the
+single horse-shoe type, and the field
+is much more symmetrical, whence it
+is well suited to ring armatures of
+large diameter. Yet these advantages
+are greatly discounted by the excessive
+magnetic leakage, and by the increased
+weight of copper in the exciting coils.
+Even if the greater percentage which
+the leakage lines bear to the useful flux is neglected, and the cross
+sectional area of each magnet core is but half that of the equivalent
+single horse-shoe, the weight of wire in the double magnet for the
+same rise of temperature in the coils must be some 40% more than
+in the single horse-shoe, and the rate at which energy is expended
+in heating the coils will exceed that of the single horse-shoe in the
+same proportion.</p>
+
+<p>Thirdly comes the two-pole <i>ironclad</i> type, so called from the
+exciting coil being more or less encased by the iron yoke; this latter
+is divided into two halves, which pass on either side of the armature.
+Unless the yoke be kept well away from the polar edges and armature,
+the leakage across the air into the yoke becomes considerable,
+especially if only one exciting coil is used, as in fig. 27 <span class="scs">A</span>; it is better,
+therefore, to divide the excitation between two coils, as in fig. 27 <span class="scs">B</span>,
+when the field also becomes symmetrical.</p>
+
+<p>From this form is easily derived the <i>multipolar</i> type of fig. 28 or
+fig. 29, which is by far the most usual for any number of poles from
+four upwards; its leakage coefficient is but small, and it is economical
+in weight both of iron and copper.</p>
+
+<table class="flt" style="float: right; width: 390px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:326px; height:199px" src="images/img774a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 27.</span></td></tr></table>
+
+<p>As regards the materials of which magnets are made, generally
+speaking there is little difference in the permeability of &ldquo;wrought
+iron&rdquo; or &ldquo;mild steel forgings&rdquo; and good &ldquo;cast steel&rdquo;; typical
+<span class="pagenum"><a name="page774" id="page774"></a>774</span>
+<span class="sidenote">Materials of magnets.</span>
+(B, H) curves connecting the magnetizing force required with different
+flux-densities for these materials are given under <span class="sc"><a href="#artlinks">Electromagnetism</a></span>.
+On the other hand there is a marked inferiority in the
+case of &ldquo;cast iron,&rdquo; which for a flux-density of B =
+8000 C.G.S. lines per sq. cm. requires practically the
+same number of ampere-turns per centimetre length as steel requires
+for B = 16,000. Whatever the material, if the flux-density be pressed
+to a high value the ampere-turns are very largely increased owing to
+its approaching saturation, and this implies either a large amount
+of copper in the field coils or an undue expenditure of electrical
+energy in their excitation. Hence there is a limit imposed by
+practical considerations to the density at which the magnet should
+be worked, and this limit may be placed at about B = 16,000 for
+wrought iron or steel, and at half this value for cast iron. For
+a given flux, therefore, the cast iron magnet must have twice the
+sectional area and be twice as heavy, although this disadvantage
+is partly compensated
+by its greater cheapness.
+If, however, cast
+iron be used for the
+portion of the magnetic
+circuit which is covered
+with the exciting coils,
+the further disadvantage
+must be added
+that the weight of copper
+on the field-magnet
+is much increased, so
+that it is usual to employ
+forgings or cast
+steel for the magnet
+cores on which the coils are wound. If weight is not a disadvantage,
+a cast iron yoke may be combined with the wrought iron or cast
+steel magnet cores. An absence of joints in the magnetic circuit
+is only desirable from the point of view of economy of expense in
+machining the component parts during manufacture; when the
+surfaces which abut against each other are drawn firmly together
+by screws, the want of homogeneity at the joint, which virtually
+amounts to the presence of a very thin film of air, produces little
+or no effect on the total reluctance by comparison with the very
+much longer air-gaps surrounding the armature. In order to reduce
+the eddy-currents in the pole-pieces, due to the use of toothed
+armatures with relatively wide slots, the poles themselves must be
+laminated, or must have fixed to them laminated pole-shoes, built
+up of thin strips of mild steel riveted together (as shown in fig. 29).</p>
+
+<table class="flt" style="float: left; width: 256px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:206px; height:214px" src="images/img774b.jpg" alt="" /></td></tr>
+<tr><td class="caption1"><span class="sc">Fig. 28.</span></td></tr></table>
+
+<p>However it be built up, the mechanical strength of the magnet
+system must be carefully considered. Any two surfaces between
+which there exists a field of density B<span class="su">g</span> experience a force tending
+to draw them together proportional to the square of the density,
+and having a value of B<span class="su">g</span>² / (1.735 × 10<span class="su">6</span>) &#8468; per sq. in. of surface,
+over which the density may be regarded as having the uniform
+value B<span class="su">g</span>. Hence, quite apart from the torque with which the
+stationary part of the dynamo tends to
+turn with the rotating part as soon as
+current is taken out of the armature,
+there exists a force tending to make the
+pole-pieces close on the armature as soon
+as the field is excited. Since both armature
+and magnet must be capable of
+resisting this force, they require to be
+rigidly held; although the one or the other
+must be capable of rotation, there should
+otherwise be no possibility of one part of
+the magnetic circuit shifting relatively
+to any other part. An important conclusion
+may be drawn from this circumstance.
+If the armature be placed
+exactly concentric within the bore of the poles, and the two or
+more magnetic fields be symmetrical about a line joining their
+centres, there is no tendency for the armature core to be drawn in
+one direction more than in another; but if there is any difference
+between the densities of the several fields, it will cause an unbalanced
+stress on the armature and its shaft, under which it will bend, and
+as this bending is continually reversed relatively to the fibres of the
+shaft, they will eventually become weakened and give way. Especially
+is this likely to take place in dynamos with short air-gaps,
+wherein any difference in the lengths of the air-gaps produces a
+much greater percentage difference in the flux-density than in
+dynamos with long air-gaps. In toothed armatures with short
+air-gaps the shaft must on this account be sufficiently strong to
+withstand the stress without appreciable bending.</p>
+</div>
+
+<p>Reference has already been made to the importance in dynamo
+design of the <i>predetermination of the flux</i> due to a given number
+of ampere-turns wound on the field-magnet, or, conversely,
+of the number of ampere-turns which must
+<span class="sidenote">The magnetic circuit.</span>
+be furnished by the exciting coils in order that a certain
+flux corresponding to one field may flow through the
+armature core from each pole. An equally important problem
+is the correct proportioning of the field-magnet, so that the
+useful flux Z<span class="su">a</span> may be obtained with the greatest economy in
+materials and exciting energy. The key to the two problems is
+to be found in the concept of a magnetic circuit as originated by
+H.A. Rowland and R.H.M. Bosanquet;<a name="fa16p" id="fa16p" href="#ft16p"><span class="sp">16</span></a> and the full solution
+of both may be especially connected with the name of Dr J.
+Hopkinson, from his practical application of the concept in his
+design of the Edison-Hopkinson machine, and in his paper on
+&ldquo;Dynamo-Electric Machinery.&rdquo;<a name="fa17p" id="fa17p" href="#ft17p"><span class="sp">17</span></a> The publication of this paper
+in 1886 begins the second era in the history of the dynamo;
+it at once raised its design from the level of empirical rules-of-thumb
+to a science, and is thus worthy to be ranked as the
+necessary supplement of the original discoveries of Faraday.
+The process of predetermining the necessary ampere-turns is
+described in a simple case under <span class="sc"><a href="#artlinks">Electromagnetism</a></span>. In its
+extension to the complete dynamo, it consists merely in the
+division of the magnetic circuit into such portions as have the
+same sectional area and permeability and carry approximately
+the same total flux; the difference of magnetic potential that
+must exist between the ends of each section of the magnet in
+order that the flux may pass through it is then calculated
+<i>seriatim</i> for the several portions into which the magnetic circuit
+is divided, and the separate items are summed up into one
+magnetomotive force that must be furnished by the exciting
+coils.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:517px; height:316px" src="images/img774c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 29.</span></td></tr></table>
+
+<div class="condensed">
+<p>The chief sections of the magnetic circuit are (1) the air-gaps,
+(2) the armature core, and (3) the iron magnet.</p>
+
+<p>The <i>air-gap</i> of a dynamo with smooth-core armature is partly
+filled with copper and partly with the cotton, mica, or other materials
+used to insulate the core and wires; all these substances are, however,
+sensibly non-magnetic, so that the whole interferric gap
+between the iron of the pole-pieces and the iron of the armature
+may be treated as an air-space, of which the permeability is constant
+for all values of the flux density, and in the C.G.S. system is unity.
+Hence if l<span class="su">g</span> and A<span class="su">g</span> be the length and area of the single air-gap in cm.
+and sq. cm., the reluctance of the double air-gap is 2l<span class="su">g</span> / A<span class="su">g</span>, and the
+difference of magnetic potential required to pass Z<span class="su">a</span> lines over this
+reluctance is Z<span class="su">a</span>·2l<span class="su">g</span> / A<span class="su">g</span> = B<span class="su">g</span>·2l<span class="su">g</span>; or, since one ampere-turn gives
+1.257 C.G.S. units of magnetomotive force, the exciting power in
+ampere-turns required over the two air-gaps is X<span class="su">g</span> = B<span class="su">g</span>·2l<span class="su">g</span> / 1.257 =
+0.8B<span class="su">g</span>·2l<span class="su">g</span>. In the determination of the area A<span class="su">g</span> small allowance
+must be made for the fringe of lines which extend beyond the actual
+polar face. In the toothed armature with open slots, the lines are
+no longer uniformly distributed over the air-gap area, but are
+graduated into alternate bands of dense and weak induction corresponding
+to the teeth and slots. Further, the lines curve round into
+the sides of the teeth, so that their average length of path in the
+air and the air-gap reluctance is not so easily calculated. Allowance
+must be made for this by taking an increased length of air-gap
+= ml<span class="su">g</span>, where m is the ratio <i>maximum density/mean density</i>, of which
+the value is chiefly determined by the ratios of the width of tooth
+to width of slot and of the width of slot to the air-gap between
+pole-face and surface of the armature core.</p>
+
+<p><span class="pagenum"><a name="page775" id="page775"></a>775</span></p>
+
+<p>The <i>armature core</i> must be divided into the teeth and the core
+proper below the teeth. Owing to the tapering section of the teeth,
+the density rises towards their root, and when this reaches a high
+value, such as 18,000 or more lines per sq. cm., the saturation of
+the iron again forces an increasing proportion of the lines outwards
+into the slot. A distinction must then be drawn between the
+&ldquo;apparent&rdquo; induction which would hold if all the lines were concentrated
+in the teeth, and the &ldquo;real&rdquo; induction. The area of the
+iron is obtained by multiplying the number of teeth under the pole-face
+by their width and by the net length of the iron core parallel
+to the axis of rotation. The latter is the gross length of the armature
+less the space lost through the insulating varnish or paper between
+the disks or through the presence of ventilating ducts, which are
+introduced at intervals along the length of the core. The former
+deduction averages about 7 to 10% of the gross length, while the
+latter, especially in large multipolar machines, is an even more
+important item. Alter calculating the density at different sections
+of the teeth, reference has now to be made to a (B, H) or flux-density
+curve, from which may be found the number of ampere-turns
+required per cm. length of path. This number may be expressed
+as a function of the density in the teeth, and &fnof;(B<span class="su">t</span>) be its average
+value over the length of a tooth, the ampere-turns of excitation
+required over the teeth on either side of the core as the lines of one
+field enter or leave the armature is X<span class="su">t</span> = &fnof;(B<span class="su">t</span>)·2l<span class="su">t</span>, where l<span class="su">t</span> is the
+length of a single tooth in cm.</p>
+
+<p>In the core proper below the teeth the length of path continually
+shortens as we pass from the middle of the pole towards the centre
+line of symmetry. On the other hand, as the lines gradually accumulate
+in the core, their density increases from zero midway under the
+poles until it reaches a maximum on the line of symmetry. The
+two effects partially counteract one another, and tend to equalize
+the difference of magnetic potential required over the paths of
+varying lengths; but since the reluctivity of the iron increases
+more rapidly than the density of the lines, we may approximately
+take for the length of path (l<span class="su">a</span>) the minimum peripheral distance
+between the edges of adjacent pole-faces, and then assume the
+maximum value of the density of the lines as holding throughout
+this entire path. In ring and drum machines the flux issuing from
+one pole divides into two halves in the armature core, so that the
+maximum density of lines in the armature is B<span class="su">a</span> = Z<span class="su">a</span> / 2ab, where a =
+the radial depth of the disks in centimetres and b = the net length of
+iron core. The total exciting power required between the pole-pieces
+is therefore, at no load, X<span class="su">p</span> = X<span class="su">g</span> + X<span class="su">t</span> + X<span class="su">a</span>, where X<span class="su">a</span> =
+&fnof;(B<span class="su">a</span>)·l<span class="su">a</span>; in order, however, to allow for the effect of the armature
+current, which increases with the load, a further term X<span class="su">b</span>, must be
+added.</p>
+
+<table class="flt" style="float: right; width: 290px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:236px; height:171px" src="images/img775a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 30.</td></tr></table>
+
+<p>In the continuous-current dynamo it may be, and usually is,
+necessary to move the brushes forward from the interpolar line of
+symmetry through a small angle in the direction of rotation, in
+order to avoid sparking between the brushes and the commutator
+(<i>vide infra</i>). When the dynamo is giving current, the wires on
+either side of the diameter of commutation form a current-sheet
+flowing along the surface of the armature from end to end, and
+whatever the actual end-connexions of the wires, the wires may be
+imagined to be joined together into a system of loops such that the
+two sides of each loop are carrying current in opposite directions.
+Thus a number of armature ampere-turns are formed, and their
+effect on the entire system of magnet and armature must be taken
+into account. So long as the diameter of commutation coincides
+with the line of symmetry, the armature may be regarded as a
+cylindrical electromagnet producing a flux of lines, as shown in
+fig. 30. The direction of the self-induced flux in the air-gaps is
+the same as that of the lines of the external field in one quadrant
+on one side of DC, but opposed to it in the other quadrant on the
+same side of DC; hence in the
+resultant field due to the combined
+action of the field-magnet and
+armature ampere-turns, the flux is
+as much strengthened over the one
+half of each polar face as it is
+weakened over the other, and the
+total number of lines is unaffected,
+although their distribution is
+altered. The armature ampere-turns
+are then called <i>cross-turns</i>,
+since they produce a cross-field,
+which, when combined with the symmetrical
+field, causes the leading
+pole-corners <i>ll</i> to be weakened and the trailing pole-corners tt to be
+strengthened, the neutral line of zero field being thus twisted forwards
+in the direction of rotation. But when the brushes and diameter of
+commutation are shifted forward, as shown in fig. 31, it will be seen
+that a number of ampere-turns, forming a zone between the lines
+D<i>n</i> and <i>m</i>C, are in effect wound immediately on the magnetic circuit
+proper, and this belt of ampere-turns is in direct opposition to the
+ampere-turns of the field, as shown by the dotted and crossed wires
+on the pole-pieces. The armature ampere-turns are then divisible
+into the two bands, the <i>back-turns</i>, included within twice the angle
+of lead &lambda;, weakening the field, and the cross-turns, bounded by the
+lines Dm, nC, again producing distortion of the weakened symmetrical
+field. If, therefore, a certain flux is to be passed through
+the armature core in opposition to the demagnetizing turns, the
+difference of magnetic potential between the pole-faces must include
+not only X<span class="su">a</span>, X<span class="su">t</span>, and X<span class="su">g</span>, but also an item X<span class="su">b</span>, in order to balance the
+&ldquo;back&rdquo; ampere-turns of the armature. The amount by which
+the brushes must be shifted forward increases with the armature
+current, and in corresponding proportion the back ampere-turns
+are also increased, their value being c&tau;2&lambda; / 360°, where c = the current
+carried by each of the &tau; active wires. Thus the term X<span class="su">b</span>, takes into
+account the effect of the armature reaction on the total flux; it
+varies as the armature current and angle of lead required to avoid
+sparking are increased; and the reason for its introduction in the
+fourth place (X<span class="su">p</span> = X<span class="su">g</span> + X<span class="su">t</span> + X<span class="su">a</span> + X<span class="su">b</span>), is that it increases the magnetic
+difference of potential which
+must exist between the poles of the
+dynamo, and to which the greater
+part of the leakage is due. The
+leakage paths which are in parallel
+with the armature across the poles
+must now be estimated, and so a new
+value be derived for the flux at the
+commencement of the <i>iron-magnet</i>
+path. If P = their joint permeance,
+the leakage flux due to the difference
+of potential at the poles is
+z<span class="su">l</span> = 1.257X<span class="su">p</span> × P, and this must be added to the useful flux
+Z<span class="su">a</span>, or Z<span class="su">p</span> = Z<span class="su">a</span> + Z<span class="su">l</span>. There are also certain leakage paths in
+parallel with the magnet cores, and upon the permeance of these
+a varying number of ampere-turns is acting as we proceed along
+the magnet coils; the magnet flux therefore increases by the addition
+of leakage along the length of the limbs, and finally reaches
+a maximum near the yoke. Either, then, the density in the magnet
+B<span class="su">m</span> = Z<span class="su">m</span> / A<span class="su">m</span> will vary if the same sectional area be retained throughout,
+or the sectional area of the magnet must itself be progressively
+increased. In general, sufficient accuracy will be obtained by
+assuming a certain number of additional leakage lines z<span class="su">n</span> as traversing
+the entire length of magnet limbs and yoke (= l<span class="su">m</span>), so that the
+density in the magnet has the uniform value B<span class="su">m</span> = (Z<span class="su">p</span> + z<span class="su">n</span>) / A<span class="su">m</span>.
+The leakage flux added on actually within the length of the magnet
+core or z<span class="su">n</span> will be approximately equal to half the total M.M.F. of
+the coils multiplied by the permeance of the leakage paths around
+one coil. The corresponding value of H can then be obtained from
+the (B, H) curve of the material of which the magnet is composed,
+and the ampere-turns thus determined must be added to X<span class="su">p</span>, or
+X = X<span class="su">p</span> + X<span class="su">m</span>, where X<span class="su">m</span> = &fnof;(B<span class="su">m</span>)l<span class="su">m</span>. The final equation for the exciting
+power required on a magnetic circuit as a whole will therefore
+take the form</p>
+
+<p class="center">X = AT = 0.8B<span class="su">g</span>·2l<span class="su">g</span> + &fnof;(B<span class="su">t</span>) 2l<span class="su">t</span> + &fnof;(B<span class="su">a</span>) l<span class="su">a</span> + X<span class="su">b</span> + &fnof;(B<span class="su">m</span>) l<span class="su">m</span>.</p>
+<div class="author">(3)</div>
+
+<table class="flt" style="float: right; width: 275px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:225px; height:151px" src="images/img775b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 31.</span></td></tr></table>
+
+<p>If the magnet cores are of wrought iron or cast steel, and the yoke
+is of cast iron, the last term must be divided into two portions
+corresponding to the different materials, <i>i.e.</i> into f(B<span class="su">m</span>)l<span class="su">m</span> + f(B<span class="su">y</span>)l<span class="su">y</span>.
+In the ordinary multipolar machine with as many magnet-coils as
+there are poles, each coil must furnish half the above number of
+ampere-turns.</p>
+
+<p>Since no substance is impermeable to the passage of magnetic flux,
+the only form of magnetic circuit free from leakage is one uniformly
+wound with ampere-turns over its whole length. The
+reduction of the <i>magnetic leakage</i> to a minimum in any
+<span class="sidenote">Magnetic leakage.</span>
+given type is therefore primarily a question of distributing
+the winding as far as possible uniformly upon the circuit, and
+as the winding must be more or less concentrated into coils, it resolves
+itself into the necessity of introducing as long air-paths as possible
+between any surfaces which are at different magnetic potentials.
+No iron should be brought near the machine which does not form
+part of the magnetic circuit proper, and especially no iron should be
+brought near the poles, between which the difference of magnetic
+potential practically reaches its maximum value. In default of a
+machine of the same size or similar type on which to experiment,
+the probable direction of the leakage flux must be assumed from
+the drawing, and the air surrounding the machine must be mapped
+out into areas, between which the permeances are calculated as
+closely as possible by means of such approximate formulae as those
+devised by Professor G. Forbes.</p>
+
+<p>In the earliest &ldquo;magneto-electric&rdquo; machines permanent steel
+magnets, either simple or compound, were employed, and for many
+years these were retained in certain alternators, some
+of which are still in use for arc lighting in lighthouses.
+<span class="sidenote">Excitation of field-magnet.</span>
+But since the field they furnish is very weak, a great
+advance was made when they were replaced by soft
+iron electromagnets, which could be made to yield a much more
+intense flux. As early as 1831 Faraday<a name="fa18p" id="fa18p" href="#ft18p"><span class="sp">18</span></a> experimented with electromagnets,
+and after 1850 they gradually superseded the permanent
+magnet. When the total ampere-turns required to excite the
+electromagnet have been determined, it remains to decide how
+the excitation shall be obtained; and, according to the method
+<span class="pagenum"><a name="page776" id="page776"></a>776</span>
+adopted, continuous-current machines may be divided into four
+well-defined classes.</p>
+
+<table class="flt" style="float: right; width: 300px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:253px; height:245px" src="images/img776a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 32.</span></td></tr></table>
+
+<p>The simplest method, and that which was first used, is <i>separate
+excitation</i> from some other source of direct current, which may
+be either a primary or a secondary battery or another dynamo
+(fig. 32). But since the armature yields a continuous current, it
+was early suggested (by J. Brett in 1848 and F. Sinsteden in 1851)
+that this current might be utilized to increase the flux; combinations
+of permanent and electromagnets were therefore next employed,
+acting either on the main armature or on separate armatures, until
+in 1867 Dr Werner von Siemens
+and Sir C. Wheatstone almost
+simultaneously discovered that
+the dynamo could be made <i>self-exciting</i>
+through the residual
+magnetism retained in the soft
+iron cores of the electromagnet.
+The former proposed to take the
+whole of the current round the
+magnet coils which were in series
+with the armature and external
+circuit, while the latter proposed
+to utilize only a portion derived
+by a shunt from the main circuit;
+we thus arrive at the
+second and third classes, namely,
+<i>series</i> and <i>shunt</i> machines. The
+starting of the process of excitation
+in either case is the
+same; when the brushes are touching the commutator and the
+armature is rotated, the small amount of flux left in the magnet
+is cut by the wires, and a very small current begins to flow round
+the closed circuit; this increases the flux, which in turn further
+increases the E.M.F. and current, until, finally, the cumulative effect
+stops through the increasing saturation of the iron cores. Fig. 33,
+illustrating the <i>series</i> machine, shows the winding of the exciting
+coils to be composed of a few turns of thick wire. Since the current
+is undivided throughout the whole circuit, the resistance of both the
+armature and field-magnet winding must be low as compared with
+that of the external circuit, if the useful power available at the
+terminals of the machine is to form a large percentage of the total
+electrical power&mdash;in other words, if the efficiency is to be high.
+Fig. 34 shows the third method, in which the winding of the field-magnets
+is a <i>shunt</i> or fine-wire circuit of many turns applied to the
+terminals of the machine; in this ease the resistance of the shunt
+must be high as compared with that of the external circuit, in order
+that only a small proportion of the total energy may be absorbed
+in the field.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter" colspan="2"><img style="width:491px; height:234px" src="images/img776b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 33.</span></td>
+<td class="caption"><span class="sc">Fig. 34.</span></td></tr></table>
+
+<p>Since the whole of the armature current passes round the field-magnet
+of the series machine, any alteration in the resistance of
+the external circuit will affect the excitation and also the voltage.
+A curve connecting together corresponding values of external
+current and terminal voltage for a given speed of rotation is known
+as the <i>external-characteristic</i> of the machine; in its main features
+it has the same appearance as a curve of magnetic flux, but when
+the current exceeds a certain amount it begins to bend downwards
+and the voltage decreases. The reason for this will be found in
+the armature reaction at large loads, which gradually produces a
+more and more powerful demagnetizing effect, as the brushes are
+shifted forwards to avoid sparking; eventually the back ampere-turns
+overpower any addition to the field that would otherwise
+be due to the increased current flowing round the magnet. The
+&ldquo;external characteristic&rdquo; for a shunt machine has an entirely
+different shape. The field-magnet circuit being connected in
+parallel with the external circuit, the exciting current, if the applied
+voltage remains the same, is in no way affected by alterations in the
+resistance of the latter. As, however, an increase in the external
+current causes a greater loss of volts in the armature and a greater
+armature reaction, the terminal voltage, which is also the exciting
+voltage, is highest at no load and then diminishes. The fall is at
+first gradual, but after a certain critical value of the armature
+current is reached, the machine is rapidly demagnetized and loses
+its voltage entirely.</p>
+
+<table class="flt" style="float: right; width: 250px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:201px; height:230px" src="images/img776c.jpg" alt="" /></td></tr>
+<tr><td class="caption1"><span class="sc">Fig.</span> 35.</td></tr></table>
+
+<p>The last method of excitation, namely, <i>compound-winding</i> (fig. 35),
+is a combination of the two preceding, and was first used by S.A.
+Varley and by C.F. Brush. If a machine is in the first instance shunt-wound,
+and a certain number of series-turns are added, the latter, since
+they carry the external current, can be made to counteract the effect
+which the increased external current
+would have in lowering the voltage
+of the simple shunt machine. The
+ampere-turns of the series winding
+must be such that they not only
+balance the increase of the demagnetizing
+back ampere-turns on the
+armature, but further increase the
+useful flux, and compensate for the
+loss of volts over their own resistance
+and that of the armature. The machine
+will then give for a constant speed
+a nearly constant voltage at its terminals,
+and the curve of the external
+characteristic becomes a straight line
+for all loads within its capacity. Since
+with most prime movers an increase of
+the load is accompanied by a drop in
+speed, this effect may also be counteracted; while, lastly, if the
+series-turns are still further increased, the voltage may be made to
+rise with an increasing load, and the machine is &ldquo;over-compounded.&rdquo;</p>
+</div>
+
+<p>At the initial moment when an armature coil is first short-circuited
+by the passage of the two sectors forming its ends under
+the contact surface of a brush, a certain amount of
+electromagnetic energy is stored up in its magnetic
+<span class="sidenote">Commutation and sparking at the brushes.</span>
+field as linked with the ampere-turns of the coil when
+carrying its full share of the total armature current.
+During the period of short-circuit this quantity of
+energy has to be dissipated as the current falls to zero,
+and has again to be re-stored as the current is reversed and raised
+to the same value, but in the opposite direction. The period
+of short-circuit as fixed by the widths of the brush and of the
+mica insulation between the sectors, and by the peripheral
+speed of the commutator is extremely brief, and only lasts on
+an average from <span class="spp">1</span>&frasl;<span class="suu">200</span>th to <span class="spp">1</span>&frasl;<span class="suu">1000</span>th of a second. The problem of
+sparkless commutation is therefore primarily a question of our
+ability to dissipate and to re-store the required amount of energy
+with sufficient rapidity.</p>
+
+<p>An important aid towards the solution of this problem is
+found in the effect of the varying contact-resistance between
+the brush and the surfaces of the leading and trailing sectors
+which it covers. As the commutator moves under the brush,
+the area of contact which the brush makes with the leading
+sector diminishes, and the resistance between the two rises;
+conversely, the area of contact between the brush and the trailing
+sector increases and the resistance falls. This action tends
+automatically to bring the current through each sector into
+strict proportionality to the amount of its surface which is
+covered by the brush, and so to keep the current-density and
+the loss of volts over the contacts uniform and constant. As
+soon as the current-density in the two portions of the brush
+becomes unequal, a greater amount of heat is developed at the
+commutator surface, and this in the first place affords an additional
+outlet for the dissipation of the stored energy of the coil,
+while after reversal of the current it is the accompaniment of
+a re-storage of the required energy. This energy, as well as
+that which is spent in heating the coil, can in fact, in default of
+other sources, be derived through the action of the unequal
+current-density from the electrical output of the rest of the
+armature winding, and so only indirectly from the prime mover.</p>
+
+<p>In practice, when the normal contact-resistance of the brushes
+is low relatively to the resistance of the coil, as is the case with
+metal brushes of copper or brass gauze, but little benefit can be
+obtained from the action of the varying contact-resistance. It
+exerts no appreciable effect until close towards the end of the
+period of short-circuit, and then only with such a high-current-density
+at the trailing edge of the leaving sector that at the
+moment of parting the brush-tip is fused, or its metal volatilized,
+and sparking has in fact set in. With such brushes, then, it
+becomes necessary to call in the aid of a reversing E.M.F.
+impressed upon the coil by the magnetic field through which
+it is moving. If such a reversing field comes into action while
+<span class="pagenum"><a name="page777" id="page777"></a>777</span>
+the current is still unreversed, its E.M.F. is opposed to the
+direction of the current, and the coil is therefore driving the
+armature forward as in a motor; it thus affords a ready means
+of rapidly dissipating part of the initial energy in the form of
+mechanical work instead of as heat. After the current has
+been reversed, the converse process sets in, and the prime
+mover directly expends mechanical energy not only in heating
+the coil, but also in storing up electromagnetic energy with a
+rapidity dependent upon the strength of the reversing field.
+The required direction of external field can be obtained in the
+dynamo by shifting the brushes forward, so that the short-circuited
+coil enters into the fringe of lines issuing from the
+leading pole-tip, <i>i.e.</i> by giving the brushes an &ldquo;angle of lead.&rdquo;
+An objection to this process is that the main flux is thereby
+weakened owing to the belt of back ampere-turns which arises
+(<i>v. supra</i>). A still greater objection is that the amount of the
+angle of lead must be suited to the value of the load, the corrective
+power of copper brushes being very small if the reversing
+E.M.F. is not closely adjusted in proportion to the armature
+current.</p>
+
+<p>On this account metal brushes have been almost entirely
+superseded by carbon moulded into hard blocks. With these,
+owing to their higher specific contact-resistance, a very considerable
+reversing effect can be obtained through the action of
+unequal current-density, and indeed in favourable cases complete
+sparklessness can be obtained throughout the entire range of
+load of the machine with a fixed position of the brushes. Yet
+if the work which they are called upon to perform exceeds certain
+limits, they tend to become overheated with consequent glowing
+or sparking at their tips, so that, wherever possible, it is advisable
+to reinforce their action by a certain amount of reversing field,
+the brushes being set so that its strength is roughly correct for,
+say, half load.</p>
+
+<p>In the case of dynamos driven by steam-turbines, sparkless
+commutation is especially difficult to obtain owing to the high
+speed of rotation and the very short space of time in which the
+current has to be reversed. Special &ldquo;reversing poles&rdquo; then
+become necessary; these are wound with magnetizing coils in
+series with the main armature current, so that the strength of
+field which they yield is roughly proportional to the current
+which has to be reversed. These again may be combined with
+a &ldquo;compensating winding&rdquo; embedded in the pole-faces and
+carrying current in the opposite direction to the armature
+ampere-turns, so as to neutralize the cross effect of the latter
+and prevent distortion of the resultant field.</p>
+
+<div class="condensed">
+<p>From the moment that a dynamo begins to run with excited
+field, heat is continuously generated by the passage of the current
+through the windings of the field-magnet coils and the
+armature, as well as by the action of hysteresis and
+<span class="sidenote">Heating effects.</span>
+eddy currents in the armature and pole-pieces. Whether
+the source of the heat be in the field-magnet or in the armature, the
+mass in which it originates will continue to rise in temperature
+until such a difference of temperature is established between itself
+and the surrounding air that the rate at which the heat is carried
+off by radiation, convection and conduction is equal to the rate at
+which it is being generated. Evidently, then, the temperature
+which any part of the machine attains after a prolonged run must
+depend on the extent and effectiveness of the cooling surface from
+which radiation takes place, upon the presence or absence of any
+currents of air set up by the rotation of itself or surrounding parts,
+and upon the presence of neighbouring masses of metal to carry
+away the heat by conduction. In the field-magnet coils the rate
+at which heat is being generated is easily determined, since it is equal
+to the square of the current passing through them multiplied by
+their resistance. Further, the magnet is usually stationary, and
+only indirectly affected by draughts of air due to the rotating armature.
+Hence for machines of a given type and of similar proportions,
+it is not difficult to decide upon some method of reckoning the cooling
+surface of the magnet coils S<span class="su">c</span>, such that the rise of temperature
+above that of the surrounding air may be predicted from an equation
+of the form <i>t° = kW / S<span class="su">c</span></i>, where W = the rate in watts at which heat
+is generated in the coils, and k is some constant depending upon the
+exact method of reckoning their cooling surface. As a general rule
+the cooling surface of a field-coil is reckoned as equal to the exposed
+outer surface of its wire, the influence of the end flanges being
+neglected, or only taken into account in the case of very short
+bobbins wound with a considerable depth of wire. In the case of
+the rotating armature a similar formula must be constructed, but
+with the addition of a factor to allow for the increase in the effectiveness
+of any given cooling surface due to the rotation causing convection
+currents in the surrounding air. Only experiment can
+determine the exact effect of this, and even with a given type of
+armature it is dependent on the number of poles, each of which helps
+to break up the air-currents, and so to dissipate the heat. For
+example, in two-pole machines with drum bar-armatures, if the cooling
+surface be reckoned as equal to the cylindrical exterior plus the
+area of the two ends, the heating coefficient for a peripheral speed of
+1500 ft. per minute is less than half of that for the same armature
+when at rest. A further difficulty still meets the designer in the
+correct predetermination of the total loss of watts in an armature
+before the machine has been tested. It is made up of three separate
+items, namely, the copper loss in the armature winding, the loss
+by hysteresis in the iron, and the loss by eddy currents, which
+again may be divided into those in the armature bars and end-connexions,
+and those in the core and its end-plates. The two
+latter items are both dependent upon the speed of the machine;
+but whereas the hysteresis loss is proportional to the speed for a
+given density of flux in the armature, the eddy current loss is
+proportional to the square of the speed, and owing to this difference,
+the one loss can be separated from the other by testing an
+armature at varying speeds. Thus for a given rise of temperature,
+the question of the amount of current which can be taken out of
+an armature at different speeds depends upon the proportion which
+the hysteresis and eddy watts bear to the copper loss, and the ratio
+in which the effectiveness of the cooling surface is altered by the
+alteration in speed. Experimental data, again, can alone decide
+upon the amount of eddy currents that may be expected in given
+armatures, and caution is required in applying the results of one
+machine to another in which any of the conditions, such as the
+number of poles, density in the teeth, proportions of slot depth to
+width, &amp;c., are radically altered.</p>
+
+<p>It remains to add, that the rise of temperature which may be
+permitted in any part of a dynamo after a prolonged run is very
+generally placed at about 70° Fahr. above the surrounding air.
+Such a limit in ordinary conditions of working leads to a final
+temperature of about 170° Fahr., beyond which the durability of
+the insulation of the wires is liable to be injuriously affected. Upon
+some such basis the output of a dynamo in continuous working is
+rated, although for short periods of, say, two hours the normal full-load
+current of a large machine may be exceeded by some 25%
+without unduly heating the armature.</p>
+</div>
+
+<p>For the electro-deposition of metals or the electrolytic treatment
+of ores a continuous current is a necessity; but, apart from
+such use, the purposes from which the continuous-current
+dynamo is well adapted are so numerous that
+<span class="sidenote">Uses of continuous current dynamos.</span>
+they cover nearly the whole field of electrical engineering,
+with one important exception. To meet these
+various uses, the pressures for which the machine is
+designed are of equally wide range; for the transmission of
+power over long distances they may be as high as 3000 volts,
+and for electrolytic work as low as five. Each electrolytic bath,
+with its leads, requires on an average only some four or five volts,
+so that even when several are worked in series the voltage of the
+dynamo seldom exceeds 60. On the other hand, the current is
+large and may amount to as much as from 1000 to 14,000 amperes,
+necessitating the use of two commutators, one at either end of
+the armature, in order to collect the current without excessive
+heating of the sectors and brushes. The field-magnets are invariably
+shunt-wound, in order to avoid reversal of the current
+through polarization at the electrodes of the bath. For incandescent
+lighting by glow lamps, the requirements of small
+isolated installations and of central stations for the distribution
+of electrical energy over large areas must be distinguished. For
+the lighting of a private house or small factory, the dynamo
+giving from 5 to 100 kilo-watts of output is commonly wound
+for a voltage of 100, and is driven by pulley and belt from a gas,
+oil or steam-engine; or, if approaching the higher limit above
+mentioned, it is often directly coupled to the crank-shaft of the
+steam-engine. If used in conjunction with an accumulator of
+secondary cells, it is shunt-wound, and must give the higher
+voltage necessary to charge the battery; otherwise it is compound-wound,
+in order to maintain the pressure on the lamps
+constant under all loads within its capacity. The compound-wound
+dynamo is likewise the most usual for the lighting of
+steamships, and is then directly coupled to its steam-engine;
+its output seldom exceeds 100 kilo-watts, at a voltage of 100 or
+110. For larger installations a voltage of 250 is commonly used,
+while for central-station work, economy in the distributing
+<span class="pagenum"><a name="page778" id="page778"></a>778</span>
+mains dictates a higher voltage, especially in connexion with
+a three-wire system; the larger dynamos may then give 500
+volts, and be connected directly across the two outer wires. A
+pair of smaller machines coupled together, and each capable of
+giving 250 volts, are often placed in series across the system,
+with their common junction connected to the middle wire; the
+one which at any time is on the side carrying the smaller current
+will act as a motor and drive the other as a dynamo, so as to
+balance the system. The directly-coupled steam dynamo may
+be said to have practically displaced the belt- or rope-driven
+sets which were formerly common in central stations. The
+generating units of the central station are arranged in progressive
+sizes, rising from, it may be, 250 or 500 horse-power up to 750
+or 1000, or in large towns to as much as 5000 horse-power. If
+for lighting only, they are usually shunt-wound, the regulation
+of the voltage, to keep the pressure constant on the distributing
+system under the gradual changes of load, being effected by
+variable resistances in the shunt circuit of the field-magnets.</p>
+
+<p>Generators used for supplying current to electric tramways
+are commonly wound for 500 volts at no load and are over-compounded,
+so that the voltage rises to 550 volts at the maximum
+load, and thus compensates for the loss of volts over the
+transmitting lines. For arc lighting it was formerly usual to
+employ a class of dynamo which, from the nature of its construction,
+was called an &ldquo;open-coil&rdquo; machine, and which gave
+a unidirectional but pulsating current. Of such machines the
+Brush and Thomson-Houston types were very widely used;
+their E.M.F. ranged from 2000 to 3000 volts for working a large
+number of arcs in series, and by means of special regulators their
+current was maintained constant over a wide range of voltage.
+But as their efficiency was low and they could not be applied to
+any other purpose, they have been largely superseded in central
+stations by closed-coil dynamos or alternators, which can also
+be used for incandescent lighting. In cases where the central
+station is situated at some distance from the district to which
+the electric energy is to be supplied, voltages from 1000 to 2000
+are employed, and these are transformed down at certain
+distributing centres by continuous-current transformers (see
+<span class="sc"><a href="#artlinks">Transformers</a></span> and <span class="sc"><a href="#artlinks">Electricity Supply</a></span>). These latter
+machines are in reality motor-driven dynamos, and hence are also
+called <i>motor-generators</i>; the armatures of the motor and
+dynamo are often wound on the same core, with a commutator
+at either end, the one to receive the high-pressure motor current,
+and the other to collect the low-pressure current furnished by
+the dynamo.</p>
+
+<div class="condensed">
+<p>In all large central stations it is necessary that the dynamos
+should be capable of being run <i>in parallel</i>, so that their outputs
+may be combined on the same &ldquo;omnibus bars&rdquo; and thence distributed
+to the network of feeders. With simple shunt-wound
+machines this is easily effected by coupling together terminals of
+like sign when the voltage of the two or more machines are closely
+equal. With compound-wound dynamos not only must the external
+terminals of like sign be coupled together, but the junctions of the
+brush leads with the series winding must be connected by an
+&ldquo;equalizing&rdquo; lead of low resistance; otherwise, should the E.M.F.
+of one machine for any reason fall below the voltage of the omnibus
+bars, there is a danger of its polarity being reversed by a back
+current from the others with which it is in parallel.</p>
+
+<p>Owing to the necessary presence in the continuous-current dynamo
+of the commutator, with its attendant liability to sparking at the
+brushes, and further, owing to the difficulty of insulating the rotating
+armature wires, a pressure of 3000 volts has seldom been exceeded
+in any one continuous-current machine, and has been given above
+as the limiting voltage of the class. If therefore it is required to
+work with higher pressures in order to secure economy in the transmitting
+lines, two or more machines must be coupled <i>in series</i> by
+connecting together terminals which are of unlike sign.<a name="fa19p" id="fa19p" href="#ft19p"><span class="sp">19</span></a> The stress
+of the total voltage may still fall on the insulation of the winding
+from the body of the machine; hence for high-voltage transmission
+of power over very long distances, the continuous-current dynamo
+in certain points yields in convenience to the alternator. In this
+there is no commutator, the armature coils may be stationary and
+can be more thoroughly insulated, while further, if it be thought
+undesirable to design the machine for the full transmitting voltage,
+it is easy to wind the armature for a low pressure; this can be
+subsequently transformed up to a high pressure by means of the
+alternating-current transformer, which has stationary windings
+and so high an efficiency that but little loss arises from its use.
+With these remarks, the transition may be made to the fuller
+discussion of the alternator.</p>
+</div>
+
+<p class="pt2 center"><i>Alternators.</i></p>
+
+<p>The frequency employed in alternating-current systems for
+distributing power and light varies between such wide limits
+as 25 and 133; yet in recent times the tendency
+has been towards standard frequencies of 25, 50
+<span class="sidenote">Frequency.</span>
+and 100 as a maximum. High frequencies involve more
+copper in the magnet coils, owing to the greater number of poles,
+and a greater loss of power in their excitation, but the alternator
+as a whole is somewhat lighter, and the transformers are cheaper.
+On the other hand, high frequency may cause prejudicial effects,
+due to the inductance and capacity of the distributing lines;
+and in asynchronous motors used on polyphase systems the
+increased number of poles necessary to obtain reasonable speeds
+reduces their efficiency, and is otherwise disadvantageous,
+especially for small horse-powers. A frequency lower than 40 is,
+however, not permissible where arc lighting is to form any considerable
+portion of the work and is to be effected by the alternating
+current without rectification, since below this value the
+eye can detect the periodic alteration in the light as the carbons
+alternately cool and become heated. Thus for combined lighting
+and power 50 or 60 are the most usual frequencies; but if the
+system is designed solely or chiefly for the distribution of power,
+a still lower frequency is preferable. On this account 25 was
+selected by the engineers for the Niagara Falls power transmission,
+after careful consideration of the problem, and this
+frequency has since been widely adopted in similar cases.</p>
+
+<p>The most usual type of heteropolar alternator has an internal
+rotating field-magnet system, and an external stationary armature,
+as in fig. 10. The coils of the armature, which
+must for high voltages be heavily insulated, are then
+<span class="sidenote">Alternator construction.</span>
+not subjected to the additional stresses due to centrifugal
+force; and further, the collecting rings which
+must be attached to the rotating portion need only transmit
+the exciting current at a low voltage.</p>
+
+<table class="flt" style="float: right; width: 380px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:329px; height:238px" src="images/img778.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 36.</td></tr></table>
+
+<p>The homopolar machine possesses the advantages that only
+a single exciting coil is required, whatever the number of polar
+projections, and that both the armature and field-magnet coils
+may be stationary. From fig. 8 it will be seen that it is not
+essential that the exciting
+coil should
+revolve with the internal
+magnet, but it
+may be supported
+from the external
+stationary armature
+while still embracing
+the central part of the
+rotor. The E.M.F. is
+set up in the armature
+coils through the
+periodic variation of
+the flux through them
+as the iron projections sweep past, and these latter may
+be likened to a number of &ldquo;keepers,&rdquo; which complete the
+magnetic circuit. From the action of the rotating iron masses
+they may also be considered as the inducing elements or
+&ldquo;inductors,&rdquo; and the homopolar machine is thence also
+known as the &ldquo;inductor alternator.&rdquo; If the end of the
+rotor marked S in fig. 8 is split up into a number of S polar
+projections similar to the N poles, a second set of armature coils
+may be arranged opposite to them, and we obtain an inductor
+<span class="pagenum"><a name="page779" id="page779"></a>779</span>
+alternator with double armature. Or the polar projections at
+the two ends may be staggered, and a single armature winding
+be passed straight through the armature, as in fig. 36, which
+shows at the side the appearance of the revolving inductor with
+its crown of polar projections in one ring opposite to the gaps
+between the polar projections of the other ring. But in spite
+of its advantage of the single stationary exciting coil, the inductor
+alternator has such a high degree of leakage, and the effect
+of armature reaction is so detrimental in it, that the type has
+been gradually abandoned, and a return has been almost universally
+made to the heteropolar alternator with internal poles
+radiating outwards from a circular yoke-ring. The construction
+of a typical machine of this class is illustrated in fig. 37.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:920px; height:424px" src="images/img779.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 37.</td></tr></table>
+
+<p>Since the field-magnet coils rotate, they must be carefully
+designed to withstand centrifugal force, and are best composed
+of flat copper strip wound on edge with thin insulation between
+adjacent layers. The coil is secured by the edges of the pole-shoes
+which overhang the pole and tightly compress the coil
+against the yoke-ring; the only effect from centrifugal force is
+then to compress still further the flat turns of copper against
+the pole-shoes without deformation. The poles are either of
+cast steel of circular or oblong section, bolted to the rim of the
+yoke-ring, or are built up of thin laminations of sheet steel.
+When the peripheral speed is very high, the yoke-ring will be
+of cast steel or may itself be built up of sheet steel laminations,
+this material being reliable and easily tested to ensure its sound
+mechanical strength. If the armature slots are open, the pole-pieces
+will in any case be laminated to reduce the eddy currents
+set up by the variation of the flux-density.</p>
+
+<p>Owing to the great number of poles<a name="fa20p" id="fa20p" href="#ft20p"><span class="sp">20</span></a> of the alternator when
+driven by a reciprocating steam-engine, the diameter of its
+rotor is usually larger and its length less than in the continuous-current
+dynamo of corresponding output. The support of the
+armature core when of large diameter is therefore a more difficult
+problem, since, apart from any magnetic strains to which it
+may be subjected, its own weight tends to deform it. The
+segmental core-disks are usually secured to the internal circumference
+of a circular cast iron frame; the latter has a box section
+of considerable radial depth to give stiffness to it, and the disks
+are tightly clamped between internal flanges, one being a fixed
+part of the frame and the other loose, with transverse bolts
+passing right through from side to side (fig. 37). In order to
+lessen the weight of the structure and its expense in material,
+the cast iron frame has in some cases been entirely dispensed
+with, and braced tie-rods have been used to render the effective
+iron of the armature core-disks self-supporting.</p>
+
+<table class="flt" style="float: right; width: 360px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:309px; height:457px" src="images/img779a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 38.</td></tr></table>
+
+<p>Owing to the high speed of the turbo-alternator, its rotor calls
+for the utmost care in its design to withstand the effect of
+centrifugal force without
+any shifting of the
+exciting coils, and to
+secure a perfect balance.</p>
+
+<p>The appearance of
+the armature of a
+typical three-phase
+alternator is illustrated
+in fig. 38, which shows
+a portion of the lower
+half after removal of
+the field-magnet.</p>
+
+<p>With open slots the
+coils, after being wound
+on formers to the required
+shape, are
+thoroughly impregnated
+with insulating
+compound, dried, and
+after a further wrapping
+with several layers of
+insulating material,
+finally pressed into the
+slots together with a
+sheet of leatheroid or
+flexible micanite. The end-connexions of each group of coils
+of one phase project straight out from the slots or are
+bent upwards alternately with those of the other phases, so
+that they may clear one another (fig. 37). A wooden wedge
+driven into a groove at the top of each slot is often used
+to lock the coil in place. With slots nearly closed at the
+top, the coils are formed by hand by threading the wire
+<span class="pagenum"><a name="page780" id="page780"></a>780</span>
+through tubes of micanite or specially prepared paper lining
+the slots; or with single-turn loops, stout bars of copper of
+U-shape can be driven through the slots and closed by soldered
+connexions at the other end.</p>
+
+<div class="condensed">
+<p>The first experimental determination of the shape of the E.M.F.
+curve of an alternator was made by J. Joubert in 1880. A revolving
+contact-maker charged a condenser with the E.M.F.
+produced by the armature at a particular instant during
+<span class="sidenote">Shape of E.M.F. curve.</span>
+each period. The condenser was discharged through a
+ballistic galvanometer, and from the measured throw the
+instantaneous E.M.F. could be deduced. The contact-maker was
+then shifted through a small angle, and the instantaneous E.M.F.
+at the new position corresponding to a different moment in the period
+was measured; this process was repeated until the E.M.F. curve
+for a complete period could be traced. Various modifications of
+the same principle have since been used, and a form of &ldquo;oscillograph&rdquo;
+(<i>q.v.</i>) has been perfected which is well adapted for the
+purpose of tracing the curves both of E.M.F. and of current. The
+machine on which Joubert carried out his experiments was a Siemens
+disk alternator having no iron in its armature, and it was found that
+the curve of E.M.F. was practically identical with a sine curve.
+The same law has also been found to hold true for a smooth-core
+ring or drum armature, but the presence of the iron core enables
+the armature current to produce greater distorting effect, so that
+the curves under load may vary considerably from their shape at
+no load. In toothed armatures, the broken surface of the core,
+and the still greater reaction from the armature current, may
+produce wide variations from the sine law, the general tendency
+being to give the E.M.F. curve a more peaked form. The great
+convenience of the assumption that the E.M.F. obeys the sine law
+has led to its being very commonly used as the basis for the mathematical
+analysis of alternator problems; but any deductions made
+from this premiss require to be applied with caution if they are
+likely to be modified by a different shape of the curve. Further, the
+same alternator will give widely different curves even of E.M.F.,
+and still more so of current, according to the nature of the external
+circuit to which it is connected. As will be explained later, the phase
+of the current relatively to the E.M.F. depends not only on the inductance
+of the alternator itself, but also upon the inductance and
+capacity of the external circuit, so that the same current will produce
+different effects according to the amount by which it lags or leads.
+The question as to the relative advantages of differently shaped
+E.M.F. curves has led to much discussion, but can only be answered
+by reference to the nature of the work that the alternator has to
+do&mdash;<i>i.e.</i> whether it be arc lighting, motor driving, or incandescent
+lighting through transformers. The shape of the E.M.F. curve is,
+however, of great importance in one respect, since upon it depends
+the ratio of the maximum instantaneous E.M.F. to the effective
+value, and the insulation of the entire circuit, both external and
+internal, must be capable of withstanding the maximum E.M.F.
+While the maximum value of the sine curve is &radic;2 or 1.414 times
+the effective value, the maximum value of a &Lambda; curve is 1.732 times
+the effective value, so that for the same effective E.M.F. the armature
+wires must not only be more heavily insulated than in the continuous-current
+dynamo, but also the more peaked the curve the better
+must be the insulation.</p>
+</div>
+
+<div class="condensed">
+<p>Since an alternating current cannot be used for exciting the
+field-magnet, recourse must be had to some source of a direct
+current. This is usually obtained from a small auxiliary
+continuous-current dynamo, called an <i>exciter</i>, which may
+<span class="sidenote">Excitation.</span>
+be an entirely separate machine, separately driven and
+used for exciting several alternators, or may be driven from the
+alternator itself; in the latter case the armature of the exciter is
+often coupled directly to the rotating shaft of the alternator, while
+its field-magnet is attached to the bed-plate. Although separate
+excitation is the more usual method, the alternator can also be made
+self-exciting if a part or the whole of the alternating current is
+&ldquo;rectified,&rdquo; and thus converted into a direct current.</p>
+</div>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:405px; height:151px" src="images/img780a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 39.</td></tr></table>
+
+<table class="flt" style="float: right; width: 205px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:156px; height:140px" src="images/img780b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 40.</td></tr></table>
+
+<div class="condensed">
+<p>The general idea of the polyphase alternator giving two or more
+E.M.F.&rsquo;s of the same frequency, but displaced in phase, has been
+already described. The several phases may be entirely
+independent, and such was the case with the early polyphase
+<span class="sidenote">Quarter-phase alternators.</span>
+machines of Gramme, who used four independent
+circuits, and also in the large two-phase alternators
+designed by J.E.H. Gordon in 1883. If the phases are
+thus entirely separate, each requires two collector rings and two
+wires to its external circuit, <i>i.e.</i> four in all for two-phase and six
+for three-phase machines. The only advantage of the polyphase
+machine as thus used is that the whole of the surface of the armature
+core may be efficiently covered with winding, and the output
+of the alternator for a given size be thereby increased. It is, however,
+also possible so to interlink the several circuits of the armature
+that the necessary number of transmitting lines to the external
+circuits may be reduced, and also the weight of copper in them for
+a given loss in the transmission.<a name="fa21p" id="fa21p" href="#ft21p"><span class="sp">21</span></a> The condition which obviously
+must be fulfilled, for such interlinking of the phases to be possible,
+is that in the lines which are to meet at any common junction the
+algebraic sum of the instantaneous currents, reckoned as positive
+if away from such junction and as negative if towards it, must be
+zero. Thus if the phases be diagrammatically represented by the
+relative angular position of the coils in fig. 39, the current in the coils
+A and B differs in phase from the current in the coils C and D by
+a quarter of a period or 90°; hence if the two wires <i>b</i> and <i>d</i> be
+replaced by the single wire <i>bd</i>, this third wire will serve as a common
+path for the currents of the two phases either outwards or on their
+return. At any instant the value of the current in the third wire
+must be the vector sum of the two currents in the other wires, and
+if the shape of the curves of instantaneous E.M.F. and current are
+identical, and are assumed to be sinusoidal, the effective value
+of the current in the third wire will be the vector sum of the effective
+values of the currents in the other wires; in other words, if the
+system is balanced, the effective current in the third wire is &radic;2, or 1.414
+times the current in either of the two outer wires. Since the currents
+of the two phases do not reach their maximum values at the same
+time, the sectional area of the third wire need not be twice that of
+the others; in order to secure maximum efficiency by employing
+the same current density in all three wires, it need only be 40%
+greater than that of either of the outer wires. The effective voltage
+between the external leads may in the same way be calculated by
+a vector diagram, and with the above <i>star connexion</i> the voltage
+between the outer pair of wires <i>a</i> and <i>c</i> is &radic;2, or 1.414 times the
+voltage between either of the outer wires
+and the common wire <i>bd</i>. Next, if the four
+coils are joined up into a continuous helix,
+just as in the winding of a continuous-current
+machine, four wires may be attached to
+equidistant points at the opposite ends of
+two diameters at right angles to each other
+(fig. 40). Such a method is known as the
+<i>mesh connexion</i>, and gives a perfectly symmetrical
+four-phase system of distribution.
+Four collecting rings are necessary if the armature
+rotates, and there is no saving in copper in
+the transmitting lines; but the importance of the arrangement lies in
+its use in connexion with rotary converters, in which it is necessary
+that the winding of the armature should form a closed circuit. If
+<i>e</i> = the effective voltage of one phase A, the voltage between any
+pair of adjacent lines in the diagram is <i>e</i>, and between <i>m</i> and <i>o</i> or
+<i>n</i> and <i>p</i> is <i>e</i> &radic;2. The current in any line is the resultant of the
+currents in the two phases connected to it, and its effective value
+is <i>c</i> &radic;2, where <i>c</i> is the current of one phase.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:324px; height:138px" src="images/img780c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 41.</td></tr></table>
+
+<p>When we pass to machines giving three phases differing by
+120°, the same methods of star and mesh connexion find their
+analogies. If the current in coil A (fig. 41) is flowing
+away from the centre, and has its maximum value, the
+<span class="sidenote">Three-phase alternators.</span>
+currents in coils B and C are flowing towards the centre,
+and are each of half the magnitude of the current in A;
+the algebraic sum of the currents is therefore zero, and
+this will also be the case for all other instants. Hence the three
+coils can be united together at the centre, and three external wires
+are alone required. In this star or &ldquo;Y&rdquo; connexion, if <i>e</i> be the
+effective voltage of each phase, or the voltage between any one
+of the three collecting rings and the common connexion, the volts
+between any pair of transmitting lines will be E = <i>e</i> &radic;3 (fig. 41);
+if the load be balanced, the effective current C in each of the three
+lines will be equal, and the total output in watts will be W = 3C<i>e</i> =
+3CE / &radic;3 = 1.732 EC, or 1.732 times the product of the effective
+voltage between the lines and the current in any single line. Next,
+if the three coils are closed upon themselves in a mesh or <i>delta</i>
+fashion (fig. 42), the three transmitting wires may be connected to
+the junctions of the coils (by means of collecting rings if the armature
+rotates). The voltage E between any pair of wires is evidently
+<span class="pagenum"><a name="page781" id="page781"></a>781</span>
+that generated by one phase, and the current in a line wire is the
+resultant of that in two adjacent phases; or in a balanced system,
+if c be the current in each phase, the current in the line wire beyond
+a collecting ring is C = c&radic;3, hence the watts are W = 3cE = 3CE / &radic;3
+= 1.732 EC, as before. Thus any three-phase winding may be
+changed over from the star to the delta connexion, and will then
+give 1.732 times as much current, but only 1/1.732 times the voltage,
+so that the output remains the same.</p>
+
+<table class="flt" style="float: right; width: 170px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:121px; height:121px" src="images/img781.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 42.</span></td></tr></table>
+
+<p>The &ldquo;armature reaction&rdquo; of the alternator, when the term is
+used in its widest sense to cover all the effects of the alternating
+current in the armature as linked with a magnetic circuit
+or circuits, may be divided into three items which are
+<span class="sidenote">Armature reaction in alternators</span>
+different in their origin and consequences. In the first
+place the armature current produces a self-induced flux
+in local circuits independent of the main magnetic circuit,
+as <i>e.g.</i> linked with the ends of the coils as they project outwards
+from the armature core; such lines may be called &ldquo;secondary
+leakage,&rdquo; of which the characteristic feature is that
+its amount is independent of the position of the
+coils relatively to the poles. The alternations of
+this flux give rise to an inductive voltage lagging
+90° behind the phase of the current, and this
+leakage or reactance voltage must be directly
+counterbalanced electrically by an equal component
+in the opposite sense in the voltage from the
+main field. The second and third elements are
+more immediately magnetic and are entirely dependent
+upon the position of the coils in relation to
+the poles and in relation to the phase of the current which they then
+carry. When the side of a drum coil is immediately under the centre
+of a pole, its ampere-turns are cross-magnetizing, <i>i.e.</i> produce a
+distortion of the main flux, displacing its maximum density to one
+or other edge of the pole. When the coil-side is midway between the
+poles and the axes of coil and pole coincide, the coil stands exactly
+opposite to the pole and embraces the same magnetic circuit as the
+field-magnet coils; its turns are therefore directly magnetizing,
+either weakening or strengthening the main flux according to the
+direction of the current. In intermediate positions the ampere-turns
+of the coil gradually pass from cross to direct and vice versa.
+When the instantaneous values of either the cross or direct magnetizing
+effect are integrated over a period and averaged, due
+account being taken of the number of slots per coil-side and of the
+different phases of the currents in the polyphase machine, expressions
+are obtained for the equivalent cross and direct ampere-turns of the
+armature as acting upon a pair of poles. For a given winding and
+current, the determining factor in either the one or the other is
+found to be the relative phase angle between the axis of a coil in
+its position when carrying the maximum current and the centre
+of a pole, the transverse reaction being proportional to the cosine
+of this angle, and the direct reaction to its sine. If the external
+circuit is inductive, the maximum value of the current lags behind
+the E.M.F. and so behind the centre of the pole; such a negative
+angle of lag causes the direct magnetizing turns to become back
+turns, directly weakening the main field and lowering the terminal
+voltage. Thus, just as in the continuous-current dynamo, for a
+given voltage under load the excitation between the pole-pieces
+X<span class="su">p</span> must not only supply the net excitation required over the air-gaps,
+armature core and teeth, but must also balance the back
+ampere-turns X<span class="su">b</span> of the armature.</p>
+
+<p>Evidently therefore the characteristic curve connecting armature
+current and terminal volts will with a constant exciting current
+depend on the nature of the load, whether inductive or non-inductive,
+and upon the amount of inductance already possessed by the armature
+itself. With an inductive load it will fall more rapidly from its
+initial maximum value, or, conversely, if the initial voltage is to be
+maintained under an increasing load, the exciting current will have
+to be increased more than if the load were non-inductive. In
+practical working many disadvantages result from a rapid drop of
+the terminal E.M.F. under increasing load, so that between no load
+and full load the variation in terminal voltage with constant excitation
+should not exceed 15%. Thus the output of an alternator
+is limited either by its heating or by its armature reaction, just as
+is the output of a continuous-current dynamo; in the case of the
+alternator, however, the limit set by armature reaction is not due
+to any sparking at the brushes, but to the drop in terminal voltage
+as the current is increased, and the consequent difficulty in maintaining
+a constant potential on the external circuit.</p>
+
+<p>The joint operation of several alternators so that their outputs
+may be delivered into the same external circuit is sharply distinguished
+from the corresponding problem in continuous-current
+dynamos by the necessary condition that they
+<span class="sidenote">The coupling of alternators.</span>
+must be in synchronism, <i>i.e.</i> not only must they be so
+driven that their frequency is the same, but their E.M.F.&rsquo;s
+must be in phase or, as it is also expressed, the machines
+must be in step. Although in practice it is impossible to run two
+alternators in series unless they are rigidly coupled together&mdash;which
+virtually reduces them to one machine&mdash;two or more machines can
+be run in parallel, as was first described by H. Wilde in 1868 and
+subsequently redemonstrated by J. Hopkinson and W.G. Adams
+in 1884. Their E.M.F.&rsquo;s should be as nearly as possible in synchronism,
+but, as contrasted with series connexion, parallel coupling
+gives them a certain power of recovery if they fall out of step, or
+are not in exact synchronism when thrown into parallel. In such
+circumstances a synchronizing current passes between the two
+machines, due to the difference in their instantaneous pressures;
+and as this current agrees in phase more nearly with the leading
+than with the lagging machine, the former machine does work as a
+generator on the latter as a motor. Hence the lagging machine
+is accelerated and the leading machine is retarded, until their
+frequencies and phase are again the same.</p>
+</div>
+
+<p>The chief use of the alternator has already been alluded to.
+Since it can be employed to produce very high pressures either
+directly or through the medium of transformers, it is
+specially adapted to the electrical transmission of
+<span class="sidenote">Uses of alternators.</span>
+energy over long distances.<a name="fa22p" id="fa22p" href="#ft22p"><span class="sp">22</span></a> In the early days of
+electric lighting, the alternate-current system was
+adopted for a great number of central stations; the machines,
+designed to give a pressure of 2000 volts, supplied transformers
+which were situated at considerable distances and spread over
+large areas, without an undue amount of copper in the transmitting
+lines. While there was later a tendency to return to
+the continuous current for central stations, owing to the introduction
+of better means for economizing the weight of copper in
+the mains, the alternating current again came into favour,
+as rendering it possible to place the central station in some
+convenient site far away from the district which it was to serve.
+The pioneer central station in this direction was the Deptford
+station of the London Electric Supply Corporation, which furnished
+current to the heart of London from a distance of 7 m.
+In this case, however, the alternators were single-phase and gave
+the high pressure of 10,000 volts immediately, while more
+recently the tendency has been to employ step-up transformers
+and a polyphase system. The advantage of the latter is that
+the current, after reaching the distant sub-stations, can be dealt
+with by rotary converters, through which it is transformed
+into a continuous current. The alternator is also used for
+welding, smelting in electric furnaces, and other metallurgical
+processes where heating effects are alone required; the large
+currents needed therein can be produced without the disadvantage
+of the commutator, and, if necessary, transformers can be
+interposed to lower the voltage and still further increase the
+current. The alternating system can thus meet very various
+needs, and its great recommendation may be said to lie in the
+flexibility with which it can supply electrical energy through
+transformers at any potential, or through rotary converters in
+continuous-current form.</p>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;For the further study of the dynamo, the following
+may be consulted, in addition to the references already given:&mdash;</p>
+
+<p><i>General</i>: S.P. Thompson, <i>Dynamo-Electric Machinery&mdash;Continuous-Current
+Machines</i> (1904), <i>Alternating-Current Machinery</i>
+(1905, London); G. Kapp, <i>Dynamos, Alternators and Transformers</i>
+(London, 1893); <i>Id., Electric Transmission of Energy</i> (London,
+1894); Id., <i>Dynamo Construction; Electrical and Mechanical</i>
+(London, 1899); H.F. Parshall and H.M. Hobart, <i>Electric Generators</i>
+(London, 1900); C.C. Hawkins and F. Wallis, <i>The Dynamo</i> (London,
+1903); E. Arnold, <i>Konstruktionstafeln für den Dynamobau</i> (Stuttgart,
+1902); C.P. Steinmetz, <i>Elements of Electrical Engineering</i>
+(New York, 1901).</p>
+
+<p><i>Continuous-Current Dynamos</i>: J. Fischer-Hinnen, <i>Continuous-Current
+Dynamos</i> (London, 1899); E. Arnold, <i>Die Gleichstrommaschine</i>
+(Berlin, 1902); F. Niethammer, <i>Berechnung und Konstruktion
+der Gleichstrommaschinen und Gleichstrommotoren</i> (Stuttgart,
+1904).</p>
+
+<p><i>Alternators</i>: D.C. Jackson and J.P. Jackson, <i>Alternating
+Currents and Alternating Current Machinery</i> (New York, 1903);
+J.A. Fleming, <i>The Alternate Current Transformer</i> (London, 1899);
+C.P. Steinmetz, <i>Alternating Current Phenomena</i> (New York, 1900);
+E. Arnold, <i>Die Wechselstromtechnik</i> (Berlin, 1904); S.P. Thompson,
+<i>Polyphase Electric Currents</i> (London, 1900); A. Stewart, <i>Modern
+Polyphase Machinery</i> (London, 1906); M. Oudin, <i>Standard Polyphase
+Apparatus and Systems</i> (New York, 1904).</p>
+</div>
+<div class="author">(C. C. H.)</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1p" id="ft1p" href="#fa1p"><span class="fn">1</span></a> <i>Experimental Researches in Electricity</i>, series ii. § 6, pars. 256,
+259-260, and series xxviii. § 34.</p>
+
+<p><a name="ft2p" id="ft2p" href="#fa2p"><span class="fn">2</span></a> <i>Ibid.</i> series i. § 4, pars. 84-90.</p>
+
+<p><a name="ft3p" id="ft3p" href="#fa3p"><span class="fn">3</span></a> &ldquo;On the Physical Lines of Magnetic Force,&rdquo; <i>Phil. Mag.</i>, June
+1852.</p>
+
+<p><a name="ft4p" id="ft4p" href="#fa4p"><span class="fn">4</span></a> Faraday, <i>Exp. Res.</i> series xxviii. § 34, pars. 3104, 3114-3115.</p>
+
+<p><a name="ft5p" id="ft5p" href="#fa5p"><span class="fn">5</span></a> <i>Id.</i>, ib. series i. § 4, pars. 114-119.</p>
+
+<p><a name="ft6p" id="ft6p" href="#fa6p"><span class="fn">6</span></a> <i>Id.</i>, ib. series ii. § 6, pars. 211, 213; series xxviii. § 34, par.
+3152.</p>
+
+<p><a name="ft7p" id="ft7p" href="#fa7p"><span class="fn">7</span></a> Invented by Nikola Tesla (<i>Elec. Eng.</i> vol. xiii. p. 83. Cf. Brit.
+Pat. Spec. Nos. 2801 and 2812, 1894). Several early inventors, <i>e.g.</i>
+Salvatore dal Negro in 1832 (<i>Phil. Mag.</i> third series, vol. i. p. 45),
+adopted reciprocating or oscillatory motion, and this was again tried
+by Edison in 1878.</p>
+
+<p><a name="ft8p" id="ft8p" href="#fa8p"><span class="fn">8</span></a> The advantage to be obtained by making the poles closely
+embrace the armature core was first realized by Dr Werner von
+Siemens in his &ldquo;shuttle-wound&rdquo; armature (Brit. Pat. No. 2107,
+1856).</p>
+
+<p><a name="ft9p" id="ft9p" href="#fa9p"><span class="fn">9</span></a> <i>Nuovo Cimento</i> (1865), 19, 378.</p>
+
+<p><a name="ft10p" id="ft10p" href="#fa10p"><span class="fn">10</span></a> Brit. Pat. No. 1668 (1870); <i>Comptes rendus</i> (1871), 73, 175.</p>
+
+<p><a name="ft11p" id="ft11p" href="#fa11p"><span class="fn">11</span></a> <i>Ann. Chim. Phys.</i> l. 322.</p>
+
+<p><a name="ft12p" id="ft12p" href="#fa12p"><span class="fn">12</span></a> Ibid. li. 76. Since in H. Pixii&rsquo;s machine the armature was
+stationary, while both magnet and commutator rotated, four
+brushes were used, and the arrangement was not so simple as
+the split-ring described above, although the result was the same.
+J. Saxton&rsquo;s machine (1833) and E.M. Clarke&rsquo;s machine (1835, see
+Sturgeon&rsquo;s <i>Annals of Electricity</i>, i. 145) were similar to one another
+in that a unidirected current was obtained by utilizing every alternate
+half-wave of E.M.F., but the former still employed mercury
+collecting cups, while the latter employed metal brushes. W.
+Sturgeon in 1835 followed Pixii in utilizing the entire wave of
+E.M.F., and abandoned the mercury cups in favour of metal brushes
+pressing on four semicircular disks (<i>Scientific Researches</i>, p. 252).
+The simple split-ring is described by Sir C. Wheatstone and Sir W.F.
+Cooke in their Patent No. 8345 (1840).</p>
+
+<p><a name="ft13p" id="ft13p" href="#fa13p"><span class="fn">13</span></a> By the &ldquo;leading&rdquo; side of the tooth or of an armature coil or
+sector is to be understood that side which first enters under a pole
+after passing through the interpolar gap, and the edge of the pole
+under which it enters is here termed the &ldquo;leading&rdquo; edge as opposed
+to the &ldquo;trailing&rdquo; edge or corner from under which a tooth or coil
+emerges into the gap between the poles; cf. fig. 30, where the leading
+and trailing pole-corners are marked ll and tt.</p>
+
+<p><a name="ft14p" id="ft14p" href="#fa14p"><span class="fn">14</span></a>  Such was the arrangement of Wheatstone&rsquo;s machine (Brit. Pat.
+No. 9022) of 1841, which was the first to give a more nearly &ldquo;continuous&rdquo;
+current, the number of sections and split-rings being five.</p>
+
+<p><a name="ft15p" id="ft15p" href="#fa15p"><span class="fn">15</span></a> Its development from the split-ring was due to Pacinotti and
+Gramme (Brit. Pat. No. 1668, 1870) in connexion with their ring
+armatures.</p>
+
+<p><a name="ft16p" id="ft16p" href="#fa16p"><span class="fn">16</span></a> And extended by G. Kapp, &ldquo;On Modern Continuous-Current
+Dynamo-Electric Machines,&rdquo; <i>Proc. Inst. C.E.</i> vol. lxxxiii. p. 136.</p>
+
+<p><a name="ft17p" id="ft17p" href="#fa17p"><span class="fn">17</span></a> Drs J. and E. Hopkinson, &ldquo;Dynamo-Electric Machinery,&rdquo; Phil.
+Trans., May 6, 1886; this was further expanded in a second paper
+on &ldquo;Dynamo-Electric Machinery,&rdquo; <i>Proc. Roy. Soc.</i>, Feb. 15, 1892,
+and both are reprinted in <i>Original Papers on Dynamo-Machinery
+and Allied Subjects</i>.</p>
+
+<p><a name="ft18p" id="ft18p" href="#fa18p"><span class="fn">18</span></a> <i>Exp. Res.</i>, series i. § 4, par. 111. In 1845 Wheatstone and Cooke
+patented the use of &ldquo;voltaic&rdquo; magnets in place of permanent
+magnets (No. 10,655).</p>
+
+<p><a name="ft19p" id="ft19p" href="#fa19p"><span class="fn">19</span></a> Between Moutiers and Lyons, a distance of 115 m., energy is
+transmitted on the Thury direct-current system at a maximum
+pressure of 60,000 volts. Four groups of machines in series are
+employed, each group consisting of four machines in series; the
+rated output of each component machine is 75 amperes at 3900
+volts or 400 h.p. A water turbine drives two pairs of such machines
+through an insulating coupling, and the sub-base of each pair of
+machines is separately insulated from earth, the foundation being
+also of special insulating materials.</p>
+
+<p><a name="ft20p" id="ft20p" href="#fa20p"><span class="fn">20</span></a> For experiments on high-frequency currents, Nikola Tesla constructed
+an alternator having 384 poles and giving a frequency of
+about 10,000 (<i>Journ. Inst. Elec. Eng.</i> 1892, 21, p. 82). The opposite
+extreme is found in alternators directly coupled to the Parsons steam-turbine,
+in which, with a speed of 3000 revs. per min., only two
+poles are required to give a frequency of 50. By a combination
+of a Parsons steam-turbine running at 12,000 revs. per min. with an
+alternator of 140 poles a frequency of 14,000 has been obtained
+(<i>Engineering</i>, 25th of August 1899). For description of an experimental
+machine for 10,000 cycles per second when running at
+3000 revs. per min., see <i>Trans. Amer. Inst. Elect. Eng.</i> vol. xxiii.
+p. 417.</p>
+
+<p><a name="ft21p" id="ft21p" href="#fa21p"><span class="fn">21</span></a> As in the historical transmission of energy from Lauffen to
+Frankfort (1891).</p>
+
+<p><a name="ft22p" id="ft22p" href="#fa22p"><span class="fn">22</span></a> In the pioneer three-phase transmission between Laufen and
+Frankfort (<i>Electrician</i>, vol. xxvi. p. 637, and xxvii. p. 548), the
+three-phase current was transformed up from about 55 to 8500 volts,
+the distance being 110 m. A large number of installations driven
+by water power are now at work, in which energy is transmitted
+on the alternating-current system over distances of about 100 m.
+at pressures ranging from 20,000 to 67,000 volts.</p>
+</div>
+
+<p><span class="pagenum"><a name="page782" id="page782"></a>782</span></p>
+
+
+<hr class="art" />
+<p><span class="bold">DYNAMOMETER<a name="ar8" id="ar8"></a></span> (Gr. <span class="grk" title="dynamis">&#948;&#973;&#957;&#945;&#956;&#953;&#962;</span>, strength, and <span class="grk" title="metron">&#956;&#941;&#964;&#961;&#959;&#957;</span>, a
+measure), an instrument for measuring force exerted by men,
+animals and machines. The name has been applied generally to
+all kinds of instruments used in the measurement of a force, as for
+example electric dynamometers, but the term specially denotes
+apparatus used in connexion with the measurement of work, or
+in the measurement of the horse-power of engines and motors. If
+P represent the average value of the component of a force in the
+direction of the displacement, s, of its point of application, the
+product Ps measures the work done during the displacement.
+When the force acts on a body free to turn about a fixed axis
+only, it is convenient to express the work done by the transformed
+product T&theta;, where T is the average turning moment or
+torque acting to produce the displacement &theta; radians. The
+apparatus used to measure P or T is the dynamometer. The
+factors s or &theta; are observed independently. Apparatus is added
+to some dynamometers by means of which a curve showing the
+variations of P on a distance base is drawn automatically, the
+area of the diagram representing the work done; with others,
+integrating apparatus is combined, from which the work done
+during a given interval may be read off directly. It is convenient
+to distinguish between absorption and transmission dynamometers.
+In the first kind the work done is converted into
+heat; in the second it is transmitted, after measurement, for
+use.</p>
+
+<div class="condensed">
+<p><i>Absorption Dynamometers.</i>&mdash;Baron Prony&rsquo;s dynamometer (<i>Ann.
+Chim. Phys.</i> 1821, vol. 19), which has been modified in various
+ways, consists in its original form of two symmetrically shaped
+timber beams clamped to the engine-shaft. When these are held
+from turning, their frictional resistance may be adjusted by means
+of nuts on the screwed bolts which hold them together until the
+shaft revolves at a given speed. To promote smoothness of action,
+the rubbing surfaces are lubricated. A weight is moved along the
+arm of one of the beams until it just keeps the brake steady midway
+between the stops which must be provided to hold it when the weight
+fails to do so. The general theory of this kind of brake is as
+follows:-Let F be the whole frictional resistance, r the common
+radius of the rubbing surfaces, W the force which holds the brake
+from turning and whose line of action is at a perpendicular distance
+R from the axis of the shaft, N the revolutions of the shaft per
+minute, &omega; its angular velocity in radians per second; then, assuming
+that the adjustments are made so that the engine runs steadily at a
+uniform speed, and that the brake is held still, clear of the stops
+and without oscillation, by W, the torque T exerted by the engine
+is equal to the frictional torque Fr acting at the brake surfaces,
+and this is measured by the statical moment of the weight W about
+the axis of revolution; that is&mdash;</p>
+
+<p class="center">T = Fr = WR.</p>
+<div class="author">(1)</div>
+
+<p class="noind">Hence WR measures the torque T.</p>
+
+<p>If more than one force be applied to hold the brake from turning,
+Fr, and therefore T, are measured by the algebraical sum of their
+individual moments with respect to the axis. If the brake is not
+balanced, its moment about the axis must be included. Therefore,
+quite generally,</p>
+
+<p class="center">T = &Sigma;WR.</p>
+<div class="author">(2)</div>
+
+<p class="noind">The factor &theta; of the product T&theta; is found by means of a revolution
+counter. The power of a motor is measured by the rate at which it
+works, and this is expressed by T&omega; = T2&pi;N / 60 in foot-pounds per second,
+or T2&pi;N / 33,000 in horse-power units. The latter is commonly referred to
+as the &ldquo;brake horse-power.&rdquo; The maintenance of the conditions of
+steadiness implied in equation (1) depends upon the constancy of
+F, and therefore of the coefficient of friction &mu; between the rubbing
+surfaces. The heating at the surfaces, the variations in their smoothness,
+and the variations of the lubrication make &mu; continuously
+variable, and necessitate frequent adjustment of W or of the nuts.
+J.V. Poncelet (1788-1867) invented a form of Prony brake which
+automatically adjusted its grip as &mu; changed, thereby maintaining
+F constant.</p>
+
+<p>The principle of the compensating brake devised by J.G. Appold
+(1800-1865) is shown in fig. 1. A flexible steel band, lined with
+wood blocks, is gripped on the motor fly-wheel or pulley by a screw
+A, which, together with W, is adjusted to hold the brake steady.
+Compensation is effected by the lever L inserted at B. This has a
+slotted end, engaged by a pin P fixed to the framing, and it will be
+seen that its action is to slacken the band if the load tends to rise
+and to tighten it in the contrary case. The external forces holding
+the brake from turning are W, distant R from the axis, and the reaction,
+W<span class="su">1</span> say, of the lever against the fixed pin P, distant R<span class="su">1</span>
+from the axis. The moment of W<span class="su">1</span> may be positive or negative.
+The torque T at any instant of steady running is therefore
+{WR ± W<span class="su">1</span>R<span class="su">1</span>}.</p>
+
+<table class="flt" style="float: right; width: 330px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:283px; height:302px" src="images/img782a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 1.</span></td></tr>
+<tr><td class="figright1"><img style="width:297px; height:702px" src="images/img782b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 2.</span></td></tr></table>
+
+<p>Lord Kelvin patented a brake in 1858 (fig. 2) consisting of a
+rope or cord wrapped round the circumference of a rotating
+wheel, to one end of which is applied a regulated force, the other
+end being fixed to a spring
+balance. The ropes are
+spaced laterally by the blocks
+B, B, B, B, which also serve
+to prevent them from slipping
+sideways. When the
+wheel is turning in the direction
+indicated, the forces
+holding the band still are
+W, and p, the observed pull
+on the spring balance. Both
+these forces usually act at
+the same radius R, the distance
+from the axis to the
+centre line of the rope, in
+which case the torque T is
+(W &minus; p)R, and consequently
+the brake horse-power is
+[(W &minus; p)R × 2&pi;N] / 33,000.
+When &mu; changes the weight W rises or
+falls against the action of the spring balance until a stable condition
+of running is obtained. The ratio W/p is given by e<span class="sp">&mu;&theta;</span>, where e = 2.718;
+&mu; is the coefficient of friction and &theta; the angle, measured in radians,
+subtended by the arc of contact between the rope and the wheel. In
+fig. 2 &theta; = 2&pi;. The ratio W/p increases very rapidly as &theta; is increased,
+and therefore, by making &theta; sufficiently large, p may conveniently
+be made a small fraction of W, thereby rendering errors of observation
+of the spring balance negligible. Thus this kind of brake,
+though cheap to make, is, when &theta; is large enough, an exceedingly
+accurate measuring instrument, readily applied and easily controlled.
+It has come into very general use in recent years, and has practically
+superseded the older forms
+of block brakes.</p>
+
+<p>It is sometimes necessary
+to use water to keep the
+brake wheel cool. Engines
+specially designed for testing
+are usually provided
+with a brake wheel having
+a trough-shaped rim. Water
+trickles continuously into
+the trough, and the centrifugal
+action holds it as an
+inside lining against the rim,
+where it slowly evaporates.</p>
+
+<p>Fig. 3 shows a band-brake
+invented by Professor James
+Thomson, suitable for testing
+motors exerting a constant
+torque (see <i>Engineering</i>,
+22nd October 1880).
+To maintain e<span class="sp">&mu;&theta;</span> constant,
+compensation for variation
+of &mu; is made by inversely
+varying &theta;. A and B are fast
+and loose pulleys, and the
+brake band is placed partly
+over the one and partly over
+the other. Weights W and
+w are adjusted to the torque.
+The band turns with the fast
+pulley if &mu; increase, thereby
+slightly turning the loose
+pulley, otherwise at rest,
+until &theta; is adjusted to the
+new value of &mu;. This form
+of brake was also invented
+independently by J.A.M.L.
+Carpentier, and the principle
+has been used in the
+Raffard brake. A self-compensating
+brake of another
+kind, by Marcel Deprez,
+was described with Carpentier&rsquo;s
+in 1880 (<i>Bulletin
+de la société d&rsquo;encouragement</i>,
+Paris). W.E. Ayrton
+and J. Perry used a band or rope brake in which compensation is
+effected by the pulley drawing in or letting out a part of the band
+or rope which has been roughened or in which a knot has been tied.</p>
+
+<table class="flt" style="float: left; width: 280px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:256px; height:309px" src="images/img783a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 3.</td></tr></table>
+
+<p>In an effective water-brake invented by W. Froude (see <i>Proc.
+Inst. M. E.</i> 1877), two similar castings, A and B, each consisting
+<span class="pagenum"><a name="page783" id="page783"></a>783</span>
+of a boss and circumferential annular channel, are placed face to face
+on a shaft, to which B is keyed, A being free (fig. 4). A ring tube of
+elliptical section is thus formed. Each channel is divided into a
+series of pockets by equally spaced vanes inclined at 45°. When
+A is held still, and B rotated, centrifugal action sets up vortex
+currents in the water in the pockets; thus a continuous circulation
+is caused between B and A, and the consequent changes of momentum
+give rise to oblique reactions. The moments of the components
+of these actions and reactions in a plane to which the axis of rotation
+is at right angles are the two
+aspects of the torque acting, and
+therefore the torque acting on B
+through the shaft is measured by
+the torque required to hold A
+still. Froude constructed a brake
+to take up 2000 H.P. at 90
+revs. per min. by duplicating this
+apparatus. This replaced the
+propeller of the ship whose
+engines were to be tested, and
+the outer casing was held from
+turning by a suitable arrangement
+of levers carried to weighing
+apparatus conveniently disposed
+on the wharf. The torque corresponding
+to 2000 H.P. at 90 revs.
+per min. is 116,772 foot-pounds,
+and a brake 5 ft. in diameter
+gave this resistance. Thin metal
+sluices were arranged to slide between
+the wheel and casing, and
+by their means the range of action could be varied from 300 H.P.
+at 120 revs. per min. to the maximum.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:479px; height:437px" src="images/img783b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 4.</td></tr></table>
+
+<p>Professor Osborne Reynolds in 1887 patented a water-brake (see
+<i>Proc. Inst. C.E.</i> 99, p. 167), using Froude&rsquo;s turbine to obtain the
+highly resisting spiral vortices, and arranging passages in the casing
+for the entry of water at the hub of the wheel and its exit at the
+circumference. Water enters at E (fig. 5), and finds its way into the
+interior of the wheel, A, driving the air in front of it through the air-passages
+K, K. Then following into the pocketed chambers V<span class="su">1</span>, V<span class="su">2</span>,
+it is caught into the vortex, and finally escapes at the circumference,
+flowing away at F. The air-ways k, k, in the fixed vanes establish
+communication between the cores of the vortices and the atmosphere.
+From <span class="spp">1</span>&frasl;<span class="suu">5</span> to 30 H.P. may be measured at 100 revs. per min.
+by a brake-wheel of this kind 18 in. in diameter. For other speeds
+the power varies as the cube of the speed. The casing is held from
+turning by weights hanging on an attached arm. The cocks regulating
+the water are connected to the casing, so that any tilting
+automatically regulates the flow, and therefore the thickness of the
+film in the vortex. In this way the brake may be arranged to
+maintain a constant torque, not withstanding variation of the speed.
+In G.I. Alden&rsquo;s brake (see <i>Trans. Amer. Soc. Eng.</i> vol. xi.) the
+resistance is obtained by turning a cast iron disk against the frictional
+resistance of two thin copper plates, which are held in a casing
+free to turn upon the shaft, and are so arranged that the pressure
+between the rubbing surfaces is controlled, and the heat developed
+by friction carried away, by the regulated flow of water through the
+casing. The torque required to hold the casing still against the action
+of the disk measures the torque exerted by the shaft to which the
+disk is keyed.</p>
+
+<table class="flt" style="float: right; width: 320px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:297px; height:453px" src="images/img783c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 5.</td></tr>
+<tr><td class="figright1"><img style="width:233px; height:239px" src="images/img783d.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 6.</td></tr></table>
+
+<p><i>Transmission Dynamometers.</i>&mdash;The essential part of many transmission
+dynamometers is a spring whose deformation indirectly
+measures the magnitude of the force transmitted through it. For
+many kinds of spring the change of form is practically proportional
+to the force, but the relation should always be determined experimentally.
+General A.J. Morin (see <i>Notice sur divers appareils
+dynamométriques</i>, Paris, 1841), in his classical experiments on
+traction, arranged his apparatus
+so that the change in
+form of the spring was continuously
+recorded on a sheet
+of paper drawn under a style.
+For longer experiments he
+used a &ldquo;Compteur&rdquo; or
+mechanical integrator, suggested
+by J.V. Poncelet,
+from which the work done
+during a given displacement
+could be read off directly.
+This device consists of a
+roller of radius r, pressed
+into contact with a disk.
+The two are carried on a
+common frame, so arranged
+that a change in form of
+the spring causes a relative
+displacement of the disk and
+roller, the point of contact
+moving radially from or
+towards the centre of the
+disk. The radial distance x is
+at any instant proportional
+to the force acting through
+the spring. The angular displacement,
+&theta;, of the disk is
+made proportional to the
+displacement, s, of the point
+of application of the force
+by suitable driving gear. If d&phi; is the angular displacement of
+the roller corresponding to displacements, d&theta; of the disk, and
+ds of the point of application of P, a, and C constants, then
+d&phi; = xd&theta; / r = (a/r) P ds = C·P ds, and therefore
+&phi; = C <span class="f150">&int;</span><span class="sp1">S2</span><span class="su1">S1</span> P ds;
+ that is, the angular displacement of the roller measures the work done
+during the displacement from s<span class="su">1</span> to s<span class="su">2</span>. The shaft carrying the
+roller is connected to a counter so that &phi; may be observed. The
+angular velocity of the shaft is proportional to the rate of working.
+Morin&rsquo;s dynamometer is shown in fig. 6. The transmitting spring is
+made up of two flat bars linked at their ends. Their centres s<span class="su">1</span>, s<span class="su">2</span>,
+are held respectively by the pieces A, B, which together form a sliding
+pair. The block A carries the disk D, B carries the roller R and
+counting gear. The pulley E is driven from an axle of the carriage.
+In a dynamometer used by F.W. Webb to measure the tractive
+resistance of trains on the London &amp; North-Western railway, a
+tractive pull or push compresses two spiral springs by a definite
+amount, which is recorded to scale by a pencil on a sheet of paper,
+drawn continuously from a storage drum at the rate of 3 in. per
+mile, by a roller driven from one of the carriage axles. Thus the
+diagram shows the tractive force at any instant. A second pencil
+electrically connected to a clock traces a time line on the diagram
+with a kick at every thirty seconds. A third pencil traces an observation
+line in which a kick can be made at will by pressing any one
+of the electrical pushes placed about the car, and a fourth draws
+a datum line. The spring of the
+dynamometer car used by W. Dean
+on the Great Western railway is made
+up of thirty flat plates, 7 ft. 6 in.
+long, 5 in. × <span class="spp">5</span>&frasl;<span class="suu">8</span> in. at the centre, spaced
+by distance pieces nibbed into the
+plates at the centre and by rollers at
+the ends. The draw-bar is connected
+to the buckle, which is carried on
+rollers, the ends of the spring resting
+on plates fixed to the under-frame.
+The gear operating the paper roll is
+driven from the axle of an independent
+wheel which is let down into
+contact with the rail when required.
+This wheel serves also to measure
+the distance travelled. A Morin disk
+and roller integrator is connected
+with the apparatus, so that the work done during a journey may
+be read off. Five lines are traced on the diagram.</p>
+
+<table class="flt" style="float: left; width: 350px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:309px; height:366px" src="images/img784a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 7.</td></tr></table>
+
+<p>In spring dynamometers designed to measure a transmitted
+torque, the mechanical problem of ascertaining the change of
+form of the spring is complicated by the fact that the spring and
+the whole apparatus are rotating together. In the Ayrton and
+Perry transmission dynamometer or spring coupling of this type,
+<span class="pagenum"><a name="page784" id="page784"></a>784</span>
+the relative angular displacement is proportional to the radius
+of the circle described by the end of a light lever operated by
+mechanism between the spring-connected parts. By a device used
+by W.E. Dalby (<i>Proc. Inst.C.E.</i> 1897-1898, p. 132) the change in
+form of the spring is shown on a fixed indicator, which may be placed
+in any convenient position. Two equal sprocket wheels Q<span class="su">1</span>, Q<span class="su">2</span>, are
+fastened, the one to the spring pulley, the other to the shaft. An
+endless band is placed over them to form two loops, which during
+rotation remain at the same distance apart, unless relative angular
+displacement occurs between
+Q<span class="su">1</span> and Q<span class="su">2</span> (fig. 7)
+due to a change in form
+of the spring. The change
+in the distance <i>d</i> is proportional
+to the change
+in the torque transmitted
+from the shaft to the
+pulley. To measure this,
+guide pulleys are placed
+in the loops guided by a
+geometric slide, the one
+pulley carrying a scale,
+and the other an index.
+A recording drum or integrating
+apparatus may
+be arranged on the pulley
+frames. A quick variation,
+or a periodic variation of
+the magnitude of the force
+or torque transmitted
+through the springs, tends
+to set up oscillations, and
+this tendency increases
+the nearer the periodic
+time of the force variation
+approaches a periodic time of the spring. Such vibrations may be
+damped out to a considerable extent by the use of a dash-pot,
+or may be practically prevented by using a relatively stiff spring.</p>
+
+<p>Every part of a machine transmitting force suffers elastic deformation,
+and the force may be measured indirectly by measuring
+the deformation. The relation between the two should in all cases
+be found experimentally. G.A. Hirn (see <i>Les Pandynamomètres</i>,
+Paris, 1876) employed this principle to measure the torque transmitted
+by a shaft. Signor Rosio used a telephonic method to effect
+the same end, and mechanical, optical and telephonic devices have
+been utilized by the Rev. F.J. Jervis-Smith. (See <i>Phil. Mag.</i>
+February 1898.)</p>
+
+<p>H. Frahm,<a name="fa1q" id="fa1q" href="#ft1q"><span class="sp">1</span></a> during an important investigation on the torsional
+vibration of propeller shafts, measured the relative angular displacement
+of two flanges on a propeller shaft, selected as far apart as
+possible, by means of an electrical device (<i>Engineering</i>, 6th of
+February 1903). These measurements were utilized in combination
+with appropriate elastic coefficients of the material to find the
+horse-power transmitted from the engines along the shaft to the
+propeller. In this way the effective horse-power and also the
+mechanical efficiency of a number of large marine engines, each of
+several thousand horse-power, have been determined.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:438px; height:216px" src="images/img784b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 8.</td></tr></table>
+
+<p>When a belt, in which the maximum and minimum tensions
+are respectively P and p &#8468;, drives a pulley, the torque exerted
+is (P &minus; p)r &#8468; ft., r being the radius of the pulley plus half the thickness
+of the belt. P and p may be measured directly by leading the
+belt round two freely hanging guide pulleys, one in the tight, the
+other in the slack part of the belt, and adjusting loads on them until
+a stable condition of running is obtained. In W. Froude&rsquo;s belt
+dynamometer (see <i>Proc. Inst. M.E.</i>, 1858) (fig. 8) the guide pulleys
+G<span class="su">1</span>, G<span class="su">2</span> are carried upon an arm free to turn about the axis O. H
+is a pulley to guide the approaching and receding parts of the belt
+to and from the beam in parallel directions. Neglecting friction, the
+unbalanced torque acting on the beam is 4r {P &minus; p} &#8468; ft. If a force
+Q acting at R maintains equilibrium, QR/4 = (P &minus; p)r = T. Q is
+supplied by a spring, the extensions of which are recorded on a drum
+driven proportionally to the angular displacement of the driving
+pulley; thus a work diagram is obtained. In the Farcot form the
+guide pulleys are attached to separate weighing levers placed horizontally
+below the apparatus. In a belt dynamometer built for the
+Franklin Institute from the designs of Tatham, the weighing levers
+are separate and arranged horizontally at the top of the apparatus.
+The weighing beam in the Hefner-Alteneck dynamometer is placed
+transversely to the belt (see <i>Electrotechnischen Zeitschrift</i>, 1881, 7).
+The force Q, usually measured by a spring, required to maintain
+the beam in its central position is proportional to (P &minus; p). If
+the angle &theta;<span class="su">1</span> = &theta;<span class="su">2</span> = 120°, Q = (P &minus; p) neglecting friction.</p>
+
+<p>When a shaft is driven by means of gearing the driving torque
+is measured by the product of the resultant pressure P acting
+between the wheel teeth and the radius of the pitch circle of the
+wheel fixed to the shaft. Fig. 9, which has been reproduced from
+J. White&rsquo;s <i>A New Century of Inventions</i> (Manchester, 1822), illustrates
+possibly the earliest application of this principle to dynamometry.
+The wheel D, keyed to the shaft overcoming the resistance
+to be measured, is driven from wheel N by two bevel wheels L, L,
+carried in a loose pulley K. The two shafts, though in a line, are
+independent. A torque applied to the shaft A can be transmitted
+to D, neglecting friction, without change only if the central pulley
+K is held from turning; the torque required to do this is twice the
+torque transmitted.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:437px; height:434px" src="images/img784c.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 9.</td></tr></table>
+
+<p>The torque acting on the armature of an electric motor is necessarily
+accompanied by an equal and opposite torque acting on the
+frame. If, therefore, the motor is mounted on a cradle free to turn
+about knife-edges, the reacting torque is the only torque tending
+to turn the cradle when it is in a vertical position, and may therefore
+be measured by adjusting weights to hold the cradle in a vertical
+position. The rate at which the motor is transmitting work is then
+T2&pi;n / 550 H.P., where n is the revolutions per second of the armature.</p>
+
+<p>See James Dredge, <i>Electric Illumination</i>, vol. ii. (London, 1885);
+W.W. Beaumont, &ldquo;Dynamometers and Friction Brakes,&rdquo; <i>Proc.
+Inst.C.E.</i> vol. xcv. (London, 1889); E. Brauer, &ldquo;Über Bremsdynamometer
+and verwandte Kraftmesser,&rdquo; <i>Zeitschrift des Vereins
+deutscher Ingenieure</i> (Berlin, 1888); J.J. Flather, <i>Dynamometers
+and the Measurement of Power</i> (New York, 1893).</p>
+</div>
+<div class="author">(W. E. D.)</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1q" id="ft1q" href="#fa1q"><span class="fn">1</span></a> H. Frahm, &ldquo;Neue Untersuchungen über die dynamischen
+Vorgänge in den Wellenleitungen von Schiffsmaschinen mit besonderer
+Berücksichtigung der Resonanzschwingungen,&rdquo; <i>Zeitschrift
+des Vereins deutscher Ingenieure</i>, 31st May 1902.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">DYNASTY<a name="ar9" id="ar9"></a></span> (Gr. <span class="grk" title="dynasteia">&#948;&#965;&#957;&#945;&#963;&#964;&#949;&#943;&#945;</span>, sovereignty, the position of a
+<span class="grk" title="dynastês">&#948;&#965;&#957;&#940;&#959;&#964;&#951;&#962;</span>, lord, ruler, from <span class="grk" title="dynasthai">&#948;&#973;&#957;&#945;&#963;&#952;&#945;&#953;</span>, to be able, <span class="grk" title="dynamis">&#948;&#973;&#957;&#945;&#956;&#953;&#962;</span>, power),
+a family or line of rulers, a succession of sovereigns of a country
+belonging to a single family or tracing their descent to a common
+ancestor. The term is particularly used in the history of ancient
+Egypt as a convenient means of arranging the chronology.</p>
+
+
+<hr class="art" />
+<p><span class="bold">DYSART,<a name="ar10" id="ar10"></a></span> a royal and police burgh and seaport of Fifeshire,
+Scotland, on the shore of the Firth of Forth, 2 m. N.E. of Kirkcaldy
+by the North British railway. Pop. (1901) 3562. It has
+a quaint old-fashioned appearance, many ancient houses in
+High Street bearing inscriptions and dates. The public buildings
+include a town hall, library, cottage hospital, mechanics&rsquo;
+institute and memorial hall. Scarcely anything is left of the old
+chapel dedicated to St Dennis, which for a time was used as a
+<span class="pagenum"><a name="page785" id="page785"></a>785</span>
+smithy; and of the chapel of St Serf, the patron saint of the
+burgh, only the tower remains. The chief industries are the
+manufacture of bed and table linen, towelling and woollen cloth,
+shipbuilding and flax-spinning. There is a steady export of
+coal, and the harbour is provided with a wet dock and patent
+slip. In smuggling days the &ldquo;canty carles&rdquo; of Dysart were
+professed &ldquo;free traders.&rdquo; In the 15th and 16th centuries the
+town was a leading seat of the salt industry (&ldquo;salt to Dysart&rdquo;
+was the equivalent of &ldquo;coals to Newcastle&rdquo;), but the salt-pans
+have been abandoned for a considerable period. Nail-making,
+once famous, is another extinct industry. During the time
+of the alliance between Scotland and Holland, which was closer
+in Fifeshire than in other counties, Dysart became known as
+Little Holland. To the west of the town is Dysart House, the
+residence of the earl of Rosslyn. With Burntisland and Kinghorn
+Dysart forms one of the Kirkcaldy district group of parliamentary
+burghs. The town is mentioned as early as 874 in
+connexion with a Danish invasion. Its name is said to be a
+corruption of the Latin <i>desertum</i>, &ldquo;a desert,&rdquo; which was applied
+to a cave on the seashore occupied by St Serf. In the cave the
+saint held his famous colloquy with the devil, in which Satan
+was worsted and contemptuously dismissed. From James V.
+the town received the rights of a royal burgh. In 1559 it was the
+headquarters of the Lords of the Congregation, and in 1607 the
+scene of the meetings of the synod of Fife known as the Three
+Synods of Dysart. Ravensheugh Castle, on the shore to the west
+of the town, is the Ravenscraig of Sir Walter Scott&rsquo;s ballad of
+&ldquo;Rosabelle.&rdquo;</p>
+
+<p>William Murray, a native of the place, was made earl of Dysart
+in 1643, and his eldest child and heir, a daughter, Elizabeth,
+obtained in 1670 a regrant of the title, which passed to the descendants
+of her first marriage with Sir Lionel Tollemache, Bart.,
+of Helmingham; she married secondly the 1st duke of Lauderdale,
+but had no children by him, and died in 1698. This countess
+of Dysart (afterwards duchess of Lauderdale) was a famous
+beauty of the period, and notorious both for her amours and for
+her political influence. She was said to have been the mistress
+of Oliver Cromwell, and also of Lauderdale before her first
+husband&rsquo;s death, and was a leader at the court of Charles II.
+Wycherley is supposed to have aimed at her in his Widow
+Blackacre in the <i>Plain Dealer</i>. Her son, Lionel Tollemache
+(d. 1727), transmitted the earldom to his grandson Lionel (d.
+1770), whose sons Lionel (d. 1799) and Wilbraham (d. 1821)
+succeeded; they died without issue, and their sister Louisa (d.
+1840), who married John Manners, an illegitimate son of the
+second son of the 2nd duke of Rutland, became countess in her
+own right, being succeeded by her grandson (d. 1878), and his
+grandson, the 8th earl.</p>
+
+<p>The earldom of Dysart must not be confounded with that of
+Desart (Irish), created (barony 1733) in 1793, and held in the
+Cuffe family, who were originally of Creech St Michael, Somerset,
+the Irish branch dating from Queen Elizabeth&rsquo;s time.</p>
+
+
+<hr class="art" />
+<p><span class="bold">DYSENTERY<a name="ar11" id="ar11"></a></span> (from the Gr. prefix <span class="grk" title="dys">&#948;&#965;&#963;</span>-, in the sense of &ldquo;bad,&rdquo;
+and <span class="grk" title="enteron">&#7956;&#957;&#964;&#949;&#961;&#959;&#957;</span>, the intestine), also called &ldquo;bloody flux,&rdquo; an infectious
+disease with a local lesion in the form of inflammation
+and ulceration of the lower portion of the bowels. Although
+at one time a common disease in Great Britain, dysentery is
+now very rarely met with there, and is for the most part confined
+to warm countries, where it is the cause of a large amount of
+mortality. (For the pathology see <span class="sc"><a href="#artlinks">Digestive Organs</a></span>.)</p>
+
+<p>Recently considerable advance has been made in our knowledge
+of dysentery, and it appears that there are two distinct
+types of the disease: (1) amoebic dysentery, which is due to the
+presence of the amoeba histolytica (of Schaudinn) in the intestine;
+(2) bacillary dysentery, which has as causative agent two
+separate bacteria, (<i>a</i>) that discovered by Shiga in Japan, (<i>b</i>)
+that discovered by Flexner in the Philippine Islands. With
+regard to the bacillary type, at first both organisms were considered
+to be identical, and the name <i>bacillus dysenteriae</i> was
+given to them; but later it was shown that these bacilli are
+different, both in regard to their cultural characteristics and
+also in that one (Shiga) gives out a soluble toxin, whilst the
+other has so far resisted all efforts to discover it. Further, the
+serum of a patient affected with one of the types has a marked
+agglutinative power on the variety with which he is infected
+and not on the other.</p>
+
+<p>Clinically, dysentery manifests itself with varying degrees of
+intensity, and it is often impossible without microscopical
+examination to determine between the amoebic and bacillary
+forms. In well-marked cases the following are the chief symptoms.
+The attack is commonly preceded by certain premonitory
+indications in the form of general illness, loss of appetite, and
+some amount of diarrhoea, which gradually increases in severity,
+and is accompanied with griping pains in the abdomen (tormina).
+The discharges from the bowels succeed each other with great
+frequency, and the painful feeling of pressure downwards
+(tenesmus) becomes so intense that the patient is constantly
+desiring to defecate. The matters passed from the bowels,
+which at first resemble those of ordinary diarrhoea, soon change
+their character, becoming scanty, mucous or slimy, and subsequently
+mixed with, or consisting wholly of, blood, along with
+shreds of exudation thrown off from the mucous membrane of
+the intestine. The evacuations possess a peculiarly offensive
+odour characteristic of the disease. Although the constitutional
+disturbance is at first comparatively slight, it increases with the
+advance of the disease, and febrile symptoms come on attended
+with urgent thirst and scanty and painful flow of urine. Along
+with this the nervous depression is very marked, and the state
+of prostration to which the patient is reduced can scarcely be
+exceeded. Should no improvement occur death may take place
+in from one to three weeks, either from repeated losses of blood,
+or from gradual exhaustion consequent on the continuance of
+the symptoms, in which case the discharges from the bowels
+become more offensive and are passed involuntarily.</p>
+
+<p>When, on the other hand, the disease is checked, the signs
+of improvement are shown in the cessation of the pain, in the
+evacuations being less frequent and more natural, and in relief
+from the state of extreme depression. Convalescence is, however,
+generally slow, and recovery may be imperfect&mdash;the
+disease continuing in a chronic form, which may exist for a
+variable length of time, giving rise to much suffering, and not
+unfrequently leading to an ultimately fatal result.</p>
+
+<p>The dysentery poison appears to exert its effects upon the
+glandular structures of the large intestine, particularly in its
+lower part. In the milder forms of the disease there is simply
+a congested or inflamed condition of the mucous membrane,
+with perhaps some inflammatory exudation on its surface, which
+is passed off by the discharges from the bowels. But in the more
+severe forms ulceration of the mucous membrane takes place.
+Commencing in and around the solitary glands of the large intestine
+in the form of exudations, these ulcers, small at first,
+enlarge and run into each other, till a large portion of the bowel
+may be implicated in the ulcerative process. Should the disease
+be arrested these ulcers may heal entirely, but occasionally they
+remain, causing more or less disorganization of the coats of the
+intestines, as is often found in chronic dysentery. Sometimes,
+though rarely, the ulcers perforate the intestines, causing rapidly
+fatal inflammation of the peritoneum, or they may erode a blood
+vessel and produce violent haemorrhage. Even where they
+undergo healing they may cause such a stricture of the calibre
+of the intestinal canal as to give rise to the symptoms of obstruction
+which ultimately prove fatal. One of the severest complications
+of the disease is abscess of the liver, usually said to be
+solitary, and known as tropical abscess of the liver, but probably
+is more frequently multiple than is usually thought.</p>
+
+<p><i>Treatment.</i>&mdash;Where the disease is endemic or is prevailing
+epidemically, it is of great importance to use all preventive
+measures, and for this purpose the avoidance of all causes likely
+to precipitate an attack is to be enjoined. Exposure to cold
+after heat, the use of unripe fruit, and intemperance in eating
+and drinking should be forbidden; and the utmost care taken
+as to the quality of the food and drinking water. In houses or
+hospitals where cases of the disease are under treatment, disinfectants
+should be freely employed, and the evacuations of the
+<span class="pagenum"><a name="page786" id="page786"></a>786</span>
+patients removed as speedily as possible, having previously
+been sterilized in much the same manner as is employed in
+typhoid fever. In the milder varieties of this complaint, such
+as those occurring sporadically, and where the symptoms are
+probably due to matters in the bowels setting up the dysenteric
+irritation, the employment of diaphoretic medicines is to
+be recommended, and the administration of such a laxative as
+castor oil, to which a small quantity of laudanum has been added,
+will often, by removing the source of the mischief, arrest the
+attack; but a method of treatment more to be recommended is
+the use of salines in large doses, such as one drachm of sodium
+sulphate from four to eight times a day. This treatment may
+with advantage be combined with the internal administration
+of ipecacuanha, which still retains its reputation in this disease.
+Latterly, free irrigation of the bowel with astringents, such as
+silver nitrate, tannalbin, &amp;c., has been attended with success in
+those cases which have been able to tolerate the injections.
+In many instances they cannot be used owing to the extreme
+degree of irritability of the bowel. The operation of appendicostomy,
+or bringing the appendix to the surface and using it as
+the site for the introduction of the irrigating fluid, has been
+attended with considerable success.</p>
+
+<p>In those cases due to Shiga&rsquo;s bacillus the ideal treatment has
+been put at our disposal by the preparation of a specific antitoxin;
+this has been given a trial in several grave epidemics
+of late, and may be said to be the most satisfactory treatment
+and offer the greatest hope of recovery. It is also of great use
+as a prophylactic.</p>
+
+<p>The preparations of morphia are of great value in the symptomatic
+treatment of the disease. They may be applied externally
+as fomentations, for the relief of tormina; by rectal injection
+for the relief of the tenesmus and irritability of the bowel;
+hypodermically in advanced cases, for the relief of the general
+distress. In amoebic dysentery, warm injections of quinine <i>per
+rectum</i> have proved very efficacious, are usually well tolerated,
+and are not attended with any ill effects. The diet should be
+restricted, consisting chiefly of soups and farinaceous foods;
+more especially is this of importance in the chronic form. For
+the thirst ice may be given by the mouth. Even in the chronic
+forms, confinement to bed and restriction of diet are the
+most important elements of the treatment. Removal from the
+hot climate and unhygienic surroundings must naturally be
+attended to.</p>
+
+<div class="condensed">
+<p><span class="sc">Bibliography.</span>&mdash;Allbutt and Rolleston, <i>System of Medicine</i>,
+vol. ii. part ii. (1907), &ldquo;Dysentery,&rdquo; Drs Andrew Davidson and
+Simon Flexner; Davidson, <i>Hygiene and Diseases of Warm Climates</i>
+(Edinburgh, 1903); Fearnside in <i>Ind. Med. Gaz.</i> (July 1905); Ford
+in <i>Journal of Tropical Medicine</i> (July 15, 1904); Korentchewsky
+in <i>Bulletin de l&rsquo;Institut Pasteur</i> (February 1905); Shiga: Osier and
+M&rsquo;Crae&rsquo;s <i>System of Medicine</i>, vol. ii. p. 781 (1907); Skschivan and
+Stefansky in <i>Berliner klinische Wochenschrift</i> (February 11, 1907);
+Vaillard and Dopter, on the treatment by antidysenteric serum,
+<i>Annales de l&rsquo;Institut Pasteur</i>, No. 5, p. 326 (1906); J.A. Pottinger,
+&ldquo;Appendicostomy in Chronic Dysentery,&rdquo; <i>Lancet</i> (December 28,
+1907); Robert Doerr, <i>Das Dysenterietoxin</i> (Gustav Fischer, Jena,
+1907); F.M. Sandwith, &ldquo;Hunterian Lecture on the Treatment of
+Dysentery,&rdquo; <i>Lancet</i> (December 7, 1907).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">DYSPEPSIA<a name="ar12" id="ar12"></a></span> (from the Gr. prefix <span class="grk" title="dys">&#948;&#965;&#963;</span>-, hard, ill, and <span class="grk" title="peptein">&#960;&#941;&#960;&#964;&#949;&#953;&#957;</span>,
+to digest), or indigestion, a term vaguely given to a group of
+pathological symptoms. There are comparatively few diseases
+of any moment where some of the phenomena of dyspepsia are
+not present as associated symptoms, and not infrequently these
+exist to such a degree as to mask the real disease, of which they
+are only complications. This is especially the case in many
+organic diseases of the alimentary canal, in which the symptoms
+of dyspepsia are often the most prominent. In its restricted
+meaning, however (and it is to this that the present article
+applies), the term is used to describe a functional derangement
+of the natural process of digestion, apart from any structural
+change in the organs concerned in the act.</p>
+
+<p>The causes of this trouble may be divided into (<i>a</i>) those which
+concern the food, and (<i>b</i>) those which concern the organism.
+Among the causes connected with the food are not only the
+indulgence in indigestible articles of diet, but the too common
+practice of eating too much of what may be otherwise quite
+wholesome and digestible; and irregular, too frequent or too
+infrequent meals. The quantity of food required by different
+individuals varies between wide limits, but also the quantity
+required by the same individual varies considerably according
+to circumstances, more food being needed in cold than in warm
+weather, and more in an active open-air occupation than in a
+sedentary one. The thorough mastication of the food is a very
+important precursor of digestion,<a name="fa1r" id="fa1r" href="#ft1r"><span class="sp">1</span></a> and this only too often fails,
+either owing to haste over meals or because of painful or deficient
+teeth. Again, the quality of the food is of importance, some
+kinds of flesh being harder and more difficult of mastication
+than others. This is especially the case with meat that has
+been smoked or salted, and with that cooked too soon after the
+death of the animal. Drinks are a common source of dyspepsia.
+Beer when new and its fermentation not completed is especially
+bad. Vinegar and acid wines, if taken in large quantities, tend
+to produce gastric catarrh, and tea is a very fruitful source of
+this trouble. Even too much water at meal-times may cause
+indigestion, since the food in the mouth is apt to be softened
+by the water instead of saliva, and also the gastric juice becomes
+unduly diluted, rendering the digestion in the stomach too slow
+and prolonged. Carious teeth and oral sepsis, from whatsoever
+cause, lead to the same trouble.</p>
+
+<p>Of the causes which concern the organism, nervous influences
+come first. Bad news may take away all power of digestion
+and even provoke vomiting, and any worry or mental trouble
+tends to bring on this condition. General weakness and atony
+of the body affects the stomach in like degree, and, if the muscles
+of the abdominal wall be much wasted, they become too weak to
+support the abdominal viscera in place. Hence results a general
+tendency for these organs to fall, giving rise to a condition of
+visceroptosis, of which an obstinate dyspepsia is a very marked
+feature. Adhesions of the intestines from old inflammatory
+troubles, floating kidney and bad circulation may each be a
+cause of painful digestion. Again, a dyspepsia that will not
+yield to treatment is often one of the symptoms of renal disease,
+or, in young people of fifteen to twenty years of age, it may
+be the earliest sign of a gouty diathesis, or even of a more serious
+condition still&mdash;incipient phthisis. Chronic dyspepsia, by
+weakening the organism, renders it more liable to fall a prey to the
+attacks of the tubercle bacillus, but, on the other hand, the
+tuberculous lesion in the lung is often accompanied by a most
+intractable form of dyspepsia. From this it is clear that any
+condition which lessens the general well-being of the organism
+as a whole, apart from its producing any permanent morbid
+condition in the stomach, may yet interfere with the normal
+digestive processes and so give rise to dyspepsia.</p>
+
+<p>The symptoms of dyspepsia, even when due to a like cause,
+are so numerous and diversified in different individuals that
+probably no description could exactly represent them as they
+occur in any given case. All that can be here attempted is to
+mention some of the more prominent morbid phenomena usually
+present in greater or less degree.</p>
+
+<p>Very briefly, a furred tongue, foul breath, disturbance of
+appetite, nausea and vomiting, oppression in the chest, pain,
+flatulence and distension, acidity, pyrosis and constipation or
+diarrhoea are a few of the commonest symptoms.</p>
+
+<p>When the attack is dependent on some error in diet, and the
+dyspepsia consequently more of an acute character, there is
+often pain followed with sickness and vomiting of the offensive
+matters, after which the patient soon regains his former healthy
+state. What are commonly known as &ldquo;bilious attacks&rdquo; are
+frequently of this character. In the more chronic cases of
+dyspepsia the symptoms are somewhat different. A sensation
+of discomfort comes on shortly after a meal, and is more of the
+nature of weight and distension in the stomach than of actual
+pain, although this too may be present. These feelings may come
+<span class="pagenum"><a name="page787" id="page787"></a>787</span>
+on after each meal, or only after certain meals, and they may
+arise irrespective of the kind of food taken, or only after certain
+articles of diet. As in most of such cases the food is long retained
+in the stomach, it is apt to undergo fermentive changes,
+one of the results of which is the accumulation of gases which
+cause flatulence and eructations of an acid or foul character.
+Occasionally quantities of hot, sour, tasteless or bitter fluid&mdash;pyrosis&mdash;or
+mouthfuls of half-digested food, regurgitate from
+the stomach. Temporary relief may be obtained when another
+meal is taken, but soon the uncomfortable sensations return
+as before. The appetite may be craving or deficient, or desirous
+of abnormal kinds of food. The tongue registers the gastric
+condition with great delicacy;&mdash;a pasty white fur on the tongue
+is considered a sign of weakness or atony of the digestive tract;
+a clean pointed tongue with large papillae, and rather red at the
+edges and tip, is a sign of gastric irritation; and a pale flabby
+tongue suggests the need of stimulating treatment. Constipation
+is more common in the chronic forms of dyspepsia, diarrhoea in
+the acute.</p>
+
+<p>Numerous disagreeable and painful sensations in other parts
+are experienced, and are indeed often more distressing than the
+merely gastric symptoms. Pains in the chest, shortness of
+breathing, palpitation, headache, giddiness, affections of vision,
+coldness of the extremities, and general languor are common
+accompaniments of dyspepsia; while the nervous phenomena
+are specially troublesome in the form of sleeplessness, irritability,
+despondency and hypochondriasis.</p>
+
+<p>As regards <i>treatment</i> only a few general observations can be
+made. The careful arrangement of the diet is a matter of first
+importance. Quantity must be regulated by the digestive
+capabilities of the individual, his age, and the demands made
+upon his strength by work. There is little doubt that the danger
+is in most instances on the side of excess, and the rule which
+enjoins the cessation from eating before the appetite is satisfied
+is a safe one for dyspeptics. Due time, too, must be given for
+the digestion of a meal, and from four to six hours are in general
+required for this purpose. Long fasts, however, are nearly as
+hurtful as too frequent meals. Of no less importance is the kind
+of food taken, and on this point those who suffer from indigestion
+must ever exercise the greatest care. It must be borne in mind
+that idiosyncrasy often plays an important part in digestion,
+some persons being unable to partake without injury of substances
+which are generally regarded as wholesome and digestible.
+In most cases it is found very helpful to separate the protein
+from the farinaceous food, and the more severe the dyspepsia
+the more thoroughly should this be done, only relaxing as the
+dyspepsia yields. No fluid should be drunk at meal-times, but
+from one to two tumblers of hot water should be drunk from an
+hour to an hour and a half before food. This washes any remnant
+of the last meal from the stomach, and also supplies material for
+the free secretion of saliva and gastric juice, thus promoting
+and accelerating digestion. The only exception to this is in the
+case of a dilated stomach, when it is wholly contra-indicated.
+With regard to mastication, Sir Andrew Clark&rsquo;s rule is a very
+good one, and is more easily followed than the ideal theory laid
+down by Horace Fletcher, according to whom any food is digestible
+if properly treated while still in the mouth. Clark&rsquo;s rule is
+that as the mouth normally contains thirty-two teeth, thirty-two
+bites should be given before the food is swallowed. This,
+of course, is a practical doctor&rsquo;s concession to human weakness.
+Mr Fletcher would train every one to &ldquo;chew&rdquo; till the contents
+of the mouth were swallowed by reflex action without deliberate
+act; and he applies this theory of mastication and salivation
+also to drinks (except water). Again, a lack of warmth being
+a source of dyspepsia, this should be attended to, the back of
+the neck, the front of the abdomen and the feet being the parts
+that require special attention. The feet should be raised on
+a stool, the ankles protected with warm stockings and a woollen
+&ldquo;cummerbund&rdquo; wound two or three times round the body.
+Experience has shown that in this complaint no particular kind
+of food or avoidance of food is absolutely to be relied on, but
+that in general the best diet is one of a mixed animal and vegetable
+kind, simply but well cooked. The partaking of many
+dishes, of highly-seasoned or salted meats, raw vegetables, newly-baked
+bread, pastry and confectionery are all well-known
+common causes of dyspepsia, and should be avoided. When
+even the simple diet usually taken is found to disagree, it
+may be necessary to change it temporarily for a still lighter
+form, such as a milk diet, and that even in very moderate
+quantity.</p>
+
+<p>The employment of alcoholic stimulants to assist digestion
+is largely resorted to, both with and without medical advice.
+While it seems probable that in certain cases of atonic dyspepsia,
+particularly in the feeble and aged, the moderate administration
+of alcohol has the effect of stimulating the secretion of gastric
+juice, and is an important adjuvant to other remedies, the
+advantages of its habitual use as an aid to digestion by the young
+and otherwise healthy, is more than questionable, and it will
+generally be found that among them, those are least troubled
+with indigestion who abstain from it. Rest should be taken
+both before and after food, and general hygienic measures are
+highly important, since whatever improves the state of the
+health will have a favourable influence on digestion. Hence
+regular exercise in the open air, early rising and the cold bath
+are to be strongly recommended.</p>
+
+<p>The medicinal treatment of dyspepsia can only be undertaken
+by a physician, but the following is a very brief résumé of the
+drugs he depends on to-day. Bicarbonate of soda with some
+bitter, as quassia, gentian or columba, is much in vogue as a
+direct gastric stimulant. In irritable dyspepsia some form of
+bismuth in solution or powder; and, to assist digestion through
+the nervous system, nux vomica and strychnine can be relied
+on. To give directly digestive material, hydrochloric acid,
+pepsin and rennet are prescribed in many forms, but where
+there is much vomiting ingluvin is more efficacious than pepsin.
+When farinaceous food is badly borne, diastase is helpful, given
+either before or with the meal. To prevent fermentation, phenol,
+creasote and sulpho-carbolate of soda are all extremely useful
+in skilled hands; and for intestinal decomposition and flatulent
+distension, bismuth salicylate with salol or &beta;-naphthol is much
+used. Cyllin, and charcoal in many forms, may be taken both
+for gastric and intestinal flatulence. But all these drugs, of
+proved value though they are, must be modified and combined
+to suit the special idiosyncrasy of the patient, and are therefore
+often worse than useless in inexperienced hands. The condition
+of the bowels must always have due attention.</p>
+
+<div class="condensed">
+<p>See also <span class="sc"><a href="#artlinks">Digestive Organs</a></span>; <span class="sc"><a href="#artlinks">Nutrition</a></span> and <span class="sc"><a href="#artlinks">Dietetics</a></span>.</p>
+</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1r" id="ft1r" href="#fa1r"><span class="fn">1</span></a> This aspect of the matter&mdash;&ldquo;buccal digestion&rdquo;&mdash;has been
+specially emphasized in recent years by Horace Fletcher of the
+United States, whose experience of the results of systematic &ldquo;chewing,&rdquo;
+confirmed by Sir M. Foster, Prof. Chittenden and others, has
+almost revolutionized the science of dietetics.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">DYSTELEOLOGY,<a name="ar13" id="ar13"></a></span> a modern word invented by Haeckel
+(<i>Evolution of Man</i>) for the doctrine of purposelessness, as
+opposed to the philosophical doctrine of design (Teleology).</p>
+
+
+<hr class="art" />
+<p><span class="bold">DZUNGARIA,<a name="ar14" id="ar14"></a></span> <span class="sc">Dsongaria</span>, or <span class="sc">Jungaria</span>, a former Mongolian
+kingdom of Central Asia, raised to its highest pitch by Kaldan
+or Bushtu Khan in the latter half of the 17th century, but
+completely destroyed by Chinese invasion about 1757-1759.
+It has played an important part in the history of Mongolia and
+the great migrations of Mongolian stems westward. Now its
+territory belongs partly to the Chinese empire (east Turkestan
+and north-western Mongolia) and partly to Russian Turkestan
+(provinces of Semiryechensk and Semipalatinsk). It derived
+its name from the Dsongars, or Songars, who were so called
+because they formed the left wing (<i>dson</i>, left; <i>gar</i>, hand) of the
+Mongolian army. Its widest limit included Kashgar, Yarkand,
+Khotan, the whole region of the T&rsquo;ien Shan, or Tian-shan,
+Mountains, and in short the greater proportion of that part of
+Central Asia which extends from 35° to 50° N. and from 72° to
+97° E. The name, however, is more properly applied only to
+the present Chinese province of T&rsquo;ien Shan-pei-lu and the country
+watered by the Ili. As a political or geographical term it has
+practically disappeared from the map; but the range of mountains
+stretching north-east along the southern frontier of the
+Land of the Seven Streams, as the district to the south-east of
+the Balkhash Lake is called, preserves the name of Dzungarian
+Range.</p>
+
+
+<hr class="art" />
+<p><span class="pagenum"><a name="page788" id="page788"></a>788</span></p>
+<p><span class="bold">E<a name="ar15" id="ar15"></a></span> The fifth symbol in the English alphabet occupies also
+the same position in Phoenician and in the other
+alphabets descended from Phoenician. As the Semitic
+alphabet did not represent vowels, E was originally an
+aspirate. Its earliest form, while writing is still from right to left,
+is <img style="width:22px; height:21px; vertical-align: middle;" src="images/img788a.jpg" alt="" />, the upright being continued some distance below the lowest
+of the cross-strokes. In some of the Greek alphabets it appears
+as <img style="width:14px; height:21px; vertical-align: middle;" src="images/img788b.jpg" alt="" /> with the upright prolonged at both top and bottom, but
+it soon took the form with which we are familiar, though in
+the earlier examples of this form the cross-strokes are not
+horizontal but drop at an angle, <img style="width:18px; height:29px; vertical-align: middle;" src="images/img788c.jpg" alt="" />. In Corinth and places
+under its early influence like Megara, or colonized from it like
+Corcyra, the symbol for <i>e</i> takes the form <img style="width:16px; height:24px; vertical-align: middle;" src="images/img788d.jpg" alt="" /> or <img style="width:15px; height:20px; vertical-align: middle;" src="images/img788e.jpg" alt="" />, while at Sicyon
+in the 6th and 5th centuries <span class="scs">B.C.</span> it is represented by <img style="width:14px; height:22px; vertical-align: middle;" src="images/img788f.jpg" alt="" />. In
+early Latin it was sometimes represented by two perpendicular
+strokes of equal length, <img style="width:13px; height:19px; vertical-align: middle;" src="images/img788g.jpg" alt="" />.</p>
+
+<p>In the earliest Greek inscriptions and always in Latin the
+symbol <img style="width:16px; height:18px; vertical-align: middle;" src="images/img788h.jpg" alt="" /> represented both the short and the long <i>e</i>-sound.
+In Greek also it was often used for the close long sound which
+arose either by contraction of two short <i>e</i>-sounds or by the loss
+of a consonant, after a short <i>e</i>-sound, as in <span class="grk" title="phileite">&#966;&#953;&#955;&#949;&#8150;&#964;&#949;</span>, &ldquo;you love,&rdquo;
+for <span class="grk" title="phileete">&#966;&#953;&#955;&#941;&#949;&#964;&#949;</span>, and <span class="grk" title="phaeinos">&#966;&#945;&#949;&#953;&#957;&#972;&#962;</span>, &ldquo;bright,&rdquo; out of an earlier <span class="grk" title="phaesnos">&#966;&#945;&#949;&#963;&#957;&#972;&#962;</span>.
+The Ionian Greeks of Asia Minor, who had altogether lost the
+aspirate, were the first to use the symbol <img style="width:18px; height:19px; vertical-align: middle;" src="images/img788i.jpg" alt="" /> for the long <i>e</i>-sound,
+and in official documents at Athens down to 403 <span class="scs">B.C.</span>, when the
+Greek alphabet as still known was adopted by the state, <img style="width:16px; height:18px; vertical-align: middle;" src="images/img788h.jpg" alt="" />
+represented &epsilon;, &eta; and the sound arising by contraction or consonant
+loss as mentioned above which henceforth was written with
+two symbols, <span class="grk" title="ei">&#949;&#953;</span>, and being really a single sound is known as
+the &ldquo;spurious diphthong.&rdquo; There were some minor distinctions
+in usage of the symbols <img style="width:16px; height:18px; vertical-align: middle;" src="images/img788h.jpg" alt="" /> and <img style="width:18px; height:19px; vertical-align: middle;" src="images/img788i.jpg" alt="" /> which need not here be given
+in detail. The ancient Greek name was <span class="grk" title="ei">&#949;&#7990;</span>, not <i>Epsilon</i> as
+popularly supposed; the names of the Greek letters are
+given from Kallias, an earlier contemporary of Euripides, in
+Athenaeus x. p. 453 d.</p>
+
+<p>In Greek the short <i>e</i>-sound to which <img style="width:16px; height:18px; vertical-align: middle;" src="images/img788h.jpg" alt="" /> was ultimately limited
+was a close sound inclining more towards <i>i</i> than <i>a</i>; hence the
+representation of the contraction of <span class="grk" title="ee">&#949;&#949;</span> by <span class="grk" title="ei">&#949;&#953;</span>. Its value in
+Latin was exactly the opposite, the Latin short <i>e</i> being open,
+and the long close. In English there has been a gradual
+narrowing of the long vowels, <i>&#257;</i> becoming approximately <i>&#275;i</i>
+and <i>&#275;</i> becoming <i>&#299;</i> (Sweet, <i>History of English Sounds</i>, §§ 781, 817 ff.
+2nd ed.). In languages where the diphthong <i>ai</i> has become a
+monophthong, the resulting sound is some variety of long <i>e</i>.
+Often the gradual assimilation can be traced through the intermediate
+stage of <i>ae</i> to <i>&#275;</i>, as in the Old Latin <i>aidilis</i>, which in
+classical Latin is <i>aedilis</i>, and in medieval MSS. <i>edilis</i>.</p>
+
+<p>The variety of spelling in English for the long and short <i>e</i>-sounds
+is conveniently illustrated in Miss Soames&rsquo;s <i>Introduction
+to the Study of Phonetics</i>, pp. 16 and 20.</p>
+<div class="author">(P. Gi.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EA<a name="ar16" id="ar16"></a></span> (written by means of two signs signifying &ldquo;house&rdquo;
+and &ldquo;water&rdquo;), in the Babylonian religion, originally the patron
+deity of Eridu, situated in ancient times at the head of the Persian
+Gulf, but now, by reason of the constant accumulation of soil
+in the Euphrates valley, at some distance from the gulf. Eridu,
+meaning &ldquo;the good city,&rdquo; was one of the oldest settlements in
+the Euphrates valley, and is now represented by the mounds
+known as Abu Shahrein. In the absence of excavations on that
+site, we are dependent for our knowledge of Ea on material
+found elsewhere. This is, however, sufficient to enable us to
+state definitely that Ea was a water-deity, and there is every
+reason to believe that the Persian Gulf was the body of water
+more particularly sacred to him. Whether Ea (or A-e as some
+scholars prefer) represents the real pronunciation of his name
+we do not know. All attempts to connect Ea with Yah and
+Yahweh are idle conjectures without any substantial basis.
+He is figured as a man covered with the body of a fish, and this
+representation, as likewise the name of his temple E-apsu,
+&ldquo;house of the watery deep,&rdquo; points decidedly to his character
+as a god of the waters (see <span class="sc"><a href="#artlinks">Oannes</a></span>). Of his cult at Eridu, which
+reverts to the oldest period of Babylonian history, nothing
+definite is known beyond the fact that the name of his temple
+was E-saggila, &ldquo;the lofty house&rdquo;&mdash;pointing to a staged tower
+as in the case of the temple of Bel (<i>q.v.</i>) at Nippur, known as
+E-Kur, <i>i.e.</i> &ldquo;mountain house&rdquo;&mdash;and that incantations, involving
+ceremonial rites, in which water as a sacred element played
+a prominent part, formed a feature of his worship. Whether
+Eridu at one time also played an important political rôle is not
+certain, though not improbable. At all events, the prominence
+of the Ea cult led, as in the case of Nippur, to the survival of
+Eridu as a sacred city, long after it had ceased to have any
+significance as a political centre. Myths in which Ea figures
+prominently have been found in Assur-bani-pal&rsquo;s library, indicating
+that Ea was regarded as the protector and teacher of
+mankind. He is essentially a god of civilization, and it was natural
+that he was also looked upon as the creator of man, and of the
+world in general. Traces of this view appear in the Marduk epic
+celebrating the achievements of this god, and the close connexion
+between the Ea cult at Eridu and that of Marduk also follows
+from two considerations: (1) that the name of Marduk&rsquo;s sanctuary
+at Babylon bears the same name, E-saggila, as that of Ea
+in Eridu, and (2) that Marduk is generally termed the son of Ea,
+who derives his powers from the voluntary abdication of the
+father in favour of his son. Accordingly, the incantations
+originally composed for the Ea cult were re-edited by the priests
+of Babylon and adapted to the worship of Marduk, and, similarly,
+the hymns to Marduk betray traces of the transfer of attributes
+to Marduk which originally belonged to Ea.</p>
+
+<p>It is, however, more particularly as the third figure in the triad,
+the two other members of which were Anu (<i>q.v.</i>) and Bel (<i>q.v.</i>),
+that Ea acquires his permanent place in the pantheon. To him
+was assigned the control of the watery element, and in this
+capacity he becomes the <i>shar apsi</i>, <i>i.e.</i> king of the Apsu or &ldquo;the
+deep.&rdquo; The Apsu was figured as an ocean encircling the earth,
+and since the gathering place of the dead, known as Ar&#257;lu, was
+situated near the confines of the Apsu, he was also designated
+as En-Ki, <i>i.e.</i> &ldquo;lord of that which is below,&rdquo; in contrast to Anu,
+who was the lord of the &ldquo;above&rdquo; or the heavens. The cult
+of Ea extended throughout Babylonia and Assyria. We find
+temples and shrines erected in his honour, <i>e.g.</i> at Nippur, Girsu,
+Ur, Babylon, Sippar and Nineveh, and the numerous epithets
+given to him, as well as the various forms under which the god
+appears, alike bear witness to the popularity which he enjoyed
+from the earliest to the latest period of Babylonian-Assyrian
+history. The consort of Ea, known as Damkina, &ldquo;lady of that
+which is below,&rdquo; or Nin-Ki, having the same meaning, or
+Damgal-nunna, &ldquo;great lady of the waters,&rdquo; represents a pale
+reflection of Ea and plays a part merely in association with
+her lord.</p>
+<div class="author">(M. Ja.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EABANI,<a name="ar17" id="ar17"></a></span> the name of the friend of Gilgamesh, the hero in the
+Babylonian epic (see <span class="sc"><a href="#artlinks">Gilgamesh, Epic of</a></span>). Eabani, whose
+name signifies &ldquo;Ea creates,&rdquo; pointing to the tradition which
+made the god Ea (<i>q.v.</i>) the creator of mankind, is represented
+in the epic as the type of the primeval man. He is a wild man
+who lives with the animals of the field until lured away from his
+surroundings by the charms of a woman. Created to become
+a rival to Gilgamesh, he strikes up a friendship with the hero, and
+together they proceed to a cedar forest guarded by Khumbaba,
+whom they kill. The goddess Irnina (a form of Ishtar, <i>q.v.</i>)
+in revenge kills Eabani, and the balance of the epic is taken
+up with Gilgamesh&rsquo;s lament for his friend, his wanderings in
+quest of a remote ancestor, Ut-Napishtim, from whom he
+hopes to learn how he may escape the fate of Eabani,
+and his finally learning from his friend of the sad fate in
+store for all mortals except the favourites of the god, like
+<span class="pagenum"><a name="page789" id="page789"></a>789</span>
+Ut-Napishtim, to whom immortal life is vouchsafed as a
+special boon.</p>
+<div class="author">(M. Ja.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EACHARD, JOHN<a name="ar18" id="ar18"></a></span> (1636?-1697), English divine, was born in
+Suffolk, and was educated at Catharine Hall, Cambridge, of
+which he became master in 1675 in succession to John Lightfoot.
+He was created D.D. in 1676 by royal mandate, and was twice
+(in 1679 and 1695) vice-chancellor of the university. He died
+on the 7th of July 1697. In 1670 he had published anonymously
+a humorous satire entitled <i>The Ground and Occasions of the
+Contempt of the Clergy enquired into in a letter to R. L.</i>, which
+excited much attention and provoked several replies, one of them
+being from John Owen. These were met by <i>Some Observations,
+&amp;c., in a second letter to R. L.</i> (1671), written in the same bantering
+tone as the original work. Eachard attributed the contempt
+into which the clergy had fallen to their imperfect education,
+their insufficient incomes, and the want of a true vocation.
+His descriptions, which were somewhat exaggerated, were
+largely used by Macaulay in his <i>History of England</i>. He gave
+amusing illustrations of the absurdity and poverty of the current
+pulpit oratory of his day, some of them being taken from the
+sermons of his own father. He attacked the philosophy of Hobbes
+in his <i>Mr Hobb&rsquo;s State of Nature considered; in a dialogue
+between Philautus and Timothy</i> (1672), and in his <i>Some Opinions
+of Mr Hobbs considered in a second dialogue</i> (1673). These were
+written in their author&rsquo;s chosen vein of light satire, and Dryden
+praised them as highly effective within their own range.
+Eachard&rsquo;s own sermons, however, were not superior to those
+he satirized. Swift (<i>Works</i>, xii. 279) alludes to him as a signal
+instance of a successful humorist who entirely failed as a serious
+writer.</p>
+
+<div class="condensed">
+<p>A collected edition of his works in three volumes, with a notice
+of his life, was published in 1774. The <i>Contempt of the Clergy</i> was
+reprinted in E. Arber&rsquo;s <i>English Garner</i>. <i>A Free Enquiry into the
+Causes of the very great Esteem that the Nonconforming Preachers
+are generally in with their Followers</i> (1673) has been attributed to
+Eachard on insufficient grounds.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EADBALD<a name="ar19" id="ar19"></a></span> (d. 640), king of Kent, succeeded to the throne
+on the death of his father Æthelberht in 616. He had not been
+influenced by the teaching of the Christian missionaries, and
+his first step on his accession was to marry his father&rsquo;s widow.
+After his subsequent conversion by Laurentius, archbishop of
+Canterbury, he recalled the bishops Mellitus and Justus, and built
+a church dedicated to the Virgin at Canterbury. He arranged
+a marriage between his sister Æthelberg and Edwin of Northumbria,
+on whose defeat and death in 633 he received his sister and
+Paulinus, and offered the latter the bishopric of Rochester.
+Eadbald married Emma, a Frankish princess, and died on the
+20th of January 640.</p>
+
+<div class="condensed">
+<p>See Bede, <i>Historia ecclesiastica</i> (ed. C. Plummer, Oxford, 1896);
+<i>Saxon Chronicle</i> (ed. J. Earle and C. Plummer, Oxford, 1899).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EADIE, JOHN<a name="ar20" id="ar20"></a></span> (1810-1876), Scottish theologian and biblical
+critic, was born at Alva, in Stirlingshire, on the 9th of May 1810.
+Having taken the arts curriculum at Glasgow University, he
+studied for the ministry at the Divinity Hall of the Secession
+Church, a dissenting body which, on its union a few years later
+with the Relief Church, adopted the title United Presbyterian.
+In 1835 he became minister of the Cambridge Street Secession
+church in Glasgow, and for many years he was generally regarded
+as the leading representative of his denomination in Glasgow.
+As a preacher, though he was not eloquent, he was distinguished
+by good sense, earnestness and breadth of sympathy. In 1863
+he removed with a portion of his congregation to a new church
+at Lansdowne Crescent. In 1843 Eadie was appointed professor
+of biblical literature and hermeneutics in the Divinity Hall of
+the United Presbyterian body. He held this appointment along
+with his ministerial charge till the close of his life. Though
+not a profound scholar, he was surpassed by few biblical commentators
+of his day in range of learning, and in soundness of
+judgment. In the professor&rsquo;s chair, as in the pulpit, his strength
+lay in the tact with which he selected the soundest results of
+biblical criticism, whether his own or that of others, and presented
+them in a clear and connected form, with a constant view
+to their practical bearing. He received the degree of LL.D.
+from Glasgow in 1844, and that of D.D. from St Andrews in
+1850.</p>
+
+<p>His publications were connected with biblical criticism and
+interpretation, some of them being for popular use and others
+more strictly scientific. To the former class belong the <i>Biblical
+Cyclopaedia</i>, his edition of <i>Cruden&rsquo;s Concordance</i>, his <i>Early
+Oriental History</i>, and his discourses on the <i>Divine Love</i> and on
+<i>Paul the Preacher</i>; to the latter his commentaries on the Greek
+text of St Paul&rsquo;s epistles to the Ephesians, Colossians, Philippians
+and Galatians, published at intervals in four volumes. His last
+work was the <i>History of the English Bible</i> (2 vols., 1876). He
+rendered good service as one of the revisers of the authorized
+version. He died at Glasgow on the 3rd of June 1876. His
+valuable library was bought and presented to the United Presbyterian
+College.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EADMER,<a name="ar21" id="ar21"></a></span> or <span class="sc">Edmer</span> (<i>c.</i> 1060-<i>c.</i> 1124), English historian and
+ecclesiastic, was probably, as his name suggests, of English,
+and not of Norman parentage. He became a monk in the
+Benedictine monastery of Christ Church, Canterbury, where
+he made the acquaintance of Anselm, at that time visiting
+England as abbot of Bec. The intimacy was renewed when
+Anselm became archbishop of Canterbury in 1093; thenceforward
+Eadmer was not only his disciple and follower, but his
+friend and director, being formally appointed to this position
+by Pope Urban II. In 1120 he was nominated to the archbishopric
+of St Andrews, but as the Scots would not recognize
+the authority of the see of Canterbury he was never consecrated,
+and soon afterwards he resigned his claim to the archbishopric.
+His death is generally assigned to the year 1124.</p>
+
+<p>Eadmer left a large number of writings, the most important
+of which is his <i>Historiae novorum</i>, a work which deals mainly
+with the history of England between 1066 and 1122. Although
+concerned principally with ecclesiastical affairs scholars agree
+in regarding the <i>Historiae</i> as one of the ablest and most valuable
+writings of its kind. It was first edited by John Selden in 1623
+and, with Eadmer&rsquo;s <i>Vita Anselmi</i>, has been edited by Martin
+Rule for the &ldquo;Rolls Series&rdquo; (London, 1884). The <i>Vita Anselmi</i>,
+first printed at Antwerp in 1551, is probably the best life of the
+saint. Less noteworthy are Eadmer&rsquo;s lives of St Dunstan, St
+Bregwin, archbishop of Canterbury, and St Oswald, archbishop
+of York; these are all printed in Henry Wharton&rsquo;s <i>Anglia Sacra</i>,
+part ii. (1691), where a list of Eadmer&rsquo;s writings will be found.
+The manuscripts of most of Eadmer&rsquo;s works are preserved in
+the library of Corpus Christi College, Cambridge.</p>
+
+<div class="condensed">
+<p>See M. Rule, <i>On Eadmer&rsquo;s Elaboration of the first four Books of
+&ldquo;Historiae novorum&rdquo;</i> (1886); and Père Ragey, <i>Eadmer</i> (Paris, 1892).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EADS, JAMES BUCHANAN<a name="ar22" id="ar22"></a></span> (1820-1887), American engineer,
+was born at Lawrenceburg, Indiana, on the 23rd of May 1820.
+His first engineering work of any importance was in raising
+sunken steamers. In 1845 he established glass works in St Louis.
+During the Civil War he constructed ironclad steamers and
+mortar boats for the Federal government. His next important
+engineering achievement was the construction of the great steel
+arch bridge across the Mississippi at St Louis (see <span class="sc"><a href="#artlinks">Bridge</a></span>, fig.
+29), upon which he was engaged from 1867 till 1874. The
+work, however, upon which his reputation principally rests
+was his deepening and fixing the channel at the mouths of the
+Mississippi by means of jetties, whereby the narrowed stream
+was made to scour out its own channel and carry the sediment
+out to sea. Shortly before his death he projected a scheme for
+a ship railway across the Isthmus of Tehuantepec, in lieu of an
+isthmian canal. He died at Nassau, in the Bahamas, on the
+8th of March 1887.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAGLE<a name="ar23" id="ar23"></a></span> (Fr. <i>aigle</i>, from the Lat. <i>aquila</i>), the name generally
+given to the larger diurnal birds of prey which are not vultures;
+but the limits of the subfamily <i>Aquilinae</i> have been very variously
+assigned by different writers on systematic ornithology, and there
+are eagles smaller than certain buzzards. By some authorities
+the <i>Laemmergeier</i> of the Alps, and other high mountains of
+Europe, North Africa and Asia, is accounted an eagle, but by
+others the genus <i>Gypaetus</i> is placed with the <i>Vulturidae</i> as its
+<span class="pagenum"><a name="page790" id="page790"></a>790</span>
+common English name (bearded vulture) shows. There are also
+other forms, such as the South American <i>Harpyia</i> and its allies,
+which though generally called eagles have been ranked as buzzards.
+In the absence of any truly scientific definition of the family
+<i>Aquilinae</i> it is best to leave these and many other more or less
+questionable members of the group&mdash;such as the genera <i>Spizaetus</i>,
+<i>Circaetus</i>, <i>Spilornis</i>, <i>Helotarsus</i>, and so forth&mdash;and to treat here
+of those whose position cannot be gainsaid.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:408px; height:580px" src="images/img790a.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 1.</span>&mdash;Sea-Eagle.</td></tr></table>
+
+<p>True eagles inhabit all the regions of the world, and some seven
+or eight species at least are found in Europe, of which two are
+resident in the British Islands. In England and in the Lowlands
+of Scotland eagles only exist as stragglers; but in the Hebrides
+and some parts of the Highlands a good many may yet be found,
+and their numbers appear to have rather increased of late years
+than diminished; for the foresters and shepherds, finding that
+a high price can be got for their eggs, take care to protect the
+owners of the eyries, which are nearly all well known, and to keep
+up the stock by allowing them at times to rear their young.
+There are also now not a few occupiers of Scottish forests who
+interfere so far as they can to protect the king of birds.<a name="fa1a" id="fa1a" href="#ft1a"><span class="sp">1</span></a> In
+Ireland the extirpation of eagles seems to have been carried on
+almost unaffected by the prudent considerations which in the
+northern kingdom have operated so favourably for the race, and
+except in the wildest parts of Donegal, Mayo and Kerry, eagles
+in the sister island are almost birds of the past.</p>
+
+<p>Of the two British species the erne (Icel. <i>&OElig;rn</i>) or sea-eagle
+(by some called also the white-tailed and cinereous eagle)&mdash;<i>Haliaetus
+albicilla</i>&mdash;affects chiefly the coast and neighbourhood
+of inland waters, living in great part on the fish and refuse that is
+thrown up on the shore, though it not unfrequently takes living
+prey, such as lambs, hares and rabbits. On these last, indeed,
+young examples mostly feed when they wander southward in
+autumn, as they yearly do, and appear in England. The adults
+(fig. 1) are distinguished by their prevalent greyish-brown colour,
+their pale head, yellow beak and white tail&mdash;characters, however,
+wanting in the immature, which do not assume the perfect
+plumage for some three or four years. The eyry is commonly
+placed in a high cliff or on an island in a lake&mdash;sometimes on the
+ground, at others in a tree&mdash;and consists of a vast mass of sticks
+in the midst of which is formed a hollow lined with <i>Luzula
+sylvatica</i> (as first observed by John Wolley) or some similar
+grass, and here are laid the two or three white eggs. In former
+days the sea-eagle seems to have bred in several parts of England&mdash;as
+the Lake district, and possibly even in the Isle of Wight
+and on Dartmoor. This species inhabits all the northern part of
+the Old World from Iceland to Kamchatka, and breeds in Europe
+so far to the southward as Albania. In the New World, however,
+it is only found in Greenland, being elsewhere replaced by the
+white-headed or bald eagle, <i>H. leucocephalus</i>, a bird of similar
+habits, and the chosen emblem of the United States of America.
+In the far east of Asia occurs a still larger and finer sea-eagle,
+<i>H. pelagicus</i>, remarkable for its white thighs and upper wing-coverts.
+South-eastern Europe and India furnish a much smaller
+species, <i>H. leucoryphus</i>, which has its representative, <i>H. leucogaster</i>,
+in the Malay Archipelago and Australia, and, as allies in South
+Africa and Madagascar, <i>H. vocifer</i> and <i>H. vociferoides</i> respectively.
+All these eagles may be distinguished by their scaly tarsi, while
+the group next to be treated of have the tarsi feathered to the
+toes.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:512px; height:555px" src="images/img790b.jpg" alt="" /></td></tr>
+<tr><td class="caption"><span class="sc">Fig. 2.</span>&mdash;Mountain-Eagle.</td></tr></table>
+
+<p>The golden or mountain eagle, <i>Aquila chrysaetus</i>, is the second
+British species. This also formerly inhabited England, and a nest,
+found in 1668 in the Peak of Derbyshire, is well described by
+Willughby, in whose time it was said to breed also in the Snowdon
+range. It seldom if ever frequents the coast, and is more active
+on the wing than the sea-eagle, being able to take some birds
+as they fly, but a large part of its sustenance is the flesh of animals
+that die a natural death. Its eyry is generally placed and built
+like that of the other British species,<a name="fa2a" id="fa2a" href="#ft2a"><span class="sp">2</span></a> but the neighbourhood of
+<span class="pagenum"><a name="page791" id="page791"></a>791</span>
+water is not requisite. The eggs, from two to four in number,
+vary from a pure white to a mottled, and often highly coloured,
+surface, on which appear different shades of red and purple.
+The adult bird (fig. 2) is of a rich dark brown, with the elongated
+feathers of the neck, especially on the nape, light tawny, in which
+imagination sees a &ldquo;golden&rdquo; hue, and the tail marbled with
+brown and ashy-grey. In the young the tail is white at the base,
+and the neck has scarcely any tawny tint. The golden eagle
+does not occur in Iceland, but occupies suitable situations over
+the rest of the Palaearctic Region and a considerable portion of
+the Nearctic&mdash;though the American bird has been, by some,
+considered a distinct species. Domesticated, it has many times
+been trained to take prey for its master in Europe, and to this
+species is thought to belong an eagle habitually used by the
+Kirghiz Tatars, who call it <i>Bergut</i> or <i>Bearcoot</i>, for the capture
+of antelopes, foxes and wolves. It is carried hooded on horseback
+or on a perch between two men, and released when the quarry
+is in sight. Such a bird, when well trained, is valued, says
+P.S. Pallas, at the price of two camels. It is quite possible,
+however, that more than one kind of eagle is thus used, and the
+services of <i>A. heliaca</i> (which is the imperial eagle of some
+writers<a name="fa3a" id="fa3a" href="#ft3a"><span class="sp">3</span></a>) and of <i>A. mogilnik</i>&mdash;both of which are found in
+central Asia, as well as in south-eastern Europe&mdash;may also be
+employed.</p>
+
+<p>A smaller form of eagle, which has usually gone under the
+name of <i>A. naevia</i>, is now thought by the best authorities to
+include three local races, or, in the eyes of some, species. They
+inhabit Europe, North Africa and western Asia to India, and two
+examples of one of them&mdash;<i>A. clanga</i>, the form which is somewhat
+plentiful in north-eastern Germany&mdash;have occurred in Cornwall.
+The smallest true eagle is <i>A. pennata</i>, which inhabits southern
+Europe, Africa and India. Differing from other eagles of their
+genus by its wedge-shaped tail, though otherwise greatly resembling
+them, is the <i>A. audax</i> of Australia. Lastly may be
+noticed here a small group of eagles, characterized by their
+long legs, forming the genus <i>Nisaetus</i>, of which one species,
+<i>N. fasciatus</i>, is found in Europe.</p>
+<div class="author">(A. N.)</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1a" id="ft1a" href="#fa1a"><span class="fn">1</span></a> Lord Breadalbane (d. 1871) was perhaps the first large landowner
+who set the example that has been since followed by others. On his
+unrivalled forest of Black Mount, eagles&mdash;elsewhere persecuted to
+the death&mdash;were by him ordered to be unmolested so long as they
+were not numerous enough to cause considerable depredations on the
+farmers&rsquo; flocks. He thought that the spectacle of a soaring eagle
+was a fitting adjunct to the grandeur of his Argyllshire mountain
+scenery, and a good equivalent for the occasional loss of a lamb,
+or the slight deduction from the rent paid by his tenantry in
+consequence.</p>
+
+<p><a name="ft2a" id="ft2a" href="#fa2a"><span class="fn">2</span></a> As already stated, the site chosen varies greatly. Occasionally
+placed in a niche in what passes for a perpendicular cliff to which
+access could only be gained by a skilful cragsman with a rope, the
+writer has known a nest to within 10 or 15 yds. of which he rode on
+a pony. Two beautiful views of as many golden eagles&rsquo; nests,
+drawn on the spot by Joseph Wolf, are given in the <i>Ootheca Wolleyana</i>,
+and a fine series of eggs is also figured in the same work.</p>
+
+<p><a name="ft3a" id="ft3a" href="#fa3a"><span class="fn">3</span></a> Which species may have been the traditional emblem of Roman
+power, and the <i>Ales Jovis</i>, is very uncertain.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EAGLEHAWK,<a name="ar24" id="ar24"></a></span> a borough of Bendigo county, Victoria,
+Australia, 105 m. by rail N.N.W. of Melbourne and 4 m. from
+Bendigo, with which it is connected by steam tramway. Pop.
+(1901) 8130. It stands on the Bendigo gold-bearing reef, and its
+mines are important.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAGRE<a name="ar25" id="ar25"></a></span> (a word of obscure origin; the earliest form seems
+to be <i>higre</i>, Latinized as <i>higra</i>, which William of Malmesbury
+gives as the name of the bore in the Severn; the <i>New English
+Dictionary</i> rejects the usual derivations from the O. Eng. <i>eagor</i>
+or <i>egor</i>, which is seen in compounds meaning &ldquo;flood,&rdquo; and
+also the connexion with the Norse sea-god <i>Aegir</i>), a tide wave
+of great height rushing up an estuary (see <span class="sc"><a href="#artlinks">Bore</a></span>), used locally
+of the Humber and Trent.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAKINS, THOMAS<a name="ar26" id="ar26"></a></span> (1844-&emsp;&emsp;), American portrait and figure
+painter, was born at Philadelphia, on the 25th of July 1844.
+A pupil of J.L. Gérôme, in the École des Beaux-Arts, Paris, and
+Also of Léon Bonnat, besides working in the studio of the sculptor
+Dumont, he became a prolific portrait painter. He also painted
+genre pictures, sending to the Centennial Exhibition at Philadelphia,
+in 1876, the &ldquo;Chess Players,&rdquo; now in the Metropolitan
+Museum of Art, New York. A large canvas, &ldquo;The Surgical
+Clinic of Professor Gross,&rdquo; owned by Jefferson Medical College,
+Philadelphia, contains many life-sized figures. Eakins, with
+his pupil Samuel Murray (b. 1870), modelled the heroic
+&ldquo;Prophets&rdquo; for the Witherspoon Building, Philadelphia, and
+his work in painting has a decided sculptural quality. He was
+for some years professor of anatomy at the schools of the Pennsylvania
+Academy of Fine Arts in Philadelphia. A man of great
+inventiveness, he experimented in many directions, depicting
+on canvas modern athletic sports, the negro, and early American
+life, but he is best known by his portraits. He received awards
+at the Columbian (1893), Paris (1900), Pan-American (1900),
+and the St Louis (1904), Expositions; and won the Temple
+medal in the Pennsylvania Academy of Fine Arts, and the
+Proctor prize of the National Academy of Design.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EALING,<a name="ar27" id="ar27"></a></span> a municipal borough in the Ealing parliamentary
+division of Middlesex, England, suburban to London, 9 m. W.
+of St Paul&rsquo;s cathedral. Pop. (1891) 23,979; (1901) 33,031.
+The nucleus of the town, the ancient village, lies south of the
+highroad to Uxbridge, west of the open Ealing Common. The
+place is wholly residential. At St Mary&rsquo;s church, almost wholly
+rebuilt c. 1870, are buried John Oldmixon, the historian (d. 1742),
+and Horne Tooke (d. 1812). The church of All Saints (1905) commemorates
+Spencer Perceval, prime minister, who was assassinated
+in the House of Commons in 1812. It was erected under
+the will of his daughter Frederica, a resident of Ealing. Gunnersbury
+Park, south of Ealing Common, is a handsome Italian
+mansion. Among former owners of the property was Princess
+Amelia, daughter of George II., who lived here from 1761 till
+her death in 1786. The name of Gunnersbury is said to be
+traceable to the residence here of Gunilda, niece of King Canute.
+The manor of Ealing early belonged to the see of London, but
+it is not mentioned in Domesday and its history is obscure.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAR<a name="ar28" id="ar28"></a></span> (common Teut.; O.E. <i>éare</i>, Ger. <i>Ohr</i>, Du. <i>oor</i>, akin to
+Lat. <i>auris</i>, Gr. <span class="grk" title="ous">&#959;&#8022;&#962;</span>), in anatomy, the organ of hearing.
+The human ear is divided into three parts&mdash;external, middle
+and internal. The external ear consists of the pinna and the
+external auditory meatus. The pinna is composed of a yellow
+fibro-cartilaginous framework covered by skin, and has an
+external and an internal or cranial surface. Round the margin
+of the external surface in its upper three quarters is a rim called
+the helix (fig. 1, <i>a</i>), in which is often seen a little prominence
+known as Darwin&rsquo;s tubercle, representing the folded-over apex
+of a prick-eared ancestor. Concentric with the helix and nearer
+the meatus is the antihelix (<i>c</i>), which, above, divides into two
+limbs to enclose the triangular fossa of the antihelix. Between
+the helix and the antihelix is the fossa of the helix. In front
+of the antihelix is the deep fossa known as the concha (fig. 1, <i>d</i>),
+and from the anterior part of this the meatus passes inward
+into the skull. Overlapping the meatus from in front is a flap
+called the tragus, and below and behind this is another smaller
+flap, the antitragus. The lower part of the pinna is the lobule
+(<i>e</i>), which contains no cartilage. On the cranial surface of the
+pinna elevations correspond to the concha and to the fossae
+<span class="pagenum"><a name="page792" id="page792"></a>792</span>
+of the helix and antihelix. The pinna can be slightly moved by
+the anterior, superior and posterior auricular muscles, and in
+addition to these there are four small intrinsic muscles on the
+external surface, known as the helicis major and minor, the
+tragicus and the antitragicus, and two on the internal surface
+called the obliquus and transversus. The external auditory
+meatus (fig. 1, <i>n</i>) is a tube running at first forward and upward,
+then a little backward and then forward and slightly downward;
+of course all the time it is also running inward until the tympanic
+membrane is reached. The tube is about an inch long, its outer
+third being cartilaginous and its inner two-thirds bony. It is
+lined by skin in its whole length, the sweat glands of which are
+modified to secrete the wax or cerumen.</p>
+
+<table class="pic" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter" colspan="2"><img style="width:454px; height:381px" src="images/img791.jpg" alt="" /></td></tr>
+<tr><td class="caption" colspan="2"><span class="sc">Fig. 1.</span>&mdash;The Ear as seen in Section.</td></tr>
+
+<tr><td class="f90" style="width: 50%; vertical-align: top;">
+<p><i>a</i>, Helix.</p>
+<p><i>b</i>, Antitragus.</p>
+<p><i>c</i>, Antihelix.</p>
+<p><i>d</i>, Concha.</p>
+<p><i>e</i>, Lobule.</p>
+<p><i>f</i>, Mastoid process.</p>
+<p><i>g</i>, Portio dura.</p>
+<p><i>h</i>, Styloid process.</p>
+<p><i>k</i>, Internal carotid artery.</p>
+<p><i>l</i>, Eustachian tube.</p></td>
+
+<td class="f90" style="width: 50%; vertical-align: top;">
+<p><i>m</i>, Tip of petrous process.</p>
+<p><i>n</i>, External auditory meatus.</p>
+<p><i>o</i>, Membrana tympani.</p>
+<p><i>p</i>, Tympanum.</p>
+<p>1, points to malleus.</p>
+<p>2, to incus.</p>
+<p>3, to stapes.</p>
+<p>4, to cochlea.</p>
+<p>5, 6, 7, the three semicircular canals.</p>
+<p>8 and 9, facial and auditory nerves.</p></td></tr></table>
+
+<p>The middle ear or tympanum (fig. 1, <i>p</i>) is a small cavity in the
+temporal bone, the shape of which may perhaps be realized by
+imagining a hock bottle subjected to lateral pressure in such a
+way that its circular section becomes triangular, the base of the
+triangle being above. The neck of the bottle, also laterally
+compressed, will represent the Eustachian tube (fig. 1, <i>l</i>), which
+runs forward, inward and downward, to open into the
+naso-pharynx, and so admits air into the tympanum. The bottom
+of the bottle will represent the posterior wall of the tympanum,
+from the upper part of which an opening leads backward into
+the mastoid antrum and so into the air-cells of the mastoid
+process. Lower down is a little pyramid which transmits the
+stapedius muscle, and at the base of this is a small opening known
+as the iter chordae posterius, for the chorda tympani to come
+through from the facial nerve. The roof is formed by a very
+thin plate of bone, called the tegmen tympani, which separates
+the cavity from the middle fossa of the skull. Below the roof
+the upper part of the tympanum is somewhat constricted off
+from the rest, and to this part the term &ldquo;attic&rdquo; is often applied.
+The floor is a mere groove formed by the meeting of the external
+and internal walls. The outer wall is largely occupied by the
+tympanic membrane (fig. 1, <i>o</i>), which entirely separates the
+middle ear from the external auditory meatus; it is circular,
+and so placed that it slopes from above, downward and inward,
+and from behind, forward and inward. Externally it is lined
+by skin, internally by mucous membrane, while between the
+two is a firm fibrous membrane, convex inward about its centre
+to form the umbo. Just in front of the membrane on the outer
+wall is the Glaserian fissure leading to the glenoid cavity, and
+close to this is the canal of Huguier for the chorda tympani
+nerve. The inner wall shows a promontory caused by the
+cochlea and grooved by the tympanic plexus of nerves; above
+and behind it is the fenestra ovalis, while below and behind the
+fenestra rotunda is seen, closed by a membrane. Curving round,
+above and behind the promontory and fenestrae, is a ridge
+caused by the aqueductus Fallopii or canal for the facial nerve.
+The whole tympanum is about half an inch from before backward,
+and half an inch high, and is spanned from side to side by three
+small bones, of which the malleus (fig. 1, 1) is the most external.
+This is attached by its handle to the umbo of the tympanic membrane,
+while its head lies in the attic and articulates posteriorly
+with the upper part of the next bone or incus (fig. 1, 2). The
+long process of the incus runs downward and ends in a little
+knob called the os orbiculare, which is jointed on to the stapes
+or stirrup bone (fig. 1, 3). The two branches of the stapes are
+anterior and posterior, while the footplate fits into the fenestra
+ovalis and is bound to it by a membrane. It will thus be seen
+that the stapes lies nearly at right angles to the long process
+of the incus. From the front of the malleus a slender process
+projects forward into the Glaserian fissure, while from the back
+of the incus the posterior process is directed backward and is
+attached to the posterior wall of the tympanum. These two
+processes form a fulcrum by which the lever action of the malleus
+and incus is brought about, so that when the handle of the
+malleus is pushed in by the membrane the head moves out;
+the top of the incus, attached to it, also moves out, and the os
+orbiculare moves in, and so the stapes is pressed into the fenestra
+ovalis. The stapedius and tensor tympanic muscles, the latter
+of which enters the tympanum in a canal just above the
+Eustachian tube to be attached to the malleus, modify the
+movements of the ossicles.</p>
+
+<p>The mucous membrane lining the tympanum is continuous
+through the Eustachian tube with that of the naso-pharynx,
+and is reflected on to the ossicles, muscles and chorda tympani
+nerve. It is ciliated except where it covers the membrana
+tympani, ossicles and promontory; here it is stratified.</p>
+
+<table class="flt" style="float: right; width: 330px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:276px; height:161px" src="images/img792a.jpg" alt="" /></td></tr>
+<tr><td class="caption1"><span class="sc">Fig. 2.</span>&mdash;Diagram of the Membranous
+Labyrinth.</td></tr>
+<tr><td class="caption1">
+<p>DC, Ductus cochlearis.</p>
+<p><i>dr</i>, Ductus reuniens.</p>
+<p>S, Sacculus.</p>
+<p>U, Utriculus.</p>
+<p><i>dv</i>, Ductus endolymphaticus.</p>
+<p>SC, Semicircular canals.</p>
+<p>&emsp;&emsp;(After Waldeyer.)</p></td></tr></table>
+
+<p>The internal ear or labyrinth consists of a bony and a membranous
+part, the latter of which is contained in the former.
+The bony labyrinth is composed of the vestibule, the semicircular
+canals and the cochlea. The vestibule lies just internal
+to the posterior part of the tympanum, and there would be a
+communication between the two, through the fenestra ovalis,
+were it not that the footplate
+of the stapes blocks the
+way. The inner wall of the
+vestibule is separated from
+the bottom of the internal
+auditory meatus by a plate
+of bone pierced by many
+foramina for branches of the
+auditory nerve (fig. 1, 9),
+while at the lower part is the
+opening of the aqueductus
+vestibuli, by means of which
+a communication is established
+with the posterior
+cranial fossa. Posteriorly
+the three semicircular canals
+open into the vestibule; of
+these the external (fig. 1, 7) has two independent openings, but
+the superior and posterior (fig. 1, 5 and 6) join together at one
+end and so have a common opening, while at their other ends they
+open separately. The three canals have therefore five openings
+into the vestibule instead of six. One end of each canal is dilated
+to form its ampulla. The superior semicircular canal is vertical,
+and the two pillars of its arch are nearly external and internal;
+the external canal is horizontal, its two pillars being anterior and
+posterior, while the convexity of the arch of the posterior canal
+is backward and its two pillars are superior and inferior.
+Anteriorly the vestibule leads into the
+cochlea (fig. 1, 4), which is twisted two
+and a half times round a central pillar
+called the modiolus, the whole cochlea
+forming a rounded cone something like
+the shell of a snail though it is only
+about 5 mm. from base to apex. Projecting
+from the modiolus is a horizontal
+plate which runs round it from base to
+apex like a spiral staircase; this is
+known as the lamina spiralis, and it
+stretches nearly half-way across the canal
+of the cochlea. At the summit it ends
+in a little hook named the hamulus. The
+modiolus is pierced by canals which
+transmit branches of the auditory nerve
+to the lamina spiralis.</p>
+
+<table class="flt" style="float: left; width: 200px;" summary="Illustration">
+<tr><td class="figleft1"><img style="width:146px; height:377px" src="images/img792b.jpg" alt="" /></td></tr>
+<tr><td class="caption1"><span class="sc">Fig. 3.</span>&mdash;<i>cl</i>, Columnar
+cells covering the crista acustica; <i>p</i>, peripheral,
+and <i>c</i>, central processes of auditory
+cells; <i>n</i>, nerve fibres.
+(After Rüdinger.)</td></tr></table>
+
+<p>The membranous labyrinth lies in the
+bony labyrinth, but does not fill it; between
+the two is the fluid called perilymph,
+while inside the membranous
+labyrinth is the endolymph. In the bony
+vestibule lie two membranous bags,
+the saccule (fig. 2, S) in front, and the
+utricle (fig. 2, U) behind; each of these
+has a special patch or macula to which
+twigs of the auditory nerve are supplied, and in the mucous
+membrane of which specialized hair cells are found (fig. 3, <i>p</i>).</p>
+
+<p>Attached to the maculae are crystals of carbonate of lime
+called otoconia. The membranous semicircular canals are very
+much smaller in section than <span class="correction" title="amended from tbe">the</span> bony; in the ampulla of
+each is a ridge, the crista acustica, which is covered by a mucous
+<span class="pagenum"><a name="page793" id="page793"></a>793</span>
+membrane containing sensory hair cells like those in the maculae. All
+the canals open into the utricle. From the lower part of the saccule a
+small canal called the ductus endolymphaticus (fig. 2, <i>dv</i>) runs into the
+aqueductus vestibuli; it is soon joined by a small duct from the
+utricle, and ends, close to the dura mater of the posterior fossa of the
+cranium, as the saccus endolymphaticus, which may have minute
+perforations through which the endolymph can pass. Anteriorly the
+saccule communicates with the membranous cochlea or scala media by a
+short ductus reuniens (fig. 2, <i>dr</i>). A section through each turn of the
+cochlea shows the bony lamina spiralis, already noticed, which is
+continued right across the canal by the basilar membrane (fig. 4, <i>bm</i>),
+thus cutting the canal into an upper and lower half and connected with
+the outer wall by the strong spiral ligament (fig. 4, <i>sl</i>). Near the free
+end of the lamina spiralis another membrane called the membrane of
+Reissner (fig. 4, <i>m</i>R) is attached, and runs outward and upward to the
+outer wall, taking a triangular slice out of the upper half of the
+section. There are now three canals seen in section, the upper of which
+is the scala vestibuli (fig. 4, SV), the middle and outer the scala
+media, ductus cochlearis or true membranous cochlea (fig. 4, DC), while
+the lower is the scala tympani (fig. 4, ST). The scala vestibuli and
+scala tympani communicate at the apex of the cochlea by an opening known
+as the helicotrema, so that the perilymph can here pass from one canal
+to the other. At the base of the cochlea the
+perilymph in the scala vestibuli is continuous with that in the
+vestibule, but that in the scala tympani bathes the inner surface of the
+membrane stretched across the fenestra rotunda, and also communicates
+with the subarachnoid space through the aqueductus cochleae, which opens
+into the posterior cranial fossa. The scala media containing endolymph
+communicates, as has been shown, with the saccule through the canalis
+reuniens, while, at the apex of the cochlea, it ends in a blind
+extremity of considerable morphological interest called the lagena.</p>
+
+<table class="pic" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter" colspan="2"><img style="width:416px; height:486px" src="images/img793a.jpg" alt="" /></td></tr>
+<tr><td class="caption" colspan="2"><span class="sc">Fig.</span> 4.&mdash;Transverse Section through the Tube of the Cochlea.</td></tr>
+
+<tr><td class="f90" style="width: 50%; vertical-align: top;">
+<p><i>m</i>, Modiolus.</p>
+<p>0, Outer wall of cochlea.</p>
+<p>SV, Scala vestibuli.</p>
+<p>ST, Scala tympani.</p>
+<p>DC, Ductus cochlearis.</p>
+<p><i>m</i>R, Membrane of Reissner.</p></td>
+
+<td class="f90" style="width: 50%; vertical-align: top;">
+<p><i>bm</i>, Basilar membrane.</p>
+<p><i>cs</i>, Crista spiralis.</p>
+<p><i>sl</i>, Spiral ligament.</p>
+<p><i>sg</i>, Spiral ganglion of auditory nerve.</p>
+<p><i>oc</i>, Organ of Corti.</p></td></tr></table>
+
+<p>The scala media contains the essential organ of hearing or organ of
+Corti (fig. 4, <i>oc</i>), which lies upon the inner part of the basilar
+membrane; it consists of a tunnel bounded on each side of the inner and
+outer rods of Corti; on each side of these are the inner and outer hair
+cells, between the latter of which are found the supporting cells of
+Deiters. Most externally are the large cells of Hensen. A delicate
+membrane called the lamina reticularis covers the top of all these, and
+is pierced by the hairs of the hair cells, while above this is the loose
+membrana tectoria attached to the periosteum of the lamina spiralis,
+near its tip, internally, and possibly to some of Deiter&rsquo;s cells
+externally. The cochlear branch of the auditory nerve enters the lamina
+spiralis, where a spiral ganglion (fig. 4, <i>sg</i>) is developed on it; after
+this it is distributed to the inner and outer hair cells.</p>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:741px; height:373px" src="images/img793b.jpg" alt="" /></td></tr>
+<tr><td class="tcl f80">(From R. Howden&mdash;Cunningham&rsquo;s <i>Text-Book of Anatomy</i>.)</td></tr>
+<tr><td class="caption"><span class="sc">Fig.</span> 5.&mdash;Transverse Section of Corti&rsquo;s Organ from the Central Coil
+of Cochlea (Retzius).</td></tr></table>
+
+<div class="condensed">
+<p>For further details see <i>Text-Book of Anatomy</i>, edited by D.J. Cunningham
+(Edinburgh, 1906); Quain&rsquo;s <i>Elements of Anatomy</i> (London, 1893); Gray&rsquo;s
+<i>Anatomy</i> (London, 1905); <i>A Treatise on Anatomy</i>, edited by H. Morris
+(London, 1902); <i>A Text-Book of Human Anatomy</i>, by A. Macalister (London,
+1889).</p>
+</div>
+
+<p><i>Embryology.</i>&mdash;The pinna is formed from six tubercles which appear round
+the dorsal end of the hyomandibular cleft or, more strictly speaking,
+pouch. Those for the tragus and anterior part of the helix belong to the
+first or mandibular arch, while those for the antitragus, antihelix and
+lobule come from the second or hyoid arch. The tubercle for the helix is
+dorsal to the end of the cleft where the two arches join. The external
+auditory meatus, tympanum and Eustachian tube are remains of the
+hyomandibular cleft, the membrana tympani being a remnant of the cleft
+membrane and therefore lined by ectoderm outside and entoderm inside.
+The origin of the ossicles is very doubtful. H. Gadow&rsquo;s view, which is
+one of the latest, is that all three are derived from the hyomandibular
+plate which connects the dorsal ends of the hyoid and mandibular bars
+(<i>Anatomischer Anzeiger</i>, Bd. xix., 1901, p. 396). Other papers which
+should be consulted are those of E. Gaupp, <i>Anatom. Hefte, Ergebnisse</i>,
+Bd. 8, 1898, p. 991, and J.A. Hammar, <i>Archiv f. mikr. Anat.</i> lix.,
+1902. These papers will give a clue to the immense literature of the
+subject. The internal ear first appears as a pit from the cephalic
+ectoderm, the mouth of which in Man and other mammals closes up, so that
+a pear-shaped cavity is left. The stalk of the pear which is nearest the
+point of invagination is called the recessus labyrinthi, and this, after
+losing its connexion with the surface of the embryo, grows backward
+toward the posterior cranial fossa and becomes the ductus
+endolymphaticus. The lower part of the vesicle grows forward and becomes
+the cochlea, while from the upper part three hollow circular plates grow
+out, the central parts of which disappear, leaving the margin as the
+semicircular canals. Subsequently constrictions appear in the vesicle
+marking off the saccule and utricle. From the surrounding
+<span class="pagenum"><a name="page794" id="page794"></a>794</span>
+mesoderm the petrous bone is formed by a process of
+chondrification and ossification.</p>
+
+<div class="condensed">
+<p>See W. His, Junr., <i>Archiv f. Anat. und Phys.</i>, 1889, supplement,
+p. 1; also Streeter, <i>Am. Journ. of Anat.</i> vi., 1907.</p>
+</div>
+
+<p><i>Comparative Anatomy.</i>&mdash;The ectodermal inpushing of the
+internal ear has probably a common origin with the organs of
+the lateral line of fish. In the lower forms the ductus endolymphaticus
+retains its communication with the exterior on the
+dorsum of the head, and in some Elasmobranchs the opening is
+wide enough to allow the passage of particles of sand into the
+saccule. It is probable that this duct is the same which, taking
+a different direction and losing its communication with the skin,
+abuts on the posterior cranial fossa of higher forms (see Rudolf
+Krause, &ldquo;Die Entwickelung des Aq. vestibuli seu d. Endelymphaticus,&rdquo;
+<i>Anat. Anzeiger</i>, Bd. xix., 1901, p. 49). In certain
+Teleostean fishes the swim bladder forms a secondary communication
+with the internal ear by means of special ossicles (see G.
+Ridewood, <i>Journ. Anat. &amp; Phys.</i> vol. xxvi.). Among the
+Cyclostomata the external semicircular canals are wanting;
+Petromyzon has the superior and posterior only, while in Myxine
+these two appear to be fused so that only one is seen. In higher
+types the three canals are constant. Concretions of carbonate of
+lime are present in the internal ears of almost all vertebrates;
+when these are very small they are called otoconia, but when, as
+in most of the teleostean fishes, they form huge concretions, they
+are spoken of as otoliths. One shark, Squatina, has sand instead
+of otoconia (C. Stewart, <i>Journ. Linn. Society</i>, xxix. 409). The
+utricle, saccule, semicircular canals, ductus endolymphaticus
+and a short lagena are the only parts of the ear present in
+fish.</p>
+
+<p>The Amphibia have an important sensory area at the base of
+the lagena known as the macula acustica basilaris, which is
+probably the first rudiment of a true cochlea. The ductus
+endolymphaticus has lost its communication with the skin, but
+it is frequently prolonged into the skull and along the spinal
+canal, from which it protrudes, through the intervertebral
+foramina, bulging into the coelom. This is the case in the common
+frog (A. Coggi, <i>Anat. Anz.</i> 5. Jahrg., 1890, p. 177). In this
+class the tympanum and Eustachian tube are first developed;
+the membrana tympani lies flush with the skin of the side of the
+head, and the sound-waves are transmitted from it to the internal
+ear by a single bony rod&mdash;the columella.</p>
+
+<p>In the Reptilia the internal ear passes through a great range
+of development. In the Chelonia and Ophidia the cochlea is as
+rudimentary as in the Amphibia, but in the higher forms
+(Crocodilia) there is a lengthened and slightly twisted cochlea,
+at the end of which the lagena forms a minute terminal appendage.
+At the same time indications of the scalae tympani and
+vestibuli appear. As in the Amphibia the ductus endolymphaticus
+sometimes extends into the cranial cavity and on into other
+parts of the body. Snakes have no tympanic membrane. In the
+birds the cochlea resembles that of the crocodiles, but the posterior
+semicircular canal is above the superior where they join one
+another. In certain lizards and birds (owls) a small fold of skin
+represents the first appearance of an external ear. In the
+monotremes the internal ear is reptilian in its arrangement,
+but above them the mammals always have a spirally twisted
+cochlea, the number of turns varying from one and a half in the
+Cetacea to nearly five in the rodent <i>Coelogenys</i>. The lagena is
+reduced to a mere vestige. The organ of Corti is peculiar to
+mammals, and the single columella of the middle ear is replaced
+by the three ossicles already described in Man (see Alban Doran,
+&ldquo;Morphology of the Mammalian Ossicula auditus,&rdquo; <i>Proc. Linn.
+Soc.</i>, 1876-1877, xiii. 185; also <i>Trans. Linn. Soc.</i> 2nd Ser. Zool.
+i. 371). In some mammals, especially Carnivora, the middle
+ear is enlarged to form the tympanic bulla, but the mastoid cells
+are peculiar to Man.</p>
+
+<div class="condensed">
+<p>For further details see G. Retzius, <i>Das Gehörorgan der Wirbelthiere</i>
+(Stockholm, 1881-1884); Catalogue of the Museum of the R.
+College of Surgeons&mdash;Physiological Series, vol. iii. (London, 1906);
+R. Wiedersheim&rsquo;s <i>Vergleichende Anatomie der Wirbeltiere</i> (Jena,
+1902).</p>
+</div>
+<div class="author">(F. G. P.)</div>
+
+<p class="pt2 center sc">Diseases of the Ear</p>
+
+<p>Modern scientific aural surgery and medicine (commonly
+known as Otology) dates from the time of Sir William Wilde
+of Dublin (1843), whose work marked a great advance in the
+application of anatomical, physiological and therapeutical
+knowledge to the study of this organ. Less noticeable contributions
+to the subject had not long before been made by
+Saunders (1827), Kramer (1833), Pilcher (1841) and Yearsley
+(1841). The next important event in the history of otology
+was the publication of J. Toynbee&rsquo;s book in 1860 containing
+his valuable anatomical and pathological observations. Von
+Tröltsch of Würzburg, following on the lines of Wilde and
+Toynbee, produced two well-known works in 1861 and 1862,
+laying the foundation of the study in Germany. In that country
+and in Austria he was followed by Hermann Schwartze, Politzer,
+Gruber, Weber-Liel, Rüdinger, Moos and numerous others.
+France produced Itard, de la Charrière, Menière, Loewenberg
+and Bonnafont; and Belgium, Charles Delstanche, father and
+son. In Great Britain the work was carried on by James Hinton
+(1874), Peter Allen (1871), Patterson Cassells and Sir William
+Dalby. In America we may count among the early otologists
+Edward H. Clarke (1858), D.B. St John Roosa, H. Knapp,
+Clarence J. Blake, Albert H. Buck and Charles Burnett. Other
+workers all over the world are too numerous to mention.</p>
+
+<p><i>Various Diseases and Injuries.</i>&mdash;Diseases of the ear may affect
+any of the three divisions, the external, middle or internal ear.
+The commoner affections of the <i>auricle</i> are eczema, various
+tumours (simple and malignant), and serous and sebaceous
+cysts. Haematoma auris (othaematoma), or effusion of blood
+into the auricle, is often due to injury, but may occur
+spontaneously, especially in insane persons. The chief diseases
+of the <i>external auditory canal</i> are as follows:&mdash;impacted cerumen
+(or wax), circumscribed (or furuncular) inflammation, diffuse
+inflammation, strictures due to inflammatory affections, bony
+growths, fungi (otomycosis), malignant disease, caries and
+necrosis, and foreign bodies.</p>
+
+<p>Diseases of the <i>middle ear</i> fall into two categories, suppurative
+and non-suppurative (<i>i.e.</i> with and without the formation of pus).
+Suppurative inflammation of the middle ear is either acute or
+chronic, and is in either case accompanied by perforation of the
+drum head and discharge from the ear. The chief importance
+of these affections, in addition to the symptoms of pain, deafness,
+discharge, &amp;c., is the serious complications which may ensue
+from their neglect, viz. aural polypi, caries and necrosis of the
+bone, affections of the mastoid process, including the mastoid
+antrum, paralysis of the facial nerve, and the still more serious
+intracranial and vascular infective diseases, such as abscess in
+the brain (cerebrum or cerebellum), meningitis, with subdural
+and extradural abscesses, septic thrombosis of the sigmoid and
+other venous sinuses, and pyaemia. It is owing to the possibility
+of these complications that life insurance companies usually,
+and rightly, inquire as to the presence of ear discharge before
+accepting a life. Patterson Cassells of Glasgow urged this special
+point as long ago as 1877. Acute suppurative disease of the
+middle ear is often due to the exanthemata, scarlatina, measles
+and smallpox, and to bathing and diving. It may also be caused
+by influenza, diphtheria and pulmonary phthisis.</p>
+
+<p>Non-suppurative disease of the middle ear may be acute or
+chronic. In the acute form the inflammation is less violent than
+in the acute suppurative inflammation, and is rarely accompanied
+by perforation. Chronic non-suppurative inflammation
+may be divided into the moist form, in which the symptoms are
+improved by inflation of the tympanum through the Eustachian
+tube, and the dry form (including sclerosis), which is more intractable
+and in which this procedure has little or no beneficial
+effect. Diseases of the <i>internal ear</i> may be primary or secondary
+to an affection of the tympanum or to intracranial disease.</p>
+
+<p>Injuries to any part of the ear may occur, among the commoner
+being injuries to the auricle, rupture of the drum head (from
+explosions, blows on the ear or the introduction of sharp bodies
+into the ear canal), and injuries from fractured skull. Congenital
+<span class="pagenum"><a name="page795" id="page795"></a>795</span>
+malformations of the ear are most frequently met with in the
+auricle and external canal.</p>
+
+<p><i>Methods of Examination.</i>&mdash;The methods of examining the ear
+are roughly threefold:&mdash;(1) Testing the hearing with watch,
+voice and tuning-fork. The latter is especially used to distinguish
+between disease of the middle ear (conducting apparatus) and
+that of the internal ear (perceptive apparatus). Our knowledge
+of the subject has been brought to its present state by the labours
+of many observers, notably Weber, Rinne, Schwabach, Lucae
+and Gellé. (2) Examination of the canal and drum-head with
+speculum and reflector, introduced by Kramer, Wilde and von
+Tröltsch. (3) Examination of the drum-cavity through the
+Eustachian tube by the various methods of inflation.</p>
+
+<p><i>Symptoms.</i>&mdash;The chief symptoms of ear diseases are deafness,
+noises in the ear (tinnitus aurium), giddiness, pain and discharge.
+Deafness (or other disturbance of hearing) and noises may occur
+from disease in almost any part of the ear. Purulent discharge
+usually comes from the middle ear. Giddiness is more commonly
+associated with affections of the internal ear.</p>
+
+<p><i>Treatment.</i>&mdash;Ear diseases are treated on ordinary surgical and
+medical lines, due regard being had to the anatomical and physiological
+peculiarities of this organ of sense, and especially to its
+close relationship, on the one hand to the nose and naso-pharynx,
+and on the other hand to the cranium and its contents. The chief
+advance in aural surgery in recent years has been in the surgery
+of the mastoid process and antrum. The pioneers of this work
+were H. Schwartze of Halle, and Stacke of Erfurt, who have been
+followed by a host of workers in all parts of the world. This
+development led to increased attention being paid to the intracranial
+complications of suppurative ear disease, in the treatment
+of which great strides have been made in the last few years.</p>
+
+<p><i>Effects of Diseases of the Nose on the Ear.</i>&mdash;The influence of
+diseases of the nose and naso-pharynx on ear diseases was brought
+out by Loewenberg of Paris, Voltolini of Breslau, and especially
+by Wilhelm Meyer of Copenhagen, the discoverer of adenoid
+vegetations of the naso-pharynx (&ldquo;adenoids&rdquo;), who recognized
+the great importance of this disease and gave an inimitable
+account of it in the <i>Trans. of the Royal Medical and Chirurgical
+Society of London</i>, 1870, and the <i>Archiv für Ohrenheilkunde</i>, 1873.
+Adenoid vegetations, which consist of an abnormal enlargement
+of Luschka&rsquo;s tonsil in the vault of the pharynx, frequently give
+rise to ear disease in children, and, if not attended to, lay the
+foundation of nasal and ear troubles in after life. They are often
+associated with enlargement of the faucial tonsils.</p>
+
+<div class="condensed">
+<p><i>Journals.</i>&mdash;In 1864 the <i>Archiv für Ohrenheilkunde</i> was started by
+Politzer and Schwartze, and, in 1867, the <i>Monatsschrift für Ohrenheilkunde</i>
+(a monthly publication) was founded by Voltolini, Gruber,
+Weber-Liel and Rüdinger. Appearing first as the <i>Archives of
+Ophthalmology and Otology</i>, simultaneously in English and German,
+in 1869, the <i>Archives of Otology</i> became a separate publication under
+the editorship of Knapp, Moos and Roosa in 1879. Amongst other
+journals now existing are <i>Annales des maladies de l&rsquo;oreille et du
+larynx</i> (Paris), <i>Journal of Laryngology</i> (London), <i>Centralblatt für
+Ohrenheilkunde</i> (Leipzig), &amp;c.</p>
+
+<p><i>Societies.</i>&mdash;The earliest society formed was the American Otological
+Society (1868), which held annual meetings and published
+yearly transactions. Flourishing societies for the study of otology
+(sometimes combined with laryngology) exist in almost all civilized
+countries, and they usually publish transactions consisting of original
+papers and cases. The Otological Society of the United Kingdom
+was founded in 1900.</p>
+
+<p><i>International Congresses.</i>&mdash;International Otological congresses
+have been held at intervals of about four years at New York, Milan,
+Basel, Brussels, Florence, London and Bordeaux (1904). The proceedings
+of the congresses appear as substantial volumes.</p>
+
+<p><i>Hospitals.</i>&mdash;The earliest record of a public institution for the
+treatment of ear diseases is a Dispensary for Diseases of the Eye
+and Ear in London, started by Saunders and Cooper, which existed
+in 1804; the aural part, however, was soon closed, so that the actual
+oldest institution appears to be the Royal Ear Hospital, London,
+which was founded by Curtis in 1816. Four years later there was
+started the New York Eye and Ear Infirmary. At the present time
+in every large town of Europe and America ear diseases are treated
+either in separate departments of general hospitals or in institutions
+especially devoted to the purpose.</p>
+
+<p>For a history of otology from the earliest times refer to <i>A Practical
+Treatise on the Diseases of the Ear</i>, by D.B. St John Roosa, M.D.,
+LL.D. (6th edition, New York, 1885), and for a general account of
+the present state of otological science to <i>A Text-Book of the Diseases
+of the Ear for Students and Practitioners</i>, by Professor Dr Adam
+Politzer, transl. by Milton J. Ballin, Ph.B., M.D., and Clarence J.
+Heller, M.D. (4th edition, London, 1902).</p>
+</div>
+<div class="author">(E. C. B.*)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARL,<a name="ar29" id="ar29"></a></span> a title and rank of nobility (corresponding to Lat.
+<i>comes</i>; Fr. <i>comte</i>), now the third in order of the British peerage,
+and accordingly intervening between marquess and viscount.
+Earl, however, is the oldest title and rank of English nobles,
+and was the highest until the year 1337, when the Black Prince
+was created duke of Cornwall by Edward III.</p>
+
+<p>The nature of a modern earldom is readily understood, since
+it is a rank and dignity of nobility which, while it confers no
+official power or authority, is inalienable, indivisible, and descends
+in regular succession to all the heirs under the limitation in the
+grant until, on their failure, it becomes extinct.</p>
+
+<p>The title is of Scandinavian origin, and first appears in England
+under Canute as <i>jarl</i>, which was englished as <i>eorl</i>. Like the
+<i>ealdorman</i>, whose place he took, the <i>eorl</i> was a great royal officer,
+who might be set over several counties, but who presided separately
+in the county court of each with the bishop of the diocese.
+Although there were counts in Normandy before the Norman
+Conquest, they differed in character from the English earls,
+and the earl&rsquo;s position appears to have been but slightly modified
+by the Conquest. He was still generally entitled to the &ldquo;third
+penny&rdquo; of the county, but his office tended, under Norman
+influence, to become an hereditary dignity and his sphere was
+restricted by the Conqueror to a single county. The right to
+the &ldquo;third penny&rdquo; is a question of some obscurity, but its
+possession seems to have been deemed the distinctive mark of
+an earl, while the girding with &ldquo;the sword of the county&rdquo;
+formed the essential feature in his creation or investiture, as it
+continued to do for centuries later. The fact that every earl
+was the earl of a particular county has been much obscured
+by the loose usage of early times, when the style adopted was
+sometimes that of the noble&rsquo;s surname (<i>e.g.</i> the Earls Ferrers),
+sometimes that of his chief seat (<i>e.g.</i> the Earls of Arundel), and
+sometimes that of the county. Palatine earldoms, or palatinates,
+were those which possessed <i>regalia</i>, <i>i.e.</i> special privileges delegated
+by the crown. The two great examples, which dated from
+Norman times, were Chester and Durham, where the earl and
+the bishop respectively had their own courts and jurisdiction,
+and were almost petty sovereigns.</p>
+
+<p>The earliest known charter creating an earl is that by which
+Stephen bestowed on Geoffrey de Mandeville, in or about 1140,
+the earldom of Essex as an hereditary dignity. Several other
+creations by Stephen and the empress Maud followed in quick
+succession. From at least the time of the Conquest the earl
+had a double character; he was one of the &ldquo;barons,&rdquo; or tenants
+in chief, in virtue of the fief he held of the crown, as well as an
+earl in virtue of his &ldquo;belting&rdquo; (with the sword) and his &ldquo;third
+penny&rdquo; of the county. His fief would descend to the heirs of
+his body; and the earliest charters creating earldoms were
+granted with the same &ldquo;limitation.&rdquo; The dignity might thus
+descend to a woman, and, in that case, like the territorial fief,
+it would be held by her husband, who might be summoned to
+parliament in right of it. The earldom of Warwick thus passed
+through several families till it was finally obtained, in 1449,
+by the Kingmaker, who had married the heiress of the former
+earls. But in the case of &ldquo;co-heiresses&rdquo; (more daughters than
+one), the king determined which, if any, should inherit the
+dignity.</p>
+
+<p>The 14th century saw some changes introduced. The earldom
+of March, created in 1328, was the first that was not named
+from a county or its capital town. Under Edward III. also an
+idea appears to have arisen that earldoms were connected with
+the tenure of lands, and in 1337 several fresh ones were created
+and large grants of lands made for their support. The first
+earldom granted with limitation to the heirs male of the grantee&rsquo;s
+body was that of Nottingham in 1383. Another innovation
+was the grant of the first earldom for life only in 1377. The
+girding with the sword was the only observance at a creation till
+the first year of Edward VI., when the imposition of the cap
+<span class="pagenum"><a name="page796" id="page796"></a>796</span>
+of dignity and a circlet of gold was added. Under James I. the
+patent of creation was declared to be sufficient without any
+ceremony. An earl&rsquo;s robe of estate has three bars of ermine,
+but possibly it had originally four.</p>
+
+<p>Something should be said of anomalous earldoms with Norman
+or Scottish styles. The Norman styles originated either under
+the Norman kings or at the time of the conquest of Normandy
+by the house of Lancaster. To the former period belonged
+that of Aumale, which successive fresh creations, under the
+Latinized form &ldquo;Albemarle&rdquo; have perpetuated to the present
+day (see <span class="sc"><a href="#artlinks">Albemarle, Earls and Dukes of</a></span>). The so-called
+earls of Eu and of Mortain, in that period, were really holders
+of Norman <i>comtés</i>. Henry V. and his son created five or six,
+it is said, but really seven at least, Norman countships or
+earldoms, of which Harcourt (1418), Perche (1419), Dreux (1427)
+and Mortain (? 1430) were bestowed on English nobles, Eu (1419),
+and Tankerville (1419) on English commoners, and Longueville
+(1419) on a foreigner, Gaston de Foix. Of these the earldom of
+&ldquo;Eu&rdquo; was assumed by the earls of Essex till the death of Robert,
+the parliament&rsquo;s general (1646), while the title of Tankerville
+still survives under a modern creation (1714). An anomalous
+royal licence of 1661 permitted the earl of Bath to use the title of
+earl of Corbeil by alleged hereditary right. Of Scottish earldoms
+recognized in the English parliament the most remarkable case is
+that of the Lords Umfraville, who were summoned for three generations
+(1297-1380), as earls of Angus; Henry, Lord Beaumont,
+also was summoned as earl of Buchan from 1334 to 1339.</p>
+
+<p>The earldom of Chester is granted to the princes of Wales on
+their creation, and the Scottish earldom of Carrick is held by
+the eldest son of the sovereign under act of parliament.</p>
+
+<p>The premier earldom is that of Arundel (<i>q.v.</i>), but as this
+is at present united with the dukedom of Norfolk, the oldest
+earldom not merged in a higher title is that of Shrewsbury (1442),
+the next in seniority being Derby (1485), and Huntingdon (1529).
+These three have been known as &ldquo;the catskin earls,&rdquo; a term of
+uncertain origin. The ancient earldom of Wiltshire (1397) was
+unsuccessfully claimed in 1869 by Mr Scrope of Danby, and that
+of Norfolk (1312), in 1906, by Lord Mowbray and Stourton.</p>
+
+<p>The premier earldom of Scotland as recognized by the Union
+Roll (1707), is that of Crawford, held by the Lindsays since its
+creation in 1398; but it is not one of the ancient &ldquo;seven earldoms.&rdquo;
+The Decreet of Ranking (1606) appears to have recognized
+the earldom of Sutherland as the most ancient in virtue
+of a charter of 1347, but the House of Lords&rsquo; decision of 1771
+recognized it as having descended from at least the year 1275,
+and it may be as old as 1228. It is at present united with the
+dukedom of Sutherland. The original &ldquo;seven earldoms&rdquo; (of
+which it was one) represented seven provinces, each of which
+was under a &ldquo;<i>mormaer</i>.&rdquo; This Celtic title was rendered &ldquo;<i>jarl</i>&rdquo;
+by the Norsemen, and under Alexander I. (<i>c.</i> 1115) began to be
+replaced by earl (<i>comes</i>), owing to Anglo-Norman influence,
+which also tended to make these earldoms less official and more
+feudal.</p>
+
+<p>In Ireland the duke of Leinster is, as earl of Kildare, premier
+earl as well as premier duke.</p>
+
+<p>An earl is &ldquo;Right Honourable,&rdquo; and is styled &ldquo;My Lord.&rdquo;
+His eldest son bears his father&rsquo;s &ldquo;second title,&rdquo; and therefore,
+that second title being in most cases a viscounty, he generally
+is styled &ldquo;Viscount&rdquo;; where, as with Devon and Huntingdon,
+there is no second title, one may be assumed for convenience;
+under all circumstances, however, the eldest son of an earl takes
+precedence immediately after the viscounts. The younger sons
+of earls are &ldquo;Honourable,&rdquo; but all their daughters are &ldquo;Ladies.&rdquo;
+In formal documents and instruments, the sovereign, when
+addressing or making mention of any peer of the degree of an
+earl, usually designates him &ldquo;trusty and well-beloved cousin,&rdquo;&mdash;a
+form of appellation first adopted by Henry IV., who either
+by descent or alliance was actually related to every earl and
+duke in the realm. The wife of an earl is a countess; she is
+&ldquo;Right Honourable,&rdquo; and is styled &ldquo;My Lady.&rdquo; For the earl&rsquo;s
+coronet see <span class="sc"><a href="#artlinks">Crown and Coronet</a></span>.</p>
+
+<div class="condensed">
+<p>See Lord&rsquo;s <i>Reports on the Dignity of a Peer</i>; Pike&rsquo;s <i>Constitutional</i>
+<i>History of the House of Lords</i>; Selden&rsquo;s <i>Titles of Honour</i>; G.E.
+C(okayne)&rsquo;s <i>Complete Peerage</i>; Round&rsquo;s <i>Geoffrey de Mandeville</i>.</p>
+</div>
+<div class="author">(J. H. R.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARLE, JOHN<a name="ar30" id="ar30"></a></span> (<i>c.</i> 1601-1665), English divine, was born at
+York about 1601. He matriculated at Christ Church, Oxford,
+but migrated to Merton, where he obtained a fellowship. In
+1631 he was proctor and also chaplain to Philip, earl of Pembroke,
+then chancellor of the university, who presented him to the
+rectory of Bishopston in Wiltshire. His fame spread, and in
+1641 he was appointed chaplain and tutor to Prince Charles.
+In 1643 he was elected one of the Assembly of Divines at Westminster,
+but his sympathies with the king and with the Anglican
+Church were so strong that he declined to sit. Early in 1643 he
+was chosen chancellor of the cathedral of Salisbury, but of this
+preferment he was soon deprived as a &ldquo;malignant.&rdquo; After
+Cromwell&rsquo;s great victory at Worcester, Earle went abroad, and
+was named clerk of the closet and chaplain to Charles II. He
+spent a year at Antwerp in the house of Isaac Walton&rsquo;s friend,
+George Morley, who afterwards became bishop of Winchester.
+He next joined the duke of York (James II.) at Paris, returning
+to England at the Restoration. He was at once appointed dean
+of Westminster, and in 1661 was one of the commissioners for
+revising the liturgy. He was on friendly terms with Richard
+Baxter. In November 1662 he was consecrated bishop of
+Worcester, and was translated, ten months later, to the see of
+Salisbury, where he conciliated the nonconformists. He was
+strongly opposed to the Conventicle and Five Mile Acts. During
+the great plague Earle attended the king and queen at Oxford,
+and there he died on the 17th of November 1665.</p>
+
+<p>Earle&rsquo;s chief title to remembrance is his witty and humorous
+work entitled <i>Microcosmographie, or a Peece of the World discovered,
+in Essayes and Characters</i>, which throws light on the
+manners of the time. First published anonymously in 1628,
+it became very popular, and ran through ten editions in the
+lifetime of the author. The style is quaint and epigrammatic;
+and the reader is frequently reminded of Thomas Fuller by such
+passages as this: &ldquo;A university dunner is a gentlemen follower
+cheaply purchased, for his own money has hyr&rsquo;d him.&rdquo; Several
+reprints of the book have been issued since the author&rsquo;s death;
+and in 1671 a French translation by J. Dymock appeared with
+the title of <i>Le Vice ridiculé</i>. Earle was employed by Charles II.
+to make the Latin translation of the <i>Eikon Basilike</i>, published
+in 1649. A similar translation of R. Hooker&rsquo;s <i>Ecclesiastical
+Polity</i> was accidentally destroyed.</p>
+
+<p>&ldquo;Dr Earle,&rdquo; says Lord Clarendon in his <i>Life</i>, &ldquo;was a man of
+great piety and devotion, a most eloquent and powerful preacher,
+and of a conversation so pleasant and delightful, so very innocent,
+and so very facetious, that no man&rsquo;s company was more desired
+and loved. No man was more negligent in his dress and habit
+and mien, no man more wary and cultivated in his behaviour
+and discourse. He was very dear to the Lord Falkland, with
+whom he spent as much time as he could make his own.&rdquo;</p>
+
+<div class="condensed">
+<p>See especially Philip Bliss&rsquo;s edition of the <i>Microcosmographie</i>
+(London, 1811), and E. Arber&rsquo;s Reprint (London, 1868).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARLE, RALPH<a name="ar31" id="ar31"></a></span> (1751-1801), American historical and portrait
+painter, was born at Leicester, Massachusetts, on the 11th
+of May 1751. Like so many of the colonial craftsmen, Earle
+was self-taught, and for many years was an itinerant painter.
+He went with the Governor&rsquo;s Guard to Lexington and made
+battle sketches, from which in 1775 he painted four scenes,
+engraved by Amos Doolittle, which are probably the first historical
+paintings by an American. After the War of Independence,
+Earle went to London, entered the studio of Benjamin
+West, and painted the king and many notables. After his return
+to America in 1786 he made portraits of Timothy Dwight,
+Governor Caleb Strong, Roger Sherman, and other prominent
+men. He also painted a large picture of Niagara Falls. He
+died at Bolton, Connecticut, on the 16th of August 1801.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARL MARSHAL,<a name="ar32" id="ar32"></a></span> in England, a functionary who ranks as
+the eighth of the great officers of state. He is the head of the
+college of arms, and has the appointment of the kings-of-arms,
+heralds and pursuivants at his discretion. He attends the
+sovereign in opening and closing the session of parliament,
+<span class="pagenum"><a name="page797" id="page797"></a>797</span>
+walking opposite to the lord great chamberlain on his or her
+right hand. It is his duty to make arrangements for the order
+of all state processions and ceremonials, especially for coronations
+and royal marriages and funerals. Like the lord high constable
+he rode into Westminster Hall with the champion after a coronation,
+till the coronation banquet was abandoned, taking
+his place on the left hand, and with the lord great chamberlain
+he assists at the introduction of all newly-created peers into the
+House of Lords.</p>
+
+<p>The marshal appears in the feudal armies to have been in
+command of the cavalry under the constable, and to have in
+some measure superseded him as master of the horse in the
+royal palace. He exercised joint and co-ordinate jurisdiction
+with the constable in the court of chivalry, and afterwards
+became the sole judge of that tribunal till its obsolescence.
+The marshalship of England was formerly believed to have been
+inherited from the Clares by the Marshal family, who had only
+been marshals of the household. It was held, however, by the
+latter family, as the office of chief (<i>magister</i>) marshal, as early
+as the days of Henry I. Through them, under Henry III., it
+passed to the Bigods, as their eldest co-heirs. In 1306 it fell to
+the crown on the death of the last Bigod, earl of Norfolk, who had
+made Edward I. his heir, and in 1316 it was granted by Edward II.
+to his own younger brother, Thomas &ldquo;of Brotherton,&rdquo; earl of
+Norfolk. As yet the style of the office was only &ldquo;marshal&rdquo;
+although the last Bigod holder, being an earl, was sometimes
+loosely spoken of as the earl marshal. The office, having reverted
+to the crown, was granted out anew by Richard II., in 1385, to
+Thomas Mowbray, earl of Nottingham, the representative of
+Thomas &ldquo;of Brotherton.&rdquo; In 1386 the style of &ldquo;earl marshal&rdquo;
+was formally granted to him in addition. After several attainders
+and partial restorations in the reigns of the Tudors and the
+Stuarts, the earl marshalship was granted anew to the Howards
+by Charles II. in 1672 and entailed on their male line, with many
+specific remainders and limitations, under which settlement
+it has regularly descended to the present duke of Norfolk.
+Its holders, however, could not execute the office until the Roman
+Catholic emancipation, and had to appoint deputies. The duke
+is styled earl marshal &ldquo;and hereditary marshal of England,&rdquo; but
+the double style would seem to be an error, though the Mowbrays,
+with their double creation (1385, 1386) might have claimed
+it. His Grace appends the letters &ldquo;E.M.&rdquo; to his signature,
+and bears behind his shield two batons crossed in saltire, the
+marshal&rsquo;s rod (<i>virga</i>) having been the badge of the office from
+Norman times. There appear to have been hereditary marshals
+of Ireland, but their history is not well ascertained. The Keiths
+were Great Marischals of Scotland from at least the days of
+Robert Bruce, and were created earls marischal in or about
+1458, but lost both earldom and office by the attainder of George,
+the 10th earl, in 1716. (See also <span class="sc"><a href="#artlinks">Marshal</a></span>; <span class="sc"><a href="#artlinks">State, Great
+Officers of</a></span>.)</p>
+
+<div class="condensed">
+<p>See &ldquo;The Marshalship of England,&rdquo; in J.H. Round, <i>Commune
+of London and Other Studies</i> (London, 1899); G.E. C(okayne)&rsquo;s
+<i>Complete Peerage</i>.</p>
+</div>
+<div class="author">(J. H. R.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARLOM, RICHARD<a name="ar33" id="ar33"></a></span> (1742-1822), English mezzotint engraver,
+was born and died in London. His natural faculty for art
+appears to have been first called into exercise by admiration for
+the lord mayor&rsquo;s state coach, just decorated by Cipriani. He tried
+to copy the paintings, and was sent to study under Cipriani. He
+displayed great skill as a draughtsman, and at the same time
+acquired without assistance the art of engraving in mezzotint.
+In 1765 he was employed by Alderman Boydell, then one of the
+most liberal promoters of the fine arts, to make a series of drawings
+from the pictures at Houghton Hall; and these he afterwards
+engraved in mezzotint. His most perfect works as engraver are
+perhaps the fruit and flower pieces after the Dutch artists Van
+Os and Van Huysum. Amongst his historical and figure subjects
+are&mdash;&ldquo;Agrippina,&rdquo; after West; &ldquo;Love in Bondage,&rdquo; after
+Guido Reni; the &ldquo;Royal Academy,&rdquo; the &ldquo;Embassy of Hyderbeck
+to meet Lord Cornwallis,&rdquo; and a &ldquo;Tiger Hunt,&rdquo; the last
+three after Zoffany; and &ldquo;Lord Heathfield,&rdquo; after Sir Joshua
+Reynolds. Earlom also executed a series of 200 facsimiles of
+the drawings and sketches of Claude Lorraine, which was
+published in 3 vols. folio, under the title of <i>Liber veritatis</i>
+(1777-1819).</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARLSTON<a name="ar34" id="ar34"></a></span> (formerly <span class="sc">Ercildoune</span>, of which it is a corruption),
+a parish and market town of Berwickshire, Scotland. Pop.
+(1901) 1049. It is situated on Leader Water in Lauderdale,
+72½ m. S.E. of Edinburgh by the North British railway branch
+line from Reston Junction to St Boswells, and about 4 m. N.E.
+of Melrose. When the place was a hamlet of rude huts it was
+called Arcioldun or &ldquo;Prospect Fort,&rdquo; with reference to Black
+Hill (1003 ft.), on the top of which may yet be traced the concentric
+rings of the British fort by which it was crowned. It is
+said to be possible to make out the remains of the cave-dwellings
+of the Ottadeni, the aborigines of the district. In the 12th and
+13th centuries the Lindsays and the earls of March and Dunbar
+were the chief baronial families. The particular link with the
+remote past, however, is the ivy-clad ruin of the ancient tower,
+&ldquo;The Rhymer&rsquo;s Castle,&rdquo; the traditional residence of Thomas
+Learmont, commonly called Thomas of Ercildoune, or Thomas
+the Rhymer, poet and prophet, and friend of the Fairies, who
+was born here about 1225. Rhymer&rsquo;s Tower was crumbling to
+pieces, and its stones were being used in the erection of dykes,
+cottages and houses, when the Edinburgh Border Counties
+Association acquired the relic and surrounding lands in 1895,
+and took steps to prevent further spoliation and decay. The
+leading manufactures are ginghams, tweeds and shirtings, and
+the town is also an important agricultural centre, stock sales
+taking place at regular intervals and cattle and horse fairs being
+held every year. Some 3 m. away is the estate of Bemersyde,
+said to have been in the possession of the Haigs for nearly 1000
+years. The prospect from Bemersyde Hill was Sir Walter
+Scott&rsquo;s favourite view. The castle at Bemersyde was erected
+in 1535 to secure the peace of the Border.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARLY, JUBAL ANDERSON<a name="ar35" id="ar35"></a></span> (1816-1894), American soldier
+and lawyer, was born in Franklin county, Virginia, on the 3rd
+of November 1816, and graduated at the U.S. Military Academy
+in 1837. He served in the Seminole War of 1837-38, after which
+he resigned in order to practise law in Franklin county, Va.
+He also engaged in state politics, and served in the Mexican War
+as a major of Virginia volunteers. He was strongly opposed to
+secession, but thought it his duty to conform to the action of his
+state. As a colonel in the Confederate army, he rendered conspicuous
+service at the first battle of Bull Run (<i>q.v.</i>). Promoted
+brigadier-general, and subsequently major-general, Early served
+throughout the Virginian campaigns of 1862-63, and defended
+the lines of Fredericksburg during the battle of Chancellorsville.
+At Gettysburg he commanded his division of Ewell&rsquo;s corps.
+In the campaign of 1864 Early, who had now reached the rank
+of lieutenant-general, commanded the Confederate forces in the
+Shenandoah Valley. The action of Lynchburg left him free to
+move northwards, his opponent being compelled to march away
+from the Valley. Early promptly utilized his advantage, crossed
+the Potomac, and defeated, on the Monocacy, all the troops
+which could be gathered to meet him. He appeared before the
+lines of Washington, put part of Maryland and Pennsylvania
+under contribution, and only retired to the Valley when
+threatened by heavy forces hurriedly sent up to Washington.
+He then fought a successful action at Winchester, reappeared
+on the Potomac, and sent his cavalry on a raid into
+Pennsylvania. A greatly superior army was now formed under
+General Sheridan to oppose Early. In spite of his skill and energy
+the Confederate leader was defeated in the battles of Winchester
+and Fisher&rsquo;s Hill. Finally, on the 19th of October, after inflicting
+at first a severe blow upon the Federal army in its camps
+on Cedar Creek, he was decisively beaten by Sheridan. (See
+<span class="sc"><a href="#artlinks">Shenandoah Valley Campaigns</a></span>.) Waynesboro (March 1865)
+was his last fight, after which he was relieved from his command.
+General Early was regarded by many as the ablest soldier, after
+Lee and Jackson, in the Army of Northern Virginia, and one of
+the ablest in the whole Confederate army. That he failed to make
+headway against an army far superior in numbers, and led by a
+general of the calibre of Sheridan, cannot be held to prove the
+<span class="pagenum"><a name="page798" id="page798"></a>798</span>
+falsity of this judgment. After the peace he went to Canada, but
+in 1867 returned to resume the practice of law. For a time he
+managed in conjunction with General Beauregard the Louisiana
+lottery. He died at Lynchburg, Va., on the 2nd of March 1894.
+General Early was for a time president of the Southern Historical
+Society, and wrote, besides various essays and historical papers,
+<i>A Memoir of the Last Year of the War, &amp;c.</i> (1867).</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARLY ENGLISH PERIOD,<a name="ar36" id="ar36"></a></span> in architecture, the term given
+by Rickman to the first pointed or Gothic style in England,
+nominally 1189-1307, which succeeded the Romanesque or
+Norman period towards the end of the 12th century, and
+developed into the Decorated period in the commencement of
+the 14th century. It is chiefly characterized by the almost
+universal employment of the pointed arch, not only in arches of
+wide span such as those of the nave arcade, but for doorways
+and windows. The actual introduction of the pointed arch took
+place at a much earlier date, as in the nave arcade of the Cistercian
+Abbey of Buildwas (1140), though the clerestory window
+above has semicircular arches. It is customary, therefore, to
+make allowance for a transitional epoch from the middle of the
+12th century. Although the pointed arches used are sometimes
+equilateral and sometimes drop-arches, the lancet-arch is the
+most characteristic. The period is best recognized in England by
+the great depth given to the hollows of the mouldings, alternating
+with fillets and rolls, by the decoration of the hollows with
+the dog-tooth ornament, by the circular abacus of the capitals,
+and the employment of slender detached shafts of Purbeck
+marble which are attached to piers by circular moulded shaft-rings
+(Fr. <i>anneau</i>).</p>
+
+<p>The arches are sometimes cusped; circles with trefoils,
+quatrefoils, &amp;c., are introduced into the tracery, and large rose
+windows in the transept or nave, as at Lincoln (1220). The
+conventional foliage decorating the capitals is of great beauty and
+variety, and extends to spandrils, bosses, &amp;c. In the spandrils
+of the arches of the nave, transept or choir arcades, diaper work
+is occasionally found, as in the transept of Westminster Abbey.
+The latter is one of the chief examples of the period, to which
+must be added the cathedral of Salisbury (except the tower);
+the Galilee at Ely; nave and transept of Wells (1225-1240);
+nave of Lincoln; west front of Peterborough; and the minster
+at Beverley.</p>
+<div class="author">(R. P. S.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARN,<a name="ar37" id="ar37"></a></span> the name of a loch and river in Perthshire, Scotland.
+The loch, lying almost due east and west, is 6½ m. long and
+<span class="spp">4</span>&frasl;<span class="suu">5</span> m. in maximum breadth, 287 ft. deep, with a mean depth of
+138 ft., covers an area of nearly 4 sq. m., has a drainage basin of
+over 54½ sq. m., and stands 317 ft. above the sea. Its waters are
+said never to freeze. It discharges by the river Earn. The points
+of interest on its shores are Lochearnhead (at the southern
+extremity of Glen Ogle), which has a station on the Callander-Oban
+railway, and the ruins of St Blane&rsquo;s chapel; Edinample
+Castle, an old turreted mansion belonging to the marquess of
+Breadalbane, situated in well-wooded grounds near the pretty
+falls of the Ample; Ardvorlich House, the original of Darlinvarach
+in Scott&rsquo;s <i>Legend of Montrose</i>, and the village of St
+Fillans at the foot of the loch, once the terminus of the branch
+of the Caledonian railway from Perth. The river flows out of
+Loch Earn, pursues an eastward course with a gentle inclination
+towards the south, and reaches the Firth of Tay, 6½ m. below
+Perth, after a total run of 49 m. Its chief tributaries on the right
+are the Ruchil, Machany, Ruthven, May and Farg, and on the
+left, the Lednock and Turret. It is navigable by vessels of 50
+tons as far up as Bridge of Earn, and is a notable fishing stream,
+abounding with salmon and trout, perch and pike being also
+plentiful. On the Lednock are the falls of the Devil&rsquo;s Cauldron
+and on the Turret and its feeders several graceful cascades. The
+principal places of interest on the banks of the Earn are Dunira,
+the favourite seat of Henry Dundas, 1st Viscount Melville, who
+took the title of his barony from the estate and to whose memory
+an obelisk was raised on the adjoining hill of Dunmore; the
+village of Comrie; the town of Crieff; the ruined castle of
+Innerpeffray, founded in 1610 by the 1st Lord Maderty, close
+to which is the library founded in 1691 by the 3rd Lord Maderty,
+containing some rare black-letter books and the Bible that belonged
+to the marquess of Montrose; Gascon Hall, now in ruins,
+but with traditions reaching back to the days of Wallace;
+Dupplin Castle, a fine Tudor mansion, seat of the earl of Kinnoull,
+who derives from it the title of his viscounty; Aberdalgie,
+Forgandenny and Bridge of Earn, a health resort situated
+amidst picturesque surroundings. Strathearn, as the valley of
+the Earn is called, extending from the loch to the Firth of Tay,
+is a beautiful and, on the whole, fertile tract, though liable at
+times to heavy floods. The earl of Perth is hereditary steward
+of Strathearn.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARNEST<a name="ar38" id="ar38"></a></span> (probably a corruption of the obsolete <i>arles</i> or <i>erles</i>,
+adapted from Lat. equivalent <i>arrha</i>, due to a confusion with the
+adjective &ldquo;earnest,&rdquo; serious, O. Eng. <i>eornust</i>, cognate with Ger.
+<i>ernst</i>), the payment of a sum of money by the buyer of goods to
+the seller on the conclusion of a bargain as a pledge for its due
+performance. It is almost similar to the <i>arrha</i> of the Roman law,
+which may be traced back in the history of legal institutions to
+a period when the validity of a contract depended not so much
+upon the real intention of the parties, as upon the due observance
+of a prescribed ceremony. But <i>earnest</i> was never part payment,
+which <i>arrha</i> might have been. Apart from its survival as a
+custom, its chief importance in English law is its recognition by
+the Statute of Frauds as giving validity to contracts for the sale
+of goods of a value exceeding £10 (see <span class="sc"><a href="#artlinks">Sale of Goods</a></span>). It is
+in that statute clearly distinguished from part payment, consequently
+any sum, however small, would be sufficient as earnest,
+being given as a token that the contract is binding and should
+be expressly stated so by the giver. The giving of earnest,
+or <i>hand-money</i>, as it is sometimes called, has now fallen into very
+general disuse.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAR-RING,<a name="ar39" id="ar39"></a></span> an ornament worn pendent from the ear, and
+generally suspended (especially among the more civilized races)
+by means of a ring or hook passing through the pendulous
+lobe of the ear. Among savage races the impulse to decorate,
+or at any rate to modify the appearance of the ear, is almost
+universal. With such peoples the ear appendage is chiefly
+remarkable for its extravagant dimensions. Many examples
+may be seen in the ethnographic galleries of the British Museum.
+The Berawan people of Borneo use plugs through the lobe of the
+ear 3¾ in. in diameter. More extraordinary still is an example
+of a stone ear-plug worn by a Masai, 4½ in. in diameter and
+weighing 2 &#8468; 14 oz. (<i>Man</i>, 1905, p. 22). It is stated that
+according to the Masai standard of fashion, the lobes of the ears
+should be enlarged so as to be capable of meeting above the head.
+Among the superior races, though ear ornaments of extravagant
+size and elaboration are not unknown, moderation in size is commonly
+observed, and greater attention is paid to workmanship
+and fineness of material.</p>
+
+<table class="flt" style="float: right; width: 220px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:103px; height:303px" src="images/img799a.jpg" alt="" /></td></tr>
+<tr><td class="caption1 f80">From <i>La Grande Encyclopédie</i>.</td></tr>
+<tr><td class="caption1"><span class="sc">Fig. 1.</span>&mdash;Ear-ring
+from an Assyrian bas
+relief.</td></tr>
+
+<tr><td class="figright1"><img style="width:170px; height:354px" src="images/img799b.jpg" alt="" /></td></tr>
+<tr><td class="caption1 f80">From <i>La Grande Encyclopédie</i>.</td></tr>
+<tr><td class="caption1"><span class="sc">Fig. 2.</span>&mdash;Thetis crossing
+the sea, with the
+armour of Achilles.
+Ear-ring from the
+Crimea, Hermitage
+museum.</td></tr></table>
+
+<p>The general usage appears to have been to have ear-rings
+worn in pairs, the two ornaments in all respects resembling each
+other; in ancient times, or more recently among Oriental races,
+a single ear-ring has sometimes been worn. The use of this kind
+of ornament, which constantly was of great value, dates from the
+remotest historical antiquity, the earliest mention of ear-rings
+occurring in the book of Genesis. It appears probable that the
+ear-rings of Jacob&rsquo;s family, which he buried with his strange idols
+at Bethel, were regarded as amulets or talismans, such unquestionably
+being the estimation in which some ornaments of this class
+have been held from a very early period, as they still are held in
+the East. Thus in New Zealand ear-rings are decorated with the
+teeth of enemies, and with talismanic sharks&rsquo; teeth. Among
+all the Oriental races of whom we have any accurate knowledge,
+the Hebrews and Egyptians excepted, ear-rings always have been
+in general use by both sexes; while in the West, as well as by
+the Hebrews and Egyptians, as a general rule they have been
+considered exclusively female ornaments. By the Greeks and
+Romans also ear-rings were worn only by women, and the wearing
+of them by a man is often spoken of as distinctively oriental.</p>
+
+<p>In archaic art, ear-rings are frequently represented or their
+traces are left in the perforated ear lobes of early statues. After
+the 4th century such perforations occur seldom. In one instance,
+<span class="pagenum"><a name="page799" id="page799"></a>799</span>
+a Greek inscription records the weight of the detachable gold ornaments
+on a statue, among which a pair of ear-rings is included.
+Ear-rings of characteristic form are frequently discovered by
+excavation. In Egypt, a system of pendent
+chains is found hanging from a disk. In
+Assyria the decoration consists of pendants
+or knobs attached to a rigid ring. In
+the early civilization represented by Dr
+Schliemann&rsquo;s Trojan investigations, pieces
+of gold plate are suspended by parallel
+chains. In the Mycenaean period, ear-rings
+are infrequent in Greece, but have been
+found in abundance in the Mycenaean finds
+of Enkomi (Cyprus) in the form of pendent
+bulls&rsquo;-heads, or of decorative forms based on
+the bull&rsquo;s head. In the tombs of the Greek
+settlers in the Crimea (4th century <span class="scs">B.C.</span>),
+ear-rings are found of marvellous complexity
+and beauty. The lexicographer Pollux,
+speaking of the names given to ear-rings,
+derived from their forms, mentions caryatids,
+hippocamps and centauresses. Jewels
+of the same class, of exquisite beauty and
+of workmanship that is truly wonderful, have been rescued
+from the sepulchres of ancient Etruria. Ear-rings of comparatively
+simple forms, but set with pearls
+and other stones, were the mode in
+Rome. In some instances, the stones
+were of fabulous value. During the
+Byzantine period they once more attained
+an extravagant size. Researches among
+the burial places of Anglo-Saxon Britain
+have led to the discovery of jewels in considerable
+numbers, which among their
+varieties include ear-rings executed in a
+style that proves the Anglo-Saxons to
+have made no inconsiderable advances
+in the arts of civilization.</p>
+
+<p>These same ornaments, which never
+have fallen into disuse, enjoy at the
+present day a considerable degree of
+favour, and the tide of fashion has set
+towards their increased use. Like all
+other modern jewels, however, the ear-rings
+of our own times as works of art
+can claim no historical attributes, because
+they consist as well of reproductions from
+all past ages and of every race as of
+fanciful productions that certainly can
+be assigned to no style of art whatever.
+As one of the curiosities of the subject it may be mentioned
+that Antonia, wife of Drusus, is said by Pliny to have attached
+a pair of ear-rings to her pet lamprey.</p>
+
+
+<hr class="art" style="clear: both;" />
+<p><span class="bold">EARTH<a name="ar40" id="ar40"></a></span> (a word common to Teutonic languages, cf. Ger. <i>Erde</i>,
+Dutch <i>aarde</i>, Swed. and Dan. <i>jord</i>; outside Teutonic it appears
+only in the Gr. <span class="grk" title="eraze">&#7956;&#961;&#945;&#950;&#949;</span>, on the ground; it has been connected
+by some etymologists with the Aryan root <i>ar-</i>, to plough, which
+is seen in the Lat. <i>arare</i>, obsolete Eng. &ldquo;ear,&rdquo; and Gr. <span class="grk" title="aroun">&#7936;&#961;&#959;&#8166;&#957;</span>, but
+this is now considered very doubtful; see G. Curtius, <i>Greek
+Etymology</i>, Eng. trans., i. 426; Max Müller, <i>Lectures</i>, 8th ed.
+i. 294). From early times the word &ldquo;earth&rdquo; has been used
+in several connexions&mdash;from that of soil or ground to that
+of the planet which we inhabit, but it is difficult to trace
+the exact historic sequence of the diverse usages. In the
+cosmogony of the Pythagoreans, Platonists and other philosophers,
+the term or its equivalent denoted an element or
+fundamental quality which conferred upon matter the character
+of earthiness; and in the subsequent development of theories
+as to the ultimate composition of matter by the alchemists,
+iatrochemists, and early phlogistonists an element of the same
+name was retained (see <span class="sc"><a href="#artlinks">Element</a></span>). In modern chemistry, the
+common term &ldquo;earth&rdquo; is applied to certain oxides:&mdash;the
+&rdquo;alkaline earths&rdquo; (<i>q.v.</i>) are the oxides of calcium (lime), barium
+(baryta) and strontium (strontia); the &rdquo;rare earths&rdquo; (<i>q.v.</i>) are
+the oxides of a certain class of rare metals.</p>
+
+<p class="pt2 center sc">The Earth</p>
+
+<p>The terrestrial globe is a member of the Solar system, the third
+in distance from the Sun, and the largest within the orbit of
+Jupiter. In the wider sense it may be regarded as composed
+of a gaseous atmosphere (see <span class="sc"><a href="#artlinks">Meteorology</a></span>), which encircles
+the crust or lithosphere (see <span class="sc"><a href="#artlinks">Geography</a></span>), and surface waters
+or hydrosphere (see <span class="sc"><a href="#artlinks">Ocean and Oceanography</a></span>). The description
+of the surface features is a branch of Geography, and the
+discussions as to their origin and permanence belongs to Physiography
+(in the narrower sense), physiographical geology, or
+physical geography. The investigation of the crust belongs
+to geology and of rocks in particular to petrology.</p>
+
+<p>In the present article we shall treat the subject matter of the
+Earth as a planet under the following headings:&mdash;(1) Figure
+and Size, (2) Mass and Density, (3) Astronomical Relations,
+(4) Evolution and Age. These subjects will be treated summarily,
+readers being referred to the article <span class="sc"><a href="#artlinks">Astronomy</a></span> and to the
+cross-references for details.</p>
+
+<p>1. <i>Figure and Size.</i>&mdash;To primitive man the Earth was a flat
+disk with its surface diversified by mountains, rivers and seas.
+In many cosmogonies this disk was encircled by waters, unmeasurable
+by man and extending to a junction with the sky;
+and the disk stood as an island rising up through the waters from
+the floor of the universe, or was borne as an immovable ship on
+the surface. Of such a nature was the cosmogony of the Babylonians
+and Hebrews; Homer states the same idea, naming
+the encircling waters <span class="grk" title="Ôkeanos">&#8040;&#954;&#949;&#945;&#957;&#972;&#962;</span>; and Hesiod regarded it as a
+disk midway between the sky and the infernal regions. The
+theory that the Earth extended downwards to the limit of the
+universe was subjected to modification when it was seen that the
+same sun and stars reappeared in the east after their setting in
+the west. But man slowly realized that the earth was isolated
+in space, floating freely as a balloon, and much speculation was
+associated about that which supported the Earth. Tunnels
+in the foundations to permit the passage of the sun and stars
+were suggested; the Greeks considered twelve columns to
+support the heavens, and in their mythology the god Atlas
+appears condemned to support the columns; while the Egyptians
+had the Earth supported by four elephants, which themselves
+stood on a tortoise swimming on a sea. Earthquakes were
+regarded as due to a movement of these foundations; in Japan
+this was considered to be due to the motion of a great spider,
+an animal subsequently replaced by a cat-fish; in Mongolia
+it is a hog; in India, a mole; in some parts of South America,
+a whale; and among some of the North American Indians,
+a giant tortoise.</p>
+
+<p>The doctrine of the spherical form has been erroneously
+assigned to Thales; but he accepted the Semitic conception of the
+disk, and regarded the production of springs after earthquakes
+as due to the inrushing of the waters under the Earth into fissures
+in the surface. His pupil, Anaximander (610-547), according
+to Diogenes Laërtius, believed it to be spherical (see <i>The
+Observatory</i>, 1894, P. 208); and Anaximenes probably held a
+similar view. The spherical form is undoubtedly a discovery
+of Pythagoras, and was taught by the Pythagoreans and by the
+Eleatic Parmenides. The expositor of greatest moment was
+Aristotle; his arguments are those which we employ to-day:&mdash;the
+ship gradually disappearing from hull to mast as it recedes
+from the harbour to the horizon; the circular shadow cast by the
+Earth on the Moon during an eclipse, and the alteration in the
+appearance of the heavens as one passes from point to point on
+the Earth&rsquo;s surface.<a name="fa1b" id="fa1b" href="#ft1b"><span class="sp">1</span></a> He records attempts made to determine
+the circumference; but the first scientific investigation in this
+<span class="pagenum"><a name="page800" id="page800"></a>800</span>
+direction was made 150 years later by Eratosthenes. The
+spherical form, however, only became generally accepted after
+the Earth&rsquo;s circumnavigation (see <span class="sc"><a href="#artlinks">Geography</a></span>).</p>
+
+<p>The historical development of the methods for determining
+the figure of the Earth (by which we mean a theoretical surface
+in part indicated by the ocean at rest, and in other parts by the
+level to which water freely communicating with the oceans
+by canals traversing the land masses would rise) and the mathematical
+investigation of this problem are treated in the articles
+<span class="sc"><a href="#artlinks">Earth, Figure of the</a></span>, and <span class="sc"><a href="#artlinks">Geodesy</a></span>; here the results are
+summarized. Sir Isaac Newton deduced from the mechanical
+consideration of the figure of equilibrium of a mass of rotating
+fluid, the form of an oblate spheroid, the ellipticity of a meridian
+section being 1/231, and the axes in the ratio 230 : 231. Geodetic
+measurements by the Cassinis and other French astronomers
+pointed to a prolate form, but the Newtonian figure was
+proved to be correct by the measurement of meridional arcs
+in Peru and Lapland by the expeditions organized by the
+French Academy of Sciences. More recent work points
+to an elliptical equatorial section, thus making the earth
+pear-shaped. The position of the longer axis is somewhat uncertain;
+it is certainly in Africa, Clarke placing it in longitude
+8° 15&prime; W., and Schubert in longitude 41° 4&prime; E.; W.J. Sollas,
+arguing from terrestrial symmetry, has chosen the position
+lat. 6° N., long. 28° E., <i>i.e.</i> between Clarke&rsquo;s and Schubert&rsquo;s
+positions. For the lengths of the axes and the ellipticity of the
+Earth, see <span class="sc"><a href="#artlinks">Earth, Figure of the</a></span>.</p>
+
+<p>2. <i>Mass and Density.</i>&mdash;The earliest scientific investigation
+on the density and mass of the Earth (the problem is really single
+if the volume of the Earth be known) was made by Newton, who,
+mainly from astronomical considerations, suggested the limiting
+densities 5 and 6; it is remarkable that this prophetic guess
+should be realized, the mean value from subsequent researches
+being about 5½, which gives for the mass the value 6 × 10<span class="sp">21</span> tons.
+The density of the Earth has been determined by several experimenters
+within recent years by methods described in the article
+<span class="sc"><a href="#artlinks">Gravitation</a></span>; the most probable value is there stated to be
+5.527.</p>
+
+<p>3. <i>Astronomical Relations.</i>&mdash;The grandest achievements of
+astronomical science are undoubtedly to be associated with
+the elucidation of the complex motion of our planet. The
+notion that the Earth was fixed and immovable at the centre
+of an immeasurable universe long possessed the minds of men;
+and we find the illustrious Ptolemy accepting this view in the
+2nd century <span class="scs">A.D.</span>, and rejecting the notion of a rotating Earth&mdash;a
+theory which had been proposed as early as the 5th century
+<span class="scs">B.C.</span> by Philolaus on philosophical grounds, and in the 3rd century
+<span class="scs">B.C.</span> by the astronomer Aristarchus of Samos. He argued that
+if the Earth rotated then points at the equator had the enormous
+velocity of about 1000 m. per hour, and as a consequence there
+should be terrific gales from the east; the fact that there were
+no such gales invalidated, in his opinion, the theory. The
+Ptolemaic theory was unchallenged until 1543, in which year the
+<i>De Revolutionibus orbium Celestium</i> of Copernicus was published.
+In this work it was shown that the common astronomical
+phenomena could be more simply explained by regarding
+the Earth as annually revolving about a fixed Sun, and daily
+rotating about itself. A clean sweep was made of the geocentric
+epicyclic motions of the planets which Ptolemy&rsquo;s theory demanded,
+and in place there was substituted a procession of planets
+about the Sun at different distances. The development of the
+Copernican theory&mdash;the corner-stone of modern astronomy&mdash;by
+Johann Kepler and Sir Isaac Newton is treated in the article
+<span class="sc"><a href="#artlinks">Astronomy</a></span>: <i>History</i>; here we shall summarily discuss the
+motions of our planet and its relation to the solar system.</p>
+
+<p>The Earth has two principal motions&mdash;revolution about the
+Sun, rotation about its axis; there are in addition a number
+of secular motions.</p>
+
+<p><i>Revolution.</i>&mdash;The Earth revolves about the Sun in an
+elliptical orbit having the Sun at one focus. The plane of the
+orbit is termed the ecliptic; it is inclined to the Earth&rsquo;s equator
+at an angle termed the obliquity, and the points of intersection
+of the equator and ecliptic are termed the equinoctial points.
+The major axis of the ellipse is the line of apsides; when the
+Earth is nearest the Sun it is said to be in perihelion, when
+farthest it is in aphelion. The mean distance of the Earth from
+the Sun is a most important astronomical constant, since it is
+the unit of linear measurement; its value is about 93,000,000 m.,
+and the difference between the perihelion and aphelion distances
+is about 3,000,000 m. The eccentricity of the orbit is 0.016751.
+A tabular comparison of the orbital constants of the Earth and
+the other planets is given in the article <span class="sc"><a href="#artlinks">Planet</a></span>. The period
+of revolution with regard to the Sun, or, in other words, the time
+taken by the Sun apparently to pass from one equinox to the
+same equinox, is the tropical or equinoctial year; its length is
+365 d. 5 hrs. 48 m. 46 secs. It is about 20 minutes shorter than
+the true or sidereal year, which is the time taken for the Sun
+apparently to travel from one star to it again. The difference
+in these two years is due to the secular variation termed precession
+(see below). A third year is named the <i>anomalistic year</i>,
+which is the time occupied in the passage from perihelion to
+perihelion; it is a little longer than the sidereal.</p>
+
+<p><i>Rotation.</i>&mdash;The Earth rotates about an axis terminating
+at the north and south geographical poles, and perpendicular
+to the equator; the period of rotation is termed the day (<i>q.v.</i>),
+of which several kinds are distinguished according to the body
+or point of reference. The rotation is performed from west to
+east; this daily rotation occasions the <i>diurnal</i> motion of the
+celestial sphere, the rising of the Sun and stars in the east and
+their setting in the west, and also the phenomena of day and
+night. The inclination of the axis to the ecliptic brings about
+the presentation of places in different latitudes to the more direct
+rays of the sun; this is revealed in the variation in the length of
+daylight with the time of the year, and the phenomena of seasons.</p>
+
+<p>Although the rotation of the Earth was an accepted fact soon
+after its suggestion by Copernicus, an experimental proof was
+wanting until 1851, when Foucault performed his celebrated
+pendulum experiment at the Pantheon, Paris. A pendulum
+about 200 ft. long, composed of a flexible wire carrying a heavy
+iron bob, was suspended so as to be free to oscillate in any direction.
+The bob was provided with a style which passed over a
+table strewn with fine sand, so that the style traced the direction
+in which the bob was swinging. It was found that the oscillating
+pendulum never retraced its path, but at each swing it was
+apparently deviated to the right, and moreover the deviations
+in equal times were themselves equal. This means that the floor
+of the Pantheon was moving, and therefore the Earth was
+rotating. If the pendulum were swung in the southern hemisphere,
+the deviation would be to the left; if at the equator it
+would not deviate, while at the poles the plane of oscillation would
+traverse a complete circle in 24 hours.</p>
+
+<p>The rotation of the Earth appears to be perfectly uniform,
+comparisons of the times of transits, eclipses, &amp;c., point to a
+variation of less than <span class="spp">1</span>&frasl;<span class="suu">100</span>th of a second since the time of Ptolemy.
+Theoretical investigations on the phenomena of tidal friction
+point, however, to a retardation, which may to some extent be
+diminished by the accelerations occasioned by the shrinkage of
+the globe, and some other factors difficult to evaluate (see <span class="sc"><a href="#artlinks">Tide</a></span>).</p>
+
+<p>We now proceed to the secular variations.</p>
+
+<p><i>Precession.</i>&mdash;The axis of the earth does not preserve an invariable
+direction in space, but in a certain time it describes a
+cone, in much the same manner as the axis of a top spinning out
+of the vertical. The equator, which preserves approximately
+the same inclination to the ecliptic (there is a slight variation in
+the obliquity which we shall mention later), must move so that
+its intersections with the ecliptic, or equinoctial points, pass in
+a retrograde direction, <i>i.e.</i> opposite to that of the Earth. This
+motion is termed the precession of the equinoxes, and was observed
+by Hipparchus in the 2nd century <span class="scs">B.C.</span>; Ptolemy corrected the
+catalogue of Hipparchus for precession by adding 2° 40&prime; to the
+longitudes, the latitudes being unaltered by this motion, which at
+the present time is 50.26&Prime; annually, the complete circuit being
+made in about 26,000 years. Owing to precession the signs of
+the zodiac are traversing paths through the constellations, or,
+<span class="pagenum"><a name="page801" id="page801"></a>801</span>
+in other words, the constellations are continually shifting with
+regard to the equinoctial points; at one time the vernal equinox
+Aries was in the constellations of that name; it is now in Pisces,
+and will then pass into Aquarius. The pole star, <i>i.e.</i> the star
+towards which the Earth&rsquo;s axis points, is also shifting owing to
+precession; in about 2700 <span class="scs">B.C.</span> the Chinese observed &alpha; Draconis
+as the pole star (at present &alpha; Ursae minoris occupies this position
+and will do so until 3500); in 13600 Vega (&alpha; Lyrae) the brightest
+star in the Northern hemisphere, will be nearest.</p>
+
+<p>Precession is the result of the Sun and the Moon&rsquo;s attraction
+on the Earth not being a single force through its centre of gravity.
+If the Earth were a homogeneous sphere the attractions would
+act through the centre, and such forces would have no effect
+upon the rotation about the centre of gravity, but the Earth
+being spheroidal the equatorial band which stands up as it were
+beyond the surface of a sphere is more strongly attracted, with
+the result that the axis undergoes a tilting. The precession due
+to the Sun is termed the <i>solar precession</i> and that due to the
+Moon the <i>lunar precession</i>; the joint effect (two-thirds of which
+is due to the Moon) is the <i>luni-solar</i> precession. Solar precession
+is greatest at the solstices and zero at the equinoxes; the part
+of luni-solar precession due to the Moon varies with the position
+of the Moon in its orbit. The obliquity is unchanged by precession
+(see <span class="sc"><a href="#artlinks">Precession of the Equinoxes</a></span>).</p>
+
+<p><i>Nutation.</i>&mdash;In treating precession we have stated that the axis
+of the Earth traces a cone, and it follows that the pole describes
+a circle (approximately) on the celestial sphere, about the pole
+of the ecliptic. This is not quite true. Irregularities in the
+attracting forces which occasion precession also cause a slight
+oscillation backwards and forwards over the mean precessional
+path of the pole, the pole tracing a wavy line or nodding. Both
+the Sun and Moon contribute to this effect. Solar nutation
+depends upon the position of the Sun on the ecliptic; its period
+is therefore 1 year, and in extent it is only 1.2&Prime;; lunar nutation
+depends upon the position of the Moon&rsquo;s nodes; its period is
+therefore about 18.6 years, the time of revolution of the nodes,
+and its extent is 9.2&Prime;. There is also given to the obliquity a small
+oscillation to and fro. Nutation is one of the great discoveries
+of James Bradley (1747).</p>
+
+<p><i>Planetary Precession.</i>&mdash;So far we have regarded the ecliptic as
+absolutely fixed, and treated precession as a real motion of the
+equator. The ecliptic (<i>q.v.</i>), however, is itself subject to a motion,
+due to the attractions of the planets on the Earth. This effect
+also displaces the equinoctial points. Its annual value is 0.13&Prime;.
+The term General Precession in longitude is given to the displacement
+of the intersection of the equator with the apparent
+ecliptic on the latter. The standard value is 50.2453&Prime;, which
+prevailed in 1850, and the value at 1850 + t, <i>i.e.</i> the constant of
+precession, is 50.2453&Prime; + 0.0002225&Prime; t. This value is also liable
+to a very small change. The nutation of the obliquity at time
+1850 + t is given by the formula 23° 27&prime; 32.0&Prime; &minus; 0.47&Prime; t. Complete
+expressions for these functions are given in Newcomb&rsquo;s
+<i>Spherical Astronomy</i> (1908), and in the <i>Nautical Almanac</i>.</p>
+
+<p>The variation of the <i>line of apsides</i> is the name given to the
+motion of the major axis of the Earth&rsquo;s orbit along the ecliptic.
+It is due to the general influence of the planets, and the revolution
+is effected in 21,000 years.</p>
+
+<p>The variation of the eccentricity denotes an oscillation of the
+form of the Earth&rsquo;s orbit between a circle and ellipse. This
+followed the mathematical researches of Lagrange and Leverrier.
+It was suggested by Sir John Herschel in 1830 that this variation
+might occasion great climatic changes, and James Croll developed
+the theory as affording a solution of the glacial periods in geology
+(<i>q.v.</i>).</p>
+
+<p><i>Variation of Latitude.</i>&mdash;Another secular motion of the Earth
+is due to the fact that the axis of rotation is not rigidly fixed
+within it, but its polar extremities wander in a circle of about
+50 ft. diameter. This oscillation brings about a variability
+in terrestrial latitudes, hence the name. Euler showed mathematically
+that such an oscillation existed, and, making certain
+assumptions as to the rigidity of the Earth, deduced that its
+period was 305 days; S.C. Chandler, from 1890 onwards,
+deduced from observations of the stars a period of 428 days;
+and Simon Newcomb explained the deviation of these periods
+by pointing out that Euler&rsquo;s assumption of a perfectly rigid
+Earth is not in accordance with fact. For details of this intricate
+subject see the articles <span class="sc"><a href="#artlinks">Latitude</a></span> and <span class="sc"><a href="#artlinks">Earth, Figure of the</a></span>.</p>
+
+<p>4. <i>Evolution and Age.</i>&mdash;In its earliest history the mass now
+consolidated as the Earth and Moon was part of a vast nebulous
+aggregate, which in the course of time formed a central nucleus&mdash;our
+Sun&mdash;which shed its outer layers in such a manner as to
+form the solar system (see <span class="sc"><a href="#artlinks">Nebular Theory</a></span>). The moon may
+have been formed from the Earth in a similar manner, but the
+theory of tidal friction suggests the elongation of the Earth along
+an equatorial axis to form a pear-shaped figure, and that in the
+course of time the protuberance shot off to form the Moon
+(see <span class="sc"><a href="#artlinks">Tide</a></span>). The age of the Earth has been investigated from
+several directions, as have also associated questions related to
+climatic changes, internal temperature, orientation of the land
+and water (permanence of oceans and continents), &amp;c. These
+problems are treated in the articles <span class="sc"><a href="#artlinks">Geology</a></span> and <span class="sc"><a href="#artlinks">Geography</a></span>.</p>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1b" id="ft1b" href="#fa1b"><span class="fn">1</span></a> Aristotle regarded the Earth as having an upper inhabited half
+and a lower uninhabited one, and the air on the lower half as tending
+to flow upwards through the Earth. The obstruction of this passage
+brought about an accumulation of air within the Earth, and the
+increased pressure may occasion oscillations of the surface, which
+may be so intense as to cause earthquakes.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARTH, FIGURE OF THE.<a name="ar41" id="ar41"></a></span> The determination of the figure
+of the earth is a problem of the highest importance in astronomy,
+inasmuch as the diameter of the earth is the unit to which all
+celestial distances must be referred.</p>
+
+<p class="pt2 center"><i>Historical.</i></p>
+
+<p>Reasoning from the uniform level appearance of the horizon,
+the variations in altitude of the circumpolar stars as one travels
+towards the north or south, the disappearance of a ship standing
+out to sea, and perhaps other phenomena, the earliest astronomers
+regarded the earth as a sphere, and they endeavoured
+to ascertain its dimensions. Aristotle relates that the mathematicians
+had found the circumference to be 400,000 stadia (about
+46,000 miles). But Eratosthenes (<i>c.</i> 250 <span class="scs">B.C.</span>) appears to have
+been the first who entertained an accurate idea of the principles
+on which the determination of the figure of the earth really depends,
+and attempted to reduce them to practice. His results
+were very inaccurate, but his method is the same as that which is
+followed at the present day&mdash;depending, in fact, on the comparison
+of a line measured on the earth&rsquo;s surface with the corresponding
+arc of the heavens. He observed that at Syene in Upper Egypt,
+on the day of the summer solstice, the sun was exactly vertical,
+whilst at Alexandria at the same season of the year its zenith
+distance was 7° 12&prime;, or one-fiftieth of the circumference of a
+circle. He assumed that these places were on the same meridian;
+and, reckoning their distance apart as 5000 stadia, he inferred
+that the circumference of the earth was 250,000 stadia (about
+29,000 miles). A similar attempt was made by Posidonius, who
+adopted a method which differed from that of Eratosthenes only
+in using a star instead of the sun. He obtained 240,000 stadia
+(about 27,600 miles) for the circumference. Ptolemy in his
+<i>Geography</i> assigns the length of the degree as 500 stadia.</p>
+
+<p>The Arabs also investigated the question of the earth&rsquo;s magnitude.
+The caliph Abdallah al Mamun (<span class="scs">A.D.</span> 814), having fixed
+on a spot in the plains of Mesopotamia, despatched one company
+of astronomers northwards and another southwards, measuring
+the journey by rods, until each found the altitude of the pole
+to have changed one degree. But the result of this measurement
+does not appear to have been very satisfactory. From this
+time the subject seems to have attracted no attention until about
+1500, when Jean Fernel (1497-1558), a Frenchman, measured
+a distance in the direction of the meridian near Paris by counting
+the number of revolutions of the wheel of a carriage. His
+astronomical observations were made with a triangle used as a
+quadrant, and his resulting length of a degree was very near the
+truth.</p>
+
+<p>Willebrord Snell<a name="fa1c" id="fa1c" href="#ft1c"><span class="sp">1</span></a> substituted a chain of triangles for actual
+linear measurement. He measured his base line on the frozen
+surface of the meadows near Leiden, and measured the angles of
+his triangles, which lay between Alkmaar and Bergen-op-Zoom,
+with a quadrant and semicircles. He took the precaution of
+<span class="pagenum"><a name="page802" id="page802"></a>802</span>
+comparing his standard with that of the French, so that his
+result was expressed in toises (the length of the toise is about
+6.39 English ft.). The work was recomputed and reobserved
+by P. von Musschenbroek in 1729. In 1637 an Englishman,
+Richard Norwood, published a determination of the figure of the
+earth in a volume entitled <i>The Seaman&rsquo;s Practice, contayning
+a Fundamentall Probleme in Navigation experimentally verified,
+namely, touching the Compasse of the Earth and Sea and the
+quantity of a Degree in our English Measures</i>. He observed on
+the 11th of June 1633 the sun&rsquo;s meridian altitude in London
+as 62° 1&prime;, and on the 6th of June 1635, his meridian altitude
+in York as 59° 33&prime;. He measured the distance between these
+places partly with a chain and partly by pacing. By this means,
+through compensation of errors, he arrived at 367,176 ft. for the
+degree&mdash;a very fair result.</p>
+
+<p>The application of the telescope to angular instruments was
+the next important step. Jean Picard was the first who in 1669,
+with the telescope, using such precautions as the nature of the
+operation requires, measured an arc of meridian. He measured
+with wooden rods a base line of 5663 toises, and a second or base
+of verification of 3902 toises; his triangulation extended from
+Malvoisine, near Paris, to Sourdon, near Amiens. The angles
+of the triangles were measured with a quadrant furnished with
+a telescope having cross-wires. The difference of latitude of the
+terminal stations was determined by observations made with a
+sector on a star in Cassiopeia, giving 1° 22&prime; 55&Prime; for the amplitude.
+The terrestrial measurement gave 78,850 toises, whence he inferred
+for the length of the degree 57,060 toises.</p>
+
+<p>Hitherto geodetic observations had been confined to the
+determination of the magnitude of the earth considered as a
+sphere, but a discovery made by Jean Richer (d. 1696) turned
+the attention of mathematicians to its deviation from a spherical
+form. This astronomer, having been sent by the Academy of
+Sciences of Paris to the island of Cayenne, in South America,
+for the purpose of investigating the amount of astronomical
+refraction and other astronomical objects, observed that his
+clock, which had been regulated at Paris to beat seconds, lost
+about two minutes and a half daily at Cayenne, and that in order
+to bring it to measure mean solar time it was necessary to shorten
+the pendulum by more than a line (about <span class="spp">1</span>&frasl;<span class="suu">12</span>th of an in.). This
+fact, which was scarcely credited till it had been confirmed by
+the subsequent observations of Varin and Deshayes on the coasts
+of Africa and America, was first explained in the third book of
+Newton&rsquo;s <i>Principia</i>, who showed that it could only be referred
+to a diminution of gravity arising either from a protuberance of
+the equatorial parts of the earth and consequent increase of the
+distance from the centre, or from the counteracting effect of the
+centrifugal force. About the same time (1673) appeared Christian
+Huygens&rsquo; <i>De Horologio Oscillatorio</i>, in which for the first time
+were found correct notions on the subject of centrifugal force.
+It does not, however, appear that they were applied to the
+theoretical investigation of the figure of the earth before the
+publication of Newton&rsquo;s <i>Principia</i>. In 1690 Huygens published
+his <i>De Causa Gravitatis</i>, which contains an investigation of the
+figure of the earth on the supposition that the attraction of every
+particle is towards the centre.</p>
+
+<p>Between 1684 and 1718 J. and D. Cassini, starting from
+Picard&rsquo;s base, carried a triangulation northwards from Paris
+to Dunkirk and southwards from Paris to Collioure. They
+measured a base of 7246 toises near Perpignan, and a somewhat
+shorter base near Dunkirk; and from the northern portion of
+the arc, which had an amplitude of 2° 12&prime; 9&Prime;, obtained for the
+length of a degree 56,960 toises; while from the southern portion,
+of which the amplitude was 6° 18&prime; 57&Prime;, they obtained 57,097
+toises. The immediate inference from this was that, the degree
+diminishing with increasing latitude, the earth must be a prolate
+spheroid. This conclusion was totally opposed to the theoretical
+investigations of Newton and Huygens, and accordingly the
+Academy of Sciences of Paris determined to apply a decisive
+test by the measurement of arcs at a great distance from each
+other&mdash;one in the neighbourhood of the equator, the other in a
+high latitude. Thus arose the celebrated expeditions of the French
+academicians. In May 1735 Louis Godin, Pierre Bouguer and
+Charles Marie de la Condamine, under the auspices of Louis XV.,
+proceeded to Peru, where, assisted by two Spanish officers, after
+ten years of laborious exertion, they measured an arc of 3° 7&prime;,
+the northern end near the equator. The second party consisted
+of Pierre Louis Moreau de Maupertuis, Alexis Claude Clairault,
+Charles Étienne Louis Camus, Pierre Charles Lemonnier, and
+Reginaud Outhier, who reached the Gulf of Bothnia in July 1736;
+they were in some respects more fortunate than the first party,
+inasmuch as they completed the measurement of an arc near the
+polar circle of 57&prime; amplitude and returned within sixteen months
+from the date of their departure.</p>
+
+<p>The measurement of Bouguer and De la Condamine was
+executed with great care, and on account of the locality, as well
+as the manner in which all the details were conducted, it has
+always been regarded as a most valuable determination. The
+southern limit was at Tarqui, the northern at Cotchesqui. A base
+of 6272 toises was measured in the vicinity of Quito, near the
+northern extremity of the arc, and a second base of 5260 toises
+near the southern extremity. The mountainous nature of the
+country made the work very laborious, in some cases the difference
+of heights of two neighbouring stations exceeding 1 mile;
+and they had much trouble with their instruments, those with
+which they were to determine the latitudes proving untrustworthy.
+But they succeeded by simultaneous observations of
+the same star at the two extremities of the arc in obtaining very
+fair results. The whole length of the arc amounted to 176,945
+toises, while the difference of latitudes was 3° 7&prime; 3&Prime;. In consequence
+of a misunderstanding that arose between De la Condamine
+and Bouguer, their operations were conducted separately,
+and each wrote a full account of the expedition. Bouguer&rsquo;s
+book was published in 1749; that of De la Condamine in 1751.
+The toise used in this measure was afterwards regarded as the
+standard toise, and is always referred to as the <i>Toise of Peru</i>.</p>
+
+<p>The party of Maupertuis, though their work was quickly
+despatched, had also to contend with great difficulties. Not
+being able to make use of the small islands in the Gulf of Bothnia
+for the trigonometrical stations, they were forced to penetrate
+into the forests of Lapland, commencing operations at Torneå,
+a city situated on the mainland near the extremity of the gulf.
+From this, the southern extremity of their arc, they carried a
+chain of triangles northward to the mountain Kittis, which they
+selected as the northern terminus. The latitudes were determined
+by observations with a sector (made by George Graham) of the
+zenith distance of &alpha; and &delta; Draconis. The base line was measured
+on the frozen surface of the river Torneå about the middle of the
+arc; two parties measured it separately, and they differed by
+about 4 in. The result of the whole was that the difference of
+latitudes of the terminal stations was 57&prime; 29&Prime; .6, and the length
+of the arc 55,023 toises. In this expedition, as well as in that to
+Peru, observations were made with a pendulum to determine
+the force of gravity; and these observations coincided with the
+geodetic results in proving that the earth was an oblate and not
+prolate spheroid.</p>
+
+<p>In 1740 was published in the Paris <i>Mémoires</i> an account, by
+Cassini de Thury, of a remeasurement by himself and Nicolas
+Louis de Lacaille of the meridian of Paris. With a view to
+determine more accurately the variation of the degree along the
+meridian, they divided the distance from Dunkirk to Collioure
+into four partial arcs of about two degrees each, by observing the
+latitude at five stations. The results previously obtained by
+J. and D. Cassini were not confirmed, but, on the contrary,
+the length of the degree derived from these partial arcs showed
+on the whole an increase with an increasing latitude. Cassini
+and Lacaille also measured an arc of parallel across the mouth
+of the Rhone. The difference of time of the extremities was
+determined by the observers at either end noting the instant
+of a signal given by flashing gunpowder at a point near the
+middle of the arc.</p>
+
+<p>While at the Cape of Good Hope in 1752, engaged in various
+astronomical observations, Lacaille measured an arc of meridian
+of 1° 13&prime; 17&Prime;, which gave him for the length of the degree 57,037
+<span class="pagenum"><a name="page803" id="page803"></a>803</span>
+toises&mdash;an unexpected result, which has led to the remeasurement
+of the arc by Sir Thomas Maclear (see <span class="sc"><a href="#artlinks">Geodesy</a></span>).</p>
+
+<p>Passing over the measurements made between Rome and
+Rimini and on the plains of Piedmont by the Jesuits Ruggiero
+Giuseppe Boscovich and Giovanni Battista Beccaria, and also the
+arc measured with deal rods in North America by Charles Mason
+and Jeremiah Dixon, we come to the commencement of the
+English triangulation. In 1783, in consequence of a representation
+from Cassini de Thury on the advantages that would accrue
+from the geodetic connexion of Paris and Greenwich, General
+William Roy was, with the king&rsquo;s approval, appointed by the
+Royal Society to conduct the operations on the part of England,
+Count Cassini, Méchain and Delambre being appointed on the
+French side. A precision previously unknown was attained
+by the use of Ramsden&rsquo;s theodolite, which was the first to make
+the spherical excess of triangles measurable. The wooden rods
+with which the first base was measured were replaced by glass
+rods, which were afterwards rejected for the steel chain of
+Ramsden. (For further details see <i>Account of the Trigonometrical
+Survey of England and Wales</i>.)</p>
+
+<p>Shortly after this, the National Convention of France, having
+agreed to remodel their system of weights and measures, chose for
+their unit of length the ten-millionth part of the meridian
+quadrant. In order to obtain this length precisely, the remeasurement
+of the French meridian was resolved on, and
+deputed to J.B.J. Delambre and Pierre François André Méchain.
+The details of this operation will be found in the <i>Base du système
+métrique décimale</i>. The arc was subsequently extended by
+Jean Baptiste Biot and Dominique François Jean Arago to
+the island of Iviza. Operations for the connexion of England
+with the continent of Europe were resumed in 1821 to 1823 by
+Henry Kater and Thomas Frederick Colby on the English side,
+and F.J.D. Arago and Claude Louis Mathieu on the French.</p>
+
+<p>The publication in 1838 of Friedrich Wilhelm Bessel&rsquo;s <i>Gradmessung
+in Ostpreussen</i> marks an era in the science of geodesy.
+Here we find the method of least squares applied to the calculation
+of a network of triangles and the reduction of the
+observations generally. The systematic manner in which all
+the observations were taken with the view of securing final
+results of extreme accuracy is admirable. The triangulation,
+which was a small one, extended about a degree and a half
+along the shores of the Baltic in a N.N.E. direction. The
+angles were observed with theodolites of 12 and 15 in. diameter,
+and the latitudes determined by means of the transit instrument
+in the prime vertical&mdash;a method much used in Germany.
+(The base apparatus is described in the article <span class="sc"><a href="#artlinks">Geodesy</a></span>.)</p>
+
+<p>The principal triangulation of Great Britain and Ireland,
+which was commenced in 1783 under General Roy, for the more
+immediate purpose of connecting the observatories of Greenwich
+and Paris, had been gradually extended, under the successive
+direction of Colonel E. Williams, General W. Mudge, General
+T.F. Colby, Colonel L.A. Hall, and Colonel Sir Henry James;
+it was finished in 1851. The number of stations is about 250.
+At 32 of these the latitudes were determined with Ramsden&rsquo;s
+and Airy&rsquo;s zenith sectors. The theodolites used for this work
+were, in addition to the two great theodolites of Ramsden which
+were used by General Roy and Captain Kater, a smaller theodolite
+of 18 in. diameter by the same mechanician, and another
+of 24 in. diameter by Messrs Troughton and Simms. Observations
+for determination of absolute azimuth were made with
+those instruments at a large number of stations; the stars
+&alpha;, &delta;, and &lambda; Ursae Minoris and 51 Cephei being those observed
+always at the greatest azimuths. At six of these stations the
+probable error of the result is under 0.4&Prime;, at twelve under 0.5&Prime;,
+at thirty-four under 0.7&Prime;: so that the absolute azimuth of the
+whole network is determined with extreme accuracy. Of the
+seven base lines which have been measured, five were by means
+of steel chains and two with Colby&rsquo;s compensation bars (see
+<span class="sc"><a href="#artlinks">Geodesy</a></span>). The triangulation was computed by least squares.
+The total number of equations of condition for the triangulation
+is 920; if therefore the whole had been reduced in one mass, as
+it should have been, the solution of an equation of 920 unknown
+quantities would have occurred as a part of the work. To
+avoid this an approximation was resorted to; the triangulation
+was divided into twenty-one parts or figures; four of these,
+not adjacent, were first adjusted by the method explained, and
+the corrections thus determined in these figures carried into
+the equations of condition of the adjacent figures. The average
+number of equations in a figure is 44; the largest equation
+is one of 77 unknown quantities. The vertical limb of Airy&rsquo;s
+zenith sector is read by four microscopes, and in the complete
+observation of a star there are 10 micrometer readings and 12
+level readings. The instrument is portable; and a complete
+determination of latitude, affected with the mean of the declination
+errors of two stars, is effected by two micrometer readings
+and four level readings. The observation consists in measuring
+with the telescope micrometer the difference of zenith distances
+of two stars which cross the meridian, one to the north and
+the other to the south of the observer at zenith distances which
+differ by not much more than 10&prime; or 15&prime;, the interval of the times of
+transit being not less than one nor more than twenty minutes.
+The advantages are that, with simplicity in the construction of the
+instrument and facility in the manipulation, refraction is eliminated
+(or nearly so, as the stars are generally selected within
+25° of the zenith), and there is no large divided circle. The
+telescope, which is counterpoised on one side of the vertical
+axis, has a small circle for finding, and there is also a small
+horizontal circle. This instrument is universally used in
+American geodesy.</p>
+
+<div class="condensed">
+<p>The principal work containing the methods and results of these
+operations was published in 1858 with the title &ldquo;Ordnance Trigonometrical
+Survey of Great Britain and Ireland. Account of the
+observations and calculations of the principal triangulation and of
+the figure, dimensions and mean specific gravity of the earth as
+derived therefrom. Drawn up by Captain Alexander Ross Clarke,
+R.E., F.R.A.S., under the direction of Lieut.-Colonel H. James,
+R.E., F.R.S., M.R.I.A., &amp;c.&rdquo; A supplement appeared in 1862:
+&ldquo;Extension of the Triangulation of the Ordnance Survey into
+France and Belgium, with the measurement of an arc of parallel in
+52° N. from Valentia in Ireland to Mount Kemmel in Belgium.
+Published by ... Col. Sir Henry James.&rdquo;</p>
+</div>
+
+<p>Extensive operations for surveying India and determining
+the figure of the earth were commenced in 1800. Colonel W.
+Lambton started the great meridian arc at Punnae in latitude
+8° 9&prime;, and, following generally the methods of the English survey,
+he carried his triangulation as far north as 20° 30&prime;. The work
+was continued by Sir George (then Captain) Everest, who carried
+it to the latitude of 29° 30&prime;. Two admirable volumes by Sir
+George Everest, published in 1830 and in 1847, give the details
+of this undertaking. The survey was afterwards prosecuted by
+Colonel T.T. Walker, R.E., who made valuable contributions
+to geodesy. The working out of the Indian chains of triangle
+by the method of least squares presents peculiar difficulties,
+but, enormous in extent as the work was, it has been thoroughly
+carried out. The ten base lines on which the survey depends
+were measured with Colby&rsquo;s compensation bars.</p>
+
+<div class="condensed">
+<p>The survey is detailed in eighteen volumes, published at Dehra
+Dun, and entitled <i>Account of the Operations of the Great Trigonometrical
+Survey of India</i>. Of these the first nine were published
+under the direction of Colonel Walker; and the remainder by
+Colonels Strahan and St G.C. Gore, Major S.G. Burrard and others.
+Vol. i., 1870, treats of the base lines; vol. ii., 1879, history and general
+descriptions of the principal triangulation and of its reduction;
+vol. v., 1879, pendulum operations (Captains T.P. Basevi and W.T.
+Heaviside); vols. xi., 1890, and xviii., 1906, latitudes; vols. ix., 1883,
+x., 1887, xv., 1893, longitudes; vol. xvii., 1901, the Indo-European
+longitude-arcs from Karachi to Greenwich. The other volumes contain
+the triangulations.</p>
+</div>
+
+<p>In 1860 Friedrich Georg Wilhelm Struve published his <i>Arc du
+méridien de 25° 20&prime; entre le Danube et la Mer Glaciale mesuré
+depuis 1816 jusqu&rsquo;en 1855</i>. The latitudes of the thirteen astronomical
+stations of this arc were determined partly with vertical
+circles and partly by means of the transit instrument in the prime
+vertical. The triangulation, a great part of which, however,
+is a simple chain of triangles, is reduced by the method of least
+squares, and the probable errors of the resulting distances of
+parallels is given; the probable error of the whole arc in length
+is ± 6.2 toises. Ten base lines were measured. The sum of the
+<span class="pagenum"><a name="page804" id="page804"></a>804</span>
+lengths of the ten measured bases is 29,863 toises, so that the
+average length of a base line is 19,100 ft. The azimuths were
+observed at fourteen stations. In high latitudes the determination
+of the meridian is a matter of great difficulty; nevertheless
+the azimuths at all the northern stations were successfully
+determined,&mdash;the probable error of the result at Fuglenaes being
+± 0&Prime;.53.</p>
+
+<p>Before proceeding with the modern developments of geodetic
+measurements and their application to the figure of the earth,
+we must discuss the &ldquo;mechanical theory,&rdquo; which is indispensable
+for a full understanding of the subject.</p>
+
+<p class="pt2 center"><i>Mechanical Theory.</i></p>
+
+<p>Newton, by applying his theory of gravitation, combined
+with the so-called centrifugal force, to the earth, and assuming
+that an oblate ellipsoid of rotation is a form of equilibrium for
+a homogeneous fluid rotating with uniform angular velocity,
+obtained the ratio of the axes 229:230, and the law of variation
+of gravity on the surface. A few years later Huygens published
+an investigation of the figure of the earth, supposing the attraction
+of every particle to be towards the centre of the earth,
+obtaining as a result that the proportion of the axes should be
+578 : 579. In 1740 Colin Maclaurin, in his <i>De causa physica
+fluxus et refluxus maris</i>, demonstrated that the oblate ellipsoid
+of revolution is a figure which satisfies the conditions of equilibrium
+in the case of a revolving homogeneous fluid mass, whose
+particles attract one another according to the law of the inverse
+square of the distance; he gave the equation connecting the
+ellipticity with the proportion of the centrifugal force at the
+equator to gravity, and determined the attraction on a particle
+situated anywhere on the surface of such a body. In 1743
+Clairault published his <i>Théorie de la figure de la terre</i>, which
+contains a remarkable theorem (&ldquo;Clairault&rsquo;s Theorem&rdquo;), establishing
+a relation between the ellipticity of the earth and the
+variation of gravity from the equator to the poles. Assuming
+that the earth is composed of concentric ellipsoidal strata having
+a common axis of rotation, each stratum homogeneous in itself,
+but the ellipticities and densities of the successive strata varying
+according to any law, and that the superficial stratum has the
+same form as if it were fluid, he proved that</p>
+
+<table class="math0" summary="math">
+<tr><td>g&prime; &minus; g</td> <td rowspan="2">+ e =</td>
+<td>5</td> <td rowspan="2">m,</td></tr>
+<tr><td class="denom">g</td> <td class="denom">2</td></tr></table>
+
+<p class="noind">where g, g&prime; are the amounts of gravity at the equator and at
+the pole respectively, e the ellipticity of the meridian (or &ldquo;flattening&rdquo;),
+and m the ratio of the centrifugal force at the equator to g.
+He also proved that the increase of gravity in proceeding from
+the equator to the poles is as the square of the sine of the latitude.
+This, taken with the former theorem, gives the means of determining
+the earth&rsquo;s ellipticity from observation of the relative
+force of gravity at any two places. P.S. Laplace, who devoted
+much attention to the subject, remarks on Clairault&rsquo;s work that
+&ldquo;the importance of all his results and the elegance with which
+they are presented place this work amongst the most beautiful
+of mathematical productions&rdquo; (Isaac Todhunter&rsquo;s <i>History of the
+Mathematical Theories of Attraction and the Figure of the Earth</i>,
+vol. i. p. 229).</p>
+
+<p>The problem of the figure of the earth treated as a question
+of mechanics or hydrostatics is one of great difficulty, and it
+would be quite impracticable but for the circumstance that
+the surface differs but little from a sphere. In order to express
+the forces at any point of the body arising from the attraction
+of its particles, the form of the surface is required, but this form
+is the very one which it is the object of the investigation to
+discover; hence the complexity of the subject, and even with
+all the present resources of mathematicians only a partial and
+imperfect solution can be obtained.</p>
+
+<div class="condensed">
+<p>We may here briefly indicate the line of reasoning by which some
+of the most important results may be obtained. If X, Y, Z be the
+components parallel to three rectangular axes of the forces acting
+on a particle of a fluid mass at the point x, y, z, then, p being the
+pressure there, and &rho; the density,</p>
+
+<p class="center">dp = &rho;(Xdx + Ydy + Zdz);</p>
+
+<p>and for equilibrium the necessary conditions are, that &rho;(Xdx +
+Ydy + Zdz) be a complete differential, and at the free surface Xdx +
+Ydy + Zdz = 0. This equation implies that the resultant of the forces
+is normal to the surface at every point, and in a homogeneous fluid
+it is obviously the differential equation of all surfaces of equal pressure.
+If the fluid be heterogeneous then it is to be remarked that for
+forces of attraction according to the ordinary law of gravitation,
+if X, Y, Z be the components of the attraction of a mass whose
+potential is V, then</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Xdx + Ydy + Zdz =</td> <td>dV</td>
+<td rowspan="2">dx +</td> <td>dV</td>
+<td rowspan="2">dy +</td> <td>dV</td>
+<td rowspan="2">dz,</td></tr>
+<tr><td class="denom">dx</td> <td class="denom">dy</td> <td class="denom">dz</td></tr></table>
+
+<p class="noind">which is a complete differential. And in the case of a fluid rotating
+with uniform velocity, in which the so-called centrifugal force enters
+as a force acting on each particle proportional to its distance from
+the axis of rotation, the corresponding part of Xdx + Ydy + Zdz is
+obviously a complete differential. Therefore for the forces with
+which we are now concerned Xdx + Ydy + Zdz = dU, where U is some
+function of x, y, z, and it is necessary for equilibrium that dp = &rho;dU
+be a complete differential; that is, &rho; must be a function of U or a
+function of p, and so also p a function of U. So that dU = 0 is the
+differential equation of surfaces of equal pressure and density.</p>
+
+<p>We may now show that a homogeneous fluid mass in the form of
+an oblate ellipsoid of revolution having a uniform velocity of rotation
+can be in equilibrium. It may be proved that the attraction of the
+ellipsoid x² + y² + z²(1 + &epsilon;²) = c²(1 + &epsilon;²); upon a particle P of its mass at
+x, y, z has for components</p>
+
+<p class="center">X = &minus; Ax, Y = &minus; Ay, Z = &minus; Cz,</p>
+
+<p class="noind">where</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">A = 2&pi;k²&rho;<span class="f150">(</span></td> <td>1 + &epsilon;²</td>
+<td rowspan="2">tan<span class="sp">&minus;1</span>&epsilon; &minus;</td> <td>1</td>
+<td rowspan="2"><span class="f150">)</span>,</td></tr>
+<tr><td class="denom">&epsilon;³</td> <td class="denom">&epsilon;²</td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">C = 4&pi;k²&rho;<span class="f150">(</span></td> <td>1 + &epsilon;²</td>
+<td rowspan="2">&minus;</td> <td>1 + &epsilon;²</td>
+<td rowspan="2">tan<span class="sp">&minus;1</span>&epsilon;<span class="f150">)</span>,</td></tr>
+<tr><td class="denom">&epsilon;²</td> <td class="denom">&epsilon;³</td></tr></table>
+
+<p class="noind">and k² the constant of attraction. Besides the attraction of the mass
+of the ellipsoid, the centrifugal force at P has for components
++ x&omega;², + y&omega;², 0; then the condition of fluid equilibrium is</p>
+
+<p class="center">(A &minus; &omega;²)xdx + (A &minus; &omega;²)ydy + Czdz = 0,</p>
+
+<p class="noind">which by integration gives</p>
+
+<p class="center">(A &minus; &omega;²)(x² + y²) + Cz² = constant.</p>
+
+<p class="noind">This is the equation of an ellipsoid of rotation, and therefore the
+equilibrium is possible. The equation coincides with that of the surface
+of the fluid mass if we make</p>
+
+<p class="center">A &minus; &omega;² = C / (1 + &epsilon;²),</p>
+
+<p class="noind">which gives</p>
+
+<table class="math0" summary="math">
+<tr><td>&omega;²</td> <td rowspan="2">=</td>
+<td>3 + &epsilon;²</td> <td rowspan="2">tan<span class="sp">&minus;1</span>&epsilon; &minus;</td>
+<td>3</td> <td rowspan="2">.</td></tr>
+<tr><td class="denom">2&pi;k²&rho;</td> <td class="denom">&epsilon;³</td>
+<td class="denom">&epsilon;²</td></tr></table>
+
+<p>In the case of the earth, which is nearly spherical, we obtain by
+expanding the expression for &omega;² in powers of &epsilon;², rejecting the higher
+powers, and remarking that the ellipticity e = ½&epsilon;²,</p>
+
+<p class="center">&omega;² / 2&pi;k²&rho; = 4&epsilon;² / 15 = 8e / 15.</p>
+
+<p>Now if m be the ratio of the centrifugal force to the intensity of
+gravity at the equator, and a = c(1 + e), then</p>
+
+<p class="center">m = a&omega;² / <span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²&rho;a, &there4; &omega;² / 2&pi;k²&rho; = <span class="spp">2</span>&frasl;<span class="suu">3</span>m.</p>
+
+<p>In the case of the earth it is a matter of observation that
+m = 1/289, hence the ellipticity</p>
+
+<p class="center">e = 5m / 4 = 1/231,</p>
+
+<p class="noind">so that the ratio of the axes on the supposition of a homogeneous
+fluid earth is 230 : 231, as stated by Newton.</p>
+
+<p>Now, to come to the case of a heterogeneous fluid, we shall assume
+that its surfaces of equal density are spheroids, concentric and
+having a common axis of rotation, and that the ellipticity of these
+surfaces varies from the centre to the outer surface, the density also
+varying. In other words, the body is composed of homogeneous
+spheroidal shells of variable density and ellipticity. On this supposition
+we shall express the attraction of the mass upon a particle in
+its interior, and then, taking into account the centrifugal force, form
+the equation expressing the condition of fluid equilibrium. The
+attraction of the homogeneous spheroid x² + y² + z²(1  + 2e) = c²(1 + 2e),
+where e is the ellipticity (of which the square is neglected), on an
+internal particle, whose co-ordinates are x = f, y = 0, z = h, has for its
+x and z components</p>
+
+<p class="center">X&prime; = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²&rho;f(1 &minus; <span class="spp">2</span>&frasl;<span class="suu">5</span>e), &emsp; Z&prime; = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²&rho;h(1 + <span class="spp">4</span>&frasl;<span class="suu">5</span>e),</p>
+
+<p class="noind">the Y component being of course zero. Hence we infer that the attraction
+of a shell whose inner surface has an ellipticity e, and its
+outer surface an ellipticity e + de, the density being &rho;, is expressed by</p>
+
+<p class="center">dX&prime; = <span class="spp">4</span>&frasl;<span class="suu">3</span> · <span class="spp">2</span>&frasl;<span class="suu">5</span>&pi;k²&rho;f de, &emsp; dZ&prime; = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span> · <span class="spp">4</span>&frasl;<span class="suu">5</span>&pi;k²&rho;h de.</p>
+
+<p class="noind">To apply this to our heterogeneous spheroid; if we put c<span class="su">1</span> for the
+semiaxis of that surface of equal density on which is situated the
+attracted point P, and c<span class="su">0</span> for the semiaxis of the outer surface, the
+attraction of that portion of the body which is exterior to P, namely,
+of all the shells which enclose P, has for components</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">X<span class="su">0</span> = <span class="spp">8</span>&frasl;<span class="suu">15</span>&pi;k²f <span class="f150">&int;</span><span class="sp1">c0</span><span class="su1">c1</span> &rho;</td> <td>de</td>
+<td rowspan="2">dc, &emsp; Z<span class="su">0</span> = <span class="spp">16</span>&frasl;<span class="suu">15</span>&pi;k²h <span class="f150">&int;</span><span class="sp1">c0</span><span class="su1">c1</span> &rho;</td> <td>de</td>
+<td rowspan="2">dc,</td></tr>
+<tr><td class="denom">dc</td> <td class="denom">dc</td></tr></table>
+
+<p><span class="pagenum"><a name="page805" id="page805"></a>805</span></p>
+
+<p class="noind">both e and &rho; being functions of c. Again the attraction of a homogeneous
+spheroid of density &rho; on an <i>external</i> point f, h has the
+components</p>
+
+<p class="center">X&Prime; = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²&rho;fr<span class="sp">&minus;3</span> {c³(1 + 2e) &minus; &lambda;ec<span class="sp">5</span>},</p>
+
+<p class="center">Z&Prime; = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²&rho;hr<span class="sp">&minus;3</span> {c³(1 + 2e) &minus; &lambda;&prime;ec<span class="sp">5</span>},</p>
+
+<p class="center">where &lambda; = <span class="spp">3</span>&frasl;<span class="suu">5</span>(4h² &minus; f²) / r<span class="sp">4</span>, &emsp; &lambda;&prime; = <span class="spp">3</span>&frasl;<span class="suu">5</span>(2h² &minus; 3f²) / r<span class="sp">4</span>, &emsp; and r² = f² + h².</p>
+
+<p class="noind">Now e being considered a function of c, we can at once express the
+attraction of a shell (density &rho;) contained between the surface defined
+by c + dc, e + de and that defined by c, e upon an external point; the
+differentials with respect to c, viz. dX&Prime; dZ&Prime;, must then be integrated
+with &rho; under the integral sign as being a function of c. The integration
+will extend from c = 0 to c = c<span class="su">1</span>. Thus the components of the
+attraction of the heterogeneous spheroid upon a particle within its
+mass, whose co-ordinates are f, 0, h, are</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">X = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²f <span class="f150">[</span></td> <td>1</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho; d{c³(1 + 2e)} &minus;</td> <td>&lambda;</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho; d(ec<span class="sp">5</span>) + <span class="spp">2</span>&frasl;<span class="suu">5</span>
+  <span class="f150">&int;</span><span class="sp1">c0</span><span class="su1">c1</span> &rho; de<span class="f150">]</span>,</td></tr>
+<tr><td class="denom">r<span class="sp">3</span></td> <td class="denom">r<span class="sp">3</span></td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">Z = &minus;<span class="spp">4</span>&frasl;<span class="suu">3</span>&pi;k²h <span class="f150">[</span></td> <td>1</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho; d{c³(1 + 2e)} &minus;</td> <td>&lambda;&prime;</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho; d(ec<span class="sp">5</span>) + <span class="spp">4</span>&frasl;<span class="suu">5</span>
+  <span class="f150">&int;</span><span class="sp1">c0</span><span class="su1">c1</span> &rho; de<span class="f150">]</span>.</td></tr>
+<tr><td class="denom">r<span class="sp">3</span></td> <td class="denom">r<span class="sp">3</span></td></tr></table>
+
+<p class="noind">We take into account the rotation of the earth by adding the centrifugal
+force f&omega;² = F to X. Now, the surface of constant density upon
+which the point f, 0, h is situated gives (1 &minus; 2e) fdf + hdh = 0; and the
+condition of equilibrium is that (X + F)df + Zdh = 0. Therefore,</p>
+
+<p class="center">(X + F) h = Zf (1 &minus; 2e),</p>
+
+<p class="noind">which, neglecting small quantities of the order e² and putting
+&omega;²t² = 4&pi;²k², gives</p>
+
+<table class="math0" summary="math">
+<tr><td>2e</td> <td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho;d{c³(1 + 2e)} &minus;</td>
+<td>6</td> <td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho;d(ec<span class="sp">5</span>) &minus;</td>
+<td>6</td> <td rowspan="2"><span class="f150">&int;</span><span class="sp1">c1</span><span class="su1">0</span> &rho;de =</td>
+<td>3&pi;</td> <td rowspan="2">.</td></tr>
+<tr><td class="denom">r³</td> <td class="denom">5r<span class="sp">5</span></td>
+<td class="denom">5</td> <td class="denom">t²</td></tr></table>
+
+<p class="noind">Here we must now put c for c<span class="su">1</span>, c for r; and 1 + 2e under the first
+integral sign may be replaced by unity, since small quantities of the
+second order are neglected. Two differentiations lead us to the
+following very important differential equation (Clairault):</p>
+
+<table class="math0" summary="math">
+<tr><td>d²e</td> <td rowspan="2">+</td>
+<td>2&rho;c²</td> <td rowspan="2">·</td>
+<td>de</td> <td rowspan="2">+ <span class="f150">(</span></td>
+<td>2&rho;c</td> <td rowspan="2">&minus;</td>
+<td>6</td> <td rowspan="2"><span class="f150">)</span> e = 0.</td></tr>
+<tr><td class="denom">dc²</td> <td class="denom">&int;&rho;c² dc</td>
+<td class="denom">dc</td> <td class="denom">&int;&rho;c² dc</td>
+<td class="denom">c²</td></tr></table>
+
+<p>When &rho; is expressed in terms of c, this equation can be integrated.
+We infer then that a rotating spheroid of very small ellipticity, composed
+of fluid homogeneous strata such as we have specified, will be
+in equilibrium; and when the law of the density is expressed, the
+law of the corresponding ellipticities will follow.</p>
+
+<p>If we put M for the mass of the spheroid, then</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M =</td> <td>4&pi;</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c</span><span class="su2">0</span> &rho;d{c³(1 + 2e)}; &emsp; and m =</td> <td>c³</td>
+<td rowspan="2">·</td> <td>4&pi;²</td>
+<td rowspan="2">,</td></tr>
+<tr><td class="denom">3</td> <td class="denom">M</td>
+<td class="denom">t²</td></tr></table>
+
+<p class="noind">and putting c = c<span class="su">0</span> in the equation expressing the condition of equilibrium,
+we find</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M(2e &minus; m) =</td> <td>4</td>
+<td rowspan="2">&pi; ·</td> <td>6</td>
+<td rowspan="2"><span class="f150">&int;</span><span class="sp1">c</span><span class="su2">0</span> &rho; d(ec<span class="sp">5</span>).</td></tr>
+<tr><td class="denom">3</td> <td class="denom">5c²</td></tr></table>
+
+<p class="noind">Making these substitutions in the expressions for the forces at the
+surface, and putting r/c = 1 + e &minus; e(h/c)², we get</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">G cos &phi; =</td> <td>Mk²</td>
+<td rowspan="2"><span class="f150">{</span>1 &minus; e &minus;</td> <td>3</td>
+<td rowspan="2">m + <span class="f150">(</span></td> <td>5</td>
+<td rowspan="2">m &minus; 2e<span class="f150">)</span></td> <td>h²</td>
+<td rowspan="2"><span class="f150">}</span></td> <td>f</td></tr>
+<tr><td class="denom">ac</td> <td class="denom">2</td>
+<td class="denom">2</td> <td class="denom">c²</td>
+<td class="denom">c</td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">G sin &phi; =</td> <td>Mk²</td>
+<td rowspan="2"><span class="f150">{</span>1 + e &minus;</td> <td>3</td>
+<td rowspan="2">m + <span class="f150">(</span></td> <td>5</td>
+<td rowspan="2">m &minus; 2e<span class="f150">)</span></td> <td>h²</td>
+<td rowspan="2"><span class="f150">}</span></td> <td>h</td> <td rowspan="2">.</td></tr>
+<tr><td class="denom">ac</td> <td class="denom">2</td>
+<td class="denom">2</td> <td class="denom">c²</td>
+<td class="denom">c</td></tr></table>
+
+<p class="noind">Here G is gravity in the latitude &phi;, and a the radius of the equator.
+Since</p>
+
+<p class="center">sec &phi; = (c/f){1 + e + (eh²/c²)},</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">G =</td> <td>Mk²</td>
+<td rowspan="2"><span class="f150">{</span>1 &minus;</td> <td>3</td>
+<td rowspan="2">m +<span class="f150">(</span></td> <td>5</td>
+<td rowspan="2">m &minus; e<span class="f150">)</span> sin² &phi;<span class="f150">}</span>,</td></tr>
+<tr><td class="denom">ac</td> <td class="denom">2</td>
+<td class="denom">2</td></tr></table>
+
+<p class="noind">an expression which contains the theorems we have referred to as
+discovered by Clairault.</p>
+
+<p>The theory of the figure of the earth as a rotating ellipsoid has
+been especially investigated by Laplace in his <i>Mécanique celeste</i>.
+The principal English works are:&mdash;Sir George Airy, <i>Mathematical
+Tracts</i>, a lucid treatment without the use of Laplace&rsquo;s coefficients;
+Archdeacon Pratt&rsquo;s <i>Attractions and Figure of the Earth</i>; and
+O&rsquo;Brien&rsquo;s <i>Mathematical Tracts</i>; in the last two Laplace&rsquo;s coefficients
+are used.</p>
+</div>
+
+<p>In 1845 Sir G.G. Stokes (<i>Camb. Trans.</i> viii.; see also <i>Camb.
+Dub. Math. Journ.</i>, 1849, iv.) proved that if the external form
+of the sea&mdash;imagined to percolate the land by canals&mdash;be a
+spheroid with small ellipticity, then the law of gravity is that
+which we have shown above; his proof required no assumption
+as to the ellipticity of the internal strata, or as to the past or
+present fluidity of the earth. This investigation admits of being
+regarded conversely, viz. as determining the elliptical form of
+the earth from measurements of gravity; if G, the observed
+value of gravity in latitude &phi;, be expressed in the form
+G = g(1 + &beta; sin² &phi;), where g is the value at the equator and &beta;
+a coefficient. In this investigation, the square and higher powers
+of the ellipticity are neglected; the solution was completed
+by F.R. Helmert with regard to the square of the ellipticity,
+who showed that a term with sin² 2&phi; appeared (see Helmert,
+<i>Geodäsie</i>, ii. 83). For the coefficient of this term, the gravity
+measurements give a small but not sufficiently certain value;
+we therefore assume a value which agrees best with the hypothesis
+of the fluid state of the entire earth; this assumption is well
+supported, since even at a depth of only 50 km. the pressure of
+the superincumbent crust is so great that rocks become plastic,
+and behave approximately as fluids, and consequently the crust
+of the earth floats, to some extent, on the interior (even though
+this may not be fluid in the usual sense of the word). This is
+the geological theory of &ldquo;Isostasis&rdquo; (cf. <span class="sc"><a href="#artlinks">Geology</a></span>); it agrees
+with the results of measurements of gravity (<i>vide infra</i>), and was
+brought forward in the middle of the 19th century by J.H.
+Pratt, who deduced it from observations made in India.</p>
+
+<p>The sin² 2&phi; term in the expression for G, and the corresponding
+deviation of the meridian from an ellipse, have been analytically
+established by Sir G.H. Darwin and E. Wiechert; earlier and
+less complete investigations were made by Sir G.B. Airy and
+O. Callandreau. In consequence of the sin² 2&phi; term, two parameters
+of the level surfaces in the interior of the earth are to be
+determined; for this purpose, Darwin develops two differential
+equations in the place of the one by Clairault. By assuming
+Roche&rsquo;s law for the variation of the density in the interior of the
+Earth, viz. &rho; = &rho;<span class="su">1</span> &minus; k(c/c<span class="su">1</span>)², k being a coefficient, it is shown that
+in latitude 45°, the meridian is depressed about 3¼ metres from
+the ellipse, and the coefficient of the term sin²&phi; cos²&phi; (= ¼ sin²2&phi;)
+is &minus;0.0000295. According to Wiechert the earth is composed
+of a kernel and a shell, the kernel being composed of material,
+chiefly metallic iron, of density near 8.2, and the shell, about
+900 miles thick, of silicates, &amp;c., of density about 3.2. On this
+assumption the depression in latitude 45° is 2¾ metres, and the
+coefficient of sin²&phi; cos²&phi; is, in round numbers, &minus;0.0000280.<a name="fa2c" id="fa2c" href="#ft2c"><span class="sp">2</span></a>
+To this additional term in the formula for G, there corresponds
+an extension of Clairault&rsquo;s formula for the calculation of the
+flattening from &beta; with terms of the higher orders; this was first
+accomplished by Helmert.</p>
+
+<p>For a long time the assumption of an ellipsoid with three
+unequal axes has been held possible for the figure of the earth, in
+consequence of an important theorem due to K.G. Jacobi, who
+proved that for a homogeneous fluid in rotation a spheroid is not
+the only form of equilibrium; an ellipsoid rotating round its
+least axis may with certain proportions of the axes and a certain
+time of revolution be a form of equilibrium.<a name="fa3c" id="fa3c" href="#ft3c"><span class="sp">3</span></a> It has been objected
+to the figure of three unequal axes that it does not satisfy, in
+the proportions of the axes, the conditions brought out in
+Jacobi&rsquo;s theorem (c : a &lt; 1/&radic;2). Admitting this, it has to be
+noted, on the other hand, that Jacobi&rsquo;s theorem contemplates a
+homogeneous fluid, and this is certainly far from the actual
+condition of our globe; indeed the irregular distribution of
+continents and oceans suggests the possibility of a sensible
+divergence from a perfect surface of revolution. We may,
+however, assume the ellipsoid with three unequal axes to be an
+interpolation form. More plausible forms are little adapted for
+computation.<a name="fa4c" id="fa4c" href="#ft4c"><span class="sp">4</span></a> Consequently we now generally take the ellipsoid
+of rotation as a basis, especially so because measurements of
+gravity have shown that the deviation from it is but trifling.</p>
+
+<p class="pt2 center"><i>Local Attraction.</i></p>
+
+<p>In speaking of the figure of the earth, we mean the surface
+of the sea imagined to percolate the continents by canals. That
+<span class="pagenum"><a name="page806" id="page806"></a>806</span>
+this surface should turn out, after precise measurements, to be
+exactly an ellipsoid of revolution is <i>a priori</i> improbable. Although
+it may be highly probable that originally the earth was
+a fluid mass, yet in the cooling whereby the present crust has
+resulted, the actual solid surface has been left most irregular
+in form. It is clear that these irregularities of the visible surface
+must be accompanied by irregularities in the mathematical
+figure of the earth, and when we consider the general surface
+of our globe, its irregular distribution of mountain masses,
+continents, with oceans and islands, we are prepared to admit
+that the earth may not be precisely any surface of revolution.
+Nevertheless, there must exist some spheroid which agrees very
+closely with the mathematical figure of the earth, and has the
+same axis of rotation. We must conceive this figure as exhibiting
+slight departures from the spheroid, the two surfaces cutting
+one another in various lines; thus a point of the surface is
+defined by its latitude, longitude, and its height above the
+&ldquo;spheroid of reference.&rdquo; Calling this height N, then of the
+actual magnitude of this quantity we can generally have no
+information, it only obtrudes itself on our notice by its variations.
+In the vicinity of mountains it may change sign in the space
+of a few miles; N being regarded as a function of the latitude
+and longitude, if its differential coefficient with respect to the
+former be zero at a certain point, the normals to the two surfaces
+then will lie in the prime vertical; if the differential coefficient
+of N with respect to the longitude be zero, the two normals will
+lie in the meridian; if both coefficients are zero, the normals
+will coincide. The comparisons of terrestrial measurements with
+the corresponding astronomical observations have always been
+accompanied with discrepancies. Suppose A and B to be two
+trigonometrical stations, and that at A there is a disturbing force
+drawing the vertical through an angle &delta;, then it is evident that
+the apparent zenith of A will be really that of some other place
+A&prime;, whose distance from A is r&delta;, when r is the earth&rsquo;s radius;
+and similarly if there be a disturbance at B of the amount &delta;&prime;,
+the apparent zenith of B will be really that of some other place
+B&prime;, whose distance from B is r&delta;&prime;. Hence we have the discrepancy
+that, while the geodetic measurements deal with the points
+A and B, the astronomical observations belong to the points
+A&prime;, B&prime;. Should &delta;, &delta;&prime; be equal and parallel, the displacements
+AA&prime;, BB&prime; will be equal and parallel, and no discrepancy will
+appear. The non-recognition of this circumstance often led
+to much perplexity in the early history of geodesy. Suppose
+that, through the unknown variations of N, the probable error
+of an observed latitude (that is, the angle between the normal
+to the mathematical surface of the earth at the given point
+and that of the corresponding point on the spheroid of reference)
+be &epsilon;, then if we compare two arcs of a degree each in mean
+latitudes, and near each other, say about five degrees of latitude
+apart, the probable error of the resulting value of the ellipticity
+will be approximately ±<span class="spp">1</span>&frasl;<span class="suu">500</span>&epsilon;, &epsilon; being expressed in seconds,
+so that if &epsilon; be so great as 2&Prime; the probable error of the resulting
+ellipticity will be greater than the ellipticity itself.</p>
+
+<p>It is necessary at times to calculate the attraction of a
+mountain, and the consequent disturbance of the astronomical
+zenith, at any point within its influence. The deflection of the
+plumb-line, caused by a local attraction whose amount is k²A&delta;,
+is measured by the ratio of k²A&delta; to the force of gravity at the
+station. Expressed in seconds, the deflection &Lambda; is</p>
+
+<p class="center">&Lambda; = 12&Prime;.447A&delta; / &rho;,</p>
+
+<p class="noind">where &rho; is the mean density of the earth, &delta; that of the attracting
+mass, and A = &fnof;s<span class="sp">&minus;3</span>xdv, in which dv is a volume element of the
+attracting mass within the distance s from the point of deflection,
+and x the projection of s on the horizontal plane through this
+point, the linear unit in expressing A being a mile. Suppose,
+for instance, a table-land whose form is a rectangle of 12 miles by
+8 miles, having a height of 500 ft. and density half that of the
+earth; let the observer be 2 miles distant from the middle
+point of the longer side. The deflection then is 1&Prime;.472; but at
+1 mile it increases to 2&Prime;.20.</p>
+
+<p>At sixteen astronomical stations in the English survey the
+disturbance of latitude due to the form of the ground has been
+computed, and the following will give an idea of the results.
+At six stations the deflection is under 2&Prime;, at six others it is
+between 2&Prime; and 4&Prime;, and at four stations it exceeds 4&Prime;. There is
+one very exceptional station on the north coast of Banffshire,
+near the village of Portsoy, at which the deflection amounts
+to 10&Prime;, so that if that village were placed on a map in a position
+to correspond with its astronomical latitude, it would be 1000 ft.
+out of position! There is the sea to the north and an undulating
+country to the south, which, however, to a spectator at the
+station does not suggest any great disturbance of gravity. A
+somewhat rough estimate of the local attraction from external
+causes gives a maximum limit of 5&Prime;, therefore we have 5&Prime; which
+must arise from unequal density in the underlying strata in the
+surrounding country. In order to throw light on this remarkable
+phenomenon, the latitudes of a number of stations between
+Nairn on the west, Fraserburgh on the east, and the Grampians
+on the south, were observed, and the local deflections determined.
+It is somewhat singular that the deflections diminish in all
+directions, not <i>very</i> regularly certainly, and most slowly in a south-west
+direction, finally disappearing, and leaving the maximum
+at the original station at Portsoy.</p>
+
+<p>The method employed by Dr C. Hutton for computing the
+attraction of masses of ground is so simple and effectual that it
+can hardly be improved on. Let a horizontal plane pass through
+the given station; let r, &theta; be the polar co-ordinates of any point
+in this plane, and r, &theta;, z, the co-ordinates of a particle of the
+attracting mass; and let it be required to find the attraction of
+a portion of the mass contained between the horizontal planes
+z = 0, z = h, the cylindrical surfaces r = r<span class="su">1</span>, r = r<span class="su">2</span>, and the vertical
+planes &theta; = &theta;<span class="su">1</span>, &theta; = &theta;<span class="su">2</span>. The component of the attraction at the
+station or origin along the line &theta; = 0 is</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">k²&delta; <span class="f150">&int;</span><span class="sp1">r2</span><span class="su1">r1</span>
+ <span class="f150">&int;</span><span class="sp1">&theta;2</span><span class="su1">&theta;1</span>
+ <span class="f150">&int;</span><span class="sp1">h</span><span class="su2">0</span></td> <td>r²cos&theta;</td>
+<td rowspan="2">dr d&theta; dz =
+ k²&delta;h (sin&theta;<span class="su">2</span> &minus; sin&theta;<span class="su">1</span>) log{r<span class="su">2</span> + (r<span class="su">2</span>² + h²)<span class="sp">1/2</span> / r<span class="su">1</span> + (r<span class="su">1</span>² + h²)<span class="sp">1/2</span>}.</td></tr>
+<tr><td class="denom">(r² + z²)<span class="sp">3/2</span></td></tr></table>
+
+<p class="noind">By taking r<span class="su">2</span> &minus; r<span class="su">1</span>, sufficiently small, and supposing h also small
+compared with r<span class="su">1</span> + r<span class="su">2</span> (as it usually is), the attraction is</p>
+
+<p class="center">k²&delta; (r<span class="su">2</span> &minus; r<span class="su">1</span>) (sin&theta;<span class="su">2</span> &minus; sin&theta;<span class="su">1</span>) h/r,</p>
+
+<p class="noind">where r = ½ (r<span class="su">1</span> + r<span class="su">2</span>). This form suggests the following procedure.
+Draw on the contoured map a series of equidistant circles,
+concentric with the station, intersected by radial lines so disposed
+that the sines of their azimuths are in arithmetical progression.
+Then, having estimated from the map the mean heights of the
+various compartments, the calculation is obvious.</p>
+
+<p>In mountainous countries, as near the Alps and in the Caucasus,
+deflections have been observed to the amount of as much as
+30&Prime;, while in the Himalayas deflections amounting to 60&Prime; were
+observed. On the other hand, deflections have been observed
+in flat countries, such as that noted by Professor K.G. Schweizer,
+who has shown that, at certain stations in the vicinity of Moscow,
+within a distance of 16 miles the plumb-line varies 16&Prime; in such a
+manner as to indicate a vast deficiency of matter in the underlying
+strata; deflections of 10&Prime; were observed in the level regions of
+north Germany.</p>
+
+<p>Since the attraction of a mountain mass is expressed as a
+numerical multiple of &delta; : &rho; the ratio of the density of the mountain
+to that of the earth, if we have any independent means of
+ascertaining the amount of the deflection, we have at once the
+ratio &rho; : &delta;, and thus we obtain the mean density of the earth,
+as, for instance, at Schiehallion, and afterwards at Arthur&rsquo;s
+Seat. Experiments of this kind for determining the mean
+density of the earth have been made in greater numbers; but
+they are not free from objection (see <span class="sc"><a href="#artlinks">Gravitation</a></span>).</p>
+
+<p>Let us now consider the perturbation attending a spherical
+subterranean mass. A compact mass of great density at a small
+distance under the surface of the earth will produce an elevation
+of the mathematical surface which is expressed by the formula</p>
+
+<p class="center">y = a&mu; {(1 &minus; 2u cos&theta; + u²)<span class="sp">&minus;1/2</span> &minus; 1},</p>
+
+<p class="noind">where a is the radius of the (spherical) earth, a (1 &minus; u) the distance
+<span class="pagenum"><a name="page807" id="page807"></a>807</span>
+of the disturbing mass below the surface, &mu; the ratio of the disturbing
+mass to the mass of the earth, and a&theta; the distance of any
+point on the surface from that point, say Q, which is vertically
+over the disturbing mass. The maximum value of y is at Q,
+where it is y = a&mu;u (1 &minus; u). The deflection at the distance a&theta;
+is &Lambda; = &mu;u sin&theta; (1 &minus; 2u cos&theta; + u²)<span class="sp">&minus;3/2</span>, or since &theta; is small, putting
+h + u = 1, we have &Lambda; = &mu;&theta; (h² + &theta;²)<span class="sp">&minus;3/2</span>. The maximum deflection
+takes place at a point whose distance from Q is to the
+depth of the mass as 1 : &radic;2, and its amount is 2&mu;/3 &radic;<span class="ov">3h²</span>.
+If, for instance, the disturbing mass were a sphere a mile
+in diameter, the excess of its density above that of the surrounding
+country being equal to half the density of the
+earth, and the depth of its centre half a mile, the greatest deflection
+would be 5&Prime;, and the greatest value of y only two inches.
+Thus a large disturbance of gravity may arise from an irregularity
+in the mathematical surface whose actual magnitude, as regards
+height at least, is extremely small.</p>
+
+<p>The effect of the disturbing mass &mu; on the vibrations of a
+pendulum would be a maximum at Q; if v be the number of
+seconds of time gained per diem by the pendulum at Q, and &sigma;
+the number of seconds of angle in the maximum deflection, then
+it may be shown that v/&sigma; = &pi;&radic;<span class="ov">3</span>/10.</p>
+
+<p>The great Indian survey, and the attendant measurements of
+the degree of latitude, gave occasion to elaborate investigations
+of the deflection of the plumb-line in the neighbourhood of the
+high plateaus and mountain chains of Central Asia. Archdeacon
+Pratt (<i>Phil. Trans.</i>, 1855 and 1857), in instituting these investigations,
+took into consideration the influence of the apparent
+diminution of the mass of the earth&rsquo;s crust occasioned by the
+neighbouring ocean-basins; he concluded that the accumulated
+masses of mountain chains, &amp;c., corresponded to subterranean
+mass diminutions, so that over any level surface in a fixed depth
+(perhaps 100 miles or more) the masses of prisms of equal section
+are equal. This is supported by the gravity measurements at
+Moré in the Himalayas at a height of 4696 metres, which showed
+no deflection due to the mountain chain (<i>Phil. Trans.</i>, 1871);
+more recently, H.A. Faye (<i>Compt. rend.</i>, 1880) arrived at the
+same conclusion for the entire continent.</p>
+
+<p>This compensation, however, must only be regarded as a general
+principle; in certain cases, the compensating masses show marked
+horizontal displacements. Further investigations, especially of
+gravity measurements, will undoubtedly establish other important
+facts. Colonel S.G. Burrard has recently recalculated,
+with the aid of more exact data, certain Indian deviations
+of the plumb-line, and has established that in the region
+south of the Himalayas (lat. 24°) there is a subterranean perturbing
+mass. The extent of the compensation of the high
+mountain chains is difficult to recognize from the latitude
+observations, since the same effect may result from different
+causes; on the other hand, observations of geographical longitude
+have established a strong compensation.<a name="fa5c" id="fa5c" href="#ft5c"><span class="sp">5</span></a></p>
+
+<p class="pt2 center"><i>Meridian Arcs.</i></p>
+
+<p>The astronomical stations for the measurement of the degree
+of latitude will generally lie not exactly on the same meridian;
+and it is therefore necessary to calculate the arcs of meridian
+M which lie between the latitude of neighbouring stations. If
+S be the geodetic line calculated from the triangulation with the
+astronomically determined azimuths &alpha;<span class="su">1</span> and &alpha;<span class="su">2</span>, then</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M = S</td> <td>cos &alpha;</td>
+<td rowspan="2"><span class="f150">{</span>1 + <span class="spp">1</span>&frasl;<span class="suu">12</span></td> <td>S²</td>
+<td rowspan="2">sin²&alpha; ...<span class="f150">}</span>,</td></tr>
+<tr><td class="denom">cos ½&Delta;&alpha;</td> <td class="denom">&alpha;²</td></tr></table>
+
+<p class="noind">in which 2&alpha; = &alpha;<span class="su">1</span> + &alpha;<span class="su">2</span> &minus; 180°, &Delta;&alpha; = &alpha;<span class="su">2</span> &minus; &alpha;<span class="su">1</span> &minus; 180°.</p>
+
+<p>The length of the arc of meridian between the latitudes &phi;<span class="su">1</span>
+and &phi;<span class="su">2</span> is</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M = <span class="f150">&int;</span><span class="sp1">&phi;2</span><span class="su1">&phi;1</span>
+ &rho;d&phi; = &alpha; <span class="f150">&int;</span><span class="sp1">&phi;2</span><span class="su1">&phi;1</span></td> <td>(1 &minus; e²) d&phi;</td></tr>
+<tr><td class="denom">(1 &minus; e² sin²&phi;)<span class="sp">3/2</span></td></tr></table>
+
+<p class="noind">where a²e² = a² &minus; b²; instead of using the eccentricity e, put the
+ratio of the axes b : a = 1 &minus; n : 1 + n, then</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M = <span class="f150">&int;</span><span class="sp1">&phi;2</span><span class="su1">&phi;1</span></td> <td>b (1 + n) (1 &minus; n²) d&phi;</td>
+<td rowspan="2">.</td></tr>
+<tr><td class="denom">(1 + 2n cos2&phi; + n²)<span class="sp">3/2</span></td></tr></table>
+
+<p class="noind">This, after integration, gives</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M/b = <span class="f150">(</span>1 + n +</td> <td>5</td>
+<td rowspan="2">n²  +</td> <td>5</td>
+<td rowspan="2">n³<span class="f150">)</span>&alpha;<span class="su">0</span> &minus; <span class="f150">(</span>3n +  3n² +</td> <td>21</td>
+<td rowspan="2">n³<span class="f150">)</span>&alpha;<span class="su">1</span> + <span class="f150">(</span></td> <td>15</td>
+<td rowspan="2">n² +</td> <td>15</td>
+<td rowspan="2">n³<span class="f150">)</span>&alpha;<span class="su">2</span> &minus; <span class="f150">(</span></td> <td>35</td>
+<td rowspan="2">n³<span class="f150">)</span>&alpha;<span class="su">3</span>,</td></tr>
+<tr><td class="denom">4</td> <td class="denom">4</td>
+<td class="denom">8</td> <td class="denom">8</td>
+<td class="denom">8</td> <td class="denom">24</td></tr></table>
+
+<p class="noind">where</p>
+
+<table class="reg" summary="poem"><tr><td> <div class="poemr">
+<p>&alpha;<span class="su">0</span> = &phi;<span class="su">2</span> &minus; &phi;<span class="su">1</span></p>
+<p>&alpha;<span class="su">1</span> = sin (&phi;<span class="su">2</span> &minus; &phi;<span class="su">1</span>) cos (&phi;<span class="su">2</span> + &phi;<span class="su">1</span>)</p>
+<p>&alpha;<span class="su">2</span> = sin 2(&phi;<span class="su">2</span> &minus; &phi;<span class="su">1</span>) cos 2(&phi;<span class="su">2</span> + &phi;<span class="su">1</span>)</p>
+<p>&alpha;<span class="su">3</span> = sin 3(&phi;<span class="su">2</span> &minus; &phi;<span class="su">1</span>) cos 3(&phi;<span class="su">2</span> + &phi;<span class="su">1</span>).</p>
+</div> </td></tr></table>
+
+<p class="noind">The part of M which depends on n³ is very small; in fact, if we
+calculate it for one of the longest arcs measured, the Russian arc,
+it amounts to only an inch and a half, therefore we omit this
+term, and put for M/b the value</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2"><span class="f150">(</span>1 + n +</td> <td>5</td>
+<td rowspan="2">n²<span class="f150">)</span>&alpha;<span class="su">0</span> &minus; <span class="f150">(</span>3n + 3n²<span class="f150">)</span>&alpha;<span class="su">1</span> + <span class="f150">(</span></td> <td>15</td>
+<td rowspan="2">n²<span class="f150">)</span>&alpha;<span class="su">2</span>.</td></tr>
+<tr><td class="denom">4</td> <td class="denom">8</td></tr></table>
+
+<p class="noind">Now, if we suppose the observed latitudes to be affected with
+errors, and that the true latitudes are &phi;<span class="su">1</span> + x<span class="su">1</span>, &phi;<span class="su">2</span> + x<span class="su">2</span>; and if
+further we suppose that n<span class="su">1</span> + dn is the true value of a &minus; b : a + b,
+and that n<span class="su">1</span> itself is merely a very approximate numerical value,
+we get, on making these substitutions and neglecting the influence
+of the corrections x on the <i>position</i> of the arc in latitude, <i>i.e.</i> on
+&phi;<span class="su">1</span> + &phi;<span class="su">2</span>,</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">M/b = <span class="f150">(</span>1 + n<span class="su">1</span> +</td> <td>5</td>
+<td rowspan="2">n<span class="su">1</span>²<span class="f150">)</span>&alpha;<span class="su">0</span> &minus; <span class="f150">(</span>3n<span class="su">1</span> + 3n<span class="su">1</span>²<span class="f150">)</span>&alpha;<span class="su">1</span> + <span class="f150">(</span></td> <td>15</td>
+<td rowspan="2">n<span class="su">1</span>²<span class="f150">)</span>&alpha;<span class="su">2</span> + <span class="f150">{</span> <span class="f150">(</span>1 +</td> <td>5</td>
+<td rowspan="2">n<span class="su">1</span><span class="f150">)</span>&alpha;<span class="su">0</span> &minus; <span class="f150">(</span>3 + 6n<span class="su">1</span><span class="f150">)</span>&alpha;<span class="su">1</span> + <span class="f150">(</span></td> <td>15</td>
+<td rowspan="2">n<span class="su">1</span><span class="f150">)</span>&alpha;<span class="su">2</span> <span class="f150">}</span>dn</td></tr>
+<tr><td class="denom">4</td> <td class="denom">8</td>
+<td class="denom">2</td> <td class="denom">4</td></tr></table>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">+ <span class="f150">{</span>1 + n<span class="su">1</span> &minus; 3n</td> <td>d&alpha;<span class="su">1</span></td>
+<td rowspan="2"><span class="f150">}</span>d&alpha;<span class="su">0</span>;</td></tr>
+<tr><td class="denom">d&alpha;<span class="su">0</span></td></tr></table>
+
+<p class="noind">here d&alpha;<span class="su">0</span> = x<span class="su">2</span> &minus; x<span class="su">1</span>; and as b is only known approximately, put
+b = b<span class="su">1</span>(1 + u); then we get, after dividing through by the coefficient
+of d&alpha;<span class="su">0</span>, which is = 1 + n<span class="su">1</span> &minus; 3n<span class="su">1</span> cos(&phi;<span class="su">2</span> &minus; &phi;<span class="su">1</span>) cos(&phi;<span class="su">2</span> + &phi;<span class="su">1</span>),
+an equation of the form x<span class="su">2</span> = x<span class="su">1</span> + h + fu + gv, where for convenience
+we put v for dn.</p>
+
+<p>Now in every measured arc there are not only the extreme
+stations determined in latitude, but also a number of intermediate
+stations so that if there be i + 1 stations there will be
+i equations</p>
+
+<table class="reg" summary="poem"><tr><td> <div class="poemr">
+<p>x<span class="su">2</span> = x<span class="su">1</span> + f<span class="su">1</span>u + g<span class="su">1</span>v + h<span class="su">1</span></p>
+<p>x<span class="su">3</span> = x<span class="su">1</span> + f<span class="su">2</span>u + g<span class="su">2</span>v + h<span class="su">2</span></p>
+<p>&emsp; : &emsp; : &emsp;&emsp;&emsp;&emsp; :</p>
+<p>&emsp; : &emsp; : &emsp;&emsp;&emsp;&emsp; :</p>
+<p>x<span class="su">i</span> = x<span class="su">1</span> + f<span class="su">i</span>u + g<span class="su">i</span>v + h<span class="su">i</span></p>
+</div> </td></tr></table>
+
+<p>In combining a number of different arcs of meridian, with
+the view of determining the figure of the earth, each arc will
+supply a number of equations in u and v and the corrections to
+its observed latitudes. Then, according to the method of least
+squares, those values of u and v are the most probable which
+render the sum of the squares of <i>all</i> the errors x a minimum.
+The corrections x which are here applied arise not from errors
+of observation only. The mere uncertainty of a latitude, as
+determined with modern instruments, does not exceed a very
+small fraction of a second as far as errors of observation go, but
+no accuracy in observing will remove the error that may arise
+from local attraction. This, as we have seen, may amount to
+some seconds, so that the corrections x to the observed latitudes
+are attributable to local attraction. Archdeacon Pratt objected
+to this mode of applying least squares first used by Bessel; but
+Bessel was right, and the objection is groundless. Bessel found,
+in 1841, from ten meridian arcs with a total amplitude of 50°.6:</p>
+
+<table class="reg" summary="poem"><tr><td> <div class="poemr">
+<p>a = 3272077 toises = 6377397 metres.</p>
+<p>e (ellipticity) = (a &minus; b) / a &asymp; 1/299.15 (prob. error ± 3.2).</p>
+</div> </td></tr></table>
+
+<p class="noind">The probable error in the length of the earth&rsquo;s quadrant is
+± 336 m.</p>
+
+<p>We now give a series of some meridian-arcs measurements,
+which were utilized in 1866 by A.R. Clarke in the <i>Comparisons
+of the Standards of Length</i>, pp. 280-287; details of the calculations
+are given by the same author in his <i>Geodesy</i> (1880), pp.
+311 et seq.</p>
+
+<p>The data of the French arc from Formentera to Dunkirk are&mdash;</p>
+
+<p><span class="pagenum"><a name="page808" id="page808"></a>808</span></p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcc">Stations.</td> <td class="tccm" colspan="3">Astronomical<br />Latitudes.</td> <td class="tccm">Distance of<br />Parallels.</td></tr>
+
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">Formentera</td> <td class="tcc">38</td> <td class="tcc">39</td> <td class="tcc">53.17</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Mountjouy</td> <td class="tcc">41</td> <td class="tcc">21</td> <td class="tcc">44.96</td> <td class="tcr">982671.04</td></tr>
+<tr><td class="tcl">Barcelona</td> <td class="tcc">41</td> <td class="tcc">22</td> <td class="tcc">47.90</td> <td class="tcr">988701.92</td></tr>
+<tr><td class="tcl">Carcassonne</td> <td class="tcc">43</td> <td class="tcc">12</td> <td class="tcc">54.30</td> <td class="tcr">1657287.93</td></tr>
+<tr><td class="tcl">Pantheon</td> <td class="tcc">48</td> <td class="tcc">50</td> <td class="tcc">47.98</td> <td class="tcr">3710827.13</td></tr>
+<tr><td class="tcl">Dunkirk</td> <td class="tcc">51</td> <td class="tcc">&ensp;2</td> <td class="tcc">&ensp;8.41</td> <td class="tcr">4509790.84</td></tr>
+</table>
+
+<p>The distance of the parallels of Dunkirk and Greenwich,
+deduced from the extension of the triangulation of England
+into France, in 1862, is 161407.3 ft., which is 3.9 ft. greater than
+that obtained from Captain Kater&rsquo;s triangulation, and 3.2 ft.
+less than the distance calculated by Delambre from General Roy&rsquo;s
+triangulation. The following table shows the data of the
+English arc with the distances in standard feet from Formentera.</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">Formentera</td> <td class="tcc" colspan="3">· ·</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Greenwich</td> <td class="tcc">51</td> <td class="tcc">28</td> <td class="tcc">38.30</td> <td class="tcc">4671198.3</td></tr>
+<tr><td class="tcl">Arbury</td> <td class="tcc">52</td> <td class="tcc">13</td> <td class="tcc">26.59</td> <td class="tcc">4943837.6</td></tr>
+<tr><td class="tcl">Clifton</td> <td class="tcc">53</td> <td class="tcc">27</td> <td class="tcc">29.50</td> <td class="tcc">5394063.4</td></tr>
+<tr><td class="tcl">Kellie Law</td> <td class="tcc">56</td> <td class="tcc">14</td> <td class="tcc">53.60</td> <td class="tcc">6413221.7</td></tr>
+<tr><td class="tcl">Stirling</td> <td class="tcc">57</td> <td class="tcc">27</td> <td class="tcc">49.12</td> <td class="tcc">6857323.3</td></tr>
+<tr><td class="tcl">Saxavord</td> <td class="tcc">60</td> <td class="tcc">49</td> <td class="tcc">37.21</td> <td class="tcc">8086820.7</td></tr>
+</table>
+
+<p>The latitude assigned in this table to Saxavord is not the
+directly observed latitude, which is 60° 49&prime; 38.58&Prime;, for there
+are here a cluster of three points, whose latitudes are astronomically
+determined; and if we transfer, by means of the geodesic
+connexion, the latitude of Gerth of Scaw to Saxavord, we get
+60° 49&prime; 36.59&Prime;; and if we similarly transfer the latitude of Balta,
+we get 60° 49&prime; 36.46&Prime;. The mean of these three is that entered
+in the above table.</p>
+
+<p>For the Indian arc in long. 77° 40&prime; we have the following
+data:&mdash;</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">Punnea</td> <td class="tcr">8</td> <td class="tcr">9</td> <td class="tcc">31.132</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Putchapolliam</td> <td class="tcr">10</td> <td class="tcr">59</td> <td class="tcc">42.276</td> <td class="tcc">1029174.9</td></tr>
+<tr><td class="tcl">Dodagunta</td> <td class="tcr">12</td> <td class="tcr">59</td> <td class="tcc">52.165</td> <td class="tcc">1756562.0</td></tr>
+<tr><td class="tcl">Namthabad</td> <td class="tcr">15</td> <td class="tcr">5</td> <td class="tcc">53.562</td> <td class="tcc">2518376.3</td></tr>
+<tr><td class="tcl">Daumergida</td> <td class="tcr">18</td> <td class="tcr">3</td> <td class="tcc">15.292</td> <td class="tcc">3591788.4</td></tr>
+<tr><td class="tcl">Takalkhera</td> <td class="tcr">21</td> <td class="tcr">5</td> <td class="tcc">51.532</td> <td class="tcc">4697329.5</td></tr>
+<tr><td class="tcl">Kalianpur</td> <td class="tcr">24</td> <td class="tcr">7</td> <td class="tcc">11.262</td> <td class="tcc">5794695.7</td></tr>
+<tr><td class="tcl">Kaliana</td> <td class="tcr">29</td> <td class="tcr">30</td> <td class="tcc">48.322</td> <td class="tcc">7755835.9</td></tr>
+</table>
+
+<p>The data of the Russian arc (long. 26° 40&prime;) taken from Struve&rsquo;s
+work are as below:&mdash;</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">Staro Nekrasovsk</td> <td class="tcr">45</td> <td class="tcr">20</td> <td class="tcr">2.94</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Vodu-Luy</td> <td class="tcr">47</td> <td class="tcr">1</td> <td class="tcr">24.98</td> <td class="tcr">616529.81</td></tr>
+<tr><td class="tcl">Suprunkovzy</td> <td class="tcr">48</td> <td class="tcr">45</td> <td class="tcr">3.04</td> <td class="tcr">1246762.17</td></tr>
+<tr><td class="tcl">Kremenets</td> <td class="tcr">50</td> <td class="tcr">5</td> <td class="tcr">49.95</td> <td class="tcr">1737551.48</td></tr>
+<tr><td class="tcl">Byelin</td> <td class="tcr">52</td> <td class="tcr">2</td> <td class="tcr">42.16</td> <td class="tcr">2448745.17</td></tr>
+<tr><td class="tcl">Nemesh</td> <td class="tcr">54</td> <td class="tcr">39</td> <td class="tcr">4.16</td> <td class="tcr">3400312.63</td></tr>
+<tr><td class="tcl">Jacobstadt</td> <td class="tcr">56</td> <td class="tcr">30</td> <td class="tcr">4.97</td> <td class="tcr">4076412.28</td></tr>
+<tr><td class="tcl">Dorpat</td> <td class="tcr">58</td> <td class="tcr">22</td> <td class="tcr">47.56</td> <td class="tcr">4762421.43</td></tr>
+<tr><td class="tcl">Hogland</td> <td class="tcr">60</td> <td class="tcr">5</td> <td class="tcr">9.84</td> <td class="tcr">5386135.39</td></tr>
+<tr><td class="tcl">Kilpi-maki</td> <td class="tcr">62</td> <td class="tcr">38</td> <td class="tcr">5.25</td> <td class="tcr">6317905.67</td></tr>
+<tr><td class="tcl">Torneå</td> <td class="tcr">65</td> <td class="tcr">49</td> <td class="tcr">44.57</td> <td class="tcr">7486789.97</td></tr>
+<tr><td class="tcl">Stuor-oivi</td> <td class="tcr">68</td> <td class="tcr">40</td> <td class="tcr">58.40</td> <td class="tcr">8530517.90</td></tr>
+<tr><td class="tcl">Fuglenaes</td> <td class="tcr">70</td> <td class="tcr">40</td> <td class="tcr">11.23</td> <td class="tcr">9257921.06</td></tr>
+</table>
+
+<p class="noind">From the are measured in Cape Colony by Sir Thomas Maclear
+in long. 18° 30&prime;, we have</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">North End</td> <td class="tcr">29</td> <td class="tcr">44</td> <td class="tcr">17.66</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Heerenlogement Berg</td> <td class="tcr">31</td> <td class="tcr">58</td> <td class="tcr">9.11</td> <td class="tcr">811507.7</td></tr>
+<tr><td class="tcl">Royal Observatory</td> <td class="tcr">33</td> <td class="tcr">56</td> <td class="tcr">3.20</td> <td class="tcr">1526386.8</td></tr>
+<tr><td class="tcl">Zwart Kop</td> <td class="tcr">34</td> <td class="tcr">13</td> <td class="tcr">32.13</td> <td class="tcr">1632583.3</td></tr>
+<tr><td class="tcl">Cape Point</td> <td class="tcr">34</td> <td class="tcr">21</td> <td class="tcr">6.26</td> <td class="tcr">1678375.7</td></tr>
+</table>
+
+<p class="noind">And, finally, for the Peruvian arc, in long. 281° 0&prime;,</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td> <td class="tcc">Ft.</td></tr>
+<tr><td class="tcl">Tarqui</td> <td class="tcc">3</td> <td class="tcc">4</td> <td class="tcc">32.068</td> <td class="tcc">· ·</td></tr>
+<tr><td class="tcl">Cotchesqui</td> <td class="tcc">0</td> <td class="tcc">2</td> <td class="tcc">31.387</td> <td class="tcc">1131036.3</td></tr>
+</table>
+
+<p>Having now stated the data of the problem, we may seek that
+oblate ellipsoid (spheroid) which best represents the observations.
+Whatever the real figure may be, it is certain that if we suppose
+it an ellipsoid with three unequal axes, the arithmetical process
+will bring out an ellipsoid, which will agree better with all
+the observed latitudes than any spheroid would, therefore we
+do not <i>prove</i> that it is an ellipsoid; to prove this, arcs of
+longitude would be required. The result for the spheroid may
+be expressed thus:&mdash;</p>
+
+<p class="center">
+a = 20926062 ft. = 6378206.4 metres.<br />
+b = 20855121 ft. = 6356583.8 metres.<br />
+       b : a = 293.98 : 294.98.</p>
+
+<p class="noind">As might be expected, the sum of the squares of the 40 latitude
+corrections, viz. 153.99, is greater in this figure than in that of
+three axes, where it amounts to 138.30. For this case, in the
+Indian arc the largest corrections are at Dodagunta, + 3.87&Prime;,
+and at Kalianpur, &minus; 3.68&Prime;. In the Russian arc the largest
+corrections are + 3.76&Prime;, at Torneå, and &minus; 3.31&Prime;, at Staro Nekrasovsk.
+Of the whole 40 corrections, 16 are under 1.0&Prime;, 10
+between 1.0&Prime; and 2.0&Prime;, 10 between 2.0&Prime; and 3.0&Prime;, and 4 over
+3.0&Prime;. The probable error of an observed latitude is ± 1.42&Prime;;
+for the spheroidal it would be very slightly larger. This quantity
+may be taken therefore as approximately the probable amount
+of local deflection.</p>
+
+<p>If &rho; be the radius of curvature of the meridian in latitude &phi;, &rho;&prime;
+that perpendicular to the meridian, D the length of a degree of
+the meridian, D&prime; the length of a degree of longitude, r the radius
+drawn from the centre of the earth, V the angle of the vertical
+with the radius-vector, then</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcc" colspan="2">Ft.</td> <td class="tcr">&nbsp;</td> <td class="tcr">&nbsp;</td> <td class="tcl">&nbsp;</td></tr>
+<tr><td class="tcr">&rho; =</td> <td class="tcl">20890606.6</td> <td class="tcr">&minus;</td> <td class="tcr">106411.5&nbsp; cos 2&phi;</td> <td class="tcl">+ 225.8 cos 4&phi;</td></tr>
+<tr><td class="tcr">&rho;&prime; =</td> <td class="tcl">20961607.3</td> <td class="tcr">&minus;</td> <td class="tcr">35590.9&nbsp;  cos 2&phi;</td> <td class="tcl">+ 45.2 cos 4&phi;</td></tr>
+<tr><td class="tcr">D =</td> <td class="tcl">&emsp;364609.87</td> <td class="tcr">&minus;</td> <td class="tcr">1857.14  cos 2&phi;</td> <td class="tcl">+ &nbsp;3.94 cos 4&phi;</td></tr>
+<tr><td class="tcr">D&prime; =</td> <td class="tcl">&emsp;365538.48 cos &phi;</td> <td class="tcr">&minus;</td> <td class="tcr">310.17   cos 3&phi;</td> <td class="tcl">+ &nbsp;0.39 cos 5&phi;</td></tr>
+<tr><td class="tcr">Log r/a =</td> <td class="tcl">9.9992645</td> <td class="tcr">+</td> <td class="tcr">.0007374 cos 2&phi;</td> <td class="tcl">&minus; .0000019 cos 4&phi;</td></tr>
+<tr><td class="tcr">V =</td> <td class="tcl" colspan="4">700.44&Prime; sin 2&phi; &minus; 1.19&Prime; sin 4&phi;.</td></tr>
+</table>
+
+<p>A.R. Clarke has recalculated the elements of the ellipsoid
+of the earth; his values, derived in 1880, in which he utilized
+the measurements of parallel arcs in India, are particularly in
+practice. These values are:&mdash;</p>
+
+<p class="center">
+a = 20926202 ft. = 6378249 metres,<br />
+b = 20854895 ft. = 6356515 metres,<br />
+      b : a = 292.465 : 293.465.</p>
+
+<div class="condensed">
+<p>The calculation of the elements of the ellipsoid of rotation from
+measurements of the curvature of arcs in any given azimuth by
+means of geographical longitudes, latitudes and azimuths is indicated
+in the article <span class="sc"><a href="#artlinks">Geodesy</a></span>; reference may be made to <i>Principal
+Triangulation</i>, Helmert&rsquo;s <i>Geodasie</i>, and the publications of the
+Kgl. Preuss. Geod. Inst.:&mdash;<i>Lotabweichungen</i> (1886), and <i>Die europ.
+Längengradmessung in 52° Br.</i> (1893). For the calculation of an
+ellipsoid with three unequal axes see <i>Comparison of Standards</i>,
+preface; and for non-elliptical meridians, <i>Principal Triangulation</i>,
+p. 733.</p>
+</div>
+
+<p class="pt2 center"><i>Gravitation-Measurements.</i></p>
+
+<p>According to Clairault&rsquo;s theorem (see above) the ellipticity e
+of the mathematical surface of the earth is equal to the difference
+<span class="spp">5</span>&frasl;<span class="suu">2</span>m &minus; &beta;, where m is the ratio of the centrifugal force at the
+equator to gravity at the equator, and &beta; is derived from the
+formula G = g(1 + &beta; sin²&phi;). Since the beginning of the 19th
+century many efforts have been made to determine the constants
+of this formula, and numerous expeditions undertaken to
+investigate the intensity of gravity in different latitudes. If m
+be known, it is only necessary to determine &beta; for the evaluation
+of e; consequently it is unnecessary to determine G absolutely,
+for the relative values of G at two known latitudes suffice.
+Such relative measurements are easier and more exact than
+absolute ones. In some cases the ordinary thread pendulum,
+<i>i.e.</i> a spherical bob suspended by a wire, has been employed;
+but more often a rigid metal rod, bearing a weight and a knife-edge
+on which it may oscillate, has been adopted. The main
+point is the constancy of the pendulum. From the formula for
+the time of oscillation of the mathematically ideal pendulum,
+t = 2&pi;&radic;<span class="ov">l/G</span>, l being the length, it follows that for two points
+G<span class="su">1</span> / G<span class="su">2</span> = t<span class="su">2</span>² / t<span class="su">1</span>².</p>
+
+<p>In 1808 J.B. Biot commenced his pendulum observations at
+several stations in western Europe; and in 1817-1825 Captain
+Louis de Freycinet and L.I. Duperrey prosecuted similar
+observations far into the southern hemisphere. Captain Henry
+Kater confined himself to British stations (1818-1819); Captain
+E. Sabine, from 1819 to 1829, observed similarly, with Kater&rsquo;s
+pendulum, at seventeen stations ranging from the West Indies
+<span class="pagenum"><a name="page809" id="page809"></a>809</span>
+to Greenland and Spitsbergen; and in 1824-1831, Captain
+Henry Foster (who met his death by drowning in Central
+America) experimented at sixteen stations; his observations
+were completed by Francis Baily in London. Of other workers
+in this field mention may be made of F.B. Lütke (1826-1829),
+a Russian rear-admiral, and Captains J.B. Basevi and W.T.
+Heaviside, who observed during 1865 to 1873 at Kew and at
+29 Indian stations, particularly at Moré in the Himalayas at a
+height of 4696 metres. Of the earlier absolute determinations we
+may mention those of Biot, Kater, and Bessel at Paris, London
+and Königsberg respectively. The measurements were particularly
+difficult by reason of the length of the pendulums
+employed, these generally being second-pendulums over 1
+metre long. In about 1880, Colonel Robert von Sterneck of
+Austria introduced the half-second pendulum, which permitted
+far quicker and more accurate work. The use of these pendulums
+spread in all countries, and the number of gravity stations
+consequently increased: in 1880 there were about 120, in 1900
+there were about 1600, of which the greater number were in
+Europe. Sir E. Sabine<a name="fa6c" id="fa6c" href="#ft6c"><span class="sp">6</span></a> calculated the ellipticity to be 1/288.5,
+a value shown to be too high by Helmert, who in 1884, with the
+aid of 120 stations, gave the value 1/299.26,<a name="fa7c" id="fa7c" href="#ft7c"><span class="sp">7</span></a> and in 1901, with
+about 1400 stations, derived the value 1/298.3.<a name="fa8c" id="fa8c" href="#ft8c"><span class="sp">8</span></a> The reason for
+the excessive estimate of Sabine is that he did not take into
+account the systematic difference between the values of G for
+continents and islands; it was found that in consequence of
+the constitution of the earth&rsquo;s crust (Pratt) G is greater on small
+islands of the ocean than on continents by an amount which may
+approach to 0.3 cm. Moreover, stations in the neighbourhood
+of coasts shelving to deep seas have a surplus, but a little smaller.
+Consequently, Helmert conducted his calculations of 1901 for
+continents and coasts separately, and obtained G for the coasts
+0.036 cm. greater than for the continents, while the value of &beta;
+remained the same. The mean value, reduced to continents, is</p>
+
+<p class="center">G = 978.03 (1 + 0.005302 sin²&phi; &minus; 0.000007 sin²2&phi;) cm/sec².</p>
+
+<p>The small term involving sin² 2&phi; could not be calculated with
+sufficient exactness from the observations, and is therefore taken
+from the theoretical views of Sir G.H. Darwin and E. Wiechert.
+For the constant g = 978.03 cm. another correction has been
+suggested (1906) by the absolute determinations made by F.
+Kühnen and Ph. Furtwängler at Potsdam.<a name="fa9c" id="fa9c" href="#ft9c"><span class="sp">9</span></a></p>
+
+<div class="condensed">
+<p>A report on the pendulum measurements of the 19th century
+has been given by Helmert in the <i>Comptes rendus des séances de
+la 13<span class="sp">e</span> conférence générale de l&rsquo;Association Géod. Internationale à
+Paris</i> (1900), ii. 139-385.</p>
+</div>
+
+<p>A difficulty presents itself in the case of the application of
+measurements of gravity to the determination of the figure of
+the earth by reason of the extrusion or standing out of the land-masses
+(continents, &amp;c.) above the sea-level. The potential
+of gravity has a different mathematical expression outside the
+masses than inside. The difficulty is removed by assuming
+(with Sir G.G. Stokes) the vertical condensation of the masses
+on the sea-level, without its form being considerably altered
+(scarcely 1 metre radially). Further, the value of gravity (g)
+measured at the height H is corrected to sea-level by + 2gH/R,
+where R is the radius of the earth. Another correction, due
+to P. Bouguer, is &minus; <span class="spp">3</span>&frasl;<span class="suu">2</span>g&delta;H/&rho;R, where &delta; is the density of the
+strata of height H, and &rho; the mean density of the earth.
+These two corrections are represented in &ldquo;Bouguer&rsquo;s Rule&rdquo;:
+g<span class="su">H</span> = g<span class="su">s</span> (1 &minus; 2H/R + 3&delta;H / 2&rho;R), where g<span class="su">H</span> is the gravity at height
+H, and g<span class="su">s</span> the value at sea-level. This is supposed to take
+into account the attraction of the elevated strata or plateau;
+but, from the analytical method, this is not correct; it is also
+disadvantageous since, in general, the land-masses are compensated
+subterraneously, by reason of the isostasis of the earth&rsquo;s
+crust.</p>
+
+<p>In 1849 Stokes showed that the normal elevations N of the
+geoid towards the ellipsoid are calculable from the deviations &Delta;g
+of the acceleration of gravity, <i>i.e.</i> the differences between the
+observed g and the value calculated from the normal G formula.
+The method assumes that gravity is measured on the earth&rsquo;s
+surface at a sufficient number of points, and that it is conformably
+reduced. In order to secure the convergence of the expansions
+in spherical harmonics, it is necessary to assume all masses
+outside a surface parallel to the surface of the sea at a depth of
+21 km. (= R × ellipticity) to be condensed on this surface (Helmert,
+<i>Geod.</i> ii. 172). In addition to the reduction with 2gH/R,
+there still result small reductions with mountain chains and
+coasts, and somewhat larger ones for islands. The sea-surface
+generally varies but very little by this condensation. The
+elevation (N) of the geoid is then equal to</p>
+
+<p class="center">N = R <span class="f150">&int;</span><span class="sp1">&pi;</span>
+  FG<span class="sp">&minus;1</span>&Delta;g<span class="su">&psi;</span>&psi;,</p>
+
+<p>where &psi; is the spherical distance from the point N, and &Delta;g<span class="su">&psi;</span>
+denotes the mean value of &Delta;g for all points in the same distance
+&psi; around; F is a function of &psi;, and has the following values:&mdash;</p>
+
+<table class="ws f90" summary="Contents">
+<tr><td class="tcc allb">&Psi; =</td> <td class="tcc allb">0°</td> <td class="tcc allb">10°</td> <td class="tcc allb">20°</td> <td class="tcc allb">30°</td> <td class="tcc allb">40°</td> <td class="tcc allb">50°</td> <td class="tcc allb">60°</td> <td class="tcc allb">70°</td> <td class="tcc allb">80°</td> <td class="tcc allb">90°</td> <td class="tcc allb">100°</td>
+  <td class="tcc allb">110°</td> <td class="tcc allb">120°</td> <td class="tcc allb">130°</td> <td class="tcc allb">140°</td> <td class="tcc allb">150°</td> <td class="tcc allb">160°</td> <td class="tcc allb">170°</td> <td class="tcc allb">180°</td></tr>
+<tr><td class="tcc allb">F = </td> <td class="tcc allb">1</td> <td class="tcc allb">1.22</td> <td class="tcc allb">0.94</td> <td class="tcc allb">0.47</td> <td class="tcc allb">&minus;0.06</td> <td class="tcc allb">&minus;0.54</td> <td class="tcc allb">&minus;0.90</td> <td class="tcc allb">&minus;1.08</td> <td class="tcc allb">&minus;1.08</td> <td class="tcc allb">&minus;0.91</td>
+  <td class="tcc allb">&minus;0.62</td> <td class="tcc allb">&minus;0.27</td> <td class="tcc allb">+0.08</td> <td class="tcc allb">0.36</td> <td class="tcc allb">0.53</td> <td class="tcc allb">0.56</td> <td class="tcc allb">0.46</td> <td class="tcc allb">0.26</td> <td class="tcc allb">0</td></tr>
+</table>
+
+<p class="noind">H. Poincaré (<i>Bull. Astr.</i>, 1901, p. 5) has exhibited N by means
+of Lamé&rsquo;s functions; in this case the condensation is effected
+on an ellipsoidal surface, which approximates to the geoid.
+This condensation is, in practice, the same as to the geoid
+itself.</p>
+
+<p>If we imagine the outer land-masses to be condensed on the
+sea-level, and the inner masses (which, together with the outer
+masses, causes the deviation of the geoid from the ellipsoid)
+to be compensated in the sea-level by a disturbing stratum
+(which, according to Gauss, is possible), and if these masses of
+both kinds correspond at the point N to a stratum of thickness
+D and density &delta;, then, according to Helmert (<i>Geod.</i> ii. 260) we
+have approximately</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">&Delta;g =</td> <td>3</td>
+<td rowspan="2">·</td> <td>g</td>
+<td rowspan="2"><span class="f150">(</span></td> <td>&delta;D</td>
+<td rowspan="2">&minus; N<span class="f150">)</span>.</td></tr>
+<tr><td class="denom">2</td> <td class="denom">R</td> <td class="denom">&rho;</td></tr></table>
+
+<p class="noind">Since N slowly varies empirically, it follows that in restricted
+regions (of a few 100 km. in diameter) &Delta;g is a measure of the
+variation of D. By applying the reduction of Bouguer to g, D is
+diminished by H and only gives the thickness of the ideal
+disturbing mass which corresponds to the perturbations due to
+subterranean masses. &Delta;g has positive values on coasts, small
+islands, and high and medium mountain chains, and occasionally
+in plains; while in valleys and at the foot of mountain ranges
+it is negative (up to 0.2 cm.). We conclude from this that the
+masses of smaller density existing under high mountain chains
+lie not only vertically underneath but also spread out sideways.</p>
+
+<p class="pt2 center"><i>The European Arc of Parallel in 52° Lat.</i></p>
+
+<p>Many measurements of degrees of longitudes along central
+parallels in Europe were projected and partly carried out as
+early as the first half of the 19th century; these, however,
+only became of importance after the introduction of the electric
+telegraph, through which calculations of astronomical longitudes
+obtained a much higher degree of accuracy. Of the greatest
+moment is the measurement near the parallel of 52° lat., which
+extended from Valentia in Ireland to Orsk in the southern Ural
+mountains over 69° long, (about 6750 km.). F.G.W. Struve,
+who is to be regarded as the father of the Russo-Scandinavian
+latitude-degree measurements, was the originator of this investigation.
+Having made the requisite arrangements with the
+<span class="pagenum"><a name="page810" id="page810"></a>810</span>
+governments in 1857, he transferred them to his son Otto, who, in
+1860, secured the co-operation of England. A new connexion
+of England with the continent, via the English Channel, was
+accomplished in the next two years; whereas the requisite
+triangulations in Prussia and Russia extended over several
+decennaries. The number of longitude stations originally
+arranged for was 15; and the determinations of the differences
+in longitude were uniformly commenced by the Russian observers
+E.I. von Forsch, J.I. Zylinski, B. Tiele and others; Feaghmain
+(Valentia) being reserved for English observers. With the
+concluding calculation of these operations, newer determinations
+of differences of longitudes were also applicable, by which the
+number of stations was brought up to 29. Since local deflections
+of the plumb-line were suspected at Feaghmain, the most
+westerly station, the longitude (with respect to Greenwich) of
+the trigonometrical station Killorglin at the head of Dingle Bay
+was shortly afterwards determined.</p>
+
+<div class="condensed">
+<p>The results (1891-1894) are given in volumes xlvii. and l. of the
+memoirs (Zapiski) of the military topographical division of the
+Russian general staff, volume li. contains a reconnexion of Orsk.
+The observations made west of Warsaw are detailed in the <i>Die
+europ. Längengradmessung in 52° Br.</i>, i. and ii., 1893, 1896, published
+by the Kgl. Preuss. Geod. Inst.</p>
+</div>
+
+<p>The following figures are quoted from Helmert&rsquo;s report
+&ldquo;Die Grösse der Erde&rdquo; (<i>Sitzb. d. Berl. Akad. d. Wiss.</i>, 1906,
+p. 535):&mdash;</p>
+
+<p class="pt1 center"><i>Easterly Deviation of the Astronomical Zenith</i>.</p>
+
+<table class="ws f90" summary="Contents">
+
+<tr><td class="tcc">Name.</td> <td class="tcc" colspan="3">Longitude.</td></tr>
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td></tr>
+<tr><td class="tcl">Feaghmain</td> <td class="tcr">&minus;10</td> <td class="tcr">21</td> <td class="tcr">&minus;3.3</td></tr>
+<tr><td class="tcl">Killorglin</td> <td class="tcr">&minus;9</td> <td class="tcr">47</td> <td class="tcr">+2.8</td></tr>
+<tr><td class="tcl">Haverfordwest</td> <td class="tcr">&minus;4</td> <td class="tcr">58</td> <td class="tcr">+1.6</td></tr>
+<tr><td class="tcl">Greenwich</td> <td class="tcr">0</td> <td class="tcr">0</td> <td class="tcr">+1.5</td></tr>
+<tr><td class="tcl">Rosendaël-Nieuport</td> <td class="tcr">+2</td> <td class="tcr">35</td> <td class="tcr">&minus;1.7</td></tr>
+<tr><td class="tcl">Bonn</td> <td class="tcr">+7</td> <td class="tcr">6</td> <td class="tcr">&minus;4.4</td></tr>
+<tr><td class="tcl">Göttingen</td> <td class="tcr">+9</td> <td class="tcr">57</td> <td class="tcr">&minus;2.4</td></tr>
+<tr><td class="tcl">Brocken</td> <td class="tcr">+10</td> <td class="tcr">37</td> <td class="tcr">+2.3</td></tr>
+<tr><td class="tcl">Leipzig</td> <td class="tcr">+12</td> <td class="tcr">23</td> <td class="tcr">+2.7</td></tr>
+<tr><td class="tcl">Rauenberg-Berlin</td> <td class="tcr">+13</td> <td class="tcr">23</td> <td class="tcr">+1.7</td></tr>
+<tr><td class="tcl">Grossenhain</td> <td class="tcr">+13</td> <td class="tcr">33</td> <td class="tcr">&minus;2.9</td></tr>
+<tr><td class="tcl">Schneekoppe</td> <td class="tcr">+15</td> <td class="tcr">45</td> <td class="tcr">+0.1</td></tr>
+<tr><td class="tcl">Springberg</td> <td class="tcr">+16</td> <td class="tcr">37</td> <td class="tcr">+0.8</td></tr>
+<tr><td class="tcl">Breslau-Rosenthal</td> <td class="tcr">+17</td> <td class="tcr">2</td> <td class="tcr">+3.5</td></tr>
+<tr><td class="tcl">Trockenberg</td> <td class="tcr">+18</td> <td class="tcr">53</td> <td class="tcr">&minus;0.5</td></tr>
+<tr><td class="tcl">Schönsee</td> <td class="tcr">+18</td> <td class="tcr">54</td> <td class="tcr">&minus;2.9</td></tr>
+<tr><td class="tcl">Mirov</td> <td class="tcr">+19</td> <td class="tcr">18</td> <td class="tcr">+2.2</td></tr>
+<tr><td class="tcl">Warsaw</td> <td class="tcr">+21</td> <td class="tcr">2</td> <td class="tcr">+1.9</td></tr>
+<tr><td class="tcl">Grodno</td> <td class="tcr">+23</td> <td class="tcr">50</td> <td class="tcr">&minus;2.8</td></tr>
+<tr><td class="tcl">Bobruisk</td> <td class="tcr">+29</td> <td class="tcr">14</td> <td class="tcr">+0.5</td></tr>
+<tr><td class="tcl">Orel</td> <td class="tcr">+36</td> <td class="tcr">4</td> <td class="tcr">+4.4</td></tr>
+<tr><td class="tcl">Lipetsk</td> <td class="tcr">+39</td> <td class="tcr">36</td> <td class="tcr">+0.2</td></tr>
+<tr><td class="tcl">Saratov</td> <td class="tcr">+46</td> <td class="tcr">3</td> <td class="tcr">+6.4</td></tr>
+<tr><td class="tcl">Samara</td> <td class="tcr">+50</td> <td class="tcr">5</td> <td class="tcr">&minus;2.6</td></tr>
+<tr><td class="tcl">Orenburg</td> <td class="tcr">+55</td> <td class="tcr">7</td> <td class="tcr">+1.7</td></tr>
+<tr><td class="tcl">Orsk</td> <td class="tcr">+58</td> <td class="tcr">34</td> <td class="tcr">&minus;8.0</td></tr>
+</table>
+
+<p>These deviations of the plumb-line correspond to an ellipsoid
+having an equatorial radius (<i>a</i>) of nearly 6,378,000 metres (prob.
+error ± 70 metres) and an ellipticity 1/299.15. The latter was
+taken for granted; it is nearly equal to the result from the
+gravity-measurements; the value for a then gives &Sigma;&eta;² a minimum
+(nearly). The astronomical values of the geographical
+longitudes (with regard to Greenwich) are assumed, according to
+the compensation of longitude differences carried out by van de
+Sande Bakhuyzen (<i>Comp. rend, des séances de la commission
+permanente de l&rsquo;Association Géod. Internationale à Genève, 1893,
+annexe A.I.</i>). Recent determinations (Albrecht, <i>Astr. Nach.</i>,
+3993/4) have introduced only small alterations in the deviations,
+a being slightly increased.</p>
+
+<p>Of considerable importance in the investigation of the great
+arc was the representation of the linear lengths found in different
+countries, in terms of the same unit. The necessity for this had
+previously occurred in the computation of the figure of the earth
+from latitude-degree-measurements. A.R. Clarke instituted
+an extensive series of comparisons at Southampton (see <i>Comparisons
+of Standards of Length of England, France, Belgium,
+Prussia, Russia, India and Australia, made at the Ordnance
+Survey Office, Southampton, 1866</i>, and a paper in the <i>Philosophical
+Transactions</i> for 1873, by Lieut.-Col. A.R. Clarke, C.B., R.E.,
+on the further comparisons of the standards of Austria, Spain,
+the United States, Cape of Good Hope and Russia) and found
+that 1 toise = 6.39453348 ft., 1 metre = 3.28086933 ft.</p>
+
+<p>In 1875 a number of European states concluded the metre
+convention, and in 1877 an international weights-and-measures
+bureau was established at Breteuil. Until this time the
+metre was determined by the end-surfaces of a platinum rod
+(<i>mètre des archives</i>); subsequently, rods of platinum-iridium,
+of cross-section <img style="width:18px; height:19px; vertical-align: middle;" src="images/img788i.jpg" alt="" />, were constructed, having engraved lines at
+both ends of the bridge, which determine the distance of a metre.
+There were thirty of the rods which gave as accurately as possible
+the length of the metre; and these were distributed among the
+different states (see <span class="sc"><a href="#artlinks">Weights and Measures</a></span>). Careful comparisons
+with several standard toises showed that the metre was
+not exactly equal to 443,296 lines of the toise, but, in round numbers,
+1/75000 of the length smaller. The metre according to the
+older relation is called the &ldquo;legal metre,&rdquo; according to the new
+relation the &ldquo;international metre.&rdquo; The values are (see <i>Europ.
+Längengradmessung</i>, i. p. 230):&mdash;</p>
+
+<p class="center">Legal metre = 3.28086933 ft., International metre = 3.2808257 ft.</p>
+
+<p>The values of a given above are in terms of the international
+metre; the earlier ones in legal metres, while the gravity
+formulae are in international metres.</p>
+
+<p class="pt2 center"><i>The International Geodetic Association</i> (<i>Internationale
+Erdmessung</i>).</p>
+
+<p>On the proposition of the Prussian lieutenant-general, Johann
+Jacob Baeyer, a conference of delegates of several European
+states met at Berlin in 1862 to discuss the question of a &ldquo;Central
+European degree-measurement.&rdquo; The first general conference
+took place at Berlin two years later; shortly afterwards other
+countries joined the movement, which was then named &ldquo;The
+European degree-measurement.&rdquo; From 1866 till 1886 Prussia
+had borne the expense incident to the central bureau at Berlin;
+but when in 1886 the operations received further extension and
+the title was altered to &ldquo;The International Earth-measurement&rdquo;
+or &ldquo;International Geodetic Association,&rdquo; the co-operating states
+made financial contributions to this purpose. The central bureau
+is affiliated with the Prussian Geodetic Institute, which, since
+1892, has been situated on the Telegraphenberg near Potsdam.
+After Baeyer&rsquo;s death Prof. Friedrich Robert Helmert was
+appointed director. The funds are devoted to the advancement
+of such scientific works as concern all countries and deal with
+geodetic problems of a general or universal nature. During the
+period 1897-1906 the following twenty-one countries belonged to
+the association:&mdash;Austria, Belgium, Denmark, England, France,
+Germany, Greece, Holland, Hungary, Italy, Japan, Mexico,
+Norway, Portugal, Rumania, Russia, Servia, Spain, Sweden,
+Switzerland and the United States of America. At the present
+time general conferences take place every three years.<a name="fa10c" id="fa10c" href="#ft10c"><span class="sp">10</span></a></p>
+
+<p>Baeyer projected the investigation of the curvature of the
+meridians and the parallels of the mathematical surface of the
+earth stretching from Christiania to Palermo for 12 degrees of
+longitude; he sought to co-ordinate and complete the network
+of triangles in the countries through which these meridians
+passed, and to represent his results by a common unit of length.
+This proposition has been carried out, and extended over the
+greater part of Europe; as a matter of fact, the network has,
+with trifling gaps, been carried over the whole of western and
+central Europe, and, by some chains of triangles, over European
+Russia. Through the co-operation of France, the network has
+been extended into north Africa as far as the geographical
+latitude of 32°; in Greece a network, united with those of Italy
+and Bosnia, has been carried out by the Austrian colonel, Heinrich
+Hartl; Servia has projected similar triangulations; Rumania
+has begun to make the triangle measurements, and three base
+<span class="pagenum"><a name="page811" id="page811"></a>811</span>
+lines have been measured by French officers with Brunner&rsquo;s
+apparatus. At present, in Rumania, there is being worked a
+connexion between the arc of parallel in lat. 47°/48° in Russia
+(stretching from Astrakan to Kishinev) with Austria-Hungary.
+In the latter country and in south Bavaria the connecting triangles
+for this parallel have been recently revised, as well as the French
+chain on the Paris parallel, which has been connected with the
+German net by the co-operation of German and French geodesists.
+This will give a long arc of parallel, really projected in the first
+half of the 19th century. The calculation of the Russian section
+gives, with an assumed ellipticity of 1/299.15, the value a =
+6377350 metres; this is rather uncertain, since the arc embraces
+only 19° in longitude.</p>
+
+<p>We may here recall that in France geodetic studies have
+recovered their former expansion under the vigorous impulse
+of Colonel (afterwards General) François Perrier. When occupied
+with the triangulation of Algeria, Colonel Perrier had conceived
+the possibility of the geodetic junction of Algeria to Spain, over
+the Mediterranean; therefore the French meridian line, which was
+already connected with England, and was thus produced to the
+60th parallel, could further be linked to the Spanish triangulation,
+cross thence into Algeria and extend to the Sahara, so as to form
+an arc of about 30° in length. But it then became urgent to
+proceed to a new measurement of the French arc, between
+Dunkirk and Perpignan. In 1869 Perrier was authorized to
+undertake that revision. He devoted himself to that work till
+the end of his career, closed by premature death in February
+1888, at the very moment when the <i>Dépôt de la guerre</i> had just
+been transformed into the Geographical Service of the Army,
+of which General F. Perrier was the first director. His work
+was continued by his assistant, Colonel (afterwards General)
+J.A.L. Bassot. The operations concerning the revision of the
+French arc were completed only in 1896. Meanwhile the French
+geodesists had accomplished the junction of Algeria to Spain,
+with the help of the geodesists of the Madrid Institute under
+General Carlos Ibañez (1879), and measured the meridian line
+between Algiers and El Aghuat (1881). They have since been
+busy in prolonging the meridians of El Aghuat and Biskra, so
+as to converge towards Wargla, through Ghardaïa and Tuggurt.
+The fundamental co-ordinates of the Panthéon have also been
+obtained anew, by connecting the Panthéon and the Paris
+Observatory with the five stations of Bry-sur-Marne, Morlu,
+Mont Valérien, Chatillon and Montsouris, where the observations
+of latitude and azimuth have been effected.<a name="fa11c" id="fa11c" href="#ft11c"><span class="sp">11</span></a></p>
+
+<p>According to the calculations made at the central bureau of
+the international association on the great meridian arc extending
+from the Shetland Islands, through Great Britain, France and
+Spain to El Aghuat in Algeria, a = 6377935 metres, the ellipticity
+being assumed as 1/299.15. The following table gives the difference:
+astronomical-geodetic latitude. The net does not follow
+the meridian exactly, but deviates both to the west and to the
+east; actually, the meridian of Greenwich is nearer the mean
+than that of Paris (Helmert, <i>Grösse d. Erde</i>).</p>
+
+<p class="pt1 center"><i>West Europe-Africa Meridian-arc.</i><a name="fa12c" id="fa12c" href="#ft12c"><span class="sp">12</span></a></p>
+
+<table class="ws f90" summary="Contents">
+<tr><td class="tcc">Name.</td> <td class="tcc" colspan="2">Latitude.</td> <td class="tcc">A.-G.</td></tr>
+<tr><td class="tcl">&nbsp;</td> <td class="tcc">°</td> <td class="tcc">&prime;</td> <td class="tcc">&Prime;</td></tr>
+<tr><td class="tcl">Saxavord</td> <td class="tcc">60</td> <td class="tcr">49.6</td> <td class="tcr">&minus;4.0</td></tr>
+<tr><td class="tcl">Balta</td> <td class="tcc">60</td> <td class="tcr">45.0</td> <td class="tcr">&minus;6.1</td></tr>
+<tr><td class="tcl">Ben Hutig</td> <td class="tcc">58</td> <td class="tcr">33.1</td> <td class="tcr">+0.3</td></tr>
+<tr><td class="tcl">Cowhythe</td> <td class="tcc">57</td> <td class="tcr">41.1</td> <td class="tcr">+7.3</td></tr>
+<tr><td class="tcl">Great Stirling</td> <td class="tcc">57</td> <td class="tcr">27.8</td> <td class="tcr">&minus;2.3</td></tr>
+<tr><td class="tcl">Kellie Law</td> <td class="tcc">56</td> <td class="tcr">14.9</td> <td class="tcr">&minus;3.7</td></tr>
+<tr><td class="tcl">Calton Hill</td> <td class="tcc">55</td> <td class="tcr">57.4</td> <td class="tcr">+3.5</td></tr>
+<tr><td class="tcl">Durham</td> <td class="tcc">54</td> <td class="tcr">46.1</td> <td class="tcr">&minus;0.9</td></tr>
+<tr><td class="tcl">Burleigh Moor</td> <td class="tcc">54</td> <td class="tcr">34.3</td> <td class="tcr">+2.1</td></tr>
+<tr><td class="tcl">Clifton Beacon</td> <td class="tcc">53</td> <td class="tcr">27.5</td> <td class="tcr">+1.3</td></tr>
+<tr><td class="tcl">Arbury Hill</td> <td class="tcc">52</td> <td class="tcr">13.4</td> <td class="tcr">&minus;3.0</td></tr>
+<tr><td class="tcl">Greenwich</td> <td class="tcc">51</td> <td class="tcr">28.6</td> <td class="tcr">&minus;2.5</td></tr>
+<tr><td class="tcl">Nieuport</td> <td class="tcc">51</td> <td class="tcr">7.8</td> <td class="tcr">&minus;0.4</td></tr>
+<tr><td class="tcl">Rosendaël</td> <td class="tcc">51</td> <td class="tcr">2.7</td> <td class="tcr">&minus;0.9</td></tr>
+<tr><td class="tcl">Lihons</td> <td class="tcc">49</td> <td class="tcr">49.9</td> <td class="tcr">+0.5</td></tr>
+<tr><td class="tcl">Panthéon</td> <td class="tcc">48</td> <td class="tcr">50.8</td> <td class="tcr">&minus;0.0</td></tr>
+<tr><td class="tcl">Chevry</td> <td class="tcc">48</td> <td class="tcr">0.5</td> <td class="tcr">+2.2</td></tr>
+<tr><td class="tcl">Saligny le Vif</td> <td class="tcc">47</td> <td class="tcr">2.7</td> <td class="tcr">+3.0</td></tr>
+<tr><td class="tcl">Arpheuille</td> <td class="tcc">46</td> <td class="tcr">13.7</td> <td class="tcr">+6.3</td></tr>
+<tr><td class="tcl">Puy de Dôme</td> <td class="tcc">45</td> <td class="tcr">46.5</td> <td class="tcr">+7.0</td></tr>
+<tr><td class="tcl">Rodez</td> <td class="tcc">44</td> <td class="tcr">21.4</td> <td class="tcr">+1.7</td></tr>
+<tr><td class="tcl">Carcassonne</td> <td class="tcc">43</td> <td class="tcr">13.3</td> <td class="tcr">+0.7</td></tr>
+<tr><td class="tcl">Rivesaltes</td> <td class="tcc">42</td> <td class="tcr">45.2</td> <td class="tcr">&minus;0.7</td></tr>
+<tr><td class="tcl">Montolar</td> <td class="tcc">41</td> <td class="tcr">38.5</td> <td class="tcr">+3.6</td></tr>
+<tr><td class="tcl">Lérida</td> <td class="tcc">41</td> <td class="tcr">37.0</td> <td class="tcr">&minus;0.2</td></tr>
+<tr><td class="tcl">Javalon</td> <td class="tcc">40</td> <td class="tcr">13.8</td> <td class="tcr">&minus;0.2</td></tr>
+<tr><td class="tcl">Desierto</td> <td class="tcc">40</td> <td class="tcr">5.0</td> <td class="tcr">&minus;4.5</td></tr>
+<tr><td class="tcl">Chinchilla</td> <td class="tcc">38</td> <td class="tcr">55.2</td> <td class="tcr">+2.2</td></tr>
+<tr><td class="tcl">Mola de Formentera</td> <td class="tcc">38</td> <td class="tcr">39.9</td> <td class="tcr">&minus;1.2</td></tr>
+<tr><td class="tcl">Tetíca</td> <td class="tcc">37</td> <td class="tcr">15.2</td> <td class="tcr">+3.5</td></tr>
+<tr><td class="tcl">Roldan</td> <td class="tcc">36</td> <td class="tcr">56.6</td> <td class="tcr">&minus;6.0</td></tr>
+<tr><td class="tcl">Conjuros</td> <td class="tcc">36</td> <td class="tcr">44.4</td> <td class="tcr">&minus;12.6</td></tr>
+<tr><td class="tcl">Mt. Sabiha</td> <td class="tcc">35</td> <td class="tcr">39.6</td> <td class="tcr">+6.5</td></tr>
+<tr><td class="tcl">Nemours</td> <td class="tcc">35</td> <td class="tcr">5.8</td> <td class="tcr">+7.4</td></tr>
+<tr><td class="tcl">Bouzaréah</td> <td class="tcc">36</td> <td class="tcr">48.0</td> <td class="tcr">+2.9</td></tr>
+<tr><td class="tcl">Algiers (Voirol)</td> <td class="tcc">36</td> <td class="tcr">45.1</td> <td class="tcr">&minus;9.1</td></tr>
+<tr><td class="tcl">Guelt ès Stel</td> <td class="tcc">35</td> <td class="tcr">7.8</td> <td class="tcr">&minus;1.0</td></tr>
+<tr><td class="tcl">El Aghuat</td> <td class="tcc">33</td> <td class="tcr">48.0</td> <td class="tcr">&minus;2.8</td></tr>
+</table>
+
+<table class="nobctr" style="clear: both;" summary="Illustration">
+<tr><td class="figcenter"><img style="width:525px; height:907px" src="images/img811.jpg" alt="" /></td></tr></table>
+
+<p><span class="pagenum"><a name="page812" id="page812"></a>812</span></p>
+
+<p>While the radius of curvature of this arc is obviously not uniform
+(being, in the mean, about 600 metres greater in the northern
+than in the southern part), the Russo-Scandinavian meridian arc
+(from 45° to 70°), on the other hand, is very uniformly curved,
+and gives, with an ellipticity of 1/299.15, a = 6378455 metres;
+this arc gives the plausible value 1/298.6 for the ellipticity. But
+in the case of this arc the orographical circumstances are more
+favourable.</p>
+
+<p>The west-European and the Russo-Scandinavian meridians
+indicate another anomaly of the geoid. They were connected
+at the Central Bureau by means of east-to-west triangle chains
+(principally by the arc of parallel measurements in lat. 52°);
+it was shown that, if one proceeds from the west-European
+meridian arcs, the differences between the astronomical and
+geodetic latitudes of the Russo-Scandinavian arc become some
+4&Prime; greater.<a name="fa13c" id="fa13c" href="#ft13c"><span class="sp">13</span></a></p>
+
+<p>The central European meridian, which passes through Germany
+and the countries adjacent on the north and south, is under
+review at Potsdam (see the publications of the Kgl. Preuss. Geod.
+Inst., <i>Lotabweichungen</i>, Nos. 1-3). Particular notice must be
+made of the Vienna meridian, now carried southwards to Malta.
+The Italian triangulation is now complete, and has been joined
+with the neighbouring countries on the north, and with Tunis
+on the south.</p>
+
+<p>The United States Coast and Geodetic Survey has published
+an account of the transcontinental triangulation and measurement
+of an arc of the parallel of 39°, which extends from Cape May
+(New Jersey), on the Atlantic coast, to Point Arena (California),
+on the Pacific coast, and embraces 48° 46&prime; of longitude, with
+a linear development of about 4225 km. (2625 miles). The
+triangulation depends upon ten base-lines, with an aggregate
+length of 86 km. the longest exceeding 17 km. in length, which
+have been measured with the utmost care. In crossing the
+Rocky Mountains, many of its sides exceed 100 miles in length,
+and there is one side reaching to a length of 294 km., or 183
+miles; the altitude of many of the stations is also considerable,
+reaching to 4300 metres, or 14,108 ft., in the case of Pike&rsquo;s Peak,
+and to 14,421 ft. at Elbert Peak, Colo. All geometrical conditions
+subsisting in the triangulation are satisfied by adjustment,
+inclusive of the required accord of the base-lines, so that the
+same length for any given line is found, no matter from what
+line one may start.<a name="fa14c" id="fa14c" href="#ft14c"><span class="sp">14</span></a></p>
+
+<p>Over or near the arc were distributed 109 latitude stations,
+occupied with zenith telescopes; 73 azimuth stations; and
+29 telegraphically determined longitudes. It has thus been
+possible to study in a very complete manner the deviations
+of the vertical, which in the mountainous regions sometimes
+amount to 25 seconds, and even to 29 seconds.</p>
+
+<p>With the ellipticity 1/299.15, a = 6377897 ± 65 metres (prob.
+error); in this calculation, however, some exceedingly perturbed
+stations are excluded; for the employed stations the mean
+perturbation in longitude is ± 4.9&Prime; (zenith-deflection east-to-west
+± 3.8&Prime;).</p>
+
+<p>The computations relative to another arc, the &ldquo;eastern
+oblique arc of the United States,&rdquo; are also finished.<a name="fa15c" id="fa15c" href="#ft15c"><span class="sp">15</span></a> It extends
+from Calais (Maine) in the north-east, to the Gulf of Mexico,
+and terminates at New Orleans (Louisiana), in the south. Its
+length is 2612 km. (1623 miles), the difference of latitude 15° 1&prime;,
+and of longitude 22° 47&prime;. In the main, the triangulation follows
+the Appalachian chain of mountains, bifurcating once, so as
+to leave an oval space between the two branches. It includes
+among its stations Mount Washington (1920 metres) and Mount
+Mitchell (2038 metres). It depends upon six base-lines, and the
+adjustment is effected in the same manner as for the arc of the
+parallel. The astronomical data have been afforded by 71
+latitude stations, 17 longitude stations, and 56 azimuth stations,
+distributed over the whole extent of the arc. The resulting
+dimensions of an osculating spheroid were found to be</p>
+
+<p class="center">a = 6378157 metres ± 90 (prob. error),<br />
+e (ellipticity) = 1/304.5 ± 1.9 (prob. error).</p>
+
+<p>With the ellipticity 1/399.15, a = 6378041 metres ± 80 (prob. er.).</p>
+
+<p>During the years 1903-1906 the United States Coast and
+Geodetic Survey, under the direction of O.H. Tittmann and the
+special management of John F. Hayford, executed a calculation
+of the best ellipsoid of rotation for the United States. There were
+507 astronomical determinations employed, all the stations being
+connected through the net-work of triangles. The observed
+latitudes, longitude and azimuths were improved by the attractions
+of the earth&rsquo;s crust on the hypothesis of isostasis for three
+depths of the surface of 114, 121 and 162 km., where the isostasis
+is complete. The land-masses, within the distance of 4126 km.,
+were taken into consideration. In the derivation of an ellipsoid
+of rotation, the first case proved itself the most favourable,
+and there resulted:&mdash;</p>
+
+<p class="center">a = 6378283 metres ± 74 (prob. er.), ellipticity = 1/297.8 ± 0.9 (prob. er.).</p>
+
+<p class="noind">The most favourable value for the depth of the isostatic surface
+is approximately 114 km.</p>
+
+<p>The measurement of a great meridian arc, in long. 98° W.,
+has been commenced; it has a range of latitude of 23°, and will
+extend over 50° when produced southwards and northwards by
+Mexico and Canada. It may afterwards be connected with the
+arc of Quito. A new measurement of the meridian arc of Quito
+was executed in the years 1901-1906 by the <i>Service géographique</i>
+of France under the direction of the Académie des Sciences,
+the ground having been previously reconnoitred in 1899. The
+new arc has an amplitude in latitude of 5° 53&prime; 33&Prime;, and stretches
+from Tulcan (lat. 0° 48&prime; 25&Prime;) on the borders of Columbia and
+Ecuador, through Columbia to Payta (lat. &minus; 5° 5&prime; 8&Prime;) in Peru.
+The end-points, at which the chain of triangles has a slight
+north-easterly trend, show a longitude difference of 3°. Of the
+74 triangle points, 64 were latitude stations; 6 azimuths and
+8 longitude-differences were measured, three base-lines were
+laid down, and gravity was determined from six points, in order
+to maintain indications over the general deformation of the
+geoid in that region. Computations of the attraction of the
+mountains on the plumb-line are also being considered. The
+work has been much delayed by the hardships and difficulties
+encountered. It was conducted by Lieut.-Colonel Robert
+Bourgeois, assisted by eleven officers and twenty-four soldiers
+of the geodetic branch of the <i>Service géographique</i>. Of these
+officers mention may be made of Commandant E. Maurain,
+who retired in 1904 after suffering great hardships; Commandant
+L. Massenet, who died in 1905; and Captains I. Lacombe,
+A. Lallemand, and Lieut. Georges Perrier (son of General
+Perrier). It is conceivable that the chain of triangles in longitude
+98° in North America may be united with that of Ecuador and
+Peru: a continuous chain over the whole of America is certainly
+but a question of time. During the years 1899-1902 the
+measurement of an arc of meridian was made in the extreme
+north, in Spitzbergen, between the latitudes 76° 38&prime; and 80° 50&prime;,
+according to the project of P.G. Rosén. The southern part
+was determined by the Russians&mdash;O. Bäcklund, Captain D.D.
+Sergieffsky, F.N. Tschernychev, A. Hansky and others&mdash;during
+1899-1901, with the aid of 1 base-line, 15 trigonometrical, 11
+latitude and 5 gravity stations. The northern part, which
+has one side in common with the southern part, has been
+determined by Swedes (Professors Rosén, father and son, E.
+Jäderin, T. Rubin and others), who utilized 1 base-line, 9 azimuth
+measurements, 18 trigonometrical, 17 latitude and 5 gravity
+stations. The party worked under excessive difficulties, which
+were accentuated by the arctic climate. Consequently, in the
+first year, little headway was made.<a name="fa16c" id="fa16c" href="#ft16c"><span class="sp">16</span></a></p>
+
+<p><span class="pagenum"><a name="page813" id="page813"></a>813</span></p>
+
+<p>Sir David Gill, when director of the Royal Observatory, Cape
+Town, instituted the magnificent project of working a latitude-degree
+measurement along the meridian of 30° long. This
+meridian passes through Natal, the Transvaal, by Lake Tanganyika,
+and from thence to Cairo; connexion with the Russo-Scandinavian
+meridian arc of the same longitude should be
+made through Asia Minor, Turkey, Bulgaria and Rumania.
+With the completion of this project a continuous arc of 105°
+in latitude will have been measured.<a name="fa17c" id="fa17c" href="#ft17c"><span class="sp">17</span></a></p>
+
+<p>Extensive triangle chains, suitable for latitude-degree measurements,
+have also been effected in Japan and Australia.</p>
+
+<p>Besides, the systematization of gravity measurements is of
+importance, and for this purpose the association has instituted
+many reforms. It has ensured that the relative measurements
+made at the stations in different countries should be reduced
+conformably with the absolute determinations made at Potsdam;
+the result was that, in 1906, the intensities of gravitation at
+some 2000 stations had been co-ordinated. The intensity of
+gravity on the sea has been determined by the comparison of
+barometric and hypsometric observations (Mohn&rsquo;s method).
+The association, at the proposal of Helmert, provided the
+necessary funds for two expeditions:&mdash;English Channel&mdash;Rio
+de Janeiro, and the Red Sea&mdash;Australia&mdash;San Francisco&mdash;Japan.
+Dr O. Hecker of the central bureau was in charge; he successfully
+overcame the difficulties of the work, and established the tenability
+of the isostatic hypothesis, which necessitates that the
+intensity of gravity on the deep seas has, in general, the same
+value as on the continents (without regard to the proximity of
+coasts).<a name="fa18c" id="fa18c" href="#ft18c"><span class="sp">18</span></a></p>
+
+<p>As the result of the more recent determinations, the ellipticity,
+compression or flattening of the ellipsoid of the earth may
+be assumed to be very nearly 1/298.3; a value determined in
+1901 by Helmert from the measurements of gravity. The semi-major
+axis, a, of the meridian ellipse may exceed 6,378,000 inter.
+metres by about 200 metres. The central bureau have adopted,
+for practical reasons, the value 1/299.15, after Bessel, for which
+tables exist; and also the value a = 6377397.155 (1 + 0.0001).</p>
+
+<p>The methods of theoretical astronomy also permit the evaluation
+of these constants. The semi-axis a is calculable from the
+parallax of the moon and the acceleration of gravity on the
+earth; but the results are somewhat uncertain: the ellipticity
+deduced from lunar perturbations is 1/297.8 ± 2 (Helmert,
+<i>Geodäsie</i>, ii. pp. 460-473); William Harkness (<i>The Solar
+Parallax and its related Constants</i>, 1891) from all possible data
+derived the values: ellipticity = 1/300.2 ± 3, a = 6377972 ± 125
+metres. Harkness also considered in this investigation the relation
+of the ellipticity to precession and nutation; newer investigations
+of the latter lead to the limiting values 1/296, 1/298
+(Wiechert). It was clearly noticed in this method of determination
+that the influence of the assumption as to the density of the
+strata in the interior of the earth was but very slight (Radau,
+<i>Bull. astr.</i> ii. (1885) 157). The deviations of the geoid from the
+flattened ellipsoid of rotation with regard to the heights (the
+directions of normals being nearly the same) will scarcely
+exceed ± 100 metres (Helmert).<a name="fa19c" id="fa19c" href="#ft19c"><span class="sp">19</span></a></p>
+
+<p>The basis of the degree- and gravity-measurements is actually
+formed by a stationary sea-surface, which is assumed to be level.
+However, by the influence of winds and ocean currents the mean
+surface of the sea near the coasts (which one assumes as the
+fundamental sea-surface) can deviate somewhat from a level
+surface. According to the more recent levelling it varies at the
+most by only some decimeters.<a name="fa20c" id="fa20c" href="#ft20c"><span class="sp">20</span></a></p>
+
+<p>It is well known that the masses of the earth are continually
+undergoing small changes; the earth&rsquo;s crust and sea-surface
+reciprocally oscillate, and the axis of rotation vibrates relatively
+to the body of the earth. The investigation of these problems
+falls in the programme of the Association. By continued observations
+of the water-level on sea-coasts, results have already been
+obtained as to the relative motions of the land and sea (cf.
+<span class="sc"><a href="#artlinks">Geology</a></span>); more exact levelling will, in the course of time,
+provide observations on countries remote from the sea-coast.
+Since 1900 an international service has been organized between
+some astronomical stations distributed over the north parallel
+of 39° 8&prime;, at which geographical latitudes are observed whenever
+possible. The association contributes to all these stations,
+supporting four entirely: two in America, one in Italy, and one
+in Japan; the others partially (Tschardjui in Russia, and
+Cincinnati observatory). Some observatories, especially Pulkowa,
+Leiden and Tokyo, take part voluntarily. Since 1906 another
+station for South America and one for Australia in latitude
+&minus; 31° 55&prime; have been added. According to the existing data,
+geographical latitudes exhibit variations amounting to ± 0.25&Prime;,
+which, for the greater part, proceed from a twelve- and a fourteen-month
+period.<a name="fa21c" id="fa21c" href="#ft21c"><span class="sp">21</span></a></p>
+<div class="author">(A. R. C; F. R. H.)</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1c" id="ft1c" href="#fa1c"><span class="fn">1</span></a> <i>Eratosthenes Batavus, seu de terrae ambitus vera quantitate
+suscitatus, a Willebrordo Snellio, Lugduni-Batavorum</i> (1617).</p>
+
+<p><a name="ft2c" id="ft2c" href="#fa2c"><span class="fn">2</span></a> O. <span class="correction" title="amended from Callendreau">Callandreau</span>, &ldquo;Mémoire sur la théorie de la figure des
+planètes,&rdquo; <i>Ann. obs. de Paris</i> (1889); G.H. Darwin, &ldquo;The Theory
+of the Figure of the Earth carried to the Second Order of Small
+Quantities,&rdquo; <i>Mon. Not. R.A.S.</i>, 1899; E. Wiechert, &ldquo;Über die
+Massenverteilung im Innern der Erde,&rdquo; <i>Nach. d. kön. G. d. W. zu
+Gött.</i>, 1897.</p>
+
+<p><a name="ft3c" id="ft3c" href="#fa3c"><span class="fn">3</span></a> See I. Todhunter, <i>Proc. Roy. Soc.</i>, 1870.</p>
+
+<p><a name="ft4c" id="ft4c" href="#fa4c"><span class="fn">4</span></a> J.H. Jeans, &ldquo;On the Vibrations and Stability of a Gravitating
+Planet,&rdquo; <i>Proc. Roy. Soc.</i> vol. 71; G.H. Darwin, &ldquo;On the Figure
+and Stability of a liquid Satellite,&rdquo; <i>Phil. Trans.</i> 206, p. 161; A.E.H.
+Love, &ldquo;The Gravitational Stability of the Earth,&rdquo; <i>Phil. Trans.</i> 207,
+p. 237; <i>Proc. Roy. Soc.</i> vol. 80.</p>
+
+<p><a name="ft5c" id="ft5c" href="#fa5c"><span class="fn">5</span></a> <i>Survey of India</i>, &ldquo;The Attraction of the Himalaya Mountains
+upon the Plumb Line in India&rdquo; (1901), p. 98.</p>
+
+<p><a name="ft6c" id="ft6c" href="#fa6c"><span class="fn">6</span></a> <i>Account of Experiments to Determine the Figure of the Earth by
+means of a Pendulum vibrating Seconds in Different Latitudes</i> (1825).</p>
+
+<p><a name="ft7c" id="ft7c" href="#fa7c"><span class="fn">7</span></a> Helmert, <i>Theorien d. höheren Geod.</i> ii., Leipzig, 1884.</p>
+
+<p><a name="ft8c" id="ft8c" href="#fa8c"><span class="fn">8</span></a> Helmert, <i>Sitzber. d. kgl. preuss. Ak. d. Wiss. zu Berlin</i> (1901),
+p. 336.</p>
+
+<p><a name="ft9c" id="ft9c" href="#fa9c"><span class="fn">9</span></a> &ldquo;Bestimmung der absoluten Grösse der Schwerkraft zu Potsdam
+mit Reversionspendeln&rdquo; (<i>Veröffentlichung des kgl. preuss. Geod. Inst.</i>,
+N.F., No. 27).</p>
+
+<p><a name="ft10c" id="ft10c" href="#fa10c"><span class="fn">10</span></a> <i>Die Königl. Observatorien für Astrophysik, Meteorologie und
+Geodäsie bei Potsdam</i> (Berlin, 1890); <i>Verhandlungen der I. Allgemeinen
+Conferenz der Bevollmächtigten zur mitteleurop. Gradmessung</i>,
+October, 1864, in Berlin (Berlin, 1865); A. Hirsch, <i>Verhandlungen
+der VIII. Allg. Conf. der Internationalen Erdmessung</i>, October, 1886,
+in Berlin (Berlin, 1887); and <i>Verhandlungen der XI. Allg. Conf.
+d. I. E.</i>, October, 1895, in Berlin (1896).</p>
+
+<p><a name="ft11c" id="ft11c" href="#fa11c"><span class="fn">11</span></a> Ibañez and Perrier, <i>Jonction géod. et astr. de l&rsquo;Algérie avec
+l&rsquo;Espagne</i> (Paris, 1886); <i>Mémorial du dépôt général de la guerre</i>,
+t. xii.: <i>Nouvelle méridienne de France</i> (Paris, 1885, 1902, 1904);
+<i>Comptes rendus des séances de la 12<span class="sp">e</span>-19<span class="sp">e</span> conférence générale de l&rsquo;Assoc.
+Géod. Internat.</i>, 1898 at Stuttgart, 1900 at Paris, 1903 at Copenhagen,
+1906 at Budapest (Berlin, 1899, 1901, 1904, 1908); A. Ferrero,
+<i>Rapport sur les triangulations, prés. à la 12<span class="sp">e</span> conf. gén. 1898</i>.</p>
+
+<p><a name="ft12c" id="ft12c" href="#fa12c"><span class="fn">12</span></a> R. Schumann, <i>C. r. de Budapest</i>, p. 244.</p>
+
+<p><a name="ft13c" id="ft13c" href="#fa13c"><span class="fn">13</span></a> O. and A. Börsch, &ldquo;Verbindung d. russ.-skandinav. mit der
+franz.-engl. Breitengradmessung&rdquo; (<i>Verhandlungen der 9. Allgem.
+Conf. d. I. E. in Paris, 1889</i>, Ann. xi.).</p>
+
+<p><a name="ft14c" id="ft14c" href="#fa14c"><span class="fn">14</span></a> U.S. Coast and Geodetic Survey; H.S. Pritchett, superintendent.
+<i>The Transcontinental Triangulation and the American Arc
+of the Parallel</i>, by C.A. Schott (Washington, 1900).</p>
+
+<p><a name="ft15c" id="ft15c" href="#fa15c"><span class="fn">15</span></a> U.S. Coast and Geodetic Survey; O.H. Tittmann, superintendent.
+<i>The Eastern Oblique Arc of the United States</i>, by C.A.
+Schott (1902).</p>
+
+<p><a name="ft16c" id="ft16c" href="#fa16c"><span class="fn">16</span></a> <i>Missions scientifiques pour la mesure d&rsquo;un arc de méridien au
+Spitzberg entreprises en 1899-1902 sous les auspices des gouvernements
+russe et suédois.</i> <i>Mission russe</i> (St Pétersbourg, 1904); <i>Mission
+suédoise</i> (Stockholm, 1904).</p>
+
+<p><a name="ft17c" id="ft17c" href="#fa17c"><span class="fn">17</span></a> Sir David Gill, <i>Report on the Geodetic Survey of South Africa,
+1833-1892</i> (Cape Town, 1896), vol. ii. 1901, vol. iii. 1905.</p>
+
+<p><a name="ft18c" id="ft18c" href="#fa18c"><span class="fn">18</span></a> O. Hecker, <i>Bestimmung der Schwerkraft a. d. Atlantischen
+Ozean</i> (Veröffentl. d. Kgl. Preuss. Geod. Inst. No. 11), Berlin,
+1903.</p>
+
+<p><a name="ft19c" id="ft19c" href="#fa19c"><span class="fn">19</span></a> F.R. Helmert. &ldquo;Neuere Fortschritte in der Erkenntnis der
+math. Erdgestalt&rdquo; (<i>Verhandl. des VII. Internationalen Geographen-Kongresses,
+Berlin, 1899</i>), London, 1901.</p>
+
+<p><a name="ft20c" id="ft20c" href="#fa20c"><span class="fn">20</span></a> C. Lallemand, &ldquo;Rapport sur les travaux du service du nivellement
+général de la France, de 1900 à 1906&Prime; (<i>Comp. rend. de la 14<span class="sp">e</span>
+conf. gén. de l&rsquo;Assoc. Géod-Intern., 1903</i>, p. 178).</p>
+
+<p><a name="ft21c" id="ft21c" href="#fa21c"><span class="fn">21</span></a> T. Albrecht, <i>Resultate des internat. Breitendienstes</i>, i. and ii.
+(Berlin, 1903 and 1906); F. Klein and A. Sommerfeld, <i>Über die
+Theorie des Kreisels</i>, iii. p. 672; R. Spitaler, &ldquo;Die periodischen Luftmassenverschiebungen
+und ihr Einfluss auf die Lagenänderung der
+Erdaxe&rdquo; (<i>Petermanns Mitteilungen, Ergänzungsheft</i>, 137); S. Newcomb,
+&ldquo;Statement of the Theoretical Laws of the Polar Motion&rdquo;
+(<i>Astronomical Journal</i>, 1898, xix. 158); F.R. Helmert, &ldquo;Zur
+Erklärung der beobachteten Breitenänderungen&rdquo; (<i>Astr. Nachr.</i> No.
+3014); J. Weeder, &ldquo;The 14-monthly period of the motion of the
+Pole from determinations of the azimuth of the meridian marks of
+the Leiden observatory&rdquo; (<i>Kon. Ak. van Wetenschappen to Amsterdam</i>,
+1900); A. Sokolof, &ldquo;Détermination du mouvement du pôle terr.
+au moyen des mires méridiennes de Poulkovo&rdquo; (<i>Mél. math. et astr.</i>
+vii., 1894); J. Bonsdorff, &ldquo;Beobachtungen von &delta; Cassiopejae mit
+dem grossen Zenitteleskop&rdquo; (<i>Mitteilungen der Nikolai-Hauptsternwarte
+zu Pulkowo</i>, 1907); J. Larmor and E.H. Hills, &ldquo;The irregular
+movement of the Earth&rsquo;s axis of rotation: a contribution towards
+the analysis of its causes&rdquo; (<i>Monthly Notices R.A.S.</i>, 1906, lxvii. 22);
+A.S. Cristie, &ldquo;The latitude variation Tide&rdquo; (<i>Phil. Soc. of Wash.</i>,
+1895, <i>Bull.</i> xiii. 103); H.G. van de Sande Bakhuysen, &ldquo;Über die
+Änderung der Polhöhe&rdquo; (<i>Astr. Nachr.</i> No. 3261); A.V. Bäcklund,
+&ldquo;Zur Frage nach der Bewegung des Erdpoles&rdquo; (<i>Astr. Nachr.</i>
+No. 3787); R. Schumann, &ldquo;Über die Polhöhenschwankung&rdquo;
+(<i>Astr. Nachr.</i> No. 3873); &ldquo;Numerische Untersuchung&rdquo; (<i>Ergänzungshefte
+zu den Astr. Nachr.</i> No. 11); <i>Weitere Untersuchungen</i>
+(No. 4142); <i>Bull. astr.</i>, 1900, June, report of different theoretical
+memoirs.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARTH CURRENTS.<a name="ar42" id="ar42"></a></span> After the invention of telegraphy it
+was soon found that telegraph lines in which the circuit is completed
+by the earth are traversed by natural electric currents
+which occasionally interfere seriously with their use, and which
+are known as &ldquo;earth currents.&rdquo;</p>
+
+<p>1. Amongst the pioneers in investigating the subject were
+several English telegraphists, <i>e.g.</i> W.H. Barlow (<b>1</b>) and C.V.
+Walker (<b>2</b>), who were in charge respectively of the Midland and
+South-Eastern telegraph systems. Barlow noticed the existence
+of a more or less regular diurnal variation, and the result&mdash;confirmed
+by all subsequent investigators&mdash;that earth currents
+proper occur in a line only when both ends are earthed. Walker,
+as the result of general instructions issued to telegraph clerks,
+collected numerous statistics as to the phenomena during times
+of large earth currents. His results and those given by Barlow
+both indicate that the lines to suffer most from earth currents
+in England have the general direction N.E. to S.W. As Walker
+points out, it is the direction of the terminal plates relative to
+one another that is the essential thing. At the same time he
+noticed that whilst at any given instant the currents in parallel
+lines have with rare exceptions the same direction, some lines
+show normally stronger currents than others, and he suggested
+that differences in the geological structure of the intervening
+ground might be of importance. This is a point which seems
+still somewhat obscure.</p>
+
+<p>Our present knowledge of the subject owes much to practical
+men, but even in the early days of telegraphy the fact that
+telegraph systems are commercial undertakings, and cannot allow
+<span class="pagenum"><a name="page814" id="page814"></a>814</span>
+the public to wait the convenience of science, was a serious
+obstacle to their employment for research. Thus Walker
+feelingly says, when regretting his paucity of data during a
+notable earth current disturbance: &ldquo;Our clerks were at their
+wits&rsquo; end to clear off the telegrams.... At a time when observations
+would have been very highly acceptable they were too much
+occupied with their ordinary duties.&rdquo; Some valuable observations
+have, however, been made on long telegraph lines where
+special facilities have been given.</p>
+
+<p>Amongst these may be mentioned the observations on French
+lines in 1883 described by E.E. Blavier (<b>3</b>), and those on two
+German lines Berlin-Thorn and Berlin-Dresden during 1884 to
+1888 discussed by B. Weinstein (<b>4</b>).</p>
+
+<p>2. Of the experimental lines specially constructed perhaps
+the best known are the Greenwich lines instituted by Sir G.B.
+Airy (<b>5</b>), the lines at Pawlowsk due to H. Wild (<b>6</b>), and those at
+Parc Saint Maur, near Paris (<b>7</b>).</p>
+
+<p><i>Experimental Lines.</i>&mdash;At Greenwich observations were commenced
+in 1865, but there have been serious disturbances due
+to artificial currents from electric railways for many years.
+There are two lines, one to Dartford distant about 10 m., in a
+direction somewhat south of east, the other to Croydon distant
+about 8 m., in a direction west of south.</p>
+
+<p>Information from a single line is incomplete, and unless this
+is clearly understood erroneous ideas may be derived. The times
+at which the current is largest and least, or when it vanishes, in
+an east-west line, tell nothing directly as to the amplitude at the
+time of the resultant current. The lines laid down at Pawlowsk
+in 1883 lay nearly in and perpendicular to the geographical
+meridian, a distinct desideratum, but were only about 1 km.
+long. The installation at Parc Saint Maur, discussed by T.
+Moureaux, calls for fuller description. There are three lines,
+one having terminal earth plates 14.8 km. apart in the geographical
+meridian, a second having its earth plates due east and
+west of one another, also 14.8 km. apart, and the third forming
+a closed circuit wholly insulated from the ground. In each of
+the three lines is a Deprez d&rsquo;Arsonval galvanometer. Light
+reflected from the galvanometer mirrors falls on photographic
+paper wound round a drum turned by clockwork, and a continuous
+record is thus obtained.</p>
+
+<p>3. Each galvanometer has a resistance of about 200 ohms,
+but is shunted by a resistance of only 2 ohms. The total effective
+resistances in the N.-S. and E.-W. lines are 225 and 348 ohms
+respectively. If i is the current recorded, L, g and s the resistances
+of the line, galvanometer and shunt respectively, then
+E, the difference of potential between the two earth plates, is
+given by</p>
+
+<p class="center">E = i (1 + g/s) {L + gs / (g + s)}.</p>
+
+<p class="noind">To calibrate the record, a Daniell cell is put in a circuit including
+1000 ohms and the three galvanometers as shunted.
+If i&prime; be the current recorded, e the E.M.F. of the cell, then
+e = i&prime; (1 + g/s) {1000 + 3gs / (g + s)}. Under the conditions at Parc
+Saint Maur we may write 2 for gs / (g + s), and 1.072 for e, and
+thence we have approximately E = 0.240 (i / i&prime;) for the N.-S. line,
+and E = &minus;0.371(i / i&prime;) for the E.-W. line.</p>
+
+<p>The method of standardization assumes a potential difference
+between earth plates which varies slowly enough to produce a
+practically steady current. There are several causes producing
+currents in a telegraph wire which do not satisfy this limitation.
+During thunderstorms surgings may arise, at least in overhead
+wires, without these being actually struck. Again, if the circuit
+includes a variable magnetic field, electric currents will be
+produced independently of any direct source of potential difference.
+In the third circuit at Parc Saint Maur, where no earth
+plates exist, the current must be mainly due to changes in the
+earth&rsquo;s vertical magnetic field, with superposed disturbances
+due to atmospheric electricity or aerial waves. Even in the
+other circuits, magnetic and atmospheric influences play some
+part, and when their contribution is important, the galvanometer
+deflection has an uncertain value. What a galvanometer records
+when traversed by a suddenly varying current depends on other
+things than its mere resistance.</p>
+
+<p>Even when the current is fairly steady, its exact significance
+is not easily stated. In the first place there is usually an appreciable
+E.M.F. between a plate and the earth in contact with it,
+and this E.M.F. may vary with the temperature and the dryness
+of the soil. Naturally one employs similar plates buried to the
+same depth at the two ends, but absolute identity and invariability
+of conditions can hardly be secured. In some cases, in
+short lines (<b>8</b>), there is reason to fear that plate E.M.F.&rsquo;s have
+been responsible for a good deal that has been ascribed to true
+earth currents. With deep earth plates, in dry ground, this
+source of uncertainty can, however, enter but little into the
+diurnal inequality.</p>
+
+<p>4. Another difficulty is the question of the resistance in the
+earth itself. A given E.M.F. between plates 10 m. apart may
+mean very different currents travelling through the earth,
+according to the chemical constitution and condition of the
+surface strata.</p>
+
+<p>According to Professor A. Schuster (<b>9</b>), if &rho; and &rho;&rsquo; be the
+specific resistances of the material of the wire and of the soil,
+the current i which would pass along an underground cable
+formed of actual soil, equal in diameter to the wire connecting
+the plates, is given by i = i&prime;&rho; / &rho;&prime;, where i&prime; is the observed current
+in the wire. As &rho;&rsquo; will vary with the depth, and be different at
+different places along the route, while discontinuities may arise
+from geological faults, water channels and so on, it is clear that
+even the most careful observations convey but a general idea
+as to the absolute intensity of the currents in the earth itself.
+In Schuster&rsquo;s formula, as in the formulae deduced for Parc Saint
+Maur, it is regarded as immaterial whether the wire connecting
+the plates is above or below ground. This view is in accordance
+with records obtained by Blavier (<b>3</b>) from two lines between
+Paris and Nancy, the one an air line, the other underground.</p>
+
+<p>5. The earliest quantitative results for the regular diurnal
+changes in earth currents are probably those deduced by Airy
+(<b>5</b>) from the records at Greenwich between 1865 and 1867.
+Airy resolved the observed currents from the two Greenwich
+lines in and perpendicular to the <i>magnetic</i> meridian (then about
+21° to the west of astronomical north). The information given
+by Airy as to the precise meaning of the quantities he terms
+&ldquo;magnetic tendency&rdquo; to north and to west is somewhat
+scanty, but we are unlikely to be much wrong in accepting his
+figures as proportional to the earth currents from magnetic
+east to west and from magnetic north to south respectively.
+Airy gives mean hourly values for each month of the year.
+The corresponding mean diurnal inequality for the whole
+year appears in Table 1., the unit being arbitrary. In
+every month the algebraic mean of the 24 hourly values
+represented a current from north to south in the magnetic
+meridian, and from east to west in the perpendicular direction;
+in the same arbitrary units used in Table I. the mean
+values of these two &ldquo;constant&rdquo; currents were respectively
+777 and 559.</p>
+
+<p>6. <i>Diurnal Variation.</i>&mdash;Probably the most complete records
+of diurnal variation are those discussed by Weinstein (<b>4</b>), which
+depend on several years&rsquo; records on lines from Berlin to Dresden
+and to Thorn. Relative to Berlin the geographical co-ordinates
+of the other two places are:</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcl">Thorn</td> <td class="tcl">0° 29&prime; N. lat. 5° 12&prime; E. long.</td></tr>
+<tr><td class="tcl">Dresden</td> <td class="tcl">1° 28&prime; S. lat. 0° 21&prime; E. long.</td></tr>
+</table>
+
+<p class="noind">Thus the Berlin-Dresden line was directed about 8½° east of south,
+and the Berlin-Thorn line somewhat more to the north of east.
+The latter line had a length about 2.18 times that of the former.
+The resistances in the two lines were made the same, so if we
+suppose the difference of potential between earth plates along
+a given direction to vary as their distance apart, the current
+observed in the Thorn-Berlin line has to be divided by 2.18 to be
+comparable with the other. In this way, resolving along and
+perpendicular to the geographical meridian, Weinstein gives
+as proportional to the earth currents from east to west and
+from south to north respectively</p>
+
+<p class="center">J = 0.147i&prime; + 0.435i, and J&prime; = 0.989i&prime; &minus; 0.100i,</p>
+
+<p><span class="pagenum"><a name="page815" id="page815"></a>815</span></p>
+
+<p>where i and i&rsquo; are the observed currents in the Thorn-Berlin and
+Dresden-Berlin lines respectively, both being counted positive
+when flowing towards Berlin.</p>
+
+<p>It is tacitly assumed that the average earth conductivity
+is the same between Berlin and Thorn as between Berlin and
+Dresden. It should also be noticed that local
+time at Berlin and Thorn differs by fully 20
+minutes, while the crests of the diurnal variations
+in <i>short</i> lines at the two places would probably
+occur about the same local time. The result
+is probably a less sharp occurrence of maxima
+and minima, and a relatively smaller range, than in a short
+line having the same orientation.</p>
+
+<p class="pt1 center sc">Table I.</p>
+
+<table class="ws f90" summary="Contents">
+<tr><td class="tccm allb cl" colspan="7">Mean Diurnal Inequalities for the year.</td> <td class="tccm allb cl" colspan="4">Numerical Values of resultant<br />current.</td></tr>
+
+<tr><td class="tccm allb" colspan="3">Greenwich.</td> <td class="tccm allb" colspan="4">Thorn-Berlin-Dresden.</td> <td class="tccm allb" colspan="4">Thorn-Berlin-Dresden.</td></tr>
+
+<tr><td class="tccm allb" rowspan="2">Hour.</td> <td class="tccm allb" rowspan="2">North<br />to<br />South<br />(Mag.)</td> <td class="tccm allb" rowspan="2">East<br />to<br />West<br />(Mag.)</td>
+  <td class="tccm allb" rowspan="2">Berlin<br />to<br />Dresden.</td> <td class="tccm allb" rowspan="2">Thorn<br />to<br />Berlin.</td>
+  <td class="tccm allb" rowspan="2">North<br />to<br />South<br />(Ast.)</td> <td class="tccm allb" rowspan="2">East<br />to<br />West<br />(Ast.)</td>
+  <td class="tccm allb" colspan="4">Mean hourly values from</td></tr>
+
+<tr><td class="tccm allb">Year.</td> <td class="tccm allb">Winter.</td> <td class="tccm allb">Equinox.</td> <td class="tccm allb">Summer.</td></tr>
+
+<tr><td class="tcc lb rb">1</td> <td class="tcr rb">&minus;94</td> <td class="tcr rb">&minus;41</td> <td class="tcr rb">&minus;17</td> <td class="tcr rb">&minus;13</td> <td class="tcr rb">&minus;20</td> <td class="tcr rb">&minus;10</td> <td class="tcr rb">81</td> <td class="tcr rb">94</td> <td class="tcr rb">51</td> <td class="tcr rb">98</td></tr>
+<tr><td class="tcc lb rb">2</td> <td class="tcr rb">&minus;68</td> <td class="tcr rb">&minus;24</td> <td class="tcr rb">&minus;6</td> <td class="tcr rb">&minus;13</td> <td class="tcr rb">&minus;9</td> <td class="tcr rb">&minus;11</td> <td class="tcr rb">84</td> <td class="tcr rb">115</td> <td class="tcr rb">39</td> <td class="tcr rb">97</td></tr>
+<tr><td class="tcc lb rb">3</td> <td class="tcr rb">&minus;44</td> <td class="tcr rb">&minus;8</td> <td class="tcr rb">&minus;1</td> <td class="tcr rb">&minus;1</td> <td class="tcr rb">&minus;1</td> <td class="tcr rb">&minus;1</td> <td class="tcr rb">84</td> <td class="tcr rb">113</td> <td class="tcr rb">31</td> <td class="tcr rb">108</td></tr>
+<tr><td class="tcc lb rb">4</td> <td class="tcr rb">&minus;18</td> <td class="tcr rb">+9</td> <td class="tcr rb">&minus;20</td> <td class="tcr rb">+15</td> <td class="tcr rb">&minus;17</td> <td class="tcr rb">+17</td> <td class="tcr rb">101</td> <td class="tcr rb">94</td> <td class="tcr rb">58</td> <td class="tcr rb">127</td></tr>
+<tr><td class="tcc lb rb">5</td> <td class="tcr rb">&minus;30</td> <td class="tcr rb">&minus;1</td> <td class="tcr rb">&minus;79</td> <td class="tcr rb">+21</td> <td class="tcr rb">&minus;74</td> <td class="tcr rb">+32</td> <td class="tcr rb">122</td> <td class="tcr rb">58</td> <td class="tcr rb">78</td> <td class="tcr rb">230</td></tr>
+<tr><td class="tcc lb rb">6</td> <td class="tcr rb">&minus;63</td> <td class="tcr rb">&minus;33</td> <td class="tcr rb">&minus;139</td> <td class="tcr rb">+5</td> <td class="tcr rb">&minus;136</td> <td class="tcr rb">+26</td> <td class="tcr rb">148</td> <td class="tcr rb">80</td> <td class="tcr rb">139</td> <td class="tcr rb">225</td></tr>
+<tr><td class="tcc lb rb">7</td> <td class="tcr rb">&minus;121</td> <td class="tcr rb">&minus;80</td> <td class="tcr rb">&minus;138</td> <td class="tcr rb">&minus;36</td> <td class="tcr rb">&minus;144</td> <td class="tcr rb">&minus;14</td> <td class="tcr rb">166</td> <td class="tcr rb">155</td> <td class="tcr rb">206</td> <td class="tcr rb">136</td></tr>
+<tr><td class="tcc lb rb">8</td> <td class="tcr rb">&minus;175</td> <td class="tcr rb">&minus;123</td> <td class="tcr rb">&minus;7</td> <td class="tcr rb">&minus;98</td> <td class="tcr rb">&minus;28</td> <td class="tcr rb">&minus;92</td> <td class="tcr rb">203</td> <td class="tcr rb">152</td> <td class="tcr rb">185</td> <td class="tcr rb">271</td></tr>
+<tr><td class="tcc lb rb">9</td> <td class="tcr rb">&minus;156</td> <td class="tcr rb">&minus;137</td> <td class="tcr rb">+249</td> <td class="tcr rb">&minus;156</td> <td class="tcr rb">+212</td> <td class="tcr rb">&minus;184</td> <td class="tcr rb">305</td> <td class="tcr rb">67</td> <td class="tcr rb">272</td> <td class="tcr rb">575</td></tr>
+<tr><td class="tcc lb rb">10</td> <td class="tcr rb">&minus;43</td> <td class="tcr rb">&minus;77</td> <td class="tcr rb">+540</td> <td class="tcr rb">&minus;184</td> <td class="tcr rb">+494</td> <td class="tcr rb">&minus;254</td> <td class="tcr rb">557</td> <td class="tcr rb">232</td> <td class="tcr rb">628</td> <td class="tcr rb">811</td></tr>
+<tr><td class="tcc lb rb">11</td> <td class="tcr rb">+82</td> <td class="tcr rb">+1</td> <td class="tcr rb">+722</td> <td class="tcr rb">&minus;165</td> <td class="tcr rb">+678</td> <td class="tcr rb">&minus;-263</td> <td class="tcr rb">728</td> <td class="tcr rb">411</td> <td class="tcr rb">885</td> <td class="tcr rb">887</td></tr>
+<tr><td class="tcc lb rb">Noon</td> <td class="tcr rb">+207</td> <td class="tcr rb">+66</td> <td class="tcr rb">+673</td> <td class="tcr rb">&minus;107</td> <td class="tcr rb">+642</td> <td class="tcr rb">&minus;200</td> <td class="tcr rb">675</td> <td class="tcr rb">441</td> <td class="tcr rb">848</td> <td class="tcr rb">735</td></tr>
+<tr><td class="tcc lb rb">1</td> <td class="tcr rb">+245</td> <td class="tcr rb">+94</td> <td class="tcr rb">+404</td> <td class="tcr rb">&minus;20</td> <td class="tcr rb">+395</td> <td class="tcr rb">&minus;79</td> <td class="tcr rb">400</td> <td class="tcr rb">284</td> <td class="tcr rb">510</td> <td class="tcr rb">406</td></tr>
+<tr><td class="tcc lb rb">2</td> <td class="tcr rb">+205</td> <td class="tcr rb">+113</td> <td class="tcr rb">+35</td> <td class="tcr rb">+55</td> <td class="tcr rb">+46</td> <td class="tcr rb">+47</td> <td class="tcr rb">98</td> <td class="tcr rb">68</td> <td class="tcr rb">103</td> <td class="tcr rb">125</td></tr>
+<tr><td class="tcc lb rb">3</td> <td class="tcr rb">+153</td> <td class="tcr rb">+97</td> <td class="tcr rb">&minus;261</td> <td class="tcr rb">+99</td> <td class="tcr rb">&minus;237</td> <td class="tcr rb">+132</td> <td class="tcr rb">272</td> <td class="tcr rb">136</td> <td class="tcr rb">355</td> <td class="tcr rb">324</td></tr>
+<tr><td class="tcc lb rb">4</td> <td class="tcr rb">+159</td> <td class="tcr rb">+108</td> <td class="tcr rb">&minus;397</td> <td class="tcr rb">+114</td> <td class="tcr rb">&minus;368</td> <td class="tcr rb">+167</td> <td class="tcr rb">404</td> <td class="tcr rb">218</td> <td class="tcr rb">503</td> <td class="tcr rb">492</td></tr>
+<tr><td class="tcc lb rb">5</td> <td class="tcr rb">+167</td> <td class="tcr rb">+118</td> <td class="tcr rb">&minus;391</td> <td class="tcr rb">+108</td> <td class="tcr rb">&minus;363</td> <td class="tcr rb">+160</td> <td class="tcr rb">397</td> <td class="tcr rb">206</td> <td class="tcr rb">453</td> <td class="tcr rb">532</td></tr>
+<tr><td class="tcc lb rb">6</td> <td class="tcr rb">+125</td> <td class="tcr rb">+95</td> <td class="tcr rb">&minus;311</td> <td class="tcr rb">+96</td> <td class="tcr rb">&minus;287</td> <td class="tcr rb">+137</td> <td class="tcr rb">319</td> <td class="tcr rb">176</td> <td class="tcr rb">333</td> <td class="tcr rb">446</td></tr>
+<tr><td class="tcc lb rb">7</td> <td class="tcr rb">+43</td> <td class="tcr rb">+55</td> <td class="tcr rb">&minus;237</td> <td class="tcr rb">+85</td> <td class="tcr rb">&minus;216</td> <td class="tcr rb">+115</td> <td class="tcr rb">247</td> <td class="tcr rb">180</td> <td class="tcr rb">250</td> <td class="tcr rb">312</td></tr>
+<tr><td class="tcc lb rb">8</td> <td class="tcr rb">&minus;22</td> <td class="tcr rb">+4</td> <td class="tcr rb">&minus;191</td> <td class="tcr rb">+74</td> <td class="tcr rb">&minus;173</td> <td class="tcr rb">+98</td> <td class="tcr rb">201</td> <td class="tcr rb">207</td> <td class="tcr rb">217</td> <td class="tcr rb">181</td></tr>
+<tr><td class="tcc lb rb">9</td> <td class="tcr rb">&minus;115</td> <td class="tcr rb">&minus;49</td> <td class="tcr rb">&minus;168</td> <td class="tcr rb">+59</td> <td class="tcr rb">&minus;153</td> <td class="tcr rb">+81</td> <td class="tcr rb">174</td> <td class="tcr rb">208</td> <td class="tcr rb">194</td> <td class="tcr rb">120</td></tr>
+<tr><td class="tcc lb rb">10</td> <td class="tcr rb">&minus;138</td> <td class="tcr rb">&minus;74</td> <td class="tcr rb">&minus;135</td> <td class="tcr rb">+40</td> <td class="tcr rb">&minus;125</td> <td class="tcr rb">+58</td> <td class="tcr rb">138</td> <td class="tcr rb">155</td> <td class="tcr rb">149</td> <td class="tcr rb">111</td></tr>
+<tr><td class="tcc lb rb">11</td> <td class="tcr rb">&minus;136</td> <td class="tcr rb">&minus;70</td> <td class="tcr rb">&minus;84</td> <td class="tcr rb">+18</td> <td class="tcr rb">&minus;79</td> <td class="tcr rb">+29</td> <td class="tcr rb">89</td> <td class="tcr rb">64</td> <td class="tcr rb">95</td> <td class="tcr rb">107</td></tr>
+<tr><td class="tcc lb rb bb">Midnight</td> <td class="tcr rb bb">&minus;147</td> <td class="tcr rb bb">&minus;80</td> <td class="tcr rb bb">&minus;43</td> <td class="tcr rb bb">&minus;2</td> <td class="tcr rb bb">&minus;43</td> <td class="tcr rb bb">+4</td> <td class="tcr rb bb">91</td> <td class="tcr rb bb">42</td> <td class="tcr rb bb">119</td> <td class="tcr rb bb">111</td></tr>
+</table>
+
+<p>It was found that the average current derived from a number
+of undisturbed days on either line might be regarded as made up
+of a &ldquo;constant part&rdquo; plus a regular diurnal inequality, the constant
+part representing the algebraic mean value of the 24 hourly
+readings. In both lines the constant part showed a decided
+alteration during the third year&mdash;changing sign in one line&mdash;in
+consequence, it is believed, of alterations made in the earth
+plates. The constant part was regarded as a plate effect, and was
+omitted from further consideration. Table I. shows in terms
+of an arbitrary unit&mdash;whose relation to that employed for
+Greenwich data is unknown&mdash;the diurnal inequality in the
+currents along the two lines, and the inequalities thence calculated
+for ideal lines in and perpendicular to the <i>geographical</i>
+meridian. Currents are regarded as positive when directed from
+Berlin to Dresden and from north to south, the opposite point
+of view to that adopted by Weinstein. The table also shows
+the mean <i>numerical</i> value of the resultant current (the &ldquo;constant&rdquo;
+part being omitted) for each hour of the day, for the year
+as a whole, and for winter (November to February), equinox
+(March, April, September, October) and summer (May to
+August). There is a marked double period in both the
+N.-S. and E.-W. currents. In both cases the numerically
+largest currents occur from 10 <span class="scs">A.M.</span> to noon, the directions
+then being from north to south and from west to east.
+The currents tend to die out and change sign about 2 <span class="scs">P.M.</span>,
+the numerical magnitude then rising again rapidly to 4 or
+5 <span class="scs">P.M.</span> The current in the meridian is notably the larger.
+The numerical values assigned to the resultant current are
+arithmetic means from the several months composing the season in
+question.</p>
+
+<p>7. The mean of the 24 hourly numerical values of the resultant current
+for each month of the year a deducible from Weinstein&rsquo;s data&mdash;the unit
+being the same as before&mdash;are given in Table II.</p>
+
+<p class="pt1 center"><span class="sc">Table II</span>.&mdash;<i>Mean Numerical Value of Resultant Current.</i></p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcc allb">Jan.</td> <td class="tcc allb">Feb.</td> <td class="tcc allb">March</td> <td class="tcc allb">April</td> <td class="tcc allb">May</td> <td class="tcc allb">June</td> <td class="tcc allb">July</td> <td class="tcc allb">Aug.</td> <td class="tcc allb">Sep.</td> <td class="tcc allb">Oct.</td> <td class="tcc allb">Nov.</td> <td class="tcc allb">Dec.</td></tr>
+<tr><td class="tcc allb">152</td> <td class="tcc allb">211</td> <td class="tcc allb">293</td> <td class="tcc allb">328</td> <td class="tcc allb">313</td> <td class="tcc allb">314</td> <td class="tcc allb">337</td> <td class="tcc allb">300</td> <td class="tcc allb">258</td> <td class="tcc allb">235</td> <td class="tcc allb">165</td> <td class="tcc allb">132</td></tr>
+</table>
+
+<p>There is thus a conspicuous minimum at mid-winter,
+and but little difference between the monthly
+means from April to August. This is closely
+analogous to what is seen in the daily range of
+the magnetic elements in similar latitudes (see
+<span class="sc"><a href="#artlinks">Magnetism, Terrestrial</a></span>). There is also considerable
+resemblance between the curve whose ordinates
+represent the diurnal inequality in the current
+passing from north to south, and the curve showing
+the hourly change in the westerly component of the
+horizontal magnetic force in similar European
+latitudes.</p>
+
+<p>8. <i>Relations with Sun-spots, Auroras and Magnetic
+Storms.</i>&mdash;Weinstein gives curves representing the
+mean diurnal inequality for separate years. In
+both lines the diurnal amplitudes were notably
+smaller in the later years which were near
+sun-spot minimum. This raises a presumption that
+the regular diurnal earth currents, like the
+ranges of the magnetic elements, follow the
+11-year sun-spot period. When we pass to the large
+and irregular earth currents, which are of
+practical interest in telegraphy, there is every
+reason to suppose that the sun-spot period
+applies. These currents are always accompanied by
+magnetic disturbances, and when specially striking
+by brilliant aurora. One most conspicuous example
+of this occurred in the end of August and
+beginning of September 1859. The magnetic
+disturbances recorded were of almost unexampled
+size and rapidity, the accompanying aurora was
+extraordinarily brilliant, and E.M.F.&rsquo;s of 700 and
+800 volts are said to have been reached on
+telegraph lines 500 to 600 km. long. It is
+doubtful whether the disturbances of 1859 have
+been equalled since, but earth current voltages of
+the order of 0.5 volts per mile have been recorded
+by various authorities, <i>e.g.</i> Sir W.H. Preece
+(<b>10</b>).</p>
+
+<p>It was the practice for several years to publish
+in the <i>Ann. du bureau central météorologique</i>
+synchronous magnetic and earth current curves from
+Parc Saint Maur corresponding to the chief
+disturbances of the year. In most cases there is a
+marked similarity between the curve of magnetic
+declination and that of the north-south earth
+current. At times there is also a distinct
+resemblance between the horizontal force magnetic
+curve and that of the east-west earth current, but
+exceptions to this are not infrequent. Similar
+phenomena appear in synchronous Greenwich records
+published by Airy in 1868; these show a close
+accordance between the horizontal force curves and
+those of the currents from magnetic east to west.
+Originally it was supposed by Airy that whilst
+rapid movements in the declination and north-south
+current curves sometimes
+<span class="pagenum"><a name="page816" id="page816"></a>816</span>
+occurred simultaneously, there was a distinct tendency for the
+latter to precede the former. More recent examinations of the
+Greenwich records by W. Ellis (<b>11</b>), and of the Parc St Maur
+curves by Moureaux, have not confirmed this result, and it is now
+believed that the two phenomena are practically simultaneous.</p>
+
+<p>There has also been a conflict of views as to the connexion
+between magnetic and earth current disturbances. Airy&rsquo;s
+observations tended to suggest that the earth current was the
+primary cause, and the magnetic disturbance in considerable
+part at least its effect. Others, on the contrary, have supposed
+earth currents to be a direct effect of changes in the earth&rsquo;s
+magnetic field. The prevailing view now is that both the
+magnetic and the earth current disturbances are due to electric
+currents in the upper atmosphere, these upper currents becoming
+visible at times as aurora.</p>
+
+<p>9. There seems some evidence that earth currents can be
+called into existence by purely local causes, notably difference
+of level. Thus K.A. Brander (<b>12</b>) has observed a current
+flowing constantly for a good many days from Airolo (height
+1160 metres) to the Hospice St Gotthard (height 2094 metres).
+In an 8-km. line from Resina to the top of Vesuvius L. Palmieri
+(<b>13</b>)&mdash;observing in 1889 at three-hour intervals from 9 <span class="scs">A.M.</span> to
+9 <span class="scs">P.M.</span>&mdash;always found a current running uphill so long as the
+mountain was quiet. On a long line from Vienna to Graz A.
+Baumgartner (<b>14</b>) found that the current generally flowed from
+both ends towards intervening higher ground during the day,
+but in the opposite directions at night. During a fortnight in
+September and October 1885 hourly readings were taken of the
+current in the telegraph cable from Fort-William to Ben Nevis
+Observatory, and the results were discussed by H.N. Dickson
+(<b>15</b>), who found a marked preponderance of currents up the line
+to the summit. The recorded mean data, otherwise regarded,
+represent a &ldquo;constant&rdquo; current, equal to 29 in the arbitrary
+units employed by Dickson, flowing up the line, together with
+the following diurnal inequality, + denoting current towards
+Fort-William (<i>i.e.</i> down the hill, and nearly east to west).</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tcc rb">Hour</td> <td class="tcc rb">1</td> <td class="tcc rb">2</td> <td class="tcc rb">3</td> <td class="tcc rb">4</td> <td class="tcc rb">5</td> <td class="tcc rb">6</td> <td class="tcc rb">7</td> <td class="tcc rb">8</td> <td class="tcc rb">9</td> <td class="tcc rb">10</td> <td class="tcc rb">11</td> <td class="tcc">12</td></tr>
+
+<tr><td class="tcr rb pt1"><span class="scs">A.M.</span></td> <td class="tcr rb pt1">&minus;21</td> <td class="tcr rb pt1">&minus;41</td> <td class="tcr rb pt1">+13</td> <td class="tcr rb pt1">+23</td> <td class="tcr rb pt1">+55</td> <td class="tcr rb pt1">&minus;3</td> <td class="tcr rb pt1">+25</td> <td class="tcr rb pt1">&minus;32</td> <td class="tcr rb pt1">&minus;59</td> <td class="tcr rb pt1">&minus;62</td> <td class="tcr rb pt1">&minus;46</td> <td class="tcr pt1">+6</td></tr>
+<tr><td class="tcr rb"><span class="scs">P.M.</span></td> <td class="tcr rb">+24</td> <td class="tcr rb">+18</td> <td class="tcr rb">+115</td> <td class="tcr rb">+18</td> <td class="tcr rb">+75</td> <td class="tcr rb">&minus;5</td> <td class="tcr rb">+50</td> <td class="tcr rb">&minus;9</td> <td class="tcr rb">&minus;56</td> <td class="tcr rb">&minus;37</td> <td class="tcr rb">&minus;28</td> <td class="tcr">&minus;34</td></tr>
+</table>
+
+<p>There is thus a diurnal inequality, which is by no means very
+irregular considering the limited number of days, and it bears
+at least a general resemblance to that shown by Weinstein&rsquo;s
+figures for an east-west line in Germany. This will serve to
+illustrate the uncertainties affecting these and analogous observations.
+A constant current in one direction may arise in whole or
+part from plate E.M.F.&rsquo;s; a current showing a diurnal inequality
+will naturally arise between <i>any</i> two places some distance apart
+whether they be at different levels or not. Finally, when
+records are taken only for a short time, doubts must arise as
+to the generality of the results. During the Ben Nevis observations,
+for instance, we are told that the summit was almost
+constantly enveloped in fog or mist. By having three earth
+plates in the same vertical plane, one at the top of a mountain,
+the others at opposite sides of it, and then observing the currents
+between the summit and each of the base stations, as well as
+directly between the base stations&mdash;during an adequate number
+of days representative of different seasons of the year and
+different climatic conditions&mdash;many uncertainties would soon
+be removed.</p>
+
+<p>10. <i>Artificial Currents.</i>&mdash;The great extension in the applications
+of electricity to lighting, traction and power transmission,
+characteristic of the end of the 19th century, has led to the
+existence of large artificial earth currents, which exert a disturbing
+influence on galvanometers and magnetic instruments, and
+also tend to destroy metal pipes. In the former case, whilst
+the disturbance is generally loosely assigned to stray or &ldquo;vagabond&rdquo;
+earth currents, this is only partly correct. The currents
+used for traction are large, and even if there were a perfectly
+insulated return there would be a considerable resultant magnetic
+field at distances from the track which were not largely in
+excess of the distance apart of the direct and return currents
+(<b>16</b>). At a distance of half a mile or more from an electric tram
+line the disturbance is usually largest in magnetographs recording
+the vertical component of the earth&rsquo;s field. The magnets are
+slightly displaced from the position they would occupy if undisturbed,
+and are kept in continuous oscillation whilst the
+trams are running (<b>17</b>). The extent of the oscillation depends
+on the damping of the magnets.</p>
+
+<p>The distance from an electric tram line where the disturbance
+ceases to be felt varies with the system adopted. It also depends
+on the length of the line and its subdivision into sections, on
+the strength of the currents supplied, the amount of leakage, the
+absence or presence of &ldquo;boosters,&rdquo; and finally on the sensitiveness
+of the magnetic instruments. At the U.S. Coast and
+Geodetic Survey&rsquo;s observatory at Cheltenham the effect of the
+Washington electric trams has been detected by highly sensitive
+magnetographs, though the nearest point of the line is 12 m.
+away (<b>18</b>). Amongst the magnetic observatories which have
+suffered severely from this cause are those at Toronto, Washington
+(Naval Observatory), Kew, Paris (Parc St Maur), Perpignan,
+Nice, Lisbon, Vienna, Rome, Bombay (Colaba) and Batavia.
+In some cases magnetic observations have been wholly suspended,
+in others new observatories have been built on more remote sites.</p>
+
+<p>As regards damage to underground pipes, mainly gas and
+water pipes, numerous observations have been made, especially
+in Germany and the United States. When electric tramways
+have uninsulated returns, and the potential of the rails is allowed
+to differ considerably from that of the earth, very considerable
+currents are found in neighbouring pipes. Under these conditions,
+if the joints between contiguous pipes forming a main
+present appreciable resistance, whilst the surrounding earth
+through moisture or any other cause is a fair conductor, current
+passes locally from the pipes to the earth causing electrolytic
+corrosion of the pipes. Owing to the diversity of interests
+concerned, the extent of the damage thus caused has been very
+variously estimated. In some instances it has been so considerable
+as to be the alleged cause of the ultimate failure of water
+pipes to stand the pressure they are
+exposed to.</p>
+
+<div class="condensed">
+<p><span class="sc">Bibliography.</span>&mdash;See Svante August
+Arrhenius, <i>Lehrbuch der kosmischen Physik</i>
+(Leipzig, 1903), pp. 984-990. For lists of references see J.E.
+Burbank, <i>Terrestrial Magnetism</i>, vol. 10 (1905), p. 23, and
+P. Bachmetjew (<b>8</b>). For papers descriptive of corrosion of pipes,
+&amp;c., by artificial currents see <i>Science Abstracts</i> (in recent years
+in the volumes devoted to engineering) under the heading &ldquo;Traction,
+Electric; Electrolysis.&rdquo; The following are the references
+in the text:&mdash;(<b>1</b>) <i>Phil. Trans. R.S.</i> for 1849, pt. i. p. 61; (<b>2</b>) <i>Phil.
+Trans. R.S.</i> vol. 151 (1861), p. 89, and vol. 152 (1862), p. 203; (<b>3</b>)
+<i>Étude des courants telluriques</i> (Paris, 1884); (<b>4</b>) <i>Die Erdströme im
+deutschen Reichstelegraphengebiet</i> (Braunschweig, 1900); (<b>5</b>) <i>Phil.
+Trans. R.S.</i> vol. 158 (1868), p. 465, and vol. 160 (1870), p. 215; (<b>6</b>)
+<i>Mém. de l&rsquo;Académie St-Pétersbourg</i>, t. 31, No. 12 (1883); (<b>7</b>) T.
+Moureaux, <i>Ann. du Bureau Central Mét.</i> (Année 1893), 1 Mem. p.
+B 23; (<b>8</b>) P. Bachmetjew, <i>Mém. de l&rsquo;Académie St-Pétersbourg</i>, vol. 12,
+No. 3 (1901); (<b>9</b>) <i>Terrestrial Magnetism</i>, vol. 3 (1898), p. 130; (<b>10</b>)
+<i>Journal Tel. Engineers</i> (1881); (<b>11</b>) <i>Proc. R.S.</i> vol. 52 (1892), p. 191;
+(<b>12</b>) <i>Akad. Abhandlung</i> (Helsingfors, 1888); (<b>13</b>) <i>Acad. Napoli Rend.</i>
+(1890), and <i>Atti</i> (1894, 1895); (<b>14</b>) <i>Pogg. Ann.</i> vol. 76, p. 135; (<b>15</b>)
+<i>Proc. R.S.E.</i> vol. 13, p. 530; (<b>16</b>) A. Rücker, <i>Phil. Mag.</i> 1 (1901), p.
+423, and R.T. Glazebrook, <i>ibid.</i> p. 432; (<b>17</b>) J. Edler, <i>Elektrotech.
+Zeit.</i> vol. 20 (1899); (<b>18</b>) L.A. Bauer, <i>Terrestrial Magnetism</i>, vol. 11
+(1906), p. 53.</p>
+</div>
+<div class="author">(C. Ch.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARTH-NUT,<a name="ar43" id="ar43"></a></span> the English name for a plant known botanically
+as <i>Conopodium denudatum</i> (or <i>Bunium flexuosum</i>), a member of
+the natural order Umbelliferae, which has a brown tuber-like
+root-stock the size of a chestnut. It grows in woods and fields,
+has a slender flexuous smooth stem 2 to 3 ft. high, much-divided
+leaves, and small white flowers in many-rayed terminal compound
+umbels. Boswell Syme, in <i>English Botany</i>, iv. 114, says: &ldquo;The
+common names of this plant in England are various. It is
+known as earth-nut, pig-nut, ar-nut, kipper-nut, hawk-nut,
+jar-nut, earth-chestnut and ground-nut. Though really excellent
+in taste and unobjectionable as food, it is disregarded
+in England by all but pigs and children, both of whom
+appreciate it and seek eagerly for it.&rdquo; Dr Withering describes
+the roots as little inferior to chestnuts. In Holland
+<span class="pagenum"><a name="page817" id="page817"></a>817</span>
+and elsewhere on the continent of Europe they are more
+generally eaten.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARTH PILLAR,<a name="ar44" id="ar44"></a></span> a pillar of soft rock, or earth, capped by
+some harder material that has protected it from denudation.
+The &ldquo;bad lands&rdquo; of western North America furnish numerous
+examples. Here &ldquo;the formations are often beds of sandstone
+or shale alternating with unindurated beds of clay. A semi-arid
+climate where the precipitation is much concentrated
+seems to be most favourable to the development of this type
+of formation.&rdquo; The country round the Dead Sea, where loose
+friable sandy clay is capped by harder rock, produces &ldquo;bad-land&rdquo;
+topography. The cap of hard rock gives way at the joints, and
+the water making its way downwards washes away the softer
+material directly under the cracks, which become wider, leaving
+isolated columns of clay capped with hard sandstone or limestone.
+These become smaller and fewer as denudation proceeds, the
+pillars standing a great height at times, until finally they all
+disappear.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EARTHQUAKE.<a name="ar45" id="ar45"></a></span> Although the terrible effects which often
+accompany earthquakes have in all ages forced themselves upon
+the attention of man, the exact investigation of seismic phenomena
+dates only from the middle of the 19th century. A new science
+has been thus established under the name of <i>seismology</i> (Gr.
+<span class="grk" title="seismos">&#963;&#949;&#953;&#963;&#956;&#972;&#962;</span>, an earthquake).</p>
+
+<p><i>History.</i>&mdash;Accounts of earthquakes are to be found scattered
+through the writings of many ancient authors, but they are, for
+the most part, of little value to the seismologist. There is a
+natural tendency to exaggeration in describing such phenomena,
+sometimes indeed to the extent of importing a supernatural
+element into the description. It is true that attempts were made
+by some ancient writers on natural philosophy to offer a rational
+explanation of earthquake phenomena, but the hypotheses
+which their explanations involved are, as a rule, too fanciful to
+be worth reproducing at the present day. It is therefore unnecessary
+to dwell upon the references to seismic phenomena
+which have come down to us in the writings of such historians
+and philosophers as Thucydides, Aristotle and Strabo, Seneca,
+Livy and Pliny. Nor is much to be gleaned from the pages of
+medieval and later writers on earthquakes, of whom the most
+notable are Fromondi (1527), Maggio (1571) and Travagini
+(1679). In England, the earliest work worthy of mention is
+Robert Hooke&rsquo;s <i>Discourse on Earthquakes</i>, written in 1668, and
+read at a later date before the Royal Society. This discourse,
+though containing many passages of considerable merit, tended
+but little to a correct interpretation of the phenomena in question.
+Equally unsatisfactory were the attempts of Joseph Priestley
+and some other scientific writers of the 18th century to connect
+the cause of earthquakes with electrical phenomena. The great
+earthquake of Lisbon in 1755 led the Rev. John Michell, professor
+of mineralogy at Cambridge, to turn his attention to the subject;
+and in 1760 he published in the <i>Philosophical Transactions</i> a
+remarkable essay on the Cause and Phenomena of Earthquakes.
+A suggestion of much scientific interest was made by Thomas
+Young, when in his <i>Lectures on Natural Philosophy</i>, published
+in 1807, he remarked that an earthquake &ldquo;is probably propagated
+through the earth nearly in the same manner as a noise
+is conveyed through the air.&rdquo; The recognition of the fact that
+the seismologist has to deal with the investigation of wave-motion
+in solids lies at the very base of his science. In 1846
+Robert Mallet communicated to the Royal Irish Academy his
+first paper &ldquo;On the Dynamics of Earthquakes&rdquo;; and in the
+following year W. Hopkins, of Cambridge, presented to the
+British Association a valuable report in which earthquake
+phenomena were discussed in some detail. Mallet&rsquo;s labours
+were continued for many years chiefly in the form of Reports to
+the British Association, and culminated in his great work on
+the Neapolitan earthquake of 1857. An entirely new impetus,
+however, was given to the study of earthquakes by an energetic
+body of observers in Japan, who commenced their investigations
+about the year 1880, mainly through the influence of Prof.
+John Milne, then of Tokyo. Their work, carried on by means of
+new instruments of precision, and since taken up by observers
+in many parts of the world, has so extended our knowledge of
+earthquake-motion that seismology has now become practically
+a new department of physical science.</p>
+
+<p>It is hardly too much to say, however, that the earliest
+systematic application of scientific principles to the study of the
+effects of an earthquake was made by Mallet in his investigation
+of the Neapolitan earthquake mentioned above. It is true, the
+great Calabrian earthquake of 1783 had been the subject of
+careful inquiry by the Royal Academy of Naples, as also by
+Deodat Dolomieu and some other scientific authorities; but in
+consequence of the misconception which at that time prevailed
+with regard to the nature of seismic activity, the results of the
+inquiry, though in many ways interesting, were of very limited
+scientific value. It was reserved for Mallet to undertake for
+the first time an extensive series of systematic observations in
+an area of great seismic disturbance, with the view of explaining
+the phenomena by the application of the laws of wave-motion.</p>
+
+<p>The &ldquo;Great Neapolitan Earthquake,&rdquo; by which more than
+12,300 lives were lost, was felt in greater or less degree over
+all Italy south of the parallel of 42°, and has been
+regarded as ranking third in order of severity among the
+<span class="sidenote">Neapolitan earthquake, 1857.</span>
+recorded earthquakes of Europe. The principal shock
+occurred at about 10 <span class="scs">P.M.</span> on the 16th of December
+1857; but, as is usually the case, it had been preceded by minor
+disturbances and was followed by numerous after-shocks which
+continued for many months. Early in 1858, aided by a grant
+from the Royal Society, Mallet visited the devastated districts,
+and spent more than two months in studying the effects of the
+catastrophe, especially examining, with the eye of an engineer,
+the cracks and ruins of the buildings. His voluminous report
+was published in 1862, and though his methods of research and
+his deductions have in many cases been superseded by the
+advance of knowledge, the report still remains a memorable
+work in the history of seismology.</p>
+
+<p>Much of Mallet&rsquo;s labour was directed to the determination of
+the position and magnitude of the subterranean source from
+which the vibratory impulses originated. This is known variously
+as the <i>seismic centre</i>, <i>centrum</i>, <i>hypocentre</i>, <i>origin</i> or <i>focus</i>. It
+is often convenient to regard this centre theoretically as a point,
+but practically it must be a locus or space of three dimensions,
+which in different cases varies much in size and shape, and may
+be of great magnitude. That part of the surface of the earth
+which is vertically above the centre is called the <i>epicentre</i>; or,
+if of considerable area, the epicentral or epifocal tract. A
+vertical line joining the epicentre and the focus was termed by
+Mallet the <i>seismic vertical</i>. He calculated that in the case of the
+Neapolitan earthquake the focal cavity was a curved lamelliform
+fissure, having a length of about 10 m. and a height of about
+3½ m., whilst its width was inconsiderable. The central point
+of this fissure, the theoretical seismic centre, he estimated to
+have been at a depth of about 6½ m. from the surface. Dr C.
+Davison, in discussing Mallet&rsquo;s data, was led to the conclusion
+that there were two distinct foci, possibly situated on a fault,
+or plane of dislocation, running in a north-west and south-east
+direction. Mallet located his epicentre near the village of
+Caggiano, not far from Polla, while the other seems to have been
+in the neighbourhood of Montemurro, about 25 m. to the south-east.</p>
+
+<p>The intensity, or violence, of an earthquake is greatest in or
+near the epicentre, whence it decreases in all directions. A line
+drawn through points of equal intensity forms a curve round the
+epicentre known as an <i>isoseist</i>, an <i>isoseismal</i> or an <i>isoseismic
+line</i>. If the intensity declined equally in all directions the
+isoseismals would be circles, but as this is rarely if ever the case
+in nature they usually become ellipses and other closed curves.
+The tract which is most violently shaken was termed by Mallet
+the <i>meizoseismic area</i>, whilst the line of maximum destruction
+is known as the <i>meizoseismic line</i>. That isoseismal along which
+the decline of energy is most rapid was called by K. von Seebach
+a <i>pleistoseist</i>.</p>
+
+<p>In order to determine the position of the seismic centre, Mallet
+made much use of the cracks in damaged buildings, especially
+<span class="pagenum"><a name="page818" id="page818"></a>818</span>
+in walls of masonry, holding that the direction of such fractures
+must generally be at right angles to that in which the normal
+earthquake-wave reached them. In this way he obtained the
+&ldquo;angle of emergence&rdquo; of the wave. He also assumed that
+free-falling bodies would be overthrown and projected in the
+direction of propagation of the wave, so that the epicentre might
+immediately be found from the intersection of such directions.
+These data are, however, subject to much error, especially
+through want of homogeneity in the rocks, but Mallet&rsquo;s work
+was still of great value.</p>
+
+<p>A different method of ascertaining the depth of the focus
+was adopted by Major C.E. Dutton in his investigation of the
+Charleston earthquake of the 31st of August 1886
+for the U.S. Geological Survey. This catastrophe
+<span class="sidenote">Charleston earthquake, 1886.</span>
+was heralded by shocks of greater or less severity a
+few days previously at Summerville, a village 22 m.
+north-west of Charleston. The great earthquake occurred at
+9.51 <span class="scs">P.M.</span>, standard time of the 75th meridian, and in about
+70 seconds almost every building in Charleston was more or
+less seriously damaged, while many lives were lost. The
+epicentral tract was mainly a forest region with but few
+buildings, and the principal records of seismological value were
+afforded by the lines of railway which traversed the disturbed
+area. In many places these rails were flexured and dislocated.
+Numerous fissures opened in the ground, and many of these
+discharged water, mixed sometimes with sand and silt, which
+was thrown up in jets rising in some cases to a height of 20 ft.
+Two epicentres were recognized&mdash;one near Woodstock station
+on the South Carolina railway, and the other, being the centre
+of a much smaller tract, about 14 m. south-west of the first and
+near the station of Rantowles on the Charleston and Savannah
+line. Around these centres and far away isoseismal lines were
+drawn, the relative intensity at different places being roughly
+estimated by the effects of the catastrophe on various structures
+and natural objects, or, where visible records were wanting,
+by personal evidence, which is often vague and variable. The
+Rossi-Forel scale was adopted. This is an arbitrary scale
+formulated by Professor M.S. de Rossi, of Rome, and Dr F.A.
+Forel, of Geneva, based mostly on the ordinary phenomena
+observed during an earthquake, and consisting of ten degrees,
+of which the lowest is the feeblest, viz. I. Microseismic shock;
+II. Extremely feeble shock; III. Very feeble shock; IV.
+Feeble; V. Shock of moderate intensity; VI. Fairly strong
+shock; VII. Strong shock; VIII. Very strong shock; IX.
+Extremely strong shock; X. Shock of extreme intensity.
+Other conventional scales, some being less detailed, have been
+drawn up by observers in such earthquake-shaken countries
+as Italy and Japan. A curve, or theoretical isoseismal, drawn
+through certain points where the decline of intensity on receding
+from the epicentre seems to be greatest was called by Dutton
+an &ldquo;index-circle&rdquo;; and it can be shown that the radius of such
+a circle multiplied by the square root of 3 gives the focal depth
+theoretically. In this way it was computed that in the Charleston
+earthquake the origin under Woodstock must have had a depth
+of about 12 m. and that near Rantowles a depth of nearly 8 m.
+The determination of the index-circle presents much difficulty,
+and the conclusions must be regarded as only approximate.</p>
+
+<p>It is probable, according to R.D. Oldham, that local
+earthquakes may originate in the &ldquo;outer skin&rdquo; of the earth,
+whilst a large world-shaking earthquake takes its origin in the
+deeper part of the &ldquo;crust,&rdquo; whence such a disturbance is termed a
+<i>bathyseism</i>. Large earthquakes may have very extended origins,
+with no definite centre, or with several foci.</p>
+
+<p>The gigantic disaster known as the &ldquo;Great Indian Earthquake,&rdquo;
+which occurred on the 12th of June 1897, was the subject of
+careful investigation by the Geological Survey of
+India and was described in detail by the superintendent,
+<span class="sidenote">Great Indian earthquake, 1897.</span>
+R.D. Oldham. It is sometimes termed
+the Assam earthquake, since it was in that province
+that the effects were most severe, but the shocks
+were felt over a large part of India, and indeed far beyond its
+boundaries. Much of the area which suffered most disturbance
+was a wild country, sparsely populated, with but few buildings
+of brick or stone from which the violence of the shocks could
+be estimated. The epicentral tract was of great size, having
+an estimated area of about 6000 sq. m., but the mischief was
+most severe in the neighbourhood of Shillong, where the
+stonework of bridges, churches and other buildings was absolutely
+levelled to the ground. After the main disturbance,
+shocks of greater or less severity continued at intervals for many
+weeks. It is supposed that this earthquake was connected with
+movement of subterranean rock-masses of enormous magnitude
+along a great thrust-plane, or series of such planes, having a
+length of about 200 m. and a maximum breadth of not less than
+50 m. It is pointed out by Oldham that this may be compared
+for size with the great Faille du Midi in Belgium, which is known
+to extend for a distance of 120 m. The depth of the principal
+focus, though not actually capable of determination, was probably
+less than 5 m. from the surface. From the focus many
+secondary faults and fractures proceeded, some reaching the
+surface of the ground. Enormous landslips accompanied the
+earthquake, and as an indirect effect of these slides the form of
+the water-courses became in certain cases modified. Permanent
+changes of level were also observed.</p>
+
+<p>Eight years after the great Assam earthquake India was
+visited by another earthquake, which, though less intense,
+resulted in the loss of about 20,000 lives. This catastrophe
+is known as the Kangra earthquake, since its
+<span class="sidenote">Kangra earthquake, 1905.</span>
+centre seems to have been located in the Kangra
+valley, in the north-west Himalaya. It occurred on
+the 4th of April 1905, and the first great shocks were felt in the
+chief epifocal district at about 6.9 a.m., Madras time. Although
+the tract chiefly affected was around Kangra and Dharmsala,
+there was a subordinate epifocal tract in Dehra Dun and the
+neighbourhood of Mussoorie, whilst the effects of the earthquake
+extended in slight measure to Lahore and other cities of the
+plain. It is estimated that the earthquake was felt over an area of
+about 1,625,000 m. Immediately after the calamity a scientific
+examination of its effects was made by the Geological Survey
+of India, and a report was drawn up by the superintendent,
+C.S. Middlemiss.</p>
+
+<p>The great earthquake, which, with the subsequent fire, wrought
+such terrible destruction in and around San Francisco on the 18th
+of April 1906, was the most disastrous ever recorded in
+California. It occurred between 10 and 15 minutes
+<span class="sidenote">California earthquake, 1906.</span>
+after 5 <span class="scs">A.M.</span>, standard time of the 120th meridian.
+The moment at which the disaster began and the
+duration of the shock varied at different localities in the great
+area over which the earthquake was felt. At San Francisco
+the main shock lasted rather more than one minute.</p>
+
+<p>According to the official Report, the earthquake was due
+to rupture and movement along the plane of the San Andreas
+fault, one of a series which runs for several hundred miles
+approximately in a N.W. and S.E. direction near the coast
+line. Evidence of fresh movement along this plane of dislocation
+was traced for a distance of 190 m. from San Juan
+on the south to Point Arena on the north. There the trace of
+the fault is lost beneath the sea, but either the same fault or
+another appears 75 m. to the north at Point Delgada. The belt
+of disturbed country is notoriously unstable, and part of the
+fault had been known as the &ldquo;earthquake crack.&rdquo; The direction
+is marked by lines of straight cliffs, long ponds and narrow
+depressions, forming a Rift, or old line of seismic disturbance.
+According to Dr G.K. Gilbert the earthquake zone has a length
+of 300 or 400 m. The principal displacement of rock, in 1906,
+was horizontal, amounting generally to about 10 ft. (maximum
+21 ft.), but there was also locally a slight vertical movement,
+which towards the north end of the fault reached 3 ft. Movement
+was traced for a distance of about 270 m., and it is estimated
+that at least 175,000 sq. m. of country must have been disturbed.
+In estimating the intensity of the earthquake in San Francisco
+a new scale was introduced by H.O. Wood. The greatest
+structural damage occurred on soft alluvial soil and &ldquo;made
+ground.&rdquo; Most of the loss of property in San Francisco was
+<span class="pagenum"><a name="page819" id="page819"></a>819</span>
+due to the terrible fire which followed the earthquake and was
+beyond control owing to the destruction of the system of water-supply.</p>
+
+<p>Immediately after the catastrophe a California Earthquake
+Investigation Committee was appointed by the governor of
+the state; and the American Association for the Advancement
+of Science afterwards instituted a Seismological Committee.
+The elaborate Report of the State Investigation Committee,
+by the chairman, Professor A.C. Lawson, was published in 1908.</p>
+
+<p>On the 17th of August 1906 a disastrous earthquake occurred
+at Valparaiso, and the year 1906 was marked generally by
+exceptional seismic activity.</p>
+
+<p>The Jamaica earthquake of the 14th of January 1907 appears
+to have accompanied movement of rock along an east and west
+fracture or series of fractures under the sea a few miles from the
+city of Kingston. The statue of Queen Victoria at Kingston
+was turned upon its pedestal the eighth of a revolution.</p>
+
+<p>A terrible earthquake occurred in Calabria and Sicily on
+December 28, 1908, practically destroying Messina and Reggio.
+According to the official returns the total loss of life
+was 77,283. Whilst the principal centre seems to
+<span class="sidenote">Messina earthquake, 1908.</span>
+have been in the Strait of Messina, whence the disturbance
+is generally known as the Messina earthquake,
+there were independent centres in the Calabrian peninsula,
+a country which had been visited by severe earthquakes not
+long previously, namely on September 8, 1905, and October
+23, 1907. The principal shock of the great Messina earthquake
+of 1908 occurred at 5.21 <span class="scs">A.M.</span> (4.21 Greenwich time), and had a
+duration of from 30 to 40 seconds. Neither during nor immediately
+before the catastrophe was there any special volcanic
+disturbance at Etna or at Stromboli, but it is believed that there
+must have been movement along a great plane of weakness in
+the neighbourhood of the Strait of Messina, which has been
+studied by E. Cortese. The sea-floor in the strait probably
+suffered great disturbance, resulting in the remarkable movement
+of water observed on the coast. At first the sea retired,
+and then a great wave rolled in, followed by others generally
+of decreasing amplitude, though at Catania the second was said
+to have been greater than the first. At Messina the height of
+the great wave was 2.70 metres, whilst at Ali and Giardini it
+reached 8.40 metres and at San Alessio as much as 11.7 metres.
+At Malta the tide-gauge recorded a wave of 0.91 metre. The
+depth of the chief earthquake-centre was estimated by Dr E.
+Oddone at about 9 kilometres. The earthquake and accompanying
+phenomena were studied also by Professor A. Riccò, Dr M.
+Baratta and Professor G. Platania and by Dr F. Omori of Tokyo.
+After the great disturbance, shocks continued to affect the region
+intermittently for several months. In certain respects the
+earthquake of 1908 presented much resemblance to the great
+Calabrian catastrophe of 1783.</p>
+
+<p>It has been proposed by R.D. Oldham that the disturbance
+which causes the fracture and permanent displacement of the
+rocks during an earthquake should be called an &ldquo;earthshake,&rdquo;
+leaving the term earthquake especially for the vibratory motion.
+The movement of the earthquake is molecular, whilst that of
+the earthshake is molar. Subsequently he suggested the terms
+<i>mochleusis</i> and <i>orchesis</i> (<span class="grk" title="mochleuô">&#956;&#959;&#967;&#955;&#941;&#965;&#969;</span>, I heave; <span class="grk" title="orcheomai">&#8000;&#961;&#967;&#941;&#959;&#956;&#945;&#953;</span>, I dance),
+to denote respectively the molar and the molecular movement,
+retaining the word earthquake for use in its ordinary sense.</p>
+
+<p>In most earthquakes the proximate cause is generally regarded
+as the fracture and sudden movement of underground rock-masses.
+Disturbances of this type are known as &ldquo;tectonic&rdquo;
+earthquakes, since they are connected with the folding and faulting
+of the rocks of the earth&rsquo;s crust. They indicate a relief of
+the strain to which the rock-masses are subjected by mountain-making
+and other crustal movements, and they are consequently
+apt to occur along the steep face of a table-land or the margin
+of a continent with a great slope from land to sea. In many
+cases the immediate seat of the originating impulse is located
+beneath the sea, giving rise to submarine disturbances which
+have been called &ldquo;seaquakes.&rdquo; Much attention has been given
+to these suboceanic disturbances by Professor E. Rudolph.</p>
+
+<p>Professor J.H. Jeans has pointed out that the regions of the
+earth&rsquo;s crust most affected by earthquakes lie on a great circle
+corresponding with the equator of the slightly pear-shaped
+figure that he assigns to the earth. This would represent a belt
+of weakness, subject to crushing, from the tendency of the pear
+to pass into a spherical or spheroidal form under the action of
+internal stresses. According to the comte de Montessus de
+Ballore, the regions of maximum seismic instability appear
+to be arranged on two great circles, inclined to each other at
+about 67°. These are the Circumpacific and Mediterranean zones.</p>
+
+<p>Maps of the world, showing the origins of large earthquakes
+each year, accompany the Annual Reports of the Seismological
+Committee of the British Association, drawn up by Professor
+Milne. It is important to note that Professor Milne has shown
+a relationship between earthquake-frequency and the wandering
+of the earth&rsquo;s pole from its mean position. Earthquakes seem
+to have been most frequent when the displacement of the pole
+has been comparatively great, or when the change in the direction
+of movement has been marked. Valuable earthquake catalogues
+have been compiled at various times by Alexis Perrey, R. and
+J.W. Mallet, John Milne, T. Oldham, C.W.C. Fuchs, F. de
+Montessus de Ballore and others.</p>
+
+<p>Such earthquakes as are felt from time to time in Great Britain
+may generally be traced to the formation of faults, or rather
+to incidents in the growth of old faults. The East
+Anglian earthquake of the 22nd of April 1884&mdash;the
+<span class="sidenote">British earthquakes.</span>
+most disastrous that had occurred in the British Isles
+for centuries&mdash;was investigated by Prof. R. Meldola
+and W. White on behalf of the Essex Field Club. The shocks
+probably proceeded from two foci&mdash;one near the villages of
+Peldon and Abberton, the other near Wivenhoe and Rowhedge,
+in N.E. Essex. It is believed that the superficial disturbance
+resulted from rupture of rocks along a deep fault. An attempt
+has been made by H. Darwin, for the Seismological Committee
+of the British Association, to detect and measure any gradual
+movement of the strata along a fault, by observation at the
+Ridgeway fault, near Upway, in Dorsetshire. Dr C. Davison
+in studying the earthquakes which have originated in Britain
+since 1889 finds that several have been &ldquo;twins.&rdquo; A twin earthquake
+has two maxima of intensity proceeding from two foci,
+whereas a double earthquake has its successive impulses from
+what is practically a single focus. The Hereford earthquake
+of December 1896, which resulted in great structural damage,
+was a twin, having one epicentre near Hereford and the other
+near Ross. Davison refers it to a slip along a fault-plane between
+the anticlinal areas of Woolhope and May Hill; and according
+to the same authority the Inverness earthquake of the 18th of
+September 1901 was referable to movement along a fault
+between Loch Ness and Inverness. The South Wales earthquake
+of June 27, 1906, was probably due to movement connected
+with the Armorican system of folds, striking in an east and west
+direction.</p>
+
+<p>It may be noted that when a slip occurs along a fault, the
+displacement underground may be but slight and may die out
+before reaching the surface, so that no scarp is formed. In
+connexion, however, with a seismic disturbance of the first
+magnitude the superficial features may be markedly affected.
+Thus, the great Japan earthquake of October 1891&mdash;known
+often as the Mino-Owari earthquake&mdash;was connected with
+the formation or development of a fault which, according to
+Professor B. Koto, was traced on the surface for a distance of
+nearly 50 m. and presented in places a scarp with a vertical
+throw of as much as 20 ft., while probably the maximum displacement
+underground was very much greater.</p>
+
+<p>Although most earthquakes seem to be of tectonic type,
+there are some which are evidently connected, directly or
+indirectly, with volcanic activity (see <span class="sc"><a href="#artlinks">Volcano</a></span>). Such, it is
+commonly believed, were the earthquakes which disturbed
+the Isle of Ischia in 1881 and 1883, and were studied by Professor
+J. Johnston-Lavis and G. Mercalli. In addition to the tectonic
+and volcanic types, there are occasional earthquakes of minor
+importance which may be referred to the collapse of the roof of
+<span class="pagenum"><a name="page820" id="page820"></a>820</span>
+caverns, or other falls of rock in underground cavities at no
+great depth. According to Prof. T.J.J. See most earthquakes
+are due, directly or indirectly, to the explosive action of steam,
+formed chiefly by the leakage of sea-water through the ocean floor.</p>
+
+<p>Whatever the nature of the impulse which originates the
+earthquake, it gives rise to a series of waves which are propagated
+through the earth&rsquo;s substance and also superficially. In
+one kind, known as normal or condensational waves,
+<span class="sidenote">Earthquake waves.</span>
+or waves of elastic compression, the particles vibrate
+to and from the centre of disturbance, moving in the
+direction in which the wave travels, and therefore in a way
+analogous to the movement of air in a sound-wave. Associated
+with this type are other waves termed transverse waves, or
+waves of elastic distortion, in which the particles vibrate across
+or around the direction in which the wave is propagated.
+The normal waves result from a temporary change of volume
+in the medium; the transverse from a change of shape. The
+distance through which an earth-particle moves from its mean
+position of rest, whether radially or transversely, is called the
+amplitude of the wave; whilst the double amplitude, or total
+distance of movement, to and fro or up and down, like the
+distance from crest to trough of a water wave, may be regarded
+as the range of the wave. The period of a wave is the time
+required for the vibrating particle to complete an oscillation.
+As the rocks of the earth&rsquo;s crust are very heterogeneous, the
+earthquake-waves suffer refraction and reflection as they pass
+from one rock to another differing in density and elasticity.
+In this way the waves break up and become much modified in
+course of transmission, thus introducing great complexity into
+the phenomena. It is known that the normal waves travel
+more rapidly than the transverse.</p>
+
+<p>Measurements of the surface speed at which earthquake-waves
+travel require very accurate time-measurers, and these are
+not generally available in earthquake-shaken regions. Observations
+during the Charleston earthquake of 1886 were at that time
+of exceptional value, since they were made over a large area
+where standard time was kept. Lines drawn through places
+around the epicentre at which the shock arrives at the same
+moment are called coseismal lines. The motion of the wave is to
+be distinguished from the movement of the vibrating particles.
+The velocity of the earth-particle is its rate of movement, but
+this is constantly changing during the vibration, and the rate
+at which the velocity changes is technically called the acceleration
+of the particle.</p>
+
+<p>Unfelt movements of the ground are registered in the
+earthquake records, or seismograms, obtained by the delicate
+instruments used by modern seismologists. From the study of
+the records of a great earthquake from a distant source, sometimes
+termed a teleseismic disturbance, some interesting inferences
+have been drawn with respect to the constitution of
+the interior of the earth. The complete record shows two phases
+of &ldquo;preliminary tremors&rdquo; preceding the principal waves. It is
+believed that while the preliminary tremors pass through the
+body of the earth, the principal waves travel along or parallel to
+the surface. Probably the first phase represents condensational,
+and the second phase distortional, waves. Professor Milne concludes
+from the speed of the waves at different depths that
+materials having similar physical properties to those at the
+surface may extend to a depth of about 30 m., below which they
+pass into a fairly homogeneous nucleus. From the different rates
+of propagation of the precursors it has been inferred by R.D.
+Oldham that below the outer crust, which is probably not
+everywhere of the same thickness, the earth is of practically
+uniform character to a depth of about six-tenths of the radius,
+but the remaining four-tenths may represent a core differing
+physically and perhaps chemically from the outer part.
+Oldham also suggests, from his study of oceanic and continental
+wave-paths, that there is probably a difference in the constitution
+of the earth beneath oceans and beneath continents.</p>
+
+<p>The surface waves, which are waves of great length and long
+period and are propagated to great distances with practically a
+constant velocity, have been regarded as quasi-elastic gravitational
+waves. Further, in a great earthquake the surface of the ground
+is sometimes visibly agitated in the epifocal district by undulations
+which may be responsible for severe superficial damage.
+(See also for elastic waves <span class="sc"><a href="#artlinks">Elasticity</a></span>, § 89.)</p>
+
+<p>An old classification of earthquake-shocks, traces of which still
+linger in popular nomenclature, described them as &ldquo;undulatory,&rdquo;
+when the movement of the ground was mainly in a horizontal
+direction; &ldquo;subsultory,&rdquo; when the motion was vertical, like the
+effect of a normal wave at the epicentre; and &ldquo;vorticose,&rdquo;
+when the movement was rotatory, apparently due to successive
+impulses in varying directions.</p>
+
+<p>The sounds which are associated with seismic phenomena,
+often described as subterranean rumbling and roaring, are not
+without scientific interest, and have been carefully studied by
+Davison. &ldquo;Isacoustic lines&rdquo; are curves drawn through places
+where the sound is heard by the same percentage of observers.
+The sound is always low and often inaudible to many.</p>
+
+<p>The refined instruments which are now used by seismologists
+for determining the elements of earthquake motion and for
+recording earthquakes from distant origins are described in the
+article <span class="sc"><a href="#artlinks">Seismometer</a></span>. These instruments were developed as a
+consequence of the attention given in modern times to the study
+of earthquakes in the Far East.</p>
+<div class="author">(F. W. R.*)</div>
+
+<p class="pt1">Strange as it may appear, the advances that have been
+made in the study of earthquakes and the world-wide interest
+shown in their phenomena were initiated in work commenced
+in Japan. When the Japanese government,
+<span class="sidenote">Seismology in Japan.</span>
+desiring to adopt Western knowledge, invited to
+its shores bodies of men to act as its instructors, the
+attention of the newcomers was naturally attracted to the
+frequent shakings of the ground. Interest in these phenomena
+increased more rapidly than their frequency, and at length it was
+felt that something should be done for their systematic study.
+At midnight on the 22nd of February 1880 movements more
+violent than usual occurred; chimneys were shattered or rotated,
+tiles slid down from roofs, and in the morning it was seen that
+Yokohama had the appearance of a city that had suffered a
+bombardment. The excitement was intense, and before the ruins
+had been removed a meeting was convened and the Seismological
+Society of Japan established. The twenty volumes of original
+papers published by this body summarize to a large extent the
+results of the later study of seismology.<a name="fa1d" id="fa1d" href="#ft1d"><span class="sp">1</span></a></p>
+
+<p>The attention of the students of earthquakes in Japan was
+at first directed almost entirely to seismometry or earthquake
+measurement. Forms of apparatus which then existed, as for
+example the seismographs, seismometers and seismoscopes
+of Mallet, Palmieri and others, were subjected to trial; but
+inasmuch as they did little more than indicate that an earthquake
+had taken place&mdash;the more elaborate forms recording also the
+time of its occurrence&mdash;they were rapidly discarded, and instruments
+were constructed to <i>measure</i> earthquake motion. Slightly
+modified types of the new instruments devised in Japan were
+adopted throughout the Italian peninsula, and it is fair to say
+that the seismometry developed in Japan revolutionized the
+seismometry of the world. The records obtained from the new
+instruments increased our knowledge of the character of earthquake
+motion, and the engineer and the architect were placed
+in a position to construct so that the effects of known movements
+could be minimized. It was no doubt the marked success, both
+practical and scientific, attending these investigations that led
+the Japanese government to establish a chair of seismology at its
+university, to organize a system of nearly 1000 observing stations
+throughout the country, and in 1893 to appoint a committee of
+scientific and practical men to carry out investigations which
+might palliate the effects of seismic disturbances. In the first
+year this committee received a grant of £5000, and as liberal
+sums for the same purpose appear from time to time in the
+<span class="pagenum"><a name="page821" id="page821"></a>821</span>
+parliamentary estimates, it may be assumed that the work has
+been fraught with good results. In their publications we find not
+only records of experiences and experiments in Japan, but descriptions
+and comments upon earthquake effects in other countries.
+In two of the volumes there are long and extremely well illustrated
+accounts of the earthquake which on the 12th of June
+1897 devastated Assam, to which country two members of the
+above-mentioned committee were despatched to gather such
+information as might be of value to the architect and builder
+in earthquake-shaken districts.</p>
+
+<p>A great impetus to seismological investigation in Europe and
+America was no doubt given by the realization of the fact that
+a large earthquake originating in any one part of the
+world may be recorded in almost any other. Italy
+<span class="sidenote">Seismological research.</span>
+for many years past has had its observatories for
+recording earthquakes which can be felt, and which
+are of local origin, but at the present time at all its first-class
+stations we find instruments to record the unfelt movements
+due to earthquakes originating at great distances, and as much
+attention is now paid to the large earthquakes of the world as
+to the smaller ones originating within Italian territory.<a name="fa2d" id="fa2d" href="#ft2d"><span class="sp">2</span></a> The
+<i>Kaiserliche Akademie der Wissenschaften</i> of Vienna established
+earthquake observatories in Austria,<a name="fa3d" id="fa3d" href="#ft3d"><span class="sp">3</span></a> and the Central Observatorium
+of St Petersburg has carried out similar work in Russia.
+Germany attached a seismological observatory to its university
+at Strassburg, whilst provision has been made for a professorship
+of Earth Physics (<i>Geophysik</i>) at Göttingen.<a name="fa4d" id="fa4d" href="#ft4d"><span class="sp">4</span></a> In accordance with
+the recommendation of the British Association, seismographs
+of a similar character have been installed at stations all over
+the world.<a name="fa5d" id="fa5d" href="#ft5d"><span class="sp">5</span></a> The principal objects of this extended and still
+extending system of stations are to determine the velocity with
+which motion is propagated over the surface and through the
+interior of the earth, to locate the positions of sub-oceanic earthquake
+origins, and generally to extend our knowledge respecting
+the physical nature of the planet on which we live.</p>
+
+<p>We now know that earthquakes are many times more frequent
+than was previously supposed. In Japan, for example, between
+1885 and 1892 no fewer than 8331 were recorded&mdash;that
+is to say, on the average there were during that time
+<span class="sidenote">Frequency of earthquakes.</span>
+more than 1000 disturbances per year. Although
+many of these did not cause a sensible shaking over
+areas exceeding a few hundred square miles, many of them were
+sufficiently intense to propagate vibrations round and through
+the globe. If we pick out the well-marked earthquake districts
+of the world, and give to each of them a seismicity or earthquake
+frequency per unit area one-third of that in Japan, the conclusion
+arrived at is that considerable areas of our planet are on the
+average shaken every half-hour.</p>
+
+<p>The knowledge which we now possess respecting the localities
+where earthquakes are frequent and the forms of the foci from
+which they have spread, enables us to speak definitely
+respecting the originating causes of many of these
+<span class="sidenote">Volcanoes and earthquakes.</span>
+phenomena. It is found, for example, that although
+in many countries there may be displays of volcanic
+and seismic activity taking place almost side by side, it is only
+rarely that there is direct relationship between the two. Now
+and then, however, before a volcano breaks into eruption there
+may be a few ineffectual efforts to form a vent, each of which
+is accompanied by no more than a slight local shaking of the
+ground. This is true even for the largest and most violent
+eruptions, when mountains have with practically a single effort
+blown off their heads and shoulders. Thus the earthquake which
+accompanied the eruption of Bandaisan, in central Japan, in
+1888 was felt only over a radius of 25 m. The analyses of the
+seismic registers of Japan clearly indicate that comparatively
+few shakings originate near to the volcanoes of the country, the
+majority of them, like those of many other countries, coming
+from regions where volcanic rocks are absent. The greatest
+number spread inland from the Pacific seaboard, the movement
+becoming more and more feeble as it approaches the backbone
+of the country, which is drilled with numerous volcanic vents.
+What is true for Japan is generally true for the western coasts of
+North and South America.</p>
+
+<p>Speaking broadly, earthquakes are most frequent along the
+steeper flexures in the earth&rsquo;s surface, and in those regions where
+there is geological evidence to show that slow secular
+movements in the earth&rsquo;s crust are possibly yet in
+<span class="sidenote">Origin of earthquakes.</span>
+progress. With a unit distance of 2 degrees, or 120
+geographical m., we find that the slopes running
+eastwards from the highlands of Japan and westwards from the
+Andean ridges down into the Pacific vary from 1 in 20 to 1 in 30,
+and it is on the faces or near to the bottom of these slopes that
+seismic efforts are frequent. The slopes running from Australia,
+eastern America and western Europe into the neighbouring
+oceans vary between 1 in 70 and 1 in 250, and in these regions
+earthquakes are of rare occurrence. The seismic activity met
+with in the Himalayas and the Alps finds its best explanation
+in the fact that these mountains are geologically recent, and
+there are no reasons to doubt that the forces which brought
+their folds into existence are yet in action.</p>
+
+<p>This peculiar association of earthquakes with pronounced
+topographical configuration and certain geological conditions
+evidently indicates that the origin of many of them is connected
+with rock folding. Inasmuch as certain large earthquakes have
+been accompanied by rock fracture, as for example in 1891,
+when in central Japan a fault some 50 m. in length was created,
+whilst the origins of others have been distinctly traced to the
+line of an existing fault or its continuation, we may conclude
+that the majority of earthquakes are spasmodic accelerations in
+the secular movements which are creating (and in some instances
+possibly obliterating) the more prominent features of the earth&rsquo;s
+surface. These secular movements, which include upheavals,
+subsidences, horizontal displacements&mdash;all of which are explained
+on the assumption of a crust seeking support on a nucleus
+gradually contracting by loss of heat, are collectively referred
+to as bradyseismical (<span class="grk" title="bradys">&#946;&#961;&#945;&#948;&#973;&#962;</span>, slow) movements. To these may
+be added movements directly attributable to the influence of
+gravity. Sub-oceanic districts in a state of seismic strain may
+be so far loaded by the accumulation of sediments that gentle
+bending may be accompanied by sudden yieldings. This possibly
+accounts for the frequency of earthquakes off the mouth of
+the Tonegawa on the eastern side of Japan. The distortions so
+frequently observed in fossils and pebbles, the varying thickness
+of contorted strata, and the &ldquo;creep&rdquo; in coal-mines, together
+with other phenomena, indicate that rocks may flow. Observations
+of this nature lead to the supposition that high plateau-like
+regions may be gradually subsiding under the influence of their
+own weight, and that the process of settlement may from time
+to time be spasmodic in its character. Whether the earthquakes
+which originate round the submerged basal frontiers of the
+continents bounding the Pacific are ever attributable to such
+activities, it is impossible to say. All that we know with certainty
+is that they are sometimes accompanied by such a vast displacement
+of material that the ocean has been set into a state of oscillation
+for periods of 24 hours, that in some instances there have
+been marked changes in depth, and that enormous sub-oceanic
+landslips have occurred. These phenomena are, however, equally
+well explained on the assumption of sudden faulting accompanied
+by violent shaking, which would dislodge steeply inclined
+beds of material beneath the ocean as it does upon the land.</p>
+
+<p><span class="pagenum"><a name="page822" id="page822"></a>822</span></p>
+
+<p>Although the proximate cause of earthquake motion is traced
+to sudden yieldings in the crust of the earth brought about
+by some form of bradyseismical action, the existence
+of at least two distinct types of seismic motion
+<span class="sidenote">Two types of earthquake motion.</span>
+indicates that the mechanical conditions accompanying
+the fracturing of rocks are not always identical.
+90 or 95% of the earthquakes which can be recorded consist
+of elastic or quasi-elastic vibrations. The remainder,
+including the large earthquakes, not only exhibit the elastic
+movements, but are accompanied by surface undulations which
+are propagated most certainly for some hundreds of miles round
+their origin, and then as horizontal movements sweep over the
+whole surface of the globe. The former of these may accompany
+the formation of a new fault or the sudden renewal of movement
+along an old one; they are cracking or rending effects, without
+any great displacement. The latter are probably fracturings
+accompanied by vertical and horizontal displacements of masses
+of the earth&rsquo;s crust sufficiently great to set up the observed
+surface undulations. These shocks are so frequently followed
+a few minutes later by disturbances, which from their similarity
+to the movements which have preceded them may be called
+earthquake echoes, that we are led to the speculation that we are
+here dealing with the caving-in of ill-supported portions of the
+earth&rsquo;s crust, the waves from which are radiated to boundaries
+and then returned to their origin to coalesce and give rise to a
+second impulse not unlike the primary. Succeeding the first
+repetition of motion recorded by the seismograph there is often
+a rhythmical repetition of similar wave groups, suggesting the
+existence within our earth of phenomena akin to multiple echoes.</p>
+
+<p>The introduction of new methods into seismometry quickly
+revolutionized our ideas respecting the character of earthquake
+motion. Although an earthquake may be strongly
+felt within a distance of 50 m. from its origin, and
+<span class="sidenote">Character of earthquake motion.</span>
+although the movements in the upper storeys of
+buildings within the shaken area may be large, the
+actual range of the horizontal motion of the ground is usually
+less than <span class="spp">1</span>&frasl;<span class="suu">10</span> of an inch. With such earthquakes ordinary seismographs
+for recording vertical motion do not show any disturbance.
+When the movement reaches ½ in. it becomes dangerous, and
+a back-and-forth movement of an inch is usually accompanied
+by destructive effects. In this latter case the amplitude of the
+vertical record which indicates the existence of surface waves
+will vary between ½ and <span class="spp">1</span>&frasl;<span class="suu">100</span> of an inch. In the earthquake which
+devastated central Japan on the 26th of October 1891, nearly
+every building within the epifocal district fell, the ground was
+fissured, forests slipped down from mountain sides to dam up
+valleys, whilst the valleys themselves were permanently compressed.
+The horizontal movements seem to have reached
+9 in. or 1 ft., and the surface undulations were visible to the eye.</p>
+
+<p>The rapidity with which the movements are performed varies
+throughout a disturbance. A typical earthquake usually commences
+with minute elastic vibrations, the periods
+of which vary between <span class="spp">1</span>&frasl;<span class="suu">5</span> and <span class="spp">1</span>&frasl;<span class="suu">20</span> of a second. These
+<span class="sidenote">Period and duration.</span>
+are recorded by seismographs, and are noticed by
+certain of the lower animals like pheasants, which
+before the occurrence of movement perceptible to human beings
+scream as if alarmed. When an earthquake is preceded by a
+sound we have evidence of preliminary tremors even more
+rapid than those recorded by seismographs. Following these
+precursors there is a shock or shocks, the period of which will be
+1 or 2 seconds. From this climax the movements, although
+irregular in character, become slower and smaller until finally
+they are imperceptible. The duration of a small earthquake
+usually varies from a few seconds to a minute, but large earthquakes,
+which are accompanied by surface undulations, may be
+felt for 2 or 3 minutes, whilst an ordinary seismograph indicates
+a duration of from 6 to 12 minutes. A free horizontal pendulum
+tells us that with severe earthquakes the ground comes to rest
+by a series of more or less rhythmical surgings, continuing over
+1 or 2 hours. Although the maximum displacement has a
+definite direction, the successive vibrations are frequently
+performed in many different azimuths. The predominating
+direction at a given station in certain instances is apparently
+at right angles to the strike of the neighbouring strata, this
+being the direction of easiest yielding.</p>
+
+<p>Earthquake motion as recorded at stations several thousands
+of miles distant from its origin exhibits characteristics strikingly
+different from those just described. The precursors
+now show periods of from 1 to 5 seconds, whilst the
+<span class="sidenote">Velocity.</span>
+largest movements corresponding to the shocks may have
+periods of from 20 to 40 seconds. The interval of time by
+which the first tremors have outraced the maximum movement
+has also become greater. Within a few hundreds of miles from
+an origin this interval increases steadily, the velocity of propagation
+of the first movements being about 2 km. per second,
+whilst that of the latter may be taken at about 1.6 km. per
+second. Beyond this distance the velocity of transmission of
+the first movements rapidly increases, and for great distances,
+as for example from Japan to England, it is higher than we
+should expect for waves of compression passing through steel
+or glass. This observation precludes the idea that these preliminary
+tremors have travelled through the heterogeneous
+crust of the earth, and since the average velocity of their transmission
+increases with the length of the path along which they
+have travelled, and we but rarely obtain certain evidence that a
+seismograph has been disturbed by waves which have reached
+it by travelling in opposite directions round the world, we are
+led to the conclusion that earthquake precursors pass through
+our earth and not round its surface. The following table relating
+to earthquakes, which originated off the coast of Borneo on the
+20th and 27th of September 1897, is illustrative of the velocities
+here considered:&mdash;</p>
+
+<table class="ws" summary="Contents">
+<tr><td class="tccm allb">Localities.</td>
+  <td class="tccm allb">Distance<br />from<br />origin<br />in degrees.</td>
+  <td class="tccm allb">Velocity<br />in kms.<br />per sec. if<br />on chord.</td>
+  <td class="tccm tb bb">¼ <span style="font-size: 500%;">&radic;</span></td>
+  <td class="tclm tb bb rb">Average<br />depth of<br />chord in<br />kms.</td></tr>
+
+<tr><td class="tcl lb rb">Nicolaieff</td> <td class="tcc rb">81°</td> <td class="tcc rb">8.1</td> <td class="tcc rb" colspan="2">8.0</td></tr>
+<tr><td class="tcl lb rb">Potsdam</td> <td class="tcc rb">92°</td> <td class="tcc rb">8.4</td> <td class="tcc rb" colspan="2">9.1</td></tr>
+<tr><td class="tcl lb rb">Catania, Ischia, Rocca di Papa, Rome</td> <td class="tcc rb">96°</td> <td class="tcc rb">9.0</td> <td class="tcc rb" colspan="2">9.5</td></tr>
+<tr><td class="tcl lb rb bb">Isle of Wight</td> <td class="tcc rb bb">103°</td> <td class="tcc rb bb">9.8</td> <td class="tcc rb bb" colspan="2">10.2</td></tr>
+</table>
+
+<p>The chords referred to here are those joining the earthquake
+origins and distant observing stations, and it will be noted that
+one-quarter of the square root of the average depths at which
+these run closely corresponds to observed average velocities
+if wave paths followed chords. This increase of velocity with
+average depth shows that the paths followed through the earth
+must be curved with their convexity towards the centre of the
+earth. These observations do not directly tell us to what extent
+a true wave path is deflected from the direction of a chord,
+but they suggest as an extremely plausible assumption that
+the square of the speed is a linear function of the depth below
+the surface of the earth. With this assumption Dr C.G. Knott
+shows that the square of the speed (v²) can be expressed
+linearly in terms of the average depth of the chord d, thus:
+v² = 2.9 + .026 d, the units being miles and seconds. The formula
+applies with fair accuracy to moderate and high values of d, but
+it gives too high a value for short chords. It follows that the
+square of the speed increases 0.9% per mile of descent in the
+earth. The conclusion we arrive at is that the preliminary
+tremors which pass through the earth do so in the vicinity
+of their origin at the rate of almost 2.3 km. per second. This
+velocity increases as the wave path plunges downwards, attaining
+in the central regions a velocity of 16 to 17 kms., whilst the
+highest average velocity which is across a diameter lies between
+10 and 12 kms. per second.</p>
+
+<p>The large surface waves radiating from an origin to a distant
+place have velocities lying between 1.6 and 4 kms. per second,
+and it has been observed that when the higher velocity has been
+noted this refers to an observation at a station very remote
+from the origin. One explanation of this is the assumption that
+only very large waves indicating a large initial disturbance are
+capable of travelling to great distances, and as pointed out by
+<span class="pagenum"><a name="page823" id="page823"></a>823</span>
+R.D. Oldham, large waves under the influence of gravity will
+travel faster than small waves. These waves (which may be
+gravitational or distortional) are recorded as slow tiltings of the
+ground measured by angles of 0.5 to 10 or 15 seconds of arc, or
+as horizontal displacements of 0.5 or several millimetres. Their
+calculated lengths have reached 50 kms. (31 m.).</p>
+
+<p>In the section of this article relating to the cause of earthquakes
+a little has been said about their frequency or the number of
+times these phenomena are repeated during a given
+interval of time. It has been shown that all countries
+<span class="sidenote">Frequency.</span>
+are very often moved by earthquakes which have originated
+at great distances. Great Britain, for example, is crossed about
+100 times a year by earthquake waves having durations of from
+3 minutes to 3 hours, whilst the vibratory motions which originate
+in that country are not only small but of rare occurrence. In the
+earlier stages of the world&rsquo;s history, because the contraction of
+its nucleus was more rapid than it is at present, it is commonly
+inferred that phenomena accompanying bradyseismical activity
+must have been more pronounced and have shown themselves
+upon a grander scale than they do at the present time. Now,
+although the records of our rocks only carry us back over a certain
+portion of this history, they certainly represent an interval of
+time sufficiently long to furnish some evidence of such enfeeblement
+if it ever existed. So far from this being the case, however,
+we meet with distinct evidences in the later chapters of geological
+history of plutonic awakenings much more violent than those
+recorded at its commencement. During Palaeozoic times many
+mountain ranges were formed, and accompanying these orogenic
+processes there was marked volcanic activity. In the succeeding
+Secondary period plutonic forces were quiescent, but during
+the formation of the early Tertiaries, when some of the largest
+mountain ranges were created, they awoke with a vigour greater
+than had ever been previously exhibited. At this period it is not
+improbable that Scotland was as remarkable for its volcanoes
+and its earthquakes as Japan is at the present day. If the
+statement relating to the general decrease in bradyseismical
+changes referred merely to their frequency, and omitted reference
+to their magnitude, the views of the geologist and physicist
+might harmonize. One explanation for this divergence of
+opinion may rest on the fact that too little attention has been
+directed to all the conditions which accompany the adaptation
+of the earth&rsquo;s crust to its shrinking nucleus. As the latter grows
+smaller the puckerings and foldings of the former should grow
+larger. Each succeeding geological epoch should be characterized
+by mountain formations more stupendous than those which
+preceded them, whilst the fracturing, dislocation, caving-in of
+ill-supported regions, and creation of lines of freedom for the
+exhibition of volcanic activity which would accompany these
+changes, would grow in magnitude. The written records of
+many countries reflect but on a smaller scale the crystallized
+records in their hills. In 1844, at Comrie, in Perthshire, as many
+as twelve earthquakes were recorded in a single month, whilst
+now there are but one or two per year. Earthquake frequency
+varies with time. A district under the influence of hypogenic
+activities reaches a condition of seismic strain which usually
+is relieved rapidly at first, but subsequently more slowly.</p>
+
+<p>The small shocks which follow an initial large disturbance are
+known as after-shocks. The first shock which in 1891 devastated
+central Japan was accompanied by the formation of a large fault,
+and the 3364 small shocks which succeeded this during the
+following two years are regarded as due to intermittent settlements
+of disjointed material. The decreasing frequency with
+which after-shocks occur may be represented by a curve. Dr F.
+Omori points out that the continuation of such a curve gives the
+means of determining the length of time which will probably
+elapse before the region to which it refers will return to the same
+seismic quiescence that it had prior to the initial disturbance.</p>
+
+<p>The positive results that we have respecting the periodicity
+of earthquakes are but few. Generally earthquakes are somewhat
+more frequent during winter than during summer, and this
+applies to both the northern and southern hemispheres. The
+<span class="sidenote">Periodicity.</span>
+annual periodicity, which, however, does not show itself if only
+destructive earthquakes are considered, finds an explanation,
+according to Dr Knott, in the annual periodicity of long-continued
+stresses, as for example those due to the
+accumulation of snow and to barometric gradients.
+For certain earthquake regions there appears to be a
+distinct semi-annual period for which no satisfactory explanation
+has yet been adduced. Although the elaborate registers
+of Japan, which have enabled us to group earthquakes according
+to their respective origins and varying intensities, and to separate
+after-shocks from initial disturbances, have been subjected by
+Dr Knott to most careful analysis, with the object of discovering
+periodicities connected with the ebb and flow of the tides, the
+lunar day or lunar months, nothing of marked character has
+been found. Certainly there is slight evidence of a periodicity
+connected with the times of conjunction and opposition of the
+sun and moon, and a maximum frequency near the time of
+perigee, but the effect of lunar stresses is comparatively insignificant.
+Ordinary earthquakes, and especially after-shocks, show
+a diurnal period, but we cannot say that there are more earthquakes
+during the night than during the day.</p>
+
+<p>Many experiments and investigations have been made to
+determine a possible relationship between earthquakes and
+electrical phenomena, but beyond drawing attention
+to the fact that luminous appearances may accompany
+<span class="sidenote">Magnetic phenomena.</span>
+the friction of moving masses of rock, and that a
+temporary current may be established in a line by the
+disturbance of an earth-plate, these inquiries have yielded but
+little of importance. The inquiries respecting a possible relationship
+between adjustments so frequently taking place within
+and beneath that region called the crust of the earth and magnetic
+phenomena are, however, of a more promising nature.
+We have seen that at or near the origin of earthquakes which for
+several hours disturb continents, and occasionally cause oceans
+to oscillate for longer periods, we sometimes have direct evidence
+of the bodily displacement of many cubic miles of material.
+When this material is volcanic it is almost invariably magnetic,
+and we perceive in its sudden rearrangement causes which should
+produce magnetic effects within an epifocal district. In Japan,
+where attention is being directed to phenomena of this description,
+not only have such effects been observed, but unusual
+magnetic disturbances have been noted prior to the occurrence
+of large earthquakes. These may, of course, be regarded as mere
+coincidences, but when we consider volcanic and seismic activities
+as evidences of physical and chemical changes, together with
+mechanical displacements of a magnetic magma, it is reasonable
+to suppose that they should have at least a local influence
+upon magnetic needles. Another form of disturbance to which
+magnetic needles are subjected is that which accompanies the
+passage of large earth-waves beneath certain observatories
+situated at great distances from earthquake origins. At Utrecht,
+Potsdam and Wilhelmshaven the magnetographs are frequently
+disturbed by seismic waves, whilst at many other European
+observatories such effects are absent or only barely appreciable.
+To explain these marked differences in the behaviour of magnetic
+needles at different stations we are at present only in a position
+to formulate hypotheses. They may be due to the fact that
+different needles have different periodic times of oscillation;
+it is possible that at one observatory the mechanical movements
+of the ground are much greater than at others; we may speculate
+on the existence of materials beneath and around various observatories
+which are different in their magnetic characters; and,
+lastly, we may picture a crust of varying thickness, which from
+time to time is caused to rise and fall upon a magnetic magma,
+the places nearest to this being the most disturbed.</p>
+
+<p>A subject to which but little attention has been directed is
+the effect which displays of seismic and volcanic activities have
+had upon the human mind. The effects are distinctly
+dual and opposite in character. In countries like
+<span class="sidenote">Effects on the human mind.</span>
+England, where earthquakes are seldom experienced,
+the prevailing idea is that they are associated with all
+that is baneful. For certain earthquakes, which fortunately
+are less than 1% of those which are annually recorded, this is
+<span class="pagenum"><a name="page824" id="page824"></a>824</span>
+partially true. A disastrous shock may unnerve a whole community.
+Effects of this nature, however, differ in a marked
+manner with different nationalities. After the shock of 1891,
+when Japan lost 9960 of its inhabitants, amongst the wounded
+indications of mental excitement were shown in spinal and other
+trouble. Notwithstanding the lightheartedness of this particular
+nation, it is difficult to imagine that the long series of seismic
+effects chronicled in Japanese history, which culminated in
+1896 in the loss of 29,000 lives by sea-waves, has been without
+some effect upon its mental and moral character. Several
+earthquakes are annually commemorated by special services
+at temples. In bygone times governments have recognized
+earthquakes as visitations of an angry deity, whom they have
+endeavoured to appease by repealing stringent laws and taxes.
+In other countries the sermons which have been preached to
+show that the tremblings of the world were visitations consequent
+on impiety, and the prayers which have been formulated to
+ward off disasters in the future, far exceed in number the earthquakes
+which gave rise to them. In 1755 many of the English
+clergy held the view that Lisbon was destroyed because its
+inhabitants were Catholics, whilst the survivors from that
+disaster attributed their misfortune to the fact that they had
+tolerated a few Protestant heretics in their midst. To avoid
+a recurrence of disaster certain of these were baptized by force.
+In the myths relating to underground monsters and personages
+that are said to be the cause of earthquakes we see the direct
+effects which exhibitions of seismic and volcanic activity have
+produced upon the imagination. The beliefs, or more properly,
+perhaps, the poetical fancies, thus engendered have exhibited
+themselves in various forms. Beneath Japan there is said to be
+a catfish, which in other countries is replaced by a mole, a hog,
+an elephant or other living creature, which when it is restless
+shakes the globe. The Kamchadales picture a subterranean
+deity called Tuil, who in Scandinavian mythology is represented
+by the evil genius Loki. We have only to think of the reference
+in the Decalogue forbidding the making of graven images of that
+which is in the earth beneath, to see in early Biblical history
+evidence of a subterranean mythology; and it seems probable
+that the same causes which led to the creation of Pluto, Vulcan
+and Poseidon gave rise to practices condemned by Moses.</p>
+
+<p>Perhaps the greatest practical benefits derived from seismological
+investigations relate to important changes and new
+principles which have been introduced into the arts of
+the engineer and builder when constructing in earthquake
+<span class="sidenote">Building to withstand earthquakes.</span>
+countries. The new rules and formulae, rather
+than being theoretical deductions from hypotheses,
+are the outcome of observation and experiment. True
+measures of earthquake motion have been given to us by modern
+seismometers, with the result that seismic destructivity can be
+accurately expressed in mechanical units. From observation
+we now know the greatest acceleration and maximum velocity
+of an earth particle likely to be encountered; and these are
+measures of the destructivity. The engineer is therefore dealing
+with known forces, and he has to bear in mind that these are
+chiefly applied in a horizontal direction. A formula connecting
+the acceleration requisite to overturn bodies of different dimensions
+has been given. The acceleration which will fracture or
+shatter a column firmly fixed at its foundation to the moving
+earth may be expressed as follows:&mdash;</p>
+
+<table class="math0" summary="math">
+<tr><td rowspan="2">a =</td> <td>1</td>
+<td rowspan="2">&nbsp;</td> <td>gFAB</td>
+<td rowspan="2">,</td></tr>
+<tr><td class="denom">6</td> <td class="denom">fw</td></tr></table>
+
+<p class="noind">where</p>
+
+<div class="list f90">
+<p>a = the acceleration per sec. per sec.</p>
+<p>F = the force of cohesion, or force per unit surface, which when
+      gradually applied produces fracture.</p>
+<p>A = area of base fractured.</p>
+<p>B = thickness of the column.</p>
+<p>f = height of centre of gravity of column above the fractured base.</p>
+<p>w = the weight of the portion broken off.</p>
+</div>
+
+<p>With this formula and its derivatives we are enabled to state
+the height to which a wall, for example, may be built capable
+of resisting any assumed acceleration. Experience has shown
+that yielding first shows itself at the base of a pier, a wall or a
+building, and it is therefore clear that the lower portion of such
+structures should be of greater dimensions or stronger than that
+above. Piers having these increased dimensions below, and
+tapering upwards in a proper manner, so that every horizontal
+section is sufficiently strong to resist the effects of the inertia
+of its superstructure, are employed to carry railways in Japan.
+In that country cast-iron piers are things of the past, whilst
+piers of masonry, together with their foundations, no longer
+follow the rules of ordinary engineering practice.</p>
+
+<p>After flood, fire, earthquake, or when opportunity presents
+itself, changes are introduced in the construction of ordinary
+buildings. In a so-called earthquake-proof house, although
+externally it is similar to other dwellings, we find rafters running
+from the ridge pole to the floor sills, an exceedingly light roof,
+iron straps and sockets replacing mortices and tenons, and many
+other departures from ordinary rules. Masonry arches for
+bridges or arched openings in walls (unless protected by lintels),
+heavy gables, ornamental copings, cappings for chimneys,
+have by their repeated failure shown that they are undesirable
+features for construction in earthquake countries. As sites for
+buildings it is well to avoid soft ground, on which the movement
+is always greater than on hard ground. Excessive movement
+also takes place along the face of unsupported openings, and for
+this reason the edges of scarps, bluffs, cuttings and river-banks
+are localities to be avoided. In short, the rules and precautions
+which have to be recognized so as to avoid or mitigate the
+effects of earthquake movement are so numerous that students
+of engineering and architecture in Japan receive a special course
+of lectures on this subject. When it is remembered that a large
+earthquake may entail a loss of life greater than that which
+takes place in many wars, and that for the reconstruction of
+ordinary buildings, factories and public works an expenditure
+of several million pounds sterling is required, the importance
+of these studies cannot be overrated. Severe earthquakes are
+fortunately unknown in the British Isles, but we have simply
+to turn our eyes to earthquake-shaken colonies and lands in
+close commercial touch with Great Britain to realize the importance
+of mitigating such disasters as much as possible, and
+any endeavour to obviate the wholesale destruction of life
+should appeal to the civilized communities of the world.</p>
+
+<p>An unexpected application of seismometry has been to record
+the vibration of railway trains, bridges and steamships. An
+instrument of suitable construction will give records
+of the more or less violent jolting and vibratory
+<span class="sidenote">Applications of seismometry.</span>
+movements of a train, and so localize irregularities
+due to changes in the character of ballast and sleepers,
+to variation in gauge, &amp;c. An instrument placed on a locomotive
+throws considerable light upon the effects due to the methods of
+balancing the wheels, and by alterations in this respect a saving
+of fuel of from 1 to 5 &#8468; of coal per mile per locomotive has
+sometimes been effected.</p>
+
+<p>By mapping the centres from which earthquakes originate
+off the coast of Japan, we have not only determined districts
+where geological activity is pronounced, but have placed before
+the cable engineer well-defined localities which it is advisable
+to avoid; and in the records of unfelt earthquakes which
+originate far from land similar information is being collected
+for the deeper parts of the oceans. Occasionally these records
+have almost immediately made clear the cause of a cable failure.
+From lack of such information in 1888, when the cables connecting
+Australia with the outer world were simultaneously broken,
+the sudden isolation was regarded as a possible operation of
+war, and the colonists called out their naval and military reserves.
+Records of earthquakes originating at great distances have
+also frequently enabled us to anticipate, to correct, to extend, or
+to disprove telegraphic accounts of the disasters. Whatever
+information a seismogram may give is certain, whilst the information
+gathered from telegrams may in the process of transit
+become exaggerated or minimized. Otherwise unaccountable
+disturbances in records from magnetographs, barographs and
+other instruments employed in observatories are frequently
+<span class="pagenum"><a name="page825" id="page825"></a>825</span>
+explained by reference to the traces yielded by seismometers.
+Perhaps the greatest triumph in seismological investigation has
+been the determination of the varying rates at which motion is
+propagated through the world. These measurements have already
+thrown new light upon its effective rigidity, and if we assume
+that the density of the earth increases uniformly from its surface
+towards its centre, so that its mean density is 5.5, then, according
+to Knott, the coefficient of elasticity which governs the transmission
+of preliminary tremors of an earthquake increases at a
+rate of nearly 1.2% per mile of descent.</p>
+<div class="author">(J. Mi.)</div>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;J. Milne, <i>Seismology</i> (London, 1898), <i>Earthquakes</i>
+(London, 1898), Bakerian Lecture, &ldquo;Recent Advances in Seismology,&rdquo;
+<i>Proc. Roy. Soc.</i>, 1906, 77, p. 365; J.A. Ewing, <i>Memoir
+on Earthquake Measurement</i> (Tokyo, 1883); C.E. Dutton, <i>Earthquakes
+in the Light of the New Seismology</i> (London, 1904); &ldquo;The
+Charleston Earthquake of Aug. 31, 1886,&rdquo; Ninth Annual <i>Report</i>
+of the United States Geological Survey, 1889; W.H. Hobbs, <i>Earthquakes,
+an Introduction to Seismic Geology</i> (London, 1908), &ldquo;The
+San Francisco Earthquake and Fire, 1906,&rdquo; <i>Bull. U.S. Geol. Surv.</i>
+No. 324; &ldquo;The California Earthquake of Ap. 18, 1906,&rdquo; <i>Rep. State
+Earthq. Com.</i> (Washington, D.C., 1908); R.D. Oldham, &ldquo;Report on
+the Great Earthquake of 12 June 1897,&rdquo; <i>Mem. Geol. Surv. India</i>, xxix.
+1899, &ldquo;On the Propagation of Earthquake Motion to great Distances,&rdquo;
+<i>Phil. Trans.</i>, 1900, A, vol. 194, p. 135, &ldquo;The Constitution
+of the Interior of the Earth as revealed by Earthquakes,&rdquo; <i>Quar.
+Jour. Geol. Soc.</i>, 1906, 62, p. 456; 1907, 63, p. 344; C. Davison, <i>A
+Study of Recent Earthquakes</i> (London, 1905); <i>The Hereford Earthquake
+of December 17, 1896</i> (Birmingham, 1899), &ldquo;The Investigation
+of Earthquakes,&rdquo; <i>Beiträge z. Geophysik</i>, Bd. ix., 1908, p. 201,
+and papers on British earthquakes in <i>Quart. Jour. Geol. Soc.</i>;
+T.J.J. See, &ldquo;The Cause of Earthquakes, Mountain Formation and
+Kindred Phenomena connected with the Physics of the Earth,&rdquo;
+<i>Proc. Amer. Phil. Soc.</i>, 1906, 45, p. 273; F. Frech, &ldquo;Erdbeben und
+Gebirgsbau,&rdquo; <i>Petermann&rsquo;s Mitteilungen</i>, Bd. 53, 1907, p. 245 (with
+maps); C.G. Knott, <i>The Physics of Earthquake Phenomena</i> (Oxford,
+1908); Comte F. de Montessus de Ballore, <i>Les Tremblements de terre:
+géographie séismologique</i> (Paris, 1906), <i>La Science séismologique</i>
+(1907); <i>Transactions of the Seismological Society of Japan; Seismological
+Journal</i> (Yokohama); <i>Bollettino della Società Sismologica
+Italiana</i> (Rome); <i>Reports of the British Association</i>, containing the
+annual reports of the Committee for Seismological Investigations;
+papers in the <i>Beiträge zur Geophysik</i> and the <i>Ergänzungsbände</i>.</p>
+</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1d" id="ft1d" href="#fa1d"><span class="fn">1</span></a> The publications for 1880-1892 were termed the <i>Transactions
+of the Seismological Society of Japan</i>, and for 1893-1895 the <i>Seismological
+Journal of Japan</i>. The observations are now published by
+the Earthquake Investigation Committee of Japan, and edited by
+F. Omori, professor of seismology at the university of Tokyo.</p>
+
+<p><a name="ft2d" id="ft2d" href="#fa2d"><span class="fn">2</span></a> The chief Italian station is at Rocca di Papa near Rome. It is
+equipped with delicate instruments designed by its director, Giovanni
+Agamennone. The records since 1895 are published in the <i>Bollettino
+della Società Sismologica Italiana</i>, edited by Luigi Palazzo, director
+of the Central Office for Meteorology and Geodynamics at Rome.</p>
+
+<p><a name="ft3d" id="ft3d" href="#fa3d"><span class="fn">3</span></a> The chief Austrian publications are:&mdash;<i>Mittheilungen der Erdbebencommission
+der k. Akad. der Wissen. in Wien</i> (since 1897); <i>Die
+Erdbebenwarte</i> (1901-1907); and the &ldquo;Neueste Erdbebennachrichten,
+<i>Beilage der Monatsschrift Die Erdbebenwarte</i>.&rdquo;</p>
+
+<p><a name="ft4d" id="ft4d" href="#fa4d"><span class="fn">4</span></a> The &ldquo;International Seismological Association&rdquo; was founded at
+Strassburg in 1903, and publishes the <i>Beiträge zur Geophysik</i>, edited
+by George Gerland, director of the Strassburg station; the papers
+are printed in several languages.</p>
+
+<p><a name="ft5d" id="ft5d" href="#fa5d"><span class="fn">5</span></a> The records of the British Association stations are published
+(since 1896) in the <i>Reports</i>. Chile has a national earthquake service
+(founded after the Valparaiso earthquake of August 1906) directed
+by comte de Montessus de Ballore.</p>
+</div>
+
+
+<hr class="art" />
+
+<table class="flt" style="float: right; width: 220px;" summary="Illustration">
+<tr><td class="figright1"><img style="width:163px; height:148px" src="images/img825.jpg" alt="" /></td></tr>
+<tr><td class="caption80"> From Strasburger&rsquo;s <i>Lehrbuch der
+Botanik</i>, by permission of Gustav
+Fischer.</td></tr>
+<tr><td class="caption1"><i>Geaster Granulosus</i>, nat. size.</td></tr></table>
+
+<p><span class="bold">EARTH-STAR<a name="ar46" id="ar46"></a></span> (<i>Geaster</i>), in botany, a kind of puff-ball, with a
+distinct outer coat which, on separating from the inner, splits
+into several divisions, which become
+reflexed and spread like a
+star. The inner coat enveloping
+the spores is supported, like a ball,
+either with or without a stalk on
+the upper face of the star. The
+spores escape generally by means
+of a distinct aperture which appears
+in the top of the ball. There
+are several species in Britain found
+on the ground or on decaying leaves.
+They are rare or local, but more
+common in the south or south-east of England than in other
+parts of Britain.</p>
+
+
+<hr class="art" style="clear: both;" />
+<p><span class="bold">EARTHWORM,<a name="ar47" id="ar47"></a></span> the common name of a chaetopod worm
+found nearly all over the world. Linnaeus recognized only one
+species of earthworm and named it <i>Lumbricus terrestris</i>. There
+are now one thousand well-characterized species known from
+different parts of the world, and the number increases almost
+daily. The earthworms of England belong entirely to the three
+genera <i>Lumbricus</i>, <i>Allolobophora</i> and <i>Allurus</i>, which are further
+subdivided by some systematists; and these genera form the
+prevalent earthworm fauna of the Palaearctic region and are
+also very numerous in the Nearctic region. Elsewhere they do
+not appear to be indigenous, but are replaced by the numerous
+other genera of the families enumerated in the article Chaetopoda
+(<i>q.v.</i>). It is a remarkable fact that these genera, comprizing a
+separate family <i>Lumbricidae</i>, when introduced into tropical
+and other countries, thrive abundantly and oust the indigenous
+forms. In gatherings of earthworms from various extra-European
+countries it is always found that if the collections have been
+made in cultivated ground and near the coast the worms are of
+European species; farther inland the native forms are met with.
+Inasmuch as in every case the <i>Lumbricidae</i> from non-European
+countries are identical with European species, since it has been
+shown that these animals are very readily introduced accidentally
+with plants, &amp;c., and in view of the fact that they are impatient
+of sea water, it seems clear that the presence of these <i>Lumbricidae</i>
+in other continents is due to accidental transportation. Most
+earthworms live in the soil, which they devour as they burrow
+through it. A few, like their allies the river worms (Limicolae),
+habitually frequent streams, lakes, &amp;c. One genus, at any rate,
+viz. <i>Pontodrilus</i>, seeks an unusual environment, and is found
+in heaps of sea-weed cast up by the sea. The range of this genus
+is therefore naturally wider than that of other genera which are
+confined to land masses and cannot cross the sea by their own
+efforts. It might be inferred, therefore, and the inference is
+proved by facts, that truly oceanic islands have no indigenous
+fauna of earthworms, but are inhabited by forms which are
+identical with those of neighbouring continents, and doubtless,
+therefore, accidentally introduced.</p>
+
+<p>Like the leeches the earthworms produce cocoons which are
+a product of the glandular epithelium of the clitellum. In these
+cocoons are deposited the eggs together with a certain amount
+of albumen upon which the developing embryos feed. So far
+as is known, the production of cocoons is universal among
+earthworms and the remaining Oligochaeta of aquatic habit.
+The young leave the cocoon as fully formed earthworms in which,
+however, the genitalia are not fully developed. There is no
+free living larval stage. Out of a single cocoon emerge a varying
+number of young worms, the numbers being apparently characteristic
+of the species. The work of earthworms in aiding
+in the production of the subsoil and in levelling the surface was
+first studied by C. Darwin, and has since been investigated by
+others. This work is partly carried out beneath the surface
+and partly on the surface, upon which the worms wander at
+night and eject the swallowed and triturated earth; frequently
+castings of some height are formed of coiled ropes of agglutinated
+particles of mould. The indigenous species of Great Britain,
+about twenty in number, do not grow to a greater length than
+some 10 in.; but in several tropical countries there are species
+which grow to a length of from 3 to 6 ft. Thus we have in
+Natal the gigantic <i>Microchaeta rappi</i>, in Ceylon <i>Megascolex
+coeruleus</i>, in Australia <i>Megascolides australis</i>, and an equally
+large form in South America.</p>
+<div class="author">(F. E. B.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EARWIG,<a name="ar48" id="ar48"></a></span> an insect belonging to the <i>Forficulidae</i>, a family
+usually referred to the Orthoptera, but sometimes regarded
+as typifying a special order, to which the names Dermaptera,
+Dermatoptera and Euplexoptera have been given, in allusion
+to certain peculiarities in the structure of the wings in the species
+that possess them. The front wings are short and horny and
+when at rest meet without overlapping in the middle line, like
+the wing-cases of brachelytrous (cocktail) beetles. The hind
+wings, on the contrary, are for the most part membranous and,
+when extended, of large size; each consists of two portions, the
+distal of which, in virtue of the arrangement and jointing of its
+nervures, is capable of being both doubled up and folded fanwise
+beneath the proximal, which is partly horny when the wing is
+tucked away under the front wing-case of the same side. Apart
+from these characteristics, the most distinctive feature of
+earwigs is the presence at the end of the abdomen of a pair of
+pincers which are in reality modified appendages, known as
+cercopods, and represent the similar limbs of <i>Japyx</i> and the
+caudal feelers of <i>Campodea</i> and some other insects.</p>
+
+<p>The <i>Forficulidae</i> are almost cosmopolitan; but the various
+species and genera differ from each other both in structure and
+size to a comparatively slight extent. The length and armature
+of the pincers and the presence or absence of wings are perhaps
+the most important features used by systematists in distinguishing
+the various kinds. Of particular zoological interest in this
+connexion is a Ceylonese genus <i>Dyscritina</i>, in which the cercopods
+are long, many-jointed and filiform during the early stages of
+growth, and only assume at the last moult the forcipate structure
+characteristic of the family. The best known earwig is the
+common European species, <i>Forficula auricularia</i>. This insect
+is gregarious and nocturnal. It hides by day under stones or
+<span class="pagenum"><a name="page826" id="page826"></a>826</span>
+the loosened bark of trees or in any crevice or hole sheltered
+from the light. At night it crawls about in search of food, which
+consists to a small extent of dead animal or vegetable matter,
+but principally, as gardeners are aware, of the petals and other
+parts of flowers of growing shoots and soft ripe fruit. During
+the winter earwigs lie dormant; but in the early months of the
+year females with their eggs may be found in the soil, frequently
+in deserted earthworm burrows. Maternal instincts are well
+developed, both the eggs, which number about fifty, and the
+young being carefully brooded and watched over by the parent.
+Except for the absence of wings, the young are miniature models
+of the adult. As growth proceeds the integument is periodically
+cast; and at the final moult the perfect winged insect appears.
+Males and females are like each other in size, but may be distinguished
+by the difference in the number of visible abdominal
+segments, the male having nine and the female seven. In the
+male, moreover, the pincers are caliper-like and toothed at the
+base, whereas in the female they are untoothed and only lightly
+curved at the tip. These differences suggest that the pincers
+aid in the pairing of the sexes. However that may be, they
+are known to be used in the folding of the wings; and their
+importance as weapons of defence is attested by the precision
+and effect with which they are wielded against assailants
+like ants.</p>
+<div class="author">(R. I. P.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EASEMENT<a name="ar49" id="ar49"></a></span> (Fr. <i>aise</i>; O. Fr. <i>aisement</i>; Anglo-Lat. <i>aisiamentum</i>,
+a privilege or convenience), in English law, a species
+of &ldquo;servitude&rdquo; or limited right of use over land belonging to
+another. It is distinguished from <i>profits à prendre</i>&mdash;another
+species of servitude which involves a right to participate in the
+profits of the soil of another&mdash;since an easement confers merely
+a convenience (<i>aisiamentum</i>) to be exercised over the land of
+another (without any participation in the profits of it), <i>i.e.</i> a
+right to use the soil or produce of the soil in a way tending to the
+more convenient enjoyment of another piece of land. Thus
+a right of way is an easement, a right of common is a profit. An
+easement is distinguishable also from a licence, which, unless it
+is coupled with a grant, is personal to both grantor and grantee
+and is neither binding on the licensor, nor, in general, assignable
+by the licensee; while both the benefit and the burden of an
+easement are annexed to land (Gale on <i>Easements</i>, 8th ed. p. 2).
+With easements are sometimes classed certain closely allied
+&ldquo;natural rights,&rdquo; such as a landowner&rsquo;s right to lateral support
+for his soil in its natural state, and a riparian owner&rsquo;s right to the
+natural flow of a stream.</p>
+
+<p>The essential features of an easement, in the strict sense of
+the term, are therefore these: (i.) It is an incorporeal right;
+a right to the use and enjoyment of land&mdash;not to the land itself;
+(ii.) it is imposed upon corporeal property; (iii.) it is a right
+without profit; (iv.) it requires for its constitution two distinct
+tenements&mdash;the &ldquo;dominant tenement&rdquo; which enjoys the right,
+and the &ldquo;servient tenement&rdquo; which submits to it. This last
+characteristic excludes from the category of easements the
+so-called &ldquo;easements <i>in gross</i>,&rdquo; such as a right of way conferred
+by grant independently of the possession of any tenement by
+the grantee. The true easement is an &ldquo;appendant&rdquo; or &ldquo;appurtenant&rdquo;
+right, not a &ldquo;right in gross.&rdquo;</p>
+
+<p>Further classifications of easements must be noted. They
+are divided into (<i>a</i>) <i>affirmative</i> or <i>positive</i>, those which authorize
+the commission of an act by the dominant owner, <i>e.g.</i> rights of
+way, a right to draw water from a spring, rights of aqueduct,
+and <i>negative</i>, when the easement restricts the rights of the
+servient owner over his own property, <i>e.g.</i> prevents him from
+building on land so as to obstruct ancient lights (cf. also the
+right to the support of neighbouring soil); (<i>b</i>) <i>continuous</i>, of
+which the enjoyment may be continual without the interference
+of man, <i>e.g.</i> access to light, and <i>discontinuous</i>, where there must
+be a fresh act on each occasion of the exercise of the right, <i>e.g.</i>
+a right of way, or right to draw water; (<i>c</i>) <i>apparent</i>, where
+there are visible external signs of the exercise of the right, <i>e.g.</i> a
+right to dam up a watercourse, and <i>non-apparent</i>, where such
+signs are absent, <i>e.g.</i> a right to lateral support from land, a
+prohibition to build above a certain height.</p>
+
+<p><i>Acquisition of Easements.</i>&mdash;Easements may be acquired (<i>a</i>) by
+express grant, either by statute, or by deed <i>inter vivos</i>, or by
+will; (<i>b</i>) by an implied grant; (<i>c</i>) by express or implied reservation,
+<i>e.g.</i> by the owner of land in selling the fee (as to implied
+reservation, see Gale on <i>Easements</i>, 8th ed. pp. 137 et seq.);
+(<i>d</i>) by prescription, either at common law or under the Prescription
+Act 1832. An express grant, or express reservation, of an easement
+cannot be effected except by deed. An easement arises by
+implied grant where a man makes one part of his tenement dependent
+on another, or makes the parts mutually interdependent,
+and grants any such part with the dependence attaching to it to
+another person (Innes, <i>Law of Easements</i>, 7th ed. p. 10). For
+example, a man builds two houses, each of which by the plan of
+construction receives support from the other; this mutual
+right of support is a <i>quasi</i>-easement, of which on severance of
+the tenements the grantee of one will have the benefit; where
+the enjoyment of the severed tenement could not be had at all
+without such a right, it is said to be an &ldquo;easement of necessity.&rdquo;</p>
+
+<p>Easements are acquired by prescription at common law by
+proof of &ldquo;immemorial user&rdquo; by the dominant owner and those
+through whom he claims. At one time it was thought that
+such proof must date back to the first year (1189) of Richard I.
+(see preamble to Prescription Act 1832). The ground, however,
+on which prescription was admitted as a means of acquiring
+easements was the fiction of a &ldquo;lost grant.&rdquo; Long enjoyment
+of the right pointed to its having had a legal origin in a grant
+from the servient owner, and so any period of reasonably long
+use came to be accepted. A &ldquo;lost grant&rdquo; may be presumed to
+have been made (the question is one of fact) if 20 years&rsquo; uninterrupted
+enjoyment is shown. To avoid the difficulties of proof
+of prescriptive right at common law, the Prescription Act 1832
+established shorter periods of user. In the case of easements,
+other than light, the periods of prescription are 20 years for a
+claim that may be defeated, and 40 years for an indefeasible
+claim (s. 2). The right of access of light is dealt with under s. 3
+(see <span class="sc"><a href="#artlinks">Ancient Lights</a></span>). The enjoyment to become prescriptive
+must be open, <i>i.e.</i> of such a character that the owner of the
+tenement said to be servient has a reasonable opportunity of
+becoming aware of the adverse claim (<i>Union Lighterage Co.</i> v.
+<i>London Graving Dock Co.</i>, 1902, 2 Ch. 557); and it must be
+enjoyed as of right (<i>Gardner</i> v. <i>Hodgson&rsquo;s Kingston Brewery Co.</i>,
+1903, A.C. 229) as against the owner of the tenement affected
+(<i>Kilgour</i> v. <i>Gaddes</i>, 1904, 1 K.B. 457). The periods of prescription
+are to be reckoned backwards from the time when some
+suit or matter involving the claim of the dominant owner has
+arisen (s. 4). Nothing is to be deemed an interruption unless
+the act of interruption has been submitted to, or acquiesced in,
+for a year (s. 4).</p>
+
+<p>Easements may be extinguished (i.) by express release&mdash;here
+an instrument under seal is necessary; (ii.) by &ldquo;merger,&rdquo; <i>i.e.</i>
+where both tenements become the property of the same owner;
+(iii.) by abandonment through non-user. In the case of discontinuous
+easements, the shortest period of non-user may
+suffice if there is direct evidence of an intention to abandon.</p>
+
+<p>A word may be added here as to the right to air. It is an
+actionable nuisance to cause pollution of the air entering a
+dwelling-house. The owner of a dwelling-house may by prescription
+acquire a right to the passage of air through it by a
+defined channel; and the enjoyment without interruption of
+ventilation by means of air flowing in a definite channel, with the
+knowledge of the owner and occupier of the adjoining premises,
+creates a presumption of the grant of such an easement (see
+Gale on <i>Easements</i>, 8th ed. p. 338).</p>
+
+<p>In <i>Scots Law</i> the term &ldquo;easement&rdquo; is unknown. Both the
+name &ldquo;servitude&rdquo; and the main species of servitudes existing
+in Roman law (<i>q.v.</i>) have been adopted. The classification of
+servitudes into positive and negative, &amp;c., and the modes of
+their creation and extinction, are similar to those of English law.
+The statutory period of prescription is 40 years (Scots Acts 1617,
+c. 12), or 20 years in the case of enjoyment under any <i>ex facie</i>
+valid irredeemable title duly recorded in the appropriate register
+of sasines (Conveyancing [Scotland] Act 1874). There are
+<span class="pagenum"><a name="page827" id="page827"></a>827</span>
+certain servitudes special to Scots law, <i>e.g.</i> &ldquo;thirlage,&rdquo; by
+which lands are &ldquo;thirled&rdquo; or bound to a particular mill, and
+the possessors obliged to grind their grain there, for payment of
+certain <i>multures</i> (quantities of grain or meal, payable to the mill-owner)
+and <i>sequels</i> (small quantities given to the mill servants)
+as the customary price of grinding. Statutory provision has
+been made for the commutation of these duties (Thirlage Act
+1799), and they have now almost disappeared.</p>
+
+<p>The French Code Civil (Arts. 637 et seq.) and the other
+European codes (<i>e.g.</i> Belgium, arts. 637 et seq.; Holland, arts.
+721 et seq.; Italy, arts. 531 et seq.; Spain, arts. 530 et seq.;
+Germany, arts. 1018 et seq.) closely follow Roman law. French
+law is in force in Mauritius, and has been followed in Quebec
+(Civil Code, arts. 499 et seq.) and St Lucia (Civil Code, arts.
+449 et seq.). In India the law is regulated, on English lines,
+by the Easements Act 1882 (Act v. of 1882). The term &ldquo;easements,&rdquo;
+however, in India includes <i>profits à prendre</i>. In the
+South African colonies the law of easements is based on the
+Roman Dutch law (see Maasdorp, <i>Institutes of Cape Law</i>, 1904;
+Bk. ii. p. 166 et seq.). In most of the other colonies the law
+of easements is similar to English law. In some, however, it
+has been provided by statute that rights to the access and use of
+light or water cannot be acquired by prescription: <i>e.g.</i> Victoria
+(Water Act 1890, No. 1156, s. 3), Ontario (Real Property Limitation
+Act, Revised Stats. Ontario, 1897; c. 133, s. 36, light).</p>
+
+<p>In the <i>United States</i> the law of easements is founded upon,
+and substantially identical with, English law. The English
+doctrine, however, as to acquisition of right of light and air by
+prescription is not accepted in most of the States.</p>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;<i>English Law</i>: Gale, <i>Law of Easements</i> (8th ed.,
+London, 1908); Goddard, <i>Law of Easements</i> (6th ed., London,
+1904); Innes, <i>Digest of the Law of Easements</i> (7th ed., London, 1903).
+<i>Indian Law</i>: Peacock, <i>Easements in British India</i> (Calcutta, 1904);
+Hudson and Inman, <i>Law of Light and Air</i> (2nd ed., London, 1905).
+<i>Scots Law</i>: Erskine, <i>Principles of the Law of Scotland</i> (20th ed.,
+Edinburgh, 1903). <i>American Law</i>: Jones, <i>Law of Easements</i>
+(New York, 1898); Bouvier, <i>Law Dict.</i> (Boston and London, 1897);
+<i>Ruling Cases</i>, London and Boston, 1894-1901, tit. <i>Easement</i>
+(American Notes).</p>
+</div>
+<div class="author">(A. W. R.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EAST, ALFRED<a name="ar50" id="ar50"></a></span> (1849-&emsp;&emsp;), English painter and etcher, was
+born at Kettering on the 15th of December 1849. One of the
+most prominent among modern English landscape painters, he
+received his art education first at the Glasgow School of Art
+and then in Paris at the École des Beaux-Arts, and under
+Robert-Fleury and Bouguereau. His landscapes are remarkable
+for the lyrical use of colour and for the pleasing rhythm of line
+which is the result of careful selection and building up of the
+elements that constitute the scene. Based on keen observation of
+the colour of nature and on careful studies of the details, they are
+arranged with a rare and by no means obvious sense of balance
+and compositional beauty which summarily discards all disturbing
+accidents of nature. He also achieved distinction as
+an etcher, and published an instructive and useful volume
+on landscape painting (London, 1906). He began to exhibit at
+the Royal Academy in 1882, and was elected an associate. In
+1906 he became president of the Royal Society of British Artists.
+Many of his works are to be found in the English provincial
+galleries; Manchester owns &ldquo;The Silent Somme&rdquo; and &ldquo;Autumn&rdquo;;
+Liverpool, &ldquo;Gibraltar from Algeciras&rdquo;; Leeds, &ldquo;The Golden
+Valley&rdquo;; Birmingham, &ldquo;Hayle from Lelant&rdquo;; Preston, &ldquo;An Idyll
+of Spring&rdquo;; and Hull, &ldquo;Evening on the Cotswolds.&rdquo; His
+&ldquo;Passing Storm&rdquo; is at the Luxembourg; &ldquo;The Nene Valley&rdquo;
+at the Venice gallery; and &ldquo;A Haunt of Ancient Peace&rdquo; at
+the National gallery in Budapest. In 1903 he received the order
+of the Crown of Italy in connexion with his services to the
+Venice international exhibition; and he was made an honorary
+member of the Japanese Meiji Bijutsu Kai.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST ANGLIA,<a name="ar51" id="ar51"></a></span> one of the kingdoms into which Anglo-Saxon
+Britain was divided. Bede gives no information about its origin
+except that its earliest settlers were Angles. The kingdom of
+East Anglia comprised the two counties of Norfolk and Suffolk.
+With regard to the western boundary we have no accurate
+information, but it was probably formed by the fens of
+Cambridgeshire.</p>
+
+<p>This kingdom first appears in Bede&rsquo;s narrative early in the
+7th century, when its power was at its height. Towards the end
+of the reign of Æthelberht, who died about 616, Rædwald
+of East Anglia, who had apparently spent some time at the court
+of Kent, began to win for himself the chief position among the
+Anglo-Saxon kings of his day. His position was assured, at least
+temporarily, in 617, when he decided to espouse the cause of the
+Northumbrian prince Edwin, then a fugitive at his court, and
+defeated Æthelfrith of Northumbria on the banks of the Idle,
+a tributary of the Trent, in Mercian territory. Rædwald had
+been converted to Christianity in Kent, but after his return home
+he relapsed, according to Bede, owing to the influence of his wife,
+and there were to be seen in the same building a Christian and a
+pagan altar. Bede states that Rædwald was the son of Tytili,
+the son of Wuffa, from whom the East Anglian royal family
+derived their name Wuffingas. According to the <i>Historia
+Brittonum</i> Guffa (Wuffa) was the son of (Guecha) Wehha, who
+first ruled the East Angles in Britain. This would put the organization
+of the kingdom in the first or second quarter of the 6th
+century. Eorpwald, the son of Rædwald, was converted to
+Christianity by Edwin, but was soon afterwards slain by Ricberht
+(627 or 628), whereupon the kingdom again became pagan for
+three years, when Sigeberht, the brother of Eorpwald, became
+king and founded a see for Felix at Dunwich. Sigeberht also
+founded a school in East Anglia, and on the arrival of an Irish
+missionary named Fur&#353;eus he built him a monastery at <i>Cnobheresburg</i>,
+perhaps to be identified with Burgh Castle. Before
+644, however, Sigeberht resigned the crown in favour of his
+brother Ecgric and retired to a monastery. Shortly afterwards
+both brothers were slain by Penda of Mercia in his invasion of
+East Anglia, and Anna became king. This king was an enthusiastic
+Christian, and converted C&oelig;nwalh, king of Wessex,
+who had fled to his court. Two of his daughters, Sæthryth
+and Æthelberg, took the veil; while another, Sexburg, was
+married to Earconberht, king of Kent; and a fourth, Æthelthryth,
+after two marriages, with Tondberht of the South Gyrwe
+and Ecgfrith of Northumbria, became abbess of Ely. In 654
+Anna was slain by Penda of Mercia, and was succeeded by his
+brother Æthelhere, who was killed in 655 at the Winwaed,
+fighting for the Mercian king against Oswio of Northumbria.
+In 673 Archbishop Theodore divided the East Anglian diocese
+into two, Elmham being the seat of the northern, Dunwich
+that of the southern bishop. A long blank follows in the history
+of this kingdom, until in 792 we find Offa of Mercia slaying
+Æthelberht, king of East Anglia, who is said to have been his
+son-in-law. East Anglia was subject to the supremacy of the
+Mercian kings until 825, when its people slew Beornwulf of
+Mercia, and with their king acknowledged Ecgberht (Egbert)
+of Wessex as their lord. In 870 Edmund, king of East Anglia,
+was killed by the Danes under I&prime;varr and Ubbi, the sons of
+Ragnar Loðbrok.</p>
+
+<p>The following is a list of the kings of East Anglia of whom there
+is record:&mdash;Wehha; Wuffa; Rædwald, son of Tytili and grandson
+of Wuffa (reigning 617); Eorpwald, son of Rædwald (d. 627
+or 628); Sigeberht, brother of Eorpwald; Ecgric, brother of
+Sigeberht (both slain before 644); Anna, son of Ene and grandson
+of Tytili (d. 654); Æthelhere, brother of Anna (d. 655); Æthelwald,
+a third brother; Aldwulf (succ. 663, d. 713), son of
+Æthelric and grandson of Ene; Elfwald, son of Aldwulf (d. 749);
+Hun Beonna and Alberht; Æthelberht (792); Edmund (870).</p>
+
+<p>After the death of Ragnar Loðbrok&rsquo;s sons East Anglia was
+occupied by the Danish king Guthrum, who made a treaty
+with Alfred settling their respective boundaries, probably about
+880. Guthrum died in 890. A later king named Eohric took up
+the cause of Æthelwald, the son of Æthelred I., and was slain in
+the fight with the Kentish army at the Holm in 905. A war
+broke out with King Edward the Elder in 913; in 921 a king
+whose name is unknown was killed at the fall of Tempsford,
+and in the same year the Danes of East Anglia submitted to
+Edward the Elder. From this time, probably, East Anglia was
+governed by English earls, the most famous of whom were
+Æthelstan, surnamed Half-King (932-956) and his sons,
+<span class="pagenum"><a name="page828" id="page828"></a>828</span>
+Æthelwold (956-962), and Æthelwine, surnamed <i>Dei amicus</i>
+(962-992).</p>
+
+<div class="condensed">
+<p>See Bede, <i>Hist. Eccl.</i> (ed. C. Plummer, Oxford. 1896), ii. 5, 15,
+iii. 7, 8, 18-20, 22, iv. 3, 5, 23; <i>Saxon Chronicle</i> (ed. Earle and
+Plummer, Oxford, 1899), s. a. 823, 838, 866, 870, 880, 885, 890, 894,
+905, 921; <i>Historia Brittonum</i> (San-Marte, 1844), s. 59; H. Sweet,
+<i>Oldest English Texts</i>, p. 171 (London, 1885).</p>
+</div>
+<div class="author">(F. G. M. B.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EASTBOURNE<a name="ar52" id="ar52"></a></span>, a municipal borough (1883) in the Eastbourne
+parliamentary division of Sussex, England, 61 m. S.S.E. of
+London by the London, Brighton &amp; South Coast railway. Pop.
+(1891) 34,969; (1901) 43,344; (local census, 1909) 49,286. It
+is situated 3 m. N.E. of Beachy Head, the loftiest headland on the
+English Channel coast. It once consisted of three parts&mdash;the
+village of East Bourne, a mile inland; South Bourne, lying back
+from the shore; and Seahouses, facing the beach. The church
+of St Mary, the ancient parish church of East Bourne, is a
+fine transitional Norman building; and there are numerous
+modern churches and chapels. The principal buildings and
+institutions are the town hall and municipal buildings, the
+Princess Alice Memorial and other hospitals, a free library and,
+among many high-class schools, Eastbourne College for boys,
+founded in 1867. There is a fine pier with pavilion, and a marine
+parade nearly 3 m. in extent, arranged in terraced promenades.
+Devonshire Park of 13 acres is pleasantly laid out, and contains
+a pavilion and a theatre. The duke of Devonshire is the principal
+landowner. Golf links are laid out on the neighbouring downs.
+A Roman villa was formerly seen close to the shore, but it is
+not now visible. The corporation consists of a mayor, 8 aldermen
+and 24 councillors. In 1910 the corporation promoted a bill in
+parliament to add the Hampden Park district in the parish of
+Willingdon to the borough and to make Eastbourne, with this
+extension, a county borough.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST CHICAGO<a name="ar53" id="ar53"></a></span>, a city of Lake county, Indiana, U.S.A., on
+Lake Michigan, about 19 m. S.E. of the business centre of Chicago.
+Pop. (1890) 1255; (1900) 3411 (1331 foreign-born); (1910) 19,098.
+It is served by several railways, including the Pennsylvania, the
+Wabash, the Chicago Terminal Transfer (whose shops are here),
+the Lake Shore &amp; Michigan Southern, the Chicago, Indiana &amp;
+Southern, and the Indiana Harbor railways. East Chicago
+covers an area whose greatest dimensions are 4 by 3½ m. That
+part of the city along the lake, known as Indiana Harbor, dates
+from 1901 and has grown very rapidly because of its position at
+the southernmost part of the Calumet District, and because of the
+meeting here of railway and lake commerce. A good harbour
+has been constructed, a new ship canal connecting the harbour
+with the Calumet river. East Chicago is industrially virtually
+a part of &ldquo;Greater&rdquo; Chicago; among its manufactures are iron
+and steel, cement, lumber, boilers, hay presses, chains, chemicals
+and foundry products. East Chicago was chartered as a city in
+1893.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTER<a name="ar54" id="ar54"></a></span>, the annual festival observed throughout Christendom
+in commemoration of the resurrection of Jesus Christ.
+The name Easter (Ger. <i>Ostern</i>), like the names of the days
+of the week, is a survival from the old Teutonic mythology.
+According to Bede (<i>De Temp. Rat.</i> c. xv.) it is derived from
+<i>Eostre</i>, or <i>Ostâra</i>, the Anglo-Saxon goddess of spring, to whom
+the month answering to our April, and called <i>Eostur-monath</i>,
+was dedicated. This month, Bede says, was the same as the
+<i>mensis paschalis</i>, &ldquo;when the old festival was observed with the
+gladness of a new solemnity.&rdquo;</p>
+
+<p>The name of the festival in other languages (as Fr. <i>pâques</i>;
+Ital. <i>pasqua</i>; Span. <i>pascua</i>; Dan. <i>paaske</i>; Dutch <i>paasch</i>; Welsh
+<i>pasg</i>) is derived from the Lat. <i>pascha</i> and the Gr. <span class="grk" title="pascha">&#960;&#940;&#963;&#967;&#945;</span>.
+These in turn come from the Chaldee or Aramaean form <span title="pascha">&#1508;&#1505;&#1492;&#1488;</span>
+<i>pascha&rsquo;</i>, of the Hebrew name of the Passover festival <span title="pesach">&#1508;&#1505;&#1495;</span>
+<i>pesach</i>, from <span title="pasach">&#1508;&#1505;&#1495;</span> &ldquo;he passed over,&rdquo; in memory of the great
+deliverance, when the destroying angel &ldquo;passed over the houses,
+of the children of Israel in Egypt when he smote the Egyptians&rdquo;
+(Exod. xii. 27).</p>
+
+<p>An erroneous derivation of the word <i>pascha</i> from the Greek
+<span class="grk" title="paschein">&#960;&#940;&#963;&#967;&#949;&#953;&#957;</span>, &ldquo;to suffer,&rdquo; thus connected with the sufferings or
+passion of the Lord, is given by some of the Fathers of the Church,
+as Irenaeus, Tertullian and others, who were ignorant of Hebrew.
+St Augustine (<i>In Joann. Tract.</i> 55) notices this false etymology,
+shows how similarity of sound had led to it, and gives the
+correct derivation.</p>
+
+<p>There is no indication of the observance of the Easter festival
+in the New Testament, or in the writings of the apostolic Fathers.
+The sanctity of special times was an idea absent from the minds
+of the first Christians. &ldquo;The whole of time is a festival unto
+Christians because of the excellency of the good things which
+have been given&rdquo; is the comment of St Chrysostom on 1 Cor. v. 7,
+which has been erroneously supposed to refer to an apostolic
+observance of Easter. The ecclesiastical historian Socrates
+(<i>Hist. Eccl.</i> v. 22) states, with perfect truth, that neither the
+Lord nor his apostles enjoined the keeping of this or any other
+festival. He says: &ldquo;The apostles had no thought of appointing
+festival days, but of promoting a life of blamelessness and
+piety&rdquo;; and he attributes the observance of Easter by the
+church to the perpetuation of an old usage, &ldquo;just as many other
+customs have been established.&rdquo;</p>
+
+<p>This is doubtless the true statement of the case. The first
+Christians continued to observe the Jewish festivals, though in a
+new spirit, as commemorations of events which those festivals
+had foreshadowed. Thus the Passover, with a new conception
+added to it of Christ as the true Paschal Lamb and the first
+fruits from the dead, continued to be observed, and became the
+Christian Easter.</p>
+
+<p>Although the observance of Easter was at a very early period
+the practice of the Christian church, a serious difference as to
+the day for its observance soon arose between the Christians
+of Jewish and those of Gentile descent, which led to a long and
+bitter controversy. The point at issue was when the Paschal
+fast was to be reckoned as ending. With the Jewish Christians,
+whose leading thought was the death of Christ as the Paschal
+Lamb, the fast ended at the same time as that of the Jews, on the
+fourteenth day of the moon at evening, and the Easter festival
+immediately followed, without regard to the day of the week.
+The Gentile Christians, on the other hand, unfettered by Jewish
+traditions, identified the first day of the week with the Resurrection,
+and kept the preceding Friday as the commemoration of the
+crucifixion, irrespective of the day of the month. With the one
+the observance of the day of the month, with the other the
+observance of the day of the week, was the guiding principle.</p>
+
+<p>Generally speaking, the Western churches kept Easter on the
+first day of the week, while the Eastern churches followed the
+Jewish rule, and kept Easter on the fourteenth day. St Polycarp,
+the disciple of St John the Evangelist and bishop of Smyrna,
+visited Rome in 159 to confer with Anicetus, the bishop of that
+see, on the subject; and urged the tradition, which he had
+received from the apostle, of observing the fourteenth day.
+Anicetus, however, declined to admit the Jewish custom in the
+churches under his jurisdiction, but readily communicated with
+Polycarp and those who followed it. About forty years later
+(197) the question was discussed in a very different spirit between
+Victor, bishop of Rome, and Polycrates, metropolitan of proconsular
+Asia. That province was the only portion of Christendom
+which still adhered to the Jewish usage, and Victor demanded
+that all should adopt the usage prevailing at Rome. This
+Polycrates firmly refused to agree to, and urged many weighty
+reasons to the contrary, whereupon Victor proceeded to excommunicate
+Polycrates and the Christians who continued the
+Eastern usage. He was, however, restrained from actually
+proceeding to enforce the decree of excommunication, owing to
+the remonstrance of Irenaeus and the bishops of Gaul. Peace was
+thus maintained, and the Asiatic churches retained their usage
+unmolested (Euseb. <i>H.E.</i> v. 23-25). We find the Jewish usage
+from time to time reasserting itself after this, but it never
+prevailed to any large extent.</p>
+
+<p>A final settlement of the dispute was one among the other
+reasons which led Constantine to summon the council of Nicaea
+in 325. At that time the Syrians and Antiochenes were the
+solitary champions of the observance of the fourteenth day.
+The decision of the council was unanimous that Easter was to be
+kept on Sunday, and on the same Sunday throughout the world,
+<span class="pagenum"><a name="page829" id="page829"></a>829</span>
+and &ldquo;that none should hereafter follow the blindness of the
+Jews&rdquo; (Socrates, <i>H.E.</i> i. 9). The correct date of the Easter
+festival was to be calculated at Alexandria, the home of astronomical
+science, and the bishop of that see was to announce it
+yearly to the churches under his jurisdiction, and also to the
+occupant of the Roman see, by whom it was to be communicated
+to the Western churches. The few who afterwards separated
+themselves from the unity of the church, and continued to keep
+the fourteenth day, were named <i>Quartodecimani</i>, and the dispute
+itself is known as the <i>Quarto-deciman</i> controversy. Although
+measures had thus been taken to secure uniformity of observance,
+and to put an end to a controversy which had endangered
+Christian unity, a new difficulty had to be encountered owing
+to the absence of any authoritative rule by which the paschal
+moon was to be ascertained. The subject is a very difficult and
+complex one (see also <span class="sc"><a href="#artlinks">Calendar</a></span>). Briefly, it may be explained
+here that Easter day is the first Sunday after the full moon
+following the vernal equinox. This, of course, varies in different
+longitudes, while a further difficulty occurred in the attempt to
+fix the correct time of Easter by means of cycles of years, when
+the changes of the sun and moon more or less exactly repeat
+themselves. At first an eight years&rsquo; cycle was adopted, but it
+was found to be faulty, then the Jewish cycle of 84 years was
+used, and remained in force at Rome till the year 457, when a
+more accurate calculation of a cycle of 532 years, invented by
+Victorius of Acquitaine, took its place. Ultimately a cycle of
+19 years was accepted, and it is the use of this cycle which makes
+the Golden Number and Sunday Letter, explained in the preface
+to the Book of Common Prayer, necessary. Owing to this lack
+of decision as to the accurate finding of Easter, St Augustine
+tells us (<i>Epist.</i> 23) that in the year 387 the churches of Gaul kept
+Easter on the 21st of March, those of Italy on the 18th of April,
+and those of Egypt on the 25th of April; and it appears from
+a letter of Leo the Great (<i>Epist.</i> 64, <i>ad Marcian.</i>) that in 455 there
+was a difference of eight days between the Roman and the
+Alexandrine Easter. Gregory of Tours relates that in 577 &ldquo;there
+was a doubt about Easter. In Gaul we with many other cities
+kept Easter on the fourteenth calends of May, others, as the
+Spaniards, on the twelfth calends of April.&rdquo;</p>
+
+<p>The ancient British and Celtic churches followed the cycle of
+84 years which they had originally received from Rome, and
+their stubborn refusal to abandon it caused much bitter controversy
+in the 8th century between their representatives and
+St Augustine of Canterbury and the Latin missionaries. These
+latter unfairly attempted to fix the stigma of the Quartodeciman
+observance on the British and Celtic churches, and they are even
+now sometimes ignorantly spoken of as having followed the
+Asiatic practice as to Easter. This, however, is quite erroneous.
+The British and Celtic churches always kept Easter according
+to the Nicene decree on a Sunday. The difference between
+them and the Roman Church, at this period, was that they still
+followed the 84 years&rsquo; cycle in computing Easter, which had
+been abandoned at Rome for the more accurate cycle of 532 years.
+This difference of calculation led to Easter being observed on
+different Sundays, in certain years, in England, by the adherents
+of the two churches. Thus Bede records that in a certain year
+(which must have been 645, 647, 648 or 651) Queen Eanfleda,
+who had received her instruction from a Kentish priest of the
+Roman obedience, was fasting and keeping Palm Sunday, while
+her husband, Oswy, king of Northumbria, following the rule of
+the British church, was celebrating the Easter festival. This
+diversity of usage was ended, so far as the kingdom of Northumbria
+was concerned, by the council of Streaneshalch, or Whitby,
+in 654. To Archbishop Theodore is usually ascribed the credit
+of ending the difference in the rest of England in 669.</p>
+
+<p>The Gregorian correction of the calendar in 1582 has once more
+led to different days being observed. So far as Western Christendom
+is concerned the corrected calendar is now universally
+accepted, and Easter is kept on the same day, but it was not until
+1752 that the Gregorian reformation of the calendar was adopted
+in Great Britain and Ireland. Jealousy of everything emanating
+from Rome still keeps the Eastern churches from correcting the
+calendar according to the Gregorian reformation, and thus their
+Easter usually falls before, or after, that of the Western churches,
+and only very rarely, as was the case in 1865, do the two coincide.</p>
+
+<p>Easter, as commemorating the central fact of the Christian
+religion, has always been regarded as the chief festival of the
+Christian year, and according to a regulation of Constantine it
+was to be the first day of the year. This reckoning of the year
+as beginning at Easter lingered in France till 1565, when, by
+an ordinance of Charles IX., the 1st of January finally took
+its place.</p>
+
+<p>Four different periods may be mentioned as connected with
+the observance of Easter, viz. (1) the preparatory fast of the
+forty days of Lent; (2) the fifteen days, beginning with the
+Sunday before and ending with the Sunday after Easter, during
+which the ceremonies of Holy Week and the services of the
+Octave of Easter were observed; this period, called by the
+French the <i>Quinzaine de Pâques</i>, was specially observed in that
+country; (3) the Octave of Easter, during which the newly-baptized
+wore their white garments, which they laid aside on
+the Sunday after Easter, known as <i>Dominica in albis depositis</i>
+from this custom; another name for this Sunday was <i>Pascha
+clausum</i>, or the close of Easter, and from a clipping of the word
+&ldquo;close&rdquo; the English name of &ldquo;Low&rdquo; Sunday is believed to be
+derived; (4) Eastertide proper, or the paschal season beginning
+at Easter and lasting till Whit Sunday, during the whole of which
+time the festival character of the Easter season was maintained
+in the services of the church.</p>
+
+<p>Many ecclesiastical ceremonies, growing up from early times,
+clustered round the celebration of the Easter festival. One of
+the most notable of these was the use of the paschal candle.
+This was a candle of very large dimensions, set in a candlestick
+big enough to hold it, which was usually placed on the north
+side, just below the first ascent to the high altar. It was kept
+alight during each service till Whitsuntide. The Paschal, as it
+was called at Durham cathedral, was one of the chief sights of
+that church before the Reformation. It was an elaborate construction
+of polished brass, and, contrary to the usual custom,
+seems to have been placed in the centre of the altar-step, long
+branches stretching out towards the four cardinal points, bearing
+smaller candles. The central stem of the candlestick was about
+38 ft. high, and bore the paschal candle proper, and together
+they reached a combined height of about 70 ft., the candle being
+lighted from an opening above. Other paschal candles seem to
+have been of scarcely less size. At Lincoln, c. 1300, the candle
+was to weigh three stones of wax; at Salisbury in 1517 it was
+to be 36 ft. long; and at Westminster in 1558 it weighed no less
+than 3 cwt. of wax. After Whitsuntide what remained was made
+into smaller candles for the funerals of the poor. In the ancient
+churches at Rome the paschal candlesticks were fixtures, but
+elsewhere they were usually movable, and were brought into the
+church and set up on the Thursday before Easter. At Winchester
+the paschal candlestick was of silver, and was the gift of Canute.
+Others of more or less importance are recorded as having been
+at Canterbury, Bury St Edmunds, Hereford and York. The
+burning of the paschal candle still forms part of the Easter ceremonial
+of the Roman Catholic Church (see <span class="sc"><a href="#artlinks">Lights, Ceremonial</a></span>).</p>
+
+<p>The liturgical colour for Easter was everywhere white, as the
+sign of joy, light and purity, and the churches and altars were
+adorned with the best ornaments that each possessed. Flowers
+and shrubs no doubt in early times were also used for this
+purpose, but what evidence there is goes against the medieval
+use of such decorations, which are so popular at the present day.</p>
+
+<p>It is not the purpose of this article to enter on the wide subject
+of the popular observances, such as the giving and sending of
+Pasch or Easter eggs as presents. For such the reader may consult
+Brand&rsquo;s <i>Popular Antiquities</i>, Hone&rsquo;s <i>Every-Day Book</i>, and
+Chambers&rsquo;s <i>Book of Days</i>.</p>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;Bingham, <i>Antiquities of the Christian Church</i>;
+Bede, <i>Ecclesiastical History of England</i>; Procter and Frere, <i>A New
+History of the Book of Common Prayer</i> (London, 1901); Surtees
+Society, <i>Rites of Durham</i>, ed. J.T. Fowler (1903); De Morgan,
+<i>Companion to the Almanac</i> (1845); De Moleon, <i>Voyages liturgiques</i>
+(Paris, 1718).</p>
+</div>
+<div class="author">(T. M. F.)</div>
+
+<p><span class="pagenum"><a name="page830" id="page830"></a>830</span></p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTER ISLAND<a name="ar55" id="ar55"></a></span> (Rapanui, <i>i.e.</i> Great Rapa), an island in
+the eastern part of the South Pacific ocean, belonging to Chile
+(since 1888), in 27° 8&prime; S. and 109° 28&prime; W., 1400 m. E. of Pitcairn,
+and 2000 m. from the South American coast. It is roughly
+triangular in shape, with its hypotenuse 12 m. long running
+north-east and south-west, and its three angles marked by
+three volcanic peaks, of which the north-eastern reaches 1768 ft.
+of altitude. The area of the island is 45 sq. m. The coast has
+no good natural harbour, and landing is difficult. There is no lack
+of fertile soil, and the climate is moist enough to make up for the
+absence of running water. Formerly the island appears to have
+been wooded, but it now presents only a few bushes (<i>Edwardsia</i>,
+<i>Broussonetia</i>, &amp;c.), ferns, grasses, sedges, &amp;c. The natives grow
+bananas in the shelter of artificial pits, also sugar-canes and
+sweet potatoes, and keep a few goats and a large stock of domestic
+fowls, and a Tahitian commercial house breeds cattle and sheep
+on the island.</p>
+
+<p>It is doubtful whether Rapanui was discovered by Davis in
+1686, though it is sometimes marked Davis Island on maps.
+Admiral Roggeveen reached it on Easter day 1722; in 1774
+Captain Cook discovered it anew and called it Teapi or Waihu.
+It was subsequently visited by La Pérouse (1776), Kotzebue
+(1816), &amp;c. At the time of Roggeveen&rsquo;s discovery the island
+probably contained from 2000 to 3000 inhabitants of Polynesian
+race, who, according to their own tradition, came from Rapa Iti
+(Little Rapa) or Oparo, one of the Tubuai or Austral group.
+In 1863 a large proportion of the inhabitants were kidnapped
+by the Peruvians and transported to work at the guano diggings
+on the Chincha Islands. The next year a Jesuit mission from
+Tahiti reached the island and succeeded in the task of civilization.
+The natives, who number scarcely one hundred, are all Christians.</p>
+
+<p>Easter Island is famous for its wonderful archaeological
+remains. Here are found immense platforms built of large cut
+stones fitted together without cement. They are generally built
+upon headlands, and on the slope towards the sea. The walls
+on the seaside are, in some of the platforms, nearly 30 ft. high
+and from 200 to 300 ft. long, by about 30 ft. wide. Some of the
+squared stones are as much as 6 ft. long. On the land side of the
+platforms there is a broad terrace with large stone pedestals upon
+which once stood colossal stone images carved somewhat into
+the shape of the human trunk. On some of the platforms there
+are upwards of a dozen images, now thrown from their pedestals
+and lying in all directions. Their usual height is from 14 to 16 ft.,
+but the largest are 37 ft., while some are only about 4 ft. They
+are formed from a grey trachytic lava found at the east end
+of the island. The top of the heads of the images is cut flat to
+receive round crowns made of a reddish vesicular tuff found at
+a crater about 8 m. distant from the quarry where the images
+were cut. A number of these crowns still lie at the crater
+apparently ready for removal, some of the largest being over 10 ft.
+in diameter. In the atlas illustrating the voyage of La Pérouse
+a plan of the island is given, with the position of several of the
+platforms. Two of the images are also represented in a plate.
+One statue, 8 ft. in height and weighing 4 tons, was brought to
+England, and is now in the British Museum. In one part of the
+island are the remains of stone houses nearly 100 ft. long by
+about 20 ft. wide. These are built in courses of large flat stones
+fitted together without cement, the walls being about 5 ft.
+thick and over 5 ft. high. They are lined on the inside with
+upright slabs, on which are painted geometrical figures and
+representations of animals. The roofs are formed by placing
+slabs so that each course overlaps the lower one until the opening
+becomes about 5 ft. wide, when it is covered with flat slabs
+reaching from one side to the other. The lava rocks near the
+houses are carved into the resemblance of various animals and
+human faces, forming, probably, a kind of picture writing.
+Wooden tablets covered with various signs and figures have also
+been found. The only ancient implement discovered on the
+island is a kind of stone chisel, but it seems impossible that such
+large and numerous works could have been executed with such
+a tool. The present inhabitants of Easter Island know nothing
+of the construction of these remarkable works; and the entire
+subject of their existence in this small and remote island is a
+mystery.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTERN BENGAL AND ASSAM<a name="ar56" id="ar56"></a></span>, a province of British India,
+which was constituted out of Assam and the eastern portion of
+Bengal on the 16th of October 1905. Area 111,569 sq. m.; pop.
+(1901) 30,961,459. It is situated between 20° 45&prime; and 28° 17&prime; N.,
+and between 87° 48&prime; and 97° 5&prime; E. The province, as thus reconstituted,
+consists of the Bengal districts of Dacca, Mymensingh,
+Faridpur, Backergunje, Tippera, Noakhali, Chittagong,
+Chittagong Hill Tracts, Rajshahi, Dinajpur, Jalpaiguri, Rangpur,
+Bogra, Pabna, Malda, and the native states of Kuch Behar
+and Hill Tippera; and the whole of the former area of Assam
+consisting of the districts of Goalpara, Kamrup, Darrang,
+Nowgong, Sibsagar, Lakhimpur, Sylhet, Cachar, Garo Hills,
+Khasi and Jaintia Hills, Naga Hills and Lushai Hills. It is
+bounded on the N. by Bhutan, on the W. by Burma, on the S. by
+Burma and the Bay of Bengal, and on the E. by Bengal. The
+line of demarcation between Bengal and the new province begins
+at the frontier of Bhutan, east of Darjeeling, runs south-west to
+Sahibganj on the Ganges and thence follows the course of the
+Ganges down to the deltaic branch, called the Haringhata,
+which leaves the main stream above Goalanda, and the course of
+the latter, which runs south into the Bay of Bengal. The capital
+of the province is Dacca, and its chief port is Chittagong.</p>
+
+<p>The Bengal districts which were transferred to Eastern Bengal
+and Assam comprised northern and eastern Bengal, the most
+prosperous and least overcrowded portion of Bengal. The land
+there is less densely populated, wages are higher and food
+cheaper, and the rainfall more copious and more regular, while
+the staple crops of jute, tobacco and rice command a higher price
+relative to the rent of the land than in Behar or other parts of
+Bengal. The population are largely Mahommedans and of a more
+virile stock than the Bengali proper. Northern Bengal corresponds
+almost exactly with the Rajshahi division and lies within
+the boundaries of the Ganges and Brahmaputra rivers. It
+contains much high land of a stiff red clay, with an undulating
+surface covered for the most part with scrub jungle. The
+inhabitants are Indo-Chinese, not Indo-Aryans as in Bengal
+proper, and are Mahommedan by religion instead of Hindu.
+Eastern Bengal consists of the Dacca and Chittagong divisions
+which are mainly Bengali in race and Hindu in religion. For the
+Assamese districts see <span class="sc"><a href="#artlinks">Assam</a></span>. The province as a whole contains
+18,036,688 Mahommedans and 12,036,538 Hindus. In language
+27,272,895 of the inhabitants speak Bengali, 1,349,784 speak
+Assamese, and the remainder Hindi and various hill dialects,
+Manipuri, Bodo, Khasi and Garo. The administration is in the
+hands of a lieutenant-governor, assisted by a legislative council
+of fifteen members. Under him are five commissioners, and
+financial matters are regulated by a board of revenue consisting
+of two members.</p>
+
+<p>The constitution of the new province arose out of the fact that
+Bengal had grown too unwieldy for the administration of a single
+lieutenant-governor. In 1868 Sir Stafford Northcote drew
+attention to the greatly augmented demands that the outlying
+portions of Bengal made on the time and labour of the government.
+At that time the population of the province was between
+40 and 50 millions, and the question was left in abeyance until
+1903, when the population had risen to 78½ millions. In the
+meantime the importance of rendering Assam a self-contained
+and independent administration with a service of its own, and
+of providing for its future commercial expansion, had arisen.
+These two considerations led Lord Curzon to propose that Bengal
+should be lopped of territory both on its eastern and western
+borders, and that all the districts east of the Brahmaputra should
+be constituted into a separate province. This proposal was
+bitterly opposed by the Hindus of Bengal on the ground that it
+would destroy the unity of the Bengali race; and their agitation
+was associated with the <i>Swadeshi</i> (own country) movement for
+the boycott of British goods.</p>
+
+<p>After the constitution of the province in October 1905, the
+agitation in Eastern Bengal increased. Public meetings of protest
+were held, vernacular broadsheets containing scandalous
+<span class="pagenum"><a name="page831" id="page831"></a>831</span>
+attacks on the British authorities were circulated, schoolboys
+and others were organized and drilled as so-called &ldquo;national
+volunteers,&rdquo; and employed as pickets to prevent the sale of
+British goods. Such was the state of things when Sir J. Bampfylde
+Fuller entered on his office as first lieutenant-governor of
+Eastern Bengal in January 1906. His reception was ominous.
+Representative bodies that were dominated by Hindus refused
+to vote the usual addresses of welcome, and non-official Hindus
+abstained from paying the customary calls. There were, however,
+no further overt signs of objection to the lieutenant-governor
+personally, and after a month or two&mdash;in spite of, or perhaps
+because of, his efforts to restrain sedition and to keep discipline
+in the schools&mdash;there was a decided change in the attitude of
+Hindu opinion. At Dacca, in July, for instance, the reception at
+Government House was attended by large numbers of Bengali
+gentlemen, who assured the lieutenant-governor that &ldquo;the
+trouble was nearly ended.&rdquo; The agitation was, in fact, largely
+artificial, the work of Calcutta lawyers, journalists and
+schoolmasters; the mass of the people, naturally law-abiding,
+was unmoved by it so long as the government showed a firm
+hand; while the Mussulmans, who formed a large proportion of
+the whole, saw in the maintenance of the partition and of the
+prestige of the British government the guarantees of their own
+security.</p>
+
+<p>All seemed to be going well when an unfortunate difference of
+opinion occurred between the lieutenant-governor and the
+central government, resulting in the resignation of Sir Bampfylde
+Fuller (August 1906) and in ulterior consequences destined
+to be of far-reaching import. The facts are briefly as follows.
+Acting on a report of Dr P. Chatterji, inspector of schools, dated
+January 2, 1906, the lieutenant-governor, on the 10th of February,
+addressed a letter to the registrar of Calcutta University recommending
+that the privilege of affiliation to the university should
+be withdrawn from the Banwarilal and Victoria high schools at
+Sirajganj in Pabna, as a punishment for the seditious conduct
+of both pupils and teachers. Apart from numerous cases of
+illegal interference with trade and of disorder in the streets
+reported against the students, two specific outrages of a serious
+character were instanced as having occurred on the 15th of
+November: the raiding of a cart laden with English cloth
+belonging to Marwari traders, and a cowardly assault by some
+40 or 50 lads on the English manager of the Bank of Bengal.
+These outrages &ldquo;were not the result of thoughtlessness or sudden
+excitement, but were the outcome of a regularly organized
+scheme, set on foot and guided by the masters of these schools,
+for employing the students in enforcing a boycott.&rdquo; All attempts
+to discover and punish the offenders had been frustrated by the
+refusal of the school authorities to take action, and in the opinion
+of the lieutenant-governor the only course open was to apply the
+remedy suggested in the circular letter addressed to magistrates
+and collectors (October 10, 1905) by Mr R.W. Carlyle, the officiating
+chief secretary to the government of Bengal, directing them,
+in the event of students taking any part in political agitation,
+boycotting and the like, to inform the heads of schools or colleges
+concerned that, unless they prevented such action being taken
+by the boys attending their institutions, their grant-in-aid and the
+privilege of competing for scholarships and of receiving scholarship-holders
+would be withdrawn, and that the university would
+be asked to disaffiliate their institutions.</p>
+
+<p>The reply, dated July 5th, from the secretary in the home
+department of the government of India, was&mdash;to use Sir
+Bampfylde&rsquo;s own later expression&mdash;to throw him over. It was
+likely that a difference of opinion in the syndicate of the university
+would arise as to the degree of culpability that attached
+to the proprietors of the schools; in the event of the syndicate
+taking any &ldquo;punitive action,&rdquo; the matter was certain to be raised
+in the senate, and would lead to an acrimonious public discussion,
+in which the partition of Bengal and the administration of the
+new province would be violently attacked; and in the actual
+state of public opinion in Bengal it seemed to the government of
+India highly inexpedient that such a debate should take place.
+&ldquo;Collective punishment,&rdquo; too, &ldquo;would be liable to be misconstrued
+in England,&rdquo; and the government preferred to rely
+on the gradual effect of the new university regulations, which
+aimed &ldquo;at discouraging the participation of students in political
+movements by enforcing the responsibility of masters and the
+managing committees of schools for maintaining discipline.&rdquo;</p>
+
+<p>On receipt of this communication Sir Bampfylde Fuller at
+once tendered his resignation to the viceroy (July 15). He
+pointed out that to withdraw from the position taken up would
+be &ldquo;concession, not in the interests of education, but to those
+people in Calcutta who have been striving to render my government
+impossible, in order to discredit the partition&rdquo;; that
+previous concessions had had merely provocative effects, and
+that were he to give way in this matter his authority would be so
+weakened that he would be unable to maintain order in the
+country. On the 3rd of August, after some days of deliberation,
+the viceroy telegraphed saying that he was &ldquo;unable to reconsider
+the orders sent,&rdquo; and accepting Sir Bampfylde&rsquo;s resignation.
+By the Anglo-Indian press the news was received with something
+like consternation, the <i>Times of India</i> describing the resignation
+as one of the gravest blunders ever committed in the history of
+British rule in India, and as a direct incentive to the forces of
+disquiet, disturbance and unrest. Equally emphatic was the
+verdict of the Mussulman community forming two-thirds of the
+population of Eastern Bengal. On the 7th of August, the day of
+Sir Bampfylde Fuller&rsquo;s departure from Dacca, a mass-meeting
+of 30,000 Mahommedans was held, which placed on record their
+disapproval of a system of government &ldquo;which maintains no
+continuity of policy,&rdquo; and expressed its feeling that the lowering
+of British prestige must &ldquo;alienate the sympathy of a numerically
+important and loyal section of His Majesty&rsquo;s subjects&rdquo;; and
+many meetings of Mussulmans subsequently passed resolutions
+to the same general effect. The <i>Akhbar-i-Islam</i>, the organ of
+Bombay Mussulman opinion, deplored the &ldquo;unwise step&rdquo;
+taken by the government, and ascribed it to Lord Minto&rsquo;s fear
+of the Babu press, a display of weakness of which the Babus
+would not be slow to take advantage.</p>
+
+<p>This latter prophecy was not slow in fulfilling itself. So early
+as the 8th of August Calcutta was the scene of several large
+demonstrations at which the Swadeshi vow was renewed, and
+at which resolutions were passed declining to accept the partition
+as a settled fact, and resolving on the continuance of the agitation.
+The tone of the Babu press was openly exultant: &ldquo;We have
+read the familiar story of the Russian traveller and the wolves,&rdquo;
+said a leading Indian newspaper in Calcutta. &ldquo;The British
+government follows a similar policy. First the little babies
+were offered up in the shape of the <i>Bande Mataram</i> circular
+and the Carlyle circular. Now a bigger boy has gone in the
+person of our own Joseph. Courage, therefore, O wolves!
+Press on and the horse will soon be yours to devour! Afterwards
+the traveller himself will alone be left.&rdquo;<a name="fa1e" id="fa1e" href="#ft1e"><span class="sp">1</span></a> The task before the
+new lieutenant-governor of Eastern Bengal, the Hon. L. Hare,
+was obviously no easy one. The encouragement given to sedition
+by the weakness of the government in this case was shown by
+later events in Bengal and elsewhere (see <span class="sc"><a href="#artlinks">India</a></span>: <i>History, ad fin.</i>).</p>
+
+<p>For the early history of the various portions of the province see
+<span class="sc"><a href="#artlinks">Bengal</a></span> and <span class="sc"><a href="#artlinks">Assam</a></span>.</p>
+
+<div class="condensed">
+<p>See Sir James Bourdillon, <i>The Partition of Bengal</i> (Society of Arts,
+1905); official blue-books on <i>The Reconstitution of the Provinces of
+Bengal and Assam</i> (Cd. 2658 and 2746), and <i>Resignation of Sir J.
+Bampfylde Fuller</i>, lieutenant-governor, &amp;c. (Cd. 3242). A long
+letter from Sir J.B. Fuller, headed <i>J&rsquo;accuse</i>, attacking the general
+policy of the Indian government in regard to the seditious propaganda,
+appeared in <i>The Times</i> of June 6, 1908.</p>
+</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1e" id="ft1e" href="#fa1e"><span class="fn">1</span></a> Quoted by Mr F.S.P. Lely in <i>The Times</i> of November 22, 1906.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EASTERN QUESTION, THE<a name="ar57" id="ar57"></a></span>, the expression used in diplomacy
+from about the time of the congress of Verona (1822) to comprehend
+the international problems involved in the decay of the
+Turkish empire and its supposed impending dissolution. The
+essential questions that are involved are so old that historians
+commonly speak of the &ldquo;Eastern Question&rdquo; in reference to
+events that happened long before the actual phrase was coined.
+But, wherever used, it is always the Turkish Question, the
+<span class="pagenum"><a name="page832" id="page832"></a>832</span>
+generic term in which subsidiary issues, <i>e.g.</i> the Greek, Armenian
+or Macedonian questions, are embraced. That a phrase of so
+wide and loose a nature should have been stereotyped in so
+narrow a sense is simply the outcome of the conditions under
+which it was invented. To the European diplomatists of the
+first half of the 19th century the Ottoman empire was still the
+only East with which they were collectively brought into contact.
+The rivalry of Great Britain and Russia in Persia had not
+yet raised the question of the Middle East; still less any
+ambitions of Germany in the Euphrates valley. The immense
+and incalculable problems involved in the rise of Japan, the
+awakening of China, and their relations to the European powers
+and to America&mdash;known as the Far Eastern Question&mdash;are
+comparatively but affairs of yesterday.</p>
+
+<p>The Eastern Question, though its roots are set far back in
+history&mdash;in the ancient contest between the political and intellectual
+ideals of Greece and Asia, and in the perennial rivalry
+of the powers for the control of the great trade routes to the
+East&mdash;dates in its modern sense from the treaty of Kuchuk
+Kainarji in 1774, which marked the definitive establishment of
+Russia as a Black Sea power and formed the basis of her special
+claims to interfere in the affairs of the Ottoman empire. The
+compact between Napoleon and the emperor Alexander I. at
+Tilsit (1807) marked a new phase, which culminated in 1812 in
+the treaty of Bucharest, in which Russia definitely appeared
+as the protector of the Christian nationalities subject to the
+Ottoman sultan.</p>
+
+<p>The attitude of the various powers in the Eastern Question
+was now defined. Russia, apart from her desire to protect the
+Orthodox nationalities subject to the Ottoman power, aimed
+at owning or controlling the straits by which alone she could
+find an outlet to the Mediterranean and the ocean beyond.
+Austria, once the champion of Europe against the Turk, saw in
+the Russian advance on the Danube a greater peril than any to
+be feared from the moribund Ottoman power, and made the
+maintenance of the integrity of Turkey a prime object of her
+policy. She was thus brought into line with Great Britain,
+whose traditional friendship with Turkey was strengthened by
+the rise of a new power whose rapid advance threatened the
+stability of British rule in India. But though Austria, Great
+Britain and presently France, were all equally interested in
+maintaining the Ottoman empire, the failure of the congress of
+Vienna in 1815 to take action in the matter of a guarantee of
+Turkey, and the exclusion of the Sultan from the Holy
+Alliance, seemed to endorse the claim of Russia to regard
+the Eastern Question as &ldquo;her domestic concern&rdquo; in which
+&ldquo;Europe&rdquo; had no right to interfere. The revolt of the Greeks
+(1821) put this claim to the test; by the treaty of Adrianople
+(1829) Russia stipulated for their autonomy as part of the price
+of peace, but the powers assembled in conference at London
+refused to recognize this settlement, and the establishment
+of Greece as an independent kingdom (1832) was really aimed
+at the pretensions and the influence of Russia. These reached
+their high-water mark in the treaty of Unkiar Skelessi (July 8th,
+1832). It was no longer a question of the partition of Turkey
+or of a Russian conquest of Constantinople, but of the deliberate
+degradation by Russia of the Ottoman empire into a weak state
+wholly dependent upon herself. The ten years&rsquo; crisis (1831-1841)
+evoked by the revolt of Mehemet Ali, pasha of Egypt, thus
+resolved itself into a diplomatic struggle between Russia and the
+other powers to maintain or to recover influence at Constantinople.
+The Russian experiment of maintaining the integrity of Turkey
+while practically treating her as a vassal state, ended with the
+compromise of 1841; and the emperor Nicholas I. reverted to
+the older idea of expelling the Turks from Europe. The Eastern
+Question, however, slumbered until, in 1851, the matter of the
+Holy Places was raised by Napoleon III., involving the whole
+question of the influence in Ottoman affairs of France under
+the capitulations of 1740 and of Russia under the treaty of 1774.
+The Crimean War followed and in 1856 the treaty of Paris, by
+which the powers hoped to stem the tide of Russian advance and
+establish the integrity of a reformed Ottoman state. Turkey
+was now for the first time solemnly admitted to the European
+concert. The next critical phase was opened in 1871, when
+Russia took advantage of the collapse of France to denounce the
+Black Sea clauses of the treaty of 1856. The renewal of an
+aggressive policy thus announced to the world soon produced
+a new crisis in the Eastern Question, which had meanwhile
+become complicated by the growth of Pan-Slav ideals in eastern
+Europe. In 1875 a rising in Herzegovina gave evidence of a state
+of feeling in the Balkan peninsula which called for the intervention
+of Europe, if a disastrous war were to be prevented. But this
+intervention, embodied in the &ldquo;Andrassy Note&rdquo; (December 1875)
+and the Berlin memorandum (May 1876), met with the stubborn
+opposition of Turkey, where the &ldquo;young Turks&rdquo; were beginning
+to oppose a Pan-Islamic to the Pan-Slav ideal. The Russo-Turkish
+War of 1877-78 followed, concluded by the treaty of San
+Stefano, the terms of which were modified in Turkey&rsquo;s favour by
+the congress of Berlin (1878), which marks the beginning of the
+later phase of the Eastern Question. Between Russia and Turkey
+it interposed, in effect, a barrier of independent (Rumania, Servia)
+and quasi-independent (Bulgaria) states, erected with the counsel
+and consent of collective Europe. It thus, while ostensibly
+weakening, actually tended to strengthen the Ottoman power of
+resistance.</p>
+
+<p>The period following the treaty of Berlin is coincident with the
+reign of Sultan Abd-ul-Hamid II. The international position of
+the Ottoman empire was strengthened by the able, if Machiavellian,
+statecraft of the sultan; while the danger of disruption from
+within was lessened by the more effective central control made
+possible by railways, telegraphs, and the other mechanical improvements
+borrowed from western civilization. With the
+spread of the Pan-Islamic movement, moreover, the undefined
+authority of the sultan as caliph of Islam received a fresh
+importance even in countries beyond the borders of the Ottoman
+empire, while in countries formerly, or nominally still, subject
+to it, it caused, and promised to cause, incalculable trouble.</p>
+
+<p>The Eastern Question thus developed, in the latter years of
+the 19th century, from that of the problems raised by the impending
+break-up of a moribund empire, into the even more complex
+question of how to deal with an empire which showed vigorous
+evidence of life, but of a type of life which, though on all sides
+in close touch with modern European civilization, was incapable
+of being brought into harmony with it. The belief in the imminent
+collapse of the Ottoman dominion was weakened almost
+to extinction; so was the belief, which inspired the treaty of
+1856, in the capacity of Turkey to reform and develop itself
+on European lines. But the Ottoman empire remained, the
+mistress of vast undeveloped wealth. The remaining phase of the
+Eastern Question, if we except the concerted efforts to impose
+good government on Macedonia in the interests of European
+peace, or the side issues in Egypt and Arabia, was the rivalry
+of the progressive nations for the right to exploit this wealth.
+In this rivalry Germany, whose interest in Turkey even so late
+as the congress of Berlin had been wholly subordinate, took a
+leading part, unhampered by the traditional policies or the
+humanitarian considerations by which the interests of the older
+powers were prejudiced. The motives of German intervention
+in the Eastern Question were ostensibly commercial; but the
+Bagdad railway concession, postulating for its ultimate success
+the control of the trade route by way of the Euphrates valley,
+involved political issues of the highest moment and opened up a
+new and perilous phase of the question of the Middle East.</p>
+
+<p>This was the position when in 1908 an entirely new situation
+was created by the Turkish revolution. As the result of the
+patient and masterly organization of the &ldquo;young Turks,&rdquo; combined
+with the universal discontent with the rule of the sultan
+and the palace <i>camarilla</i>, the impossible seemed to be achieved,
+and the heterogeneous elements composing the Ottoman empire
+to be united in the desire to establish a unified state on the constitutional
+model of the West. The result on the international
+situation was profound. Great Britain hastened to re-knit the
+bonds of her ancient friendship with Turkey; the powers,
+without exception, professed their sympathy with the new régime.
+<span class="pagenum"><a name="page833" id="page833"></a>833</span>
+The establishment of a united Turkey on a constitutional and
+nationalist basis was, however, not slow in producing a fresh
+complication in the Eastern Question. Sooner or later the
+issue was sure to be raised of the status of those countries, still
+nominally part of the Ottoman empire, but in effect independent,
+like Bulgaria, or subject to another state, like Bosnia and
+Herzegovina. The cutting of the Gordian knot by Austria&rsquo;s
+annexation of Bosnia and Herzegovina, and by the proclamation
+of the independence of Bulgaria, and of Prince Ferdinand&rsquo;s
+assumption of the old title of tsar (king), threatened to raise the
+Eastern Question once more in its acutest form. The international
+concert defined in the treaty of Berlin had been rudely
+shaken, if not destroyed; the denunciation by Austria, without
+consulting her co-signatories, of the clauses of the treaty affecting
+herself seemed to invalidate all the rest; and in the absence of
+the restraining force of a united concert of the great powers, free
+play seemed likely once more to be given to the rival ambitions
+of the Balkan nationalities, the situation being complicated by
+the necessity for the dominant party in the renovated Turkish
+state to maintain its prestige. During the anxious months
+that followed the Austrian <i>coup</i>, the efforts of diplomacy were
+directed to calming the excitement of Servians, Montenegrins
+and the Young Turks, and to considering a European conference
+in which the <i>fait accompli</i> should be regularized in accordance
+with the accepted canons of international law. The long delay
+in announcing the assembly of the conference proved the extreme
+difficulty of arriving at any satisfactory basis of settlement;
+and though the efforts of the powers succeeded in salving the
+wounded pride of the Turks, and restraining the impetuosity
+of the Serbs and Montenegrins, warlike preparations on the part
+of Austria continued during the winter of 1908-1909, being
+justified by the agitation in Servia, Montenegro and the annexed
+provinces. It was not till April 1909 (see <span class="sc"><a href="#artlinks">Europe</a></span>: <i>ad fin.</i>)
+that the crisis was ended, through the effectual backing given
+by Germany to Austria; and Russia, followed by England and
+France, gave way and assented to what had been done.</p>
+
+<div class="condensed">
+<p>See <span class="sc"><a href="#artlinks">Turkey</a></span>: <i>History</i>, where cross-references to the articles on
+the various phases of the Eastern Question will be found, together
+with a bibliography. See also E. Driault, <i>La Question d&rsquo;orient depuis
+son origine</i> (Paris, 1898), a comprehensive sketch of the whole subject,
+including the Middle and Far East.</p>
+</div>
+<div class="author">(W. A. P.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EAST GRINSTEAD<a name="ar58" id="ar58"></a></span>, a market town in the East Grinstead
+parliamentary division of Sussex, England, 30 m. S. by E. from
+London by the London, Brighton &amp; South Coast railway. Pop. of
+urban district (1901) 6094. St Swithin&rsquo;s church contains, among
+numerous ancient memorials, one of the iron memorial slabs
+(1507) peculiar to certain churches of Sussex, and recalling the
+period when iron was extensively worked in the district. There
+may be noticed Sackville College (an almshouse founded in 1608),
+and St Margaret&rsquo;s home and orphanage, founded by the Rev.
+John Mason Neale (1818-1866), warden of Sackville College.
+Brewing and brick and tile making are carried on. In the
+vicinity (near Forest Row station) is the golf course of the Royal
+Ashdown Forest Golf Club.</p>
+
+<p>The hundred of East Grinstead (Grenestede, Estgrensted)
+was in the possession of the count of Mortain in 1086, but no
+mention of a vill or manor of East Grinstead is made in the
+Domesday Survey. In the reign of Henry III. the hundred was
+part of the honour of Aquila, then in the king&rsquo;s hands. The
+honour was granted by him to Peter of Savoy, through whom
+it passed to his niece Queen Eleanor. In the next reign the
+king&rsquo;s mother held the borough of East Grinstead as parcel of
+the honour of Aquila. East Grinstead was included in a grant
+by Edward III. to John of Gaunt, duke of Lancaster, and it
+remained part of the duchy of Lancaster until James I. granted
+the borough to Sir George Rivers, through whom it was obtained
+by the Sackvilles, earls of Dorset. East Grinstead was a borough
+by prescription. In the 16th century it was governed by an
+alderman, bailiff and constable. It returned two members to
+parliament from 1307 until 1832, but was disenfranchised by
+the Reform Act. In 1285 the king ordered that his market at
+Grenestede should be held on Saturday instead of Sunday, and
+in 1516 the inhabitants of the town were granted a market each
+week on Saturday and a fair every year on the eve of St Andrew
+and two days following. Charles I. granted the earl of Dorset
+a market on Thursday instead of the Saturday market, and fairs
+on the 16th of April and the 26th of September every year.
+Thursday is still the market-day, and cattle-fairs are now held
+on the 21st of April and the 11th of December.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST HAM<a name="ar59" id="ar59"></a></span>, a municipal borough in the southern parliamentary
+division of Essex, England, contiguous to West Ham,
+and thus forming geographically part of the eastward extension of
+London. Pop. (1901) 96,018. Its modern growth has been very
+rapid, the population being in the main of the artisan class.
+There are some chemical and other factories. The ancient
+parish church of St Mary Magdalen retains Norman work in the
+chancel, which terminates in an eastern apse. There is a monument
+for Edmund Neville who claimed the earldom of Westmorland
+in the 17th century, and William Stukeley, the antiquary,
+was buried in the churchyard. East Ham was incorporated
+in 1904, and among its municipal undertakings is a technical
+college (1905). The corporation consists of a mayor, 6 aldermen
+and 18 councillors. Area, 3320½ acres.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTHAMPTON<a name="ar60" id="ar60"></a></span>, a township of Hampshire county, Mass.,
+U.S.A., in the Connecticut Valley. Pop. (1900) 5603, of whom
+1731 were foreign-born; (1905) 6808; (1910) 8524. It is served by
+the Boston &amp; Maine, and the New York, New Haven &amp; Hartford
+railways, and by interurban electric railways. The township
+is generally level, and is surrounded by high hills. In Easthampton
+are a free public library and Williston Seminary; the
+latter, one of the oldest and largest preparatory schools in New
+England, was founded in 1841 by the gifts of Samuel Williston
+(1795-1874) and Emily Graves Williston (1797-1885). Mr and
+Mrs Williston built up the industry of covering buttons with
+cloth, at first doing the work by hand, then (1827) experimenting
+with machinery, and in 1848 building a factory for making and
+covering buttons. As the soil was fertile and well watered, the
+township had been agricultural up to this time. It is now chiefly
+devoted to manufacturing. Among its products are cotton goods,
+especially mercerised goods, for the manufacture of which it has
+one of the largest plants in the country; rubber, thread, elastic
+fabrics, suspenders and buttons. Parts of Northampton and
+Southampton were incorporated as the &ldquo;district&rdquo; of Easthampton
+in 1785; it became a township in 1809, and in 1841
+and 1850 annexed parts of Southampton.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST HAMPTON<a name="ar61" id="ar61"></a></span>, a township of Suffolk county, New York,
+in the extreme S.E. part of Long Island, occupying the peninsula
+of Montauk, and bounded on the S. and E. by the Atlantic Ocean,
+and on the N. by Block Island Sound, Gardiner&rsquo;s Bay and
+Peconic Bay. Pop. (1900) 3746; (1905) 4303; (1910) 4722.
+The township, 25 m. long and 8 m. at its greatest width from
+north to south, has an irregular north coast-line and a very
+regular south coast-line. The surface is rougher to the west
+where there are several large lakes, notably Great Pond, 2 m.
+long. The scenery is picturesque and the township is much
+frequented by artists. Montauk Lighthouse, on Turtle Hill,
+was first built in 1795. At Montauk, after the Spanish-American
+War, was Camp Wikoff, a large U.S. military camp. The
+township is served by the southern division of the Long Island
+railway, the terminus of which is Montauk. Other villages of
+the township, all summer resorts, are: Promised Land, Amagansett,
+East Hampton and Sag Harbor; the last named, only partly
+in the township, was incorporated in 1803 and had a population
+of 1969 in 1900, and 3084 in 1910. Silverware and watch cases
+are manufactured here. From Sag Harbor, which is a port of
+entry, a daily steamer runs to New York city. The village
+received many gifts in 1906-1908 from Mrs Russell Sage. Most
+of the present township was bought from the Indians (Montauks,
+Corchaugs and Shinnecocks) in 1648 for about £30, through the
+governors of Connecticut and New Haven, by nine Massachusetts
+freemen, mostly inhabitants of Lynn, Massachusetts.
+With twenty other families they settled here in 1649, calling the
+place Maidstone, from the old home of some of the settlers in
+Kent; but as early as 1650 the name East Hampton was used
+in reference to the earlier settlement of South Hampton. Until
+<span class="pagenum"><a name="page834" id="page834"></a>834</span>
+1664, when all Long Island passed to the duke of York, the
+government was by town meeting, autonomous and independent
+except for occasional appeals to Connecticut. In 1683 Gardiner&rsquo;s
+Island, settled by Lion Gardiner in 1639 and so one of the first
+English settlements in what is now New York state, was made
+a part of Long Island and of East Hampton township. The
+English settlements in East Hampton were repeatedly threatened
+by pirates and privateers, and there are many stories of treasure
+buried by Captain Kidd on Gardiner&rsquo;s Island and on Montauk
+Point. The Clinton Academy, opened in East Hampton village
+in 1785, was long a famous school. Of the church built here
+in 1653 (first Congregational and after 1747 Presbyterian in
+government), Lyman Beecher was pastor in 1799-1810; and in
+East Hampton were born his elder children. Whale fishing was
+begun in East Hampton in 1675, when four Indians were engaged
+by whites in off-shore whaling; but Sag Harbor, which was first
+settled in 1730 and was held by the British after the battle of
+Long Island as a strategic naval and shipping point, became the
+centre of the whaling business. The first successful whaling
+voyage was made from Sag Harbor in 1785, and although the
+Embargo ruined the fishing for a time, it revived during 1830-1850.
+Cod and menhaden fishing, the latter for the manufacture
+of fish-oil and guano, were important for a time, but in the
+second half of the 19th century Sag Harbor lost its commercial
+importance.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST INDIA COMPANY<a name="ar62" id="ar62"></a></span>, an incorporated company for exploiting
+the trade with India and the Far East. In the 17th
+and 18th centuries East India companies were established by
+England, Holland, France, Denmark, Scotland, Spain, Austria
+and Sweden. By far the most important of these was the
+English East India Company, which became the dominant
+power in India, and only handed over its functions to the British
+Government in 1858 (see also <span class="sc"><a href="#artlinks">Dutch East India Company</a></span>,
+<span class="sc"><a href="#artlinks">Ostend Company</a></span>).</p>
+
+<p>The English East India Company was founded at the end of
+the 16th century in order to compete with the Dutch merchants,
+who had obtained a practical monopoly of the trade
+with the Spice Islands, and had raised the price of
+<span class="sidenote">English East India Co.</span>
+pepper from 3s. to 8s. per &#8468;. Queen Elizabeth incorporated
+it by royal charter, dated December 31, 1600,
+under the title of &ldquo;The Governor and Company of Merchants
+of London, trading into the East Indies.&rdquo; This charter conferred
+the sole right of trading with the East Indies, <i>i.e.</i> with all countries
+lying beyond the Cape of Good Hope or the Straits of Magellan,
+upon the company for a term of 15 years. Unauthorized interlopers
+were liable to forfeiture of ships and cargo. There were
+125 shareholders in the original East India Company, with a
+capital of £72,000: the first governor was Sir Thomas Smythe.
+The early voyages of the company, from 1601 to 1612, are distinguished
+as the &ldquo;separate voyages,&rdquo; because the subscribers
+individually bore the cost of each voyage and reaped the whole
+profits, which seldom fell below 100%. After 1612 the voyages
+were conducted on the joint stock system for the benefit of the
+company as a whole. These early voyages, whose own narratives
+may be read in Purchas, pushed as far as Japan, and established
+friendly relations at the court of the Great Mogul. In
+1610-1611 Captain Hippon planted the first English factories
+on the mainland of India, at Masulipatam and at Pettapoli in
+the Bay of Bengal. The profitable nature of the company&rsquo;s
+trade had induced James I. to grant subsidiary licences to private
+traders; but in 1609 he renewed the company&rsquo;s charter &ldquo;for
+ever,&rdquo; though with a proviso that it might be revoked on three
+years&rsquo; notice if the trade should not prove profitable to the realm.</p>
+
+<p>Meanwhile friction was arising between the English and
+Dutch East India Companies. The Dutch traders considered
+that they had prior rights in the Far East, and their
+ascendancy in the Indian Archipelago was indeed
+<span class="sidenote">English and Dutch disputes.</span>
+firmly established on the basis of territorial dominion
+and authority. In 1613 they made advances to the
+English company with a suggestion for co-operation, but the
+offer was declined, and the next few years were fertile in disputes
+between the armed traders of both nations. In 1619 was ratified
+a &ldquo;treaty of defence&rdquo; to prevent disputes between the English
+and Dutch companies. When it was proclaimed in the East,
+hostilities solemnly ceased for the space of an hour, while the
+Dutch and English fleets, dressed out in all their flags and with
+yards manned, saluted each other; but the treaty ended in the
+smoke of that stately salutation, and perpetual and fruitless
+contentions between the Dutch and English companies went on
+just as before. In 1623 these disputes culminated in the &ldquo;massacre
+of Amboyna,&rdquo; where the Dutch governor tortured and
+executed the English residents on a charge of conspiring to seize
+the fort. Great and lasting indignation was aroused in England,
+but it was not until the time of Cromwell that some pecuniary
+reparation was exacted for the heirs of the victims. The
+immediate result was that the English company tacitly admitted
+the Dutch claims to a monopoly of the trade in the Far East,
+and confined their operations to the mainland of India and the
+adjoining countries.</p>
+
+<p>The necessity of good ships for the East Indian trade had
+led the company in 1609 to construct their dockyard at Deptford,
+from which, as Monson observes, dates &ldquo;the increase
+of great ships in England.&rdquo; Down to the middle of the
+<span class="sidenote">The East Indiamen.</span>
+19th century, the famous &ldquo;East Indiamen&rdquo; held
+unquestioned pre-eminence among the merchant vessels of the
+world. Throughout the 17th century they had to be prepared
+at any moment to fight not merely Malay pirates, but the armed
+trading vessels of their Dutch, French and Portuguese rivals.
+Many such battles are recorded in the history of the East India
+Company, and usually with successful results.</p>
+
+<p>It was not until it had been in existence for more than a century
+that the English East India Company obtained a practical
+monopoly of the Indian trade. In 1635, a year after
+the Great Mogul had granted it the liberty of trading
+<span class="sidenote">The acquisition of territory.</span>
+throughout Bengal, Charles I. issued a licence to
+Courten&rsquo;s rival association, known as &ldquo;the Assada
+Merchants,&rdquo; on the ground that the company had neglected
+English interests. The piratical methods of their rivals disgraced
+the company with the Mogul officials, and a <i>modus vivendi</i> was
+only reached in 1649. In 1657 Cromwell renewed the charter of
+1609, providing that the Indian trade should be in the hands of
+a single joint stock company. The new company thus formed
+bought up the factories, forts and privileges of the old one. It
+was further consolidated by the fostering care of Charles II.,
+who granted it five important charters. From a simple trading
+company, it grew under his reign into a great chartered company&mdash;to
+use the modern term&mdash;with the right to acquire territory,
+coin money, command fortresses and troops, form alliances, make
+war and peace, and exercise both civil and criminal jurisdiction.
+It is accordingly in 1689, when the three presidencies of Bengal,
+Madras and Bombay had lately been established, that the ruling
+career of the East India Company begins, with the passing by
+its directors of the following resolution for the guidance of the
+local governments in India:&mdash;&ldquo;The increase of our revenue
+is the subject of our care, as much as our trade; &rsquo;tis that must
+maintain our force when twenty accidents may interrupt our
+trade; &rsquo;tis that must make us a nation in India; without that
+we are but a great number of interlopers, united by His Majesty&rsquo;s
+royal charter, fit only to trade where nobody of power thinks
+it their interest to prevent us; and upon this account it is that
+the wise Dutch, in all their general advices that we have seen,
+write ten paragraphs concerning their government, their civil
+and military policy, warfare, and the increase of their revenue,
+for one paragraph they write concerning trade.&rdquo; From this
+moment the history of the transactions of the East India Company
+becomes the history of British India (see <span class="sc"><a href="#artlinks">India</a></span>: <i>History</i>).
+Here we shall only trace the later changes in the constitution and
+powers of the ruling body itself.</p>
+
+<p>The great prosperity of the company under the Restoration,
+and the immense profits of the Indian trade, attracted a number
+of private traders, both outside merchants and dismissed
+or retired servants of the company, who came
+<span class="sidenote">The interlopers.</span>
+to be known as &ldquo;interlopers.&rdquo; In 1683 the case of
+Thomas Sandys, an interloper, raised the whole question of the
+<span class="pagenum"><a name="page835" id="page835"></a>835</span>
+royal prerogative to create a monopoly of the Indian trade.
+The case was tried by Judge Jeffreys, who upheld the royal
+prerogative; but in spite of his decision the custom of interloping
+continued and laid the foundation of many great fortunes.
+By 1691 the interlopers had formed themselves into a new
+society, meeting at Dowgate, and rivalling the old company;
+the case was carried before the House of Commons, which declared
+in 1694 that &ldquo;all the subjects of England have equal
+right to trade to the East Indies unless prohibited by act of
+parliament.&rdquo; This decision led up to the act of 1698, which
+created a new East India Company in consideration of a loan
+of two millions to the state. The old company subscribed
+£315,000 and became the dominant factor in the new body;
+while at the same time it retained its charter for three years,
+its factories, forts and assured position in India. The rivalry
+between the two companies continued both in England and in
+India, until they were finally amalgamated by a tripartite indenture
+between the companies and Queen Anne (1702), which
+was ratified under the Godolphin Award (1708). Under this
+award the company was to lend the nation £3,200,000, and its
+exclusive privileges were to cease at three years&rsquo; notice after
+this amount had been repaid. But by this time the need for
+permanence in the Indian establishment began to be felt, while
+parliament would not relinquish its privilege of &ldquo;milking&rdquo;
+the company from time to time. In 1712 an act was passed continuing
+the privileges of the company even after their fund should
+be redeemed; in 1730 the charter was prolonged until 1766,
+and in 1742 the term was extended until 1783 in return for the
+loan of a million. This million was required for the war with
+France, which extended to India and involved the English and
+French companies there in long-drawn hostilities, in which the
+names of Dupleix and Clive became prominent.</p>
+
+<p>So long as the company&rsquo;s chief business was that of trade, it
+was left to manage its own affairs. The original charter of
+Elizabeth had placed its control in the hands of a
+governor and a committee of twenty-four, and this
+<span class="sidenote">The company and the crown.</span>
+arrangement subsisted in essence down to the time of
+George III. The chairman and court of directors in
+London exercised unchecked control over their servants in India.
+But after Clive&rsquo;s brilliant victory at Plassey (1757) had made
+the company a ruling power in India, it was felt to be necessary
+that the British government should have some control over the
+territories thus acquired. Lord North&rsquo;s Regulating Act (1773)
+raised the governor of Bengal&mdash;Warren Hastings&mdash;to the rank
+of governor-general, and provided that his nomination, though
+made by a court of directors, should in future be subject to the
+approval of the crown; in conjunction with a council of four,
+he was entrusted with the power of peace and war; a supreme
+court of judicature was established, to which the judges were
+appointed by the crown; and legislative power was conferred
+on the governor-general and his council. Next followed Pitt&rsquo;s
+India Bill (1784), which created the board of control, as a
+department of the English government, to exercise political,
+military and financial superintendence over the British possessions
+in India. This bill first authorized the historic phrase
+&ldquo;governor-general in council.&rdquo; From this date the direction
+of Indian policy passed definitely from the company to the
+governor-general in India and the ministry in London. In 1813
+Lord Liverpool passed a bill which further gave the board of
+control authority over the company&rsquo;s commercial transactions,
+and abolished its monopoly of Indian trade, whilst leaving it
+the monopoly of the valuable trade with China, chiefly in tea.
+Finally, under Earl Grey&rsquo;s act of 1833, the company was deprived
+of this monopoly also. Its property was then secured on the
+Indian possessions, and its annual dividends of ten guineas per
+£100 stock were made a charge upon the Indian revenue. Henceforward
+the East India Company ceased to be a trading concern
+and exercised only administrative functions. Such a position
+could not, in the nature of things, be permanent, and the great
+cataclysm of the Indian Mutiny was followed by the entire
+transference of Indian administration from the company to the
+crown, on the 2nd of August 1858.</p>
+
+<div class="condensed">
+<p>See <i>Purchas his Pilgrimes</i> (ed. 1905), vols. 2, 3, 4, 5, for the charter
+of Elizabeth and the early voyages; Sir W.W. Hunter, <i>History
+of British India</i> (1899); Beckles Willson, <i>Ledger and Sword</i> (1903);
+Sir George Birdwood, <i>Report on the Old Records of the India Office</i>
+(1879); <i>The East India Company&rsquo;s First Letter Book</i> (1895), <i>Letters
+Received by the East India Company from its Servants in the East</i>,
+ed. Foster, (1896 ff.). See also the interesting memorial volume
+<i>Relics of the Honourable East India Company</i> (ed. Griggs, 1909),
+letterpress by Sir G. Birdwood and W. Foster.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EAST INDIES<a name="ar63" id="ar63"></a></span>, a name formerly applied vaguely, in its widest
+sense, to the whole area of India, Further India and the Malay
+Archipelago, in distinction from the West Indies, which, at the
+time of their discovery, were taken to be the extreme parts of
+the Indian region. The term &ldquo;East Indies&rdquo; is still sometimes
+applied to the Malay Archipelago (<i>q.v.</i>) alone, and the phrase
+&ldquo;Dutch East Indies&rdquo; is commonly used to denote the Dutch
+possessions which constitute the greater part of that archipelago.
+The Dutch themselves use the term <i>Nederlandsch-Indië</i>.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTLAKE, SIR CHARLES LOCK<a name="ar64" id="ar64"></a></span> (1793-1865), English
+painter, was born on the 17th of November 1793 at Plymouth,
+where his father, a man of uncommon gifts but of indolent
+temperament, was solicitor to the admiralty and judge advocate
+of the admiralty court. Charles was educated (like Sir Joshua
+Reynolds) at the Plympton grammar-school, and in London at
+the Charterhouse. Towards 1809, partly through the influence
+of his fellow-Devonian Haydon, of whom he became a pupil,
+he determined to be a painter; he also studied in the Royal
+Academy school. In 1813 he exhibited in the British Institution
+his first picture, a work of considerable size, &ldquo;Christ restoring
+life to the Daughter of Jairus.&rdquo; In 1814 he was commissioned
+to copy some of the paintings collected by Napoleon in the
+Louvre; he returned to England in 1815, and practised portrait-painting
+at Plymouth. Here he saw Napoleon a captive on
+the &ldquo;Bellerophon&rdquo;; from a boat he made some sketches of
+the emperor, and he afterwards painted, from these sketches
+and from memory, a life-sized full-length portrait of him (with
+some of his officers) which was pronounced a good likeness;
+it belongs to the marquess of Lansdowne. In 1817 Eastlake
+went to Italy; in 1819 to Greece; in 1820 back to Italy, where
+he remained altogether fourteen years, chiefly in Rome and in
+Ferrara.</p>
+
+<p>In 1827 he exhibited at the Royal Academy his picture of the
+Spartan Isidas, who (as narrated by Plutarch in the life of
+Agesilaus), rushing naked out of his bath, performed prodigies
+of valour against the Theban host. This was the first work that
+attracted much notice to the name of Eastlake, who in consequence
+obtained his election as A.R.A.; in 1830, when he
+returned to England, he was chosen R.A. In 1850 he succeeded
+Shee as president of the Royal Academy, and was knighted.
+Prior to this, in 1841, he had been appointed secretary to the
+royal commission for decorating the Houses of Parliament, and
+he retained this post until the commission was dissolved in 1862.
+In 1843 he was made keeper of the National Gallery, a post
+which he resigned in 1847 in consequence of an unfortunate
+purchase that roused much animadversion, a portrait erroneously
+ascribed to Holbein; in 1855, director of the same institution,
+with more extended powers. During his directorship he purchased
+for the gallery 155 pictures, mostly of the Italian schools.
+He became also a D.C.L. of Oxford, F.R.S., a chevalier of the
+Legion of Honour, and member of various foreign academies.</p>
+
+<p>In 1849 he married Miss Elizabeth Rigby, who had already then
+become known as a writer (<i>Letters from the Baltic</i>, 1841; <i>Livonian
+Tales</i>, 1846; <i>The Jewess</i>, 1848) and as a contributor to the
+<i>Quarterly Review</i>. Lady Eastlake (1809-1893) had for some years
+been interested in art subjects, and after her marriage she
+naturally devoted more attention to them, translating Waagen&rsquo;s
+<i>Treasures of Art in Great Britain</i> (1854-1857), and completing
+Mrs Jameson&rsquo;s <i>History of our Lord in Works of Art</i>. In 1865
+Sir Charles Eastlake fell ill at Milan; and he died at Pisa on the
+24th of December in the same year. Lady Eastlake, who survived
+him for many years, continued to play an active part as a
+writer on art (<i>Five Great Painters</i>, 1883, &amp;c.), and had a large
+circle of friends among the most interesting men and women of
+the day. In 1880 she published a volume of <i>Letters from France</i>
+<span class="pagenum"><a name="page836" id="page836"></a>836</span>
+(describing events in Paris during 1789), written by her father,
+Edward Rigby (1747-1821), a distinguished Norwich doctor
+who was known also for his practical interest in agriculture, and
+who is said to have made known the flying shuttle to Norwich
+manufacturers.</p>
+
+<p>As a painter, Sir Charles Eastlake was gentle, harmonious,
+diligent and correct; lacking fire of invention or of execution;
+eclectic, without being exactly imitative; influenced rather by a
+love of ideal grace and beauty than by any marked bent of
+individual power or vigorous originality. Among his principal
+works (which were not numerous, 51 being the total exhibited in
+the Academy) are: 1828, &ldquo;Pilgrims arriving in sight of Rome&rdquo;
+(repeated in 1835 and 1836, and perhaps on the whole his
+<i>chef-d&rsquo;&oelig;uvre</i>); 1829, &ldquo;Byron&rsquo;s Dream&rdquo; (in the Tate Gallery);
+1834, the &ldquo;Escape of Francesco di Carrara&rdquo; (a duplicate in
+the Tate Gallery); 1841, &ldquo;Christ Lamenting over Jerusalem&rdquo;
+(ditto); 1843, &ldquo;Hagar and Ishmael&rdquo;; 1845, &ldquo;Comus&rdquo;; 1849,
+&ldquo;Helena&rdquo;; 1851, &ldquo;Ippolita Torelli&rdquo;; 1853, &ldquo;Violante&rdquo;;
+1855, &ldquo;Beatrice.&rdquo; These female heads, of a refined semi-ideal
+quality, with something of Venetian glow of tint, are the most
+satisfactory specimens of Eastlake&rsquo;s work to an artist&rsquo;s eye.
+He was an accomplished and judicious scholar in matters of art,
+and published, in 1840, a translation of Goethe&rsquo;s <i>Theory of
+Colours</i>; in 1847 (his chief literary work) <i>Materials for a History
+of Oil-Painting</i>, especially valuable as regards the Flemish school;
+in 1848, <i>Contributions to the Literature of the Fine Arts</i> (a second
+series was edited by Lady Eastlake in 1870, and accompanied by a
+Memoir from her pen); in 1851 and 1855, translated editions of
+Kugler&rsquo;s <i>History of the Italian School of Painting</i>, and <i>Handbook
+of Painting</i> (new edition, by Lady Eastlake, 1874).</p>
+
+<div class="condensed">
+<p>See W. Cosmo Monkhouse, <i>Pictures by Sir Charles Eastlake, with
+biographical and critical Sketch</i> (1875).</p>
+</div>
+<div class="author">(W. M. R.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EAST LIVERPOOL<a name="ar65" id="ar65"></a></span>, a city of Columbiana county, Ohio, U.S.A.,
+on the Ohio river, about 106 m. S.E. of Cleveland. Pop. (1890)
+10,956; (1900) 16,485, of whom 2112 were foreign-born; (1910
+census) 20,357. It is served by the Pennsylvania railway, by
+river steamboats, and by interurban electric lines. Next to
+Trenton, New Jersey, East Liverpool is the most important
+place in the United States for the manufacture of earthenware
+and pottery, 4859 out of its 5228 wage-earners, or 92.9%,
+being employed in this industry in 1905, when $5,373,852 (83.5%
+of the value of all its factory products) was the value of the
+earthenware and pottery. No other city in the United States
+is so exclusively devoted to the manufacture of pottery; in 1908
+there were 32 potteries in the city and its immediate vicinity.
+The manufacture of white ware, begun in 1872, is the most
+important branch of the industry&mdash;almost half of the &ldquo;cream-coloured,&rdquo;
+white granite ware and semivitreous porcelain produced
+in the United States in 1905 (in value, $4,344,468 out of
+$9,195,703) being manufactured in East Liverpool. Though
+there are large clay deposits in the vicinity, very little of it can be
+used for crockery, and most of the clay used in the city&rsquo;s potteries
+is obtained from other states; some of it is imported from Europe.
+After 1872 a large number of skilled English pottery-workers
+settled in the city. The city&rsquo;s product of pottery, terra-cotta
+and fireclay increased from $2,137,063 to $4,105,200 from 1890
+to 1900, and in the latter year almost equalled that of Trenton,
+N.J., the two cities together producing more than half (50.9%)
+of the total pottery product of the United States; in 1905 East
+Liverpool and Trenton together produced 42.1% of the total
+value of the country&rsquo;s pottery product. The municipality owns
+and operates its water-works. East Liverpool was settled in
+1798, and was incorporated in 1834.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST LONDON<a name="ar66" id="ar66"></a></span>, a town of the Cape province, South Africa, at
+the mouth of the Buffalo river, in 33° 1&prime; S. 27° 55&prime; E., 543 m.
+E.N.E. of Cape Town by sea and 666 m. S. of Johannesburg by
+rail. Pop. (1904) 25,220, of whom 14,674 were whites. The town
+is picturesquely situated on both sides of the river, which is
+spanned by a combined road and railway bridge. The railway
+terminus and business quarter are on the east side on the top of
+the cliffs, which rise 150 ft. above the river. In Oxford Street,
+the chief thoroughfare, is the town hall, a handsome building
+erected in 1898. Higher up a number of churches and a school
+are grouped round Vincent Square, a large open space. In consequence
+of the excellent sea bathing, and the beauty of the river
+banks above the town, East London is the chief seaside holiday
+resort of the Cape province. The town is the entrepot of a rich
+agricultural district, including the Transkei, Basutoland and the
+south of Orange Free State, and the port of the Cape nearest
+Johannesburg. It ranks third among the ports of the province.
+The roadstead is exposed and insecure, but the inner harbour,
+constructed at a cost of over £2,000,000, is protected from all
+winds. A shifting sand bar lies at the mouth of the river, but
+the building of training walls and dredging have increased the
+minimum depth of water to 22 ft. From the east bank of the
+Buffalo a pier and from the west bank a breakwater project into
+the Indian Ocean, the entrance being 450 ft. wide, reduced
+between the training walls to 250 ft. There is extensive wharf
+accommodation on both sides of the river, and steamers of over
+8000 tons can moor alongside. There is a patent slip capable
+of taking vessels of 1000 tons dead weight. An aerial steel
+ropeway from the river bank to the town greatly facilitates the
+delivery of cargo. The imports are chiefly textiles, hardware
+and provisions, the exports mainly wool and mohair. The
+rateable value of the town in 1908 was £4,108,000, and the
+municipal rate 1<span class="spp">5</span>&frasl;<span class="suu">8</span>d.</p>
+
+<p>East London owes its foundation to the necessities of the
+Kaffir war of 1846-1847. The British, requiring a port nearer
+the scene of war than those then existing, selected a site at the
+mouth of the Buffalo river, and in 1847 the first cargo of military
+stores was landed. A fort, named Glamorgan, was built, and the
+place permanently occupied. Around this military post grew
+up the town, known at first as Port Rex. Numbers of its inhabitants
+are descendants of German immigrants who settled in
+the district in 1857. The prosperity of the town dates from the
+era of railway and port development in the last decade of the
+19th century. In 1875 the value of the exports was £131,803
+and that of the imports £552,033. In 1904 the value of the
+exports was £1,165,938 and that of the imports £4,688,415. In
+1907 the exports, notwithstanding a period of severe trade
+depression, were valued at £1,475,355, but the imports had fallen
+to £3,354,633.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EASTON<a name="ar67" id="ar67"></a></span>, a city and the county-seat of Northampton county,
+Pennsylvania, U.S.A., at the confluence of the Lehigh river and
+Bushkill Creek with the Delaware, about 60 m. N. of Philadelphia.
+Pop. (1890) 14,481; (1900) 25,238, of whom 2135 were foreign-born;
+(1910 census) 28,523. Easton is served by the Central
+of New Jersey, the Lehigh Valley, the Lehigh &amp; Hudson River
+and the Delaware, Lackawanna &amp; Western railways, and is
+connected by canals with the anthracite coal region to the
+north-west and with Bristol, Pa. A bridge across the Delaware
+river connects it with Phillipsburg, New Jersey, which is served
+by the Pennsylvania railway. The city is built on rolling ground,
+commanding pleasant views of hill and river scenery. Many
+fine residences overlook city and country from the hillsides, and
+a Carnegie library is prominent among the public buildings.
+Lafayette College, a Presbyterian institution opened in 1832,
+is finely situated on a bluff north of the Bushkill and Delaware.
+The college provides the following courses of instruction:
+graduate, classical, Latin scientific, general scientific, civil
+engineering, electrical engineering, mining engineering and
+chemical; in 1908 it had 38 instructors and 442 students, 256
+of whom were enrolled in the scientific and engineering courses.
+Overlooking the Bushkill is the Easton Cemetery, in which is
+the grave of George Taylor (1716-1781), a signer of the Declaration
+of Independence, with a monument of Italian marble to
+his memory. Among the city&rsquo;s manufactures are silk, hosiery
+and knit goods, flour, malt liquors, brick, tile, drills, lumber and
+planing mill products and organs; in 1905 the value of all the
+factory products was $5,654,594, of which $2,290,598, or 40.5%,
+was the value of the silk manufactures. Easton is the commercial
+centre of an important mining region, which produces, in particular,
+iron ore, soapstone, cement, slate and building stone.
+The municipality owns and operates an electric-lighting plant.
+<span class="pagenum"><a name="page837" id="page837"></a>837</span>
+Easton was a garden spot of the Indians, and here, because they
+would not negotiate elsewhere, several important treaties were
+made between 1756 and 1762 during the French and Indian War.
+The place was laid out in 1752, and was made the county-seat
+of the newly erected county. It was incorporated as a borough
+in 1789, received a new borough charter in 1823, and in 1887 was
+chartered as a city. South Easton was annexed in 1898.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST ORANGE<a name="ar68" id="ar68"></a></span>, a city of Essex county, New Jersey, U.S.A.,
+in the north-eastern part of the state, adjoining the city of Newark,
+and about 12 m. W. of New York city. Pop. (1890) 13,282;
+(1900) 21,506, of whom 3950 were foreign-born and 1420 were
+negroes; (1910 census) 34,371. It is served by the Morris &amp;
+Essex division of the Delaware, Lackawanna &amp; Western railway
+and by the Orange branch of the Erie (the former having
+four stations&mdash;Ampere, Grove Street, East Orange and Brick
+Church), and is connected with Newark, Orange and West
+Orange by electric line. The city covers an area of about 4 sq. m.,
+and has broad, well-paved streets, bordered with fine shade trees
+(under the jurisdiction of a &ldquo;Shade Tree Commission&rdquo;). It is
+primarily a residential suburb of New York and Newark, and
+has many beautiful homes; with Orange, West Orange and
+South Orange it forms virtually one community, popularly
+known as &ldquo;the Oranges.&rdquo; The public school system is excellent,
+and the city has a Carnegie library (1903), with more than
+22,000 volumes in 1907. Among the principal buildings are
+several attractive churches, the city hall, and the club-house of
+the Woman&rsquo;s Club of Orange. The principal manufactures of
+East Orange are electrical machinery, apparatus, and supplies
+(the factory of the Crocker-Wheeler Co. being here&mdash;in a part
+of the city known as &ldquo;Ampere&rdquo;) and pharmaceutical materials.
+The total value of the city&rsquo;s factory products in 1905 was
+$2,326,552. East Orange has a fine water-works system, which
+it owns and operates; the water supply is obtained from artesian
+wells at White Oaks Ridge, in the township of Milburn (about
+10 m. from the city hall); thence the water is pumped to a steel
+reinforced reservoir (capacity 5,000,000 gallons) on the mountain
+back of South Orange. In 1863 the township of East Orange
+was separated from the township of Orange, which, in turn, had
+been separated from the township of Newark in 1806. An act
+of the New Jersey legislature in 1895 created the office of township
+president, with power of appointment and veto. Four years
+later East Orange was chartered as a city.</p>
+
+<div class="condensed">
+<p>See H. Whittemore, <i>The Founders and Builders of the Oranges</i>
+(Newark, 1896).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EASTPORT<a name="ar69" id="ar69"></a></span>, a city and port of entry of Washington county,
+Maine, U.S.A., co-extensive with Moose Island in Passamaquoddy
+Bay, about 190 m. E.N.E. of Portland. Pop. (1890) 4908; (1900)
+5311 (1554 foreign-born); (1910) 4961. It is served by the
+Washington County railway, and by steamboat lines to Boston,
+Portland and Calais. It is the most eastern city of the United
+States, and is separated from the mainland by a narrow
+channel, which is spanned by a bridge. The harbour is well
+protected from the winds, and the tide, which rises and falls
+here about 25 ft., prevents it from being obstructed with ice.
+The city is built on ground sloping gently to the water&rsquo;s edge,
+and commands delightful views of the bay, in which there are
+several islands. Its principal industry is the canning of sardines;
+there are also clam canneries. Shoes, mustard, decorated tin,
+and shooks are manufactured, and fish and lobsters are shipped
+from here in the season. The city is the port of entry for the
+customs district of Passamaquoddy; in 1908 its imports were
+valued at $994,961, and its exports at $1,155,791. Eastport
+was first settled about 1782 by fishermen; it became a port of
+entry in 1790, was incorporated as a town in 1798, and was
+chartered as a city in 1893. It was a notorious place for
+smuggling under the Embargo Acts of 1807 and 1808. On the
+11th of July 1814, during the war of 1812, it was taken by the
+British. As the British government claimed the islands of
+Passamaquoddy Bay under the treaty of 1783, the British
+forces retained possession of Eastport after the close of the war
+and held it under martial law until July 1818, when it was
+surrendered in accordance with the decision rendered in
+November 1817 by commissioners appointed under Article IV.
+of the treaty of Ghent (1814), this decision awarding Moose
+Island, Dudley Island and Frederick Island to the United States
+and the other islands, including the Island of Grand Manan in
+the Bay of Fundy, to Great Britain.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST PROVIDENCE<a name="ar70" id="ar70"></a></span>, a township of Providence county,
+Rhode Island, U.S.A., on the E. side of Providence river, opposite
+Providence. Pop. (1890) 8422; (1900) 12,138, of whom 2067
+were foreign-born; (1910 census) 15,808. Area, 12½ sq. m.
+It is served by the New York, New Haven &amp; Hartford railway.
+It has a rolling surface and contains several villages, one of which,
+known as Rumford, has important manufactories of chemicals
+and electrical supplies. South of this village, along the river
+bank, are several attractive summer resorts, Hunt&rsquo;s Mills,
+Silver Spring, Riverside, Vanity Fair, Kettle Point and Bullock&rsquo;s
+Point being prominent among them. In 1905 the factory
+products of the township were valued at $5,035,288. The
+oyster trade is important. It was within the present limits of
+this township that Roger Williams established himself in the
+spring of 1636, until he learned that the place was within the
+jurisdiction of the Plymouth Colony. About 1644 it was settled
+by a company from Weymouth as a part of a town of Rehoboth.
+In 1812 Rehoboth was divided, and the west part was made the
+township of Seekonk. Finally, in 1861, it was decided that the
+west part of Seekonk belonged to Rhode Island, and in the
+following year that part was incorporated as the township of
+East Providence.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAST PRUSSIA<a name="ar71" id="ar71"></a></span> (<i>Ost-Preussen</i>), the easternmost province of
+the kingdom of Prussia, bounded on the N. by the Baltic, on the
+E. and S.W. by Russia and Russian Poland, and on the W. by
+the Prussian province of West Prussia. It has an area of 14,284
+sq. m., and had, in 1905, a population of 2,025,741. It shares in
+the general characteristics of the great north German plain,
+but, though low, its surface is by no means absolutely flat, as the
+southern half is traversed by a low ridge or plateau, which attains
+a height of 1025 ft. at a point near the western boundary of the
+province. This plateau, here named the Prussian Seenplatte, is
+thickly sprinkled with small lakes, among which is the Spirding
+See, 46 sq. m. in extent and the largest inland lake in the Prussian
+monarchy. The coast is lined with low dunes or sandhills, in
+front of which lie the large littoral lakes or lagoons named the
+Frisches Haff and the Kurisches Haff. The first of these receives
+the waters of the Nogat and the Pregel, and the other those
+of the Memel or Niemen. East Prussia is the coldest part of
+Germany, its mean annual temperature being about 44° F.,
+while the mean January temperature of Tilsit is only 25°. The
+rainfall is 24 in. per annum. About half the province is under
+tillage; 18% is occupied by forests, and about 23% by meadows
+and pastures. The most fertile soil is found in the valleys of the
+Pregel and the Memel, but the southern slopes of the Baltic
+plateau and the district to the north of the Memel consist in
+great part of sterile moor, sand and bog. The chief crops are rye,
+oats and potatoes, while flax is cultivated in the district of
+Ermeland, between the Passarge and the upper Alle. East
+Prussia is the headquarters of the horse-breeding of the country,
+and contains the principal government stud of Trakehnen;
+numerous cattle are also fattened on the rich pastures of the river-valleys.
+The extensive woods in the south part of the province
+harbour a few wolves and lynxes, and the elk is still preserved
+in the forest of Ibenhorst, near the Kurisches Haff. The fisheries
+in the lakes and haffs are of some importance; but the only
+mineral product of note is amber, which is found in the peninsula
+of Samland in greater abundance than in any other part of the
+world. Manufactures are almost confined to the principal towns,
+though linen-weaving is practised as a domestic industry.
+Commerce is facilitated by canals connecting the Memel and
+Pregel and also the principal lakes, but is somewhat hampered
+by the heavy dues exacted at the Russian frontier. A brisk
+foreign trade is carried on through the seaports of Königsberg,
+the capital of the province, and Memel, the exports consisting
+mainly of timber and grain.</p>
+
+<p>The population of the province was in 1900 1,996,626, and
+<span class="pagenum"><a name="page838" id="page838"></a>838</span>
+included 1,698,465 Protestants, 269,196 Roman Catholics and
+13,877 Jews. The Roman Catholics are mainly confined to the
+district of Ermeland, in which the ordinary proportions of the
+confessions are completely reversed. The bulk of the inhabitants
+are of German blood, but there are above 400,000 Protestant
+Poles (Masurians or Masovians) in the south part of the province,
+and 175,000 Lithuanians in the north. As in other provinces
+where the Polish element is strong, East Prussia is somewhat
+below the general average of the kingdom in education. There
+is a university at Königsberg.</p>
+
+<div class="condensed">
+<p>See Lohmeyer, <i>Geschichte von Ost- und West-Preussen</i> (Gotha,
+1884); Brünneck, <i>Zur Geschichte des Kirchen-Patronats in Ost- und
+West-Preussen</i> (Berlin, 1902), and <i>Ost-Preussen, Land und Volk</i>
+(Stuttgart, 1901-1902).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EASTWICK, EDWARD BACKHOUSE<a name="ar72" id="ar72"></a></span> (1814-1883), British
+Orientalist, was born in 1814, a member of an Anglo-Indian
+family. Educated at Charterhouse and at Oxford, he joined
+the Bombay infantry in 1836, but, owing to his talent for
+languages, was soon given a political post. In 1843 he translated
+the Persian <i>Kessahi Sanján</i>, or <i>History of the Arrival of the
+Parsees in India</i>; and he wrote a <i>Life of Zoroaster</i>, a <i>Sindhi</i>
+vocabulary, and various papers in the transactions of the
+Bombay Asiatic Society. Compelled by ill-health to return to
+Europe, he went to Frankfort, where he learned German and
+translated Schiller&rsquo;s <i>Revolt of the Netherlands</i> and Bopp&rsquo;s <i>Comparative
+Grammar</i>. In 1845 he was appointed professor of
+Hindustani at Haileybury College. Two years later he published
+a Hindustani grammar, and, in subsequent years, a new edition
+of the <i>Gulistán</i>, with a translation in prose and verse, also an
+edition with vocabulary of the Hindi translation by Lallú Lál of
+Chatur Chuj Misr&rsquo;s <i>Prem Sagár</i>, and translations of the <i>Bagh-o-Bahar</i>,
+and of the <i>Anvár-i Suhaili</i> of Bídpáí. In 1851 he was
+elected a Fellow of the Royal Society. In 1857-1858 he edited
+<i>The Autobiography of Lútfullah</i>. He also edited for the Bible
+Society the Book of Genesis in the Dakhani language. From
+1860 to 1863 he was in Persia as secretary to the British Legation,
+publishing on his return <i>The Journal of a Diplomate</i>. In 1866
+he became private secretary to the secretary of state for India,
+Lord Cranborne (afterwards marquess of Salisbury), and in
+1867 went, as in 1864, on a government mission to Venezuela.
+On his return he wrote, at the request of Charles Dickens, for
+<i>All the Year Round</i>, &ldquo;Sketches of Life in a South American
+Republic.&rdquo; From 1868 to 1874 he was M.P. for Penryn and
+Falmouth. In 1875 he received the degree of M.A. with the
+franchise from the university of Oxford, &ldquo;as a slight recognition
+of distinguished services.&rdquo; At various times he wrote several
+of Murray&rsquo;s Indian hand-books. His last work was the <i>Kaisarnamah-i-Hind</i>
+(&ldquo;the lay of the empress&rdquo;), in two volumes
+(1878-1882). He died at Ventnor, Isle of Wight, on the 16th of
+July 1883.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EATON, DORMAN BRIDGMAN<a name="ar73" id="ar73"></a></span> (1823-1899), American lawyer,
+was born at Hardwick, Vermont, on the 27th of June 1823. He
+graduated at the university of Vermont in 1848 and at the
+Harvard Law School in 1850, and in the latter year was admitted
+to the bar in New York city. There he became associated in
+practice with William Kent, the son of the great chancellor, an
+edition of whose <i>Commentaries</i> he assisted in editing. Eaton
+early became interested in municipal and civil service reform.
+He was conspicuous in the fight against Tweed and his followers,
+by one of whom he was assaulted; he required a long period of
+rest, and went to Europe, where he studied the workings of
+the civil service in various countries. From 1873 to 1875 he
+was a member of the first United States Civil Service Commission.
+In 1877, at the request of President Hayes, he made a careful
+study of the British civil service, and three years later published
+<i>Civil Service in Great Britain</i>. He drafted the Pendleton Civil
+Service Act of 1883, and later became a member of the new
+commission established by it. He resigned in 1885, but was
+almost immediately reappointed by President Cleveland, and
+served until 1886, editing the 3rd and 4th <i>Reports</i> of the commission.
+He was an organizer (1878) of the first society for
+the furtherance of civil service reform in New York, of the
+National Civil Service Reform Association, and of the National
+Conference of the Unitarian Church (1865). He died in New York
+city on the 23rd of December 1899, leaving $100,000 each to
+Harvard and Columbia universities for the establishments of
+professorships in government. He was a legal writer and editor,
+and a frequent contributor to the leading reviews. In addition
+to the works mentioned he published <i>Should Judges be Elected?</i>
+(1873), <i>The Independent Movement in New York</i> (1880), <i>Term
+and Tenure of Office</i> (1882), <i>The Spoils System and Civil Service
+Reform</i> (1882), <i>Problems of Police Legislation</i> (1895) and <i>The
+Government of Municipalities</i> (1899).</p>
+
+<div class="condensed">
+<p>See the privately printed memorial volume, <i>Dorman B. Eaton</i>,
+1823-1899 (New York, 1900).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EATON, MARGARET O&rsquo;NEILL<a name="ar74" id="ar74"></a></span> (1796-1879), better known
+as <span class="sc">Peggy O&rsquo;Neill</span>, was the daughter of the keeper of a popular
+Washington tavern, and was noted for her beauty, wit and
+vivacity. About 1823, she married a purser in the United
+States navy, John B. Timberlake, who committed suicide while
+on service in the Mediterranean in 1828. In the following year
+she married John Henry Eaton (1790-1856), a Tennessee politician,
+at the time a member of the United States Senate.
+Senator Eaton was a close personal friend of President Jackson,
+who in 1829 appointed him secretary of war. This sudden
+elevation of Mrs Eaton into the cabinet social circle was resented
+by the wives of several of Jackson&rsquo;s secretaries, and charges
+were made against her of improper conduct with Eaton previous
+to her marriage to him. The refusal of the wives of the cabinet
+members to recognize the wife of his friend angered President
+Jackson, and he tried in vain to coerce them. Eventually, and
+partly for this reason, he almost completely reorganized his
+cabinet. The effect of the incident on the political fortunes
+of the vice-president, John C. Calhoun, whose wife was one of
+the recalcitrants, was perhaps most important. Partly on this
+account, Jackson&rsquo;s favour was transferred from Calhoun to
+Martin Van Buren, the secretary of state, who had taken Jackson&rsquo;s
+side in the quarrel and had shown marked attention to
+Mrs Eaton, and whose subsequent elevation to the vice-presidency
+and presidency through Jackson&rsquo;s favour is no doubt
+partly attributable to this incident. In 1836 Mrs Eaton accompanied
+her husband to Spain, where he was United States
+minister in 1836-1840. After the death of her husband she
+married a young Italian dancing-master, Antonio Buchignani,
+but soon obtained a divorce from him. She died in Washington
+on the 8th of November 1879.</p>
+
+<div class="condensed">
+<p>See James Parton&rsquo;s <i>Life of Andrew Jackson</i> (New York, 1860).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EATON, THEOPHILUS<a name="ar75" id="ar75"></a></span> (<i>c.</i> 1590-1658), English colonial governor
+in America, was born at Stony Stratford, Buckinghamshire,
+about 1590. He was educated in Coventry, became a
+successful merchant, travelled widely throughout Europe, and
+for several years was the financial agent of Charles I. in Denmark.
+He subsequently settled in London, where he joined the Puritan
+congregation of the Rev. John Davenport, whom he had known
+since boyhood. The pressure upon the Puritans increasing,
+Eaton, who had been one of the original patentees of the Massachusetts
+Bay colony in 1629, determined to use his influence and
+fortune to establish an independent colony of which his pastor
+should be the head. In 1637 he emigrated with Davenport to
+Massachusetts, and in the following year (March 1638) he and
+Davenport founded New Haven. In October 1639 a form of
+government was adopted, based on the <span class="correction" title="amended from Mosiac">Mosaic</span> Law, and Eaton
+was elected governor, a post which he continued to hold by annual
+re-election, first over New Haven alone, and after 1643 over the
+New Haven Colony or Jurisdiction, until his death at New Haven
+on the 7th of January 1658. His administration was embarrassed
+by constantly recurring disputes with the neighbouring
+Dutch settlements, especially after Stamford (Conn.) and Southold
+(Long Island) had entered the New Haven Jurisdiction, but his
+prudence and diplomacy prevented an actual outbreak of hostilities.
+He was prominent in the affairs of the New England
+Confederation, of which he was one of the founders (1643). In
+1655 he and Davenport drew up the code of laws, popularly
+known as the &ldquo;Connecticut Blue Laws,&rdquo; which were published
+<span class="pagenum"><a name="page839" id="page839"></a>839</span>
+in London in 1656 under the title <i>New Haven&rsquo;s Settling in New
+England and some Lawes for Government published for the Use of
+that Colony</i>.</p>
+
+<div class="condensed">
+<p>A sketch of his life appears in Cotton Mather&rsquo;s <i>Magnalia</i> (London,
+1702); see also J.B. Moore&rsquo;s &ldquo;Memoir of Theophilus Eaton&rdquo; in the
+<i>Collections</i> of the New York Historical Society, second series, vol. ii.
+(New York, 1849).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EATON, WILLIAM<a name="ar76" id="ar76"></a></span> (1764-1811), American soldier, was born
+in Woodstock, Connecticut, on the 23rd of February 1764. As
+a boy he served for a short time in the Continental army. He
+was a school teacher for several years, graduated at Dartmouth
+College in 1790, was clerk of the lower house of the Vermont
+legislature in 1791-1792, and in 1792 re-entered the army as a
+captain, later serving against the Indians in Ohio and Georgia.
+In 1797 he was appointed consul to Tunis, where he arrived in
+February 1799. In March 1799, with the consuls to Tripoli and
+Algiers, he negotiated alterations in the treaty of 1797 with
+Tunis. He rendered great service to Danish merchantmen by
+buying on credit several Danish prizes in Tunis and turning
+them over to their original owners for the redemption of his
+notes. In 1803 he quarrelled with the Bey, was ordered from
+the country, and returned to the United States to urge American
+intervention for the restoration of Ahmet Karamanli to the
+throne of Tripoli, arguing that this would impress the Barbary
+States with the power of the United States. In 1804 he returned
+to the Mediterranean as United States naval agent to the Barbary
+States with Barron&rsquo;s fleet. On the 23rd of February 1805 he
+agreed with Ahmet that the United States should undertake to
+re-establish him in Tripoli, that the expenses of the expedition
+should be repaid to the United States by Ahmet, and that Eaton
+should be general and commander-in-chief of the land forces in
+Ahmet&rsquo;s campaign; as the secretary of the navy had given the
+entire matter into the hands of Commodore Barron, and as
+Barron and Tobias Lear (1762-1816), the United States consul-general
+at Algiers and a diplomatic agent to conduct negotiations,
+had been instructed to consider the advisability of making
+arrangements with the existing government in Tripoli, Eaton far
+exceeded his authority. On the 8th of March he started for
+Derna across the Libyan desert from the Arab&rsquo;s Tower, 40 m. W.
+of Alexandria, with a force of about 500 men, including a few
+Americans, about 40 Greeks and some Arab cavalry. In the
+march of nearly 600 m. the camel-drivers and the Arab chiefs
+repeatedly mutinied, and Ahmet Pasha once put himself at the
+head of the Arabs and ordered them to attack Eaton. Ahmet
+more than once wished to give up the expedition. There were
+practically no provisions for the latter part of the march. On
+the 27th of April with the assistance of three bombarding cruisers
+Eaton captured Derna&mdash;an exploit commemorated by Whittier&rsquo;s
+poem <i>Derne</i>. On the 13th of May and on the 10th of June he
+successfully withstood the attacks of Tripolitan forces sent to
+dislodge him. On the 12th of June he abandoned the town upon
+orders from Commodore Rodgers, for Lear had made peace
+(4th June) with Yussuf, the <i>de facto</i> Pasha of Tripoli. Eaton
+returned to the United States, and received a grant of 10,000
+acres in Maine from the Massachusetts legislature. According to
+a deposition which he made in January 1807 he was approached
+by Aaron Burr (<i>q.v.</i>), who attempted to enlist him in his &ldquo;conspiracy,&rdquo;
+and wished him to win over the marine corps and to
+sound Preble and Decatur. As he received from the government,
+soon after making this deposition, about $10,000 to liquidate
+claims for his expense in Tripoli, which he had long pressed in
+vain, his good faith has been doubted. At Burr&rsquo;s trial at Richmond
+in 1807 Eaton was one of the witnesses, but his testimony
+was unimportant. In May 1807 he was elected a member of the
+Massachusetts House of Representatives, and served for one term.
+He died on the 1st of June 1811 in Brimfield, Massachusetts.</p>
+
+<div class="condensed">
+<p>See the anonymously published <i>Life of the Late Gen. William Eaton</i>
+(Brookfield, Massachusetts, 1813) by Charles Prentiss; C.C. Felton,
+&ldquo;Life of William Eaton&rdquo; in Sparks&rsquo;s <i>Library of American Biography</i>,
+vol. ix. (Boston, 1838); and Gardner W. Allen&rsquo;s <i>Our Navy and the
+Barbary Corsairs</i> (Boston, 1905).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EATON, WYATT<a name="ar77" id="ar77"></a></span> (1849-1896), American portrait and figure
+painter, was born at Philipsburg, Canada, on the 6th of May 1849.
+He was a pupil of the schools of the National Academy of Design,
+New York, and in 1872 went to Paris, where he studied in the
+École des Beaux-Arts under J.L. Gérôme. He made the
+acquaintance of J.F. Millet at Barbizon, and was also influenced
+by his friend Jules Bastien-Lepage. After his return to the
+United States in 1876 he became a teacher in Cooper Institute
+and opened a studio in New York city. He was one of the
+organizers (and the first secretary) of the Society of American
+Artists. Among his portraits are those of William Cullen
+Bryant and Timothy Cole, the wood engraver (&ldquo;The Man with
+the Violin&rdquo;). Eaton died at Newport, Rhode Island, on the 7th
+of June 1896.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAU CLAIRE<a name="ar78" id="ar78"></a></span>, a city and the county-seat of Eau Claire
+county, Wisconsin, U.S.A., on the Chippewa river, at the mouth
+of the Eau Claire, about 87 m. E. of St Paul. Pop. (1890)
+17,415; (1900) 17,517, of whom 4996 were foreign-born; (1910 census)
+18,310. It is served by the Chicago &amp; North-Western,
+the Chicago, Milwaukee &amp; St Paul, and the Wisconsin Central
+railways, and is connected by an electric line with Chippewa
+Falls (12 m. distant). The city has a Carnegie library with
+17,200 volumes in 1908, a Federal building, county court house,
+normal school and insane asylum. It has abundant water-power,
+and is an important lumber manufacturing centre;
+among its other manufactures are flour, wooden-ware, agricultural
+machinery, saw-mill machinery, logging locomotives,
+wood pulp, paper, linen, mattresses, shoes and trunks. The
+total value of factory products in 1905 was $3,601,558. The
+city is the principal wholesale and jobbing market for the prosperous
+Chippewa Valley. Eau Claire was first settled about
+1847, and was chartered as a city in 1872; its growth dates from
+the development of the north-western lumber trade in the decade
+1870-1880. In 1881 a serious strike necessitated the calling out of
+state militia for its suppression and the protection of property.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAU DE COLOGNE<a name="ar79" id="ar79"></a></span> (Ger. <i>Kölnisches Wasser</i>, &ldquo;Cologne
+water&rdquo;), a perfume, so named from the city of Cologne, where
+its manufacture was first established by an Italian, Johann (or
+Giovanni) Maria Farina (1685-1766), who settled at Cologne
+in 1709. The perfume gained a high reputation by 1766, and
+Farina associated himself with his nephew, to whose grandson
+the secret was ultimately imparted; the original perfume is
+still manufactured by members of this family under the name
+of the founder. The manufacture is, however, carried on at
+Cologne, and also in Italy, by other firms bearing the name
+Farina, and the scent has become part of the regular output of
+perfumers. The discovery has also been ascribed to a Paul de
+Feminis, who is supposed to have brought his recipe from Milan
+to Cologne, of which he became a citizen in 1690, and sold the
+perfume under the name <i>Eau admirable</i>, leaving the secret at
+his death to his nephew Johann Maria Farina. Certain of the
+Farinas claim to use his process. It was originally prepared
+by making an alcoholic infusion of certain flowers, pot-herbs,
+drugs and spices, distilling and then adding definite quantities
+of several vegetable essences. The purity and thorough blending
+of the ingredients are of the greatest importance. The original
+perfume is simulated and even excelled by artificial preparations.
+The oils of lemon, bergamot and orange are employed, together
+with the oils of neroli and rosemary in the better class. The
+common practice consists in dissolving the oils, in certain definite
+proportions based on experience, in pure alcohol and distilling,
+the distillate being diluted by rose-water.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAUX-BONNES<a name="ar80" id="ar80"></a></span>, a watering-place of south-western France,
+in the department of Basses-Pyrénées, 3½ m. S.E. of the small
+town of Laruns, the latter being 24 m. S. of Pau by rail. Pop.
+(1906) 610. Eaux-Bonnes is situated at a height of 2460 ft.
+at the entrance of a fine gorge, overlooking the confluence of
+two torrents, the Valentin and the Sourde. The village is well
+known for its sulphurous and saline mineral waters (first mentioned
+in the middle of the 14th century), which are beneficial
+in affections of the throat and lungs. They vary between
+50° and 90° F. in temperature, and are used for drinking and
+bathing. There are two thermal establishments, a casino and
+fine promenades.</p>
+
+<p><span class="pagenum"><a name="page840" id="page840"></a>840</span></p>
+
+<p>The watering-place of <span class="sc">Les Eaux-Chaudes</span> is 5 m. by road
+south-west of Eaux-Bonnes, in a wild gorge on the Gave d&rsquo;Ossau.
+The springs are sulphurous, varying in temperature from 52° to
+97° F., and are used in cases of rheumatism, certain maladies of
+women, &amp;c. The thermal establishment is a handsome marble
+building.</p>
+
+<p>There is fine mountain scenery in the neighbourhood of both
+places, the Pic de Ger near Eaux-Bonnes, commanding an
+extensive view. The valley of Ossau, one of the most beautiful in
+the Pyrenees, before the Revolution formed a community which,
+though dependent on Béarn, had its own legal organization,
+manners and costumes, the last of which are still to be seen on
+holidays.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAVES<a name="ar81" id="ar81"></a></span> (not a plural form as is sometimes supposed, but
+singular; O. Eng. <i>efes</i>, in Mid. High Ger. <i>obse</i>, Gothic <i>ubizwa</i>, a
+porch; connected with &ldquo;over&rdquo;), in architecture, the projecting
+edge of a sloping roof, which overhangs the face of the wall so
+as to throw off the water.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EAVESDRIP<a name="ar82" id="ar82"></a></span>, or <span class="sc">Eavesdrop</span>, that width of ground around
+a house or building which receives the rain water dropping from
+the eaves. By an ancient Saxon law, a landowner was forbidden
+to erect any building at less than 2 ft. from the boundary of his
+land, and was thus prevented from injuring his neighbour&rsquo;s house
+or property by the dripping of water from his eaves. The law
+of Eavesdrip has had its equivalent in the Roman <i>stillicidium</i>,
+which prohibited building up to the very edge of an estate.</p>
+
+<p>From the Saxon custom arose the term &ldquo;eavesdropper,&rdquo;
+<i>i.e.</i> any one who stands within &ldquo;the eavesdrop&rdquo; of a house,
+hence one who pries into others&rsquo; business or listens to secrets.
+At common law an eavesdropper was regarded as a common
+nuisance, and was presentable at the court leet, and indictable
+at the sheriff&rsquo;s tourn and punishable by fine and finding sureties
+for good behaviour. Though the offence of eavesdropping still
+exists at common law, there is no modern instance of a prosecution
+or indictment.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBBW VALE<a name="ar83" id="ar83"></a></span>, an urban district in the western parliamentary
+division of Monmouthshire, England, 21 m. N.W. of Newport
+on the Great Western, London &amp; North-Western and Rhymney
+railways. Pop. (1891) 17,312; (1901) 20,994. It lies near the
+head of the valley of the river Ebbw, at an elevation of nearly
+1000 ft., in a wild and mountainous mining district, which contains
+large collieries and important iron and steel works.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBEL, HERMANN WILHELM<a name="ar84" id="ar84"></a></span> (1820-1875), German philologist,
+was born at Berlin on the 10th of May 1820. He displayed
+in his early years a remarkable capacity for the study of
+languages, and at the same time a passionate fondness for music
+and poetry. At the age of sixteen he became a student at the
+university of Berlin, applying himself especially to philology,
+and attending the lectures of Böckh. Music continued to be the
+favourite occupation of his leisure hours, and he pursued the
+study of it under the direction of Marx. In the spring of 1838
+he passed to the university of Halle, and there began to apply
+himself to comparative philology under Pott. Returning in the
+following year to his native city, he continued this study as a
+disciple of Bopp. He took his degree in 1842, and, after spending
+his year of probation at the French Gymnasium of Berlin, he
+resumed with great earnestness his language studies. About
+1847 he began to study Old Persian. In 1852 he accepted a
+professorship at the Beheim-Schwarzbach Institution at Filehne,
+which post he held for six years. It was during this period that
+his studies in the Old Slavic and Celtic languages began. In
+1858 he removed to Schneidemühl, and there he discharged the
+duties of first professor for ten years. He was afterwards called
+to the chair of comparative philology at the university of Berlin.
+He died at Misdroy on the 19th of August 1875. The most
+important work of Dr Ebel in the field of Celtic philology is his
+revised edition of the <i>Grammatica Celtica</i> of Professor Zeuss,
+completed in 1871. This had been preceded by his treatises&mdash;<i>De
+verbi Britannici futuro ac conjunctivo</i> (1866), and <i>De Zeussii curis
+positis in Grammatica Celtica</i> (1869). He made many learned
+contributions to Kühn&rsquo;s <i>Zeitschrift für vergleichende Sprachforschung</i>,
+and to A. Schleicher&rsquo;s <i>Beiträge zur vergleichenden
+Sprachforschung</i>; and a selection of these contributions was
+translated into English by Sullivan, and published under the
+title of <i>Celtic Studies</i> (1863). Ebel contributed the Old Irish
+section to Schleicher&rsquo;s <i>Indogermanische Chrestomathie</i> (1869).
+Among his other works must be named <i>Die Lehnwörter der
+deutschen Sprache</i> (1856).</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBEL, JOHANN GOTTFRIED<a name="ar85" id="ar85"></a></span> (1764-1830), the author of the
+first real guide-book to Switzerland, was born at Züllichau
+(Prussia). He became a medical man, visited Switzerland for
+the first time in 1790, and became so enamoured of it that he
+spent three years exploring the country and collecting all kinds
+of information relating to it. The result was the publication
+(Zürich, 1793) of his <i>Anleitung auf die nützlichste und genussvollste
+Art in der Schweitz zu reisen</i> (2 vols.), in which he gave a complete
+account of the country, the General Information sections being
+followed by an alphabetically arranged list of places, with
+descriptions. It at once superseded all other works of the
+kind, and was the best Swiss guide-book till the appearance of
+&ldquo;Murray&rdquo; (1838). It was particularly strong on the geological
+and historical sides. The second (1804-1805) and third (1809-1810)
+editions filled four volumes, but the following (the 8th
+appeared in 1843) were in a single volume. The work was translated
+into French in 1795 (many later editions) and into English
+(by 1818). Ebel also published a work (2 vols., Leipzig, 1798-1802)
+entitled <i>Schilderungen der Gebirgsvölker der Schweiz</i>,
+which deals mainly with the pastoral cantons of Glarus and
+Appenzell. In 1801 he was naturalized a Swiss citizen, and
+settled down in Zürich. In 1808 he issued his chief geological
+work, <i>Über den Bau der Erde im Alpengebirge</i> (Zürich,
+2 vols.). He took an active share in promoting all that could
+make his adopted country better known, <i>e.g.</i> Heinrich Keller&rsquo;s
+map (1813), the building of a hotel on the Rigi (1816), and the
+preparation of a panorama from that point (1823). From
+1810 onwards he lived at Zürich, with the family of his friend,
+Conrad Escher von der Linth (1767-1823), the celebrated
+engineer.</p>
+<div class="author">(W. A. B. C.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBER, PAUL<a name="ar86" id="ar86"></a></span> (1511-1569), German theologian, was born
+at Kitzingen in Franconia, and was educated at Nuremberg
+and Wittenberg, where he became the close friend of Philip
+Melanchthon. In 1541 he was appointed professor of Latin
+grammar at Wittenberg, and in 1557 professor of the Old Testament.
+His range of learning was wide, and he published a
+handbook of Jewish history, a historical calendar intended to
+supersede the Roman Saints&rsquo; Calendar, and a revision of the
+Latin Old Testament. In the theological conflict of the time he
+played a large part, doing what he could to mediate between
+the extremists. From 1559 to the close of his life he was
+superintendent-general of the electorate of Saxony. He attained
+some fame as a hymn-writer, his best-known composition being
+&ldquo;Wenn wir in höchsten Nöthen sein.&rdquo; He died at Wittenberg
+on the 10th of December 1569.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBERBACH<a name="ar87" id="ar87"></a></span>, a town of Germany, in the grand-duchy of Baden,
+romantically situated on the Neckar, at the foot of the Katzenbuckel,
+19 m. E. of Heidelberg by the railway to Würzburg.
+Pop. (1900) 5857. It contains an Evangelical and a Roman
+Catholic church, a commercial and a technical school, and, in
+addition to manufacturing cigars, leather and cutlery, carries
+on by water an active trade in timber and wine. Eberbach was
+founded in 1227 by the German king Henry VII., who acquired
+the castle (the ruins of which overhang the town) from the
+bishop of Worms. It became an imperial town and passed later
+to the Palatinate.</p>
+
+<div class="condensed">
+<p>See Wirth, <i>Geschichte der Stadt Eberbach</i> (Stuttgart, 1864).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERBACH<a name="ar88" id="ar88"></a></span>, a famous Cistercian monastery of Germany, in
+the Prussian province of Hesse-Nassau, situated near Hattenheim
+in the Rheingau, 10 m. N.W. from Wiesbaden. Founded in
+1116 by Archbishop Adalbert of Mainz, as a house of Augustinian
+canons regular, it was bestowed by him in 1131 upon the Benedictines,
+but was shortly afterwards repurchased and conferred
+upon the Cistercian order. The Romanesque church (consecrated
+in 1186) contains numerous interesting monuments and tombs,
+notable among them being those of the archbishop of Mainz,
+<span class="pagenum"><a name="page841" id="page841"></a>841</span>
+Gerlach (d. 1371) and Adolph II. of Nassau (d. 1475). It was
+despoiled during the Thirty Years&rsquo; War, was secularized in 1803,
+and now serves as a house of correction. Its cellars contain some
+of the finest vintages of the Rhine wines of the locality.</p>
+
+<div class="condensed">
+<p>See Bär, <i>Diplomatische Geschichte der Abtei Eberbach</i> (Wiesb., 1851-1858
+and 1886, 3 vols.), and Schäfer, <i>Die Abtei Eberbach im Mittelalter</i>
+(Berlin, 1901).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERHARD<a name="ar89" id="ar89"></a></span>, surnamed <span class="sc">Im Bart</span> (<i>Barbatus</i>), count and
+afterwards duke of Württemberg (1445-1496), was the second
+son of Louis I., count of Württemberg-Urach (d. 1450), and
+succeeded his elder brother Louis II. in 1457. His uncle Ulrich V.,
+count of Württemberg-Stuttgart (d. 1480), acted as his guardian,
+but in 1459, assisted by Frederick I., elector palatine, he threw
+off this restraint, and undertook the government of the district
+of Urach as Count Eberhard V. He neglected his duties as a
+ruler and lived a reckless life until 1468, when he made a pilgrimage
+to Jerusalem. He visited Italy, became acquainted with
+some famous scholars, and in 1474 married Barbara di Gonzaga,
+daughter of Lodovico III., marquis of Mantua, a lady distinguished
+for her intellectual qualities. In 1482 he brought about
+the treaty of Münsingen with his cousin Eberhard VI., count of
+Württemberg-Stuttgart. By this treaty the districts of Urach
+and Stuttgart into which Württemberg had been divided in
+1437 were again united, and for the future the county was
+declared indivisible, and the right of primogeniture established.
+The treaty led to some disturbances, but in 1492 the sanction
+of the nobles was secured for its provisions. In return for this
+Eberhard agreed to some limitations on the power of the count,
+and so in a sense founded the constitution of Württemberg.
+At the diet of Worms in 1495 the emperor Maximilian I.
+guaranteed the treaty, confirmed the possessions and prerogatives
+of the house of Württemberg, and raised Eberhard to the rank
+of duke. Eberhard, although a lover of peace, was one of the
+founders of the Swabian League in 1488, and assisted to release
+Maximilian, then king of the Romans, from his imprisonment
+at Bruges in the same year. He gave charters to the towns of
+Stuttgart and Tübingen, and introduced order into the convents
+of his land, some of which he secularized. He took a keen interest
+in the new learning, founded the university of Tübingen in 1476,
+befriended John Reuchlin, whom he made his private secretary,
+welcomed scholars to his court, and is said to have learned Latin
+in later life. In 1482 he again visited Italy and received the
+Golden Rose from Pope Sixtus IV. He won the esteem of the
+emperors Frederick III. and Maximilian I. on account of his
+wisdom and fidelity, and his people held him in high regard.
+His later years were mainly spent at Stuttgart, but he died at
+Tübingen on the 25th of February 1496, and in 1537 his ashes
+were placed in the choir of the Stiftskirche there. Eberhard
+left no children, and the succession passed to his cousin Eberhard,
+who became Duke Eberhard II.</p>
+
+<div class="condensed">
+<p>See Rösslin, <i>Leben Eberhards im Barte</i> (Tübingen, 1793); Bossert,
+<i>Eberhard im Bart</i> (Stuttgart, 1884).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERHARD, CHRISTIAN AUGUST GOTTLOB<a name="ar90" id="ar90"></a></span> (1769-1845),
+German miscellaneous writer, was born at Belzig, near Wittenberg,
+on the 12th of January 1769. He studied theology at
+Leipzig; but, a story he contributed to a periodical having
+proved successful, he devoted himself to literature. With the
+exception of <i>Hannchen und die Küchlein</i> (1822), a narrative
+poem in ten parts, and an epic on the Creation, <i>Der erste Mensch
+und die Erde</i> (1828), Eberhard&rsquo;s work was ephemeral in character
+and is now forgotten. He died at Dresden on the 13th of May
+1845.</p>
+
+<div class="condensed">
+<p>His collected works (<i>Gesammelte Schriften</i>) appeared in 20 volumes
+in 1830-1831.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERHARD, JOHANN AUGUSTUS<a name="ar91" id="ar91"></a></span> (1739-1809), German
+theologian and philosopher, was born at Halberstadt in Lower
+Saxony, where his father was singing-master at the church of
+St Martin&rsquo;s, and teacher of the school of the same name. He
+studied theology at the university of Halle, and became tutor
+to the eldest son of the baron von der Horst, to whose family
+he attached himself for a number of years. In 1763 he was
+appointed con-rector of the school of St Martin&rsquo;s, and second
+preacher in the hospital church of the Holy Ghost; but he soon
+afterwards resigned these offices and followed his patron to
+Berlin. There he met Nicolai and Moses Mendelssohn, with
+whom he formed a close friendship. In 1768 he became preacher
+or chaplain to the workhouse at Berlin and the neighbouring
+fishing village of Stralow. Here he wrote his <i>Neue Apologie des
+Socrates</i> (1772), a work occasioned by an attack on the fifteenth
+chapter of Marmontel&rsquo;s <i>Belisarius</i> made by Peter Hofstede, a
+clergyman of Rotterdam, who maintained the patristic view
+that the virtues of the noblest pagans were only <i>splendida peccata</i>.
+Eberhard stated the arguments for the broader view with
+dignity, acuteness and learning, but the liberality of the reasoning
+gave great offence to the strictly orthodox divines, and is
+believed to have obstructed his preferment in the church.</p>
+
+<p>In 1774 he was appointed to the living of Charlottenburg.
+A second volume of his <i>Apologie</i> appeared in 1778. In this he
+not only endeavoured to obviate some objections which were
+taken to the former part, but continued his inquiries into the
+doctrines of the Christian religion, religious toleration and the
+proper rules for interpreting the Scriptures. In 1778 he accepted
+the professorship of philosophy at Halle. As an academical
+teacher, however, he was unsuccessful. His powers as an original
+thinker were not equal to his learning and his literary gifts, as
+was shown in his opposition to the philosophy of Kant. In 1786
+he was admitted a member of the Berlin Academy of Sciences;
+in 1805 the king of Prussia conferred upon him the honorary title
+of a privy-councillor. In 1808 he obtained the degree of doctor
+in divinity, which was given him as a reward for his theological
+writings. He died on the 6th of January 1809. He was master
+of the learned languages, spoke and wrote French with facility
+and correctness, and understood English, Italian and Dutch.
+He possessed a just and discriminating taste for the fine arts, and
+was a great lover of music.</p>
+
+<div class="condensed">
+<p>Works:&mdash;<i>Neue Apologie des Socrates</i>, &amp;c. (2 vols., 1772-1778);
+<i>Allgemeine Theorie des Denkens und Empfindens</i>, &amp;c. (Berlin, 1776), an
+essay which gained the prize assigned by the Royal Society of Berlin
+for that year; <i>Von dem Begriff der Philosophie und ihren Theilen</i>
+(Berlin, 1778)&mdash;a short essay, in which he announced the plan of his
+lectures on being appointed to the professorship at Halle; <i>Lobschrift
+auf Herrn Johann Thunmann Prof. der Weltweisheit und Beredsamkeit
+auf der Universität zu Halle</i> (Halle, 1779); <i>Amyntor, eine
+Geschichte in Briefen</i> (Berlin, 1782)&mdash;written with the view of
+counteracting the influence of those sceptical and Epicurean principles
+in religion and morals then so prevalent in France, and rapidly
+spreading amongst the higher ranks in Germany; <i>Über die Zeichen
+der Aufklärung einer Nation</i>, &amp;c. (Halle, 1783); <i>Theorie der schönen
+Künste und Wissenschaften</i>, &amp;c. (Halle, 1783, 3rd ed. 1790); <i>Vermischte
+Schriften</i> (Halle, 1784); <i>Neue vermischte Schriften</i> (<i>ib.</i> 1786);
+<i>Allgemeine Geschichte der Philosophie</i>, &amp;c. (Halle, 1788), 2nd ed.
+with a continuation and chronological tables (1796); <i>Versuch einer
+allgemeinen-deutschen Synonymik</i> (Halle and Leipzig, 1795-1802,
+6 vols., 4th ed. 1852-1853), long reckoned the best work on the
+synonyms of the German language (an abridgment of it was published
+by the author in one large volume, Halle, 1802); <i>Handbuch der
+Aesthetik</i> (Halle, 1803-1805, 2nd ed. 1807-1820). He also edited
+the <i>Philosophisches Magazin</i> (1788-1792) and the <i>Philosophisches
+Archiv</i> (1792-1795).</p>
+
+<p>See F. Nicolai, <i>Gedächtnisschrift auf J.A. Eberhard</i> (Berlin and Stettin,
+1810); also K.H. Jördens, <i>Lexicon deutscher Dichter und Prosaisten</i>.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERLIN, JOHANN ERNST<a name="ar92" id="ar92"></a></span> (1702-1762), German musician
+and composer, was born in Bavaria, and became afterwards
+organist in the cathedral at Salzburg, where he died. Most of
+his compositions were for the church (oratorios, &amp;c.), but he also
+wrote some important fugues, sonatas and preludes; and his
+pieces were at one time highly valued by Mozart.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBERS, GEORG MORITZ<a name="ar93" id="ar93"></a></span> (1837-1898), German Egyptologist
+and novelist, was born in Berlin on the 1st of March 1837. At
+Göttingen he studied jurisprudence, and at Berlin oriental
+languages and archaeology. Having made a special study of
+Egyptology, he became in 1865 <i>docent</i> in Egyptian language and
+antiquities at Jena, and in 1870 he was appointed professor in
+these subjects at Leipzig. He had made two scientific journeys
+to Egypt, and his first work of importance, <i>Ägypten und die
+Bücher Moses</i>, appeared in 1867-1868. In 1874 he edited the
+celebrated medical papyrus (&ldquo;Papyrus Ebers&rdquo;) which he had
+discovered in Thebes (translation by H. Joachim, 1890). Ebers
+early conceived the idea of popularizing Egyptian lore by means
+of historical romances. <i>Eine ägyptische Königstochter</i> was
+<span class="pagenum"><a name="page842" id="page842"></a>842</span>
+published in 1864, and obtained great success. His subsequent
+works of the same kind&mdash;<i>Uarda</i> (1877), <i>Homo sum</i> (1878), <i>Die
+Schwestern</i> (1880), <i>Der Kaiser</i> (1881), of which the scene is laid
+in Egypt at the time of Hadrian, <i>Serapis</i> (1885), <i>Die Nilbraut</i>
+(1887), and <i>Kleopatra</i> (1894), were also well received, and did
+much to make the public familiar with the discoveries of Egyptologists.
+Ebers also turned his attention to other fields of
+historical fiction&mdash;especially the 16th century (<i>Die Frau Bürgermeisterin</i>,
+1882; <i>Die Gred</i>, 1887)&mdash;without, however, attaining
+the success of his Egyptian novels. Apart from their antiquarian
+and historical interest, Ebers&rsquo;s books have not a very high literary
+value. His other writings include a descriptive work on Egypt
+(<i>Ägypten in Wort und Bild</i>, 2nd ed., 1880), a guide to Egypt
+(1886) and a life (1885) of his old teacher, the Egyptologist
+Karl Richard Lepsius. The state of his health led him in 1889
+to retire from his chair at Leipzig on a pension. He died at
+Tutzing in Bavaria, on the 7th of August 1898.</p>
+
+<div class="condensed">
+<p>Ebers&rsquo;s <i>Gesammelte Werke</i> appeared in 25 vols. at Stuttgart (1893-1895).
+Many of his books have been translated into English. For
+his life see his <i>Die Geschichte meines Lebens</i> (Stuttgart, 1893); also
+R. Gosche, <i>G. Ebers, der Forscher und Dichter</i> (2nd ed., Leipzig,
+1887).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBERSWALDE<a name="ar94" id="ar94"></a></span>, a town of Germany, in the kingdom of Prussia,
+28 m. N.E. of Berlin by rail; on the Finow canal. Pop. (1905)
+23,876. The town has a Roman Catholic and two Evangelical
+churches, a school of forestry, a gymnasium, a higher-grade girls&rsquo;
+school and two schools of domestic economy. It possesses a
+mineral spring, which attracts numerous summer visitors, and
+has various industries, which include iron-founding and the
+making of horse-shoe nails, roofing material and bricks. A
+considerable trade is carried on in grain, wood and coals. In
+the immediate neighbourhood are one of the chief brass-foundries
+in Germany and an extensive government paper-mill, in which
+the paper for the notes of the imperial bank is manufactured.</p>
+
+<p>Eberswalde received its municipal charter in 1257. It was
+taken and sacked during the Thirty Years&rsquo; War. In 1747
+Frederick the Great brought a colony of Thuringian cutlers to the
+town, but this branch of industry has entirely died out. About
+4 m. to the north lies the old Cistercian monastery of Chorin,
+the fine Gothic church of which contains the tombs of several
+margraves of Brandenburg.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBERT, FRIEDRICH ADOLF<a name="ar95" id="ar95"></a></span> (1791-1834), German bibliographer,
+was born at Taucha, near Leipzig, on the 9th of July
+1791, the son of a Lutheran pastor. At the age of fifteen he was
+appointed to a subordinate post in the municipal library of
+Leipzig. He studied theology for a short time at Leipzig, and
+afterwards philology at Wittenberg, where he graduated doctor in
+philosophy in 1812. While still a student he had already published,
+in 1811, a work on public libraries, and in 1812 another
+work entitled <i>Hierarchiae in religionem ac literas commoda</i>. In
+1813 he was attached to the Leipzig University library, and in
+1814 was appointed secretary to the Royal library of Dresden.
+The same year he published <i>F. Taubmanns Leben und Verdienste</i>,
+and in 1819 <i>Torquato Tasso</i>, a translation from Pierre Louis
+Ginguené with annotations. The rich resources open to him in
+the Dresden library enabled him to undertake the work on which
+his reputation chiefly rests, the <i>Allgemeines bibliographisches
+Lexikon</i>, the first volume of which appeared in 1821 and the second
+in 1830. This was the first work of the kind produced in Germany,
+and the most scientific published anywhere. From 1823 to 1825
+Ebert was librarian to the duke of Brunswick at Wolfenbüttel,
+but returning to Dresden was made, in 1827, chief librarian of
+the Dresden Royal library. Among his other works are&mdash;<i>Die
+Bildung des Bibliothekars</i> (1820), <i>Geschichte und Beschreibung der
+königlichen öffentlichen Bibliothek in Dresden</i> (1822), <i>Zur Handschriftenkunde</i>
+(1825-1827), and <i>Culturperioden des obersächsischen
+Mittelalters</i> (1825). Ebert was a contributor to various
+journals and took part in the editing of Ersch and Gruber&rsquo;s great
+encyclopaedia. He died at Dresden on the 13th of November
+1834, in consequence of a fall from the ladder in his library.</p>
+
+<div class="condensed">
+<p>See the article in <i>Ersch und Grubers Encyclopädie</i>, and that in the
+<i>Allg. deutsche Biog.</i> by his successor in the post of chief librarian in
+Dresden, Schnorr von Carolsfeld.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBINGEN<a name="ar96" id="ar96"></a></span>, a town of Germany, in the kingdom of Württemberg,
+on the Schmiecha, a left-hand tributary of the Danube,
+22 m. S. of Tübingen and 37 m. W. of Ulm by rail. It manufactures
+velvet and cotton-velvet (&ldquo;Manchester&rdquo;) goods, stockings,
+stays, hats, needles, tools, &amp;c. There are also tanneries.
+Pop. 9000.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBIONITES<a name="ar97" id="ar97"></a></span> (Heb. <span title="ebyonim">&#1488;&#1489;&#1497;&#1493;&#1504;&#1501;</span>, &ldquo;poor men&rdquo;), a name given to the
+ultra-Jewish party in the early Christian church. It is first met
+with in Irenaeus (<i>Adv. Haer.</i> i. 26. 2), who sheds no light on the
+origin of the Ebionites, but says that while they admit the world
+to have been made by the true God (in contrast to the Demiurge
+of the Gnostics), they held Cerinthian views on the person of
+Christ, used only the Gospel of Matthew (probably the Gospel
+according to the Hebrews&mdash;so Eusebius), and rejected Paul as an
+apostate from the Mosaic Law, to the customs and ordinances of
+which, including circumcision, they steadily adhered. A similar
+account is given by Hippolytus (<i>Haer.</i> vii. 35), who invents a
+founder named Ebion. Origen (<i>Contra Celsum</i>, v. 61; <i>In Matt.</i>
+tom. xvi. 12) divides the Ebionites into two classes according to
+their acceptance or rejection of the virgin birth of Jesus, but
+says that all alike reject the Pauline epistles. This is confirmed
+by Eusebius, who adds that even those who admitted the virgin
+birth did not accept the pre-existence of Jesus as Logos and
+Sophia. They kept both the Jewish Sabbath and the Christian
+Lord&rsquo;s day, and held extreme millenarian ideas in which Jerusalem
+figured as the centre of the coming Messianic kingdom. Epiphanius
+with his customary confusion makes two separate sects,
+Ebionites and Nazarenes. Both names, however, refer to the
+same people<a name="fa1f" id="fa1f" href="#ft1f"><span class="sp">1</span></a> (the Jewish Christians of Syria), the latter going
+back to the designation of apostolic times (Acts xxiv. 5), and the
+former being the term usually applied to them in the ecclesiastical
+literature of the 2nd and 3rd centuries.</p>
+
+<p>The origin of the Nazarenes or Ebionites as a distinct sect is
+very obscure, but may be dated with much likelihood from the
+edict of Hadrian which in 135 finally scattered the old church of
+Jerusalem. While Christians of the type of Aristo of Pella and
+Hegesippus, on the snapping of the old ties, were gradually
+assimilated to the great church outside, the more conservative
+section became more and more isolated and exclusive. &ldquo;It may
+have been then that they called themselves the Poor Men, probably
+as claiming to be the true representatives of those who had
+been blessed in the Sermon on the Mount, but possibly adding
+to the name other associations.&rdquo; Out of touch with the main
+stream of the church they developed a new kind of pharisaism.
+Doctrinally they stood not so much for a theology as for a refusal
+of theology, and, rejecting the practical liberalism of Paul, became
+the natural heirs of those early Judaizers who had caused the
+apostle so much annoyance and trouble.</p>
+
+<p>Though there is insufficient justification for dividing the
+Ebionites into two separate and distinct communities, labelled
+respectively Ebionites and Nazarenes, we have good evidence,
+not only that there were grades of Christological thought among
+them, but that a considerable section, at the end of the 2nd
+century and the beginning of the 3rd, exchanged their simple
+Judaistic creed for a strange blend of Essenism and Christianity.
+These are known as the Helxaites or Elchasaites, for they accepted
+as a revelation the &ldquo;book of Elchasai,&rdquo; and one Alcibiades of
+Apamea undertook a mission to Rome about 220 to propagate
+its teaching. It was claimed that Christ, as an angel 96 miles
+high, accompanied by the Holy Spirit, as a female angel of the
+same stature, had given the revelation to Elchasai in the 3rd year
+of Trajan (<span class="scs">A.D.</span> 100), but the book was probably quite new in
+Alcibiades&rsquo; time. It taught that Christ was an angel born of
+human parents, and had appeared both before (<i>e.g.</i> in Adam
+and Moses) and after this birth in Judea. His coming did not
+annul the Law, for he was merely a prophet and teacher; Paul
+was wrong and circumcision still necessary. Baptism must be
+repeated as a means of purification from sin, and proof against
+disease; the sinner immerses himself &ldquo;in the name of the mighty
+<span class="pagenum"><a name="page843" id="page843"></a>843</span>
+and most high God,&rdquo; invoking the &ldquo;seven witnesses&rdquo; (sky, water,
+the holy spirits, the angels of prayer, oil, salt and earth), and
+pledging himself to amendment. Abstinence from flesh was
+also enjoined, and a good deal of astrological fancy was interwoven
+with the doctrinal and practical teaching. It is highly
+probable, too, that from these Essene Ebionites there issued the
+fantastical and widely read &ldquo;Clementine&rdquo; literature (<i>Homilies</i>
+and <i>Recognitions</i>) of the 3rd century. Ebionite views lingered
+especially in the country east of the Jordan until they were
+absorbed by Islam in the 7th century.</p>
+
+<div class="condensed">
+<p>In addition to the literature cited see R.C. Ottley, <i>The Doctrine
+of the Incarnation</i>, part iii. § ii.; W. Moeller, <i>Hist. of the Christian
+Church</i>, i. 99; art. in Herzog-Hauck, <i>Realencyklopädie</i>, s.v.
+&ldquo;Ebioniten&rdquo;; also <span class="sc"><a href="#artlinks">Clementine Literature</a></span>.</p>
+</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1f" id="ft1f" href="#fa1f"><span class="fn">1</span></a> So A. Harnack, <i>Hist. of Dogma</i>, i. 301, and F.J.A. Hort, <i>Judaistic
+Christianity</i>, p. 199. Th. Zahn and J.B. Lightfoot (&ldquo;St. Paul and
+the Three,&rdquo; in <i>Commentary on Galatians</i>) maintain the distinction.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBNER-ESCHENBACH, MARIE,<a name="ar98" id="ar98"></a></span> <span class="sc">Freifrau von</span> (1830-&emsp;&emsp;),
+Austrian novelist, was born at Zdislavi&#269; in Moravia, on
+the 13th of September 1830, the daughter of a Count Dubsky.
+She lost her mother in early infancy, but received a careful
+intellectual training from two stepmothers. In 1848 she married
+the Austrian captain, and subsequent field-marshal, Moritz
+von Ebner-Eschenbach, and resided first at Vienna, then at
+Klosterbruck, where her husband had a military charge, and
+after 1860 again at Vienna. The marriage was childless, and
+the talented wife sought consolation in literary work. In her
+endeavours she received assistance and encouragement from
+Franz Grillparzer and Freiherr von Münch-Bellinghausen.
+Her first essay was with the drama <i>Maria Stuart in Schottland</i>,
+which Philipp Eduard Devrient produced at the Karlsruhe
+theatre in 1860. After some other unsuccessful attempts in the
+field of drama, she found her true sphere in narrative. Commencing
+with <i>Die Prinzessin von Banalien</i> (1872), she graphically
+depicts in <i>Bo&#382;ena</i> (Stuttgart, 1876, 4th ed. 1899) and <i>Das
+Gemeindekind</i> (Berlin, 1887, 4th ed. 1900) the surroundings of her
+Moravian home, and in <i>Lotti, die Uhrmacherin</i> (Berlin, 1883, 4th
+ed. 1900), <i>Zwei Comtessen</i> (Berlin, 1885, 5th ed. 1898), <i>Unsühnbar</i>
+(1890, 5th ed. 1900) and <i>Glaubenslos?</i> (1893) the life of the
+Austrian aristocracy in town and country. She also published
+<i>Neue Erzählungen</i> (Berlin, 1881, 3rd ed. 1894), <i>Aphorismen</i>
+(Berlin, 1880, 4th ed. 1895) and <i>Parabeln, Märchen und Gedichte</i>
+(2nd ed., Berlin, 1892). Frau von Ebner-Eschenbach&rsquo;s elegance
+of style, her incisive wit and masterly depiction of character
+give her a foremost place among the German women-writers of
+her time. On the occasion of her seventieth birthday the
+university of Vienna conferred upon her the degree of doctor of
+philosophy, <i>honoris causa</i>.</p>
+
+<div class="condensed">
+<p>An edition of Marie von Ebner-Eschenbach&rsquo;s <i>Gesammelte Schriften</i>
+began to appear in 1893 (Berlin). See A. Bettelheim, <i>Marie von
+Ebner-Eschenbach: biographische Blätter</i> (Berlin, 1900), and M.
+Necker, <i>Marie von Ebner-Eschenbach, nach ihren Werken geschildert</i>
+(Berlin, 1900).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBOLI<a name="ar99" id="ar99"></a></span> (anc. <i>Eburum</i>), a town of Campania, Italy, in the
+province of Salerno, from which it is 16 m. E. by rail, situated
+470 ft. above sea-level, on the S. edge of the hills overlooking
+the valley of the Sele. Pop. (1901) 9642 (town), 12,423 (commune).
+The sacristy of St Francesco contains two 14th-century
+pictures, one by Roberto da Oderisio of Naples. The ancient
+Eburum was a Lucanian city, mentioned only by Pliny and in
+inscriptions, not far distant from the Campanian border. It
+lay above the Via Popillia, which followed the line taken by the
+modern railway. Some scanty remains of its ancient polygonal
+walls may still be seen.</p>
+<div class="author">(T. As.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EBONY<a name="ar100" id="ar100"></a></span> (Gr. <span class="grk" title="ebenos">&#7956;&#946;&#949;&#957;&#959;&#962;</span>), the wood of various species of trees of
+the genus <i>Diospyros</i> (natural order Ebenaceae), widely distributed
+in the tropical parts of the world. The best kinds are very
+heavy, are of a deep black, and consist of heart-wood only.
+On account of its colour, durability, hardness and susceptibility
+of polish, ebony is much used for cabinet work and inlaying,
+and for the manufacture of pianoforte-keys, knife-handles and
+turned articles. The best Indian and Ceylon ebony is furnished
+by <i>D. Ebenum</i>, a native of southern India and Ceylon, which
+grows in great abundance throughout the flat country west of
+Trincomalee. The tree is distinguished from others by the
+inferior width of its trunk, and its jet-black, charred-looking
+bark, beneath which the wood is perfectly white until the heart
+is reached. The wood is stated to excel that obtained from
+<i>D. reticulata</i> of the Mauritius and all other varieties of ebony in
+the fineness and intensity of its dark colour. Although the centre
+of the tree alone is employed, reduced logs 1 to 3 ft. in diameter
+can readily be procured. Much of the East Indian ebony is
+yielded by the species <i>D. Melanoxylon</i> (Coromandel ebony),
+a large tree attaining a height of 60 to 80 ft., and 8 to 10 ft. in
+circumference, with irregular rigid branches, and oblong or
+oblong-lanceolate leaves. The bark of the tree is astringent,
+and mixed with pepper is used in dysentery by the natives of
+India. The wood of <i>D. tomentosa</i>, a native of north Bengal, is
+black, hard and of great weight. <i>D. montana</i>, another Indian
+species, produces a yellowish-grey soft but durable wood.
+<i>D. quaesita</i> is the tree from which is obtained the wood known
+in Ceylon by the name <i>Calamander</i>, derived by Pridham from
+the Sinhalee <i>kalumindrie</i>, black-flowing. Its closeness of grain,
+great hardness and fine hazel-brown colour, mottled and striped
+with black, render it a valuable material for veneering and
+furniture making. <i>D. Dendo</i>, a native of Angola, is a valuable
+timber tree, 25 to 35 ft. high, with a trunk 1 to 2 ft. in diameter.
+The heart-wood is very black and hard and is known as black
+ebony, also as billet-wood, and Gabun, Lagos, Calabar or Niger
+ebony. What is termed Jamaica or West Indian ebony, and
+also the green ebony of commerce, are produced by <i>Brya Ebenus</i>,
+a leguminous tree or shrub, having a trunk rarely more than
+4 in. in diameter, flexible spiny branches, and orange-yellow,
+sweet-scented flowers. The heart-wood is rich dark brown in
+colour, heavier than water, exceedingly hard and capable of
+receiving a high polish.</p>
+
+<p>From the book of Ezekiel (xxvii. 15) we learn that ebony
+was among the articles of merchandise brought to Tyre; and
+Herodotus states (iii. 97) that the Ethiopians every three years
+sent a tribute of 200 logs of it to Persia. Ebony was known
+to Virgil as a product of India (<i>Georg.</i> ii. 116), and was displayed
+by Pompey the Great in his Mithradatic triumph at Rome.
+By the ancients it was esteemed of equal value for durability
+with the cypress and cedar (see Pliny, <i>Nat. Hist.</i> xii. 9, xvi. 79).
+According to Solinus (<i>Polyhistor</i>, cap. lv. p. 353, Paris, 1621),
+it was employed by the kings of India for sceptres and images,
+also, on account of its supposed antagonism to poison, for drinking-cups.
+The hardness and black colour of the wood appear to
+have given rise to the tradition related by Pausanias, and alluded
+to by Southey in <i>Thalaba</i>, i. 22, that the ebony tree produced
+neither leaves nor fruit, and was never seen exposed to the sun.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBRARD, JOHANNES HEINRICH AUGUST<a name="ar101" id="ar101"></a></span> (1818-1888),
+German theologian, was born at Erlangen on the 18th of January
+1818. He was educated in his native town and at Berlin,
+and after teaching in a private family became <i>Privatdocent</i> at
+Erlangen (1841) and then professor of theology at Zürich (1844).
+In 1847 he was appointed professor of theology at Erlangen, a
+chair which he resigned in 1861; in 1875 he became pastor of
+the French reformed church in the same city. As a critic Ebrard
+occupied a very moderate standpoint; as a writer his chief
+works were <i>Christliche Dogmatik</i> (2 vols., 1851), <i>Vorlesungen über
+praktische Theologie</i> (1864), <i>Apologetik</i> (1874-1875, Eng. trans.
+1886). He also edited and completed H. Olshausen&rsquo;s commentary,
+himself writing the volumes on the Epistle to the
+Hebrews, the Johannine Epistles, and Revelation. In the
+department of belles-lettres he wrote a good deal under such
+pseudonyms as Christian Deutsch, Gottfried Flammberg and
+Sigmund Sturm. He died at Erlangen on the 23rd of July 1888.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBRO<a name="ar102" id="ar102"></a></span> (anc. <i>Iberus</i> or <i>Hiberus</i>), the only one of the five great
+rivers of the Iberian Peninsula (Tagus, Douro, Ebro, Guadalquivir,
+Guadiana) which flows into the Mediterranean. The
+Ebro rises at Fuentibre, a hamlet among the Cantabrian Mountains,
+in the province of Santander; at Reinosa, 4 m. east, it is
+joined on the right by the Hijar, and thus gains considerably
+in volume. It flows generally east by south through a tortuous
+valley as far as Miranda de Ebro, passing through the celebrated
+Roman bridge known as La Horadada (&ldquo;the perforated&rdquo;), near
+Oña in Burgos. From Miranda it winds south-eastward through
+<span class="pagenum"><a name="page844" id="page844"></a>844</span>
+the wide basin enclosed on the right by the highlands of Old
+Castile and western Aragon, and on the left by the Pyrenees.
+The chief cities on its banks are Logroño, Calahorra, Tudela,
+Saragossa and Caspe. Near Mora in Catalonia it forces a way
+through the coastal mountains, and, passing Tortosa, falls into
+the Mediterranean about 80 m. south-west of Barcelona, after
+forming by its delta a conspicuous projection on the otherwise
+regular coast line. In its length, approximately 465 m., the Ebro
+is inferior to the Tagus, Guadiana and Douro; it drains an area
+of nearly 32,000 sq. m. Its principal tributaries are&mdash;from the
+right hand the Jalon with its affluent the Jiloca, the Huerva,
+Aguas, Martin, Guadalope and Matarraña; from the left the
+Ega, Aragon, Arba, Gallego, and the Segre with its intricate
+system of confluent rivers. The Ebro and its tributaries have
+been utilized for irrigation since the Moorish conquest; the
+main stream becomes navigable by small boats about Tudela;
+but its value as a means of communication is almost neutralized
+by the obstacles in its channel, and seafaring vessels cannot
+proceed farther up than Tortosa. The great Imperial Canal,
+begun under the emperor Charles V. (1500-1558), proceeds along
+the right bank of the river from a point about 3 m. below Tudela,
+to El Burgo de Ebro, 5 m. below Saragossa; the irrigation canal
+of Tauste skirts the opposite bank for a shorter distance; and the
+San Carlos or New Canal affords direct communication between
+Amposta at the head of the delta and the harbour of Los
+Alfaques. From Miranda to Mora the Bilbao-Tarragona railway
+follows the course of the Ebro along the right bank.</p>
+
+
+<hr class="art" />
+<p><span class="bold">EBROÏN<a name="ar103" id="ar103"></a></span> (d. 681), Frankish &ldquo;mayor of the palace,&rdquo; was a
+Neustrian, and wished to impose the authority of Neustria over
+Burgundy and Austrasia. In 656, at the moment of his accession
+to power, Sigebert III., the king of Austrasia, had just died, and
+the Austrasian mayor of the palace, Grimoald, was attempting
+to usurp the authority. The great nobles, however, appealed to
+the king of Neustria, Clovis II., and unity was re-established.
+But in spite of a very firm policy Ebroïn was unable to maintain
+this unity, and while Clotaire III., son of Clovis II., reigned in
+Neustria and Burgundy, he was obliged in 660 to give the
+Austrasians a special king, Childeric II., brother of Clotaire III.,
+and a special mayor of the palace, Wulfoald. He endeavoured
+to maintain at any rate the union of Neustria and Burgundy,
+but the great Burgundian nobles wished to remain independent,
+and rose under St Leger (Leodegar), bishop of Autun, defeated
+Ebroïn, and interned him in the monastery of Luxeuil (670).
+A proclamation was then issued to the effect that each kingdom
+should keep its own laws and customs, that there should be no
+further interchange of functionaries between the kingdoms, and
+that no one should again set up a tyranny like that of Ebroïn.
+Soon, however, Leger was defeated by Wulfoald and the Austrasians,
+and was himself confined at Luxeuil in 673. In the same
+year, taking advantage of the general anarchy, Ebroïn and Leger
+left the cloister and soon found themselves once more face to face.
+Each looked for support to a different Merovingian king, Ebroïn
+even proclaiming a false Merovingian as sovereign. In this
+struggle Leger was vanquished; he was besieged in Autun, was
+forced to surrender and had his eyes put out, and, on the 12th
+of October 678, he was put to death after undergoing prolonged
+tortures. The church honours him as a saint. After his death
+Ebroïn became sole and absolute ruler of the Franks, imposing
+his authority over Burgundy and subduing the Austrasians,
+whom he defeated in 678 at Bois-du-Fay, near Laon. His
+triumph, however, was short-lived; he was assassinated in 681,
+the victim of a combined attack of his numerous enemies. He
+was a man of great energy, but all his actions seem to have been
+dictated by no higher motives than ambition and lust of power.</p>
+
+<div class="condensed">
+<p>See <i>Liber historiae Francorum</i>, edited by B. Krusch, in <i>Mon.
+Germ. hist. script. rer. Merov.</i> vol. ii.; <i>Vita sancti Leodegarii</i>, by
+Ursinus, a monk of St Maixent (Migne, <i>Patr. Latina</i>, vol. xcvi.);
+&ldquo;Vita metrica&rdquo; in <i>Poetae Latini aevi Carolini</i>, vol. iii. (<i>Mon. Germ.
+hist.</i>); J.B. Pitra, <i>Histoire de Saint Léger</i> (Paris, 1846); and
+J. Friedrich, &ldquo;Zur Gesch. des Hausmeiers Ebroïn,&rdquo; in the <i>Proceedings
+of the Academy of Munich</i> (1887, pp. 42-61).</p>
+</div>
+<div class="author">(C. Pf.)</div>
+
+<hr class="art" />
+<p><span class="bold">EBUR&#256;CUM,<a name="ar104" id="ar104"></a></span> or <span class="sc">Ebor&#257;cum</span> (probably a later variant), the
+Roman name of York (<i>q.v.</i>) in England. Established about <span class="scs">A.D.</span>
+75-80 as fortress of the Ninth legion and garrisoned (after the annihilation
+of that legion about <span class="scs">A.D.</span> 118) by the Sixth legion, it developed
+outside its walls a town of civil life, which later obtained
+Roman municipal rank and in the 4th century was the seat of a
+Christian bishop. The fortress and town were separated by the
+Ouse. On the left bank, where the minster stands, was the fortress,
+of which the walls can still be partly traced, and one corner
+(the so-called Multangular Tower) survives. The municipality
+occupied the right bank near the present railway station. The
+place was important for its garrison and as an administrative
+centre, and the town itself was prosperous, though probably
+never very large. The name is preserved in the abbreviated
+form Ebor in the official name of the archbishop of York, but the
+philological connexion between Eboracum and the modern name
+York is doubtful and has probably been complicated by Danish
+influence.</p>
+<div class="author">(F. J. H.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">EÇA DE QUEIROZ, JOSÉ MARIA<a name="ar105" id="ar105"></a></span> (1843-1900), Portuguese
+writer, was born at the northern fishing town of Povoa de
+Varzim, his father being a retired judge. He went through the
+university of Coimbra, and on taking his degree in law was
+appointed Administrador de Concelho at Leiria, but soon tired
+of the narrow mental atmosphere of the old cathedral town and
+left it. He accompanied the Conde de Rezende to Egypt, where
+he assisted at the opening of the Suez Canal, and to Palestine,
+and on his return settled down to journalism in Lisbon and began
+to evolve a style, at once magical and unique, which was to
+renovate his country&rsquo;s prose. Though he spent much of his
+days with the philosopher sonneteer Anthero de Quental, and
+the critic Jayme Batalha Reis, afterwards consul-general in
+London, he did not restrict his intimacy to men of letters, but
+frequented all kinds of society, acquiring a complete acquaintance
+with contemporary Portuguese life and manners. Entering
+the consular service in 1872, he went to Havana, and, after a tour
+in the United States, was transferred two years later to Newcastle-on-Tyne
+and in 1876 to Bristol. In 1888 he became Portuguese
+consul-general in Paris, and there died in 1900.</p>
+
+<p>Queiroz made his literary début in 1870 by a sensational story,
+<i>The Mystery of the Cintra Road</i>, written in collaboration with the
+art critic Ramalho Ortigão, but the first publication which
+brought him fame was <i>The Farpas</i>, a series of satirical and
+humorous sketches of various phases of social life, which, to quote
+the poet Guerra Junqueiro, contain &ldquo;the epilepsy of talent.&rdquo;
+These essays, the joint production of the same partners, criticized
+and ridiculed the faults and foibles of every class in turn, mainly
+by a comparison with the French, for the education of Queiroz
+had made him a Frenchman in ideas and sympathies. His
+Brazilian friend, Eduardo Prado, bears witness that at this
+period French literature, especially Hugo&rsquo;s verse, and even
+French politics, interested Queiroz profoundly, while he altogether
+ignored the <i>belles-lettres</i> of his own country and its public
+affairs. This phase lasted for some years, and even when he
+travelled in the East he was inclined to see it with the eyes of
+Flaubert, though the publication of <i>The Relic</i> and that delightful
+prose poem <i>Sweet Miracle</i> afterwards showed that he had been
+directly impressed and deeply penetrated by its scenery, poetry
+and mysticism. The Franco-German War of 1870, however, by
+lowering the prestige of France, proved the herald of a national
+Portuguese revival, and had a great influence on Queiroz, as
+also had his friend Oliveira Martins (<i>q.v.</i>), the biographer of the
+patriot kings of the Aviz dynasty. He founded the Portuguese
+Realist-Naturalist school, of which he remained for the rest of
+his life the chief exponent, by a powerful romance, <i>The Crime
+of Father Amaro</i>, written in 1871 at Leiria but only issued in 1875.
+Its appearance then led to a baseless charge that he had
+plagiarized <i>La Faute de l&rsquo;Abbé Mouret</i>, and ill-informed critics
+began to name Queiroz the Portuguese Zola, though he clearly
+occupied an altogether different plane in the domain of art.
+During his stay in England he produced two masterpieces,
+<i>Cousin Basil</i> and <i>The Maias</i>, but they show no traces of English
+influence, nor again are they French in tone, for, living near to
+France, his disillusionment progressed and was completed when
+he went to Paris and had to live under the régime of the Third
+<span class="pagenum"><a name="page845" id="page845"></a>845</span>
+Republic. Settling at Neuilly, the novelist became chronicler,
+critic, and letter-writer as well, and in all these capacities
+Queiroz displayed a spontaneity, power and artistic finish
+unequalled in the literature of his country since the death of
+Garrett. A bold draughtsman, he excelled in freshness of
+imagination and careful choice and collocation of words, while
+his warmth of colouring and brilliance of language speak of the
+south. Many of his pages descriptive of natural scenery, such
+for instance as the episode of the return to Tormes in <i>The City
+and the Mountains</i>, have taken rank as classic examples of
+Portuguese prose, while as a creator of characters he stood
+unsurpassed by any writer of his generation in the same field.
+He particularly loved to draw and judge the middle class, and
+he mocks at and chastises its hypocrisy and narrowness, its
+veneer of religion and culture, its triumphant lying, its self-satisfied
+propriety, its cruel egotism. But though he manifested
+a predilection for middle-class types, his portrait gallery comprises
+men and women of all social conditions. <i>The Maias</i>,
+his longest book, treats of <i>fidalgos</i>, while perhaps his most remarkable
+character study is of a servant, Juliana, in <i>Cousin Basil</i>.
+At least two of his books, this latter and <i>The Crime of Father
+Amaro</i>, are <i>chroniques scandaleuses</i> in their plots and episodes;
+these volumes, however, mark not only the high-water line of the
+Realist-Naturalist school in Portugal, but are in themselves, leaving
+aside all accidentals, creative achievements of a high order.</p>
+
+<p>Though Queiroz was a keen satirist of the ills of society, his
+pages show hardly a trace of pessimism. <i>The City and the
+Mountains</i>, and in part <i>The Relic</i> also, reveal the apostle of
+Realism as an idealist and dreamer, a true representative of
+that Celtic tradition which survives in the race and has permeated
+the whole literature of Portugal. <i>The Mandarin</i>, a fantastic
+variation on the old theme of a man self-sold to Satan, and <i>The
+Illustrious House of Ramires</i>, are the only other writings of his
+that require mention, except <i>The Correspondence of Fradique
+Mendes</i>. In conjunction with Anthero de Quental and Jayme
+Batalha Reis, Queiroz invented under that name a smart man
+of the world who had something of himself and something of
+Eduardo Prado, and made him correspond on all sorts of subjects
+with imaginary friends and relatives to the delight of the public,
+many of whom saw in him a mysterious new writer whose identity
+they were eager to discover. These sparkling and humorous
+letters are an especial favourite with admirers of Queiroz, because
+they reveal so much of his very attractive personality, and
+perhaps the cleverest of the number, that on Pacheco, has
+received an English dress. In addition to his longer and more
+important works, Queiroz wrote a number of short stories,
+some of which have been printed in a volume under the title of
+<i>Contos</i>. The gems of this remarkable collection are perhaps
+<i>The Peculiarities of a Fair-haired Girl</i>, <i>A Lyric Poet</i>, <i>José
+Matthias</i>, <i>The Corpse</i>, and <i>Sweet Miracle</i>.</p>
+
+<div class="condensed">
+<p>Most of his books have gone through many editions, and they are
+even more appreciated in the Brazils than in Portugal. It should be
+mentioned that the fourth edition of <i>Father Amaro</i> is entirely different
+in form and action from the first, the whole story having been rewritten.
+One of Queiroz&rsquo;s romances and two of his short stories
+have been published in English. An unsatisfactory version of
+<i>Cousin Basil</i>, under the title <i>Dragon&rsquo;s Teeth</i>, appeared at Boston,
+U.S.A., in 1889, while <i>Sweet Miracle</i> has had three editions in England
+and one in America, and there is also a translation of <i>O Defunto</i> (<i>The
+Corpse</i>) under the name of <i>Our Lady of the Pillar</i>.</p>
+
+<p>An admirable critical study of the work of Queiroz will be found
+in <i>A Geração Nova&mdash;Os Novellistas</i>, by J. Pereira de Sampaio (<i>Bruno</i>),
+(Oporto, 1886). The <i>Revista moderna</i> of the 20th of November 1897
+was entirely devoted to him. Senhor Batalha Reis gives interesting
+reminiscences of the novelist&rsquo;s early days in his preface to some
+prose fragments edited by him and named <i>Prosas Barbaras</i> (Oporto,
+1903).</p>
+</div>
+<div class="author">(E. Pr.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ÉCARTÉ<a name="ar106" id="ar106"></a></span> (Fr. for &ldquo;separated,&rdquo; &ldquo;discarded&rdquo;), a game at
+cards, of modern origin, probably first played in the Paris <i>salons</i>
+in the first quarter of the 19th century. It is a development of
+a very old card game called <i>la triomphe</i> or <i>French-ruff</i>. Écarté
+is generally played by two persons, but a pool of three may be
+formed, the player who is out taking the place of the loser, and
+the winner of two consecutive games winning the pool. At
+French écarté (but not at English) bystanders who are betting
+may advise the players, but only by pointing to the cards they
+desire them to play, and the loser of the game goes out, one of
+the <i>rentrants</i> taking his place, unless the loser is playing <i>la
+chouette</i>, <i>i.e.</i> playing single-handed against two, and taking
+all bets.</p>
+
+<p>The small cards (from the two to the six, both inclusive) are
+removed from an ordinary pack. The players cut for deal, the
+highest having the choice. The king is the highest card, the ace
+ranking after the knave. The dealer gives five cards to his
+adversary, and five to himself, by two at a time to each and by
+three at a time to each, or vice versa. The eleventh card is
+turned up for trumps. If it is a king, the dealer scores one, at
+any time before the next deal. The non-dealer then looks at
+his cards. If satisfied with them he plays, and there is no discarding;
+if not satisfied he &ldquo;proposes.&rdquo; The dealer may either
+accept or refuse. If he accepts, each player discards face downwards
+as many cards as he thinks fit, and fresh ones are given
+from the undealt cards or &ldquo;stock,&rdquo; first to complete the non-dealer&rsquo;s
+hand to five, then to complete the dealer&rsquo;s. To ask for
+&ldquo;a book&rdquo; is to ask for five cards. Similarly a second proposal
+may be made, and so on, until one player is satisfied with his
+hand. If the dealer refuses, the hand is played without discarding.
+If the non-dealer announces that he holds the king
+of trumps, he scores one; and similarly, if the dealer holds the
+king and announces it, he scores one. The announcement
+must be made before playing one&rsquo;s first card, or if that card be
+the king, on playing it. The non-dealer, being satisfied with
+his hand, leads a card. The dealer plays a card to it, the two
+cards thus played forming a trick. The winner of the trick leads
+to the next, and so on. The second to play to a trick must follow
+suit if able, and must win the trick if he can.</p>
+
+<p>The scores are for the king and for the majority of tricks.
+The player who wins three tricks scores one for the &ldquo;point&rdquo;;
+if he wins all five tricks, he scores two for the &ldquo;vole.&rdquo; If the
+non-dealer plays without proposing, or the dealer refuses the
+first proposal, and fails to win three tricks, the adversary scores
+two, but no more even if he wins the vole. The game is five up.
+The points are conveniently marked with a three-card and a
+two-card, as at euchre. The three is put face upwards with the
+two face downwards on the top of it. When one or two or three
+points are scored the top card is moved so as to expose them.
+At four, one pip of the two-card is put under the other card.
+Games may be recorded similarly.</p>
+
+<div class="condensed">
+<p><i>Hints to Players.</i>&mdash;The following hints may be of service to beginners:&mdash;</p>
+
+<p>Shuffle thoroughly after every deal.</p>
+
+<p>Do not announce the king until in the act of playing your first
+card.</p>
+
+<p>The hands which should be played without proposing, called
+<i>jeux de règle</i> (standard hands), ought to be thoroughly known. They
+are as follows:&mdash;</p>
+
+<p>1. All hands with three or more trumps, whatever the other cards.</p>
+
+<p>2. Hands with <i>two trumps</i> which contain also&mdash;</p>
+
+<div class="list">
+<p>(<i>a</i>) Any three cards of one plain suit;</p>
+
+<p>(<i>b</i>) Two cards of one plain suit, one being as high as a queen;</p>
+
+<p>(<i>c</i>) Two small cards of one suit, the fifth card being a king
+of another suit;</p>
+
+<p>(<i>d</i>) Three high cards of different suits.</p>
+</div>
+
+<p>3. Hands with <i>one trump</i>, which contain also&mdash;</p>
+
+<div class="list">
+<p>(<i>a</i>) King, queen, knave of one suit, and a small card of another;</p>
+
+<p>(<i>b</i>) Four cards of one suit headed by king;</p>
+
+<p>(<i>c</i>) Three cards of one suit headed by queen, and queen of
+another suit.</p>
+</div>
+
+<p>4. Hands with <i>no trump</i>, which contain three queens or cards of
+equal value in different suits, <i>e.g.</i>, four court cards.</p>
+
+<p>5. Hands from which only two cards can be discarded without
+throwing a king or a trump.</p>
+
+<p>Holding cards which make the point certain, propose. If you
+hold a <i>jeu de règle</i>, and one of the trumps is the king, propose, as
+your adversary cannot then take in the king.</p>
+
+<p>When discarding, throw out all cards except trumps and kings.</p>
+
+<p>If your adversary proposes you should accept, unless you are
+guarded in three suits (a queen being a sufficient guard), or in two
+suits with a trump, or in one suit with two trumps. Hence the
+rule not to discard two cards, unless holding the king of trumps,
+applies to the dealer.</p>
+
+<p>The hands with which to refuse are the same as those with which
+to play without proposing, except as follows:&mdash;</p>
+
+<p><span class="pagenum"><a name="page846" id="page846"></a>846</span></p>
+
+<p>1. Two trumps and three cards of one plain suit should not be
+played unless the plain suit is headed by a court card.</p>
+
+<p>2. One trump and a tierce major is too weak, unless the fifth
+card is a court card. With similar hands weaker in the tierce major
+suit, accept unless the fifth card is a queen.</p>
+
+<p>3. One trump and four cards of a plain suit is too weak to play.</p>
+
+<p>4. One trump and two queens is too weak, unless both queens are
+singly guarded.</p>
+
+<p>5. One trump, queen of one suit, and knave guarded of another
+should not be played unless the queen is also guarded, or the card
+of the fourth suit is a court card.</p>
+
+<p>6. One trump, a king and a queen, both unguarded, should not
+be played, unless the fourth suit contains a card as high as an ace.</p>
+
+<p>7. Four court cards without a trump are too weak to play, unless
+they are of three different suits.</p>
+
+<p>Refuse with three queens, if two are singly guarded; otherwise,
+accept.</p>
+
+<p>Lead from your guarded suit, and lead the highest.</p>
+
+<p>If the strong suit led is not trumped, persevere with it, unless with
+king of trumps, or queen (king not having been announced), or knave
+ace, when lead a trump before continuing your suit.</p>
+
+<p>You should not lead trumps at starting, unless you hold king or
+queen, knave, or knave ace, with court cards out of trumps.</p>
+
+<p>The score has to be considered. If the dealer is at four, and the
+king is not in your hand nor turned up, play any cards without
+proposing which give an even chance of three tricks, <i>e.g.</i> a queen,
+a guarded knave, and a guarded ten. The same rule applies to the
+dealer&rsquo;s refusal.</p>
+
+<p>At the adverse score of four, and king not being in hand or turned
+up, any hand with one trump should be played, unless the plain
+cards are very small and of different suits.</p>
+
+<p>If the non-dealer plays without proposing when he is four to
+three, and the dealer holds the king he ought not to mark it. The
+same rule applies to the non-dealer after a refusal, if the dealer is
+four to three.</p>
+
+<p>At the score of non-dealer three, dealer four, the dealer should
+refuse on moderate cards, as the player proposing at this score must
+have a very bad hand.</p>
+
+<p>At four a forward game should not be played in trumps, as there
+is no advantage in winning the vole.</p>
+
+<p><i>Laws of Écarté.</i>&mdash;The following laws are abridged from the revised
+code adopted by the Turf Club:&mdash;A cut must consist of at least two
+cards. Card exposed in cutting, fresh cut. Order of distribution of
+cards, whether by three and two, or vice versa, once selected, dealer
+must not change it during game. Player announcing king when he
+has not got it, and playing a card without declaring error, adversary
+may correct score and have hand played over again. If offender
+wins point or vole that hand, he scores one less than he wins. Proposal,
+acceptance, or refusal made cannot be retracted. Cards discarded
+must not be looked at. Cards exposed in giving cards to
+non-dealer, he has option of taking them or of having next cards;
+dealer exposing his own cards, no penalty. Dealer turning up top
+card after giving cards, cannot refuse second discard. Dealer
+accepting when too few cards in stock to supply both, non-dealer
+may take cards, and dealer must play his hand. Card led in turn
+cannot be taken up again. Card played to a lead can only be taken
+up prior to another lead, to save revoke or to correct error of not
+winning trick. Card led out of turn may be taken up prior to its
+being played to. Player naming one suit and leading another,
+adversary has option of requiring suit named to be led. If offender
+has none, no penalty. Player abandoning hand, adversary is deemed
+to win remaining tricks, and scores accordingly. If a player revokes
+or does not win trick when he can do so, the adversary may correct
+score and have hand replayed.</p>
+
+<p>See <i>Académie des jeux</i> (various editions after the first quarter of
+the 19th century); Hoyle&rsquo;s <i>Games</i> (various editions about the same
+dates); Ch. Van-Tenac et Louis Delanoue, <i>Traité du jeu de l&rsquo;écarté</i>
+(Paris, 1845; translated in Bohn&rsquo;s <i>Handbook of Games</i>, London,
+1850); &ldquo;Cavendish,&rdquo; <i>The Laws of Écarté, adopted by the Turf Club,
+with a Treatise on the Game</i> (London, 1878); <i>Pocket Guide to Écarté</i>
+(&ldquo;Cavendish,&rdquo; 1897); Foster&rsquo;s <i>Encyclopaedia of Indoor Games</i>
+(1903).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECBATANA<a name="ar107" id="ar107"></a></span> (<i>Agbatana</i> in Aeschylus, <i>Ha&#328;gmat&#257;na</i> in Old
+Persian, written <i>Agamtanu</i> by Nabonidos, and <i>Agamatanu</i> at
+Behistun, mod. <i>Hamad&#257;n</i>), the capital of Astyages (Istuvegu),
+which was taken by Cyrus in the sixth year of Nabonidos
+(549 <span class="scs">B.C.</span>). The Greeks supposed it to be the capital of Media,
+confusing the Manda, of whom Astyages was king, with the Mad&#257;
+or Medes of Media Atropatene, and ascribed its foundation to
+Deioces (the <i>Daiukku</i> of the cuneiform inscriptions), who is said
+to have surrounded his palace in it with seven concentric walls of
+different colours. Under the Persian kings, Ecbatana, situated
+at the foot of Mount Elvend, became a summer residence; and
+was afterwards the capital of the Parthian kings. Sir H.
+Rawlinson attempted to prove that there was a second and older
+Ecbatana in Media Atropatene, on the site of the modern Takht-i-Suleiman,
+midway between Hamadan and Tabriz (<i>J.R.G.S.</i>
+x. 1841), but the cuneiform texts imply that there was only one
+city of the name, and Takht-i-Suleiman is the Gazaca of classical
+geography. The Ecbatana at which Cambyses is said by
+Herodotus (iii. 64) to have died is probably a blunder for Hamath.</p>
+
+<div class="condensed">
+<p>See Perrot and Chipiez, <i>History of Art in Persia</i> (Eng. trans., 1892);
+M. Dieulafoy, <i>L&rsquo;Art antique de la Perse</i>, pt. i. (1884); J. de Morgan,
+<i>Mission scientifique en Perse</i>, ii. (1894). See <span class="sc"><a href="#artlinks">Hamadan</a></span> and <span class="sc"><a href="#artlinks">Persia</a></span>:
+<i>Ancient History</i>, § v. 2.</p>
+</div>
+<div class="author">(A. H. S.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCARD, JOHANN<a name="ar108" id="ar108"></a></span> (1553-1611), German composer of church
+music, was born at Mühlhausen on the Unstrut, Prussia, in 1553.
+At the age of eighteen he went to Munich, where he became the
+pupil of Orlando Lasso. In his company Eccard is said to have
+visited Paris, but in 1574 we find him again at Mühlhausen,
+where he resided for four years, and edited, together with Johann
+von Burgk, his first master, a collection of sacred songs, called
+<i>Crepundia sacra Helmboldi</i> (1577). Soon afterwards he obtained
+an appointment as musician in the house of Jacob Fugger, the
+Augsburg banker. In 1583 he became assistant conductor, and
+in 1599 conductor, at Königsberg, to Georg Friedrich, margrave
+of Brandenburg-Anspach, the administrator of Prussia. In 1608
+he was called by the elector Joachim Friedrich to Berlin as chief
+conductor, but this post he held only for three years, owing to
+his premature death at Königsberg in 1611. Eccard&rsquo;s works
+consist exclusively of vocal compositions, such as songs, sacred
+cantatas and chorales for four or five, and sometimes for seven,
+eight, or even nine voices. Their polyphonic structure is a
+marvel of art, and still excites the admiration of musicians. At
+the same time his works are instinct with a spirit of true religious
+feeling. His setting of the beautiful words &ldquo;Ein&rsquo; feste Burg ist
+unser Gott&rdquo; is still regarded by the Germans as their representative
+national hymn. Eccard and his school are inseparably connected
+with the history of the Reformation.</p>
+
+<div class="condensed">
+<p>Of Eccard&rsquo;s songs a great many collections are extant; see
+K.G.A. von Winterfeld, <i>Der Evangelische Kirchengesang</i> (1843);
+Döring (<i>Choralkunde</i>, p. 47).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCELINO<a name="ar109" id="ar109"></a></span> [or <span class="sc">Ezzelino</span>] <b>DA ROMANO</b> (1194-1259), Ghibelline
+leader, and supporter of the emperor Frederick II., was born on
+the 25th of April 1194. He belonged to a family descended from
+a German knight named Eccelin, who followed the emperor
+Conrad II. to Italy about 1036, and received the fief of Romano
+near Padua. Eccelin&rsquo;s grandson was Eccelino III., surnamed
+the Monk, who divided his lands between his two sons in 1223,
+and died in 1235. The elder of these two sons was Eccelino,
+who in early life began to take part in family and other feuds,
+and in 1226, at the head of a band of Ghibellines, seized Verona
+and became <i>podestà</i> of the city. He soon lost Verona, but regained
+it in 1230; and about this time came into relations with
+Frederick II., who in 1232 issued a charter confirming him in his
+possessions. In 1236 when besieged in Verona he was saved by
+the advance of the emperor, who in November of the same year
+took Vicenza and entrusted its government to Eccelino. In
+1237 he obtained authority over Padua and Treviso; and on the
+27th of November in that year he shared in the victory gained
+by the emperor over the Lombards at Cortenuova. In 1238 he
+married Frederick&rsquo;s natural daughter, Selvaggia; in 1239 was
+appointed imperial vicar of the march of Treviso; but in the
+same year was excommunicated by Pope Gregory IX. He was
+constantly engaged in increasing his possessions; was present
+at the siege of Parma in 1247, and after Frederick&rsquo;s death in
+1250 he supported his son, the German king Conrad IV. His
+cruelties had, however, aroused general disgust, and in 1254 he
+was again excommunicated. In 1256 Pope Alexander IV.
+proclaimed a crusade against him, and a powerful league was
+soon formed under the leadership of Philip, archbishop of
+Ravenna. Padua was taken from Eccelino, but on the 1st of
+September 1258 he defeated his enemies at Torricella. He then
+made an attempt on Milan, and the rival forces met at Cassano
+on the 27th of September 1259, when Eccelino was wounded and
+taken prisoner. Enraged at his capture, he tore the bandages
+from his wounds, refused to take nourishment, and died at
+Soncino on the 7th of October 1259. In the following year his
+brother Albert was put to death, and the Romano family became
+<span class="pagenum"><a name="page847" id="page847"></a>847</span>
+extinct. Eccelino, who is sometimes called the <i>tyrant</i>, acquired
+a terrible reputation on account of his cruelties, a reputation
+that won for him the immortality of inclusion in Dante&rsquo;s <i>Inferno</i>;
+but his unswerving loyalty to Frederick II. forms a marked
+contrast to the attitude of many of his contemporaries.</p>
+
+<p>Eccelino is the subject of a novel by Cesare Cantu and of a
+drama by J. Eichendorff.</p>
+
+<div class="condensed">
+<p>See J.M. Gittermann, <i>Ezzelino da Romano</i> (Freiburg, 1890);
+S. Mitis, <i>Storia d&rsquo; Ezzelino IV. da Romano</i> (Maddaloni, 1896); and
+F. Stieve, <i>Ezzelino von Romano</i> (Leipzig, 1909).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCENTRIC<a name="ar110" id="ar110"></a></span> (from Gr. <span class="grk" title="ek">&#7952;&#954;</span>, out of, and <span class="grk" title="kentron">&#954;&#941;&#957;&#964;&#961;&#959;&#957;</span>, centre), literally
+&ldquo;out from the centre,&rdquo; and thus used to connote generally any
+deviation from the normal. In astronomy the word denotes a
+circle round which a body revolves, but whose centre is displaced
+from the visible centre of motion. In the ancient astronomy the
+ellipses in which it is now known that the planets revolve around
+the sun could not be distinguished from circles, but the unequal
+angular motion due to ellipticity was observed. The theory of
+the eccentric was that the centre of the epicycle of each planet
+moved uniformly in a circle, the centre of which was displaced
+from that of the earth by an amount double the eccentricity of
+the actual ellipse, as the case is now understood. When measured
+around this imaginary centre, which is so situated on the major
+axis of the ellipse that the focus, or place of the real sun, is
+midway between it and the centre of the ellipse, the motion is
+approximately uniform. In engineering, an eccentric is a
+mechanical device for converting rotary into reciprocating
+motion (see <span class="sc"><a href="#artlinks">Steam-engine</a></span>). For eccentric angle see <span class="sc"><a href="#artlinks">Ellipse</a></span>.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECCHELLENSIS<a name="ar111" id="ar111"></a></span> (or <span class="sc">Echellensis</span>), <b>ABRAHAM</b> (d. 1664), a
+learned Maronite, whose surname is derived from Eckel in Syria,
+where he was born towards the close of the 16th century. He
+was educated at the Maronite college in Rome, and, after taking
+his doctor&rsquo;s degree in theology and philosophy, returned for a
+time to his native land. He then became professor of Arabic
+and Syriac in the college of the Propaganda at Rome. Called to
+Paris in 1640 to assist Le Jay in the preparation of his polyglot
+Bible, he contributed to that work the Arabic and Latin versions
+of the book of Ruth and the Arabic version of the third book of
+Maccabees. In 1646 he was appointed professor of Syriac and
+Arabic at the Collège de France. Being invited by the Congregation
+of the Propaganda to take part in the preparation of an
+Arabic version of the Bible, Ecchellensis went again in 1652 or
+1653 to Rome. He published several Latin translations of Arabic
+works, of which the most important was the <i>Chronicon Orientale</i>
+of Ibnar-R&#257;hib (Paris, 1653), a history of the patriarchs of
+Alexandria. He was engaged in an interesting controversy with
+John Selden as to the historical grounds of episcopacy, in the
+course of which he published his <i>Eutychius vindicatus, sive
+Responsio ad Seldeni Origines</i> (Rome, 1661). Conjointly with
+Giovanni Borelli he wrote a Latin translation of the 5th, 6th
+and 7th books of the <i>Conics</i> of Apollonius of Perga (1661). He
+died at Rome in 1664.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLES,<a name="ar112" id="ar112"></a></span> a municipal borough in the Eccles parliamentary
+division of Lancashire, England, 4 m. W. of Manchester, of which
+it forms practically a suburb. Pop. (1901) 34,369. It is served
+by the London &amp; North-Western railway and by the Birkenhead
+railway (North-Western and Great Western joint). The Manchester
+Ship Canal passes through. The church of St Mary is
+believed to date from the 12th century, but has been enlarged
+and wholly restored in modern times. There are several handsome
+modern churches and chapels, a town hall, and numerous
+cotton mills, while silk-throwing and the manufacture of fustians
+and ginghams are also among the industries, and there are also
+large engine works. A peculiar form of cake is made here,
+taking name from the town, and has a wide reputation. Eccles
+was incorporated in 1892, and the corporation consists of a mayor,
+6 aldermen and 18 councillors. The borough maintains the
+tramway service, &amp;c., but water and gas are supplied from
+Manchester and Salford respectively. Area, 2057 acres.</p>
+
+<p>Before the Reformation the monks of Whalley Abbey had a
+grange here at what is still called Monks&rsquo; Hall; and in 1864
+many thousands of silver pennies of Henry III. and John of
+England and William I. of Scotland were discovered near the
+spot. Robert Ainsworth, the author of the Latin and English
+dictionary so long familiar to English students, was born at Eccles
+in 1660; and it was at the vicarage that William Huskisson
+expired on the 15th of September 1830 from injuries received at
+the opening of the Liverpool &amp; Manchester railway. From early
+times &ldquo;wakes&rdquo; were held at Eccles, and bull-baiting, bear-baiting
+and cock-fighting were carried on. Under Elizabeth
+these festivals, which had become notoriously disorderly, were
+abolished, but were revived under James I., and maintained
+until late in the 19th century on public ground. The cockpit
+remained on the site of the present town hall. A celebration
+on private property still recalls these wakes.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESFIELD,<a name="ar113" id="ar113"></a></span> a township in the Hallamshire parliamentary
+division of the West Riding of Yorkshire, England, 5 m. N. of
+Sheffield, on the Great Central and Midland railways. The
+church of St Mary is Perpendicular, with a central tower, and contains
+excellent woodwork. It formerly bore, and must have
+deserved, the familiar title of the &ldquo;Minster of the Moors.&rdquo;
+Ecclesfield was the seat of a Benedictine priory, which passed to
+the Carthusians in the 14th century. Cutlery and tools are
+largely manufactured, and there are coal-mines, paper mills and
+iron and fire-clay works. After the inclusion within the county
+borough of Sheffield of part of the civil parish of Ecclesfield in
+1901, the population was 18,324.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESHALL,<a name="ar114" id="ar114"></a></span> a market town in the north-western parliamentary
+division of Staffordshire, England; 7 m. N.W. from
+Stafford, and 4 W. of Norton Bridge station on the London &amp;
+North-Western main line. Pop. (1901) 3799. The church of the
+Holy Trinity, one of the most noteworthy in Staffordshire, is
+principally Early English, and has fine stained glass. Several
+bishops of Lichfield are buried here, as Eccleshall Castle was the
+episcopal residence from the 13th century until 1867. Of this the
+ancient remains include a picturesque tower and bridge. To the
+west on the borders of Shropshire is Blore Heath, the scene of a
+defeat of the Lancastrians by the Yorkists in 1459.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIA<a name="ar115" id="ar115"></a></span> (Gr. <span class="grk" title="ekklêsia">&#7952;&#954;&#954;&#955;&#951;&#963;&#943;&#945;</span>, from <span class="grk" title="ek">&#7952;&#954;</span>, out, and <span class="grk" title="kalein">&#954;&#945;&#955;&#949;&#8150;&#957;</span>, to call), in
+ancient Athens, the general assembly of all the freemen of the
+state. In the primitive unorganized state the king was theoretically
+absolute, though his great nobles meeting in the Council
+(see <span class="sc"><a href="#artlinks">Boul&#275;</a></span>) were no doubt able to influence him considerably.
+There is, however, no doubt that in the earliest times the free
+people, <i>i.e.</i> the fighting force of the state, were called together to
+ratify the decisions of the king, and that they were gradually able
+to enforce their wishes against those of the nobles. In Athens,
+as in Rome, where the Plebs succeeded in their demand for the
+codification of the laws (the Twelve Tables), it was no doubt
+owing to the growing power of the people meeting in the Agora
+that Draco was entrusted with the task of publishing a code of
+law and so putting an end to the arbitrary judicature of the
+aristocratic party. But there is no evidence that the Ecclesia
+had more than a <i>de facto</i> existence before Solon&rsquo;s reforms.</p>
+
+<p>The precise powers which Solon gave the people are not known.
+It is clear that the executive power in the state (see <span class="sc"><a href="#artlinks">Archon</a></span>) was
+still vested in the Eupatrid class. It is obvious, therefore, that a
+moderate reformer would endeavour to give to the people some
+control over the magistracy. Now in speaking of the Thetes
+(the lowest of the four Solonian classes; see <span class="sc"><a href="#artlinks">Solon</a></span>), Aristotle&rsquo;s
+<i>Constitution of Athens</i> says that Solon gave them merely &ldquo;a
+share in the Ecclesia and the Law Courts,&rdquo; and in the <i>Politics</i> we
+find that he gave them the right of electing the magistrates and
+receiving their accounts at the end of the official year. Thus it
+seems that the &ldquo;mixed&rdquo; character of Solon&rsquo;s constitution
+consisted in the fact that though the officials of the state were
+still necessarily Eupatrid, the Ecclesia elected those of the
+Eupatrids whom they could trust, and further had the right of
+criticizing their official actions. Secondly, all our accounts agree
+that Solon admitted the Thetes to the Ecclesia, thus recognizing
+them as citizens. Under Cleisthenes the Ecclesia remained the
+sovereign power, but the Council seems to have become to
+some extent a separate administrative body. The relation of
+Boul&#275; and Ecclesia in the Cleisthenic democracy was of the
+<span class="pagenum"><a name="page848" id="page848"></a>848</span>
+greatest importance. The Ecclesia alone, a heterogeneous body of
+untrained citizens, could not have passed, nor even have drawn
+up intelligible measures; all the preliminary drafting was done
+by the small committee of the Boul&#275; which was in session at any
+particular time. In the 5th century the functions of the Ecclesia
+and the popular courts of justice were vastly increased by the
+exigencies of empire. At the beginning of the 4th century <span class="scs">B.C.</span>
+the system of payment was introduced (see below). In 308 <span class="scs">B.C.</span>
+Demetrius of Phalerum curtailed the power of the Ecclesia by the
+institution of the <i>Nomophylaces</i> (Guardians of the Law), who
+prevented the Ecclesia from voting on an illegal or injurious
+motion. Under Roman rule the powers of the Ecclesia and the
+popular courts were much diminished, and after 48 <span class="scs">B.C.</span> (the
+franchise being frequently sold to any casual alien) the Demos
+(people) was of no importance. They still assembled to pass
+psephisms in the theatre and to elect strategi, and, under Hadrian,
+had some small judicial duties, but as a governing body the
+Ecclesia died when Athens became a <i>civitas libera</i> under Roman
+protection.</p>
+
+<p><i>Constitution and Functions.</i>&mdash;Throughout the period of
+Athenian greatness the Ecclesia was the sovereign power, not only
+in practice but also in theory. The assembly met in early times
+near the sanctuary of Aphrodite Pandemus (<i>i.e.</i> south of the
+Acropolis), but, in the 5th and 4th centuries, the regular place of
+meeting was the Pnyx. From the 5th century it met sometimes
+in the theatre, which in the 3rd century was the regular place.
+From Demosthenes we learn that in his time special meetings
+were held at Peiraeus, and, in the last centuries <span class="scs">B.C.</span>, meetings
+were held at Athens and Peiraeus alternately. Certain meetings,
+however, for voting ostracism (<i>q.v.</i>) and on questions affecting
+individual status took place in the Agora. Meetings were
+(1) ordinary, (2) extraordinary, and (3) convened by special
+messengers (<span class="grk" title="kyriai">&#954;&#973;&#961;&#953;&#945;&#953;</span>, <span class="grk" title="synklêtoi">&#963;&#973;&#947;&#954;&#955;&#951;&#964;&#959;&#953;</span> and <span class="grk" title="kataklêtoi">&#954;&#945;&#964;&#940;&#954;&#955;&#951;&#964;&#959;&#953;</span>), these last
+being called when it was desirable that the country people should
+attend. At ordinary meetings the attendance was practically
+confined to Athenian residents. According to Aristotle there
+were four regular meetings in each prytany (see <span class="sc"><a href="#artlinks">Boul&#275;</a></span>); probably
+only the first of these was called <span class="grk" title="kyria">&#954;&#965;&#961;&#943;&#945;</span>. It is certain, however,
+that the four meetings did not fall on regular days, owing to
+the occurrence of feast days on which no meeting could take place.
+In the <span class="grk" title="kyria ekklêsia">&#954;&#965;&#961;&#943;&#945; &#7952;&#954;&#954;&#955;&#951;&#963;&#943;&#945;</span> of each month took place the <i>Epicheirotonia</i>
+(monthly inquiry) of the state officials, and if it proved
+unsatisfactory a trial before the Heliaea was arranged; the
+council reported on the general security and the corn-supply,
+and read out lists of vacant inheritances and unmarried
+heiresses. In the sixth prytany of each year at the <span class="grk" title="kyria ekklêsia">&#954;&#965;&#961;&#943;&#945; &#7952;&#954;&#954;&#955;&#951;&#963;&#943;&#945;</span>
+the question whether ostracism should take place that year was
+put to the vote. For all meetings it was usual that the Prytaneis
+should give five days&rsquo; notice in the form of a <i>programma</i> (agenda).
+On occasions of sudden importance the herald of the council
+summoned the people with a trumpet, and sometimes special
+messengers were despatched to &ldquo;bring in&rdquo; the country people
+(<span class="grk" title="katakalein">&#954;&#945;&#964;&#945;&#954;&#945;&#955;&#949;&#8150;&#957;</span>).</p>
+
+<p>After the archonship of Solon all Athenians over the age of
+eighteen were eligible to attend the assembly, save those who
+for some reason had suffered <i>atimia</i> (loss of civil rights). To
+prevent the presence of any disqualified persons, six <i>lexiarchs</i>
+with thirty assistants were present with the deme-rolls in their
+hands. These officers superintended the payment in the
+4th century and probably the <i>toxotae</i> (police) also, whose duty
+it was before the introduction of pay to drive the people out
+of the Agora into the Ecclesia with a rope steeped in red dye
+which they stretched out and used as a draw net (see
+Aristoph. <i>Acharn.</i> 22 and <i>Eccles.</i> 378). The introduction
+of pay, which belongs to the early years of the 4th century
+and by the <i>Constitution</i> (<i>c.</i> 41 ad fin.) is attributed to Agyrrhius,
+a statesman of the restored democracy, was a device to secure
+a larger attendance. The rate rose from one to two obols and
+then to three obols (Aristoph. <i>Eccles.</i> 300 sqq.), while at the time
+of Aristotle it was one and a half drachmas for the <span class="grk" title="kyria ekklêsia">&#954;&#965;&#961;&#943;&#945; &#7952;&#954;&#954;&#955;&#951;&#963;&#943;&#945;</span>
+and one drachma for other meetings. Probably those who were
+late did not receive payment.</p>
+
+<p><i>Procedure.</i>&mdash;The proceedings opened with formalities: the
+purification by the <i>peristiarchs</i>, who carried round slain sucking
+pigs; the curse against all who should deceive the people; the
+appointment (in the 4th century) of the <i>proedri</i> and their
+<i>epistates</i> (see <span class="sc"><a href="#artlinks">Boul&#275;</a></span>); the report as to the weather-omens. The
+assembly was always dismissed if there were thunder, rain or
+an eclipse. These formalities over, the Prytaneis communicated
+the <i>probouleuma</i> of the council, without which the Ecclesia could
+not debate. This recommendation either submitted definite
+proposals or merely brought the agenda before the assembly.
+Its importance lay largely in the fact that it <i>explained</i> the business
+in hand, which otherwise must often have been beyond the
+grasp of a miscellaneous assembly. After the reading, a preliminary
+vote was taken as to whether the council&rsquo;s report should
+be accepted <i>en bloc</i>. If it was decided to discuss, the herald called
+upon people to speak. Any person, without distinction of age
+or position, might obtain leave to speak, but it seems probable
+that the man who had moved the recommendation previously
+in the council would advocate it in the assembly. The council
+was, therefore, a check on the assembly, but its powers were to
+some extent illusory, because any member of the assembly (1)
+might propose an amendment, (2) might draw up a new resolution
+founded on the principal motion, (3) might move the rejection
+of the motion and the substitution of another, (4) might bring
+in a motion asking the council for a recommendation on a
+particular matter, (5) might petition the council for leave to
+speak on a given matter to the assembly. Voting usually was
+by show of hands, but in special cases (ostracism, &amp;c.) by ballot
+(<i>i.e.</i> by casting pebbles into one of two urns). The decision of
+the assembly was called a <i>psephism</i> and had absolute validity.
+These decisions were deposited in the Metroön where state
+documents were preserved; peculiarly important decrees were
+inscribed also on a column (<i>st&#275;l&#275;</i>) erected on the Acropolis.
+It has been shown that the power of the council was far from
+sufficient. The real check on the vagaries of amateur legislators
+was the Graph&#275; Paranom&#333;n. Any man was at liberty to give
+notice that he would proceed against the mover of a given
+resolution either before or after the voting in the Ecclesia. A
+trial in a Heliastic court was then arranged, and the plaintiff
+had to prove that the resolution in question contravened an
+existing law. If this contention were upheld by the court, when
+the case was brought to it by the Thesmothetae, the resolution
+was annulled, and the defendant had to appear in a new trial
+for the assessment of the penalty, which was usually a fine,
+rarely death. Three convictions under this law, however, involved
+a certain loss of rights; the loser could no longer move
+a resolution in the Ecclesia. After the lapse of a year the mover
+of a resolution could not be attacked. In the 4th century the
+Graph&#275; Paranom&#333;n took the place of Ostracism (<i>q.v.</i>). In the
+5th century it was merely an arrangement whereby the people
+sitting as sworn juries ratified or annulled their own first decision
+in the Ecclesia.</p>
+
+<p><i>Revision of Laws.</i>&mdash;In the 4th century, the assembly annually,
+on the eleventh day of Hecatombaeon (the first day of the
+official year), took a general vote on the laws, to decide whether
+revision was necessary. If the decision was in favour of alteration,
+it was open to any private citizen to put up notice of amendments.
+The Nomothetae, a panel selected by the Prytaneis from the
+Heliaea, heard arguments for and against the changes proposed
+and voted accordingly. Against all new laws so passed, there
+lay the Graph&#275;; Paranom&#333;n. Thus the Nomothetae, not the
+Ecclesia, finally passed the law.</p>
+
+<p><i>Judicial Functions.</i>&mdash;The Ecclesia heard cases of Probol&#275;
+and Eisangelia (see <span class="sc"><a href="#artlinks">Greek Law</a></span>). The Probol&#275; was an action
+against sycophants and persons who had not kept their promises
+to the people, or had disturbed a public festival. The verdict
+went by show of hands, but no legal consequences ensued; if
+the plaintiff demanded punishment he had to go to the Heliaea
+which were not at all bound by the previous vote in the Ecclesia.
+Cases of Eisangelia in which the penalty exceeded the legal
+competence of the council came before the Ecclesia in the form
+of a <i>probouleuma</i>. To prevent vexatious accusations, it was
+<span class="pagenum"><a name="page849" id="page849"></a>849</span>
+(at some date unknown) decided that the accuser who failed
+to obtain one-fifth of the votes should be fined 1000 drachmas
+(£40). (For the procedure in case of <span class="sc"><a href="#artlinks">Ostracism</a></span> see that article.)</p>
+
+<p><i>Summary.</i>&mdash;Thus it will be seen that the Ecclesia, with no
+formal organization, had absolute power save for the Graph&#275;
+Paranom&#333;n (which, therefore, constituted the dicasteries in one
+sense the sovereign power in the state). It dealt with all matters
+home and foreign. Every member could initiate legislation,
+and, as has been shown, the power of the council was merely
+formal. As against this it must be pointed out that it was
+by no means a representative assembly in practice. The phrase
+used to describe a very special assembly (<span class="grk" title="kataklêtos ekklêsia">&#954;&#945;&#964;&#940;&#954;&#955;&#951;&#964;&#959;&#962; &#7952;&#954;&#954;&#955;&#951;&#963;&#943;&#945;</span>)
+shows that ordinarily the country members did not attend
+(<span class="grk" title="katakalein">&#954;&#945;&#964;&#945;&#954;&#945;&#955;&#949;&#8150;&#957;</span> always involving the idea of motion from a distance
+towards Athens), and Thucydides says that 5000 was the maximum
+attendance, though it must be remembered that he is
+speaking of the time when the number of citizens had been much
+reduced owing to the plague and the Sicilian expedition. From
+this we understand the necessity of payment in the 4th century,
+although in that period the Ecclesia was supreme (<i>Constitution
+of Athens</i>, xli. 2). The functions of the Ecclesia thus differed
+in two fundamental respects from those which are in modern
+times associated with a popular assembly. (1) It did not exercise,
+at least in the period as to which we are best instructed, the power
+of law-making (<span class="grk" title="nomothesia">&#957;&#959;&#956;&#959;&#952;&#949;&#963;&#943;&#945;</span>) in the strict sense. It must be
+remembered, however, in qualification of this statement that it
+possessed the power of passing <i>psephismata</i> which would in many
+cases be regarded as law in the modern sense. (2) The Ecclesia
+was principally concerned with the supervision of administration.
+Much of what we regard as executive functions were discharged
+by the Ecclesia.</p>
+
+<div class="condensed">
+<p>With this article compare those on <span class="sc"><a href="#artlinks">Solon</a></span>; <span class="sc"><a href="#artlinks">Boule</a></span>; <span class="sc"><a href="#artlinks">Areopagus</a></span>;
+<span class="sc"><a href="#artlinks">Greek Law</a></span>, and, for other ancient popular assemblies, <span class="sc"><a href="#artlinks">Apella</a></span>;
+<span class="sc"><a href="#artlinks">Comitia</a></span>. See also A.H.J. Greenidge, <i>Handbook of Greek Constitutional
+History</i> (1896); Gilbert, <i>Greek Constitutional Antiquities</i>
+(trans. Brooks and Nicklin, 1895); Schömann, <i>De comitiis Atheniensium</i>;
+L. Schmidt, &ldquo;De Atheniensis reipublicae indole democratica&rdquo;
+in <i>Ind. Lect.</i> (Marburg, 1865); J.W. Headlam, <i>Election by Lot at
+Athens</i> (Cambridge, 1891). See also the histories of Greece by Meyer,
+Busolt, Grote, Evelyn Abbott, and J.E. Sandys&rsquo; edition of the <i>Constitution
+of Athens</i> (1892); for a comparative study, E.A. Freeman,
+<i>Comparative Politics</i>.</p>
+</div>
+<div class="author">(J. M. M.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIASTES<a name="ar116" id="ar116"></a></span> (Heb. <span title="Kohelet">&#1511;&#1492;&#1500;&#1514;</span>, <i>Kohelet</i>, &ldquo;Koheleth&rdquo;; Sept.
+<span class="grk" title="ekklêsiastês">&#7952;&#954;&#954;&#955;&#951;&#963;&#953;&#945;&#963;&#964;&#942;&#962;</span>; Jerome <i>concionator</i>), one of the Wisdom Books
+of the Old Testament (see <span class="sc"><a href="#artlinks">Wisdom Literature</a></span>). The book, as
+it stands, is a collection of the discourses, observations and
+aphorisms of a sage called Koheleth, a term the precise meaning
+of which is not certain. The Greek <i>ecclesiastes</i> means one who
+takes part in the deliberations of an assembly (<i>ecclesia</i>), a debater
+or speaker in an assembly (Plato, <i>Gorgias</i>, 452 E), and this is the
+general sense of the Hebrew word. Its form (singular feminine)
+has been supposed to be the adoption or imitation of the Arabic
+employment of a fem. sing. as the designation of a high official
+person, as is the case in the title <i>caliph</i> (whence the rendering
+in the margin of the Revised Version, &ldquo;Great orator&rdquo;); but
+the adoption of an Arabic idiom is not probable. This usage is
+not Hebrew; it is not found either in the Old Testament or in
+the later (Mishnaic) Hebrew. The form may have been suggested
+by that of the Hebrew word for &ldquo;wisdom.&rdquo; <i>Koheleth</i>, however,
+is employed in the book not as a title of wisdom (for &ldquo;wisdom&rdquo;
+is never the speaker), but as the independent name of the sage.
+It is intended to represent him as a member of an assembly
+(<i>Kahal</i>)&mdash;not the Jewish congregation, but a body of students
+or inquirers, such as is referred to in xii. 9-11, a sort of collegium,
+of which he was the head; and as instructor of this body
+he gives his criticism of life. The author begins, indeed,
+with identifying his sage with King Solomon (i. 12-ii. 11, 12b);
+but he soon abandons this literary device, and speaks in his
+own name. The rendering &ldquo;preacher&rdquo; has a misleading
+connotation.</p>
+
+<p>In the book as we have it there is no orderly exposition of a
+theory; it rather has the appearance of a collection of remarks
+jotted down by a pupil (somewhat after the manner of Xenophon&rsquo;s
+<i>Memorabilia</i>), or of extracts from a sage&rsquo;s notebook. It
+is, however, characterized throughout (except in some scribal
+additions) by a definite thought, and pervaded by a definite tone
+of feeling. The keynote is given in the classic phrase with which
+the discussion opens and with which it closes: &ldquo;Vanity of
+vanities (<i>i.e.</i> absolute vanity), all<a name="fa1g" id="fa1g" href="#ft1g"><span class="sp">1</span></a> is vanity!&rdquo; Life, says the
+author, has nothing of permanent value to offer. His attitude
+is one not of bitterness but of calm hopelessness, with an occasional
+tinge of disgust or contempt. He fancies that he has tried
+or observed everything in human experience, and his deliberate
+conclusion is that nothing is worth doing. He believes in an all-powerful
+but indifferent God, and is himself an observer of
+society, standing aloof from its passions and ambitions, and
+interested only in pointing out their emptiness.</p>
+
+<p>This general view is set forth in a number of particular
+observations.</p>
+
+<p>1. His fundamental proposition is that there is a fixed,
+unchangeable order in the world, a reign of inflexible law (i. 4-11,
+iii. 1-11, 14, 15, vii. 13, viii. 5-9): natural phenomena, such as
+sunrise and sunset, recur regularly; for everything in human
+experience a time has been set; birth and death, building up
+and destroying, laughing and weeping, silence and speech, love
+and hate, war and peace, are to be regarded not as utterances
+of a living, self-directing world, but as incidents in the work of a
+vast machine that rolls on for ever; there is an endless repetition&mdash;nothing
+is new, nothing is lost; if one thinks he has found
+something new, inquiry shows that it was in existence long ago;
+God, the author of all, seeks out the past in order to make it once
+more present; it is impossible to add to or take from the content
+of the world, impossible to change the nature of things, to effect
+any radical betterment of life; the result is unspeakable weariness&mdash;a
+depressing series of sights and sounds. No goal or
+purpose is discoverable in this eternal round; if the sun rises
+and goes on his journey through the sky, it is merely to come
+back to the place where he rose; rivers flow for ever into the
+sea without filling it. To what end was the world created?
+It is impossible to say. Such is Koheleth&rsquo;s view of life, and it is
+obvious that such a conception of an aimless cosmos is thoroughly
+non-Jewish, if we may judge Jewish thought by the great body
+of the extant literature.</p>
+
+<p>2. Further, says Koheleth, man is impelled to study the world,
+but under the condition that he shall never comprehend it
+(iii. 11, vii. 23, 24, viii. 16, 17). As to the meaning of the
+Hebrew term <i>olam</i> in iii. 11, there are various opinions, but
+&ldquo;world&rdquo; appears to be the rendering favoured by the connexion:
+&ldquo;God has made everything beautiful in its time, and
+has put the <i>olam</i> into men&rsquo;s minds, yet so that they cannot understand
+His work&rdquo;: the <i>olam</i>, the sum of phenomena, is God&rsquo;s
+work. The word is not found in this sense elsewhere in the Old
+Testament, but it so occurs in the Mishna (<i>Pirke Aboth</i>, iv. 7),
+and the vocabulary of Ecclesiastes is admittedly similar to that
+of the Mishna. Only here in the Old Testament does it stand
+as a simple isolated noun; elsewhere it is the definition of a
+noun (in &ldquo;everlasting covenant,&rdquo; &amp;c.), or it is preceded by a
+preposition, in the phrases &ldquo;for ever,&rdquo; &ldquo;of old,&rdquo; or it stands
+alone (sing. or plur.) in the same adverbial sense, &ldquo;for ever.&rdquo;
+The word means first a remote point in past or future, then a
+future point without limit of time, then a period of history, and
+finally the world considered as a mass of human experiences
+(cf. <span class="grk" title="aiôn">&#945;&#7984;&#974;&#957;</span>). The renderings &ldquo;eternity&rdquo; and &ldquo;future&rdquo; in
+the present passage are unsatisfactory; the former has an
+inappropriate metaphysical connotation, and yields no distinct
+sense; the latter does not suit the connexion, though there is
+reference to the future elsewhere (ix. 1). God, the text here
+declares, has made the world an object of man&rsquo;s thought, yet
+so that man can never find out the work that God has done
+(iii. 11). The reference seems to be not so much to the variety
+and complexity of phenomena as to the impossibility of construing
+them rationally or in such a way that man may foresee and
+provide for his future. Man is in the clutches of fate (ix. 11, 12):
+there is no observable relation between exertion and result in
+life: the race is not to the swift nor the battle to the strong;
+<span class="pagenum"><a name="page850" id="page850"></a>850</span>
+success does not attend wisdom, knowledge and skill; men are
+like fish taken in a net or birds caught in a snare.</p>
+
+<p>3. Human life, Koheleth declares, is unsatisfying. He
+inquired, he says, into everything that is done by men under
+the sun (i. 12-16): God has inflicted on men a restless desire for
+movement and work<a name="fa2g" id="fa2g" href="#ft2g"><span class="sp">2</span></a>, yet life is but a catalogue of fruitless
+struggles. He gives a number of illustrations. In his character
+of king he tried all the bodily pleasures of life (ii. 1-11): he had
+houses, vineyards, gardens, parks, ponds, forests, servants,
+flocks and herds, treasures of gold and silver, singers, wives;
+all these he set himself to enjoy in a rational way&mdash;indeed, he
+found a certain pleasure in carrying out his designs, but, when all
+was done, he surveyed it only to see that it was weary and unprofitable.
+Dropping the rôle of Solomon and speaking as an
+observer of life, the author declares (iv. 4) that the struggle for
+success is the result of rivalry among men, which has no worthy
+outcome. The securing of riches is a fallacious achievement,
+for often wealth perishes by some accident (v. 13 f.), or its
+possessor is unable to enjoy it (vi. 1-3<i>a</i>), or he has no one to
+whom to leave it, and he cannot keep it&mdash;naked man comes into
+the world, naked he goes out. He does not consider the possibility
+of deriving enjoyment from wealth by helping the poor or
+encouraging learning (this latter, indeed, he looks on as vanity),
+and in general he recognizes no obligation on the part of a man
+to his fellows. A noteworthy survival of an old belief is found
+in vi. 3: though a man have the great good fortune to live long
+and to have many children, yet, if he have not proper burial
+the blank darkness of an untimely birth is better than he: this
+latter is merely the negation of existence; the former, it appears
+to be held, is positive misfortune, the loss of a desirable place in
+Sheol, though elsewhere (ix. 5) existence in Sheol is represented
+as the negation of real life. It is not necessary to suppose that
+the writer has here any particular case in mind.</p>
+
+<p>If wealth be thus a vain thing, yet a sage might be supposed
+to find satisfaction in wisdom, that is, practical good sense and
+sagacity; but this also the author puts aside as bringing no
+lasting advantage, since a wise man must finally give up the fruit
+of his wisdom to someone else, who may be a fool, and in any
+case the final result for both fools and wise men is the same&mdash;both
+are forgotten (ii. 12-23). A particular instance is mentioned
+(ix. 13-15) of a <span class="correction" title="amended from beleagured">beleaguered</span> city saved by a wise man; but the
+man happened to be poor, and no one remembered him. The
+whole constitution of society, in fact, seems to the sage a lamentable
+thing: the poor are oppressed, the earth is full of their cries,
+and there is no helper (iv. 1); strange social upheavals may be
+seen: the poor<a name="fa3g" id="fa3g" href="#ft3g"><span class="sp">3</span></a> set in high places, the rich cast down, slaves
+on horseback, princes on foot (x. 5-7). He permits himself a
+sweeping generalization (vii. 25-28): human beings as a rule are
+bad: one may occasionally find a good man, never a good
+woman&mdash;woman is a snare and a curse. He (or an editor) adds
+(vii. 29) that this condition of things is due to social development:
+man was created upright (Gen. i. 27; Enoch lxix. 11), but in the
+course of history has introduced corrupting complications into
+life.</p>
+
+<p>4. The natural outcome of these experiences of the author is
+that he cannot recognize a moral government of the world.
+He finds, like Job, that there are good men who die prematurely
+notwithstanding their goodness, and bad men who live long
+notwithstanding their badness (vii. 15), though long life, it is
+assumed, is one of the great blessings of man&rsquo;s lot; and in
+general there is no moral discrimination in the fortunes of men
+(viii. 14, ix. 2).</p>
+
+<p>5. There is no sacredness or dignity in man or in human life:
+man has no pre-eminence over beasts, seeing that he and they
+have the same final fate, die and pass into the dust, and no one
+knows what becomes of the spirit, whether in man&rsquo;s case it goes
+up to heaven, and in the case of beasts goes down into Sheol&mdash;death
+is practically the end-all; and so poor a thing is life that
+the dead are to be considered more fortunate than the living,
+and more to be envied than either class is he who never came
+into existence (iv. 2, 3). It is a special grievance that the wicked
+when they die are buried with pomp and ceremony, while men
+who have acted well are forgotten<a name="fa4g" id="fa4g" href="#ft4g"><span class="sp">4</span></a> in the city (viii. 10).</p>
+
+<p>6. That the author does not believe in a happy or active future
+life appears in the passage (iv. 2, 3) quoted above. The old
+Hebrew view of the future excluded from Sheol the common
+activities of life and also the worship of the national god (Isa.
+xxxviii. 18); he goes even beyond this in his conception of the
+blankness of existence in the underworld. The living, he says,
+at least know that they shall die, but the dead know nothing&mdash;the
+memory of them, their love, hate and envy, perishes, they
+have no reward, no part in earthly life (ix. 5, 6); there is
+absolutely no knowledge and no work in Sheol (ix. 10). His
+conclusion is that men should do now with all their might what
+they have to do; the future of man&rsquo;s vital part, the spirit, is
+wholly uncertain.</p>
+
+<p>7. His conception of God is in accord with these views.
+God for him is the creator and ruler of the world, but hardly
+more; he is the master of a vast machine that grinds out human
+destinies without sympathy with man and without visible
+regard for what man deems justice&mdash;a being to be acknowledged
+as lord, not one to be loved. There can thus be no social contact
+between man and God, no communion of soul, no enthusiasm
+of service. Moral conduct is to be regulated not by divine law
+(of this nothing is said) but by human experience. The author&rsquo;s
+theism is cold, spiritless, without influence on life.</p>
+
+<p>If now the question be asked what purpose or aim a man can
+have, seeing that there is nothing of permanent value in human
+work, an answer is given which recurs, like a refrain, from the
+beginning to the end of the book, and appears to be from the
+hand of the original author: after every description of the vanity
+of things comes the injunction to enjoy such pleasures as may fall
+to one&rsquo;s lot (ii. 24, 25, iii. 12, 13, 22, v. 18, 19, viii. 15,
+ix. 7-10, xi. 7-xii. 7). Elsewhere (ii.), it is true, it is said that
+there is no lasting satisfaction in pleasure; but the sage may
+mean to point out that, though there is no permanent outcome
+to life, it is the part of common-sense to enjoy what one has.
+The opportunity and the power to enjoy are represented as being
+the gift of God; but this statement is not out of accord with
+the author&rsquo;s general position, which is distinctly theistic. All the
+passages just cited, except the last (xi. 7-xii. 7), are simple and
+plain, but the bearing of the last is obscured by interpolations.
+Obviously the purpose of the paragraph is to point out the
+wisdom of enjoying life in the time of youth while the physical
+powers are fresh and strong, and the impotency of old age has
+not yet crept in. Omitting xi. 8<i>c</i>, 9<i>b</i>, 10<i>b</i>, xii. 1<i>a</i>, the passage
+will read: &ldquo;Life is pleasant in the bright sunshine&mdash;however
+long a man may live, he must be cheerful always, only remembering
+that dark days will come. Let the young man enjoy all the
+pleasures of youth, putting away everything painful, before the
+time comes when his bodily powers decay and he can enjoy
+nothing.&rdquo; To relieve the apparent Epicureanism of this passage,
+an editor has inserted reminders of the vanity of youthful
+pleasures, and admonitions to remember God and His judgment.
+The author, however, does not recommend dissipation, and does
+not mean to introduce a religious motive&mdash;he offers simply a
+counsel of prudence. The exhortation to remember the Creator
+in the days of youth, though it is to be retained in the margin
+as a pious editorial addition, here interrupts the line of thought.
+In xii. 1a some critics propose to substitute for &ldquo;remember thy
+Creator&rdquo; the expression of xi. 9, &ldquo;let thy heart cheer thee&rdquo;;
+but the repetition is improbable. Others would read: &ldquo;remember
+thy cistern&rdquo; (Bickell), or &ldquo;thy well&rdquo; (Haupt), that
+is, thy wife. The wife is so called in Prov. v. 15-19 in an elaborate
+poetical figure (the wife as a source of bodily pleasure), in which
+the reference is clear from the context; but there is no authority,
+in the Old Testament or in other literature of this period, for
+<span class="pagenum"><a name="page851" id="page851"></a>851</span>
+taking the term as a simple prose designation of a wife. Nor
+would this reference to the wife be appropriate in the connexion,
+since the writer&rsquo;s purpose is simply to urge men to enjoy life
+while they can. The paragraph (and the original book) concludes
+with a sustained and impressive figure, in which the failing body
+of the old man is compared to a house falling into decay: first,
+the bodily organs (xii. 3, 4<i>a</i>): the keepers of the house (the arms
+and hands) tremble, the strong men (the legs and perhaps the
+backbone) are bent, the grinding women (the teeth) cease to
+work, those that look out of the windows (the eyes) are darkened,
+the street-doors are shut, the sound of the mill being low (apparently
+a summary statement of the preceding details: communication
+with the outer world through the senses is cut off,
+the performance of bodily functions being feeble); the rest of
+v. 4 may refer to the old man&rsquo;s inability to make or hear music:
+in the house there is no sound of birds<a name="fa5g" id="fa5g" href="#ft5g"><span class="sp">5</span></a> or of singers, there are
+none of the artistic delights of a well-to-do household; further
+(v. 5<i>a</i>) the inmates of the house fear dangers from all powerful
+things and persons (the old man is afraid of everything), the
+almond tree blossoms (perhaps the hair turns white). The two
+next clauses are obscure.<a name="fa6g" id="fa6g" href="#ft6g"><span class="sp">6</span></a> Then comes the end: man goes to his
+everlasting home; the dust (the body) returns to the earth
+whence it came (Gen. ii. 7), and the breath of life, breathed by
+God into the body, returns to him who gave it. This last clause
+does not affirm the immortality of the soul; it is simply an
+explanation of what becomes of the vital principle (the &ldquo;breath
+of life&rdquo; of Gen. ii. 7); its positive assertion is not in accord
+with the doubt expressed in iii. 21 (&ldquo;who knows whether the
+spirit of man goes upward?&rdquo;), and it seems to be from another
+hand than that of the author of the original book.</p>
+
+<p>There are other sayings in the book that appear to be at
+variance with its fundamental thought. Wisdom is praised in a
+number of passages (iv. 13, vii. 5, 11, 12, 19, viii. 1, ix. 16, 17,
+x. 2, 3), though it is elsewhere denounced as worthless. It may
+be said that the author, while denying that wisdom (practical
+sagacity and level-headedness) can give permanent satisfaction,
+yet admits its practical value in the conduct of life. This may
+be so; but it would be strange if a writer who could say, &ldquo;in
+much wisdom is much grief,&rdquo; should deliberately laud wisdom.
+The question is not of great importance and may be left undecided.
+It may be added that there are in the book a number
+of aphorisms about fools (v. 3[4], vii. 5, 6, x. 1-3, 12-15) quite
+in the style of the book of Proverbs, some of them contrasting
+the wise man and the fool; these appear to be the insertions of
+an editor. Further, it may be concluded with reasonable certainty
+that the passages that affirm a moral government of the world are
+additions by pious editors who wished to bring the book into
+harmony with the orthodox thought of the time. Such assertions
+as those of ii. 26 (God gives joy to him who pleases him,
+<span class="correction" title="amended from amd">and</span> makes the sinner toil to lay up for the latter), viii. 12 (it
+shall be well with those that fear God, but not with the wicked),
+xii. 13 f. (man&rsquo;s duty is simply to obey the commands of God,
+for God will bring everything into judgment) are irreconcilable
+with the oft-repeated statement that there is no difference in
+the earthly lots of the righteous and the wicked, and no ethical
+life after death.</p>
+
+<p>Many practical admonitions and homely aphorisms are
+scattered through the book: iv. 5, quiet is a blessing; iv. 9-12,
+two are better than one; iv. 17 (Eng. v. 1), be reverent in visiting
+the house of God (the temple and the connected buildings)&mdash;to
+listen (to the service of song or the reading of Scripture)
+is better than to offer a foolish (thoughtless) sacrifice; v. 1
+(2), be sparing of words in addressing God; v. 1-5 (2-6), pay
+your vows&mdash;do not say to the priest&rsquo;s messenger that you made
+a mistake; vii. 2-4, sorrow is better than mirth; vii. 16-18,
+be not over-righteous (over-attentive to details of ritual and
+convention) or over-wicked (flagrantly neglectful of established
+beliefs and customs); here &ldquo;righteous&rdquo; and &ldquo;wicked&rdquo; appear
+to be technical terms designating two parties in the Jewish
+world of the 2nd and 1st centuries <span class="scs">B.C.</span>, the observers and the
+non-observers of the Jewish ritual law; these parties represent
+in a general way the Pharisees and the Sadducees; viii. 2-4,
+x. 20, it is well to obey kings and to be cautious in speaking
+about them, for there are talebearers everywhere; vii. 20, no
+man is free from sin; vii. 21, do not listen to all that you may
+overhear, lest you hear yourself ill spoken of; ix. 4, a living
+dog is better than a dead lion; xi. 1-6, show prudence and
+decision in business; do not set all your goods on one venture;
+act promptly and hope for the best. At the close of the book
+(xii. 9-12) there are two observations that appear to be editorial
+recommendations and cautions. First, Koheleth is endorsed
+as an industrious, discriminating and instructive writer.
+Possibly this is in reply to objections that had been made to
+what he had written. There follows an obscure passage (<i>v.</i> 11)
+which seems to be meant as a commendation of the teaching
+of the sages in general: their words are said to be like goads
+(inciting to action) and like nails driven in a building (giving
+firmness to character); they issue from masters of assemblies,<a name="fa7g" id="fa7g" href="#ft7g"><span class="sp">7</span></a>
+heads of academies (but not of the Sanhedrin). The succeeding
+clause &ldquo;they are given from one shepherd&rdquo; may refer to a
+collection or revision by one authoritative person, but its relevancy
+is not obvious. The &ldquo;shepherd&rdquo; cannot be God (Gen.
+xlix. 24; Ps. xxiii. 1); the poetical use of the word would not be
+appropriate here. The clause is possibly a gloss, a comment
+on the preceding expression. A caution against certain books
+is added (<i>v.</i> 12), probably works then considered harmful
+(perhaps philosophic treatises), of which, however, nothing
+further is known.</p>
+
+<p><i>Composition of the Book.</i>&mdash;If the analysis given above is
+correct, the book is not a unit; it contains passages mutually
+contradictory and not harmonizable. Various attempts have
+been made to establish its unity. The hypothesis of &ldquo;two
+voices&rdquo; is now generally abandoned; there is no indication of
+a debate, of affirmations and responses. A more plausible
+theory is that the author is an honest thinker, a keen observer
+and critic of life, who sees that the world is full of miseries and
+unsolved problems, regards as futile the attempts of his time
+to demonstrate an ethically active future life, and, recognizing
+a divine author of all, holds that the only wise course for men
+is to abandon the attempt to get full satisfaction out of the
+struggle for pleasure, riches and wisdom, and to content themselves
+with making the best of what they have. This conception
+of him is largely true, as is pointed out above, but it does not
+harmonize the contradictions of the book, the discrepancies
+between the piety of some passages and the emotional indifference
+toward God shown in others. Other of the Biblical Wisdom
+books (Job, Proverbs) are compilations&mdash;why not this? It is
+not necessary to multiply authors, as is done, for example, by
+Siegfried, who supposes four principal writers (a pessimistic
+philosopher, an Epicurean glossator, a sage who upholds the
+value of wisdom, and an orthodox editor) besides a number of
+annotators; it is sufficient to assume that several conservative
+scribes have made short additions to the original work. Nor is
+it worth while to attempt a logical or symmetrical arrangement
+of the material. It has been surmised (by Bickell) that the sheets
+of the original codex became disarranged and were rearranged
+incorrectly;<a name="fa8g" id="fa8g" href="#ft8g"><span class="sp">8</span></a> by other critics portions of the book are transferred
+<span class="pagenum"><a name="page852" id="page852"></a>852</span>
+hither and thither; in all cases the critic is guided in these
+changes by what he conceives to have been the original form of
+the book. But it is more probable that we have it in the form
+in which it grew up&mdash;a series of observations by the original
+author with interspersed editorial remarks; and it is better to
+preserve the existing form as giving a record of the process
+of growth.</p>
+
+<p><i>Date.</i>&mdash;As to the date of the book, though there are still
+differences of opinion among scholars, there is a gradual approach
+to a consensus. The Solomonic authorship has long since been
+given up: the historical setting of the work and its atmosphere&mdash;the
+silent assumption of monotheism and monogamy, the non-national
+tone, the attitude towards kings and people, the picture
+of a complicated social life, the strain of philosophic reflection&mdash;are
+wholly at variance with what is known of the 10th century
+<span class="scs">B.C.</span> and with the Hebrew literature down to the 5th or 4th
+century <span class="scs">B.C.</span> The introduction of Solomon, the ideal of wisdom,
+is a literary device of the later time, and probably deceived
+nobody. The decisive considerations for the determination of
+the date are the language, the historical background and the
+thought. The language belongs to the post-classical period of
+Hebrew. The numerous Aramaisms point to a time certainly
+not earlier than the 4th century <span class="scs">B.C.</span>, and probably (though the
+history of the penetration of Aramaic into Hebrew speech is
+not definitely known) not earlier than the 3rd century. More
+than this, there are many resemblances between the dialect of
+Koheleth and that of Mishna. Not only are new words employed,
+and old words in new significations, but the grammatical
+structure has a modern stamp&mdash;some phrases have the appearance
+of having been translated out of Aramaic into Hebrew.
+By about the beginning of our era the Jews had given up Hebrew
+and wrote in Aramaic; the process of expulsion had been going
+on, doubtless, for some time; but comparison with the later
+extant literature (<i>Chronicles</i>, the Hebrew <i>Ecclesiasticus</i> or
+<i>Ben-Sira</i>, <i>Esther</i>) makes it improbable that such Hebrew as
+that of Koheleth would have been written earlier than the
+2nd century <span class="scs">B.C.</span> (for details see Driver&rsquo;s <i>Introduction</i>). The
+general historical situation, also, presupposed or referred to, is
+that of the period from the year 200 <span class="scs">B.C.</span> to the beginning of our
+era; in particular, the familiar references to kings as a part of
+the social system, and to social dislocations (servants and princes
+changing places, x. 7), suggest the troublous time of the later
+Greek and the Maccabean rulers, of which the history of Josephus
+gives a good picture.</p>
+
+<p>The conception of the world and of human life as controlled
+by natural law, a naturalistic cosmos, is alien not only to the
+prophetic and liturgical Hebrew literature but also to Hebrew
+thought in general. Whether borrowed or not, it must be late;
+and its resemblance to Greek ideas suggests Greek influence.
+The supposition of such influence is favoured by some critics
+(Tyler, Plumptre, Palm, Siegfried, Cheyne in his <i>Jewish Religious
+Life after the Exile</i>, and others), rejected by some (Zeller, Renan,
+Kleinert and others). This disagreement comes largely from
+the attempts made to find definitely expressed Greek philosophical
+dogmas in the book; such formulas it has not, but
+the general air of Greek reflection seems unmistakable. <span class="correction" title="'the' originally repeated twice">The</span>
+scepticism of Koheleth differs from that of Job in quality and
+scope: it is deliberate and calm, not wrung out by personal
+suffering; and it relates to the whole course and constitution
+of nature, not merely to the injustices of fortune. Such a conception
+has a Greek tinge, and would be found in Jewish circles,
+probably, not before the 2nd century <span class="scs">B.C.</span></p>
+
+<p>A precise indication of date has been sought in certain supposed
+references or allusions to historical facts. The mention of persons
+who do not sacrifice or take oaths (ix. 2) is held by some to point
+to the Essenes; if this be so, it is not chronologically precise,
+since we have not the means of determining the beginning of
+the movement of thought that issued in Essenism. So also the
+coincidences of thought with <i>Ben-Sira</i> (<i>Ecclesiasticus</i>) are not
+decisive: cf. iii. 14 with <i>B.S.</i> xviii. 6; v. 2-6 (3-7) with <i>B.S.</i>
+xxxiv. 1-7; vii. 19 with <i>B.S.</i> xxxvii. 14; x. 8 with <i>B.S.</i> xxvii.
+26a; xi. 10 with <i>B.S.</i> xxx. 21; xii. 10, 11 with <i>B.S.</i> xxxix. 2 ff.,
+xii. 13 with <i>B.S.</i> xliii. 27; if there be borrowing in these passages,
+it is not clear on which side it lies; and it is not certain that there
+is borrowing&mdash;the thoughts may have been taken independently
+by the two authors from the same source. In any case, since
+<i>Ben-Sira</i> belongs to about 180 <span class="scs">B.C.</span>, the date of Koheleth, so
+far as these coincidences indicate it, would not be far from
+200 <span class="scs">B.C.</span> The contrast made in x. 16 f. between a king who is
+a boy and one who is of noble birth may allude to historical
+persons. The antithesis is not exact; we expect either &ldquo;boy
+and mature man&rdquo; or &ldquo;low-born and high-born.&rdquo; The &ldquo;child&rdquo;
+might be Antiochus V. (164 <span class="scs">B.C.</span>), or Ptolemy V., Epiphanes
+(204 <span class="scs">B.C.</span>), but the reference is too general to be decisive. The
+text of the obscure passage iv. 13-16 is in bad condition, and
+it is only by considerable changes that a clear meaning can be
+got from it. The two personages&mdash;the &ldquo;old and foolish king&rdquo;
+and the &ldquo;poor and wise youth&rdquo;&mdash;have been supposed (by Winckler)
+to be Antiochus Epiphanes (175-164 <span class="scs">B.C.</span>) and
+Demetrius (162-150 <span class="scs">B.C.</span>), or (by Haupt) Antiochus and the
+impostor Alexander Balas (150-146 <span class="scs">B.C.</span>), or (by others)
+Demetrius and Alexander; in favour of Alexander as the
+&ldquo;youth&rdquo; it may be said that he was of obscure origin, was at
+first popular, and was later abandoned by his friends. Such
+identifications, however, do not fix the date of the book precisely;
+the author may have referred to events that happened
+before his time. The reign of Herod, a period of despotism and
+terror, and of strife between Jewish religious parties, is preferred
+by some scholars (Grätz, Cheyne and others) as best answering
+to the social situation depicted in the book, while still others
+(as Renan) decide for the reign of Alexander Jannaeus (104-78
+<span class="scs">B.C.</span>). The data are not numerous and distinct enough to
+settle the question beyond determining general limits: for
+reasons given above the book can hardly have been composed
+before about 200 <span class="scs">B.C.</span>, and if, as is probable, a Septuagint translation
+of it was made (though the present Septuagint text
+shows the influence of Aquila), it is to be put earlier than 50 <span class="scs">B.C.</span>
+Probably also, its different parts are of different dates.</p>
+
+<p>Of the author nothing is known beyond the obvious fact that
+he was a man of wide observation and philosophic thought, of
+the Sadducean type in religion, but non-Jewish in his attitude
+toward life. He was, doubtless, a man of high standing, but
+neither a king nor a high-priest, certainly not the apostate priest
+Alcimus (1 Macc. vii. ix.); nor was he necessarily a physician&mdash;there
+are no details in ch. xii. or elsewhere that any man of good
+intelligence might not know. The book is written in prose, some
+of which is rhythmical, with bits of verse here and there: thus
+i. 2-11 is balanced prose, 12-14 plain prose, 15 a couplet, i. 16-ii.
+25 simple prose, vii. contains a number of poetical aphorisms,
+and so on. Some of the verses are apparently from the author,
+some from editors.</p>
+
+<p>The fortunes of the book are not known in detail, but it is clear
+that its merciless criticism of life and its literary charm made it
+popular, while its scepticism excited the apprehensions of pious
+conservatives. Possibly the <i>Wisdom of Solomon</i> (<i>c.</i> 50 <span class="scs">B.C.</span>) was
+written partly as a reply to it. The claim of sacredness made for
+it was warmly contested by some Jewish scholars. In spite of
+the relief afforded by orthodox additions, it was urged that
+its Epicurean sentiments contradicted the Torah and favoured
+heresy. Finally, by some process of reasoning not fully recorded,
+the difficulties were set aside and the book was received into the
+sacred canon; Jerome (on Eccl. xii. 13, 14) declares that the
+decisive fact was the orthodox statement at the end of the
+book: the one important thing is to fear God and keep His
+commandments. The probability is that the book had received
+the stamp of popular approbation before the end of the 1st
+century of our era, and the leading men did not dare to reject it.
+It is not certain that it is quoted in the New Testament, but it
+appears to be included in Josephus&rsquo; list of sacred books.</p>
+
+<div class="condensed">
+<p><span class="sc">Literature.</span>&mdash;For the older works see Zöckler (in Lange&rsquo;s <i>Comm.</i>);
+for Jewish commentaries see Zedner, <i>Cat. of Heb. books in Libry. of
+Brit. Mus.</i> (1867), and for the history of the interpretations, C.D.
+Ginsburg, <i>Coheleth</i> (1861). <i>Introductions</i> of A. Kuenen, S.R. Driver,
+Cornhill, König. Articles in Herzog-Hauck, <i>Realencykl.</i> (by P.
+Kleinert); Hastings, <i>Dict. Bible</i> (by A.S. Peake); T.K. Cheyne,
+<span class="pagenum"><a name="page853" id="page853"></a>853</span>
+<i>Encycl. Bibl.</i> (by A.B. Davidson); <i>Jew. Encycl.</i> (by D.S. Margoliouth).
+Commentaries: F. Hitzig (1847); C.D. Ginsburg (1861); H. Grätz
+(1871); Tyler (1874); Delitzsch (1875); E.H. Plumptre (1881);
+C.H.H. Wright (1883); Nowack, revision of Hitzig (1883); Volck
+(in Strack u. Zöckler&rsquo;s <i>Kurzgef. Komm.</i>, 1889); Wildeboer (in
+Marti&rsquo;s <i>Kurzer Hand-Comm.</i>, 1898); C. Siegfried (in W. Nowack&rsquo;s
+<i>Handkomm.</i>, 1898); Oort (in <i>De Oude Test.</i>, 1899). Other works:
+C. Taylor, <i>Dirge of Koh.</i> (1874); Wünsche, <i>Midrash</i> on Koh. (in
+his <i>Biblioth. rabbin.</i>, 1880); E. Renan, <i>L&rsquo;Ecclésiaste</i> (1882); Bickell,
+<i>Der Prediger</i> (1884) and <i>Kohel.-Untersuchungen</i> (1886; Engl. by
+E.J. Dillon, <i>Sceptics of Old Test.</i>, 1895); Schiffer, <i>Das Buch Koh.
+nach d. Auffass. d. Weisen d. Talmuds</i>, &amp;c. (1884); A. Palm, <i>Qoh. u.
+d. nach-aristotel. Philosophie</i> (1885) and <i>Die Qoh.-Lit.</i> (1886);
+E. Pfleiderer, <i>Die Phil. d. Heraklit</i>, &amp;c. (1886); Cheyne, <i>Job and
+Solomon</i> (1887) and <i>Jew. Relig. Life</i>, &amp;c. (1898); W. Euringer,
+<i>Der Masorahtext d. Koh.</i> (1890); W.T. Davison, <i>Wisdom-Lit. of Old
+Test.</i> (1894); H. Winckler, in his <i>Altorient. Forschungen</i> (1898);
+J.F. Genung, <i>Words of Koh.</i> (Boston, Mass., 1904); P. Haupt,
+<i>Ecclesiastes</i> (Baltimore, 1905). The rabbinical discussions of the
+book are mentioned in <i>Shabbath</i>, 30b; <i>Megilla</i>, 7a; <i>Eduyoth</i>, v. 3;
+<i>Mishna Yadaim</i>, iii. 5, iv. 6; <i>Midrash Koheleth</i> (on xi. 9), <i>Aboth
+d&rsquo; Rab. Nathan</i>, i.</p>
+</div>
+<div class="author">(C. H. T.*)</div>
+
+<hr class="foot" /> <div class="note">
+
+<p><a name="ft1g" id="ft1g" href="#fa1g"><span class="fn">1</span></a> The Hebrew has the definite article, &ldquo;the whole,&rdquo; <span class="grk" title="to pan">&#964;&#8056; &#960;&#8118;&#957;</span>.</p>
+
+<p><a name="ft2g" id="ft2g" href="#fa2g"><span class="fn">2</span></a> In fact, he suggests, a curse, as in Gen. iii. 17-19, though with
+a wider sweep than that passage has in mind.</p>
+
+<p><a name="ft3g" id="ft3g" href="#fa3g"><span class="fn">3</span></a> The text has &ldquo;folly,&rdquo; but the parallelism and v. 7 point to social,
+not intellectual, conditions, and a slight change (<span title="misken">&#1502;&#1505;&#1499;&#1503;</span> for <span title="haskel">&#1492;&#1505;&#1499;&#1500;</span>) gives
+the sense &ldquo;poor.&rdquo;</p>
+
+<p><a name="ft4g" id="ft4g" href="#fa4g"><span class="fn">4</span></a> The Septuagint has less well: &ldquo;They (the wicked) are praised
+in the city.&rdquo;</p>
+
+<p><a name="ft5g" id="ft5g" href="#fa5g"><span class="fn">5</span></a> The clause is obscure; literally &ldquo;he (or, one) rises at (?) the
+voice of the bird,&rdquo; usually understood to refer to the old man&rsquo;s
+inability to sleep in the morning; but this is not a universal trait
+of old age, and besides, a reference to affairs in the house is to be
+expected; the Hebrew construction also is of doubtful correctness.
+A change of the Hebrew text seems necessary; possibly we should
+read <span title="ishpal kol">&#1497;&#1513;&#1508;&#1500; &#1511;&#1493;&#1500;</span>, &ldquo;low is the voice,&rdquo; instead of <span title="yakum lekol">&#1497;&#1511;&#1493;&#1501; &#1500;&#1511;&#1493;&#1500;</span> &ldquo;he rises up at
+the voice.&rdquo;</p>
+
+<p><a name="ft6g" id="ft6g" href="#fa6g"><span class="fn">6</span></a> The second is perhaps to be read: &ldquo;the caper-berry blooms&rdquo;
+(white hair); usually &ldquo;the caper-berry loses its appetizing
+power&rdquo;; Eng. Auth. Vers. &ldquo;desire shall fail.&rdquo; For the meaning
+of the word <i>abyona</i> (&ldquo;caper-berry,&rdquo; not &ldquo;desire&rdquo; or &ldquo;poverty&rdquo;),
+see art. by G.F. Moore in <i>Journ. of Bibl. Lit.</i> x. 1 (Boston, Mass.,
+1891).</p>
+
+<p><a name="ft7g" id="ft7g" href="#fa7g"><span class="fn">7</span></a> This is the Talmudic understanding of the Hebrew expression
+(Jerus. Sanhed. 10, 28a, cf. Sanhed. 12a; see Ecclus. xxxix. 2).
+There is no good authority for the renderings &ldquo;collectors of maxims,&rdquo;
+&ldquo;collections of maxims.&rdquo;</p>
+
+<p><a name="ft8g" id="ft8g" href="#fa8g"><span class="fn">8</span></a> It is not certain that the codex form was in use in Palestine
+or in Egypt as early as the 2nd or the 1st century <span class="scs">B.C.</span></p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIASTICAL COMMISSIONERS,<a name="ar117" id="ar117"></a></span> in England, a body
+corporate, whose full title is &ldquo;Ecclesiastical and Church Estates
+Commissioners for England,&rdquo; invested with very important
+powers, under the operation of which extensive changes have been
+made in the distribution of the revenues of the Established
+Church. Their appointment was one of the results of the vigorous
+movements for the reform of public institutions which followed
+the Reform Act of 1832. In 1835 two commissions were appointed
+&ldquo;to consider the state of the several dioceses of England and
+Wales, with reference to the amount of their revenues and the
+more equal distribution of episcopal duties, and the prevention
+of the necessity of attaching by commendam to bishoprics
+certain benefices with cure of souls; and to consider also the
+state of the several cathedral and collegiate churches in England
+and Wales, with a view to the suggestion of such measures as
+might render them conducive to the efficiency of the established
+church, and to provide for the best mode of providing for the cure
+of souls, with special reference to the residence of the clergy on
+their respective benefices.&rdquo; And it was enacted by an act of
+1835 that during the existence of the commission the profits of
+dignities and benefices without cure of souls becoming vacant
+should be paid over to the treasurer of Queen Anne&rsquo;s Bounty.
+In consequence of the recommendation of these commissioners,
+a permanent commission was appointed by the Ecclesiastical
+Commissioners Act 1836 for the purpose of preparing and laying
+before the king in council such schemes as should appear to them
+to be best adapted for carrying into effect the alterations suggested
+in the report of the original commission and recited in the act.
+The new commission was constituted a corporation with power
+to purchase and hold lands for the purposes of the act, notwithstanding
+the statutes of mortmain. The first members of the
+commission were the two archbishops and three bishops, the lord
+chancellor and the principal officers of state, and three laymen
+named in the act.</p>
+
+<p>The constitution of the commission was amended by the
+Ecclesiastical Commissioners Act 1840 and subsequent acts, and
+now consists of the two archbishops, all the bishops, the deans of
+Canterbury, St Paul&rsquo;s and Westminster, the lord chancellor, the
+lord president of the council, the first lord of the treasury, the
+chancellor of the exchequer, the home secretary, the lord chief
+justice, the master of the rolls, two judges of the admiralty
+division, and certain laymen appointed by the crown and by the
+archbishop of Canterbury. The lay commissioners are required
+to be &ldquo;members of the Church of England, and to subscribe a
+declaration to that effect.&rdquo; The crown also appoints two laymen
+as church estates commissioners, and the archbishop of Canterbury
+one. These three are the joint treasurers of the commission,
+and constitute, along with two members appointed by the commission,
+the church estates committee, charged with all business
+relating to the sale, purchase, exchange, letting or management
+of any lands, tithes or hereditaments. The commission has
+power to make inquiries and examine witnesses on oath. Five
+commissioners are a quorum for the transaction of business,
+provided two of them are church estates commissioners; two
+ecclesiastical commissioners at least must be present at any
+proceeding under the common seal, and if only two are present
+they can demand its postponement to a subsequent meeting.
+The schemes of the commission having, after due notice to
+persons affected thereby, been laid before the king in council, may
+be ratified by orders, specifying the times when they shall take
+effect, and such orders when published in the <i>London Gazette</i>
+have the same force and effect as acts of parliament.</p>
+
+<div class="condensed">
+<p>The recommendations of the commission recited in the act of
+1836 are too numerous to be given here. They include an extensive
+rearrangement of the dioceses, equalization of episcopal income,
+providing residences, &amp;c. By the act of 1840 the fourth report of the
+original commissioners, dealing chiefly with cathedral and collegiate
+churches, was carried into effect, a large number of canonries being
+suspended, and sinecure benefices and dignities suppressed.</p>
+
+<p>The emoluments of these suppressed or suspended offices, and the
+surplus income of the episcopal sees, constitute the fund at the
+disposal of the commissioners. By an act of 1860, on the avoidance
+of any bishopric or archbishopric, all the land and emoluments of
+the see, except the patronage and lands attached to houses of
+residence, become, by order in council, vested in the commissioners,
+who may, however, reassign to the see so much of the land as may
+be sufficient to secure the net annual income named for it by statute or
+order. All the profits and emoluments of the suspended canonries, &amp;c.,
+pass over to the commissioners, as well as the separate estates of those
+deaneries and canonries which are not suspended. Out of this fund
+the expenses of the commission are to be paid, and the residue is to
+be devoted to increasing the efficiency of the church by the augmentation
+of the smaller bishoprics and of poor livings, the endowment
+of new churches, and employment of additional ministers.</p>
+
+<p>The substitution of one central corporation for the many local and
+independent corporations of the church, so far at least as the management
+of property is concerned, was a constitutional change of great
+importance, and the effect of it undoubtedly was to correct the
+anomalous distribution of ecclesiastical revenues by equalizing
+incomes and abolishing sinecures. At the same time it was regarded
+as having made a serious breach in the legal theory of ecclesiastical
+property. &ldquo;The important principle,&rdquo; says Cripps, &ldquo;on which the
+inviolability of the church establishment depends, that the church
+generally possesses no property as a corporation, or which is applicable
+to general purposes, but that such particular ecclesiastical
+corporation, whether aggregate or sole, has its property separate,
+distinct and inalienable, according to the intention of the original
+endowment, was given up without an effort to defend it&rdquo; (<i>Law
+Relating to the Church and Clergy</i>, p. 46).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIASTICAL JURISDICTION.<a name="ar118" id="ar118"></a></span> This phrase in its primary
+sense imports not jurisdiction over ecclesiastics, but jurisdiction
+exercised by ecclesiastics over other ecclesiastics and over
+the laity. &ldquo;Jurisdiction&rdquo; is a word borrowed from the jurists
+which has acquired a wide extension in theology, wherein, for
+example, it is frequently used in contradistinction to &ldquo;order,&rdquo;
+to express the right to administer sacraments as something
+superadded to the <i>power</i> to celebrate them. So it is used to
+express the territorial or other limits of ecclesiastical, executive
+or legislative authority. Here it is used, in the limited sense
+defined by an American Court, as &ldquo;the authority by which
+judicial officers take cognizance of and decide causes.&rdquo;</p>
+
+<p>Such authority in the minds of lay Roman lawyers who first
+used this word &ldquo;jurisdiction&rdquo; was essentially temporal in its
+origin and in its sphere. The Christian Church transferred
+the notion to the spiritual domain as part of
+<span class="sidenote">Origin of ecclesiastical jurisdiction.</span>
+the general idea of a Kingdom of God correlative, on
+the spiritual side of man upon earth, to the powers,
+also ordained of God, who had dominion over his temporal
+estate (see <span class="sc"><a href="#artlinks">Canon Law</a></span>). As the Church in the earliest
+ages had executive and legislative power in its own spiritual
+sphere, so also it had &ldquo;judicial officers,&rdquo; &ldquo;taking cognizance of
+and deciding causes.&rdquo; Only before its union with the State, its
+power in this direction, as in others, was merely over the spirits
+of men. Coercive temporal authority over their bodies or estates
+could only be given by concession from the temporal prince.
+Moreover, even spiritual authority over members of the Church,
+<i>i.e.</i> baptized persons, could not be exclusively claimed as <i>of right</i>
+by the Church tribunals, if the subject matter of the cause were
+purely temporal. On the other hand, it is clear that <i>all</i> the
+faithful were subject to these courts (when acting within their
+own sphere), and that, in the earliest times, no distinction was
+made in this respect between clergy and laity.</p>
+
+<p>The fundamental principle of ecclesiastical jurisdiction with its
+<span class="pagenum"><a name="page854" id="page854"></a>854</span>
+&ldquo;sanction&rdquo; of excommunication will be found in Christ&rsquo;s words
+in Matt. xviii. 15-18. A very early example of criminal spiritual
+jurisdiction exercised by St Paul is found in the case of the incestuous
+Corinthian (1 Cor. v.). We find later the same apostle
+exercising like jurisdiction in the cause of Hymenaeus and
+Alexander (1 Tim. i. 20). After the time of the Apostles, we
+find this criminal jurisdiction exercised by the bishops individually
+over their respective &ldquo;subjects&rdquo;&mdash;doubtless with the advice
+of their presbyters according to the precept of St Ignatius
+(<i>c.</i> 110). As neighbouring dioceses coalesced into &ldquo;provinces&rdquo;
+and provinces into larger districts (corresponding to the civil
+&ldquo;dioceses&rdquo; of the later Roman Empire), the provincial synods of
+bishops and the synods of the larger districts acquired a criminal
+jurisdiction, still purely spiritual, of their own. At first this was
+&ldquo;original&rdquo; and mainly (although not exclusively) over bishops
+(of the province or larger district). The beginnings of an
+appellate jurisdiction in the cases of clerics and laymen may be
+traced before the conversion of the Empire. The bishop over
+whom the synod of neighbouring bishops had exercised jurisdiction
+had no formal right of appeal; but sometimes bishops in
+other parts of the Church would refuse to acknowledge the local
+synodical sentence and would communicate with a bishop whom
+they deemed unjustly deposed. The theory, as expressed in
+legal phrase by St Cyprian in the 3rd century, was that the
+apostolic power of delegated sovereignty from the Lord, alike
+legislative and judicial, was held in joint-tenancy by the whole
+body of Catholic bishops. In both capacities, however, a certain
+undefined pre-eminence was conceded to the occupants of
+&ldquo;Apostolic&rdquo; sees, <i>i.e.</i> sees traditionally founded by Apostles, or
+of sees with a special secular position.</p>
+
+<p>Even before the edict of Milan, at least as early as the latter
+half of the 3rd century, the spiritual sentences of deposition
+from office had sometimes indirect temporal consequences
+recognized by the secular courts. The classical example is the
+case of Paul of Samosata, bishop of Antioch. It would seem
+that, in the intervals of persecution, some rights of property
+were recognized in the Christian Church and its officers; although
+the Church was an illegal society. After some previous abortive
+trials, Paul of Samosata was deposed and excommunicated, in
+269, by a great synod of the Antiochene district. Paul, notwithstanding
+his deposition, kept possession of the episcopal residence.
+The local church sought recovery of it before the tribunals of
+the Empire. The judicial authorities requested a rescript from
+the emperor Aurelian for the decision of the cause. Aurelian
+referred the matter to the bishop of Rome and the bishops of
+Italy, who gave their award in favour of the Antiochene Church.</p>
+
+<p>Side by side with this which we may call criminal jurisdiction&mdash;none
+the less real or coercive because its sanctions were purely
+spiritual&mdash;there grew up a quasi-jurisdiction in causes
+entirely temporal, based upon the free consent of the
+<span class="sidenote">Temporal Jurisdiction of the Church.</span>
+parties to accept the arbitration of the bishop. This
+system had also its roots in the New Testament (see
+Matt, xviii. 15-17 and 1 Cor. vi. 1-8). In the matter of
+criminal jurisdiction we paused for a moment at the edict of
+Milan; but we may at once trace this second or civil branch of
+episcopal judicature or quasi-judicature down as far as the reign
+of Charlemagne, when it underwent a fundamental change, and
+became, if <i>either</i> litigant once chose, no longer a matter of
+consent but of right.</p>
+
+<p>Constantine decreed that judgment in causes might be passed
+by bishops when litigants preferred their adjudication to that
+of the secular courts (see his epistle to the Numidian bishops and
+<i>Cod. Theodos. Tit. de Episcopis</i>). The episcopal judgment was
+to be equivalent to that of the emperor and irreversible, and the
+civil authorities were to see to its execution. Saints Ambrose
+and Augustine both spent days in deciding temporal causes.
+Honorius, in the West, at the end of the 4th century, made a
+constitution providing that if any desired to litigate before the
+bishops they should not be forbidden, but that in civil matters
+the prelates should render judgment in the manner of arbitrators
+by consent (<i>Cod.</i> 1, <i>Tit.</i> iv.). Where the faithful had had recourse
+to the bishop, no appeal was to be allowed, and the judges were
+to command execution of the episcopal decree. A quarter of a
+century later, however, Valentinian III. in the West expressly
+provided that bishops were not to be permitted to be judges
+(that is, of course, in temporal causes), save by the consent of the
+parties. This legislation was, substantially, adopted by Justinian.</p>
+
+<p>On the revival of the Western Empire, however, Charlemagne,
+in the beginning of the 9th century, under the mistaken belief
+that he was following the authority of Constantine I. and
+Theodosius I., took a great step forward, by which the bishop
+ceased to be a mere legally indicated arbitrator by consent in
+secular causes, and became a real judge. By a capitulary he
+provided that either litigant, without the consent of the other
+party, and not only at the beginning of a suit but at any time
+during its continuance, might take the cause from lay cognizance
+and transfer it to the bishop&rsquo;s tribunal. He re-enacted the
+prohibition of appeal.</p>
+
+<p>It should be remembered that, from the latter part of the
+3rd century, the leading bishops had generally been trained in
+secular learning. St Cyprian, St Ambrose and St Augustine, St
+Paulinus of Nola and St John Chrysostom had practised law
+as teachers or advocates. St Ambrose and St Paulinus had even
+held high administrative and judicial offices.</p>
+
+<p>To return to the evolution of ecclesiastical jurisdiction from
+the time of Constantine. With the &ldquo;Nicene period&rdquo; came a
+great development on the criminal side. A system
+begins to be formed, and the secular arm supports
+<span class="sidenote">Roman empire from Constantine.</span>
+the decrees of the Church. The first trace of system
+is in the limited right of appeal given by the first
+oecumenical council of Nicaea and its provision that episcopal
+sentences or those of provincial synods on appeal were to be
+recognized throughout the world. The fifth canon provides
+that those, whether clerics or laymen, who are cut off from communion
+in any particular province are not to be admitted
+thereto elsewhere. Still examination must be had whether
+persons have been expelled from the congregation by any
+episcopal small-mindedness (<span class="grk" title="mikropsychia">&#956;&#953;&#954;&#961;&#959;&#968;&#965;&#967;&#943;&#945;</span>), or contentious spirit,
+or such-like harshness (<span class="grk" title="aêdia">&#7936;&#951;&#948;&#943;&#945;</span>). That this may be conveniently
+inquired into, synods are to be held, three in every year, in each
+province, and questions of this kind examined. There is to be no
+&ldquo;stay of execution&rdquo;; the episcopal sentence is to prevail until
+the provincial synod otherwise decide. It will be noticed that
+as yet no provision is made for appeals by <i>bishops</i> from provincial
+synods sitting in first instance.</p>
+
+<p>The edicts of Milan had only admitted the Christian Church
+among the number of lawful religions; but the tendency (except
+in the time of Julian) was towards making it the only lawful
+religion. Hence the practice, immediately after Nicaea I., of
+superadding banishment by the emperor to synodical condemnation.
+The dogmatic decrees of Nicaea I. were at once enforced
+in this temporal manner. On the other hand, the Arian reaction
+at court worked its objects (see Pusey, <i>Councils of the Church</i>)
+by using the criminal spiritual jurisdiction of synods against the
+Catholics&mdash;often packing the synods for the purpose. The acts
+of councils of this age are full of the trials of bishops not only for
+heresy but for immorality and common law crimes. The accusations
+are frequently unfounded; but the trials are already
+conducted in a certain regular forensic form. The secular
+authorities follow the precedent of Nicaea I. and intervene to
+supplement the spiritual sentence by administrative penalties.
+Sometimes an imperial officer of high rank (as, <i>e.g.</i> a &ldquo;count&rdquo;)
+is present at the synod, as an assessor to maintain order and
+advise upon points of procedure. Leading examples may be
+found in the various prosecutions of St Athanasius, in whose
+case also there is the germ of an appeal, <i>tanquam ab abusu</i>. It
+has been contended that, according to later and more formulated
+jurisprudence, such an appeal would have lain, since the trial
+at Tyre was not concerned with purely spiritual matters (see
+the case in Hefele, <i>Councils</i>, in loc.).</p>
+
+<p>The trial of St Athanasius led to extensions of the right of
+appeal. This was favoured by the development of the greater
+sees into positions of great administrative dignity, shortly to
+be called &ldquo;patriarchal.&rdquo; A synod was held at Rome, attended
+<span class="pagenum"><a name="page855" id="page855"></a>855</span>
+by bishops from various regions, which reversed the original
+judgment of the synod of Tyre which had condemned Athanasius.
+A much larger synod at Antioch, gathered only from the East,
+on the other hand, confirmed that judgment. This last synod
+did something to systematize the criminal procedure of the
+Church, and its legislation has been always received.</p>
+
+<p>This legislation marks another step forward. Deposition of
+a bishop by a synod, or of a priest or deacon by his bishop, is to
+take effect even pending an appeal, and a cleric continuing his
+functions after sentence in first instance is to lose all right of
+appeal. The appeal given by Nicaea I. to clerics and laymen
+from episcopal excommunications is extended. The synod may
+restore them if convinced of the justice of their cause (and not
+merely in cases of <span class="grk" title="aêdia">&#7936;&#951;&#948;&#943;&#945;</span>). A bishop may appeal to a great
+assembly of bishops. Any bishop, priest or deacon &ldquo;importuning&rdquo;
+the emperor, instead of exerting his right of appeal to
+synods, is to lose all right of appeal and never to be restored or
+pardoned. If a provincial synod be divided as to the guilt of a
+bishop, the metropolitan is to convene bishops from the neighbouring
+provinces to decide the cause jointly with the bishops of
+the original province.</p>
+
+<p>A few years later, in 347, the council of Sardica, a council of
+practically the whole West save Africa, reversed Tyre and
+acquitted St Athanasius after a full judicial inquiry. This
+council endeavoured to set up a system of appeals in the case of
+bishops, in which the see of Rome was made to play a great part.
+&ldquo;Out of honour to the memory of St Peter,&rdquo; a condemned
+bishop may ask the intervention of Rome. If this be done, the
+synod of first instance is to send letters to Julius, bishop of
+Rome. If that prelate think the cause should be heard again,
+he is to appoint judges; if otherwise, the original judgment
+is to be confirmed. Pending appeal, the appellant&rsquo;s see is not
+to be filled up. The judges appointed by the bishop of Rome
+to hear the appeal are to be from the neighbouring provinces.
+The appellant may, however, request that bishop to send priests
+from his side to sit with the synod of appeal. If such priests are
+sent, they are to preside in the court of appeal. These canons
+were always repudiated in the East, and when, sixty years
+afterwards, they were, for the first time, heard of in Africa, they
+were repudiated there also.</p>
+
+<p>A rescript of Gratian in 378 empowered the bishop of Rome
+to judge bishops with the assistance of six or seven other bishops
+or, in the case of a metropolitan, of fifteen comprovincial bishops.
+A bishop refusing to come to Rome was to be brought there by
+the civil power. The rescript, however, was not incorporated in
+the Codes and perhaps was only a temporary measure.</p>
+
+<p>The tendency to give pre-eminence to Rome appears again
+in an imperial letter to St Flavian, who, in the judgment of the
+East, was bishop of Antioch, but who was rejected by the West
+and Egypt, summoning him to Rome to be there judged by the
+bishops of the imperial city&mdash;a summons which St Flavian did
+not obey (Tillemont, <i>Mém. Ecc.</i>). In Africa in the beginning of
+the 5th century Apiarius, a priest who had been deposed by the
+bishop of Sicca for immorality, and whose deposition had been
+affirmed by the &ldquo;provincial synod,&rdquo; instead of further appealing
+to a general synod of Africa, carried his appeal to Pope Zosimus.
+The pope received the appeal, absolved him and restored him to
+the rank of priest, and sent a bishop and two priests as legates
+to Africa with instructions to them to hear the cause of Apiarius
+anew and for execution of their sentence to crave the prefect&rsquo;s
+aid; moreover, they were to summon the bishop of Sicca to
+Rome and to excommunicate him, unless he should amend
+those things which the legates deemed wrong. The upshot of a
+long conflict was that the papal claim to entertain appeals from
+Africa by priests and deacons was rejected by the African
+bishops, who in their final synodical epistle also repudiate in
+terms any right of appeal by African <i>bishops</i> to &ldquo;parts beyond
+the seas&rdquo; (see Hefele, <i>Councils</i>, bk. viii.).</p>
+
+<p>The story of the administrative development of the Church in
+the 5th century is mainly the story of the final emergence and
+constitution of the great &ldquo;patriarchates,&rdquo; as authorities superior
+to metropolitans and provincial synods. In consequence of the
+occupants of the thrones of Constantinople and Alexandria
+falling successively into opposite heresies, the question arose how
+&ldquo;patriarchs&rdquo; were to be judged. In both cases, as it seems, an
+attempt was made by the bishop of Rome to depose the erring
+patriarch by his authority as primate of Christendom, acting in
+concert with a Western synod. In both cases, apparently, an
+oecumenical synod ignored the Roman deposition and judged the
+alleged offences of the respective patriarchs in first and last
+instance. The third and fourth oecumenical synods (Ephesus,
+431; Chalcedon, 451) were primarily tribunals for the trials of
+Nestorius and Dioscorus; it was secondarily that they became
+organs of the universal episcopate for the definition of the faith,
+or legislative assemblies for the enactment of canons. Nothing
+is more remarkable than their minute care as to observance of
+rules of procedure. In both cases, imperial assessors were
+appointed. At Ephesus the Count Candidian was commissioned
+to maintain order, but took little part in the proceedings. At
+Chalcedon, on the other hand, the imperial commissioners decided
+points of order, kept the synod to the question, took the votes
+and adjourned the court. But the synod alone judged and
+pronounced sentence. No oecumenical synod has tried a
+patriarch of Old Rome while yet in the flesh. The fifth oecumenical
+council came nearest to so doing, in the case of Vigilius.
+That pope, although in Constantinople, refused to attend the
+sittings of the council. He was cited three times, in the canonical
+manner, and upon not appearing was threatened in the third
+session with anathema (Hefele, <i>Councils</i>, sect. 268 <i>ad fin.</i>). He
+was not, however, charged with direct heresy, as were Nestorius
+and Dioscorus, and the synod seems to have hesitated to deal
+stringently with the primate of Christendom. In the seventh
+session it accepted the suggestion of Justinian, merely to order
+the name of Vigilius to be removed from the liturgical prayers,
+at the same time expressing its desire to maintain unity with the
+see of Old Rome (Hefele, sect. 273). After the council, Justinian
+banished the pope to Egypt, and afterwards to an island, until
+he accepted the council, which he ultimately did (<i>ib.</i> 276). The
+sixth oecumenical synod decreed that the dead pope Honorius
+should be &ldquo;cast out from the holy Catholic Church of God&rdquo;
+and anathematized, a sentence approved by the reigning pope
+Leo II. and affirmed by the seventh oecumenical synod in 787.</p>
+
+<p>The constitution of the patriarchal system resulted in the
+recognition of a certain right of appeal to Rome from the larger
+part of the West. Britain remained outside that jurisdiction,
+the Celtic churches of the British islands, after those islands
+were abandoned by the Empire, pursuing a course of their own.
+In the East, Constantinople, from its principality, acquired
+special administrative pre-eminence, naturally followed, as in
+the case of &ldquo;old Rome,&rdquo; by judicial pre-eminence. An example
+of this is found in the ninth canon of Chalcedon, which also
+illustrates the enforcement upon a clerical plaintiff in dispute
+with a brother cleric of that recourse to the arbitration of their
+ecclesiastical superior already mentioned. The canon provides
+that any clerk having a complaint against another clerk must
+not pass by his own bishop and turn to secular tribunals, but
+first lay bare his cause before him, so that by the sentence of the
+bishop himself the dispute may be settled by arbitrators acceptable
+to both parties. Any one acting against these provisions
+shall be subject to canonical penalties. If any clerk have a
+complaint against his own bishop, he shall have his cause adjudicated
+upon by the synod of the province. But if a bishop
+or clerk have a difference with the metropolitan of his province
+let him bring it before the exarch of the &ldquo;diocese&rdquo; (<i>i.e.</i> the
+larger district answering to the civil &ldquo;diocese&rdquo;), or before the
+royal see of Constantinople, who shall do justice upon it. An
+&ldquo;exarch&rdquo; means properly a superior metropolitan having several
+provinces under him. In the next century Justinian (<i>Nov.</i> 123,
+c. 22) put the other patriarchates on the same footing as Constantinople.
+In c. 21 he gives either plaintiff or defendant an
+appeal within ten days to the secular judge of the locality from
+the bishop&rsquo;s judgment. If there be no appeal, that judge is to
+give execution to the episcopal award. The growth of a special
+&ldquo;original&rdquo; jurisdiction at Constantinople, which perhaps
+<span class="pagenum"><a name="page856" id="page856"></a>856</span>
+developed earlier than the corresponding institution at Rome,
+may be traced to the fact that bishops from all parts were
+constantly in Constantinople. The bishop of Constantinople,
+even before he became properly &ldquo;patriarch,&rdquo; would often
+assemble a synod from these visiting bishops, which acquired
+the technical name of <span class="grk" title="synodos endêmousa">&#963;&#973;&#957;&#959;&#948;&#959;&#962; &#7952;&#957;&#948;&#951;&#956;&#959;&#8166;&#963;&#945;</span>, the synod of sojourners.
+This synod frequently decided questions belonging to other
+patriarchates.</p>
+
+<p>The criminal jurisdiction thus exercised was generally speaking
+unlimited. It must be remembered that the <i>forum externum</i> of
+the ecclesiastical jurisdiction, in the sense in which we now use
+the phrase, of a judge deciding causes, was not then clearly
+marked off from the <i>forum internum</i>, or what afterwards came
+to be called the &ldquo;tribunal of penance&rdquo; (see Van Espen, <i>Jus ecc.
+univ.</i> pars iii. tit. iv. c. 1). Ecclesiastical proceedings by way
+of prosecution are called &ldquo;criminal,&rdquo; but they are primarily
+<i>pro salute animae</i>; whereas temporal criminal proceedings are
+primarily for the protection of the state and its citizens. Hence
+a Christian might be first punished in the civil courts and then
+put to public penance by the ecclesiastical jurisdiction, or vice
+versa: an apparently double system of punishment which the
+medieval Church, when the <i>forum externum</i> had become quite
+separated from the <i>forum internum</i>, sometimes repudiated (see
+Maitland, <i>English Canon Law</i>, 138, 139, 144).</p>
+
+<p>Theodosius began the system of giving secular authority to
+Church tribunals. Thus, in 376, L. 23 <i>Cod. Theodos. de. Episcopis</i>,
+&amp;c., subjected clerics for small offences pertaining to the observances
+of religion to bishops and synods. In 399, L. 1 <i>Cod. de
+Religione</i> provides that, when it is a matter of religion, it beseems
+the bishop to judge. A rescript of Constantius, in 355, inserted
+in <i>Cod. Theod.</i> lxii. <i>de Epis. Ecc. et Cler.</i>, excluded bishops
+from accusations before secular judges and commanded such
+accusations to be speedily brought before the tribunal of other
+bishops. This law was probably only intended to be of a
+temporary character. Then comes the law of Gratian already
+noticed. Then, in 399, a law of Honorius (<i>Cod. Theod.</i> L. 1 <i>de
+Religione</i>): &ldquo;As often as it concerns religion, it is meet that the
+bishops should judge, but other causes which belong to ordinary
+jurisdiction or to public law are to be heard in the ordinary courts
+(<i>legibus oportet audiri</i>).&rdquo; L. 3 <i>de Epis. Jud.</i>, at the end of the
+Theodosian Code, seems spurious (see the comment of Gothofredus
+in loco). But a constitution of Honorius in 412 (<i>Cod.
+Theod.</i> L. xli. <i>de Epis. Ecc. et Cler.</i>) provides that clerks are not
+to be accused except before the bishop. Bishops, priests,
+deacons, and every other &ldquo;minister of the Christian law&rdquo; of
+inferior degree, are taken from secular jurisdiction in criminal
+cases. The words are quite general; but it has been contended
+that they apply only to crimes of an ecclesiastical character (see
+Gothofredus in loc.; Van Espen, pars iii. tit. iii. c. 1, 10). In
+425 a constitution of Theodosius II. provides that a recent
+decree of the usurper John should be disregarded and that clerks
+whom he had brought before secular judges should be reserved
+for the episcopal jurisdictions, &ldquo;since it is not lawful to subject
+the ministers of the divine office to the arbitrament of temporal
+powers.&rdquo; Justinian has a clearer perception of the demarcation
+between the spheres of spiritual and temporal law. The 83rd
+Novell provides that if the offence be ecclesiastical, needing
+ecclesiastical correction, the bishop shall take cognizance of it.
+The 123rd Novell (<i>c.</i> 21) provides that if a clerk be accused of
+a secular crime he shall be accused before his bishop, who may
+depose him from his office and order, and then the competent
+judge may take him and deal with him according to the laws.
+If the prosecutor have first brought him before the civil judge,
+the evidence is to be sent to the bishop, and the latter, if he thinks
+the crime has been committed, may deprive him of his office
+and order, and the judge shall apply to him the proper legal
+punishment. But if the bishop think the evidence insufficient,
+the affair shall be referred to the emperor, by way of appeal both
+from bishop and judge. If the cause be ecclesiastical, the civil
+judges are to take no part in the inquiry. The law includes with
+clerics, monks, deaconesses, nuns, ascetics; and the word
+&ldquo;clerics&rdquo; covered persons in minor orders, down to doorkeepers.
+It will be noticed that Justinian supposes that the prosecutor
+may begin the proceedings before the civil judge. A constitution
+of Alexius Comnenus I. seems to send him to the special forum of
+the accused.</p>
+
+<p>Certain enactments of later Saxon times in England have been
+sometimes spoken of as though they united together the temporal
+and spiritual jurisdictions into one mixed tribunal
+deriving its authority from the State. In the latter
+<span class="sidenote">Anglo-Saxon courts.</span>
+part of the 10th century, laws of Edgar provided that
+the bishop should be at the county court and also the
+alderman, and that there each of them should put in use both
+God&rsquo;s laws and the world&rsquo;s law (Johnson&rsquo;s <i>English Canons</i>, i.
+411). This probably was, as Johnson suggests, that the bishop
+might enforce secular laws by ecclesiastical censure and the
+alderman ecclesiastical laws with secular punishment. But the
+two jurisdictions were kept separate; for by another law of
+Edgar (<i>Leges Edg.</i> c. v.) it was provided that &ldquo;in the most
+august assembly the bishop and alderman should be present, and
+the one should interpret to the people the law of God, the other
+the laws of men.&rdquo; Edgar, in a speech to St Dunstan and the
+bishops in synod (in 969), said, &ldquo;I hold in my hands the sword of
+Constantine, you that of Peter. Let us join right hands and
+unite sword to sword&rdquo; (Hardouin, <i>Conc.</i> tom. vi. p. 1, col. 675).
+The juxtaposition of the judicatures may, however, have led to
+some confusion between them.</p>
+
+<p>As to appeals the mixed council of Cliff at Hoo (747)
+said they should go to the synod of the province. The only
+appeal to Rome in Saxon times was that of St Wilfrid,
+bishop of York, who appealed from the division of his see and
+his deposition for refusing to consent to it, and was heard
+in a Roman synod under the presidency of Pope Agatho. The
+synod found him unlawfully deposed and ordered his restoration.
+Upon his return to England, the Roman judgment was refused
+recognition and he was for a time imprisoned. Ten years later he
+was recalled to York, but refusing to consent to the division of his
+see was again deposed and again appealed to Rome. The appeal
+was heard at great length, in a synod of 703 under John VI.,
+deputies from the archbishop of Canterbury being present.
+St Wilfrid was justified and was sent back to his see, with papal
+letters to the kings of Northumbria and Mercia. The Roman
+decree was again disregarded. At the council of &ldquo;Nid&rdquo; he was
+reconciled to the other bishops of the province, but not restored.
+In the end he was brought back to York, but not to the undivided
+see. The details of the case will be found in Wilkins, <i>Concilia</i>,
+in Mansi, <i>Concilia</i>, under the various councils named, and in
+Haddan &amp; Stubbs, <i>Councils and Eccl. Documents</i>, vol. iii.</p>
+
+<p>The penalties which the spiritual court could inflict, in the
+period between the edict of Milan and c. 854, were properly
+excommunication whether generally or as exclusion
+from the sacraments for a term of months or years or
+<span class="sidenote">Penalties inflicted by ecclesiastical courts.</span>
+till the day of death and (in the case of clerics) suspension
+or deposition. Gradually, however, doubtless by
+way of commutation of excommunication and of
+penance, temporal penalties were added, as scourging, banishment,
+seclusion in a monastery, fines. It is difficult to say how
+far some of these temporal penalties were penitential only or how
+far they could be inflicted <i>in invitos</i>. But the secular arm, from
+the time of Nicaea I., was in the habit of aiding spiritual decrees,
+as by banishing deposed bishops, and gradually by other ways,
+even with laymen. Scourging (although it had been a well-known
+punishment of the synagogue) was at first forbidden. Can. 28
+(26) of the Apostolic Canons imposes deposition on any bishop,
+priest or deacon striking the delinquent faithful. In Africa,
+however, a contrary practice early sprang up (see St Augustine,
+<i>Epist.</i> clix. <i>ad Marcellum al.</i> cxxxiii.). The small council of
+Vannes in Brittany in 465 made it an alternative punishment for
+clerks convicted of drunkenness (Can. 13). Canon 13 of the first
+council of Orleans, which has been cited in this matter, seems to
+have no application. St Gregory the Great seems to assume that
+scourging and seclusion in a monastery are in the discretion of
+episcopal tribunals (see <i>Epistles</i>, lib. ii. ep. 11, 40, 42, 44, 45; lib.
+vii. ep. 11, 67; lib. xii. ep. 31, c. 4). The 16th council of Toledo
+<span class="pagenum"><a name="page857" id="page857"></a>857</span>
+(in 693) has been cited as if it visited certain very great sinners
+with scourging as an ecclesiastical punishment. In fact, it only
+approves the punishment as ordered by the Visigothic laws.
+An alleged decree of a council of Autun in 670 is part of a code
+of discipline for monasteries (see authorities cited by Hefele,
+<i>Councils</i>, sect. 290, towards the end). Banishment does not
+seem to have been inflicted by the spiritual court <i>in invitum</i>.
+Seclusion in a monastery seems first to have been used by the
+civil power in aid of the spiritual. The fifth canon of the council
+of Macon, in 584, forbids clergy to dress like laymen and imposes
+a penalty of thirty days&rsquo; imprisonment on bread and water; but
+this may be merely penitential. There is little evidence of the
+imposition of fines as ecclesiastical penalties; but there are
+references to the practice in the epistles of St Gregory the Great,
+notably in his instructions to St Augustine. Gregory III. copies
+from St Gregory I. Probably these also were by way of penance.
+Isolated examples in the early middle ages of metropolitans dealing
+with their suffragan bishops by imprisonment in chains were
+extra-canonical abuses, connected with the perversion of Church
+law which treated the metropolitan (who originally was merely
+convener of the provincial synod and its representative during the
+intervals of sessions) as the feudal &ldquo;lord&rdquo; of his comprovincials.</p>
+
+<p>With the later 9th century we enter upon a new epoch, and by
+the time of Gregory VII., in the 11th century, the tribunals have
+fallen into the hands of a regular class of canonists who are in fact
+professional church-lawyers in orders. The changes due to the
+adoption of the False Decretals by Nicholas I. and the application
+of their principles by Hildebrand (afterwards Gregory VII.)
+are discussed in the article <span class="sc"><a href="#artlinks">Canon Law</a></span>. The later medieval
+system, thus inaugurated, may be considered (1) in its hierarchy,
+(2) in the subject matter of its jurisdiction, (3) in its penalties.</p>
+
+<p>1. (<i>a</i>) It is a system of courts. Much that had been done by
+bishops, <i>sine strepitu forensi et figura judicii</i>, is now done in the
+course of regular judicial procedure. Again, the court
+takes the place of the synod. The diocesan synod
+<span class="sidenote">Later medieval system.</span>
+ceases to have judicial work. The court of the metropolitan
+takes the place of the provincial synod, except
+possibly for the trial of bishops, and even this becomes doubtful.</p>
+
+<p>(<i>b</i>) At first the bishop was the only judge in the diocesan court
+and he always remains a judge. But just as the king appoints
+judges to hear <i>placita coram rege ipso</i>, and the feudal lord appoints
+his seneschal or steward, so the bishop appoints his official.</p>
+
+<p>(<i>c</i>) The archdeacon acquires a concurrent ordinary jurisdiction
+with the bishop (see <span class="sc"><a href="#artlinks">Archdeacon</a></span>). For some time it was considered
+that he was a mere office-holder dependent on the will of
+the bishop with a jurisdiction merely &ldquo;vicarial&rdquo;; but by the
+13th century it was settled that he held a &ldquo;benefice&rdquo; and that
+his jurisdiction over causes was ordinary and independent of the
+bishop (Van Espen, pars i. tit. xii. c. 1; Fournier, <i>Les Officialités
+au moyen âge</i>, p. 134). It was partly in order to counterpoise the
+power of archdeacons that bishops created officials (Fournier,
+p. 8). Archdeacons in course of time created officials who presided
+in court in their stead. The extent of jurisdiction of
+archdeacons depended much upon local customs. In England the
+custom was generally in their favour. Ordinarily, the appeal
+from an archdeacon or his official lay to the court of the bishop;
+but by custom the appeal might be to the court of the metropolitan:
+The Constitutions of Clarendon, in 1164, made the appeal
+from the court of the archdeacon lie to the court of the bishop.</p>
+
+<p>(<i>d</i>) The official of the bishop might be his official principal,
+who was his <i>alter ego</i>, or a special officer for a particular locality
+(<i>officialis foraneus</i>). The latter was treated as a mere delegate,
+from whom an appeal could be made to the bishop. The former
+had one consistory with the bishop, so that appeals from him
+had to be made to the court of the metropolitan. How far the
+official principal had jurisdiction in criminal matters by virtue
+of his office, how far it was usual to add this jurisdiction by
+special commission, and what were the respective limits of his
+office and that of the vicar-general, are questions of some nicety.
+The emphasis in Italy was on the vicar-general (<i>Sext. de officio
+Vicarii</i>). In the Low Countries, France and England the
+jurisdiction of the official principal was wider (Van Espen,
+pars i. tit. xii. cc. 4, 5; Fournier, p. 21). But he could not try
+criminal matters unless specially committed to him (Lyndwood,
+<i>Provinciale</i>, lib. ii. tit. 1). Later in England it became usual
+to appoint one man to the two offices and to call him chancellor,
+a word perhaps borrowed from cathedral chapters, and not in use
+for a diocesan officer till the time of Henry VIII. or later (see
+<span class="sc"><a href="#artlinks">Chancellor</a></span>). In Ireland the title, till the church was disestablished,
+was vicar-general.</p>
+
+<p>The importance of distinguishing the normal functions of an
+official principal and a vicar-general lies in this: that it was
+gradually established that as a king should not hear causes but
+commit them to his judges, so a bishop should not hear causes
+but appoint an official to hear them (see Ridley, <i>View of the
+Civil and Eccl. Law</i>; Ayliffe, <i>Parergon juris ecclesiastici</i>,
+p. 161; Godolphin, <i>Abridgement of the Laws Ecclesiastical</i>, p. 8).
+The &ldquo;parlements&rdquo; of France were constantly insisting on the
+independence and irremovability of the official (Fournier, p. 219).
+But jurisdiction which was not necessarily incident to the office
+of the official principal, that is to say voluntary jurisdiction,
+such as the granting of licences and institution to benefices,
+and criminal jurisdiction over clerks (and probably over laymen),
+the bishop could reserve to himself. Reservations of this nature
+are made in many English patents of chancellors and were held
+good in <i>R.</i> v. <i>Tristram</i>, 1902, 1 K.B. 816.</p>
+
+<p>(<i>e</i>) The ecclesiastical and temporal courts are kept distinct.
+The charter of William the Conqueror abrogated the laws of
+Edgar. No bishop or archdeacon &ldquo;shall any longer hold pleas
+in the Hundred concerning episcopal law nor draw a cause
+which concerns the rule of such to the judgment of men of the
+world&rdquo; (Stubbs, <i>Select Charters</i>, part iii.). In France, where
+the bishop was a temporal baron, his feudal and his spiritual
+courts were kept by distinct officers (Fournier, p. 2).</p>
+
+<p>(<i>f</i>) From the bishop, or his official, appeal lay to the metropolitan,
+who again could hear causes by his official. The Constitutions
+of Clarendon recognize this appeal (<i>c.</i> viii.).</p>
+
+<p>(<i>g</i>) An appeal lay from the court of the metropolitan to that
+of the primate. There were many disputes as to the existence
+of these primates (see Maitland, <i>Canon Law in the Church of
+England</i>, p. 121). In England the dispute between Canterbury
+and York was settled by making them both primates, giving
+Canterbury the further honour of being primate of all England.
+In France the primatial sees and the course of appeals to them
+were well established (Fournier, p. 219).</p>
+
+<p>(<i>h</i>) Several attempts were made by metropolitans and their
+officials to take causes arising in the dioceses of their comprovincials
+in the first instance and not by way of appeal. The
+officials of primates in their turn made similar attempts. After
+long struggles this was hindered, in France by the bull <i>Romana</i>
+(Fournier, p. 218), in England by the Bill of Citations, 23 Henry
+VIII. c. 9, and Canon 94 of the Canons of 1603. The preamble
+of the &ldquo;Bill of Citations&rdquo; is eloquent as to the mischief which
+it is framed to prevent. There are, however, a few cases in which
+the metropolitan is still allowed to cite in the first instance.
+One of them was in cases of &ldquo;perplexity.&rdquo; &ldquo;Perplexity&rdquo; arose
+where the suffragans &ldquo;could not owing to the geographical
+limitations of their competence do full justice&rdquo; (Maitland,
+pp. 118-119). Such was the case of probate where notable goods
+of the deceased lay in more than one diocese. Hence the origin
+of the &ldquo;prerogative court&rdquo; of Canterbury (cf. Van Espen, pars i.
+tit. xix.; and for Spain, Covarruvias, <i>Pract. Quaest.</i> c. 9).</p>
+
+<p>(<i>i</i>) Gradually there grew up a mass of peculiar and exempt
+jurisdictions (Ayliffe, pp. 417, 418; Phillimore, Eccl. Law, pp.
+214, 927; de Maillane, <i>Dict. du droit canonique</i>, s.v. &ldquo;Exemptions&rdquo;).
+Exempt jurisdictions began with the monasteries and
+were matter of vehement discussion in the later middle ages.
+There were no true exemptions before the 11th century (Van
+Espen, pars iii. tit. xii.). Peculiar or special jurisdiction, equal
+to that of the bishop, was given to deans and chapters over the
+cathedral precincts and in places where they had corporate
+property (see <i>Parham</i> v. <i>Templer</i>, 3 Phil. Ecc. R. 22). Sometimes
+it was given to deans alone or to prebendaries in the parishes
+whence they derived their prebends. Where the archdeacon
+<span class="pagenum"><a name="page858" id="page858"></a>858</span>
+had a jurisdiction co-ordinate with the bishop, it was called
+a peculiar. The metropolitans had peculiars within the dioceses
+of their comprovincials wherever they had residences or manors,
+and some whose origin is uncertain, <i>e.g.</i> that of the fifteen parishes
+in the deanery of the Arches. The official administering justice
+for the metropolitan was usually called a dean. From a peculiar
+jurisdiction ranking as episcopal the appeal lay to the court
+of the metropolitan. As to metropolitan peculiars, the metropolitan
+might give an appeal from the dean to his regular official
+principal. Thus, in Canterbury there was an appeal from the
+dean of Arches to the official principal of the Arches court.
+When peculiars were abolished (<i>vide infra</i>) the dean of Arches
+disappeared, and his title, in the 19th century, was erroneously
+given to the official principal. On peculiars in Spain cf. Covarruvias,
+<i>Works</i>, tit. i. p. 410. The French parlements, after the
+middle ages, discouraged them. In exempt convents the head
+of the monastery or priory exercised jurisdiction subject to
+an appeal to the pope.</p>
+
+<p>(<i>j</i>) It is said that originally a metropolitan had only one
+official principal, who, like the metropolitan himself, acted both
+for the diocese and province. Fournier (p. 219) says that in
+France it was not till the 17th century that there grew up a custom
+of having different officials for the metropolitan, one for him as
+bishop, a second as metropolitan, and even a third as primate,
+with an appeal from one to the other, and that it was an abuse
+due to the parlements which strove to make the official independent
+of the bishop. In England there has been, for a long time,
+a separate diocesan court of Canterbury held before the &ldquo;commissary.&rdquo;
+The word is significant as showing that there was
+something special and restricted about the position. In York
+there are two courts, one called the consistory for the diocese,
+the other called the chancery for the province. But the same
+person was often official of both courts.</p>
+
+<p>(<i>k</i>) In England the Constitutions of Clarendon added a provision
+for appeal to the king, &ldquo;and if the archbishop shall have
+failed in doing justice recourse is to be had in the last resort
+(<i>postremo</i>) to our lord the king, that by his writ the controversy
+may be ended in the court of the archbishop; because there
+must be no further process without the assent of our lord the
+king.&rdquo; The last words were an attempt to limit further appeal
+to Rome. It will be observed that the king does not hear the
+cause or adjudicate upon it. He merely corrects slackness or
+lack of doing justice (<i>Si archiepiscopus defecerit in justitia
+exhibenda</i>) and by his writ (<i>precepto</i>) directs the controversy
+to be determined in the metropolitan&rsquo;s court. As bishop
+Stubbs says (<i>Report of Eccl. Comm.</i> vol. i. <i>Hist. App.</i> i.): &ldquo;The
+appeal to the king is merely a provision for a rehearing before
+the archbishop, such failure to do justice being not so much
+applicable to an unfair decision as to the delays or refusal to
+proceed common at that time&rdquo; (cf. Joyce, <i>The Sword and the
+Keys</i>, 2nd ed. pp. 19-20). The <i>recursus ad principem</i>, in some
+form or other of appeal or application to the sovereign or his lay
+judges, was at the end of the middle ages well known over
+western Europe. This recourse in England sometimes took the
+form of the appeal to the king given by the Constitutions of
+Clarendon, just mentioned, and later by the acts of Henry VIII.;
+sometimes that of suing for writs of <i>prohibition</i> or <i>mandamus</i>,
+which were granted by the king&rsquo;s judges, either to restrain excess
+of jurisdiction, or to compel the spiritual judge to exercise
+jurisdiction in cases where it seemed to the temporal court that
+he was failing in his duty. The <i>appellatio tanquam ab abusu</i>
+(<i>appel comme d&rsquo;abus</i>) in France was an application of a like
+nature. Such an appeal lay even in cases where there was a
+refusal to exercise voluntary jurisdiction (de Maillane, <i>Dictionnaire
+du droit canonique</i>, tit. &ldquo;Abus,&rdquo; cf. tit. &ldquo;Appel&rdquo;). This writer
+traces their origin to the 14th century; but the procedure does
+not seem to have become regularized or common till the reigns
+of Louis XII. or Francis I. (cf. <i>Dict. eccl.</i>, Paris, 1765, titt. &ldquo;Abus&rdquo;
+and &ldquo;Appel comme d&rsquo;abus&rdquo;). On the <i>recursus ad principem</i> and
+the practice of &ldquo;cassation&rdquo; in Belgium, Germany and Spain,
+cf. Van Espen&rsquo;s treatise under this title (<i>Works</i>, vol. iv.) and
+<i>Jus eccles. univ.</i> pars iii. tit. x. c. 4. Louis XIV. forbad
+the parlements to give judgment themselves in causes upon an
+<i>appel comme d&rsquo;abus</i>. They had to declare the proceedings null
+and abusive and command the court Christian to render right
+judgment (Edict of 1695, arts. 34, 36, cited in Gaudry, <i>Traité
+de la législation des cultes</i>, Paris, 1854, tom. i. pp. 368, 369).</p>
+
+<p>In Catalonia &ldquo;Pragmatics,&rdquo; letters from the prince, issued
+to restrain jurisdiction assumed by ecclesiastical judges contrary
+to the customs of the principality. Thus in 1368 Peter III.
+evoked to the royal court a prosecution for abduction pending
+before the archbishop of Tarragona, declaring that the archbishop
+and the official were incompetent to judge noblemen.
+See this and other instances collected in <i>Usages y demas derechos
+de Cataluña</i>, by Vives y Cebriá (Barcelona, 1835), tom. iv. p. 137
+et seq.</p>
+
+<p>(<i>l</i>) Lastly there was the appeal to the patriarchs, <i>i.e.</i> in the
+West to Rome. The distinguishing feature of this appeal was
+that the rule of the other appeals did not apply to it. In the
+regular course of those appeals an appellant could not leap the
+intermediate stages; but he could at any stage go to this final
+appeal, <i>omisso medio</i>, as it was technically called (see <i>de appell.
+c. Dilect.</i> iii. for general rule, and c. 3 <i>de appell.</i> in 6 for different
+rule in case of the pope, and authorities cited in Van Espen,
+pars iii, tit. x. c. 2, 5). Van Espen says: &ldquo;The whole right of
+appeal to the Roman pontiff <i>omisso medio</i> had undoubtedly
+its origin in this principle, that the Roman pontiff is ordinary of
+ordinaries, or, in other words, has immediate episcopal authority
+in all particular churches, and this principle had its own beginning
+from the False Decretals.&rdquo;</p>
+
+<p>Appeals to Rome lay from interlocutory as well as final
+judgments. Causes could even be evoked to Rome before any
+judgment and there heard in first instance (Van Espen, pars iii.
+tit. x. c. 1, 8).</p>
+
+<p>There was an alleged original jurisdiction of the pope, which
+he exercised sometimes by permanent legates, whom Gregory
+VII. and his successors established in the chief countries of
+Europe, and to whom were committed the legislative executive
+and judicial powers of the spiritual &ldquo;prince&rdquo; in the districts
+assigned to them. These Clement IV. likened to &ldquo;pro-consuls&rdquo;
+and declared to have &ldquo;ordinary&rdquo; jurisdiction; because they
+had jurisdiction over every kind of cause, without any special
+delegation, in a certain defined area or province (c. ii. <i>de
+Officio Legati</i> in 6). They were expressed to have not merely
+appellate but original jurisdiction over causes (iii. c. i. <i>de Officio
+Legati</i>). The occupants of certain sees by a kind of prescription
+became legates without special appointment, <i>legati nati</i>, as in
+the case of Canterbury. In the 13th century Archbishop Peckham,
+says Maitland (p. 117), as archbishop &ldquo;asserted for himself
+and his official (1) a general right to entertain in the first instance
+complaints made against his suffragans&rsquo; subjects, and (2) a
+general right to hear appeals <i>omisso medio</i>.&rdquo; It was, for the
+time, determined that the archbishop might himself, in virtue
+of his legatine authority, entertain complaints from other
+dioceses in first instance, but that this legatine jurisdiction was
+not included in the ordinary jurisdiction of his official principal,
+even if the archbishop had so willed it in his commission. In
+fact, however, the official did before the end of the later medieval
+period get the same power as the archbishop (Maitland, pp. 118-120;
+cf. Lyndwood, lib. v. tit. 1), till it was taken from him
+by the Bill of Citations.</p>
+
+<p>After legates came special delegates appointed by the pope
+to hear a particular cause. It was the general practice to appoint
+two or three to sit together (Van Espen, pars iii. tit. v. c. 2, 37).
+These might sub-delegate the whole cause or any part of it as
+they pleased, <i>ibid.</i> 9-18. Dr Maitland (essay on &ldquo;The Universal
+Ordinary&rdquo;) thinks, but without very much foundation, that great
+numbers especially of the more important causes were tried
+before these delegates; although the records have largely perished,
+since they were the records of courts which were dissolved as soon
+as their single cause had been decided. These courts were convenient,
+since it was the custom to appoint delegates resident
+in the neighbourhood, and the power of sub-delegation, general
+or limited, simplified questions of distance. In Belgium causes
+<span class="pagenum"><a name="page859" id="page859"></a>859</span>
+appealed to Rome had to be committed to local delegates (Van
+Espen, pars iii. tit. v. c. 3, tit. x. c. 2).</p>
+
+<p>There could be an appeal from these delegates to the pope and
+from the pope himself to the pope &ldquo;better informed&rdquo; (Van
+Espen, pars iii. tit. x. c. 2, 12, 13). So personal had the
+system of jurisdiction become that even the trials of bishops
+ceased to be necessarily conciliar. Generally they were reserved
+to the pope (Van Espen, pars iii. tit. iii. c. 5, 17-19); but in
+England the archbishop, either in synod, or with some of his
+comprovincial bishops concurring, tried and deposed bishops
+(see case of Bishop Peacock and the other cases cited in <i>Read</i>
+v. <i>Bishop of Lincoln</i>, 14 P.D. 148, and Phillimore, <i>Eccl. Law</i>,
+pp. 66 et seq.).</p>
+
+<p>(<i>m</i>) The jurisdiction of a bishop <i>sede vacante</i> passed, by general
+law, to the dean and chapter; but in England the metropolitans
+became &ldquo;guardians&rdquo; of the spiritualities and exercised original
+jurisdiction through the vacant diocese (Phillimore, pp. 62-63),
+except in the case of Durham, and with a peculiar arrangement
+as to Lincoln.</p>
+
+<p>If the metropolitan see were vacant the jurisdiction was
+exercised by the dean and chapter through an official (Rothery,
+<i>Return of Cases before Delegates</i>, Nos. 4, 5). As to France see
+Fournier, p. 294.</p>
+
+<p>(<i>n</i>) Officials, even of bishops and metropolitans, need not be
+in holy orders, though Bishop Stubbs in his paper in the <i>Report
+of the Commission on Ecclesiastical Courts</i> seems to say so.
+They had to be clerics, that is, to have received the tonsure.
+Even papal delegates might be simple clerks (Van Espen, pars
+iii. tit. v. c. 2, 20).</p>
+
+<p>It came, however, to be the practice to impose some restrictions,
+as on clerks twice married. Thus Archbishop Chichele provided
+that no clerk married or bigamous (that is, having had two wives
+in succession) should exercise spiritual jurisdiction (see Lyndwood,
+lib. iii. tit. 3). Abroad unsuccessful attempts were made by
+local councils to enact that officials and vicars-general should
+be in holy orders (Hefele on Councils of Tortosa in 1429 and
+Sixth of Milan in 1582). These councils, as will be seen, are late.</p>
+
+<p>(<i>o</i>) With or without the concurrence and goodwill of the
+national Church, restrictions were imposed by the State on the
+papal jurisdiction, whether original or appellate. In England
+the Constitutions of Clarendon (by chap. viii.) prohibited appeals
+to the pope; but after the murder of St Thomas of Canterbury
+Henry II. had to promise not to enforce them. The statutes 38
+Edw. III. st. 2, 13 Rich. II. st. 2, c. 2, and 16 Rich. II. c. 5 forbid
+such appeals; but it is suggested that notwithstanding the
+generality of their language they refer only to cases of temporal
+cognizance. Cases upon the execution of these statutes are
+collected in Stillingfleet, <i>On Ecclesiastical Jurisdiction</i>, p. 189;
+Gibson, <i>Codex</i>, 83. Obstacles were placed in the way of appeals
+to the pope <i>omisso medio</i>. Thus when a writ of <i>significavit</i>
+issued on the mandate of a bishop, an appeal to Rome availed
+not to stay execution; but if there were an appeal to the archbishop
+it was otherwise. It therefore became the custom to
+lodge a double appeal: one to the archbishop &ldquo;for defence,&rdquo;
+and the other to the pope as the real appeal (&ldquo;Hostiensis,&rdquo;
+<i>Super Decret.</i> ii. fol. 169; cf. Owen, <i>Institutes of Canon Law</i>,
+1884, pt. i. c. 19, 5).</p>
+
+<p>There seems to have been no machinery for assisting the
+original or appellate jurisdiction of the pope by secular process,&mdash;by
+<i>significavit</i> or otherwise.</p>
+
+<p>The matrimonial cause between Henry VIII. and Catharine of
+Aragon was the most famous English cause tried by delegates
+under the &ldquo;original&rdquo; jurisdiction of the pope, and was ultimately
+&ldquo;evoked&rdquo; to Rome. The foreseen adverse termination of this
+long-drawn cause led to Henry&rsquo;s legislation.</p>
+
+<p>When the temporal courts interfered to prevent excess of
+jurisdiction, they did so by prohibiting the ecclesiastical court
+from trying and the suitor from suing in that court. The pope
+could not be effectively prohibited, and no instance is recorded
+of a prohibition to papal delegates. But suitors have been
+prohibited from appealing to the pope (see per Willes, J., in <i>Mayor
+of London</i> v. <i>Cox</i>, L.R. 2 H.L. 280). Whatever may have been
+the law, it is certain that, notwithstanding the statutes of Edw.
+III. and Rich. II., appeals to Rome and original trials by papal
+delegates did go on, perhaps with the king&rsquo;s licence; for the
+statute 24 Hen. VIII. c. 12 recites that the hearing of appeals was
+an usurpation by the pope and a grievous abuse, and proceeds
+to take away the appeal in matrimonial, testamentary and tithe
+causes, and to hinder by forbidding citation and process from
+Rome, all original hearings also. The statute 25 Hen. VIII. c. 19
+follows this up by taking away appeals in all other subjects of
+ecclesiastical jurisdiction.</p>
+
+<p>In 1438 the council of Basel took away all papal original
+jurisdiction (save in certain reserved cases&mdash;of which <i>infra</i>),
+evocation of causes to Rome, appeals to Rome <i>omisso medio</i>, and
+appeals to Rome altogether in many causes. Such appeals when
+permissible, except the &ldquo;greater,&rdquo; were to be tried by delegates
+on the spot (31st Session; Mansi, <i>Concilia, in loco</i>). These
+proceedings at Basel were regarded at Rome as of no effect.
+Nevertheless this decree and others were adopted by a French
+national council at Bourges and promulgated by the king as a
+&ldquo;Pragmatic Sanction&rdquo; (Migne, <i>Dict. du droit canonique</i>,
+&ldquo;Pragmatique Sanction&rdquo;). The parlements registered the
+Sanction and the effect was permanent in France. Louis XI.
+and Charles VIII. sought to revoke it; but both parlements
+and states-general refused to recognize the revoking decrees.
+In 1499 Louis XII. ordered the Pragmatic to be inviolably
+observed. The parlements thereupon condemned several private
+persons for obtaining bulls from Rome. In 1516 a Concordat
+between Leo X. and Francis I. settled all these questions in the
+sense of the Pragmatic, substantially according to the Basel
+canon. All causes, except the &ldquo;greater,&rdquo; were to be terminated
+in the country where the proper cognizance would lie (Migne,
+<i>op. cit.</i> &ldquo;Concordat&rdquo;). By this Concordat, by an ordinance of
+Francis I. in 1539, by two or three other royal edicts, and (above
+all) by the practice of the parlements, explanatory of this legislation,
+and their <i>arrêts</i>, the conflict of secular and ecclesiastical
+jurisdictions was settled until the Revolution (Migne, <i>ubi sup.</i>).
+&ldquo;Greater causes&rdquo; came in France to be restricted to criminal
+prosecutions of bishops. Even in these the original jurisdiction
+of the pope was taken away. In first instance they were tried
+by the provincial synod. Thence there was appeal to the pope
+(de Maillane, <i>op. cit.</i> <i>s.v.</i> &ldquo;Causes majeures&rdquo;; <i>Dict. eccl.</i>, Paris,
+1765, <i>s.v.</i> &ldquo;Cause&rdquo;). The only original jurisdiction left to the
+pope was in the case of the matrimonial causes of princes. But
+they could only be heard on the spot by judges delegate.
+Examples are the causes of Louis XII. and Jeanne of France in
+1498, and of Henry IV. and Marguerite of Valois in 1599 (Migne,
+<i>op. cit.</i> <i>s.v.</i> &ldquo;Causes&rdquo;). The prohibition of papal interference
+was enforced if necessary by the <i>appel comme d&rsquo;abus</i> (<i>vide supra</i>).
+Out of respect for the pope this appeal was not brought against
+his decrees but against their execution (<i>Dict. eccl.</i>, Paris, 1765,
+<i>s.v.</i> &ldquo;Abus&rdquo;).</p>
+
+<p>Spain appears to have permitted and recognized appeals to
+the pope. A royal writ of the 16th century cited by Covarruvias
+(c. xxxv.) prohibits execution of the sentence of a Spanish court
+Christian pending an appeal to the pope.</p>
+
+<p>2. The subject matter over which the ecclesiastical courts had
+jurisdiction was no longer purely &ldquo;criminal&rdquo; with a civil quasi-jurisdiction
+by way of arbitration. In the later middle
+ages these courts had jurisdiction over most questions,
+<span class="sidenote">Civil jurisdiction.</span>
+except indeed the then most important ones, those
+relating to real property. This civil jurisdiction was
+sometimes concurrent with that of the secular courts, sometimes
+exclusive. For England it may be thus classified:&mdash;</p>
+
+<p>(<i>a</i>) <i>Matrimonial.</i>&mdash;This arose naturally from the sacred
+character of Christian marriage. This jurisdiction was exclusive.
+From it followed the right of the courts Christian to pronounce
+upon questions of legitimacy. Upon this right an inroad was
+early made, in consequence of the question of legitimation by
+subsequent marriage. In the 12th century the Church&rsquo;s rule,
+that subsequent marriage did legitimize previous issue, was
+settled (c. 6, x. 4, 17). The king&rsquo;s judges then began to ask the
+ordinary the specific question whether A. B. was born before
+<span class="pagenum"><a name="page860" id="page860"></a>860</span>
+or after his parents&rsquo; marriage. After the inconclusive proceedings
+at the realm-council of Merton (1236), when spiritual and
+temporal lords took opposite views, the king&rsquo;s judges went a step
+further and thenceforward submitted this particular question
+to a jury. All other questions of legitimacy arising in the
+king&rsquo;s courts were still sent for trial to the bishop and concluded
+by his certificate (see Pollock and Maitland, <i>Hist. Eng. Law
+before Edward I.</i> vol. i. 105-106; Maitland, <i>ubi supra</i>, pp.
+53-56).</p>
+
+<p>(<i>b</i>) <i>Testamentary and in regard to succession from intestates.</i>&mdash;Real
+property was not the subject of will or testament in the
+medieval period. But as to personal property, the jurisdiction
+of the courts Christian became exclusive in England. The
+Church, East and West, had long asserted a right to supervise
+those legacies which were devoted to pious uses, a right recognized
+by Justinian (<i>Cod.</i> i. 3. 46). The bishop or, failing him, the
+metropolitan, was to see such legacies properly paid and applied
+and might appoint persons to administer the funds (Pollock and
+Maitland, <i>op. cit.</i> ii. 330). This right and duty became a jurisdiction
+in all testamentary causes. Intestacy was regarded with
+the greatest horror, because of the danger to the intestate&rsquo;s soul
+from a death without a fitting part given to pious uses (Maine,
+<i>Ancient Law</i>, ed. 1906, note by Pollock, p. 230; cf. Pollock and
+Maitland, <i>op. cit.</i> ii. 354). Hence came the jurisdiction of the
+ordinary in intestacy, for the peace of the soul of the departed.
+This head of ecclesiastical jurisdiction was in England not
+transferred to the secular court till 1857.</p>
+
+<p>(<i>c</i>) <i>Church Lands.</i>&mdash;If undoubtedly held in <i>frankalmoign</i> or
+&ldquo;free alms,&rdquo; by a &ldquo;spiritual&rdquo; tenure only, the claim of jurisdiction
+for the ecclesiastical <i>forum</i> seems to have been at first
+conceded. But the Constitutions of Clarendon (c. 9) reserved
+the preliminary question, of &ldquo;frankalmoign&rdquo; or not, for a jury
+in the king&rsquo;s court. Then, if the tenure were found free alms,
+the plea was to be heard in the court Christian. From the 13th
+century, however, inclusive, the king&rsquo;s courts insisted on their
+exclusive jurisdiction in regard to all realty, temporal or
+&ldquo;spiritual&rdquo; (Pollock and Maitland, <i>op. cit.</i> i. 106).</p>
+
+<p>(<i>d</i>) <i>Title to present to and possession of benefices.</i>&mdash;As to the
+title to present to benefices, the courts Christian at one time had
+concurrent jurisdiction with the temporal courts. &ldquo;Advowsons&rdquo;
+were, however, looked upon as a species of &ldquo;real&rdquo; property in
+England, and therefore the king&rsquo;s court early claimed exclusive
+jurisdiction in disputes where the title to present was involved.
+The Constitutions of Clarendon provided that these causes should
+be heard only in the king&rsquo;s court (c. 1). This rule was applied
+even where both litigants were &ldquo;spiritual.&rdquo; In the 13th century
+abbots sue each other in the royal court for advowsons (Selden
+Soc. <i>Select Civil Pleas</i>, i. pl. 245). In 1231, in such a suit, the
+bishop of London accepts wager of battle (Pollock and Maitland,
+<i>op. cit.</i> i. 105). In cases, however, where the title to present was
+not in question, but the fitness of the clerk presented, or, in
+cases of election to benefices, the validity of the election, there
+was jurisdiction in the courts Christian.</p>
+
+<p>(<i>e</i>) <i>The recovery of tithes and church dues,</i> including in
+England church rates levied to repair or improve churches and
+churchyards.</p>
+
+<p>(<i>f</i>) Questions concerning <i>fabrics, ornaments, ritual and ceremonial</i>
+of churches.</p>
+
+<p>(<i>g</i>) <i>Administration of pious gifts and revenues given to prelates
+or convents.</i>&mdash;Their right application could be effectively enforced
+only in the courts Christian; until the rise in England of the
+equitable jurisdiction of the court of chancery and the development
+of the doctrine of &ldquo;uses&rdquo; at the end of the middle
+ages.</p>
+
+<p>(<i>h</i>) <i>Enforcement of contractual promises made by oath or pledge
+of faith.</i>&mdash;The breaking of such a promissory oath was called
+&ldquo;perjury&rdquo; (as in classical Latin and in Shakespeare), contrary
+to modern usage which confines the word to false evidence
+before a court of justice. In regard to the execution of these
+promises, the jurisdiction of the ecclesiastical courts was possibly
+traversed by c. 15 of the Constitutions of Clarendon; but
+allowed by the statute 13 Edw. I. st. 4. As just intimated,
+besides the enforcement of the promise, the &ldquo;perjury&rdquo; was
+treated as an ecclesiastical crime.</p>
+
+<p>The <i>criminal jurisdiction of courts Christian over laymen</i>
+included, besides these &ldquo;perjuries,&rdquo; (<i>a</i>) all <i>sexual offences</i> not
+punishable on indictment; (<i>b</i>) <i>Defamation of character</i> (the
+king&rsquo;s courts came in time to limit this to such defamation as
+could not be made the subject of a temporal action); (<i>c</i>) <i>Offences
+by laymen against clerks</i> (<i>i.e.</i> against all &ldquo;tonsured&rdquo; persons,
+supra); (<i>d</i>) <i>Offences in regard to holy places</i>&mdash;&ldquo;brawling&rdquo; and
+such like; (<i>e</i>) <i>Heresy, schism, apostasy, witchcraft</i>.</p>
+
+<p>In regard to &ldquo;clerks,&rdquo; there was (1) all the criminal jurisdiction
+which existed over laymen, and (2) criminal jurisdiction
+in regard to professional misconduct. Concerning &ldquo;felonious&rdquo;
+clerks the great questions discussed were whether the courts
+Christian had exclusive jurisdiction or the king&rsquo;s court, or
+whether there was a concurrent jurisdiction. The subject was
+dealt with in the Constitutions of Clarendon, formally revoked
+after the murder of St Thomas of Canterbury. In the 13th
+century it was recognized that a &ldquo;clerk&rdquo; for felony was subject
+only to ecclesiastical trial and punishment; punishment which
+might involve lifelong imprisonment. For &ldquo;misdemeanours,&rdquo;
+as yet unimportant, he had no exemption from secular jurisdiction
+(Pollock and Maitland, <i>op. cit.</i> ch. iv.). At some indeterminate
+later period, the &ldquo;clerk&rdquo; was tried for felony by a jury
+in the king&rsquo;s court and then &ldquo;pleaded his clergy,&rdquo; after conviction
+there, and was remitted to the ordinary for ecclesiastical punishment.
+&ldquo;Clerks&rdquo; for the purpose of &ldquo;benefit of clergy&rdquo; included
+not only persons in minor orders, but all &ldquo;religious&rdquo; persons,
+<i>i.e.</i> monks, friars, nuns, &amp;c. Later the custom arose of taking
+&ldquo;clerk&rdquo; to include any &ldquo;literate,&rdquo; even if not in orders or
+&ldquo;religious&rdquo; (cf. Stephen, <i>Hist. Crim. Law</i>, i. 461). The statute
+4 Hen. VII. c. 13 took away benefit of clergy, if claimed a
+second time, from persons not &ldquo;within orders,&rdquo; in certain bad
+cases. 4 Hen. VIII. c. 2 (a temporary act) took away &ldquo;clergy,&rdquo;
+in certain heinous crimes, from all persons not in &ldquo;holy&rdquo;
+orders. This statute was partly renewed by 22 Hen. VIII.
+c. 13. Other changes were introduced by 23 Hen. VIII. c. 1
+and later acts. In time, &ldquo;benefit of clergy&rdquo; became entirely
+diverted from its original objects.</p>
+
+<p>In <i>France</i>, till 1329, there seems to have been no clear line of
+demarcation between secular and ecclesiastical jurisdictions.
+Beaumanoir (<i>Coutume de Baulvoisis</i>, ch. xi., cited Gaudry,
+<i>op. cit.</i> i. 22) had laid down the principle that spiritual justice
+should meddle only with spiritual things. In the year named
+the secular courts complained to the king, Philip of Valois, of
+the encroachments of the courts Christian. The &ldquo;cause&rdquo; was
+solemnly argued before that monarch, who decided to leave
+things as they were (Migne, <i>Dict. du droit canon.</i>, <i>s.v.</i> &ldquo;Officialités&rdquo;).
+In 1371 Charles V. forbade spiritual courts to take
+cognizance of &ldquo;real&rdquo; and &ldquo;possessory&rdquo; actions even in regard
+to clerks (Migne, <i>loc. cit.</i>; cf. Gaudry, <i>ubi sup.</i>). From this
+period the parlements began the procedure which, after the
+Pragmatic Sanction of Charles VII., in 1438 took regular shape
+as the <i>appel comme d&rsquo; abus</i> (<i>supra</i>; Migne, <i>loc. cit.</i>). Testamentary
+causes at first were subject to the concurrent jurisdiction of the
+spiritual and secular courts. After the 14th century, the latter
+had exclusive jurisdiction (Van Espen, <i>op. cit.</i> lib. iii. tit. ii.
+cc. 2, 15, 16). In regard to <i>marriage</i> the secular jurists distinguished
+between the civil contract and the sacrament, for
+purposes of separating the jurisdiction (<i>Dict. eccl.</i>, Paris, 1765,
+<i>s.v.</i> &ldquo;Mariage&rdquo;). The voluntary jurisdiction as regards dispensations
+was kept for the Church. The contentious jurisdiction
+of the courts Christian was confined to promises of marriage,
+nullity of marriage caused by &ldquo;diriment&rdquo; impediments only,
+validity or invalidity of the sacrament, divorce <i>a thoro</i> (<i>ibid.</i>).
+Questions in regard to the <i>property in a benefice</i> were for the
+courts Christian; in regard to its <i>possession</i>, for the king&rsquo;s
+courts. But if a &ldquo;possessory&rdquo; action had been brought in the
+latter, a subsequent suit in the courts spiritual for the property
+was deemed &ldquo;abusive&rdquo; and restrained (<i>ib., s.v.</i> &ldquo;Pétitoire&rdquo;)
+<i>Breach of faith or of promise confirmed by oath</i> was matter for
+the court Christian (Fournier, pp. 95, 99, 109, 125). This
+<span class="pagenum"><a name="page861" id="page861"></a>861</span>
+branch of jurisdiction was larger and more freely used than in
+England (cf. Pollock and Maitland, <i>op. cit.</i>, as to Normandy).
+The only other remaining civil jurisdiction of the ecclesiastical
+courts was in <i>personal actions where clerks were defendants</i> (Migne,
+<i>op. cit.</i>, <i>s.v.</i> &ldquo;Officialités,&rdquo; Fournier, pp. 65-125); or, after
+the 14th century, where both parties were clerks. In regard to
+crimes delicts (<i>délits</i>) were divided into classes for purposes of
+jurisdiction. Clerks were punishable only in the court Christian,
+except in cases of grave crimes such as murder, mutilation
+(Fournier, p. 72), and cases called &ldquo;royal cases&rdquo; (<i>vide infra</i>).
+Laymen were punishable in the court Christian for the <i>délits</i>
+following: injury to sacred or religious places, sacrilege, heresy
+(except where it was a &ldquo;royal case&rdquo;), sorcery, magic, blasphemy
+(also punishable in the secular court), adultery, simony, usury
+and infractions of the truce of God (Fournier, pp. 90-93). What
+were called &ldquo;privileged delicts&rdquo; were judged in the case of the
+clergy conjointly by the spiritual judge and the king&rsquo;s judge.
+Bishops had no exemption (<i>Dict. ecc.</i>, <i>s.v.</i> &ldquo;Délits,&rdquo; &ldquo;Cas
+privilégié,&rdquo; &ldquo;Causes majeures&rdquo;). &ldquo;Royal cases&rdquo; included
+such crimes as touched the prince, as all forms of treason; or
+the dignity of his officers; or the public safety. In this class
+were also included such heresies as troubled the state, as by
+forbidden assemblies, or by teaching prohibited doctrine.
+Among these heresies were reckoned idolatry, atheism, Protestantism,
+relapse (<i>ib. et</i> &ldquo;Cas royaux,&rdquo; &ldquo;Hérésie&rdquo;). These
+were of exclusive royal jurisdiction as against both spiritual
+courts and the courts of feudal lords. A similar claim was made
+by Pombal for Portugal (<i>vide infra</i>).</p>
+
+<p>The parlements, in order to have a ready means of enforcing
+all these restrictions by <i>appel comme d&rsquo;abus</i>, compelled the
+bishops to appoint officials, Frenchmen, graduates, and (as it
+seems) &ldquo;seculars&rdquo; (<i>Dict. eccl.</i>, Paris, 1765, <i>s.v.</i> &ldquo;Official&rdquo;).
+This last qualification was disputed (see Fevret, <i>Traité de l&rsquo;abus</i>).</p>
+
+<p>3. <i>Punishments.</i>&mdash;Ecclesiastical sanctions were divided into
+<i>punishments</i> (<i>poenae</i>), either purely temporal in character or else
+of a mixed spiritual and temporal character, and <i>censures</i> (<i>censurae</i>),
+purely spiritual and remedial (see Van Espen, pars iii.
+tit. xl. cc. 1, 3; Phillimore, <i>Ecclesiastical Law</i>, p. 1064). In the
+book last cited <i>censurae</i> and <i>poenae</i> are classed together as
+&ldquo;censures&rdquo; (which is the modern use).</p>
+
+<p><i>Poenae.</i>&mdash;(<i>a</i>) Fines sprang from the older custom of directing
+alms by way of penance in the internal forum (Van Espen,
+<i>ubi sup.</i> c. 1, 5-10). They were to be applied to pious uses.
+(<i>b</i>) <i>Reclusion in a monastery</i> continued from former period,
+and might be either temporary or perpetual (<i>loc. cit.</i> 17-19).
+(<i>c</i>) <i>Imprisonment</i>, in the bishop&rsquo;s prison, might be in chains, or
+on bread and water, and temporary or perpetual. In its severer
+forms it was only inflicted for more atrocious crimes which the
+secular law would have punished with death (<i>loc. cit.</i> 21-27).
+The act 23 Henry VIII. c. 11 made special provision for convicted
+clerks who broke out of the prisons of the ordinary. (<i>d</i>) <i>Fustigation</i>,
+as in former period, was hardly an ecclesiastical punishment.
+If given, it was to be of a paternal character (<i>loc. cit.</i> 39-45).
+Punishments of a mixed nature were: (<i>e</i>) <i>Suspension</i> either
+from office alone or from office and benefice; (<i>f</i>) <i>Deprivation</i> of
+benefice; (<i>g</i>) <i>Deposition</i> or <i>Degradation</i> (a more solemn and
+ceremonial form) from the ministry; (<i>h</i>) <i>Irregularity</i>&mdash;not always
+a punishment&mdash;a state of incapacity to be ordained, or, being
+ordained, to execute the ministry; this might result from some
+defect of mind and body, but was also incurred by some grave
+offences.</p>
+
+<p><i>Censures</i> were as follows: (<i>i</i>) <i>Suspension</i> from attending
+divine offices or <i>ab ingressu ecclesiae</i>, more appropriate for a
+layman. A clerk in like case might be suspended from office.
+(<i>j</i>) <i>Interdict</i> was another form of partial or total suspension from
+the benefit of the rites and sacraments of the Church. An interdict
+might be personal or local (see <span class="sc"><a href="#artlinks">Interdict</a></span>). (<i>k</i>) <i>Excommunication</i>
+was either greater or less. The greater separated
+entirely from the Church. It might be pronounced under
+anathema. The less deprived of participation in the sacraments,
+and made a clerk incapable of taking a benefice.</p>
+
+<p>On the European continent the courts Christian often carried
+out their decrees by their own apparitors who could levy pecuniary
+penalties on a defendant&rsquo;s goods (Van Espen, pars iii. tit. ix.
+c. 4). They could arrest and imprison. In England, except in
+the peculiar case of imprisonment pending trial for heresy, or in
+the case of a clerk convicted of crime, these things could not be.
+The sentence of the court Christian had in all other cases to be
+enforced by the secular arm. Early in Henry II.&rsquo;s time it had
+become the custom of England for the court Christian to &ldquo;signify&rdquo;
+its sentence of excommunication to the king and to demand from
+him a writ of <i>significavit</i> to the sheriff, to imprison the person
+excommunicated. The writ apparently issued for no court
+inferior to the bishop&rsquo;s, unless upon the bishop&rsquo;s request. In
+some sense the king&rsquo;s writ of <i>significavit</i> was discretionary; but
+its issue could be enforced by excommunication or interdict.</p>
+
+<p>In the cases of heresy, apostasy and sorcery, the spiritual
+courts sought the aid of the secular jurisdiction to superadd the
+punishment of death. Incorrigible offenders on these matters
+were &ldquo;left&rdquo; to the secular power, to be corrected with due
+&ldquo;animadversion.&rdquo; This provision of the fourth Lateran Council
+in 1215 was always interpreted to mean death (see Van Espen,
+<i>Observ. in Conc. Lat. IV. Canones</i>, and the decree in the <i>Sext. ut
+inquisitionis negotium</i>; and, as to English law and practice,
+Maitland, <i>op. cit.</i>, Essay vi., and pp. 161, 176; 2 Hen. IV. c. 15;
+Fitzherbert, <i>Natura brevium</i>, 269; 2 Hen. V. st. 1, c. 7). The
+&ldquo;capital&rdquo; punishment was generally (always in England) by
+burning. Burning was an English punishment for some secular
+offences.</p>
+
+<p>The Concordat with Francis I. by which the pope gave up the
+right of hearing appeals from France was not many years before
+the legislation of Henry VIII. in England. Both monarchs
+proceeded on the same lines; but Francis I. got the pope&rsquo;s consent:
+Henry VIII. acted <i>in invitum</i>, and in time went rather
+further.</p>
+
+<p>The Statute of Appeals (24 Hen. VIII. c. 12) takes away
+appeals to Rome in causes testamentary and matrimonial and in
+regard to right of tithes, oblations and obventions.
+A final appeal is given to the archbishop of the particular
+<span class="sidenote">Ecclesiastical jurisdiction in England.</span>
+province; but in causes touching the king
+a final appeal is given to the Upper House of Convocation
+of the province. The statute is aimed at appeals;
+but the words used in it concerning &ldquo;citations and all other
+processes&rdquo; are wide enough to take away also the &ldquo;original&rdquo;
+jurisdiction of the pope. No appeal was yet given to the crown.
+Canterbury, York, Armagh, Dublin, Cashel and Tuam are put
+in the place of Rome. The English and Irish provinces are
+treated as self-contained. All ends there.</p>
+
+<p>The &ldquo;Act of Submission of the Clergy&rdquo; (25 Hen. VIII. c. 19)
+took away <i>all</i> appeals to Rome and gave a further appeal, &ldquo;for
+lack of justice,&rdquo; from the several courts of the archbishops to the
+king in chancery. Thence a commission was to issue to persons
+named therein to determine the appeal definitely. This was
+copied from the then existent practice in admiralty appeals and
+was the origin of the so-called court of delegates. It is a moot
+question whether this statute took away the appeal to the Upper
+Houses of the various convocations in causes wherein the king
+was concerned (see <i>Gorham</i> v. <i>Bishop of Exeter</i>, 15 Q.B. 52; <i>Ex
+parte Bishop of Exeter</i>, 10 C.B. 102; <i>Re Gorham</i> v. <i>Bishop of
+Exeter</i>, 5 Exch. 630). 37 Hen. VIII. c. 17 provided that married
+laymen might be judges of the courts Christian if they were
+doctors of civil law, created in any university. This qualification
+even was considered unnecessary in Charles I.&rsquo;s time (<i>Cro.
+Car.</i> 258). Canon 127 of 1603 provided that the judges must be
+learned in the civil and ecclesiastical laws and at least masters
+of arts or bachelors of laws. Canon Law as a study had been
+practically prohibited at the universities since 1536 (Merriman,
+<i>Thomas Cromwell</i>, i. 142-143; <i>Cal. State Papers</i>, vol. ix. p. xxix.
+117; Owen, <i>Institutes of Canon Law</i>, viii.). The substitution
+of &ldquo;civilians,&rdquo; rather than common lawyers, for canonists
+(civilians, hitherto, not an important body in England) had
+important consequences (see Maitland, <i>op. cit.</i> 92 et seq.).</p>
+
+<p>Henry VIII. had exercised his jurisdiction as Supreme
+Head through a vicar-general. Edward VI. exercised original
+<span class="pagenum"><a name="page862" id="page862"></a>862</span>
+jurisdiction in spiritual causes by delegated commissions (see
+Archdeacon Hale, <i>Precedents in Criminal Cases</i>, p. xlviii.). Unless
+the king was to be regarded as an ecclesiastical person, they were
+not properly ecclesiastical courts; although spiritual persons
+might sit in them, for they sat only as royal commissioners. The
+same point has been taken by large bodies of clergy and laity in
+regard to the court of final appeal created by 25 Hen. VIII. c. 19
+and its present successor the judicial committee of Privy Council
+(<i>infra: Rep. Com. Ecc. Discipline</i>, pp. 9, 94 et seq.). At any rate
+the &ldquo;original&rdquo; jurisdiction claimed for the monarch personally
+and his delegates, under Henry VIII. and Edward VI., has not
+permanently remained. In theory, Hooker&rsquo;s contentions have
+been conceded that &ldquo;kings cannot in their own proper persons
+decide questions about matters of faith and Christian religion&rdquo;
+and that &ldquo;they have not ordinary spiritual power&rdquo; (<i>Ecc. Pol.</i>
+vii. 8, 1, 6; cf. <i>XXXIX. Articles</i>, Art. 37).</p>
+
+<p>Under Henry VIII. a system began of making certain crimes,
+which previously had been only of spiritual cognizance, felonies
+(25 Hen. VIII. c. 6), excluding thereby spiritual jurisdiction
+(Stephen, <i>Hist. Crim. Law</i>, ii. 429). Bigamy (in its modern
+sense) was thus made felony (1 Jac. I. c. 11). In this reign and
+the next, temporal courts were sometimes given jurisdiction
+over purely spiritual offences. A trace of this remains in 1 Edw.
+VI. c. 1 (still on the statute book; Stephen, <i>Hist. Crim. Law</i>,
+ii. 439). Other traces occur in the Acts of Uniformity, which
+make offences of depraving the Book of Common Prayer triable
+at Assizes (between 23 Eliz. c. 1 and 7 &amp; 8 Vict. c. 102&mdash;also at
+Sessions) as well as in the courts Christian.</p>
+
+<p>During Edward VI.&rsquo;s time the courts Christian seem practically
+to have ceased to exercise criminal jurisdiction (Hale, <i>Precedents
+in Criminal Cases</i>, p. xlix.). But they sat again for this purpose
+under Mary and Elizabeth and (save between 1640 and 1661)
+continued regular criminal sessions till towards the end of the
+17th century as continuously and constantly as the king&rsquo;s courts
+(<i>op. cit.</i>).</p>
+
+<p>The &ldquo;ordinary&rdquo; ecclesiastical tribunals of the later middle
+ages still subsist in England, at least as regards the laity. This
+is hardly the case elsewhere in the Western Church, though some
+exceptions are noted below. Nevertheless, their exercise of
+criminal jurisdiction over the laity is now in practice suspended;
+although in law it subsists (see Stephen, <i>Hist. Crim. Law</i>; <i>Ray</i> v.
+<i>Sherwood</i>, 1 Curt. R. 193; 1 Moore P.C.R. 363; the observations
+of Kelly, C.B., in <i>Mordaunt</i> v. <i>Moncrieffe</i>, L.R. 2 Sc. &amp; Div. 381,
+and of Lord Coleridge in <i>Martin</i> v. <i>Mackonochie</i>, L.R. 4 Q.B.D.
+770, and, on the other hand, of Lord Penzance in <i>Phillimore</i> v.
+<i>Machon</i>, L.R. 1 P.D. 480). Theoretically still, in cases of sexual
+immorality, penance may be imposed. Monitions to amend
+may be decreed and be enforced by <i>significavit</i> and writ <i>de contumace
+capiendo</i>, or by excommunication with imprisonment not
+to exceed six months (53 Geo. III. c. 127). The tribunals thus
+subsisting are the courts of the bishop and archbishop, the latter
+sometimes called the court of appeal of the province. Peculiar
+jurisdictions have been gradually taken away under the operation
+of the acts establishing the ecclesiastical commissioners. The
+appeal given to delegates appointed by the crown has been
+transferred, first by 2 &amp; 3 Will. IV. c. 92 to the privy council,
+and then by 3 &amp; 4 Will. IV. c. 41 to the judicial committee of
+the privy council. Bishops may now be summoned as assessors
+by 39 &amp; 40 Vict. c. 59.</p>
+
+<p>There was in the time of Elizabeth, James I. and Charles I.
+a &ldquo;Court of High Commission&rdquo; with jurisdiction over laity
+and clergy, based on 1 Eliz. c. i. s. 15, which was reckoned as an
+ecclesiastical judicature (5 R. 1, <i>Cawdrey&rsquo;s case</i>) concurrent with
+the ordinary court Christian. It was created by virtue of the
+royal supremacy, and was taken away by 16 Car. I. c. 11. As
+to its history see Stephen, <i>Hist. Crim. Law</i>, ii. 414-428.</p>
+
+<p>In regard to clerical offences, 3 &amp; 4 Vict. c. 86 (the &ldquo;Church
+Discipline Act&rdquo;) creates new tribunals; and first a commission
+of inquiry appointed by the bishop of five persons, of whom the
+vicar-general, or an archdeacon, or a rural dean of the diocese
+must be one. If they report a <i>prima facie</i> case, the bishop may
+(with the consent of parties) proceed to sentence. In the absence
+of such consent, the bishop may hear the cause with three
+assessors, of whom one shall be a barrister of seven years&rsquo;
+standing and another the dean of the cathedral, or one of the
+archdeacons, or the chancellor. This court is called the &ldquo;consistory&rdquo;
+court, but is not the old consistory. Both these
+tribunals are new. But the bishop may instead send the cause, in
+first instance, to the old provincial court, to which appeal lies,
+if it be not so sent.</p>
+
+<p>The Public Worship Regulation Act (37 &amp; 38 Vict. c. 85) gave
+criminal jurisdiction over beneficed clerks (concurrent with
+that of the tribunal under 3 &amp; 4 Vict. c. 86) to the judge under
+the act in matters of the fabric, ornaments, furniture and decorations
+of churches, and the conduct of divine service, rites and
+ceremonies. The &ldquo;judge&rdquo; under the act is to be a barrister of
+ten years&rsquo; standing, or an ex-judge of a superior secular court,
+appointed by the archbishops of Canterbury and York, with the
+approval of the crown, or, if they fail to appoint, by the crown.
+Proceedings under this act are to be deemed to be taken in the
+appropriate ancient ecclesiastical courts (<i>Green</i> v. <i>Lord Penzance</i>,
+6 A. C. 657). The judge under this act became (upon vacancies
+occurring) <i>ex officio</i> official principal of the arches court of
+Canterbury and of the chancery court of York. This provision
+caused grave doubts to be entertained as to the canonical
+position of this statutory official principal.</p>
+
+<p>Finally, the Clergy Discipline Act 1892 (55 &amp; 56 Vict. c. 32)
+creates yet a new court of first instance for the trial of clerical
+offences against morality in the shape of a consistory court,
+which is not the old court of that name, but is to comprehend
+the chancellor and five assessors (three clergymen and two
+laymen chosen from a prescribed list), with equal power with the
+chancellor on questions of fact. In many instances the conviction
+of a temporal court is made conclusive on the bishop without
+further trial. In regard to moral offences, jurisdiction under this
+act is exclusive. But it only applies to clerks holding preferment.
+Under all these three acts there is a final appeal to the
+judicial committee of the privy council.</p>
+
+<p>None of these acts applies to the trial of bishops, who are left
+to the old jurisdictions, or whatever may be held to be the old
+jurisdictions (with that of the Roman See eliminated). As to
+suffragan bishops in the province of Canterbury, see <i>Read</i> v.
+<i>Bishop of Lincoln</i>, 13 P.D. 221, 14 P.D. 88. (On general questions
+see Phillimore, <i>Ecc. Law</i>, 65, 73.) Despite the bishop of
+Lincoln&rsquo;s case, the law is in some uncertainty.</p>
+
+<p>Dilapidations are now not made matters of suit before the
+court, but of administrative action by the bishop.</p>
+
+<p>The subject matter of ecclesiastical jurisdiction has been
+gradually reduced in England, &amp;c., by various causes. (1) The
+taking away of all matrimonial, testamentary and <i>ab intestate</i>
+jurisdiction by 20 &amp; 21 Vict. c. 77 (testamentary, &amp;c., England),
+c. 79 (testamentary, &amp;c., Ireland), c. 85 (matrimonial, England);
+33 &amp; 34 Vict. c. 110 (matrimonial, Ireland). Matrimonial jurisdiction
+was taken from the bishop of Sodor and Man in 1884. (2)
+Since 6 &amp; 7 Will. IV. c. 71, tithe has become, except in a few
+rare cases, tithe rent charge, and its recovery has been entirely
+an operation of secular law. Most kinds of offerings are now
+recoverable in secular courts. (3) Administration of pious gifts
+has passed to the court of chancery. (4) The enforcement of
+contractual promises has long been abandoned by the courts
+Christian themselves. (5) Church rates can no longer be enforced
+by suit (31 &amp; 32 Vict. c. 109). (6) <i>Defamation</i> was taken away
+in England by 18 &amp; 19 Vict. c. 41, and in Ireland by 23 &amp; 24
+Vict. c. 32. (7) Laymen can no longer be tried in the spiritual
+courts for offences against clerks. (8) The jurisdiction for
+&ldquo;brawling&rdquo; in church, &amp;c., is taken away by 23 &amp; 24 Vict. c. 32
+in the case of the laity. In the case of persons in holy orders there
+is a concurrent jurisdiction of the two tribunals (<i>Valancy</i> v.
+<i>Fletcher</i>, 1897, 1 Q.B. 265). This was an offence very frequently
+prosecuted in the courts Christian (see A.J. Stephens, <i>Ecclesiastical
+Statutes</i>, i. 336).</p>
+
+<p>The existing ecclesiastical jurisdiction in England is therefore
+now confined to the following points. (1) Discipline of the
+clergy. (2) Discipline of the laity in respect of sexual offences
+<span class="pagenum"><a name="page863" id="page863"></a>863</span>
+as already stated. (3) Control of lay office-bearers, church-wardens,
+sidesmen, organists, parish clerks, sextons. (4) Protection
+of the fabrics of churches, of churchyards, ornaments,
+fittings, &amp;c., sanctioning by licence or faculty any additions or
+alterations, and preventing or punishing unauthorized dealings by
+proceedings on the criminal side of the courts. (5) Claims by
+individuals to particular seats in church or special places of
+sepulture. (6) Rare cases of personal or special tithes, offerings
+or pensions claimed by incumbents of benefices. In the Isle of
+Man and the Channel Islands courts Christian have now jurisdiction
+substantially as in England. In Jersey and in Guernsey
+there are courts of first instance with appeal to the bishop of
+Winchester. Ecclesiastical jurisdiction in Ireland was as in
+England till the Irish Church was disestablished in 1869 by
+32 &amp; 33 Vict. c. 42.</p>
+
+<p>The position of a disestablished or an unestablished Church
+is comparatively modern, and has given rise to new jural conceptions.
+These Churches are <i>collegia licita</i> and come
+within the liberty of association so freely conceded in
+<span class="sidenote">Ecclesiastical jurisdiction in non-established churches.</span>
+modern times. The relations of their bishops, priests
+or other ministers and lay office-bearers <i>inter se</i> and
+to their lay folk depend upon contract; and these
+contracts will be enforced by the ordinary courts of
+law. A consensual ecclesiastical jurisdiction is thus created,
+which has to this extent temporal sanction. <i>In foro conscientiae</i>
+spiritual censures canonically imposed are as binding
+and ecclesiastical jurisdiction is as powerful as ever.</p>
+
+<p>Into the British-settled colonies no bishops were sent till 1787;
+and consequently there were no regular courts Christian. The
+bishop of London was treated as the diocesan bishop of the
+colonists in North America; and in order to provide for testamentary
+and matrimonial jurisdiction it was usual in the letters
+patent appointing the governor of a colony to name him ordinary.
+In New York state there is still a court called the surrogates
+court, surrogate being the regular name for a deputy ecclesiastical
+judge. In Lower Canada, by treaty, the Roman Catholic
+Church remained established.</p>
+
+<p>Throughout the United States, whatever may have been the
+position in some of them before their independence, the Church
+has now no position recognized by the State, but is just a body
+of believers whose relations are governed by contract and with
+whom ecclesiastical jurisdiction is consensual.</p>
+
+<p>The position is the same now through all the British colonies
+(except, as already mentioned, Lower Canada or Quebec). From
+1787 onwards, colonial bishops and metropolitans were appointed
+by letters patent which purported to give them jurisdiction for
+disciplinary purposes. But a series of cases, of which the most
+remarkable was that <i>Re the Bishop of Natal</i> (3 Moore P.C.
+N.S. <span class="scs">A.D.</span> 1864), decided that in colonies possessing self-governing
+legislatures such letters patent were of no value;
+and soon after the crown ceased to issue them, even for crown
+colonies.</p>
+
+<p>In India the metropolitan of Calcutta and the bishops of
+Madras and Bombay have some very limited jurisdiction which
+is conferred by letters patent under the authority of the statutes
+53 Geo. III. c. 155 and 3 &amp; 4 Will. IV. c. 85. But the other
+Indian bishops have no position recognized by the State and no
+jurisdiction, except consensual.</p>
+
+<p>The Church had the same jurisdiction in Scotland, and
+exercised it through similar courts to those which she had in
+England and France, till about 1570. As late as 1566
+Archbishop Hamilton of Glasgow, upon his appointment,
+<span class="sidenote">Ecclesiastical jurisdiction in Scotland.</span>
+had restitution of his jurisdiction in the probate
+of testaments and other matters (Keith, <i>History of
+the Scottish Bishops</i>, Edinburgh, 1824, p. 38). There was an
+interval of uncertainty, with at any rate titular bishops,
+till 1592. Then parliament enacted a new system of Church
+courts which, though to some extent in its turn superseded by
+the revival of episcopacy under James VI., was revived or ratified
+by the act of 1690, c. 7, and stands to this day. It is a Presbyterian
+system, and the Scottish Episcopal Church is a disestablished
+and voluntary body since 1690.</p>
+
+<p>The Presbyterian courts thus created are arranged in ascending
+order:&mdash;</p>
+
+<p>(<i>a</i>) <i>Kirk Session</i> consists of the minister of the parish and the
+&ldquo;ruling elders&rdquo; (who are elected by the session). It has cognizance
+of scandalous offences by laymen and punishes them
+by deprivation of religious privileges. It does not judge ministers
+(Brodie-Innes, <i>Comparative Principles of the Laws of England
+and Scotland</i>, 1903, p. 144).</p>
+
+<p>(<i>b</i>) The <i>Presbytery</i> has jurisdiction, partly appellate and
+partly original, over a number of parishes. There are now eighty-four
+presbyteries. These courts consist of every parochial
+minister or professor of divinity of any university within the
+limits, and of an elder commissioned from every kirk session.
+A minister is elected to preside as moderator. These courts
+judge ministers in first instance for scandalous conduct. As
+civil courts they judge in first instance all questions connected
+with glebes and the erection and repair of churches and manses.
+They regulate matters concerning public worship and ordinances,
+and have appellate jurisdiction from the kirk session.</p>
+
+<p>(<i>c</i>) The <i>Provincial Synod</i> consists of a union of three or more
+presbyteries with the same members. There are now sixteen.
+They meet twice a year to hear appeals from presbyteries. No
+appeal can go direct to the General Assembly, <i>omisso medio</i>,
+unless the presbytery have so expressly directed, or unless there
+be no meeting of synod after the decision of the presbytery
+before the meeting of General Assembly.</p>
+
+<p>(<i>d</i>) The <i>General Assembly</i> is the supreme ecclesiastical court
+of this system. It meets annually. The king&rsquo;s &ldquo;lord high
+commissioner&rdquo; attends the sittings; but does not intervene
+or take part in the court&rsquo;s decisions. The court consists of
+ministers and elders, elected from the presbyteries in specified
+proportions, and of commissioners from the four universities,
+the city of Edinburgh and the royal burghs. The Presbyterian
+Church in India sends one minister and one elder. The whole
+Assembly consists of 371 ministers and 333 elders. The jurisdiction
+is entirely appellate. The Assembly appoints a commission
+to exercise some of its functions during the intervals of
+its session. To this commission may be referred the cognizance
+of particular matters.</p>
+
+<p>Questions of <i>patronage</i> now (by 37 &amp; 38 Vict. c. 82) belong to
+the Church courts; but not questions of <i>lapse</i> or <i>stipend</i>. Seats,
+seat rents, pews, the union and disjunction of parishes and
+formation of district parishes are of secular jurisdiction. Questions
+of tithes (or &ldquo;teinds&rdquo;) and ministers&rsquo; stipends were referred
+to commissioners by acts of the Scots parliaments beginning in
+1607. The commissioners of teinds became a species of ecclesiastical
+court. By Scots act of 1707, c. 9, their powers were
+transferred to the judges of the court of session, who now constitute
+a &ldquo;teind court&rdquo; (Brodie-Innes, <i>op. cit.</i> pp. 138, 139).
+Matrimonial matters and those relating to wills and succession
+(called in Scotland &ldquo;consistorial&rdquo; causes) were in 1563 taken
+from the old bishops&rsquo; courts and given to &ldquo;commissaries&rdquo;
+appointed by the crown with an appeal to the court of session,
+which by act 1609, c. 6, was declared the king&rsquo;s great consistory.
+They have remained matters of secular jurisdiction.</p>
+
+<p>The Scots ecclesiastical courts are entitled to the assistance of
+the secular courts to carry out their jurisdiction by &ldquo;due assistance.&rdquo;
+Within the limits of their jurisdiction they are supreme.
+But if a court go outside its jurisdiction, or refuse to exercise
+powers conferred on it by law, the civil court may &ldquo;reduce&rdquo;
+(<i>i.e.</i> set aside) the sentence and award damages to the party
+aggrieved.</p>
+
+<p>With the Reformation in the 16th century, Church courts
+properly speaking disappeared from the non-episcopal
+religious communities which were established in
+<span class="sidenote">Protestant continental European states.</span>
+Holland, in the Protestant states of Switzerland and
+of Germany, and in the then non-episcopal countries
+of Denmark and Norway.</p>
+
+<p>Discipline over ministers and other office-bearers was exercised
+by administrative methods in the form of trials before consistories
+or synods. To this extent ecclesiastical jurisdiction is
+still exercised in these countries. Consistories and synods have
+<span class="pagenum"><a name="page864" id="page864"></a>864</span>
+exercised discipline of a penitential kind over their lay members;
+but in later times their censures have generally ceased to carry
+temporal consequences. Ecclesiastical jurisdiction on the civil
+side for the trial of causes soon disappeared. Heresy has been
+treated as a crime to be tried in and punished by the ordinary
+courts of the country, as in the cases of Servetus (<i>q.v.</i>) and
+Grotius (<i>q.v.</i>).</p>
+
+<p>For the episcopal churches of Sweden and Finland the first
+constitution or &ldquo;Church order&rdquo; was formed in 1571. It provided
+for the visitation of the clergy by the bishop, and for the
+power of the clergy to exclude their lay folk from the Holy
+Communion, subject to appeal to the bishop. Both minor and
+major excommunication had been in use, and for a long time
+public penance was required. The procedure underwent great
+modification in 1686; but public penance was not taken away
+till 1855, and then confession to and absolution by the priest in
+the presence of witnesses was still required. Civil jurisdiction in
+causes appears to have been given up early (Cornelius, <i>Svenska
+Kirkaus Historia</i>, Upsala, 1875, pp. 146, 186, 189, 285).</p>
+
+<p>Over the rest of western continental Europe and in the colonies
+of Spain, Portugal and France, ecclesiastical jurisdiction remained
+generally in the state which we have already described
+till near the end of the 18th century. The council of
+<span class="sidenote">Roman Catholic countries.</span>
+Trent took away the jurisdiction of archdeacons in
+marriage questions. The testamentary jurisdiction
+disappeared (as already stated) in France. Disputed cases of
+contract were more often tried in the secular courts. Recourse
+to the secular prince by way of <i>appel comme d&rsquo;abus</i>, or otherwise,
+became more frequent and met with greater encouragement.
+Kings began to insist upon trying ecclesiastics for treason or
+other political crimes in secular courts. So under the advice of
+his minister (the marquis of Pombal), King Joseph of Portugal in
+1759-1760 claimed that the pope should give him permission to
+try in all cases clerics accused of treason, and was not content
+with the limited permission given to try and execute, if guilty,
+the Jesuits then accused of conspiring his death (<i>Life of Pombal</i>,
+by Count da Carnota, 1871, pp. 128, 141). But there was no
+sudden change in the position of the courts Christian till the
+French Revolution.</p>
+
+<p>In France a law of the Revolution (September 1790) purported
+to suppress all ecclesiastical jurisdictions. On the re-establishing
+of the Catholic religion on the basis of the new Concordat,
+promulgated 18 Germinal, year X. (April 8, 1802), no express
+provision was made for ecclesiastical jurisdictions; but several
+bishops did create new ecclesiastical tribunals, &ldquo;officialities&rdquo;
+(Migne, <i>Dict. de droit canon.</i>, <i>s.v.</i>). The government in some
+cases recognized these tribunals as capable of judging ecclesiastical
+causes (Migne, <i>ubi sup.</i>). In 1810 the diocesan official of
+Paris entertained the cause between Napoleon and Josephine,
+and pronounced a decree of nullity (Migne, <i>ubi sup.</i> <i>s.v.</i>
+&ldquo;Causes&rdquo;). Such litigation as still continued before the spiritual
+forum was, however, confined (save in the case of the matrimonial
+questions of princes) to the professional conduct of the clergy.</p>
+
+<p>Such neighbouring countries as were conquered by France or
+revolutionized after her pattern took the same course of suppressing
+their ecclesiastical jurisdictions. After 1814, some of
+these jurisdictions were revived. But the matter is now determined
+for all countries which have adopted codes, whether after
+the pattern of the Code Napoléon or otherwise. These countries
+have created a hierarchy of temporal courts competent to deal
+with every matter of which law takes cognizance, and a penal
+code which embraces and deals with all crimes or delicts which
+the state recognizes as offences. Hence, even in countries where
+the Roman Church is established, such as Belgium, Italy, the
+Catholic states of Germany and cantons of Switzerland, most
+of the Latin republics of America, and the province of Quebec,
+and <i>a fortiori</i> where this Church is not established, there is
+now no discipline over the laity, except penitential, and no jurisdiction
+exercised in civil suits, except possibly the matrimonial
+questions of princes (of which there was an example in the
+case of the reigning prince of Monaco). In Spain causes of
+nullity and divorce <i>a thoro</i>, in Portugal causes of nullity between
+Catholics, are still for the court Christian. In Peru, the old
+ecclesiastical matrimonial jurisdiction substantially remains
+(Lehr, <i>Le Mariage dans les principaux pays</i>, 1899, arts. 362, 797,
+772, 781). Otherwise these three countries are Code countries.
+In Austria, the ancient ecclesiastical jurisdiction was taken away
+by various acts of legislation from 1781 to 1856; even voluntary
+jurisdiction as to dispensations. The Concordat of 1856 and
+consequent legislation restored matrimonial jurisdiction to the
+courts Christian over marriages between Roman Catholics. In
+1868 this was taken away. The Austrian bishops, however,
+maintain their tribunals for spiritual purposes, and insist that
+such things as divorce <i>a vinculo</i> must be granted by their authority
+(Aichner, <i>Compendium juris ecclesiastici</i>, pp. 551-553).</p>
+
+<p>By consent and submission of her members, the Roman Church
+decides <i>in foro conscientiae</i> questions of marriage, betrothal and
+legitimacy everywhere; but no temporal consequences follow
+except in Spain, Portugal and Peru.</p>
+
+<p>The position in France was the same as that in Belgium, Italy,
+&amp;c., till 1906, when the Church ceased to be established. The
+only Latin countries in which conflict has not arisen appear to
+be the principality of Andorra and the republic of San Marino
+(Giron y Areas, <i>Situación jurídica de la Iglesia Católica</i>, Madrid,
+1905, p. 173 et seq.).</p>
+
+<p>Even as to the discipline of the Roman clergy it is only in
+certain limited cases that one can speak of ecclesiastical jurisdiction.
+Bishops and beneficed incumbents (<i>curés</i>) must be regularly
+tried; and where the Church is established the canonical courts
+are recognized. But the majority of parishes are served by mere
+<i>desservants</i> or <i>vicaires</i>, who have no rights and can be recalled
+and dismissed by mere administrative order without trial (Migne,
+<i>ubi sup.</i> <i>s.v.</i> &ldquo;Inamovibilité,&rdquo; &ldquo;Desservants&rdquo;).</p>
+
+<p>The Napoleonic legislation re-established the <i>appel comme
+d&rsquo;abus</i> (&ldquo;<i>Articles organiques</i>,&rdquo; art. 6). The recourse was now to
+the council of state (see Migne, <i>ubi supra</i>, &ldquo;Officialité&rdquo;). But
+the revocation of a <i>desservant</i>, and the forbidding him the execution
+of his ministry in the diocese, was not a case in which the
+council of state would interfere (Migne, <i>ubi sup.</i> &ldquo;Appel comme
+d&rsquo;abus,&rdquo; &ldquo;Conseil d&rsquo;état&rdquo;).</p>
+
+<p>In those provinces of the Anglican communion where the
+Church is not established by the state, the tendency is
+<span class="sidenote">Jurisdiction in Anglican communion.</span>
+not to attempt any external discipline over the laity;
+but on the other hand to exercise consensual jurisdiction
+over the clergy and office-bearers through courts
+nearly modelled on the old canonical patterns.</p>
+
+<p>In the Roman communion, on the other hand, both where
+the Church is established and where it is not, the tendency is
+to reduce the status of <i>curé</i> to that of <i>desservant</i>, and to
+deal with all members of the priestly or lower orders
+<span class="sidenote">Modern jurisdiction of Church of Rome.</span>
+by administrative methods. This practice obtains in
+all missionary countries, <i>e.g.</i> Ireland and also in
+Belgium (S.B. Smith, <i>Elements of Ecclesiastical Law</i>,
+New York, i. 197 et seq.; p. 403 et seq.; Tauber, <i>Manuale
+juris canonici</i>, Sabariae, 1904, p. 277). In the United States,
+the 3rd plenary council of Baltimore in 1884 provided that one
+rector out of ten should be irremovable (Smith, <i>op. cit.</i> i. 197,
+419). In England there are few Roman &ldquo;benefices&rdquo; (E.
+Taunton, <i>Law of the Church</i>, London, 1906, <i>s.v.</i> &ldquo;Benefice&rdquo;).
+A <i>desservant</i> has an informal appeal, by way of recourse, to the
+metropolitan and ultimately to the pope (Smith, <i>op. cit.</i> p. 201).
+The bishop&rsquo;s &ldquo;official&rdquo; is now universally called his vicar-general
+(except in France, where sometimes an <i>official</i> is appointed
+<i>eo nomine</i>), and generally exercises both voluntary and contentious
+jurisdiction (<i>op. cit.</i> i. 377). As of old, he must be at
+least tonsured and without a wife living. At the Vatican
+Council, a desire was expressed that he should be a priest (<i>ib.</i>).
+He should be a doctor in theology or a licentiate in canon law
+(<i>ib.</i> p. 378). Whether a bishop is bound to appoint a vicar-general
+is still disputed (<i>ib.</i> p. 380; cf. <i>supra</i>; <i>contra</i>, Bouix, <i>Inst. Juris
+Canon. De Judic.</i> i. 405). In 1831 the pope enacted that in
+all the dioceses of the then Pontifical States, the court of first
+instance for the criminal causes of ecclesiastics should consist of
+the ordinary and four other judges. In the diocese of Rome,
+<span class="pagenum"><a name="page865" id="page865"></a>865</span>
+the court of the cardinal vicar-general consists of such vicar-general
+and four other prelates (Smith, <i>ubi supra</i>). In the
+Roman communion in England and the United States, there
+are commissions of investigation appointed to hear in first
+instance the criminal causes of clerks. They consist of five, or at
+least three, priests nominated by the bishop in and with the
+advice of the diocesan synod. In the United States, since 1884,
+the bishop presides on these commissions. They report their
+opinions to the bishop, who passes final sentence (<i>ib.</i> ii. 129-131).</p>
+
+<p>&ldquo;Exemptions&rdquo; now include all the regular religious orders,
+<i>i.e.</i> those orders which have solemn vows. Over the members of
+these orders their superiors have jurisdiction and not the bishop.
+Otherwise if they live out of their monastery, or even within that
+enclosure so notoriously offend as to cause scandal. In the first
+case, they may be punished by the ordinary of the place, acting as
+delegate of the pope without <span class="correction" title="amended from speical">special</span> appointment (<i>Conc. Trid.
+Sess.</i> vi. c. 3). In the second case, the bishop may require the
+superior to punish within a certain time and to certify the
+punishment to him; in default he himself may punish (<i>Conc.
+Trid. Sess.</i> xxv. c. 14, cf. Smith, <i>op. cit.</i> i. 204-206). So,
+regulars having cure of souls are subject to the jurisdiction of the
+bishop in matters pertaining thereto (<i>ib.</i> p. 206). The exemption
+of regular religious orders may be extended to religious
+societies without solemn vows by special concession of the pope,
+as in the case of the Passionists and Redemptorists (<i>ib.</i> p. 205;
+Sanguineti, <i>Juris ecc. inst.</i>, Rome, 1800, pp. 393, 394).</p>
+
+<p>Appeal lies, in nearly all cases, to the metropolitan (Smith,
+<i>op. cit.</i> pp. 219-223). Metropolitans usually now have a metropolitan
+tribunal distinct from their diocesan court (<i>ib.</i> ii. 141),
+but constructed on the same lines, with the metropolitan as judge
+and his vicar-general as vice-judge. In some &ldquo;missionary&rdquo;
+dioceses, the metropolitan, <i>qua</i> metropolitan, has a separate
+commission of investigation, to try the criminal causes of
+clerks, sentence being passed by himself or his vicar-general (<i>ib.</i>
+p. 142).</p>
+
+<p>The next step in the hierarchy, that of &ldquo;primates&rdquo; (<i>supra</i>),
+has &ldquo;in the present state of the Church&rdquo; ceased to exist for our
+purpose (Sanguineti, <i>op. cit.</i> p. 334), as a result of Tridentine legislation.
+The only appellate jurisdiction from the metropolitans is
+the Roman See. To it also lies a direct appeal from the court of
+first instance, <i>omisso medio</i> (Smith, <i>op. cit.</i> i. 224). The pope&rsquo;s
+immediate and original jurisdiction in every diocese is now
+expressly affirmed by the Vatican Council (<i>ib.</i> p. 239). That
+original jurisdiction he reserves exclusively to himself in <i>causis
+majoribus</i> (<i>ib.</i> pp. 249-250). These are (1) causes relating to
+elections, translations and deprivations of, and criminal prosecutions
+against, bishops, and (2) the matrimonial cases of princes
+(Taunton, <i>op. cit. s.v.</i> &ldquo;Cause&rdquo;).</p>
+
+<p>In the Eastern Church, the early system of ecclesiastical
+judicature long continued. But a sacred character was ascribed
+to the emperors. They are &ldquo;anointed lords like the
+bishops&rdquo; (Balsamon, in <i>Conc. Ancyr. Can.</i> xii., representing
+<span class="sidenote">Eastern Church.</span>
+the view of the 12th and 13th centuries).
+Bishops were often deposed by administrative order of the
+emperor; synods being expected afterwards to confirm, or rather
+accept, such order. The germ of this dealing with a <i>major causa</i>
+may be found in the practice of the Arian emperors in the 4th
+century. The cause of Ignatius and Photius was dealt with in
+the 9th century by various synods; those in the East agreeing
+with the emperor&rsquo;s view for the time being, while those in the
+West acted with the pope. (The details are in Mansi, <i>Conc. in
+locis</i>, and in Hefele, <i>Conc. in locis</i>, more briefly. They are summarized
+in Landon, <i>Manual of Councils</i>, <i>s.v.</i> &ldquo;Constantinople,&rdquo;
+&ldquo;Rome,&rdquo; and in E.S. Foulkes, <i>Manual of Ecclesiastical History</i>,
+<i>s.v.</i> &ldquo;Century IX.&rdquo;) Since these transactions patriarchs have been
+deposed by the Byzantine emperors; and the Turkish sultans
+since the 15th century have assumed to exercise the same
+prerogative.</p>
+
+<p>The spiritual courts in the East have permanently acquired
+jurisdiction in the matrimonial causes of baptized persons;
+the Mahommedan governments allowing to Christians a personal
+law of their own. The patriarch of Constantinople is enabled
+to exercise an extensive criminal jurisdiction over Christians
+(Neale, <i>Hist. of the Eastern Church</i>, i. 30, 31).</p>
+
+<p>The empire of Russia has in the matter of ecclesiastical jurisdiction
+partly developed into other forms, partly systematized
+4th century and later Byzantine rules. The provincial system
+does not exist; or it may be said that all Russia is one province.
+An exception should be made in the case of Georgia, which is
+governed by an &ldquo;exarch,&rdquo; with three suffragans under him.
+In the remainder of the empire the titles of metropolitan, save
+in the case of the metropolitan of all Russia, and of archbishop,
+were and are purely honorary, and their holders have merely
+a diocesan jurisdiction (see Mouravieff, <i>History of the Russian
+Church</i>, translated Blackmore, 1842, translator&rsquo;s notes at pp. 370,
+390, 416 et seq.). So in Egypt the bishop or &ldquo;pope&rdquo; (afterwards
+patriarch) of Alexandria was the only true metropolitan (Neale,
+<i>History of the Eastern Church</i>, Gen. Introd. vol. i. p. 111). The
+metropolitan of Russia from the time of the conversion (<span class="scs">A.D.</span> 988)
+settled at Kiev, and his province was part of the patriarchate of
+Constantinople, and appeals lay to Constantinople. Many such
+appeals were taken, notably in the case of Leon, bishop of Rostov
+(Mouravieff, <i>op. cit.</i> p. 38). The metropolitical see was for a
+short time transferred to Vladimir and then finally to Moscow
+(Mouravieff, chs. iv., v.). After the taking of Constantinople in
+1452, the Russian metropolitans were always chosen and consecrated
+in Russia, appeals ceased, and Moscow became <i>de facto</i>
+autocephalous (Joyce, ubi sup. p. 379; Mouravieff, <i>op. cit.</i>
+p. 126). The tsar Theodore in 1587 exercised the power of the
+Byzantine emperors by deposing the metropolitan, Dionysius
+Grammaticus (Mouravieff, p. 125). In 1587 the see of Moscow
+was raised to patriarchal rank with the consent of Constantinople,
+and the subsequent concurrence of Alexandria, Antioch and
+Jerusalem (<i>ib.</i> c. vi.). Moscow became the final court, in theory,
+as it had long been in practice. Certain religious houses, however,
+had their own final tribunals and were &ldquo;peculiars,&rdquo; exempt from
+any diocesan or patriarchal jurisdiction for at least all causes
+relating to Church property (<i>ib.</i> p. 131).</p>
+
+<p>The subject matter of ecclesiastical jurisdiction in Russia
+during the whole patriarchal period included matrimonial and
+testamentary causes, inheritance and sacrilege, and many questions
+concerning the Church domains and Church property, as well as
+spiritual offences of clergy and laity (<i>ib.</i>). The bishops had
+consistorial courts; the patriarchs, chanceries and consistories
+(<i>ib.</i>). Bishops were judged in synod (see, <i>e.g.</i> the case of the
+archbishop of Polotsk in 1622, <i>ib.</i> p. 179) and only lawfully
+judged in synod (<i>ib.</i> p. 215).</p>
+
+<p>Clerks and the dependants of the metropolitan (afterwards
+the patriarch) appear to have been immune from secular jurisdiction,
+except in the case of crimes against life, from the time of
+Ivan the Terrible (<i>ib.</i> pp. 180-181). The tsar Michael, in the
+earlier 17th century, confirmed these immunities in the case of
+the clergy of the patriarch&rsquo;s own diocese, but provided that in
+country places belonging to his diocese, monasteries, churches and
+lands should be judged in secular matters by the Court of the
+Great Palace, theoretically held before the tsar himself (<i>ib.</i> p. 181).
+This tsar limited the &ldquo;peculiar&rdquo; monasteries to three, and gave
+the patriarch jurisdiction over them (<i>ib.</i>). The next tsar, Alexis,
+however, by his code instituted a &ldquo;Monastery Court,&rdquo; which was
+a secular tribunal composed of laymen, to judge in civil suits
+against spiritual persons, and in matters arising out of their
+manors and properties (<i>ib.</i> p. 193). This court was not in operation
+during the time when the patriarch Nikon was also in effect
+first minister; but upon his decline exercised its full jurisdiction
+(<i>ib.</i> p. 216). Nikon was himself tried for abdicating his see, causing
+disorder in the realm, oppression and violence, first before a synod
+of Moscow composed of his suffragans and some Greek bishops,
+and afterwards before another synod in which sat the patriarchs
+of Alexandria and Antioch, the metropolitans of Servia and
+Georgia, the archbishops of Sinai and Wallachia, and the metropolitans
+of Nice, Amasis, Iconium, Trebizond, Varna and Scio,
+besides the Russian bishops. This synod in 1667 deposed Nikon,
+degraded him from holy orders, and sentenced him to perpetual
+penance in a monastery (<i>ib.</i> pp. 220-232). The next tsar, Theodore,
+<span class="pagenum"><a name="page866" id="page866"></a>866</span>
+suppressed the secular &ldquo;monastery court,&rdquo; and directed that all
+suits against spiritual persons should proceed only in the patriarchal
+&ldquo;court of requests&rdquo; (<i>ib.</i> p. 264). There was, however,
+a species of <i>appel comme d&rsquo;abus</i>. Causes could be evoked to the
+tsar himself, &ldquo;when any partiality of the judges in any affair in
+which they themselves were interested was discovered&rdquo; (<i>ib.</i>).</p>
+
+<p>The old system was swept away by Peter the Great, who
+settled ecclesiastical jurisdiction substantially on its present
+basis. The patriarchate was abolished and its jurisdiction
+transferred by a council at St Petersburg in 1721 to a Holy
+Governing Synod. The change was approved by the four
+patriarchs of the East in 1723 (<i>ib.</i> chs. xv.-xvii.). Peter permanently
+transferred to the secular <i>forum</i> the testamentary
+jurisdiction and that concerning inheritance, as also questions of
+&ldquo;sacrilege&rdquo; (<i>ib.</i> p. 264). As the result of a long series of legislation,
+beginning with him and ending with Catherine II., all church
+property of every kind was transferred to secular administration,
+allowances, according to fixed scales, being made for ministers,
+monks and fabrics (<i>op. cit.</i> translator&rsquo;s appendix i. p. 413 et seq.).
+There remain to the spiritual courts in Russia the purely ecclesiastical
+discipline of clerks and laity and matrimonial causes.</p>
+
+<p>The court of first instance is the &ldquo;consistorial court&rdquo; of the
+bishop. This consists of a small body of ecclesiastics. Its
+decisions must be confirmed by the bishop (<i>op. cit.</i> translator&rsquo;s
+appendix ii. pp. 422-423). In the more important causes, as
+divorce (<i>i.e.</i> <i>a vinculo</i>), it only gives a provisional decision,
+which is reported by the bishop, with his own opinion, for final
+judgment, to the Most Holy Governing Synod.</p>
+
+<p>The governing synod is the final court of appeal. It consists
+of a small number of bishops and priests nominated by the tsar,
+and is assisted by a &ldquo;procurator,&rdquo; who is a layman, who explains
+to it the limits of its jurisdiction and serves as the medium of
+communication between it and the autocrat and secular
+authorities. It deals with the secular crimes of spiritual persons,
+if of importance and if not capital (these last being reserved
+for the secular forum), and with heresy and schism. It is the
+only court which can try bishops or decree divorce. The tsar
+formally confirms its judgments; but sometimes reduces
+penalties in the exercise of the prerogative of mercy (see Mouravieff,
+<i>op. cit.</i> ch. xvii. translator&rsquo;s app. ii.).</p>
+
+<p>The governing synod now sits at St Petersburg, but appoints
+delegated commissions, with a portion of its jurisdiction, in
+Moscow and Georgia. The latter commission is presided over
+by the &ldquo;exarch&rdquo; (<i>supra</i>).</p>
+
+<p>Since the War of Independence, the kingdom of Greece has
+been ecclesiastically organized after the model of Russia, as one
+autocephalous &ldquo;province,&rdquo; separated from its old patriarchate
+of Constantinople, with an honorary metropolitan and honorary
+archbishops (Neale, <i>op. cit.</i> Gen. Introd. vol. i.). The Holy
+Synod possesses the metropolitical jurisdiction. It sits at
+Athens. The metropolitan of Athens is president, and there are
+four other members appointed by the government in annual
+rotation from the senior bishops. There is attached to it a government
+commissioner, with no vote, but affixing his signature to
+the synodical judgments (Joyce, <i>op. cit.</i> p. 35).</p>
+
+<p>The subject matter of the jurisdiction of Hellenic courts
+Christian seems to be confined to strictly spiritual discipline,
+mainly in regard to the professional misconduct of the clergy.
+Imprisonment may be inflicted in these last cases (<i>ib.</i>). All
+matrimonial causes are heard by the secular tribunals (Lehr,
+<i>op. cit.</i> sec. 587).</p>
+
+<p>The bishop&rsquo;s consistorial court, consisting of himself and four
+priests, has a limited jurisdiction in first instance. Such a court
+can only suspend for seven days unless with the sanction of the
+Holy Synod (Joyce, <i>op. cit.</i>).</p>
+
+<p>The Holy Synod can only inflict temporary suspension, or
+imprisonment for fifteen days, unless with the sanction of the
+King&rsquo;s ministry. Deprivation, or imprisonment for more than
+two months, requires the approval of the king (<i>ib.</i>). The king
+or the ministry do not, however, rehear the cause by way of
+appeal, but merely restrain severity of sentence (<i>ib.</i>).</p>
+
+<p>The Church of Cyprus has been autocephalous since at any rate
+the oecumenical synod of Ephesus in 431. The episcopate now
+consists of an archbishop and three suffragans (Hackett, <i>Orthodox
+Church in Cyprus</i>, 1901, ch. v. <i>et passim</i>). The final court is
+the island synod, which consists of the archbishop, his suffragans
+and four dignified priests. It has original and exclusive cognizance
+of causes of deposition of bishops (<i>op. cit.</i> pp. 260, 262).</p>
+
+<p>Each bishop is assisted by at least two officers with judicial
+or quasi-judicial powers, the &ldquo;archimandrite&rdquo; who adjudicates
+upon causes of revenue and the archdeacon who adjudicates on
+questions between deacons (<i>op. cit.</i> pp. 272-273). The &ldquo;exarch&rdquo;
+of the archbishop, who is a dignitary but not a bishop, has a seat
+in the provincial synod.</p>
+
+<p>In the Balkan States, the system&mdash;inherited from Byzantine
+and Turkish times&mdash;of ecclesiastical jurisdictions prevails, except
+that they are now autocephalous, and independent of the patriarch
+of Constantinople. Matrimonial causes in Servia are of ecclesiastical
+cognizance (Lehr, <i>op. cit.</i> sect. 901).</p>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;St Augustine, <i>Epistles</i>; <i>Codex Theodosianus</i>,
+edited by Th. Mommsen and P.M. Meyer (1905); <i>Code and Novells
+of Emperor Justinian</i>, ed. J. Gothofredus (1665); T. Balsamon,
+&ldquo;In Conc. Ancyr.&rdquo; in the <i>Corpus juris canonici</i> (1879-1881);
+&ldquo;<i>Hostiensis</i>&rdquo; <i>Super Decretum</i>; W. Lyndwood, <i>Provinciale</i> (Oxford,
+1679); Sir A. Fitzherbert, <i>Natura brevium</i> (1534); Sir T. Ridley,
+<i>View of the Civile and Ecclesiastical Law</i> (1607); J. Ayliffe, <i>Parergon
+juris ecclesiastici</i> (1726); J. Godolphin, <i>Abridgement of the Laws
+Ecclesiastical</i> (London, 1687); E. Gibson, <i>Codex juris ecclesiastici</i>
+(Oxford, 1761); D. Covarruvias, <i>Opera omnia</i> (Antwerp, 1638);
+Jean Hardouin, <i>Concilia</i> (1715); J.D. Mansi, <i>Concilia</i> (1759-1798);
+E. Stillingfleet, <i>Ecclesiastical Jurisdiction</i> (1704); L.S. le Nain de
+Tillemont, <i>Mémoires pour servir à l&rsquo;histoire ecclésiastique</i> (1701-1712);
+P.T. Durand de Maillane, <i>Dictionnaire du droit canonique</i> (1761);
+<i>Dictionnaire ecclésiastique et canonique</i>, par une société de religieux
+(Paris, 1765); Z.B. van Espen, <i>Jus ecclesiasticum universum</i>
+(Louvain, 1720), <i>De recursu ad Principem, observationes in Concilium
+Lateranense iv.</i>; L. Thomassin, <i>Vetus et nova disciplina
+ecc.</i> (1705-1706); W. Beveridge, <i>Synodicon</i> (Oxford, 1672);
+J.A.S. da Carnota, <i>Life of Pombal</i> (1843); J.P. Migne, <i>Dictionnaire
+de droit canon.</i> (Paris, 1844); R. Keith, <i>History of the Scottish
+Bishops</i> (Edinburgh, 1824); P.N. Vives y Cebriá, <i>Usages y demas
+derechos de Cataluña</i> (1832); C.A. Cornelius, <i>Svenska Kyrkaus
+Historia</i> (Upsala, 1875); Mouravieff, <i>History of the Russian Church</i>
+(trans. Blackmore, 1842); Ffoulkes, <i>Manual of Ecclesiastical History</i>
+(1851); E.H. Landon, <i>Manual of Councils of the Church</i> (1893);
+W.H. Hale, <i>Precedents in Criminal Cases</i> (London, 1847); E.B.
+Pusey, <i>Councils of the Church</i> (Oxford, 1857); C.J. von Hefele,
+<i>Conciliengeschichte</i> (Freiburg, 1855-1890); M. Gaudry, <i>Traité de
+la législation des cultes</i> (Paris, 1854); W. Stubbs, <i>Select Charters</i>
+(Oxford, 1895); A.W. Haddan and W. Stubbs, <i>Councils and
+Ecclesiastical Documents</i> (Oxford, 1869); A.J. Stephens, <i>Ecclesiastical
+Statutes</i> (1845); H.C. Rothery, <i>Return of Cases before Delegates</i>
+(1864); J.W. Joyce, <i>The Sword and the Keys</i> (2nd ed., 1881);
+<i>Report of Ecclesiastical Courts Commission</i> (1888); P. Fournier, <i>Les
+Officialités au moyen âge</i> (1880); S.B. Smith, <i>Elements of Ecclesiastical
+Law</i> (New York, 1889-1890); S. Sanguineti, <i>Juris ecc. inst.</i> (Rome,
+1890); J.F. Stephen, <i>History of the Criminal Law of England</i>
+(London, 1883); Pollock and Maitland, <i>History of English Law
+before Edward I.</i> (1898); F.W. Maitland, <i>Roman Canon Law in
+the Church of England</i> (1898); R. Owen, <i>Canon Law</i> (1884); Sir
+R.J. Phillimore, <i>Ecclesiastical Law</i> (2nd ed., 1895); J.W. Brodie-Innes,
+<i>Comparative Principles of the Laws of England and Scotland</i>
+(1903); R.B. Merriman, <i>Life and Letters of Thomas Cromwell</i> (1902);
+S. Aichner, <i>Compendium juris ecclesiast.</i> (8th ed., Brixen, 1905,
+especially in regard to Austro-Hungarian Empire); J. Hackett,
+<i>History of the Orthodox Church in Cyprus</i> (1901); Tauber, <i>Manuale
+juris canonici</i> (1906); E.L. Taunton, <i>Law of the Church</i> (London,
+1906); <i>Report of Royal Commission on Ecclesiastical Discipline</i>
+(1906).</p>
+</div>
+<div class="author">(W. G. F. P.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIASTICAL LAW,<a name="ar119" id="ar119"></a></span> in its broadest sense, the sum of
+the authoritative rules governing the Christian Church, whether
+in its internal polity or in its relations with the secular power.
+Since there are various churches, widely differing alike in their
+principles and practice, it follows that a like difference exists
+in their ecclesiastical law, which is the outcome of their corporate
+consciousness as modified by their several relations to the
+secular authority. At the outset a distinction must be made
+between churches which are &ldquo;established&rdquo; and those that are
+&ldquo;free.&rdquo; The ecclesiastical laws of the latter are, like the rules
+of a private society or club, the concern of the members of the
+church only, and come under the purview of the state only in
+so far as they come in conflict with the secular law (<i>e.g.</i> polygamy
+among the Mormons, or violation of the trust-deeds under which
+<span class="pagenum"><a name="page867" id="page867"></a>867</span>
+the property of a church is held). In the case of &ldquo;established&rdquo;
+Churches, on the other hand, whatever the varying principle
+on which the system is based, or the difference in its practical
+application, the essential conditions are that the ecclesiastical
+law is also the law of the land, the decisions of the church courts
+being enforced by the civil power. This holds good both of the
+Roman Catholic Church, wherever this is recognized as the
+&ldquo;state religion,&rdquo; of the Oriental Churches, whether closely
+identified with the state itself (as in Russia), or endowed with
+powers over particular nationalities within the state (as in the
+Ottoman empire), and of the various Protestant Churches
+established in Great Britain and on the continent of Europe.</p>
+
+<p>Writers on the theory of ecclesiastical law, moreover, draw
+a fundamental distinction between that of the Church of Rome
+and that of the Protestant national or territorial Churches.
+This distinction is due to the claim of the Roman Catholic Church
+to be the <i>only</i> Church, her laws being thus of universal obligation;
+whereas the laws of the various established Protestant Churches
+are valid&mdash;at least so far as legal obligation is concerned&mdash;only
+within the limits of the countries in which they are established.
+The practical effects of this distinction have been, and still are,
+of enormous importance. The Roman Catholic Church, even
+when recognized as the state religion, is nowhere &ldquo;established&rdquo;
+in the sense of being identified with the state, but is rather an
+<i>imperium in imperio</i> which negotiates on equal terms with the
+state, the results being embodied in concordats (<i>q.v.</i>) between
+the state and the pope as head of the Church. The concordats
+are of the nature of truces in the perennial conflict between the
+spiritual and secular powers, and imply in principle no surrender
+of the claims of the one to those of the other. Where the Roman
+Catholic Church is not recognized as a state religion, as in the
+United States or in the British Islands, she is in the position of
+a &ldquo;free Church,&rdquo; her jurisdiction is only <i>in foro conscientiae</i>,
+and her ecclesiastical laws have no validity from the point of
+view of the state. On the other hand, the root principle of the
+ecclesiastical law of the established Protestant Churches is the
+rejection of alien jurisdiction and the assertion of the supremacy
+of the state. The theory underlying this may vary. The
+sovereign may be regarded, as in the case of the Russian emperor
+or of the English kings from the Reformation to the Revolution,
+as the vicar of God in all causes spiritual as well as temporal
+within his realm. As the first fervent belief in the divine right
+of kings faded, however, a new basis had to be discovered for
+a relation between the spiritual and temporal powers against
+which Rome had never ceased to protest. This was found in
+the so-called &ldquo;collegial&rdquo; theory of Church government (<i>Kollegialsystem</i>),
+which assumed a sort of tacit concordat between the state
+and the religious community, by which the latter vests in the
+former the right to exercise a certain part of the <i>jus in sacra</i>
+properly inherent in the Church (see <span class="sc"><a href="#artlinks">Pufendorf, Samuel</a></span>).
+This had great and lasting effects on the development of the
+theory of Protestant ecclesiastical law on the continent of
+Europe. In England, on the other hand, owing to the peculiar
+character of the Reformation there and of the Church that was
+its outcome, no theory of the ecclesiastical law is conceivable
+that would be satisfactory at once to lawyers and to all schools
+of opinion within the Church. This has been abundantly proved
+by the attitude of increasing opposition assumed by the clergy,
+under the influence of the Tractarian movement, towards the
+civil power in matters ecclesiastical, an attitude impossible to
+justify on any accepted theory of the Establishment (see below).</p>
+
+<p>Protestant ecclesiastical law, then, is distinguished from that
+of the Roman Catholic Church (1) by being more limited in its
+scope, (2) by having for its authoritative source, not the Church
+only or even mainly, but the Church in more or less complete
+union with or subordination to the State, the latter being considered,
+equally with the Church, as an organ of the will of God.
+The ecclesiastical law of the Church of Rome, on the other hand,
+whatever its origin, is now valid only in so far as it has the
+sanction of the authority of the Holy See. And here it must
+be noted that the &ldquo;canon law&rdquo; is not identical with the &ldquo;ecclesiastical
+law&rdquo; of the Roman Catholic Church. By the canon law
+is meant, substantially, the contents of the <i>Corpus juris canonici</i>,
+which have been largely superseded or added to by, <i>e.g.</i> the
+canons of the council of Trent and the Vatican decrees. The
+long projected codification of the whole of the ecclesiastical
+law of the Church of Rome, a work of gigantic labour, was not
+taken in hand until the pontificate of Pius X. (See also <span class="sc"><a href="#artlinks">Canon
+Law</a></span> and <span class="sc"><a href="#artlinks">Ecclesiastical Jurisdiction</a></span>.)</p>
+
+<p>The ecclesiastical law of England is in complete dependence
+upon the authority of the state. The Church of England cannot
+be said, from a legal point of view, to have a corporate existence
+or even a representative assembly. The Convocation of York and
+the Convocation of Canterbury are provincial assemblies possessing
+no legislative or judicial authority; even such purely
+ecclesiastical questions as may be formally commended to their
+attention by &ldquo;letters of business&rdquo; from the crown can only be
+finally settled by act of parliament. The ecclesiastical courts are
+for the most part officered by laymen, whose subordination to
+the archbishops and bishops is purely formal, and the final court
+of appeal is the Judicial Committee of the Privy Council. In
+like manner changes in the ecclesiastical law are made directly
+by parliament in the ordinary course of legislation, and in point
+of fact a very large portion of the existing ecclesiastical law
+consists of acts of parliament.</p>
+
+<p>The sources of the ecclesiastical law of England are thus
+described by Dr. Richard Burn (<i>The Ecclesiastical Law</i>, 9th ed.,
+1842):&mdash;&ldquo;The ecclesiastical law of England is compounded
+of these four main ingredients&mdash;the civil law, the canon law, the
+common law, and the statute law. And from these, digested in
+their proper rank and subordination, to draw out one uniform
+law of the church is the purport of this book. When these laws
+do interfere and cross each other, the order of preference is this:&mdash;&rsquo;The
+civil law submitteth to the canon law; both of these to
+the common law; and all three to the statute law. So that
+from any one or more of these, without all of them together,
+or from all of them together without attending to their comparative
+obligation, it is not possible to exhibit any distinct
+prospect of the English ecclesiastical constitution.&rsquo; Under the
+head of statute law Burn includes &lsquo;the Thirty-nine Articles of
+Religion, agreed upon in Convocation in the year 1562; and in
+like manner the Rubric of the Book of Common Prayer, which,
+being both of them established by Acts of Parliament, are to be
+esteemed as part of the statute law.&rsquo;&rdquo;</p>
+
+<p>The first principle of the ecclesiastical law in England is the
+assertion of the supremacy of the crown, which in the present
+state of the constitution means the same thing as the supremacy
+of parliament. This principle has been maintained ever since
+the Reformation. Before the Reformation the ecclesiastical
+supremacy of the pope was recognized, with certain limitations,
+in England, and the Church itself had some pretensions to
+ecclesiastical freedom. The freedom of the Church is, in fact,
+one of the standing provisions of those charters on which the
+English constitution was based. The first provision of Magna
+Carta is <i>quod ecclesia Anglicana libera sit</i>. By the various enactments
+of the period of the Reformation the whole constitutional
+position of the Church, not merely with reference to the pope
+but with reference to the state, was definitely fixed. The legislative
+power of convocation was held to extend to the clergy
+only, and even to that extent required the sanction and assent
+of the crown. The common law courts controlled the jurisdiction
+of the ecclesiastical courts, claiming to have &ldquo;the exposition of
+such statutes or acts of parliament as concern either the extent
+of the jurisdiction of these courts or the matters depending
+before them. And therefore if these courts either refuse to allow
+these acts of parliament, or expound them in any other sense
+than is truly and properly the exposition of them, the king&rsquo;s
+great courts of common law may prohibit and control them.&rdquo;</p>
+
+<p>The design of constructing a code of ecclesiastical laws was
+entertained during the period of the Reformation, but never
+carried into effect. It is alluded to in various statutes of the
+reign of Henry VIII., who obtained power to appoint a commission
+to examine the old ecclesiastical laws, with a view of
+deciding which ought to be kept and which ought to be abolished;
+<span class="pagenum"><a name="page868" id="page868"></a>868</span>
+and in the meantime it was enacted that &ldquo;such canons,
+institutions, ordinances, synodal or provincial or other ecclesiastical
+laws or jurisdictions spiritual as be yet accustomed and
+used here in the Church of England, which necessarily and conveniently
+are requisite to be put in ure and execution for the
+time, not being repugnant, contrarient, or derogatory to the laws
+or statutes of the realm, nor to the prerogatives of the royal
+crown of the same, or any of them, shall be occupied, exercised,
+and put in ure for the time with this realm&rdquo; (35 Henry VIII.
+c. 16, 25 c. 19, 27 c. 8).</p>
+
+<p>The work was actually undertaken and finished in the reign
+of Edward VI. by a sub-committee of eight persons, under the
+name of the <i>Reformatio legum ecclesiasticarum</i>, which, however,
+never obtained the royal assent. Although the powers of the
+25 Henry VIII. c. 1 were revived by the 1 Elizabeth c. 1, the
+scheme was never executed, and the ecclesiastical laws remained
+on the footing assigned to them in that statute&mdash;so much of the
+old ecclesiastical laws might be used as had been actually in use,
+and was not repugnant to the laws of the realm.</p>
+
+<p>The statement is, indeed, made by Sir R. Phillimore (<i>Ecclesiastical
+Law</i>, 2nd ed., 1895) that the &ldquo;Church of England has at
+all times, before and since the Reformation, claimed the right
+of an independent Church in an independent kingdom, to be
+governed by the laws which she has deemed it expedient to
+adopt.&rdquo; This position can only be accepted if it is confined, as the
+authorities cited for it are confined, to the resistance of interference
+from abroad. If it mean that the Church, as distinguished
+from the kingdom, has claimed to be governed by laws of her
+own making, all that can be said is that the claim has been
+singularly unsuccessful. From the time of the Reformation no
+change has been made in the law of the Church which has not
+been made by the king and parliament, sometimes indirectly, as
+by confirming the resolutions of convocation, but for the most
+part by statute. The list of statutes cited in Sir R. Phillimore&rsquo;s
+<i>Ecclesiastical Law</i> fills eleven pages. It is only by a kind of legal
+fiction akin to the &ldquo;collegial&rdquo; theory mentioned above, that the
+Church can be said to have deemed it expedient to adopt these
+laws.</p>
+
+<p>The terms on which the Church Establishment of Ireland
+was abolished, by the Irish Council Act of 1869, may be mentioned.
+By sect. 20 the present ecclesiastical law was made binding on
+the members for the time being of the Church, &ldquo;as if they had
+mutually contracted and agreed to abide by and observe the
+same&rdquo;; and by section 21 it was enacted that the ecclesiastical
+courts should cease after the 1st of January 1871, and that the
+ecclesiastical laws of Ireland, except so far as relates to matrimonial
+causes and matters, should cease to exist as law. (See also
+<span class="sc"><a href="#artlinks">England, Church of</a></span>; <span class="sc"><a href="#artlinks">Establishment</a></span>; &amp;c.)</p>
+
+<div class="condensed">
+<p><span class="sc">Authorities.</span>&mdash;The number of works on ecclesiastical law is very
+great, and it must suffice here to mention a few of the more conspicuous
+modern ones: Ferdinand Walter, <i>Lehrbuch des Kirchenrechts
+aller christlichen Konfessionen</i> (14th ed., Bonn, 1871); G. Phillips,
+<i>Kirchenrecht</i>, Bde. i.-vii. (Regensburg, 1845-1872) incomplete; the
+text-book by Cardinal Hergenröther (<i>q.v.</i>); P. Hinschius, <i>Kirchenrecht
+der Katholiken und Protestanten in Deutschland</i>, 6 Bde. (Berlin,
+1869 sqq.), only the Catholic part, a masterly and detailed survey
+of the ecclesiastical law, finished; Sir Robert Phillimore, <i>Eccl. Law
+of the Church of England</i> (2nd ed., edited by Sir Walter Phillimore,
+2 vols., London, 1895). For further references see <span class="sc"><a href="#artlinks">Canon Law</a></span>, and
+the article &ldquo;Kirchenrecht&rdquo; in Herzog-Hauck, <i>Realencyklopädie</i>
+(ed. Leipzig, 1901).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECCLESIASTICUS<a name="ar120" id="ar120"></a></span> (abbreviated to <i>Ecclus.</i>), the alternative
+title given in the English Bible to the apocryphal book otherwise
+called &ldquo;The Wisdom of Jesus the son of Sirach.&rdquo; The Latin
+word <i>ecclesiasticus</i> is, properly speaking, not a name, but an
+epithet meaning &ldquo;churchly,&rdquo; so that it would serve as a designation
+of any book which was read in church or received ecclesiastical
+sanction, but in practice Ecclesiasticus has become a
+by-name for the Wisdom of Sirach. The true name of the book
+appears in the authorities in a variety of forms, the variation
+affecting both the author&rsquo;s name and the description of his book.
+The writer&rsquo;s full name is given in l. 27 (Heb. text) as &ldquo;Simeon the
+son of Jeshua (<i>i.e.</i> Jesus) the son of Eleazar the son of Sira.&rdquo;
+In the Greek text this name appears as &ldquo;Jesus son of Sirach
+Eleazar&rdquo; (probably a corruption of the Hebrew reading), and the
+epithet &ldquo;of Jerusalem&rdquo; is added, the translator himself being
+resident in Egypt. The whole name is shortened sometimes to
+&ldquo;Son of Sira,&rdquo; <i>Ben Sira</i> in Hebrew, <i>Bar Sira</i> in Aramaic, and
+sometimes (as in the title prefixed in the Greek cod. B) to <i>Sirach</i>.
+The work is variously described as the <i>Words</i> (Heb. text), the
+<i>Book</i> (Talmud), the <i>Proverbs</i> (Jerome), or the <i>Wisdom</i> of the son
+of Sira (or Sirach).</p>
+
+<p>Of the date of the book we have only one certain indication.
+It was translated by a person who says that he &ldquo;came into Egypt
+in the 38th year of Euergetes the king&rdquo; (Ptolemy VII.), <i>i.e.</i> in
+132 <span class="scs">B.C.</span>, and that he executed the work some time later. The
+translator believed that the writer of the original was his own
+grandfather (or ancestor, <span class="grk" title="pappos">&#960;&#940;&#960;&#960;&#959;&#962;</span>). It is therefore reasonable to
+suppose that the book was composed not later than the first half
+of the 2nd century <span class="scs">B.C.</span>, or (if we give the looser meaning to <span class="grk" title="pappos">&#960;&#940;&#960;&#960;&#959;&#962;</span>)
+even before the beginning of the century. Arguments for a pre-Maccabean
+date may be derived (<i>a</i>) from the fact that the book
+contains apparently no reference to the Maccabean struggles,
+(<i>b</i>) from the eulogy of the priestly house of Zadok which fell into
+disrepute during these wars for independence.</p>
+
+<p>In the Jewish Church Ecclesiasticus hovered on the border of
+the canon; in the Christian Church it crossed and recrossed the
+border. The book contains much which attracted and also
+much which repelled Jewish feeling, and it appears that it was
+necessary to pronounce against its canonicity. In the Talmud
+(Sanhedrin 100 b) Rabbi Joseph says that it is forbidden to read
+(<i>i.e.</i> in the synagogue) the book of ben Sira, and further that
+&ldquo;if our masters had not hidden the book (<i>i.e.</i> declared it uncanonical),
+we might interpret the good things which are in it&rdquo;
+(Schechter, <i>J. Q. Review</i>, iii. 691-692). In the Christian Church it
+was largely used by Clement of Alexandria (<i>c.</i> <span class="scs">A.D.</span> 200) and by
+St Augustine. The lists of the Hebrew canon, however, given by
+Melito (<i>c.</i> <span class="scs">A.D.</span> 180) and by Origen (<i>c.</i> <span class="scs">A.D.</span> 230) rightly exclude
+Ecclesiasticus, and Jerome (<i>c.</i> <span class="scs">A.D.</span> 390-400) writes: &ldquo;Let the Church
+read these two volumes (Wisdom of Solomon and Ecclesiasticus)
+for the instruction of the people, not for establishing the authority
+of the dogmas of the Church&rdquo; (<i>Praefatio in libros Salomonis</i>).
+In the chief MS. of the Septuagint, cod. B, Ecclesiasticus comes
+between Wisdom and Esther, no distinction being drawn between
+canonical and uncanonical. In the Vulgate it immediately
+precedes Isaiah. The council of Trent declared this book and
+the rest of the books reckoned in the Thirty-nine Articles as
+apocryphal to be canonical.</p>
+
+<p>The text of the book raises intricate problems which are still
+far from solution. The original Hebrew (rediscovered in fragments
+and published between 1896 and 1900) has come down
+to us in a mutilated and corrupt form. The beginning as far as
+iii. 7 is lost. There is a gap from xvi. 26 to xxx. 11. There are
+marginal readings which show that two different recensions
+existed once in Hebrew. The Greek version exists in two forms&mdash;(<i>a</i>)
+that preserved in cod. B and in the other uncial MSS., (<i>b</i>)
+that preserved in the cursive codex 248 (Holmes and Parsons).
+The former has a somewhat briefer text, the latter agrees more
+closely with the Hebrew text. The majority of Greek cursives
+agree generally with the Latin Vulgate, and offer the fuller text
+in a corrupt form. The Syriac (Peshitta) version is paraphrastic,
+but on the whole it follows the Hebrew text. Owing to the
+mutilation of the Hebrew by the accidents of time the Greek
+version retains its place as the chief authority for the text, and
+references by chapter and verse are usually made to it.</p>
+
+<p>Bickell and D.S. Margoliouth have supposed that the Hebrew
+text preserved in the fragments is not original, but a retranslation
+from the Greek or the Syriac or both. This view has not commended
+itself to the majority of scholars, but there is at least a
+residuum of truth in it. The Hebrew text, as we have it, has a
+history of progressive corruption behind it, and its readings
+can often be emended from the Septuagint, <i>e.g.</i> xxxvii. 11 (read
+<span title="umira al">&#1493;&#1502;&#1497;&#1512;&#1488; &#1506;&#1500;</span> for the meaningless <span title="umerer el">&#1493;&#1502;&#1512;&#1512; &#1488;&#1500;</span>). The Hebrew marginal
+readings occasionally seem to be translations from the Greek
+or Syriac, <i>e.g.</i> xxxviii. 4 (<span title="bara shamaym">&#1489;&#1512;&#1488; &#1513;&#1502;&#1497;&#1501;</span> for <span class="grk" title="ektisen pharmaka">&#7954;&#954;&#964;&#953;&#963;&#949;&#957; &#966;&#940;&#961;&#956;&#945;&#954;&#945;</span>). More
+frequently, however, strange readings of the Greek and Syriac
+<span class="pagenum"><a name="page869" id="page869"></a>869</span>
+are to be explained as corruptions of our present Hebrew.
+Substantially our Hebrew must be pronounced original.</p>
+
+<p>The restoration of a satisfactory text is beyond our hopes.
+Even before the Christian era the book existed in two recensions,
+for we cannot doubt, after reading the Greek translator&rsquo;s preface,
+that the translator amplified and paraphrased the text before
+him. It is probable that at least one considerable omission must
+be laid to his charge, for the hymn preserved in the Hebrew
+text after ch. li. 12 is almost certainly original. Ancient translators
+allowed themselves much liberty in their work, and Ecclesiasticus
+possessed no reputation for canonicity in the 2nd century <span class="scs">B.C.</span>
+to serve as a protection for its text. Much, however, may be
+done towards improving two of the recensions which now lie
+before us. The incomplete Hebrew text exists in four different
+MSS., and the study of the peculiarities of these had already
+proved fruitful. The Syriac text, made without doubt from the
+Hebrew, though often paraphrastic is often suggestive. The
+Greek translation, made within a century or half-century of the
+writing of the book, must possess great value for the criticism
+of the Hebrew text. The work of restoring true Hebrew readings
+may proceed with more confidence now that we have considerable
+portions of the Hebrew text to serve as a model. For the
+restoration of the Greek text we have, besides many Greek MSS.,
+uncial and cursive, the old Latin, the Syro-Hexaplar, the
+Armenian, Sahidic and Ethiopic versions, as well as a considerable
+number of quotations in the Greek and Latin Fathers. Each
+of the two recensions of the Greek must, however, be separately
+studied, before any restoration of the original Greek text can be
+attempted.</p>
+
+<p>The uncertainty of the text has affected both English versions
+unfavourably. The Authorized Version, following the corrupt
+cursives, is often wrong. The Revised Version, on the other
+hand, in following the uncial MSS. sometimes departs from the
+Hebrew, while the Authorized Version with the cursives agrees
+with it. Thus the Revised Version (with codd. <span title="alef">&#1488;</span>*, A, B, C) omits
+the whole of iii. 19, which the Authorized Version retains, but for
+the clause, &ldquo;Mysteries are revealed unto the meek,&rdquo; the Authorized
+Version has the support of the Hebrew, Syriac and cod. 248.
+Sometimes both versions go astray in places in which the Hebrew
+text recommends itself as original by its vigour; <i>e.g.</i> in vii. 26,
+where the Hebrew is,</p>
+
+<table class="reg f90" summary="poem"><tr><td> <div class="poemr">
+<p>Hast thou a wife? abominate her not.</p>
+<p>Hast thou a hated wife? trust not in her.</p>
+</div> </td></tr></table>
+
+<p class="noind">Again in ch. xxxviii. the Hebrew text in at least two interesting
+passages shows its superiority over the text which underlies both
+English versions.</p>
+
+<table class="pic f90" summary="Contents">
+
+<tr><td class="tcc" colspan="2"><i>Hebrew.</i></td>  <td class="tcc"><i>Revised Version</i> (<i>similarly<br />Authorized Version</i>).</td></tr>
+
+<tr><td class="tcl">ver. 1.</td>
+
+<td class="tcl" style="width: 40%; vertical-align: top;">Acquaint thyself with a
+physician before thou have
+need of him.</td>
+
+<td class="tcl" style="width: 40%; vertical-align: top;">Honour a physician according
+to thy need of him with the
+honours due unto him.</td></tr>
+
+<tr><td class="tcl">ver. 15.</td>
+
+<td class="tcl" style="width: 40%; vertical-align: top;">He that sinneth against his
+Maker will behave himself
+proudly against a physician.</td>
+
+<td class="tcl" style="width: 40%; vertical-align: top;">He that sinneth before his
+Maker, let him fall into the
+hands of the physician.</td></tr>
+</table>
+
+<p class="noind">In the second instance, while the Hebrew says that the man who
+rebels against his Heavenly Benefactor will <i>a fortiori</i> rebel
+against a human benefactor, the Greek text gives a cynical
+turn to the verse, &ldquo;Let the man who rebels against his true
+benefactor be punished through the tender mercies of a quack.&rdquo;
+The Hebrew text is probably superior also in xliv. 1, the opening
+words of the eulogy of the Fathers: &ldquo;Let me now praise favoured
+men,&rdquo; <i>i.e.</i> men in whom God&rsquo;s grace was shown. The Hebrew
+phrase is &ldquo;men of grace,&rdquo; as in v. 10. The Greek text of <i>v.</i> 1,
+&ldquo;famous men,&rdquo; seems to be nothing but a loose paraphrase,
+suggested by <i>v.</i> 2, &ldquo;The Lord manifested in them great
+glory.&rdquo;</p>
+
+<p>In character and contents Ecclesiasticus resembles the book of
+Proverbs. It consists mainly of maxims which may be described
+in turn as moral, utilitarian and secular. Occasionally the
+author attacks prevalent religious opinions, <i>e.g.</i> the denial of
+free-will (xv. 11-20), or the assertion of God&rsquo;s indifference towards
+men&rsquo;s actions (xxxv. 12-19). Occasionally, again, Ben Sira
+touches the highest themes, and speaks of the nature of God:
+&ldquo;He is All&rdquo; (xliii. 27); &ldquo;He is One from everlasting&rdquo; (xlii. 21,
+Heb. text); &ldquo;The mercy of the Lord is upon all flesh&rdquo; (xviii. 13).
+Though the book is imitative and secondary in character it
+contains several passages of force and beauty, <i>e.g.</i> ch. ii. (how to
+fear the Lord); xv. 11-20 (on free-will); xxiv. 1-22 (the song of
+wisdom); xlii. 15-25 (praise of the works of the Lord); xliv.
+1-15 (the well-known praise of famous men). Many detached
+sayings scattered throughout the book show a depth of insight,
+or a practical shrewdness, or again a power of concise speech,
+which stamps them on the memory. A few examples out of
+many may be cited. &ldquo;Call no man blessed before his death&rdquo;
+(xi. 28); &ldquo;He that toucheth pitch shall be defiled&rdquo; (xiii. 1);
+&ldquo;He hath not given any man licence to sin&rdquo; (xv. 20); &ldquo;Man
+cherisheth anger against man; and doth he seek healing from
+the Lord?&rdquo; (xxviii. 3); &ldquo;Mercy is seasonable ... as clouds of
+rain&rdquo; (xxxv. 20); &ldquo;All things are double one against another:
+and he hath made nothing imperfect&rdquo; (xlii. 24, the motto of
+Butler&rsquo;s <i>Analogy</i>); &ldquo;Work your work before the time cometh,
+and in his time he will give you your reward&rdquo; (li. 30). In spite,
+however, of the words just quoted it cannot be said that Ben
+Sira preaches a hopeful religion. Though he prays, &ldquo;Renew
+thy signs, and repeat thy wonders ... Fill Sion with thy
+majesty and thy Temple with thy glory&rdquo; (xxxvi. 6, 14 [19],
+Heb. text), he does not look for a Messiah. Of the resurrection
+of the dead or of the immortality of the soul there is no word,
+not even in xli. 1-4, where the author exhorts men not to fear
+death. Like the Psalmist (Ps. lxxxviii. 10, 11) he asks, &ldquo;Who
+shall give praise to the Most High in the grave?&rdquo; In his
+maxims of life he shows a somewhat frigid and narrow mind.
+He is a pessimist as regards women; &ldquo;From a woman was the
+beginning of sin; and because of her we all die&rdquo; (xxv. 24). He
+does not believe in home-spun wisdom; &ldquo;How shall he become
+wise that holdeth the plough?&rdquo; (xxxviii. 25). Artificers are not
+expected to pray like the wise man; &ldquo;In the handywork of
+their craft is their prayer&rdquo; (<i>v.</i> 34). Merchants are expected
+to cheat; &ldquo;Sin will thrust itself in between buying and selling&rdquo;
+(xxvii. 2).</p>
+
+<div class="condensed">
+<p><span class="sc">Bibliography.</span>&mdash;The literature of Ecclesiaticus has grown very
+considerably since the discovery of the first Hebrew fragment in
+1896. A useful summary of it is found at the end of Israel Levi&rsquo;s
+article, &ldquo;Sirach,&rdquo; in the <i>Jewish Encyclopedia</i>. Eberhard Nestle&rsquo;s
+article in Hastings&rsquo;s <i>Dictionary of the Bible</i> is important for its
+bibliographical information as well as in other respects. A complete
+edition of the Hebrew fragments in collotype facsimile was published
+jointly by the Oxford and Cambridge Presses in 1901.
+J.H.A. Hart&rsquo;s edition of cod. 248 throws much light on some of
+the problems of this book. It contains a fresh collation of all the chief
+authorities (Heb., Syr., Syr.-Hex., Lat. and Gr.) for the text, together
+with a complete textual commentary.</p>
+
+<p>The account given in the <i>Synopsis</i> attributed to Athanasius
+(Migne, <i>P.G.</i>, iv. 375-384) has an interest of its own. The beginning
+is given in the Authorized Version as &ldquo;A prologue made by an
+uncertain author.&rdquo;</p>
+</div>
+<div class="author">(W. E. B.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECGBERT,<a name="ar121" id="ar121"></a></span> or <span class="sc">Ecgberht</span> (d. 839), king of the West Saxons,
+succeeded to the throne in 802 on the death of Beorhtric. It
+is said that at an earlier period in his life he had been driven out
+for three years by Offa and Beorhtric. The accession of Ecgbert
+seems to have brought about an invasion by Æthelmund, earl
+of the Hwicce, who was defeated by Weoxtan, earl of Wiltshire.
+In 815 Ecgbert ravaged the whole of the territories of the West
+Welsh, which probably at this time did not include much more
+than Cornwall. The next important occurrence in the reign
+was the defeat of Beornwulf of Mercia at a place called Ellandun
+in 825. After this victory Kent, Surrey, Sussex and Essex submitted
+to Wessex; while the East Anglians, who slew Beornwulf
+shortly afterwards, acknowledged Ecgbert as overlord. In
+829 the king conquered Mercia, and Northumbria accepted
+him as overlord. In 830 he led a successful expedition against
+the Welsh. In 836 he was defeated by the Danes, but in 838
+he won a battle against them and their allies the West Welsh
+at Hingston Down in Cornwall. Ecgbert died in 839, after a
+reign of thirty-seven years, and was succeeded by his son Æthelwulf.
+A somewhat difficult question has arisen as to the
+parentage of Ecgbert. Under the year 825 the Chronicle states
+<span class="pagenum"><a name="page870" id="page870"></a>870</span>
+that in his eastern conquests Ecgbert recovered what had been
+the rightful property of his kin. The father of Ecgbert was
+called Ealhmund, and we find an Ealhmund, king in Kent,
+mentioned in a charter dated 784, who is identified with Ecgbert&rsquo;s
+father in a late addition to the Chronicle under the date 784.
+It is possible, however, that the Chronicle in 825 refers to some
+claim through Ine of Wessex from whose brother Ingeld Ecgbert
+was descended.</p>
+
+<div class="condensed">
+<p>See <i>Anglo-Saxon Chronicle</i>, edited by Earle and Plummer (Oxford,
+1899); W. de G. Birch, <i>Cartularium Saxonicum</i> (London, 1885-1893).
+Also a paper by Sir H.H. Howorth in <i>Numismatic Chronicle</i>,
+third series, vol. xx. pp. 66-87 (reprinted separately, London, 1900),
+where attention is called to the peculiar dating of several of Ecgbert&rsquo;s
+charters, and the view is put forward that he remained abroad considerably
+later than the date given by the Chronicle for his accession.
+On the other hand a charter in Birch, <i>Cart. Sax.</i>, purporting to date
+from 799, contains the curious statement that peace was made
+between C&oelig;nwulf and Ecgbert in that year.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECGBERT,<a name="ar122" id="ar122"></a></span> or <span class="sc">Ecgberht</span> (d. 766), archbishop of York, was
+made bishop of that see in 734 by Ceolwulf, king of Northumbria,
+succeeding Wilfrid II. on the latter&rsquo;s resignation. The pall was
+sent him in 735 and he became the first northern archbishop
+after Paulinus. He was the brother of Eadberht, who ruled
+Northumbria 737-758. He was the recipient of the famous
+letter of Bede, dealing with the evils arising from spurious
+monasteries. Ecgberht himself wrote a <i>Dialogus Ecclesiasticae
+Institutionis</i>, a <i>Penitentiale</i> and a <i>Pontificale</i>. He was a correspondent
+of St Boniface, who asks him to support his censure
+of Æthelbald of Mercia.</p>
+
+<div class="condensed">
+<p>See Bede, <i>Continuatio</i>, sub. ann. 732, 735, 766, and <i>Epistola ad
+Ecgberctum</i> (Plummer, Oxford, 1896); <i>Chronicle</i>, sub ann. 734, 735,
+738, 766 (Earle and Plummer, Oxford, 1899); Haddan and Stubbs,
+<i>Councils and Ecclesiastical Documents</i> (Oxford, 1869-1878), iii.
+403-431; <i>Proceedings of Surtees Society</i> (Durham, 1853).</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECGFRITH<a name="ar123" id="ar123"></a></span> (d. 685), king of Northumbria, succeeded his
+father Oswio in 671. He was married to Æthelthryth, daughter
+of Anna of East Anglia, who, however, took the veil shortly after
+Ecgfrith&rsquo;s accession, a step which possibly led to his long quarrel
+with Wilfrid archbishop of York. Ecgfrith married a second wife,
+Eormenburg, before 678, the year in which he expelled Wilfrid
+from his kingdom. Early in his reign he defeated the Picts who
+had risen in revolt. Between 671 and 675 Ecgfrith defeated
+Wulfhere of Mercia and seized Lindsey. In 679, however, he
+was defeated by Æthelred of Mercia, who had married his sister
+Osthryth, on the river Trent. Ecgfrith&rsquo;s brother Ælfwine was
+killed in the battle, and the province of Lindsey was given up
+when peace was restored at the intervention of Theodore of
+Canterbury. In 684 Ecgfrith sent an expedition to Ireland
+under his general Berht, which seems to have been unsuccessful.
+In 685, against the advice of Cuthbert, he led a force against
+the Picts under his cousin Burde, son of Bile, was lured by
+a feigned flight into their mountain fastnesses, and slain at
+Nechtanesmere (now Dunnichen) in Forfarshire. Bede dates
+the beginning of the decline of Northumbria from his death.
+He was succeeded by his brother Aldfrith.</p>
+
+<div class="condensed">
+<p>See Eddius, <i>Vita Wilfridi</i> (Raine, <i>Historians of Church of York</i>,
+Rolls, Series, London, 1879-1894), 19, 20, 24, 34, 39, 44; Bede, <i>Hist.
+Eccl.</i> (Plummer, Oxford, 1896), iii. 24, iv. 5, 12, 13, 18, 19, 21, 26.</p>
+</div>
+
+
+<hr class="art" />
+<p><span class="bold">ECGONINE,<a name="ar124" id="ar124"></a></span> in chemistry, C<span class="su">9</span>H<span class="su">15</span>NO<span class="su">3</span>, a cycloheptane derivative
+with a nitrogen bridge. It is obtained by hydrolysing cocaine
+with acids or alkalis, and crystallizes with one molecule of water,
+the crystals melting at 198° to 199° C. It is laevo-rotatory, and on
+warming with alkalis gives iso-ecgonine, which is dextro-rotatory.
+It is a tertiary base, and has also the properties of an acid and
+an alcohol. When boiled with caustic baryta it gives methylamine.
+It is the carboxylic acid corresponding to tropine, for it
+yields the same products on oxidation, and by treatment with
+phosphorus pentachloride is converted into anhydroecgonine,
+C<span class="su">9</span>H<span class="su">13</span>NO<span class="su">2</span>, which, when heated to 280° C. with hydrochloric
+acid, splits out carbon dioxide and yields tropidine, C<span class="su">8</span>H<span class="su">13</span>N.
+Anhydroecgonine melts at 235° C., and has an acid and a basic
+character. It is an unsaturated compound, and on oxidation
+with potassium permanganate gives succinic acid. It is apparently
+a tropidine monocarboxylic acid, for on exhaustive
+methylation it yields cycloheptatriene-1·3·5-carboxylic acid-7.
+Sodium in amyl alcohol solution reduces it to hydroecgonidine
+C<span class="su">9</span>H<span class="su">15</span>NO<span class="su">2</span>, while moderate oxidation by potassium permanganate
+converts it into <i>norecgonine</i>. The presence of the heptamethylene
+ring in these compounds is shown by the production
+of suberone by the exhaustive methylation, &amp;c., of hydroecgonidine
+ethyl ester (see <span class="sc"><a href="#artlinks">Polymethylenes</a></span> and <span class="sc"><a href="#artlinks">Tropine</a></span>). The
+above compounds may be represented as:</p>
+
+<div class="center pt2"><img style="width:502px; height:93px" src="images/img870.jpg" alt="" /></div>
+
+
+<hr class="art" />
+<p><span class="bold">ECHEGARAY Y EIZAGUIRRE, JOSÉ<a name="ar125" id="ar125"></a></span> (1833-&emsp;&emsp;), Spanish
+mathematician, statesman and dramatist, was born at Madrid
+in March 1833, and was educated at the grammar school of
+Murcia, whence he proceeded to the Escuela de Caminos at the
+capital. His exemplary diligence and unusual mathematical
+capacity were soon noticed. In 1853 he passed out at the head
+of the list of engineers, and, after a brief practical experience at
+Almería and Granada, was appointed professor of pure and
+applied mathematics in the school where he had lately been a
+pupil. His <i>Problemas de geometría analítica</i> (1865) and <i>Teorías
+modernas de la física unidad de las fuerzas materiales</i> (1867) are
+said to be esteemed by competent judges. He became a member
+of the Society of Political Economy, helped to found <i>La Revista</i>,
+and took a prominent part in propagating Free Trade doctrines
+in the press and on the platform. He was clearly marked out
+for office, and when the popular movement of 1868 overthrew the
+monarchy, he resigned his post for a place in the revolutionary
+cabinet. Between 1867 and 1874 he acted as minister of education
+and of finance; upon the restoration of the Bourbon
+dynasty he withdrew from politics, and won a new reputation as
+a dramatist.</p>
+
+<p>As early as 1867 he wrote <i>La Hija natural</i>, which was rejected,
+and remained unknown till 1877, when it appeared with the title
+of <i>Para tal culpa tal pena</i>. Another play, <i>La Última Noche</i>, also
+written in 1867, was produced in 1875; but in the latter year
+Echegaray was already accepted as the successful author of <i>El
+Libro talonario</i>, played at the Teatro de Apolo on the 18th of
+February 1874, under the transparent pseudonym of Jorge
+Hayaseca. Later in the same year Echegaray won a popular
+triumph with <i>La Esposa del vengador</i>, in which the good and bad
+qualities&mdash;the clever stagecraft and unbridled extravagance&mdash;of
+his later work are clearly noticeable. From 1874 onwards
+he wrote, with varying success, a prodigious number of plays.
+Among the most favourable specimens of his talent may be
+mentioned <i>En el puño de la espada</i> (1875); <i>O locura ó santidad</i>
+(1877), which has been translated into Swedish and Italian;
+<i>En el seno de la muerte</i> (1879), of which there exists an admirable
+German version by Fastenrath. <i>El gran Galeoto</i> (1881), perhaps
+the best of Echegaray&rsquo;s plays in conception and execution, has
+been translated into several languages, and still holds the stage.
+The humorous proverb, <i>¿Piensa mal y acertarás?</i> exemplifies the
+author&rsquo;s limitations, but the attempt is interesting as an instance
+of ambitious versatility. His susceptibility to new ideas is
+illustrated in such pieces as <i>Mariana</i> (1892), <i>Mancha que limpia</i>
+(1895), <i>El Hijo de Don Juan</i> (1892), and <i>El Loco Dios</i> (1900):
+these indicate a close study of Ibsen, and <i>El Loco Dios</i> more
+especially might be taken for an unintentional parody of
+Ibsen&rsquo;s symbolism.</p>
+
+<p>Echegaray succeeded to the literary inheritance of López de
+Ayala and of Tamayo y Baus; and though he possesses neither
+the poetic imagination of the first nor the instinctive tact of the
+second, it is impossible to deny that he has reached a larger
+audience than either. Not merely in Spain, but in every land
+where Spanish is spoken, and in cities as remote from Madrid as
+Munich and Stockholm, he has met with an appreciation incomparably
+beyond that accorded to any other Spanish dramatist
+of recent years. But it would be more than usually rash to
+prophesy that this exceptional popularity will endure. There
+have been signs of a reaction in Spain itself, and Echegaray&rsquo;s
+return to politics in 1905 was significant enough. He applies
+<span class="pagenum"><a name="page871" id="page871"></a>871</span>
+his mathematics to the drama; no writer excels him in artful
+construction, in the arrangement of dramatic scenes, in mere
+theatrical technique, in the focusing of attention on his chief
+personages. These are valuable gifts in their way, and Echegaray
+has, moreover, a powerful, gloomy imagination, which is momentarily
+impressive. In the drawing of character, in the invention
+of felicitous phrase, in the contrivance of verbal music, he is
+deficient. He alternates between the use of verse and prose;
+and his hesitancy in choosing a medium of expression is amply
+justified, for the writer&rsquo;s prose is not more distinguished than his
+verse. These serious shortcomings may explain the diminution
+of his vogue in Spain; they will certainly tell against him in the
+estimate of posterity.</p>
+<div class="author">(J. F.-K.)</div>
+
+
+<hr class="art" />
+<p><span class="bold">ÉCHELON<a name="ar126" id="ar126"></a></span> (Fr. from <i>échelle</i>, ladder), in military tactics, a
+formation of troops in which each body of troops is retired on,
+but not behind, the flank of the next in front, the position of
+the whole thus resembling the steps of a staircase. To form
+échelon from line, the parts of the line move off, each direct to
+its front, in succession, so that when the formation is completed
+the rightmost body, for example, is farthest advanced, the one
+originally next on its left is to the left rear, a third is to the left
+rear of the second, and so on. The word is also used more loosely
+to express successive lines, irrespective of distances and relative
+positions, <i>e.g.</i> the &ldquo;second échelon of ammunition supply,&rdquo;
+which is fully a day&rsquo;s march behind the first.</p>
+
+
+<hr class="art" />
+<p><span class="bold">ECHIDNA,<a name="ar127" id="ar127"></a></span> or <span class="sc">Porcupine Ant-Eater</span> (<i>Echidna aculeata</i>),
+one of the few species of Monotremata, the lowest subclass of
+Mammalia, forming the family Echidnidae. It is a native of
+Australia, where it chiefly abounds in New South Wales, inhabiting
+rocky and mountainous districts, where it burrows among the
+loose sand, or hides itself in crevices of rocks. In size and
+appearance it bears a considerable resemblance to the hedgehog,
+its upper surface being covered over with strong spines directed
+backwards, and on the back inwards, so as to cross each other
+on the middle line. The spines in the neighbourhood of the tail
+form a tuft sufficient to hide that almost rudimentary organ.
+The head is produced into a long tubular snout, covered with
+skin for the greater part of its length. The opening of the mouth
+is small, and from it the echidna puts forth its long slender
+tongue, lubricated with a viscous secretion, by means of which it
+seizes the ants and other insects on which it feeds. It has no
+teeth. Its legs are short and strong, and form, with its broad
+feet and large solid nails, powerful burrowing organs. In
+common with the other monotremes, the male echidna has its
+heel provided with a sharp hollow spur, connected with a secreting
+gland, and with muscles capable of pressing the secretion from
+the gland into the spur. It is a nocturnal or crepuscular animal,
+generally sleeping during the day, but showing considerable
+activity by night. When attacked it seeks to escape either by
+rolling itself into a ball, its erect spines proving a formidable
+barrier to its capture, or by burrowing into the sand, which its
+powerful limbs enable it to do with great celerity. &ldquo;The only
+mode of carrying the creature,&rdquo; writes G. Bennett (<i>Gatherings
+of a Naturalist in Australasia</i>), &ldquo;is by one of the hind legs; its
+powerful resistance and the sharpness of the spines will soon
+oblige the captor, attempting to seize it by any other part of the
+body, to relinquish his hold.&rdquo; In a younger stage of their
+development, however, the young are carried in a temporary
+abdominal pouch, to which they are transferred after hatching,
+and into which open the mammary glands. The echidnas are
+exceedingly restless in confinement, and constantly endeavour by
+burrowing to effect their escape. From the quantity of sand and
+mud always found in the alimentary canal of these animals,
+it is supposed that these ingredients must be necessary to the
+proper digestion of their insect food.</p>
+
+<p>There are two varieties of this species, the Port Moresby
+echidna and the hairy echidna. The last-mentioned is found in
+south-eastern New Guinea, Australia and Tasmania. In all the
+spines are mixed with hair; in the Tasmanian race they are
+nearly hidden by the long harsh fur. Of the three-clawed
+echidnas (<i>Proechidna</i>) confined to New Guinea there are two
+species, Bruijn&rsquo;s echidna (<i>P. bruijnii</i>), discovered in 1877 in the
+mountains on the north-east coast at an elevation of 3500 ft., and
+the black-spined echidna (<i>P. nigroaculeata</i>) of larger size&mdash;the
+type specimen measuring 31 in., as against 24 in.&mdash;with shorter
+claws.</p>
+
+<hr class="art" />
+
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Encyclopaedia Britannica, 11th
+Edition, Volume 8, Slice 9, by Various
+
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+</body>
+</html>
+
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+The Project Gutenberg EBook of Encyclopaedia Britannica, 11th Edition,
+Volume 8, Slice 9, by Various
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 9
+       "Dyer" to "Echidna"
+
+Author: Various
+
+Release Date: January 8, 2011 [EBook #34878]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK ENCYCLOPAEDIA BRITANNICA ***
+
+
+
+
+Produced by Marius Masi, Don Kretz and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+
+
+
+Transcriber's notes:
+
+(1) Numbers following letters (without space) like C2 were originally
+      printed in subscript. Letter subscripts are preceded by an
+      underscore, like C_n.
+
+(2) Characters following a carat (^) were printed in superscript.
+
+(3) Side-notes were relocated to function as titles of their respective
+      paragraphs.
+
+(4) Macrons and breves above letters and dots below letters were not
+      inserted.
+
+(5) dP stands for the partial-derivative symbol, or curled 'd'.
+
+(6) [oo] stands for the infinity symbol, and [int] for the integral
+      symbol.
+
+(7) Letters followed with a grave accent "`" have originally dots above.
+
+(8) The following typographical errors have been corrected:
+
+    ARTICLE DYER, JOHN: "His poems were collected by Dodsley in 1770,
+      and by Mr Edward Thomas in 1903 for the Welsh Library, vol. iv."
+      'poems' amended from 'peoms'.
+
+    ARTICLE EAR: "The membranous semicircular canals are very much
+      smaller in section than the bony; in the ampulla of each is a
+      ridge..." 'the' amended from 'tbe'.
+
+    ARTICLE EARTH, FIGURE OF THE: "O. Callandreau, 'Memoire sur la
+      theorie de la figure des planetes,' Ann. obs. de Paris (1889);..."
+      'Callandreau' amended from 'Callendreau'.
+
+    ARTICLE EATON, THEOPHILUS: "In October 1639 a form of government
+      was adopted, based on the Mosaic Law, and Eaton was elected
+      governor..." 'Mosaic' amended from 'Mosiac'.
+
+    ARTICLE ECCLESIASTES: "A particular instance is mentioned (ix.
+      13-15) of a beleaguered city saved by a wise man; but the man
+      happened to be poor, and no one remembered him." 'beleaguered'
+      amended from 'beleagured'.
+
+    ARTICLE ECCLESIASTES: "Such assertions as those of ii. 26 (God
+      gives joy to him who pleases him, and makes the sinner toil to lay
+      up for the latter),..." 'and' amended from 'amd'.
+
+    ARTICLE ECCLESIASTES: "This disagreement comes largely from the
+      attempts made to find definitely expressed Greek philosophical
+      dogmas in the book; such formulas it has not, but the general air
+      of Greek reflection seems unmistakable. The scepticism of Koheleth
+      differs from that of Job in quality and scope..." 'the' originally
+      repeated twice.
+
+    ARTICLE ECCLESIASTICAL JURISDICTION: "In the first case, they may
+      be punished by the ordinary of the place, acting as delegate of the
+      pope without special appointment (Conc. Trid. Sess. vi. c. 3)."
+      'special' amended from 'speical'.
+
+
+
+
+          ENCYCLOPAEDIA BRITANNICA
+
+  A DICTIONARY OF ARTS, SCIENCES, LITERATURE
+           AND GENERAL INFORMATION
+
+              ELEVENTH EDITION
+
+
+           VOLUME VIII, SLICE IX
+
+              Dyer to Echidna
+
+
+
+
+ARTICLES IN THIS SLICE:
+
+
+  DYER, SIR EDWARD              EAST LIVERPOOL
+  DYER, JOHN                    EAST LONDON
+  DYER, THOMAS HENRY            EASTON
+  DYMOKE                        EAST ORANGE
+  DYNAMICS                      EASTPORT
+  DYNAMITE                      EAST PROVIDENCE
+  DYNAMO                        EAST PRUSSIA
+  DYNAMOMETER                   EASTWICK, EDWARD BACKHOUSE
+  DYNASTY                       EATON, DORMAN BRIDGMAN
+  DYSART                        EATON, MARGARET O'NEILL
+  DYSENTERY                     EATON, THEOPHILUS
+  DYSPEPSIA                     EATON, WILLIAM
+  DYSTELEOLOGY                  EATON, WYATT
+  DZUNGARIA                     EAU CLAIRE
+  E                             EAU DE COLOGNE
+  EA                            EAUX-BONNES
+  EABANI                        EAVES
+  EACHARD, JOHN                 EAVESDRIP
+  EADBALD                       EBBW VALE
+  EADIE, JOHN                   EBEL, HERMANN WILHELM
+  EADMER                        EBEL, JOHANN GOTTFRIED
+  EADS, JAMES BUCHANAN          EBER, PAUL
+  EAGLE                         EBERBACH (town of Germany)
+  EAGLEHAWK                     EBERBACH (monastery of Germany)
+  EAGRE                         EBERHARD
+  EAKINS, THOMAS                EBERHARD, CHRISTIAN AUGUST GOTTLOB
+  EALING                        EBERHARD, JOHANN AUGUSTUS
+  EAR                           EBERLIN, JOHANN ERNST
+  EARL                          EBERS, GEORG MORITZ
+  EARLE, JOHN                   EBERSWALDE
+  EARLE, RALPH                  EBERT, FRIEDRICH ADOLF
+  EARL MARSHAL                  EBINGEN
+  EARLOM, RICHARD               EBIONITES
+  EARLSTON                      EBNER-ESCHENBACH, MARIE
+  EARLY, JUBAL ANDERSON         EBOLI
+  EARLY ENGLISH PERIOD          EBONY
+  EARN                          EBRARD, JOHANNES HEINRICH AUGUST
+  EARNEST                       EBRO
+  EAR-RING                      EBROIN
+  EARTH                         EBURACUM
+  EARTH, FIGURE OF THE          ECA DE QUEIROZ, JOSE MARIA
+  EARTH CURRENTS                ECARTE
+  EARTH-NUT                     ECBATANA
+  EARTH PILLAR                  ECCARD, JOHANN
+  EARTHQUAKE                    ECCELINO DA ROMANO
+  EARTH-STAR                    ECCENTRIC
+  EARTHWORM                     ECCHELLENSIS, ABRAHAM
+  EARWIG                        ECCLES
+  EASEMENT                      ECCLESFIELD
+  EAST, ALFRED                  ECCLESHALL
+  EAST ANGLIA                   ECCLESIA
+  EASTBOURNE                    ECCLESIASTES
+  EAST CHICAGO                  ECCLESIASTICAL COMMISSIONERS
+  EASTER                        ECCLESIASTICAL JURISDICTION
+  EASTER ISLAND                 ECCLESIASTICAL LAW
+  EASTERN BENGAL AND ASSAM      ECCLESIASTICUS
+  EASTERN QUESTION, THE         ECGBERT (king of the West Saxons)
+  EAST GRINSTEAD                ECGBERT (archbishop of York)
+  EAST HAM                      ECGFRITH
+  EASTHAMPTON                   ECGONINE
+  EAST HAMPTON                  ECHEGARAY Y EIZAGUIRRE, JOSE
+  EAST INDIA COMPANY            ECHELON
+  EAST INDIES                   ECHIDNA
+  EASTLAKE, SIR CHARLES LOCK
+
+
+
+
+DYER, SIR EDWARD (d. 1607), English courtier and poet, son of Sir Thomas
+Dyer, Kt., was born at Sharpham Park, Somersetshire. He was educated,
+according to Anthony a Wood, either at Balliol College or at Broadgates
+Hall, Oxford. He left the university without taking a degree, and after
+some time spent abroad appeared at Queen Elizabeth's court. His first
+patron was the earl of Leicester, who seems to have thought of putting
+him forward as a rival to Sir Christopher Hatton in the queen's favour.
+He is mentioned by Gabriel Harvey with Sidney as one of the ornaments of
+the court. Sidney in his will desired that his books should be divided
+between Fulke Greville (Lord Brooke) and Dyer. He was employed by
+Elizabeth on a mission (1584) to the Low Countries, and in 1589 was sent
+to Denmark. In a commission to inquire into manors unjustly alienated
+from the crown in the west country he did not altogether please the
+queen, but he received a grant of some forfeited lands in Somerset in
+1588. He was knighted and made chancellor of the order of the Garter in
+1596. William Oldys says of him that he "would not stoop to fawn," and
+some of his verses seem to show that the exigencies of life at court
+oppressed him. He was buried at St Saviour's, Southwark, on the 11th of
+May 1607. Wood says that many esteemed him to be a Rosicrucian, and that
+he was a firm believer in alchemy. He had a great reputation as a poet
+among his contemporaries, but very little of his work has survived.
+Puttenham in the _Arte of English Poesie_ speaks of "Maister Edward
+Dyar, for Elegie most sweete, solempne, and of high conceit." One of the
+poems universally accepted as his is "My Mynde to me a kingdome is."
+Among the poems in _England's Helicon_ (1600), signed S.E.D., and
+included in Dr A.B. Grosart's collection of Dyer's works (_Miscellanies
+of the Fuller Worthies Library_, vol. iv., 1876) is the charming
+pastoral "My Phillis hath the morninge sunne," but this comes from the
+_Phillis_ of Thomas Lodge. Grosart also prints a prose tract entitled
+_The Prayse of Nothing_ (1585). The _Sixe Idillia_ from Theocritus,
+reckoned by J.P. Collier among Dyer's works, were dedicated to, not
+written by, him.
+
+
+
+
+DYER, JOHN (c. 1700-1758), British poet, the son of a solicitor, was
+born in 1699 or 1700 at Aberglasney, in Carmarthenshire. He was sent to
+Westminster school and was destined for the law, but on his father's
+death he began to study painting. He wandered about South Wales,
+sketching and occasionally painting portraits. In 1726 his first poem,
+_Grongar Hill_, appeared in a miscellany published by Richard Savage,
+the poet. It was an irregular ode in the so-called Pindaric style, but
+Dyer entirely rewrote it into a loose measure of four cadences, and
+printed it separately in 1727. It had an immediate and brilliant
+success. _Grongar Hill_, as it now stands, is a short poem of only 150
+lines, describing in language of much freshness and picturesque charm
+the view from a hill overlooking the poet's native vale of Towy. A visit
+to Italy bore fruit in _The Ruins of Rome_ (1740), a descriptive piece
+in about 600 lines of Miltonic blank verse. He was ordained priest in
+1741, and held successively the livings of Calthorp in Leicestershire,
+Belchford (1751), Coningsby (1752), and Kirby-on-Bane (1756), the last
+three being Lincolnshire parishes. He married, in 1741, a Miss Ensor,
+said to be descended from the brother of Shakespeare. In 1757 he
+published his longest work, the didactic blank-verse epic of _The
+Fleece_, in four books, discoursing of the tending of sheep, of the
+shearing and preparation of the wool, of weaving, and of trade in
+woollen manufactures. The town took no interest in it, and Dodsley
+facetiously prophesied that "Mr Dyer would be buried in woollen." He
+died at Coningsby of consumption, on the 15th of December 1758.
+
+  His poems were collected by Dodsley in 1770, and by Mr Edward Thomas
+  in 1903 for the _Welsh Library_, vol. iv.
+
+
+
+
+DYER, THOMAS HENRY (1804-1888), English historical and antiquarian
+writer, was born in London on the 4th of May 1804. He was originally
+intended for a business career, and for some time acted as clerk in a
+West India house; but finding his services no longer required after the
+passing of the Negro Emancipation Act, he decided to devote himself to
+literature. In 1850 he published the _Life of Calvin_, a conscientious
+and on the whole impartial work, though the character of Calvin is
+somewhat harshly drawn, and his influence in the religious world
+generally is insufficiently appreciated. Dyer's first historical work
+was the _History of Modern Europe_ (1861-1864; 3rd ed. revised and
+continued to the end of the 19th century, by A. Hassall, 1901), a
+meritorious compilation and storehouse of facts, but not very readable.
+The _History of the City of Rome_ (1865) down to the end of the middle
+ages was followed by the _History of the Kings of Rome_ (1868), which,
+upholding against the German school the general credibility of the
+account of early Roman history, given in Livy and other classical
+authors, was violently attacked by J.R. Seeley and the _Saturday
+Review_, as showing ignorance of the comparative method. More favourable
+opinions of the work were expressed by others, but it is generally
+agreed that the author's scholarship is defective and that his views are
+far too conservative. _Roma Regalis_ (1872) and _A Plea for Livy_ (1873)
+were written in reply to his critics. Dyer frequently visited Greece and
+Italy, and his topographical works are probably his best; amongst these
+mention may be made of _Pompeii, its History, Buildings and Antiquities_
+(1867, new ed. in Bohn's _Illustrated Library_), and _Ancient Athens,
+its History, Topography and Remains_ (1873). His last publication was
+_On Imitative Art_ (1882). He died at Bath on the 30th of January 1888.
+
+
+
+
+DYMOKE, the name of an English family holding the office of king's
+champion. The functions of the champion were to ride into Westminster
+Hall at the coronation banquet, and challenge all comers to impugn the
+king's title (see CHAMPION). The earliest record of the ceremony at the
+coronation of an English king dates from the accession of Richard II. On
+this occasion the champion was Sir John Dymoke (d. 1381), who held the
+manor of Scrivelsby, Lincolnshire, in right of his wife Margaret,
+granddaughter of Joan Ludlow, who was the daughter and co-heiress of
+Philip Marmion, last Baron Marmion. The Marmions claimed descent from
+the lords of Fontenay, hereditary champions of the dukes of Normandy,
+and held the castle of Tamworth, Leicestershire, and the manor of
+Scrivelsby, Lincolnshire. The right to the championship was disputed
+with the Dymoke family by Sir Baldwin de Freville, lord of Tamworth, who
+was descended from an elder daughter of Philip Marmion. The court of
+claims eventually decided in favour of the owners of Scrivelsby on the
+ground that Scrivelsby was held in grand serjeanty, that is, that its
+tenure was dependent on rendering a special service, in this case the
+championship.
+
+Sir Thomas Dymoke (1428?-1471) joined a Lancastrian rising in 1469, and,
+with his brother-in-law Richard, Lord Willoughby and Welles, was
+beheaded in 1471 by order of Edward IV. after he had been induced to
+leave sanctuary on a promise of personal safety. The estates were
+restored to his son Sir Robert Dymoke (d. 1546), champion at the
+coronations of Richard III., Henry VII. and Henry VIII., who
+distinguished himself at the siege of Tournai and became treasurer of
+the kingdom. His descendants acted as champions at successive
+coronations. Lewis Dymoke (d. 1820) put in an unsuccessful claim before
+the House of Lords for the barony of Marmion. His nephew Henry
+(1801-1865) was champion at the coronation of George IV. He was
+accompanied on that occasion by the duke of Wellington and Lord Howard
+of Effingham. Henry Dymoke was created a baronet; he was succeeded by
+his brother John, rector of Scrivelsby (1804-1873), whose son Henry
+Lionel died without issue in 1875, when the baronetcy became extinct,
+the estate passing to a collateral branch of the family. After the
+coronation of George IV. the ceremony was allowed to lapse, but at the
+coronation of King Edward VII. H.S. Dymoke bore the standard of England
+in Westminster Abbey.
+
+
+
+
+DYNAMICS (from Gr. [Greek: dynamis], strength), the name of a branch of
+the science of Mechanics (q.v.). The term was at one time restricted to
+the treatment of motion as affected by force, being thus opposed to
+Statics, which investigated equilibrium or conditions of rest. In more
+recent times the word has been applied comprehensively to the action of
+force on bodies either at rest or in motion, thus including "dynamics"
+(now termed kinetics) in the restricted sense and "statics."
+
+ANALYTICAL DYNAMICS.--The fundamental principles of dynamics, and their
+application to special problems, are explained in the articles MECHANICS
+and MOTION, LAWS OF, where brief indications are also given of the more
+general methods of investigating the properties of a dynamical system,
+independently of the accidents of its particular constitution, which
+were inaugurated by J.L. Lagrange. These methods, in addition to the
+unity and breadth which they have introduced into the treatment of pure
+dynamics, have a peculiar interest in relation to modern physical
+speculation, which finds itself confronted in various directions with
+the problem of explaining on dynamical principles the properties of
+systems whose ultimate mechanism can at present only be vaguely
+conjectured. In determining the properties of such systems the methods
+of analytical geometry and of the infinitesimal calculus (or, more
+generally, of mathematical analysis) are necessarily employed; for this
+reason the subject has been named Analytical Dynamics. The following
+article is devoted to an outline of such portions of general dynamical
+theory as seem to be most important from the physical point of view.
+
+
+  1. _General Equations of Impulsive Motion._
+
+  The systems contemplated by Lagrange are composed of discrete
+  particles, or of rigid bodies, in finite number, connected (it may be)
+  in various ways by invariable geometrical relations, the fundamental
+  postulate being that the position of every particle of the system at
+  any time can be completely specified by means of the instantaneous
+  values of a finite number of independent variables q1, q2, ... q_n,
+  each of which admits of continuous variation over a certain range, so
+  that if x, y, z be the Cartesian co-ordinates of any one particle, we
+  have for example
+
+    x = [f](q1, q2, ... q_n), y = &c., z = &c.,   (1)
+
+  where the functions [f] differ (of course) from particle to particle.
+  In modern language, the variables q1, q2, ... q_n are _generalized
+  co-ordinates_ serving to specify the _configuration_ of the system;
+  their derivatives with respect to the time are denoted by q`1, q`2,
+  ... q`_n, and are called the _generalized components of velocity_. The
+  continuous sequence of configurations assumed by the system in any
+  actual or imagined motion (subject to the given connexions) is called
+  the _path_.
+
+
+    Impulsive motion.
+
+  For the purposes of a connected outline of the whole subject it is
+  convenient to deviate somewhat from the historical order of
+  development, and to begin with the consideration of _impulsive_
+  motion. Whatever the actual motion of the system at any instant, we
+  may conceive it to be generated instantaneously from rest by the
+  application of proper impulses. On this view we have, if x, y, z be
+  the rectangular co-ordinates of any particle m,
+
+    mx` = X', my` = Y', mz` = Z',   (2)
+
+  where X', Y', Z' are the components of the impulse on m. Now let
+  [delta]x, [delta]y, [delta]z be any infinitesimal variations of x, y,
+  z which are consistent with the connexions of the system, and let us
+  form the equation
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+       [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z),   (3)
+
+  where the sign [Sigma] indicates (as throughout this article) a
+  summation extending over all the particles of the system. To transform
+  (3) into an equation involving the variations [delta]q1, [delta]q2,
+  ... of the generalized co-ordinates, we have
+
+          dPx        dPx
+    x` = ---- q`1 + ---- q`2 + ..., &c., &c.   (4)
+         dPq1       dPq2
+
+               dPx              dPx
+    [delta]x = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.   (5)
+               dPq1             dPq2
+
+  and therefore
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+        (A11q`1 + A12q`2 + ...)[delta]q1 +
+        (A21q`1 + A22q`2 + ...)[delta]q2 + ...,   (6)
+
+  where
+                     _                                 _
+                    |  / dPx \ squared    / dPy \ squared    / dPz \ squared |               \
+    A_rr = [Sigma]m | ( ----- ) + ( ----- ) + ( ----- ) |,               |
+                    |_ \dPq_r/     \dPq_r/     \dPq_r/ _|                |
+                     _                                        _           > (7)
+                    |  dPx   dPx     dPy   dPy     dPz   dPz   |         |
+    A_rs = [Sigma]m | ----- ----- + ----- ----- + ----- -----  | = A_sr. |
+                    |_dPq_r dPq_s   dPq_r dPq_s   dPq_r dPq_s _|        /
+
+  If we form the expression for the kinetic energy [Tau] of the system,
+  we find
+
+    2[Tau] = [Sigma]m(x` squared + y` squared + z` squared) = A11q`1 squared + A22q`2 squared + ...
+       + 2A12q`1q`2 + ... (8)
+
+  The coefficients A11, A22, ... A12, ... are by an obvious analogy
+  called the _coefficients of inertia_ of the system; they are in
+  general functions of the co-ordinates q1, q2, ... . The equation (6)
+  may now be written
+
+                                                     dP[Tau]             dP[Tau]
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = ------- [delta]q1 + ------- [delta]q2 + ... (9)
+                                                      dPq`1               dPq`2
+
+  This maybe regarded as the cardinal formula in Lagrange's method. For
+  the right-hand side of (3) we may write
+
+    [Sigma](X'[delta]x + Y'[delta]y + Z'[delta]z) = Q'1[delta]q1 + Q'2[delta]q2 + ... ,  (10)
+
+  where
+
+                   /   dPx       dPy       dPz \
+    Q'_r = [Sigma]( X'----- + Y'----- + Z'----- ).  (11)
+                   \  dPq_r     dPq_r     dPq_r/
+
+  The quantities Q1, Q2, ... are called the _generalized components of
+  impulse_. Comparing (9) and (10), we have, since the variations
+  [delta]q1, [delta]q2,... are independent,
+
+    dP[Tau]        dP[Tau]
+    ------- = Q'1, ------- = Q'2, ...  (12)
+     dPq`1          dPq`2
+
+  These are the general equations of impulsive motion. It is now usual
+  to write
+
+          dP[Tau]
+    p_r = -------   (13)
+          dPq`_r
+
+  The quantities p1, p2, ... represent the effects of the several
+  component impulses on the system, and are therefore called the
+  _generalized components of momentum_. In terms of them we have
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) = p1[delta]q1 + p2[delta]q2 + ...  (14)
+
+  Also, since [Tau] is a homogeneous quadratic function of the
+  velocities q`1, q`2 ...,
+
+    2[Tau] = p1q`1 + p2q`2 + ...  (15)
+
+  This follows independently from (14), assuming the special variations
+  [delta]x = x`dt, &c., and therefore [delta]q1 = q`1dt, [delta]q2 =
+  q`2dt, ...
+
+
+    Reciprocal theorems.
+
+  Again, if the values of the velocities and the momenta in any other
+  motion of the system through the same configuration be distinguished
+  by accents, we have the identity
+
+    p1q`'1 + p2q`'2 + ... = p'1q`1 + p'2q`2 + ...,   (16)
+
+  each side being equal to the symmetrical expression
+
+    A11q`1q''1 + A22q`2q`'2 + ... + A12(q`1q`'2 + q`'1q`2) + ...  (17)
+
+  The theorem (16) leads to some important reciprocal relations. Thus,
+  let us suppose that the momenta p1, p2, ... all vanish with the
+  exception of p1, and similarly that the momenta p'1, p'2, ... all
+  vanish except p'2. We have then p1q`'1 = p'2q`2, or
+
+    q`2 : p1 = q`'1 : p'2                       (18)
+
+  The interpretation is simplest when the co-ordinates q1, q2 are both
+  of the same kind, e.g. both lines or both angles. We may then
+  conveniently put p1 = p'2, and assert that the velocity of the first
+  type due to an impulse of the second type is equal to the velocity of
+  the second type due to an equal impulse of the first type. As an
+  example, suppose we have a chain of straight links hinged each to the
+  next, extended in a straight line, and free to move. A blow at right
+  angles to the chain, at any point P, will produce a certain velocity
+  at any other point Q; the theorem asserts that an equal velocity will
+  be produced at P by an equal blow at Q. Again, an impulsive couple
+  acting on any link A will produce a certain angular velocity in any
+  other link B; an equal couple applied to B will produce an equal
+  angular velocity in A. Also if an impulse F applied at P produce an
+  angular velocity [omega] in a link A, a couple Fa applied to A will
+  produce a linear velocity [omega]a at P. Historically, we may note
+  that reciprocal relations in dynamics were first recognized by H.L.F.
+  Helmholtz in the domain of acoustics; their use has been greatly
+  extended by Lord Rayleigh.
+
+
+    Velocities in terms of momenta.
+
+  The equations (13) determine the momenta p1, p2,... as linear
+  functions of the velocities q`1, q`2,... Solving these, we can
+  express q`1, q`2 ... as linear functions of p1, p2,... The
+  resulting equations give us the velocities produced by any given
+  system of impulses. Further, by substitution in (8), we can express
+  the kinetic energy as a homogeneous quadratic function of the momenta
+  p1, p2,... The kinetic energy, _as so expressed_, will be denoted by
+  [Tau]'; thus
+
+    2[Tau]' = A'11p1 squared + A'22p2 squared + ... + 2A'12p - p2 + ...   (19)
+
+  where A'11, A'22,... A'12,... are certain coefficients depending on
+  the configuration. They have been called by Maxwell the _coefficients
+  of mobility_ of the system. When the form (19) is given, the values
+  of the velocities in terms of the momenta can be expressed in a
+  remarkable form due to Sir W.R. Hamilton. The formula (15) may be
+  written
+
+    p1q`1 + p2q`2 + ... = [Tau] + [Tau]', ...   (20)
+
+  where [Tau] is supposed expressed as in (8), and [Tau]' as in (19).
+  Hence if, for the moment, we denote by [delta] a variation affecting
+  the velocities, and therefore the momenta, but not the configuration,
+  we have
+
+    p1[delta]q`1 + q`1[delta]p + p2[delta]q`2 + q`2[delta]p2 + ... = [delta][Tau] + [delta][Tau]'
+
+      dP[Tau]              dP[Tau]                    dP[Tau]'             dP[Tau]'
+    = ------- [delta]q`1 + ------- [delta]q`2 + ... + -------- [delta]p1 + -------- [delta]p2 + ...  (21)
+      dPq`1                dPq`2                       dPp1                 dPp2
+
+  In virtue of (13) this reduces to
+
+                                        dP[Tau]'            dP[Tau]'
+    q`1[delta]p1 + q`2[delta]p2 + ... = ------- [delta]p1 + ------- [delta]p2  + ...  (22)
+                                         dPp1                dPp2
+
+  Since [delta]p1, [delta]p2, ... may be taken to be independent, we
+  infer that
+
+          dP[Tau]'       dP[Tau]'
+    q`1 = -------, q`2 = -------, ...  (23)
+           dPp1           dPp2
+
+  In the very remarkable exposition of the matter given by James Clerk
+  Maxwell in his _Electricity and Magnetism_, the Hamiltonian
+  expressions (23) for the velocities in terms of the impulses are
+  obtained directly from first principles, and the formulae (13) are
+  then deduced by an inversion of the above argument.
+
+
+    Routh's modification.
+
+  An important modification of the above process was introduced by E.J.
+  Routh and Lord Kelvin and P.G. Tait. Instead of expressing the kinetic
+  energy in terms of the velocities alone, or in terms of the momenta
+  alone, we may express it in terms of the velocities corresponding to
+  some of the co-ordinates, say q1, q2, ... q_m, and of the momenta
+  corresponding to the remaining co-ordinates, which (for the sake of
+  distinction) we may denote by [chi], [chi]', [chi]", .... Thus, [Tau]
+  being expressed as a homogeneous quadratic function of q`1, q`2, ...
+  q`_m, [chi]`, [chi]`', [chi]`", ..., the momenta corresponding to the
+  co-ordinates [chi], [chi]', [chi]", ... may be written
+
+               dP[Tau]               dP[Tau]                dP[Tau]
+    [kappa]  = --------, [kappa]' = ---------, [kappa]" = ------------, ...  (24)
+               dP[chi]`             dP[chi]`'              dP[.[chi]`"
+
+  These equations, when written out in full, determine [chi]`, [chi]`',
+  [chi]`", ... as linear functions of q`1, q`2, ... q`_m, [kappa],
+  [kappa]', [kappa]",... We now consider the function
+
+    R = [Tau] - [kappa][chi]' - [kappa]'[chi]]`' - [kappa]"[chi]]`" - ...,  (25)
+
+  supposed expressed, by means of the above relations in terms of q`1,
+  q`2, ... q`_m, [kappa], [kappa]', [kappa]",... Performing the
+  operation [delta] on both sides of (25), we have
+
+     dPR                        dPR                           dP[Tau]                    dP[Tau]
+    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... + -------- [delta][chi]` + ...
+    dPq`1                    dP[kappa]                         dPq`1                     dP[chi]`
+
+       - [kappa]dP[chi]` - [chi]`[delta][kappa] - ... ,   (26)
+
+  where, for brevity, only one term of each type has been exhibited.
+  Omitting the terms which cancel in virtue of (24), we have
+
+     dPR                        dPR                           dP[Tau]
+    ----- [delta]q`1 + ... + --------- [delta][kappa] + ... = ------- [delta]q`1 + ... - [chi]`[delta][kappa] - ...  (27)
+    dPq`1                    dP[kappa]                        dPq`1
+
+  Since the variations [delta]q1, [delta]q2, ... [delta]q_m,
+  [delta][kappa], [delta][kappa]', [delta][kappa]", ... may be taken to
+  be independent, we have
+
+         dP[Tau]     dPR        dP[Tau]     dPR
+    p1 = -------  = -----, p2 = -------  = -----, ...  (28)
+          dPq`1     dPq`1        dPq`2     dPq`2
+
+  and
+
+                  dPR                    dPR                      dPR
+    [chi]` = - ---------, [chi]`' = - ----------, [chi]]`" = - ---------, ...  (29)
+               dP[kappa]              dP[kappa]'               dP[kappa]"
+
+  An important property of the present transformation is that, when
+  expressed in terms of the new variables, the kinetic energy is the sum
+  of two homogeneous quadratic functions, thus
+
+    [Tau] = [@] + K,  (30)
+
+  where [@] involves the velocities q`1, q`2, ... q`_m alone, and K the
+  momenta [kappa], [kappa]', [kappa]", ... alone. For in virtue of (29)
+  we have, from (25),
+
+                 /            dPR                  dPR                    dPR          \
+    [Tau] = R - ( [kappa]  --------- + [kappa]' ---------- + [kappa]" ----------- + ... ),  (31)
+                 \         dP[kappa]            dP[kappa]'             dP[kappa]"      /
+
+  and it is evident that the terms in R which are bilinear in respect of
+  the two sets of variables q`1, q`2, ... q`_m and [kappa], [kappa]',
+  [kappa]", ... will disappear from the right-hand side.
+
+
+    Maximum and minimum energy.
+
+  It may be noted that the formula (30) gives immediate proof of two
+  important theorems due to Bertrand and to Lord Kelvin respectively.
+  Let us suppose, in the first place, that the system is started by
+  given impulses of certain types, but is otherwise free. J.L.F.
+  Bertrand's theorem is to the effect that the kinetic energy is
+  _greater_ than if by impulses of the remaining types the system were
+  constrained to take any other course. We may suppose the co-ordinates
+  to be so chosen that the constraint is expressed by the vanishing of
+  the velocities q`1, q`2, ... q`_m, whilst the given impulses are
+  [kappa], [kappa]', [kappa]",... Hence the energy in the actual motion
+  is greater than in the constrained motion by the amount [@].
+
+  Again, suppose that the system is started with prescribed velocity
+  components q`1, q`2, ... q`_m, by means of proper impulses of
+  the corresponding types, but is otherwise free, so that in the motion
+  actually generated we have [kappa] = 0, [kappa]' = 0, [kappa]" = 0,
+  ... and therefore K = 0. The kinetic energy is therefore _less_ than
+  in any other motion consistent with the prescribed velocity-conditions
+  by the value which K assumes when [kappa], [kappa]', [kappa]", ...
+  represent the impulses due to the constraints.
+
+  Simple illustrations of these theorems are afforded by the chain of
+  straight links already employed. Thus if a point of the chain be held
+  fixed, or if one or more of the joints be made rigid, the energy
+  generated by any given impulses is less than if the chain had
+  possessed its former freedom.
+
+
+  2. _Continuous Motion of a System._
+
+    Lagrange's equations.
+
+  We may proceed to the continuous motion of a system. The equations of
+  motion of any particle of the system are of the form
+
+    mx" = X, my" = Y, mz" = Z  (1)
+
+  Now let x + [delta]x, y + [delta]y, z + [delta]z be the co-ordinates
+  of m in any arbitrary motion of the system differing infinitely little
+  from the actual motion, and let us form the equation
+
+    [Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z) =
+       [Sigma](X[delta]x + Y[delta]y + Z[delta]z) (2)
+
+  Lagrange's investigation consists in the transformation of (2) into an
+  equation involving the independent variations [delta]q1, [delta]q2,
+  ... [delta]q_n.
+
+  It is important to notice that the symbols [delta] and d/dt are
+  commutative, since
+
+                d                  dx   d
+    [delta]x` = --(x + [delta]x) - -- = --[delta]x, &c. (3)
+                dt                 dt   dt
+
+  Hence
+
+                                                     d
+    [Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z) = -- [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)
+                                                     dt
+      - [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)
+
+        d
+      = --(p1[delta]q1 + p2[delta]q2 + ...) - [delta][Tau],  (4)
+        dt
+
+  by Sec. 1 (14). The last member may be written
+
+    p`1[delta]q1 + p1[delta]q`1 + p`2[delta]q2 + p2[delta]q`2 + ...
+
+        dP[Tau]              dP[Tau]             dP[Tau]              dP[Tau]
+      - ------- [delta]q`1 - ------- [delta]q1 - ------- [delta]q`2 - ------- [delta]q2 - ... (5)
+         dPq`1                dPq1                dPq`2                dPq2
+
+  Hence, omitting the terms which cancel in virtue of Sec. 1 (13), we find
+
+                                                      /     dP[Tau]\               /     dP[Tau]\
+    [Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z) = (p`1 - ------- ) [delta]q1 + (p`2 - ------- ) [delta]q2 + ... (6)
+                                                      \      dPq1  /               \       dPq2 /
+
+  For the right-hand side of (2) we have
+
+    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = Q1[delta]q1 + Q2[delta]q2  + ..., (7)
+
+                      /   dPx       dPy       dPz \
+  where Q_r = [Sigma]( X ----- + Y ----- + Z ----- )  (8)
+                      \  dPq_r     dPq_r     dPq_r/
+
+  The quantities Q1, Q2, ... are called the _generalized components of
+  force_ acting on the system.
+
+  Comparing (6) and (7) we find
+
+          dP[Tau]             dP[Tau]
+    p`1 - ------- = Q1, p`2 - ------- = Q2, ...,  (9)
+           dPq`1               dPq`2
+
+  or, restoring the values of p1, p2, ...,
+
+    d   /dP[Tau]\    dP[Tau]       d   /dP[Tau]\    dP[Tau]
+    -- ( ------- ) - ------- = Q1, -- ( ------- ) - ------- = Q2, ... (10)
+    dt  \ dPq`1 /     dPq1         dt  \ dPq`2 /      dPq2
+
+  These are Lagrange's general equations of motion. Their number is of
+  course equal to that of the co-ordinates q1, q2, ... to be determined.
+
+  Analytically, the above proof is that given by Lagrange, but the
+  terminology employed is of much more recent date, having been first
+  introduced by Lord Kelvin and P.G. Tait; it has greatly promoted the
+  physical application of the subject. Another proof of the equations
+  (10), by direct transformation of co-ordinates, has been given by
+  Hamilton and independently by other writers (see MECHANICS), but the
+  variational method of Lagrange is that which stands in closest
+  relation to the subsequent developments of the subject. The chapter of
+  Maxwell, already referred to, is a most instructive commentary on the
+  subject from the physical point of view, although the proof there
+  attempted of the equations (10) is fallacious.
+
+  In a "conservative system" the work which would have to be done by
+  extraneous forces to bring the system from rest in some standard
+  configuration to rest in the configuration (q1, q2, ... q_n) is
+  independent of the path, and may therefore be regarded as a definite
+  function of q1, q2, ... q_n. Denoting this function (the _potential
+  energy_) by V, we have, if there be no extraneous force on the system,
+
+    [Sigma](X[delta]x + Y[delta]y + Z[delta]z) = - [delta]V,  (11)
+
+  and therefore
+
+           dPV          dPV
+    Q1 = - ----, Q2 = - ----, ....  (12)
+           dPq1         dPq2
+
+  Hence the typical Lagrange's equation may be now written in the form
+
+    d   /dP[Tau]\    dP[Tau]      dPV
+    -- ( ------- ) - ------- = - -----,  (13)
+    dt  \dPq`_r /     dPq_r      dPq_r
+
+  or, again,
+
+              dP
+    p`_r = - ----- (V - [Tau])  (14)
+             dPq_r
+
+  It has been proposed by Helmholtz to give the name _kinetic potential_
+  to the combination V - [Tau].
+
+  As shown under MECHANICS, Sec. 22, we derive from (10)
+
+    d[Tau]
+    ------ = Q1q`1 + Q2q`2 + ...,  (15)
+      dt
+
+  and therefore in the case of a conservative system free from
+  extraneous force,
+
+    d
+    --([Tau] + V) = 0 or [Tau] + V = const.,  (16)
+    dt
+
+  which is the equation of energy. For examples of the application of
+  the formula (13) see MECHANICS, Sec. 22.
+
+
+  3. _Constrained Systems._
+
+    Case of varying relations.
+
+  It has so far been assumed that the geometrical relations, if any,
+  which exist between the various parts of the system are of the type Sec.
+  1 (1), and so do not contain t explicitly. The extension of Lagrange's
+  equations to the case of "varying relations" of the type
+
+    x = f(t, q1, q2,...q_n), y = &c., z = &c.,  (1)
+
+  was made by J.M.L. Vieille. We now have
+
+         dPx   dPx        dPx
+    x` = --- + ---- q`1 + ---- q`2 + ..., &c., &c.,  (2)
+         dPt   dPq1       dPq2
+
+          dPx              dPx
+    dPx = ---- [delta]q1 + ---- [delta]q2 + ..., &c., &c.,  (3)
+          dPq1             dPq2
+
+  so that the expression Sec. 1 (8) for the kinetic energy is to be
+  replaced by
+
+    2[Tau] = [alpha]0 + 2[alpha]1q`1 + 2[alpha]2q`2 + ... + A11q`1 squared + A22q`2 squared + ... + A12q`1q`2 + ..., (4)
+
+  where
+                   _                           _         \
+                  | /dPx\ squared    /dPy\ squared    /dPz\ squared  |         |
+    a0 = [Sigma]m |( --- ) + ( --- ) + ( --- )  |,        |
+                  |_\dPt/     \dPt/     \dPt/  _|         |
+                    _                                 _    >  (5)
+                   | dPx  dPx    dPy  dPy    dPz  dPz  |  |
+    a_r = [Sigma]m | --- ----- + --- ----- + --- ----- |, |
+                   |_dPt dPq_r   dPt dPq_r   dPt dPq_r_|  |
+                                                         /
+
+  and the forms of A_rr, A_rs are as given by Sec. 1 (7). It is to be
+  remembered that the coefficients [alpha]0, [alpha]1, [alpha]2, ...
+  A11, A22, ... A12 ... will in general involve t explicitly as well as
+  implicitly through the co-ordinates q1, q2,... Again, we find
+
+    [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) =
+
+        ([alpha]1 + A11q`1 + A12q`2 + ...)[delta]q1
+            + ([alpha]2 + A21q`1 + A22q`2 + ...)dPq2 + ...
+
+          dP[Tau]             dP[Tau]
+        = ------- [delta]q1 + ------- [delta]q2 + ...
+           dPq`1               dPq`2
+
+        = p1[delta]q1 + p2[delta]q2 + ...,  (6)
+
+  where p_r is defined as in Sec. 1 (13). The derivation of Lagrange's
+  equations then follows exactly as before. It is to be noted that the
+  equation Sec. 2 (15) does not as a rule now hold. The proof involved the
+  assumption that [Tau] is a homogeneous quadratic function of the
+  velocities q`1, q`2....
+
+  It has been pointed out by R.B. Hayward that Vieille's case can be
+  brought under Lagrange's by introducing a new co-ordinate ([chi]) in
+  place of t, so far as it appears explicitly in the relations (1). We
+  have then
+
+    2[Tau] = [alpha]0[chi]` squared + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
+        + A11q`1 squared + A22q`2 squared + ... + 2A12q`1q`2 + .... (7)
+
+  The equations of motion will be as in Sec. 2 (10), with the additional
+  equation
+
+    d  dP[Tau]    dP[Tau]
+    -- -------- - ------- = X,  (8)
+    dt dP[chi]`   dP[chi]
+
+  where X is the force corresponding to the co-ordinate [chi]. We may
+  suppose X to be adjusted so as to make [chi]" = 0, and in the
+  remaining equations nothing is altered if we write t for [chi] before,
+  instead of after, the differentiations. The reason why the equation Sec.
+  2 (15) no longer holds is that we should require to add a term X[chi]`
+  on the right-hand side; this represents the rate at which work is
+  being done by the constraining forces required to keep [chi]`
+  constant.
+
+  As an example, let x, y, z be the co-ordinates of a particle relative
+  to axes fixed in a solid which is free to rotate about the axis of z.
+  If [phi] be the angular co-ordinate of the solid, we find without
+  difficulty
+
+    2[Tau] = m(x` squared + y` squared +z` squared) + 2[phi]`m(xy` - yx`) + {I + m(x squared + y squared)}[phi]` squared, (9)
+
+  where I is the moment of inertia of the solid. The equations of
+  motion, viz.
+
+    d  dP[Tau]  dP[Tau]     d  dP[Tau]   dP[Tau]      d  dP[Tau]   dP[Tau]
+    -- ------ - ------ = X, -- ------- - ------- = Y, -- ------- - ------- = Z, (10)
+    dt  dPx`     dPx        dt   dPy`      dPy        dt   dPz`      dPz
+
+      d   dP[Tau]   dP[Tau]
+  and -- -------- - ------- = [Phi],  (11)
+      dt dP[phi]`   dP[phi]
+
+  become
+
+    m(x" - 2[phi]`y` - x[phi]` squared - y[phi]") = X, m(y" + 2[phi]`x` - y[phi]` squared + x[phi]`) = Y, mz" = Z, (12)
+          _                                    _
+      d  | /            \                       |
+  and -- |(I + m(x squared + y squared)) [phi]` + m(xy` - yx`)| = [Phi].  (13)
+      dt |_\            /                      _|
+
+  If we suppose [Phi] adjusted so as to maintain [phi]" = 0, or (again)
+  if we suppose the moment of inertia I to be infinitely great, we
+  obtain the familiar equations of motion relative to moving axes, viz.
+
+    m(x" - 2[omega]y` - [omega] squaredx) = X, m(y" + 2[omega]x` - [omega] squaredy) = Y, mz" = Z, (14)
+
+  where [omega] has been written for [phi]. These are the equations
+  which we should have obtained by applying Lagrange's rule at once to
+  the formula
+
+    2[Tau] = m(x` squared + y` squared + z` squared) + 2m[omega](xy` - yx`) + m[omega] squared(x squared + y squared), (15)
+
+  which gives the kinetic energy of the particle referred to axes
+  rotating with the constant angular velocity [omega]. (See MECHANICS, Sec.
+  13.)
+
+  More generally, let us suppose that we have a certain group of
+  co-ordinates [chi], [chi]', [chi]", ... whose absolute values do not
+  affect the expression for the kinetic energy, and that by suitable
+  forces of the corresponding types the velocity-components [chi]`,
+  [chi]`', [chi]`", ... are maintained constant. The remaining
+  co-ordinates being denoted by q1, q2, ... q_n, we may write
+
+    2[Tau] = [@] + [Tau]0 + 2([alpha]1q`1 + [alpha]2q`2 + ...)[chi]`
+        + 2([alpha]'1q`1 + [alpha]'2q`2 + ...)[chi]`' + ...,  (16)
+
+  where [@] is a homogeneous quadratic function of the velocities q`1,
+  q`2, ... q`_n of the type Sec.1 (8), whilst [Tau]0 is a homogeneous
+  quadratic function of the velocities [chi]`,[chi]`', [chi]`", ...
+  alone. The remaining terms, which are bilinear in respect of the two
+  sets of velocities, are indicated more fully. The formulae (10) of Sec. 2
+  give n equations of the type
+
+    d  /dP[@]\     /dP[@]\                                  dP[Tau]0
+    --( ----- ) - ( ----- ) + (r, 1)q`1 + (r, 2)q`2 + ... - -------- = Q_r (17)
+    dt \dPq_r/     \dPq_r/                                    dPq_r
+
+  where
+
+              /dPa_r   dPa_s\           /dPa'_r   dPa'_s\
+    (r, s) = ( ----- - ----- )[chi]` + ( ------ - ------ )[chi]`' + .... (18)
+              \dPq_s   dPq_r/           \dPq_s     dPq_r/
+
+  These quantities (r, s) are subject to the relations
+
+    (r, s) = -(s, r), (r, r) = 0  (19)
+
+  The remaining dynamical equations, equal in number to the co-ordinates
+  [chi], [chi]', [chi]", ..., yield expressions for the forces which
+  must be applied in order to maintain the velocities [chi]`, [chi]`',
+  [chi]`", ... constant; they need not be written down. If we follow the
+  method by which the equation of energy was established in Sec. 2, the
+  equations (17) lead, on taking account of the relations (19), to
+
+    d
+    --([@] - [Tau]0) = Q1q`1 + Q2q`2 + ... + Q_nq`_n,  (20)
+    dt
+
+  or, in case the forces Q_r depend only on the co-ordinates q1, q2, ...
+  q_n and are conservative,
+
+    [@] + V - [Tau]0 = const.  (21)
+
+  The conditions that the equations (17) should be satisfied by zero
+  values of the velocities q`1, q`2, ... q`_n are
+
+            dP[Tau]0
+    Q_r = - --------,  (22)
+             dPq_r
+
+  or in the case of conservative forces
+
+    dP
+    ------ (V - [Tau]0) = 0,  (23)
+    dPq_r
+
+  i.e. the value of V - [Tau]0 must be _stationary_.
+
+
+    Rotating axes.
+
+  We may apply this to the case of a system whose configuration relative
+  to axes rotating with constant angular velocity ([omega]) is defined
+  by means of the n co-ordinates q1, q2, ... q_n. This is important on
+  account of its bearing on the kinetic theory of the tides. Since the
+  Cartesian co-ordinates x, y, z of any particle m of the system
+  relative to the moving axes are functions of q1, q2, ... q_n, of the
+  form Sec. 1 (1), we have, by (15)
+
+    2[@] = [Sigma]m(x` squared + y` squared + z` squared), 2[Tau]0 = [omega] squared[Sigma]m(x squared + y squared),  (24)
+
+                  /  dPy      dPx \
+    a_r= [Sigma]m( x----- - y----- ),  (25)
+                  \ dPq_r    dPq_r/
+
+  whence
+
+                                 dP(x, y)
+    (r, s) = 2[omega].[Sigma]m ------------.  (26)
+                               dP(q_s, q_r)
+
+  The conditions of relative equilibrium are given by (23).
+
+  It will be noticed that this expression V - [Tau]0, which is to be
+  stationary, differs from the true potential energy by a term which
+  represents the potential energy of the system in relation to
+  fictitious "centrifugal forces." The question of stability of relative
+  equilibrium will be noticed later (Sec. 6).
+
+  It should be observed that the remarkable formula (20) may in the
+  present case be obtained directly as follows. From (15) and (14) we
+  find
+
+    d[Tau]   d
+    ------ = --([@] + [Tau]0) + [omega].[Sigma]m(xy" - yx")
+      dt     dt
+
+        d
+      = --([@] - [Tau]0) + [omega].[Sigma](xY - yX).  (27)
+        dt
+
+  This must be equal to the rate at which the forces acting on the
+  system do work, viz. to
+
+    [omega][Sigma](xY - yX) + Q1q`1 + Q2q`2 + ... + Q_nq`_n,
+
+  where the first term represents the work done in virtue of the
+  rotation.
+
+
+    Constrained systems.
+
+  We have still to notice the modifications which Lagrange's equations
+  undergo when the co-ordinates q1, q2, ... q_n are not all
+  independently variable. In the first place, we may suppose them
+  connected by a number m ( < n) of relations of the type
+
+    A(t, q1, q2, ... q_n) = 0, B(t, q1, q2, ... q_n) = 0, &c.  (28)
+
+  These may be interpreted as introducing partial constraints into a
+  previously free system. The variations [delta]q1, [delta]q2, ...
+  [delta]q_n in the expressions (6) and (7) of Sec. 2 which are to be
+  equated are no longer independent, but are subject to the relations
+
+    dPA              dPA                       dPB              dPB
+    ---- [delta]q1 + ---- [delta]q2 + ... = 0, ---- [delta]q1 + ---- [delta]q2 + ... = 0, &c.  (29)
+    dPq1             dPq2                      dPq1             dPq2
+
+  Introducing indeterminate multipliers [lambda],  mu, ..., one for each
+  of these equations, we obtain in the usual manner n equations of the
+  type
+
+    d  dP[Tau]   dP[Tau]                   dPA       dPB
+    -- ------- - ------- = Q_r + [lambda] ----- +  mu ----- + ..., (30)
+    dt dPq`_r     dPq_r                   dPq_r     dPq_r
+
+  in place of Sec. 2 (10). These equations, together with (28), serve to
+  determine the n co-ordinates q1, q2, ... q_n and the m multipliers
+  [lambda],  mu, ....
+
+  When t does not occur explicitly in the relations (28) the system is
+  said to be _holonomic_. The term connotes the existence of integral
+  (as opposed to differential) relations between the co-ordinates,
+  independent of the time.
+
+  Again, it may happen that although there are no prescribed relations
+  between the co-ordinates q1, q2, ... q_n, yet from the circumstances
+  of the problem certain geometrical conditions are imposed on their
+  _variations_, thus
+
+    A1[delta]q1 + A2[delta]q2 + ... = 0, B1[delta]q1 + B2[delta]q2 + ... = 0, &c., (31)
+
+  where the coefficients are functions of q1, q2, ... q_n and (possibly)
+  of t. It is assumed that these equations are not integrable as regards
+  the variables q1, q2, ... q_n; otherwise, we fall back on the previous
+  conditions. Cases of the present type arise, for instance, in ordinary
+  dynamics when we have a solid rolling on a (fixed or moving) surface.
+  The six co-ordinates which serve to specify the position of the solid
+  at any instant are not subject to any necessary relation, but the
+  conditions to be satisfied at the point of contact impose three
+  conditions of the form (31). The general equations of motion are
+  obtained, as before, by the method of indeterminate multipliers, thus
+
+    d  dP[Tau]   dP[Tau]
+    -- ------- - ------- = Q_r + [lambda]A_r +  muB_r + ...  (32)
+    dt dPq`_r     dPq_r
+
+  The co-ordinates q1, q2, ... q_n, and the indeterminate multipliers
+  [lambda],  mu, ..., are determined by these equations and by the
+  velocity-conditions corresponding to (31). When t does not appear
+  explicitly in the coefficients, these velocity-conditions take the
+  forms
+
+    A1q`1 + A2q`2 + ... = 0, B1q`1 + B2q`2 + ... = 0, &c.  (33)
+
+  Systems of this kind, where the relations (31) are not integrable, are
+  called _non-holonomic_.
+
+
+  4. _Hamiltonian Equations of Motion._
+
+  In the Hamiltonian form of the equations of motion of a conservative
+  system with unvarying relations, the kinetic energy is supposed
+  expressed in terms of the _momenta_ p1, p2, ... and the co-ordinates
+  q1, q2, ..., as in Sec. 1 (19). Since the symbol [delta] now denotes a
+  variation extending to the co-ordinates as well as to the momenta, we
+  must add to the last member of Sec. 1 (21) terms of the types
+
+    dP[Tau]             dP[Tau]'
+    ------- [delta]q1 + -------- [delta]q1 + ...  (1)
+     dPq1                 dPq1
+
+  Since the variations [delta]p1, [delta]p2, ... [delta]q1, [delta]q2,
+  ... may be taken to be independent, we infer the equations Sec. 1 (23) as
+  before, together with
+
+    dP[Tau]    dP[Tau]'  dP[Tau]     dP[Tau]'
+    ------ = - --------, ------- = - --------, ...,  (2)
+     dPq1        dPq1     dPq2         dPq2
+
+  Hence the Lagrangian equations Sec. 2 (14) transform into
+
+             dP                      dP
+    p`1 = - ----([Tau]' + V), p`2 = ---- ([Tau]' + V), ...  (3)
+            dPq1                    dPq2
+
+  If we write
+
+    H = [Tau]' + V,  (4)
+
+  so that H denotes the _total energy_ of the system, supposed expressed
+  in terms of the new variables, we get
+
+            dPH           dPH
+    p`1 = - ----, p`2 = - ----, ...  (5)
+            dPq1          dPq2
+
+  If to these we join the equations
+
+          dPH         dPH
+    q`1 = ----, q`2 = ----, ...,  (6)
+          dPp1        dPp2
+
+
+  which follow at once from Sec. 1 (23), since V does not involve p1, p2,
+  ..., we obtain a complete system of differential equations _of the
+  first order_ for the determination of the motion.
+
+  The equation of energy is verified immediately by (5) and (6), since
+  these make
+
+    dH   dPH        dPH              dPH        dPH
+    -- = ---- p`1 + ---- p`2 + ... + ---- q`1 + ---- q`2 + ... = 0. (7)
+    dt   dPp1       dPp2             dPq1       dPq2
+
+  The Hamiltonian transformation is extended to the case of varying
+  relations as follows. Instead of (4) we write
+
+    H = p1q`1 + p2q`2 + ... - [Tau] + V,  (8)
+
+  and imagine H to be expressed in terms of the momenta p1, p2, ..., the
+  co-ordinates q1, q2, ..., and the time. The internal forces of the
+  system are assumed to be conservative, with the potential energy V.
+  Performing the variation [delta] on both sides, we find
+
+                                    dP[Tau]             dPV
+    [delta]H = q`1[delta]p1 + ... - ------- [delta]q1 + ---- [delta]q + ...,  (9)
+                                     dPq1               dPq1
+
+  terms which cancel in virtue of the definition of p1, p2, ... being
+  omitted. Since [delta]p1, [delta]p2, ..., [delta]q1, [delta]q2, ...
+  may be taken to be independent, we infer
+
+          dPH         dPH
+    q`1 = ----, q`2 = ----, ...,  (10)
+          dPp1        dPp2
+
+  and
+
+     dP                  dPH    dP                 dPH
+    ---- ([Tau] - V) = - ----, ----([Tau] - V) = - ----, ....  (11)
+    dPq1                 dPq1  dPq2                dPq2
+
+  It follows from (11) that
+
+            dPH           dPH
+    p`1 = - ----, p`2 = - ----, ....  (12)
+            dPq1          dPq2
+
+  The equations (10) and (12) have the same form as above, but H is no
+  longer equal to the energy of the system.
+
+
+  5. _Cyclic Systems._
+
+  A _cyclic_ or _gyrostatic_ system is characterized by the following
+  properties. In the first place, the kinetic energy is not affected if
+  we alter the absolute values of certain of the co-ordinates, which we
+  will denote by [chi], [chi]', [chi]", ..., provided the remaining
+  co-ordinates q1, q2, ... q_m and the velocities, including of course
+  the velocities [.[chi]], [.[chi]]', [.[chi]]", ..., are unaltered.
+  Secondly, there are no forces acting on the system of the types [chi],
+  [chi]', [chi]", .... This case arises, for example, when the system
+  includes gyrostats which are free to rotate about their axes, the
+  co-ordinates [chi], [chi]', [chi]", ... then being the angular
+  co-ordinates of the gyrostats relatively to their frames. Again, in
+  theoretical hydrodynamics we have the problem of moving solids in a
+  frictionless liquid; the ignored co-ordinates [chi], [chi]', [chi]",
+  ... then refer to the fluid, and are infinite in number. The same
+  question presents itself in various physical speculations where
+  certain phenomena are ascribed to the existence of _latent motions_ in
+  the ultimate constituents of matter. The general theory of such
+  systems has been treated by E.J. Routh, Lord Kelvin, and H.L.F.
+  Helmholtz.
+
+
+    Routh's equations.
+
+  If we suppose the kinetic energy [Tau] to be expressed, as in
+  Lagrange's method, in terms of the co-ordinates and the velocities,
+  the equations of motion corresponding to [chi], [chi]', [chi]'', ...
+  reduce, in virtue of the above hypotheses, to the forms
+
+    d  dP[Tau]        d   dP[Tau]       d   dP[Tau]
+    -- --------- = 0, -- --------- = 0, -- --------- = 0, ...,  (1)
+    dt dP[chi]`       dt dP[chi]`'      dt dP[chi]`"
+
+  whence
+
+     dP[Tau]             dP[Tau]               dP[Tau]
+    -------- = [kappa], --------- = [kappa]', --------- = [kappa]", ..., (2)
+    dP[chi]`            dP[chi]`'             dP[chi]`"
+
+  where [kappa], [kappa]', [kappa]", ... are the constant momenta
+  corresponding to the cyclic co-ordinates [chi], [chi]', [chi]", ....
+  These equations are linear in [.[chi]], [.[chi]]', [.[chi]]", ...;
+  solving them with respect to these quantities and substituting in the
+  remaining Lagrangian equations, we obtain m differential equations to
+  determine the remaining co-ordinates q1, q2, ... q_m. The object of
+  the present investigation is to ascertain the general form of the
+  resulting equations. The retained co-ordinates q1, q2, ... q_m may be
+  called (for distinction) the _palpable_ co-ordinates of the system; in
+  many practical questions they are the only co-ordinates directly in
+  evidence.
+
+  If, as in Sec. 1 (25), we write
+
+    R = [Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ..., (3)
+
+  and imagine R to be expressed by means of (2) as a quadratic function
+  of q`1, q`2, ... q`_m, [kappa], [kappa]', [kappa]", ... with
+  coefficients which are in general functions of the co-ordinates q1,
+  q2, ... q_m, then, performing the operation [delta] on both sides, we
+  find
+
+     dPR                       dPR                          dPR                   dP[Tau]                   dP[Tau]
+    -----[delta]q`1 + ... + ---------[delta][kappa] + ... + ----[delta]q1 + ... = -------[delta]q`1 + ... + -------[delta]q1 + ...
+    dPq`1                   dP[kappa]                       dPq1                   dPq`1                     dPq1
+
+         dP[Tau]                      dP[Tau]
+      + --------[delta][chi]` + ... + --------[delta]q1 + ... - [kappa][delta][chi]` - [chi]`[delta][kappa] - .... (4)
+        dP[chi]`                      dP[chi]1
+
+  Omitting the terms which cancel by (2), we find
+
+    dP[Tau]    dPR   dP[Tau]    dPR
+    ------- = -----, ------- = -----, ...,  (5)
+     dPq`1    dPq`1   dPq`2    dPq`2
+
+    dP[Tau]   dPR   dP[Tau]   dPR
+    ------- = ----, ------- = ----, ...,  (6)
+     dPq1     dPq1   dPq2     dPq2
+
+                    dPR                    dPR                     dPR
+    [chi]`  =  - ---------, [chi]`' = - ----------, [chi]`" = - ----------, ... (7)
+                 dP[kappa]              dP[kappa]'              dP[kappa]"
+
+  Substituting in Sec. 2 (10), we have
+
+    d   dPR     dPR        d   dPR    dPR
+    -- ----- - ----- = Q1, -- ----- - ---- = Q2, ...  (8)
+    dt dPq`1   dPq1        dt dPq`2   dPq2
+
+  These are Routh's forms of the modified Lagrangian equations.
+  Equivalent forms were obtained independently by Helmholtz at a later
+  date.
+
+
+    Kelvin's equations.
+
+  The function R is made up of three parts, thus
+
+    R = R(2,0) + R(1,1) + R(0,2), ...  (9)
+
+  where R(2,0) is a homogeneous quadratic function of q`1, q`2, ...
+  q`_m, R(0,2) is a homogeneous quadratic function of [kappa], [kappa]',
+  [kappa]", ..., whilst R(1,1) consists of products of the velocities
+  q`1, q`2, ... q`_m into the momenta [kappa], [kappa]', [kappa]"....
+  Hence from (3) and (7) we have
+
+                 /           dPR                 dPR                   dPR         \
+    [Tau] = R - ( [kappa] --------- + [kappa]'---------- + [kappa]" ---------- + ...)
+                 \        dP[kappa]           dP[kappa]'            dP[kappa]"     /
+
+      = R(2,0) - R(0,2).  (10)
+
+  If, as in Sec. 1 (30), we write this in the form
+
+    [Tau] = [@] + [Kappa],  (11)
+
+  then (3) may be written
+
+    R = [@] - [Kappa] + ss1q`1 + ss2q`2 + ...,  (12)
+
+  where ss1, ss2, ... are linear functions of [kappa], [kappa]', [kappa]",
+  ..., say
+
+    ss_r = [alpha]_r[kappa] + [alpha]'_r[kappa]' + [alpha]"_r[kappa]" + ..., (13)
+
+  the coefficients [alpha]_r, [alpha]'_r, [alpha]"_r, ... being in
+  general functions of the co-ordinates q1, q2, ... q_m. Evidently ss_r
+  denotes that part of the momentum-component dPR/dPq`_r which is due to
+  the cyclic motions. Now
+
+    d   dPR      d  / dP[@]     \    d   dP[@]   dPss_r      dPss_r
+    -- ------ = -- ( ------ + ss_r) = -- ------ + -----q`1 + -----q`2 + ..., (14)
+    dt dPq`_r   dt  \dPq`_r     /    dt dPq`_r    dPq1       dPq2
+
+     dPR    dP[@]   dP[Kappa]   dPss1       dPss2
+    ----- = ----- - --------- + -----q`1 + -----q`2 + .... (15)
+    dPq_r   dPq_r     dPq_r     dPq_r      dPq_r
+
+  Hence, substituting in (8), we obtain the typical equation of motion
+  of a gyrostatic system in the form
+
+    d   dP[@]   dP[@]                                                    dP[Kappa]
+    -- ------ - ----- + (r, 1)q`1 + (r, 2)q`2 + ... + (r, s)q`_s + ... + --------- = Q_r, (16)
+    dt dPq`_r   dPq_r                                                      dPq_r
+
+  where
+
+             dPss_r   dPss_s
+    (r, s) = ----- - -----.  (17)
+             dPq_s   dPq_r
+
+  This form is due to Lord Kelvin. When q1, q2, ... q_m have been
+  determined, as functions of the time, the velocities corresponding to
+  the cyclic co-ordinates can be found, if required, from the relations
+  (7), which may be written
+
+             dP[Kappa]                                        \
+    [Chi]` = --------- - [alpha]1q`1 - [alpha]2q`2 - ...,     |
+             dP[kappa]                                        |
+                                                              |
+              dP[Kappa]                                        >  (18)
+    [Chi]`' = ---------- - [alpha]'1q`1 - [alpha]'2q`2 - ..., |
+              dP[kappa]'                                      |
+                                                              |
+       &c., &c.                                               /
+
+  It is to be particularly noticed that
+
+    (r, r) = 0, (r, s) = -(s, r).  (19)
+
+  Hence, if in (16) we put r = 1, 2, 3, ... m, and multiply by q`1,
+  q`2, ... q`_m respectively, and add, we find
+
+    d
+    --([@] + [Kappa]) = Q1q`1 + Q2q`2 + ...,  (20)
+    dt
+
+  or, in the case of a conservative system
+
+    [@] + V + [Kappa] = const.,  (21)
+
+  which is the equation of energy.
+
+  The equation (16) includes Sec. 3 (17) as a particular case, the
+  eliminated co-ordinate being the angular co-ordinate of a rotating
+  solid having an infinite moment of inertia.
+
+  In the particular case where the cyclic momenta [kappa], [kappa]',
+  [kappa]", ... are all zero, (16) reduces to
+
+    d   dP[@]   dP[@]
+    -- ------ - ----- = Q_r.  (22)
+    dt dPq`_r   dPq_r
+
+  The form is the same as in Sec. 2, and the system now behaves, as regards
+  the co-ordinates q1, q2, ... q_m, exactly like the acyclic type there
+  contemplated. These co-ordinates do not, however, now fix the position
+  of every particle of the system. For example, if by suitable forces
+  the system be brought back to its initial configuration (so far as
+  this is defined by q1, q2, ..., q_m), after performing any evolutions,
+  the ignored co-ordinates [chi], [chi]', [chi]", ... will not in
+  general return to their original values.
+
+  If in Lagrange's equations Sec. 2 (10) we reverse the sign of the
+  time-element dt, the equations are unaltered. The motion is therefore
+  reversible; that is to say, if as the system is passing through any
+  configuration its velocities q`1, q`2, ..., q`_m be all
+  reversed, it will (if the forces be the same in the same
+  configuration) retrace its former path. But it is important to observe
+  that the statement does not in general hold of a gyrostatic system;
+  the terms of (16), which are linear in q`1, q`2, ..., q`_m,
+  change sign with dt, whilst the others do not. Hence the motion of a
+  gyrostatic system is not reversible, unless indeed we reverse the
+  cyclic motions as well as the velocities q`1, q`2, ..., q`_m.
+  For instance, the precessional motion of a top cannot be reversed
+  unless we reverse the spin.
+
+
+    Kinetostatics.
+
+  The _conditions of equilibrium_ of a system with latent cyclic motions
+  are obtained by putting q`1 = 0, q`2 = 0, ... q`_m = 0 in (16); viz.
+  they are
+
+         dP[Kappa]       dP[Kappa]
+    Q1 = ---------, Q2 = ---------, ...  (23)
+           dPq1            dPq2
+
+  These may of course be obtained independently. Thus if the system be
+  guided from (apparent) rest in the configuration (q1, q2, ... q_m) to
+  rest in the configuration q1 + [delta]q1, q2 + [delta]q2, ..., q_m +
+  [delta]q_m, the work done by the forces must be equal to the increment
+  of the kinetic energy. Hence
+
+    Q1[delta]q1 + Q2[delta]q2 + ... = [delta][Kappa],  (24)
+
+  which is equivalent to (23). The conditions are the same as for the
+  equilibrium of a system without latent motion, but endowed with
+  potential energy [Kappa]. This is important from a physical point of
+  view, as showing how energy which is apparently potential may in its
+  ultimate essence be kinetic.
+
+  By means of the formulae (18), which now reduce to
+
+             dP[Kappa]            dP[Kappa]             dP[Kappa]
+    [chi]` = ---------, [chi]`' = ----------, [chi]`" = ---------- ..., (25)
+             dP[kappa]            dP[kappa]'            dP[kappa]"
+
+  [Kappa] may also be expressed as a homogeneous quadratic function of
+  the cyclic velocities [.[chi]], [.[chi]]', [.[chi]]", ... Denoting it
+  in this form by [Tau]0, we have
+
+    [delta]([Tau]0 + [Kappa] = 2[delta][Kappa] = [delta]([kappa] [chi]` + [kappa]'[chi]`' + [kappa]"[chi]`" +  ...). (26)
+
+  Performing the variations, and omitting the terms which cancel by (2)
+  and (25), we find
+
+    dP[Tau]0     dP[Kappa]  dP[Tau]0     dP[Kappa]
+    -------- = - ---------, -------- = - ---------, ...,  (27)
+      dPq1         dPq1       dPq2         dPq2
+
+  so that the formulae (23) become
+
+           dP[Tau]0         dP[Tau]0
+    Q1 = - --------, Q2 = - --------, ...  (28)
+             dPq1             dPq2
+
+  A simple example is furnished by the top (MECHANICS, Sec. 22). The cyclic
+  co-ordinates being [psi], [phi], we find
+
+                                  ( mu - [nu] cos [theta]) squared   [nu] squared
+    2[@] = A[theta]` squared, 2[Kappa] = ----------------------- + -----,
+                                      A sin squared [theta]          C
+
+      2[Tau]0 = A sin squared[theta][psi]` squared + C([phi]` + [psi] cos [theta]) squared, (29)
+
+  whence we may verify that dP[Tau]0/dP[theta] = - dP[Kappa]/dP[theta]
+  in accordance with (27). And the condition of equilibrium
+
+    dP[Kappa]        dPV
+    --------- = - ---------  (30)
+    dP[theta]     dP[theta]
+
+  gives the condition of steady precession.
+
+
+  6. _Stability of Steady Motion._
+
+  The small oscillations of a conservative system about a configuration
+  of equilibrium, and the criterion of stability, are discussed in
+  MECHANICS, Sec. 23. The question of the stability of given types of
+  motion is more difficult, owing to the want of a sufficiently general,
+  and at the same time precise, definition of what we mean by
+  "stability." A number of definitions which have been propounded by
+  different writers are examined by F. Klein and A. Sommerfeld in their
+  work _Ueber die Theorie des Kreisels_ (1897-1903). Rejecting previous
+  definitions, they base their criterion of stability on the character
+  of the changes produced in the _path_ of the system by small arbitrary
+  disturbing impulses. If the undisturbed path be the _limiting form_ of
+  the disturbed path when the impulses are indefinitely diminished, it
+  is said to be stable, but not otherwise. For instance, the vertical
+  fall of a particle under gravity is reckoned as stable, although for a
+  _given_ impulsive disturbance, however small, the deviation of the
+  particle's position at any time t from the position which it would
+  have occupied in the original motion increases indefinitely with t.
+  Even this criterion, as the writers quoted themselves recognize, is
+  not free from ambiguity unless the phrase "limiting form," as applied
+  to a path, be strictly defined. It appears, moreover, that a
+  definition which is analytically precise may not in all cases be easy
+  to reconcile with geometrical prepossessions. Thus a particle moving
+  in a circle about a centre of force varying inversely as the cube of
+  the distance will if slightly disturbed either fall into the centre,
+  or recede to infinity, after describing in either case a spiral with
+  an infinite number of convolutions. Each of these spirals has,
+  analytically, the circle as its limiting form, although the motion in
+  the circle is most naturally described as unstable.
+
+  A special form of the problem, of great interest, presents itself in
+  the steady motion of a gyrostatic system, when the non-eliminated
+  co-ordinates q1, q2, ... q_m all vanish (see Sec. 5). This has been
+  discussed by Routh, Lord Kelvin and Tait, and Poincare. These writers
+  treat the question, by an extension of Lagrange's method, as a problem
+  of small oscillations. Whether we adopt the notion of stability which
+  this implies, or take up the position of Klein and Sommerfeld, there
+  is no difficulty in showing that stability is ensured if V + [Kappa]
+  be a minimum as regards variations of q1, q2, ... q_m. The proof is
+  the same as that of Dirichlet for the case of statical stability.
+
+  We can illustrate this condition from the case of the top, where, in
+  our previous notation,
+
+                                   ( mu - [nu]cos [theta]) squared   [nu] squared
+    V + [Kappa] = Mgh cos[theta] + ---------------------- + -----. (1)
+                                       2A sin squared [theta]       2C
+
+  To examine whether the steady motion with the centre of gravity
+  vertically above the pivot is stable, we must put  mu = [nu]. We then
+  find without difficulty that V + [Kappa] is a minimum provided [nu] squared
+  [>=] 4AMgh. The method of small oscillations gave us the condition
+  [nu] squared > 4AMgh, and indicated instability in the cases [nu] squared [=<]
+  4AMgh. The present criterion can also be applied to show that the
+  steady precessional motions in which the axis has a constant
+  inclination to the vertical are stable.
+
+  The question remains, as before, whether it is _essential_ for
+  stability that V + [Kappa] should be a minimum. It appears that from
+  the point of view of the theory of small oscillations it is not
+  essential, and that there may even be stability when V + [Kappa] is a
+  maximum. The precise conditions, which are of a somewhat elaborate
+  character, have been formulated by Routh. An important distinction
+  has, however, been established by Thomson and Tait, and by Poincare,
+  between what we may call _ordinary_ or _temporary_ stability (which is
+  stability in the above sense) and _permanent_ or _secular_ stability,
+  which means stability when regard is had to possible dissipative
+  forces called into play whenever the co-ordinates q1, q2, ... q_m
+  vary. Since the total energy of the system at any instant is given (in
+  the notation of Sec. 5) by an expression of the form [@] + V +
+  [Kappa], where [@] cannot be negative, the argument of Thomson
+  and Tait, given under MECHANICS, Sec. 23, for the statical question,
+  shows that it is a necessary as well as a sufficient condition for
+  secular stability that V + [Kappa] should be a minimum. When a system
+  is "ordinarily" stable, but "secularly" unstable, the operation of the
+  frictional forces is to induce a gradual increase in the amplitude of
+  the free vibrations which are called into play by accidental
+  disturbances.
+
+  There is a similar theory in relation to the constrained systems
+  considered in Sec. 3 above. The equation (21) there given leads to the
+  conclusion that for secular stability of any type of motion in which
+  the velocities q`1, q`2, ... q`_n are zero it is necessary and
+  sufficient that the function V - [Tau]0 should be a minimum.
+
+  The simplest possible example of this is the case of a particle at the
+  lowest point of a smooth spherical bowl which rotates with constant
+  angular velocity ([omega]) about the vertical diameter. This position
+  obviously possesses "ordinary" stability. If a be the radius of the
+  bowl, and [theta] denote angular distance from the lowest point, we
+  have
+
+    V - [Tau]0 = mga(1 - cos [theta]) - 1/2m[omega] squareda squared sin squared [theta];  (2)
+
+  this is a minimum for [theta] = 0 only so long as [omega] squared < g/a. For
+  greater values of [omega] the only position of "permanent" stability
+  is that in which the particle rotates with the bowl at an angular
+  distance cos^(-1) (g/[omega] squareda) from the lowest point. To examine the
+  motion in the neighbourhood of the lowest point, when frictional
+  forces are taken into account, we may take fixed ones, in a horizontal
+  plane, through the lowest point. Assuming that the friction varies as
+  the relative velocity, we have
+
+    x" = -p squaredx - k(x` + [omega]y),  \  (3)
+    y" = -p squaredy - k(y` - [omega]x),  /
+
+  where p squared = g/a. These combine into
+
+    z" + kz` + (p squared - ik[omega])z = 0,  (4)
+
+  where z = x + iy, i = [root]-1. Assuming z = Ce^([lambda]t), we find
+
+    [lambda] = -1/2k(1 [-+] [omega]/p) +- ip,  (5)
+
+  if the square of k be neglected. The complete solution is then
+
+    x + iy = C1e^(-ss1t)e^(ipt) + C2e^(-ss2t)e^(-ipt),  (6)
+
+  where ss1 = 1/2k(1 - [omega]/p), ss2 = 1/2k(1 + [omega]/p). (7)
+
+  This represents two superposed circular vibrations, in opposite
+  directions, of period 2[pi]/p. If [omega] < p, the amplitude of each
+  of these diminishes asymptotically to zero, and the position x = 0, y
+  = 0 is permanently stable. But if [omega] > p the amplitude of that
+  circular vibration which agrees in sense with the rotation [omega]
+  will continually increase, and the particle will work its way in an
+  ever-widening spiral path towards the eccentric position of secular
+  stability. If the bowl be not spherical but ellipsoidal, the vertical
+  diameter being a principal axis, it may easily be shown that the
+  lowest position is permanently stable only so long as the period of
+  the rotation is longer than that of the slower of the two normal
+  modes in the absence of rotation (see MECHANICS, Sec. 13).
+
+
+  7. _Principle of Least Action._
+
+    Stationary Action.
+
+  The preceding theories give us statements applicable to the system at
+  any one instant of its motion. We now come to a series of theorems
+  relating to the whole motion of the system between any two
+  configurations through which it passes, viz. we consider the actual
+  motion and compare it with other imaginable motions, differing
+  infinitely little from it, between the same two configurations. We use
+  the symbol [delta] to denote the transition from the actual to any one
+  of the hypothetical motions.
+
+  The best-known theorem of this class is that of _Least Action_,
+  originated by P.L.M. de Maupertuis, but first put in a definite form
+  by Lagrange. The "action" of a single particle in passing from one
+  position to another is the space-integral of the momentum, or the
+  time-integral of the _vis viva_. The action of a dynamical system is
+  the sum of the actions of its constituent particles, and is
+  accordingly given by the formula
+                 _                _            _
+                /                /            /
+    A = [Sigma] | mvds = [Sigma] |  mv squareddt = 2 | [Tau]dt.  (1)
+               _/               _/           _/
+
+  The theorem referred to asserts that the free motion of a conservative
+  system between any two given configurations is characterized by the
+  property
+
+    [delta]A = 0,  (2)
+
+  provided the total energy have the same constant value in the varied
+  motion as in the actual motion.
+
+  If t, t' be the times of passing through the initial and final
+  configurations respectively, we have
+                        _
+                       / t'
+    [delta]A = [delta] |  [Sigma]m(x` squared + y` squared + z` squared)dt
+                      _/t
+                _
+               / t'
+           = 2 |  [delta][Tau]dt + 2[Tau]'[delta]t' + 2[Tau][delta]t, (3)
+              _/t
+
+  since the upper and lower limits of the integral must both be regarded
+  as variable. This may be written
+                _                   _
+               / t'                / t'
+    [delta]A = |  [delta][Tau]dt + |  [Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t
+              _/t                 _/t
+         _                   _                                              _
+        / t'                |                                                | t'
+      = |  [delta][Tau]dt + | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z |
+       _/t                  |_                                              _| t
+           _
+          / t'
+        - |  [Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z)dt + 2[Tau]'[delta]t' - 2[Tau][delta]t. (4)
+         _/t
+
+  Now, by d'Alembert's principle,
+
+    [Sigma]m( x"[delta]x + y"[delta]y + z"[delta]z ) = -[delta]V,  (5)
+
+  and by hypothesis we have
+
+    [delta]([Tau] + V) = 0.  (6)
+
+  The formula therefore reduces to
+                _                                               _
+               |                                                 |t'
+    [delta]A = | [Sigma]m (x`[delta]x + y`[delta]y + z`[delta]z) | + 2[Tau]'[delta]t' - 2[Tau][delta]t. (7)
+               |_                                               _|t
+
+  Since the terminal configurations are unaltered, we must have at the
+  lower limit
+
+    [delta]x + x`[delta]t = 0, [delta]y + y`[delta]t = 0, [delta]z + z`[delta]t = 0, (8)
+
+  with similar relations at the upper limit. These reduce (7) to the
+  form (2).
+
+  The equation (2), it is to be noticed, merely expresses that the
+  variation of A vanishes _to the first order_; the phrase _stationary
+  action_ has therefore been suggested as indicating more accurately
+  what has been proved. The action in the free path between two given
+  configurations is in fact not invariably a minimum, and even when a
+  minimum it need not be the _least possible_ subject to the given
+  conditions. Simple illustrations are furnished by the case of a single
+  particle. A particle moving on a smooth surface, and free from
+  extraneous force, will have its velocity constant; hence the theorem
+  in this case resolves itself into
+             _
+            /
+    [delta] | ds = 0,  (9)
+           _/
+
+  i.e. the path must be a geodesic line. Now a geodesic is not
+  necessarily the _shortest_ path between two given points on it; for
+  example, on the sphere a great-circle arc ceases to be the shortest
+  path between its extremities when it exceeds 180 deg.. More generally,
+  taking any surface, let a point P, starting from O, move along a
+  geodesic; this geodesic will be a minimum path from O to P until P
+  passes through a point O' (if such exist), which is the intersection
+  with a consecutive geodesic through O. After this point the minimum
+  property ceases. On an anticlastic surface two geodesics cannot
+  intersect more than once, and each geodesic is therefore a minimum
+  path between any two of its points. These illustrations are due to
+  K.G.J. Jacobi, who has also formulated the general criterion,
+  applicable to all dynamical systems, as follows:--Let O and P denote
+  any two configurations on a natural path of the system. If this be the
+  sole free path from O to P with the prescribed amount of energy, the
+  action from O to P is a minimum. But if there be several distinct
+  paths, let P vary from coincidence with O along the first-named path;
+  the action will then cease to be a minimum when a configuration O' is
+  reached such that two of the possible paths from O to O' coincide. For
+  instance, if O and P be positions on the parabolic path of a
+  projectile under gravity, there will be a second path (with the same
+  energy and therefore the same velocity of projection from O), these
+  two paths coinciding when P is at the other extremity (O', say) of the
+  focal chord through O. The action from O to P will therefore be a
+  minimum for all positions of P short of O'. Two configurations such as
+  O and O' in the general statement are called conjugate _kinetic foci_.
+  Cf. VARIATIONS, CALCULUS OF.
+
+  Before leaving this topic the connexion of the principle of stationary
+  action with a well-known theorem of optics may be noticed. For the
+  motion of a particle in a conservative field of force the principle
+  takes the form
+             _
+            /
+    [delta] | vds = 0.  (10)
+           _/
+
+  On the corpuscular theory of light v is proportional to the refractive
+  index  mu of the medium, whence
+             _
+            /
+    [delta] |  muds = 0.  (11)
+           _/
+
+
+    Hamiltonian principle.
+
+  In the formula (2) the energy in the hypothetical motion is
+  prescribed, whilst the time of transit from the initial to the final
+  configuration is variable. In another and generally more convenient
+  theorem, due to Hamilton, the time of transit is prescribed to be the
+  same as in the actual motion, whilst the energy may be different and
+  need not (indeed) be constant. Under these conditions we have
+             _
+            /t'
+    [delta] | ([Tau] - V)dt = 0,  (12)
+           _/t
+
+  where t, t' are the prescribed times of passing through the given
+  initial and final configurations. The proof of (12) is simple; we have
+             _                 _                               _
+            /t'               /t'                             /t'
+    [delta] | ([Tau] - V)dt = | ([delta][Tau] - [delta]V)dt = |  {[Sigma]m(x`[delta]x` + y`[delta]y` + z`[delta]z`) - [delta]V}dt
+           _/t               _/t                             _/t
+         _                                              _
+        |                                                |t'
+      = | [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z) |
+        |_                                              _|t
+       _
+      /t'
+    - | {[Sigma]m(x"[delta]x + y"[delta]y + z"[delta]z) + [delta]V}dt (13)
+     _/t
+
+  The integrated terms vanish at both limits, since by hypothesis the
+  configurations at these instants are fixed; and the terms under the
+  integral sign vanish by d'Alembert's principle.
+
+  The fact that in (12) the variation does not affect the time of
+  transit renders the formula easy of application in any system of
+  co-ordinates. Thus, to deduce Lagrange's equations, we have
+
+      _                             _
+     /t'                           /t'/dP[Tau]             dP[Tau]                  dPV               \
+     | ([delta][Tau]-[delta]V)dt = | ( -------[delta]q`1 + -------[delta]q1 + ... - ----[delta]q1 - ...)dt
+    _/t                           _/t \ dPq`1               dPq1                    dPq1              /
+         _                               _
+        |                                 |t'
+      = | p1[delta]q1 + p2[delta]q2 + ... |
+        |_                               _|t
+
+       _  _                                                                        _
+      /t'|  /     dP[Tau]   dPV \              /     dP[Tau]    dPV\                |
+    - |  | (p`1 - ------- + ---- )[delta]q1 + (p`2 - ------- + -----)[delta]q2 + ...|dt. (14)
+     _/t |_ \      dPq1     dPq1/              \      dPq2     dPq2/               _|
+
+  The integrated terms vanish at both limits; and in order that the
+  remainder of the right-hand member may vanish it is necessary that the
+  coefficients of [delta]q1, [delta]q2, ... under the integral sign
+  should vanish for all values of t, since the variations in question
+  are independent, and subject only to the condition of vanishing at the
+  limits of integration. We are thus led to Lagrange's equation of
+  motion for a conservative system. It appears that the formula (12) is
+  a convenient as well as a compact embodiment of the whole of ordinary
+  dynamics.
+
+
+    Extension to cyclic systems.
+
+  The modification of the Hamiltonian principle appropriate to the case
+  of cyclic systems has been given by J. Larmor. If we write, as in Sec. 1
+  (25),
+
+    R = T - [kappa][chi]` - [kappa]'[chi]`' - [kappa]''[chi]`" - ..., (15)
+
+  we shall have
+             _
+            /t'
+    [delta] | (R - V)dt = 0,  (16)
+           _/t
+
+  provided that the variation does not affect the cyclic momenta
+  [kappa], [kappa]', [kappa]", ..., and that the configurations at times
+  t and t' are unaltered, so far as they depend on the palpable
+  co-ordinates q1, q2, ... q_m. The initial and final values of the
+  ignored co-ordinates will in general be affected.
+
+  To prove (16) we have, on the above understandings,
+             _             _
+            /t'           /t'
+    [delta] | (R - V)dt = | ([delta][Tau] - [kappa][delta][chi]` - ... -[delta]V)dt
+           _/t           _/t
+         _
+        /t' /dP[Tau]                   dP[Tau]                          \
+      = |  ( -------[delta]q`1 + ... + -------[delta]q1 + ... - [delta]V )dt,  (17)
+       _/t  \ dPq`1                     dPq1                            /
+
+  where terms have been cancelled in virtue of Sec. 5 (2). The last member
+  of (17) represents a variation of the integral
+      _
+     /t'
+     | ([Tau] - V)dt
+    _/t
+
+  on the supposition that [delta]X = 0, [delta]X' = 0, [delta]X" = 0,
+  ... throughout, whilst [delta]q1, [delta]q2, [delta]q_m vanish at
+  times t and t'; i.e. it is a variation in which the initial and final
+  configurations are absolutely unaltered. It therefore vanishes as a
+  consequence of the Hamiltonian principle in its original form.
+
+  Larmor has also given the corresponding form of the principle of least
+  action. He shows that if we write
+         _
+        /
+    A = |(2[Tau] - [kappa][chi]` - [kappa]'[chi]`' - [kappa]"[chi]`" - ...)dt, (18)
+       _/
+
+  then
+
+    [delta]A = 0,  (19)
+
+  provided the varied motion takes place with the same constant value of
+  the energy, and with the same constant cyclic momenta, between the
+  same two configurations, these being regarded as defined by the
+  palpable co-ordinates alone.
+
+
+  Sec. 8. _Hamilton's Principal and Characteristic Functions._
+
+    Principal function.
+
+  In the investigations next to be described a more extended meaning is
+  given to the symbol [delta]. We will, in the first instance, denote by
+  it an infinitesimal variation of the most general kind, affecting not
+  merely the values of the co-ordinates at any instant, but also the
+  initial and final configurations and the times of passing through
+  them. If we put
+         _
+        /t'
+    S = | (T - V)dt,  (1)
+       _/t
+
+  we have, then,
+                                                       _
+                                                      /t'
+    [delta]S = (T' - V')[delta]t' - (T - V)[delta]t + | ([delta]T - [delta]V)dt
+                                                     _/t
+                                                _                                            _
+                                               |                                              |t'
+      = (T' - V')[delta]t' - (T - V)[delta]t + |[Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z)|  (2)
+                                               |_                                            _|t
+
+  Let us now denote by x' + [delta]x', y' + [delta]y', z' + [delta]z',
+  the final co-ordinates (i.e. at time t' + [delta]t') of a particle m.
+  In the terms in (2) which relate to the upper limit we must therefore
+  write [delta]x' - x`'[delta]t', [delta]y' - y`'[delta]t',
+  [delta]z' - z`'[delta]t' for [delta]x, [delta]y, [delta]z. With a
+  similar modification at the lower limit, we obtain
+
+    [delta]S = - H[delta][tau] + [Sigma]m(x`'[delta]x' + y`'[delta]y' + z`'[delta]z')
+      - [Sigma]m(x`[delta]x + y`[delta]y + z`[delta]z),  (3)
+
+  where H(= T + V) is the constant value of the energy in the free
+  motion of the system, and [tau](= t' - t) is the time of transit. In
+  generalized co-ordinates this takes the form
+
+    [delta]S = - H[delta][tau] + p'1[delta]q'1 + p'2[delta]q'2 + ...
+      - p1[delta]q1 - p2[delta]q2 - ....  (4)
+
+  Now if we select any two arbitrary configurations as initial and
+  final, it is evident that we can in general (by suitable initial
+  velocities or impulses) start the system so that it will of itself
+  pass from the first to the second in any prescribed time [tau]. On
+  this view of the matter, S will be a function of the initial and final
+  co-ordinates (q1, q2, ... and q'1, q'2, ...) and the time [tau], as
+  independent variables. And we obtain at once from (4)
+
+           dPS          dPS        \
+    p'1 = -----, p'2 = -----, ..., |
+          dPq'1        dPq'2       |
+                                    >  (5)
+           dPS          dPS        |
+    p1 = - ----, p2 = - ----, ..., |
+           dPq1         dPq2       /
+
+              dPS
+  and H = - -------.                            (6)
+            dP[tau]
+
+  S is called by Hamilton the _principal function_; if its general form
+  for any system can be found, the preceding equations suffice to
+  determine the motion resulting from any given conditions. If we
+  substitute the values of p1, p2, ... and H from (5) and (6) in the
+  expression for the kinetic energy in the form [Tau]' (see Sec. 1), the
+  equation
+
+    T¹ + V = H  (7)
+
+  becomes a partial differential equation to be satisfied by S. It has
+  been shown by Jacobi that the dynamical problem resolves itself into
+  obtaining a "complete" solution of this equation, involving n + 1
+  arbitrary constants. This aspect of the subject, as a problem in
+  partial differential equations, has received great attention at the
+  hands of mathematicians, but must be passed over here.
+
+
+    Characteristic function.
+
+  There is a similar theory for the function
+           _
+          /
+    A = 2 | Tdt = S + H[tau]  (8)
+         _/
+
+  It follows from (4) that
+
+    [delta]A = [tau][delta]H + p'1[delta]q'1 + p'2[delta]q'2 + ...
+      - p1[delta]q1 - p2[delta]q2 - ....  (9)
+
+  This formula (it may be remarked) contains the principle of "least
+  action" as a particular case. Selecting, as before, any two arbitrary
+  configurations, it is in general possible to start the system from one
+  of these, with a prescribed value of the total energy H, so that it
+  shall pass through the other. Hence, regarding A as a function of the
+  initial and final co-ordinates and the energy, we find
+
+           dPA          dPA        \
+    p'1 = -----, p'2 = -----, ..., |
+          dPq'1        dPq'2       |
+                                    >  (10)
+           dPA          dPA        |
+    p1 = - ----, p2 = - ----, ..., |
+           dPq1         dPq2       /
+
+              dPA
+  and [tau] = ---   (11)
+              dPH
+
+  A is called by Hamilton the _characteristic function_; it represents,
+  of course, the "action" of the system in the free motion (with
+  prescribed energy) between the two configurations. Like S, it
+  satisfies a partial differential equation, obtained by substitution
+  from (10) in (7).
+
+  The preceding theorems are easily adapted to the case of cyclic
+  systems. We have only to write
+         _            _
+        /t'          /t'
+    S = | (R - V)dt= | (T - [kappa][chi]` - [kappa]'[chi]`' - ... - V)dt (12)
+       _/t          _/t
+
+  in place of (1), and
+         _
+        /
+    A = | (2T - [kappa][chi]` - [kappa]'[chi]`' - ...)dt,  (3)
+       _/
+
+  in place of (8); cf. Sec. 7 ad fin. It is understood, of course, that in
+  (12) S is regarded as a function of the initial and final values of
+  the palpable co-ordinates q1, q2, ... q_m, and of the time of transit
+  [tau], the cyclic momenta being invariable. Similarly in (13), A is
+  regarded as a function of the initial and final values of q1, q2, ...
+  q_m, and of the total energy H, with the cyclic momenta invariable. It
+  will be found that the forms of (4) and (9) will be conserved,
+  provided the variations [delta]q1, [delta]q2, ... be understood to
+  refer to the palpable co-ordinates alone. It follows that the
+  equations (5), (6) and (10), (11) will still hold under the new
+  meanings of the symbols.
+
+
+  9. _Reciprocal Properties of Direct and Reversed Motions._
+
+    Lagrange's formula.
+
+  We may employ Hamilton's principal function to prove a very remarkable
+  formula connecting any _two_ slightly disturbed natural motions of the
+  system. If we use the symbols [delta] and [Delta] to denote the
+  corresponding variations, the theorem is
+
+    d
+    --[Sigma]([delta]p_r.[Delta]q_r - [Delta]p_r.[delta]q_r) = 0;  (1)
+    dt
+
+  or integrating from t to t',
+
+    [Sigma]([delta]p'_r.[Delta]q'_r - [Delta]q'_r.[delta]q'_r) = [Sigma]([delta]p_r.[Delta]q_r - [Delta]p_r.[delta]q_r). (2)
+
+  If for shortness we write
+
+               dP squaredS                 dP squaredS
+    (r,s) = ----------, (r,s') = -----------,  (3)
+            dPq_rdPq_s           dPq_rdPq'_s
+
+  we have
+
+    dPp_r = - [Sigma]_s(r,s)[delta]q_s - [Sigma]_s(r,s')[delta]q'_s  (4)
+
+  with a similar expression for [Delta]p_r. Hence the right-hand side of
+  (2) becomes
+
+    - [Sigma]_r{[Sigma]_s(r,s)[delta]q_s + [Sigma]_s(r,s')[delta]q'_s}[Delta]q_r
+      + [Sigma]_r{[Sigma]_s(r,s)[Delta]q_s + [Sigma]_s(r,s')[Delta]q'_s}[delta]q_r
+        = [Sigma]_r[Sigma]_s(r,s'){[delta]q_r.[Delta]q'_s - [Delta]q_r.[delta]q'_s}. (5)
+
+  The same value is obtained in like manner for the expression on the
+  left hand of (2); hence the theorem, which, in the form (1), is due to
+  Lagrange, and was employed by him as the basis of his method of
+  treating the dynamical theory of _Variation of Arbitrary Constants_.
+
+
+    Helmholtz's reciprocal theorems.
+
+  The formula (2) leads at once to some remarkable reciprocal relations
+  which were first expressed, in their complete form, by Helmholtz.
+  Consider any natural motion of a conservative system between two
+  configurations O and O' through which it passes at times t and t'
+  respectively, and let t' - t = [tau]. As the system is passing through
+  O let a small impulse [delta]p_r be given to it, and let the
+  consequent alteration in the co-ordinate q_s after the time [tau] be
+  [delta]q'_s. Next consider the _reversed_ motion of the system, in
+  which it would, if undisturbed, pass from O' to O in the same time
+  [tau]. Let a small impulse [delta]p'_s be applied as the system is
+  passing through O', and let the consequent change in the co-ordinate
+  q_r after a time [tau] be [delta]q_r. Helmholtz's first theorem is to
+  the effect that
+
+    [delta]q_r : [delta]p'_s = [delta]q'_s : [delta]p_r.  (6)
+
+  To prove this, suppose, in (2), that all the [delta]q vanish, and
+  likewise all the [delta]p with the exception of [delta]p_r. Further,
+  suppose all the [Delta]q' to vanish, and likewise all the [Delta]p'
+  except [Delta]p'_s, the formula then gives
+
+    [delta]p_r.[Delta]q_r = - [Delta]p'_s.[delta]q'_s,  (7)
+
+  which is equivalent to Helmholtz's result, since we may suppose the
+  symbol [Delta] to refer to the reversed motion, provided we change
+  the signs of the [Delta]p. In the most general motion of a top
+  (MECHANICS, Sec. 22), suppose that a small impulsive couple about the
+  vertical produces after a time [tau] a change [delta][theta] in the
+  inclination of the axis, the theorem asserts that in the reversed
+  motion an equal impulsive couple in the plane of [theta] will produce
+  after a time [tau] a change [delta][psi], in the azimuth of the axis,
+  which is equal to [delta][theta]. It is understood, of course, that
+  the couples have no components (in the generalized sense) except of
+  the types indicated; for instance, they may consist in each case of a
+  force applied to the top at a point of the axis, and of the
+  accompanying reaction at the pivot. Again, in the corpuscular theory
+  of light let O, O' be any two points on the axis of a symmetrical
+  optical combination, and let V, V' be the corresponding velocities of
+  light. At O let a small impulse be applied perpendicular to the axis
+  so as to produce an angular deflection [delta][theta], and let ss'
+  be the corresponding lateral deviation at O'. In like manner in the
+  reversed motion, let a small deflection [delta][theta]' at O' produce
+  a lateral deviation ss at O. The theorem (6) asserts that
+
+            ss                  ss'
+    ----------------- = ---------------,  (8)
+    V'[delta][theta]'   V[delta][theta]
+
+  or, in optical language, the "apparent distance" of O from O' is to
+  that of O' from O in the ratio of the refractive indices at O' and O
+  respectively.
+
+
+    Helmholtz's second reciprocal theorem.
+
+  In the second reciprocal theorem of Helmholtz the configuration O is
+  slightly varied by a change [delta]q_r in one of the co-ordinates, the
+  momenta being all unaltered, and [delta]q'_s is the consequent
+  variation in one of the momenta after time [tau]. Similarly in the
+  reversed motion a change [delta]p'_s produces after time [tau] a
+  change of momentum [delta]p_r. The theorem asserts that
+
+    [delta]p'_s : [delta]q_r = [delta]p_r : [delta]q'_s  (9)
+
+  This follows at once from (2) if we imagine all the [delta]p to
+  vanish, and likewise all the [delta]q save [delta]q_r, and if
+  (further) we imagine all the [Delta]p' to vanish, and all the
+  [Delta]q' save [Delta]q'_s. Reverting to the optical illustration, if
+  F, F', be principal foci, we can infer that the convergence at F' of a
+  parallel beam from F is to the convergence at F of a parallel beam
+  from F' in the inverse ratio of the refractive indices at F' and F.
+  This is equivalent to Gauss's relation between the two principal focal
+  lengths of an optical instrument. It may be obtained otherwise as a
+  particular case of (8).
+
+  We have by no means exhausted the inferences to be drawn from
+  Lagrange's formula. It may be noted that (6) includes as particular
+  cases various important reciprocal relations in optics and acoustics
+  formulated by R.J.E. Clausius, Helmholtz, Thomson (Lord Kelvin) and
+  Tait, and Lord Rayleigh. In applying the theorem care must be taken
+  that in the reversed motion the reversal is complete, and extends to
+  every velocity in the system; in particular, in a cyclic system the
+  cyclic motions must be imagined to be reversed with the rest.
+  Conspicuous instances of the failure of the theorem through incomplete
+  reversal are afforded by the propagation of sound in a wind and the
+  propagation of light in a magnetic medium.
+
+  It may be worth while to point out, however, that there is no such
+  limitation to the use of Lagrange's formula (1). In applying it to
+  cyclic systems, it is convenient to introduce conditions already laid
+  down, viz. that the co-ordinates q_r are the palpable co-ordinates and
+  that the cyclic momenta are invariable. Special inference can then be
+  drawn as before, but the interpretation cannot be expressed so neatly
+  owing to the non-reversibility of the motion.
+
+  AUTHORITIES.--The most important and most accessible early authorities
+  are J.L. Lagrange, _Mecanique analytique_ (1st ed. Paris, 1788, 2nd
+  ed. Paris, 1811; reprinted in _Oeuvres_, vols. xi., xii., Paris,
+  1888-89); Hamilton, "On a General Method in Dynamics," _Phil. Trans._
+  1834 and 1835; C.G.J. Jacobi, _Vorlesungen ueber Dynamik_ (Berlin,
+  1866, reprinted in _Werke_, Supp.-Bd., Berlin, 1884). An account of
+  the extensive literature on the differential equations of dynamics and
+  on the theory of variation of parameters is given by A. Cayley,
+  "Report on Theoretical Dynamics," _Brit. Assn. Rep._ (1857),
+  _Mathematical Papers_, vol. iii. (Cambridge, 1890). For the modern
+  developments reference may be made to Thomson and Tait, _Natural
+  Philosophy_ (1st ed. Oxford, 1867, 2nd ed. Cambridge, 1879); Lord
+  Rayleigh, _Theory of Sound_, vol. i. (1st ed. London, 1877; 2nd ed.
+  London, 1894); E.J. Routh, _Stability of Motion_ (London, 1877), and
+  _Rigid Dynamics_ (4th ed. London, 1884); H. Helmholtz, "Ueber die
+  physikalische Bedeutung des Prinzips der kleinsten Action," _Crelle_,
+  vol. c., 1886, reprinted (with other cognate papers) in _Wiss. Abh._
+  vol. iii. (Leipzig, 1895); J. Larmor, "On Least Action," _Proc. Lond.
+  Math. Soc._ vol. xv. (1884); E.T. Whittaker, _Analytical Dynamics_
+  (Cambridge, 1904). As to the question of stability, reference may be
+  made to H. Poincare, "Sur l'equilibre d'une masse fluide animee d'un
+  mouvement de rotation" _Acta math._ vol. vii. (1885); F. Klein and A.
+  Sommerfeld, _Theorie des Kreisels_, pts. 1, 2 (Leipzig, 1897-1898); A.
+  Lioupanoff and J. Hadamard, _Liouville_, 5me serie, vol. iii. (1897);
+  T.J.I. Bromwich, Proc. Lond. Math. Soc. vol. xxxiii. (1901). A
+  remarkable interpretation of various dynamical principles is given by
+  H. Hertz in his posthumous work _Die Prinzipien der Mechanik_
+  (Leipzig, 1894), of which an English translation appeared in 1900.
+       (H. Lb.)
+
+
+
+
+DYNAMITE (Gr. [Greek: dynamis], power), the name given to several
+explosive preparations containing nitroglycerin (q.v.) which are almost
+exclusively used for blasting purposes. The first practical application
+of nitroglycerin in this way was made by A. Nobel in 1863. He soaked
+gunpowder with the liquid and fired the gunpowder by an ordinary fuse.
+Later he found that nitroglycerin could be detonated by the explosion of
+several materials such as fulminate of mercury, the use of which as a
+detonator he patented in 1867. In 1866-1867 he experimented with
+charcoal and other substances, and found the infusorial earth known as
+kieselguhr, which consists mainly of silica (nearly 95%), eminently
+adapted to the purpose, as it was inert, non-combustible, and after a
+little heating and preparation very porous, retaining a large amount of
+nitroglycerin as water is held in a sponge, without very serious
+exudation on standing. This kieselguhr dynamite is generally made by
+incorporating three parts of nitroglycerin with one part of the dry
+earth, the paste being then formed into cylindrical cartridges. This
+work is done by hand. Generally a small percentage of the kieselguhr is
+replaced by a mixture containing sodium and ammonium carbonates, talc
+and ochre. This product is known as dynamite No. 1. Disabilities
+attaching to kieselguhr dynamite are that when placed in water the
+nitroglycerin is liable to be exuded or displaced, also that, like
+nitroglycerin itself, it freezes fairly easily and thawing the frozen
+cartridges is a dangerous operation. Other substances, e.g. kaolin,
+tripoli, magnesia alba (magnesium carbonate), alumina, sugar, charcoal,
+some powdered salts and mixtures of sawdust and salts, have been shown
+to be absorbents more or less adapted to the purpose of making a
+dynamite. Charcoal from cork is said to absorb about 90% of its weight
+of nitroglycerin. With the idea of obtaining greater safety, mixtures
+have been made of nitroglycerin with wood fibre, charcoal and metallic
+nitrates. Lithofracteur, for instance, consists of 50% nitroglycerin and
+a mixture of prepared sawdust, kieselguhr and barium nitrate. Carbonite
+contains 25% of nitroglycerin, the remainder being a mixture of
+wood-meal and alkali nitrates, with about 1% of sulphur. Dualin, atlas
+dynamite and potentite are other modifications.
+
+A convenient form in which nitroglycerin can be made up for blasting
+purposes, especially in wet ground, is the gelatinous material obtained
+by the action of nitroglycerin, either alone or with the help of
+solvents, on low-grade or soluble gun-cottons. It is known as blasting
+gelatin, and was first made by Nobel by incorporating 6 or 7% of low
+nitrated cellulose (collodion cotton or soluble gun-cotton) with
+slightly warmed nitroglycerin. The result is a transparent plastic
+material, of specific gravity 1.5 to 1.6, which may be kept under water
+for a long time without appreciable change. It is less sensitive to
+detonation than ordinary dynamite, and although its explosion is
+slightly slower it is more powerful than dynamite and much superior to
+the liquid nitroglycerin. Blasting gelatin also freezes and is sensitive
+to percussion in this state. Camphor and other substances have been
+added to blasting gelatin to render it more solid and less sensitive.
+Some modifications of blasting gelatin, e.g. gelignite, contain
+wood-meal and such oxygen-containing salts as potassium nitrate.
+Experience has conclusively shown that dynamites are more satisfactory,
+quicker, and more intense in action than liquid nitroglycerin.
+
+To prevent nitroglycerin and some of the forms of dynamite from freezing
+it has been proposed to add to them small quantities of either
+monochlor-dinitroglycerin or of a nitrated poly-glycerin. The former is
+obtained by first acting upon glycerin with hydrogen chloride to produce
+_u-_chlorhydrin or chlor-propylene glycol, C3H7O2Cl, which is then
+nitrated as in the case of glycerin. The latter is obtained by heating
+glycerin for six or seven hours to about 300 deg. C., whereby water is split
+off in such manner that a diglycerin C6H14O5, for the most part,
+results. This on nitration in the usual manner gives a product
+C6H{10}N4O{13}, which burns and explodes in a similar manner to ordinary
+nitroglycerin, but is less sensitive and does not so easily freeze. The
+mono- and di-nitrates of glycerin have also been proposed as additions
+to ordinary nitroglycerin (q.v.) for the same purpose.     (W. R. E. H.)
+
+
+
+
+DYNAMO (a shortened form of "dynamo-electric machine," from Gr. [Greek:
+dynamis], power), a machine for converting mechanical into electrical
+energy.
+
+The dynamo ranks with the telegraph and telephone as one of the three
+striking applications of electrical and magnetic science to which the
+material progress that marked the second half of the 19th century was in
+no small measure due. Since the discovery of the principle of the dynamo
+by Faraday in 1831 the simple model which he first constructed has been
+gradually developed into the machines of 5000 horse-power or more which
+are now built to meet the needs of large cities for electric lighting
+and power, while at the same time the numbers of dynamos in use have
+increased almost beyond estimate. Yet such was the insight of Faraday
+into the fundamental nature of the dynamo that the theory of its action
+which he laid down has remained essentially unchanged. His experiments
+on the current which was set up in a coil of wire during its movement
+across the poles of a magnet led naturally to the explanation of induced
+electromotive force as caused by the linking or unlinking of magnetic
+lines of flux with an electric circuit. For the more definite case of
+the dynamo, however, we may, with Faraday, make the transition from
+line-linkage to the equivalent conception of "line-cutting" as the
+source of E.M.F.--in other words, to the idea of electric conductors
+"cutting" or intersecting[1] the lines of flux in virtue of relative
+motion of the magnetic field and electric circuit. On the 28th of
+October 1831 Faraday mounted a copper disk so that it could be rotated
+edgewise between the poles of a permanent horse-shoe magnet. When so
+rotated, it cut the lines of flux which passed transversely through its
+lower half, and by means of two rubbing contacts, one on its periphery
+and the other on its spindle, the circuit was closed through a
+galvanometer, which indicated the passage of a continuous current so
+long as the disk was rotated (fig. 1). Thus by the invention of the
+first dynamo Faraday proved his idea that the E.M.F. induced through the
+interaction of a magnetic field and an electric circuit was due to the
+passage of a portion of the electric circuit _across_ the lines of flux,
+or vice versa, and so could be maintained if the cutting of the lines
+were made continuous.[2] In comparison with Faraday's results, the
+subsequent advance is to be regarded as a progressive perfecting of the
+mechanical and electro-magnetic design, partly from the theoretical and
+partly from the practical side, rather than as modifying or adding to
+the idea which was originally present in his mind, and of which he
+already saw the possibilities.
+
+[Illustration: FIG. 1.]
+
+A dynamo, then, is a machine in which, by means of continuous relative
+motion, an electrical conductor or system of conductors forming part of
+a circuit is caused to cut the lines of a magnetic field or fields; the
+cutting of the magnetic flux induces an electromotive force in the
+conductors, and when the circuit is closed a current flows, whereby
+mechanical energy is converted into electrical energy.
+
+  Little practical use could be made of electrical energy so long as its
+  only known sources were frictional machines and voltaic batteries. The
+  cost of the materials for producing electrical currents on a large
+  scale by chemical action was prohibitive, while the frictional machine
+  only yielded very small currents at extremely high potentials. In the
+  dynamo, on the other hand, electrical energy in a convenient form
+  could be cheaply and easily obtained by mechanical means, and with its
+  invention the application of electricity to a wide range of commercial
+  purposes became economically possible. As a converter of energy from
+  one form to another it is only surpassed in efficiency by another
+  electrical appliance, namely, the transformer (see TRANSFORMERS). In
+  this there is merely conversion of electrical energy at a high
+  potential into electrical energy at a low potential, or vice versa,
+  but in the dynamo the mechanical energy which must be applied to
+  maintain the relative movement of magnetic field and conductor is
+  absorbed, and reappears in an electrical form. A true transformation
+  takes place, and the proportion which the rate of delivery of
+  electrical energy bears to the power absorbed, or in other words the
+  _efficiency_, is the more remarkable. The useful return or "output" at
+  the terminals of a large machine may amount to as much as 95% of the
+  mechanical energy which forms the "input." Since it needs some prime
+  mover to drive it, the dynamo has not made any direct addition to our
+  sources of energy, and does not therefore rank with the primary
+  battery or oil-engine, or even the steam-engine, all of which draw
+  their energy more immediately from nature. Yet by the aid of the
+  dynamo the power to be derived from waterfalls can be economically and
+  conveniently converted into an electrical form and brought to the
+  neighbouring factory or distant town, to be there reconverted by
+  motors into mechanical power. Over any but very short distances energy
+  is most easily transmitted when it is in an electrical form, and
+  turbine-driven dynamos are very largely and successfully employed for
+  such transmission. Thus by conducing to the utilization of water-power
+  which may previously have had but little value owing to its
+  disadvantageous situation, the dynamo may almost be said to have added
+  another to our available natural resources.
+
+The two essential parts of the dynamo, as required by its definition,
+may be illustrated by the original disk machine of Faraday. They are (1)
+the _iron magnet_, between the poles of which a magnetic field exists,
+and (2) the _electrical conductors_, represented by the rotating copper
+disk. The sector of the disk cutting the lines of the field forms part
+of a closed electric circuit, and has an E.M.F. induced in it, by reason
+of which it is no longer simply a conductor, but has become "active." In
+its more highly developed form the simple copper disk is elaborated into
+a system of many active wires or bars which form the "winding," and
+which are so interconnected as to add up their several E.M.F.'s. Since
+these active wires are usually mounted on an iron structure, which may
+be likened to the keeper or "armature" of a magnet rotating between its
+poles, the term "armature" has been extended to cover not only the iron
+core, but also the wires on it, and when there is no iron core it is
+even applied to the copper conductors themselves. In the dynamo of
+Faraday the "armature" was the rotating portion, and such is the case
+with modern continuous-current dynamos; in alternators, however, the
+magnet, or a portion of it, is more commonly rotated while the armature
+is stationary. It is in fact immaterial to the action whether the one or
+the other is moved, or both, so long as their relative motion causes the
+armature conductors to cut the magnetic flux. As to the ultimate reason
+why an E.M.F. should be thereby induced, physical science cannot as yet
+yield any surer knowledge than in the days of Faraday.[3] For the
+engineer, it suffices to know that the E.M.F. of the dynamo is due to
+the cutting of the magnetic flux by the active wires, and, further, is
+proportional to the rate at which the lines are cut.[4]
+
+[Illustration: FIG. 2.]
+
+The equation of the _electromotive force_ which is required in order to
+render this statement quantitative must contain three factors, namely,
+the density of the flux in the air-gap through which the armature
+conductors move, the active length of these wires, and the speed of
+their movement. For given values of the first and third factors and a
+single straight wire moved parallel to itself through a uniform field,
+the maximum rate of cutting is evidently obtained when the three
+directions of the lines of the conductor's length and of the relative
+motion are respectively at right angles to each other, as shown by the
+three co-ordinate axes of fig. 2. The E.M.F. of the single wire is then
+
+  E = B_gLV x 10^(-8) volts  (1)
+
+where B_g is the density of the flux within the air-gap expressed in
+C.G.S. lines per square centimetre, L is the active length of the
+conductor within the field in centimetres, and V is the velocity of
+movement in centimetres per second. Further, the direction in which the
+E.M.F. has the above maximum value is along the length of the conductor,
+its "sense" being determined by the direction of the movement[5] in
+relation to the direction of the field.
+
+The second fundamental equation of the dynamo brings to light its
+mechanical side, and rests on H.C. Oersted's discovery of the
+interaction of a magnetic field and an electric current. If a straight
+electric conductor through which a current is passing be so placed in a
+magnetic field that its length is not parallel to the direction of the
+lines of flux, it is acted on by a force which will move it, if free, in
+a definite direction relatively to the magnet; or if the conductor is
+fixed and the magnet is free, the latter will itself move in the
+opposite direction. Now in the dynamo the active wires are placed so
+that their length is at right angles to the field; hence when they are
+rotated and an electric current begins to flow under the E.M.F. which
+they induce, a mutual force at once arises between the copper conductors
+and the magnet, and the direction of this force must by Lenz's law be
+opposed to the direction of the movement. Thus as soon as the disk of
+fig. 1 is rotated and its circuit is closed, it experiences a mechanical
+pull or drag which must be overcome by the force applied to turn the
+disk. While the magnet must be firmly held so as to remain stationary,
+the armature must be of such mechanical construction that its wires can
+be forcibly driven through the magnetic field against the mutual pull.
+This law of electrodynamic action may be quantitatively stated in an
+_equation of mechanical force_, analogous to the equation (I.) of
+electromotive force, which states the law of electromagnetic induction.
+If a conductor of length L cm., carrying a current C amperes, is
+immersed in a field of uniform density B_g, and the length of the
+conductor is at right angles to the direction of the lines, it is acted
+on by a force
+
+  F = B_gLC x 10^(-1) dynes,  (2)
+
+and the direction of this force is at right angles to the conductor and
+to the field. The rate at which electrical energy is developed, when
+this force is overcome by moving the conductor as a dynamo through the
+field, is EC = B_gLVC x 10^(-8) watts, whence the equality of the
+mechanical power absorbed and the electrical power developed (as
+required by the law of the conservation of energy) is easily
+established. The whole of this power is not, however, available at the
+terminals of the machine; if R_a be the resistance of the armature in
+ohms, the passage of the current C_a through the armature conductors
+causes a drop of pressure of C_aR_a volts, and a corresponding loss of
+energy in the armature at the rate of C_a squaredR_a watts. As the resistance
+of the external circuit R_e is lowered, the current C = E_a/(R_e + R_a)
+is increased. The increase of the current is, however, accompanied by a
+progressive increase in the loss of energy over the armature, and as
+this is expended in heating the armature conductors, their temperature
+may rise so much as to destroy the insulating materials with which they
+are covered. Hence the temperature which the machine may be permitted to
+attain in its working is of great importance in determining its output,
+the current which forms one factor therein being primarily limited by
+the heating which it produces in the armature winding. The lower the
+resistance of the armature, the less the rise of its temperature for a
+given current flowing through it; and the reason for the almost
+universal adoption of copper as the material for the armature conductors
+is now seen to lie in its high conductivity.[6]
+
+Since the voltage of the dynamo is the second factor to which its output
+is proportional, the conditions which render the induced E.M.F. a
+maximum must evidently be reproduced as far as possible in practice, if
+the best use is to be made of a given mass of iron and copper. The first
+problem, therefore, in the construction of the dynamo is the disposition
+of the wires and field in such a manner that the three directions of
+field, length of active conductors, and movement are at right angles to
+one another, and so that the relative motion is continuous.
+Reciprocating motion, such as would be obtained by direct attachment of
+the conductors to the piston of a steam-engine, has been successfully
+employed only in the special case of an "oscillator,"[7] producing a
+small current very rapidly changing in direction. Rotary motion is
+therefore universally adopted, and with this two distinct cases arise.
+Either (A) the active length of the wire is parallel to the axis of
+rotation, or (B) it is at right angles to it.
+
+[Illustration: FIG. 3.]
+
+(A) If a conductor is rotated in the gap between the poles of a
+horse-shoe magnet, and these poles have plane parallel faces opposing
+one another as in fig. 3, not only is the density of the flux in the
+interpolar gap small, but the direction of movement is not always at
+right angles to the direction of the lines, which for the most part pass
+straight across from one opposing face to the other. When the conductor
+is midway between the poles (i.e. either at its highest or lowest
+point), it is at this instant sliding along the lines and does not cut
+them, so that its E.M.F. is zero. Taking this position as the
+starting-point, as the conductor moves round, its rate of line-cutting
+increases to a maximum when it has moved through a right angle and is
+opposite to the centre of a pole-face (as in fig. 3), from which point
+onward the rate decreases to zero when it has moved through 180 deg.. Each
+time the conductor crosses a line drawn symmetrically through the gap
+between the poles and at right angles to the axis of rotation, the
+E.M.F. along its length is reversed in direction, since the motion
+relatively to the direction of the field is reversed. If the ends of the
+active conductor are electrically connected to two collecting rings
+fixed upon, but insulated from, the shaft, two stationary brushes bb can
+be pressed on the rings so as to make a sliding contact. An external
+circuit can then be connected to the brushes, which will form the
+"terminals" of the machine, the periodically reversed or alternating
+E.M.F. induced in the active conductor will cause an alternating current
+to flow through conductor and external circuit, and the simplest form of
+"alternator" is obtained. If the field cut by the straight conductor is
+of uniform density, and all the lines pass straight across from one
+pole-face to the other (both of which assumptions are approximately
+correct), a curve connecting the instantaneous values of the E.M.F. as
+ordinates with time or degrees of angular movement as abscissae (as
+shown at the foot of fig. 3), will, if the speed of rotation be uniform,
+be a sine curve. If, however, the conductor is mounted on an iron
+cylinder (fig. 4),[8] a sufficient margin being allowed for mechanical
+clearance between it and the poles, not only will the reluctance of the
+magnetic circuit be reduced and the total flux and its density in the
+air-gap B_g be thereby increased, but the path of the lines will become
+nearly radial, except at the "fringe" near the edges of the pole-tips;
+hence the relative directions of the movement and of the lines will be
+continuously at right angles. The shape of the E.M.F. curve will then be
+as shown in fig. 4--flat-topped, with rounded corners rapidly sloping
+down to the zero line.
+
+[Illustration: FIG. 4.]
+
+But a single wire cannot thus be made to give more than a few volts, and
+while dynamos for voltages from 5 to 10 are required for certain
+purposes, the voltages in common use range from 100 to 10,000. It is
+therefore necessary to connect a number of such wires in series, so as
+to form an "armature winding." If several similar conductors are
+arranged along the length of the iron core parallel to the first (fig.
+5), the E.M.F.'s generated in the conductors which at any moment are
+under the same pole are similarly directed, and are opposite to the
+directions of the E.M.F.'s in the conductors under the other pole (cf
+fig. 5 where the dotted and crossed ends of the wires indicate E.M.F.'s
+directed respectively towards and away from the observer). Two distinct
+methods of winding thence arise, the similarity of the E.M.F.'s under
+the same pole being taken advantage of in the first, and the opposite
+E.M.F.'s under N and S poles in the second.
+
+[Illustration: FIG. 5.]
+
+[Illustration: FIG. 6.]
+
+1. The first, or _ring_-winding, was invented by Dr Antonio Pacinotti of
+Florence[9] in 1860, and was subsequently and independently reintroduced
+in 1870[10] by the Belgian electrician, Zenobe Theophile Gramme, whence
+it is also frequently called the "Gramme" winding. By this method the
+farther end of conductor 1 (fig. 5) is joined in series to the near end
+of conductor 2; this latter lies next to it on the surface of the core
+or immediately above it, so that both are simultaneously under the same
+pole-piece. For this series connexion to be possible, the armature core
+must be a hollow cylinder, supported from the shaft on an open
+non-magnetic spider or hub, between the arms of which there is room for
+the internal wire completing the loop (fig. 6). The end of one complete
+loop or turn embracing one side of the armature core thus forms the
+starting-point for another loop, and the process can be continued if
+required to form a coil of two or more turns. In the ring armature the
+iron core serves the double purpose of conducting the lines across from
+one pole to the other, and also of shielding from the magnetic flux the
+hollow interior through which the connecting wires pass. Any lines which
+leak across the central space are cut by the internal wires, and the
+direction of cutting is such that the E.M.F. caused thereby opposes the
+E.M.F. due to the active conductors proper on the external surface. If,
+however, the section of iron in the core be correctly proportioned, the
+number of lines which cross the interior will bear but a small ratio to
+those which pass entirely through the iron, and the counter E.M.F. of
+the internal wires will become very small; they may then be regarded
+simply as connectors for joining the external active wires in series.
+
+[Illustration: FIG. 7.]
+
+2. The second or _drum_ method was used in the original "shuttle-wound"
+armatures invented by Dr Werner von Siemens in 1856, and is sometimes
+called the "Siemens" winding. The farther end of conductor 1 (fig. 5) is
+joined by a connecting wire to the farther end of another conductor 2'
+situated nearly diametrically opposite on the other side of the core and
+under the opposite pole-piece. The near end of the complete loop or turn
+is then brought across the end of the core, and can be used as the
+starting-point for another loop beginning with conductor 2, which is
+situated by the side of the first conductor. The iron core may now be
+solid from the surface to the shaft, since no connecting wires are
+brought through the centre, and each loop embraces the entire armature
+core (fig. 7). By the formation of two loops in the ring armature and of
+the single loop in the drum armature, two active wires are placed in
+series; the curves of instantaneous E.M.F. are therefore similar in
+shape to that of the single wire (fig. 4), but with their ordinates
+raised throughout to double their former height, as shown at the foot of
+fig. 6.
+
+Next, if the free ends of either the ring or drum loops, instead of
+being connected to two collecting rings, are attached to the two halves
+of a split-ring insulated from the shaft (as shown in fig. 7 in
+connexion with a drum armature), and the stationary brushes are so set
+relatively to the loops that they pass over from the one half of the
+split-ring to the other half at the moment when the loops are passing
+the centre of the interpolar gap, and so are giving little or no E.M.F.,
+each brush will always remain either positive or negative. The current
+in the external circuit attached to the brushes will then have a
+constant direction, although the E.M.F. in the active wires still
+remains alternating; the curve of E.M.F. obtained at the brushes is thus
+(as in fig. 7) entirely above the zero line. The first dynamo of H.
+Pixii,[11] which immediately followed Faraday's discovery, gave an
+alternating current, but in 1832[12] the alternator was converted into a
+machine giving a _unidirected current_ by the substitution of a
+rudimentary "commutator" in place of mercury collecting cups.
+
+(B) So far the length of the active wires has been parallel to the axis
+of rotation, but they may equally well be arranged perpendicularly
+thereto. The poles will then have plane faces and the active wires will
+be disposed with their length approximately radial to the axis of the
+shaft. In order to add their E.M.F.'s in series, two types of winding
+may be employed, which are precisely analogous in principle to the ring
+and drum windings under arrangement (A).
+
+3. The _discoidal_ or flat-ring armature is equivalent to a ring of
+which the radial depth greatly exceeds the length, with the poles
+presented to one side of the ring instead of embracing its cylindrical
+surface. A similar set of poles is also presented to the opposite side
+of the ring, like poles being opposite to one another, so that in effect
+each polar surface is divided into two halves, and the groups of lines
+from each side bifurcate and pass circumferentially through the armature
+core to issue into the adjacent poles of opposite sign.
+
+4. In the _disk_ machine, no iron core is necessary for the armature,
+the two opposite poles of unlike sign being brought close together,
+leaving but a short path for the lines in the air-gap through which the
+active wires are rotated.
+
+If the above elementary dynamos are compared with fig. 1, it will be
+found that they all possess a distinctive feature which is not present
+in the original disk machine of Faraday. In the four types of machine
+above described each active wire in each revolution first cuts the group
+of lines forming a field in one direction, and then cuts the same lines
+again in the opposite direction relatively to the sense of the lines, so
+that along the length of the wire the E.M.F. alternates in direction.
+But in the dynamo of fig. 1 the sector of the copper disk which is at
+any moment moving through the magnetic field and which forms the single
+active element is always cutting the lines in the same manner, so that
+the E.M.F. generated along its radial length is continuous and unchanged
+in direction. This radical distinction differentiates the two classes of
+_heteropolar_ and _homopolar_ dynamos, Faraday's disk machine of fig. 1
+being the type of the latter class. In it the active element may be
+arranged either parallel or at right angles to the axis of rotation;
+but in both cases, in order to increase the E.M.F. by placing two or
+more elements in series, it becomes necessary either (1) to employ some
+form of sliding contact by which the current may be collected from the
+end of one active element and passed round a connecting wire into the
+next element without again cutting the field in the reverse direction,
+or (2) to form on the armature a loop of which each side is alternately
+active and inactive. The first method limits the possibilities of the
+homopolar machine so greatly when large currents and high voltages are
+required that it is now only used in rare instances, as e.g.
+occasionally in dynamos driven by steam-turbines which have a very high
+speed of rotation. The second alternative may be carried into effect
+with any of the four methods of armature winding, but is practically
+confined to the drum and disk types. In its drum form the field is
+divided into two or more projecting poles, all of the same sign, with
+intervening neutral spaces of equal width, and the span of the loop in
+the direction of rotation is at least equal to the width of a polar
+projection, as in fig. 8, where two polar projections are shown. Each
+side of the loop then plays a dual part; it first cuts the lines of one
+polar projection and generates an E.M.F., and next becomes an inactive
+connecting wire, while the action is taken up by the opposite side of
+the loop which has previously served as a connector but now cuts the
+lines of the next polar projection. The E.M.F. is thus always in the
+same direction along the side which is at any moment active, but
+alternates round the loop as a whole, and the distinctive peculiarity of
+the homopolar machine, so soon as any form of "winding" is introduced
+into its armature, is lost. It results that the homopolar principle,
+which would prima facie appear specially suitable for the generation of
+a unidirectional E.M.F. and continuous current, can seldom be used for
+this purpose and is practically confined to alternators. It may
+therefore be said that in almost all dynamos, whether they supply an
+alternating or a continuous current in the external circuit, the E.M.F.
+and current in the armature are alternating.
+
+[Illustration: FIG. 8.]
+
+Ring winding was largely employed in early continuous-current dynamos
+and also in the alternators of Gramme and H. Wilde, and later of Auguste
+de Meritens. Disk winding was also successfully introduced for
+alternators, as in the magneto-machines of Nollet (1849) and the
+alternators of Wilde (1866) and Siemens (1878), and its use was
+continued in the machines of W.M. Mordey and S.Z. Ferranti. But although
+the ring, discoidal-ring and disk methods of winding deserve mention
+from their historical importance, experience has shown that drum winding
+possesses a marked superiority for both electrical and manufacturing
+reasons; the three former methods have in fact been practically
+discarded in its favour, so that the drum method will hereafter alone be
+considered.
+
+The drum coil, composed of several loops wound side by side, may
+therefore be regarded as the constituent active element out of which the
+armature winding of the modern dynamo is developed. Its application to
+the multipolar machine is easily followed from fig. 9, which illustrates
+the heteropolar type of dynamo. The span of the loops, which is nearly
+180 deg. or across the diameter of the two-pole machine, is reduced
+approximately to 90 deg. in the four-pole or to 60 deg. in the six-pole machine
+and so on, the curvature of the coil becoming gradually less as the
+number of poles is increased. The passage of a coil through two magnetic
+fields of opposite direction yields a complete wave of E.M.F., such as
+is shown in fig. 6, and the time in seconds taken to pass through such a
+complete cycle is the "period" of the alternating E.M.F. The number of
+complete periods through which the E.M.F. of the coil passes per second
+is called the "periodicity" or "frequency" of the machine. In the
+bipolar machine this is equal to the number of revolutions per second,
+and in the multipolar machine it is equal to the number of pairs of
+fields through which the coil passes in one second; hence in general the
+periodicity is pN/60, where N = the number of revolutions per minute and
+p = the number of pairs of poles, and this holds true of the E.M.F. and
+current round the coil, even though the E.M.F. and current furnished to
+the external circuit may be rendered unidirectional or continuous. The
+only difference on this point is that in the continuous-current machine
+the poles are usually fewer than in the alternator, and the periodicity
+is correspondingly lower. Thus in the former case the number of poles
+ranges from 2 to 12 and the usual frequencies from 5 to 20; but with
+alternators the frequencies in commercial use range from 25 to 120, and
+in large machines driven by slow-speed engines the number of poles may
+even be as high as 96.
+
+[Illustration: FIG. 9.
+
+I. Smooth. II. Toothed.]
+
+[Illustration: FIG. 10.]
+
+The drum coil may be applied either to the external surface of a
+rotating armature, the field-magnet being external and stationary (fig.
+9), or to the internal surface of a stationary armature (fig. 10), the
+field-magnet being internal and rotating. While the former combination
+is universally adopted in the continuous-current dynamo, the latter is
+more usual in the modern alternator. In either case the iron armature
+core must be "laminated"; the passage of the lines of the field across
+its surface sets up E.M.F.'s which are in opposite directions under
+poles of opposite sign, so that if the core were a solid mass a
+current-sheet would flow along its surface opposite to a pole, and
+complete its circuit by passing through the deeper layers of metal or by
+returning in a sheet under a pole of opposite sign. Such "eddy-currents"
+can be practically avoided by dividing the metal core into laminations
+at right angles to the length of the active wires which are themselves
+arranged to secure the greatest rate of line-cutting and maximum E.M.F.
+The production of the eddy-current E.M.F. is not thereby prevented, but
+the paths of the eddy-currents are so broken up that the comparatively
+high resistance with which they meet reduces their amount very greatly.
+The laminae must be lightly insulated from one another, right up to
+their edges, so that the E.M.F.'s which still act across their thickness
+will not be added up along the length of the core, but will only produce
+extremely small currents circulating through the interior of the
+separate laminations. Each thin iron plate is either coated with an
+insulating varnish or has one of its sides covered with a sheet of very
+thin paper; the thickness of the laminae is usually about one-fortieth
+of an inch, and if this is not exceeded the rate at which energy is
+dissipated by eddy-currents in the core is so far reduced that it does
+not seriously impair the efficiency of the machine.
+
+Lastly, the drum coils may be either attached to the surface of a smooth
+armature core (fig. 9, I.), or may be wound through holes formed close
+to the periphery of the core, or may be embedded in the slots between
+projecting iron teeth (figs. 9 [II.] and 10). Originally employed by
+Antonio Pacinotti in connexion with ring winding, the toothed armature
+was after some considerable use largely discarded in favour of the
+smooth core; it has, however, been reintroduced with a fuller
+understanding of the special precautions necessitated in its design, and
+it is now so commonly used that it may be said to have superseded the
+smooth-surface armature.
+
+  Not only does the toothed armature reduce the length of the air-gap to
+  the minimum permitted by mechanical and magnetic considerations, and
+  furnish better mechanical protection to the armature coils, but it
+  also ensures the positive holding of the active wires against the
+  mechanical drag which they experience as they pass through the
+  magnetic field. Further, the active wires in the toothed armature are
+  relieved of a large proportion of this mechanical drag, which is
+  transferred to the iron teeth. The lines of the field, after passing
+  through the air-gap proper, divide between the teeth and the slots in
+  proportion to their relative permeances. Hence at any moment the
+  active wires are situated in a weak field, and for a given armature
+  current the force on them is only proportional to this weak field.
+  This important result is connected with the fact that when the
+  armature is giving current the distribution of the lines over the face
+  of each tooth is distorted, so that they become denser on the
+  "trailing" side than on the "leading" side;[13] the effect of the
+  non-uniform distribution acting on all the teeth is to produce a
+  magnetic drag on the armature core proportional to the current passing
+  through the wires, so that the total resisting force remains the same
+  as if the armature had a smooth core. The amount by which the stress
+  on the active wires is reduced entirely depends upon the degree to
+  which the teeth are saturated, but, since the relative permeability of
+  iron even at a flux density of 20,000 lines per sq. cm. is to that of
+  air approximately as 33:1, the embedded wires are very largely
+  relieved of the driving stress. An additional gain is that solid bars
+  of much greater width can be used in the toothed armature than on a
+  smooth core without appreciable loss from eddy-currents within their
+  mass.
+
+  A disadvantage of the slotted core is, however, that it usually
+  necessitates the lamination of the pole-pieces. If the top of the slot
+  is open, and its width of opening is considerably greater than the
+  length of the air-gap from the iron of the pole-face to the surface of
+  the teeth, the lines become unequally distributed not only at the
+  surface of the teeth, but also at the face of the pole-pieces; and
+  this massing of the lines into bands causes the density at the
+  pole-face to be rhythmically varied as the teeth pass under it. No
+  such variation can take place in a solid mass of metal without the
+  production of eddy-currents within it; hence if the width of the
+  slot-opening is equal to or exceeds twice the length of the single
+  air-gap, lamination of the pole-pieces in the same plane as that of
+  the armature core becomes advisable.
+
+  If the wires are threaded through holes or tunnels pierced close to
+  the periphery of the core, the same advantages are gained as with open
+  slots, and lamination of the pole-pieces is rendered unnecessary. But
+  on the other hand, the process of winding becomes laborious and
+  expensive, while the increase in the inductance of the coils owing to
+  their being surrounded by a closed iron circuit is prejudicial to
+  sparkless commutation in the continuous-current dynamo and to the
+  regulation of the voltage of the alternator. A compromise is found in
+  the half-closed slot, which is not uncommon in alternators, although
+  the open slot is more usual in continuous-current dynamos.
+
+With the addition of more turns to the elementary drum loop or of
+several complete coils, new questions arise, and in connexion therewith
+the two great classes of machines, viz. alternators and
+continuous-current dynamos, which have above been treated side by side,
+diverge considerably, so that they are best considered separately. The
+electromotive-force equation of the alternator will be first deduced,
+and subsequently that of the continuous-current machine.
+
+[Illustration: FIG. 11.]
+
+Corresponding to the number of pairs of poles in the multipolar
+alternator, it is evident that there may also be an equal number of
+coils as shown diagrammatically in fig. 11. The additional coils, being
+similarly situated in respect to other pairs of poles, will exactly
+reproduce the E.M.F. of the original coil in phase and magnitude, so
+that when they are connected in series the total E.M.F. will be
+proportional to the number of coils in series; or if they are connected
+in parallel, while not adding to the E.M.F., they will proportionately
+increase the current-carrying capacity of the combination. But within
+each coil the addition of more loops will not cause an equal increase in
+the total E.M.F., unless the phases of the component E.M.F.'s due to the
+several turns are identical, and on this account it becomes necessary to
+consider the effect of the width of the coil-side.
+
+[Illustration: FIG. 12.]
+
+If the additional loops are wound within the same slots as the original
+loop, the winding is "concentrated," and each turn will then add the
+same E.M.F. But if the coil-side is divided between two or more slots,
+the phase of the E.M.F. yielded by the wires in one slot being different
+from that of the wires in another neighbouring slot, the sum of all the
+E.M.F.'s will be less than the E.M.F. of one component loop multiplied
+by the number of loops or turns in the coil. The percentage reduction in
+the E.M.F. will depend upon the number of the slots in a coil-side and
+their distance apart, i.e. on the virtual width of the coil-side
+expressed as a fraction of the "pole-pitch" or the distance measured
+along the pitch-line from the centre of one pole to the centre of a
+neighbouring pole of opposite sign (fig. 12). The winding is now to be
+regarded as "grouped," since a small number of distinct phases
+corresponding to the groups within the two, three or four slots have to
+be compounded together. As the number of slots per coil-side is
+increased, an approach is gradually made to the case of "uniform
+distribution," such as would obtain in a smooth-core armature in which
+the turns of the coil are wound closely side by side. Thus in the
+six-turn coil of fig. 12 A, which represents the development of a
+two-pole armature when the core is cut down to the shaft and opened out
+flat, there are in effect six phases compounded together, each of which
+differs but little from that of its next neighbour. With numerous wires
+lying still closer together a large number of phases are compounded
+until the distribution becomes practically uniform; the decrease in the
+E.M.F., as compared with that of a single turn multiplied by the number
+in series, is then immediately dependent upon the width of the coil-side
+relatively to the pole-pitch.
+
+[Illustration: FIG. 13.]
+
+If the width of the inner loop of fig. 12 A is less than that of the
+pole-face, its two sides will for some portion of each period be moving
+under the same pole, and "differential action" results, the net E.M.F.
+being only that due to the difference between the E.M.F.'s of the two
+sides. The loop of smallest width must therefore exceed the width of
+pole-face, if direct differential action is to be avoided. The same
+consideration also determines the width of the outer loop; if this be
+deducted from twice the pole-pitch, the difference should not be less
+than the width of the pole-face, so that, e.g., in a bipolar machine the
+outer loop may stand to the S. pole exactly as the inner loop stands to
+the N. pole (fig. 13). In other words, the width of the coil-side must
+not exceed the width of the interpolar gap between two fields. Evidently
+then if the ratio of the pole-width to the pole-pitch approaches unity,
+the width of the coil-side must be very small, and vice versa. A
+compromise between these conflicting considerations is found if the pole
+is made not much more than half the pole-pitch, and the width of the
+coil-side is similarly about half the pole-pitch and therefore equal in
+width to the pole (fig. 13). A single large coil, such as that of fig.
+12 A, can, however, equally well be divided into two halves by taking
+the end-connexions of one half of the turns round the opposite side of
+the shaft (fig. 12 B), as indeed has already been done in fig. 13. Each
+sheaf or band of active wires corresponding to a pole is thereby
+unaffected, but the advantages are gained that the axial length of the
+end-connexions is halved, and that they have less inductance. Thus if in
+fig. 11 there are four turns per coil, fig. 14 is electrically
+equivalent to it (save that the coils are here shown divided into two
+parallel paths, each carrying half the total current). When the large
+coils are divided as above described, it results that there are as many
+coils as there are poles, the outer loop of the small coil having a
+width equal to the pole-pitch, and the inner a width equal to the
+pole-face.
+
+[Illustration: FIG. 14.]
+
+Such is the form which the "single-phase alternator" takes, but since
+only one-half of the armature core is now covered with winding, an
+entirely distinct but similar set of coils may be wound to form a second
+armature circuit between the coils of the first circuit. The phase of
+this second circuit will differ by 90 deg. or a quarter of a period from
+that of the first, and it may either be used to feed an entirely
+separate external circuit possibly at a different pressure or, if it be
+composed of the same number of turns and therefore gives the same
+voltage, it may be interconnected with the first circuit to form a
+"quarter-phase alternator," as will be more fully described later. By an
+extension of the same process, if the width of each side of a coil is
+reduced to one-sixth of the pole-pitch, three armature circuits can be
+wound on the same core, and a "three-phase alternator," giving waves of
+E.M.F. differing in phase by 120 deg., is obtained.
+
+  The fundamental "electromotive-force equation" of the heteropolar
+  alternator can now be given a more definite form. Let Z_a be the
+  number of C. G. S. lines or the total flux, which issuing from any
+  one pole flows through the armature core, to leave it by another pole
+  of opposite sign. Since each active wire cuts these lines, first as
+  they enter the armature core and then as they emerge from it to enter
+  another pole, the total number of lines cut in one revolution by any
+  one active wire is 2pZ_a. The time in seconds taken by one revolution
+  is 60/N. The average E.M.F. induced in each active wire in one
+  revolution being proportional to the number of lines cut divided by
+  the time taken to cut them is therefore 2Z_a(pN/60) x 10^(-8) volts.
+  The active wires which are in series and form one distinct phase may
+  be divided into as many bands as there are poles; let each such band
+  contain t active wires, which as before explained may either form one
+  side of a single large coil or the adjacent sides of two coils when
+  the large coil is divided into two halves. Since the wires are joined
+  up into loops, two bands are best considered together, which with
+  either arrangement yield in effect a single coil of t turns. The
+  average E.M.F.'s of all the wires in the two bands when added together
+  will therefore be 4Z_a(pN/60)t x 10^(-8). But unless each band is
+  concentrated within a single slot, there must be some differential
+  action as they cross the neutral line between the poles, so that the
+  last expression is virtually the _gross_ average E.M.F. of the loops
+  on the assumption that the component E.M.F.'s always act in agreement
+  round the coil and do not at times partially neutralize one another.
+  The _net_ average E.M.F. of the coil as a whole, or the arithmetical
+  mean of all the instantaneous values of a half-wave of the actual
+  E.M.F. curve, is therefore reduced to an extent depending upon the
+  amount of differential action and so upon the width of the coil-side
+  when this is not concentrated. Let k' = the coefficient by which the
+  gross average E.M.F. must be multiplied to give the net average
+  E.M.F.; then k' may be called the "width-factor," and will have some
+  value less than unity when the wires of each band are spread over a
+  number of slots. The net average E.M.F. of the two bands corresponding
+  to a pair of poles is thus e_(av) = 4k'Z_a(pN/60)t x 10^(-8).
+
+  The shape of the curve of instantaneous E.M.F. of the coil must
+  further be taken into account. The "effective" value of an alternating
+  E.M.F. is equal to the square root of the mean square of its
+  instantaneous values, since this is the value of the equivalent
+  unidirectional and unvarying E.M.F., which when applied to a given
+  resistance develops energy at the same rate as the alternating E.M.F.,
+  when the effect of the latter is averaged over one or any whole number
+  of periods. Let k" = the ratio of the square root of the mean square
+  to the average E.M.F. of the coil, i.e. = effective E.M.F./average
+  E.M.F. Since it depends upon the shape of the E.M.F. curve, k" is also
+  known as the "form-factor"; thus if the length of gap between
+  pole-face and armature core and the spacing of the wires were so
+  graduated as to give a curve of E.M.F. varying after a sine law, the
+  form-factor would have the particular value of [pi]/2[root]2 = 1.11,
+  and to this condition practical alternators more or less conform. The
+  effective E.M.F. of the two bands corresponding to a pair of poles is
+  thus e_(eff) = 4k'k"Z_a(pN/60)t x 10^(-8).
+
+  In any one phase there are p pairs of bands, and these may be divided
+  into q parallel paths, where q is one or any whole number of which p
+  is a multiple. The effective E.M.F. of a complete phase is therefore
+  pe{eff}/q. Lastly, if m = the number of phases into which the armature
+  winding is divided, and [tau] = the total number of active wires on
+  the armature counted all round its periphery, t = [tau]/2pm, and the
+  effective E.M.F. per phase is E_a = 2k'k"Z_a(pN[tau]/60mq) x 10^(-8).
+
+  The two factors k' and k" may be united into one coefficient, and the
+  equation then takes its final form
+
+    E_a = 2KZ_a(pN[tau]/60mq) x 10^(-8) volts  (1a)
+
+  In the alternator q is most commonly 1, and there is only one circuit
+  per phase; finally the value of K or the product of the width-factor
+  and the form-factor usually falls between the limits of 1 and 1.25.
+
+We have next to consider the effect of the addition of more armature
+loops in the case of dynamos which give a unidirectional E.M.F. in
+virtue of their split-ring collecting device, i.e. of the type shown in
+fig. 7 with drum armature or its equivalent ring form. As before, if the
+additional loops are wound in continuation of the first as one coil
+connected to a single split-ring, this coil must be more or less
+concentrated into a narrow band; since if the width becomes nearly equal
+to or exceeds the width of the interpolar gap, the two edges of the
+coil-side will just as in the alternator act differentially against one
+another during part of each revolution. The drum winding with a single
+coil thus gives an armature of the H- or "shuttle" form invented by Dr
+Werner von Siemens. Although the E.M.F. of such an arrangement may have
+a much higher maximum value than that of the curve of fig. 7 for a
+single loop, yet it still periodically varies during each revolution and
+so gives a pulsating current, which is for most practical uses
+unsuitable. But such pulsation might be largely reduced if, for example,
+a second coil were placed at right angles to the original coil and the
+two were connected in series; the crests of the wave of E.M.F. of the
+second coil will then coincide with the hollows of the first wave,
+and although the maximum of the resultant curve of E.M.F. may be no
+higher its fluctuations will be greatly decreased. A spacial
+displacement of the new coils along the pole-pitch, somewhat as in a
+polyphase machine, thus suggests itself, and the process may be carried
+still further by increasing the number of equally spaced coils, provided
+that they can be connected in series and yet can have their connexion
+with the external circuit reversed as they pass the neutral line between
+the poles.
+
+[Illustration: FIG. 15.]
+
+[Illustration: FIG. 16.]
+
+Given two coils at right angles and with their split-rings displaced
+through a corresponding angle of 90 deg., they may be connected in series by
+joining one brush to the opposite brush of the second coil, the external
+circuit being applied to the two remaining brushes.[14] The same
+arrangement may again be repeated with another pair of coils in parallel
+with the first, and we thus obtain fig. 15 with four split-rings, their
+connexions to the loops being marked by corresponding numerals; the four
+coils will give the same E.M.F. as the two, but they will be jointly
+capable of carrying twice the current, owing to their division into two
+parallel circuits. Now in place of the four split-rings may be employed
+the greatly simplified four-segment structure shown in fig. 16, which
+serves precisely the same purpose as the four split-rings but only
+requires two instead of eight brushes. The effect of joining brush 2 in
+fig. 15 across to brush 3, brush 4 to brush 5, 5 to 6, &c., has
+virtually been to connect the end of coil A with the beginning of coil
+B, and the end of coil B with the beginning of coil A', and so on, until
+they form a continuous closed helix. Each sector of fig. 16 will
+therefore replace two halves of a pair of adjacent split-rings, if the
+end and beginning of a pair of adjacent coils are connected to it in a
+regular order of sequence. The four sectors are insulated from one
+another and from the shaft, and the whole structure is known as the
+"commutator,"[15] its function being not simply to collect the current
+but also to commute its direction in any coil as it passes the
+interpolar gap. The principle of the "closed-coil continuous-current
+armature" is thus reached, in which there are at least two parallel
+circuits from brush to brush, and from which a practically steady
+current can be obtained. Each coil is successively short-circuited, as a
+brush bridges over the insulation between the two sectors which
+terminate it; and the brushes must be so set that the period of
+short-circuit takes place when the coil is generating little or no
+E.M.F., i.e. when it is moving through the zone between the pole-tips.
+The effect of the four coils in reducing the percentage fluctuation of
+the E.M.F. is very marked, as shown at the foot of fig. 15 (where the
+upper curve is the resultant obtained by adding together the separate
+curves of coils A and B), and the levelling process may evidently be
+carried still further by the insertion of more coils and more
+corresponding sectors in the commutator, until the whole armature is
+covered with winding. For example, figs. 17 and 18 show a ring and a
+drum armature, each with eight coils and eight commutator sectors; their
+resultant curve, on the assumption that a single active wire gives the
+flat-topped curve of fig. 4, will be the upper wavy line of E.M.F.
+obtained by adding together two of the resultant curves of fig. 15, with
+a relative displacement of 45 deg.. The amount of fluctuation for a given
+number of commutator sectors depends upon the shape of the curve of
+E.M.F. yielded by the separate small sections of the armature winding;
+the greater the polar arc, the less the fluctuation. In practice, with a
+polar arc equal to about 0.75 of the pitch, any number of sectors over
+32 per pair of poles yields an E.M.F. which is sensibly constant
+throughout one or any number of revolutions.
+
+[Illustration: FIG. 17.]
+
+[Illustration: FIG. 18.]
+
+  The fundamental electro-motive-force equation of the
+  continuous-current heteropolar machine is easily obtained by analogy
+  from that of the alternator. The gross average E.W.F. from the two
+  sides of a drum loop without reference to its direction is as before
+  4Z_a(pN/60) x 10^(-8) volts. But for two reasons its net average
+  E.M.F. may be less; the span of the loop may be less than the
+  pole-pitch, so that even when the brushes are so set that the position
+  of short-circuit falls on the line where the field changes its
+  direction, the two sides of the loop for some little time act against
+  each other; or, secondly, even if the span of the loop be equal to the
+  pole-pitch, the brushes may be so set that the reversal of the
+  direction of its induced E.M.F. does not coincide with reversal of the
+  current by the passage of the coil under the brushes. The net average
+  E.M.F. of the loop is therefore proportional to the algebraic sum of
+  the lines which it cuts in passing from one brush to another, and this
+  is equal to the net amount of the flux which is included within the
+  loop when situated in the position of short-circuit under a brush. The
+  amount of this flux may be expressed as k'Z_a where k' is some
+  coefficient, less than unity if the span of the coil be less than the
+  pole-pitch, and also varying with the position of the brushes. The net
+  average E.M.F. of the loop is therefore
+
+    4k'Z_a(pN/60) x 10^(-8).
+
+  In practice the number of sections of the armature winding is so large
+  and their distribution round the armature periphery is so uniform,
+  that the sum total of the instantaneous E.M.F.'s of the several
+  sections which are in series becomes at any moment equal to the net
+  average E.M.F. of one loop multiplied by the number which are in
+  series. If the winding is divided into q parallel circuits, the number
+  of loops in series is [tau]/2q, so that the total E.M.F. is E_a =
+  2(k'/q)Z_a(pN/60)[tau] x 10^(-8) volts. Thus as compared with the
+  alternator not only is there no division of the winding into separate
+  phases, but the form-factor k' disappears, since the effective and
+  average E.M.F.'s are the same. Further whereas in the alternator q may
+  = 1, in the continuous-current closed-coil armature there can never be
+  less than two circuits in parallel from brush to brush, and if more,
+  their number must always be a multiple of two, so that q can never be
+  less than two and must always be an even number. Lastly, the factor k'
+  is usually so closely equal to 1, that the simplified equation may in
+  practice be adopted, viz.
+
+    E_a = (2/q)(ZpN/60)[tau] x 10^(-8) volts  (1b)
+
+  The fundamental equation of the electromotive force of the dynamo in
+  its fully developed forms (1 a) (and 1 b) may be compared with its
+  previous simple statement (1.). The three variable terms still find
+  their equivalents, but are differently expressed, the density B_g
+  being replaced by the total flux of one field Z_a, the length L of the
+  single active wire by the total number of such wires [tau], and the
+  velocity of movement V by the number of revolutions per second. Even
+  when the speed is fixed, an endless number of changes may be rung by
+  altering the relative values of the remaining two factors; and in
+  successful practice these may be varied between fairly wide limits
+  without detriment to the working or economy of the machine. While it
+  may be said that the equation of the E.M.F. was implicitly known from
+  Faraday's time onwards, the difficulty under which designers laboured
+  in early days was the problem of choosing the correct relation of Z_a
+  or [tau] for the required output; this, again, was due chiefly to the
+  difficulty of predetermining the total flux before the machine was
+  constructed. The general error lay in employing too weak a field and
+  too many turns on the armature, and credit must here be given to the
+  American inventors, E. Weston and T.A. Edison, for their early
+  appreciation of the superiority in practical working of the drum
+  armature, with comparatively few active wires rotating in a strong
+  field.
+
+
+  The armature core.
+
+_Continuous-current Dynamos._--On passing to the separate consideration
+of alternators and continuous-current dynamos, the chief constructive
+features of the latter will first be taken in greater detail. As already
+stated in the continuous-current dynamo the armature is usually the
+rotating portion, and the necessity of laminating its core has been
+generally described. The thin iron stampings employed to build up the
+core take the form of circular washers or "disks," which in small
+machines are strung directly on the shaft; in larger multipolar
+machines, in which the required radial depth of iron is small relatively
+to the diameter, a central cast iron hub supports the disks. Since the
+driving force is transmitted through the shaft to the disks, they must
+in the former case be securely fixed by keys sunk into the shaft; when a
+central hub is employed (fig. 19) it is keyed to the shaft, and its
+projecting arms engage in notches stamped on the inner circumference of
+the disks, or the latter have dovetailed projections fitting into the
+arms. The disks are then tightly compressed and clamped between stout
+end-plates so as to form a nearly solid iron cylinder of axial length
+slightly exceeding the corresponding dimension of the poles. If the
+armature is more than 4 ft. in diameter, the disks become too large to
+be conveniently handled in one piece, and are therefore made in
+segments, which are built up so as to break joint alternately. Prior to
+assemblage, the external circumference of each disk is notched in a
+stamping machine with the required number of slots to receive the
+armature coils, and the longitudinal grooves thereby formed in the
+finished core only require to have their sharp edges smoothed off so
+that there may be no risk of injury to the insulation of the coils.
+
+[Illustration: FIG. 19.]
+
+
+  Armature winding.
+
+With open slots either the armature coils may be encased with wrappings
+of oiled linen, varnished paper and thin flexible micanite sheeting in
+order to insulate them electrically from the iron slots in which they
+are afterwards embedded; or the slots may be themselves lined with
+moulded troughs of micanite, &c., for the reception of the armature
+coils, the latter method being necessary with half-closed slots.
+According to the nature of the coils armatures may be divided into the
+two classes of coil-wound and bar-wound. In the former class, round
+copper wire, double-cotton covered, is employed, and the coils are
+either wound by hand directly on to the armature core, or are shaped on
+formers prior to being inserted in the armature slots. Hand-winding is
+now only employed in very small bipolar machines, the process being
+expensive and accompanied by the disadvantage that if one section
+requires to be repaired, the whole armature usually has to be dismantled
+and re-wound. Former-wound coils are, on the other hand, economical in
+labour, perfectly symmetrical and interchangeable, and can be thoroughly
+insulated before they are placed in the slots. The shapers employed in
+the forming process are very various, but are usually arranged to give
+to the finished coil a lozenge shape, the two straight active sides
+which fit into the straight slots being joined by V-shaped ends; at each
+apex of the coil the wire is given a twist, so that the two sides fall
+into different levels, an upper and a lower, corresponding to the two
+layers which the coil-sides form on the finished armature. Rectangular
+wire of comparatively small section may be similarly treated, and if
+only one loop is required per section, wide and thin strip can be bent
+into a complete loop, so that the only soldered joints are those at the
+commutator end where the loops are interconnected. But finally with
+massive rectangular conductors, the transition must be made to
+bar-winding, in which each bar is a half-loop, insulated by being taped
+after it has been bent to the required shape; the separate bars are
+arranged on the armature in two layers, and their ends are soldered
+together subsequently to form loops. As a general rule, whether bars or
+former-wound coils are employed, the armature is barrel-wound, i.e. the
+end-connexions project outwards from the slots with but little change of
+level, so that they form a cylindrical mass supported on projections
+from the end-plates of the core (fig. 19); but, in certain cases, the
+end-connexions are bent downwards at right angles to the shaft, and they
+may then consist of separate strips of copper bent to a so-called
+butterfly or evolute shape.
+
+After the coils or loops have been assembled in the slots on the
+armature core, and the commutator has been fixed in place on the shaft,
+the soldering of the ends of the coils proceeds, by which at once the
+union of the end of one coil with the beginning of the next, and also
+their connexion to the commutator sectors, is effected, and in this lies
+the essential part of armature winding.
+
+[Illustration: FIG. 20.
+
+Lap-loops]
+
+
+    Lap-winding.
+
+  The development of the modern drum armature, with its numerous coils
+  connected in orderly sequence into a symmetrical winding, as
+  contrasted with the earlier Siemens armatures, was initiated by F. von
+  Hefner Alteneck (1871), and the laws governing the interconnexion of
+  the coils have now been elaborated into a definite system of winding
+  formulae. Whatever the number of wires or bars in each side of a coil,
+  i.e. whether it consist of a single loop or of many turns, the final
+  connexions of its free ends are not thereby affected, and it may be
+  mentally replaced by a single loop with two active inducing sides. The
+  coil-sides in their final position are thus to be regarded as separate
+  primary elements, even in number, and distributed uniformly round the
+  armature periphery or divided into small, equally spaced groups by
+  being located within the slots of a toothed armature. Attention must
+  then be directed simply to the span of the back connexion between the
+  elements at the end of the armature further from the commutator, and
+  to the span of the front connexion by which the last turn of a coil is
+  finally connected to the first turn of the next in sequence, precisely
+  as if each coil of many turns were reduced to a single loop. In order
+  to avoid direct differential action, the span of the back connexion
+  which fixes the width of the coil must exceed the width of the
+  pole-face, and should not be far different from the pole-pitch; it is
+  usually a little less than the pole-pitch. Taking any one element as
+  No. 1 in fig. 20, where for simplicity a smooth-core bipolar armature
+  is shown, the number of winding-spaces, each to be occupied by an
+  element, which must be counted off in order to find the position of
+  the next element in series, is called the "pitch" of the
+  end-connexion, front or back, as the case may be. Thus the back pitch
+  of the winding as marked by the dotted line in fig. 20 is 7, the
+  second side of the first loop being the element numbered 1 + 7 = 8. In
+  forming the front end-connexion which completes the loop and joins it
+  to the next in succession, two possible cases present themselves. By
+  the first, or "lap-winding," the front end-connexion is brought
+  backwards, and passing on its way to a junction with a commutator
+  sector is led to a third element lying within the two sides of the
+  first loop, i.e. the second loop starts with the element, No. 3, lying
+  next but one to the starting-point of the first loop. The winding
+  therefore returns backwards on itself to form each front end, but as a
+  whole it works continually forwards round the armature, until it
+  finally "re-enters," after every element has been traversed. The
+  development of the completed winding on a flat surface shows that it
+  takes the form of a number of partially overlapping loops, whence its
+  name originates. The firm-line portion of fig. 21 gives the
+  development of an armature similar to that of fig. 18 when cut through
+  at the point marked X and opened out; two of the overlapping loops are
+  marked thereon in heavy lines. The multipolar lap-wound armature is
+  obtained by simply repeating the bipolar winding p times, as indicated
+  by the dotted additions of fig. 21 which convert it from a two-pole to
+  a four-pole machine. The characteristic feature of the lap-wound
+  armature is that there are as many parallel paths from brush to brush,
+  and as many points at which the current must be collected, as there
+  are poles. As the bipolar closed-coil continuous-current armature has
+  been shown to consist in reality of two circuits in parallel, each
+  giving the same E.M.F. and carrying half the total current, so the
+  multipolar lap-wound drum consists of p pairs of parallel paths, each
+  giving the same E.M.F. and carrying 1/2p of the total current. Thus in
+  equation 1.b we have q = 2p, and the special form which the _E.M.F.
+  equation of the lap-wound armature_ takes is E_[alpha] = Z_a
+  (N/60)[tau] x 10^(-8) volts. All the brushes which are of the same
+  sign must be connected together in order to collect the total armature
+  current. The several brush-sets of the multipolar lap-wound machine
+  may again be reduced to two by "cross-connexion" of sectors situated
+  360 deg./p apart, but this is seldom done, since the commutator must then
+  be lengthened p times in order to obtain the necessary brush
+  contact-surface for the collection of the entire current.
+
+  [Illustration: FIG. 21.]
+
+  [Illustration: FIG. 22.
+
+  Wave-loops]
+
+  [Illustration: FIG. 23.]
+
+
+    Wave-winding.
+
+  But for many purposes, especially where the voltage is high and the
+  current small, it is advantageous to add together the inductive effect
+  of the several poles of the multipolar machine by throwing the E.M.F's
+  of half the total number of elements into series, the number of
+  parallel circuits being conversely again reduced to two. This is
+  effected by the second method of winding the closed-coil continuous
+  current drum, which is known as "wave-winding." The front pitch is now
+  in the same direction round the armature as the back pitch (fig. 22),
+  so that the beginning of the second loop, i.e. element No. 15, lies
+  outside the first loop. After p loops have been formed and as many
+  elements have been traversed as there are poles, the distance covered
+  either falls short of or exceeds a complete tour of the armature by
+  two winding-spaces, or the width of two elements. A second and third
+  tour are then made, and so on, until finally the winding again closes
+  upon itself. When the completed winding is developed as in fig. 23, it
+  is seen to work continuously forwards round the armature in zigzag
+  waves, one of which is marked in heavy lines, and the number of
+  complete tours is equal to the average of the back and front pitches.
+  Since the number of parallel circuits from brush to brush is q = 2,
+  the _E.M.F. equation of the wave-wound drum_ is E_a = pZ_a (N/60)[tau]
+  x 10^(-8) volts. Only two sets of brushes are necessary, but in order
+  to shorten the length of the commutator, other sets may also be added
+  at the point of highest and lowest potential up to as many in number
+  as there are poles. Thus the advantage of the wave-wound armature is
+  that for a given voltage and number of poles the number of active
+  wires is only 1/p of that in the lap-wound drum, each being of larger
+  cross-section in order to carry p times as much current; hence the
+  ratio of the room occupied by the insulation to the copper area is
+  less, and the available space is better utilized. A further advantage
+  is that the two circuits from brush to brush consist of elements
+  influenced by all the poles, so that if for any reason, such as
+  eccentricity of the armature within the bore of the pole-pieces, or
+  want of uniformity in the magnetic qualities of the poles, the flux of
+  each field is not equal to that of every other, the equality of the
+  voltage produced by the two halves of the winding is not affected
+  thereby.
+
+  In appearance the two classes of armatures, lap and wave, may be
+  distinguished in the barrel type of winding by the slope of the upper
+  layer of back end-connexions, and that of the front connexions at the
+  commutator end being parallel to one another in the latter, and
+  oppositely directed in the former.
+
+[Illustration: FIG. 24.]
+
+After completion of the winding, the end-connexions are firmly bound
+down by bands of steel or phosphor bronze binding wire, so as to resist
+the stress of centrifugal force. In the case of smooth-surface
+armatures, such bands are also placed at intervals along the length of
+the armature core, but in toothed armatures, although the coils are
+often in small machines secured in the slots by similar bands of a
+non-magnetic high-resistance wire, the use of hard-wood wedges driven
+into notches at the sides of the slots becomes preferable, and in very
+large machines indispensable. The external appearance of a typical
+armature with lap-winding is shown in fig. 24.
+
+
+  The commutator.
+
+A sound mechanical construction of the commutator is of vital importance
+to the good working of the continuous-current dynamo. The narrow,
+wedge-shaped sectors of hard-drawn copper, with their insulating strips
+of thin mica, are built up into a cylinder, tightly clamped together,
+and turned in the lathe; at each end a V-shaped groove is turned, and
+into these are fitted rings of micanite of corresponding section (fig.
+19); the whole is then slipped over a cast iron sleeve, and at either
+end strong rings are forced into the V-shaped grooves under great
+pressure and fixed by a number of closely-pitched tightening bolts. In
+dynamos driven by steam-turbines in which the peripheral speed of the
+commutator is very high, rings of steel are frequently shrunk on the
+surface of the commutator at either end and at its centre. But in every
+case the copper must be entirely insulated from the supporting body of
+metal by the interposition of mica or micanite and the prevention of any
+movement of the sectors under frequent and long-continued heating and
+cooling calls for the greatest care in both the design and the
+manufacture.
+
+
+  Forms of field-magnet.
+
+On passing to the second fundamental part of the dynamo, namely, the
+field-magnet, its functions may be briefly recalled as follows:--It has
+to supply the magnetic flux; to provide for it an iron path as nearly
+closed as possible upon the armature, save for the air-gaps which must
+exist between the pole-system and the armature core, the one stationary
+and the other rotating; and, lastly, it has to give the lines such
+direction and intensity within the air-gaps that they may be cut by the
+armature wires to the best advantage. Roughly corresponding to the three
+functions above summarized are the three portions which are more or less
+differentiated in the complete structure. These are: (1) the magnet
+"cores" or "_limbs_," carrying the exciting coils whereby the inert iron
+is converted into an electro-magnet; (2) the _yoke_, which joins the
+limbs together and conducts the flux between them; and (3) the
+_pole-pieces_, which face the armature and transmit the lines from the
+limbs through the air-gap to the armature core, or vice versa.
+
+  [Illustration: FIG. 25.]
+
+  Of the countless shapes which the field-magnet may take, it may be
+  said, without much exaggeration, that almost all have been tried; yet
+  those which have proved economical and successful, and hence have met
+  with general adoption, may be classed under a comparatively small
+  number of types. For bipolar machines the _single horse-shoe_ (fig.
+  25), which is the lineal successor of the permanent magnet employed in
+  the first magneto-electric machines, was formerly very largely used.
+  It takes two principal forms, according as the pole-pieces and
+  armature are above or beneath the magnet limbs and yoke. The
+  "over-type" form is best suited to small belt-driven dynamos, while
+  the "under-type" is admirably adapted to be directly driven by the
+  steam-engine, the armature shaft being immediately coupled to the
+  crank-shaft of the engine. In the latter case the magnet must be
+  mounted on non-magnetic supports of gun-metal or zinc, so as to hold
+  it at some distance away from the iron bedplate which carries both
+  engine and dynamo; otherwise a large proportion of the flux which
+  passes through the magnet limbs would leak through the bedplate across
+  from pole to pole without passing through the armature core, and so
+  would not be cut by the armature wires.
+
+  [Illustration: FIG. 26.]
+
+  Next may be placed the "Manchester" field (fig. 26)--the type of a
+  divided magnetic circuit in which the flux forming one field or pole
+  is divided between two magnets. An exciting coil is placed on each
+  half of the double horse-shoe magnet, the pair being so wound that
+  consequent poles are formed above and below the armature. Each magnet
+  thus carries one-half of the total flux, the lines of the two halves
+  uniting to form a common field where they issue forth into or leave
+  the air-gaps. The pole-pieces may be lighter than in the single
+  horse-shoe type, and the field is much more symmetrical, whence it is
+  well suited to ring armatures of large diameter. Yet these advantages
+  are greatly discounted by the excessive magnetic leakage, and by the
+  increased weight of copper in the exciting coils. Even if the greater
+  percentage which the leakage lines bear to the useful flux is
+  neglected, and the cross sectional area of each magnet core is but
+  half that of the equivalent single horse-shoe, the weight of wire in
+  the double magnet for the same rise of temperature in the coils must
+  be some 40% more than in the single horse-shoe, and the rate at which
+  energy is expended in heating the coils will exceed that of the single
+  horse-shoe in the same proportion.
+
+  Thirdly comes the two-pole _ironclad_ type, so called from the
+  exciting coil being more or less encased by the iron yoke; this latter
+  is divided into two halves, which pass on either side of the armature.
+  Unless the yoke be kept well away from the polar edges and armature,
+  the leakage across the air into the yoke becomes considerable,
+  especially if only one exciting coil is used, as in fig. 27 A; it is
+  better, therefore, to divide the excitation between two coils, as in
+  fig. 27 B, when the field also becomes symmetrical.
+
+  From this form is easily derived the _multipolar_ type of fig. 28 or
+  fig. 29, which is by far the most usual for any number of poles from
+  four upwards; its leakage coefficient is but small, and it is
+  economical in weight both of iron and copper.
+
+
+    Materials of magnets.
+
+  As regards the materials of which magnets are made, generally speaking
+  there is little difference in the permeability of "wrought iron" or
+  "mild steel forgings" and good "cast steel"; typical (B, H) curves
+  connecting the magnetizing force required with different
+  flux-densities for these materials are given under ELECTROMAGNETISM.
+  On the other hand there is a marked inferiority in the case of "cast
+  iron," which for a flux-density of B = 8000 C.G.S. lines per sq. cm.
+  requires practically the same number of ampere-turns per centimetre
+  length as steel requires for B = 16,000. Whatever the material, if the
+  flux-density be pressed to a high value the ampere-turns are very
+  largely increased owing to its approaching saturation, and this
+  implies either a large amount of copper in the field coils or an undue
+  expenditure of electrical energy in their excitation. Hence there is a
+  limit imposed by practical considerations to the density at which the
+  magnet should be worked, and this limit may be placed at about B =
+  16,000 for wrought iron or steel, and at half this value for cast
+  iron. For a given flux, therefore, the cast iron magnet must have
+  twice the sectional area and be twice as heavy, although this
+  disadvantage is partly compensated by its greater cheapness. If,
+  however, cast iron be used for the portion of the magnetic circuit
+  which is covered with the exciting coils, the further disadvantage
+  must be added that the weight of copper on the field-magnet is much
+  increased, so that it is usual to employ forgings or cast steel for
+  the magnet cores on which the coils are wound. If weight is not a
+  disadvantage, a cast iron yoke may be combined with the wrought iron
+  or cast steel magnet cores. An absence of joints in the magnetic
+  circuit is only desirable from the point of view of economy of expense
+  in machining the component parts during manufacture; when the surfaces
+  which abut against each other are drawn firmly together by screws, the
+  want of homogeneity at the joint, which virtually amounts to the
+  presence of a very thin film of air, produces little or no effect on
+  the total reluctance by comparison with the very much longer air-gaps
+  surrounding the armature. In order to reduce the eddy-currents in the
+  pole-pieces, due to the use of toothed armatures with relatively wide
+  slots, the poles themselves must be laminated, or must have fixed to
+  them laminated pole-shoes, built up of thin strips of mild steel
+  riveted together (as shown in fig. 29).
+
+  [Illustration: FIG. 27.]
+
+  [Illustration: FIG. 28.]
+
+  However it be built up, the mechanical strength of the magnet system
+  must be carefully considered. Any two surfaces between which there
+  exists a field of density B_g experience a force tending to draw them
+  together proportional to the square of the density, and having a value
+  of B_g squared/(1.735 x 10^6) lb. per sq. in. of surface, over which the
+  density may be regarded as having the uniform value B_g. Hence, quite
+  apart from the torque with which the stationary part of the dynamo
+  tends to turn with the rotating part as soon as current is taken out
+  of the armature, there exists a force tending to make the pole-pieces
+  close on the armature as soon as the field is excited. Since both
+  armature and magnet must be capable of resisting this force, they
+  require to be rigidly held; although the one or the other must be
+  capable of rotation, there should otherwise be no possibility of one
+  part of the magnetic circuit shifting relatively to any other part. An
+  important conclusion may be drawn from this circumstance. If the
+  armature be placed exactly concentric within the bore of the poles,
+  and the two or more magnetic fields be symmetrical about a line
+  joining their centres, there is no tendency for the armature core to
+  be drawn in one direction more than in another; but if there is any
+  difference between the densities of the several fields, it will cause
+  an unbalanced stress on the armature and its shaft, under which it
+  will bend, and as this bending is continually reversed relatively to
+  the fibres of the shaft, they will eventually become weakened and give
+  way. Especially is this likely to take place in dynamos with short
+  air-gaps, wherein any difference in the lengths of the air-gaps
+  produces a much greater percentage difference in the flux-density than
+  in dynamos with long air-gaps. In toothed armatures with short
+  air-gaps the shaft must on this account be sufficiently strong to
+  withstand the stress without appreciable bending.
+
+
+  The magnetic circuit.
+
+Reference has already been made to the importance in dynamo design of
+the _predetermination of the flux_ due to a given number of ampere-turns
+wound on the field-magnet, or, conversely, of the number of ampere-turns
+which must be furnished by the exciting coils in order that a certain
+flux corresponding to one field may flow through the armature core from
+each pole. An equally important problem is the correct proportioning of
+the field-magnet, so that the useful flux Z_a may be obtained with the
+greatest economy in materials and exciting energy. The key to the two
+problems is to be found in the concept of a magnetic circuit as
+originated by H.A. Rowland and R.H.M. Bosanquet;[16] and the full
+solution of both may be especially connected with the name of Dr J.
+Hopkinson, from his practical application of the concept in his design
+of the Edison-Hopkinson machine, and in his paper on "Dynamo-Electric
+Machinery."[17] The publication of this paper in 1886 begins the second
+era in the history of the dynamo; it at once raised its design from the
+level of empirical rules-of-thumb to a science, and is thus worthy to be
+ranked as the necessary supplement of the original discoveries of
+Faraday. The process of predetermining the necessary ampere-turns is
+described in a simple case under ELECTROMAGNETISM. In its extension to
+the complete dynamo, it consists merely in the division of the magnetic
+circuit into such portions as have the same sectional area and
+permeability and carry approximately the same total flux; the difference
+of magnetic potential that must exist between the ends of each section
+of the magnet in order that the flux may pass through it is then
+calculated _seriatim_ for the several portions into which the magnetic
+circuit is divided, and the separate items are summed up into one
+magnetomotive force that must be furnished by the exciting coils.
+
+[Illustration: FIG. 29.]
+
+  The chief sections of the magnetic circuit are (1) the air-gaps, (2)
+  the armature core, and (3) the iron magnet.
+
+  The _air-gap_ of a dynamo with smooth-core armature is partly filled
+  with copper and partly with the cotton, mica, or other materials used
+  to insulate the core and wires; all these substances are, however,
+  sensibly non-magnetic, so that the whole interferric gap between the
+  iron of the pole-pieces and the iron of the armature may be treated as
+  an air-space, of which the permeability is constant for all values of
+  the flux density, and in the C.G.S. system is unity. Hence if l_g and
+  A_g be the length and area of the single air-gap in cm. and sq. cm.,
+  the reluctance of the double air-gap is 2l_g/A_g, and the difference
+  of magnetic potential required to pass Z_a lines over this reluctance
+  is Z_a.2l_g/A_g = B_g.2l_g; or, since one ampere-turn gives 1.257
+  C.G.S. units of magnetomotive force, the exciting power in
+  ampere-turns required over the two air-gaps is X_g = B_g.2l_g/1.257 =
+  0.8 B_g.2l_g. In the determination of the area A_g small allowance
+  must be made for the fringe of lines which extend beyond the actual
+  polar face. In the toothed armature with open slots, the lines are no
+  longer uniformly distributed over the air-gap area, but are graduated
+  into alternate bands of dense and weak induction corresponding to the
+  teeth and slots. Further, the lines curve round into the sides of the
+  teeth, so that their average length of path in the air and the air-gap
+  reluctance is not so easily calculated. Allowance must be made for
+  this by taking an increased length of air-gap = ml_g, where m is the
+  ratio _maximum density/mean density_, of which the value is chiefly
+  determined by the ratios of the width of tooth to width of slot and of
+  the width of slot to the air-gap between pole-face and surface of the
+  armature core.
+
+  The _armature core_ must be divided into the teeth and the core proper
+  below the teeth. Owing to the tapering section of the teeth, the
+  density rises towards their root, and when this reaches a high value,
+  such as 18,000 or more lines per sq. cm., the saturation of the iron
+  again forces an increasing proportion of the lines outwards into the
+  slot. A distinction must then be drawn between the "apparent"
+  induction which would hold if all the lines were concentrated in the
+  teeth, and the "real" induction. The area of the iron is obtained by
+  multiplying the number of teeth under the pole-face by their width and
+  by the net length of the iron core parallel to the axis of rotation.
+  The latter is the gross length of the armature less the space lost
+  through the insulating varnish or paper between the disks or through
+  the presence of ventilating ducts, which are introduced at intervals
+  along the length of the core. The former deduction averages about 7 to
+  10% of the gross length, while the latter, especially in large
+  multipolar machines, is an even more important item. Alter calculating
+  the density at different sections of the teeth, reference has now to
+  be made to a (B, H) or flux-density curve, from which may be found the
+  number of ampere-turns required per cm. length of path. This number
+  may be expressed as a function of the density in the teeth, and f(B_t)
+  be its average value over the length of a tooth, the ampere-turns of
+  excitation required over the teeth on either side of the core as the
+  lines of one field enter or leave the armature is X_t = f(B_t).2l_t,
+  where l_t is the length of a single tooth in cm.
+
+  In the core proper below the teeth the length of path continually
+  shortens as we pass from the middle of the pole towards the centre
+  line of symmetry. On the other hand, as the lines gradually accumulate
+  in the core, their density increases from zero midway under the poles
+  until it reaches a maximum on the line of symmetry. The two effects
+  partially counteract one another, and tend to equalize the difference
+  of magnetic potential required over the paths of varying lengths; but
+  since the reluctivity of the iron increases more rapidly than the
+  density of the lines, we may approximately take for the length of path
+  (l_a) the minimum peripheral distance between the edges of adjacent
+  pole-faces, and then assume the maximum value of the density of the
+  lines as holding throughout this entire path. In ring and drum
+  machines the flux issuing from one pole divides into two halves in the
+  armature core, so that the maximum density of lines in the armature is
+  B_a = Z_a/2ab, where a = the radial depth of the disks in centimetres
+  and b = the net length of iron core. The total exciting power required
+  between the pole-pieces is therefore, at no load, X_p = X_g + X_t +
+  X_a, where X_a = f(B_a).l_a; in order, however, to allow for the
+  effect of the armature current, which increases with the load, a
+  further term X_b, must be added.
+
+  [Illustration: Fig. 30.]
+
+  In the continuous-current dynamo it may be, and usually is, necessary
+  to move the brushes forward from the interpolar line of symmetry
+  through a small angle in the direction of rotation, in order to avoid
+  sparking between the brushes and the commutator (_vide infra_). When
+  the dynamo is giving current, the wires on either side of the diameter
+  of commutation form a current-sheet flowing along the surface of the
+  armature from end to end, and whatever the actual end-connexions of
+  the wires, the wires may be imagined to be joined together into a
+  system of loops such that the two sides of each loop are carrying
+  current in opposite directions. Thus a number of armature ampere-turns
+  are formed, and their effect on the entire system of magnet and
+  armature must be taken into account. So long as the diameter of
+  commutation coincides with the line of symmetry, the armature may be
+  regarded as a cylindrical electromagnet producing a flux of lines, as
+  shown in fig. 30. The direction of the self-induced flux in the
+  air-gaps is the same as that of the lines of the external field in one
+  quadrant on one side of DC, but opposed to it in the other quadrant on
+  the same side of DC; hence in the resultant field due to the combined
+  action of the field-magnet and armature ampere-turns, the flux is as
+  much strengthened over the one half of each polar face as it is
+  weakened over the other, and the total number of lines is unaffected,
+  although their distribution is altered. The armature ampere-turns are
+  then called _cross-turns_, since they produce a cross-field, which,
+  when combined with the symmetrical field, causes the leading
+  pole-corners ll to be weakened and the trailing pole-corners tt to be
+  strengthened, the neutral line of zero field being thus twisted
+  forwards in the direction of rotation. But when the brushes and
+  diameter of commutation are shifted forward, as shown in fig. 31, it
+  will be seen that a number of ampere-turns, forming a zone between the
+  lines Dn and mC, are in effect wound immediately on the magnetic
+  circuit proper, and this belt of ampere-turns is in direct opposition
+  to the ampere-turns of the field, as shown by the dotted and crossed
+  wires on the pole-pieces. The armature ampere-turns are then divisible
+  into the two bands, the _back-turns_, included within twice the angle
+  of lead [lambda], weakening the field, and the cross-turns, bounded by
+  the lines Dm, nC, again producing distortion of the weakened
+  symmetrical field. If, therefore, a certain flux is to be passed
+  through the armature core in opposition to the demagnetizing turns,
+  the difference of magnetic potential between the pole-faces must
+  include not only X_a, X_t, and X_g, but also an item X_b, in order to
+  balance the "back" ampere-turns of the armature. The amount by which
+  the brushes must be shifted forward increases with the armature
+  current, and in corresponding proportion the back ampere-turns are
+  also increased, their value being c[tau]2[lambda]/360 deg., where c = the
+  current carried by each of the [tau] active wires. Thus the term X_b,
+  takes into account the effect of the armature reaction on the total
+  flux; it varies as the armature current and angle of lead required to
+  avoid sparking are increased; and the reason for its introduction in
+  the fourth place (X_p = X_g + X_t + X_a + X_b), is that it increases
+  the magnetic difference of potential which must exist between the
+  poles of the dynamo, and to which the greater part of the leakage is
+  due. The leakage paths which are in parallel with the armature across
+  the poles must now be estimated, and so a new value be derived for the
+  flux at the commencement of the _iron-magnet_ path. If P = their joint
+  permeance, the leakage flux due to the difference of potential at the
+  poles is z_l = 1.257X_p x P, and this must be added to the useful flux
+  Z_a, or Z_p = Z_a + Z_l. There are also certain leakage paths in
+  parallel with the magnet cores, and upon the permeance of these a
+  varying number of ampere-turns is acting as we proceed along the
+  magnet coils; the magnet flux therefore increases by the addition of
+  leakage along the length of the limbs, and finally reaches a maximum
+  near the yoke. Either, then, the density in the magnet B_m = Z_m/A_m
+  will vary if the same sectional area be retained throughout, or the
+  sectional area of the magnet must itself be progressively increased.
+  In general, sufficient accuracy will be obtained by assuming a certain
+  number of additional leakage lines z_n as traversing the entire length
+  of magnet limbs and yoke (= l_m), so that the density in the magnet
+  has the uniform value B_m = (Z_p + z_n)/A_m. The leakage flux added on
+  actually within the length of the magnet core or z_n will be
+  approximately equal to half the total M.M.F. of the coils multiplied
+  by the permeance of the leakage paths around one coil. The
+  corresponding value of H can then be obtained from the (B, H) curve of
+  the material of which the magnet is composed, and the ampere-turns
+  thus determined must be added to X_p, or X = X_p + X_m, where X_m =
+  f(B_m)l_m. The final equation for the exciting power required on a
+  magnetic circuit as a whole will therefore take the form
+
+    X = A[Tau] = 0.8B_g.2l_g + f(B_t)2l_t + f(B_a)l_a + X_b + f(B_m)l_m. (3)
+
+  If the magnet cores are of wrought iron or cast steel, and the yoke is
+  of cast iron, the last term must be divided into two portions
+  corresponding to the different materials, i.e. into f(B_m)l_m +
+  f(B_y)l_y. In the ordinary multipolar machine with as many
+  magnet-coils as there are poles, each coil must furnish half the above
+  number of ampere-turns.
+
+  [Illustration: FIG. 31.]
+
+
+    Magnetic leakage.
+
+  Since no substance is impermeable to the passage of magnetic flux, the
+  only form of magnetic circuit free from leakage is one uniformly wound
+  with ampere-turns over its whole length. The reduction of the
+  _magnetic leakage_ to a minimum in any given type is therefore
+  primarily a question of distributing the winding as far as possible
+  uniformly upon the circuit, and as the winding must be more or less
+  concentrated into coils, it resolves itself into the necessity of
+  introducing as long air-paths as possible between any surfaces which
+  are at different magnetic potentials. No iron should be brought near
+  the machine which does not form part of the magnetic circuit proper,
+  and especially no iron should be brought near the poles, between which
+  the difference of magnetic potential practically reaches its maximum
+  value. In default of a machine of the same size or similar type on
+  which to experiment, the probable direction of the leakage flux must
+  be assumed from the drawing, and the air surrounding the machine must
+  be mapped out into areas, between which the permeances are calculated
+  as closely as possible by means of such approximate formulae as those
+  devised by Professor G. Forbes.
+
+
+    Excitation of field-magnet.
+
+  In the earliest "magneto-electric" machines permanent steel magnets,
+  either simple or compound, were employed, and for many years these
+  were retained in certain alternators, some of which are still in use
+  for arc lighting in lighthouses. But since the field they furnish is
+  very weak, a great advance was made when they were replaced by soft
+  iron electromagnets, which could be made to yield a much more intense
+  flux. As early as 1831 Faraday[18] experimented with electromagnets,
+  and after 1850 they gradually superseded the permanent magnet. When
+  the total ampere-turns required to excite the electromagnet have been
+  determined, it remains to decide how the excitation shall be obtained;
+  and, according to the method adopted, continuous-current machines may
+  be divided into four well-defined classes.
+
+  [Illustration: FIG. 32.]
+
+  The simplest method, and that which was first used, is _separate
+  excitation_ from some other source of direct current, which may be
+  either a primary or a secondary battery or another dynamo (fig. 32).
+  But since the armature yields a continuous current, it was early
+  suggested (by J. Brett in 1848 and F. Sinsteden in 1851) that this
+  current might be utilized to increase the flux; combinations of
+  permanent and electromagnets were therefore next employed, acting
+  either on the main armature or on separate armatures, until in 1867 Dr
+  Werner von Siemens and Sir C. Wheatstone almost simultaneously
+  discovered that the dynamo could be made _self-exciting_ through the
+  residual magnetism retained in the soft iron cores of the
+  electromagnet. The former proposed to take the whole of the current
+  round the magnet coils which were in series with the armature and
+  external circuit, while the latter proposed to utilize only a portion
+  derived by a shunt from the main circuit; we thus arrive at the second
+  and third classes, namely, _series_ and _shunt_ machines. The starting
+  of the process of excitation in either case is the same; when the
+  brushes are touching the commutator and the armature is rotated, the
+  small amount of flux left in the magnet is cut by the wires, and a
+  very small current begins to flow round the closed circuit; this
+  increases the flux, which in turn further increases the E.M.F. and
+  current, until, finally, the cumulative effect stops through the
+  increasing saturation of the iron cores. Fig. 33, illustrating the
+  _series_ machine, shows the winding of the exciting coils to be
+  composed of a few turns of thick wire. Since the current is undivided
+  throughout the whole circuit, the resistance of both the armature and
+  field-magnet winding must be low as compared with that of the external
+  circuit, if the useful power available at the terminals of the machine
+  is to form a large percentage of the total electrical power--in other
+  words, if the efficiency is to be high. Fig. 34 shows the third
+  method, in which the winding of the field-magnets is a _shunt_ or
+  fine-wire circuit of many turns applied to the terminals of the
+  machine; in this ease the resistance of the shunt must be high as
+  compared with that of the external circuit, in order that only a small
+  proportion of the total energy may be absorbed in the field.
+
+  [Illustration: FIG. 33.]
+
+  [Illustration: FIG. 34.]
+
+  Since the whole of the armature current passes round the field-magnet
+  of the series machine, any alteration in the resistance of the
+  external circuit will affect the excitation and also the voltage. A
+  curve connecting together corresponding values of external current and
+  terminal voltage for a given speed of rotation is known as the
+  _external-characteristic_ of the machine; in its main features it has
+  the same appearance as a curve of magnetic flux, but when the current
+  exceeds a certain amount it begins to bend downwards and the voltage
+  decreases. The reason for this will be found in the armature reaction
+  at large loads, which gradually produces a more and more powerful
+  demagnetizing effect, as the brushes are shifted forwards to avoid
+  sparking; eventually the back ampere-turns overpower any addition to
+  the field that would otherwise be due to the increased current flowing
+  round the magnet. The "external characteristic" for a shunt machine
+  has an entirely different shape. The field-magnet circuit being
+  connected in parallel with the external circuit, the exciting current,
+  if the applied voltage remains the same, is in no way affected by
+  alterations in the resistance of the latter. As, however, an increase
+  in the external current causes a greater loss of volts in the armature
+  and a greater armature reaction, the terminal voltage, which is also
+  the exciting voltage, is highest at no load and then diminishes. The
+  fall is at first gradual, but after a certain critical value of the
+  armature current is reached, the machine is rapidly demagnetized and
+  loses its voltage entirely.
+
+  [Illustration: FIG. 35.]
+
+  The last method of excitation, namely, _compound-winding_ (fig. 35),
+  is a combination of the two preceding, and was first used by S.A.
+  Varley and by C.F. Brush. If a machine is in the first instance
+  shunt-wound, and a certain number of series-turns are added, the
+  latter, since they carry the external current, can be made to
+  counteract the effect which the increased external current would have
+  in lowering the voltage of the simple shunt machine. The ampere-turns
+  of the series winding must be such that they not only balance the
+  increase of the demagnetizing back ampere-turns on the armature, but
+  further increase the useful flux, and compensate for the loss of volts
+  over their own resistance and that of the armature. The machine will
+  then give for a constant speed a nearly constant voltage at its
+  terminals, and the curve of the external characteristic becomes a
+  straight line for all loads within its capacity. Since with most prime
+  movers an increase of the load is accompanied by a drop in speed, this
+  effect may also be counteracted; while, lastly, if the series-turns
+  are still further increased, the voltage may be made to rise with an
+  increasing load, and the machine is "over-compounded."
+
+
+  Commutation and sparking at the brushes.
+
+At the initial moment when an armature coil is first short-circuited by
+the passage of the two sectors forming its ends under the contact
+surface of a brush, a certain amount of electromagnetic energy is stored
+up in its magnetic field as linked with the ampere-turns of the coil
+when carrying its full share of the total armature current. During the
+period of short-circuit this quantity of energy has to be dissipated as
+the current falls to zero, and has again to be re-stored as the current
+is reversed and raised to the same value, but in the opposite direction.
+The period of short-circuit as fixed by the widths of the brush and of
+the mica insulation between the sectors, and by the peripheral speed of
+the commutator is extremely brief, and only lasts on an average from
+(1/200)th to (1/1000)th of a second. The problem of sparkless
+commutation is therefore primarily a question of our ability to
+dissipate and to re-store the required amount of energy with sufficient
+rapidity.
+
+An important aid towards the solution of this problem is found in the
+effect of the varying contact-resistance between the brush and the
+surfaces of the leading and trailing sectors which it covers. As the
+commutator moves under the brush, the area of contact which the brush
+makes with the leading sector diminishes, and the resistance between the
+two rises; conversely, the area of contact between the brush and the
+trailing sector increases and the resistance falls. This action tends
+automatically to bring the current through each sector into strict
+proportionality to the amount of its surface which is covered by the
+brush, and so to keep the current-density and the loss of volts over the
+contacts uniform and constant. As soon as the current-density in the two
+portions of the brush becomes unequal, a greater amount of heat is
+developed at the commutator surface, and this in the first place affords
+an additional outlet for the dissipation of the stored energy of the
+coil, while after reversal of the current it is the accompaniment of a
+re-storage of the required energy. This energy, as well as that which is
+spent in heating the coil, can in fact, in default of other sources, be
+derived through the action of the unequal current-density from the
+electrical output of the rest of the armature winding, and so only
+indirectly from the prime mover.
+
+In practice, when the normal contact-resistance of the brushes is low
+relatively to the resistance of the coil, as is the case with metal
+brushes of copper or brass gauze, but little benefit can be obtained
+from the action of the varying contact-resistance. It exerts no
+appreciable effect until close towards the end of the period of
+short-circuit, and then only with such a high-current-density at the
+trailing edge of the leaving sector that at the moment of parting the
+brush-tip is fused, or its metal volatilized, and sparking has in fact
+set in. With such brushes, then, it becomes necessary to call in the aid
+of a reversing E.M.F. impressed upon the coil by the magnetic field
+through which it is moving. If such a reversing field comes into action
+while the current is still unreversed, its E.M.F. is opposed to the
+direction of the current, and the coil is therefore driving the armature
+forward as in a motor; it thus affords a ready means of rapidly
+dissipating part of the initial energy in the form of mechanical work
+instead of as heat. After the current has been reversed, the converse
+process sets in, and the prime mover directly expends mechanical energy
+not only in heating the coil, but also in storing up electromagnetic
+energy with a rapidity dependent upon the strength of the reversing
+field. The required direction of external field can be obtained in the
+dynamo by shifting the brushes forward, so that the short-circuited coil
+enters into the fringe of lines issuing from the leading pole-tip, i.e.
+by giving the brushes an "angle of lead." An objection to this process
+is that the main flux is thereby weakened owing to the belt of back
+ampere-turns which arises (_v. supra_). A still greater objection is
+that the amount of the angle of lead must be suited to the value of the
+load, the corrective power of copper brushes being very small if the
+reversing E.M.F. is not closely adjusted in proportion to the armature
+current.
+
+On this account metal brushes have been almost entirely superseded by
+carbon moulded into hard blocks. With these, owing to their higher
+specific contact-resistance, a very considerable reversing effect can be
+obtained through the action of unequal current-density, and indeed in
+favourable cases complete sparklessness can be obtained throughout the
+entire range of load of the machine with a fixed position of the
+brushes. Yet if the work which they are called upon to perform exceeds
+certain limits, they tend to become overheated with consequent glowing
+or sparking at their tips, so that, wherever possible, it is advisable
+to reinforce their action by a certain amount of reversing field, the
+brushes being set so that its strength is roughly correct for, say, half
+load.
+
+In the case of dynamos driven by steam-turbines, sparkless commutation
+is especially difficult to obtain owing to the high speed of rotation
+and the very short space of time in which the current has to be
+reversed. Special "reversing poles" then become necessary; these are
+wound with magnetizing coils in series with the main armature current,
+so that the strength of field which they yield is roughly proportional
+to the current which has to be reversed. These again may be combined
+with a "compensating winding" embedded in the pole-faces and carrying
+current in the opposite direction to the armature ampere-turns, so as to
+neutralize the cross effect of the latter and prevent distortion of the
+resultant field.
+
+
+    Heating effects.
+
+  From the moment that a dynamo begins to run with excited field, heat
+  is continuously generated by the passage of the current through the
+  windings of the field-magnet coils and the armature, as well as by the
+  action of hysteresis and eddy currents in the armature and
+  pole-pieces. Whether the source of the heat be in the field-magnet or
+  in the armature, the mass in which it originates will continue to rise
+  in temperature until such a difference of temperature is established
+  between itself and the surrounding air that the rate at which the heat
+  is carried off by radiation, convection and conduction is equal to the
+  rate at which it is being generated. Evidently, then, the temperature
+  which any part of the machine attains after a prolonged run must
+  depend on the extent and effectiveness of the cooling surface from
+  which radiation takes place, upon the presence or absence of any
+  currents of air set up by the rotation of itself or surrounding parts,
+  and upon the presence of neighbouring masses of metal to carry away
+  the heat by conduction. In the field-magnet coils the rate at which
+  heat is being generated is easily determined, since it is equal to the
+  square of the current passing through them multiplied by their
+  resistance. Further, the magnet is usually stationary, and only
+  indirectly affected by draughts of air due to the rotating armature.
+  Hence for machines of a given type and of similar proportions, it is
+  not difficult to decide upon some method of reckoning the cooling
+  surface of the magnet coils S_c, such that the rise of temperature
+  above that of the surrounding air may be predicted from an equation of
+  the form t deg. = kW/S_c, where W = the rate in watts at which heat is
+  generated in the coils, and k is some constant depending upon the
+  exact method of reckoning their cooling surface. As a general rule the
+  cooling surface of a field-coil is reckoned as equal to the exposed
+  outer surface of its wire, the influence of the end flanges being
+  neglected, or only taken into account in the case of very short
+  bobbins wound with a considerable depth of wire. In the case of the
+  rotating armature a similar formula must be constructed, but with the
+  addition of a factor to allow for the increase in the effectiveness of
+  any given cooling surface due to the rotation causing convection
+  currents in the surrounding air. Only experiment can determine the
+  exact effect of this, and even with a given type of armature it is
+  dependent on the number of poles, each of which helps to break up the
+  air-currents, and so to dissipate the heat. For example, in two-pole
+  machines with drum bar-armatures, if the cooling surface be reckoned
+  as equal to the cylindrical exterior plus the area of the two ends,
+  the heating coefficient for a peripheral speed of 1500 ft. per minute
+  is less than half of that for the same armature when at rest. A
+  further difficulty still meets the designer in the correct
+  predetermination of the total loss of watts in an armature before the
+  machine has been tested. It is made up of three separate items,
+  namely, the copper loss in the armature winding, the loss by
+  hysteresis in the iron, and the loss by eddy currents, which again may
+  be divided into those in the armature bars and end-connexions, and
+  those in the core and its end-plates. The two latter items are both
+  dependent upon the speed of the machine; but whereas the hysteresis
+  loss is proportional to the speed for a given density of flux in the
+  armature, the eddy current loss is proportional to the square of the
+  speed, and owing to this difference, the one loss can be separated
+  from the other by testing an armature at varying speeds. Thus for a
+  given rise of temperature, the question of the amount of current which
+  can be taken out of an armature at different speeds depends upon the
+  proportion which the hysteresis and eddy watts bear to the copper
+  loss, and the ratio in which the effectiveness of the cooling surface
+  is altered by the alteration in speed. Experimental data, again, can
+  alone decide upon the amount of eddy currents that may be expected in
+  given armatures, and caution is required in applying the results of
+  one machine to another in which any of the conditions, such as the
+  number of poles, density in the teeth, proportions of slot depth to
+  width, &c., are radically altered.
+
+  It remains to add, that the rise of temperature which may be permitted
+  in any part of a dynamo after a prolonged run is very generally placed
+  at about 70 deg. Fahr. above the surrounding air. Such a limit in ordinary
+  conditions of working leads to a final temperature of about 170 deg.
+  Fahr., beyond which the durability of the insulation of the wires is
+  liable to be injuriously affected. Upon some such basis the output of
+  a dynamo in continuous working is rated, although for short periods
+  of, say, two hours the normal full-load current of a large machine may
+  be exceeded by some 25% without unduly heating the armature.
+
+
+  Uses of continuous current dynamos.
+
+For the electro-deposition of metals or the electrolytic treatment of
+ores a continuous current is a necessity; but, apart from such use, the
+purposes from which the continuous-current dynamo is well adapted are so
+numerous that they cover nearly the whole field of electrical
+engineering, with one important exception. To meet these various uses,
+the pressures for which the machine is designed are of equally wide
+range; for the transmission of power over long distances they may be as
+high as 3000 volts, and for electrolytic work as low as five. Each
+electrolytic bath, with its leads, requires on an average only some four
+or five volts, so that even when several are worked in series the
+voltage of the dynamo seldom exceeds 60. On the other hand, the current
+is large and may amount to as much as from 1000 to 14,000 amperes,
+necessitating the use of two commutators, one at either end of the
+armature, in order to collect the current without excessive heating of
+the sectors and brushes. The field-magnets are invariably shunt-wound,
+in order to avoid reversal of the current through polarization at the
+electrodes of the bath. For incandescent lighting by glow lamps, the
+requirements of small isolated installations and of central stations for
+the distribution of electrical energy over large areas must be
+distinguished. For the lighting of a private house or small factory, the
+dynamo giving from 5 to 100 kilo-watts of output is commonly wound for a
+voltage of 100, and is driven by pulley and belt from a gas, oil or
+steam-engine; or, if approaching the higher limit above mentioned, it is
+often directly coupled to the crank-shaft of the steam-engine. If used
+in conjunction with an accumulator of secondary cells, it is
+shunt-wound, and must give the higher voltage necessary to charge the
+battery; otherwise it is compound-wound, in order to maintain the
+pressure on the lamps constant under all loads within its capacity. The
+compound-wound dynamo is likewise the most usual for the lighting of
+steamships, and is then directly coupled to its steam-engine; its output
+seldom exceeds 100 kilo-watts, at a voltage of 100 or 110. For larger
+installations a voltage of 250 is commonly used, while for
+central-station work, economy in the distributing mains dictates a
+higher voltage, especially in connexion with a three-wire system; the
+larger dynamos may then give 500 volts, and be connected directly across
+the two outer wires. A pair of smaller machines coupled together, and
+each capable of giving 250 volts, are often placed in series across the
+system, with their common junction connected to the middle wire; the one
+which at any time is on the side carrying the smaller current will act
+as a motor and drive the other as a dynamo, so as to balance the system.
+The directly-coupled steam dynamo may be said to have practically
+displaced the belt- or rope-driven sets which were formerly common in
+central stations. The generating units of the central station are
+arranged in progressive sizes, rising from, it may be, 250 or 500
+horse-power up to 750 or 1000, or in large towns to as much as 5000
+horse-power. If for lighting only, they are usually shunt-wound, the
+regulation of the voltage, to keep the pressure constant on the
+distributing system under the gradual changes of load, being effected by
+variable resistances in the shunt circuit of the field-magnets.
+
+Generators used for supplying current to electric tramways are commonly
+wound for 500 volts at no load and are over-compounded, so that the
+voltage rises to 550 volts at the maximum load, and thus compensates for
+the loss of volts over the transmitting lines. For arc lighting it was
+formerly usual to employ a class of dynamo which, from the nature of its
+construction, was called an "open-coil" machine, and which gave a
+unidirectional but pulsating current. Of such machines the Brush and
+Thomson-Houston types were very widely used; their E.M.F. ranged from
+2000 to 3000 volts for working a large number of arcs in series, and by
+means of special regulators their current was maintained constant over a
+wide range of voltage. But as their efficiency was low and they could
+not be applied to any other purpose, they have been largely superseded
+in central stations by closed-coil dynamos or alternators, which can
+also be used for incandescent lighting. In cases where the central
+station is situated at some distance from the district to which the
+electric energy is to be supplied, voltages from 1000 to 2000 are
+employed, and these are transformed down at certain distributing centres
+by continuous-current transformers (see TRANSFORMERS and ELECTRICITY
+SUPPLY). These latter machines are in reality motor-driven dynamos, and
+hence are also called _motor-generators_; the armatures of the motor and
+dynamo are often wound on the same core, with a commutator at either
+end, the one to receive the high-pressure motor current, and the other
+to collect the low-pressure current furnished by the dynamo.
+
+  In all large central stations it is necessary that the dynamos should
+  be capable of being run _in parallel_, so that their outputs may be
+  combined on the same "omnibus bars" and thence distributed to the
+  network of feeders. With simple shunt-wound machines this is easily
+  effected by coupling together terminals of like sign when the voltage
+  of the two or more machines are closely equal. With compound-wound
+  dynamos not only must the external terminals of like sign be coupled
+  together, but the junctions of the brush leads with the series winding
+  must be connected by an "equalizing" lead of low resistance;
+  otherwise, should the E.M.F. of one machine for any reason fall below
+  the voltage of the omnibus bars, there is a danger of its polarity
+  being reversed by a back current from the others with which it is in
+  parallel.
+
+  Owing to the necessary presence in the continuous-current dynamo of
+  the commutator, with its attendant liability to sparking at the
+  brushes, and further, owing to the difficulty of insulating the
+  rotating armature wires, a pressure of 3000 volts has seldom been
+  exceeded in any one continuous-current machine, and has been given
+  above as the limiting voltage of the class. If therefore it is
+  required to work with higher pressures in order to secure economy in
+  the transmitting lines, two or more machines must be coupled _in
+  series_ by connecting together terminals which are of unlike sign.[19]
+  The stress of the total voltage may still fall on the insulation of
+  the winding from the body of the machine; hence for high-voltage
+  transmission of power over very long distances, the continuous-current
+  dynamo in certain points yields in convenience to the alternator. In
+  this there is no commutator, the armature coils may be stationary and
+  can be more thoroughly insulated, while further, if it be thought
+  undesirable to design the machine for the full transmitting voltage,
+  it is easy to wind the armature for a low pressure; this can be
+  subsequently transformed up to a high pressure by means of the
+  alternating-current transformer, which has stationary windings and so
+  high an efficiency that but little loss arises from its use. With
+  these remarks, the transition may be made to the fuller discussion of
+  the alternator.
+
+
+_Alternators._
+
+  Frequency.
+
+The frequency employed in alternating-current systems for distributing
+power and light varies between such wide limits as 25 and 133; yet in
+recent times the tendency has been towards standard frequencies of 25,
+50 and 100 as a maximum. High frequencies involve more copper in the
+magnet coils, owing to the greater number of poles, and a greater loss
+of power in their excitation, but the alternator as a whole is somewhat
+lighter, and the transformers are cheaper. On the other hand, high
+frequency may cause prejudicial effects, due to the inductance and
+capacity of the distributing lines; and in asynchronous motors used on
+polyphase systems the increased number of poles necessary to obtain
+reasonable speeds reduces their efficiency, and is otherwise
+disadvantageous, especially for small horse-powers. A frequency lower
+than 40 is, however, not permissible where arc lighting is to form any
+considerable portion of the work and is to be effected by the
+alternating current without rectification, since below this value the
+eye can detect the periodic alteration in the light as the carbons
+alternately cool and become heated. Thus for combined lighting and power
+50 or 60 are the most usual frequencies; but if the system is designed
+solely or chiefly for the distribution of power, a still lower frequency
+is preferable. On this account 25 was selected by the engineers for the
+Niagara Falls power transmission, after careful consideration of the
+problem, and this frequency has since been widely adopted in similar
+cases.
+
+
+  Alternator construction.
+
+The most usual type of heteropolar alternator has an internal rotating
+field-magnet system, and an external stationary armature, as in fig. 10.
+The coils of the armature, which must for high voltages be heavily
+insulated, are then not subjected to the additional stresses due to
+centrifugal force; and further, the collecting rings which must be
+attached to the rotating portion need only transmit the exciting current
+at a low voltage.
+
+[Illustration: FIG. 36.]
+
+The homopolar machine possesses the advantages that only a single
+exciting coil is required, whatever the number of polar projections, and
+that both the armature and field-magnet coils may be stationary. From
+fig. 8 it will be seen that it is not essential that the exciting coil
+should revolve with the internal magnet, but it may be supported from
+the external stationary armature while still embracing the central part
+of the rotor. The E.M.F. is set up in the armature coils through the
+periodic variation of the flux through them as the iron projections
+sweep past, and these latter may be likened to a number of "keepers,"
+which complete the magnetic circuit. From the action of the rotating
+iron masses they may also be considered as the inducing elements or
+"inductors," and the homopolar machine is thence also known as the
+"inductor alternator." If the end of the rotor marked S in fig. 8 is
+split up into a number of S polar projections similar to the N poles, a
+second set of armature coils may be arranged opposite to them, and we
+obtain an inductor alternator with double armature. Or the polar
+projections at the two ends may be staggered, and a single armature
+winding be passed straight through the armature, as in fig. 36, which
+shows at the side the appearance of the revolving inductor with its
+crown of polar projections in one ring opposite to the gaps between the
+polar projections of the other ring. But in spite of its advantage of
+the single stationary exciting coil, the inductor alternator has such a
+high degree of leakage, and the effect of armature reaction is so
+detrimental in it, that the type has been gradually abandoned, and a
+return has been almost universally made to the heteropolar alternator
+with internal poles radiating outwards from a circular yoke-ring. The
+construction of a typical machine of this class is illustrated in fig.
+37.
+
+[Illustration: FIG. 37.]
+
+Since the field-magnet coils rotate, they must be carefully designed to
+withstand centrifugal force, and are best composed of flat copper strip
+wound on edge with thin insulation between adjacent layers. The coil is
+secured by the edges of the pole-shoes which overhang the pole and
+tightly compress the coil against the yoke-ring; the only effect from
+centrifugal force is then to compress still further the flat turns of
+copper against the pole-shoes without deformation. The poles are either
+of cast steel of circular or oblong section, bolted to the rim of the
+yoke-ring, or are built up of thin laminations of sheet steel. When the
+peripheral speed is very high, the yoke-ring will be of cast steel or
+may itself be built up of sheet steel laminations, this material being
+reliable and easily tested to ensure its sound mechanical strength. If
+the armature slots are open, the pole-pieces will in any case be
+laminated to reduce the eddy currents set up by the variation of the
+flux-density.
+
+Owing to the great number of poles[20] of the alternator when driven by
+a reciprocating steam-engine, the diameter of its rotor is usually
+larger and its length less than in the continuous-current dynamo of
+corresponding output. The support of the armature core when of large
+diameter is therefore a more difficult problem, since, apart from any
+magnetic strains to which it may be subjected, its own weight tends to
+deform it. The segmental core-disks are usually secured to the internal
+circumference of a circular cast iron frame; the latter has a box
+section of considerable radial depth to give stiffness to it, and the
+disks are tightly clamped between internal flanges, one being a fixed
+part of the frame and the other loose, with transverse bolts passing
+right through from side to side (fig. 37). In order to lessen the weight
+of the structure and its expense in material, the cast iron frame has in
+some cases been entirely dispensed with, and braced tie-rods have been
+used to render the effective iron of the armature core-disks
+self-supporting.
+
+[Illustration: FIG. 38.]
+
+Owing to the high speed of the turbo-alternator, its rotor calls for the
+utmost care in its design to withstand the effect of centrifugal force
+without any shifting of the exciting coils, and to secure a perfect
+balance.
+
+The appearance of the armature of a typical three-phase alternator is
+illustrated in fig. 38, which shows a portion of the lower half after
+removal of the field-magnet.
+
+With open slots the coils, after being wound on formers to the required
+shape, are thoroughly impregnated with insulating compound, dried, and
+after a further wrapping with several layers of insulating material,
+finally pressed into the slots together with a sheet of leatheroid or
+flexible micanite. The end-connexions of each group of coils of one
+phase project straight out from the slots or are bent upwards
+alternately with those of the other phases, so that they may clear one
+another (fig. 37). A wooden wedge driven into a groove at the top of
+each slot is often used to lock the coil in place. With slots nearly
+closed at the top, the coils are formed by hand by threading the wire
+through tubes of micanite or specially prepared paper lining the slots;
+or with single-turn loops, stout bars of copper of [U]-shape can be
+driven through the slots and closed by soldered connexions at the other
+end.
+
+
+    Shape of E.M.F. curve.
+
+  The first experimental determination of the shape of the E.M.F. curve
+  of an alternator was made by J. Joubert in 1880. A revolving
+  contact-maker charged a condenser with the E.M.F. produced by the
+  armature at a particular instant during each period. The condenser was
+  discharged through a ballistic galvanometer, and from the measured
+  throw the instantaneous E.M.F. could be deduced. The contact-maker was
+  then shifted through a small angle, and the instantaneous E.M.F. at
+  the new position corresponding to a different moment in the period was
+  measured; this process was repeated until the E.M.F. curve for a
+  complete period could be traced. Various modifications of the same
+  principle have since been used, and a form of "oscillograph" (q.v.)
+  has been perfected which is well adapted for the purpose of tracing
+  the curves both of E.M.F. and of current. The machine on which Joubert
+  carried out his experiments was a Siemens disk alternator having no
+  iron in its armature, and it was found that the curve of E.M.F. was
+  practically identical with a sine curve. The same law has also been
+  found to hold true for a smooth-core ring or drum armature, but the
+  presence of the iron core enables the armature current to produce
+  greater distorting effect, so that the curves under load may vary
+  considerably from their shape at no load. In toothed armatures, the
+  broken surface of the core, and the still greater reaction from the
+  armature current, may produce wide variations from the sine law, the
+  general tendency being to give the E.M.F. curve a more peaked form.
+  The great convenience of the assumption that the E.M.F. obeys the sine
+  law has led to its being very commonly used as the basis for the
+  mathematical analysis of alternator problems; but any deductions made
+  from this premiss require to be applied with caution if they are
+  likely to be modified by a different shape of the curve. Further, the
+  same alternator will give widely different curves even of E.M.F., and
+  still more so of current, according to the nature of the external
+  circuit to which it is connected. As will be explained later, the
+  phase of the current relatively to the E.M.F. depends not only on the
+  inductance of the alternator itself, but also upon the inductance and
+  capacity of the external circuit, so that the same current will
+  produce different effects according to the amount by which it lags or
+  leads. The question as to the relative advantages of differently
+  shaped E.M.F. curves has led to much discussion, but can only be
+  answered by reference to the nature of the work that the alternator
+  has to do--i.e. whether it be arc lighting, motor driving, or
+  incandescent lighting through transformers. The shape of the E.M.F.
+  curve is, however, of great importance in one respect, since upon it
+  depends the ratio of the maximum instantaneous E.M.F. to the effective
+  value, and the insulation of the entire circuit, both external and
+  internal, must be capable of withstanding the maximum E.M.F. While the
+  maximum value of the sine curve is [root]2 or 1.414 times the
+  effective value, the maximum value of a [Lambda] curve is 1.732 times
+  the effective value, so that for the same effective E.M.F. the
+  armature wires must not only be more heavily insulated than in the
+  continuous-current dynamo, but also the more peaked the curve the
+  better must be the insulation.
+
+
+    Excitation.
+
+  Since an alternating current cannot be used for exciting the
+  field-magnet, recourse must be had to some source of a direct current.
+  This is usually obtained from a small auxiliary continuous-current
+  dynamo, called an _exciter_, which may be an entirely separate
+  machine, separately driven and used for exciting several alternators,
+  or may be driven from the alternator itself; in the latter case the
+  armature of the exciter is often coupled directly to the rotating
+  shaft of the alternator, while its field-magnet is attached to the
+  bed-plate. Although separate excitation is the more usual method, the
+  alternator can also be made self-exciting if a part or the whole of
+  the alternating current is "rectified," and thus converted into a
+  direct current.
+
+
+    Quarter-phase alternators.
+
+  The general idea of the polyphase alternator giving two or more
+  E.M.F.'s of the same frequency, but displaced in phase, has been
+  already described. The several phases may be entirely independent, and
+  such was the case with the early polyphase machines of Gramme, who
+  used four independent circuits, and also in the large two-phase
+  alternators designed by J.E.H. Gordon in 1883. If the phases are thus
+  entirely separate, each requires two collector rings and two wires to
+  its external circuit, i.e. four in all for two-phase and six for
+  three-phase machines. The only advantage of the polyphase machine as
+  thus used is that the whole of the surface of the armature core may be
+  efficiently covered with winding, and the output of the alternator for
+  a given size be thereby increased. It is, however, also possible so to
+  interlink the several circuits of the armature that the necessary
+  number of transmitting lines to the external circuits may be reduced,
+  and also the weight of copper in them for a given loss in the
+  transmission.[21] The condition which obviously must be fulfilled,
+  for such interlinking of the phases to be possible, is that in the
+  lines which are to meet at any common junction the algebraic sum of
+  the instantaneous currents, reckoned as positive if away from such
+  junction and as negative if towards it, must be zero. Thus if the
+  phases be diagrammatically represented by the relative angular
+  position of the coils in fig. 39, the current in the coils A and B
+  differs in phase from the current in the coils C and D by a quarter of
+  a period or 90 deg.; hence if the two wires b and d be replaced by the
+  single wire bd, this third wire will serve as a common path for the
+  currents of the two phases either outwards or on their return. At any
+  instant the value of the current in the third wire must be the vector
+  sum of the two currents in the other wires, and if the shape of the
+  curves of instantaneous E.M.F. and current are identical, and are
+  assumed to be sinusoidal, the effective value of the current in the
+  third wire will be the vector sum of the effective values of the
+  currents in the other wires; in other words, if the system is
+  balanced, the effective current in the third wire is [root]2, or 1.414
+  times the current in either of the two outer wires. Since the currents
+  of the two phases do not reach their maximum values at the same time,
+  the sectional area of the third wire need not be twice that of the
+  others; in order to secure maximum efficiency by employing the same
+  current density in all three wires, it need only be 40% greater than
+  that of either of the outer wires. The effective voltage between the
+  external leads may in the same way be calculated by a vector diagram,
+  and with the above _star connexion_ the voltage between the outer pair
+  of wires a and c is [root]2, or 1.414 times the voltage between either
+  of the outer wires and the common wire bd. Next, if the four coils are
+  joined up into a continuous helix, just as in the winding of a
+  continuous-current machine, four wires may be attached to equidistant
+  points at the opposite ends of two diameters at right angles to each
+  other (fig. 40). Such a method is known as the _mesh connexion_, and
+  gives a perfectly symmetrical four-phase system of distribution. Four
+  collecting rings are necessary if the armature rotates, and there is
+  no saving in copper in the transmitting lines; but the importance of
+  the arrangement lies in its use in connexion with rotary converters,
+  in which it is necessary that the winding of the armature should form
+  a closed circuit. If e = the effective voltage of one phase A, the
+  voltage between any pair of adjacent lines in the diagram is e, and
+  between m and o or n and p is e [root]2. The current in any line is
+  the resultant of the currents in the two phases connected to it, and
+  its effective value is c [root]2, where c is the current of one phase.
+
+  [Illustration: FIG. 39.]
+
+  [Illustration: FIG. 40.]
+
+  [Illustration: FIG. 41.]
+
+
+    Three-phase alternators.
+
+  When we pass to machines giving three phases differing by 120 deg., the
+  same methods of star and mesh connexion find their analogies. If the
+  current in coil A (fig. 41) is flowing away from the centre, and has
+  its maximum value, the currents in coils B and C are flowing towards
+  the centre, and are each of half the magnitude of the current in A;
+  the algebraic sum of the currents is therefore zero, and this will
+  also be the case for all other instants. Hence the three coils can be
+  united together at the centre, and three external wires are alone
+  required. In this star or "Y" connexion, if e be the effective voltage
+  of each phase, or the voltage between any one of the three collecting
+  rings and the common connexion, the volts between any pair of
+  transmitting lines will be E = e [root]3 (fig. 41); if the load be
+  balanced, the effective current C in each of the three lines will be
+  equal, and the total output in watts will be W = 3Ce = 3CE/[root]3 =
+  1.732 EC, or 1.732 times the product of the effective voltage between
+  the lines and the current in any single line. Next, if the three coils
+  are closed upon themselves in a mesh or _delta_ fashion (fig. 42), the
+  three transmitting wires may be connected to the junctions of the
+  coils (by means of collecting rings if the armature rotates). The
+  voltage E between any pair of wires is evidently that generated by
+  one phase, and the current in a line wire is the resultant of that in
+  two adjacent phases; or in a balanced system, if c be the current in
+  each phase, the current in the line wire beyond a collecting ring is C
+  = c [root]3, hence the watts are W = 3cE = 3CE/[root]3 = 1.732 EC, as
+  before. Thus any three-phase winding may be changed over from the star
+  to the delta connexion, and will then give 1.732 times as much
+  current, but only 1/1.732 times the voltage, so that the output
+  remains the same.
+
+  [Illustration: FIG. 42.]
+
+
+    Armature reaction in alternators
+
+  The "armature reaction" of the alternator, when the term is used in
+  its widest sense to cover all the effects of the alternating current
+  in the armature as linked with a magnetic circuit or circuits, may be
+  divided into three items which are different in their origin and
+  consequences. In the first place the armature current produces a
+  self-induced flux in local circuits independent of the main magnetic
+  circuit, as e.g. linked with the ends of the coils as they project
+  outwards from the armature core; such lines may be called "secondary
+  leakage," of which the characteristic feature is that its amount is
+  independent of the position of the coils relatively to the poles. The
+  alternations of this flux give rise to an inductive voltage lagging
+  90 deg. behind the phase of the current, and this leakage or reactance
+  voltage must be directly counterbalanced electrically by an equal
+  component in the opposite sense in the voltage from the main field.
+  The second and third elements are more immediately magnetic and are
+  entirely dependent upon the position of the coils in relation to the
+  poles and in relation to the phase of the current which they then
+  carry. When the side of a drum coil is immediately under the centre of
+  a pole, its ampere-turns are cross-magnetizing, i.e. produce a
+  distortion of the main flux, displacing its maximum density to one or
+  other edge of the pole. When the coil-side is midway between the poles
+  and the axes of coil and pole coincide, the coil stands exactly
+  opposite to the pole and embraces the same magnetic circuit as the
+  field-magnet coils; its turns are therefore directly magnetizing,
+  either weakening or strengthening the main flux according to the
+  direction of the current. In intermediate positions the ampere-turns
+  of the coil gradually pass from cross to direct and vice versa. When
+  the instantaneous values of either the cross or direct magnetizing
+  effect are integrated over a period and averaged, due account being
+  taken of the number of slots per coil-side and of the different phases
+  of the currents in the polyphase machine, expressions are obtained for
+  the equivalent cross and direct ampere-turns of the armature as acting
+  upon a pair of poles. For a given winding and current, the determining
+  factor in either the one or the other is found to be the relative
+  phase angle between the axis of a coil in its position when carrying
+  the maximum current and the centre of a pole, the transverse reaction
+  being proportional to the cosine of this angle, and the direct
+  reaction to its sine. If the external circuit is inductive, the
+  maximum value of the current lags behind the E.M.F. and so behind the
+  centre of the pole; such a negative angle of lag causes the direct
+  magnetizing turns to become back turns, directly weakening the main
+  field and lowering the terminal voltage. Thus, just as in the
+  continuous-current dynamo, for a given voltage under load the
+  excitation between the pole-pieces X_p must not only supply the net
+  excitation required over the air-gaps, armature core and teeth, but
+  must also balance the back ampere-turns X_b of the armature.
+
+  Evidently therefore the characteristic curve connecting armature
+  current and terminal volts will with a constant exciting current
+  depend on the nature of the load, whether inductive or non-inductive,
+  and upon the amount of inductance already possessed by the armature
+  itself. With an inductive load it will fall more rapidly from its
+  initial maximum value, or, conversely, if the initial voltage is to be
+  maintained under an increasing load, the exciting current will have to
+  be increased more than if the load were non-inductive. In practical
+  working many disadvantages result from a rapid drop of the terminal
+  E.M.F. under increasing load, so that between no load and full load
+  the variation in terminal voltage with constant excitation should not
+  exceed 15%. Thus the output of an alternator is limited either by its
+  heating or by its armature reaction, just as is the output of a
+  continuous-current dynamo; in the case of the alternator, however, the
+  limit set by armature reaction is not due to any sparking at the
+  brushes, but to the drop in terminal voltage as the current is
+  increased, and the consequent difficulty in maintaining a constant
+  potential on the external circuit.
+
+
+    The coupling of alternators.
+
+  The joint operation of several alternators so that their outputs may
+  be delivered into the same external circuit is sharply distinguished
+  from the corresponding problem in continuous-current dynamos by the
+  necessary condition that they must be in synchronism, i.e. not only
+  must they be so driven that their frequency is the same, but their
+  E.M.F.'s must be in phase or, as it is also expressed, the machines
+  must be in step. Although in practice it is impossible to run two
+  alternators in series unless they are rigidly coupled together--which
+  virtually reduces them to one machine--two or more machines can be run
+  in parallel, as was first described by H. Wilde in 1868 and
+  subsequently redemonstrated by J. Hopkinson and W.G. Adams in 1884.
+  Their E.M.F.'s should be as nearly as possible in synchronism, but,
+  as contrasted with series connexion, parallel coupling gives them a
+  certain power of recovery if they fall out of step, or are not in
+  exact synchronism when thrown into parallel. In such circumstances a
+  synchronizing current passes between the two machines, due to the
+  difference in their instantaneous pressures; and as this current
+  agrees in phase more nearly with the leading than with the lagging
+  machine, the former machine does work as a generator on the latter as
+  a motor. Hence the lagging machine is accelerated and the leading
+  machine is retarded, until their frequencies and phase are again the
+  same.
+
+
+  Uses of alternators.
+
+The chief use of the alternator has already been alluded to. Since it
+can be employed to produce very high pressures either directly or
+through the medium of transformers, it is specially adapted to the
+electrical transmission of energy over long distances.[22] In the early
+days of electric lighting, the alternate-current system was adopted for
+a great number of central stations; the machines, designed to give a
+pressure of 2000 volts, supplied transformers which were situated at
+considerable distances and spread over large areas, without an undue
+amount of copper in the transmitting lines. While there was later a
+tendency to return to the continuous current for central stations, owing
+to the introduction of better means for economizing the weight of copper
+in the mains, the alternating current again came into favour, as
+rendering it possible to place the central station in some convenient
+site far away from the district which it was to serve. The pioneer
+central station in this direction was the Deptford station of the London
+Electric Supply Corporation, which furnished current to the heart of
+London from a distance of 7 m. In this case, however, the alternators
+were single-phase and gave the high pressure of 10,000 volts
+immediately, while more recently the tendency has been to employ step-up
+transformers and a polyphase system. The advantage of the latter is that
+the current, after reaching the distant sub-stations, can be dealt with
+by rotary converters, through which it is transformed into a continuous
+current. The alternator is also used for welding, smelting in electric
+furnaces, and other metallurgical processes where heating effects are
+alone required; the large currents needed therein can be produced
+without the disadvantage of the commutator, and, if necessary,
+transformers can be interposed to lower the voltage and still further
+increase the current. The alternating system can thus meet very various
+needs, and its great recommendation may be said to lie in the
+flexibility with which it can supply electrical energy through
+transformers at any potential, or through rotary converters in
+continuous-current form.
+
+  AUTHORITIES.--For the further study of the dynamo, the following may
+  be consulted, in addition to the references already given:--
+
+  _General_: S.P. Thompson, _Dynamo-Electric
+  Machinery--Continuous-Current Machines_ (1904), _Alternating-Current
+  Machinery_ (1905, London); G. Kapp, _Dynamos, Alternators and
+  Transformers_ (London, 1893); _Id., Electric Transmission of Energy_
+  (London, 1894); Id., _Dynamo Construction; Electrical and Mechanical_
+  (London, 1899); H.F. Parshall and H.M. Hobart, _Electric Generators_
+  (London, 1900); C.C. Hawkins and F. Wallis, _The Dynamo_ (London,
+  1903); E. Arnold, _Konstruktionstafeln fuer den Dynamobau_ (Stuttgart,
+  1902); C.P. Steinmetz, _Elements of Electrical Engineering_ (New York,
+  1901).
+
+  _Continuous-Current Dynamos_: J. Fischer-Hinnen, _Continuous-Current
+  Dynamos_ (London, 1899); E. Arnold, _Die Gleichstrommaschine_ (Berlin,
+  1902); F. Niethammer, _Berechnung und Konstruktion der
+  Gleichstrommaschinen und Gleichstrommotoren_ (Stuttgart, 1904).
+
+  _Alternators_: D.C. Jackson and J.P. Jackson, _Alternating Currents
+  and Alternating Current Machinery_ (New York, 1903); J.A. Fleming,
+  _The Alternate Current Transformer_ (London, 1899); C.P. Steinmetz,
+  _Alternating Current Phenomena_ (New York, 1900); E. Arnold, _Die
+  Wechselstromtechnik_ (Berlin, 1904); S.P. Thompson, _Polyphase
+  Electric Currents_ (London, 1900); A. Stewart, _Modern Polyphase
+  Machinery_ (London, 1906); M. Oudin, _Standard Polyphase Apparatus and
+  Systems_ (New York, 1904).     (C. C. H.)
+
+
+FOOTNOTES:
+
+  [1] _Experimental Researches in Electricity_, series ii. Sec. 6, pars.
+    256, 259-260, and series xxviii. Sec. 34.
+
+  [2] _Ibid._ series i. Sec. 4, pars. 84-90.
+
+  [3] "On the Physical Lines of Magnetic Force," _Phil. Mag._, June
+    1852.
+
+  [4] Faraday, _Exp. Res._ series xxviii. Sec. 34, pars. 3104, 3114-3115.
+
+  [5] _Id._, ib. series i. Sec. 4, pars. 114-119.
+
+  [6] _Id._, ib. series ii. Sec. 6, pars. 211, 213; series xxviii. Sec. 34,
+    par. 3152.
+
+  [7] Invented by Nikola Tesla (_Elec. Eng._ vol. xiii. p. 83. Cf.
+    Brit. Pat. Spec. Nos. 2801 and 2812, 1894). Several early inventors,
+    e.g. Salvatore dal Negro in 1832 (_Phil. Mag._ third series, vol. i.
+    p. 45), adopted reciprocating or oscillatory motion, and this was
+    again tried by Edison in 1878.
+
+  [8] The advantage to be obtained by making the poles closely embrace
+    the armature core was first realized by Dr Werner von Siemens in his
+    "shuttle-wound" armature (Brit. Pat. No. 2107, 1856).
+
+  [9] _Nuovo Cimento_ (1865), 19, 378.
+
+  [10] Brit. Pat. No. 1668 (1870); _Comptes rendus_ (1871), 73, 175.
+
+  [11] _Ann. Chim. Phys._ l. 322.
+
+  [12] Ibid. li. 76. Since in H. Pixii's machine the armature was
+    stationary, while both magnet and commutator rotated, four brushes
+    were used, and the arrangement was not so simple as the split-ring
+    described above, although the result was the same. J. Saxton's
+    machine (1833) and E.M. Clarke's machine (1835, see Sturgeon's
+    _Annals of Electricity_, i. 145) were similar to one another in that
+    a unidirected current was obtained by utilizing every alternate
+    half-wave of E.M.F., but the former still employed mercury collecting
+    cups, while the latter employed metal brushes. W. Sturgeon in 1835
+    followed Pixii in utilizing the entire wave of E.M.F., and abandoned
+    the mercury cups in favour of metal brushes pressing on four
+    semicircular disks (_Scientific Researches_, p. 252). The simple
+    split-ring is described by Sir C. Wheatstone and Sir W.F. Cooke in
+    their Patent No. 8345 (1840).
+
+  [13] By the "leading" side of the tooth or of an armature coil or
+    sector is to be understood that side which first enters under a pole
+    after passing through the interpolar gap, and the edge of the pole
+    under which it enters is here termed the "leading" edge as opposed to
+    the "trailing" edge or corner from under which a tooth or coil
+    emerges into the gap between the poles; cf. fig. 30, where the
+    leading and trailing pole-corners are marked ll and tt.
+
+  [14] Such was the arrangement of Wheatstone's machine (Brit. Pat. No.
+    9022) of 1841, which was the first to give a more nearly "continuous"
+    current, the number of sections and split-rings being five.
+
+  [15] Its development from the split-ring was due to Pacinotti and
+    Gramme (Brit. Pat. No. 1668, 1870) in connexion with their ring
+    armatures.
+
+  [16] And extended by G. Kapp, "On Modern Continuous-Current
+    Dynamo-Electric Machines," _Proc. Inst. C.E._ vol. lxxxiii. p. 136.
+
+  [17] Drs J. and E. Hopkinson, "Dynamo-Electric Machinery," Phil.
+    Trans., May 6, 1886; this was further expanded in a second paper on
+    "Dynamo-Electric Machinery," _Proc. Roy. Soc._, Feb. 15, 1892, and
+    both are reprinted in _Original Papers on Dynamo-Machinery and Allied
+    Subjects_.
+
+  [18] _Exp. Res._, series i. Sec. 4, par. 111. In 1845 Wheatstone and
+    Cooke patented the use of "voltaic" magnets in place of permanent
+    magnets (No. 10,655).
+
+  [19] Between Moutiers and Lyons, a distance of 115 m., energy is
+    transmitted on the Thury direct-current system at a maximum pressure
+    of 60,000 volts. Four groups of machines in series are employed, each
+    group consisting of four machines in series; the rated output of each
+    component machine is 75 amperes at 3900 volts or 400 h.p. A water
+    turbine drives two pairs of such machines through an insulating
+    coupling, and the sub-base of each pair of machines is separately
+    insulated from earth, the foundation being also of special insulating
+    materials.
+
+  [20] For experiments on high-frequency currents, Nikola Tesla
+    constructed an alternator having 384 poles and giving a frequency of
+    about 10,000 (_Journ. Inst. Elec. Eng._ 1892, 21, p. 82). The
+    opposite extreme is found in alternators directly coupled to the
+    Parsons steam-turbine, in which, with a speed of 3000 revs. per min.,
+    only two poles are required to give a frequency of 50. By a
+    combination of a Parsons steam-turbine running at 12,000 revs. per
+    min. with an alternator of 140 poles a frequency of 14,000 has been
+    obtained (_Engineering_, 25th of August 1899). For description of an
+    experimental machine for 10,000 cycles per second when running at
+    3000 revs. per min., see _Trans. Amer. Inst. Elect. Eng._ vol. xxiii.
+    p. 417.
+
+  [21] As in the historical transmission of energy from Lauffen to
+    Frankfort (1891).
+
+  [22] In the pioneer three-phase transmission between Laufen and
+    Frankfort (_Electrician_, vol. xxvi. p. 637, and xxvii. p. 548), the
+    three-phase current was transformed up from about 55 to 8500 volts,
+    the distance being 110 m. A large number of installations driven by
+    water power are now at work, in which energy is transmitted on the
+    alternating-current system over distances of about 100 m. at
+    pressures ranging from 20,000 to 67,000 volts.
+
+
+
+
+DYNAMOMETER (Gr. [Greek: dynamis], strength, and [Greek: metron], a
+measure), an instrument for measuring force exerted by men, animals and
+machines. The name has been applied generally to all kinds of
+instruments used in the measurement of a force, as for example electric
+dynamometers, but the term specially denotes apparatus used in connexion
+with the measurement of work, or in the measurement of the horse-power
+of engines and motors. If P represent the average value of the component
+of a force in the direction of the displacement, s, of its point of
+application, the product Ps measures the work done during the
+displacement. When the force acts on a body free to turn about a fixed
+axis only, it is convenient to express the work done by the transformed
+product T[theta], where T is the average turning moment or torque acting
+to produce the displacement [theta] radians. The apparatus used to
+measure P or T is the dynamometer. The factors s or [theta] are observed
+independently. Apparatus is added to some dynamometers by means of which
+a curve showing the variations of P on a distance base is drawn
+automatically, the area of the diagram representing the work done; with
+others, integrating apparatus is combined, from which the work done
+during a given interval may be read off directly. It is convenient to
+distinguish between absorption and transmission dynamometers. In the
+first kind the work done is converted into heat; in the second it is
+transmitted, after measurement, for use.
+
+  _Absorption Dynamometers._--Baron Prony's dynamometer (_Ann. Chim.
+  Phys._ 1821, vol. 19), which has been modified in various ways,
+  consists in its original form of two symmetrically shaped timber beams
+  clamped to the engine-shaft. When these are held from turning, their
+  frictional resistance may be adjusted by means of nuts on the screwed
+  bolts which hold them together until the shaft revolves at a given
+  speed. To promote smoothness of action, the rubbing surfaces are
+  lubricated. A weight is moved along the arm of one of the beams until
+  it just keeps the brake steady midway between the stops which must be
+  provided to hold it when the weight fails to do so. The general theory
+  of this kind of brake is as follows:-Let F be the whole frictional
+  resistance, r the common radius of the rubbing surfaces, W the force
+  which holds the brake from turning and whose line of action is at a
+  perpendicular distance R from the axis of the shaft, N the revolutions
+  of the shaft per minute, [omega] its angular velocity in radians per
+  second; then, assuming that the adjustments are made so that the
+  engine runs steadily at a uniform speed, and that the brake is held
+  still, clear of the stops and without oscillation, by W, the torque T
+  exerted by the engine is equal to the frictional torque Fr acting at
+  the brake surfaces, and this is measured by the statical moment of the
+  weight W about the axis of revolution; that is--
+
+    T = Fr = WR.  (1)
+
+  Hence WR measures the torque T.
+
+  If more than one force be applied to hold the brake from turning, Fr,
+  and therefore T, are measured by the algebraical sum of their
+  individual moments with respect to the axis. If the brake is not
+  balanced, its moment about the axis must be included. Therefore, quite
+  generally,
+
+    T = [Sigma]WR.  (2)
+
+  The factor [theta] of the product T[theta] is found by means of a
+  revolution counter. The power of a motor is measured by the rate at
+  which it works, and this is expressed by T[omega] = T2[pi]N/60 in
+  foot-pounds per second, or T2[pi]N/33,000 in horse-power units. The
+  latter is commonly referred to as the "brake horse-power." The
+  maintenance of the conditions of steadiness implied in equation (1)
+  depends upon the constancy of F, and therefore of the coefficient of
+  friction  mu between the rubbing surfaces. The heating at the surfaces,
+  the variations in their smoothness, and the variations of the
+  lubrication make [mu] continuously variable, and necessitate frequent
+  adjustment of W or of the nuts. J.V. Poncelet (1788-1867) invented a
+  form of Prony brake which automatically adjusted its grip as [mu]
+  changed, thereby maintaining F constant.
+
+  The principle of the compensating brake devised by J.G. Appold
+  (1800-1865) is shown in fig. 1. A flexible steel band, lined with wood
+  blocks, is gripped on the motor fly-wheel or pulley by a screw A,
+  which, together with W, is adjusted to hold the brake steady.
+  Compensation is effected by the lever L inserted at B. This has a
+  slotted end, engaged by a pin P fixed to the framing, and it will be
+  seen that its action is to slacken the band if the load tends to rise
+  and to tighten it in the contrary case. The external forces holding
+  the brake from turning are W, distant R from the axis, and the
+  reaction, W1 say, of the lever against the fixed pin P, distant R1
+  from the axis. The moment of W1 may be positive or negative. The
+  torque T at any instant of steady running is therefore {WR +- W1R1}.
+
+  [Illustration: FIG. 1.]
+
+  Lord Kelvin patented a brake in 1858 (fig. 2) consisting of a rope or
+  cord wrapped round the circumference of a rotating wheel, to one end
+  of which is applied a regulated force, the other end being fixed to a
+  spring balance. The ropes are spaced laterally by the blocks B, B, B,
+  B, which also serve to prevent them from slipping sideways. When the
+  wheel is turning in the direction indicated, the forces holding the
+  band still are W, and p, the observed pull on the spring balance. Both
+  these forces usually act at the same radius R, the distance from the
+  axis to the centre line of the rope, in which case the torque T is (W
+  - p)R, and consequently the brake horse-power is
+
+    (W - p)R x 2[pi]N
+    -----------------.
+          33,000
+
+  When  mu changes the weight W rises or falls against the action of the
+  spring balance until a stable condition of running is obtained. The
+  ratio {W/p} is given by e^{ mu[theta]}, where e = 2.718;  mu is the
+  coefficient of friction and [theta] the angle, measured in radians,
+  subtended by the arc of contact between the rope and the wheel. In
+  fig. 2 [theta] = 2[pi]. The ratio W/p increases very rapidly as
+  [theta] is increased, and therefore, by making [theta] sufficiently
+  large, p may conveniently be made a small fraction of W, thereby
+  rendering errors of observation of the spring balance negligible. Thus
+  this kind of brake, though cheap to make, is, when [theta] is large
+  enough, an exceedingly accurate measuring instrument, readily applied
+  and easily controlled. It has come into very general use in recent
+  years, and has practically superseded the older forms of block brakes.
+
+  [Illustration: FIG. 2.]
+
+  It is sometimes necessary to use water to keep the brake wheel cool.
+  Engines specially designed for testing are usually provided with a
+  brake wheel having a trough-shaped rim. Water trickles continuously
+  into the trough, and the centrifugal action holds it as an inside
+  lining against the rim, where it slowly evaporates.
+
+  Fig. 3 shows a band-brake invented by Professor James Thomson,
+  suitable for testing motors exerting a constant torque (see
+  _Engineering_, 22nd October 1880). To maintain e^{ mu[theta]} constant,
+  compensation for variation of [mu] is made by inversely varying
+  [theta]. A and B are fast and loose pulleys, and the brake band is
+  placed partly over the one and partly over the other. Weights W and w
+  are adjusted to the torque. The band turns with the fast pulley if
+  [mu] increase, thereby slightly turning the loose pulley, otherwise at
+  rest, until [theta] is adjusted to the new value of [mu]. This form of
+  brake was also invented independently by J.A.M.L. Carpentier, and the
+  principle has been used in the Raffard brake. A self-compensating
+  brake of another kind, by Marcel Deprez, was described with
+  Carpentier's in 1880 (_Bulletin de la societe d'encouragement_,
+  Paris). W.E. Ayrton and J. Perry used a band or rope brake in which
+  compensation is effected by the pulley drawing in or letting out a
+  part of the band or rope which has been roughened or in which a knot
+  has been tied.
+
+  In an effective water-brake invented by W. Froude (see _Proc. Inst. M.
+  E._ 1877), two similar castings, A and B, each consisting of a boss
+  and circumferential annular channel, are placed face to face on a
+  shaft, to which B is keyed, A being free (fig. 4). A ring tube of
+  elliptical section is thus formed. Each channel is divided into a
+  series of pockets by equally spaced vanes inclined at 45 deg.. When A is
+  held still, and B rotated, centrifugal action sets up vortex currents
+  in the water in the pockets; thus a continuous circulation is caused
+  between B and A, and the consequent changes of momentum give rise to
+  oblique reactions. The moments of the components of these actions and
+  reactions in a plane to which the axis of rotation is at right angles
+  are the two aspects of the torque acting, and therefore the torque
+  acting on B through the shaft is measured by the torque required to
+  hold A still. Froude constructed a brake to take up 2000 H.P. at 90
+  revs. per min. by duplicating this apparatus. This replaced the
+  propeller of the ship whose engines were to be tested, and the outer
+  casing was held from turning by a suitable arrangement of levers
+  carried to weighing apparatus conveniently disposed on the wharf. The
+  torque corresponding to 2000 H.P. at 90 revs. per min. is 116,772
+  foot-pounds, and a brake 5 ft. in diameter gave this resistance. Thin
+  metal sluices were arranged to slide between the wheel and casing, and
+  by their means the range of action could be varied from 300 H.P. at
+  120 revs. per min. to the maximum.
+
+  [Illustration: FIG. 3.]
+
+  [Illustration: FIG. 4.]
+
+  Professor Osborne Reynolds in 1887 patented a water-brake (see _Proc.
+  Inst. C.E._ 99, p. 167), using Froude's turbine to obtain the highly
+  resisting spiral vortices, and arranging passages in the casing for
+  the entry of water at the hub of the wheel and its exit at the
+  circumference. Water enters at E (fig. 5), and finds its way into the
+  interior of the wheel, A, driving the air in front of it through the
+  air-passages K, K. Then following into the pocketed chambers V1, V2,
+  it is caught into the vortex, and finally escapes at the
+  circumference, flowing away at F. The air-ways k, k, in the fixed
+  vanes establish communication between the cores of the vortices and
+  the atmosphere. From {1/5} to 30 H.P. may be measured at 100 revs. per
+  min. by a brake-wheel of this kind 18 in. in diameter. For other
+  speeds the power varies as the cube of the speed. The casing is held
+  from turning by weights hanging on an attached arm. The cocks
+  regulating the water are connected to the casing, so that any tilting
+  automatically regulates the flow, and therefore the thickness of the
+  film in the vortex. In this way the brake may be arranged to maintain
+  a constant torque, not withstanding variation of the speed. In G.I.
+  Alden's brake (see _Trans. Amer. Soc. Eng._ vol. xi.) the resistance
+  is obtained by turning a cast iron disk against the frictional
+  resistance of two thin copper plates, which are held in a casing free
+  to turn upon the shaft, and are so arranged that the pressure between
+  the rubbing surfaces is controlled, and the heat developed by friction
+  carried away, by the regulated flow of water through the casing. The
+  torque required to hold the casing still against the action of the
+  disk measures the torque exerted by the shaft to which the disk is
+  keyed.
+
+  [Illustration: Fig. 5.]
+
+  _Transmission Dynamometers._--The essential part of many transmission
+  dynamometers is a spring whose deformation indirectly measures the
+  magnitude of the force transmitted through it. For many kinds of
+  spring the change of form is practically proportional to the force,
+  but the relation should always be determined experimentally. General
+  A.J. Morin (see _Notice sur divers appareils dynamometriques_, Paris,
+  1841), in his classical experiments on traction, arranged his
+  apparatus so that the change in form of the spring was continuously
+  recorded on a sheet of paper drawn under a style. For longer
+  experiments he used a "Compteur" or mechanical integrator, suggested
+  by J.V. Poncelet, from which the work done during a given displacement
+  could be read off directly. This device consists of a roller of radius
+  r, pressed into contact with a disk. The two are carried on a common
+  frame, so arranged that a change in form of the spring causes a
+  relative displacement of the disk and roller, the point of contact
+  moving radially from or towards the centre of the disk. The radial
+  distance x is at any instant proportional to the force acting through
+  the spring. The angular displacement, [theta], of the disk is made
+  proportional to the displacement, s, of the point of application of
+  the force by suitable driving gear. If d[phi] is the angular
+  displacement of the roller corresponding to displacements, d[theta] of
+  the disk, and ds of the point of application of P, a, and C constants,
+  then
+
+             xd[theta]   a
+    d[phi] = --------- = -- P ds = C.P ds,
+                 r       r
+                           _
+                          /s2
+  and therefore [phi] = C |  P ds;
+                         _/s1
+
+  that is, the angular displacement of the roller measures the work done
+  during the displacement from s1 to s2. The shaft carrying the roller
+  is connected to a counter so that [phi] may be observed. The angular
+  velocity of the shaft is proportional to the rate of working. Morin's
+  dynamometer is shown in fig. 6. The transmitting spring is made up of
+  two flat bars linked at their ends. Their centres s1, s2, are held
+  respectively by the pieces A, B, which together form a sliding pair.
+  The block A carries the disk D, B carries the roller R and counting
+  gear. The pulley E is driven from an axle of the carriage. In a
+  dynamometer used by F.W. Webb to measure the tractive resistance of
+  trains on the London & North-Western railway, a tractive pull or push
+  compresses two spiral springs by a definite amount, which is recorded
+  to scale by a pencil on a sheet of paper, drawn continuously from a
+  storage drum at the rate of 3 in. per mile, by a roller driven from
+  one of the carriage axles. Thus the diagram shows the tractive force
+  at any instant. A second pencil electrically connected to a clock
+  traces a time line on the diagram with a kick at every thirty seconds.
+  A third pencil traces an observation line in which a kick can be made
+  at will by pressing any one of the electrical pushes placed about the
+  car, and a fourth draws a datum line. The spring of the dynamometer
+  car used by W. Dean on the Great Western railway is made up of thirty
+  flat plates, 7 ft. 6 in. long, 5 in. x 5/8 in. at the centre, spaced
+  by distance pieces nibbed into the plates at the centre and by rollers
+  at the ends. The draw-bar is connected to the buckle, which is carried
+  on rollers, the ends of the spring resting on plates fixed to the
+  under-frame. The gear operating the paper roll is driven from the axle
+  of an independent wheel which is let down into contact with the rail
+  when required. This wheel serves also to measure the distance
+  travelled. A Morin disk and roller integrator is connected with the
+  apparatus, so that the work done during a journey may be read off.
+  Five lines are traced on the diagram.
+
+  [Illustration: FIG. 6.]
+
+  In spring dynamometers designed to measure a transmitted torque, the
+  mechanical problem of ascertaining the change of form of the spring is
+  complicated by the fact that the spring and the whole apparatus are
+  rotating together. In the Ayrton and Perry transmission dynamometer or
+  spring coupling of this type, the relative angular displacement is
+  proportional to the radius of the circle described by the end of a
+  light lever operated by mechanism between the spring-connected parts.
+  By a device used by W.E. Dalby (_Proc. Inst. C.E._ 1897-1898, p. 132)
+  the change in form of the spring is shown on a fixed indicator, which
+  may be placed in any convenient position. Two equal sprocket wheels
+  Q1, Q2, are fastened, the one to the spring pulley, the other to the
+  shaft. An endless band is placed over them to form two loops, which
+  during rotation remain at the same distance apart, unless relative
+  angular displacement occurs between Q1 and Q2 (fig. 7) due to a change
+  in form of the spring. The change in the distance d is proportional to
+  the change in the torque transmitted from the shaft to the pulley. To
+  measure this, guide pulleys are placed in the loops guided by a
+  geometric slide, the one pulley carrying a scale, and the other an
+  index. A recording drum or integrating apparatus may be arranged on
+  the pulley frames. A quick variation, or a periodic variation of the
+  magnitude of the force or torque transmitted through the springs,
+  tends to set up oscillations, and this tendency increases the nearer
+  the periodic time of the force variation approaches a periodic time of
+  the spring. Such vibrations may be damped out to a considerable extent
+  by the use of a dash-pot, or may be practically prevented by using a
+  relatively stiff spring.
+
+  [Illustration: FIG. 7.]
+
+  Every part of a machine transmitting force suffers elastic
+  deformation, and the force may be measured indirectly by measuring the
+  deformation. The relation between the two should in all cases be found
+  experimentally. G.A. Hirn (see _Les Pandynamometres_, Paris, 1876)
+  employed this principle to measure the torque transmitted by a shaft.
+  Signor Rosio used a telephonic method to effect the same end, and
+  mechanical, optical and telephonic devices have been utilized by the
+  Rev. F.J. Jervis-Smith. (See _Phil. Mag._ February 1898.)
+
+  H. Frahm,[1] during an important investigation on the torsional
+  vibration of propeller shafts, measured the relative angular
+  displacement of two flanges on a propeller shaft, selected as far
+  apart as possible, by means of an electrical device (_Engineering_,
+  6th of February 1903). These measurements were utilized in combination
+  with appropriate elastic coefficients of the material to find the
+  horse-power transmitted from the engines along the shaft to the
+  propeller. In this way the effective horse-power and also the
+  mechanical efficiency of a number of large marine engines, each of
+  several thousand horse-power, have been determined.
+
+  [Illustration: FIG. 8.]
+
+  When a belt, in which the maximum and minimum tensions are
+  respectively P and p lb., drives a pulley, the torque exerted is (P -
+  p)r lb. ft., r being the radius of the pulley plus half the thickness
+  of the belt. P and p may be measured directly by leading the belt
+  round two freely hanging guide pulleys, one in the tight, the other in
+  the slack part of the belt, and adjusting loads on them until a stable
+  condition of running is obtained. In W. Froude's belt dynamometer (see
+  _Proc. Inst. M.E._, 1858) (fig. 8) the guide pulleys G1, G2 are
+  carried upon an arm free to turn about the axis O. H is a pulley to
+  guide the approaching and receding parts of the belt to and from the
+  beam in parallel directions. Neglecting friction, the unbalanced
+  torque acting on the beam is 4r{P - p} lb. ft. If a force Q acting at
+  R maintains equilibrium, QR/4 = (P - p)r = T. Q is supplied by a
+  spring, the extensions of which are recorded on a drum driven
+  proportionally to the angular displacement of the driving pulley; thus
+  a work diagram is obtained. In the Farcot form the guide pulleys are
+  attached to separate weighing levers placed horizontally below the
+  apparatus. In a belt dynamometer built for the Franklin Institute from
+  the designs of Tatham, the weighing levers are separate and arranged
+  horizontally at the top of the apparatus. The weighing beam in the
+  Hefner-Alteneck dynamometer is placed transversely to the belt (see
+  _Electrotechnischen Zeitschrift_, 1881, 7). The force Q, usually
+  measured by a spring, required to maintain the beam in its central
+  position is proportional to (P - p). If the angle [theta]1 = [theta]2
+  = 120 deg., Q = (P - p) neglecting friction.
+
+  When a shaft is driven by means of gearing the driving torque is
+  measured by the product of the resultant pressure P acting between the
+  wheel teeth and the radius of the pitch circle of the wheel fixed to
+  the shaft. Fig. 9, which has been reproduced from J. White's _A New
+  Century of Inventions_ (Manchester, 1822), illustrates possibly the
+  earliest application of this principle to dynamometry. The wheel D,
+  keyed to the shaft overcoming the resistance to be measured, is driven
+  from wheel N by two bevel wheels L, L, carried in a loose pulley K.
+  The two shafts, though in a line, are independent. A torque applied to
+  the shaft A can be transmitted to D, neglecting friction, without
+  change only if the central pulley K is held from turning; the torque
+  required to do this is twice the torque transmitted.
+
+  [Illustration: FIG. 9.]
+
+  The torque acting on the armature of an electric motor is necessarily
+  accompanied by an equal and opposite torque acting on the frame. If,
+  therefore, the motor is mounted on a cradle free to turn about
+  knife-edges, the reacting torque is the only torque tending to turn
+  the cradle when it is in a vertical position, and may therefore be
+  measured by adjusting weights to hold the cradle in a vertical
+  position. The rate at which the motor is transmitting work is then
+  T2[pi]n/550 H.P., where n is the revolutions per second of the
+  armature.
+
+  See James Dredge, _Electric Illumination_, vol. ii. (London, 1885);
+  W.W. Beaumont, "Dynamometers and Friction Brakes," _Proc. Inst. C.E._
+  vol. xcv. (London, 1889); E. Brauer, "Ueber Bremsdynamometer and
+  verwandte Kraftmesser," _Zeitschrift des Vereins deutscher Ingenieure_
+  (Berlin, 1888); J.J. Flather, _Dynamometers and the Measurement of
+  Power_ (New York, 1893).     (W. E. D.)
+
+
+FOOTNOTE:
+
+  [1] H. Frahm, "Neue Untersuchungen ueber die dynamischen Vorgaenge in
+    den Wellenleitungen von Schiffsmaschinen mit besonderer
+    Beruecksichtigung der Resonanzschwingungen," _Zeitschrift des Vereins
+    deutscher Ingenieure_, 31st May 1902.
+
+
+
+
+DYNASTY (Gr. [Greek: dynasteia], sovereignty, the position of a [Greek:
+dynastes], lord, ruler, from [Greek: dynasthai], to be able, [Greek:
+dynamis], power), a family or line of rulers, a succession of sovereigns
+of a country belonging to a single family or tracing their descent to a
+common ancestor. The term is particularly used in the history of ancient
+Egypt as a convenient means of arranging the chronology.
+
+
+
+
+DYSART, a royal and police burgh and seaport of Fifeshire, Scotland, on
+the shore of the Firth of Forth, 2 m. N.E. of Kirkcaldy by the North
+British railway. Pop. (1901) 3562. It has a quaint old-fashioned
+appearance, many ancient houses in High Street bearing inscriptions and
+dates. The public buildings include a town hall, library, cottage
+hospital, mechanics' institute and memorial hall. Scarcely anything is
+left of the old chapel dedicated to St Dennis, which for a time was used
+as a smithy; and of the chapel of St Serf, the patron saint of the
+burgh, only the tower remains. The chief industries are the manufacture
+of bed and table linen, towelling and woollen cloth, shipbuilding and
+flax-spinning. There is a steady export of coal, and the harbour is
+provided with a wet dock and patent slip. In smuggling days the "canty
+carles" of Dysart were professed "free traders." In the 15th and 16th
+centuries the town was a leading seat of the salt industry ("salt to
+Dysart" was the equivalent of "coals to Newcastle"), but the salt-pans
+have been abandoned for a considerable period. Nail-making, once famous,
+is another extinct industry. During the time of the alliance between
+Scotland and Holland, which was closer in Fifeshire than in other
+counties, Dysart became known as Little Holland. To the west of the town
+is Dysart House, the residence of the earl of Rosslyn. With Burntisland
+and Kinghorn Dysart forms one of the Kirkcaldy district group of
+parliamentary burghs. The town is mentioned as early as 874 in connexion
+with a Danish invasion. Its name is said to be a corruption of the Latin
+_desertum_, "a desert," which was applied to a cave on the seashore
+occupied by St Serf. In the cave the saint held his famous colloquy with
+the devil, in which Satan was worsted and contemptuously dismissed. From
+James V. the town received the rights of a royal burgh. In 1559 it was
+the headquarters of the Lords of the Congregation, and in 1607 the scene
+of the meetings of the synod of Fife known as the Three Synods of
+Dysart. Ravensheugh Castle, on the shore to the west of the town, is the
+Ravenscraig of Sir Walter Scott's ballad of "Rosabelle."
+
+William Murray, a native of the place, was made earl of Dysart in 1643,
+and his eldest child and heir, a daughter, Elizabeth, obtained in 1670 a
+regrant of the title, which passed to the descendants of her first
+marriage with Sir Lionel Tollemache, Bart., of Helmingham; she married
+secondly the 1st duke of Lauderdale, but had no children by him, and
+died in 1698. This countess of Dysart (afterwards duchess of Lauderdale)
+was a famous beauty of the period, and notorious both for her amours and
+for her political influence. She was said to have been the mistress of
+Oliver Cromwell, and also of Lauderdale before her first husband's
+death, and was a leader at the court of Charles II. Wycherley is
+supposed to have aimed at her in his Widow Blackacre in the _Plain
+Dealer_. Her son, Lionel Tollemache (d. 1727), transmitted the earldom
+to his grandson Lionel (d. 1770), whose sons Lionel (d. 1799) and
+Wilbraham (d. 1821) succeeded; they died without issue, and their sister
+Louisa (d. 1840), who married John Manners, an illegitimate son of the
+second son of the 2nd duke of Rutland, became countess in her own right,
+being succeeded by her grandson (d. 1878), and his grandson, the 8th
+earl.
+
+The earldom of Dysart must not be confounded with that of Desart
+(Irish), created (barony 1733) in 1793, and held in the Cuffe family,
+who were originally of Creech St Michael, Somerset, the Irish branch
+dating from Queen Elizabeth's time.
+
+
+
+
+DYSENTERY (from the Gr. prefix [Greek: dys]-, in the sense of "bad," and
+[Greek: enteron], the intestine), also called "bloody flux," an
+infectious disease with a local lesion in the form of inflammation and
+ulceration of the lower portion of the bowels. Although at one time a
+common disease in Great Britain, dysentery is now very rarely met with
+there, and is for the most part confined to warm countries, where it is
+the cause of a large amount of mortality. (For the pathology see
+DIGESTIVE ORGANS.)
+
+Recently considerable advance has been made in our knowledge of
+dysentery, and it appears that there are two distinct types of the
+disease: (1) amoebic dysentery, which is due to the presence of the
+amoeba histolytica (of Schaudinn) in the intestine; (2) bacillary
+dysentery, which has as causative agent two separate bacteria, (a) that
+discovered by Shiga in Japan, (b) that discovered by Flexner in the
+Philippine Islands. With regard to the bacillary type, at first both
+organisms were considered to be identical, and the name _bacillus
+dysenteriae_ was given to them; but later it was shown that these
+bacilli are different, both in regard to their cultural characteristics
+and also in that one (Shiga) gives out a soluble toxin, whilst the
+other has so far resisted all efforts to discover it. Further, the
+serum of a patient affected with one of the types has a marked
+agglutinative power on the variety with which he is infected and not on
+the other.
+
+Clinically, dysentery manifests itself with varying degrees of
+intensity, and it is often impossible without microscopical examination
+to determine between the amoebic and bacillary forms. In well-marked
+cases the following are the chief symptoms. The attack is commonly
+preceded by certain premonitory indications in the form of general
+illness, loss of appetite, and some amount of diarrhoea, which gradually
+increases in severity, and is accompanied with griping pains in the
+abdomen (tormina). The discharges from the bowels succeed each other
+with great frequency, and the painful feeling of pressure downwards
+(tenesmus) becomes so intense that the patient is constantly desiring to
+defecate. The matters passed from the bowels, which at first resemble
+those of ordinary diarrhoea, soon change their character, becoming
+scanty, mucous or slimy, and subsequently mixed with, or consisting
+wholly of, blood, along with shreds of exudation thrown off from the
+mucous membrane of the intestine. The evacuations possess a peculiarly
+offensive odour characteristic of the disease. Although the
+constitutional disturbance is at first comparatively slight, it
+increases with the advance of the disease, and febrile symptoms come on
+attended with urgent thirst and scanty and painful flow of urine. Along
+with this the nervous depression is very marked, and the state of
+prostration to which the patient is reduced can scarcely be exceeded.
+Should no improvement occur death may take place in from one to three
+weeks, either from repeated losses of blood, or from gradual exhaustion
+consequent on the continuance of the symptoms, in which case the
+discharges from the bowels become more offensive and are passed
+involuntarily.
+
+When, on the other hand, the disease is checked, the signs of
+improvement are shown in the cessation of the pain, in the evacuations
+being less frequent and more natural, and in relief from the state of
+extreme depression. Convalescence is, however, generally slow, and
+recovery may be imperfect--the disease continuing in a chronic form,
+which may exist for a variable length of time, giving rise to much
+suffering, and not unfrequently leading to an ultimately fatal result.
+
+The dysentery poison appears to exert its effects upon the glandular
+structures of the large intestine, particularly in its lower part. In
+the milder forms of the disease there is simply a congested or inflamed
+condition of the mucous membrane, with perhaps some inflammatory
+exudation on its surface, which is passed off by the discharges from the
+bowels. But in the more severe forms ulceration of the mucous membrane
+takes place. Commencing in and around the solitary glands of the large
+intestine in the form of exudations, these ulcers, small at first,
+enlarge and run into each other, till a large portion of the bowel may
+be implicated in the ulcerative process. Should the disease be arrested
+these ulcers may heal entirely, but occasionally they remain, causing
+more or less disorganization of the coats of the intestines, as is often
+found in chronic dysentery. Sometimes, though rarely, the ulcers
+perforate the intestines, causing rapidly fatal inflammation of the
+peritoneum, or they may erode a blood vessel and produce violent
+haemorrhage. Even where they undergo healing they may cause such a
+stricture of the calibre of the intestinal canal as to give rise to the
+symptoms of obstruction which ultimately prove fatal. One of the
+severest complications of the disease is abscess of the liver, usually
+said to be solitary, and known as tropical abscess of the liver, but
+probably is more frequently multiple than is usually thought.
+
+_Treatment._--Where the disease is endemic or is prevailing
+epidemically, it is of great importance to use all preventive measures,
+and for this purpose the avoidance of all causes likely to precipitate
+an attack is to be enjoined. Exposure to cold after heat, the use of
+unripe fruit, and intemperance in eating and drinking should be
+forbidden; and the utmost care taken as to the quality of the food and
+drinking water. In houses or hospitals where cases of the disease are
+under treatment, disinfectants should be freely employed, and the
+evacuations of the patients removed as speedily as possible, having
+previously been sterilized in much the same manner as is employed in
+typhoid fever. In the milder varieties of this complaint, such as those
+occurring sporadically, and where the symptoms are probably due to
+matters in the bowels setting up the dysenteric irritation, the
+employment of diaphoretic medicines is to be recommended, and the
+administration of such a laxative as castor oil, to which a small
+quantity of laudanum has been added, will often, by removing the source
+of the mischief, arrest the attack; but a method of treatment more to be
+recommended is the use of salines in large doses, such as one drachm of
+sodium sulphate from four to eight times a day. This treatment may with
+advantage be combined with the internal administration of ipecacuanha,
+which still retains its reputation in this disease. Latterly, free
+irrigation of the bowel with astringents, such as silver nitrate,
+tannalbin, &c., has been attended with success in those cases which have
+been able to tolerate the injections. In many instances they cannot be
+used owing to the extreme degree of irritability of the bowel. The
+operation of appendicostomy, or bringing the appendix to the surface and
+using it as the site for the introduction of the irrigating fluid, has
+been attended with considerable success.
+
+In those cases due to Shiga's bacillus the ideal treatment has been put
+at our disposal by the preparation of a specific antitoxin; this has
+been given a trial in several grave epidemics of late, and may be said
+to be the most satisfactory treatment and offer the greatest hope of
+recovery. It is also of great use as a prophylactic.
+
+The preparations of morphia are of great value in the symptomatic
+treatment of the disease. They may be applied externally as
+fomentations, for the relief of tormina; by rectal injection for the
+relief of the tenesmus and irritability of the bowel; hypodermically in
+advanced cases, for the relief of the general distress. In amoebic
+dysentery, warm injections of quinine _per rectum_ have proved very
+efficacious, are usually well tolerated, and are not attended with any
+ill effects. The diet should be restricted, consisting chiefly of soups
+and farinaceous foods; more especially is this of importance in the
+chronic form. For the thirst ice may be given by the mouth. Even in the
+chronic forms, confinement to bed and restriction of diet are the most
+important elements of the treatment. Removal from the hot climate and
+unhygienic surroundings must naturally be attended to.
+
+  BIBLIOGRAPHY.--Allbutt and Rolleston, _System of Medicine_, vol. ii.
+  part ii. (1907), "Dysentery," Drs Andrew Davidson and Simon Flexner;
+  Davidson, _Hygiene and Diseases of Warm Climates_ (Edinburgh, 1903);
+  Fearnside in _Ind. Med. Gaz._ (July 1905); Ford in _Journal of
+  Tropical Medicine_ (July 15, 1904); Korentchewsky in _Bulletin de
+  l'Institut Pasteur_ (February 1905); Shiga: Osier and M'Crae's _System
+  of Medicine_, vol. ii. p. 781 (1907); Skschivan and Stefansky in
+  _Berliner klinische Wochenschrift_ (February 11, 1907); Vaillard and
+  Dopter, on the treatment by antidysenteric serum, _Annales de
+  l'Institut Pasteur_, No. 5, p. 326 (1906); J.A. Pottinger,
+  "Appendicostomy in Chronic Dysentery," _Lancet_ (December 28, 1907);
+  Robert Doerr, _Das Dysenterietoxin_ (Gustav Fischer, Jena, 1907); F.M.
+  Sandwith, "Hunterian Lecture on the Treatment of Dysentery," _Lancet_
+  (December 7, 1907).
+
+
+
+
+DYSPEPSIA (from the Gr. prefix [Greek: dys-], hard, ill, and [Greek:
+peptein], to digest), or indigestion, a term vaguely given to a group of
+pathological symptoms. There are comparatively few diseases of any
+moment where some of the phenomena of dyspepsia are not present as
+associated symptoms, and not infrequently these exist to such a degree
+as to mask the real disease, of which they are only complications. This
+is especially the case in many organic diseases of the alimentary canal,
+in which the symptoms of dyspepsia are often the most prominent. In its
+restricted meaning, however (and it is to this that the present article
+applies), the term is used to describe a functional derangement of the
+natural process of digestion, apart from any structural change in the
+organs concerned in the act.
+
+The causes of this trouble may be divided into (a) those which concern
+the food, and (b) those which concern the organism. Among the causes
+connected with the food are not only the indulgence in indigestible
+articles of diet, but the too common practice of eating too much of
+what may be otherwise quite wholesome and digestible; and irregular, too
+frequent or too infrequent meals. The quantity of food required by
+different individuals varies between wide limits, but also the quantity
+required by the same individual varies considerably according to
+circumstances, more food being needed in cold than in warm weather, and
+more in an active open-air occupation than in a sedentary one. The
+thorough mastication of the food is a very important precursor of
+digestion,[1] and this only too often fails, either owing to haste over
+meals or because of painful or deficient teeth. Again, the quality of
+the food is of importance, some kinds of flesh being harder and more
+difficult of mastication than others. This is especially the case with
+meat that has been smoked or salted, and with that cooked too soon after
+the death of the animal. Drinks are a common source of dyspepsia. Beer
+when new and its fermentation not completed is especially bad. Vinegar
+and acid wines, if taken in large quantities, tend to produce gastric
+catarrh, and tea is a very fruitful source of this trouble. Even too
+much water at meal-times may cause indigestion, since the food in the
+mouth is apt to be softened by the water instead of saliva, and also the
+gastric juice becomes unduly diluted, rendering the digestion in the
+stomach too slow and prolonged. Carious teeth and oral sepsis, from
+whatsoever cause, lead to the same trouble.
+
+Of the causes which concern the organism, nervous influences come first.
+Bad news may take away all power of digestion and even provoke vomiting,
+and any worry or mental trouble tends to bring on this condition.
+General weakness and atony of the body affects the stomach in like
+degree, and, if the muscles of the abdominal wall be much wasted, they
+become too weak to support the abdominal viscera in place. Hence results
+a general tendency for these organs to fall, giving rise to a condition
+of visceroptosis, of which an obstinate dyspepsia is a very marked
+feature. Adhesions of the intestines from old inflammatory troubles,
+floating kidney and bad circulation may each be a cause of painful
+digestion. Again, a dyspepsia that will not yield to treatment is often
+one of the symptoms of renal disease, or, in young people of fifteen to
+twenty years of age, it may be the earliest sign of a gouty diathesis,
+or even of a more serious condition still--incipient phthisis. Chronic
+dyspepsia, by weakening the organism, renders it more liable to fall a
+prey to the attacks of the tubercle bacillus, but, on the other hand,
+the tuberculous lesion in the lung is often accompanied by a most
+intractable form of dyspepsia. From this it is clear that any condition
+which lessens the general well-being of the organism as a whole, apart
+from its producing any permanent morbid condition in the stomach, may
+yet interfere with the normal digestive processes and so give rise to
+dyspepsia.
+
+The symptoms of dyspepsia, even when due to a like cause, are so
+numerous and diversified in different individuals that probably no
+description could exactly represent them as they occur in any given
+case. All that can be here attempted is to mention some of the more
+prominent morbid phenomena usually present in greater or less degree.
+
+Very briefly, a furred tongue, foul breath, disturbance of appetite,
+nausea and vomiting, oppression in the chest, pain, flatulence and
+distension, acidity, pyrosis and constipation or diarrhoea are a few of
+the commonest symptoms.
+
+When the attack is dependent on some error in diet, and the dyspepsia
+consequently more of an acute character, there is often pain followed
+with sickness and vomiting of the offensive matters, after which the
+patient soon regains his former healthy state. What are commonly known
+as "bilious attacks" are frequently of this character. In the more
+chronic cases of dyspepsia the symptoms are somewhat different. A
+sensation of discomfort comes on shortly after a meal, and is more of
+the nature of weight and distension in the stomach than of actual pain,
+although this too may be present. These feelings may come on after each
+meal, or only after certain meals, and they may arise irrespective of
+the kind of food taken, or only after certain articles of diet. As in
+most of such cases the food is long retained in the stomach, it is apt
+to undergo fermentive changes, one of the results of which is the
+accumulation of gases which cause flatulence and eructations of an acid
+or foul character. Occasionally quantities of hot, sour, tasteless or
+bitter fluid--pyrosis--or mouthfuls of half-digested food, regurgitate
+from the stomach. Temporary relief may be obtained when another meal is
+taken, but soon the uncomfortable sensations return as before. The
+appetite may be craving or deficient, or desirous of abnormal kinds of
+food. The tongue registers the gastric condition with great delicacy;--a
+pasty white fur on the tongue is considered a sign of weakness or atony
+of the digestive tract; a clean pointed tongue with large papillae, and
+rather red at the edges and tip, is a sign of gastric irritation; and a
+pale flabby tongue suggests the need of stimulating treatment.
+Constipation is more common in the chronic forms of dyspepsia, diarrhoea
+in the acute.
+
+Numerous disagreeable and painful sensations in other parts are
+experienced, and are indeed often more distressing than the merely
+gastric symptoms. Pains in the chest, shortness of breathing,
+palpitation, headache, giddiness, affections of vision, coldness of the
+extremities, and general languor are common accompaniments of dyspepsia;
+while the nervous phenomena are specially troublesome in the form of
+sleeplessness, irritability, despondency and hypochondriasis.
+
+As regards _treatment_ only a few general observations can be made. The
+careful arrangement of the diet is a matter of first importance.
+Quantity must be regulated by the digestive capabilities of the
+individual, his age, and the demands made upon his strength by work.
+There is little doubt that the danger is in most instances on the side
+of excess, and the rule which enjoins the cessation from eating before
+the appetite is satisfied is a safe one for dyspeptics. Due time, too,
+must be given for the digestion of a meal, and from four to six hours
+are in general required for this purpose. Long fasts, however, are
+nearly as hurtful as too frequent meals. Of no less importance is the
+kind of food taken, and on this point those who suffer from indigestion
+must ever exercise the greatest care. It must be borne in mind that
+idiosyncrasy often plays an important part in digestion, some persons
+being unable to partake without injury of substances which are generally
+regarded as wholesome and digestible. In most cases it is found very
+helpful to separate the protein from the farinaceous food, and the more
+severe the dyspepsia the more thoroughly should this be done, only
+relaxing as the dyspepsia yields. No fluid should be drunk at
+meal-times, but from one to two tumblers of hot water should be drunk
+from an hour to an hour and a half before food. This washes any remnant
+of the last meal from the stomach, and also supplies material for the
+free secretion of saliva and gastric juice, thus promoting and
+accelerating digestion. The only exception to this is in the case of a
+dilated stomach, when it is wholly contra-indicated. With regard to
+mastication, Sir Andrew Clark's rule is a very good one, and is more
+easily followed than the ideal theory laid down by Horace Fletcher,
+according to whom any food is digestible if properly treated while still
+in the mouth. Clark's rule is that as the mouth normally contains
+thirty-two teeth, thirty-two bites should be given before the food is
+swallowed. This, of course, is a practical doctor's concession to human
+weakness. Mr Fletcher would train every one to "chew" till the contents
+of the mouth were swallowed by reflex action without deliberate act; and
+he applies this theory of mastication and salivation also to drinks
+(except water). Again, a lack of warmth being a source of dyspepsia,
+this should be attended to, the back of the neck, the front of the
+abdomen and the feet being the parts that require special attention. The
+feet should be raised on a stool, the ankles protected with warm
+stockings and a woollen "cummerbund" wound two or three times round the
+body. Experience has shown that in this complaint no particular kind of
+food or avoidance of food is absolutely to be relied on, but that in
+general the best diet is one of a mixed animal and vegetable kind,
+simply but well cooked. The partaking of many dishes, of highly-seasoned
+or salted meats, raw vegetables, newly-baked bread, pastry and
+confectionery are all well-known common causes of dyspepsia, and should
+be avoided. When even the simple diet usually taken is found to
+disagree, it may be necessary to change it temporarily for a still
+lighter form, such as a milk diet, and that even in very moderate
+quantity.
+
+The employment of alcoholic stimulants to assist digestion is largely
+resorted to, both with and without medical advice. While it seems
+probable that in certain cases of atonic dyspepsia, particularly in the
+feeble and aged, the moderate administration of alcohol has the effect
+of stimulating the secretion of gastric juice, and is an important
+adjuvant to other remedies, the advantages of its habitual use as an aid
+to digestion by the young and otherwise healthy, is more than
+questionable, and it will generally be found that among them, those are
+least troubled with indigestion who abstain from it. Rest should be
+taken both before and after food, and general hygienic measures are
+highly important, since whatever improves the state of the health will
+have a favourable influence on digestion. Hence regular exercise in the
+open air, early rising and the cold bath are to be strongly recommended.
+
+The medicinal treatment of dyspepsia can only be undertaken by a
+physician, but the following is a very brief resume of the drugs he
+depends on to-day. Bicarbonate of soda with some bitter, as quassia,
+gentian or columba, is much in vogue as a direct gastric stimulant. In
+irritable dyspepsia some form of bismuth in solution or powder; and, to
+assist digestion through the nervous system, nux vomica and strychnine
+can be relied on. To give directly digestive material, hydrochloric
+acid, pepsin and rennet are prescribed in many forms, but where there is
+much vomiting ingluvin is more efficacious than pepsin. When farinaceous
+food is badly borne, diastase is helpful, given either before or with
+the meal. To prevent fermentation, phenol, creasote and sulpho-carbolate
+of soda are all extremely useful in skilled hands; and for intestinal
+decomposition and flatulent distension, bismuth salicylate with salol or
+ss-naphthol is much used. Cyllin, and charcoal in many forms, may be
+taken both for gastric and intestinal flatulence. But all these drugs,
+of proved value though they are, must be modified and combined to suit
+the special idiosyncrasy of the patient, and are therefore often worse
+than useless in inexperienced hands. The condition of the bowels must
+always have due attention.
+
+  See also DIGESTIVE ORGANS; NUTRITION and DIETETICS.
+
+
+FOOTNOTE:
+
+  [1] This aspect of the matter--"buccal digestion"--has been specially
+    emphasized in recent years by Horace Fletcher of the United States,
+    whose experience of the results of systematic "chewing," confirmed by
+    Sir M. Foster, Prof. Chittenden and others, has almost revolutionized
+    the science of dietetics.
+
+
+
+
+DYSTELEOLOGY, a modern word invented by Haeckel (_Evolution of Man_) for
+the doctrine of purposelessness, as opposed to the philosophical
+doctrine of design (Teleology).
+
+
+
+
+DZUNGARIA, DSONGARIA, or JUNGARIA, a former Mongolian kingdom of Central
+Asia, raised to its highest pitch by Kaldan or Bushtu Khan in the latter
+half of the 17th century, but completely destroyed by Chinese invasion
+about 1757-1759. It has played an important part in the history of
+Mongolia and the great migrations of Mongolian stems westward. Now its
+territory belongs partly to the Chinese empire (east Turkestan and
+north-western Mongolia) and partly to Russian Turkestan (provinces of
+Semiryechensk and Semipalatinsk). It derived its name from the Dsongars,
+or Songars, who were so called because they formed the left wing
+(_dson_, left; _gar_, hand) of the Mongolian army. Its widest limit
+included Kashgar, Yarkand, Khotan, the whole region of the T'ien Shan,
+or Tian-shan, Mountains, and in short the greater proportion of that
+part of Central Asia which extends from 35 deg. to 50 deg. N. and from 72 deg. to
+97 deg. E. The name, however, is more properly applied only to the present
+Chinese province of T'ien Shan-pei-lu and the country watered by the
+Ili. As a political or geographical term it has practically disappeared
+from the map; but the range of mountains stretching north-east along the
+southern frontier of the Land of the Seven Streams, as the district to
+the south-east of the Balkhash Lake is called, preserves the name of
+Dzungarian Range.
+
+
+
+
+E The fifth symbol in the English alphabet occupies also the same
+position in Phoenician and in the other alphabets descended from
+Phoenician. As the Semitic alphabet did not represent vowels, E was
+originally an aspirate. Its earliest form, while writing is still from
+right to left, is [symbol], the upright being continued some distance
+below the lowest of the cross-strokes. In some of the Greek alphabets it
+appears as [symbol] with the upright prolonged at both top and bottom,
+but it soon took the form with which we are familiar, though in the
+earlier examples of this form the cross-strokes are not horizontal but
+drop at an angle, [symbol]. In Corinth and places under its early
+influence like Megara, or colonized from it like Corcyra, the symbol for
+_e_ takes the form [symbol] or [symbol], while at Sicyon in the 6th and
+5th centuries B.C. it is represented by [symbol]. In early Latin it was
+sometimes represented by two perpendicular strokes of equal length,
+[symbol].
+
+In the earliest Greek inscriptions and always in Latin the symbol E
+represented both the short and the long _e_-sound. In Greek also it was
+often used for the close long sound which arose either by contraction of
+two short _e_-sounds or by the loss of a consonant, after a short
+_e_-sound, as in [Greek: phileite], "you love," for [Greek: phileete],
+and [Greek: phaeinos], "bright," out of an earlier [Greek: phaesnos].
+The Ionian Greeks of Asia Minor, who had altogether lost the aspirate,
+were the first to use the symbol H for the long _e_-sound, and in
+official documents at Athens down to 403 B.C., when the Greek alphabet
+as still known was adopted by the state, E represented [epsilon], [eta]
+and the sound arising by contraction or consonant loss as mentioned
+above which henceforth was written with two symbols, [Greek: ei], and
+being really a single sound is known as the "spurious diphthong." There
+were some minor distinctions in usage of the symbols E and H which need
+not here be given in detail. The ancient Greek name was [Greek: ei], not
+_Epsilon_ as popularly supposed; the names of the Greek letters are
+given from Kallias, an earlier contemporary of Euripides, in Athenaeus
+x. p. 453 d.
+
+In Greek the short _e_-sound to which E was ultimately limited was a
+close sound inclining more towards _i_ than _a_; hence the
+representation of the contraction of [Greek: ee] by [Greek: ei]. Its
+value in Latin was exactly the opposite, the Latin short _e_ being open,
+and the long close. In English there has been a gradual narrowing of the
+long vowels, _a_ becoming approximately _ei_ and _e_ becoming _i_
+(Sweet, _History of English Sounds_, Sec.Sec. 781, 817 ff. 2nd ed.). In
+languages where the diphthong _ai_ has become a monophthong, the
+resulting sound is some variety of long _e_. Often the gradual
+assimilation can be traced through the intermediate stage of _ae_ to
+_e_, as in the Old Latin _aidilis_, which in classical Latin is
+_aedilis_, and in medieval MSS. _edilis_.
+
+The variety of spelling in English for the long and short _e_-sounds is
+conveniently illustrated in Miss Soames's _Introduction to the Study of
+Phonetics_, pp. 16 and 20.     (P. Gi.)
+
+
+
+
+EA (written by means of two signs signifying "house" and "water"), in
+the Babylonian religion, originally the patron deity of Eridu, situated
+in ancient times at the head of the Persian Gulf, but now, by reason of
+the constant accumulation of soil in the Euphrates valley, at some
+distance from the gulf. Eridu, meaning "the good city," was one of the
+oldest settlements in the Euphrates valley, and is now represented by
+the mounds known as Abu Shahrein. In the absence of excavations on that
+site, we are dependent for our knowledge of Ea on material found
+elsewhere. This is, however, sufficient to enable us to state definitely
+that Ea was a water-deity, and there is every reason to believe that the
+Persian Gulf was the body of water more particularly sacred to him.
+Whether Ea (or A-e as some scholars prefer) represents the real
+pronunciation of his name we do not know. All attempts to connect Ea
+with Yah and Yahweh are idle conjectures without any substantial basis.
+He is figured as a man covered with the body of a fish, and this
+representation, as likewise the name of his temple E-apsu, "house of
+the watery deep," points decidedly to his character as a god of the
+waters (see OANNES). Of his cult at Eridu, which reverts to the oldest
+period of Babylonian history, nothing definite is known beyond the fact
+that the name of his temple was E-saggila, "the lofty house"--pointing
+to a staged tower as in the case of the temple of Bel (q.v.) at Nippur,
+known as E-Kur, i.e. "mountain house"--and that incantations, involving
+ceremonial rites, in which water as a sacred element played a prominent
+part, formed a feature of his worship. Whether Eridu at one time also
+played an important political role is not certain, though not
+improbable. At all events, the prominence of the Ea cult led, as in the
+case of Nippur, to the survival of Eridu as a sacred city, long after it
+had ceased to have any significance as a political centre. Myths in
+which Ea figures prominently have been found in Assur-bani-pal's
+library, indicating that Ea was regarded as the protector and teacher of
+mankind. He is essentially a god of civilization, and it was natural
+that he was also looked upon as the creator of man, and of the world in
+general. Traces of this view appear in the Marduk epic celebrating the
+achievements of this god, and the close connexion between the Ea cult at
+Eridu and that of Marduk also follows from two considerations: (1) that
+the name of Marduk's sanctuary at Babylon bears the same name,
+E-saggila, as that of Ea in Eridu, and (2) that Marduk is generally
+termed the son of Ea, who derives his powers from the voluntary
+abdication of the father in favour of his son. Accordingly, the
+incantations originally composed for the Ea cult were re-edited by the
+priests of Babylon and adapted to the worship of Marduk, and, similarly,
+the hymns to Marduk betray traces of the transfer of attributes to
+Marduk which originally belonged to Ea.
+
+It is, however, more particularly as the third figure in the triad, the
+two other members of which were Anu (q.v.) and Bel (q.v.), that Ea
+acquires his permanent place in the pantheon. To him was assigned the
+control of the watery element, and in this capacity he becomes the _shar
+apsi_, i.e. king of the Apsu or "the deep." The Apsu was figured as an
+ocean encircling the earth, and since the gathering place of the dead,
+known as Aralu, was situated near the confines of the Apsu, he was also
+designated as En-Ki, i.e. "lord of that which is below," in contrast to
+Anu, who was the lord of the "above" or the heavens. The cult of Ea
+extended throughout Babylonia and Assyria. We find temples and shrines
+erected in his honour, e.g. at Nippur, Girsu, Ur, Babylon, Sippar and
+Nineveh, and the numerous epithets given to him, as well as the various
+forms under which the god appears, alike bear witness to the popularity
+which he enjoyed from the earliest to the latest period of
+Babylonian-Assyrian history. The consort of Ea, known as Damkina, "lady
+of that which is below," or Nin-Ki, having the same meaning, or
+Damgal-nunna, "great lady of the waters," represents a pale reflection
+of Ea and plays a part merely in association with her lord.     (M. Ja.)
+
+
+
+
+EABANI, the name of the friend of Gilgamesh, the hero in the Babylonian
+epic (see GILGAMESH, EPIC OF). Eabani, whose name signifies "Ea
+creates," pointing to the tradition which made the god Ea (q.v.) the
+creator of mankind, is represented in the epic as the type of the
+primeval man. He is a wild man who lives with the animals of the field
+until lured away from his surroundings by the charms of a woman. Created
+to become a rival to Gilgamesh, he strikes up a friendship with the
+hero, and together they proceed to a cedar forest guarded by Khumbaba,
+whom they kill. The goddess Irnina (a form of Ishtar, q.v.) in revenge
+kills Eabani, and the balance of the epic is taken up with Gilgamesh's
+lament for his friend, his wanderings in quest of a remote ancestor,
+Ut-Napishtim, from whom he hopes to learn how he may escape the fate of
+Eabani, and his finally learning from his friend of the sad fate in
+store for all mortals except the favourites of the god, like
+Ut-Napishtim, to whom immortal life is vouchsafed as a special boon.
+     (M. Ja.)
+
+
+
+
+EACHARD, JOHN (1636?-1697), English divine, was born in Suffolk, and was
+educated at Catharine Hall, Cambridge, of which he became master in 1675
+in succession to John Lightfoot. He was created D.D. in 1676 by royal
+mandate, and was twice (in 1679 and 1695) vice-chancellor of the
+university. He died on the 7th of July 1697. In 1670 he had published
+anonymously a humorous satire entitled _The Ground and Occasions of the
+Contempt of the Clergy enquired into in a letter to R. L._, which
+excited much attention and provoked several replies, one of them being
+from John Owen. These were met by _Some Observations, &c., in a second
+letter to R. L._ (1671), written in the same bantering tone as the
+original work. Eachard attributed the contempt into which the clergy had
+fallen to their imperfect education, their insufficient incomes, and the
+want of a true vocation. His descriptions, which were somewhat
+exaggerated, were largely used by Macaulay in his _History of England_.
+He gave amusing illustrations of the absurdity and poverty of the
+current pulpit oratory of his day, some of them being taken from the
+sermons of his own father. He attacked the philosophy of Hobbes in his
+_Mr Hobb's State of Nature considered; in a dialogue between Philautus
+and Timothy_ (1672), and in his _Some Opinions of Mr Hobbs considered in
+a second dialogue_ (1673). These were written in their author's chosen
+vein of light satire, and Dryden praised them as highly effective within
+their own range. Eachard's own sermons, however, were not superior to
+those he satirized. Swift (_Works_, xii. 279) alludes to him as a signal
+instance of a successful humorist who entirely failed as a serious
+writer.
+
+  A collected edition of his works in three volumes, with a notice of
+  his life, was published in 1774. The _Contempt of the Clergy_ was
+  reprinted in E. Arber's _English Garner_. _A Free Enquiry into the
+  Causes of the very great Esteem that the Nonconforming Preachers are
+  generally in with their Followers_ (1673) has been attributed to
+  Eachard on insufficient grounds.
+
+
+
+
+EADBALD (d. 640), king of Kent, succeeded to the throne on the death of
+his father AEthelberht in 616. He had not been influenced by the teaching
+of the Christian missionaries, and his first step on his accession was
+to marry his father's widow. After his subsequent conversion by
+Laurentius, archbishop of Canterbury, he recalled the bishops Mellitus
+and Justus, and built a church dedicated to the Virgin at Canterbury. He
+arranged a marriage between his sister AEthelberg and Edwin of
+Northumbria, on whose defeat and death in 633 he received his sister and
+Paulinus, and offered the latter the bishopric of Rochester. Eadbald
+married Emma, a Frankish princess, and died on the 20th of January 640.
+
+  See Bede, _Historia ecclesiastica_ (ed. C. Plummer, Oxford, 1896);
+  _Saxon Chronicle_ (ed. J. Earle and C. Plummer, Oxford, 1899).
+
+
+
+
+EADIE, JOHN (1810-1876), Scottish theologian and biblical critic, was
+born at Alva, in Stirlingshire, on the 9th of May 1810. Having taken the
+arts curriculum at Glasgow University, he studied for the ministry at
+the Divinity Hall of the Secession Church, a dissenting body which, on
+its union a few years later with the Relief Church, adopted the title
+United Presbyterian. In 1835 he became minister of the Cambridge Street
+Secession church in Glasgow, and for many years he was generally
+regarded as the leading representative of his denomination in Glasgow.
+As a preacher, though he was not eloquent, he was distinguished by good
+sense, earnestness and breadth of sympathy. In 1863 he removed with a
+portion of his congregation to a new church at Lansdowne Crescent. In
+1843 Eadie was appointed professor of biblical literature and
+hermeneutics in the Divinity Hall of the United Presbyterian body. He
+held this appointment along with his ministerial charge till the close
+of his life. Though not a profound scholar, he was surpassed by few
+biblical commentators of his day in range of learning, and in soundness
+of judgment. In the professor's chair, as in the pulpit, his strength
+lay in the tact with which he selected the soundest results of biblical
+criticism, whether his own or that of others, and presented them in a
+clear and connected form, with a constant view to their practical
+bearing. He received the degree of LL.D. from Glasgow in 1844, and that
+of D.D. from St Andrews in 1850.
+
+His publications were connected with biblical criticism and
+interpretation, some of them being for popular use and others more
+strictly scientific. To the former class belong the _Biblical
+Cyclopaedia_, his edition of _Cruden's Concordance_, his _Early Oriental
+History_, and his discourses on the _Divine Love_ and on _Paul the
+Preacher_; to the latter his commentaries on the Greek text of St Paul's
+epistles to the Ephesians, Colossians, Philippians and Galatians,
+published at intervals in four volumes. His last work was the _History
+of the English Bible_ (2 vols., 1876). He rendered good service as one
+of the revisers of the authorized version. He died at Glasgow on the 3rd
+of June 1876. His valuable library was bought and presented to the
+United Presbyterian College.
+
+
+
+
+EADMER, or EDMER (c. 1060-c. 1124), English historian and ecclesiastic,
+was probably, as his name suggests, of English, and not of Norman
+parentage. He became a monk in the Benedictine monastery of Christ
+Church, Canterbury, where he made the acquaintance of Anselm, at that
+time visiting England as abbot of Bec. The intimacy was renewed when
+Anselm became archbishop of Canterbury in 1093; thenceforward Eadmer was
+not only his disciple and follower, but his friend and director, being
+formally appointed to this position by Pope Urban II. In 1120 he was
+nominated to the archbishopric of St Andrews, but as the Scots would not
+recognize the authority of the see of Canterbury he was never
+consecrated, and soon afterwards he resigned his claim to the
+archbishopric. His death is generally assigned to the year 1124.
+
+Eadmer left a large number of writings, the most important of which is
+his _Historiae novorum_, a work which deals mainly with the history of
+England between 1066 and 1122. Although concerned principally with
+ecclesiastical affairs scholars agree in regarding the _Historiae_ as
+one of the ablest and most valuable writings of its kind. It was first
+edited by John Selden in 1623 and, with Eadmer's _Vita Anselmi_, has
+been edited by Martin Rule for the "Rolls Series" (London, 1884). The
+_Vita Anselmi_, first printed at Antwerp in 1551, is probably the best
+life of the saint. Less noteworthy are Eadmer's lives of St Dunstan, St
+Bregwin, archbishop of Canterbury, and St Oswald, archbishop of York;
+these are all printed in Henry Wharton's _Anglia Sacra_, part ii.
+(1691), where a list of Eadmer's writings will be found. The manuscripts
+of most of Eadmer's works are preserved in the library of Corpus Christi
+College, Cambridge.
+
+  See M. Rule, _On Eadmer's Elaboration of the first four Books of
+  "Historiae novorum"_ (1886); and Pere Ragey, _Eadmer_ (Paris, 1892).
+
+
+
+
+EADS, JAMES BUCHANAN (1820-1887), American engineer, was born at
+Lawrenceburg, Indiana, on the 23rd of May 1820. His first engineering
+work of any importance was in raising sunken steamers. In 1845 he
+established glass works in St Louis. During the Civil War he constructed
+ironclad steamers and mortar boats for the Federal government. His next
+important engineering achievement was the construction of the great
+steel arch bridge across the Mississippi at St Louis (see BRIDGE, fig.
+29), upon which he was engaged from 1867 till 1874. The work, however,
+upon which his reputation principally rests was his deepening and fixing
+the channel at the mouths of the Mississippi by means of jetties,
+whereby the narrowed stream was made to scour out its own channel and
+carry the sediment out to sea. Shortly before his death he projected a
+scheme for a ship railway across the Isthmus of Tehuantepec, in lieu of
+an isthmian canal. He died at Nassau, in the Bahamas, on the 8th of
+March 1887.
+
+
+
+
+EAGLE (Fr. _aigle_, from the Lat. _aquila_), the name generally given to
+the larger diurnal birds of prey which are not vultures; but the limits
+of the subfamily _Aquilinae_ have been very variously assigned by
+different writers on systematic ornithology, and there are eagles
+smaller than certain buzzards. By some authorities the _Laemmergeier_ of
+the Alps, and other high mountains of Europe, North Africa and Asia, is
+accounted an eagle, but by others the genus _Gypaetus_ is placed with
+the _Vulturidae_ as its common English name (bearded vulture)
+shows. There are also other forms, such as the South American _Harpyia_
+and its allies, which though generally called eagles have been ranked as
+buzzards. In the absence of any truly scientific definition of the
+family _Aquilinae_ it is best to leave these and many other more or less
+questionable members of the group--such as the genera _Spizaetus_,
+_Circaetus_, _Spilornis_, _Helotarsus_, and so forth--and to treat here
+of those whose position cannot be gainsaid.
+
+[Illustration: FIG. 1.--Sea-Eagle.]
+
+True eagles inhabit all the regions of the world, and some seven or
+eight species at least are found in Europe, of which two are resident in
+the British Islands. In England and in the Lowlands of Scotland eagles
+only exist as stragglers; but in the Hebrides and some parts of the
+Highlands a good many may yet be found, and their numbers appear to have
+rather increased of late years than diminished; for the foresters and
+shepherds, finding that a high price can be got for their eggs, take
+care to protect the owners of the eyries, which are nearly all well
+known, and to keep up the stock by allowing them at times to rear their
+young. There are also now not a few occupiers of Scottish forests who
+interfere so far as they can to protect the king of birds.[1] In Ireland
+the extirpation of eagles seems to have been carried on almost
+unaffected by the prudent considerations which in the northern kingdom
+have operated so favourably for the race, and except in the wildest
+parts of Donegal, Mayo and Kerry, eagles in the sister island are almost
+birds of the past.
+
+Of the two British species the erne (Icel. _Oern_) or sea-eagle (by some
+called also the white-tailed and cinereous eagle)--_Haliaetus
+albicilla_--affects chiefly the coast and neighbourhood of inland
+waters, living in great part on the fish and refuse that is thrown up on
+the shore, though it not unfrequently takes living prey, such as lambs,
+hares and rabbits. On these last, indeed, young examples mostly feed
+when they wander southward in autumn, as they yearly do, and appear in
+England. The adults (fig. 1) are distinguished by their prevalent
+greyish-brown colour, their pale head, yellow beak and white
+tail--characters, however, wanting in the immature, which do not assume
+the perfect plumage for some three or four years. The eyry is commonly
+placed in a high cliff or on an island in a lake--sometimes on the
+ground, at others in a tree--and consists of a vast mass of sticks in
+the midst of which is formed a hollow lined with _Luzula sylvatica_ (as
+first observed by John Wolley) or some similar grass, and here are laid
+the two or three white eggs. In former days the sea-eagle seems to have
+bred in several parts of England--as the Lake district, and possibly
+even in the Isle of Wight and on Dartmoor. This species inhabits all the
+northern part of the Old World from Iceland to Kamchatka, and breeds in
+Europe so far to the southward as Albania. In the New World, however, it
+is only found in Greenland, being elsewhere replaced by the white-headed
+or bald eagle, _H. leucocephalus_, a bird of similar habits, and the
+chosen emblem of the United States of America. In the far east of Asia
+occurs a still larger and finer sea-eagle, _H. pelagicus_, remarkable
+for its white thighs and upper wing-coverts. South-eastern Europe and
+India furnish a much smaller species, _H. leucoryphus_, which has its
+representative, _H. leucogaster_, in the Malay Archipelago and
+Australia, and, as allies in South Africa and Madagascar, _H. vocifer_
+and _H. vociferoides_ respectively. All these eagles may be
+distinguished by their scaly tarsi, while the group next to be treated
+of have the tarsi feathered to the toes.
+
+[Illustration: FIG. 2.--Mountain-Eagle.]
+
+The golden or mountain eagle, _Aquila chrysaetus_, is the second British
+species. This also formerly inhabited England, and a nest, found in 1668
+in the Peak of Derbyshire, is well described by Willughby, in whose time
+it was said to breed also in the Snowdon range. It seldom if ever
+frequents the coast, and is more active on the wing than the sea-eagle,
+being able to take some birds as they fly, but a large part of its
+sustenance is the flesh of animals that die a natural death. Its eyry is
+generally placed and built like that of the other British species,[2]
+but the neighbourhood of water is not requisite. The eggs, from two to
+four in number, vary from a pure white to a mottled, and often highly
+coloured, surface, on which appear different shades of red and purple.
+The adult bird (fig. 2) is of a rich dark brown, with the elongated
+feathers of the neck, especially on the nape, light tawny, in which
+imagination sees a "golden" hue, and the tail marbled with brown and
+ashy-grey. In the young the tail is white at the base, and the neck has
+scarcely any tawny tint. The golden eagle does not occur in Iceland, but
+occupies suitable situations over the rest of the Palaearctic Region and
+a considerable portion of the Nearctic--though the American bird has
+been, by some, considered a distinct species. Domesticated, it has many
+times been trained to take prey for its master in Europe, and to this
+species is thought to belong an eagle habitually used by the Kirghiz
+Tatars, who call it _Bergut_ or _Bearcoot_, for the capture of
+antelopes, foxes and wolves. It is carried hooded on horseback or on a
+perch between two men, and released when the quarry is in sight. Such a
+bird, when well trained, is valued, says P.S. Pallas, at the price of
+two camels. It is quite possible, however, that more than one kind of
+eagle is thus used, and the services of _A. heliaca_ (which is the
+imperial eagle of some writers[3]) and of _A. mogilnik_--both of which
+are found in central Asia, as well as in south-eastern Europe--may also
+be employed.
+
+A smaller form of eagle, which has usually gone under the name of _A.
+naevia_, is now thought by the best authorities to include three local
+races, or, in the eyes of some, species. They inhabit Europe, North
+Africa and western Asia to India, and two examples of one of them--_A.
+clanga_, the form which is somewhat plentiful in north-eastern
+Germany--have occurred in Cornwall. The smallest true eagle is _A.
+pennata_, which inhabits southern Europe, Africa and India. Differing
+from other eagles of their genus by its wedge-shaped tail, though
+otherwise greatly resembling them, is the _A. audax_ of Australia.
+Lastly may be noticed here a small group of eagles, characterized by
+their long legs, forming the genus _Nisaetus_, of which one species, _N.
+fasciatus_, is found in Europe.      (A. N.)
+
+
+FOOTNOTES:
+
+  [1] Lord Breadalbane (d. 1871) was perhaps the first large landowner
+    who set the example that has been since followed by others. On his
+    unrivalled forest of Black Mount, eagles--elsewhere persecuted to the
+    death--were by him ordered to be unmolested so long as they were not
+    numerous enough to cause considerable depredations on the farmers'
+    flocks. He thought that the spectacle of a soaring eagle was a
+    fitting adjunct to the grandeur of his Argyllshire mountain scenery,
+    and a good equivalent for the occasional loss of a lamb, or the
+    slight deduction from the rent paid by his tenantry in consequence.
+
+  [2] As already stated, the site chosen varies greatly. Occasionally
+    placed in a niche in what passes for a perpendicular cliff to which
+    access could only be gained by a skilful cragsman with a rope, the
+    writer has known a nest to within 10 or 15 yds. of which he rode on a
+    pony. Two beautiful views of as many golden eagles' nests, drawn on
+    the spot by Joseph Wolf, are given in the _Ootheca Wolleyana_, and a
+    fine series of eggs is also figured in the same work.
+
+  [3] Which species may have been the traditional emblem of Roman
+    power, and the _Ales Jovis_, is very uncertain.
+
+
+
+
+EAGLEHAWK, a borough of Bendigo county, Victoria, Australia, 105 m. by
+rail N.N.W. of Melbourne and 4 m. from Bendigo, with which it is
+connected by steam tramway. Pop. (1901) 8130. It stands on the Bendigo
+gold-bearing reef, and its mines are important.
+
+
+
+
+EAGRE (a word of obscure origin; the earliest form seems to be _higre_,
+Latinized as _higra_, which William of Malmesbury gives as the name of
+the bore in the Severn; the _New English Dictionary_ rejects the usual
+derivations from the O. Eng. _eagor_ or _egor_, which is seen in
+compounds meaning "flood," and also the connexion with the Norse sea-god
+_Aegir_), a tide wave of great height rushing up an estuary (see BORE),
+used locally of the Humber and Trent.
+
+
+
+
+EAKINS, THOMAS (1844-   ), American portrait and figure painter, was
+born at Philadelphia, on the 25th of July 1844. A pupil of J.L. Gerome,
+in the Ecole des Beaux-Arts, Paris, and Also of Leon Bonnat, besides
+working in the studio of the sculptor Dumont, he became a prolific
+portrait painter. He also painted genre pictures, sending to the
+Centennial Exhibition at Philadelphia, in 1876, the "Chess Players," now
+in the Metropolitan Museum of Art, New York. A large canvas, "The
+Surgical Clinic of Professor Gross," owned by Jefferson Medical College,
+Philadelphia, contains many life-sized figures. Eakins, with his pupil
+Samuel Murray (b. 1870), modelled the heroic "Prophets" for the
+Witherspoon Building, Philadelphia, and his work in painting has a
+decided sculptural quality. He was for some years professor of anatomy
+at the schools of the Pennsylvania Academy of Fine Arts in Philadelphia.
+A man of great inventiveness, he experimented in many directions,
+depicting on canvas modern athletic sports, the negro, and early
+American life, but he is best known by his portraits. He received awards
+at the Columbian (1893), Paris (1900), Pan-American (1900), and the St
+Louis (1904), Expositions; and won the Temple medal in the Pennsylvania
+Academy of Fine Arts, and the Proctor prize of the National Academy of
+Design.
+
+
+
+
+EALING, a municipal borough in the Ealing parliamentary division of
+Middlesex, England, suburban to London, 9 m. W. of St Paul's cathedral.
+Pop. (1891) 23,979; (1901) 33,031. The nucleus of the town, the ancient
+village, lies south of the highroad to Uxbridge, west of the open Ealing
+Common. The place is wholly residential. At St Mary's church, almost
+wholly rebuilt c. 1870, are buried John Oldmixon, the historian (d.
+1742), and Horne Tooke (d. 1812). The church of All Saints (1905)
+commemorates Spencer Perceval, prime minister, who was assassinated in
+the House of Commons in 1812. It was erected under the will of his
+daughter Frederica, a resident of Ealing. Gunnersbury Park, south of
+Ealing Common, is a handsome Italian mansion. Among former owners of the
+property was Princess Amelia, daughter of George II., who lived here
+from 1761 till her death in 1786. The name of Gunnersbury is said to be
+traceable to the residence here of Gunilda, niece of King Canute. The
+manor of Ealing early belonged to the see of London, but it is not
+mentioned in Domesday and its history is obscure.
+
+
+
+
+EAR (common Teut.; O.E. _eare_, Ger. _Ohr_, Du. _oor_, akin to Lat.
+_auris_, Gr. [Greek: ous]), in anatomy, the organ of hearing. The human
+ear is divided into three parts--external, middle and internal. The
+external ear consists of the pinna and the external auditory meatus. The
+pinna is composed of a yellow fibro-cartilaginous framework covered by
+skin, and has an external and an internal or cranial surface. Round the
+margin of the external surface in its upper three quarters is a rim
+called the helix (fig. 1, a), in which is often seen a little prominence
+known as Darwin's tubercle, representing the folded-over apex of a
+prick-eared ancestor. Concentric with the helix and nearer the meatus is
+the antihelix (c), which, above, divides into two limbs to enclose the
+triangular fossa of the antihelix. Between the helix and the antihelix
+is the fossa of the helix. In front of the antihelix is the deep fossa
+known as the concha (fig. 1, d), and from the anterior part of this the
+meatus passes inward into the skull. Overlapping the meatus from in
+front is a flap called the tragus, and below and behind this is another
+smaller flap, the antitragus. The lower part of the pinna is the lobule
+(e), which contains no cartilage. On the cranial surface of the pinna
+elevations correspond to the concha and to the fossae of the helix and
+antihelix. The pinna can be slightly moved by the anterior, superior and
+posterior auricular muscles, and in addition to these there are four
+small intrinsic muscles on the external surface, known as the helicis
+major and minor, the tragicus and the antitragicus, and two on the
+internal surface called the obliquus and transversus. The external
+auditory meatus (fig. 1, n) is a tube running at first forward and
+upward, then a little backward and then forward and slightly downward;
+of course all the time it is also running inward until the tympanic
+membrane is reached. The tube is about an inch long, its outer third
+being cartilaginous and its inner two-thirds bony. It is lined by skin
+in its whole length, the sweat glands of which are modified to secrete
+the wax or cerumen.
+
+[Illustration: FIG. 1.--The Ear as seen in Section.
+
+  a, Helix.                     m, Tip of petrous process.
+  b, Antitragus.                n, External auditory meatus.
+  c, Antihelix.                 o, Membrana tympani.
+  d, Concha.                    p, Tympanum.
+  e, Lobule.                    1, points to malleus.
+  f, Mastoid process.           2, to incus.
+  g, Portio dura.               3, to stapes.
+  h, Styloid process.           4, to cochlea.
+  k, Internal carotid artery.   5, 6, 7, the three semicircular canals.
+  l, Eustachian tube.           8 and 9, facial and auditory nerves.]
+
+The middle ear or tympanum (fig. 1, p) is a small cavity in the temporal
+bone, the shape of which may perhaps be realized by imagining a hock
+bottle subjected to lateral pressure in such a way that its circular
+section becomes triangular, the base of the triangle being above. The
+neck of the bottle, also laterally compressed, will represent the
+Eustachian tube (fig. 1, l), which runs forward, inward and downward, to
+open into the naso-pharynx, and so admits air into the tympanum. The
+bottom of the bottle will represent the posterior wall of the tympanum,
+from the upper part of which an opening leads backward into the mastoid
+antrum and so into the air-cells of the mastoid process. Lower down is a
+little pyramid which transmits the stapedius muscle, and at the base of
+this is a small opening known as the iter chordae posterius, for the
+chorda tympani to come through from the facial nerve. The roof is formed
+by a very thin plate of bone, called the tegmen tympani, which separates
+the cavity from the middle fossa of the skull. Below the roof the upper
+part of the tympanum is somewhat constricted off from the rest, and to
+this part the term "attic" is often applied. The floor is a mere groove
+formed by the meeting of the external and internal walls. The outer wall
+is largely occupied by the tympanic membrane (fig. 1, o), which entirely
+separates the middle ear from the external auditory meatus; it is
+circular, and so placed that it slopes from above, downward and inward,
+and from behind, forward and inward. Externally it is lined by skin,
+internally by mucous membrane, while between the two is a firm fibrous
+membrane, convex inward about its centre to form the umbo. Just in front
+of the membrane on the outer wall is the Glaserian fissure leading to
+the glenoid cavity, and close to this is the canal of Huguier for the
+chorda tympani nerve. The inner wall shows a promontory caused by the
+cochlea and grooved by the tympanic plexus of nerves; above and behind
+it is the fenestra ovalis, while below and behind the fenestra rotunda
+is seen, closed by a membrane. Curving round, above and behind the
+promontory and fenestrae, is a ridge caused by the aqueductus Fallopii
+or canal for the facial nerve. The whole tympanum is about half an inch
+from before backward, and half an inch high, and is spanned from side to
+side by three small bones, of which the malleus (fig. 1, 1) is the most
+external. This is attached by its handle to the umbo of the tympanic
+membrane, while its head lies in the attic and articulates posteriorly
+with the upper part of the next bone or incus (fig. 1, 2). The long
+process of the incus runs downward and ends in a little knob called the
+os orbiculare, which is jointed on to the stapes or stirrup bone (fig.
+1, 3). The two branches of the stapes are anterior and posterior, while
+the footplate fits into the fenestra ovalis and is bound to it by a
+membrane. It will thus be seen that the stapes lies nearly at right
+angles to the long process of the incus. From the front of the malleus a
+slender process projects forward into the Glaserian fissure, while from
+the back of the incus the posterior process is directed backward and is
+attached to the posterior wall of the tympanum. These two processes form
+a fulcrum by which the lever action of the malleus and incus is brought
+about, so that when the handle of the malleus is pushed in by the
+membrane the head moves out; the top of the incus, attached to it, also
+moves out, and the os orbiculare moves in, and so the stapes is pressed
+into the fenestra ovalis. The stapedius and tensor tympanic muscles, the
+latter of which enters the tympanum in a canal just above the
+Eustachian tube to be attached to the malleus, modify the movements of
+the ossicles.
+
+The mucous membrane lining the tympanum is continuous through the
+Eustachian tube with that of the naso-pharynx, and is reflected on to
+the ossicles, muscles and chorda tympani nerve. It is ciliated except
+where it covers the membrana tympani, ossicles and promontory; here it
+is stratified.
+
+[Illustration: FIG. 2.--Diagram of the Membranous Labyrinth.
+
+  DC, Ductus cochlearis.
+  dr, Ductus reuniens.
+  S, Sacculus.
+  U, Utriculus.
+  dv, Ductus endolymphaticus.
+  SC, Semicircular canals.
+         (After Waldeyer.)]
+
+The internal ear or labyrinth consists of a bony and a membranous part,
+the latter of which is contained in the former. The bony labyrinth is
+composed of the vestibule, the semicircular canals and the cochlea. The
+vestibule lies just internal to the posterior part of the tympanum, and
+there would be a communication between the two, through the fenestra
+ovalis, were it not that the footplate of the stapes blocks the way. The
+inner wall of the vestibule is separated from the bottom of the internal
+auditory meatus by a plate of bone pierced by many foramina for branches
+of the auditory nerve (fig. 1, 9), while at the lower part is the
+opening of the aqueductus vestibuli, by means of which a communication
+is established with the posterior cranial fossa. Posteriorly the three
+semicircular canals open into the vestibule; of these the external (fig.
+1, 7) has two independent openings, but the superior and posterior (fig.
+1, 5 and 6) join together at one end and so have a common opening, while
+at their other ends they open separately. The three canals have
+therefore five openings into the vestibule instead of six. One end of
+each canal is dilated to form its ampulla. The superior semicircular
+canal is vertical, and the two pillars of its arch are nearly external
+and internal; the external canal is horizontal, its two pillars being
+anterior and posterior, while the convexity of the arch of the posterior
+canal is backward and its two pillars are superior and inferior.
+Anteriorly the vestibule leads into the cochlea (fig. 1, 4), which is
+twisted two and a half times round a central pillar called the modiolus,
+the whole cochlea forming a rounded cone something like the shell of a
+snail though it is only about 5 mm. from base to apex. Projecting from
+the modiolus is a horizontal plate which runs round it from base to apex
+like a spiral staircase; this is known as the lamina spiralis, and it
+stretches nearly half-way across the canal of the cochlea. At the summit
+it ends in a little hook named the hamulus. The modiolus is pierced by
+canals which transmit branches of the auditory nerve to the lamina
+spiralis.
+
+[Illustration: FIG. 3.--cl, Columnar cells covering the crista acustica;
+p, peripheral, and c, central processes of auditory cells; n, nerve
+fibres. (After Ruedinger.)]
+
+The membranous labyrinth lies in the bony labyrinth, but does not fill
+it; between the two is the fluid called perilymph, while inside the
+membranous labyrinth is the endolymph. In the bony vestibule lie two
+membranous bags, the saccule (fig. 2, S) in front, and the utricle (fig.
+2, U) behind; each of these has a special patch or macula to which twigs
+of the auditory nerve are supplied, and in the mucous membrane of which
+specialized hair cells are found (fig. 3, p).
+
+Attached to the maculae are crystals of carbonate of lime called
+otoconia. The membranous semicircular canals are very much smaller in
+section than the bony; in the ampulla of each is a ridge, the crista
+acustica, which is covered by a mucous membrane containing sensory hair
+cells like those in the maculae. All the canals open into the utricle.
+From the lower part of the saccule a small canal called the ductus
+endolymphaticus (fig. 2, dv) runs into the aqueductus vestibuli; it is
+soon joined by a small duct from the utricle, and ends, close to the
+dura mater of the posterior fossa of the cranium, as the saccus
+endolymphaticus, which may have minute perforations through which the
+endolymph can pass. Anteriorly the saccule communicates with the
+membranous cochlea or scala media by a short ductus reuniens (fig. 2,
+dr). A section through each turn of the cochlea shows the bony lamina
+spiralis, already noticed, which is continued right across the canal by
+the basilar membrane (fig. 4, bm), thus cutting the canal into an upper
+and lower half and connected with the outer wall by the strong spiral
+ligament (fig. 4, sl). Near the free end of the lamina spiralis another
+membrane called the membrane of Reissner (fig. 4, mR) is attached, and
+runs outward and upward to the outer wall, taking a triangular slice out
+of the upper half of the section. There are now three canals seen in
+section, the upper of which is the scala vestibuli (fig. 4, SV), the
+middle and outer the scala media, ductus cochlearis or true membranous
+cochlea (fig. 4, DC), while the lower is the scala tympani (fig. 4, ST).
+The scala vestibuli and scala tympani communicate at the apex of the
+cochlea by an opening known as the helicotrema, so that the perilymph
+can here pass from one canal to the other. At the base of the cochlea
+the perilymph in the scala vestibuli is continuous with that in the
+vestibule, but that in the scala tympani bathes the inner surface of the
+membrane stretched across the fenestra rotunda, and also communicates
+with the subarachnoid space through the aqueductus cochleae, which opens
+into the posterior cranial fossa. The scala media containing endolymph
+communicates, as has been shown, with the saccule through the canalis
+reuniens, while, at the apex of the cochlea, it ends in a blind
+extremity of considerable morphological interest called the lagena.
+
+[Illustration: FIG. 4.--Transverse Section through the Tube of the
+Cochlea.
+
+  m, Modiolus.                 bm, Basilar membrane.
+  0, Outer wall of cochlea.    cs, Crista spiralis.
+  SV, Scala vestibuli.         sl, Spiral ligament.
+  ST, Scala tympani.           sg, Spiral ganglion of auditory nerve.
+  DC, Ductus cochlearis.       oc, Organ of Corti.
+  mR, Membrane of Reissner.]
+
+The scala media contains the essential organ of hearing or organ of
+Corti (fig. 4, oc), which lies upon the inner part of the basilar
+membrane; it consists of a tunnel bounded on each side of the inner and
+outer rods of Corti; on each side of these are the inner and outer hair
+cells, between the latter of which are found the supporting cells of
+Deiters. Most externally are the large cells of Hensen. A delicate
+membrane called the lamina reticularis covers the top of all these, and
+is pierced by the hairs of the hair cells, while above this is the loose
+membrana tectoria attached to the periosteum of the lamina spiralis,
+near its tip, internally, and possibly to some of Deiter's cells
+externally. The cochlear branch of the auditory nerve enters the lamina
+spiralis, where a spiral ganglion (fig. 4, sg) is developed on it; after
+this it is distributed to the inner and outer hair cells.
+
+[Illustration: FIG. 5.--Transverse Section of Corti's Organ from the
+Central Coil of Cochlea (Retzius).
+
+(From R. Howden--Cunningham's _Text-Book of Anatomy_.)]
+
+  For further details see _Text-Book of Anatomy_, edited by D.J.
+  Cunningham (Edinburgh, 1906); Quain's _Elements of Anatomy_ (London,
+  1893); Gray's _Anatomy_ (London, 1905); _A Treatise on Anatomy_,
+  edited by H. Morris (London, 1902); _A Text-Book of Human Anatomy_, by
+  A. Macalister (London, 1889).
+
+_Embryology._--The pinna is formed from six tubercles which appear round
+the dorsal end of the hyomandibular cleft or, more strictly speaking,
+pouch. Those for the tragus and anterior part of the helix belong to the
+first or mandibular arch, while those for the antitragus, antihelix and
+lobule come from the second or hyoid arch. The tubercle for the helix is
+dorsal to the end of the cleft where the two arches join. The external
+auditory meatus, tympanum and Eustachian tube are remains of the
+hyomandibular cleft, the membrana tympani being a remnant of the cleft
+membrane and therefore lined by ectoderm outside and entoderm inside.
+The origin of the ossicles is very doubtful. H. Gadow's view, which is
+one of the latest, is that all three are derived from the hyomandibular
+plate which connects the dorsal ends of the hyoid and mandibular bars
+(_Anatomischer Anzeiger_, Bd. xix., 1901, p. 396). Other papers which
+should be consulted are those of E. Gaupp, _Anatom. Hefte, Ergebnisse_,
+Bd. 8, 1898, p. 991, and J.A. Hammar, _Archiv f. mikr. Anat._ lix.,
+1902. These papers will give a clue to the immense literature of the
+subject. The internal ear first appears as a pit from the cephalic
+ectoderm, the mouth of which in Man and other mammals closes up, so that
+a pear-shaped cavity is left. The stalk of the pear which is nearest the
+point of invagination is called the recessus labyrinthi, and this, after
+losing its connexion with the surface of the embryo, grows backward
+toward the posterior cranial fossa and becomes the ductus
+endolymphaticus. The lower part of the vesicle grows forward and becomes
+the cochlea, while from the upper part three hollow circular plates grow
+out, the central parts of which disappear, leaving the margin as the
+semicircular canals. Subsequently constrictions appear in the vesicle
+marking off the saccule and utricle. From the surrounding mesoderm the
+petrous bone is formed by a process of chondrification and ossification.
+
+  See W. His, Junr., _Archiv f. Anat. und Phys._, 1889, supplement, p.
+  1; also Streeter, _Am. Journ. of Anat._ vi., 1907.
+
+_Comparative Anatomy._--The ectodermal inpushing of the internal ear has
+probably a common origin with the organs of the lateral line of fish. In
+the lower forms the ductus endolymphaticus retains its communication
+with the exterior on the dorsum of the head, and in some Elasmobranchs
+the opening is wide enough to allow the passage of particles of sand
+into the saccule. It is probable that this duct is the same which,
+taking a different direction and losing its communication with the skin,
+abuts on the posterior cranial fossa of higher forms (see Rudolf Krause,
+"Die Entwickelung des Aq. vestibuli seu d. Endelymphaticus," _Anat.
+Anzeiger_, Bd. xix., 1901, p. 49). In certain Teleostean fishes the swim
+bladder forms a secondary communication with the internal ear by means
+of special ossicles (see G. Ridewood, _Journ. Anat. & Phys._ vol.
+xxvi.). Among the Cyclostomata the external semicircular canals are
+wanting; Petromyzon has the superior and posterior only, while in Myxine
+these two appear to be fused so that only one is seen. In higher types
+the three canals are constant. Concretions of carbonate of lime are
+present in the internal ears of almost all vertebrates; when these are
+very small they are called otoconia, but when, as in most of the
+teleostean fishes, they form huge concretions, they are spoken of as
+otoliths. One shark, Squatina, has sand instead of otoconia (C. Stewart,
+_Journ. Linn. Society_, xxix. 409). The utricle, saccule, semicircular
+canals, ductus endolymphaticus and a short lagena are the only parts of
+the ear present in fish.
+
+The Amphibia have an important sensory area at the base of the lagena
+known as the macula acustica basilaris, which is probably the first
+rudiment of a true cochlea. The ductus endolymphaticus has lost its
+communication with the skin, but it is frequently prolonged into the
+skull and along the spinal canal, from which it protrudes, through the
+intervertebral foramina, bulging into the coelom. This is the case in
+the common frog (A. Coggi, _Anat. Anz._ 5. Jahrg., 1890, p. 177). In
+this class the tympanum and Eustachian tube are first developed; the
+membrana tympani lies flush with the skin of the side of the head, and
+the sound-waves are transmitted from it to the internal ear by a single
+bony rod--the columella.
+
+In the Reptilia the internal ear passes through a great range of
+development. In the Chelonia and Ophidia the cochlea is as rudimentary
+as in the Amphibia, but in the higher forms (Crocodilia) there is a
+lengthened and slightly twisted cochlea, at the end of which the lagena
+forms a minute terminal appendage. At the same time indications of the
+scalae tympani and vestibuli appear. As in the Amphibia the ductus
+endolymphaticus sometimes extends into the cranial cavity and on into
+other parts of the body. Snakes have no tympanic membrane. In the birds
+the cochlea resembles that of the crocodiles, but the posterior
+semicircular canal is above the superior where they join one another. In
+certain lizards and birds (owls) a small fold of skin represents the
+first appearance of an external ear. In the monotremes the internal ear
+is reptilian in its arrangement, but above them the mammals always have
+a spirally twisted cochlea, the number of turns varying from one and a
+half in the Cetacea to nearly five in the rodent _Coelogenys_. The
+lagena is reduced to a mere vestige. The organ of Corti is peculiar to
+mammals, and the single columella of the middle ear is replaced by the
+three ossicles already described in Man (see Alban Doran, "Morphology of
+the Mammalian Ossicula auditus," _Proc. Linn. Soc._, 1876-1877, xiii.
+185; also _Trans. Linn. Soc._ 2nd Ser. Zool. i. 371). In some mammals,
+especially Carnivora, the middle ear is enlarged to form the tympanic
+bulla, but the mastoid cells are peculiar to Man.
+
+  For further details see G. Retzius, _Das Gehoerorgan der Wirbelthiere_
+  (Stockholm, 1881-1884); Catalogue of the Museum of the R. College of
+  Surgeons--Physiological Series, vol. iii. (London, 1906); R.
+  Wiedersheim's _Vergleichende Anatomie der Wirbeltiere_ (Jena, 1902).
+       (F. G. P.)
+
+
+DISEASES OF THE EAR
+
+Modern scientific aural surgery and medicine (commonly known as Otology)
+dates from the time of Sir William Wilde of Dublin (1843), whose work
+marked a great advance in the application of anatomical, physiological
+and therapeutical knowledge to the study of this organ. Less noticeable
+contributions to the subject had not long before been made by Saunders
+(1827), Kramer (1833), Pilcher (1841) and Yearsley (1841). The next
+important event in the history of otology was the publication of J.
+Toynbee's book in 1860 containing his valuable anatomical and
+pathological observations. Von Troeltsch of Wuerzburg, following on the
+lines of Wilde and Toynbee, produced two well-known works in 1861 and
+1862, laying the foundation of the study in Germany. In that country and
+in Austria he was followed by Hermann Schwartze, Politzer, Gruber,
+Weber-Liel, Ruedinger, Moos and numerous others. France produced Itard,
+de la Charriere, Meniere, Loewenberg and Bonnafont; and Belgium, Charles
+Delstanche, father and son. In Great Britain the work was carried on by
+James Hinton (1874), Peter Allen (1871), Patterson Cassells and Sir
+William Dalby. In America we may count among the early otologists Edward
+H. Clarke (1858), D.B. St John Roosa, H. Knapp, Clarence J. Blake,
+Albert H. Buck and Charles Burnett. Other workers all over the world are
+too numerous to mention.
+
+_Various Diseases and Injuries._--Diseases of the ear may affect any of
+the three divisions, the external, middle or internal ear. The commoner
+affections of the _auricle_ are eczema, various tumours (simple and
+malignant), and serous and sebaceous cysts. Haematoma auris
+(othaematoma), or effusion of blood into the auricle, is often due to
+injury, but may occur spontaneously, especially in insane persons. The
+chief diseases of the _external auditory canal_ are as follows:--impacted
+cerumen (or wax), circumscribed (or furuncular) inflammation, diffuse
+inflammation, strictures due to inflammatory affections, bony growths,
+fungi (otomycosis), malignant disease, caries and necrosis, and foreign
+bodies.
+
+Diseases of the _middle ear_ fall into two categories, suppurative and
+non-suppurative (i.e. with and without the formation of pus).
+Suppurative inflammation of the middle ear is either acute or chronic,
+and is in either case accompanied by perforation of the drum head and
+discharge from the ear. The chief importance of these affections, in
+addition to the symptoms of pain, deafness, discharge, &c., is the
+serious complications which may ensue from their neglect, viz. aural
+polypi, caries and necrosis of the bone, affections of the mastoid
+process, including the mastoid antrum, paralysis of the facial nerve,
+and the still more serious intracranial and vascular infective diseases,
+such as abscess in the brain (cerebrum or cerebellum), meningitis, with
+subdural and extradural abscesses, septic thrombosis of the sigmoid and
+other venous sinuses, and pyaemia. It is owing to the possibility of
+these complications that life insurance companies usually, and rightly,
+inquire as to the presence of ear discharge before accepting a life.
+Patterson Cassells of Glasgow urged this special point as long ago as
+1877. Acute suppurative disease of the middle ear is often due to the
+exanthemata, scarlatina, measles and smallpox, and to bathing and
+diving. It may also be caused by influenza, diphtheria and pulmonary
+phthisis.
+
+Non-suppurative disease of the middle ear may be acute or chronic. In
+the acute form the inflammation is less violent than in the acute
+suppurative inflammation, and is rarely accompanied by perforation.
+Chronic non-suppurative inflammation may be divided into the moist form,
+in which the symptoms are improved by inflation of the tympanum through
+the Eustachian tube, and the dry form (including sclerosis), which is
+more intractable and in which this procedure has little or no beneficial
+effect. Diseases of the _internal ear_ may be primary or secondary to an
+affection of the tympanum or to intracranial disease.
+
+Injuries to any part of the ear may occur, among the commoner being
+injuries to the auricle, rupture of the drum head (from explosions,
+blows on the ear or the introduction of sharp bodies into the ear
+canal), and injuries from fractured skull. Congenital malformations of
+the ear are most frequently met with in the auricle and external canal.
+
+_Methods of Examination._--The methods of examining the ear are roughly
+threefold:--(1) Testing the hearing with watch, voice and tuning-fork.
+The latter is especially used to distinguish between disease of the
+middle ear (conducting apparatus) and that of the internal ear
+(perceptive apparatus). Our knowledge of the subject has been brought to
+its present state by the labours of many observers, notably Weber,
+Rinne, Schwabach, Lucae and Gelle. (2) Examination of the canal and
+drum-head with speculum and reflector, introduced by Kramer, Wilde and
+von Troeltsch. (3) Examination of the drum-cavity through the Eustachian
+tube by the various methods of inflation.
+
+_Symptoms._--The chief symptoms of ear diseases are deafness, noises in
+the ear (tinnitus aurium), giddiness, pain and discharge. Deafness (or
+other disturbance of hearing) and noises may occur from disease in
+almost any part of the ear. Purulent discharge usually comes from the
+middle ear. Giddiness is more commonly associated with affections of the
+internal ear.
+
+_Treatment._--Ear diseases are treated on ordinary surgical and medical
+lines, due regard being had to the anatomical and physiological
+peculiarities of this organ of sense, and especially to its close
+relationship, on the one hand to the nose and naso-pharynx, and on the
+other hand to the cranium and its contents. The chief advance in aural
+surgery in recent years has been in the surgery of the mastoid process
+and antrum. The pioneers of this work were H. Schwartze of Halle, and
+Stacke of Erfurt, who have been followed by a host of workers in all
+parts of the world. This development led to increased attention being
+paid to the intracranial complications of suppurative ear disease, in
+the treatment of which great strides have been made in the last few
+years.
+
+_Effects of Diseases of the Nose on the Ear._--The influence of diseases
+of the nose and naso-pharynx on ear diseases was brought out by
+Loewenberg of Paris, Voltolini of Breslau, and especially by Wilhelm
+Meyer of Copenhagen, the discoverer of adenoid vegetations of the
+naso-pharynx ("adenoids"), who recognized the great importance of this
+disease and gave an inimitable account of it in the _Trans. of the Royal
+Medical and Chirurgical Society of London_, 1870, and the _Archiv fuer
+Ohrenheilkunde_, 1873. Adenoid vegetations, which consist of an abnormal
+enlargement of Luschka's tonsil in the vault of the pharynx, frequently
+give rise to ear disease in children, and, if not attended to, lay the
+foundation of nasal and ear troubles in after life. They are often
+associated with enlargement of the faucial tonsils.
+
+  _Journals._--In 1864 the _Archiv fuer Ohrenheilkunde_ was started by
+  Politzer and Schwartze, and, in 1867, the _Monatsschrift fuer
+  Ohrenheilkunde_ (a monthly publication) was founded by Voltolini,
+  Gruber, Weber-Liel and Ruedinger. Appearing first as the _Archives of
+  Ophthalmology and Otology_, simultaneously in English and German, in
+  1869, the _Archives of Otology_ became a separate publication under
+  the editorship of Knapp, Moos and Roosa in 1879. Amongst other
+  journals now existing are _Annales des maladies de l'oreille et du
+  larynx_ (Paris), _Journal of Laryngology_ (London), _Centralblatt fuer
+  Ohrenheilkunde_ (Leipzig), &c.
+
+  _Societies._--The earliest society formed was the American Otological
+  Society (1868), which held annual meetings and published yearly
+  transactions. Flourishing societies for the study of otology
+  (sometimes combined with laryngology) exist in almost all civilized
+  countries, and they usually publish transactions consisting of
+  original papers and cases. The Otological Society of the United
+  Kingdom was founded in 1900.
+
+  _International Congresses._--International Otological congresses have
+  been held at intervals of about four years at New York, Milan, Basel,
+  Brussels, Florence, London and Bordeaux (1904). The proceedings of the
+  congresses appear as substantial volumes.
+
+  _Hospitals._--The earliest record of a public institution for the
+  treatment of ear diseases is a Dispensary for Diseases of the Eye and
+  Ear in London, started by Saunders and Cooper, which existed in 1804;
+  the aural part, however, was soon closed, so that the actual oldest
+  institution appears to be the Royal Ear Hospital, London, which was
+  founded by Curtis in 1816. Four years later there was started the New
+  York Eye and Ear Infirmary. At the present time in every large town of
+  Europe and America ear diseases are treated either in separate
+  departments of general hospitals or in institutions especially devoted
+  to the purpose.
+
+  For a history of otology from the earliest times refer to _A Practical
+  Treatise on the Diseases of the Ear_, by D.B. St John Roosa, M.D.,
+  LL.D. (6th edition, New York, 1885), and for a general account of the
+  present state of otological science to _A Text-Book of the Diseases of
+  the Ear for Students and Practitioners_, by Professor Dr Adam
+  Politzer, transl. by Milton J. Ballin, Ph.B., M.D., and Clarence J.
+  Heller, M.D. (4th edition, London, 1902).     (E. C. B.*)
+
+
+
+
+EARL, a title and rank of nobility (corresponding to Lat. _comes_; Fr.
+_comte_), now the third in order of the British peerage, and accordingly
+intervening between marquess and viscount. Earl, however, is the oldest
+title and rank of English nobles, and was the highest until the year
+1337, when the Black Prince was created duke of Cornwall by Edward III.
+
+The nature of a modern earldom is readily understood, since it is a rank
+and dignity of nobility which, while it confers no official power or
+authority, is inalienable, indivisible, and descends in regular
+succession to all the heirs under the limitation in the grant until, on
+their failure, it becomes extinct.
+
+The title is of Scandinavian origin, and first appears in England under
+Canute as _jarl_, which was englished as _eorl_. Like the _ealdorman_,
+whose place he took, the _eorl_ was a great royal officer, who might be
+set over several counties, but who presided separately in the county
+court of each with the bishop of the diocese. Although there were counts
+in Normandy before the Norman Conquest, they differed in character from
+the English earls, and the earl's position appears to have been but
+slightly modified by the Conquest. He was still generally entitled to
+the "third penny" of the county, but his office tended, under Norman
+influence, to become an hereditary dignity and his sphere was restricted
+by the Conqueror to a single county. The right to the "third penny" is a
+question of some obscurity, but its possession seems to have been deemed
+the distinctive mark of an earl, while the girding with "the sword of
+the county" formed the essential feature in his creation or investiture,
+as it continued to do for centuries later. The fact that every earl was
+the earl of a particular county has been much obscured by the loose
+usage of early times, when the style adopted was sometimes that of the
+noble's surname (e.g. the Earls Ferrers), sometimes that of his chief
+seat (e.g. the Earls of Arundel), and sometimes that of the county.
+Palatine earldoms, or palatinates, were those which possessed _regalia_,
+i.e. special privileges delegated by the crown. The two great examples,
+which dated from Norman times, were Chester and Durham, where the earl
+and the bishop respectively had their own courts and jurisdiction, and
+were almost petty sovereigns.
+
+The earliest known charter creating an earl is that by which Stephen
+bestowed on Geoffrey de Mandeville, in or about 1140, the earldom of
+Essex as an hereditary dignity. Several other creations by Stephen and
+the empress Maud followed in quick succession. From at least the time of
+the Conquest the earl had a double character; he was one of the
+"barons," or tenants in chief, in virtue of the fief he held of the
+crown, as well as an earl in virtue of his "belting" (with the sword)
+and his "third penny" of the county. His fief would descend to the heirs
+of his body; and the earliest charters creating earldoms were granted
+with the same "limitation." The dignity might thus descend to a woman,
+and, in that case, like the territorial fief, it would be held by her
+husband, who might be summoned to parliament in right of it. The earldom
+of Warwick thus passed through several families till it was finally
+obtained, in 1449, by the Kingmaker, who had married the heiress of the
+former earls. But in the case of "co-heiresses" (more daughters than
+one), the king determined which, if any, should inherit the dignity.
+
+The 14th century saw some changes introduced. The earldom of March,
+created in 1328, was the first that was not named from a county or its
+capital town. Under Edward III. also an idea appears to have arisen that
+earldoms were connected with the tenure of lands, and in 1337 several
+fresh ones were created and large grants of lands made for their
+support. The first earldom granted with limitation to the heirs male of
+the grantee's body was that of Nottingham in 1383. Another innovation
+was the grant of the first earldom for life only in 1377. The girding
+with the sword was the only observance at a creation till the first year
+of Edward VI., when the imposition of the cap of dignity and a circlet
+of gold was added. Under James I. the patent of creation was declared to
+be sufficient without any ceremony. An earl's robe of estate has three
+bars of ermine, but possibly it had originally four.
+
+Something should be said of anomalous earldoms with Norman or Scottish
+styles. The Norman styles originated either under the Norman kings or at
+the time of the conquest of Normandy by the house of Lancaster. To the
+former period belonged that of Aumale, which successive fresh creations,
+under the Latinized form "Albemarle" have perpetuated to the present day
+(see ALBEMARLE, EARLS AND DUKES OF). The so-called earls of Eu and of
+Mortain, in that period, were really holders of Norman _comtes_. Henry
+V. and his son created five or six, it is said, but really seven at
+least, Norman countships or earldoms, of which Harcourt (1418), Perche
+(1419), Dreux (1427) and Mortain (? 1430) were bestowed on English
+nobles, Eu (1419), and Tankerville (1419) on English commoners, and
+Longueville (1419) on a foreigner, Gaston de Foix. Of these the earldom
+of "Eu" was assumed by the earls of Essex till the death of Robert, the
+parliament's general (1646), while the title of Tankerville still
+survives under a modern creation (1714). An anomalous royal licence of
+1661 permitted the earl of Bath to use the title of earl of Corbeil by
+alleged hereditary right. Of Scottish earldoms recognized in the English
+parliament the most remarkable case is that of the Lords Umfraville, who
+were summoned for three generations (1297-1380), as earls of Angus;
+Henry, Lord Beaumont, also was summoned as earl of Buchan from 1334 to
+1339.
+
+The earldom of Chester is granted to the princes of Wales on their
+creation, and the Scottish earldom of Carrick is held by the eldest son
+of the sovereign under act of parliament.
+
+The premier earldom is that of Arundel (q.v.), but as this is at present
+united with the dukedom of Norfolk, the oldest earldom not merged in a
+higher title is that of Shrewsbury (1442), the next in seniority being
+Derby (1485), and Huntingdon (1529). These three have been known as "the
+catskin earls," a term of uncertain origin. The ancient earldom of
+Wiltshire (1397) was unsuccessfully claimed in 1869 by Mr Scrope of
+Danby, and that of Norfolk (1312), in 1906, by Lord Mowbray and
+Stourton.
+
+The premier earldom of Scotland as recognized by the Union Roll (1707),
+is that of Crawford, held by the Lindsays since its creation in 1398;
+but it is not one of the ancient "seven earldoms." The Decreet of
+Ranking (1606) appears to have recognized the earldom of Sutherland as
+the most ancient in virtue of a charter of 1347, but the House of Lords'
+decision of 1771 recognized it as having descended from at least the
+year 1275, and it may be as old as 1228. It is at present united with
+the dukedom of Sutherland. The original "seven earldoms" (of which it
+was one) represented seven provinces, each of which was under a
+"_mormaer_." This Celtic title was rendered "_jarl_" by the Norsemen,
+and under Alexander I. (c. 1115) began to be replaced by earl (_comes_),
+owing to Anglo-Norman influence, which also tended to make these
+earldoms less official and more feudal.
+
+In Ireland the duke of Leinster is, as earl of Kildare, premier earl as
+well as premier duke.
+
+An earl is "Right Honourable," and is styled "My Lord." His eldest son
+bears his father's "second title," and therefore, that second title
+being in most cases a viscounty, he generally is styled "Viscount";
+where, as with Devon and Huntingdon, there is no second title, one may
+be assumed for convenience; under all circumstances, however, the eldest
+son of an earl takes precedence immediately after the viscounts. The
+younger sons of earls are "Honourable," but all their daughters are
+"Ladies." In formal documents and instruments, the sovereign, when
+addressing or making mention of any peer of the degree of an earl,
+usually designates him "trusty and well-beloved cousin,"--a form of
+appellation first adopted by Henry IV., who either by descent or
+alliance was actually related to every earl and duke in the realm. The
+wife of an earl is a countess; she is "Right Honourable," and is styled
+"My Lady." For the earl's coronet see CROWN AND CORONET.
+
+  See Lord's _Reports on the Dignity of a Peer_; Pike's _Constitutional_
+  _History of the House of Lords_; Selden's _Titles of Honour_; G.E.
+  C(okayne)'s _Complete Peerage_; Round's _Geoffrey de Mandeville_.
+       (J. H. R.)
+
+
+
+
+EARLE, JOHN (c. 1601-1665), English divine, was born at York about 1601.
+He matriculated at Christ Church, Oxford, but migrated to Merton, where
+he obtained a fellowship. In 1631 he was proctor and also chaplain to
+Philip, earl of Pembroke, then chancellor of the university, who
+presented him to the rectory of Bishopston in Wiltshire. His fame
+spread, and in 1641 he was appointed chaplain and tutor to Prince
+Charles. In 1643 he was elected one of the Assembly of Divines at
+Westminster, but his sympathies with the king and with the Anglican
+Church were so strong that he declined to sit. Early in 1643 he was
+chosen chancellor of the cathedral of Salisbury, but of this preferment
+he was soon deprived as a "malignant." After Cromwell's great victory at
+Worcester, Earle went abroad, and was named clerk of the closet and
+chaplain to Charles II. He spent a year at Antwerp in the house of Isaac
+Walton's friend, George Morley, who afterwards became bishop of
+Winchester. He next joined the duke of York (James II.) at Paris,
+returning to England at the Restoration. He was at once appointed dean
+of Westminster, and in 1661 was one of the commissioners for revising
+the liturgy. He was on friendly terms with Richard Baxter. In November
+1662 he was consecrated bishop of Worcester, and was translated, ten
+months later, to the see of Salisbury, where he conciliated the
+nonconformists. He was strongly opposed to the Conventicle and Five Mile
+Acts. During the great plague Earle attended the king and queen at
+Oxford, and there he died on the 17th of November 1665.
+
+Earle's chief title to remembrance is his witty and humorous work
+entitled _Microcosmographie, or a Peece of the World discovered, in
+Essayes and Characters_, which throws light on the manners of the time.
+First published anonymously in 1628, it became very popular, and ran
+through ten editions in the lifetime of the author. The style is quaint
+and epigrammatic; and the reader is frequently reminded of Thomas Fuller
+by such passages as this: "A university dunner is a gentlemen follower
+cheaply purchased, for his own money has hyr'd him." Several reprints of
+the book have been issued since the author's death; and in 1671 a French
+translation by J. Dymock appeared with the title of _Le Vice ridicule_.
+Earle was employed by Charles II. to make the Latin translation of the
+_Eikon Basilike_, published in 1649. A similar translation of R.
+Hooker's _Ecclesiastical Polity_ was accidentally destroyed.
+
+"Dr Earle," says Lord Clarendon in his _Life_, "was a man of great piety
+and devotion, a most eloquent and powerful preacher, and of a
+conversation so pleasant and delightful, so very innocent, and so very
+facetious, that no man's company was more desired and loved. No man was
+more negligent in his dress and habit and mien, no man more wary and
+cultivated in his behaviour and discourse. He was very dear to the Lord
+Falkland, with whom he spent as much time as he could make his own."
+
+  See especially Philip Bliss's edition of the _Microcosmographie_
+  (London, 1811), and E. Arber's Reprint (London, 1868).
+
+
+
+
+EARLE, RALPH (1751-1801), American historical and portrait painter, was
+born at Leicester, Massachusetts, on the 11th of May 1751. Like so many
+of the colonial craftsmen, Earle was self-taught, and for many years was
+an itinerant painter. He went with the Governor's Guard to Lexington and
+made battle sketches, from which in 1775 he painted four scenes,
+engraved by Amos Doolittle, which are probably the first historical
+paintings by an American. After the War of Independence, Earle went to
+London, entered the studio of Benjamin West, and painted the king and
+many notables. After his return to America in 1786 he made portraits of
+Timothy Dwight, Governor Caleb Strong, Roger Sherman, and other
+prominent men. He also painted a large picture of Niagara Falls. He died
+at Bolton, Connecticut, on the 16th of August 1801.
+
+
+
+
+EARL MARSHAL, in England, a functionary who ranks as the eighth of the
+great officers of state. He is the head of the college of arms, and has
+the appointment of the kings-of-arms, heralds and pursuivants at his
+discretion. He attends the sovereign in opening and closing the session
+of parliament, walking opposite to the lord great chamberlain on his or
+her right hand. It is his duty to make arrangements for the order of all
+state processions and ceremonials, especially for coronations and royal
+marriages and funerals. Like the lord high constable he rode into
+Westminster Hall with the champion after a coronation, till the
+coronation banquet was abandoned, taking his place on the left hand, and
+with the lord great chamberlain he assists at the introduction of all
+newly-created peers into the House of Lords.
+
+The marshal appears in the feudal armies to have been in command of the
+cavalry under the constable, and to have in some measure superseded him
+as master of the horse in the royal palace. He exercised joint and
+co-ordinate jurisdiction with the constable in the court of chivalry,
+and afterwards became the sole judge of that tribunal till its
+obsolescence. The marshalship of England was formerly believed to have
+been inherited from the Clares by the Marshal family, who had only been
+marshals of the household. It was held, however, by the latter family,
+as the office of chief (_magister_) marshal, as early as the days of
+Henry I. Through them, under Henry III., it passed to the Bigods, as
+their eldest co-heirs. In 1306 it fell to the crown on the death of the
+last Bigod, earl of Norfolk, who had made Edward I. his heir, and in
+1316 it was granted by Edward II. to his own younger brother, Thomas "of
+Brotherton," earl of Norfolk. As yet the style of the office was only
+"marshal" although the last Bigod holder, being an earl, was sometimes
+loosely spoken of as the earl marshal. The office, having reverted to
+the crown, was granted out anew by Richard II., in 1385, to Thomas
+Mowbray, earl of Nottingham, the representative of Thomas "of
+Brotherton." In 1386 the style of "earl marshal" was formally granted to
+him in addition. After several attainders and partial restorations in
+the reigns of the Tudors and the Stuarts, the earl marshalship was
+granted anew to the Howards by Charles II. in 1672 and entailed on their
+male line, with many specific remainders and limitations, under which
+settlement it has regularly descended to the present duke of Norfolk.
+Its holders, however, could not execute the office until the Roman
+Catholic emancipation, and had to appoint deputies. The duke is styled
+earl marshal "and hereditary marshal of England," but the double style
+would seem to be an error, though the Mowbrays, with their double
+creation (1385, 1386) might have claimed it. His Grace appends the
+letters "E.M." to his signature, and bears behind his shield two batons
+crossed in saltire, the marshal's rod (_virga_) having been the badge of
+the office from Norman times. There appear to have been hereditary
+marshals of Ireland, but their history is not well ascertained. The
+Keiths were Great Marischals of Scotland from at least the days of
+Robert Bruce, and were created earls marischal in or about 1458, but
+lost both earldom and office by the attainder of George, the 10th earl,
+in 1716. (See also MARSHAL; STATE, GREAT OFFICERS OF.)
+
+  See "The Marshalship of England," in J.H. Round, _Commune of London
+  and Other Studies_ (London, 1899); G.E. C(okayne)'s _Complete
+  Peerage_.     (J. H. R.)
+
+
+
+
+EARLOM, RICHARD (1742-1822), English mezzotint engraver, was born and
+died in London. His natural faculty for art appears to have been first
+called into exercise by admiration for the lord mayor's state coach,
+just decorated by Cipriani. He tried to copy the paintings, and was sent
+to study under Cipriani. He displayed great skill as a draughtsman, and
+at the same time acquired without assistance the art of engraving in
+mezzotint. In 1765 he was employed by Alderman Boydell, then one of the
+most liberal promoters of the fine arts, to make a series of drawings
+from the pictures at Houghton Hall; and these he afterwards engraved in
+mezzotint. His most perfect works as engraver are perhaps the fruit and
+flower pieces after the Dutch artists Van Os and Van Huysum. Amongst his
+historical and figure subjects are--"Agrippina," after West; "Love in
+Bondage," after Guido Reni; the "Royal Academy," the "Embassy of
+Hyderbeck to meet Lord Cornwallis," and a "Tiger Hunt," the last three
+after Zoffany; and "Lord Heathfield," after Sir Joshua Reynolds. Earlom
+also executed a series of 200 facsimiles of the drawings and sketches
+of Claude Lorraine, which was published in 3 vols. folio, under the
+title of _Liber veritatis_ (1777-1819).
+
+
+
+
+EARLSTON (formerly ERCILDOUNE, of which it is a corruption), a parish
+and market town of Berwickshire, Scotland. Pop. (1901) 1049. It is
+situated on Leader Water in Lauderdale, 721/2 m. S.E. of Edinburgh by the
+North British railway branch line from Reston Junction to St Boswells,
+and about 4 m. N.E. of Melrose. When the place was a hamlet of rude huts
+it was called Arcioldun or "Prospect Fort," with reference to Black Hill
+(1003 ft.), on the top of which may yet be traced the concentric rings
+of the British fort by which it was crowned. It is said to be possible
+to make out the remains of the cave-dwellings of the Ottadeni, the
+aborigines of the district. In the 12th and 13th centuries the Lindsays
+and the earls of March and Dunbar were the chief baronial families. The
+particular link with the remote past, however, is the ivy-clad ruin of
+the ancient tower, "The Rhymer's Castle," the traditional residence of
+Thomas Learmont, commonly called Thomas of Ercildoune, or Thomas the
+Rhymer, poet and prophet, and friend of the Fairies, who was born here
+about 1225. Rhymer's Tower was crumbling to pieces, and its stones were
+being used in the erection of dykes, cottages and houses, when the
+Edinburgh Border Counties Association acquired the relic and surrounding
+lands in 1895, and took steps to prevent further spoliation and decay.
+The leading manufactures are ginghams, tweeds and shirtings, and the
+town is also an important agricultural centre, stock sales taking place
+at regular intervals and cattle and horse fairs being held every year.
+Some 3 m. away is the estate of Bemersyde, said to have been in the
+possession of the Haigs for nearly 1000 years. The prospect from
+Bemersyde Hill was Sir Walter Scott's favourite view. The castle at
+Bemersyde was erected in 1535 to secure the peace of the Border.
+
+
+
+
+EARLY, JUBAL ANDERSON (1816-1894), American soldier and lawyer, was born
+in Franklin county, Virginia, on the 3rd of November 1816, and graduated
+at the U.S. Military Academy in 1837. He served in the Seminole War of
+1837-38, after which he resigned in order to practise law in Franklin
+county, Va. He also engaged in state politics, and served in the Mexican
+War as a major of Virginia volunteers. He was strongly opposed to
+secession, but thought it his duty to conform to the action of his
+state. As a colonel in the Confederate army, he rendered conspicuous
+service at the first battle of Bull Run (q.v.). Promoted
+brigadier-general, and subsequently major-general, Early served
+throughout the Virginian campaigns of 1862-63, and defended the lines of
+Fredericksburg during the battle of Chancellorsville. At Gettysburg he
+commanded his division of Ewell's corps. In the campaign of 1864 Early,
+who had now reached the rank of lieutenant-general, commanded the
+Confederate forces in the Shenandoah Valley. The action of Lynchburg
+left him free to move northwards, his opponent being compelled to march
+away from the Valley. Early promptly utilized his advantage, crossed the
+Potomac, and defeated, on the Monocacy, all the troops which could be
+gathered to meet him. He appeared before the lines of Washington, put
+part of Maryland and Pennsylvania under contribution, and only retired
+to the Valley when threatened by heavy forces hurriedly sent up to
+Washington. He then fought a successful action at Winchester, reappeared
+on the Potomac, and sent his cavalry on a raid into Pennsylvania. A
+greatly superior army was now formed under General Sheridan to oppose
+Early. In spite of his skill and energy the Confederate leader was
+defeated in the battles of Winchester and Fisher's Hill. Finally, on the
+19th of October, after inflicting at first a severe blow upon the
+Federal army in its camps on Cedar Creek, he was decisively beaten by
+Sheridan. (See SHENANDOAH VALLEY CAMPAIGNS.) Waynesboro (March 1865) was
+his last fight, after which he was relieved from his command. General
+Early was regarded by many as the ablest soldier, after Lee and Jackson,
+in the Army of Northern Virginia, and one of the ablest in the whole
+Confederate army. That he failed to make headway against an army far
+superior in numbers, and led by a general of the calibre of Sheridan,
+cannot be held to prove the falsity of this judgment. After the peace
+he went to Canada, but in 1867 returned to resume the practice of law.
+For a time he managed in conjunction with General Beauregard the
+Louisiana lottery. He died at Lynchburg, Va., on the 2nd of March 1894.
+General Early was for a time president of the Southern Historical
+Society, and wrote, besides various essays and historical papers, _A
+Memoir of the Last Year of the War, &c._ (1867).
+
+
+
+
+EARLY ENGLISH PERIOD, in architecture, the term given by Rickman to the
+first pointed or Gothic style in England, nominally 1189-1307, which
+succeeded the Romanesque or Norman period towards the end of the 12th
+century, and developed into the Decorated period in the commencement of
+the 14th century. It is chiefly characterized by the almost universal
+employment of the pointed arch, not only in arches of wide span such as
+those of the nave arcade, but for doorways and windows. The actual
+introduction of the pointed arch took place at a much earlier date, as
+in the nave arcade of the Cistercian Abbey of Buildwas (1140), though
+the clerestory window above has semicircular arches. It is customary,
+therefore, to make allowance for a transitional epoch from the middle of
+the 12th century. Although the pointed arches used are sometimes
+equilateral and sometimes drop-arches, the lancet-arch is the most
+characteristic. The period is best recognized in England by the great
+depth given to the hollows of the mouldings, alternating with fillets
+and rolls, by the decoration of the hollows with the dog-tooth ornament,
+by the circular abacus of the capitals, and the employment of slender
+detached shafts of Purbeck marble which are attached to piers by
+circular moulded shaft-rings (Fr. _anneau_).
+
+The arches are sometimes cusped; circles with trefoils, quatrefoils,
+&c., are introduced into the tracery, and large rose windows in the
+transept or nave, as at Lincoln (1220). The conventional foliage
+decorating the capitals is of great beauty and variety, and extends to
+spandrils, bosses, &c. In the spandrils of the arches of the nave,
+transept or choir arcades, diaper work is occasionally found, as in the
+transept of Westminster Abbey. The latter is one of the chief examples
+of the period, to which must be added the cathedral of Salisbury (except
+the tower); the Galilee at Ely; nave and transept of Wells (1225-1240);
+nave of Lincoln; west front of Peterborough; and the minster at
+Beverley.     (R. P. S.)
+
+
+
+
+EARN, the name of a loch and river in Perthshire, Scotland. The loch,
+lying almost due east and west, is 61/2 m. long and {4/5} m. in maximum
+breadth, 287 ft. deep, with a mean depth of 138 ft., covers an area of
+nearly 4 sq. m., has a drainage basin of over 541/2 sq. m., and stands 317
+ft. above the sea. Its waters are said never to freeze. It discharges by
+the river Earn. The points of interest on its shores are Lochearnhead
+(at the southern extremity of Glen Ogle), which has a station on the
+Callander-Oban railway, and the ruins of St Blane's chapel; Edinample
+Castle, an old turreted mansion belonging to the marquess of
+Breadalbane, situated in well-wooded grounds near the pretty falls of
+the Ample; Ardvorlich House, the original of Darlinvarach in Scott's
+_Legend of Montrose_, and the village of St Fillans at the foot of the
+loch, once the terminus of the branch of the Caledonian railway from
+Perth. The river flows out of Loch Earn, pursues an eastward course with
+a gentle inclination towards the south, and reaches the Firth of Tay, 61/2
+m. below Perth, after a total run of 49 m. Its chief tributaries on the
+right are the Ruchil, Machany, Ruthven, May and Farg, and on the left,
+the Lednock and Turret. It is navigable by vessels of 50 tons as far up
+as Bridge of Earn, and is a notable fishing stream, abounding with
+salmon and trout, perch and pike being also plentiful. On the Lednock
+are the falls of the Devil's Cauldron and on the Turret and its feeders
+several graceful cascades. The principal places of interest on the banks
+of the Earn are Dunira, the favourite seat of Henry Dundas, 1st Viscount
+Melville, who took the title of his barony from the estate and to whose
+memory an obelisk was raised on the adjoining hill of Dunmore; the
+village of Comrie; the town of Crieff; the ruined castle of
+Innerpeffray, founded in 1610 by the 1st Lord Maderty, close to which is
+the library founded in 1691 by the 3rd Lord Maderty, containing some
+rare black-letter books and the Bible that belonged to the marquess of
+Montrose; Gascon Hall, now in ruins, but with traditions reaching back
+to the days of Wallace; Dupplin Castle, a fine Tudor mansion, seat of
+the earl of Kinnoull, who derives from it the title of his viscounty;
+Aberdalgie, Forgandenny and Bridge of Earn, a health resort situated
+amidst picturesque surroundings. Strathearn, as the valley of the Earn
+is called, extending from the loch to the Firth of Tay, is a beautiful
+and, on the whole, fertile tract, though liable at times to heavy
+floods. The earl of Perth is hereditary steward of Strathearn.
+
+
+
+
+EARNEST (probably a corruption of the obsolete _arles_ or _erles_,
+adapted from Lat. equivalent _arrha_, due to a confusion with the
+adjective "earnest," serious, O. Eng. _eornust_, cognate with Ger.
+_ernst_), the payment of a sum of money by the buyer of goods to the
+seller on the conclusion of a bargain as a pledge for its due
+performance. It is almost similar to the _arrha_ of the Roman law, which
+may be traced back in the history of legal institutions to a period when
+the validity of a contract depended not so much upon the real intention
+of the parties, as upon the due observance of a prescribed ceremony. But
+_earnest_ was never part payment, which _arrha_ might have been. Apart
+from its survival as a custom, its chief importance in English law is
+its recognition by the Statute of Frauds as giving validity to contracts
+for the sale of goods of a value exceeding L10 (see SALE OF GOODS). It
+is in that statute clearly distinguished from part payment, consequently
+any sum, however small, would be sufficient as earnest, being given as a
+token that the contract is binding and should be expressly stated so by
+the giver. The giving of earnest, or _hand-money_, as it is sometimes
+called, has now fallen into very general disuse.
+
+
+
+
+EAR-RING, an ornament worn pendent from the ear, and generally suspended
+(especially among the more civilized races) by means of a ring or hook
+passing through the pendulous lobe of the ear. Among savage races the
+impulse to decorate, or at any rate to modify the appearance of the ear,
+is almost universal. With such peoples the ear appendage is chiefly
+remarkable for its extravagant dimensions. Many examples may be seen in
+the ethnographic galleries of the British Museum. The Berawan people of
+Borneo use plugs through the lobe of the ear 33/4 in. in diameter. More
+extraordinary still is an example of a stone ear-plug worn by a Masai,
+41/2 in. in diameter and weighing 2 lb. 14 oz. (_Man_, 1905, p. 22). It is
+stated that according to the Masai standard of fashion, the lobes of the
+ears should be enlarged so as to be capable of meeting above the head.
+Among the superior races, though ear ornaments of extravagant size and
+elaboration are not unknown, moderation in size is commonly observed,
+and greater attention is paid to workmanship and fineness of material.
+
+The general usage appears to have been to have ear-rings worn in pairs,
+the two ornaments in all respects resembling each other; in ancient
+times, or more recently among Oriental races, a single ear-ring has
+sometimes been worn. The use of this kind of ornament, which constantly
+was of great value, dates from the remotest historical antiquity, the
+earliest mention of ear-rings occurring in the book of Genesis. It
+appears probable that the ear-rings of Jacob's family, which he buried
+with his strange idols at Bethel, were regarded as amulets or talismans,
+such unquestionably being the estimation in which some ornaments of this
+class have been held from a very early period, as they still are held in
+the East. Thus in New Zealand ear-rings are decorated with the teeth of
+enemies, and with talismanic sharks' teeth. Among all the Oriental races
+of whom we have any accurate knowledge, the Hebrews and Egyptians
+excepted, ear-rings always have been in general use by both sexes; while
+in the West, as well as by the Hebrews and Egyptians, as a general rule
+they have been considered exclusively female ornaments. By the Greeks
+and Romans also ear-rings were worn only by women, and the wearing of
+them by a man is often spoken of as distinctively oriental.
+
+[Illustration: From _La Grande Encyclopedie_.
+
+FIG. 1.--Ear-ring from an Assyrian bas relief.]
+
+In archaic art, ear-rings are frequently represented or their traces are
+left in the perforated ear lobes of early statues. After the 4th century
+such perforations occur seldom. In one instance, a Greek inscription
+records the weight of the detachable gold ornaments on a statue, among
+which a pair of ear-rings is included. Ear-rings of characteristic form
+are frequently discovered by excavation. In Egypt, a system of pendent
+chains is found hanging from a disk. In Assyria the decoration consists
+of pendants or knobs attached to a rigid ring. In the early civilization
+represented by Dr Schliemann's Trojan investigations, pieces of gold
+plate are suspended by parallel chains. In the Mycenaean period,
+ear-rings are infrequent in Greece, but have been found in abundance in
+the Mycenaean finds of Enkomi (Cyprus) in the form of pendent
+bulls'-heads, or of decorative forms based on the bull's head. In the
+tombs of the Greek settlers in the Crimea (4th century B.C.), ear-rings
+are found of marvellous complexity and beauty. The lexicographer Pollux,
+speaking of the names given to ear-rings, derived from their forms,
+mentions caryatids, hippocamps and centauresses. Jewels of the same
+class, of exquisite beauty and of workmanship that is truly wonderful,
+have been rescued from the sepulchres of ancient Etruria. Ear-rings of
+comparatively simple forms, but set with pearls and other stones, were
+the mode in Rome. In some instances, the stones were of fabulous value.
+During the Byzantine period they once more attained an extravagant size.
+Researches among the burial places of Anglo-Saxon Britain have led to
+the discovery of jewels in considerable numbers, which among their
+varieties include ear-rings executed in a style that proves the
+Anglo-Saxons to have made no inconsiderable advances in the arts of
+civilization.
+
+[Illustration: From _La Grande Encyclopedie_.
+
+FIG. 2.--Thetis crossing the sea, with the armour of Achilles. Ear-ring
+from the Crimea, Hermitage museum.]
+
+These same ornaments, which never have fallen into disuse, enjoy at the
+present day a considerable degree of favour, and the tide of fashion has
+set towards their increased use. Like all other modern jewels, however,
+the ear-rings of our own times as works of art can claim no historical
+attributes, because they consist as well of reproductions from all past
+ages and of every race as of fanciful productions that certainly can be
+assigned to no style of art whatever. As one of the curiosities of the
+subject it may be mentioned that Antonia, wife of Drusus, is said by
+Pliny to have attached a pair of ear-rings to her pet lamprey.
+
+
+
+
+EARTH (a word common to Teutonic languages, cf. Ger. _Erde_, Dutch
+_aarde_, Swed. and Dan. _jord_; outside Teutonic it appears only in the
+Gr. [Greek: eraze], on the ground; it has been connected by some
+etymologists with the Aryan root _ar-_, to plough, which is seen in the
+Lat. _arare_, obsolete Eng. "ear," and Gr. [Greek: aroun], but this is
+now considered very doubtful; see G. Curtius, _Greek Etymology_, Eng.
+trans., i. 426; Max Mueller, _Lectures_, 8th ed. i. 294). From early
+times the word "earth" has been used in several connexions--from that of
+soil or ground to that of the planet which we inhabit, but it is
+difficult to trace the exact historic sequence of the diverse usages. In
+the cosmogony of the Pythagoreans, Platonists and other philosophers,
+the term or its equivalent denoted an element or fundamental quality
+which conferred upon matter the character of earthiness; and in the
+subsequent development of theories as to the ultimate composition of
+matter by the alchemists, iatrochemists, and early phlogistonists an
+element of the same name was retained (see ELEMENT). In modern
+chemistry, the common term "earth" is applied to certain oxides:--the
+"alkaline earths" (q.v.) are the oxides of calcium (lime), barium
+(baryta) and strontium (strontia); the "rare earths" (q.v.) are the
+oxides of a certain class of rare metals.
+
+
+THE EARTH
+
+The terrestrial globe is a member of the Solar system, the third in
+distance from the Sun, and the largest within the orbit of Jupiter. In
+the wider sense it may be regarded as composed of a gaseous atmosphere
+(see METEOROLOGY), which encircles the crust or lithosphere (see
+GEOGRAPHY), and surface waters or hydrosphere (see OCEAN AND
+OCEANOGRAPHY). The description of the surface features is a branch of
+Geography, and the discussions as to their origin and permanence belongs
+to Physiography (in the narrower sense), physiographical geology, or
+physical geography. The investigation of the crust belongs to geology
+and of rocks in particular to petrology.
+
+In the present article we shall treat the subject matter of the Earth as
+a planet under the following headings:--(1) Figure and Size, (2) Mass
+and Density, (3) Astronomical Relations, (4) Evolution and Age. These
+subjects will be treated summarily, readers being referred to the
+article ASTRONOMY and to the cross-references for details.
+
+1. _Figure and Size._--To primitive man the Earth was a flat disk with
+its surface diversified by mountains, rivers and seas. In many
+cosmogonies this disk was encircled by waters, unmeasurable by man and
+extending to a junction with the sky; and the disk stood as an island
+rising up through the waters from the floor of the universe, or was
+borne as an immovable ship on the surface. Of such a nature was the
+cosmogony of the Babylonians and Hebrews; Homer states the same idea,
+naming the encircling waters [Greek: Okeanos]; and Hesiod regarded it as
+a disk midway between the sky and the infernal regions. The theory that
+the Earth extended downwards to the limit of the universe was subjected
+to modification when it was seen that the same sun and stars reappeared
+in the east after their setting in the west. But man slowly realized
+that the earth was isolated in space, floating freely as a balloon, and
+much speculation was associated about that which supported the Earth.
+Tunnels in the foundations to permit the passage of the sun and stars
+were suggested; the Greeks considered twelve columns to support the
+heavens, and in their mythology the god Atlas appears condemned to
+support the columns; while the Egyptians had the Earth supported by four
+elephants, which themselves stood on a tortoise swimming on a sea.
+Earthquakes were regarded as due to a movement of these foundations; in
+Japan this was considered to be due to the motion of a great spider, an
+animal subsequently replaced by a cat-fish; in Mongolia it is a hog; in
+India, a mole; in some parts of South America, a whale; and among some
+of the North American Indians, a giant tortoise.
+
+The doctrine of the spherical form has been erroneously assigned to
+Thales; but he accepted the Semitic conception of the disk, and regarded
+the production of springs after earthquakes as due to the inrushing of
+the waters under the Earth into fissures in the surface. His pupil,
+Anaximander (610-547), according to Diogenes Laertius, believed it to be
+spherical (see _The Observatory_, 1894, P. 208); and Anaximenes probably
+held a similar view. The spherical form is undoubtedly a discovery of
+Pythagoras, and was taught by the Pythagoreans and by the Eleatic
+Parmenides. The expositor of greatest moment was Aristotle; his
+arguments are those which we employ to-day:--the ship gradually
+disappearing from hull to mast as it recedes from the harbour to the
+horizon; the circular shadow cast by the Earth on the Moon during an
+eclipse, and the alteration in the appearance of the heavens as one
+passes from point to point on the Earth's surface.[1] He records
+attempts made to determine the circumference; but the first scientific
+investigation in this direction was made 150 years later by
+Eratosthenes. The spherical form, however, only became generally
+accepted after the Earth's circumnavigation (see GEOGRAPHY).
+
+The historical development of the methods for determining the figure of
+the Earth (by which we mean a theoretical surface in part indicated by
+the ocean at rest, and in other parts by the level to which water freely
+communicating with the oceans by canals traversing the land masses would
+rise) and the mathematical investigation of this problem are treated in
+the articles EARTH, FIGURE OF THE, and GEODESY; here the results are
+summarized. Sir Isaac Newton deduced from the mechanical consideration
+of the figure of equilibrium of a mass of rotating fluid, the form of an
+oblate spheroid, the ellipticity of a meridian section being {1/231},
+and the axes in the ratio 230 : 231. Geodetic measurements by the
+Cassinis and other French astronomers pointed to a prolate form, but the
+Newtonian figure was proved to be correct by the measurement of
+meridional arcs in Peru and Lapland by the expeditions organized by the
+French Academy of Sciences. More recent work points to an elliptical
+equatorial section, thus making the earth pear-shaped. The position of
+the longer axis is somewhat uncertain; it is certainly in Africa, Clarke
+placing it in longitude 8 deg. 15' W., and Schubert in longitude 41 deg. 4' E.;
+W.J. Sollas, arguing from terrestrial symmetry, has chosen the position
+lat. 6 deg. N., long. 28 deg. E., i.e. between Clarke's and Schubert's
+positions. For the lengths of the axes and the ellipticity of the Earth,
+see EARTH, FIGURE OF THE.
+
+2. _Mass and Density._--The earliest scientific investigation on the
+density and mass of the Earth (the problem is really single if the
+volume of the Earth be known) was made by Newton, who, mainly from
+astronomical considerations, suggested the limiting densities 5 and 6;
+it is remarkable that this prophetic guess should be realized, the mean
+value from subsequent researches being about 51/2, which gives for the
+mass the value 6 x 10^21 tons. The density of the Earth has been
+determined by several experimenters within recent years by methods
+described in the article GRAVITATION; the most probable value is there
+stated to be 5.527.
+
+3. _Astronomical Relations._--The grandest achievements of astronomical
+science are undoubtedly to be associated with the elucidation of the
+complex motion of our planet. The notion that the Earth was fixed and
+immovable at the centre of an immeasurable universe long possessed the
+minds of men; and we find the illustrious Ptolemy accepting this view in
+the 2nd century A.D., and rejecting the notion of a rotating Earth--a
+theory which had been proposed as early as the 5th century B.C. by
+Philolaus on philosophical grounds, and in the 3rd century B.C. by the
+astronomer Aristarchus of Samos. He argued that if the Earth rotated
+then points at the equator had the enormous velocity of about 1000 m.
+per hour, and as a consequence there should be terrific gales from the
+east; the fact that there were no such gales invalidated, in his
+opinion, the theory. The Ptolemaic theory was unchallenged until 1543,
+in which year the _De Revolutionibus orbium Celestium_ of Copernicus was
+published. In this work it was shown that the common astronomical
+phenomena could be more simply explained by regarding the Earth as
+annually revolving about a fixed Sun, and daily rotating about itself. A
+clean sweep was made of the geocentric epicyclic motions of the planets
+which Ptolemy's theory demanded, and in place there was substituted a
+procession of planets about the Sun at different distances. The
+development of the Copernican theory--the corner-stone of modern
+astronomy--by Johann Kepler and Sir Isaac Newton is treated in the
+article ASTRONOMY: _History_; here we shall summarily discuss the
+motions of our planet and its relation to the solar system.
+
+The Earth has two principal motions--revolution about the Sun, rotation
+about its axis; there are in addition a number of secular motions.
+
+_Revolution._--The Earth revolves about the Sun in an elliptical orbit
+having the Sun at one focus. The plane of the orbit is termed the
+ecliptic; it is inclined to the Earth's equator at an angle termed the
+obliquity, and the points of intersection of the equator and ecliptic
+are termed the equinoctial points. The major axis of the ellipse is the
+line of apsides; when the Earth is nearest the Sun it is said to be in
+perihelion, when farthest it is in aphelion. The mean distance of the
+Earth from the Sun is a most important astronomical constant, since it
+is the unit of linear measurement; its value is about 93,000,000 m., and
+the difference between the perihelion and aphelion distances is about
+3,000,000 m. The eccentricity of the orbit is 0.016751. A tabular
+comparison of the orbital constants of the Earth and the other planets
+is given in the article PLANET. The period of revolution with regard to
+the Sun, or, in other words, the time taken by the Sun apparently to
+pass from one equinox to the same equinox, is the tropical or
+equinoctial year; its length is 365 d. 5 hrs. 48 m. 46 secs. It is about
+20 minutes shorter than the true or sidereal year, which is the time
+taken for the Sun apparently to travel from one star to it again. The
+difference in these two years is due to the secular variation termed
+precession (see below). A third year is named the _anomalistic year_,
+which is the time occupied in the passage from perihelion to perihelion;
+it is a little longer than the sidereal.
+
+_Rotation._--The Earth rotates about an axis terminating at the north
+and south geographical poles, and perpendicular to the equator; the
+period of rotation is termed the day (q.v.), of which several kinds are
+distinguished according to the body or point of reference. The rotation
+is performed from west to east; this daily rotation occasions the
+_diurnal_ motion of the celestial sphere, the rising of the Sun and
+stars in the east and their setting in the west, and also the phenomena
+of day and night. The inclination of the axis to the ecliptic brings
+about the presentation of places in different latitudes to the more
+direct rays of the sun; this is revealed in the variation in the length
+of daylight with the time of the year, and the phenomena of seasons.
+
+Although the rotation of the Earth was an accepted fact soon after its
+suggestion by Copernicus, an experimental proof was wanting until 1851,
+when Foucault performed his celebrated pendulum experiment at the
+Pantheon, Paris. A pendulum about 200 ft. long, composed of a flexible
+wire carrying a heavy iron bob, was suspended so as to be free to
+oscillate in any direction. The bob was provided with a style which
+passed over a table strewn with fine sand, so that the style traced the
+direction in which the bob was swinging. It was found that the
+oscillating pendulum never retraced its path, but at each swing it was
+apparently deviated to the right, and moreover the deviations in equal
+times were themselves equal. This means that the floor of the Pantheon
+was moving, and therefore the Earth was rotating. If the pendulum were
+swung in the southern hemisphere, the deviation would be to the left; if
+at the equator it would not deviate, while at the poles the plane of
+oscillation would traverse a complete circle in 24 hours.
+
+The rotation of the Earth appears to be perfectly uniform, comparisons
+of the times of transits, eclipses, &c., point to a variation of less
+than {1/100}th of a second since the time of Ptolemy. Theoretical
+investigations on the phenomena of tidal friction point, however, to a
+retardation, which may to some extent be diminished by the accelerations
+occasioned by the shrinkage of the globe, and some other factors
+difficult to evaluate (see TIDE).
+
+We now proceed to the secular variations.
+
+_Precession._--The axis of the earth does not preserve an invariable
+direction in space, but in a certain time it describes a cone, in much
+the same manner as the axis of a top spinning out of the vertical. The
+equator, which preserves approximately the same inclination to the
+ecliptic (there is a slight variation in the obliquity which we shall
+mention later), must move so that its intersections with the ecliptic,
+or equinoctial points, pass in a retrograde direction, i.e. opposite to
+that of the Earth. This motion is termed the precession of the
+equinoxes, and was observed by Hipparchus in the 2nd century B.C.;
+Ptolemy corrected the catalogue of Hipparchus for precession by adding
+2 deg. 40' to the longitudes, the latitudes being unaltered by this motion,
+which at the present time is 50.26" annually, the complete circuit being
+made in about 26,000 years. Owing to precession the signs of the zodiac
+are traversing paths through the constellations, or, in other
+words, the constellations are continually shifting with regard to the
+equinoctial points; at one time the vernal equinox Aries was in the
+constellations of that name; it is now in Pisces, and will then pass
+into Aquarius. The pole star, i.e. the star towards which the Earth's
+axis points, is also shifting owing to precession; in about 2700 B.C.
+the Chinese observed [alpha] Draconis as the pole star (at present
+[alpha] Ursae minoris occupies this position and will do so until 3500);
+in 13600 Vega ([alpha] Lyrae) the brightest star in the Northern
+hemisphere, will be nearest.
+
+Precession is the result of the Sun and the Moon's attraction on the
+Earth not being a single force through its centre of gravity. If the
+Earth were a homogeneous sphere the attractions would act through the
+centre, and such forces would have no effect upon the rotation about the
+centre of gravity, but the Earth being spheroidal the equatorial band
+which stands up as it were beyond the surface of a sphere is more
+strongly attracted, with the result that the axis undergoes a tilting.
+The precession due to the Sun is termed the _solar precession_ and that
+due to the Moon the _lunar precession_; the joint effect (two-thirds of
+which is due to the Moon) is the _luni-solar_ precession. Solar
+precession is greatest at the solstices and zero at the equinoxes; the
+part of luni-solar precession due to the Moon varies with the position
+of the Moon in its orbit. The obliquity is unchanged by precession (see
+PRECESSION OF THE EQUINOXES).
+
+_Nutation._--In treating precession we have stated that the axis of the
+Earth traces a cone, and it follows that the pole describes a circle
+(approximately) on the celestial sphere, about the pole of the ecliptic.
+This is not quite true. Irregularities in the attracting forces which
+occasion precession also cause a slight oscillation backwards and
+forwards over the mean precessional path of the pole, the pole tracing a
+wavy line or nodding. Both the Sun and Moon contribute to this effect.
+Solar nutation depends upon the position of the Sun on the ecliptic; its
+period is therefore 1 year, and in extent it is only 1.2"; lunar
+nutation depends upon the position of the Moon's nodes; its period is
+therefore about 18.6 years, the time of revolution of the nodes, and its
+extent is 9.2". There is also given to the obliquity a small oscillation
+to and fro. Nutation is one of the great discoveries of James Bradley
+(1747).
+
+_Planetary Precession._--So far we have regarded the ecliptic as
+absolutely fixed, and treated precession as a real motion of the
+equator. The ecliptic (q.v.), however, is itself subject to a motion,
+due to the attractions of the planets on the Earth. This effect also
+displaces the equinoctial points. Its annual value is 0.13". The term
+General Precession in longitude is given to the displacement of the
+intersection of the equator with the apparent ecliptic on the latter.
+The standard value is 50.2453", which prevailed in 1850, and the value
+at 1850 + t, i.e. the constant of precession, is 50.2453" + 0.0002225"
+t. This value is also liable to a very small change. The nutation of the
+obliquity at time 1850 + t is given by the formula 23 deg. 27' 32.0" - 0.47"
+t. Complete expressions for these functions are given in Newcomb's
+_Spherical Astronomy_ (1908), and in the _Nautical Almanac_.
+
+The variation of the _line of apsides_ is the name given to the motion
+of the major axis of the Earth's orbit along the ecliptic. It is due to
+the general influence of the planets, and the revolution is effected in
+21,000 years.
+
+The variation of the eccentricity denotes an oscillation of the form of
+the Earth's orbit between a circle and ellipse. This followed the
+mathematical researches of Lagrange and Leverrier. It was suggested by
+Sir John Herschel in 1830 that this variation might occasion great
+climatic changes, and James Croll developed the theory as affording a
+solution of the glacial periods in geology (q.v.).
+
+_Variation of Latitude._--Another secular motion of the Earth is due to
+the fact that the axis of rotation is not rigidly fixed within it, but
+its polar extremities wander in a circle of about 50 ft. diameter. This
+oscillation brings about a variability in terrestrial latitudes, hence
+the name. Euler showed mathematically that such an oscillation existed,
+and, making certain assumptions as to the rigidity of the Earth, deduced
+that its period was 305 days; S.C. Chandler, from 1890 onwards, deduced
+from observations of the stars a period of 428 days; and Simon Newcomb
+explained the deviation of these periods by pointing out that Euler's
+assumption of a perfectly rigid Earth is not in accordance with fact.
+For details of this intricate subject see the articles LATITUDE and
+EARTH, FIGURE OF THE.
+
+4. _Evolution and Age._--In its earliest history the mass now
+consolidated as the Earth and Moon was part of a vast nebulous
+aggregate, which in the course of time formed a central nucleus--our
+Sun--which shed its outer layers in such a manner as to form the solar
+system (see NEBULAR THEORY). The moon may have been formed from the
+Earth in a similar manner, but the theory of tidal friction suggests the
+elongation of the Earth along an equatorial axis to form a pear-shaped
+figure, and that in the course of time the protuberance shot off to form
+the Moon (see TIDE). The age of the Earth has been investigated from
+several directions, as have also associated questions related to
+climatic changes, internal temperature, orientation of the land and
+water (permanence of oceans and continents), &c. These problems are
+treated in the articles GEOLOGY and GEOGRAPHY.
+
+
+FOOTNOTE:
+
+  [1] Aristotle regarded the Earth as having an upper inhabited half
+    and a lower uninhabited one, and the air on the lower half as tending
+    to flow upwards through the Earth. The obstruction of this passage
+    brought about an accumulation of air within the Earth, and the
+    increased pressure may occasion oscillations of the surface, which
+    may be so intense as to cause earthquakes.
+
+
+
+
+EARTH, FIGURE OF THE. The determination of the figure of the earth is a
+problem of the highest importance in astronomy, inasmuch as the diameter
+of the earth is the unit to which all celestial distances must be
+referred.
+
+
+_Historical._
+
+Reasoning from the uniform level appearance of the horizon, the
+variations in altitude of the circumpolar stars as one travels towards
+the north or south, the disappearance of a ship standing out to sea, and
+perhaps other phenomena, the earliest astronomers regarded the earth as
+a sphere, and they endeavoured to ascertain its dimensions. Aristotle
+relates that the mathematicians had found the circumference to be
+400,000 stadia (about 46,000 miles). But Eratosthenes (c. 250 B.C.)
+appears to have been the first who entertained an accurate idea of the
+principles on which the determination of the figure of the earth really
+depends, and attempted to reduce them to practice. His results were very
+inaccurate, but his method is the same as that which is followed at the
+present day--depending, in fact, on the comparison of a line measured on
+the earth's surface with the corresponding arc of the heavens. He
+observed that at Syene in Upper Egypt, on the day of the summer
+solstice, the sun was exactly vertical, whilst at Alexandria at the same
+season of the year its zenith distance was 7 deg. 12', or one-fiftieth of
+the circumference of a circle. He assumed that these places were on the
+same meridian; and, reckoning their distance apart as 5000 stadia, he
+inferred that the circumference of the earth was 250,000 stadia (about
+29,000 miles). A similar attempt was made by Posidonius, who adopted a
+method which differed from that of Eratosthenes only in using a star
+instead of the sun. He obtained 240,000 stadia (about 27,600 miles) for
+the circumference. Ptolemy in his _Geography_ assigns the length of the
+degree as 500 stadia.
+
+The Arabs also investigated the question of the earth's magnitude. The
+caliph Abdallah al Mamun (A.D. 814), having fixed on a spot in the
+plains of Mesopotamia, despatched one company of astronomers northwards
+and another southwards, measuring the journey by rods, until each found
+the altitude of the pole to have changed one degree. But the result of
+this measurement does not appear to have been very satisfactory. From
+this time the subject seems to have attracted no attention until about
+1500, when Jean Fernel (1497-1558), a Frenchman, measured a distance in
+the direction of the meridian near Paris by counting the number of
+revolutions of the wheel of a carriage. His astronomical observations
+were made with a triangle used as a quadrant, and his resulting length
+of a degree was very near the truth.
+
+Willebrord Snell[1] substituted a chain of triangles for actual linear
+measurement. He measured his base line on the frozen surface of the
+meadows near Leiden, and measured the angles of his triangles, which lay
+between Alkmaar and Bergen-op-Zoom, with a quadrant and semicircles. He
+took the precaution of comparing his standard with that of the French,
+so that his result was expressed in toises (the length of the toise is
+about 6.39 English ft.). The work was recomputed and reobserved by P.
+von Musschenbroek in 1729. In 1637 an Englishman, Richard Norwood,
+published a determination of the figure of the earth in a volume
+entitled _The Seaman's Practice, contayning a Fundamentall Probleme in
+Navigation experimentally verified, namely, touching the Compasse of the
+Earth and Sea and the quantity of a Degree in our English Measures_. He
+observed on the 11th of June 1633 the sun's meridian altitude in London
+as 62 deg. 1', and on the 6th of June 1635, his meridian altitude in York as
+59 deg. 33'. He measured the distance between these places partly with a
+chain and partly by pacing. By this means, through compensation of
+errors, he arrived at 367,176 ft. for the degree--a very fair result.
+
+The application of the telescope to angular instruments was the next
+important step. Jean Picard was the first who in 1669, with the
+telescope, using such precautions as the nature of the operation
+requires, measured an arc of meridian. He measured with wooden rods a
+base line of 5663 toises, and a second or base of verification of 3902
+toises; his triangulation extended from Malvoisine, near Paris, to
+Sourdon, near Amiens. The angles of the triangles were measured with a
+quadrant furnished with a telescope having cross-wires. The difference
+of latitude of the terminal stations was determined by observations made
+with a sector on a star in Cassiopeia, giving 1 deg. 22' 55" for the
+amplitude. The terrestrial measurement gave 78,850 toises, whence he
+inferred for the length of the degree 57,060 toises.
+
+Hitherto geodetic observations had been confined to the determination of
+the magnitude of the earth considered as a sphere, but a discovery made
+by Jean Richer (d. 1696) turned the attention of mathematicians to its
+deviation from a spherical form. This astronomer, having been sent by
+the Academy of Sciences of Paris to the island of Cayenne, in South
+America, for the purpose of investigating the amount of astronomical
+refraction and other astronomical objects, observed that his clock,
+which had been regulated at Paris to beat seconds, lost about two
+minutes and a half daily at Cayenne, and that in order to bring it to
+measure mean solar time it was necessary to shorten the pendulum by more
+than a line (about {1/12}th of an in.). This fact, which was scarcely
+credited till it had been confirmed by the subsequent observations of
+Varin and Deshayes on the coasts of Africa and America, was first
+explained in the third book of Newton's _Principia_, who showed that it
+could only be referred to a diminution of gravity arising either from a
+protuberance of the equatorial parts of the earth and consequent
+increase of the distance from the centre, or from the counteracting
+effect of the centrifugal force. About the same time (1673) appeared
+Christian Huygens' _De Horologio Oscillatorio_, in which for the first
+time were found correct notions on the subject of centrifugal force. It
+does not, however, appear that they were applied to the theoretical
+investigation of the figure of the earth before the publication of
+Newton's _Principia_. In 1690 Huygens published his _De Causa
+Gravitatis_, which contains an investigation of the figure of the earth
+on the supposition that the attraction of every particle is towards the
+centre.
+
+Between 1684 and 1718 J. and D. Cassini, starting from Picard's base,
+carried a triangulation northwards from Paris to Dunkirk and southwards
+from Paris to Collioure. They measured a base of 7246 toises near
+Perpignan, and a somewhat shorter base near Dunkirk; and from the
+northern portion of the arc, which had an amplitude of 2 deg. 12' 9",
+obtained for the length of a degree 56,960 toises; while from the
+southern portion, of which the amplitude was 6 deg. 18' 57", they obtained
+57,097 toises. The immediate inference from this was that, the degree
+diminishing with increasing latitude, the earth must be a prolate
+spheroid. This conclusion was totally opposed to the theoretical
+investigations of Newton and Huygens, and accordingly the Academy of
+Sciences of Paris determined to apply a decisive test by the measurement
+of arcs at a great distance from each other--one in the neighbourhood of
+the equator, the other in a high latitude. Thus arose the celebrated
+expeditions of the French academicians. In May 1735 Louis Godin, Pierre
+Bouguer and Charles Marie de la Condamine, under the auspices of Louis
+XV., proceeded to Peru, where, assisted by two Spanish officers, after
+ten years of laborious exertion, they measured an arc of 3 deg. 7', the
+northern end near the equator. The second party consisted of Pierre
+Louis Moreau de Maupertuis, Alexis Claude Clairault, Charles Etienne
+Louis Camus, Pierre Charles Lemonnier, and Reginaud Outhier, who reached
+the Gulf of Bothnia in July 1736; they were in some respects more
+fortunate than the first party, inasmuch as they completed the
+measurement of an arc near the polar circle of 57' amplitude and
+returned within sixteen months from the date of their departure.
+
+The measurement of Bouguer and De la Condamine was executed with great
+care, and on account of the locality, as well as the manner in which all
+the details were conducted, it has always been regarded as a most
+valuable determination. The southern limit was at Tarqui, the northern
+at Cotchesqui. A base of 6272 toises was measured in the vicinity of
+Quito, near the northern extremity of the arc, and a second base of 5260
+toises near the southern extremity. The mountainous nature of the
+country made the work very laborious, in some cases the difference of
+heights of two neighbouring stations exceeding 1 mile; and they had much
+trouble with their instruments, those with which they were to determine
+the latitudes proving untrustworthy. But they succeeded by simultaneous
+observations of the same star at the two extremities of the arc in
+obtaining very fair results. The whole length of the arc amounted to
+176,945 toises, while the difference of latitudes was 3 deg. 7' 3". In
+consequence of a misunderstanding that arose between De la Condamine and
+Bouguer, their operations were conducted separately, and each wrote a
+full account of the expedition. Bouguer's book was published in 1749;
+that of De la Condamine in 1751. The toise used in this measure was
+afterwards regarded as the standard toise, and is always referred to as
+the _Toise of Peru_.
+
+The party of Maupertuis, though their work was quickly despatched, had
+also to contend with great difficulties. Not being able to make use of
+the small islands in the Gulf of Bothnia for the trigonometrical
+stations, they were forced to penetrate into the forests of Lapland,
+commencing operations at Tornea, a city situated on the mainland near
+the extremity of the gulf. From this, the southern extremity of their
+arc, they carried a chain of triangles northward to the mountain Kittis,
+which they selected as the northern terminus. The latitudes were
+determined by observations with a sector (made by George Graham) of the
+zenith distance of [alpha] and [delta] Draconis. The base line was
+measured on the frozen surface of the river Tornea about the middle of
+the arc; two parties measured it separately, and they differed by about
+4 in. The result of the whole was that the difference of latitudes of
+the terminal stations was 57' 29" .6, and the length of the arc 55,023
+toises. In this expedition, as well as in that to Peru, observations
+were made with a pendulum to determine the force of gravity; and these
+observations coincided with the geodetic results in proving that the
+earth was an oblate and not prolate spheroid.
+
+In 1740 was published in the Paris _Memoires_ an account, by Cassini de
+Thury, of a remeasurement by himself and Nicolas Louis de Lacaille of
+the meridian of Paris. With a view to determine more accurately the
+variation of the degree along the meridian, they divided the distance
+from Dunkirk to Collioure into four partial arcs of about two degrees
+each, by observing the latitude at five stations. The results previously
+obtained by J. and D. Cassini were not confirmed, but, on the contrary,
+the length of the degree derived from these partial arcs showed on the
+whole an increase with an increasing latitude. Cassini and Lacaille also
+measured an arc of parallel across the mouth of the Rhone. The
+difference of time of the extremities was determined by the observers at
+either end noting the instant of a signal given by flashing gunpowder at
+a point near the middle of the arc.
+
+While at the Cape of Good Hope in 1752, engaged in various astronomical
+observations, Lacaille measured an arc of meridian of 1 deg. 13' 17", which
+gave him for the length of the degree 57,037 toises--an unexpected
+result, which has led to the remeasurement of the arc by Sir Thomas
+Maclear (see GEODESY).
+
+Passing over the measurements made between Rome and Rimini and on the
+plains of Piedmont by the Jesuits Ruggiero Giuseppe Boscovich and
+Giovanni Battista Beccaria, and also the arc measured with deal rods in
+North America by Charles Mason and Jeremiah Dixon, we come to the
+commencement of the English triangulation. In 1783, in consequence of a
+representation from Cassini de Thury on the advantages that would accrue
+from the geodetic connexion of Paris and Greenwich, General William Roy
+was, with the king's approval, appointed by the Royal Society to conduct
+the operations on the part of England, Count Cassini, Mechain and
+Delambre being appointed on the French side. A precision previously
+unknown was attained by the use of Ramsden's theodolite, which was the
+first to make the spherical excess of triangles measurable. The wooden
+rods with which the first base was measured were replaced by glass rods,
+which were afterwards rejected for the steel chain of Ramsden. (For
+further details see _Account of the Trigonometrical Survey of England
+and Wales_.)
+
+Shortly after this, the National Convention of France, having agreed to
+remodel their system of weights and measures, chose for their unit of
+length the ten-millionth part of the meridian quadrant. In order to
+obtain this length precisely, the remeasurement of the French meridian
+was resolved on, and deputed to J.B.J. Delambre and Pierre Francois
+Andre Mechain. The details of this operation will be found in the _Base
+du systeme metrique decimale_. The arc was subsequently extended by Jean
+Baptiste Biot and Dominique Francois Jean Arago to the island of Iviza.
+Operations for the connexion of England with the continent of Europe
+were resumed in 1821 to 1823 by Henry Kater and Thomas Frederick Colby
+on the English side, and F.J.D. Arago and Claude Louis Mathieu on the
+French.
+
+The publication in 1838 of Friedrich Wilhelm Bessel's _Gradmessung in
+Ostpreussen_ marks an era in the science of geodesy. Here we find the
+method of least squares applied to the calculation of a network of
+triangles and the reduction of the observations generally. The
+systematic manner in which all the observations were taken with the view
+of securing final results of extreme accuracy is admirable. The
+triangulation, which was a small one, extended about a degree and a half
+along the shores of the Baltic in a N.N.E. direction. The angles were
+observed with theodolites of 12 and 15 in. diameter, and the latitudes
+determined by means of the transit instrument in the prime vertical--a
+method much used in Germany. (The base apparatus is described in the
+article GEODESY.)
+
+The principal triangulation of Great Britain and Ireland, which was
+commenced in 1783 under General Roy, for the more immediate purpose of
+connecting the observatories of Greenwich and Paris, had been gradually
+extended, under the successive direction of Colonel E. Williams, General
+W. Mudge, General T.F. Colby, Colonel L.A. Hall, and Colonel Sir Henry
+James; it was finished in 1851. The number of stations is about 250. At
+32 of these the latitudes were determined with Ramsden's and Airy's
+zenith sectors. The theodolites used for this work were, in addition to
+the two great theodolites of Ramsden which were used by General Roy and
+Captain Kater, a smaller theodolite of 18 in. diameter by the same
+mechanician, and another of 24 in. diameter by Messrs Troughton and
+Simms. Observations for determination of absolute azimuth were made with
+those instruments at a large number of stations; the stars [alpha],
+[delta], and [lambda] Ursae Minoris and 51 Cephei being those observed
+always at the greatest azimuths. At six of these stations the probable
+error of the result is under 0.4", at twelve under 0.5", at thirty-four
+under 0.7": so that the absolute azimuth of the whole network is
+determined with extreme accuracy. Of the seven base lines which have
+been measured, five were by means of steel chains and two with Colby's
+compensation bars (see GEODESY). The triangulation was computed by least
+squares. The total number of equations of condition for the
+triangulation is 920; if therefore the whole had been reduced in one
+mass, as it should have been, the solution of an equation of 920 unknown
+quantities would have occurred as a part of the work. To avoid this an
+approximation was resorted to; the triangulation was divided into
+twenty-one parts or figures; four of these, not adjacent, were first
+adjusted by the method explained, and the corrections thus determined in
+these figures carried into the equations of condition of the adjacent
+figures. The average number of equations in a figure is 44; the largest
+equation is one of 77 unknown quantities. The vertical limb of Airy's
+zenith sector is read by four microscopes, and in the complete
+observation of a star there are 10 micrometer readings and 12 level
+readings. The instrument is portable; and a complete determination of
+latitude, affected with the mean of the declination errors of two stars,
+is effected by two micrometer readings and four level readings. The
+observation consists in measuring with the telescope micrometer the
+difference of zenith distances of two stars which cross the meridian,
+one to the north and the other to the south of the observer at zenith
+distances which differ by not much more than 10' or 15', the interval of
+the times of transit being not less than one nor more than twenty
+minutes. The advantages are that, with simplicity in the construction of
+the instrument and facility in the manipulation, refraction is
+eliminated (or nearly so, as the stars are generally selected within 25 deg.
+of the zenith), and there is no large divided circle. The telescope,
+which is counterpoised on one side of the vertical axis, has a small
+circle for finding, and there is also a small horizontal circle. This
+instrument is universally used in American geodesy.
+
+  The principal work containing the methods and results of these
+  operations was published in 1858 with the title "Ordnance
+  Trigonometrical Survey of Great Britain and Ireland. Account of the
+  observations and calculations of the principal triangulation and of
+  the figure, dimensions and mean specific gravity of the earth as
+  derived therefrom. Drawn up by Captain Alexander Ross Clarke, R.E.,
+  F.R.A.S., under the direction of Lieut.-Colonel H. James, R.E.,
+  F.R.S., M.R.I.A., &c." A supplement appeared in 1862: "Extension of
+  the Triangulation of the Ordnance Survey into France and Belgium, with
+  the measurement of an arc of parallel in 52 deg. N. from Valentia in
+  Ireland to Mount Kemmel in Belgium. Published by ... Col. Sir Henry
+  James."
+
+Extensive operations for surveying India and determining the figure of
+the earth were commenced in 1800. Colonel W. Lambton started the great
+meridian arc at Punnae in latitude 8 deg. 9', and, following generally the
+methods of the English survey, he carried his triangulation as far north
+as 20 deg. 30'. The work was continued by Sir George (then Captain) Everest,
+who carried it to the latitude of 29 deg. 30'. Two admirable volumes by Sir
+George Everest, published in 1830 and in 1847, give the details of this
+undertaking. The survey was afterwards prosecuted by Colonel T.T.
+Walker, R.E., who made valuable contributions to geodesy. The working
+out of the Indian chains of triangle by the method of least squares
+presents peculiar difficulties, but, enormous in extent as the work was,
+it has been thoroughly carried out. The ten base lines on which the
+survey depends were measured with Colby's compensation bars.
+
+  The survey is detailed in eighteen volumes, published at Dehra Dun,
+  and entitled _Account of the Operations of the Great Trigonometrical
+  Survey of India_. Of these the first nine were published under the
+  direction of Colonel Walker; and the remainder by Colonels Strahan and
+  St G.C. Gore, Major S.G. Burrard and others. Vol. i., 1870, treats of
+  the base lines; vol. ii., 1879, history and general descriptions of
+  the principal triangulation and of its reduction; vol. v., 1879,
+  pendulum operations (Captains T.P. Basevi and W.T. Heaviside); vols.
+  xi., 1890, and xviii., 1906, latitudes; vols. ix., 1883, x., 1887,
+  xv., 1893, longitudes; vol. xvii., 1901, the Indo-European
+  longitude-arcs from Karachi to Greenwich. The other volumes contain
+  the triangulations.
+
+In 1860 Friedrich Georg Wilhelm Struve published his _Arc du meridien de
+25 deg. 20' entre le Danube et la Mer Glaciale mesure depuis 1816 jusqu'en
+1855_. The latitudes of the thirteen astronomical stations of this arc
+were determined partly with vertical circles and partly by means of the
+transit instrument in the prime vertical. The triangulation, a great
+part of which, however, is a simple chain of triangles, is reduced by
+the method of least squares, and the probable errors of the resulting
+distances of parallels is given; the probable error of the whole arc in
+length is +- 6.2 toises. Ten base lines were measured. The sum of the
+lengths of the ten measured bases is 29,863 toises, so that the average
+length of a base line is 19,100 ft. The azimuths were observed at
+fourteen stations. In high latitudes the determination of the meridian
+is a matter of great difficulty; nevertheless the azimuths at all the
+northern stations were successfully determined,--the probable error of
+the result at Fuglenaes being +- 0".53.
+
+Before proceeding with the modern developments of geodetic measurements
+and their application to the figure of the earth, we must discuss the
+"mechanical theory," which is indispensable for a full understanding of
+the subject.
+
+
+_Mechanical Theory._
+
+Newton, by applying his theory of gravitation, combined with the
+so-called centrifugal force, to the earth, and assuming that an oblate
+ellipsoid of rotation is a form of equilibrium for a homogeneous fluid
+rotating with uniform angular velocity, obtained the ratio of the axes
+229:230, and the law of variation of gravity on the surface. A few years
+later Huygens published an investigation of the figure of the earth,
+supposing the attraction of every particle to be towards the centre of
+the earth, obtaining as a result that the proportion of the axes should
+be 578 : 579. In 1740 Colin Maclaurin, in his _De causa physica fluxus
+et refluxus maris_, demonstrated that the oblate ellipsoid of revolution
+is a figure which satisfies the conditions of equilibrium in the case of
+a revolving homogeneous fluid mass, whose particles attract one another
+according to the law of the inverse square of the distance; he gave the
+equation connecting the ellipticity with the proportion of the
+centrifugal force at the equator to gravity, and determined the
+attraction on a particle situated anywhere on the surface of such a
+body. In 1743 Clairault published his _Theorie de la figure de la
+terre_, which contains a remarkable theorem ("Clairault's Theorem"),
+establishing a relation between the ellipticity of the earth and the
+variation of gravity from the equator to the poles. Assuming that the
+earth is composed of concentric ellipsoidal strata having a common axis
+of rotation, each stratum homogeneous in itself, but the ellipticities
+and densities of the successive strata varying according to any law, and
+that the superficial stratum has the same form as if it were fluid, he
+proved that
+
+  g'- g       5
+  ----- + e = -- m,
+    g         2
+
+where g, g' are the amounts of gravity at the equator and at the pole
+respectively, e the ellipticity of the meridian (or "flattening"), and m
+the ratio of the centrifugal force at the equator to g. He also proved
+that the increase of gravity in proceeding from the equator to the poles
+is as the square of the sine of the latitude. This, taken with the
+former theorem, gives the means of determining the earth's ellipticity
+from observation of the relative force of gravity at any two places.
+P.S. Laplace, who devoted much attention to the subject, remarks on
+Clairault's work that "the importance of all his results and the
+elegance with which they are presented place this work amongst the most
+beautiful of mathematical productions" (Isaac Todhunter's _History of
+the Mathematical Theories of Attraction and the Figure of the Earth_,
+vol. i. p. 229).
+
+The problem of the figure of the earth treated as a question of
+mechanics or hydrostatics is one of great difficulty, and it would be
+quite impracticable but for the circumstance that the surface differs
+but little from a sphere. In order to express the forces at any point of
+the body arising from the attraction of its particles, the form of the
+surface is required, but this form is the very one which it is the
+object of the investigation to discover; hence the complexity of the
+subject, and even with all the present resources of mathematicians only
+a partial and imperfect solution can be obtained.
+
+  We may here briefly indicate the line of reasoning by which some of
+  the most important results may be obtained. If X, Y, Z be the
+  components parallel to three rectangular axes of the forces acting on
+  a particle of a fluid mass at the point x, y, z, then, p being the
+  pressure there, and [rho] the density,
+
+    dp = [rho](Xdx + Ydy + Zdz);
+
+  and for equilibrium the necessary conditions are, that [rho](Xdx + Ydy
+  + Zdz) be a complete differential, and at the free surface Xdx + Ydy +
+  Zdz = 0. This equation implies that the resultant of the forces is
+  normal to the surface at every point, and in a homogeneous fluid it is
+  obviously the differential equation of all surfaces of equal pressure.
+  If the fluid be heterogeneous then it is to be remarked that for
+  forces of attraction according to the ordinary law of gravitation, if
+  X, Y, Z be the components of the attraction of a mass whose potential
+  is V, then
+
+                       dV     dV     dV
+    Xdx + Ydy + Zdz =  --dx + --dy + --dz,
+                       dx     dy     dz
+
+  which is a complete differential. And in the case of a fluid rotating
+  with uniform velocity, in which the so-called centrifugal force enters
+  as a force acting on each particle proportional to its distance from
+  the axis of rotation, the corresponding part of Xdx + Ydy + Zdz is
+  obviously a complete differential. Therefore for the forces with which
+  we are now concerned Xdx + Ydy + Zdz = dU, where U is some function of
+  x, y, z, and it is necessary for equilibrium that dp = [rho]dU be a
+  complete differential; that is, [rho] must be a function of U or a
+  function of p, and so also p a function of U. So that dU = 0 is the
+  differential equation of surfaces of equal pressure and density.
+
+  We may now show that a homogeneous fluid mass in the form of an oblate
+  ellipsoid of revolution having a uniform velocity of rotation can be
+  in equilibrium. It may be proved that the attraction of the ellipsoid
+  x squared + y squared + z squared(1 + [epsilon] squared) = c squared(1 + [epsilon] squared); upon a particle P
+  of its mass at x, y, z has for components
+
+    X = -Ax, Y = -Ay, Z = -Cz,
+
+  where
+
+                     /1 + [epsilon] squared                        1     \
+    A = 2[pi]k squared[rho]( ------------- tan^(-1) [epsilon] - --------  ),
+                     \  [epsilon] cubed                      [epsilon] squared/
+
+                     /1 + [epsilon] squared   1 + [epsilon] squared                  \
+    C = 4[pi]k squared[rho]( -------------- - ------------- tan^(-1) [epsilon] ),
+                     \  [epsilon] squared      [epsilon] cubed                     /
+
+  and k squared the constant of attraction. Besides the attraction of the mass
+  of the ellipsoid, the centrifugal force at P has for components +
+  x[omega] squared, + y[omega] squared, 0; then the condition of fluid equilibrium is
+
+    (A - [omega] squared)xdx + (A - [omega] squared)ydy + Czdz = 0,
+
+  which by integration gives
+
+    (A - [omega] squared)(x squared + y squared) + Cz squared = constant.
+
+  This is the equation of an ellipsoid of rotation, and therefore the
+  equilibrium is possible. The equation coincides with that of the
+  surface of the fluid mass if we make
+
+    A - [omega] squared = C/(1 + [epsilon] squared),
+
+  which gives
+
+      [omega] squared     3 + [epsilon] squared                           3
+    ------------ = -------------- tan^(-1) [epsilon] - ---------- .
+    2[pi]k squared[rho]     [epsilon] cubed                        [epsilon] squared
+
+  In the case of the earth, which is nearly spherical, we obtain by
+  expanding the expression for [omega] squared in powers of [epsilon] squared,
+  rejecting the higher powers, and remarking that the ellipticity e =
+  1/2[epsilon] squared,
+
+    [omega] squared/2[pi]k squared[rho] = 4[epsilon] squared/15 = 8e/15.
+
+  Now if m be the ratio of the centrifugal force to the intensity of
+  gravity at the equator, and a = c(1 + e), then
+
+    m = a[omega] squared,/(4/3)[pi]k squared[rho]a, :. [omega] squared/2[pi]k squared[rho] = (2/3)m.
+
+  In the case of the earth it is a matter of observation that m =
+  1/289, hence the ellipticity
+
+    e = 5m/4 = 1/231,
+
+  so that the ratio of the axes on the supposition of a homogeneous
+  fluid earth is 230:231, as stated by Newton.
+
+  Now, to come to the case of a heterogeneous fluid, we shall assume
+  that its surfaces of equal density are spheroids, concentric and
+  having a common axis of rotation, and that the ellipticity of these
+  surfaces varies from the centre to the outer surface, the density also
+  varying. In other words, the body is composed of homogeneous
+  spheroidal shells of variable density and ellipticity. On this
+  supposition we shall express the attraction of the mass upon a
+  particle in its interior, and then, taking into account the
+  centrifugal force, form the equation expressing the condition of fluid
+  equilibrium. The attraction of the homogeneous spheroid x squared + y squared + z squared(1
+  + 2e) = c squared(1 + 2e), where e is the ellipticity (of which the square is
+  neglected), on an internal particle, whose co-ordinates are x = f, y =
+  0, z = h, has for its x and z components
+
+    X' = -(4/3)[pi]k squared[rho]f(1 - (2/5)e),
+    Z' = -(4/3)[pi]k squared[rho]h(1 + (4/5)e),
+
+  the Y component being of course zero. Hence we infer that the
+  attraction of a shell whose inner surface has an ellipticity e, and
+  its outer surface an ellipticity e + de, the density being [rho], is
+  expressed by
+
+    dX' = (4/3).(2/5)[pi]k squared[rho]f de, dZ' = -(4/3).(4/5)[pi]k squared[rho]h de.
+
+  To apply this to our heterogeneous spheroid; if we put c1 for the
+  semiaxis of that surface of equal density on which is situated the
+  attracted point P, and c0 for the semiaxis of the outer surface, the
+  attraction of that portion of the body which is exterior to P, namely,
+  of all the shells which enclose P, has for components
+                    _                               _
+          8        /c0     de           16         /c0     de
+    X0 = --[pi]k squaredf | [rho] --dc, Z0 = - -- [pi]k squaredh | [rho] --dc,
+         15       _/c1     dc           15        _/c1     dc
+
+  both e and [rho] being functions of c. Again the attraction of a
+  homogeneous spheroid of density [rho] on an _external_ point f, h has
+  the components
+
+    X" = -(4/3)[pi]k squared[rho]fr^(-3) {c cubed(1 + 2e) - [lambda]ec^5},
+    Z" = -(4/3)[pi]k squared[rho]hr^(-3) {c cubed(1 + 2e) - [lambda]'ec^5},
+
+  where [lambda] = (3/5)(4h squared - f squared)/r^4,
+        [lambda]' = (3/5)(2h squared - 3f squared)/r^4, and r squared = f squared + h squared.
+
+  Now e being considered a function of c, we can at once express the
+  attraction of a shell (density [rho]) contained between the surface
+  defined by c + dc, e + de and that defined by c, e upon an external
+  point; the differentials with respect to c, viz. dX" dZ", must then
+  be integrated with [rho] under the integral sign as being a function
+  of c. The integration will extend from c = 0 to c = c1. Thus the
+  components of the attraction of the heterogeneous spheroid upon a
+  particle within its mass, whose co-ordinates are f, 0, h, are
+                      _     _
+          4          | 1   /c1
+    X = - -- [pi]k squaredf | --  | [rho] d{c cubed(1 + 2e)}
+          3          |_r cubed _/0
+
+                  _                    _        _
+        [lambda] /c1               2  /c1        |
+      - -------- | [rho] d(ec^5) - -- | [rho] de |,
+           r cubed   _/0                5 _/0        _|
+                      _     _
+          4          | 1   /c1
+    Z = - -- [pi]k squaredh | --  | [rho] d{c cubed(1 + 2e)}
+          3          |_r cubed _/0
+
+                  _                    _        _
+        [lambda]'/c1               4  /c1        |
+      - -------- | [rho] d(ec^5) + -- | [rho] de |.
+           r cubed   _/0                5 _/0        _|
+
+  We take into account the rotation of the earth by adding the
+  centrifugal force f[omega] squared = F to X. Now, the surface of constant
+  density upon which the point f, 0, h is situated gives (1 - 2e) fdf +
+  hdh = 0; and the condition of equilibrium is that (X + F)df + Zdh = 0.
+  Therefore,
+
+    (X + F)h = Zf(1 - 2e),
+
+  which, neglecting small quantities of the order e squared and putting
+  [omega] squaredt squared = 4[pi] squaredk squared, gives
+        _                            _                   _
+    2e /c1                     6    /c1              6  /c0         3[pi]
+    -- | [rho]d{c cubed(1 + 2e)} - ----  | [rho]d(ec^5) - -- | [rho]de = -----.
+    r cubed_/0                     5r^5 _/0               5 _/c1           t squared
+
+  Here we must now put c for c1, c for r; and 1 + 2e under the first
+  integral sign may be replaced by unity, since small quantities of the
+  second order are neglected. Two differentiations lead us to the
+  following very important differential equation (Clairault):
+
+    d squarede      2[rho]c squared      de    /    2[rho]c      6 \
+    --- + -------------- . -- + ( -------------- - -- ) e = 0.
+    dc squared   [int][rho]c squareddc   dc    \[int][rho]c squareddc   c squared/
+
+  When [rho] is expressed in terms of c, this equation can be
+  integrated. We infer then that a rotating spheroid of very small
+  ellipticity, composed of fluid homogeneous strata such as we have
+  specified, will be in equilibrium; and when the law of the density is
+  expressed, the law of the corresponding ellipticities will follow.
+
+  If we put M for the mass of the spheroid, then
+               _
+        4[pi] /c                             c cubed   4[pi] squared
+    M = ----- | [rho]d{c cubed(1 + 2e)}; and m = --- . -----,
+          3  _/0                             M      t squared
+
+  and putting c = c0 in the equation expressing the condition of
+  equilibrium, we find
+                             _
+                4        6  /c
+    M(2e - m) = -- [pi].--- | [rho]d(ec^5).
+                3       5c squared_/0
+
+  Making these substitutions in the expressions for the forces at the
+  surface, and putting r/c = 1 + e - e(h/c) squared, we get
+                       _                             _
+                  Mk squared |         3       /5      \  h squared | f
+    G cos [phi] = --- | 1 - e - -- m + ( - m - 2e) -- | --
+                  ac  |_        2       \2      /  c squared_| c
+                       _                             _
+                  Mk squared |         3       /5      \  h squared | h
+    G sin [phi] = --- | 1 + e - -- m + ( - m - 2e) -- | --.
+                  ac  |_        2       \2      /  c squared_| c
+
+  Here G is gravity in the latitude [phi], and a the radius of the
+  equator. Since
+
+    sec [phi] = (c/f){1 + e + (eh squared/c squared)},
+             _                                 _
+        Mk squared |     3       /5      \             |
+    G = --- | 1 - -- m + ( -- m - e) sin squared [phi] |,
+        ac  |_    2       \2      /            _|
+
+  an expression which contains the theorems we have referred to as
+  discovered by Clairault.
+
+  The theory of the figure of the earth as a rotating ellipsoid has been
+  especially investigated by Laplace in his _Mecanique celeste_. The
+  principal English works are:--Sir George Airy, _Mathematical Tracts_,
+  a lucid treatment without the use of Laplace's coefficients;
+  Archdeacon Pratt's _Attractions and Figure of the Earth_; and
+  O'Brien's _Mathematical Tracts_; in the last two Laplace's
+  coefficients are used.
+
+In 1845 Sir G.G. Stokes (_Camb. Trans._ viii.; see also _Camb. Dub.
+Math. Journ._, 1849, iv.) proved that if the external form of the
+sea--imagined to percolate the land by canals--be a spheroid with small
+ellipticity, then the law of gravity is that which we have shown above;
+his proof required no assumption as to the ellipticity of the internal
+strata, or as to the past or present fluidity of the earth. This
+investigation admits of being regarded conversely, viz. as determining
+the elliptical form of the earth from measurements of gravity; if G, the
+observed value of gravity in latitude [phi], be expressed in the form G
+= g(1 + ss sin squared [phi]), where g is the value at the equator and ss a
+coefficient. In this investigation, the square and higher powers of the
+ellipticity are neglected; the solution was completed by F.R. Helmert
+with regard to the square of the ellipticity, who showed that a term
+with sin squared 2[phi] appeared (see Helmert, _Geodaesie_, ii. 83). For the
+coefficient of this term, the gravity measurements give a small but not
+sufficiently certain value; we therefore assume a value which agrees
+best with the hypothesis of the fluid state of the entire earth; this
+assumption is well supported, since even at a depth of only 50 km. the
+pressure of the superincumbent crust is so great that rocks become
+plastic, and behave approximately as fluids, and consequently the crust
+of the earth floats, to some extent, on the interior (even though this
+may not be fluid in the usual sense of the word). This is the geological
+theory of "Isostasis" (cf. GEOLOGY); it agrees with the results of
+measurements of gravity (_vide infra_), and was brought forward in the
+middle of the 19th century by J.H. Pratt, who deduced it from
+observations made in India.
+
+The sin squared 2[phi] term in the expression for G, and the corresponding
+deviation of the meridian from an ellipse, have been analytically
+established by Sir G.H. Darwin and E. Wiechert; earlier and less
+complete investigations were made by Sir G.B. Airy and O. Callandreau.
+In consequence of the sin squared 2[phi] term, two parameters of the level
+surfaces in the interior of the earth are to be determined; for this
+purpose, Darwin develops two differential equations in the place of the
+one by Clairault. By assuming Roche's law for the variation of the
+density in the interior of the Earth, viz. [rho] = [rho]1 - k(c/c1) squared, k
+being a coefficient, it is shown that in latitude 45 deg., the meridian is
+depressed about 31/4 metres from the ellipse, and the coefficient of the
+term sin squared [phi] cos squared [phi] (= 1/4 sin squared 2[phi]) is -0.0000295. According to
+Wiechert the earth is composed of a kernel and a shell, the kernel being
+composed of material, chiefly metallic iron, of density near 8.2, and
+the shell, about 900 miles thick, of silicates, &c., of density about
+3.2. On this assumption the depression in latitude 45 deg. is 23/4 metres, and
+the coefficient of sin squared [phi] cos squared [phi] is, in round numbers,
+-0.0000280.[2] To this additional term in the formula for G, there
+corresponds an extension of Clairault's formula for the calculation of
+the flattening from ss with terms of the higher orders; this was first
+accomplished by Helmert.
+
+For a long time the assumption of an ellipsoid with three unequal axes
+has been held possible for the figure of the earth, in consequence of an
+important theorem due to K.G. Jacobi, who proved that for a homogeneous
+fluid in rotation a spheroid is not the only form of equilibrium; an
+ellipsoid rotating round its least axis may with certain proportions of
+the axes and a certain time of revolution be a form of equilibrium.[3]
+It has been objected to the figure of three unequal axes that it does
+not satisfy, in the proportions of the axes, the conditions brought out
+in Jacobi's theorem (c: a < 1/[root]2). Admitting this, it has to be
+noted, on the other hand, that Jacobi's theorem contemplates a
+homogeneous fluid, and this is certainly far from the actual condition
+of our globe; indeed the irregular distribution of continents and oceans
+suggests the possibility of a sensible divergence from a perfect surface
+of revolution. We may, however, assume the ellipsoid with three unequal
+axes to be an interpolation form. More plausible forms are little
+adapted for computation.[4] Consequently we now generally take the
+ellipsoid of rotation as a basis, especially so because measurements of
+gravity have shown that the deviation from it is but trifling.
+
+
+_Local Attraction._
+
+In speaking of the figure of the earth, we mean the surface of the sea
+imagined to percolate the continents by canals. That this surface
+should turn out, after precise measurements, to be exactly an ellipsoid
+of revolution is _a priori_ improbable. Although it may be highly
+probable that originally the earth was a fluid mass, yet in the cooling
+whereby the present crust has resulted, the actual solid surface has
+been left most irregular in form. It is clear that these irregularities
+of the visible surface must be accompanied by irregularities in the
+mathematical figure of the earth, and when we consider the general
+surface of our globe, its irregular distribution of mountain masses,
+continents, with oceans and islands, we are prepared to admit that the
+earth may not be precisely any surface of revolution. Nevertheless,
+there must exist some spheroid which agrees very closely with the
+mathematical figure of the earth, and has the same axis of rotation. We
+must conceive this figure as exhibiting slight departures from the
+spheroid, the two surfaces cutting one another in various lines; thus a
+point of the surface is defined by its latitude, longitude, and its
+height above the "spheroid of reference." Calling this height N, then of
+the actual magnitude of this quantity we can generally have no
+information, it only obtrudes itself on our notice by its variations. In
+the vicinity of mountains it may change sign in the space of a few
+miles; N being regarded as a function of the latitude and longitude, if
+its differential coefficient with respect to the former be zero at a
+certain point, the normals to the two surfaces then will lie in the
+prime vertical; if the differential coefficient of N with respect to the
+longitude be zero, the two normals will lie in the meridian; if both
+coefficients are zero, the normals will coincide. The comparisons of
+terrestrial measurements with the corresponding astronomical
+observations have always been accompanied with discrepancies. Suppose A
+and B to be two trigonometrical stations, and that at A there is a
+disturbing force drawing the vertical through an angle [delta], then it
+is evident that the apparent zenith of A will be really that of some
+other place A', whose distance from A is r[delta], when r is the earth's
+radius; and similarly if there be a disturbance at B of the amount
+[delta]', the apparent zenith of B will be really that of some other
+place B', whose distance from B is r[delta]'. Hence we have the
+discrepancy that, while the geodetic measurements deal with the points A
+and B, the astronomical observations belong to the points A', B'. Should
+[delta], [delta]' be equal and parallel, the displacements AA', BB' will
+be equal and parallel, and no discrepancy will appear. The
+non-recognition of this circumstance often led to much perplexity in the
+early history of geodesy. Suppose that, through the unknown variations
+of N, the probable error of an observed latitude (that is, the angle
+between the normal to the mathematical surface of the earth at the given
+point and that of the corresponding point on the spheroid of reference)
+be [epsilon], then if we compare two arcs of a degree each in mean
+latitudes, and near each other, say about five degrees of latitude
+apart, the probable error of the resulting value of the ellipticity will
+be approximately +- 1/500[epsilon], [epsilon] being expressed in
+seconds, so that if [epsilon] be so great as 2" the probable error of
+the resulting ellipticity will be greater than the ellipticity itself.
+
+It is necessary at times to calculate the attraction of a mountain, and
+the consequent disturbance of the astronomical zenith, at any point
+within its influence. The deflection of the plumb-line, caused by a
+local attraction whose amount is k squaredA[delta], is measured by the ratio of
+k squaredA[delta] to the force of gravity at the station. Expressed in seconds,
+the deflection [Lambda] is
+
+  [Lambda] = 12".447A[delta]/[rho],
+
+where [rho] is the mean density of the earth, [delta] that of the
+attracting mass, and A = [f]s^(-3)xdv, in which dv is a volume element
+of the attracting mass within the distance s from the point of
+deflection, and x the projection of s on the horizontal plane through
+this point, the linear unit in expressing A being a mile. Suppose, for
+instance, a table-land whose form is a rectangle of 12 miles by 8 miles,
+having a height of 500 ft. and density half that of the earth; let the
+observer be 2 miles distant from the middle point of the longer side.
+The deflection then is 1".472; but at 1 mile it increases to 2".20.
+
+At sixteen astronomical stations in the English survey the disturbance
+of latitude due to the form of the ground has been computed, and the
+following will give an idea of the results. At six stations the
+deflection is under 2", at six others it is between 2" and 4", and at
+four stations it exceeds 4". There is one very exceptional station on
+the north coast of Banffshire, near the village of Portsoy, at which the
+deflection amounts to 10", so that if that village were placed on a map
+in a position to correspond with its astronomical latitude, it would be
+1000 ft. out of position! There is the sea to the north and an
+undulating country to the south, which, however, to a spectator at the
+station does not suggest any great disturbance of gravity. A somewhat
+rough estimate of the local attraction from external causes gives a
+maximum limit of 5", therefore we have 5" which must arise from
+unequal density in the underlying strata in the surrounding country. In
+order to throw light on this remarkable phenomenon, the latitudes of a
+number of stations between Nairn on the west, Fraserburgh on the east,
+and the Grampians on the south, were observed, and the local deflections
+determined. It is somewhat singular that the deflections diminish in all
+directions, not _very_ regularly certainly, and most slowly in a
+south-west direction, finally disappearing, and leaving the maximum at
+the original station at Portsoy.
+
+The method employed by Dr C. Hutton for computing the attraction of
+masses of ground is so simple and effectual that it can hardly be
+improved on. Let a horizontal plane pass through the given station; let
+r, [theta] be the polar co-ordinates of any point in this plane, and r,
+[theta], z, the co-ordinates of a particle of the attracting mass; and
+let it be required to find the attraction of a portion of the mass
+contained between the horizontal planes z = 0, z = h, the cylindrical
+surfaces r = r1, r = r2, and the vertical planes [theta] = [theta]1,
+[theta] = [theta]2. The component of the attraction at the station or
+origin along the line [theta] = 0 is
+             _    _          _
+            /r2  /[theta]2  /h  r squaredcos [theta]
+  k squared[delta] |    |          |   ------------- dr d[theta] dz
+           _/r1 _/[theta]1 _/0  (r squared+z squared)^(3/2)
+
+    = k squared[delta]h(sin[theta]2 - sin[theta]1) log{r2 + (r2 squared + h squared)^(1/2)/r1 + (r1 squared + h squared)^(1/2)}.
+
+By taking r2 - r1, sufficiently small, and supposing h also small
+compared with r1 + r2 (as it usually is), the attraction is
+
+  k squared[delta](r2 - r1)(sin [theta]2 - sin [theta]1)h/r,
+
+where r= 1/2(r1 + r2). This form suggests the following procedure. Draw on
+the contoured map a series of equidistant circles, concentric with the
+station, intersected by radial lines so disposed that the sines of their
+azimuths are in arithmetical progression. Then, having estimated from
+the map the mean heights of the various compartments, the calculation is
+obvious.
+
+In mountainous countries, as near the Alps and in the Caucasus,
+deflections have been observed to the amount of as much as 30", while
+in the Himalayas deflections amounting to 60" were observed. On the
+other hand, deflections have been observed in flat countries, such as
+that noted by Professor K.G. Schweizer, who has shown that, at certain
+stations in the vicinity of Moscow, within a distance of 16 miles the
+plumb-line varies 16" in such a manner as to indicate a vast deficiency
+of matter in the underlying strata; deflections of 10" were observed in
+the level regions of north Germany.
+
+Since the attraction of a mountain mass is expressed as a numerical
+multiple of [delta] : [rho] the ratio of the density of the mountain to
+that of the earth, if we have any independent means of ascertaining the
+amount of the deflection, we have at once the ratio [rho]:[delta], and
+thus we obtain the mean density of the earth, as, for instance, at
+Schiehallion, and afterwards at Arthur's Seat. Experiments of this kind
+for determining the mean density of the earth have been made in greater
+numbers; but they are not free from objection (see GRAVITATION).
+
+Let us now consider the perturbation attending a spherical subterranean
+mass. A compact mass of great density at a small distance under the
+surface of the earth will produce an elevation of the mathematical
+surface which is expressed by the formula
+
+  y = a mu((1 - 2u cos [theta] + u squared)^(-1/2) - 1),
+
+where a is the radius of the (spherical) earth, a(1 - u) the distance
+of the disturbing mass below the surface,  mu the ratio of the disturbing
+mass to the mass of the earth, and a[theta] the distance of any point on
+the surface from that point, say Q, which is vertically over the
+disturbing mass. The maximum value of y is at Q, where it is y = a muu(1
+-u). The deflection at the distance a[theta] is [Lambda] =  muu
+sin[theta](1 - 2u cos[theta] + u squared)^(-3/2), or since [theta] is small,
+putting h + u = 1, we have [Lambda] =  mu[theta](h squared + [theta] squared)^(-3/2).
+The maximum deflection takes place at a point whose distance from Q is
+to the depth of the mass as 1:[root]2, and its amount is 2 mu/3
+[root](3h squared). If, for instance, the disturbing mass were a sphere a mile
+in diameter, the excess of its density above that of the surrounding
+country being equal to half the density of the earth, and the depth of
+its centre half a mile, the greatest deflection would be 5", and the
+greatest value of y only two inches. Thus a large disturbance of gravity
+may arise from an irregularity in the mathematical surface whose actual
+magnitude, as regards height at least, is extremely small.
+
+The effect of the disturbing mass  mu on the vibrations of a pendulum
+would be a maximum at Q; if v be the number of seconds of time gained
+per diem by the pendulum at Q, and [sigma] the number of seconds of
+angle in the maximum deflection, then it may be shown that v/[sigma] =
+[pi][root]3/10.
+
+The great Indian survey, and the attendant measurements of the degree of
+latitude, gave occasion to elaborate investigations of the deflection of
+the plumb-line in the neighbourhood of the high plateaus and mountain
+chains of Central Asia. Archdeacon Pratt (_Phil. Trans._, 1855 and
+1857), in instituting these investigations, took into consideration the
+influence of the apparent diminution of the mass of the earth's crust
+occasioned by the neighbouring ocean-basins; he concluded that the
+accumulated masses of mountain chains, &c., corresponded to subterranean
+mass diminutions, so that over any level surface in a fixed depth
+(perhaps 100 miles or more) the masses of prisms of equal section are
+equal. This is supported by the gravity measurements at More in the
+Himalayas at a height of 4696 metres, which showed no deflection due to
+the mountain chain (_Phil. Trans._, 1871); more recently, H.A. Faye
+(_Compt. rend._, 1880) arrived at the same conclusion for the entire
+continent.
+
+This compensation, however, must only be regarded as a general
+principle; in certain cases, the compensating masses show marked
+horizontal displacements. Further investigations, especially of gravity
+measurements, will undoubtedly establish other important facts. Colonel
+S.G. Burrard has recently recalculated, with the aid of more exact data,
+certain Indian deviations of the plumb-line, and has established that in
+the region south of the Himalayas (lat. 24 deg.) there is a subterranean
+perturbing mass. The extent of the compensation of the high mountain
+chains is difficult to recognize from the latitude observations, since
+the same effect may result from different causes; on the other hand,
+observations of geographical longitude have established a strong
+compensation.[5]
+
+
+_Meridian Arcs._
+
+The astronomical stations for the measurement of the degree of latitude
+will generally lie not exactly on the same meridian; and it is therefore
+necessary to calculate the arcs of meridian M which lie between the
+latitude of neighbouring stations. If S be the geodetic line calculated
+from the triangulation with the astronomically determined azimuths
+[alpha]1 and [alpha]2, then
+                             _                                _
+            cos [alpha]     |      1    S squared                     |
+  M = S ------------------- | 1 + -- -------- sin squared [alpha] ... |,
+        cos 1/2[Delta][alpha] |_    12 [alpha] squared                 _|
+
+in which 2[alpha] = [alpha]1 + [alpha]2 - 180 deg., [Delta][alpha] =
+[alpha]2 - [alpha]1 - 180 deg..
+
+The length of the arc of meridian between the latitudes [phi]1 and
+[phi]2 is
+
+       _[phi]2                 _[phi]2
+      /                       /         (1 - e squared)d[phi]
+  M = | [rho]d[phi] = [alpha] |     -----------------------
+     _/                      _/     (1 - e squaredsin squared[phi])^(3/2)
+      [phi]1                  [phi]1
+
+where a squarede squared = a squared - b squared; instead of using the eccentricity e, put the ratio
+of the axes b:a = 1 - n:1 + n, then
+
+       _[phi]2
+      /         b(1 + n)(1 - n squared)d[phi]
+  M = |     ------------------------------.
+     _/     (1 + 2n cos 2[phi] + n squared)^(3/2)
+      [phi]1
+
+This, after integration, gives
+
+         /        5      5 \              /            21 \
+  M/b = ( 1 + n + -n squared  + -n cubed) [alpha]0 - ( 3n +  3n squared + --n cubed) [alpha]1
+         \        4      4 /              \             8 /
+
+       /15     15 \              /35  \
+    + ( --n squared + --n cubed) [alpha]2 - ( --n cubed ) [alpha]3,
+       \ 8      8 /              \24  /
+
+where
+
+  [alpha]0 = [phi]2 -  [phi]1
+  [alpha]1 = sin ([phi]2 - [phi]1) cos ([phi]2 + [phi]1)
+  [alpha]2 = sin 2([phi]2 - [phi]1) cos 2([phi]2 + [phi]1)
+  [alpha]3 = sin 3([phi]2 - [phi]1) cos 3([phi]2 + [phi]1).
+
+The part of M which depends on n cubed is very small; in fact, if we
+calculate it for one of the longest arcs measured, the Russian arc, it
+amounts to only an inch and a half, therefore we omit this term, and put
+for M/b the value
+
+   /       5  \                                    /15 \
+  (l + n + --n squared) [alpha]0 - (3n + 3n squared) [alpha]1 + ( --n squared) [alpha]2.
+   \       4  /                                    \ 8 /
+
+Now, if we suppose the observed latitudes to be affected with errors,
+and that the true latitudes are [phi]1 + x1, [phi]2 + x2; and if further
+we suppose that n1 + dn is the true value of a - b:a + b, and that n1
+itself is merely a very approximate numerical value, we get, on making
+these substitutions and neglecting the influence of the corrections x on
+the _position_ of the arc in latitude, i.e. on [phi]1 + [phi]2,
+
+         /           5   \             /        \             /15  \
+  M/b = ( 1 + n    + --n1 squared)[alpha]0 - (3n1 + 3n1 squared)[alpha]1 + ( --n1 squared)[alpha]2
+         \           4   /             \        /             \8   /
+       _                                             _
+      |  /    5    \       /       \       /15   \    |
+    + | ( 1 + -- n1 )a0 - ( 3 + 6n1 )a1 + ( -- n1 )a2 | dn
+      |_ \    2    /       \       /       \4    /   _|
+       _               _
+      |             da1 |
+    + | 1 + n1 - 3n --- | da0;
+      |_            da0_|
+
+here da0 = x2 - x1; and as b is only known approximately, put b = b1(1 +
+u); then we get, after dividing through by the coefficient of da0, which
+is = 1 + n1 - 3n1 cos([phi]2 - [phi]1) cos([phi]2 + [phi]1), an equation
+of the form x2 = x1 + h + fu + gv, where for convenience we put v for
+dn.
+
+Now in every measured arc there are not only the extreme stations
+determined in latitude, but also a number of intermediate stations so
+that if there be i + 1 stations there will be i equations
+
+  x2 = x1 + f1u + g1v + h1
+  x3 = x1 + f2u + g2v + h2
+   :    :                :
+   :    :                :
+  x_i = x1 + f_iu + g_iv + h_i
+
+In combining a number of different arcs of meridian, with the view of
+determining the figure of the earth, each arc will supply a number of
+equations in u and v and the corrections to its observed latitudes.
+Then, according to the method of least squares, those values of u and v
+are the most probable which render the sum of the squares of _all_ the
+errors x a minimum. The corrections x which are here applied arise not
+from errors of observation only. The mere uncertainty of a latitude, as
+determined with modern instruments, does not exceed a very small
+fraction of a second as far as errors of observation go, but no accuracy
+in observing will remove the error that may arise from local attraction.
+This, as we have seen, may amount to some seconds, so that the
+corrections x to the observed latitudes are attributable to local
+attraction. Archdeacon Pratt objected to this mode of applying least
+squares first used by Bessel; but Bessel was right, and the objection is
+groundless. Bessel found, in 1841, from ten meridian arcs with a total
+amplitude of 50 deg..6:
+
+  a = 3272077 toises = 6377397 metres.
+  e (ellipticity) = (a - b)/a = 1/299.15 (prob. error +- 3.2).
+
+The probable error in the length of the earth's quadrant is +- 336 m.
+
+We now give a series of some meridian-arcs measurements, which were
+utilized in 1866 by A.R. Clarke in the _Comparisons of the Standards of
+Length_, pp. 280-287; details of the calculations are given by the same
+author in his _Geodesy_ (1880), pp. 311 et seq.
+
+The data of the French arc from Formentera to Dunkirk are--
+
+  Stations.        Astronomical       Distance of
+                     Latitudes.        Parallels.
+                     deg.   '    "             Ft.
+  Formentera       38  39  53.17            ..
+  Mountjouy        41  21  44.96         982671.04
+  Barcelona        41  22  47.90         988701.92
+  Carcassonne      43  12  54.30        1657287.93
+  Pantheon         48  50  47.98        3710827.13
+  Dunkirk          51   2   8.41        4509790.84
+
+The distance of the parallels of Dunkirk and Greenwich, deduced from the
+extension of the triangulation of England into France, in 1862, is
+161407.3 ft., which is 3.9 ft. greater than that obtained from Captain
+Kater's triangulation, and 3.2 ft. less than the distance calculated by
+Delambre from General Roy's triangulation. The following table shows the
+data of the English arc with the distances in standard feet from
+Formentera.
+
+                     deg.   '    "             Ft.
+  Formentera            ..                  ..
+  Greenwich        51  28  38.30         4671198.3
+  Arbury           52  13  26.59         4943837.6
+  Clifton          53  27  29.50         5394063.4
+  Kellie Law       56  14  53.60         6413221.7
+  Stirling         57  27  49.12         6857323.3
+  Saxavord         60  49  37.21         8086820.7
+
+The latitude assigned in this table to Saxavord is not the directly
+observed latitude, which is 60 deg. 49' 38.58", for there are here a
+cluster of three points, whose latitudes are astronomically determined;
+and if we transfer, by means of the geodesic connexion, the latitude of
+Gerth of Scaw to Saxavord, we get 60 deg. 49' 36.59"; and if we similarly
+transfer the latitude of Balta, we get 60 deg. 49' 36.46". The mean of
+these three is that entered in the above table.
+
+For the Indian arc in long. 77 deg. 40' we have the following data:--
+
+                     deg.   '     "             Ft.
+  Punnea            8   9   31.132          ..
+  Putchapolliam    10  59   42.276       1029174.9
+  Dodagunta        12  59   52.165       1756562.0
+  Namthabad        15   5   53.562       2518376.3
+  Daumergida       18   3   15.292       3591788.4
+  Takalkhera       21   5   51.532       4697329.5
+  Kalianpur        24   7   11.262       5794695.7
+  Kaliana          29  30   48.322       7755835.9
+
+The data of the Russian arc (long. 26 deg. 40') taken from Struve's work are
+as below:--
+
+                     deg.   '    "              Ft.
+  Staro Nekrasovsk 45  20   2.94            ..
+  Vodu-Luy         47   1  24.98         616529.81
+  Suprunkovzy      48  45   3.04        1246762.17
+  Kremenets        50   5  49.95        1737551.48
+  Byelin           52   2  42.16        2448745.17
+  Nemesh           54  39   4.16        3400312.63
+  Jacobstadt       56  30   4.97        4076412.28
+  Dorpat           58  22  47.56        4762421.43
+  Hogland          60   5   9.84        5386135.39
+  Kilpi-maki       62  38   5.25        6317905.67
+  Tornea           65  49  44.57        7486789.97
+  Stuor-oivi       68  40  58.40        8530517.90
+  Fuglenaes        70  40  11.23        9257921.06
+
+From the are measured in Cape Colony by Sir Thomas Maclear in long. 18 deg.
+30', we have
+
+                         deg.   '     "         Ft.
+  North End            29  44   17.66       ..
+  Heerenlogement Berg  31  58    9.11     811507.7
+  Royal Observatory    33  56    3.20    1526386.8
+  Zwart Kop            34  13   32.13    1632583.3
+  Cape Point           34  21    6.26    1678375.7
+
+And, finally, for the Peruvian arc, in long. 281 deg. 0',
+
+                    deg.   '     "              Ft.
+  Tarqui           3   4   32.068           ..
+  Cotchesqui       0   2   31.387        1131036.3
+
+Having now stated the data of the problem, we may seek that oblate
+ellipsoid (spheroid) which best represents the observations. Whatever
+the real figure may be, it is certain that if we suppose it an ellipsoid
+with three unequal axes, the arithmetical process will bring out an
+ellipsoid, which will agree better with all the observed latitudes than
+any spheroid would, therefore we do not _prove_ that it is an ellipsoid;
+to prove this, arcs of longitude would be required. The result for the
+spheroid may be expressed thus:--
+
+  a = 20926062 ft. = 6378206.4 metres.
+  b = 20855121 ft. = 6356583.8 metres.
+  b : a = 293.98 : 294.98.
+
+As might be expected, the sum of the squares of the 40 latitude
+corrections, viz. 153.99, is greater in this figure than in that of
+three axes, where it amounts to 138.30. For this case, in the Indian arc
+the largest corrections are at Dodagunta, + 3.87", and at Kalianpur, -
+3.68". In the Russian arc the largest corrections are + 3.76", at
+Tornea, and - 3.31", at Staro Nekrasovsk. Of the whole 40 corrections,
+16 are under 1.0", 10 between 1.0" and 2.0", 10 between 2.0" and
+3.0", and 4 over 3.0". The probable error of an observed latitude is +-
+1.42"; for the spheroidal it would be very slightly larger. This
+quantity may be taken therefore as approximately the probable amount of
+local deflection.
+
+If [rho] be the radius of curvature of the meridian in latitude [phi],
+[rho]' that perpendicular to the meridian, D the length of a degree of
+the meridian, D' the length of a degree of longitude, r the radius drawn
+from the centre of the earth, V the angle of the vertical with the
+radius-vector, then
+
+             Ft.
+     [rho]  = 20890606.6          - 106411.5 cos 2[phi] + 225.8 cos 4[phi]
+     [rho]' = 20961607.3          -  35590.9 cos 2[phi] + 45.2 cos 4[phi]
+     D      = 364609.87           -  1857.14 cos 2[phi] + 3.94 cos 4[phi]
+     D'     = 365538.48 cos [phi] -   310.17 cos 3[phi] + 0.39 cos 5[phi]
+  Log r/a   = 9.9992645           + .0007374 cos 2[phi] - .0000019 cos 4[phi]
+     V      = 700.44" sin 2[phi] - 1.19" sin 4[phi].
+
+A.R. Clarke has recalculated the elements of the ellipsoid of the earth;
+his values, derived in 1880, in which he utilized the measurements of
+parallel arcs in India, are particularly in practice. These values
+are:--
+
+  a = 20926202 ft. = 6378249 metres,
+  b = 20854895 ft. = 6356515 metres,
+  b : a = 292.465 : 293.465.
+
+  The calculation of the elements of the ellipsoid of rotation from
+  measurements of the curvature of arcs in any given azimuth by means of
+  geographical longitudes, latitudes and azimuths is indicated in the
+  article GEODESY; reference may be made to _Principal Triangulation_,
+  Helmert's _Geodasie_, and the publications of the Kgl. Preuss. Geod.
+  Inst.:--_Lotabweichungen_ (1886), and _Die europ. Laengengradmessung in
+  52 deg. Br._ (1893). For the calculation of an ellipsoid with three
+  unequal axes see _Comparison of Standards_, preface; and for
+  non-elliptical meridians, _Principal Triangulation_, p. 733.
+
+
+_Gravitation-Measurements._
+
+According to Clairault's theorem (see above) the ellipticity e of the
+mathematical surface of the earth is equal to the difference (5/2)m -ss,
+where m is the ratio of the centrifugal force at the equator to gravity
+at the equator, and ss is derived from the formula G = g(1 + ss
+sin squared[phi]). Since the beginning of the 19th century many efforts have
+been made to determine the constants of this formula, and numerous
+expeditions undertaken to investigate the intensity of gravity in
+different latitudes. If m be known, it is only necessary to determine ss
+for the evaluation of e; consequently it is unnecessary to determine G
+absolutely, for the relative values of G at two known latitudes suffice.
+Such relative measurements are easier and more exact than absolute ones.
+In some cases the ordinary thread pendulum, i.e. a spherical bob
+suspended by a wire, has been employed; but more often a rigid metal
+rod, bearing a weight and a knife-edge on which it may oscillate, has
+been adopted. The main point is the constancy of the pendulum. From the
+formula for the time of oscillation of the mathematically ideal
+pendulum, t = 2 [pi] [root](l/G), l being the length, it follows that
+for two points G1/G2 = t2 squared/t1 squared.
+
+In 1808 J.B. Biot commenced his pendulum observations at several
+stations in western Europe; and in 1817-1825 Captain Louis de Freycinet
+and L.I. Duperrey prosecuted similar observations far into the southern
+hemisphere. Captain Henry Kater confined himself to British stations
+(1818-1819); Captain E. Sabine, from 1819 to 1829, observed similarly,
+with Kater's pendulum, at seventeen stations ranging from the West
+Indies to Greenland and Spitsbergen; and in 1824-1831, Captain Henry
+Foster (who met his death by drowning in Central America) experimented
+at sixteen stations; his observations were completed by Francis Baily in
+London. Of other workers in this field mention may be made of F.B. Luetke
+(1826-1829), a Russian rear-admiral, and Captains J.B. Basevi and W.T.
+Heaviside, who observed during 1865 to 1873 at Kew and at 29 Indian
+stations, particularly at More in the Himalayas at a height of 4696
+metres. Of the earlier absolute determinations we may mention those of
+Biot, Kater, and Bessel at Paris, London and Koenigsberg respectively.
+The measurements were particularly difficult by reason of the length of
+the pendulums employed, these generally being second-pendulums over 1
+metre long. In about 1880, Colonel Robert von Sterneck of Austria
+introduced the half-second pendulum, which permitted far quicker and
+more accurate work. The use of these pendulums spread in all countries,
+and the number of gravity stations consequently increased: in 1880 there
+were about 120, in 1900 there were about 1600, of which the greater
+number were in Europe. Sir E. Sabine[6] calculated the ellipticity to be
+1/288.5, a value shown to be too high by Helmert, who in 1884, with the
+aid of 120 stations, gave the value 1/299.26,[7] and in 1901, with about
+1400 stations, derived the value 1/298.3.[8] The reason for the
+excessive estimate of Sabine is that he did not take into account the
+systematic difference between the values of G for continents and
+islands; it was found that in consequence of the constitution of the
+earth's crust (Pratt) G is greater on small islands of the ocean than
+on continents by an amount which may approach to 0.3 cm. Moreover,
+stations in the neighbourhood of coasts shelving to deep seas have a
+surplus, but a little smaller. Consequently, Helmert conducted his
+calculations of 1901 for continents and coasts separately, and obtained
+G for the coasts 0.036 cm. greater than for the continents, while the
+value of ss remained the same. The mean value, reduced to continents, is
+
+  G = 978.03(1 + 0.005302 sin squared[phi] - 0.000007 sin squared 2[phi])cm/sec squared.
+
+The small term involving sin squared 2[phi] could not be calculated with
+sufficient exactness from the observations, and is therefore taken from
+the theoretical views of Sir G.H. Darwin and E. Wiechert. For the
+constant g = 978.03 cm. another correction has been suggested (1906) by
+the absolute determinations made by F. Kuehnen and Ph. Furtwaengler at
+Potsdam.[9]
+
+  A report on the pendulum measurements of the 19th century has been
+  given by Helmert in the _Comptes rendus des seances de la 13^e
+  conference generale de l'Association Geod. Internationale a Paris_
+  (1900), ii. 139-385.
+
+A difficulty presents itself in the case of the application of
+measurements of gravity to the determination of the figure of the earth
+by reason of the extrusion or standing out of the land-masses
+(continents, &c.) above the sea-level. The potential of gravity has a
+different mathematical expression outside the masses than inside. The
+difficulty is removed by assuming (with Sir G.G. Stokes) the vertical
+condensation of the masses on the sea-level, without its form being
+considerably altered (scarcely 1 metre radially). Further, the value of
+gravity (g) measured at the height H is corrected to sea-level by +
+2gH/R, where R is the radius of the earth. Another correction, due to P.
+Bouguer, is -(3/2)g[delta]H/[rho]R, where [delta] is the density of the
+strata of height H, and [rho] the mean density of the earth. These two
+corrections are represented in "Bouguer's Rule": g_H = g_s(1 - 2H/R +
+3[delta]H/2[rho]R), where g_H is the gravity at height H, and g_s the
+value at sea-level. This is supposed to take into account the attraction
+of the elevated strata or plateau; but, from the analytical method, this
+is not correct; it is also disadvantageous since, in general, the
+land-masses are compensated subterraneously, by reason of the isostasis
+of the earth's crust.
+
+In 1849 Stokes showed that the normal elevations N of the geoid towards
+the ellipsoid are calculable from the deviations [Delta]g of the
+acceleration of gravity, i.e. the differences between the observed g and
+the value calculated from the normal G formula. The method assumes that
+gravity is measured on the earth's surface at a sufficient number of
+points, and that it is conformably reduced. In order to secure the
+convergence of the expansions in spherical harmonics, it is necessary to
+assume all masses outside a surface parallel to the surface of the sea
+at a depth of 21 km. (= R x ellipticity) to be condensed on this surface
+(Helmert, _Geod._ ii. 172). In addition to the reduction with 2gH/R,
+there still result small reductions with mountain chains and coasts, and
+somewhat larger ones for islands. The sea-surface generally varies but
+very little by this condensation. The elevation (N) of the geoid is then
+equal to
+         _
+        /[pi]
+  N = R |  FG^(-1) [Delta]g_[psi] d[psi],
+       _/
+
+where [psi] is the spherical distance from the point N, and
+[Delta]g_[psi] denotes the mean value of [Delta]g for all points in the
+same distance [psi] around; F is a function of [psi], and has the
+following values:--
+
+  +-------+-------+
+  | [Psi]=|   F=  |
+  +-------+-------+
+  |    0 deg. |  1    |
+  |   10 deg. |  1.22 |
+  |   20 deg. |  0.94 |
+  |   30 deg. |  0.47 |
+  |   40 deg. | -0.06 |
+  |   50 deg. | -0.54 |
+  |   60 deg. | -0.90 |
+  |   70 deg. | -1.08 |
+  |   80 deg. | -1.08 |
+  |   90 deg. | -0.91 |
+  |  100 deg. | -0.62 |
+  |  110 deg. | -0.27 |
+  |  120 deg. | +0.08 |
+  |  130 deg. |  0.36 |
+  |  140 deg. |  0.53 |
+  |  150 deg. |  0.56 |
+  |  160 deg. |  0.46 |
+  |  170 deg. |  0.26 |
+  |  180 deg. |  0    |
+  +-------+-------+
+
+H. Poincare (_Bull. Astr._, 1901, p. 5) has exhibited N by means of
+Lame's functions; in this case the condensation is effected on an
+ellipsoidal surface, which approximates to the geoid. This condensation
+is, in practice, the same as to the geoid itself.
+
+If we imagine the outer land-masses to be condensed on the sea-level,
+and the inner masses (which, together with the outer masses, causes the
+deviation of the geoid from the ellipsoid) to be compensated in the
+sea-level by a disturbing stratum (which, according to Gauss, is
+possible), and if these masses of both kinds correspond at the point N
+to a stratum of thickness D and density [delta], then, according to
+Helmert (_Geod._ ii. 260) we have approximately
+
+             3  g   /[delta]D    \
+  [Delta]g = -- -- ( -------- - N ).
+             2  R   \  [rho]     /
+
+Since N slowly varies empirically, it follows that in restricted regions
+(of a few 100 km. in diameter) [Delta]g is a measure of the variation of
+D. By applying the reduction of Bouguer to g, D is diminished by H and
+only gives the thickness of the ideal disturbing mass which corresponds
+to the perturbations due to subterranean masses. [Delta]g has positive
+values on coasts, small islands, and high and medium mountain chains,
+and occasionally in plains; while in valleys and at the foot of mountain
+ranges it is negative (up to 0.2 cm.). We conclude from this that the
+masses of smaller density existing under high mountain chains lie not
+only vertically underneath but also spread out sideways.
+
+
+_The European Arc of Parallel in 52 deg. Lat._
+
+Many measurements of degrees of longitudes along central parallels in
+Europe were projected and partly carried out as early as the first half
+of the 19th century; these, however, only became of importance after the
+introduction of the electric telegraph, through which calculations of
+astronomical longitudes obtained a much higher degree of accuracy. Of
+the greatest moment is the measurement near the parallel of 52 deg. lat.,
+which extended from Valentia in Ireland to Orsk in the southern Ural
+mountains over 69 deg. long, (about 6750 km.). F.G.W. Struve, who is to be
+regarded as the father of the Russo-Scandinavian latitude-degree
+measurements, was the originator of this investigation. Having made the
+requisite arrangements with the governments in 1857, he transferred
+them to his son Otto, who, in 1860, secured the co-operation of England.
+A new connexion of England with the continent, via the English Channel,
+was accomplished in the next two years; whereas the requisite
+triangulations in Prussia and Russia extended over several decennaries.
+The number of longitude stations originally arranged for was 15; and the
+determinations of the differences in longitude were uniformly commenced
+by the Russian observers E.I. von Forsch, J.I. Zylinski, B. Tiele and
+others; Feaghmain (Valentia) being reserved for English observers. With
+the concluding calculation of these operations, newer determinations of
+differences of longitudes were also applicable, by which the number of
+stations was brought up to 29. Since local deflections of the plumb-line
+were suspected at Feaghmain, the most westerly station, the longitude
+(with respect to Greenwich) of the trigonometrical station Killorglin at
+the head of Dingle Bay was shortly afterwards determined.
+
+  The results (1891-1894) are given in volumes xlvii. and l. of the
+  memoirs (Zapiski) of the military topographical division of the
+  Russian general staff, volume li. contains a reconnexion of Orsk. The
+  observations made west of Warsaw are detailed in the _Die europ.
+  Laengengradmessung in 52 deg. Br._, i. and ii., 1893, 1896, published by
+  the Kgl. Preuss. Geod. Inst.
+
+The following figures are quoted from Helmert's report "Die Groesse der
+Erde" (_Sitzb. d. Berl. Akad. d. Wiss._, 1906, p. 535):--
+
+  _Easterly Deviation of the Astronomical Zenith_.
+
+    Name.                   Longitude.
+                           deg.    '      "
+  Feaghmain             -10   21    -3.3
+  Killorglin            - 9   47    +2.8
+  Haverfordwest         - 4   58    +1.6
+  Greenwich               0    0    +1.5
+  Rosendael-Nieuport    + 2   35    -1.7
+  Bonn                  + 7    6    -4.4
+  Goettingen             + 9   57    -2.4
+  Brocken               +10   37    +2.3
+  Leipzig               +12   23    +2.7
+  Rauenberg-Berlin      +13   23    +1.7
+  Grossenhain           +13   33    -2.9
+  Schneekoppe           +15   45    +0.1
+  Springberg            +16   37    +0.8
+  Breslau-Rosenthal     +17    2    +3.5
+  Trockenberg           +18   53    -0.5
+  Schoensee              +18   54    -2.9
+  Mirov                 +19   18    +2.2
+  Warsaw                +21    2    +1.9
+  Grodno                +23   50    -2.8
+  Bobruisk              +29   14    +0.5
+  Orel                  +36    4    +4.4
+  Lipetsk               +39   36    +0.2
+  Saratov               +46    3    +6.4
+  Samara                +50    5    -2.6
+  Orenburg              +55    7    +1.7
+  Orsk                  +58   34    -8.0
+
+These deviations of the plumb-line correspond to an ellipsoid having an
+equatorial radius (a) of nearly 6,378,000 metres (prob. error +- 70
+metres) and an ellipticity 1/299.15. The latter was taken for granted;
+it is nearly equal to the result from the gravity-measurements; the
+value for a then gives [Sigma][eta] squared a minimum (nearly). The
+astronomical values of the geographical longitudes (with regard to
+Greenwich) are assumed, according to the compensation of longitude
+differences carried out by van de Sande Bakhuyzen (_Comp. rend, des
+seances de la commission permanente de l'Association Geod.
+Internationale a Geneve, 1893, annexe A.I._). Recent determinations
+(Albrecht, _Astr. Nach._, 3993/4) have introduced only small alterations
+in the deviations, a being slightly increased.
+
+Of considerable importance in the investigation of the great arc was
+the representation of the linear lengths found in different countries,
+in terms of the same unit. The necessity for this had previously
+occurred in the computation of the figure of the earth from
+latitude-degree-measurements. A.R. Clarke instituted an extensive
+series of comparisons at Southampton (see _Comparisons of Standards of
+Length of England, France, Belgium, Prussia, Russia, India and
+Australia, made at the Ordnance Survey Office, Southampton, 1866_, and
+a paper in the _Philosophical Transactions_ for 1873, by Lieut.-Col.
+A.R. Clarke, C.B., R.E., on the further comparisons of the standards
+of Austria, Spain, the United States, Cape of Good Hope and Russia) and
+found that 1 toise = 6.39453348 ft., 1 metre = 3.28086933 ft.
+
+In 1875 a number of European states concluded the metre convention, and
+in 1877 an international weights-and-measures bureau was established at
+Breteuil. Until this time the metre was determined by the end-surfaces
+of a platinum rod (_metre des archives_); subsequently, rods of
+platinum-iridium, of cross-section H, were constructed, having engraved
+lines at both ends of the bridge, which determine the distance of a
+metre. There were thirty of the rods which gave as accurately as
+possible the length of the metre; and these were distributed among the
+different states (see WEIGHTS AND MEASURES). Careful comparisons with
+several standard toises showed that the metre was not exactly equal to
+443,296 lines of the toise, but, in round numbers, 1/75000 of the length
+smaller. The metre according to the older relation is called the "legal
+metre," according to the new relation the "international metre." The
+values are (see _Europ. Laengengradmessung_, i. p. 230):--
+
+  Legal metre = 3.28086933 ft., International metre = 3.2808257 ft.
+
+The values of a given above are in terms of the international metre; the
+earlier ones in legal metres, while the gravity formulae are in
+international metres.
+
+
+_The International Geodetic Association (Internationale Erdmessung)._
+
+On the proposition of the Prussian lieutenant-general, Johann Jacob
+Baeyer, a conference of delegates of several European states met at
+Berlin in 1862 to discuss the question of a "Central European
+degree-measurement." The first general conference took place at Berlin
+two years later; shortly afterwards other countries joined the movement,
+which was then named "The European degree-measurement." From 1866 till
+1886 Prussia had borne the expense incident to the central bureau at
+Berlin; but when in 1886 the operations received further extension and
+the title was altered to "The International Earth-measurement" or
+"International Geodetic Association," the co-operating states made
+financial contributions to this purpose. The central bureau is
+affiliated with the Prussian Geodetic Institute, which, since 1892, has
+been situated on the Telegraphenberg near Potsdam. After Baeyer's death
+Prof. Friedrich Robert Helmert was appointed director. The funds are
+devoted to the advancement of such scientific works as concern all
+countries and deal with geodetic problems of a general or universal
+nature. During the period 1897-1906 the following twenty-one countries
+belonged to the association:--Austria, Belgium, Denmark, England,
+France, Germany, Greece, Holland, Hungary, Italy, Japan, Mexico, Norway,
+Portugal, Rumania, Russia, Servia, Spain, Sweden, Switzerland and the
+United States of America. At the present time general conferences take
+place every three years.[10]
+
+Baeyer projected the investigation of the curvature of the meridians and
+the parallels of the mathematical surface of the earth stretching from
+Christiania to Palermo for 12 degrees of longitude; he sought to
+co-ordinate and complete the network of triangles in the countries
+through which these meridians passed, and to represent his results by a
+common unit of length. This proposition has been carried out, and
+extended over the greater part of Europe; as a matter of fact, the
+network has, with trifling gaps, been carried over the whole of western
+and central Europe, and, by some chains of triangles, over European
+Russia. Through the co-operation of France, the network has been
+extended into north Africa as far as the geographical latitude of 32 deg.;
+in Greece a network, united with those of Italy and Bosnia, has been
+carried out by the Austrian colonel, Heinrich Hartl; Servia has
+projected similar triangulations; Rumania has begun to make the triangle
+measurements, and three base lines have been measured by French
+officers with Brunner's apparatus. At present, in Rumania, there is
+being worked a connexion between the arc of parallel in lat. 47 deg./48 deg. in
+Russia (stretching from Astrakan to Kishinev) with Austria-Hungary. In
+the latter country and in south Bavaria the connecting triangles for
+this parallel have been recently revised, as well as the French chain on
+the Paris parallel, which has been connected with the German net by the
+co-operation of German and French geodesists. This will give a long arc
+of parallel, really projected in the first half of the 19th century. The
+calculation of the Russian section gives, with an assumed ellipticity of
+1/299.15, the value a = 6377350 metres; this is rather uncertain, since
+the arc embraces only 19 deg. in longitude.
+
+We may here recall that in France geodetic studies have recovered their
+former expansion under the vigorous impulse of Colonel (afterwards
+General) Francois Perrier. When occupied with the triangulation of
+Algeria, Colonel Perrier had conceived the possibility of the geodetic
+junction of Algeria to Spain, over the Mediterranean; therefore the
+French meridian line, which was already connected with England, and was
+thus produced to the 60th parallel, could further be linked to the
+Spanish triangulation, cross thence into Algeria and extend to the
+Sahara, so as to form an arc of about 30 deg. in length. But it then became
+urgent to proceed to a new measurement of the French arc, between
+Dunkirk and Perpignan. In 1869 Perrier was authorized to undertake that
+revision. He devoted himself to that work till the end of his career,
+closed by premature death in February 1888, at the very moment when the
+_Depot de la guerre_ had just been transformed into the Geographical
+Service of the Army, of which General F. Perrier was the first director.
+His work was continued by his assistant, Colonel (afterwards General)
+J.A.L. Bassot. The operations concerning the revision of the French arc
+were completed only in 1896. Meanwhile the French geodesists had
+accomplished the junction of Algeria to Spain, with the help of the
+geodesists of the Madrid Institute under General Carlos Ibanez (1879),
+and measured the meridian line between Algiers and El Aghuat (1881).
+They have since been busy in prolonging the meridians of El Aghuat and
+Biskra, so as to converge towards Wargla, through Ghardaia and Tuggurt.
+The fundamental co-ordinates of the Pantheon have also been obtained
+anew, by connecting the Pantheon and the Paris Observatory with the five
+stations of Bry-sur-Marne, Morlu, Mont Valerien, Chatillon and
+Montsouris, where the observations of latitude and azimuth have been
+effected.[11]
+
+According to the calculations made at the central bureau of the
+international association on the great meridian arc extending from the
+Shetland Islands, through Great Britain, France and Spain to El Aghuat in
+Algeria, a = 6377935 metres, the ellipticity being assumed as 1/299.15.
+The following table gives the difference: astronomical-geodetic latitude.
+The net does not follow the meridian exactly, but deviates both to the
+west and to the east; actually, the meridian of Greenwich is nearer the
+mean than that of Paris (Helmert, _Groesse d. Erde_).
+
+  _West Europe-Africa Meridian-arc._[12]
+
+  Name.                Latitude.   A.-G.
+                         deg.   '        "
+  Saxavord             60  49.6    -4.0
+  Balta                60  45.0    -6.1
+  Ben Hutig            58  33.1    +0.3
+  Cowhythe             57  41.1    +7.3
+  Great Stirling       57  27.8    -2.3
+  Kellie Law           56  14.9    -3.7
+  Calton Hill          55  57.4    +3.5
+  Durham               54  46.1    -0.9
+  Burleigh Moor        54  34.3    +2.1
+  Clifton Beacon       53  27.5    +1.3
+  Arbury Hill          52  13.4    -3.0
+  Greenwich            51  28.6    -2.5
+  Nieuport             51   7.8    -0.4
+  Rosendael            51   2.7    -0.9
+  Lihons               49  49.9    +0.5
+  Pantheon             48  50.8    -0.0
+  Chevry               48   0.5    +2.2
+  Saligny le Vif       47   2.7    +3.0
+  Arpheuille           46  13.7    +6.3
+  Puy de Dome          45  46.5    +7.0
+  Rodez                44  21.4    +1.7
+  Carcassonne          43  13.3    +0.7
+  Rivesaltes           42  45.2    -0.7
+  Montolar             41  38.5    +3.6
+  Lerida               41  37.0    -0.2
+  Javalon              40  13.8    -0.2
+  Desierto             40   5.0    -4.5
+  Chinchilla           38  55.2    +2.2
+  Mola de Formentera   38  39.9    -1.2
+  Tetica               37  15.2    +3.5
+  Roldan               36  56.6    -6.0
+  Conjuros             36  44.4   -12.6
+  Mt. Sabiha           35  39.6    +6.5
+  Nemours              35   5.8    +7.4
+  Bouzareah            36  48.0    +2.9
+  Algiers (Voirol)     36  45.1    -9.1
+  Guelt es Stel        35   7.8    -1.0
+  El Aghuat            33  48.0    -2.8
+
+[Illustration]
+
+While the radius of curvature of this arc is obviously not uniform
+(being, in the mean, about 600 metres greater in the northern than in
+the southern part), the Russo-Scandinavian meridian arc (from 45 deg. to
+70 deg.), on the other hand, is very uniformly curved, and gives, with an
+ellipticity of 1/299.15, a = 6378455 metres; this arc gives the
+plausible value 1/298.6 for the ellipticity. But in the case of this arc
+the orographical circumstances are more favourable.
+
+The west-European and the Russo-Scandinavian meridians indicate another
+anomaly of the geoid. They were connected at the Central Bureau by means
+of east-to-west triangle chains (principally by the arc of parallel
+measurements in lat. 52 deg.); it was shown that, if one proceeds from the
+west-European meridian arcs, the differences between the astronomical
+and geodetic latitudes of the Russo-Scandinavian arc become some 4"
+greater.[13]
+
+The central European meridian, which passes through Germany and the
+countries adjacent on the north and south, is under review at Potsdam
+(see the publications of the Kgl. Preuss. Geod. Inst., _Lotabweichungen_,
+Nos. 1-3). Particular notice must be made of the Vienna meridian, now
+carried southwards to Malta. The Italian triangulation is now complete,
+and has been joined with the neighbouring countries on the north, and
+with Tunis on the south.
+
+The United States Coast and Geodetic Survey has published an account of
+the transcontinental triangulation and measurement of an arc of the
+parallel of 39 deg., which extends from Cape May (New Jersey), on the
+Atlantic coast, to Point Arena (California), on the Pacific coast, and
+embraces 48 deg. 46' of longitude, with a linear development of about 4225
+km. (2625 miles). The triangulation depends upon ten base-lines, with an
+aggregate length of 86 km. the longest exceeding 17 km. in length, which
+have been measured with the utmost care. In crossing the Rocky
+Mountains, many of its sides exceed 100 miles in length, and there is
+one side reaching to a length of 294 km., or 183 miles; the altitude of
+many of the stations is also considerable, reaching to 4300 metres, or
+14,108 ft., in the case of Pike's Peak, and to 14,421 ft. at Elbert
+Peak, Colo. All geometrical conditions subsisting in the triangulation
+are satisfied by adjustment, inclusive of the required accord of the
+base-lines, so that the same length for any given line is found, no
+matter from what line one may start.[14]
+
+Over or near the arc were distributed 109 latitude stations, occupied
+with zenith telescopes; 73 azimuth stations; and 29 telegraphically
+determined longitudes. It has thus been possible to study in a very
+complete manner the deviations of the vertical, which in the mountainous
+regions sometimes amount to 25 seconds, and even to 29 seconds.
+
+With the ellipticity 1/299.15, a = 6377897 +- 65 metres (prob. error); in
+this calculation, however, some exceedingly perturbed stations are
+excluded; for the employed stations the mean perturbation in longitude
+is +- 4.9" (zenith-deflection east-to-west +- 3.8").
+
+The computations relative to another arc, the "eastern oblique arc of
+the United States," are also finished.[15] It extends from Calais
+(Maine) in the north-east, to the Gulf of Mexico, and terminates at New
+Orleans (Louisiana), in the south. Its length is 2612 km. (1623 miles),
+the difference of latitude 15 deg. 1', and of longitude 22 deg. 47'. In the
+main, the triangulation follows the Appalachian chain of mountains,
+bifurcating once, so as to leave an oval space between the two branches.
+It includes among its stations Mount Washington (1920 metres) and Mount
+Mitchell (2038 metres). It depends upon six base-lines, and the
+adjustment is effected in the same manner as for the arc of the
+parallel. The astronomical data have been afforded by 71 latitude
+stations, 17 longitude stations, and 56 azimuth stations, distributed
+over the whole extent of the arc. The resulting dimensions of an
+osculating spheroid were found to be
+
+  a = 6378157 metres +- 90 (prob. error),
+  e(ellipticity) = 1/304.5 +- 1.9 (prob. error).
+
+With the ellipticity 1/399.15, a = 6378041 metres +- 80 (prob. er.).
+
+During the years 1903-1906 the United States Coast and Geodetic Survey,
+under the direction of O.H. Tittmann and the special management of John
+F. Hayford, executed a calculation of the best ellipsoid of rotation for
+the United States. There were 507 astronomical determinations employed,
+all the stations being connected through the net-work of triangles. The
+observed latitudes, longitude and azimuths were improved by the
+attractions of the earth's crust on the hypothesis of isostasis for
+three depths of the surface of 114, 121 and 162 km., where the isostasis
+is complete. The land-masses, within the distance of 4126 km., were
+taken into consideration. In the derivation of an ellipsoid of rotation,
+the first case proved itself the most favourable, and there resulted:--
+
+  a = 6378283 metres +- 74 (prob. er.), ellipticity
+    = 1/297.8 +- 0.9 (prob. er.).
+
+The most favourable value for the depth of the isostatic surface is
+approximately 114 km.
+
+The measurement of a great meridian arc, in long. 98 deg. W., has been
+commenced; it has a range of latitude of 23 deg., and will extend over 50 deg.
+when produced southwards and northwards by Mexico and Canada. It may
+afterwards be connected with the arc of Quito. A new measurement of the
+meridian arc of Quito was executed in the years 1901-1906 by the
+_Service geographique_ of France under the direction of the Academie des
+Sciences, the ground having been previously reconnoitred in 1899. The
+new arc has an amplitude in latitude of 5 deg. 53' 33", and stretches from
+Tulcan (lat. 0 deg. 48' 25") on the borders of Columbia and Ecuador, through
+Columbia to Payta (lat. -5 deg. 5' 8") in Peru. The end-points, at which the
+chain of triangles has a slight north-easterly trend, show a longitude
+difference of 3 deg.. Of the 74 triangle points, 64 were latitude stations;
+6 azimuths and 8 longitude-differences were measured, three base-lines
+were laid down, and gravity was determined from six points, in order to
+maintain indications over the general deformation of the geoid in that
+region. Computations of the attraction of the mountains on the
+plumb-line are also being considered. The work has been much delayed by
+the hardships and difficulties encountered. It was conducted by
+Lieut.-Colonel Robert Bourgeois, assisted by eleven officers and
+twenty-four soldiers of the geodetic branch of the _Service
+geographique_. Of these officers mention may be made of Commandant E.
+Maurain, who retired in 1904 after suffering great hardships; Commandant
+L. Massenet, who died in 1905; and Captains I. Lacombe, A. Lallemand,
+and Lieut. Georges Perrier (son of General Perrier). It is conceivable
+that the chain of triangles in longitude 98 deg. in North America may be
+united with that of Ecuador and Peru: a continuous chain over the whole
+of America is certainly but a question of time. During the years
+1899-1902 the measurement of an arc of meridian was made in the extreme
+north, in Spitzbergen, between the latitudes 76 deg. 38' and 80 deg. 50',
+according to the project of P.G. Rosen. The southern part was determined
+by the Russians--O. Baecklund, Captain D.D. Sergieffsky, F.N.
+Tschernychev, A. Hansky and others--during 1899-1901, with the aid of 1
+base-line, 15 trigonometrical, 11 latitude and 5 gravity stations. The
+northern part, which has one side in common with the southern part, has
+been determined by Swedes (Professors Rosen, father and son, E. Jaederin,
+T. Rubin and others), who utilized 1 base-line, 9 azimuth measurements,
+18 trigonometrical, 17 latitude and 5 gravity stations. The party worked
+under excessive difficulties, which were accentuated by the arctic
+climate. Consequently, in the first year, little headway was made.[16]
+
+Sir David Gill, when director of the Royal Observatory, Cape Town,
+instituted the magnificent project of working a latitude-degree
+measurement along the meridian of 30 deg. long. This meridian passes through
+Natal, the Transvaal, by Lake Tanganyika, and from thence to Cairo;
+connexion with the Russo-Scandinavian meridian arc of the same longitude
+should be made through Asia Minor, Turkey, Bulgaria and Rumania. With
+the completion of this project a continuous arc of 105 deg. in latitude will
+have been measured.[17]
+
+Extensive triangle chains, suitable for latitude-degree measurements,
+have also been effected in Japan and Australia.
+
+Besides, the systematization of gravity measurements is of importance,
+and for this purpose the association has instituted many reforms. It has
+ensured that the relative measurements made at the stations in different
+countries should be reduced conformably with the absolute determinations
+made at Potsdam; the result was that, in 1906, the intensities of
+gravitation at some 2000 stations had been co-ordinated. The intensity
+of gravity on the sea has been determined by the comparison of
+barometric and hypsometric observations (Mohn's method). The
+association, at the proposal of Helmert, provided the necessary funds
+for two expeditions:--English Channel--Rio de Janeiro, and the Red
+Sea--Australia--San Francisco--Japan. Dr O. Hecker of the central bureau
+was in charge; he successfully overcame the difficulties of the work,
+and established the tenability of the isostatic hypothesis, which
+necessitates that the intensity of gravity on the deep seas has, in
+general, the same value as on the continents (without regard to the
+proximity of coasts).[18]
+
+As the result of the more recent determinations, the ellipticity,
+compression or flattening of the ellipsoid of the earth may be assumed
+to be very nearly 1/298.3; a value determined in 1901 by Helmert from
+the measurements of gravity. The semi-major axis, a, of the meridian
+ellipse may exceed 6,378,000 inter. metres by about 200 metres. The
+central bureau have adopted, for practical reasons, the value 1/299.15,
+after Bessel, for which tables exist; and also the value a =
+6377397.155(1 + 0.0001).
+
+The methods of theoretical astronomy also permit the evaluation of these
+constants. The semi-axis a is calculable from the parallax of the moon
+and the acceleration of gravity on the earth; but the results are
+somewhat uncertain: the ellipticity deduced from lunar perturbations is
+1/297.8 +- 2 (Helmert, _Geodaesie_, ii. pp. 460-473); William Harkness
+(_The Solar Parallax and its related Constants_, 1891) from all possible
+data derived the values: ellipticity = 1/300.2 +- 3, a = 6377972 +- 125
+metres. Harkness also considered in this investigation the relation of
+the ellipticity to precession and nutation; newer investigations of the
+latter lead to the limiting values 1/296, 1/298 (Wiechert). It was
+clearly noticed in this method of determination that the influence of
+the assumption as to the density of the strata in the interior of the
+earth was but very slight (Radau, _Bull. astr._ ii. (1885) 157). The
+deviations of the geoid from the flattened ellipsoid of rotation with
+regard to the heights (the directions of normals being nearly the same)
+will scarcely exceed +- 100 metres (Helmert).[19]
+
+The basis of the degree- and gravity-measurements is actually formed by
+a stationary sea-surface, which is assumed to be level. However, by the
+influence of winds and ocean currents the mean surface of the sea near
+the coasts (which one assumes as the fundamental sea-surface) can
+deviate somewhat from a level surface. According to the more recent
+levelling it varies at the most by only some decimeters.[20]
+
+It is well known that the masses of the earth are continually undergoing
+small changes; the earth's crust and sea-surface reciprocally oscillate,
+and the axis of rotation vibrates relatively to the body of the earth.
+The investigation of these problems falls in the programme of the
+Association. By continued observations of the water-level on sea-coasts,
+results have already been obtained as to the relative motions of the
+land and sea (cf. GEOLOGY); more exact levelling will, in the course of
+time, provide observations on countries remote from the sea-coast. Since
+1900 an international service has been organized between some
+astronomical stations distributed over the north parallel of 39 deg. 8', at
+which geographical latitudes are observed whenever possible. The
+association contributes to all these stations, supporting four entirely:
+two in America, one in Italy, and one in Japan; the others partially
+(Tschardjui in Russia, and Cincinnati observatory). Some observatories,
+especially Pulkowa, Leiden and Tokyo, take part voluntarily. Since 1906
+another station for South America and one for Australia in latitude -31 deg.
+55' have been added. According to the existing data, geographical
+latitudes exhibit variations amounting to +-0.25", which, for the greater
+part, proceed from a twelve- and a fourteen-month period.[21]
+     (A. R. C; F. R. H.)
+
+
+FOOTNOTES:
+
+  [1] _Eratosthenes Batavus, seu de terrae ambitus vera quantitate
+    suscitatus, a Willebrordo Snellio, Lugduni-Batavorum_ (1617).
+
+  [2] O. Callandreau, "Memoire sur la theorie de la figure des
+    planetes," _Ann. obs. de Paris_ (1889); G.H. Darwin, "The Theory of
+    the Figure of the Earth carried to the Second Order of Small
+    Quantities," _Mon. Not. R.A.S._, 1899; E. Wiechert, "Ueber die
+    Massenverteilung im Innern der Erde," _Nach. d. koen. G. d. W. zu
+    Goett._, 1897.
+
+  [3] See I. Todhunter, _Proc. Roy. Soc._, 1870.
+
+  [4] J.H. Jeans, "On the Vibrations and Stability of a Gravitating
+    Planet," _Proc. Roy. Soc._ vol. 71; G.H. Darwin, "On the Figure and
+    Stability of a liquid Satellite," _Phil. Trans._ 206, p. 161; A.E.H.
+    Love, "The Gravitational Stability of the Earth," _Phil. Trans._ 207,
+    p. 237; _Proc. Roy. Soc._ vol. 80.
+
+  [5] _Survey of India_, "The Attraction of the Himalaya Mountains upon
+    the Plumb Line in India" (1901), p. 98.
+
+  [6] _Account of Experiments to Determine the Figure of the Earth by
+    means of a Pendulum vibrating Seconds in Different Latitudes_ (1825).
+
+  [7] Helmert, _Theorien d. hoeheren Geod._ ii., Leipzig, 1884.
+
+  [8] Helmert, _Sitzber. d. kgl. preuss. Ak. d. Wiss. zu Berlin_
+    (1901), p. 336.
+
+  [9] "Bestimmung der absoluten Groesse der Schwerkraft zu Potsdam mit
+    Reversionspendeln" (_Veroeffentlichung des kgl. preuss. Geod. Inst._,
+    N.F., No. 27).
+
+  [10] _Die Koenigl. Observatorien fuer Astrophysik, Meteorologie und
+    Geodaesie bei Potsdam_ (Berlin, 1890); _Verhandlungen der I.
+    Allgemeinen Conferenz der Bevollmaechtigten zur mitteleurop.
+    Gradmessung_, October, 1864, in Berlin (Berlin, 1865); A. Hirsch,
+    _Verhandlungen der VIII. Allg. Conf. der Internationalen Erdmessung_,
+    October, 1886, in Berlin (Berlin, 1887); and _Verhandlungen der XI.
+    Allg. Conf. d. I. E._, October, 1895, in Berlin (1896).
+
+  [11] Ibanez and Perrier, _Jonction geod. et astr. de l'Algerie avec
+    l'Espagne_ (Paris, 1886); _Memorial du depot general de la guerre_,
+    t. xii.: _Nouvelle meridienne de France_ (Paris, 1885, 1902, 1904);
+    _Comptes rendus des seances de la 12^e-19^e conference generale de
+    l'Assoc. Geod. Internat._, 1898 at Stuttgart, 1900 at Paris, 1903 at
+    Copenhagen, 1906 at Budapest (Berlin, 1899, 1901, 1904, 1908); A.
+    Ferrero, _Rapport sur les triangulations, pres. a la 12^e conf. gen.
+    1898_.
+
+  [12] R. Schumann, _C. r. de Budapest_, p. 244.
+
+  [13] O. and A. Boersch, "Verbindung d. russ.-skandinav. mit der
+    franz.-engl. Breitengradmessung" (_Verhandlungen der 9. Allgem. Conf.
+    d. I. E. in Paris, 1889_, Ann. xi.).
+
+  [14] U.S. Coast and Geodetic Survey; H.S. Pritchett, superintendent.
+    _The Transcontinental Triangulation and the American Arc of the
+    Parallel_, by C.A. Schott (Washington, 1900).
+
+  [15] U.S. Coast and Geodetic Survey; O.H. Tittmann, superintendent.
+    _The Eastern Oblique Arc of the United States_, by C.A. Schott
+    (1902).
+
+  [16] _Missions scientifiques pour la mesure d'un arc de meridien au
+    Spitzberg entreprises en 1899-1902 sous les auspices des
+    gouvernements russe et suedois._ _Mission russe_ (St Petersbourg,
+    1904); _Mission suedoise_ (Stockholm, 1904).
+
+  [17] Sir David Gill, _Report on the Geodetic Survey of South Africa,
+    1833-1892_ (Cape Town, 1896), vol. ii. 1901, vol. iii. 1905.
+
+  [18] O. Hecker, _Bestimmung der Schwerkraft a. d. Atlantischen Ozean_
+    (Veroeffentl. d. Kgl. Preuss. Geod. Inst. No. 11), Berlin, 1903.
+
+  [19] F.R. Helmert. "Neuere Fortschritte in der Erkenntnis der math.
+    Erdgestalt" (_Verhandl. des VII. Internationalen
+    Geographen-Kongresses, Berlin, 1899_), London, 1901.
+
+  [20] C. Lallemand, "Rapport sur les travaux du service du nivellement
+    general de la France, de 1900 a 1906" (_Comp. rend. de la 14^e conf.
+    gen. de l'Assoc. Geod-Intern., 1903_, p. 178).
+
+  [21] T. Albrecht, _Resultate des internat. Breitendienstes_, i. and
+    ii. (Berlin, 1903 and 1906); F. Klein and A. Sommerfeld, _Ueber die
+    Theorie des Kreisels_, iii. p. 672; R. Spitaler, "Die periodischen
+    Luftmassenverschiebungen und ihr Einfluss auf die Lagenaenderung der
+    Erdaxe" (_Petermanns Mitteilungen, Ergaenzungsheft_, 137); S. Newcomb,
+    "Statement of the Theoretical Laws of the Polar Motion"
+    (_Astronomical Journal_, 1898, xix. 158); F.R. Helmert, "Zur
+    Erklaerung der beobachteten Breitenaenderungen" (_Astr. Nachr._ No.
+    3014); J. Weeder, "The 14-monthly period of the motion of the Pole
+    from determinations of the azimuth of the meridian marks of the
+    Leiden observatory" (_Kon. Ak. van Wetenschappen to Amsterdam_,
+    1900); A. Sokolof, "Determination du mouvement du pole terr. au moyen
+    des mires meridiennes de Poulkovo" (_Mel. math. et astr._ vii.,
+    1894); J. Bonsdorff, "Beobachtungen von [delta] Cassiopejae mit dem
+    grossen Zenitteleskop" (_Mitteilungen der Nikolai-Hauptsternwarte zu
+    Pulkowo_, 1907); J. Larmor and E.H. Hills, "The irregular movement of
+    the Earth's axis of rotation: a contribution towards the analysis of
+    its causes" (_Monthly Notices R.A.S._, 1906, lxvii. 22); A.S.
+    Cristie, "The latitude variation Tide" (_Phil. Soc. of Wash._, 1895,
+    _Bull._ xiii. 103); H.G. van de Sande Bakhuysen, "Ueber die Aenderung
+    der Polhoehe" (_Astr. Nachr._ No. 3261); A.V. Baecklund, "Zur Frage
+    nach der Bewegung des Erdpoles" (_Astr. Nachr._ No. 3787); R.
+    Schumann, "Ueber die Polhoehenschwankung" (_Astr. Nachr._ No. 3873);
+    "Numerische Untersuchung" (_Ergaenzungshefte zu den Astr. Nachr._ No.
+    11); _Weitere Untersuchungen_ (No. 4142); _Bull. astr._, 1900, June,
+    report of different theoretical memoirs.
+
+
+
+
+EARTH CURRENTS. After the invention of telegraphy it was soon found that
+telegraph lines in which the circuit is completed by the earth are
+traversed by natural electric currents which occasionally interfere
+seriously with their use, and which are known as "earth currents."
+
+1. Amongst the pioneers in investigating the subject were several English
+telegraphists, e.g. W.H. Barlow (1) and C.V. Walker (2), who were in
+charge respectively of the Midland and South-Eastern telegraph systems.
+Barlow noticed the existence of a more or less regular diurnal variation,
+and the result--confirmed by all subsequent investigators--that earth
+currents proper occur in a line only when both ends are earthed. Walker,
+as the result of general instructions issued to telegraph clerks,
+collected numerous statistics as to the phenomena during times of large
+earth currents. His results and those given by Barlow both indicate that
+the lines to suffer most from earth currents in England have the general
+direction N.E. to S.W. As Walker points out, it is the direction of the
+terminal plates relative to one another that is the essential thing. At
+the same time he noticed that whilst at any given instant the currents in
+parallel lines have with rare exceptions the same direction, some lines
+show normally stronger currents than others, and he suggested that
+differences in the geological structure of the intervening ground might
+be of importance. This is a point which seems still somewhat obscure.
+
+Our present knowledge of the subject owes much to practical men, but
+even in the early days of telegraphy the fact that telegraph systems are
+commercial undertakings, and cannot allow the public to wait the
+convenience of science, was a serious obstacle to their employment for
+research. Thus Walker feelingly says, when regretting his paucity of
+data during a notable earth current disturbance: "Our clerks were at
+their wits' end to clear off the telegrams.... At a time when
+observations would have been very highly acceptable they were too much
+occupied with their ordinary duties." Some valuable observations have,
+however, been made on long telegraph lines where special facilities have
+been given.
+
+Amongst these may be mentioned the observations on French lines in 1883
+described by E.E. Blavier (3), and those on two German lines
+Berlin-Thorn and Berlin-Dresden during 1884 to 1888 discussed by B.
+Weinstein (4).
+
+2. Of the experimental lines specially constructed perhaps the best
+known are the Greenwich lines instituted by Sir G.B. Airy (5), the lines
+at Pawlowsk due to H. Wild (6), and those at Parc Saint Maur, near Paris
+(7).
+
+_Experimental Lines._--At Greenwich observations were commenced in 1865,
+but there have been serious disturbances due to artificial currents from
+electric railways for many years. There are two lines, one to Dartford
+distant about 10 m., in a direction somewhat south of east, the other to
+Croydon distant about 8 m., in a direction west of south.
+
+Information from a single line is incomplete, and unless this is clearly
+understood erroneous ideas may be derived. The times at which the
+current is largest and least, or when it vanishes, in an east-west line,
+tell nothing directly as to the amplitude at the time of the resultant
+current. The lines laid down at Pawlowsk in 1883 lay nearly in and
+perpendicular to the geographical meridian, a distinct desideratum, but
+were only about 1 km. long. The installation at Parc Saint Maur,
+discussed by T. Moureaux, calls for fuller description. There are three
+lines, one having terminal earth plates 14.8 km. apart in the
+geographical meridian, a second having its earth plates due east and
+west of one another, also 14.8 km. apart, and the third forming a closed
+circuit wholly insulated from the ground. In each of the three lines is
+a Deprez d'Arsonval galvanometer. Light reflected from the galvanometer
+mirrors falls on photographic paper wound round a drum turned by
+clockwork, and a continuous record is thus obtained.
+
+3. Each galvanometer has a resistance of about 200 ohms, but is shunted
+by a resistance of only 2 ohms. The total effective resistances in the
+N.-S. and E.-W. lines are 225 and 348 ohms respectively. If i is the
+current recorded, L, g and s the resistances of the line, galvanometer
+and shunt respectively, then E, the difference of potential between the
+two earth plates, is given by
+
+  E = i(1 + g/s) {L + gs/(g + s)}.
+
+To calibrate the record, a Daniell cell is put in a circuit including
+1000 ohms and the three galvanometers as shunted. If i' be the current
+recorded, e the E.M.F. of the cell, then e = i'(1 + g/s){1000 + 3gs/(g +
+s)}. Under the conditions at Parc Saint Maur we may write 2 for gs/(g +
+s), and 1.072 for e, and thence we have approximately E = 0.240(i/i')
+for the N.-S. line, and E = -0.371(i/i') for the E.-W. line.
+
+The method of standardization assumes a potential difference between
+earth plates which varies slowly enough to produce a practically steady
+current. There are several causes producing currents in a telegraph wire
+which do not satisfy this limitation. During thunderstorms surgings may
+arise, at least in overhead wires, without these being actually struck.
+Again, if the circuit includes a variable magnetic field, electric
+currents will be produced independently of any direct source of
+potential difference. In the third circuit at Parc Saint Maur, where no
+earth plates exist, the current must be mainly due to changes in the
+earth's vertical magnetic field, with superposed disturbances due to
+atmospheric electricity or aerial waves. Even in the other circuits,
+magnetic and atmospheric influences play some part, and when their
+contribution is important, the galvanometer deflection has an uncertain
+value. What a galvanometer records when traversed by a suddenly varying
+current depends on other things than its mere resistance.
+
+Even when the current is fairly steady, its exact significance is not
+easily stated. In the first place there is usually an appreciable E.M.F.
+between a plate and the earth in contact with it, and this E.M.F. may
+vary with the temperature and the dryness of the soil. Naturally one
+employs similar plates buried to the same depth at the two ends, but
+absolute identity and invariability of conditions can hardly be secured.
+In some cases, in short lines (8), there is reason to fear that plate
+E.M.F.'s have been responsible for a good deal that has been ascribed to
+true earth currents. With deep earth plates, in dry ground, this source
+of uncertainty can, however, enter but little into the diurnal
+inequality.
+
+4. Another difficulty is the question of the resistance in the earth
+itself. A given E.M.F. between plates 10 m. apart may mean very
+different currents travelling through the earth, according to the
+chemical constitution and condition of the surface strata.
+
+According to Professor A. Schuster (9), if [rho] and [rho]' be the
+specific resistances of the material of the wire and of the soil, the
+current i which would pass along an underground cable formed of actual
+soil, equal in diameter to the wire connecting the plates, is given by i
+= i'[rho]/[rho]', where i' is the observed current in the wire. As
+[rho]' will vary with the depth, and be different at different places
+along the route, while discontinuities may arise from geological faults,
+water channels and so on, it is clear that even the most careful
+observations convey but a general idea as to the absolute intensity of
+the currents in the earth itself. In Schuster's formula, as in the
+formulae deduced for Parc Saint Maur, it is regarded as immaterial
+whether the wire connecting the plates is above or below ground. This
+view is in accordance with records obtained by Blavier (3) from two
+lines between Paris and Nancy, the one an air line, the other
+underground.
+
+5. The earliest quantitative results for the regular diurnal changes in
+earth currents are probably those deduced by Airy (5) from the records
+at Greenwich between 1865 and 1867. Airy resolved the observed currents
+from the two Greenwich lines in and perpendicular to the _magnetic_
+meridian (then about 21 deg. to the west of astronomical north). The
+information given by Airy as to the precise meaning of the quantities he
+terms "magnetic tendency" to north and to west is somewhat scanty, but
+we are unlikely to be much wrong in accepting his figures as
+proportional to the earth currents from magnetic east to west and from
+magnetic north to south respectively. Airy gives mean hourly values for
+each month of the year. The corresponding mean diurnal inequality for
+the whole year appears in Table 1., the unit being arbitrary. In every
+month the algebraic mean of the 24 hourly values represented a current
+from north to south in the magnetic meridian, and from east to west in
+the perpendicular direction; in the same arbitrary units used in Table
+I. the mean values of these two "constant" currents were respectively
+777 and 559.
+
+6. _Diurnal Variation._--Probably the most complete records of diurnal
+variation are those discussed by Weinstein (4), which depend on several
+years' records on lines from Berlin to Dresden and to Thorn. Relative to
+Berlin the geographical co-ordinates of the other two places are:
+
+  Thorn       0 deg. 29' N. lat. 5 deg. 12' E. long.
+  Dresden     1 deg. 28' S. lat. 0 deg. 21' E. long.
+
+Thus the Berlin-Dresden line was directed about 81/2 deg. east of south, and
+the Berlin-Thorn line somewhat more to the north of east. The latter
+line had a length about 2.18 times that of the former. The resistances
+in the two lines were made the same, so if we suppose the difference of
+potential between earth plates along a given direction to vary as their
+distance apart, the current observed in the Thorn-Berlin line has to be
+divided by 2.18 to be comparable with the other. In this way, resolving
+along and perpendicular to the geographical meridian, Weinstein gives as
+proportional to the earth currents from east to west and from south to
+north respectively
+
+  J = 0.147i' + 0.435i, and J' = 0.989i' - 0.100i,
+
+where i and i' are the observed currents in the Thorn-Berlin and
+Dresden-Berlin lines respectively, both being counted positive when
+flowing towards Berlin.
+
+It is tacitly assumed that the average earth conductivity is the same
+between Berlin and Thorn as between Berlin and Dresden. It should also
+be noticed that local time at Berlin and Thorn differs by fully 20
+minutes, while the crests of the diurnal variations in _short_ lines at
+the two places would probably occur about the same local time. The
+result is probably a less sharp occurrence of maxima and minima, and a
+relatively smaller range, than in a short line having the same
+orientation.
+
+  TABLE I.
+
+  +-----------------------------------------------------+------------------------------+
+  |       Mean Diurnal Inequalities for the year.       |Numerical Values of resultant |
+  |                                                     |           current.           |
+  +----------------------+------------------------------+------------------------------+
+  |      Greenwich.      |     Thorn-Berlin-Dresden.    |    Thorn-Berlin-Dresden.     |
+  +--------+-------------+--------+-------+------+------+------------------------------+
+  |        |North | East | Berlin | Thorn |North | East |   Mean hourly values from    |
+  |  Hour. |  to  |  to  |   to   |  to   |  to  |  to  +-----+-------+--------+-------+
+  |        |South | West |Dresden.|Berlin.|South | West |Year.|Winter.|Equinox.|Summer.|
+  |        |(Mag.)|(Mag.)|        |       |(Ast.)|(Ast.)|     |       |        |       |
+  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
+  |    1   |  -94 |  -41 |   -17  |  -13  |  -20 |  -10 |  81 |   94  |    51  |   98  |
+  |    2   |  -68 |  -24 |    -6  |  -13  |   -9 |  -11 |  84 |  115  |    39  |   97  |
+  |    3   |  -44 |   -8 |    -1  |   -1  |   -1 |   -1 |  84 |  113  |    31  |  108  |
+  |    4   |  -18 |   +9 |   -20  |  +15  |  -17 |  +17 | 101 |   94  |    58  |  127  |
+  |    5   |  -30 |   -1 |   -79  |  +21  |  -74 |  +32 | 122 |   58  |    78  |  230  |
+  |    6   |  -63 |  -33 |  -139  |   +5  | -136 |  +26 | 148 |   80  |   139  |  225  |
+  |    7   | -121 |  -80 |  -138  |  -36  | -144 |  -14 | 166 |  155  |   206  |  136  |
+  |    8   | -175 | -123 |    -7  |  -98  |  -28 |  -92 | 203 |  152  |   185  |  271  |
+  |    9   | -156 | -137 |  +249  | -156  | +212 | -184 | 305 |   67  |   272  |  575  |
+  |   10   |  -43 |  -77 |  +540  | -184  | +494 | -254 | 557 |  232  |   628  |  811  |
+  |   11   |  +82 |   +1 |  +722  | -165  | +678 | -263 | 728 |  411  |   885  |  887  |
+  |  Noon  | +207 |  +66 |  +673  | -107  | +642 | -200 | 675 |  441  |   848  |  735  |
+  |    1   | +245 |  +94 |  +404  |  -20  | +395 |  -79 | 400 |  284  |   510  |  406  |
+  |    2   | +205 | +113 |   +35  |  +55  |  +46 |  +47 |  98 |   68  |   103  |  125  |
+  |    3   | +153 |  +97 |  -261  |  +99  | -237 | +132 | 272 |  136  |   355  |  324  |
+  |    4   | +159 | +108 |  -397  | +114  | -368 | +167 | 404 |  218  |   503  |  492  |
+  |    5   | +167 | +118 |  -391  | +108  | -363 | +160 | 397 |  206  |   453  |  532  |
+  |    6   | +125 |  +95 |  -311  |  +96  | -287 | +137 | 319 |  176  |   333  |  446  |
+  |    7   |  +43 |  +55 |  -237  |  +85  | -216 | +115 | 247 |  180  |   250  |  312  |
+  |    8   |  -22 |   +4 |  -191  |  +74  | -173 |  +98 | 201 |  207  |   217  |  181  |
+  |    9   | -115 |  -49 |  -168  |  +59  | -153 |  +81 | 174 |  208  |   194  |  120  |
+  |   10   | -138 |  -74 |  -135  |  +40  | -125 |  +58 | 138 |  155  |   149  |  111  |
+  |   11   | -136 |  -70 |   -84  |  +18  |  -79 |  +29 |  89 |   64  |    95  |  107  |
+  |Midnight| -147 |  -80 |   -43  |   -2  |  -43 |   +4 |  91 |   42  |   119  |  111  |
+  +--------+------+------+--------+-------+------+------+-----+-------+--------+-------+
+
+It was found that the average current derived from a number of
+undisturbed days on either line might be regarded as made up of a
+"constant part" plus a regular diurnal inequality, the constant part
+representing the algebraic mean value of the 24 hourly readings. In both
+lines the constant part showed a decided alteration during the third
+year--changing sign in one line--in consequence, it is believed, of
+alterations made in the earth plates. The constant part was regarded as
+a plate effect, and was omitted from further consideration. Table I.
+shows in terms of an arbitrary unit--whose relation to that employed for
+Greenwich data is unknown--the diurnal inequality in the currents along
+the two lines, and the inequalities thence calculated for ideal lines in
+and perpendicular to the _geographical_ meridian. Currents are regarded
+as positive when directed from Berlin to Dresden and from north to
+south, the opposite point of view to that adopted by Weinstein. The
+table also shows the mean _numerical_ value of the resultant current
+(the "constant" part being omitted) for each hour of the day, for the
+year as a whole, and for winter (November to February), equinox (March,
+April, September, October) and summer (May to August). There is a marked
+double period in both the N.-S. and E.-W. currents. In both cases the
+numerically largest currents occur from 10 A.M. to noon, the directions
+then being from north to south and from west to east. The currents tend
+to die out and change sign about 2 P.M., the numerical magnitude then
+rising again rapidly to 4 or 5 P.M. The current in the meridian is
+notably the larger. The numerical values assigned to the resultant
+current are arithmetic means from the several months composing the
+season in question.
+
+7. The mean of the 24 hourly numerical values of the resultant current
+for each month of the year a deducible from Weinstein's data--the unit
+being the same as before--are given in Table II.
+
+  TABLE II.--_Mean Numerical Value of Resultant Current._
+
+  Jan.  Feb.  March  April  May  June  July  Aug.  Sep.  Oct.  Nov.  Dec.
+  152   211    293    328   313   314   337  300   258   235   165   132
+
+There is thus a conspicuous minimum at mid-winter, and but little
+difference between the monthly means from April to August. This is
+closely analogous to what is seen in the daily range of the magnetic
+elements in similar latitudes (see MAGNETISM, TERRESTRIAL). There is
+also considerable resemblance between the curve whose ordinates
+represent the diurnal inequality in the current passing from north to
+south, and the curve showing the hourly change in the westerly component
+of the horizontal magnetic force in similar European latitudes.
+
+8. _Relations with Sun-spots, Auroras and Magnetic Storms._--Weinstein
+gives curves representing the mean diurnal inequality for separate
+years. In both lines the diurnal amplitudes were notably smaller in the
+later years which were near sun-spot minimum. This raises a presumption
+that the regular diurnal earth currents, like the ranges of the magnetic
+elements, follow the 11-year sun-spot period. When we pass to the large
+and irregular earth currents, which are of practical interest in
+telegraphy, there is every reason to suppose that the sun-spot period
+applies. These currents are always accompanied by magnetic disturbances,
+and when specially striking by brilliant aurora. One most conspicuous
+example of this occurred in the end of August and beginning of September
+1859. The magnetic disturbances recorded were of almost unexampled size
+and rapidity, the accompanying aurora was extraordinarily brilliant, and
+E.M.F.'s of 700 and 800 volts are said to have been reached on telegraph
+lines 500 to 600 km. long. It is doubtful whether the disturbances of
+1859 have been equalled since, but earth current voltages of the order
+of 0.5 volts per mile have been recorded by various authorities, e.g.
+Sir W.H. Preece (10).
+
+It was the practice for several years to publish in the _Ann. du bureau
+central meteorologique_ synchronous magnetic and earth current curves
+from Parc Saint Maur corresponding to the chief disturbances of the
+year. In most cases there is a marked similarity between the curve of
+magnetic declination and that of the north-south earth current. At times
+there is also a distinct resemblance between the horizontal force
+magnetic curve and that of the east-west earth current, but exceptions
+to this are not infrequent. Similar phenomena appear in synchronous
+Greenwich records published by Airy in 1868; these show a close
+accordance between the horizontal force curves and those of the currents
+from magnetic east to west. Originally it was supposed by Airy that
+whilst rapid movements in the declination and north-south current curves
+sometimes occurred simultaneously, there was a distinct tendency for
+the latter to precede the former. More recent examinations of the
+Greenwich records by W. Ellis (11), and of the Parc St Maur curves by
+Moureaux, have not confirmed this result, and it is now believed that
+the two phenomena are practically simultaneous.
+
+There has also been a conflict of views as to the connexion between
+magnetic and earth current disturbances. Airy's observations tended to
+suggest that the earth current was the primary cause, and the magnetic
+disturbance in considerable part at least its effect. Others, on the
+contrary, have supposed earth currents to be a direct effect of changes
+in the earth's magnetic field. The prevailing view now is that both the
+magnetic and the earth current disturbances are due to electric currents
+in the upper atmosphere, these upper currents becoming visible at times
+as aurora.
+
+9. There seems some evidence that earth currents can be called into
+existence by purely local causes, notably difference of level. Thus K.A.
+Brander (12) has observed a current flowing constantly for a good many
+days from Airolo (height 1160 metres) to the Hospice St Gotthard (height
+2094 metres). In an 8-km. line from Resina to the top of Vesuvius L.
+Palmieri (13)--observing in 1889 at three-hour intervals from 9 A.M. to
+9 P.M.--always found a current running uphill so long as the mountain
+was quiet. On a long line from Vienna to Graz A. Baumgartner (14) found
+that the current generally flowed from both ends towards intervening
+higher ground during the day, but in the opposite directions at night.
+During a fortnight in September and October 1885 hourly readings were
+taken of the current in the telegraph cable from Fort-William to Ben
+Nevis Observatory, and the results were discussed by H.N. Dickson (15),
+who found a marked preponderance of currents up the line to the summit.
+The recorded mean data, otherwise regarded, represent a "constant"
+current, equal to 29 in the arbitrary units employed by Dickson, flowing
+up the line, together with the following diurnal inequality, + denoting
+current towards Fort-William (i.e. down the hill, and nearly east to
+west).
+
+  Hour |  1  |  2  |  3  |  4  |  5  | 6  |  7  |  8  |   9 |  10 |  11 |  12 |
+       |     |     |     |     |     |    |     |     |     |     |     |     |
+  A.M. | -21 | -41 | +13 | +23 | +55 | -3 | +25 | -32 | -59 | -62 | -46 |  +6 |
+  P.M. | +24 | +18 |+115 | +18 | +75 | -5 | +50 |  -9 | -56 | -37 | -28 | -34 |
+
+There is thus a diurnal inequality, which is by no means very irregular
+considering the limited number of days, and it bears at least a general
+resemblance to that shown by Weinstein's figures for an east-west line
+in Germany. This will serve to illustrate the uncertainties affecting
+these and analogous observations. A constant current in one direction
+may arise in whole or part from plate E.M.F.'s; a current showing a
+diurnal inequality will naturally arise between _any_ two places some
+distance apart whether they be at different levels or not. Finally, when
+records are taken only for a short time, doubts must arise as to the
+generality of the results. During the Ben Nevis observations, for
+instance, we are told that the summit was almost constantly enveloped in
+fog or mist. By having three earth plates in the same vertical plane,
+one at the top of a mountain, the others at opposite sides of it, and
+then observing the currents between the summit and each of the base
+stations, as well as directly between the base stations--during an
+adequate number of days representative of different seasons of the year
+and different climatic conditions--many uncertainties would soon be
+removed.
+
+10. _Artificial Currents._--The great extension in the applications of
+electricity to lighting, traction and power transmission, characteristic
+of the end of the 19th century, has led to the existence of large
+artificial earth currents, which exert a disturbing influence on
+galvanometers and magnetic instruments, and also tend to destroy metal
+pipes. In the former case, whilst the disturbance is generally loosely
+assigned to stray or "vagabond" earth currents, this is only partly
+correct. The currents used for traction are large, and even if there
+were a perfectly insulated return there would be a considerable
+resultant magnetic field at distances from the track which were not
+largely in excess of the distance apart of the direct and return
+currents (16). At a distance of half a mile or more from an electric
+tram line the disturbance is usually largest in magnetographs recording
+the vertical component of the earth's field. The magnets are slightly
+displaced from the position they would occupy if undisturbed, and are
+kept in continuous oscillation whilst the trams are running (17). The
+extent of the oscillation depends on the damping of the magnets.
+
+The distance from an electric tram line where the disturbance ceases to
+be felt varies with the system adopted. It also depends on the length of
+the line and its subdivision into sections, on the strength of the
+currents supplied, the amount of leakage, the absence or presence of
+"boosters," and finally on the sensitiveness of the magnetic
+instruments. At the U.S. Coast and Geodetic Survey's observatory at
+Cheltenham the effect of the Washington electric trams has been detected
+by highly sensitive magnetographs, though the nearest point of the line
+is 12 m. away (18). Amongst the magnetic observatories which have
+suffered severely from this cause are those at Toronto, Washington
+(Naval Observatory), Kew, Paris (Parc St Maur), Perpignan, Nice, Lisbon,
+Vienna, Rome, Bombay (Colaba) and Batavia. In some cases magnetic
+observations have been wholly suspended, in others new observatories
+have been built on more remote sites.
+
+As regards damage to underground pipes, mainly gas and water pipes,
+numerous observations have been made, especially in Germany and the
+United States. When electric tramways have uninsulated returns, and the
+potential of the rails is allowed to differ considerably from that of
+the earth, very considerable currents are found in neighbouring pipes.
+Under these conditions, if the joints between contiguous pipes forming a
+main present appreciable resistance, whilst the surrounding earth
+through moisture or any other cause is a fair conductor, current passes
+locally from the pipes to the earth causing electrolytic corrosion of
+the pipes. Owing to the diversity of interests concerned, the extent of
+the damage thus caused has been very variously estimated. In some
+instances it has been so considerable as to be the alleged cause of the
+ultimate failure of water pipes to stand the pressure they are exposed
+to.
+
+  BIBLIOGRAPHY.--See Svante August Arrhenius, _Lehrbuch der kosmischen
+  Physik_ (Leipzig, 1903), pp. 984-990. For lists of references see J.E.
+  Burbank, _Terrestrial Magnetism_, vol. 10 (1905), p. 23, and P.
+  Bachmetjew (8). For papers descriptive of corrosion of pipes, &c., by
+  artificial currents see _Science Abstracts_ (in recent years in the
+  volumes devoted to engineering) under the heading "Traction, Electric;
+  Electrolysis." The following are the references in the text:--(1)
+  _Phil. Trans. R.S._ for 1849, pt. i. p. 61; (2) _Phil. Trans. R.S._
+  vol. 151 (1861), p. 89, and vol. 152 (1862), p. 203; (3) _Etude des
+  courants telluriques_ (Paris, 1884); (4) _Die Erdstroeme im deutschen
+  Reichstelegraphengebiet_ (Braunschweig, 1900); (5) _Phil. Trans. R.S._
+  vol. 158 (1868), p. 465, and vol. 160 (1870), p. 215; (6) _Mem. de
+  l'Academie St-Petersbourg_, t. 31, No. 12 (1883); (7) T. Moureaux,
+  _Ann. du Bureau Central Met._ (Annee 1893), 1 Mem. p. B 23; (8) P.
+  Bachmetjew, _Mem. de l'Academie St-Petersbourg_, vol. 12, No. 3
+  (1901); (9) _Terrestrial Magnetism_, vol. 3 (1898), p. 130; (10)
+  _Journal Tel. Engineers_ (1881); (11) _Proc. R.S._ vol. 52 (1892), p.
+  191; (12) _Akad. Abhandlung_ (Helsingfors, 1888); (13) _Acad. Napoli
+  Rend._ (1890), and _Atti_ (1894, 1895); (14) _Pogg. Ann._ vol. 76, p.
+  135; (15) _Proc. R.S.E._ vol. 13, p. 530; (16) A. Ruecker, _Phil. Mag._
+  1 (1901), p. 423, and R.T. Glazebrook, ibid. p. 432; (17) J. Edler,
+  _Elektrotech. Zeit._ vol. 20 (1899); (18) L.A. Bauer, _Terrestrial
+  Magnetism_, vol. 11 (1906), p. 53.     (C. Ch.)
+
+
+
+
+EARTH-NUT, the English name for a plant known botanically as _Conopodium
+denudatum_ (or _Bunium flexuosum_), a member of the natural order
+Umbelliferae, which has a brown tuber-like root-stock the size of a
+chestnut. It grows in woods and fields, has a slender flexuous smooth
+stem 2 to 3 ft. high, much-divided leaves, and small white flowers in
+many-rayed terminal compound umbels. Boswell Syme, in _English Botany_,
+iv. 114, says: "The common names of this plant in England are various.
+It is known as earth-nut, pig-nut, ar-nut, kipper-nut, hawk-nut,
+jar-nut, earth-chestnut and ground-nut. Though really excellent in taste
+and unobjectionable as food, it is disregarded in England by all but
+pigs and children, both of whom appreciate it and seek eagerly for it."
+Dr Withering describes the roots as little inferior to chestnuts. In
+Holland and elsewhere on the continent of Europe they are more
+generally eaten.
+
+
+
+
+EARTH PILLAR, a pillar of soft rock, or earth, capped by some harder
+material that has protected it from denudation. The "bad lands" of
+western North America furnish numerous examples. Here "the formations
+are often beds of sandstone or shale alternating with unindurated beds
+of clay. A semi-arid climate where the precipitation is much
+concentrated seems to be most favourable to the development of this type
+of formation." The country round the Dead Sea, where loose friable sandy
+clay is capped by harder rock, produces "bad-land" topography. The cap
+of hard rock gives way at the joints, and the water making its way
+downwards washes away the softer material directly under the cracks,
+which become wider, leaving isolated columns of clay capped with hard
+sandstone or limestone. These become smaller and fewer as denudation
+proceeds, the pillars standing a great height at times, until finally
+they all disappear.
+
+
+
+
+EARTHQUAKE. Although the terrible effects which often accompany
+earthquakes have in all ages forced themselves upon the attention of
+man, the exact investigation of seismic phenomena dates only from the
+middle of the 19th century. A new science has been thus established
+under the name of _seismology_ (Gr. [Greek: seismos], an earthquake).
+
+_History._--Accounts of earthquakes are to be found scattered through
+the writings of many ancient authors, but they are, for the most part,
+of little value to the seismologist. There is a natural tendency to
+exaggeration in describing such phenomena, sometimes indeed to the
+extent of importing a supernatural element into the description. It is
+true that attempts were made by some ancient writers on natural
+philosophy to offer a rational explanation of earthquake phenomena, but
+the hypotheses which their explanations involved are, as a rule, too
+fanciful to be worth reproducing at the present day. It is therefore
+unnecessary to dwell upon the references to seismic phenomena which have
+come down to us in the writings of such historians and philosophers as
+Thucydides, Aristotle and Strabo, Seneca, Livy and Pliny. Nor is much to
+be gleaned from the pages of medieval and later writers on earthquakes,
+of whom the most notable are Fromondi (1527), Maggio (1571) and
+Travagini (1679). In England, the earliest work worthy of mention is
+Robert Hooke's _Discourse on Earthquakes_, written in 1668, and read at
+a later date before the Royal Society. This discourse, though containing
+many passages of considerable merit, tended but little to a correct
+interpretation of the phenomena in question. Equally unsatisfactory were
+the attempts of Joseph Priestley and some other scientific writers of
+the 18th century to connect the cause of earthquakes with electrical
+phenomena. The great earthquake of Lisbon in 1755 led the Rev. John
+Michell, professor of mineralogy at Cambridge, to turn his attention to
+the subject; and in 1760 he published in the _Philosophical
+Transactions_ a remarkable essay on the Cause and Phenomena of
+Earthquakes. A suggestion of much scientific interest was made by Thomas
+Young, when in his _Lectures on Natural Philosophy_, published in 1807,
+he remarked that an earthquake "is probably propagated through the earth
+nearly in the same manner as a noise is conveyed through the air." The
+recognition of the fact that the seismologist has to deal with the
+investigation of wave-motion in solids lies at the very base of his
+science. In 1846 Robert Mallet communicated to the Royal Irish Academy
+his first paper "On the Dynamics of Earthquakes"; and in the following
+year W. Hopkins, of Cambridge, presented to the British Association a
+valuable report in which earthquake phenomena were discussed in some
+detail. Mallet's labours were continued for many years chiefly in the
+form of Reports to the British Association, and culminated in his great
+work on the Neapolitan earthquake of 1857. An entirely new impetus,
+however, was given to the study of earthquakes by an energetic body of
+observers in Japan, who commenced their investigations about the year
+1880, mainly through the influence of Prof. John Milne, then of Tokyo.
+Their work, carried on by means of new instruments of precision, and
+since taken up by observers in many parts of the world, has so extended
+our knowledge of earthquake-motion that seismology has now become
+practically a new department of physical science.
+
+It is hardly too much to say, however, that the earliest systematic
+application of scientific principles to the study of the effects of an
+earthquake was made by Mallet in his investigation of the Neapolitan
+earthquake mentioned above. It is true, the great Calabrian earthquake
+of 1783 had been the subject of careful inquiry by the Royal Academy of
+Naples, as also by Deodat Dolomieu and some other scientific
+authorities; but in consequence of the misconception which at that time
+prevailed with regard to the nature of seismic activity, the results of
+the inquiry, though in many ways interesting, were of very limited
+scientific value. It was reserved for Mallet to undertake for the first
+time an extensive series of systematic observations in an area of great
+seismic disturbance, with the view of explaining the phenomena by the
+application of the laws of wave-motion.
+
+
+  Neapolitan earthquake, 1857.
+
+The "Great Neapolitan Earthquake," by which more than 12,300 lives were
+lost, was felt in greater or less degree over all Italy south of the
+parallel of 42 deg., and has been regarded as ranking third in order of
+severity among the recorded earthquakes of Europe. The principal shock
+occurred at about 10 P.M. on the 16th of December 1857; but, as is
+usually the case, it had been preceded by minor disturbances and was
+followed by numerous after-shocks which continued for many months. Early
+in 1858, aided by a grant from the Royal Society, Mallet visited the
+devastated districts, and spent more than two months in studying the
+effects of the catastrophe, especially examining, with the eye of an
+engineer, the cracks and ruins of the buildings. His voluminous report
+was published in 1862, and though his methods of research and his
+deductions have in many cases been superseded by the advance of
+knowledge, the report still remains a memorable work in the history of
+seismology.
+
+Much of Mallet's labour was directed to the determination of the
+position and magnitude of the subterranean source from which the
+vibratory impulses originated. This is known variously as the _seismic
+centre_, _centrum_, _hypocentre_, _origin_ or _focus_. It is often
+convenient to regard this centre theoretically as a point, but
+practically it must be a locus or space of three dimensions, which in
+different cases varies much in size and shape, and may be of great
+magnitude. That part of the surface of the earth which is vertically
+above the centre is called the _epicentre_; or, if of considerable area,
+the epicentral or epifocal tract. A vertical line joining the epicentre
+and the focus was termed by Mallet the _seismic vertical_. He calculated
+that in the case of the Neapolitan earthquake the focal cavity was a
+curved lamelliform fissure, having a length of about 10 m. and a height
+of about 31/2 m., whilst its width was inconsiderable. The central point
+of this fissure, the theoretical seismic centre, he estimated to have
+been at a depth of about 61/2 m. from the surface. Dr C. Davison, in
+discussing Mallet's data, was led to the conclusion that there were two
+distinct foci, possibly situated on a fault, or plane of dislocation,
+running in a north-west and south-east direction. Mallet located his
+epicentre near the village of Caggiano, not far from Polla, while the
+other seems to have been in the neighbourhood of Montemurro, about 25 m.
+to the south-east.
+
+The intensity, or violence, of an earthquake is greatest in or near the
+epicentre, whence it decreases in all directions. A line drawn through
+points of equal intensity forms a curve round the epicentre known as an
+_isoseist_, an _isoseismal_ or an _isoseismic line_. If the intensity
+declined equally in all directions the isoseismals would be circles, but
+as this is rarely if ever the case in nature they usually become
+ellipses and other closed curves. The tract which is most violently
+shaken was termed by Mallet the _meizoseismic area_, whilst the line of
+maximum destruction is known as the _meizoseismic line_. That isoseismal
+along which the decline of energy is most rapid was called by K. von
+Seebach a _pleistoseist_.
+
+In order to determine the position of the seismic centre, Mallet made
+much use of the cracks in damaged buildings, especially in walls of
+masonry, holding that the direction of such fractures must generally be
+at right angles to that in which the normal earthquake-wave reached
+them. In this way he obtained the "angle of emergence" of the wave. He
+also assumed that free-falling bodies would be overthrown and projected
+in the direction of propagation of the wave, so that the epicentre might
+immediately be found from the intersection of such directions. These
+data are, however, subject to much error, especially through want of
+homogeneity in the rocks, but Mallet's work was still of great value.
+
+
+  Charleston earthquake, 1886.
+
+A different method of ascertaining the depth of the focus was adopted by
+Major C.E. Dutton in his investigation of the Charleston earthquake of
+the 31st of August 1886 for the U.S. Geological Survey. This catastrophe
+was heralded by shocks of greater or less severity a few days previously
+at Summerville, a village 22 m. north-west of Charleston. The great
+earthquake occurred at 9.51 P.M., standard time of the 75th meridian,
+and in about 70 seconds almost every building in Charleston was more or
+less seriously damaged, while many lives were lost. The epicentral tract
+was mainly a forest region with but few buildings, and the principal
+records of seismological value were afforded by the lines of railway
+which traversed the disturbed area. In many places these rails were
+flexured and dislocated. Numerous fissures opened in the ground, and
+many of these discharged water, mixed sometimes with sand and silt,
+which was thrown up in jets rising in some cases to a height of 20 ft.
+Two epicentres were recognized--one near Woodstock station on the South
+Carolina railway, and the other, being the centre of a much smaller
+tract, about 14 m. south-west of the first and near the station of
+Rantowles on the Charleston and Savannah line. Around these centres and
+far away isoseismal lines were drawn, the relative intensity at
+different places being roughly estimated by the effects of the
+catastrophe on various structures and natural objects, or, where visible
+records were wanting, by personal evidence, which is often vague and
+variable. The Rossi-Forel scale was adopted. This is an arbitrary scale
+formulated by Professor M.S. de Rossi, of Rome, and Dr F.A. Forel, of
+Geneva, based mostly on the ordinary phenomena observed during an
+earthquake, and consisting of ten degrees, of which the lowest is the
+feeblest, viz. I. Microseismic shock; II. Extremely feeble shock; III.
+Very feeble shock; IV. Feeble; V. Shock of moderate intensity; VI.
+Fairly strong shock; VII. Strong shock; VIII. Very strong shock; IX.
+Extremely strong shock; X. Shock of extreme intensity. Other
+conventional scales, some being less detailed, have been drawn up by
+observers in such earthquake-shaken countries as Italy and Japan. A
+curve, or theoretical isoseismal, drawn through certain points where the
+decline of intensity on receding from the epicentre seems to be greatest
+was called by Dutton an "index-circle"; and it can be shown that the
+radius of such a circle multiplied by the square root of 3 gives the
+focal depth theoretically. In this way it was computed that in the
+Charleston earthquake the origin under Woodstock must have had a depth
+of about 12 m. and that near Rantowles a depth of nearly 8 m. The
+determination of the index-circle presents much difficulty, and the
+conclusions must be regarded as only approximate.
+
+It is probable, according to R.D. Oldham, that local earthquakes may
+originate in the "outer skin" of the earth, whilst a large world-shaking
+earthquake takes its origin in the deeper part of the "crust," whence
+such a disturbance is termed a _bathyseism_. Large earthquakes may have
+very extended origins, with no definite centre, or with several foci.
+
+
+  Great Indian earthquake, 1897.
+
+The gigantic disaster known as the "Great Indian Earthquake," which
+occurred on the 12th of June 1897, was the subject of careful
+investigation by the Geological Survey of India and was described in
+detail by the superintendent, R.D. Oldham. It is sometimes termed the
+Assam earthquake, since it was in that province that the effects were
+most severe, but the shocks were felt over a large part of India, and
+indeed far beyond its boundaries. Much of the area which suffered most
+disturbance was a wild country, sparsely populated, with but few
+buildings of brick or stone from which the violence of the shocks could
+be estimated. The epicentral tract was of great size, having an
+estimated area of about 6000 sq. m., but the mischief was most severe in
+the neighbourhood of Shillong, where the stonework of bridges, churches
+and other buildings was absolutely levelled to the ground. After the
+main disturbance, shocks of greater or less severity continued at
+intervals for many weeks. It is supposed that this earthquake was
+connected with movement of subterranean rock-masses of enormous
+magnitude along a great thrust-plane, or series of such planes, having a
+length of about 200 m. and a maximum breadth of not less than 50 m. It
+is pointed out by Oldham that this may be compared for size with the
+great Faille du Midi in Belgium, which is known to extend for a distance
+of 120 m. The depth of the principal focus, though not actually capable
+of determination, was probably less than 5 m. from the surface. From the
+focus many secondary faults and fractures proceeded, some reaching the
+surface of the ground. Enormous landslips accompanied the earthquake,
+and as an indirect effect of these slides the form of the water-courses
+became in certain cases modified. Permanent changes of level were also
+observed.
+
+
+  Kangra earthquake, 1905.
+
+Eight years after the great Assam earthquake India was visited by
+another earthquake, which, though less intense, resulted in the loss of
+about 20,000 lives. This catastrophe is known as the Kangra earthquake,
+since its centre seems to have been located in the Kangra valley, in the
+north-west Himalaya. It occurred on the 4th of April 1905, and the first
+great shocks were felt in the chief epifocal district at about 6.9 a.m.,
+Madras time. Although the tract chiefly affected was around Kangra and
+Dharmsala, there was a subordinate epifocal tract in Dehra Dun and the
+neighbourhood of Mussoorie, whilst the effects of the earthquake
+extended in slight measure to Lahore and other cities of the plain. It
+is estimated that the earthquake was felt over an area of about
+1,625,000 m. Immediately after the calamity a scientific examination of
+its effects was made by the Geological Survey of India, and a report was
+drawn up by the superintendent, C.S. Middlemiss.
+
+
+  California earthquake, 1906.
+
+The great earthquake, which, with the subsequent fire, wrought such
+terrible destruction in and around San Francisco on the 18th of April
+1906, was the most disastrous ever recorded in California. It occurred
+between 10 and 15 minutes after 5 A.M., standard time of the 120th
+meridian. The moment at which the disaster began and the duration of the
+shock varied at different localities in the great area over which the
+earthquake was felt. At San Francisco the main shock lasted rather more
+than one minute.
+
+According to the official Report, the earthquake was due to rupture and
+movement along the plane of the San Andreas fault, one of a series which
+runs for several hundred miles approximately in a N.W. and S.E.
+direction near the coast line. Evidence of fresh movement along this
+plane of dislocation was traced for a distance of 190 m. from San Juan
+on the south to Point Arena on the north. There the trace of the fault
+is lost beneath the sea, but either the same fault or another appears 75
+m. to the north at Point Delgada. The belt of disturbed country is
+notoriously unstable, and part of the fault had been known as the
+"earthquake crack." The direction is marked by lines of straight cliffs,
+long ponds and narrow depressions, forming a Rift, or old line of
+seismic disturbance. According to Dr G.K. Gilbert the earthquake zone
+has a length of 300 or 400 m. The principal displacement of rock, in
+1906, was horizontal, amounting generally to about 10 ft. (maximum 21
+ft.), but there was also locally a slight vertical movement, which
+towards the north end of the fault reached 3 ft. Movement was traced for
+a distance of about 270 m., and it is estimated that at least 175,000
+sq. m. of country must have been disturbed. In estimating the intensity
+of the earthquake in San Francisco a new scale was introduced by H.O.
+Wood. The greatest structural damage occurred on soft alluvial soil and
+"made ground." Most of the loss of property in San Francisco was due to
+the terrible fire which followed the earthquake and was beyond control
+owing to the destruction of the system of water-supply.
+
+Immediately after the catastrophe a California Earthquake Investigation
+Committee was appointed by the governor of the state; and the American
+Association for the Advancement of Science afterwards instituted a
+Seismological Committee. The elaborate Report of the State Investigation
+Committee, by the chairman, Professor A.C. Lawson, was published in
+1908.
+
+On the 17th of August 1906 a disastrous earthquake occurred at
+Valparaiso, and the year 1906 was marked generally by exceptional
+seismic activity.
+
+The Jamaica earthquake of the 14th of January 1907 appears to have
+accompanied movement of rock along an east and west fracture or series
+of fractures under the sea a few miles from the city of Kingston. The
+statue of Queen Victoria at Kingston was turned upon its pedestal the
+eighth of a revolution.
+
+
+  Messina earthquake, 1908.
+
+A terrible earthquake occurred in Calabria and Sicily on December 28,
+1908, practically destroying Messina and Reggio. According to the
+official returns the total loss of life was 77,283. Whilst the principal
+centre seems to have been in the Strait of Messina, whence the
+disturbance is generally known as the Messina earthquake, there were
+independent centres in the Calabrian peninsula, a country which had been
+visited by severe earthquakes not long previously, namely on September
+8, 1905, and October 23, 1907. The principal shock of the great Messina
+earthquake of 1908 occurred at 5.21 A.M. (4.21 Greenwich time), and had
+a duration of from 30 to 40 seconds. Neither during nor immediately
+before the catastrophe was there any special volcanic disturbance at
+Etna or at Stromboli, but it is believed that there must have been
+movement along a great plane of weakness in the neighbourhood of the
+Strait of Messina, which has been studied by E. Cortese. The sea-floor
+in the strait probably suffered great disturbance, resulting in the
+remarkable movement of water observed on the coast. At first the sea
+retired, and then a great wave rolled in, followed by others generally
+of decreasing amplitude, though at Catania the second was said to have
+been greater than the first. At Messina the height of the great wave was
+2.70 metres, whilst at Ali and Giardini it reached 8.40 metres and at
+San Alessio as much as 11.7 metres. At Malta the tide-gauge recorded a
+wave of 0.91 metre. The depth of the chief earthquake-centre was
+estimated by Dr E. Oddone at about 9 kilometres. The earthquake and
+accompanying phenomena were studied also by Professor A. Ricco, Dr M.
+Baratta and Professor G. Platania and by Dr F. Omori of Tokyo. After the
+great disturbance, shocks continued to affect the region intermittently
+for several months. In certain respects the earthquake of 1908 presented
+much resemblance to the great Calabrian catastrophe of 1783.
+
+It has been proposed by R.D. Oldham that the disturbance which causes
+the fracture and permanent displacement of the rocks during an
+earthquake should be called an "earthshake," leaving the term earthquake
+especially for the vibratory motion. The movement of the earthquake is
+molecular, whilst that of the earthshake is molar. Subsequently he
+suggested the terms _mochleusis_ and _orchesis_ ([Greek: mochleuo], I
+heave; [Greek: orcheomai], I dance), to denote respectively the molar
+and the molecular movement, retaining the word earthquake for use in its
+ordinary sense.
+
+In most earthquakes the proximate cause is generally regarded as the
+fracture and sudden movement of underground rock-masses. Disturbances of
+this type are known as "tectonic" earthquakes, since they are connected
+with the folding and faulting of the rocks of the earth's crust. They
+indicate a relief of the strain to which the rock-masses are subjected
+by mountain-making and other crustal movements, and they are
+consequently apt to occur along the steep face of a table-land or the
+margin of a continent with a great slope from land to sea. In many cases
+the immediate seat of the originating impulse is located beneath the
+sea, giving rise to submarine disturbances which have been called
+"seaquakes." Much attention has been given to these suboceanic
+disturbances by Professor E. Rudolph.
+
+Professor J.H. Jeans has pointed out that the regions of the earth's
+crust most affected by earthquakes lie on a great circle corresponding
+with the equator of the slightly pear-shaped figure that he assigns to
+the earth. This would represent a belt of weakness, subject to crushing,
+from the tendency of the pear to pass into a spherical or spheroidal
+form under the action of internal stresses. According to the comte de
+Montessus de Ballore, the regions of maximum seismic instability appear
+to be arranged on two great circles, inclined to each other at about
+67 deg.. These are the Circumpacific and Mediterranean zones.
+
+Maps of the world, showing the origins of large earthquakes each year,
+accompany the Annual Reports of the Seismological Committee of the
+British Association, drawn up by Professor Milne. It is important to
+note that Professor Milne has shown a relationship between
+earthquake-frequency and the wandering of the earth's pole from its mean
+position. Earthquakes seem to have been most frequent when the
+displacement of the pole has been comparatively great, or when the
+change in the direction of movement has been marked. Valuable earthquake
+catalogues have been compiled at various times by Alexis Perrey, R. and
+J.W. Mallet, John Milne, T. Oldham, C.W.C. Fuchs, F. de Montessus de
+Ballore and others.
+
+
+  British earthquakes.
+
+Such earthquakes as are felt from time to time in Great Britain may
+generally be traced to the formation of faults, or rather to incidents
+in the growth of old faults. The East Anglian earthquake of the 22nd of
+April 1884--the most disastrous that had occurred in the British Isles
+for centuries--was investigated by Prof. R. Meldola and W. White on
+behalf of the Essex Field Club. The shocks probably proceeded from two
+foci--one near the villages of Peldon and Abberton, the other near
+Wivenhoe and Rowhedge, in N.E. Essex. It is believed that the
+superficial disturbance resulted from rupture of rocks along a deep
+fault. An attempt has been made by H. Darwin, for the Seismological
+Committee of the British Association, to detect and measure any gradual
+movement of the strata along a fault, by observation at the Ridgeway
+fault, near Upway, in Dorsetshire. Dr C. Davison in studying the
+earthquakes which have originated in Britain since 1889 finds that
+several have been "twins." A twin earthquake has two maxima of intensity
+proceeding from two foci, whereas a double earthquake has its successive
+impulses from what is practically a single focus. The Hereford
+earthquake of December 1896, which resulted in great structural damage,
+was a twin, having one epicentre near Hereford and the other near Ross.
+Davison refers it to a slip along a fault-plane between the anticlinal
+areas of Woolhope and May Hill; and according to the same authority the
+Inverness earthquake of the 18th of September 1901 was referable to
+movement along a fault between Loch Ness and Inverness. The South Wales
+earthquake of June 27, 1906, was probably due to movement connected with
+the Armorican system of folds, striking in an east and west direction.
+
+It may be noted that when a slip occurs along a fault, the displacement
+underground may be but slight and may die out before reaching the
+surface, so that no scarp is formed. In connexion, however, with a
+seismic disturbance of the first magnitude the superficial features may
+be markedly affected. Thus, the great Japan earthquake of October
+1891--known often as the Mino-Owari earthquake--was connected with the
+formation or development of a fault which, according to Professor B.
+Koto, was traced on the surface for a distance of nearly 50 m. and
+presented in places a scarp with a vertical throw of as much as 20 ft.,
+while probably the maximum displacement underground was very much
+greater.
+
+Although most earthquakes seem to be of tectonic type, there are some
+which are evidently connected, directly or indirectly, with volcanic
+activity (see VOLCANO). Such, it is commonly believed, were the
+earthquakes which disturbed the Isle of Ischia in 1881 and 1883, and
+were studied by Professor J. Johnston-Lavis and G. Mercalli. In addition
+to the tectonic and volcanic types, there are occasional earthquakes of
+minor importance which may be referred to the collapse of the roof of
+caverns, or other falls of rock in underground cavities at no great
+depth. According to Prof. T.J.J. See most earthquakes are due, directly
+or indirectly, to the explosive action of ste by the leakage of
+sea-water through the ocean floor.
+
+
+  Earthquake waves.
+
+Whatever the nature of the impulse which originates the earthquake, it
+gives rise to a series of waves which are propagated through the earth's
+substance and also superficially. In one kind, known as normal or
+condensational waves, or waves of elastic compression, the particles
+vibrate to and from the centre of disturbance, moving in the direction
+in which the wave travels, and therefore in a way analogous to the
+movement of air in a sound-wave. Associated with this type are other
+waves termed transverse waves, or waves of elastic distortion, in which
+the particles vibrate across or around the direction in which the wave
+is propagated. The normal waves result from a temporary change of volume
+in the medium; the transverse from a change of shape. The distance
+through which an earth-particle moves from its mean position of rest,
+whether radially or transversely, is called the amplitude of the wave;
+whilst the double amplitude, or total distance of movement, to and fro
+or up and down, like the distance from crest to trough of a water wave,
+may be regarded as the range of the wave. The period of a wave is the
+time required for the vibrating particle to complete an oscillation. As
+the rocks of the earth's crust are very heterogeneous, the
+earthquake-waves suffer refraction and reflection as they pass from one
+rock to another differing in density and elasticity. In this way the
+waves break up and become much modified in course of transmission, thus
+introducing great complexity into the phenomena. It is known that the
+normal waves travel more rapidly than the transverse.
+
+Measurements of the surface speed at which earthquake-waves travel
+require very accurate time-measurers, and these are not generally
+available in earthquake-shaken regions. Observations during the
+Charleston earthquake of 1886 were at that time of exceptional value,
+since they were made over a large area where standard time was kept.
+Lines drawn through places around the epicentre at which the shock
+arrives at the same moment are called coseismal lines. The motion of the
+wave is to be distinguished from the movement of the vibrating
+particles. The velocity of the earth-particle is its rate of movement,
+but this is constantly changing during the vibration, and the rate at
+which the velocity changes is technically called the acceleration of the
+particle.
+
+Unfelt movements of the ground are registered in the earthquake records,
+or seismograms, obtained by the delicate instruments used by modern
+seismologists. From the study of the records of a great earthquake from
+a distant source, sometimes termed a teleseismic disturbance, some
+interesting inferences have been drawn with respect to the constitution
+of the interior of the earth. The complete record shows two phases of
+"preliminary tremors" preceding the principal waves. It is believed that
+while the preliminary tremors pass through the body of the earth, the
+principal waves travel along or parallel to the surface. Probably the
+first phase represents condensational, and the second phase
+distortional, waves. Professor Milne concludes from the speed of the
+waves at different depths that materials having similar physical
+properties to those at the surface may extend to a depth of about 30 m.,
+below which they pass into a fairly homogeneous nucleus. From the
+different rates of propagation of the precursors it has been inferred by
+R.D. Oldham that below the outer crust, which is probably not everywhere
+of the same thickness, the earth is of practically uniform character to
+a depth of about six-tenths of the radius, but the remaining four-tenths
+may represent a core differing physically and perhaps chemically from
+the outer part. Oldham also suggests, from his study of oceanic and
+continental wave-paths, that there is probably a difference in the
+constitution of the earth beneath oceans and beneath continents.
+
+The surface waves, which are waves of great length and long period and
+are propagated to great distances with practically a constant velocity,
+have been regarded as quasi-elastic gravitational waves. Further, in a
+great earthquake the surface of the ground is sometimes visibly agitated
+in the epifocal district by undulations which may be responsible for
+severe superficial damage. (See also for elastic waves ELASTICITY, Sec.
+89.)
+
+An old classification of earthquake-shocks, traces of which still linger
+in popular nomenclature, described them as "undulatory," when the
+movement of the ground was mainly in a horizontal direction;
+"subsultory," when the motion was vertical, like the effect of a normal
+wave at the epicentre; and "vorticose," when the movement was rotatory,
+apparently due to successive impulses in varying directions.
+
+The sounds which are associated with seismic phenomena, often described
+as subterranean rumbling and roaring, are not without scientific
+interest, and have been carefully studied by Davison. "Isacoustic lines"
+are curves drawn through places where the sound is heard by the same
+percentage of observers. The sound is always low and often inaudible to
+many.
+
+The refined instruments which are now used by seismologists for
+determining the elements of earthquake motion and for recording
+earthquakes from distant origins are described in the article
+SEISMOMETER. These instruments were developed as a consequence of the
+attention given in modern times to the study of earthquakes in the Far
+East.     (F. W. R.*)
+
+
+  Seismology in Japan.
+
+Strange as it may appear, the advances that have been made in the study
+of earthquakes and the world-wide interest shown in their phenomena were
+initiated in work commenced in Japan. When the Japanese government,
+desiring to adopt Western knowledge, invited to its shores bodies of men
+to act as its instructors, the attention of the newcomers was naturally
+attracted to the frequent shakings of the ground. Interest in these
+phenomena increased more rapidly than their frequency, and at length it
+was felt that something should be done for their systematic study. At
+midnight on the 22nd of February 1880 movements more violent than usual
+occurred; chimneys were shattered or rotated, tiles slid down from
+roofs, and in the morning it was seen that Yokohama had the appearance
+of a city that had suffered a bombardment. The excitement was intense,
+and before the ruins had been removed a meeting was convened and the
+Seismological Society of Japan established. The twenty volumes of
+original papers published by this body summarize to a large extent the
+results of the later study of seismology.[1]
+
+The attention of the students of earthquakes in Japan was at first
+directed almost entirely to seismometry or earthquake measurement. Forms
+of apparatus which then existed, as for example the seismographs,
+seismometers and seismoscopes of Mallet, Palmieri and others, were
+subjected to trial; but inasmuch as they did little more than indicate
+that an earthquake had taken place--the more elaborate forms recording
+also the time of its occurrence--they were rapidly discarded, and
+instruments were constructed to _measure_ earthquake motion. Slightly
+modified types of the new instruments devised in Japan were adopted
+throughout the Italian peninsula, and it is fair to say that the
+seismometry developed in Japan revolutionized the seismometry of the
+world. The records obtained from the new instruments increased our
+knowledge of the character of earthquake motion, and the engineer and
+the architect were placed in a position to construct so that the effects
+of known movements could be minimized. It was no doubt the marked
+success, both practical and scientific, attending these investigations
+that led the Japanese government to establish a chair of seismology at
+its university, to organize a system of nearly 1000 observing stations
+throughout the country, and in 1893 to appoint a committee of scientific
+and practical men to carry out investigations which might palliate the
+effects of seismic disturbances. In the first year this committee
+received a grant of L5000, and as liberal sums for the same purpose
+appear from time to time in the parliamentary estimates, it may be
+assumed that the work has been fraught with good results. In their
+publications we find not only records of experiences and experiments in
+Japan, but descriptions and comments upon earthquake effects in other
+countries. In two of the volumes there are long and extremely well
+illustrated accounts of the earthquake which on the 12th of June 1897
+devastated Assam, to which country two members of the above-mentioned
+committee were despatched to gather such information as might be of
+value to the architect and builder in earthquake-shaken districts.
+
+
+  Seismological research.
+
+A great impetus to seismological investigation in Europe and America was
+no doubt given by the realization of the fact that a large earthquake
+originating in any one part of the world may be recorded in almost any
+other. Italy for many years past has had its observatories for recording
+earthquakes which can be felt, and which are of local origin, but at the
+present time at all its first-class stations we find instruments to
+record the unfelt movements due to earthquakes originating at great
+distances, and as much attention is now paid to the large earthquakes of
+the world as to the smaller ones originating within Italian
+territory.[2] The _Kaiserliche Akademie der Wissenschaften_ of Vienna
+established earthquake observatories in Austria,[3] and the Central
+Observatorium of St Petersburg has carried out similar work in Russia.
+Germany attached a seismological observatory to its university at
+Strassburg, whilst provision has been made for a professorship of Earth
+Physics (_Geophysik_) at Goettingen.[4] In accordance with the
+recommendation of the British Association, seismographs of a similar
+character have been installed at stations all over the world.[5] The
+principal objects of this extended and still extending system of
+stations are to determine the velocity with which motion is propagated
+over the surface and through the interior of the earth, to locate the
+positions of sub-oceanic earthquake origins, and generally to extend our
+knowledge respecting the physical nature of the planet on which we live.
+
+
+  Frequency of earthquakes.
+
+We now know that earthquakes are many times more frequent than was
+previously supposed. In Japan, for example, between 1885 and 1892 no
+fewer than 8331 were recorded--that is to say, on the average there were
+during that time more than 1000 disturbances per year. Although many of
+these did not cause a sensible shaking over areas exceeding a few
+hundred square miles, many of them were sufficiently intense to
+propagate vibrations round and through the globe. If we pick out the
+well-marked earthquake districts of the world, and give to each of them
+a seismicity or earthquake frequency per unit area one-third of that in
+Japan, the conclusion arrived at is that considerable areas of our
+planet are on the average shaken every half-hour.
+
+
+  Volcanoes and earthquakes.
+
+The knowledge which we now possess respecting the localities where
+earthquakes are frequent and the forms of the foci from which they have
+spread, enables us to speak definitely respecting the originating causes
+of many of these phenomena. It is found, for example, that although in
+many countries there may be displays of volcanic and seismic activity
+taking place almost side by side, it is only rarely that there is direct
+relationship between the two. Now and then, however, before a volcano
+breaks into eruption there may be a few ineffectual efforts to form a
+vent, each of which is accompanied by no more than a slight local
+shaking of the ground. This is true even for the largest and most
+violent eruptions, when mountains have with practically a single effort
+blown off their heads and shoulders. Thus the earthquake which
+accompanied the eruption of Bandaisan, in central Japan, in 1888 was
+felt only over a radius of 25 m. The analyses of the seismic registers
+of Japan clearly indicate that comparatively few shakings originate near
+to the volcanoes of the country, the majority of them, like those of
+many other countries, coming from regions where volcanic rocks are
+absent. The greatest number spread inland from the Pacific seaboard, the
+movement becoming more and more feeble as it approaches the backbone of
+the country, which is drilled with numerous volcanic vents. What is true
+for Japan is generally true for the western coasts of North and South
+America.
+
+
+  Origin of earthquakes.
+
+Speaking broadly, earthquakes are most frequent along the steeper
+flexures in the earth's surface, and in those regions where there is
+geological evidence to show that slow secular movements in the earth's
+crust are possibly yet in progress. With a unit distance of 2 degrees,
+or 120 geographical m., we find that the slopes running eastwards from
+the highlands of Japan and westwards from the Andean ridges down into
+the Pacific vary from 1 in 20 to 1 in 30, and it is on the faces or near
+to the bottom of these slopes that seismic efforts are frequent. The
+slopes running from Australia, eastern America and western Europe into
+the neighbouring oceans vary between 1 in 70 and 1 in 250, and in these
+regions earthquakes are of rare occurrence. The seismic activity met
+with in the Himalayas and the Alps finds its best explanation in the
+fact that these mountains are geologically recent, and there are no
+reasons to doubt that the forces which brought their folds into
+existence are yet in action.
+
+This peculiar association of earthquakes with pronounced topographical
+configuration and certain geological conditions evidently indicates that
+the origin of many of them is connected with rock folding. Inasmuch as
+certain large earthquakes have been accompanied by rock fracture, as for
+example in 1891, when in central Japan a fault some 50 m. in length was
+created, whilst the origins of others have been distinctly traced to the
+line of an existing fault or its continuation, we may conclude that the
+majority of earthquakes are spasmodic accelerations in the secular
+movements which are creating (and in some instances possibly
+obliterating) the more prominent features of the earth's surface. These
+secular movements, which include upheavals, subsidences, horizontal
+displacements--all of which are explained on the assumption of a crust
+seeking support on a nucleus gradually contracting by loss of heat, are
+collectively referred to as bradyseismical ([Greek: bradys], slow)
+movements. To these may be added movements directly attributable to the
+influence of gravity. Sub-oceanic districts in a state of seismic strain
+may be so far loaded by the accumulation of sediments that gentle
+bending may be accompanied by sudden yieldings. This possibly accounts
+for the frequency of earthquakes off the mouth of the Tonegawa on the
+eastern side of Japan. The distortions so frequently observed in fossils
+and pebbles, the varying thickness of contorted strata, and the "creep"
+in coal-mines, together with other phenomena, indicate that rocks may
+flow. Observations of this nature lead to the supposition that high
+plateau-like regions may be gradually subsiding under the influence of
+their own weight, and that the process of settlement may from time to
+time be spasmodic in its character. Whether the earthquakes which
+originate round the submerged basal frontiers of the continents bounding
+the Pacific are ever attributable to such activities, it is impossible
+to say. All that we know with certainty is that they are sometimes
+accompanied by such a vast displacement of material that the ocean has
+been set into a state of oscillation for periods of 24 hours, that in
+some instances there have been marked changes in depth, and that
+enormous sub-oceanic landslips have occurred. These phenomena are,
+however, equally well explained on the assumption of sudden faulting
+accompanied by violent shaking, which would dislodge steeply inclined
+beds of material beneath the ocean as it does upon the land.
+
+
+  Two types of earthquake motion.
+
+Although the proximate cause of earthquake motion is traced to sudden
+yieldings in the crust of the earth brought about by some form of
+bradyseismical action, the existence of at least two distinct types of
+seismic motion indicates that the mechanical conditions accompanying the
+fracturing of rocks are not always identical. 90 or 95% of the
+earthquakes which can be recorded consist of elastic or quasi-elastic
+vibrations. The remainder, including the large earthquakes, not only
+exhibit the elastic movements, but are accompanied by surface
+undulations which are propagated most certainly for some hundreds of
+miles round their origin, and then as horizontal movements sweep over
+the whole surface of the globe. The former of these may accompany the
+formation of a new fault or the sudden renewal of movement along an old
+one; they are cracking or rending effects, without any great
+displacement. The latter are probably fracturings accompanied by
+vertical and horizontal displacements of masses of the earth's crust
+sufficiently great to set up the observed surface undulations. These
+shocks are so frequently followed a few minutes later by disturbances,
+which from their similarity to the movements which have preceded them
+may be called earthquake echoes, that we are led to the speculation that
+we are here dealing with the caving-in of ill-supported portions of the
+earth's crust, the waves from which are radiated to boundaries and then
+returned to their origin to coalesce and give rise to a second impulse
+not unlike the primary. Succeeding the first repetition of motion
+recorded by the seismograph there is often a rhythmical repetition of
+similar wave groups, suggesting the existence within our earth of
+phenomena akin to multiple echoes.
+
+
+  Character of earthquake motion.
+
+The introduction of new methods into seismometry quickly revolutionized
+our ideas respecting the character of earthquake motion. Although an
+earthquake may be strongly felt within a distance of 50 m. from its
+origin, and although the movements in the upper storeys of buildings
+within the shaken area may be large, the actual range of the horizontal
+motion of the ground is usually less than {1/10} of an inch. With such
+earthquakes ordinary seismographs for recording vertical motion do not
+show any disturbance. When the movement reaches 1/2 in. it becomes
+dangerous, and a back-and-forth movement of an inch is usually
+accompanied by destructive effects. In this latter case the amplitude of
+the vertical record which indicates the existence of surface waves will
+vary between 1/2 and {1/100} of an inch. In the earthquake which
+devastated central Japan on the 26th of October 1891, nearly every
+building within the epifocal district fell, the ground was fissured,
+forests slipped down from mountain sides to dam up valleys, whilst the
+valleys themselves were permanently compressed. The horizontal movements
+seem to have reached 9 in. or 1 ft., and the surface undulations were
+visible to the eye.
+
+
+  Period and duration.
+
+The rapidity with which the movements are performed varies throughout a
+disturbance. A typical earthquake usually commences with minute elastic
+vibrations, the periods of which vary between {1/5} and {1/20} of a
+second. These are recorded by seismographs, and are noticed by certain
+of the lower animals like pheasants, which before the occurrence of
+movement perceptible to human beings scream as if alarmed. When an
+earthquake is preceded by a sound we have evidence of preliminary
+tremors even more rapid than those recorded by seismographs. Following
+these precursors there is a shock or shocks, the period of which will be
+1 or 2 seconds. From this climax the movements, although irregular in
+character, become slower and smaller until finally they are
+imperceptible. The duration of a small earthquake usually varies from a
+few seconds to a minute, but large earthquakes, which are accompanied by
+surface undulations, may be felt for 2 or 3 minutes, whilst an ordinary
+seismograph indicates a duration of from 6 to 12 minutes. A free
+horizontal pendulum tells us that with severe earthquakes the ground
+comes to rest by a series of more or less rhythmical surgings,
+continuing over 1 or 2 hours. Although the maximum displacement has a
+definite direction, the successive vibrations are frequently performed
+in many different azimuths. The predominating direction at a given
+station in certain instances is apparently at right angles to the strike
+of the neighbouring strata, this being the direction of easiest
+yielding.
+
+
+  Velocity.
+
+Earthquake motion as recorded at stations several thousands of miles
+distant from its origin exhibits characteristics strikingly different
+from those just described. The precursors now show periods of from 1 to
+5 seconds, whilst the largest movements corresponding to the shocks may
+have periods of from 20 to 40 seconds. The interval of time by which the
+first tremors have outraced the maximum movement has also become
+greater. Within a few hundreds of miles from an origin this interval
+increases steadily, the velocity of propagation of the first movements
+being about 2 km. per second, whilst that of the latter may be taken at
+about 1.6 km. per second. Beyond this distance the velocity of
+transmission of the first movements rapidly increases, and for great
+distances, as for example from Japan to England, it is higher than we
+should expect for waves of compression passing through steel or glass.
+This observation precludes the idea that these preliminary tremors have
+travelled through the heterogeneous crust of the earth, and since the
+average velocity of their transmission increases with the length of the
+path along which they have travelled, and we but rarely obtain certain
+evidence that a seismograph has been disturbed by waves which have
+reached it by travelling in opposite directions round the world, we are
+led to the conclusion that earthquake precursors pass through our earth
+and not round its surface. The following table relating to earthquakes,
+which originated off the coast of Borneo on the 20th and 27th of
+September 1897, is illustrative of the velocities here considered:--
+
+  +---------------------------+-----------+-------------+---------------+
+  |                           |           |             |       _______ |
+  |                           | Distance  |  Velocity   |      /Average |
+  |        Localities         |   from    |   in kms.   |     /depth of |
+  |                           |  origin   | per sec. if |  \ / chord in |
+  |                           |in degrees.|  on chord.  | 1/4 V  kms.     |
+  +---------------------------+-----------+-------------+---------------+
+  | Nicolaieff                |    81 deg.    |     8.1     |      8.0      |
+  | Potsdam                   |    92 deg.    |     8.4     |      9.1      |
+  | Catania, Ischia, Rocca di |           |             |               |
+  |   Papa, Rome              |    96 deg.    |     9.0     |      9.5      |
+  | Isle of Wight             |   103 deg.    |     9.8     |     10.2      |
+  +---------------------------+-----------+-------------+---------------+
+
+The chords referred to here are those joining the earthquake origins and
+distant observing stations, and it will be noted that one-quarter of the
+square root of the average depths at which these run closely corresponds
+to observed average velocities if wave paths followed chords. This
+increase of velocity with average depth shows that the paths followed
+through the earth must be curved with their convexity towards the centre
+of the earth. These observations do not directly tell us to what extent
+a true wave path is deflected from the direction of a chord, but they
+suggest as an extremely plausible assumption that the square of the
+speed is a linear function of the depth below the surface of the earth.
+With this assumption Dr C.G. Knott shows that the square of the speed
+(v squared) can be expressed linearly in terms of the average depth of the
+chord d, thus: v squared = 2.9 + .026 d, the units being miles and seconds. The
+formula applies with fair accuracy to moderate and high values of d, but
+it gives too high a value for short chords. It follows that the square
+of the speed increases 0.9% per mile of descent in the earth. The
+conclusion we arrive at is that the preliminary tremors which pass
+through the earth do so in the vicinity of their origin at the rate of
+almost 2.3 km. per second. This velocity increases as the wave path
+plunges downwards, attaining in the central regions a velocity of 16 to
+17 kms., whilst the highest average velocity which is across a diameter
+lies between 10 and 12 kms. per second.
+
+The large surface waves radiating from an origin to a distant place have
+velocities lying between 1.6 and 4 kms. per second, and it has been
+observed that when the higher velocity has been noted this refers to an
+observation at a station very remote from the origin. One explanation of
+this is the assumption that only very large waves indicating a large
+initial disturbance are capable of travelling to great distances, and as
+pointed out by R.D. Oldham, large waves under the influence of gravity
+will travel faster than small waves. These waves (which may be
+gravitational or distortional) are recorded as slow tiltings of the
+ground measured by angles of 0.5 to 10 or 15 seconds of arc, or as
+horizontal displacements of 0.5 or several millimetres. Their calculated
+lengths have reached 50 kms. (31 m.).
+
+
+  Frequency.
+
+In the section of this article relating to the cause of earthquakes a
+little has been said about their frequency or the number of times these
+phenomena are repeated during a given interval of time. It has been
+shown that all countries are very often moved by earthquakes which have
+originated at great distances. Great Britain, for example, is crossed
+about 100 times a year by earthquake waves having durations of from 3
+minutes to 3 hours, whilst the vibratory motions which originate in that
+country are not only small but of rare occurrence. In the earlier stages
+of the world's history, because the contraction of its nucleus was more
+rapid than it is at present, it is commonly inferred that phenomena
+accompanying bradyseismical activity must have been more pronounced and
+have shown themselves upon a grander scale than they do at the present
+time. Now, although the records of our rocks only carry us back over a
+certain portion of this history, they certainly represent an interval of
+time sufficiently long to furnish some evidence of such enfeeblement if
+it ever existed. So far from this being the case, however, we meet with
+distinct evidences in the later chapters of geological history of
+plutonic awakenings much more violent than those recorded at its
+commencement. During Palaeozoic times many mountain ranges were formed,
+and accompanying these orogenic processes there was marked volcanic
+activity. In the succeeding Secondary period plutonic forces were
+quiescent, but during the formation of the early Tertiaries, when some
+of the largest mountain ranges were created, they awoke with a vigour
+greater than had ever been previously exhibited. At this period it is
+not improbable that Scotland was as remarkable for its volcanoes and its
+earthquakes as Japan is at the present day. If the statement relating to
+the general decrease in bradyseismical changes referred merely to their
+frequency, and omitted reference to their magnitude, the views of the
+geologist and physicist might harmonize. One explanation for this
+divergence of opinion may rest on the fact that too little attention has
+been directed to all the conditions which accompany the adaptation of
+the earth's crust to its shrinking nucleus. As the latter grows smaller
+the puckerings and foldings of the former should grow larger. Each
+succeeding geological epoch should be characterized by mountain
+formations more stupendous than those which preceded them, whilst the
+fracturing, dislocation, caving-in of ill-supported regions, and
+creation of lines of freedom for the exhibition of volcanic activity
+which would accompany these changes, would grow in magnitude. The
+written records of many countries reflect but on a smaller scale the
+crystallized records in their hills. In 1844, at Comrie, in Perthshire,
+as many as twelve earthquakes were recorded in a single month, whilst
+now there are but one or two per year. Earthquake frequency varies with
+time. A district under the influence of hypogenic activities reaches a
+condition of seismic strain which usually is relieved rapidly at first,
+but subsequently more slowly.
+
+The small shocks which follow an initial large disturbance are known as
+after-shocks. The first shock which in 1891 devastated central Japan was
+accompanied by the formation of a large fault, and the 3364 small shocks
+which succeeded this during the following two years are regarded as due
+to intermittent settlements of disjointed material. The decreasing
+frequency with which after-shocks occur may be represented by a curve.
+Dr F. Omori points out that the continuation of such a curve gives the
+means of determining the length of time which will probably elapse
+before the region to which it refers will return to the same seismic
+quiescence that it had prior to the initial disturbance.
+
+
+  Periodicity.
+
+The positive results that we have respecting the periodicity of
+earthquakes are but few. Generally earthquakes are somewhat more
+frequent during winter than during summer, and this applies to both the
+northern and southern hemispheres. The annual periodicity, which,
+however, does not show itself if only destructive earthquakes are
+considered, finds an explanation, according to Dr Knott, in the annual
+periodicity of long-continued stresses, as for example those due to the
+accumulation of snow and to barometric gradients. For certain earthquake
+regions there appears to be a distinct semi-annual period for which no
+satisfactory explanation has yet been adduced. Although the elaborate
+registers of Japan, which have enabled us to group earthquakes according
+to their respective origins and varying intensities, and to separate
+after-shocks from initial disturbances, have been subjected by Dr Knott
+to most careful analysis, with the object of discovering periodicities
+connected with the ebb and flow of the tides, the lunar day or lunar
+months, nothing of marked character has been found. Certainly there is
+slight evidence of a periodicity connected with the times of conjunction
+and opposition of the sun and moon, and a maximum frequency near the
+time of perigee, but the effect of lunar stresses is comparatively
+insignificant. Ordinary earthquakes, and especially after-shocks, show a
+diurnal period, but we cannot say that there are more earthquakes during
+the night than during the day.
+
+
+  Magnetic phenomena.
+
+Many experiments and investigations have been made to determine a
+possible relationship between earthquakes and electrical phenomena, but
+beyond drawing attention to the fact that luminous appearances may
+accompany the friction of moving masses of rock, and that a temporary
+current may be established in a line by the disturbance of an
+earth-plate, these inquiries have yielded but little of importance. The
+inquiries respecting a possible relationship between adjustments so
+frequently taking place within and beneath that region called the crust
+of the earth and magnetic phenomena are, however, of a more promising
+nature. We have seen that at or near the origin of earthquakes which for
+several hours disturb continents, and occasionally cause oceans to
+oscillate for longer periods, we sometimes have direct evidence of the
+bodily displacement of many cubic miles of material. When this material
+is volcanic it is almost invariably magnetic, and we perceive in its
+sudden rearrangement causes which should produce magnetic effects within
+an epifocal district. In Japan, where attention is being directed to
+phenomena of this description, not only have such effects been observed,
+but unusual magnetic disturbances have been noted prior to the
+occurrence of large earthquakes. These may, of course, be regarded as
+mere coincidences, but when we consider volcanic and seismic activities
+as evidences of physical and chemical changes, together with mechanical
+displacements of a magnetic magma, it is reasonable to suppose that they
+should have at least a local influence upon magnetic needles. Another
+form of disturbance to which magnetic needles are subjected is that
+which accompanies the passage of large earth-waves beneath certain
+observatories situated at great distances from earthquake origins. At
+Utrecht, Potsdam and Wilhelmshaven the magnetographs are frequently
+disturbed by seismic waves, whilst at many other European observatories
+such effects are absent or only barely appreciable. To explain these
+marked differences in the behaviour of magnetic needles at different
+stations we are at present only in a position to formulate hypotheses.
+They may be due to the fact that different needles have different
+periodic times of oscillation; it is possible that at one observatory
+the mechanical movements of the ground are much greater than at others;
+we may speculate on the existence of materials beneath and around
+various observatories which are different in their magnetic characters;
+and, lastly, we may picture a crust of varying thickness, which from
+time to time is caused to rise and fall upon a magnetic magma, the
+places nearest to this being the most disturbed.
+
+
+  Effects on the human mind.
+
+A subject to which but little attention has been directed is the effect
+which displays of seismic and volcanic activities have had upon the
+human mind. The effects are distinctly dual and opposite in character.
+In countries like England, where earthquakes are seldom experienced, the
+prevailing idea is that they are associated with all that is baneful.
+For certain earthquakes, which fortunately are less than 1% of those
+which are annually recorded, this is partially true. A disastrous shock
+may unnerve a whole community. Effects of this nature, however, differ
+in a marked manner with different nationalities. After the shock of
+1891, when Japan lost 9960 of its inhabitants, amongst the wounded
+indications of mental excitement were shown in spinal and other trouble.
+Notwithstanding the lightheartedness of this particular nation, it is
+difficult to imagine that the long series of seismic effects chronicled
+in Japanese history, which culminated in 1896 in the loss of 29,000
+lives by sea-waves, has been without some effect upon its mental and
+moral character. Several earthquakes are annually commemorated by
+special services at temples. In bygone times governments have recognized
+earthquakes as visitations of an angry deity, whom they have endeavoured
+to appease by repealing stringent laws and taxes. In other countries the
+sermons which have been preached to show that the tremblings of the
+world were visitations consequent on impiety, and the prayers which have
+been formulated to ward off disasters in the future, far exceed in
+number the earthquakes which gave rise to them. In 1755 many of the
+English clergy held the view that Lisbon was destroyed because its
+inhabitants were Catholics, whilst the survivors from that disaster
+attributed their misfortune to the fact that they had tolerated a few
+Protestant heretics in their midst. To avoid a recurrence of disaster
+certain of these were baptized by force. In the myths relating to
+underground monsters and personages that are said to be the cause of
+earthquakes we see the direct effects which exhibitions of seismic and
+volcanic activity have produced upon the imagination. The beliefs, or
+more properly, perhaps, the poetical fancies, thus engendered have
+exhibited themselves in various forms. Beneath Japan there is said to be
+a catfish, which in other countries is replaced by a mole, a hog, an
+elephant or other living creature, which when it is restless shakes the
+globe. The Kamchadales picture a subterranean deity called Tuil, who in
+Scandinavian mythology is represented by the evil genius Loki. We have
+only to think of the reference in the Decalogue forbidding the making of
+graven images of that which is in the earth beneath, to see in early
+Biblical history evidence of a subterranean mythology; and it seems
+probable that the same causes which led to the creation of Pluto, Vulcan
+and Poseidon gave rise to practices condemned by Moses.
+
+
+  Building to withstand earthquakes.
+
+Perhaps the greatest practical benefits derived from seismological
+investigations relate to important changes and new principles which have
+been introduced into the arts of the engineer and builder when
+constructing in earthquake countries. The new rules and formulae, rather
+than being theoretical deductions from hypotheses, are the outcome of
+observation and experiment. True measures of earthquake motion have been
+given to us by modern seismometers, with the result that seismic
+destructivity can be accurately expressed in mechanical units. From
+observation we now know the greatest acceleration and maximum velocity
+of an earth particle likely to be encountered; and these are measures of
+the destructivity. The engineer is therefore dealing with known forces,
+and he has to bear in mind that these are chiefly applied in a
+horizontal direction. A formula connecting the acceleration requisite to
+overturn bodies of different dimensions has been given. The acceleration
+which will fracture or shatter a column firmly fixed at its foundation
+to the moving earth may be expressed as follows:--
+
+      1  gFAB
+  a = -- ----,
+      6   fw
+
+where
+
+  a = the acceleration per sec. per sec.
+  F = the force of cohesion, or force per unit surface, which when
+        gradually applied produces fracture.
+  A = area of base fractured.
+  B = thickness of the column.
+  f = height of centre of gravity of column above the fractured base.
+  w = the weight of the portion broken off.
+
+With this formula and its derivatives we are enabled to state the height
+to which a wall, for example, may be built capable of resisting any
+assumed acceleration. Experience has shown that yielding first shows
+itself at the base of a pier, a wall or a building, and it is therefore
+clear that the lower portion of such structures should be of greater
+dimensions or stronger than that above. Piers having these increased
+dimensions below, and tapering upwards in a proper manner, so that every
+horizontal section is sufficiently strong to resist the effects of the
+inertia of its superstructure, are employed to carry railways in Japan.
+In that country cast-iron piers are things of the past, whilst piers of
+masonry, together with their foundations, no longer follow the rules of
+ordinary engineering practice.
+
+After flood, fire, earthquake, or when opportunity presents itself,
+changes are introduced in the construction of ordinary buildings. In a
+so-called earthquake-proof house, although externally it is similar to
+other dwellings, we find rafters running from the ridge pole to the
+floor sills, an exceedingly light roof, iron straps and sockets
+replacing mortices and tenons, and many other departures from ordinary
+rules. Masonry arches for bridges or arched openings in walls (unless
+protected by lintels), heavy gables, ornamental copings, cappings for
+chimneys, have by their repeated failure shown that they are undesirable
+features for construction in earthquake countries. As sites for
+buildings it is well to avoid soft ground, on which the movement is
+always greater than on hard ground. Excessive movement also takes place
+along the face of unsupported openings, and for this reason the edges of
+scarps, bluffs, cuttings and river-banks are localities to be avoided.
+In short, the rules and precautions which have to be recognized so as to
+avoid or mitigate the effects of earthquake movement are so numerous
+that students of engineering and architecture in Japan receive a special
+course of lectures on this subject. When it is remembered that a large
+earthquake may entail a loss of life greater than that which takes place
+in many wars, and that for the reconstruction of ordinary buildings,
+factories and public works an expenditure of several million pounds
+sterling is required, the importance of these studies cannot be
+overrated. Severe earthquakes are fortunately unknown in the British
+Isles, but we have simply to turn our eyes to earthquake-shaken colonies
+and lands in close commercial touch with Great Britain to realize the
+importance of mitigating such disasters as much as possible, and any
+endeavour to obviate the wholesale destruction of life should appeal to
+the civilized communities of the world.
+
+
+  Applications of seismometry.
+
+An unexpected application of seismometry has been to record the
+vibration of railway trains, bridges and steamships. An instrument of
+suitable construction will give records of the more or less violent
+jolting and vibratory movements of a train, and so localize
+irregularities due to changes in the character of ballast and sleepers,
+to variation in gauge, &c. An instrument placed on a locomotive throws
+considerable light upon the effects due to the methods of balancing the
+wheels, and by alterations in this respect a saving of fuel of from 1 to
+5 lb. of coal per mile per locomotive has sometimes been effected.
+
+By mapping the centres from which earthquakes originate off the coast of
+Japan, we have not only determined districts where geological activity
+is pronounced, but have placed before the cable engineer well-defined
+localities which it is advisable to avoid; and in the records of unfelt
+earthquakes which originate far from land similar information is being
+collected for the deeper parts of the oceans. Occasionally these records
+have almost immediately made clear the cause of a cable failure. From
+lack of such information in 1888, when the cables connecting Australia
+with the outer world were simultaneously broken, the sudden isolation
+was regarded as a possible operation of war, and the colonists called
+out their naval and military reserves. Records of earthquakes
+originating at great distances have also frequently enabled us to
+anticipate, to correct, to extend, or to disprove telegraphic accounts
+of the disasters. Whatever information a seismogram may give is certain,
+whilst the information gathered from telegrams may in the process of
+transit become exaggerated or minimized. Otherwise unaccountable
+disturbances in records from magnetographs, barographs and other
+instruments employed in observatories are frequently explained by
+reference to the traces yielded by seismometers. Perhaps the greatest
+triumph in seismological investigation has been the determination of the
+varying rates at which motion is propagated through the world. These
+measurements have already thrown new light upon its effective rigidity,
+and if we assume that the density of the earth increases uniformly from
+its surface towards its centre, so that its mean density is 5.5, then,
+according to Knott, the coefficient of elasticity which governs the
+transmission of preliminary tremors of an earthquake increases at a rate
+of nearly 1.2% per mile of descent.     (J. Mi.)
+
+  AUTHORITIES.--J. Milne, _Seismology_ (London, 1898), _Earthquakes_
+  (London, 1898), Bakerian Lecture, "Recent Advances in Seismology,"
+  _Proc. Roy. Soc._, 1906, 77, p. 365; J.A. Ewing, _Memoir on Earthquake
+  Measurement_ (Tokyo, 1883); C.E. Dutton, _Earthquakes in the Light of
+  the New Seismology_ (London, 1904); "The Charleston Earthquake of Aug.
+  31, 1886," Ninth Annual _Report_ of the United States Geological
+  Survey, 1889; W.H. Hobbs, _Earthquakes, an Introduction to Seismic
+  Geology_ (London, 1908), "The San Francisco Earthquake and Fire,
+  1906," _Bull. U.S. Geol. Surv._ No. 324; "The California Earthquake of
+  Ap. 18, 1906," _Rep. State Earthq. Com._ (Washington, D.C., 1908);
+  R.D. Oldham, "Report on the Great Earthquake of 12 June 1897," _Mem.
+  Geol. Surv. India_, xxix. 1899, "On the Propagation of Earthquake
+  Motion to great Distances," _Phil. Trans._, 1900, A, vol. 194, p. 135,
+  "The Constitution of the Interior of the Earth as revealed by
+  Earthquakes," _Quar. Jour. Geol. Soc._, 1906, 62, p. 456; 1907, 63, p.
+  344; C. Davison, _A Study of Recent Earthquakes_ (London, 1905); _The
+  Hereford Earthquake of December 17, 1896_ (Birmingham, 1899), "The
+  Investigation of Earthquakes," _Beitraege z. Geophysik_, Bd. ix., 1908,
+  p. 201, and papers on British earthquakes in _Quart. Jour. Geol.
+  Soc._; T.J.J. See, "The Cause of Earthquakes, Mountain Formation and
+  Kindred Phenomena connected with the Physics of the Earth," _Proc.
+  Amer. Phil. Soc._, 1906, 45, p. 273; F. Frech, "Erdbeben und
+  Gebirgsbau," _Petermann's Mitteilungen_, Bd. 53, 1907, p. 245 (with
+  maps); C.G. Knott, _The Physics of Earthquake Phenomena_ (Oxford,
+  1908); Comte F. de Montessus de Ballore, _Les Tremblements de terre:
+  geographie seismologique_ (Paris, 1906), _La Science seismologique_
+  (1907); _Transactions of the Seismological Society of Japan;
+  Seismological Journal_ (Yokohama); _Bollettino della Societa
+  Sismologica Italiana_ (Rome); _Reports of the British Association_,
+  containing the annual reports of the Committee for Seismological
+  Investigations; papers in the _Beitraege zur Geophysik_ and the
+  _Ergaenzungsbaende_.
+
+
+FOOTNOTES:
+
+  [1] The publications for 1880-1892 were termed the _Transactions of
+    the Seismological Society of Japan_, and for 1893-1895 the
+    _Seismological Journal of Japan_. The observations are now published
+    by the Earthquake Investigation Committee of Japan, and edited by F.
+    Omori, professor of seismology at the university of Tokyo.
+
+  [2] The chief Italian station is at Rocca di Papa near Rome. It is
+    equipped with delicate instruments designed by its director, Giovanni
+    Agamennone. The records since 1895 are published in the _Bollettino
+    della Societa Sismologica Italiana_, edited by Luigi Palazzo,
+    director of the Central Office for Meteorology and Geodynamics at
+    Rome.
+
+  [3] The chief Austrian publications are:--_Mittheilungen der
+    Erdbebencommission der k. Akad. der Wissen. in Wien_ (since 1897);
+    _Die Erdbebenwarte_ (1901-1907); and the "Neueste
+    Erdbebennachrichten, _Beilage der Monatsschrift Die Erdbebenwarte_."
+
+  [4] The "International Seismological Association" was founded at
+    Strassburg in 1903, and publishes the _Beitraege zur Geophysik_,
+    edited by George Gerland, director of the Strassburg station; the
+    papers are printed in several languages.
+
+  [5] The records of the British Association stations are published
+    (since 1896) in the _Reports_. Chile has a national earthquake
+    service (founded after the Valparaiso earthquake of August 1906)
+    directed by comte de Montessus de Ballore.
+
+
+
+
+EARTH-STAR (_Geaster_), in botany, a kind of puff-ball, with a distinct
+outer coat which, on separating from the inner, splits into several
+divisions, which become reflexed and spread like a star. The inner coat
+enveloping the spores is supported, like a ball, either with or without
+a stalk on the upper face of the star. The spores escape generally by
+means of a distinct aperture which appears in the top of the ball. There
+are several species in Britain found on the ground or on decaying
+leaves. They are rare or local, but more common in the south or
+south-east of England than in other parts of Britain.
+
+[Illustration: From Strasburger's _Lehrbuch der Botanik_, by permission
+of Gustav Fischer.
+
+_Geaster Granulosus_, nat. size.]
+
+
+
+
+EARTHWORM, the common name of a chaetopod worm found nearly all over the
+world. Linnaeus recognized only one species of earthworm and named it
+_Lumbricus terrestris_. There are now one thousand well-characterized
+species known from different parts of the world, and the number
+increases almost daily. The earthworms of England belong entirely to the
+three genera _Lumbricus_, _Allolobophora_ and _Allurus_, which are
+further subdivided by some systematists; and these genera form the
+prevalent earthworm fauna of the Palaearctic region and are also very
+numerous in the Nearctic region. Elsewhere they do not appear to be
+indigenous, but are replaced by the numerous other genera of the
+families enumerated in the article CHAETOPODA (q.v.). It is a remarkable
+fact that these genera, comprizing a separate family _Lumbricidae_, when
+introduced into tropical and other countries, thrive abundantly and oust
+the indigenous forms. In gatherings of earthworms from various
+extra-European countries it is always found that if the collections have
+been made in cultivated ground and near the coast the worms are of
+European species; farther inland the native forms are met with. Inasmuch
+as in every case the _Lumbricidae_ from non-European countries are
+identical with European species, since it has been shown that these
+animals are very readily introduced accidentally with plants, &c., and
+in view of the fact that they are impatient of sea water, it seems clear
+that the presence of these _Lumbricidae_ in other continents is due to
+accidental transportation. Most earthworms live in the soil, which they
+devour as they burrow through it. A few, like their allies the river
+worms (Limicolae), habitually frequent streams, lakes, &c. One genus, at
+any rate, viz. _Pontodrilus_, seeks an unusual environment, and is found
+in heaps of sea-weed cast up by the sea. The range of this genus is
+therefore naturally wider than that of other genera which are confined
+to land masses and cannot cross the sea by their own efforts. It might
+be inferred, therefore, and the inference is proved by facts, that truly
+oceanic islands have no indigenous fauna of earthworms, but are
+inhabited by forms which are identical with those of neighbouring
+continents, and doubtless, therefore, accidentally introduced.
+
+Like the leeches the earthworms produce cocoons which are a product of
+the glandular epithelium of the clitellum. In these cocoons are
+deposited the eggs together with a certain amount of albumen upon which
+the developing embryos feed. So far as is known, the production of
+cocoons is universal among earthworms and the remaining Oligochaeta of
+aquatic habit. The young leave the cocoon as fully formed earthworms in
+which, however, the genitalia are not fully developed. There is no free
+living larval stage. Out of a single cocoon emerge a varying number of
+young worms, the numbers being apparently characteristic of the species.
+The work of earthworms in aiding in the production of the subsoil and in
+levelling the surface was first studied by C. Darwin, and has since been
+investigated by others. This work is partly carried out beneath the
+surface and partly on the surface, upon which the worms wander at night
+and eject the swallowed and triturated earth; frequently castings of
+some height are formed of coiled ropes of agglutinated particles of
+mould. The indigenous species of Great Britain, about twenty in number,
+do not grow to a greater length than some 10 in.; but in several
+tropical countries there are species which grow to a length of from 3 to
+6 ft. Thus we have in Natal the gigantic _Microchaeta rappi_, in Ceylon
+_Megascolex coeruleus_, in Australia _Megascolides australis_, and an
+equally large form in South America.     (F. E. B.)
+
+
+
+
+EARWIG, an insect belonging to the _Forficulidae_, a family usually
+referred to the Orthoptera, but sometimes regarded as typifying a
+special order, to which the names Dermaptera, Dermatoptera and
+Euplexoptera have been given, in allusion to certain peculiarities in
+the structure of the wings in the species that possess them. The front
+wings are short and horny and when at rest meet without overlapping in
+the middle line, like the wing-cases of brachelytrous (cocktail)
+beetles. The hind wings, on the contrary, are for the most part
+membranous and, when extended, of large size; each consists of two
+portions, the distal of which, in virtue of the arrangement and jointing
+of its nervures, is capable of being both doubled up and folded fanwise
+beneath the proximal, which is partly horny when the wing is tucked away
+under the front wing-case of the same side. Apart from these
+characteristics, the most distinctive feature of earwigs is the presence
+at the end of the abdomen of a pair of pincers which are in reality
+modified appendages, known as cercopods, and represent the similar limbs
+of _Japyx_ and the caudal feelers of _Campodea_ and some other insects.
+
+The _Forficulidae_ are almost cosmopolitan; but the various species and
+genera differ from each other both in structure and size to a
+comparatively slight extent. The length and armature of the pincers and
+the presence or absence of wings are perhaps the most important features
+used by systematists in distinguishing the various kinds. Of particular
+zoological interest in this connexion is a Ceylonese genus _Dyscritina_,
+in which the cercopods are long, many-jointed and filiform during the
+early stages of growth, and only assume at the last moult the forcipate
+structure characteristic of the family. The best known earwig is the
+common European species, _Forficula auricularia_. This insect is
+gregarious and nocturnal. It hides by day under stones or the loosened
+bark of trees or in any crevice or hole sheltered from the light. At
+night it crawls about in search of food, which consists to a small
+extent of dead animal or vegetable matter, but principally, as gardeners
+are aware, of the petals and other parts of flowers of growing shoots
+and soft ripe fruit. During the winter earwigs lie dormant; but in the
+early months of the year females with their eggs may be found in the
+soil, frequently in deserted earthworm burrows. Maternal instincts are
+well developed, both the eggs, which number about fifty, and the young
+being carefully brooded and watched over by the parent. Except for the
+absence of wings, the young are miniature models of the adult. As growth
+proceeds the integument is periodically cast; and at the final moult the
+perfect winged insect appears. Males and females are like each other in
+size, but may be distinguished by the difference in the number of
+visible abdominal segments, the male having nine and the female seven.
+In the male, moreover, the pincers are caliper-like and toothed at the
+base, whereas in the female they are untoothed and only lightly curved
+at the tip. These differences suggest that the pincers aid in the
+pairing of the sexes. However that may be, they are known to be used in
+the folding of the wings; and their importance as weapons of defence is
+attested by the precision and effect with which they are wielded against
+assailants like ants.     (R. I. P.)
+
+
+
+
+EASEMENT (Fr. _aise_; O. Fr. _aisement_; Anglo-Lat. _aisiamentum_, a
+privilege or convenience), in English law, a species of "servitude" or
+limited right of use over land belonging to another. It is distinguished
+from _profits a prendre_--another species of servitude which involves a
+right to participate in the profits of the soil of another--since an
+easement confers merely a convenience (_aisiamentum_) to be exercised
+over the land of another (without any participation in the profits of
+it), i.e. a right to use the soil or produce of the soil in a way
+tending to the more convenient enjoyment of another piece of land. Thus
+a right of way is an easement, a right of common is a profit. An
+easement is distinguishable also from a licence, which, unless it is
+coupled with a grant, is personal to both grantor and grantee and is
+neither binding on the licensor, nor, in general, assignable by the
+licensee; while both the benefit and the burden of an easement are
+annexed to land (Gale on _Easements_, 8th ed. p. 2). With easements are
+sometimes classed certain closely allied "natural rights," such as a
+landowner's right to lateral support for his soil in its natural state,
+and a riparian owner's right to the natural flow of a stream.
+
+The essential features of an easement, in the strict sense of the term,
+are therefore these: (i.) It is an incorporeal right; a right to the use
+and enjoyment of land--not to the land itself; (ii.) it is imposed upon
+corporeal property; (iii.) it is a right without profit; (iv.) it
+requires for its constitution two distinct tenements--the "dominant
+tenement" which enjoys the right, and the "servient tenement" which
+submits to it. This last characteristic excludes from the category of
+easements the so-called "easements _in gross_," such as a right of way
+conferred by grant independently of the possession of any tenement by
+the grantee. The true easement is an "appendant" or "appurtenant" right,
+not a "right in gross."
+
+Further classifications of easements must be noted. They are divided
+into (a) _affirmative_ or _positive_, those which authorize the
+commission of an act by the dominant owner, e.g. rights of way, a right
+to draw water from a spring, rights of aqueduct, and _negative_, when
+the easement restricts the rights of the servient owner over his own
+property, e.g. prevents him from building on land so as to obstruct
+ancient lights (cf. also the right to the support of neighbouring soil);
+(b) _continuous_, of which the enjoyment may be continual without the
+interference of man, e.g. access to light, and _discontinuous_, where
+there must be a fresh act on each occasion of the exercise of the right,
+e.g. a right of way, or right to draw water; (c) _apparent_, where there
+are visible external signs of the exercise of the right, e.g. a right to
+dam up a watercourse, and _non-apparent_, where such signs are absent,
+e.g. a right to lateral support from land, a prohibition to build above
+a certain height.
+
+_Acquisition of Easements._--Easements may be acquired (a) by express
+grant, either by statute, or by deed _inter vivos_, or by will; (b) by
+an implied grant; (c) by express or implied reservation, e.g. by the
+owner of land in selling the fee (as to implied reservation, see Gale on
+_Easements_, 8th ed. pp. 137 et seq.); (d) by prescription, either at
+common law or under the Prescription Act 1832. An express grant, or
+express reservation, of an easement cannot be effected except by deed.
+An easement arises by implied grant where a man makes one part of his
+tenement dependent on another, or makes the parts mutually
+interdependent, and grants any such part with the dependence attaching
+to it to another person (Innes, _Law of Easements_, 7th ed. p. 10). For
+example, a man builds two houses, each of which by the plan of
+construction receives support from the other; this mutual right of
+support is a _quasi_-easement, of which on severance of the tenements
+the grantee of one will have the benefit; where the enjoyment of the
+severed tenement could not be had at all without such a right, it is
+said to be an "easement of necessity."
+
+Easements are acquired by prescription at common law by proof of
+"immemorial user" by the dominant owner and those through whom he
+claims. At one time it was thought that such proof must date back to the
+first year (1189) of Richard I. (see preamble to Prescription Act 1832).
+The ground, however, on which prescription was admitted as a means of
+acquiring easements was the fiction of a "lost grant." Long enjoyment of
+the right pointed to its having had a legal origin in a grant from the
+servient owner, and so any period of reasonably long use came to be
+accepted. A "lost grant" may be presumed to have been made (the question
+is one of fact) if 20 years' uninterrupted enjoyment is shown. To avoid
+the difficulties of proof of prescriptive right at common law, the
+Prescription Act 1832 established shorter periods of user. In the case
+of easements, other than light, the periods of prescription are 20 years
+for a claim that may be defeated, and 40 years for an indefeasible claim
+(s. 2). The right of access of light is dealt with under s. 3 (see
+ANCIENT LIGHTS). The enjoyment to become prescriptive must be open, i.e.
+of such a character that the owner of the tenement said to be servient
+has a reasonable opportunity of becoming aware of the adverse claim
+(_Union Lighterage Co._ v. _London Graving Dock Co._, 1902, 2 Ch. 557);
+and it must be enjoyed as of right (_Gardner_ v. _Hodgson's Kingston
+Brewery Co._, 1903, A.C. 229) as against the owner of the tenement
+affected (_Kilgour_ v. _Gaddes_, 1904, 1 K.B. 457). The periods of
+prescription are to be reckoned backwards from the time when some suit
+or matter involving the claim of the dominant owner has arisen (s. 4).
+Nothing is to be deemed an interruption unless the act of interruption
+has been submitted to, or acquiesced in, for a year (s. 4).
+
+Easements may be extinguished (i.) by express release--here an
+instrument under seal is necessary; (ii.) by "merger," i.e. where both
+tenements become the property of the same owner; (iii.) by abandonment
+through non-user. In the case of discontinuous easements, the shortest
+period of non-user may suffice if there is direct evidence of an
+intention to abandon.
+
+A word may be added here as to the right to air. It is an actionable
+nuisance to cause pollution of the air entering a dwelling-house. The
+owner of a dwelling-house may by prescription acquire a right to the
+passage of air through it by a defined channel; and the enjoyment
+without interruption of ventilation by means of air flowing in a
+definite channel, with the knowledge of the owner and occupier of the
+adjoining premises, creates a presumption of the grant of such an
+easement (see Gale on _Easements_, 8th ed. p. 338).
+
+In _Scots Law_ the term "easement" is unknown. Both the name "servitude"
+and the main species of servitudes existing in Roman law (q.v.) have
+been adopted. The classification of servitudes into positive and
+negative, &c., and the modes of their creation and extinction, are
+similar to those of English law. The statutory period of prescription is
+40 years (Scots Acts 1617, c. 12), or 20 years in the case of enjoyment
+under any _ex facie_ valid irredeemable title duly recorded in the
+appropriate register of sasines (Conveyancing [Scotland] Act 1874).
+There are certain servitudes special to Scots law, e.g. "thirlage," by
+which lands are "thirled" or bound to a particular mill, and the
+possessors obliged to grind their grain there, for payment of certain
+_multures_ (quantities of grain or meal, payable to the mill-owner) and
+_sequels_ (small quantities given to the mill servants) as the customary
+price of grinding. Statutory provision has been made for the commutation
+of these duties (Thirlage Act 1799), and they have now almost
+disappeared.
+
+The French Code Civil (Arts. 637 et seq.) and the other European codes
+(e.g. Belgium, arts. 637 et seq.; Holland, arts. 721 et seq.; Italy,
+arts. 531 et seq.; Spain, arts. 530 et seq.; Germany, arts. 1018 et
+seq.) closely follow Roman law. French law is in force in Mauritius, and
+has been followed in Quebec (Civil Code, arts. 499 et seq.) and St Lucia
+(Civil Code, arts. 449 et seq.). In India the law is regulated, on
+English lines, by the Easements Act 1882 (Act v. of 1882). The term
+"easements," however, in India includes _profits a prendre_. In the
+South African colonies the law of easements is based on the Roman Dutch
+law (see Maasdorp, _Institutes of Cape Law_, 1904; Bk. ii. p. 166 et
+seq.). In most of the other colonies the law of easements is similar to
+English law. In some, however, it has been provided by statute that
+rights to the access and use of light or water cannot be acquired by
+prescription: e.g. Victoria (Water Act 1890, No. 1156, s. 3), Ontario
+(Real Property Limitation Act, Revised Stats. Ontario, 1897; c. 133, s.
+36, light).
+
+In the _United States_ the law of easements is founded upon, and
+substantially identical with, English law. The English doctrine,
+however, as to acquisition of right of light and air by prescription is
+not accepted in most of the States.
+
+  AUTHORITIES.--_English Law_: Gale, _Law of Easements_ (8th ed.,
+  London, 1908); Goddard, _Law of Easements_ (6th ed., London, 1904);
+  Innes, _Digest of the Law of Easements_ (7th ed., London, 1903).
+  _Indian Law_: Peacock, _Easements in British India_ (Calcutta, 1904);
+  Hudson and Inman, _Law of Light and Air_ (2nd ed., London, 1905).
+  _Scots Law_: Erskine, _Principles of the Law of Scotland_ (20th ed.,
+  Edinburgh, 1903). _American Law_: Jones, _Law of Easements_ (New York,
+  1898); Bouvier, _Law Dict._ (Boston and London, 1897); _Ruling Cases_,
+  London and Boston, 1894-1901, tit. _Easement_ (American Notes).
+       (A. W. R.)
+
+
+
+
+EAST, ALFRED (1849-   ), English painter and etcher, was born at
+Kettering on the 15th of December 1849. One of the most prominent among
+modern English landscape painters, he received his art education first
+at the Glasgow School of Art and then in Paris at the Ecole des
+Beaux-Arts, and under Robert-Fleury and Bouguereau. His landscapes are
+remarkable for the lyrical use of colour and for the pleasing rhythm of
+line which is the result of careful selection and building up of the
+elements that constitute the scene. Based on keen observation of the
+colour of nature and on careful studies of the details, they are
+arranged with a rare and by no means obvious sense of balance and
+compositional beauty which summarily discards all disturbing accidents
+of nature. He also achieved distinction as an etcher, and published an
+instructive and useful volume on landscape painting (London, 1906). He
+began to exhibit at the Royal Academy in 1882, and was elected an
+associate. In 1906 he became president of the Royal Society of British
+Artists. Many of his works are to be found in the English provincial
+galleries; Manchester owns "The Silent Somme" and "Autumn"; Liverpool,
+"Gibraltar from Algeciras"; Leeds, "The Golden Valley"; Birmingham,
+"Hayle from Lelant"; Preston, "An Idyll of Spring"; and Hull, "Evening
+on the Cotswolds." His "Passing Storm" is at the Luxembourg; "The Nene
+Valley" at the Venice gallery; and "A Haunt of Ancient Peace" at the
+National gallery in Budapest. In 1903 he received the order of the Crown
+of Italy in connexion with his services to the Venice international
+exhibition; and he was made an honorary member of the Japanese Meiji
+Bijutsu Kai.
+
+
+
+
+EAST ANGLIA, one of the kingdoms into which Anglo-Saxon Britain was
+divided. Bede gives no information about its origin except that its
+earliest settlers were Angles. The kingdom of East Anglia comprised the
+two counties of Norfolk and Suffolk. With regard to the western boundary
+we have no accurate information, but it was probably formed by the fens
+of Cambridgeshire.
+
+This kingdom first appears in Bede's narrative early in the 7th century,
+when its power was at its height. Towards the end of the reign of
+AEthelberht, who died about 616, Raedwald of East Anglia, who had
+apparently spent some time at the court of Kent, began to win for
+himself the chief position among the Anglo-Saxon kings of his day. His
+position was assured, at least temporarily, in 617, when he decided to
+espouse the cause of the Northumbrian prince Edwin, then a fugitive at
+his court, and defeated AEthelfrith of Northumbria on the banks of the
+Idle, a tributary of the Trent, in Mercian territory. Raedwald had been
+converted to Christianity in Kent, but after his return home he
+relapsed, according to Bede, owing to the influence of his wife, and
+there were to be seen in the same building a Christian and a pagan
+altar. Bede states that Raedwald was the son of Tytili, the son of Wuffa,
+from whom the East Anglian royal family derived their name Wuffingas.
+According to the _Historia Brittonum_ Guffa (Wuffa) was the son of
+(Guecha) Wehha, who first ruled the East Angles in Britain. This would
+put the organization of the kingdom in the first or second quarter of
+the 6th century. Eorpwald, the son of Raedwald, was converted to
+Christianity by Edwin, but was soon afterwards slain by Ricberht (627 or
+628), whereupon the kingdom again became pagan for three years, when
+Sigeberht, the brother of Eorpwald, became king and founded a see for
+Felix at Dunwich. Sigeberht also founded a school in East Anglia, and on
+the arrival of an Irish missionary named Furseus he built him a
+monastery at _Cnobheresburg_, perhaps to be identified with Burgh
+Castle. Before 644, however, Sigeberht resigned the crown in favour of
+his brother Ecgric and retired to a monastery. Shortly afterwards both
+brothers were slain by Penda of Mercia in his invasion of East Anglia,
+and Anna became king. This king was an enthusiastic Christian, and
+converted Coenwalh, king of Wessex, who had fled to his court. Two of
+his daughters, Saethryth and AEthelberg, took the veil; while another,
+Sexburg, was married to Earconberht, king of Kent; and a fourth,
+AEthelthryth, after two marriages, with Tondberht of the South Gyrwe and
+Ecgfrith of Northumbria, became abbess of Ely. In 654 Anna was slain by
+Penda of Mercia, and was succeeded by his brother AEthelhere, who was
+killed in 655 at the Winwaed, fighting for the Mercian king against
+Oswio of Northumbria. In 673 Archbishop Theodore divided the East
+Anglian diocese into two, Elmham being the seat of the northern, Dunwich
+that of the southern bishop. A long blank follows in the history of this
+kingdom, until in 792 we find Offa of Mercia slaying AEthelberht, king of
+East Anglia, who is said to have been his son-in-law. East Anglia was
+subject to the supremacy of the Mercian kings until 825, when its people
+slew Beornwulf of Mercia, and with their king acknowledged Ecgberht
+(Egbert) of Wessex as their lord. In 870 Edmund, king of East Anglia,
+was killed by the Danes under I'varr and Ubbi, the sons of Ragnar
+Loethbrok.
+
+The following is a list of the kings of East Anglia of whom there is
+record:--Wehha; Wuffa; Raedwald, son of Tytili and grandson of Wuffa
+(reigning 617); Eorpwald, son of Raedwald (d. 627 or 628); Sigeberht,
+brother of Eorpwald; Ecgric, brother of Sigeberht (both slain before
+644); Anna, son of Ene and grandson of Tytili (d. 654); AEthelhere,
+brother of Anna (d. 655); AEthelwald, a third brother; Aldwulf (succ.
+663, d. 713), son of AEthelric and grandson of Ene; Elfwald, son of
+Aldwulf (d. 749); Hun Beonna and Alberht; AEthelberht (792); Edmund
+(870).
+
+After the death of Ragnar Loethbrok's sons East Anglia was occupied by the
+Danish king Guthrum, who made a treaty with Alfred settling their
+respective boundaries, probably about 880. Guthrum died in 890. A later
+king named Eohric took up the cause of AEthelwald, the son of AEthelred
+I., and was slain in the fight with the Kentish army at the Holm in 905.
+A war broke out with King Edward the Elder in 913; in 921 a king whose
+name is unknown was killed at the fall of Tempsford, and in the same
+year the Danes of East Anglia submitted to Edward the Elder. From this
+time, probably, East Anglia was governed by English earls, the most
+famous of whom were AEthelstan, surnamed Half-King (932-956) and his
+sons, AEthelwold (956-962), and AEthelwine, surnamed _Dei amicus_
+(962-992).
+
+  See Bede, _Hist. Eccl._ (ed. C. Plummer, Oxford. 1896), ii. 5, 15,
+  iii. 7, 8, 18-20, 22, iv. 3, 5, 23; _Saxon Chronicle_ (ed. Earle and
+  Plummer, Oxford, 1899), s. a. 823, 838, 866, 870, 880, 885, 890, 894,
+  905, 921; _Historia Brittonum_ (San-Marte, 1844), s. 59; H. Sweet,
+  _Oldest English Texts_, p. 171 (London, 1885).     (F. G. M. B.)
+
+
+
+
+EASTBOURNE, a municipal borough (1883) in the Eastbourne parliamentary
+division of Sussex, England, 61 m. S.S.E. of London by the London,
+Brighton & South Coast railway. Pop. (1891) 34,969; (1901) 43,344;
+(local census, 1909) 49,286. It is situated 3 m. N.E. of Beachy Head,
+the loftiest headland on the English Channel coast. It once consisted of
+three parts--the village of East Bourne, a mile inland; South Bourne,
+lying back from the shore; and Seahouses, facing the beach. The church
+of St Mary, the ancient parish church of East Bourne, is a fine
+transitional Norman building; and there are numerous modern churches and
+chapels. The principal buildings and institutions are the town hall and
+municipal buildings, the Princess Alice Memorial and other hospitals, a
+free library and, among many high-class schools, Eastbourne College for
+boys, founded in 1867. There is a fine pier with pavilion, and a marine
+parade nearly 3 m. in extent, arranged in terraced promenades.
+Devonshire Park of 13 acres is pleasantly laid out, and contains a
+pavilion and a theatre. The duke of Devonshire is the principal
+landowner. Golf links are laid out on the neighbouring downs. A Roman
+villa was formerly seen close to the shore, but it is not now visible.
+The corporation consists of a mayor, 8 aldermen and 24 councillors. In
+1910 the corporation promoted a bill in parliament to add the Hampden
+Park district in the parish of Willingdon to the borough and to make
+Eastbourne, with this extension, a county borough.
+
+
+
+
+EAST CHICAGO, a city of Lake county, Indiana, U.S.A., on Lake Michigan,
+about 19 m. S.E. of the business centre of Chicago. Pop. (1890) 1255;
+(1900) 3411 (1331 foreign-born); (1910) 19,098. It is served by several
+railways, including the Pennsylvania, the Wabash, the Chicago Terminal
+Transfer (whose shops are here), the Lake Shore & Michigan Southern, the
+Chicago, Indiana & Southern, and the Indiana Harbor railways. East
+Chicago covers an area whose greatest dimensions are 4 by 31/2 m. That
+part of the city along the lake, known as Indiana Harbor, dates from
+1901 and has grown very rapidly because of its position at the
+southernmost part of the Calumet District, and because of the meeting
+here of railway and lake commerce. A good harbour has been constructed,
+a new ship canal connecting the harbour with the Calumet river. East
+Chicago is industrially virtually a part of "Greater" Chicago; among its
+manufactures are iron and steel, cement, lumber, boilers, hay presses,
+chains, chemicals and foundry products. East Chicago was chartered as a
+city in 1893.
+
+
+
+
+EASTER, the annual festival observed throughout Christendom in
+commemoration of the resurrection of Jesus Christ. The name Easter (Ger.
+_Ostern_), like the names of the days of the week, is a survival from
+the old Teutonic mythology. According to Bede (_De Temp. Rat._ c. xv.)
+it is derived from _Eostre_, or _Ostara_, the Anglo-Saxon goddess of
+spring, to whom the month answering to our April, and called
+_Eostur-monath_, was dedicated. This month, Bede says, was the same as
+the _mensis paschalis_, "when the old festival was observed with the
+gladness of a new solemnity."
+
+The name of the festival in other languages (as Fr. _paques_; Ital.
+_pasqua_; Span. _pascua_; Dan. _paaske_; Dutch _paasch_; Welsh _pasg_)
+is derived from the Lat. _pascha_ and the Gr. [Greek: pascha]. These in
+turn come from the Chaldee or Aramaean form [Hebrew: pascha] _pascha'_,
+of the Hebrew name of the Passover festival [Hebrew: pesach] _pesach_,
+from [Hebrew: pasach] "he passed over," in memory of the great
+deliverance, when the destroying angel "passed over the houses, of the
+children of Israel in Egypt when he smote the Egyptians" (Exod. xii.
+27).
+
+An erroneous derivation of the word _pascha_ from the Greek [Greek:
+paschein], "to suffer," thus connected with the sufferings or passion of
+the Lord, is given by some of the Fathers of the Church, as Irenaeus,
+Tertullian and others, who were ignorant of Hebrew. St Augustine (_In
+Joann. Tract._ 55) notices this false etymology, shows how similarity of
+sound had led to it, and gives the correct derivation.
+
+There is no indication of the observance of the Easter festival in the
+New Testament, or in the writings of the apostolic Fathers. The sanctity
+of special times was an idea absent from the minds of the first
+Christians. "The whole of time is a festival unto Christians because of
+the excellency of the good things which have been given" is the comment
+of St Chrysostom on 1 Cor. v. 7, which has been erroneously supposed to
+refer to an apostolic observance of Easter. The ecclesiastical historian
+Socrates (_Hist. Eccl._ v. 22) states, with perfect truth, that neither
+the Lord nor his apostles enjoined the keeping of this or any other
+festival. He says: "The apostles had no thought of appointing festival
+days, but of promoting a life of blamelessness and piety"; and he
+attributes the observance of Easter by the church to the perpetuation of
+an old usage, "just as many other customs have been established."
+
+This is doubtless the true statement of the case. The first Christians
+continued to observe the Jewish festivals, though in a new spirit, as
+commemorations of events which those festivals had foreshadowed. Thus
+the Passover, with a new conception added to it of Christ as the true
+Paschal Lamb and the first fruits from the dead, continued to be
+observed, and became the Christian Easter.
+
+Although the observance of Easter was at a very early period the
+practice of the Christian church, a serious difference as to the day for
+its observance soon arose between the Christians of Jewish and those of
+Gentile descent, which led to a long and bitter controversy. The point
+at issue was when the Paschal fast was to be reckoned as ending. With
+the Jewish Christians, whose leading thought was the death of Christ as
+the Paschal Lamb, the fast ended at the same time as that of the Jews,
+on the fourteenth day of the moon at evening, and the Easter festival
+immediately followed, without regard to the day of the week. The Gentile
+Christians, on the other hand, unfettered by Jewish traditions,
+identified the first day of the week with the Resurrection, and kept the
+preceding Friday as the commemoration of the crucifixion, irrespective
+of the day of the month. With the one the observance of the day of the
+month, with the other the observance of the day of the week, was the
+guiding principle.
+
+Generally speaking, the Western churches kept Easter on the first day of
+the week, while the Eastern churches followed the Jewish rule, and kept
+Easter on the fourteenth day. St Polycarp, the disciple of St John the
+Evangelist and bishop of Smyrna, visited Rome in 159 to confer with
+Anicetus, the bishop of that see, on the subject; and urged the
+tradition, which he had received from the apostle, of observing the
+fourteenth day. Anicetus, however, declined to admit the Jewish custom
+in the churches under his jurisdiction, but readily communicated with
+Polycarp and those who followed it. About forty years later (197) the
+question was discussed in a very different spirit between Victor, bishop
+of Rome, and Polycrates, metropolitan of proconsular Asia. That province
+was the only portion of Christendom which still adhered to the Jewish
+usage, and Victor demanded that all should adopt the usage prevailing at
+Rome. This Polycrates firmly refused to agree to, and urged many weighty
+reasons to the contrary, whereupon Victor proceeded to excommunicate
+Polycrates and the Christians who continued the Eastern usage. He was,
+however, restrained from actually proceeding to enforce the decree of
+excommunication, owing to the remonstrance of Irenaeus and the bishops
+of Gaul. Peace was thus maintained, and the Asiatic churches retained
+their usage unmolested (Euseb. _H.E._ v. 23-25). We find the Jewish
+usage from time to time reasserting itself after this, but it never
+prevailed to any large extent.
+
+A final settlement of the dispute was one among the other reasons which
+led Constantine to summon the council of Nicaea in 325. At that time the
+Syrians and Antiochenes were the solitary champions of the observance of
+the fourteenth day. The decision of the council was unanimous that
+Easter was to be kept on Sunday, and on the same Sunday throughout the
+world, and "that none should hereafter follow the blindness of the
+Jews" (Socrates, _H.E._ i. 9). The correct date of the Easter festival
+was to be calculated at Alexandria, the home of astronomical science,
+and the bishop of that see was to announce it yearly to the churches
+under his jurisdiction, and also to the occupant of the Roman see, by
+whom it was to be communicated to the Western churches. The few who
+afterwards separated themselves from the unity of the church, and
+continued to keep the fourteenth day, were named _Quartodecimani_, and
+the dispute itself is known as the _Quarto-deciman_ controversy.
+Although measures had thus been taken to secure uniformity of
+observance, and to put an end to a controversy which had endangered
+Christian unity, a new difficulty had to be encountered owing to the
+absence of any authoritative rule by which the paschal moon was to be
+ascertained. The subject is a very difficult and complex one (see also
+CALENDAR). Briefly, it may be explained here that Easter day is the
+first Sunday after the full moon following the vernal equinox. This, of
+course, varies in different longitudes, while a further difficulty
+occurred in the attempt to fix the correct time of Easter by means of
+cycles of years, when the changes of the sun and moon more or less
+exactly repeat themselves. At first an eight years' cycle was adopted,
+but it was found to be faulty, then the Jewish cycle of 84 years was
+used, and remained in force at Rome till the year 457, when a more
+accurate calculation of a cycle of 532 years, invented by Victorius of
+Acquitaine, took its place. Ultimately a cycle of 19 years was accepted,
+and it is the use of this cycle which makes the Golden Number and Sunday
+Letter, explained in the preface to the Book of Common Prayer,
+necessary. Owing to this lack of decision as to the accurate finding of
+Easter, St Augustine tells us (_Epist._ 23) that in the year 387 the
+churches of Gaul kept Easter on the 21st of March, those of Italy on the
+18th of April, and those of Egypt on the 25th of April; and it appears
+from a letter of Leo the Great (_Epist._ 64, _ad Marcian._) that in 455
+there was a difference of eight days between the Roman and the
+Alexandrine Easter. Gregory of Tours relates that in 577 "there was a
+doubt about Easter. In Gaul we with many other cities kept Easter on the
+fourteenth calends of May, others, as the Spaniards, on the twelfth
+calends of April."
+
+The ancient British and Celtic churches followed the cycle of 84 years
+which they had originally received from Rome, and their stubborn refusal
+to abandon it caused much bitter controversy in the 8th century between
+their representatives and St Augustine of Canterbury and the Latin
+missionaries. These latter unfairly attempted to fix the stigma of the
+Quartodeciman observance on the British and Celtic churches, and they
+are even now sometimes ignorantly spoken of as having followed the
+Asiatic practice as to Easter. This, however, is quite erroneous. The
+British and Celtic churches always kept Easter according to the Nicene
+decree on a Sunday. The difference between them and the Roman Church, at
+this period, was that they still followed the 84 years' cycle in
+computing Easter, which had been abandoned at Rome for the more accurate
+cycle of 532 years. This difference of calculation led to Easter being
+observed on different Sundays, in certain years, in England, by the
+adherents of the two churches. Thus Bede records that in a certain year
+(which must have been 645, 647, 648 or 651) Queen Eanfleda, who had
+received her instruction from a Kentish priest of the Roman obedience,
+was fasting and keeping Palm Sunday, while her husband, Oswy, king of
+Northumbria, following the rule of the British church, was celebrating
+the Easter festival. This diversity of usage was ended, so far as the
+kingdom of Northumbria was concerned, by the council of Streaneshalch,
+or Whitby, in 654. To Archbishop Theodore is usually ascribed the credit
+of ending the difference in the rest of England in 669.
+
+The Gregorian correction of the calendar in 1582 has once more led to
+different days being observed. So far as Western Christendom is
+concerned the corrected calendar is now universally accepted, and Easter
+is kept on the same day, but it was not until 1752 that the Gregorian
+reformation of the calendar was adopted in Great Britain and Ireland.
+Jealousy of everything emanating from Rome still keeps the Eastern
+churches from correcting the calendar according to the Gregorian
+reformation, and thus their Easter usually falls before, or after, that
+of the Western churches, and only very rarely, as was the case in 1865,
+do the two coincide.
+
+Easter, as commemorating the central fact of the Christian religion, has
+always been regarded as the chief festival of the Christian year, and
+according to a regulation of Constantine it was to be the first day of
+the year. This reckoning of the year as beginning at Easter lingered in
+France till 1565, when, by an ordinance of Charles IX., the 1st of
+January finally took its place.
+
+Four different periods may be mentioned as connected with the observance
+of Easter, viz. (1) the preparatory fast of the forty days of Lent; (2)
+the fifteen days, beginning with the Sunday before and ending with the
+Sunday after Easter, during which the ceremonies of Holy Week and the
+services of the Octave of Easter were observed; this period, called by
+the French the _Quinzaine de Paques_, was specially observed in that
+country; (3) the Octave of Easter, during which the newly-baptized wore
+their white garments, which they laid aside on the Sunday after Easter,
+known as _Dominica in albis depositis_ from this custom; another name
+for this Sunday was _Pascha clausum_, or the close of Easter, and from a
+clipping of the word "close" the English name of "Low" Sunday is
+believed to be derived; (4) Eastertide proper, or the paschal season
+beginning at Easter and lasting till Whit Sunday, during the whole of
+which time the festival character of the Easter season was maintained in
+the services of the church.
+
+Many ecclesiastical ceremonies, growing up from early times, clustered
+round the celebration of the Easter festival. One of the most notable of
+these was the use of the paschal candle. This was a candle of very large
+dimensions, set in a candlestick big enough to hold it, which was
+usually placed on the north side, just below the first ascent to the
+high altar. It was kept alight during each service till Whitsuntide. The
+Paschal, as it was called at Durham cathedral, was one of the chief
+sights of that church before the Reformation. It was an elaborate
+construction of polished brass, and, contrary to the usual custom, seems
+to have been placed in the centre of the altar-step, long branches
+stretching out towards the four cardinal points, bearing smaller
+candles. The central stem of the candlestick was about 38 ft. high, and
+bore the paschal candle proper, and together they reached a combined
+height of about 70 ft., the candle being lighted from an opening above.
+Other paschal candles seem to have been of scarcely less size. At
+Lincoln, c. 1300, the candle was to weigh three stones of wax; at
+Salisbury in 1517 it was to be 36 ft. long; and at Westminster in 1558
+it weighed no less than 3 cwt. of wax. After Whitsuntide what remained
+was made into smaller candles for the funerals of the poor. In the
+ancient churches at Rome the paschal candlesticks were fixtures, but
+elsewhere they were usually movable, and were brought into the church
+and set up on the Thursday before Easter. At Winchester the paschal
+candlestick was of silver, and was the gift of Canute. Others of more or
+less importance are recorded as having been at Canterbury, Bury St
+Edmunds, Hereford and York. The burning of the paschal candle still
+forms part of the Easter ceremonial of the Roman Catholic Church (see
+LIGHTS, CEREMONIAL).
+
+The liturgical colour for Easter was everywhere white, as the sign of
+joy, light and purity, and the churches and altars were adorned with the
+best ornaments that each possessed. Flowers and shrubs no doubt in early
+times were also used for this purpose, but what evidence there is goes
+against the medieval use of such decorations, which are so popular at
+the present day.
+
+It is not the purpose of this article to enter on the wide subject of
+the popular observances, such as the giving and sending of Pasch or
+Easter eggs as presents. For such the reader may consult Brand's
+_Popular Antiquities_, Hone's _Every-Day Book_, and Chambers's _Book of
+Days_.
+
+  AUTHORITIES.--Bingham, _Antiquities of the Christian Church_; Bede,
+  _Ecclesiastical History of England_; Procter and Frere, _A New History
+  of the Book of Common Prayer_ (London, 1901); Surtees Society, _Rites
+  of Durham_, ed. J.T. Fowler (1903); De Morgan, _Companion to the
+  Almanac_ (1845); De Moleon, _Voyages liturgiques_ (Paris, 1718).
+       (T. M. F.)
+
+
+
+
+EASTER ISLAND (Rapanui, i.e. Great Rapa), an island in the eastern part
+of the South Pacific ocean, belonging to Chile (since 1888), in 27 deg. 8'
+S. and 109 deg. 28' W., 1400 m. E. of Pitcairn, and 2000 m. from the South
+American coast. It is roughly triangular in shape, with its hypotenuse
+12 m. long running north-east and south-west, and its three angles
+marked by three volcanic peaks, of which the north-eastern reaches 1768
+ft. of altitude. The area of the island is 45 sq. m. The coast has no
+good natural harbour, and landing is difficult. There is no lack of
+fertile soil, and the climate is moist enough to make up for the absence
+of running water. Formerly the island appears to have been wooded, but
+it now presents only a few bushes (_Edwardsia_, _Broussonetia_, &c.),
+ferns, grasses, sedges, &c. The natives grow bananas in the shelter of
+artificial pits, also sugar-canes and sweet potatoes, and keep a few
+goats and a large stock of domestic fowls, and a Tahitian commercial
+house breeds cattle and sheep on the island.
+
+It is doubtful whether Rapanui was discovered by Davis in 1686, though
+it is sometimes marked Davis Island on maps. Admiral Roggeveen reached
+it on Easter day 1722; in 1774 Captain Cook discovered it anew and
+called it Teapi or Waihu. It was subsequently visited by La Perouse
+(1776), Kotzebue (1816), &c. At the time of Roggeveen's discovery the
+island probably contained from 2000 to 3000 inhabitants of Polynesian
+race, who, according to their own tradition, came from Rapa Iti (Little
+Rapa) or Oparo, one of the Tubuai or Austral group. In 1863 a large
+proportion of the inhabitants were kidnapped by the Peruvians and
+transported to work at the guano diggings on the Chincha Islands. The
+next year a Jesuit mission from Tahiti reached the island and succeeded
+in the task of civilization. The natives, who number scarcely one
+hundred, are all Christians.
+
+Easter Island is famous for its wonderful archaeological remains. Here
+are found immense platforms built of large cut stones fitted together
+without cement. They are generally built upon headlands, and on the
+slope towards the sea. The walls on the seaside are, in some of the
+platforms, nearly 30 ft. high and from 200 to 300 ft. long, by about 30
+ft. wide. Some of the squared stones are as much as 6 ft. long. On the
+land side of the platforms there is a broad terrace with large stone
+pedestals upon which once stood colossal stone images carved somewhat
+into the shape of the human trunk. On some of the platforms there are
+upwards of a dozen images, now thrown from their pedestals and lying in
+all directions. Their usual height is from 14 to 16 ft., but the largest
+are 37 ft., while some are only about 4 ft. They are formed from a grey
+trachytic lava found at the east end of the island. The top of the heads
+of the images is cut flat to receive round crowns made of a reddish
+vesicular tuff found at a crater about 8 m. distant from the quarry
+where the images were cut. A number of these crowns still lie at the
+crater apparently ready for removal, some of the largest being over 10
+ft. in diameter. In the atlas illustrating the voyage of La Perouse a
+plan of the island is given, with the position of several of the
+platforms. Two of the images are also represented in a plate. One
+statue, 8 ft. in height and weighing 4 tons, was brought to England, and
+is now in the British Museum. In one part of the island are the remains
+of stone houses nearly 100 ft. long by about 20 ft. wide. These are
+built in courses of large flat stones fitted together without cement,
+the walls being about 5 ft. thick and over 5 ft. high. They are lined on
+the inside with upright slabs, on which are painted geometrical figures
+and representations of animals. The roofs are formed by placing slabs so
+that each course overlaps the lower one until the opening becomes about
+5 ft. wide, when it is covered with flat slabs reaching from one side to
+the other. The lava rocks near the houses are carved into the
+resemblance of various animals and human faces, forming, probably, a
+kind of picture writing. Wooden tablets covered with various signs and
+figures have also been found. The only ancient implement discovered on
+the island is a kind of stone chisel, but it seems impossible that such
+large and numerous works could have been executed with such a tool. The
+present inhabitants of Easter Island know nothing of the construction of
+these remarkable works; and the entire subject of their existence in
+this small and remote island is a mystery.
+
+
+
+
+EASTERN BENGAL AND ASSAM, a province of British India, which was
+constituted out of Assam and the eastern portion of Bengal on the 16th
+of October 1905. Area 111,569 sq. m.; pop. (1901) 30,961,459. It is
+situated between 20 deg. 45' and 28 deg. 17' N., and between 87 deg. 48' and 97 deg. 5'
+E. The province, as thus reconstituted, consists of the Bengal districts
+of Dacca, Mymensingh, Faridpur, Backergunje, Tippera, Noakhali,
+Chittagong, Chittagong Hill Tracts, Rajshahi, Dinajpur, Jalpaiguri,
+Rangpur, Bogra, Pabna, Malda, and the native states of Kuch Behar and
+Hill Tippera; and the whole of the former area of Assam consisting of
+the districts of Goalpara, Kamrup, Darrang, Nowgong, Sibsagar,
+Lakhimpur, Sylhet, Cachar, Garo Hills, Khasi and Jaintia Hills, Naga
+Hills and Lushai Hills. It is bounded on the N. by Bhutan, on the W. by
+Burma, on the S. by Burma and the Bay of Bengal, and on the E. by
+Bengal. The line of demarcation between Bengal and the new province
+begins at the frontier of Bhutan, east of Darjeeling, runs south-west to
+Sahibganj on the Ganges and thence follows the course of the Ganges down
+to the deltaic branch, called the Haringhata, which leaves the main
+stream above Goalanda, and the course of the latter, which runs south
+into the Bay of Bengal. The capital of the province is Dacca, and its
+chief port is Chittagong.
+
+The Bengal districts which were transferred to Eastern Bengal and Assam
+comprised northern and eastern Bengal, the most prosperous and least
+overcrowded portion of Bengal. The land there is less densely populated,
+wages are higher and food cheaper, and the rainfall more copious and
+more regular, while the staple crops of jute, tobacco and rice command a
+higher price relative to the rent of the land than in Behar or other
+parts of Bengal. The population are largely Mahommedans and of a more
+virile stock than the Bengali proper. Northern Bengal corresponds almost
+exactly with the Rajshahi division and lies within the boundaries of the
+Ganges and Brahmaputra rivers. It contains much high land of a stiff red
+clay, with an undulating surface covered for the most part with scrub
+jungle. The inhabitants are Indo-Chinese, not Indo-Aryans as in Bengal
+proper, and are Mahommedan by religion instead of Hindu. Eastern Bengal
+consists of the Dacca and Chittagong divisions which are mainly Bengali
+in race and Hindu in religion. For the Assamese districts see ASSAM. The
+province as a whole contains 18,036,688 Mahommedans and 12,036,538
+Hindus. In language 27,272,895 of the inhabitants speak Bengali,
+1,349,784 speak Assamese, and the remainder Hindi and various hill
+dialects, Manipuri, Bodo, Khasi and Garo. The administration is in the
+hands of a lieutenant-governor, assisted by a legislative council of
+fifteen members. Under him are five commissioners, and financial matters
+are regulated by a board of revenue consisting of two members.
+
+The constitution of the new province arose out of the fact that Bengal
+had grown too unwieldy for the administration of a single
+lieutenant-governor. In 1868 Sir Stafford Northcote drew attention to
+the greatly augmented demands that the outlying portions of Bengal made
+on the time and labour of the government. At that time the population of
+the province was between 40 and 50 millions, and the question was left
+in abeyance until 1903, when the population had risen to 781/2 millions.
+In the meantime the importance of rendering Assam a self-contained and
+independent administration with a service of its own, and of providing
+for its future commercial expansion, had arisen. These two
+considerations led Lord Curzon to propose that Bengal should be lopped
+of territory both on its eastern and western borders, and that all the
+districts east of the Brahmaputra should be constituted into a separate
+province. This proposal was bitterly opposed by the Hindus of Bengal on
+the ground that it would destroy the unity of the Bengali race; and
+their agitation was associated with the _Swadeshi_ (own country)
+movement for the boycott of British goods.
+
+After the constitution of the province in October 1905, the agitation in
+Eastern Bengal increased. Public meetings of protest were held,
+vernacular broadsheets containing scandalous attacks on the British
+authorities were circulated, schoolboys and others were organized and
+drilled as so-called "national volunteers," and employed as pickets to
+prevent the sale of British goods. Such was the state of things when Sir
+J. Bampfylde Fuller entered on his office as first lieutenant-governor
+of Eastern Bengal in January 1906. His reception was ominous.
+Representative bodies that were dominated by Hindus refused to vote the
+usual addresses of welcome, and non-official Hindus abstained from
+paying the customary calls. There were, however, no further overt signs
+of objection to the lieutenant-governor personally, and after a month or
+two--in spite of, or perhaps because of, his efforts to restrain
+sedition and to keep discipline in the schools--there was a decided
+change in the attitude of Hindu opinion. At Dacca, in July, for
+instance, the reception at Government House was attended by large
+numbers of Bengali gentlemen, who assured the lieutenant-governor that
+"the trouble was nearly ended." The agitation was, in fact, largely
+artificial, the work of Calcutta lawyers, journalists and schoolmasters;
+the mass of the people, naturally law-abiding, was unmoved by it so long
+as the government showed a firm hand; while the Mussulmans, who formed a
+large proportion of the whole, saw in the maintenance of the partition
+and of the prestige of the British government the guarantees of their
+own security.
+
+All seemed to be going well when an unfortunate difference of opinion
+occurred between the lieutenant-governor and the central government,
+resulting in the resignation of Sir Bampfylde Fuller (August 1906) and
+in ulterior consequences destined to be of far-reaching import. The
+facts are briefly as follows. Acting on a report of Dr P. Chatterji,
+inspector of schools, dated January 2, 1906, the lieutenant-governor, on
+the 10th of February, addressed a letter to the registrar of Calcutta
+University recommending that the privilege of affiliation to the
+university should be withdrawn from the Banwarilal and Victoria high
+schools at Sirajganj in Pabna, as a punishment for the seditious conduct
+of both pupils and teachers. Apart from numerous cases of illegal
+interference with trade and of disorder in the streets reported against
+the students, two specific outrages of a serious character were
+instanced as having occurred on the 15th of November: the raiding of a
+cart laden with English cloth belonging to Marwari traders, and a
+cowardly assault by some 40 or 50 lads on the English manager of the
+Bank of Bengal. These outrages "were not the result of thoughtlessness
+or sudden excitement, but were the outcome of a regularly organized
+scheme, set on foot and guided by the masters of these schools, for
+employing the students in enforcing a boycott." All attempts to discover
+and punish the offenders had been frustrated by the refusal of the
+school authorities to take action, and in the opinion of the
+lieutenant-governor the only course open was to apply the remedy
+suggested in the circular letter addressed to magistrates and collectors
+(October 10, 1905) by Mr R.W. Carlyle, the officiating chief secretary
+to the government of Bengal, directing them, in the event of students
+taking any part in political agitation, boycotting and the like, to
+inform the heads of schools or colleges concerned that, unless they
+prevented such action being taken by the boys attending their
+institutions, their grant-in-aid and the privilege of competing for
+scholarships and of receiving scholarship-holders would be withdrawn,
+and that the university would be asked to disaffiliate their
+institutions.
+
+The reply, dated July 5th, from the secretary in the home department of
+the government of India, was--to use Sir Bampfylde's own later
+expression--to throw him over. It was likely that a difference of
+opinion in the syndicate of the university would arise as to the degree
+of culpability that attached to the proprietors of the schools; in the
+event of the syndicate taking any "punitive action," the matter was
+certain to be raised in the senate, and would lead to an acrimonious
+public discussion, in which the partition of Bengal and the
+administration of the new province would be violently attacked; and in
+the actual state of public opinion in Bengal it seemed to the government
+of India highly inexpedient that such a debate should take place.
+"Collective punishment," too, "would be liable to be misconstrued in
+England," and the government preferred to rely on the gradual effect of
+the new university regulations, which aimed "at discouraging the
+participation of students in political movements by enforcing the
+responsibility of masters and the managing committees of schools for
+maintaining discipline."
+
+On receipt of this communication Sir Bampfylde Fuller at once tendered
+his resignation to the viceroy (July 15). He pointed out that to
+withdraw from the position taken up would be "concession, not in the
+interests of education, but to those people in Calcutta who have been
+striving to render my government impossible, in order to discredit the
+partition"; that previous concessions had had merely provocative
+effects, and that were he to give way in this matter his authority would
+be so weakened that he would be unable to maintain order in the country.
+On the 3rd of August, after some days of deliberation, the viceroy
+telegraphed saying that he was "unable to reconsider the orders sent,"
+and accepting Sir Bampfylde's resignation. By the Anglo-Indian press the
+news was received with something like consternation, the _Times of
+India_ describing the resignation as one of the gravest blunders ever
+committed in the history of British rule in India, and as a direct
+incentive to the forces of disquiet, disturbance and unrest. Equally
+emphatic was the verdict of the Mussulman community forming two-thirds
+of the population of Eastern Bengal. On the 7th of August, the day of
+Sir Bampfylde Fuller's departure from Dacca, a mass-meeting of 30,000
+Mahommedans was held, which placed on record their disapproval of a
+system of government "which maintains no continuity of policy," and
+expressed its feeling that the lowering of British prestige must
+"alienate the sympathy of a numerically important and loyal section of
+His Majesty's subjects"; and many meetings of Mussulmans subsequently
+passed resolutions to the same general effect. The _Akhbar-i-Islam_, the
+organ of Bombay Mussulman opinion, deplored the "unwise step" taken by
+the government, and ascribed it to Lord Minto's fear of the Babu press,
+a display of weakness of which the Babus would not be slow to take
+advantage.
+
+This latter prophecy was not slow in fulfilling itself. So early as the
+8th of August Calcutta was the scene of several large demonstrations at
+which the Swadeshi vow was renewed, and at which resolutions were passed
+declining to accept the partition as a settled fact, and resolving on
+the continuance of the agitation. The tone of the Babu press was openly
+exultant: "We have read the familiar story of the Russian traveller and
+the wolves," said a leading Indian newspaper in Calcutta. "The British
+government follows a similar policy. First the little babies were
+offered up in the shape of the _Bande Mataram_ circular and the Carlyle
+circular. Now a bigger boy has gone in the person of our own Joseph.
+Courage, therefore, O wolves! Press on and the horse will soon be yours
+to devour! Afterwards the traveller himself will alone be left."[1] The
+task before the new lieutenant-governor of Eastern Bengal, the Hon. L.
+Hare, was obviously no easy one. The encouragement given to sedition by
+the weakness of the government in this case was shown by later events in
+Bengal and elsewhere (see INDIA: _History, ad fin._).
+
+For the early history of the various portions of the province see BENGAL
+and ASSAM.
+
+  See Sir James Bourdillon, _The Partition of Bengal_ (Society of Arts,
+  1905); official blue-books on _The Reconstitution of the Provinces of
+  Bengal and Assam_ (Cd. 2658 and 2746), and _Resignation of Sir J.
+  Bampfylde Fuller_, lieutenant-governor, &c. (Cd. 3242). A long letter
+  from Sir J.B. Fuller, headed _J'accuse_, attacking the general policy
+  of the Indian government in regard to the seditious propaganda,
+  appeared in _The Times_ of June 6, 1908.
+
+
+FOOTNOTE:
+
+  [1] Quoted by Mr F.S.P. Lely in _The Times_ of November 22, 1906.
+
+
+
+
+EASTERN QUESTION, THE, the expression used in diplomacy from about the
+time of the congress of Verona (1822) to comprehend the international
+problems involved in the decay of the Turkish empire and its supposed
+impending dissolution. The essential questions that are involved are so
+old that historians commonly speak of the "Eastern Question" in
+reference to events that happened long before the actual phrase was
+coined. But, wherever used, it is always the Turkish Question, the
+generic term in which subsidiary issues, e.g. the Greek, Armenian or
+Macedonian questions, are embraced. That a phrase of so wide and loose a
+nature should have been stereotyped in so narrow a sense is simply the
+outcome of the conditions under which it was invented. To the European
+diplomatists of the first half of the 19th century the Ottoman empire
+was still the only East with which they were collectively brought into
+contact. The rivalry of Great Britain and Russia in Persia had not yet
+raised the question of the Middle East; still less any ambitions of
+Germany in the Euphrates valley. The immense and incalculable problems
+involved in the rise of Japan, the awakening of China, and their
+relations to the European powers and to America--known as the Far
+Eastern Question--are comparatively but affairs of yesterday.
+
+The Eastern Question, though its roots are set far back in history--in
+the ancient contest between the political and intellectual ideals of
+Greece and Asia, and in the perennial rivalry of the powers for the
+control of the great trade routes to the East--dates in its modern sense
+from the treaty of Kuchuk Kainarji in 1774, which marked the definitive
+establishment of Russia as a Black Sea power and formed the basis of her
+special claims to interfere in the affairs of the Ottoman empire. The
+compact between Napoleon and the emperor Alexander I. at Tilsit (1807)
+marked a new phase, which culminated in 1812 in the treaty of Bucharest,
+in which Russia definitely appeared as the protector of the Christian
+nationalities subject to the Ottoman sultan.
+
+The attitude of the various powers in the Eastern Question was now
+defined. Russia, apart from her desire to protect the Orthodox
+nationalities subject to the Ottoman power, aimed at owning or
+controlling the straits by which alone she could find an outlet to the
+Mediterranean and the ocean beyond. Austria, once the champion of Europe
+against the Turk, saw in the Russian advance on the Danube a greater
+peril than any to be feared from the moribund Ottoman power, and made
+the maintenance of the integrity of Turkey a prime object of her policy.
+She was thus brought into line with Great Britain, whose traditional
+friendship with Turkey was strengthened by the rise of a new power whose
+rapid advance threatened the stability of British rule in India. But
+though Austria, Great Britain and presently France, were all equally
+interested in maintaining the Ottoman empire, the failure of the
+congress of Vienna in 1815 to take action in the matter of a guarantee
+of Turkey, and the exclusion of the Sultan from the Holy Alliance,
+seemed to endorse the claim of Russia to regard the Eastern Question as
+"her domestic concern" in which "Europe" had no right to interfere. The
+revolt of the Greeks (1821) put this claim to the test; by the treaty of
+Adrianople (1829) Russia stipulated for their autonomy as part of the
+price of peace, but the powers assembled in conference at London refused
+to recognize this settlement, and the establishment of Greece as an
+independent kingdom (1832) was really aimed at the pretensions and the
+influence of Russia. These reached their high-water mark in the treaty
+of Unkiar Skelessi (July 8th, 1832). It was no longer a question of the
+partition of Turkey or of a Russian conquest of Constantinople, but of
+the deliberate degradation by Russia of the Ottoman empire into a weak
+state wholly dependent upon herself. The ten years' crisis (1831-1841)
+evoked by the revolt of Mehemet Ali, pasha of Egypt, thus resolved
+itself into a diplomatic struggle between Russia and the other powers to
+maintain or to recover influence at Constantinople. The Russian
+experiment of maintaining the integrity of Turkey while practically
+treating her as a vassal state, ended with the compromise of 1841; and
+the emperor Nicholas I. reverted to the older idea of expelling the
+Turks from Europe. The Eastern Question, however, slumbered until, in
+1851, the matter of the Holy Places was raised by Napoleon III.,
+involving the whole question of the influence in Ottoman affairs of
+France under the capitulations of 1740 and of Russia under the treaty of
+1774. The Crimean War followed and in 1856 the treaty of Paris, by which
+the powers hoped to stem the tide of Russian advance and establish the
+integrity of a reformed Ottoman state. Turkey was now for the first
+time solemnly admitted to the European concert. The next critical phase
+was opened in 1871, when Russia took advantage of the collapse of France
+to denounce the Black Sea clauses of the treaty of 1856. The renewal of
+an aggressive policy thus announced to the world soon produced a new
+crisis in the Eastern Question, which had meanwhile become complicated
+by the growth of Pan-Slav ideals in eastern Europe. In 1875 a rising in
+Herzegovina gave evidence of a state of feeling in the Balkan peninsula
+which called for the intervention of Europe, if a disastrous war were to
+be prevented. But this intervention, embodied in the "Andrassy Note"
+(December 1875) and the Berlin memorandum (May 1876), met with the
+stubborn opposition of Turkey, where the "young Turks" were beginning to
+oppose a Pan-Islamic to the Pan-Slav ideal. The Russo-Turkish War of
+1877-78 followed, concluded by the treaty of San Stefano, the terms of
+which were modified in Turkey's favour by the congress of Berlin (1878),
+which marks the beginning of the later phase of the Eastern Question.
+Between Russia and Turkey it interposed, in effect, a barrier of
+independent (Rumania, Servia) and quasi-independent (Bulgaria) states,
+erected with the counsel and consent of collective Europe. It thus,
+while ostensibly weakening, actually tended to strengthen the Ottoman
+power of resistance.
+
+The period following the treaty of Berlin is coincident with the reign
+of Sultan Abd-ul-Hamid II. The international position of the Ottoman
+empire was strengthened by the able, if Machiavellian, statecraft of the
+sultan; while the danger of disruption from within was lessened by the
+more effective central control made possible by railways, telegraphs,
+and the other mechanical improvements borrowed from western
+civilization. With the spread of the Pan-Islamic movement, moreover, the
+undefined authority of the sultan as caliph of Islam received a fresh
+importance even in countries beyond the borders of the Ottoman empire,
+while in countries formerly, or nominally still, subject to it, it
+caused, and promised to cause, incalculable trouble.
+
+The Eastern Question thus developed, in the latter years of the 19th
+century, from that of the problems raised by the impending break-up of a
+moribund empire, into the even more complex question of how to deal with
+an empire which showed vigorous evidence of life, but of a type of life
+which, though on all sides in close touch with modern European
+civilization, was incapable of being brought into harmony with it. The
+belief in the imminent collapse of the Ottoman dominion was weakened
+almost to extinction; so was the belief, which inspired the treaty of
+1856, in the capacity of Turkey to reform and develop itself on European
+lines. But the Ottoman empire remained, the mistress of vast undeveloped
+wealth. The remaining phase of the Eastern Question, if we except the
+concerted efforts to impose good government on Macedonia in the
+interests of European peace, or the side issues in Egypt and Arabia, was
+the rivalry of the progressive nations for the right to exploit this
+wealth. In this rivalry Germany, whose interest in Turkey even so late
+as the congress of Berlin had been wholly subordinate, took a leading
+part, unhampered by the traditional policies or the humanitarian
+considerations by which the interests of the older powers were
+prejudiced. The motives of German intervention in the Eastern Question
+were ostensibly commercial; but the Bagdad railway concession,
+postulating for its ultimate success the control of the trade route by
+way of the Euphrates valley, involved political issues of the highest
+moment and opened up a new and perilous phase of the question of the
+Middle East.
+
+This was the position when in 1908 an entirely new situation was created
+by the Turkish revolution. As the result of the patient and masterly
+organization of the "young Turks," combined with the universal
+discontent with the rule of the sultan and the palace _camarilla_, the
+impossible seemed to be achieved, and the heterogeneous elements
+composing the Ottoman empire to be united in the desire to establish a
+unified state on the constitutional model of the West. The result on the
+international situation was profound. Great Britain hastened to re-knit
+the bonds of her ancient friendship with Turkey; the powers, without
+exception, professed their sympathy with the new regime. The
+establishment of a united Turkey on a constitutional and nationalist
+basis was, however, not slow in producing a fresh complication in the
+Eastern Question. Sooner or later the issue was sure to be raised of the
+status of those countries, still nominally part of the Ottoman empire,
+but in effect independent, like Bulgaria, or subject to another state,
+like Bosnia and Herzegovina. The cutting of the Gordian knot by
+Austria's annexation of Bosnia and Herzegovina, and by the proclamation
+of the independence of Bulgaria, and of Prince Ferdinand's assumption of
+the old title of tsar (king), threatened to raise the Eastern Question
+once more in its acutest form. The international concert defined in the
+treaty of Berlin had been rudely shaken, if not destroyed; the
+denunciation by Austria, without consulting her co-signatories, of the
+clauses of the treaty affecting herself seemed to invalidate all the
+rest; and in the absence of the restraining force of a united concert of
+the great powers, free play seemed likely once more to be given to the
+rival ambitions of the Balkan nationalities, the situation being
+complicated by the necessity for the dominant party in the renovated
+Turkish state to maintain its prestige. During the anxious months that
+followed the Austrian _coup_, the efforts of diplomacy were directed to
+calming the excitement of Servians, Montenegrins and the Young Turks,
+and to considering a European conference in which the _fait accompli_
+should be regularized in accordance with the accepted canons of
+international law. The long delay in announcing the assembly of the
+conference proved the extreme difficulty of arriving at any satisfactory
+basis of settlement; and though the efforts of the powers succeeded in
+salving the wounded pride of the Turks, and restraining the impetuosity
+of the Serbs and Montenegrins, warlike preparations on the part of
+Austria continued during the winter of 1908-1909, being justified by the
+agitation in Servia, Montenegro and the annexed provinces. It was not
+till April 1909 (see EUROPE: ad fin.) that the crisis was ended, through
+the effectual backing given by Germany to Austria; and Russia, followed
+by England and France, gave way and assented to what had been done.
+
+  See TURKEY: _History_, where cross-references to the articles on the
+  various phases of the Eastern Question will be found, together with a
+  bibliography. See also E. Driault, _La Question d'orient depuis son
+  origine_ (Paris, 1898), a comprehensive sketch of the whole subject,
+  including the Middle and Far East.     (W. A. P.)
+
+
+
+
+EAST GRINSTEAD, a market town in the East Grinstead parliamentary
+division of Sussex, England, 30 m. S. by E. from London by the London,
+Brighton & South Coast railway. Pop. of urban district (1901) 6094. St
+Swithin's church contains, among numerous ancient memorials, one of the
+iron memorial slabs (1507) peculiar to certain churches of Sussex, and
+recalling the period when iron was extensively worked in the district.
+There may be noticed Sackville College (an almshouse founded in 1608),
+and St Margaret's home and orphanage, founded by the Rev. John Mason
+Neale (1818-1866), warden of Sackville College. Brewing and brick and
+tile making are carried on. In the vicinity (near Forest Row station) is
+the golf course of the Royal Ashdown Forest Golf Club.
+
+The hundred of East Grinstead (Grenestede, Estgrensted) was in the
+possession of the count of Mortain in 1086, but no mention of a vill or
+manor of East Grinstead is made in the Domesday Survey. In the reign of
+Henry III. the hundred was part of the honour of Aquila, then in the
+king's hands. The honour was granted by him to Peter of Savoy, through
+whom it passed to his niece Queen Eleanor. In the next reign the king's
+mother held the borough of East Grinstead as parcel of the honour of
+Aquila. East Grinstead was included in a grant by Edward III. to John of
+Gaunt, duke of Lancaster, and it remained part of the duchy of Lancaster
+until James I. granted the borough to Sir George Rivers, through whom it
+was obtained by the Sackvilles, earls of Dorset. East Grinstead was a
+borough by prescription. In the 16th century it was governed by an
+alderman, bailiff and constable. It returned two members to parliament
+from 1307 until 1832, but was disenfranchised by the Reform Act. In 1285
+the king ordered that his market at Grenestede should be held on
+Saturday instead of Sunday, and in 1516 the inhabitants of the town were
+granted a market each week on Saturday and a fair every year on the eve
+of St Andrew and two days following. Charles I. granted the earl of
+Dorset a market on Thursday instead of the Saturday market, and fairs on
+the 16th of April and the 26th of September every year. Thursday is
+still the market-day, and cattle-fairs are now held on the 21st of April
+and the 11th of December.
+
+
+
+
+EAST HAM, a municipal borough in the southern parliamentary division of
+Essex, England, contiguous to West Ham, and thus forming geographically
+part of the eastward extension of London. Pop. (1901) 96,018. Its modern
+growth has been very rapid, the population being in the main of the
+artisan class. There are some chemical and other factories. The ancient
+parish church of St Mary Magdalen retains Norman work in the chancel,
+which terminates in an eastern apse. There is a monument for Edmund
+Neville who claimed the earldom of Westmorland in the 17th century, and
+William Stukeley, the antiquary, was buried in the churchyard. East Ham
+was incorporated in 1904, and among its municipal undertakings is a
+technical college (1905). The corporation consists of a mayor, 6
+aldermen and 18 councillors. Area, 33201/2 acres.
+
+
+
+
+EASTHAMPTON, a township of Hampshire county, Mass., U.S.A., in the
+Connecticut Valley. Pop. (1900) 5603, of whom 1731 were foreign-born;
+(1905) 6808; (1910) 8524. It is served by the Boston & Maine, and the
+New York, New Haven & Hartford railways, and by interurban electric
+railways. The township is generally level, and is surrounded by high
+hills. In Easthampton are a free public library and Williston Seminary;
+the latter, one of the oldest and largest preparatory schools in New
+England, was founded in 1841 by the gifts of Samuel Williston
+(1795-1874) and Emily Graves Williston (1797-1885). Mr and Mrs Williston
+built up the industry of covering buttons with cloth, at first doing the
+work by hand, then (1827) experimenting with machinery, and in 1848
+building a factory for making and covering buttons. As the soil was
+fertile and well watered, the township had been agricultural up to this
+time. It is now chiefly devoted to manufacturing. Among its products are
+cotton goods, especially mercerised goods, for the manufacture of which
+it has one of the largest plants in the country; rubber, thread, elastic
+fabrics, suspenders and buttons. Parts of Northampton and Southampton
+were incorporated as the "district" of Easthampton in 1785; it became a
+township in 1809, and in 1841 and 1850 annexed parts of Southampton.
+
+
+
+
+EAST HAMPTON, a township of Suffolk county, New York, in the extreme
+S.E. part of Long Island, occupying the peninsula of Montauk, and
+bounded on the S. and E. by the Atlantic Ocean, and on the N. by Block
+Island Sound, Gardiner's Bay and Peconic Bay. Pop. (1900) 3746; (1905)
+4303; (1910) 4722. The township, 25 m. long and 8 m. at its greatest
+width from north to south, has an irregular north coast-line and a very
+regular south coast-line. The surface is rougher to the west where there
+are several large lakes, notably Great Pond, 2 m. long. The scenery is
+picturesque and the township is much frequented by artists. Montauk
+Lighthouse, on Turtle Hill, was first built in 1795. At Montauk, after
+the Spanish-American War, was Camp Wikoff, a large U.S. military camp.
+The township is served by the southern division of the Long Island
+railway, the terminus of which is Montauk. Other villages of the
+township, all summer resorts, are: Promised Land, Amagansett, East
+Hampton and Sag Harbor; the last named, only partly in the township, was
+incorporated in 1803 and had a population of 1969 in 1900, and 3084 in
+1910. Silverware and watch cases are manufactured here. From Sag Harbor,
+which is a port of entry, a daily steamer runs to New York city. The
+village received many gifts in 1906-1908 from Mrs Russell Sage. Most of
+the present township was bought from the Indians (Montauks, Corchaugs
+and Shinnecocks) in 1648 for about L30, through the governors of
+Connecticut and New Haven, by nine Massachusetts freemen, mostly
+inhabitants of Lynn, Massachusetts. With twenty other families they
+settled here in 1649, calling the place Maidstone, from the old home of
+some of the settlers in Kent; but as early as 1650 the name East Hampton
+was used in reference to the earlier settlement of South Hampton. Until
+1664, when all Long Island passed to the duke of York, the government
+was by town meeting, autonomous and independent except for occasional
+appeals to Connecticut. In 1683 Gardiner's Island, settled by Lion
+Gardiner in 1639 and so one of the first English settlements in what is
+now New York state, was made a part of Long Island and of East Hampton
+township. The English settlements in East Hampton were repeatedly
+threatened by pirates and privateers, and there are many stories of
+treasure buried by Captain Kidd on Gardiner's Island and on Montauk
+Point. The Clinton Academy, opened in East Hampton village in 1785, was
+long a famous school. Of the church built here in 1653 (first
+Congregational and after 1747 Presbyterian in government), Lyman Beecher
+was pastor in 1799-1810; and in East Hampton were born his elder
+children. Whale fishing was begun in East Hampton in 1675, when four
+Indians were engaged by whites in off-shore whaling; but Sag Harbor,
+which was first settled in 1730 and was held by the British after the
+battle of Long Island as a strategic naval and shipping point, became
+the centre of the whaling business. The first successful whaling voyage
+was made from Sag Harbor in 1785, and although the Embargo ruined the
+fishing for a time, it revived during 1830-1850. Cod and menhaden
+fishing, the latter for the manufacture of fish-oil and guano, were
+important for a time, but in the second half of the 19th century Sag
+Harbor lost its commercial importance.
+
+
+
+
+EAST INDIA COMPANY, an incorporated company for exploiting the trade
+with India and the Far East. In the 17th and 18th centuries East India
+companies were established by England, Holland, France, Denmark,
+Scotland, Spain, Austria and Sweden. By far the most important of these
+was the English East India Company, which became the dominant power in
+India, and only handed over its functions to the British Government in
+1858 (see also DUTCH EAST INDIA COMPANY, OSTEND COMPANY).
+
+
+  English East India Co.
+
+The English East India Company was founded at the end of the 16th
+century in order to compete with the Dutch merchants, who had obtained a
+practical monopoly of the trade with the Spice Islands, and had raised
+the price of pepper from 3s. to 8s. per lb. Queen Elizabeth incorporated
+it by royal charter, dated December 31, 1600, under the title of "The
+Governor and Company of Merchants of London, trading into the East
+Indies." This charter conferred the sole right of trading with the East
+Indies, i.e. with all countries lying beyond the Cape of Good Hope or
+the Straits of Magellan, upon the company for a term of 15 years.
+Unauthorized interlopers were liable to forfeiture of ships and cargo.
+There were 125 shareholders in the original East India Company, with a
+capital of L72,000: the first governor was Sir Thomas Smythe. The early
+voyages of the company, from 1601 to 1612, are distinguished as the
+"separate voyages," because the subscribers individually bore the cost
+of each voyage and reaped the whole profits, which seldom fell below
+100%. After 1612 the voyages were conducted on the joint stock system
+for the benefit of the company as a whole. These early voyages, whose
+own narratives may be read in Purchas, pushed as far as Japan, and
+established friendly relations at the court of the Great Mogul. In
+1610-1611 Captain Hippon planted the first English factories on the
+mainland of India, at Masulipatam and at Pettapoli in the Bay of Bengal.
+The profitable nature of the company's trade had induced James I. to
+grant subsidiary licences to private traders; but in 1609 he renewed the
+company's charter "for ever," though with a proviso that it might be
+revoked on three years' notice if the trade should not prove profitable
+to the realm.
+
+
+  English and Dutch disputes.
+
+Meanwhile friction was arising between the English and Dutch East India
+Companies. The Dutch traders considered that they had prior rights in
+the Far East, and their ascendancy in the Indian Archipelago was indeed
+firmly established on the basis of territorial dominion and authority.
+In 1613 they made advances to the English company with a suggestion for
+co-operation, but the offer was declined, and the next few years were
+fertile in disputes between the armed traders of both nations. In 1619
+was ratified a "treaty of defence" to prevent disputes between the
+English and Dutch companies. When it was proclaimed in the East,
+hostilities solemnly ceased for the space of an hour, while the Dutch
+and English fleets, dressed out in all their flags and with yards
+manned, saluted each other; but the treaty ended in the smoke of that
+stately salutation, and perpetual and fruitless contentions between the
+Dutch and English companies went on just as before. In 1623 these
+disputes culminated in the "massacre of Amboyna," where the Dutch
+governor tortured and executed the English residents on a charge of
+conspiring to seize the fort. Great and lasting indignation was aroused
+in England, but it was not until the time of Cromwell that some
+pecuniary reparation was exacted for the heirs of the victims. The
+immediate result was that the English company tacitly admitted the Dutch
+claims to a monopoly of the trade in the Far East, and confined their
+operations to the mainland of India and the adjoining countries.
+
+
+  The East Indiamen.
+
+The necessity of good ships for the East Indian trade had led the
+company in 1609 to construct their dockyard at Deptford, from which, as
+Monson observes, dates "the increase of great ships in England." Down to
+the middle of the 19th century, the famous "East Indiamen" held
+unquestioned pre-eminence among the merchant vessels of the world.
+Throughout the 17th century they had to be prepared at any moment to
+fight not merely Malay pirates, but the armed trading vessels of their
+Dutch, French and Portuguese rivals. Many such battles are recorded in
+the history of the East India Company, and usually with successful
+results.
+
+
+  The acquisition of territory.
+
+It was not until it had been in existence for more than a century that
+the English East India Company obtained a practical monopoly of the
+Indian trade. In 1635, a year after the Great Mogul had granted it the
+liberty of trading throughout Bengal, Charles I. issued a licence to
+Courten's rival association, known as "the Assada Merchants," on the
+ground that the company had neglected English interests. The piratical
+methods of their rivals disgraced the company with the Mogul officials,
+and a _modus vivendi_ was only reached in 1649. In 1657 Cromwell renewed
+the charter of 1609, providing that the Indian trade should be in the
+hands of a single joint stock company. The new company thus formed
+bought up the factories, forts and privileges of the old one. It was
+further consolidated by the fostering care of Charles II., who granted
+it five important charters. From a simple trading company, it grew under
+his reign into a great chartered company--to use the modern term--with
+the right to acquire territory, coin money, command fortresses and
+troops, form alliances, make war and peace, and exercise both civil and
+criminal jurisdiction. It is accordingly in 1689, when the three
+presidencies of Bengal, Madras and Bombay had lately been established,
+that the ruling career of the East India Company begins, with the
+passing by its directors of the following resolution for the guidance of
+the local governments in India:--"The increase of our revenue is the
+subject of our care, as much as our trade; 'tis that must maintain our
+force when twenty accidents may interrupt our trade; 'tis that must make
+us a nation in India; without that we are but a great number of
+interlopers, united by His Majesty's royal charter, fit only to trade
+where nobody of power thinks it their interest to prevent us; and upon
+this account it is that the wise Dutch, in all their general advices
+that we have seen, write ten paragraphs concerning their government,
+their civil and military policy, warfare, and the increase of their
+revenue, for one paragraph they write concerning trade." From this
+moment the history of the transactions of the East India Company becomes
+the history of British India (see INDIA: _History_). Here we shall only
+trace the later changes in the constitution and powers of the ruling
+body itself.
+
+
+  The interlopers.
+
+The great prosperity of the company under the Restoration, and the
+immense profits of the Indian trade, attracted a number of private
+traders, both outside merchants and dismissed or retired servants of the
+company, who came to be known as "interlopers." In 1683 the case of
+Thomas Sandys, an interloper, raised the whole question of the royal
+prerogative to create a monopoly of the Indian trade. The case was tried
+by Judge Jeffreys, who upheld the royal prerogative; but in spite of his
+decision the custom of interloping continued and laid the foundation of
+many great fortunes. By 1691 the interlopers had formed themselves into
+a new society, meeting at Dowgate, and rivalling the old company; the
+case was carried before the House of Commons, which declared in 1694
+that "all the subjects of England have equal right to trade to the East
+Indies unless prohibited by act of parliament." This decision led up to
+the act of 1698, which created a new East India Company in consideration
+of a loan of two millions to the state. The old company subscribed
+L315,000 and became the dominant factor in the new body; while at the
+same time it retained its charter for three years, its factories, forts
+and assured position in India. The rivalry between the two companies
+continued both in England and in India, until they were finally
+amalgamated by a tripartite indenture between the companies and Queen
+Anne (1702), which was ratified under the Godolphin Award (1708). Under
+this award the company was to lend the nation L3,200,000, and its
+exclusive privileges were to cease at three years' notice after this
+amount had been repaid. But by this time the need for permanence in the
+Indian establishment began to be felt, while parliament would not
+relinquish its privilege of "milking" the company from time to time. In
+1712 an act was passed continuing the privileges of the company even
+after their fund should be redeemed; in 1730 the charter was prolonged
+until 1766, and in 1742 the term was extended until 1783 in return for
+the loan of a million. This million was required for the war with
+France, which extended to India and involved the English and French
+companies there in long-drawn hostilities, in which the names of Dupleix
+and Clive became prominent.
+
+
+  The company and the crown.
+
+So long as the company's chief business was that of trade, it was left
+to manage its own affairs. The original charter of Elizabeth had placed
+its control in the hands of a governor and a committee of twenty-four,
+and this arrangement subsisted in essence down to the time of George
+III. The chairman and court of directors in London exercised unchecked
+control over their servants in India. But after Clive's brilliant
+victory at Plassey (1757) had made the company a ruling power in India,
+it was felt to be necessary that the British government should have some
+control over the territories thus acquired. Lord North's Regulating Act
+(1773) raised the governor of Bengal--Warren Hastings--to the rank of
+governor-general, and provided that his nomination, though made by a
+court of directors, should in future be subject to the approval of the
+crown; in conjunction with a council of four, he was entrusted with the
+power of peace and war; a supreme court of judicature was established,
+to which the judges were appointed by the crown; and legislative power
+was conferred on the governor-general and his council. Next followed
+Pitt's India Bill (1784), which created the board of control, as a
+department of the English government, to exercise political, military
+and financial superintendence over the British possessions in India.
+This bill first authorized the historic phrase "governor-general in
+council." From this date the direction of Indian policy passed
+definitely from the company to the governor-general in India and the
+ministry in London. In 1813 Lord Liverpool passed a bill which further
+gave the board of control authority over the company's commercial
+transactions, and abolished its monopoly of Indian trade, whilst leaving
+it the monopoly of the valuable trade with China, chiefly in tea.
+Finally, under Earl Grey's act of 1833, the company was deprived of this
+monopoly also. Its property was then secured on the Indian possessions,
+and its annual dividends of ten guineas per L100 stock were made a
+charge upon the Indian revenue. Henceforward the East India Company
+ceased to be a trading concern and exercised only administrative
+functions. Such a position could not, in the nature of things, be
+permanent, and the great cataclysm of the Indian Mutiny was followed by
+the entire transference of Indian administration from the company to the
+crown, on the 2nd of August 1858.
+
+  See _Purchas his Pilgrimes_ (ed. 1905), vols. 2, 3, 4, 5, for the
+  charter of Elizabeth and the early voyages; Sir W.W. Hunter, _History
+  of British India_ (1899); Beckles Willson, _Ledger and Sword_ (1903);
+  Sir George Birdwood, _Report on the Old Records of the India Office_
+  (1879); _The East India Company's First Letter Book_ (1895), _Letters
+  Received by the East India Company from its Servants in the East_, ed.
+  Foster, (1896 ff.). See also the interesting memorial volume _Relics
+  of the Honourable East India Company_ (ed. Griggs, 1909), letterpress
+  by Sir G. Birdwood and W. Foster.
+
+
+
+
+EAST INDIES, a name formerly applied vaguely, in its widest sense, to
+the whole area of India, Further India and the Malay Archipelago, in
+distinction from the West Indies, which, at the time of their discovery,
+were taken to be the extreme parts of the Indian region. The term "East
+Indies" is still sometimes applied to the Malay Archipelago (q.v.)
+alone, and the phrase "Dutch East Indies" is commonly used to denote the
+Dutch possessions which constitute the greater part of that archipelago.
+The Dutch themselves use the term _Nederlandsch-Indie_.
+
+
+
+
+EASTLAKE, SIR CHARLES LOCK (1793-1865), English painter, was born on the
+17th of November 1793 at Plymouth, where his father, a man of uncommon
+gifts but of indolent temperament, was solicitor to the admiralty and
+judge advocate of the admiralty court. Charles was educated (like Sir
+Joshua Reynolds) at the Plympton grammar-school, and in London at the
+Charterhouse. Towards 1809, partly through the influence of his
+fellow-Devonian Haydon, of whom he became a pupil, he determined to be a
+painter; he also studied in the Royal Academy school. In 1813 he
+exhibited in the British Institution his first picture, a work of
+considerable size, "Christ restoring life to the Daughter of Jairus." In
+1814 he was commissioned to copy some of the paintings collected by
+Napoleon in the Louvre; he returned to England in 1815, and practised
+portrait-painting at Plymouth. Here he saw Napoleon a captive on the
+"Bellerophon"; from a boat he made some sketches of the emperor, and he
+afterwards painted, from these sketches and from memory, a life-sized
+full-length portrait of him (with some of his officers) which was
+pronounced a good likeness; it belongs to the marquess of Lansdowne. In
+1817 Eastlake went to Italy; in 1819 to Greece; in 1820 back to Italy,
+where he remained altogether fourteen years, chiefly in Rome and in
+Ferrara.
+
+In 1827 he exhibited at the Royal Academy his picture of the Spartan
+Isidas, who (as narrated by Plutarch in the life of Agesilaus), rushing
+naked out of his bath, performed prodigies of valour against the Theban
+host. This was the first work that attracted much notice to the name of
+Eastlake, who in consequence obtained his election as A.R.A.; in 1830,
+when he returned to England, he was chosen R.A. In 1850 he succeeded
+Shee as president of the Royal Academy, and was knighted. Prior to this,
+in 1841, he had been appointed secretary to the royal commission for
+decorating the Houses of Parliament, and he retained this post until the
+commission was dissolved in 1862. In 1843 he was made keeper of the
+National Gallery, a post which he resigned in 1847 in consequence of an
+unfortunate purchase that roused much animadversion, a portrait
+erroneously ascribed to Holbein; in 1855, director of the same
+institution, with more extended powers. During his directorship he
+purchased for the gallery 155 pictures, mostly of the Italian schools.
+He became also a D.C.L. of Oxford, F.R.S., a chevalier of the Legion of
+Honour, and member of various foreign academies.
+
+In 1849 he married Miss Elizabeth Rigby, who had already then become
+known as a writer (_Letters from the Baltic_, 1841; _Livonian Tales_,
+1846; _The Jewess_, 1848) and as a contributor to the _Quarterly
+Review_. Lady Eastlake (1809-1893) had for some years been interested in
+art subjects, and after her marriage she naturally devoted more
+attention to them, translating Waagen's _Treasures of Art in Great
+Britain_ (1854-1857), and completing Mrs Jameson's _History of our Lord
+in Works of Art_. In 1865 Sir Charles Eastlake fell ill at Milan; and he
+died at Pisa on the 24th of December in the same year. Lady Eastlake,
+who survived him for many years, continued to play an active part as a
+writer on art (_Five Great Painters_, 1883, &c.), and had a large circle
+of friends among the most interesting men and women of the day. In 1880
+she published a volume of _Letters from France_ (describing events in
+Paris during 1789), written by her father, Edward Rigby (1747-1821), a
+distinguished Norwich doctor who was known also for his practical
+interest in agriculture, and who is said to have made known the flying
+shuttle to Norwich manufacturers.
+
+As a painter, Sir Charles Eastlake was gentle, harmonious, diligent and
+correct; lacking fire of invention or of execution; eclectic, without
+being exactly imitative; influenced rather by a love of ideal grace and
+beauty than by any marked bent of individual power or vigorous
+originality. Among his principal works (which were not numerous, 51
+being the total exhibited in the Academy) are: 1828, "Pilgrims arriving
+in sight of Rome" (repeated in 1835 and 1836, and perhaps on the whole
+his _chef-d'oeuvre_); 1829, "Byron's Dream" (in the Tate Gallery); 1834,
+the "Escape of Francesco di Carrara" (a duplicate in the Tate Gallery);
+1841, "Christ Lamenting over Jerusalem" (ditto); 1843, "Hagar and
+Ishmael"; 1845, "Comus"; 1849, "Helena"; 1851, "Ippolita Torelli"; 1853,
+"Violante"; 1855, "Beatrice." These female heads, of a refined
+semi-ideal quality, with something of Venetian glow of tint, are the
+most satisfactory specimens of Eastlake's work to an artist's eye. He
+was an accomplished and judicious scholar in matters of art, and
+published, in 1840, a translation of Goethe's _Theory of Colours_; in
+1847 (his chief literary work) _Materials for a History of
+Oil-Painting_, especially valuable as regards the Flemish school; in
+1848, _Contributions to the Literature of the Fine Arts_ (a second
+series was edited by Lady Eastlake in 1870, and accompanied by a Memoir
+from her pen); in 1851 and 1855, translated editions of Kugler's
+_History of the Italian School of Painting_, and _Handbook of Painting_
+(new edition, by Lady Eastlake, 1874).
+
+  See W. Cosmo Monkhouse, _Pictures by Sir Charles Eastlake, with
+  biographical and critical Sketch_ (1875).     (W. M. R.)
+
+
+
+
+EAST LIVERPOOL, a city of Columbiana county, Ohio, U.S.A., on the Ohio
+river, about 106 m. S.E. of Cleveland. Pop. (1890) 10,956; (1900)
+16,485, of whom 2112 were foreign-born; (1910 census) 20,357. It is
+served by the Pennsylvania railway, by river steamboats, and by
+interurban electric lines. Next to Trenton, New Jersey, East Liverpool
+is the most important place in the United States for the manufacture of
+earthenware and pottery, 4859 out of its 5228 wage-earners, or 92.9%,
+being employed in this industry in 1905, when $5,373,852 (83.5% of the
+value of all its factory products) was the value of the earthenware and
+pottery. No other city in the United States is so exclusively devoted to
+the manufacture of pottery; in 1908 there were 32 potteries in the city
+and its immediate vicinity. The manufacture of white ware, begun in
+1872, is the most important branch of the industry--almost half of the
+"cream-coloured," white granite ware and semivitreous porcelain produced
+in the United States in 1905 (in value, $4,344,468 out of $9,195,703)
+being manufactured in East Liverpool. Though there are large clay
+deposits in the vicinity, very little of it can be used for crockery,
+and most of the clay used in the city's potteries is obtained from other
+states; some of it is imported from Europe. After 1872 a large number of
+skilled English pottery-workers settled in the city. The city's product
+of pottery, terra-cotta and fireclay increased from $2,137,063 to
+$4,105,200 from 1890 to 1900, and in the latter year almost equalled
+that of Trenton, N.J., the two cities together producing more than half
+(50.9%) of the total pottery product of the United States; in 1905 East
+Liverpool and Trenton together produced 42.1% of the total value of the
+country's pottery product. The municipality owns and operates its
+water-works. East Liverpool was settled in 1798, and was incorporated in
+1834.
+
+
+
+
+EAST LONDON, a town of the Cape province, South Africa, at the mouth of
+the Buffalo river, in 33 deg. 1' S. 27 deg. 55' E., 543 m. E.N.E. of Cape Town
+by sea and 666 m. S. of Johannesburg by rail. Pop. (1904) 25,220, of
+whom 14,674 were whites. The town is picturesquely situated on both
+sides of the river, which is spanned by a combined road and railway
+bridge. The railway terminus and business quarter are on the east side
+on the top of the cliffs, which rise 150 ft. above the river. In Oxford
+Street, the chief thoroughfare, is the town hall, a handsome building
+erected in 1898. Higher up a number of churches and a school are
+grouped round Vincent Square, a large open space. In consequence of the
+excellent sea bathing, and the beauty of the river banks above the town,
+East London is the chief seaside holiday resort of the Cape province.
+The town is the entrepot of a rich agricultural district, including the
+Transkei, Basutoland and the south of Orange Free State, and the port of
+the Cape nearest Johannesburg. It ranks third among the ports of the
+province. The roadstead is exposed and insecure, but the inner harbour,
+constructed at a cost of over L2,000,000, is protected from all winds. A
+shifting sand bar lies at the mouth of the river, but the building of
+training walls and dredging have increased the minimum depth of water to
+22 ft. From the east bank of the Buffalo a pier and from the west bank a
+breakwater project into the Indian Ocean, the entrance being 450 ft.
+wide, reduced between the training walls to 250 ft. There is extensive
+wharf accommodation on both sides of the river, and steamers of over
+8000 tons can moor alongside. There is a patent slip capable of taking
+vessels of 1000 tons dead weight. An aerial steel ropeway from the river
+bank to the town greatly facilitates the delivery of cargo. The imports
+are chiefly textiles, hardware and provisions, the exports mainly wool
+and mohair. The rateable value of the town in 1908 was L4,108,000, and
+the municipal rate 1-5/8 d.
+
+East London owes its foundation to the necessities of the Kaffir war of
+1846-1847. The British, requiring a port nearer the scene of war than
+those then existing, selected a site at the mouth of the Buffalo river,
+and in 1847 the first cargo of military stores was landed. A fort, named
+Glamorgan, was built, and the place permanently occupied. Around this
+military post grew up the town, known at first as Port Rex. Numbers of
+its inhabitants are descendants of German immigrants who settled in the
+district in 1857. The prosperity of the town dates from the era of
+railway and port development in the last decade of the 19th century. In
+1875 the value of the exports was L131,803 and that of the imports
+L552,033. In 1904 the value of the exports was L1,165,938 and that of
+the imports L4,688,415. In 1907 the exports, notwithstanding a period of
+severe trade depression, were valued at L1,475,355, but the imports had
+fallen to L3,354,633.
+
+
+
+
+EASTON, a city and the county-seat of Northampton county, Pennsylvania,
+U.S.A., at the confluence of the Lehigh river and Bushkill Creek with
+the Delaware, about 60 m. N. of Philadelphia. Pop. (1890) 14,481; (1900)
+25,238, of whom 2135 were foreign-born; (1910 census) 28,523. Easton is
+served by the Central of New Jersey, the Lehigh Valley, the Lehigh &
+Hudson River and the Delaware, Lackawanna & Western railways, and is
+connected by canals with the anthracite coal region to the north-west
+and with Bristol, Pa. A bridge across the Delaware river connects it
+with Phillipsburg, New Jersey, which is served by the Pennsylvania
+railway. The city is built on rolling ground, commanding pleasant views
+of hill and river scenery. Many fine residences overlook city and
+country from the hillsides, and a Carnegie library is prominent among
+the public buildings. Lafayette College, a Presbyterian institution
+opened in 1832, is finely situated on a bluff north of the Bushkill and
+Delaware. The college provides the following courses of instruction:
+graduate, classical, Latin scientific, general scientific, civil
+engineering, electrical engineering, mining engineering and chemical; in
+1908 it had 38 instructors and 442 students, 256 of whom were enrolled
+in the scientific and engineering courses. Overlooking the Bushkill is
+the Easton Cemetery, in which is the grave of George Taylor (1716-1781),
+a signer of the Declaration of Independence, with a monument of Italian
+marble to his memory. Among the city's manufactures are silk, hosiery
+and knit goods, flour, malt liquors, brick, tile, drills, lumber and
+planing mill products and organs; in 1905 the value of all the factory
+products was $5,654,594, of which $2,290,598, or 40.5%, was the value of
+the silk manufactures. Easton is the commercial centre of an important
+mining region, which produces, in particular, iron ore, soapstone,
+cement, slate and building stone. The municipality owns and operates an
+electric-lighting plant. Easton was a garden spot of the Indians, and
+here, because they would not negotiate elsewhere, several important
+treaties were made between 1756 and 1762 during the French and Indian
+War. The place was laid out in 1752, and was made the county-seat of the
+newly erected county. It was incorporated as a borough in 1789, received
+a new borough charter in 1823, and in 1887 was chartered as a city.
+South Easton was annexed in 1898.
+
+
+
+
+EAST ORANGE, a city of Essex county, New Jersey, U.S.A., in the
+north-eastern part of the state, adjoining the city of Newark, and about
+12 m. W. of New York city. Pop. (1890) 13,282; (1900) 21,506, of whom
+3950 were foreign-born and 1420 were negroes; (1910 census) 34,371. It
+is served by the Morris & Essex division of the Delaware, Lackawanna &
+Western railway and by the Orange branch of the Erie (the former having
+four stations--Ampere, Grove Street, East Orange and Brick Church), and
+is connected with Newark, Orange and West Orange by electric line. The
+city covers an area of about 4 sq. m., and has broad, well-paved
+streets, bordered with fine shade trees (under the jurisdiction of a
+"Shade Tree Commission"). It is primarily a residential suburb of New
+York and Newark, and has many beautiful homes; with Orange, West Orange
+and South Orange it forms virtually one community, popularly known as
+"the Oranges." The public school system is excellent, and the city has a
+Carnegie library (1903), with more than 22,000 volumes in 1907. Among
+the principal buildings are several attractive churches, the city hall,
+and the club-house of the Woman's Club of Orange. The principal
+manufactures of East Orange are electrical machinery, apparatus, and
+supplies (the factory of the Crocker-Wheeler Co. being here--in a part
+of the city known as "Ampere") and pharmaceutical materials. The total
+value of the city's factory products in 1905 was $2,326,552. East Orange
+has a fine water-works system, which it owns and operates; the water
+supply is obtained from artesian wells at White Oaks Ridge, in the
+township of Milburn (about 10 m. from the city hall); thence the water
+is pumped to a steel reinforced reservoir (capacity 5,000,000 gallons)
+on the mountain back of South Orange. In 1863 the township of East
+Orange was separated from the township of Orange, which, in turn, had
+been separated from the township of Newark in 1806. An act of the New
+Jersey legislature in 1895 created the office of township president,
+with power of appointment and veto. Four years later East Orange was
+chartered as a city.
+
+  See H. Whittemore, _The Founders and Builders of the Oranges_ (Newark,
+  1896).
+
+
+
+
+EASTPORT, a city and port of entry of Washington county, Maine, U.S.A.,
+co-extensive with Moose Island in Passamaquoddy Bay, about 190 m. E.N.E.
+of Portland. Pop. (1890) 4908; (1900) 5311 (1554 foreign-born); (1910)
+4961. It is served by the Washington County railway, and by steamboat
+lines to Boston, Portland and Calais. It is the most eastern city of the
+United States, and is separated from the mainland by a narrow channel,
+which is spanned by a bridge. The harbour is well protected from the
+winds, and the tide, which rises and falls here about 25 ft., prevents
+it from being obstructed with ice. The city is built on ground sloping
+gently to the water's edge, and commands delightful views of the bay, in
+which there are several islands. Its principal industry is the canning
+of sardines; there are also clam canneries. Shoes, mustard, decorated
+tin, and shooks are manufactured, and fish and lobsters are shipped from
+here in the season. The city is the port of entry for the customs
+district of Passamaquoddy; in 1908 its imports were valued at $994,961,
+and its exports at $1,155,791. Eastport was first settled about 1782 by
+fishermen; it became a port of entry in 1790, was incorporated as a town
+in 1798, and was chartered as a city in 1893. It was a notorious place
+for smuggling under the Embargo Acts of 1807 and 1808. On the 11th of
+July 1814, during the war of 1812, it was taken by the British. As the
+British government claimed the islands of Passamaquoddy Bay under the
+treaty of 1783, the British forces retained possession of Eastport after
+the close of the war and held it under martial law until July 1818, when
+it was surrendered in accordance with the decision rendered in November
+1817 by commissioners appointed under Article IV. of the treaty of Ghent
+(1814), this decision awarding Moose Island, Dudley Island and Frederick
+Island to the United States and the other islands, including the Island
+of Grand Manan in the Bay of Fundy, to Great Britain.
+
+
+
+
+EAST PROVIDENCE, a township of Providence county, Rhode Island, U.S.A.,
+on the E. side of Providence river, opposite Providence. Pop. (1890)
+8422; (1900) 12,138, of whom 2067 were foreign-born; (1910 census)
+15,808. Area, 121/2 sq. m. It is served by the New York, New Haven &
+Hartford railway. It has a rolling surface and contains several
+villages, one of which, known as Rumford, has important manufactories of
+chemicals and electrical supplies. South of this village, along the
+river bank, are several attractive summer resorts, Hunt's Mills, Silver
+Spring, Riverside, Vanity Fair, Kettle Point and Bullock's Point being
+prominent among them. In 1905 the factory products of the township were
+valued at $5,035,288. The oyster trade is important. It was within the
+present limits of this township that Roger Williams established himself
+in the spring of 1636, until he learned that the place was within the
+jurisdiction of the Plymouth Colony. About 1644 it was settled by a
+company from Weymouth as a part of a town of Rehoboth. In 1812 Rehoboth
+was divided, and the west part was made the township of Seekonk.
+Finally, in 1861, it was decided that the west part of Seekonk belonged
+to Rhode Island, and in the following year that part was incorporated as
+the township of East Providence.
+
+
+
+
+EAST PRUSSIA (_Ost-Preussen_), the easternmost province of the kingdom
+of Prussia, bounded on the N. by the Baltic, on the E. and S.W. by
+Russia and Russian Poland, and on the W. by the Prussian province of
+West Prussia. It has an area of 14,284 sq. m., and had, in 1905, a
+population of 2,025,741. It shares in the general characteristics of the
+great north German plain, but, though low, its surface is by no means
+absolutely flat, as the southern half is traversed by a low ridge or
+plateau, which attains a height of 1025 ft. at a point near the western
+boundary of the province. This plateau, here named the Prussian
+Seenplatte, is thickly sprinkled with small lakes, among which is the
+Spirding See, 46 sq. m. in extent and the largest inland lake in the
+Prussian monarchy. The coast is lined with low dunes or sandhills, in
+front of which lie the large littoral lakes or lagoons named the
+Frisches Haff and the Kurisches Haff. The first of these receives the
+waters of the Nogat and the Pregel, and the other those of the Memel or
+Niemen. East Prussia is the coldest part of Germany, its mean annual
+temperature being about 44 deg. F., while the mean January temperature of
+Tilsit is only 25 deg.. The rainfall is 24 in. per annum. About half the
+province is under tillage; 18% is occupied by forests, and about 23% by
+meadows and pastures. The most fertile soil is found in the valleys of
+the Pregel and the Memel, but the southern slopes of the Baltic plateau
+and the district to the north of the Memel consist in great part of
+sterile moor, sand and bog. The chief crops are rye, oats and potatoes,
+while flax is cultivated in the district of Ermeland, between the
+Passarge and the upper Alle. East Prussia is the headquarters of the
+horse-breeding of the country, and contains the principal government
+stud of Trakehnen; numerous cattle are also fattened on the rich
+pastures of the river-valleys. The extensive woods in the south part of
+the province harbour a few wolves and lynxes, and the elk is still
+preserved in the forest of Ibenhorst, near the Kurisches Haff. The
+fisheries in the lakes and haffs are of some importance; but the only
+mineral product of note is amber, which is found in the peninsula of
+Samland in greater abundance than in any other part of the world.
+Manufactures are almost confined to the principal towns, though
+linen-weaving is practised as a domestic industry. Commerce is
+facilitated by canals connecting the Memel and Pregel and also the
+principal lakes, but is somewhat hampered by the heavy dues exacted at
+the Russian frontier. A brisk foreign trade is carried on through the
+seaports of Koenigsberg, the capital of the province, and Memel, the
+exports consisting mainly of timber and grain.
+
+The population of the province was in 1900 1,996,626, and included
+1,698,465 Protestants, 269,196 Roman Catholics and 13,877 Jews. The
+Roman Catholics are mainly confined to the district of Ermeland, in
+which the ordinary proportions of the confessions are completely
+reversed. The bulk of the inhabitants are of German blood, but there are
+above 400,000 Protestant Poles (Masurians or Masovians) in the south
+part of the province, and 175,000 Lithuanians in the north. As in other
+provinces where the Polish element is strong, East Prussia is somewhat
+below the general average of the kingdom in education. There is a
+university at Koenigsberg.
+
+  See Lohmeyer, _Geschichte von Ost- und West-Preussen_ (Gotha, 1884);
+  Bruenneck, _Zur Geschichte des Kirchen-Patronats in Ost- und
+  West-Preussen_ (Berlin, 1902), and _Ost-Preussen, Land und Volk_
+  (Stuttgart, 1901-1902).
+
+
+
+
+EASTWICK, EDWARD BACKHOUSE (1814-1883), British Orientalist, was born in
+1814, a member of an Anglo-Indian family. Educated at Charterhouse and
+at Oxford, he joined the Bombay infantry in 1836, but, owing to his
+talent for languages, was soon given a political post. In 1843 he
+translated the Persian _Kessahi Sanjan_, or _History of the Arrival of
+the Parsees in India_; and he wrote a _Life of Zoroaster_, a _Sindhi_
+vocabulary, and various papers in the transactions of the Bombay Asiatic
+Society. Compelled by ill-health to return to Europe, he went to
+Frankfort, where he learned German and translated Schiller's _Revolt of
+the Netherlands_ and Bopp's _Comparative Grammar_. In 1845 he was
+appointed professor of Hindustani at Haileybury College. Two years later
+he published a Hindustani grammar, and, in subsequent years, a new
+edition of the _Gulistan_, with a translation in prose and verse, also
+an edition with vocabulary of the Hindi translation by Lallu Lal of
+Chatur Chuj Misr's _Prem Sagar_, and translations of the _Bagh-o-Bahar_,
+and of the _Anvar-i Suhaili_ of Bidpai. In 1851 he was elected a Fellow
+of the Royal Society. In 1857-1858 he edited _The Autobiography of
+Lutfullah_. He also edited for the Bible Society the Book of Genesis in
+the Dakhani language. From 1860 to 1863 he was in Persia as secretary to
+the British Legation, publishing on his return _The Journal of a
+Diplomate_. In 1866 he became private secretary to the secretary of
+state for India, Lord Cranborne (afterwards marquess of Salisbury), and
+in 1867 went, as in 1864, on a government mission to Venezuela. On his
+return he wrote, at the request of Charles Dickens, for _All the Year
+Round_, "Sketches of Life in a South American Republic." From 1868 to
+1874 he was M.P. for Penryn and Falmouth. In 1875 he received the degree
+of M.A. with the franchise from the university of Oxford, "as a slight
+recognition of distinguished services." At various times he wrote
+several of Murray's Indian hand-books. His last work was the
+_Kaisarnamah-i-Hind_ ("the lay of the empress"), in two volumes
+(1878-1882). He died at Ventnor, Isle of Wight, on the 16th of July
+1883.
+
+
+
+
+EATON, DORMAN BRIDGMAN (1823-1899), American lawyer, was born at
+Hardwick, Vermont, on the 27th of June 1823. He graduated at the
+university of Vermont in 1848 and at the Harvard Law School in 1850, and
+in the latter year was admitted to the bar in New York city. There he
+became associated in practice with William Kent, the son of the great
+chancellor, an edition of whose _Commentaries_ he assisted in editing.
+Eaton early became interested in municipal and civil service reform. He
+was conspicuous in the fight against Tweed and his followers, by one of
+whom he was assaulted; he required a long period of rest, and went to
+Europe, where he studied the workings of the civil service in various
+countries. From 1873 to 1875 he was a member of the first United States
+Civil Service Commission. In 1877, at the request of President Hayes, he
+made a careful study of the British civil service, and three years later
+published _Civil Service in Great Britain_. He drafted the Pendleton
+Civil Service Act of 1883, and later became a member of the new
+commission established by it. He resigned in 1885, but was almost
+immediately reappointed by President Cleveland, and served until 1886,
+editing the 3rd and 4th _Reports_ of the commission. He was an organizer
+(1878) of the first society for the furtherance of civil service reform
+in New York, of the National Civil Service Reform Association, and of
+the National Conference of the Unitarian Church (1865). He died in New
+York city on the 23rd of December 1899, leaving $100,000 each to Harvard
+and Columbia universities for the establishments of professorships in
+government. He was a legal writer and editor, and a frequent contributor
+to the leading reviews. In addition to the works mentioned he published
+_Should Judges be Elected?_ (1873), _The Independent Movement in New
+York_ (1880), _Term and Tenure of Office_ (1882), _The Spoils System and
+Civil Service Reform_ (1882), _Problems of Police Legislation_ (1895)
+and _The Government of Municipalities_ (1899).
+
+  See the privately printed memorial volume, _Dorman B. Eaton_,
+  1823-1899 (New York, 1900).
+
+
+
+
+EATON, MARGARET O'NEILL (1796-1879), better known as PEGGY O'NEILL, was
+the daughter of the keeper of a popular Washington tavern, and was noted
+for her beauty, wit and vivacity. About 1823, she married a purser in
+the United States navy, John B. Timberlake, who committed suicide while
+on service in the Mediterranean in 1828. In the following year she
+married John Henry Eaton (1790-1856), a Tennessee politician, at the
+time a member of the United States Senate. Senator Eaton was a close
+personal friend of President Jackson, who in 1829 appointed him
+secretary of war. This sudden elevation of Mrs Eaton into the cabinet
+social circle was resented by the wives of several of Jackson's
+secretaries, and charges were made against her of improper conduct with
+Eaton previous to her marriage to him. The refusal of the wives of the
+cabinet members to recognize the wife of his friend angered President
+Jackson, and he tried in vain to coerce them. Eventually, and partly for
+this reason, he almost completely reorganized his cabinet. The effect of
+the incident on the political fortunes of the vice-president, John C.
+Calhoun, whose wife was one of the recalcitrants, was perhaps most
+important. Partly on this account, Jackson's favour was transferred from
+Calhoun to Martin Van Buren, the secretary of state, who had taken
+Jackson's side in the quarrel and had shown marked attention to Mrs
+Eaton, and whose subsequent elevation to the vice-presidency and
+presidency through Jackson's favour is no doubt partly attributable to
+this incident. In 1836 Mrs Eaton accompanied her husband to Spain, where
+he was United States minister in 1836-1840. After the death of her
+husband she married a young Italian dancing-master, Antonio Buchignani,
+but soon obtained a divorce from him. She died in Washington on the 8th
+of November 1879.
+
+  See James Parton's _Life of Andrew Jackson_ (New York, 1860).
+
+
+
+
+EATON, THEOPHILUS (c. 1590-1658), English colonial governor in America,
+was born at Stony Stratford, Buckinghamshire, about 1590. He was
+educated in Coventry, became a successful merchant, travelled widely
+throughout Europe, and for several years was the financial agent of
+Charles I. in Denmark. He subsequently settled in London, where he
+joined the Puritan congregation of the Rev. John Davenport, whom he had
+known since boyhood. The pressure upon the Puritans increasing, Eaton,
+who had been one of the original patentees of the Massachusetts Bay
+colony in 1629, determined to use his influence and fortune to establish
+an independent colony of which his pastor should be the head. In 1637 he
+emigrated with Davenport to Massachusetts, and in the following year
+(March 1638) he and Davenport founded New Haven. In October 1639 a form
+of government was adopted, based on the Mosaic Law, and Eaton was
+elected governor, a post which he continued to hold by annual
+re-election, first over New Haven alone, and after 1643 over the New
+Haven Colony or Jurisdiction, until his death at New Haven on the 7th of
+January 1658. His administration was embarrassed by constantly recurring
+disputes with the neighbouring Dutch settlements, especially after
+Stamford (Conn.) and Southold (Long Island) had entered the New Haven
+Jurisdiction, but his prudence and diplomacy prevented an actual
+outbreak of hostilities. He was prominent in the affairs of the New
+England Confederation, of which he was one of the founders (1643). In
+1655 he and Davenport drew up the code of laws, popularly known as the
+"Connecticut Blue Laws," which were published in London in 1656 under
+the title _New Haven's Settling in New England and some Lawes for
+Government published for the Use of that Colony_.
+
+  A sketch of his life appears in Cotton Mather's _Magnalia_ (London,
+  1702); see also J.B. Moore's "Memoir of Theophilus Eaton" in the
+  _Collections_ of the New York Historical Society, second series, vol.
+  ii. (New York, 1849).
+
+
+
+
+EATON, WILLIAM (1764-1811), American soldier, was born in Woodstock,
+Connecticut, on the 23rd of February 1764. As a boy he served for a
+short time in the Continental army. He was a school teacher for several
+years, graduated at Dartmouth College in 1790, was clerk of the lower
+house of the Vermont legislature in 1791-1792, and in 1792 re-entered
+the army as a captain, later serving against the Indians in Ohio and
+Georgia. In 1797 he was appointed consul to Tunis, where he arrived in
+February 1799. In March 1799, with the consuls to Tripoli and Algiers,
+he negotiated alterations in the treaty of 1797 with Tunis. He rendered
+great service to Danish merchantmen by buying on credit several Danish
+prizes in Tunis and turning them over to their original owners for the
+redemption of his notes. In 1803 he quarrelled with the Bey, was ordered
+from the country, and returned to the United States to urge American
+intervention for the restoration of Ahmet Karamanli to the throne of
+Tripoli, arguing that this would impress the Barbary States with the
+power of the United States. In 1804 he returned to the Mediterranean as
+United States naval agent to the Barbary States with Barron's fleet. On
+the 23rd of February 1805 he agreed with Ahmet that the United States
+should undertake to re-establish him in Tripoli, that the expenses of
+the expedition should be repaid to the United States by Ahmet, and that
+Eaton should be general and commander-in-chief of the land forces in
+Ahmet's campaign; as the secretary of the navy had given the entire
+matter into the hands of Commodore Barron, and as Barron and Tobias Lear
+(1762-1816), the United States consul-general at Algiers and a
+diplomatic agent to conduct negotiations, had been instructed to
+consider the advisability of making arrangements with the existing
+government in Tripoli, Eaton far exceeded his authority. On the 8th of
+March he started for Derna across the Libyan desert from the Arab's
+Tower, 40 m. W. of Alexandria, with a force of about 500 men, including
+a few Americans, about 40 Greeks and some Arab cavalry. In the march of
+nearly 600 m. the camel-drivers and the Arab chiefs repeatedly mutinied,
+and Ahmet Pasha once put himself at the head of the Arabs and ordered
+them to attack Eaton. Ahmet more than once wished to give up the
+expedition. There were practically no provisions for the latter part of
+the march. On the 27th of April with the assistance of three bombarding
+cruisers Eaton captured Derna--an exploit commemorated by Whittier's
+poem _Derne_. On the 13th of May and on the 10th of June he successfully
+withstood the attacks of Tripolitan forces sent to dislodge him. On the
+12th of June he abandoned the town upon orders from Commodore Rodgers,
+for Lear had made peace (4th June) with Yussuf, the _de facto_ Pasha of
+Tripoli. Eaton returned to the United States, and received a grant of
+10,000 acres in Maine from the Massachusetts legislature. According to a
+deposition which he made in January 1807 he was approached by Aaron Burr
+(q.v.), who attempted to enlist him in his "conspiracy," and wished him
+to win over the marine corps and to sound Preble and Decatur. As he
+received from the government, soon after making this deposition, about
+$10,000 to liquidate claims for his expense in Tripoli, which he had
+long pressed in vain, his good faith has been doubted. At Burr's trial
+at Richmond in 1807 Eaton was one of the witnesses, but his testimony
+was unimportant. In May 1807 he was elected a member of the
+Massachusetts House of Representatives, and served for one term. He died
+on the 1st of June 1811 in Brimfield, Massachusetts.
+
+  See the anonymously published _Life of the Late Gen. William Eaton_
+  (Brookfield, Massachusetts, 1813) by Charles Prentiss; C.C. Felton,
+  "Life of William Eaton" in Sparks's _Library of American Biography_,
+  vol. ix. (Boston, 1838); and Gardner W. Allen's _Our Navy and the
+  Barbary Corsairs_ (Boston, 1905).
+
+
+
+
+EATON, WYATT (1849-1896), American portrait and figure painter, was born
+at Philipsburg, Canada, on the 6th of May 1849. He was a pupil of the
+schools of the National Academy of Design, New York, and in 1872 went to
+Paris, where he studied in the Ecole des Beaux-Arts under J.L. Gerome.
+He made the acquaintance of J.F. Millet at Barbizon, and was also
+influenced by his friend Jules Bastien-Lepage. After his return to the
+United States in 1876 he became a teacher in Cooper Institute and opened
+a studio in New York city. He was one of the organizers (and the first
+secretary) of the Society of American Artists. Among his portraits are
+those of William Cullen Bryant and Timothy Cole, the wood engraver ("The
+Man with the Violin"). Eaton died at Newport, Rhode Island, on the 7th
+of June 1896.
+
+
+
+
+EAU CLAIRE, a city and the county-seat of Eau Claire county, Wisconsin,
+U.S.A., on the Chippewa river, at the mouth of the Eau Claire, about 87
+m. E. of St Paul. Pop. (1890) 17,415; (1900) 17,517, of whom 4996 were
+foreign-born; (1910 census) 18,310. It is served by the Chicago &
+North-Western, the Chicago, Milwaukee & St Paul, and the Wisconsin
+Central railways, and is connected by an electric line with Chippewa
+Falls (12 m. distant). The city has a Carnegie library with 17,200
+volumes in 1908, a Federal building, county court house, normal school
+and insane asylum. It has abundant water-power, and is an important
+lumber manufacturing centre; among its other manufactures are flour,
+wooden-ware, agricultural machinery, saw-mill machinery, logging
+locomotives, wood pulp, paper, linen, mattresses, shoes and trunks. The
+total value of factory products in 1905 was $3,601,558. The city is the
+principal wholesale and jobbing market for the prosperous Chippewa
+Valley. Eau Claire was first settled about 1847, and was chartered as a
+city in 1872; its growth dates from the development of the north-western
+lumber trade in the decade 1870-1880. In 1881 a serious strike
+necessitated the calling out of state militia for its suppression and
+the protection of property.
+
+
+
+
+EAU DE COLOGNE (Ger. _Koelnisches Wasser_, "Cologne water"), a perfume,
+so named from the city of Cologne, where its manufacture was first
+established by an Italian, Johann (or Giovanni) Maria Farina
+(1685-1766), who settled at Cologne in 1709. The perfume gained a high
+reputation by 1766, and Farina associated himself with his nephew, to
+whose grandson the secret was ultimately imparted; the original perfume
+is still manufactured by members of this family under the name of the
+founder. The manufacture is, however, carried on at Cologne, and also in
+Italy, by other firms bearing the name Farina, and the scent has become
+part of the regular output of perfumers. The discovery has also been
+ascribed to a Paul de Feminis, who is supposed to have brought his
+recipe from Milan to Cologne, of which he became a citizen in 1690, and
+sold the perfume under the name _Eau admirable_, leaving the secret at
+his death to his nephew Johann Maria Farina. Certain of the Farinas
+claim to use his process. It was originally prepared by making an
+alcoholic infusion of certain flowers, pot-herbs, drugs and spices,
+distilling and then adding definite quantities of several vegetable
+essences. The purity and thorough blending of the ingredients are of the
+greatest importance. The original perfume is simulated and even excelled
+by artificial preparations. The oils of lemon, bergamot and orange are
+employed, together with the oils of neroli and rosemary in the better
+class. The common practice consists in dissolving the oils, in certain
+definite proportions based on experience, in pure alcohol and
+distilling, the distillate being diluted by rose-water.
+
+
+
+
+EAUX-BONNES, a watering-place of south-western France, in the department
+of Basses-Pyrenees, 31/2 m. S.E. of the small town of Laruns, the latter
+being 24 m. S. of Pau by rail. Pop. (1906) 610. Eaux-Bonnes is situated
+at a height of 2460 ft. at the entrance of a fine gorge, overlooking the
+confluence of two torrents, the Valentin and the Sourde. The village is
+well known for its sulphurous and saline mineral waters (first mentioned
+in the middle of the 14th century), which are beneficial in affections
+of the throat and lungs. They vary between 50 deg. and 90 deg. F. in
+temperature, and are used for drinking and bathing. There are two
+thermal establishments, a casino and fine promenades.
+
+The watering-place of LES EAUX-CHAUDES is 5 m. by road south-west of
+Eaux-Bonnes, in a wild gorge on the Gave d'Ossau. The springs are
+sulphurous, varying in temperature from 52 deg. to 97 deg. F., and are used in
+cases of rheumatism, certain maladies of women, &c. The thermal
+establishment is a handsome marble building.
+
+There is fine mountain scenery in the neighbourhood of both places, the
+Pic de Ger near Eaux-Bonnes, commanding an extensive view. The valley of
+Ossau, one of the most beautiful in the Pyrenees, before the Revolution
+formed a community which, though dependent on Bearn, had its own legal
+organization, manners and costumes, the last of which are still to be
+seen on holidays.
+
+
+
+
+EAVES (not a plural form as is sometimes supposed, but singular; O. Eng.
+_efes_, in Mid. High Ger. _obse_, Gothic _ubizwa_, a porch; connected
+with "over"), in architecture, the projecting edge of a sloping roof,
+which overhangs the face of the wall so as to throw off the water.
+
+
+
+
+EAVESDRIP, or EAVESDROP, that width of ground around a house or building
+which receives the rain water dropping from the eaves. By an ancient
+Saxon law, a landowner was forbidden to erect any building at less than
+2 ft. from the boundary of his land, and was thus prevented from
+injuring his neighbour's house or property by the dripping of water from
+his eaves. The law of Eavesdrip has had its equivalent in the Roman
+_stillicidium_, which prohibited building up to the very edge of an
+estate.
+
+From the Saxon custom arose the term "eavesdropper," i.e. any one who
+stands within "the eavesdrop" of a house, hence one who pries into
+others' business or listens to secrets. At common law an eavesdropper
+was regarded as a common nuisance, and was presentable at the court
+leet, and indictable at the sheriff's tourn and punishable by fine and
+finding sureties for good behaviour. Though the offence of eavesdropping
+still exists at common law, there is no modern instance of a prosecution
+or indictment.
+
+
+
+
+EBBW VALE, an urban district in the western parliamentary division of
+Monmouthshire, England, 21 m. N.W. of Newport on the Great Western,
+London & North-Western and Rhymney railways. Pop. (1891) 17,312; (1901)
+20,994. It lies near the head of the valley of the river Ebbw, at an
+elevation of nearly 1000 ft., in a wild and mountainous mining district,
+which contains large collieries and important iron and steel works.
+
+
+
+
+EBEL, HERMANN WILHELM (1820-1875), German philologist, was born at
+Berlin on the 10th of May 1820. He displayed in his early years a
+remarkable capacity for the study of languages, and at the same time a
+passionate fondness for music and poetry. At the age of sixteen he
+became a student at the university of Berlin, applying himself
+especially to philology, and attending the lectures of Boeckh. Music
+continued to be the favourite occupation of his leisure hours, and he
+pursued the study of it under the direction of Marx. In the spring of
+1838 he passed to the university of Halle, and there began to apply
+himself to comparative philology under Pott. Returning in the following
+year to his native city, he continued this study as a disciple of Bopp.
+He took his degree in 1842, and, after spending his year of probation at
+the French Gymnasium of Berlin, he resumed with great earnestness his
+language studies. About 1847 he began to study Old Persian. In 1852 he
+accepted a professorship at the Beheim-Schwarzbach Institution at
+Filehne, which post he held for six years. It was during this period
+that his studies in the Old Slavic and Celtic languages began. In 1858
+he removed to Schneidemuehl, and there he discharged the duties of first
+professor for ten years. He was afterwards called to the chair of
+comparative philology at the university of Berlin. He died at Misdroy on
+the 19th of August 1875. The most important work of Dr Ebel in the field
+of Celtic philology is his revised edition of the _Grammatica Celtica_
+of Professor Zeuss, completed in 1871. This had been preceded by his
+treatises--_De verbi Britannici futuro ac conjunctivo_ (1866), and _De
+Zeussii curis positis in Grammatica Celtica_ (1869). He made many
+learned contributions to Kuehn's _Zeitschrift fuer vergleichende
+Sprachforschung_, and to A. Schleicher's _Beitraege zur vergleichenden
+Sprachforschung_; and a selection of these contributions was translated
+into English by Sullivan, and published under the title of _Celtic
+Studies_ (1863). Ebel contributed the Old Irish section to Schleicher's
+_Indogermanische Chrestomathie_ (1869). Among his other works must be
+named _Die Lehnwoerter der deutschen Sprache_ (1856).
+
+
+
+
+EBEL, JOHANN GOTTFRIED (1764-1830), the author of the first real
+guide-book to Switzerland, was born at Zuellichau (Prussia). He became a
+medical man, visited Switzerland for the first time in 1790, and became
+so enamoured of it that he spent three years exploring the country and
+collecting all kinds of information relating to it. The result was the
+publication (Zuerich, 1793) of his _Anleitung auf die nuetzlichste und
+genussvollste Art in der Schweitz zu reisen_ (2 vols.), in which he gave
+a complete account of the country, the General Information sections
+being followed by an alphabetically arranged list of places, with
+descriptions. It at once superseded all other works of the kind, and was
+the best Swiss guide-book till the appearance of "Murray" (1838). It was
+particularly strong on the geological and historical sides. The second
+(1804-1805) and third (1809-1810) editions filled four volumes, but the
+following (the 8th appeared in 1843) were in a single volume. The work
+was translated into French in 1795 (many later editions) and into
+English (by 1818). Ebel also published a work (2 vols., Leipzig,
+1798-1802) entitled _Schilderungen der Gebirgsvoelker der Schweiz_, which
+deals mainly with the pastoral cantons of Glarus and Appenzell. In 1801
+he was naturalized a Swiss citizen, and settled down in Zuerich. In 1808
+he issued his chief geological work, _Ueber den Bau der Erde im
+Alpengebirge_ (Zuerich, 2 vols.). He took an active share in promoting
+all that could make his adopted country better known, e.g. Heinrich
+Keller's map (1813), the building of a hotel on the Rigi (1816), and the
+preparation of a panorama from that point (1823). From 1810 onwards he
+lived at Zuerich, with the family of his friend, Conrad Escher von der
+Linth (1767-1823), the celebrated engineer.     (W. A. B. C.)
+
+
+
+
+EBER, PAUL (1511-1569), German theologian, was born at Kitzingen in
+Franconia, and was educated at Nuremberg and Wittenberg, where he became
+the close friend of Philip Melanchthon. In 1541 he was appointed
+professor of Latin grammar at Wittenberg, and in 1557 professor of the
+Old Testament. His range of learning was wide, and he published a
+handbook of Jewish history, a historical calendar intended to supersede
+the Roman Saints' Calendar, and a revision of the Latin Old Testament.
+In the theological conflict of the time he played a large part, doing
+what he could to mediate between the extremists. From 1559 to the close
+of his life he was superintendent-general of the electorate of Saxony.
+He attained some fame as a hymn-writer, his best-known composition being
+"Wenn wir in hoechsten Noethen sein." He died at Wittenberg on the 10th of
+December 1569.
+
+
+
+
+EBERBACH, a town of Germany, in the grand-duchy of Baden, romantically
+situated on the Neckar, at the foot of the Katzenbuckel, 19 m. E. of
+Heidelberg by the railway to Wuerzburg. Pop. (1900) 5857. It contains an
+Evangelical and a Roman Catholic church, a commercial and a technical
+school, and, in addition to manufacturing cigars, leather and cutlery,
+carries on by water an active trade in timber and wine. Eberbach was
+founded in 1227 by the German king Henry VII., who acquired the castle
+(the ruins of which overhang the town) from the bishop of Worms. It
+became an imperial town and passed later to the Palatinate.
+
+  See Wirth, _Geschichte der Stadt Eberbach_ (Stuttgart, 1864).
+
+
+
+
+EBERBACH, a famous Cistercian monastery of Germany, in the Prussian
+province of Hesse-Nassau, situated near Hattenheim in the Rheingau, 10
+m. N.W. from Wiesbaden. Founded in 1116 by Archbishop Adalbert of Mainz,
+as a house of Augustinian canons regular, it was bestowed by him in 1131
+upon the Benedictines, but was shortly afterwards repurchased and
+conferred upon the Cistercian order. The Romanesque church (consecrated
+in 1186) contains numerous interesting monuments and tombs, notable
+among them being those of the archbishop of Mainz, Gerlach (d. 1371)
+and Adolph II. of Nassau (d. 1475). It was despoiled during the Thirty
+Years' War, was secularized in 1803, and now serves as a house of
+correction. Its cellars contain some of the finest vintages of the Rhine
+wines of the locality.
+
+  See Baer, _Diplomatische Geschichte der Abtei Eberbach_ (Wiesb.,
+  1851-1858 and 1886, 3 vols.), and Schaefer, _Die Abtei Eberbach im
+  Mittelalter_ (Berlin, 1901).
+
+
+
+
+EBERHARD, surnamed IM BART (_Barbatus_), count and afterwards duke of
+Wuerttemberg (1445-1496), was the second son of Louis I., count of
+Wuerttemberg-Urach (d. 1450), and succeeded his elder brother Louis II.
+in 1457. His uncle Ulrich V., count of Wuerttemberg-Stuttgart (d. 1480),
+acted as his guardian, but in 1459, assisted by Frederick I., elector
+palatine, he threw off this restraint, and undertook the government of
+the district of Urach as Count Eberhard V. He neglected his duties as a
+ruler and lived a reckless life until 1468, when he made a pilgrimage to
+Jerusalem. He visited Italy, became acquainted with some famous
+scholars, and in 1474 married Barbara di Gonzaga, daughter of Lodovico
+III., marquis of Mantua, a lady distinguished for her intellectual
+qualities. In 1482 he brought about the treaty of Muensingen with his
+cousin Eberhard VI., count of Wuerttemberg-Stuttgart. By this treaty the
+districts of Urach and Stuttgart into which Wuerttemberg had been divided
+in 1437 were again united, and for the future the county was declared
+indivisible, and the right of primogeniture established. The treaty led
+to some disturbances, but in 1492 the sanction of the nobles was secured
+for its provisions. In return for this Eberhard agreed to some
+limitations on the power of the count, and so in a sense founded the
+constitution of Wuerttemberg. At the diet of Worms in 1495 the emperor
+Maximilian I. guaranteed the treaty, confirmed the possessions and
+prerogatives of the house of Wuerttemberg, and raised Eberhard to the
+rank of duke. Eberhard, although a lover of peace, was one of the
+founders of the Swabian League in 1488, and assisted to release
+Maximilian, then king of the Romans, from his imprisonment at Bruges in
+the same year. He gave charters to the towns of Stuttgart and Tuebingen,
+and introduced order into the convents of his land, some of which he
+secularized. He took a keen interest in the new learning, founded the
+university of Tuebingen in 1476, befriended John Reuchlin, whom he made
+his private secretary, welcomed scholars to his court, and is said to
+have learned Latin in later life. In 1482 he again visited Italy and
+received the Golden Rose from Pope Sixtus IV. He won the esteem of the
+emperors Frederick III. and Maximilian I. on account of his wisdom and
+fidelity, and his people held him in high regard. His later years were
+mainly spent at Stuttgart, but he died at Tuebingen on the 25th of
+February 1496, and in 1537 his ashes were placed in the choir of the
+Stiftskirche there. Eberhard left no children, and the succession passed
+to his cousin Eberhard, who became Duke Eberhard II.
+
+  See Roesslin, _Leben Eberhards im Barte_ (Tuebingen, 1793); Bossert,
+  _Eberhard im Bart_ (Stuttgart, 1884).
+
+
+
+
+EBERHARD, CHRISTIAN AUGUST GOTTLOB (1769-1845), German miscellaneous
+writer, was born at Belzig, near Wittenberg, on the 12th of January
+1769. He studied theology at Leipzig; but, a story he contributed to a
+periodical having proved successful, he devoted himself to literature.
+With the exception of _Hannchen und die Kuechlein_ (1822), a narrative
+poem in ten parts, and an epic on the Creation, _Der erste Mensch und
+die Erde_ (1828), Eberhard's work was ephemeral in character and is now
+forgotten. He died at Dresden on the 13th of May 1845.
+
+  His collected works (_Gesammelte Schriften_) appeared in 20 volumes in
+  1830-1831.
+
+
+
+
+EBERHARD, JOHANN AUGUSTUS (1739-1809), German theologian and
+philosopher, was born at Halberstadt in Lower Saxony, where his father
+was singing-master at the church of St Martin's, and teacher of the
+school of the same name. He studied theology at the university of Halle,
+and became tutor to the eldest son of the baron von der Horst, to whose
+family he attached himself for a number of years. In 1763 he was
+appointed con-rector of the school of St Martin's, and second preacher
+in the hospital church of the Holy Ghost; but he soon afterwards
+resigned these offices and followed his patron to Berlin. There he met
+Nicolai and Moses Mendelssohn, with whom he formed a close friendship.
+In 1768 he became preacher or chaplain to the workhouse at Berlin and
+the neighbouring fishing village of Stralow. Here he wrote his _Neue
+Apologie des Socrates_ (1772), a work occasioned by an attack on the
+fifteenth chapter of Marmontel's _Belisarius_ made by Peter Hofstede, a
+clergyman of Rotterdam, who maintained the patristic view that the
+virtues of the noblest pagans were only _splendida peccata_. Eberhard
+stated the arguments for the broader view with dignity, acuteness and
+learning, but the liberality of the reasoning gave great offence to the
+strictly orthodox divines, and is believed to have obstructed his
+preferment in the church.
+
+In 1774 he was appointed to the living of Charlottenburg. A second
+volume of his _Apologie_ appeared in 1778. In this he not only
+endeavoured to obviate some objections which were taken to the former
+part, but continued his inquiries into the doctrines of the Christian
+religion, religious toleration and the proper rules for interpreting the
+Scriptures. In 1778 he accepted the professorship of philosophy at
+Halle. As an academical teacher, however, he was unsuccessful. His
+powers as an original thinker were not equal to his learning and his
+literary gifts, as was shown in his opposition to the philosophy of
+Kant. In 1786 he was admitted a member of the Berlin Academy of
+Sciences; in 1805 the king of Prussia conferred upon him the honorary
+title of a privy-councillor. In 1808 he obtained the degree of doctor in
+divinity, which was given him as a reward for his theological writings.
+He died on the 6th of January 1809. He was master of the learned
+languages, spoke and wrote French with facility and correctness, and
+understood English, Italian and Dutch. He possessed a just and
+discriminating taste for the fine arts, and was a great lover of music.
+
+  Works:--_Neue Apologie des Socrates_, &c. (2 vols., 1772-1778);
+  _Allgemeine Theorie des Denkens und Empfindens_, &c. (Berlin, 1776),
+  an essay which gained the prize assigned by the Royal Society of
+  Berlin for that year; _Von dem Begriff der Philosophie und ihren
+  Theilen_ (Berlin, 1778)--a short essay, in which he announced the plan
+  of his lectures on being appointed to the professorship at Halle;
+  _Lobschrift auf Herrn Johann Thunmann Prof. der Weltweisheit und
+  Beredsamkeit auf der Universitaet zu Halle_ (Halle, 1779); _Amyntor,
+  eine Geschichte in Briefen_ (Berlin, 1782)--written with the view of
+  counteracting the influence of those sceptical and Epicurean
+  principles in religion and morals then so prevalent in France, and
+  rapidly spreading amongst the higher ranks in Germany; _Ueber die
+  Zeichen der Aufklaerung einer Nation_, &c. (Halle, 1783); _Theorie der
+  schoenen Kuenste und Wissenschaften_, &c. (Halle, 1783, 3rd ed. 1790);
+  _Vermischte Schriften_ (Halle, 1784); _Neue vermischte Schriften_ (ib.
+  1786); _Allgemeine Geschichte der Philosophie_, &c. (Halle, 1788), 2nd
+  ed. with a continuation and chronological tables (1796); _Versuch
+  einer allgemeinen-deutschen Synonymik_ (Halle and Leipzig, 1795-1802,
+  6 vols., 4th ed. 1852-1853), long reckoned the best work on the
+  synonyms of the German language (an abridgment of it was published by
+  the author in one large volume, Halle, 1802); _Handbuch der Aesthetik_
+  (Halle, 1803-1805, 2nd ed. 1807-1820). He also edited the
+  _Philosophisches Magazin_ (1788-1792) and the _Philosophisches Archiv_
+  (1792-1795).
+
+  See F. Nicolai, _Gedaechtnisschrift auf J.A. Eberhard_ (Berlin and
+  Stettin, 1810); also K.H. Joerdens, _Lexicon deutscher Dichter und
+  Prosaisten_.
+
+
+
+
+EBERLIN, JOHANN ERNST (1702-1762), German musician and composer, was
+born in Bavaria, and became afterwards organist in the cathedral at
+Salzburg, where he died. Most of his compositions were for the church
+(oratorios, &c.), but he also wrote some important fugues, sonatas and
+preludes; and his pieces were at one time highly valued by Mozart.
+
+
+
+
+EBERS, GEORG MORITZ (1837-1898), German Egyptologist and novelist, was
+born in Berlin on the 1st of March 1837. At Goettingen he studied
+jurisprudence, and at Berlin oriental languages and archaeology. Having
+made a special study of Egyptology, he became in 1865 _docent_ in
+Egyptian language and antiquities at Jena, and in 1870 he was appointed
+professor in these subjects at Leipzig. He had made two scientific
+journeys to Egypt, and his first work of importance, _Aegypten und die
+Buecher Moses_, appeared in 1867-1868. In 1874 he edited the celebrated
+medical papyrus ("Papyrus Ebers") which he had discovered in Thebes
+(translation by H. Joachim, 1890). Ebers early conceived the idea of
+popularizing Egyptian lore by means of historical romances. _Eine
+aegyptische Koenigstochter_ was published in 1864, and obtained great
+success. His subsequent works of the same kind--_Uarda_ (1877), _Homo
+sum_ (1878), _Die Schwestern_ (1880), _Der Kaiser_ (1881), of which the
+scene is laid in Egypt at the time of Hadrian, _Serapis_ (1885), _Die
+Nilbraut_ (1887), and _Kleopatra_ (1894), were also well received, and
+did much to make the public familiar with the discoveries of
+Egyptologists. Ebers also turned his attention to other fields of
+historical fiction--especially the 16th century (_Die Frau
+Buergermeisterin_, 1882; _Die Gred_, 1887)--without, however, attaining
+the success of his Egyptian novels. Apart from their antiquarian and
+historical interest, Ebers's books have not a very high literary value.
+His other writings include a descriptive work on Egypt (_Aegypten in Wort
+und Bild_, 2nd ed., 1880), a guide to Egypt (1886) and a life (1885) of
+his old teacher, the Egyptologist Karl Richard Lepsius. The state of his
+health led him in 1889 to retire from his chair at Leipzig on a pension.
+He died at Tutzing in Bavaria, on the 7th of August 1898.
+
+  Ebers's _Gesammelte Werke_ appeared in 25 vols. at Stuttgart
+  (1893-1895). Many of his books have been translated into English. For
+  his life see his _Die Geschichte meines Lebens_ (Stuttgart, 1893);
+  also R. Gosche, _G. Ebers, der Forscher und Dichter_ (2nd ed.,
+  Leipzig, 1887).
+
+
+
+
+EBERSWALDE, a town of Germany, in the kingdom of Prussia, 28 m. N.E. of
+Berlin by rail; on the Finow canal. Pop. (1905) 23,876. The town has a
+Roman Catholic and two Evangelical churches, a school of forestry, a
+gymnasium, a higher-grade girls' school and two schools of domestic
+economy. It possesses a mineral spring, which attracts numerous summer
+visitors, and has various industries, which include iron-founding and
+the making of horse-shoe nails, roofing material and bricks. A
+considerable trade is carried on in grain, wood and coals. In the
+immediate neighbourhood are one of the chief brass-foundries in Germany
+and an extensive government paper-mill, in which the paper for the notes
+of the imperial bank is manufactured.
+
+Eberswalde received its municipal charter in 1257. It was taken and
+sacked during the Thirty Years' War. In 1747 Frederick the Great brought
+a colony of Thuringian cutlers to the town, but this branch of industry
+has entirely died out. About 4 m. to the north lies the old Cistercian
+monastery of Chorin, the fine Gothic church of which contains the tombs
+of several margraves of Brandenburg.
+
+
+
+
+EBERT, FRIEDRICH ADOLF (1791-1834), German bibliographer, was born at
+Taucha, near Leipzig, on the 9th of July 1791, the son of a Lutheran
+pastor. At the age of fifteen he was appointed to a subordinate post in
+the municipal library of Leipzig. He studied theology for a short time
+at Leipzig, and afterwards philology at Wittenberg, where he graduated
+doctor in philosophy in 1812. While still a student he had already
+published, in 1811, a work on public libraries, and in 1812 another work
+entitled _Hierarchiae in religionem ac literas commoda_. In 1813 he was
+attached to the Leipzig University library, and in 1814 was appointed
+secretary to the Royal library of Dresden. The same year he published
+_F. Taubmanns Leben und Verdienste_, and in 1819 _Torquato Tasso_, a
+translation from Pierre Louis Ginguene with annotations. The rich
+resources open to him in the Dresden library enabled him to undertake
+the work on which his reputation chiefly rests, the _Allgemeines
+bibliographisches Lexikon_, the first volume of which appeared in 1821
+and the second in 1830. This was the first work of the kind produced in
+Germany, and the most scientific published anywhere. From 1823 to 1825
+Ebert was librarian to the duke of Brunswick at Wolfenbuettel, but
+returning to Dresden was made, in 1827, chief librarian of the Dresden
+Royal library. Among his other works are--_Die Bildung des
+Bibliothekars_ (1820), _Geschichte und Beschreibung der koeniglichen
+oeffentlichen Bibliothek in Dresden_ (1822), _Zur Handschriftenkunde_
+(1825-1827), and _Culturperioden des obersaechsischen Mittelalters_
+(1825). Ebert was a contributor to various journals and took part in the
+editing of Ersch and Gruber's great encyclopaedia. He died at Dresden on
+the 13th of November 1834, in consequence of a fall from the ladder in
+his library.
+
+  See the article in _Ersch und Grubers Encyclopaedie_, and that in the
+  _Allg. deutsche Biog._ by his successor in the post of chief librarian
+  in Dresden, Schnorr von Carolsfeld.
+
+
+
+
+
+EBINGEN, a town of Germany, in the kingdom of Wuerttemberg, on the
+Schmiecha, a left-hand tributary of the Danube, 22 m. S. of Tuebingen and
+37 m. W. of Ulm by rail. It manufactures velvet and cotton-velvet
+("Manchester") goods, stockings, stays, hats, needles, tools, &c. There
+are also tanneries. Pop. 9000.
+
+
+
+
+EBIONITES (Heb. [Hebrew: ebyonim], "poor men"), a name given to the
+ultra-Jewish party in the early Christian church. It is first met with
+in Irenaeus (_Adv. Haer._ i. 26. 2), who sheds no light on the origin of
+the Ebionites, but says that while they admit the world to have been
+made by the true God (in contrast to the Demiurge of the Gnostics), they
+held Cerinthian views on the person of Christ, used only the Gospel of
+Matthew (probably the Gospel according to the Hebrews--so Eusebius), and
+rejected Paul as an apostate from the Mosaic Law, to the customs and
+ordinances of which, including circumcision, they steadily adhered. A
+similar account is given by Hippolytus (_Haer._ vii. 35), who invents a
+founder named Ebion. Origen (_Contra Celsum_, v. 61; _In Matt._ tom.
+xvi. 12) divides the Ebionites into two classes according to their
+acceptance or rejection of the virgin birth of Jesus, but says that all
+alike reject the Pauline epistles. This is confirmed by Eusebius, who
+adds that even those who admitted the virgin birth did not accept the
+pre-existence of Jesus as Logos and Sophia. They kept both the Jewish
+Sabbath and the Christian Lord's day, and held extreme millenarian ideas
+in which Jerusalem figured as the centre of the coming Messianic
+kingdom. Epiphanius with his customary confusion makes two separate
+sects, Ebionites and Nazarenes. Both names, however, refer to the same
+people[1] (the Jewish Christians of Syria), the latter going back to the
+designation of apostolic times (Acts xxiv. 5), and the former being the
+term usually applied to them in the ecclesiastical literature of the 2nd
+and 3rd centuries.
+
+The origin of the Nazarenes or Ebionites as a distinct sect is very
+obscure, but may be dated with much likelihood from the edict of Hadrian
+which in 135 finally scattered the old church of Jerusalem. While
+Christians of the type of Aristo of Pella and Hegesippus, on the
+snapping of the old ties, were gradually assimilated to the great church
+outside, the more conservative section became more and more isolated and
+exclusive. "It may have been then that they called themselves the Poor
+Men, probably as claiming to be the true representatives of those who
+had been blessed in the Sermon on the Mount, but possibly adding to the
+name other associations." Out of touch with the main stream of the
+church they developed a new kind of pharisaism. Doctrinally they stood
+not so much for a theology as for a refusal of theology, and, rejecting
+the practical liberalism of Paul, became the natural heirs of those
+early Judaizers who had caused the apostle so much annoyance and
+trouble.
+
+Though there is insufficient justification for dividing the Ebionites
+into two separate and distinct communities, labelled respectively
+Ebionites and Nazarenes, we have good evidence, not only that there were
+grades of Christological thought among them, but that a considerable
+section, at the end of the 2nd century and the beginning of the 3rd,
+exchanged their simple Judaistic creed for a strange blend of Essenism
+and Christianity. These are known as the Helxaites or Elchasaites, for
+they accepted as a revelation the "book of Elchasai," and one Alcibiades
+of Apamea undertook a mission to Rome about 220 to propagate its
+teaching. It was claimed that Christ, as an angel 96 miles high,
+accompanied by the Holy Spirit, as a female angel of the same stature,
+had given the revelation to Elchasai in the 3rd year of Trajan (A.D.
+100), but the book was probably quite new in Alcibiades' time. It taught
+that Christ was an angel born of human parents, and had appeared both
+before (e.g. in Adam and Moses) and after this birth in Judea. His
+coming did not annul the Law, for he was merely a prophet and teacher;
+Paul was wrong and circumcision still necessary. Baptism must be
+repeated as a means of purification from sin, and proof against disease;
+the sinner immerses himself "in the name of the mighty and most high
+God," invoking the "seven witnesses" (sky, water, the holy spirits, the
+angels of prayer, oil, salt and earth), and pledging himself to
+amendment. Abstinence from flesh was also enjoined, and a good deal of
+astrological fancy was interwoven with the doctrinal and practical
+teaching. It is highly probable, too, that from these Essene Ebionites
+there issued the fantastical and widely read "Clementine" literature
+(_Homilies_ and _Recognitions_) of the 3rd century. Ebionite views
+lingered especially in the country east of the Jordan until they were
+absorbed by Islam in the 7th century.
+
+  In addition to the literature cited see R.C. Ottley, _The Doctrine of
+  the Incarnation_, part iii. Sec. ii.; W. Moeller, _Hist. of the Christian
+  Church_, i. 99; art. in Herzog-Hauck, _Realencyklopaedie_, s.v.
+  "Ebioniten"; also CLEMENTINE LITERATURE.
+
+
+FOOTNOTE:
+
+  [1] So A. Harnack, _Hist. of Dogma_, i. 301, and F.J.A. Hort,
+    _Judaistic Christianity_, p. 199. Th. Zahn and J.B. Lightfoot ("St.
+    Paul and the Three," in _Commentary on Galatians_) maintain the
+    distinction.
+
+
+
+
+EBNER-ESCHENBACH, MARIE, FREIFRAU VON (1830- ), Austrian novelist, was
+born at Zdislavic in Moravia, on the 13th of September 1830, the daughter
+of a Count Dubsky. She lost her mother in early infancy, but received a
+careful intellectual training from two stepmothers. In 1848 she married
+the Austrian captain, and subsequent field-marshal, Moritz von
+Ebner-Eschenbach, and resided first at Vienna, then at Klosterbruck, where
+her husband had a military charge, and after 1860 again at Vienna. The
+marriage was childless, and the talented wife sought consolation in
+literary work. In her endeavours she received assistance and encouragement
+from Franz Grillparzer and Freiherr von Muench-Bellinghausen. Her first
+essay was with the drama _Maria Stuart in Schottland_, which Philipp
+Eduard Devrient produced at the Karlsruhe theatre in 1860. After some
+other unsuccessful attempts in the field of drama, she found her true
+sphere in narrative. Commencing with _Die Prinzessin von Banalien_ (1872),
+she graphically depicts in _Bozena_ (Stuttgart, 1876, 4th ed. 1899) and
+_Das Gemeindekind_ (Berlin, 1887, 4th ed. 1900) the surroundings of her
+Moravian home, and in _Lotti, die Uhrmacherin_ (Berlin, 1883, 4th ed.
+1900), _Zwei Comtessen_ (Berlin, 1885, 5th ed. 1898), _Unsuehnbar_ (1890,
+5th ed. 1900) and _Glaubenslos?_ (1893) the life of the Austrian
+aristocracy in town and country. She also published _Neue Erzaehlungen_
+(Berlin, 1881, 3rd ed. 1894), _Aphorismen_ (Berlin, 1880, 4th ed. 1895)
+and _Parabeln, Maerchen und Gedichte_ (2nd ed., Berlin, 1892). Frau von
+Ebner-Eschenbach's elegance of style, her incisive wit and masterly
+depiction of character give her a foremost place among the German
+women-writers of her time. On the occasion of her seventieth birthday the
+university of Vienna conferred upon her the degree of doctor of
+philosophy, _honoris causa_.
+
+  An edition of Marie von Ebner-Eschenbach's _Gesammelte Schriften_
+  began to appear in 1893 (Berlin). See A. Bettelheim, _Marie von
+  Ebner-Eschenbach: biographische Blaetter_ (Berlin, 1900), and M.
+  Necker, _Marie von Ebner-Eschenbach, nach ihren Werken geschildert_
+  (Berlin, 1900).
+
+
+
+
+EBOLI (anc. _Eburum_), a town of Campania, Italy, in the province of
+Salerno, from which it is 16 m. E. by rail, situated 470 ft. above
+sea-level, on the S. edge of the hills overlooking the valley of the
+Sele. Pop. (1901) 9642 (town), 12,423 (commune). The sacristy of St
+Francesco contains two 14th-century pictures, one by Roberto da Oderisio
+of Naples. The ancient Eburum was a Lucanian city, mentioned only by
+Pliny and in inscriptions, not far distant from the Campanian border. It
+lay above the Via Popillia, which followed the line taken by the modern
+railway. Some scanty remains of its ancient polygonal walls may still be
+seen.     (T. As.)
+
+
+
+
+EBONY (Gr. [Greek: ebenos]), the wood of various species of trees of the
+genus _Diospyros_ (natural order Ebenaceae), widely distributed in the
+tropical parts of the world. The best kinds are very heavy, are of a
+deep black, and consist of heart-wood only. On account of its colour,
+durability, hardness and susceptibility of polish, ebony is much used
+for cabinet work and inlaying, and for the manufacture of
+pianoforte-keys, knife-handles and turned articles. The best Indian and
+Ceylon ebony is furnished by _D. Ebenum_, a native of southern India and
+Ceylon, which grows in great abundance throughout the flat country west
+of Trincomalee. The tree is distinguished from others by the inferior
+width of its trunk, and its jet-black, charred-looking bark, beneath
+which the wood is perfectly white until the heart is reached. The wood
+is stated to excel that obtained from _D. reticulata_ of the Mauritius
+and all other varieties of ebony in the fineness and intensity of its
+dark colour. Although the centre of the tree alone is employed, reduced
+logs 1 to 3 ft. in diameter can readily be procured. Much of the East
+Indian ebony is yielded by the species _D. Melanoxylon_ (Coromandel
+ebony), a large tree attaining a height of 60 to 80 ft., and 8 to 10 ft.
+in circumference, with irregular rigid branches, and oblong or
+oblong-lanceolate leaves. The bark of the tree is astringent, and mixed
+with pepper is used in dysentery by the natives of India. The wood of
+_D. tomentosa_, a native of north Bengal, is black, hard and of great
+weight. _D. montana_, another Indian species, produces a yellowish-grey
+soft but durable wood. _D. quaesita_ is the tree from which is obtained
+the wood known in Ceylon by the name _Calamander_, derived by Pridham
+from the Sinhalee _kalumindrie_, black-flowing. Its closeness of grain,
+great hardness and fine hazel-brown colour, mottled and striped with
+black, render it a valuable material for veneering and furniture making.
+_D. Dendo_, a native of Angola, is a valuable timber tree, 25 to 35 ft.
+high, with a trunk 1 to 2 ft. in diameter. The heart-wood is very black
+and hard and is known as black ebony, also as billet-wood, and Gabun,
+Lagos, Calabar or Niger ebony. What is termed Jamaica or West Indian
+ebony, and also the green ebony of commerce, are produced by _Brya
+Ebenus_, a leguminous tree or shrub, having a trunk rarely more than 4
+in. in diameter, flexible spiny branches, and orange-yellow,
+sweet-scented flowers. The heart-wood is rich dark brown in colour,
+heavier than water, exceedingly hard and capable of receiving a high
+polish.
+
+From the book of Ezekiel (xxvii. 15) we learn that ebony was among the
+articles of merchandise brought to Tyre; and Herodotus states (iii. 97)
+that the Ethiopians every three years sent a tribute of 200 logs of it
+to Persia. Ebony was known to Virgil as a product of India (_Georg._ ii.
+116), and was displayed by Pompey the Great in his Mithradatic triumph
+at Rome. By the ancients it was esteemed of equal value for durability
+with the cypress and cedar (see Pliny, _Nat. Hist._ xii. 9, xvi. 79).
+According to Solinus (_Polyhistor_, cap. lv. p. 353, Paris, 1621), it
+was employed by the kings of India for sceptres and images, also, on
+account of its supposed antagonism to poison, for drinking-cups. The
+hardness and black colour of the wood appear to have given rise to the
+tradition related by Pausanias, and alluded to by Southey in _Thalaba_,
+i. 22, that the ebony tree produced neither leaves nor fruit, and was
+never seen exposed to the sun.
+
+
+
+
+EBRARD, JOHANNES HEINRICH AUGUST (1818-1888), German theologian, was
+born at Erlangen on the 18th of January 1818. He was educated in his
+native town and at Berlin, and after teaching in a private family became
+_Privatdocent_ at Erlangen (1841) and then professor of theology at
+Zuerich (1844). In 1847 he was appointed professor of theology at
+Erlangen, a chair which he resigned in 1861; in 1875 he became pastor of
+the French reformed church in the same city. As a critic Ebrard occupied
+a very moderate standpoint; as a writer his chief works were
+_Christliche Dogmatik_ (2 vols., 1851), _Vorlesungen ueber praktische
+Theologie_ (1864), _Apologetik_ (1874-1875, Eng. trans. 1886). He also
+edited and completed H. Olshausen's commentary, himself writing the
+volumes on the Epistle to the Hebrews, the Johannine Epistles, and
+Revelation. In the department of belles-lettres he wrote a good deal
+under such pseudonyms as Christian Deutsch, Gottfried Flammberg and
+Sigmund Sturm. He died at Erlangen on the 23rd of July 1888.
+
+
+
+
+EBRO (anc. _Iberus_ or _Hiberus_), the only one of the five great rivers
+of the Iberian Peninsula (Tagus, Douro, Ebro, Guadalquivir, Guadiana)
+which flows into the Mediterranean. The Ebro rises at Fuentibre, a
+hamlet among the Cantabrian Mountains, in the province of Santander; at
+Reinosa, 4 m. east, it is joined on the right by the Hijar, and thus
+gains considerably in volume. It flows generally east by south through a
+tortuous valley as far as Miranda de Ebro, passing through the
+celebrated Roman bridge known as La Horadada ("the perforated"), near
+Ona in Burgos. From Miranda it winds south-eastward through the wide
+basin enclosed on the right by the highlands of Old Castile and western
+Aragon, and on the left by the Pyrenees. The chief cities on its banks
+are Logrono, Calahorra, Tudela, Saragossa and Caspe. Near Mora in
+Catalonia it forces a way through the coastal mountains, and, passing
+Tortosa, falls into the Mediterranean about 80 m. south-west of
+Barcelona, after forming by its delta a conspicuous projection on the
+otherwise regular coast line. In its length, approximately 465 m., the
+Ebro is inferior to the Tagus, Guadiana and Douro; it drains an area of
+nearly 32,000 sq. m. Its principal tributaries are--from the right hand
+the Jalon with its affluent the Jiloca, the Huerva, Aguas, Martin,
+Guadalope and Matarrana; from the left the Ega, Aragon, Arba, Gallego,
+and the Segre with its intricate system of confluent rivers. The Ebro
+and its tributaries have been utilized for irrigation since the Moorish
+conquest; the main stream becomes navigable by small boats about Tudela;
+but its value as a means of communication is almost neutralized by the
+obstacles in its channel, and seafaring vessels cannot proceed farther
+up than Tortosa. The great Imperial Canal, begun under the emperor
+Charles V. (1500-1558), proceeds along the right bank of the river from
+a point about 3 m. below Tudela, to El Burgo de Ebro, 5 m. below
+Saragossa; the irrigation canal of Tauste skirts the opposite bank for a
+shorter distance; and the San Carlos or New Canal affords direct
+communication between Amposta at the head of the delta and the harbour
+of Los Alfaques. From Miranda to Mora the Bilbao-Tarragona railway
+follows the course of the Ebro along the right bank.
+
+
+
+
+EBROIN (d. 681), Frankish "mayor of the palace," was a Neustrian, and
+wished to impose the authority of Neustria over Burgundy and Austrasia.
+In 656, at the moment of his accession to power, Sigebert III., the king
+of Austrasia, had just died, and the Austrasian mayor of the palace,
+Grimoald, was attempting to usurp the authority. The great nobles,
+however, appealed to the king of Neustria, Clovis II., and unity was
+re-established. But in spite of a very firm policy Ebroin was unable to
+maintain this unity, and while Clotaire III., son of Clovis II., reigned
+in Neustria and Burgundy, he was obliged in 660 to give the Austrasians
+a special king, Childeric II., brother of Clotaire III., and a special
+mayor of the palace, Wulfoald. He endeavoured to maintain at any rate
+the union of Neustria and Burgundy, but the great Burgundian nobles
+wished to remain independent, and rose under St Leger (Leodegar), bishop
+of Autun, defeated Ebroin, and interned him in the monastery of Luxeuil
+(670). A proclamation was then issued to the effect that each kingdom
+should keep its own laws and customs, that there should be no further
+interchange of functionaries between the kingdoms, and that no one
+should again set up a tyranny like that of Ebroin. Soon, however, Leger
+was defeated by Wulfoald and the Austrasians, and was himself confined
+at Luxeuil in 673. In the same year, taking advantage of the general
+anarchy, Ebroin and Leger left the cloister and soon found themselves
+once more face to face. Each looked for support to a different
+Merovingian king, Ebroin even proclaiming a false Merovingian as
+sovereign. In this struggle Leger was vanquished; he was besieged in
+Autun, was forced to surrender and had his eyes put out, and, on the
+12th of October 678, he was put to death after undergoing prolonged
+tortures. The church honours him as a saint. After his death Ebroin
+became sole and absolute ruler of the Franks, imposing his authority
+over Burgundy and subduing the Austrasians, whom he defeated in 678 at
+Bois-du-Fay, near Laon. His triumph, however, was short-lived; he was
+assassinated in 681, the victim of a combined attack of his numerous
+enemies. He was a man of great energy, but all his actions seem to have
+been dictated by no higher motives than ambition and lust of power.
+
+  See _Liber historiae Francorum_, edited by B. Krusch, in _Mon. Germ.
+  hist. script. rer. Merov._ vol. ii.; _Vita sancti Leodegarii_, by
+  Ursinus, a monk of St Maixent (Migne, _Patr. Latina_, vol. xcvi.);
+  "Vita metrica" in _Poetae Latini aevi Carolini_, vol. iii. (_Mon.
+  Germ. hist._); J.B. Pitra, _Histoire de Saint Leger_ (Paris, 1846);
+  and J. Friedrich, "Zur Gesch. des Hausmeiers Ebroin," in the
+  _Proceedings of the Academy of Munich_ (1887, pp. 42-61).
+       (C. Pf.)
+
+
+
+
+EBURACUM, or EBORACUM (probably a later variant), the Roman name of York
+(q.v.) in England. Established about A.D. 75-80 as fortress of the
+Ninth legion and garrisoned (after the annihilation of that legion about
+A.D. 118) by the Sixth legion, it developed outside its walls a town of
+civil life, which later obtained Roman municipal rank and in the 4th
+century was the seat of a Christian bishop. The fortress and town were
+separated by the Ouse. On the left bank, where the minster stands, was
+the fortress, of which the walls can still be partly traced, and one
+corner (the so-called Multangular Tower) survives. The municipality
+occupied the right bank near the present railway station. The place was
+important for its garrison and as an administrative centre, and the town
+itself was prosperous, though probably never very large. The name is
+preserved in the abbreviated form Ebor in the official name of the
+archbishop of York, but the philological connexion between Eboracum and
+the modern name York is doubtful and has probably been complicated by
+Danish influence.     (F. J. H.)
+
+
+
+
+ECA DE QUEIROZ, JOSE MARIA (1843-1900), Portuguese writer, was born at
+the northern fishing town of Povoa de Varzim, his father being a retired
+judge. He went through the university of Coimbra, and on taking his
+degree in law was appointed Administrador de Concelho at Leiria, but
+soon tired of the narrow mental atmosphere of the old cathedral town and
+left it. He accompanied the Conde de Rezende to Egypt, where he assisted
+at the opening of the Suez Canal, and to Palestine, and on his return
+settled down to journalism in Lisbon and began to evolve a style, at
+once magical and unique, which was to renovate his country's prose.
+Though he spent much of his days with the philosopher sonneteer Anthero
+de Quental, and the critic Jayme Batalha Reis, afterwards consul-general
+in London, he did not restrict his intimacy to men of letters, but
+frequented all kinds of society, acquiring a complete acquaintance with
+contemporary Portuguese life and manners. Entering the consular service
+in 1872, he went to Havana, and, after a tour in the United States, was
+transferred two years later to Newcastle-on-Tyne and in 1876 to Bristol.
+In 1888 he became Portuguese consul-general in Paris, and there died in
+1900.
+
+Queiroz made his literary debut in 1870 by a sensational story, _The
+Mystery of the Cintra Road_, written in collaboration with the art
+critic Ramalho Ortigao, but the first publication which brought him fame
+was _The Farpas_, a series of satirical and humorous sketches of various
+phases of social life, which, to quote the poet Guerra Junqueiro,
+contain "the epilepsy of talent." These essays, the joint production of
+the same partners, criticized and ridiculed the faults and foibles of
+every class in turn, mainly by a comparison with the French, for the
+education of Queiroz had made him a Frenchman in ideas and sympathies.
+His Brazilian friend, Eduardo Prado, bears witness that at this period
+French literature, especially Hugo's verse, and even French politics,
+interested Queiroz profoundly, while he altogether ignored the
+_belles-lettres_ of his own country and its public affairs. This phase
+lasted for some years, and even when he travelled in the East he was
+inclined to see it with the eyes of Flaubert, though the publication of
+_The Relic_ and that delightful prose poem _Sweet Miracle_ afterwards
+showed that he had been directly impressed and deeply penetrated by its
+scenery, poetry and mysticism. The Franco-German War of 1870, however,
+by lowering the prestige of France, proved the herald of a national
+Portuguese revival, and had a great influence on Queiroz, as also had
+his friend Oliveira Martins (q.v.), the biographer of the patriot kings
+of the Aviz dynasty. He founded the Portuguese Realist-Naturalist
+school, of which he remained for the rest of his life the chief
+exponent, by a powerful romance, _The Crime of Father Amaro_, written in
+1871 at Leiria but only issued in 1875. Its appearance then led to a
+baseless charge that he had plagiarized _La Faute de l'Abbe Mouret_, and
+ill-informed critics began to name Queiroz the Portuguese Zola, though
+he clearly occupied an altogether different plane in the domain of art.
+During his stay in England he produced two masterpieces, _Cousin Basil_
+and _The Maias_, but they show no traces of English influence, nor again
+are they French in tone, for, living near to France, his disillusionment
+progressed and was completed when he went to Paris and had to live under
+the regime of the Third Republic. Settling at Neuilly, the novelist
+became chronicler, critic, and letter-writer as well, and in all these
+capacities Queiroz displayed a spontaneity, power and artistic finish
+unequalled in the literature of his country since the death of Garrett.
+A bold draughtsman, he excelled in freshness of imagination and careful
+choice and collocation of words, while his warmth of colouring and
+brilliance of language speak of the south. Many of his pages descriptive
+of natural scenery, such for instance as the episode of the return to
+Tormes in _The City and the Mountains_, have taken rank as classic
+examples of Portuguese prose, while as a creator of characters he stood
+unsurpassed by any writer of his generation in the same field. He
+particularly loved to draw and judge the middle class, and he mocks at
+and chastises its hypocrisy and narrowness, its veneer of religion and
+culture, its triumphant lying, its self-satisfied propriety, its cruel
+egotism. But though he manifested a predilection for middle-class types,
+his portrait gallery comprises men and women of all social conditions.
+_The Maias_, his longest book, treats of _fidalgos_, while perhaps his
+most remarkable character study is of a servant, Juliana, in _Cousin
+Basil_. At least two of his books, this latter and _The Crime of Father
+Amaro_, are _chroniques scandaleuses_ in their plots and episodes; these
+volumes, however, mark not only the high-water line of the
+Realist-Naturalist school in Portugal, but are in themselves, leaving
+aside all accidentals, creative achievements of a high order.
+
+Though Queiroz was a keen satirist of the ills of society, his pages
+show hardly a trace of pessimism. _The City and the Mountains_, and in
+part _The Relic_ also, reveal the apostle of Realism as an idealist and
+dreamer, a true representative of that Celtic tradition which survives
+in the race and has permeated the whole literature of Portugal. _The
+Mandarin_, a fantastic variation on the old theme of a man self-sold to
+Satan, and _The Illustrious House of Ramires_, are the only other
+writings of his that require mention, except _The Correspondence of
+Fradique Mendes_. In conjunction with Anthero de Quental and Jayme
+Batalha Reis, Queiroz invented under that name a smart man of the world
+who had something of himself and something of Eduardo Prado, and made
+him correspond on all sorts of subjects with imaginary friends and
+relatives to the delight of the public, many of whom saw in him a
+mysterious new writer whose identity they were eager to discover. These
+sparkling and humorous letters are an especial favourite with admirers
+of Queiroz, because they reveal so much of his very attractive
+personality, and perhaps the cleverest of the number, that on Pacheco,
+has received an English dress. In addition to his longer and more
+important works, Queiroz wrote a number of short stories, some of which
+have been printed in a volume under the title of _Contos_. The gems of
+this remarkable collection are perhaps _The Peculiarities of a
+Fair-haired Girl_, _A Lyric Poet_, _Jose Matthias_, _The Corpse_, and
+_Sweet Miracle_.
+
+  Most of his books have gone through many editions, and they are even
+  more appreciated in the Brazils than in Portugal. It should be
+  mentioned that the fourth edition of _Father Amaro_ is entirely
+  different in form and action from the first, the whole story having
+  been rewritten. One of Queiroz's romances and two of his short stories
+  have been published in English. An unsatisfactory version of _Cousin
+  Basil_, under the title _Dragon's Teeth_, appeared at Boston, U.S.A.,
+  in 1889, while _Sweet Miracle_ has had three editions in England and
+  one in America, and there is also a translation of _O Defunto_ (_The
+  Corpse_) under the name of _Our Lady of the Pillar_.
+
+  An admirable critical study of the work of Queiroz will be found in _A
+  Geracao Nova--Os Novellistas_, by J. Pereira de Sampaio (_Bruno_),
+  (Oporto, 1886). The _Revista moderna_ of the 20th of November 1897 was
+  entirely devoted to him. Senhor Batalha Reis gives interesting
+  reminiscences of the novelist's early days in his preface to some
+  prose fragments edited by him and named _Prosas Barbaras_ (Oporto,
+  1903).     (E. Pr.)
+
+
+
+
+ECARTE (Fr. for "separated," "discarded"), a game at cards, of modern
+origin, probably first played in the Paris _salons_ in the first quarter
+of the 19th century. It is a development of a very old card game called
+_la triomphe_ or _French-ruff_. Ecarte is generally played by two
+persons, but a pool of three may be formed, the player who is out taking
+the place of the loser, and the winner of two consecutive games winning
+the pool. At French ecarte (but not at English) bystanders who are
+betting may advise the players, but only by pointing to the cards they
+desire them to play, and the loser of the game goes out, one of the
+_rentrants_ taking his place, unless the loser is playing _la chouette_,
+i.e. playing single-handed against two, and taking all bets.
+
+The small cards (from the two to the six, both inclusive) are removed
+from an ordinary pack. The players cut for deal, the highest having the
+choice. The king is the highest card, the ace ranking after the knave.
+The dealer gives five cards to his adversary, and five to himself, by
+two at a time to each and by three at a time to each, or vice versa. The
+eleventh card is turned up for trumps. If it is a king, the dealer
+scores one, at any time before the next deal. The non-dealer then looks
+at his cards. If satisfied with them he plays, and there is no
+discarding; if not satisfied he "proposes." The dealer may either accept
+or refuse. If he accepts, each player discards face downwards as many
+cards as he thinks fit, and fresh ones are given from the undealt cards
+or "stock," first to complete the non-dealer's hand to five, then to
+complete the dealer's. To ask for "a book" is to ask for five cards.
+Similarly a second proposal may be made, and so on, until one player is
+satisfied with his hand. If the dealer refuses, the hand is played
+without discarding. If the non-dealer announces that he holds the king
+of trumps, he scores one; and similarly, if the dealer holds the king
+and announces it, he scores one. The announcement must be made before
+playing one's first card, or if that card be the king, on playing it.
+The non-dealer, being satisfied with his hand, leads a card. The dealer
+plays a card to it, the two cards thus played forming a trick. The
+winner of the trick leads to the next, and so on. The second to play to
+a trick must follow suit if able, and must win the trick if he can.
+
+The scores are for the king and for the majority of tricks. The player
+who wins three tricks scores one for the "point"; if he wins all five
+tricks, he scores two for the "vole." If the non-dealer plays without
+proposing, or the dealer refuses the first proposal, and fails to win
+three tricks, the adversary scores two, but no more even if he wins the
+vole. The game is five up. The points are conveniently marked with a
+three-card and a two-card, as at euchre. The three is put face upwards
+with the two face downwards on the top of it. When one or two or three
+points are scored the top card is moved so as to expose them. At four,
+one pip of the two-card is put under the other card. Games may be
+recorded similarly.
+
+  _Hints to Players._--The following hints may be of service to
+  beginners:--
+
+  Shuffle thoroughly after every deal.
+
+  Do not announce the king until in the act of playing your first card.
+
+  The hands which should be played without proposing, called _jeux de
+  regle_ (standard hands), ought to be thoroughly known. They are as
+  follows:--
+
+  1. All hands with three or more trumps, whatever the other cards.
+
+  2. Hands with _two trumps_ which contain also--
+
+    (a) Any three cards of one plain suit;
+
+    (b) Two cards of one plain suit, one being as high as a queen;
+
+    (c) Two small cards of one suit, the fifth card being a king of
+    another suit;
+
+    (d) Three high cards of different suits.
+
+  3. Hands with _one trump_, which contain also--
+
+    (a) King, queen, knave of one suit, and a small card of another;
+
+    (b) Four cards of one suit headed by king;
+
+    (c) Three cards of one suit headed by queen, and queen of another
+    suit.
+
+  4. Hands with _no trump_, which contain three queens or cards of equal
+  value in different suits, e.g., four court cards.
+
+  5. Hands from which only two cards can be discarded without throwing a
+  king or a trump.
+
+  Holding cards which make the point certain, propose. If you hold a
+  _jeu de regle_, and one of the trumps is the king, propose, as your
+  adversary cannot then take in the king.
+
+  When discarding, throw out all cards except trumps and kings.
+
+  If your adversary proposes you should accept, unless you are guarded
+  in three suits (a queen being a sufficient guard), or in two suits
+  with a trump, or in one suit with two trumps. Hence the rule not to
+  discard two cards, unless holding the king of trumps, applies to the
+  dealer.
+
+  The hands with which to refuse are the same as those with which to
+  play without proposing, except as follows:--
+
+  1. Two trumps and three cards of one plain suit should not be played
+  unless the plain suit is headed by a court card.
+
+  2. One trump and a tierce major is too weak, unless the fifth card is
+  a court card. With similar hands weaker in the tierce major suit,
+  accept unless the fifth card is a queen.
+
+  3. One trump and four cards of a plain suit is too weak to play.
+
+  4. One trump and two queens is too weak, unless both queens are singly
+  guarded.
+
+  5. One trump, queen of one suit, and knave guarded of another should
+  not be played unless the queen is also guarded, or the card of the
+  fourth suit is a court card.
+
+  6. One trump, a king and a queen, both unguarded, should not be
+  played, unless the fourth suit contains a card as high as an ace.
+
+  7. Four court cards without a trump are too weak to play, unless they
+  are of three different suits.
+
+  Refuse with three queens, if two are singly guarded; otherwise,
+  accept.
+
+  Lead from your guarded suit, and lead the highest.
+
+  If the strong suit led is not trumped, persevere with it, unless with
+  king of trumps, or queen (king not having been announced), or knave
+  ace, when lead a trump before continuing your suit.
+
+  You should not lead trumps at starting, unless you hold king or queen,
+  knave, or knave ace, with court cards out of trumps.
+
+  The score has to be considered. If the dealer is at four, and the king
+  is not in your hand nor turned up, play any cards without proposing
+  which give an even chance of three tricks, e.g. a queen, a guarded
+  knave, and a guarded ten. The same rule applies to the dealer's
+  refusal.
+
+  At the adverse score of four, and king not being in hand or turned up,
+  any hand with one trump should be played, unless the plain cards are
+  very small and of different suits.
+
+  If the non-dealer plays without proposing when he is four to three,
+  and the dealer holds the king he ought not to mark it. The same rule
+  applies to the non-dealer after a refusal, if the dealer is four to
+  three.
+
+  At the score of non-dealer three, dealer four, the dealer should
+  refuse on moderate cards, as the player proposing at this score must
+  have a very bad hand.
+
+  At four a forward game should not be played in trumps, as there is no
+  advantage in winning the vole.
+
+  _Laws of Ecarte._--The following laws are abridged from the revised
+  code adopted by the Turf Club:--A cut must consist of at least two
+  cards. Card exposed in cutting, fresh cut. Order of distribution of
+  cards, whether by three and two, or vice versa, once selected, dealer
+  must not change it during game. Player announcing king when he has not
+  got it, and playing a card without declaring error, adversary may
+  correct score and have hand played over again. If offender wins point
+  or vole that hand, he scores one less than he wins. Proposal,
+  acceptance, or refusal made cannot be retracted. Cards discarded must
+  not be looked at. Cards exposed in giving cards to non-dealer, he has
+  option of taking them or of having next cards; dealer exposing his own
+  cards, no penalty. Dealer turning up top card after giving cards,
+  cannot refuse second discard. Dealer accepting when too few cards in
+  stock to supply both, non-dealer may take cards, and dealer must play
+  his hand. Card led in turn cannot be taken up again. Card played to a
+  lead can only be taken up prior to another lead, to save revoke or to
+  correct error of not winning trick. Card led out of turn may be taken
+  up prior to its being played to. Player naming one suit and leading
+  another, adversary has option of requiring suit named to be led. If
+  offender has none, no penalty. Player abandoning hand, adversary is
+  deemed to win remaining tricks, and scores accordingly. If a player
+  revokes or does not win trick when he can do so, the adversary may
+  correct score and have hand replayed.
+
+  See _Academie des jeux_ (various editions after the first quarter of
+  the 19th century); Hoyle's _Games_ (various editions about the same
+  dates); Ch. Van-Tenac et Louis Delanoue, _Traite du jeu de l'ecarte_
+  (Paris, 1845; translated in Bohn's _Handbook of Games_, London, 1850);
+  "Cavendish," _The Laws of Ecarte, adopted by the Turf Club, with a
+  Treatise on the Game_ (London, 1878); _Pocket Guide to Ecarte_
+  ("Cavendish," 1897); Foster's _Encyclopaedia of Indoor Games_ (1903).
+
+
+
+
+ECBATANA (_Agbatana_ in Aeschylus, _Hangmatana_ in Old Persian, written
+_Agamtanu_ by Nabonidos, and _Agamatanu_ at Behistun, mod. _Hamadan_),
+the capital of Astyages (Istuvegu), which was taken by Cyrus in the
+sixth year of Nabonidos (549 B.C.). The Greeks supposed it to be the
+capital of Media, confusing the Manda, of whom Astyages was king, with
+the Mada or Medes of Media Atropatene, and ascribed its foundation to
+Deioces (the _Daiukku_ of the cuneiform inscriptions), who is said to
+have surrounded his palace in it with seven concentric walls of
+different colours. Under the Persian kings, Ecbatana, situated at the
+foot of Mount Elvend, became a summer residence; and was afterwards the
+capital of the Parthian kings. Sir H. Rawlinson attempted to prove that
+there was a second and older Ecbatana in Media Atropatene, on the site
+of the modern Takht-i-Suleiman, midway between Hamadan and Tabriz
+(_J.R.G.S._ x. 1841), but the cuneiform texts imply that there was only
+one city of the name, and Takht-i-Suleiman is the Gazaca of classical
+geography. The Ecbatana at which Cambyses is said by Herodotus (iii. 64)
+to have died is probably a blunder for Hamath.
+
+  See Perrot and Chipiez, _History of Art in Persia_ (Eng. trans.,
+  1892); M. Dieulafoy, _L'Art antique de la Perse_, pt. i. (1884); J. de
+  Morgan, _Mission scientifique en Perse_, ii. (1894). See HAMADAN and
+  PERSIA: _Ancient History_, Sec. v. 2.     (A. H. S.)
+
+
+
+
+ECCARD, JOHANN (1553-1611), German composer of church music, was born at
+Muehlhausen on the Unstrut, Prussia, in 1553. At the age of eighteen he
+went to Munich, where he became the pupil of Orlando Lasso. In his
+company Eccard is said to have visited Paris, but in 1574 we find him
+again at Muehlhausen, where he resided for four years, and edited,
+together with Johann von Burgk, his first master, a collection of sacred
+songs, called _Crepundia sacra Helmboldi_ (1577). Soon afterwards he
+obtained an appointment as musician in the house of Jacob Fugger, the
+Augsburg banker. In 1583 he became assistant conductor, and in 1599
+conductor, at Koenigsberg, to Georg Friedrich, margrave of
+Brandenburg-Anspach, the administrator of Prussia. In 1608 he was called
+by the elector Joachim Friedrich to Berlin as chief conductor, but this
+post he held only for three years, owing to his premature death at
+Koenigsberg in 1611. Eccard's works consist exclusively of vocal
+compositions, such as songs, sacred cantatas and chorales for four or
+five, and sometimes for seven, eight, or even nine voices. Their
+polyphonic structure is a marvel of art, and still excites the
+admiration of musicians. At the same time his works are instinct with a
+spirit of true religious feeling. His setting of the beautiful words
+"Ein' feste Burg ist unser Gott" is still regarded by the Germans as
+their representative national hymn. Eccard and his school are
+inseparably connected with the history of the Reformation.
+
+  Of Eccard's songs a great many collections are extant; see K.G.A. von
+  Winterfeld, _Der Evangelische Kirchengesang_ (1843); Doering
+  (_Choralkunde_, p. 47).
+
+
+
+
+ECCELINO [or EZZELINO] DA ROMANO (1194-1259), Ghibelline leader, and
+supporter of the emperor Frederick II., was born on the 25th of April
+1194. He belonged to a family descended from a German knight named
+Eccelin, who followed the emperor Conrad II. to Italy about 1036, and
+received the fief of Romano near Padua. Eccelin's grandson was Eccelino
+III., surnamed the Monk, who divided his lands between his two sons in
+1223, and died in 1235. The elder of these two sons was Eccelino, who in
+early life began to take part in family and other feuds, and in 1226, at
+the head of a band of Ghibellines, seized Verona and became _podesta_ of
+the city. He soon lost Verona, but regained it in 1230; and about this
+time came into relations with Frederick II., who in 1232 issued a
+charter confirming him in his possessions. In 1236 when besieged in
+Verona he was saved by the advance of the emperor, who in November of
+the same year took Vicenza and entrusted its government to Eccelino. In
+1237 he obtained authority over Padua and Treviso; and on the 27th of
+November in that year he shared in the victory gained by the emperor
+over the Lombards at Cortenuova. In 1238 he married Frederick's natural
+daughter, Selvaggia; in 1239 was appointed imperial vicar of the march
+of Treviso; but in the same year was excommunicated by Pope Gregory IX.
+He was constantly engaged in increasing his possessions; was present at
+the siege of Parma in 1247, and after Frederick's death in 1250 he
+supported his son, the German king Conrad IV. His cruelties had,
+however, aroused general disgust, and in 1254 he was again
+excommunicated. In 1256 Pope Alexander IV. proclaimed a crusade against
+him, and a powerful league was soon formed under the leadership of
+Philip, archbishop of Ravenna. Padua was taken from Eccelino, but on the
+1st of September 1258 he defeated his enemies at Torricella. He then
+made an attempt on Milan, and the rival forces met at Cassano on the
+27th of September 1259, when Eccelino was wounded and taken prisoner.
+Enraged at his capture, he tore the bandages from his wounds, refused to
+take nourishment, and died at Soncino on the 7th of October 1259. In the
+following year his brother Albert was put to death, and the Romano
+family became extinct. Eccelino, who is sometimes called the _tyrant_,
+acquired a terrible reputation on account of his cruelties, a reputation
+that won for him the immortality of inclusion in Dante's _Inferno_; but
+his unswerving loyalty to Frederick II. forms a marked contrast to the
+attitude of many of his contemporaries.
+
+Eccelino is the subject of a novel by Cesare Cantu and of a drama by J.
+Eichendorff.
+
+  See J.M. Gittermann, _Ezzelino da Romano_ (Freiburg, 1890); S. Mitis,
+  _Storia d' Ezzelino IV. da Romano_ (Maddaloni, 1896); and F. Stieve,
+  _Ezzelino von Romano_ (Leipzig, 1909).
+
+
+
+
+ECCENTRIC (from Gr. [Greek: ek], out of, and [Greek: kentron], centre),
+literally "out from the centre," and thus used to connote generally any
+deviation from the normal. In astronomy the word denotes a circle round
+which a body revolves, but whose centre is displaced from the visible
+centre of motion. In the ancient astronomy the ellipses in which it is
+now known that the planets revolve around the sun could not be
+distinguished from circles, but the unequal angular motion due to
+ellipticity was observed. The theory of the eccentric was that the
+centre of the epicycle of each planet moved uniformly in a circle, the
+centre of which was displaced from that of the earth by an amount double
+the eccentricity of the actual ellipse, as the case is now understood.
+When measured around this imaginary centre, which is so situated on the
+major axis of the ellipse that the focus, or place of the real sun, is
+midway between it and the centre of the ellipse, the motion is
+approximately uniform. In engineering, an eccentric is a mechanical
+device for converting rotary into reciprocating motion (see
+STEAM-ENGINE). For eccentric angle see ELLIPSE.
+
+
+
+
+ECCHELLENSIS (or ECHELLENSIS), ABRAHAM (d. 1664), a learned Maronite,
+whose surname is derived from Eckel in Syria, where he was born towards
+the close of the 16th century. He was educated at the Maronite college
+in Rome, and, after taking his doctor's degree in theology and
+philosophy, returned for a time to his native land. He then became
+professor of Arabic and Syriac in the college of the Propaganda at Rome.
+Called to Paris in 1640 to assist Le Jay in the preparation of his
+polyglot Bible, he contributed to that work the Arabic and Latin
+versions of the book of Ruth and the Arabic version of the third book of
+Maccabees. In 1646 he was appointed professor of Syriac and Arabic at
+the College de France. Being invited by the Congregation of the
+Propaganda to take part in the preparation of an Arabic version of the
+Bible, Ecchellensis went again in 1652 or 1653 to Rome. He published
+several Latin translations of Arabic works, of which the most important
+was the _Chronicon Orientale_ of Ibnar-Rahib (Paris, 1653), a history of
+the patriarchs of Alexandria. He was engaged in an interesting
+controversy with John Selden as to the historical grounds of episcopacy,
+in the course of which he published his _Eutychius vindicatus, sive
+Responsio ad Seldeni Origines_ (Rome, 1661). Conjointly with Giovanni
+Borelli he wrote a Latin translation of the 5th, 6th and 7th books of
+the _Conics_ of Apollonius of Perga (1661). He died at Rome in 1664.
+
+
+
+
+ECCLES, a municipal borough in the Eccles parliamentary division of
+Lancashire, England, 4 m. W. of Manchester, of which it forms
+practically a suburb. Pop. (1901) 34,369. It is served by the London &
+North-Western railway and by the Birkenhead railway (North-Western and
+Great Western joint). The Manchester Ship Canal passes through. The
+church of St Mary is believed to date from the 12th century, but has
+been enlarged and wholly restored in modern times. There are several
+handsome modern churches and chapels, a town hall, and numerous cotton
+mills, while silk-throwing and the manufacture of fustians and ginghams
+are also among the industries, and there are also large engine works. A
+peculiar form of cake is made here, taking name from the town, and has a
+wide reputation. Eccles was incorporated in 1892, and the corporation
+consists of a mayor, 6 aldermen and 18 councillors. The borough
+maintains the tramway service, &c., but water and gas are supplied from
+Manchester and Salford respectively. Area, 2057 acres.
+
+Before the Reformation the monks of Whalley Abbey had a grange here at
+what is still called Monks' Hall; and in 1864 many thousands of silver
+pennies of Henry III. and John of England and William I. of Scotland
+were discovered near the spot. Robert Ainsworth, the author of the Latin
+and English dictionary so long familiar to English students, was born at
+Eccles in 1660; and it was at the vicarage that William Huskisson
+expired on the 15th of September 1830 from injuries received at the
+opening of the Liverpool & Manchester railway. From early times "wakes"
+were held at Eccles, and bull-baiting, bear-baiting and cock-fighting
+were carried on. Under Elizabeth these festivals, which had become
+notoriously disorderly, were abolished, but were revived under James I.,
+and maintained until late in the 19th century on public ground. The
+cockpit remained on the site of the present town hall. A celebration on
+private property still recalls these wakes.
+
+
+
+
+ECCLESFIELD, a township in the Hallamshire parliamentary division of the
+West Riding of Yorkshire, England, 5 m. N. of Sheffield, on the Great
+Central and Midland railways. The church of St Mary is Perpendicular,
+with a central tower, and contains excellent woodwork. It formerly bore,
+and must have deserved, the familiar title of the "Minster of the
+Moors." Ecclesfield was the seat of a Benedictine priory, which passed
+to the Carthusians in the 14th century. Cutlery and tools are largely
+manufactured, and there are coal-mines, paper mills and iron and
+fire-clay works. After the inclusion within the county borough of
+Sheffield of part of the civil parish of Ecclesfield in 1901, the
+population was 18,324.
+
+
+
+
+ECCLESHALL, a market town in the north-western parliamentary division of
+Staffordshire, England; 7 m. N.W. from Stafford, and 4 W. of Norton
+Bridge station on the London & North-Western main line. Pop. (1901)
+3799. The church of the Holy Trinity, one of the most noteworthy in
+Staffordshire, is principally Early English, and has fine stained glass.
+Several bishops of Lichfield are buried here, as Eccleshall Castle was
+the episcopal residence from the 13th century until 1867. Of this the
+ancient remains include a picturesque tower and bridge. To the west on
+the borders of Shropshire is Blore Heath, the scene of a defeat of the
+Lancastrians by the Yorkists in 1459.
+
+
+
+
+ECCLESIA (Gr. [Greek: ekklesia], from [Greek: ek], out, and [Greek:
+kalein], to call), in ancient Athens, the general assembly of all the
+freemen of the state. In the primitive unorganized state the king was
+theoretically absolute, though his great nobles meeting in the Council
+(see BOULE) were no doubt able to influence him considerably. There is,
+however, no doubt that in the earliest times the free people, i.e. the
+fighting force of the state, were called together to ratify the
+decisions of the king, and that they were gradually able to enforce
+their wishes against those of the nobles. In Athens, as in Rome, where
+the Plebs succeeded in their demand for the codification of the laws
+(the Twelve Tables), it was no doubt owing to the growing power of the
+people meeting in the Agora that Draco was entrusted with the task of
+publishing a code of law and so putting an end to the arbitrary
+judicature of the aristocratic party. But there is no evidence that the
+Ecclesia had more than a _de facto_ existence before Solon's reforms.
+
+The precise powers which Solon gave the people are not known. It is
+clear that the executive power in the state (see ARCHON) was still
+vested in the Eupatrid class. It is obvious, therefore, that a moderate
+reformer would endeavour to give to the people some control over the
+magistracy. Now in speaking of the Thetes (the lowest of the four
+Solonian classes; see SOLON), Aristotle's _Constitution of Athens_ says
+that Solon gave them merely "a share in the Ecclesia and the Law
+Courts," and in the _Politics_ we find that he gave them the right of
+electing the magistrates and receiving their accounts at the end of the
+official year. Thus it seems that the "mixed" character of Solon's
+constitution consisted in the fact that though the officials of the
+state were still necessarily Eupatrid, the Ecclesia elected those of the
+Eupatrids whom they could trust, and further had the right of
+criticizing their official actions. Secondly, all our accounts agree
+that Solon admitted the Thetes to the Ecclesia, thus recognizing them as
+citizens. Under Cleisthenes the Ecclesia remained the sovereign power,
+but the Council seems to have become to some extent a separate
+administrative body. The relation of Boule and Ecclesia in the
+Cleisthenic democracy was of the greatest importance. The Ecclesia
+alone, a heterogeneous body of untrained citizens, could not have
+passed, nor even have drawn up intelligible measures; all the
+preliminary drafting was done by the small committee of the Boule which
+was in session at any particular time. In the 5th century the functions
+of the Ecclesia and the popular courts of justice were vastly increased
+by the exigencies of empire. At the beginning of the 4th century B.C.
+the system of payment was introduced (see below). In 308 B.C. Demetrius
+of Phalerum curtailed the power of the Ecclesia by the institution of
+the _Nomophylaces_ (Guardians of the Law), who prevented the Ecclesia
+from voting on an illegal or injurious motion. Under Roman rule the
+powers of the Ecclesia and the popular courts were much diminished, and
+after 48 B.C. (the franchise being frequently sold to any casual alien)
+the Demos (people) was of no importance. They still assembled to pass
+psephisms in the theatre and to elect strategi, and, under Hadrian, had
+some small judicial duties, but as a governing body the Ecclesia died
+when Athens became a _civitas libera_ under Roman protection.
+
+_Constitution and Functions._--Throughout the period of Athenian
+greatness the Ecclesia was the sovereign power, not only in practice but
+also in theory. The assembly met in early times near the sanctuary of
+Aphrodite Pandemus (i.e. south of the Acropolis), but, in the 5th and
+4th centuries, the regular place of meeting was the Pnyx. From the 5th
+century it met sometimes in the theatre, which in the 3rd century was
+the regular place. From Demosthenes we learn that in his time special
+meetings were held at Peiraeus, and, in the last centuries B.C.,
+meetings were held at Athens and Peiraeus alternately. Certain meetings,
+however, for voting ostracism (q.v.) and on questions affecting
+individual status took place in the Agora. Meetings were (1) ordinary,
+(2) extraordinary, and (3) convened by special messengers ([Greek:
+kyriai], [Greek: synkletoi] and [Greek: katakletoi]), these last being
+called when it was desirable that the country people should attend. At
+ordinary meetings the attendance was practically confined to Athenian
+residents. According to Aristotle there were four regular meetings in
+each prytany (see BOULE); probably only the first of these was called
+[Greek: kyria]. It is certain, however, that the four meetings did not
+fall on regular days, owing to the occurrence of feast days on which no
+meeting could take place. In the [Greek: kyria ekklesia] of each month
+took place the _Epicheirotonia_ (monthly inquiry) of the state
+officials, and if it proved unsatisfactory a trial before the Heliaea
+was arranged; the council reported on the general security and the
+corn-supply, and read out lists of vacant inheritances and unmarried
+heiresses. In the sixth prytany of each year at the [Greek: kyria
+ekklesia] the question whether ostracism should take place that year was
+put to the vote. For all meetings it was usual that the Prytaneis should
+give five days' notice in the form of a _programma_ (agenda). On
+occasions of sudden importance the herald of the council summoned the
+people with a trumpet, and sometimes special messengers were despatched
+to "bring in" the country people ([Greek: katakalein]).
+
+After the archonship of Solon all Athenians over the age of eighteen
+were eligible to attend the assembly, save those who for some reason had
+suffered _atimia_ (loss of civil rights). To prevent the presence of any
+disqualified persons, six _lexiarchs_ with thirty assistants were
+present with the deme-rolls in their hands. These officers superintended
+the payment in the 4th century and probably the _toxotae_ (police) also,
+whose duty it was before the introduction of pay to drive the people out
+of the Agora into the Ecclesia with a rope steeped in red dye which they
+stretched out and used as a draw net (see Aristoph. _Acharn._ 22 and
+_Eccles._ 378). The introduction of pay, which belongs to the early
+years of the 4th century and by the _Constitution_ (c. 41 ad fin.) is
+attributed to Agyrrhius, a statesman of the restored democracy, was a
+device to secure a larger attendance. The rate rose from one to two
+obols and then to three obols (Aristoph. _Eccles._ 300 sqq.), while at
+the time of Aristotle it was one and a half drachmas for the [Greek:
+kyria ekklesia] and one drachma for other meetings. Probably those who
+were late did not receive payment.
+
+_Procedure._--The proceedings opened with formalities: the purification
+by the _peristiarchs_, who carried round slain sucking pigs; the curse
+against all who should deceive the people; the appointment (in the 4th
+century) of the _proedri_ and their _epistates_ (see BOULE); the report
+as to the weather-omens. The assembly was always dismissed if there were
+thunder, rain or an eclipse. These formalities over, the Prytaneis
+communicated the _probouleuma_ of the council, without which the
+Ecclesia could not debate. This recommendation either submitted definite
+proposals or merely brought the agenda before the assembly. Its
+importance lay largely in the fact that it _explained_ the business in
+hand, which otherwise must often have been beyond the grasp of a
+miscellaneous assembly. After the reading, a preliminary vote was taken
+as to whether the council's report should be accepted _en bloc_. If it
+was decided to discuss, the herald called upon people to speak. Any
+person, without distinction of age or position, might obtain leave to
+speak, but it seems probable that the man who had moved the
+recommendation previously in the council would advocate it in the
+assembly. The council was, therefore, a check on the assembly, but its
+powers were to some extent illusory, because any member of the assembly
+(1) might propose an amendment, (2) might draw up a new resolution
+founded on the principal motion, (3) might move the rejection of the
+motion and the substitution of another, (4) might bring in a motion
+asking the council for a recommendation on a particular matter, (5)
+might petition the council for leave to speak on a given matter to the
+assembly. Voting usually was by show of hands, but in special cases
+(ostracism, &c.) by ballot (i.e. by casting pebbles into one of two
+urns). The decision of the assembly was called a _psephism_ and had
+absolute validity. These decisions were deposited in the Metrooen where
+state documents were preserved; peculiarly important decrees were
+inscribed also on a column (_stele_) erected on the Acropolis. It has
+been shown that the power of the council was far from sufficient. The
+real check on the vagaries of amateur legislators was the Graphe
+Paranomon. Any man was at liberty to give notice that he would proceed
+against the mover of a given resolution either before or after the
+voting in the Ecclesia. A trial in a Heliastic court was then arranged,
+and the plaintiff had to prove that the resolution in question
+contravened an existing law. If this contention were upheld by the
+court, when the case was brought to it by the Thesmothetae, the
+resolution was annulled, and the defendant had to appear in a new trial
+for the assessment of the penalty, which was usually a fine, rarely
+death. Three convictions under this law, however, involved a certain
+loss of rights; the loser could no longer move a resolution in the
+Ecclesia. After the lapse of a year the mover of a resolution could not
+be attacked. In the 4th century the Graphe Paranomon took the place of
+Ostracism (q.v.). In the 5th century it was merely an arrangement
+whereby the people sitting as sworn juries ratified or annulled their
+own first decision in the Ecclesia.
+
+_Revision of Laws._--In the 4th century, the assembly annually, on the
+eleventh day of Hecatombaeon (the first day of the official year), took
+a general vote on the laws, to decide whether revision was necessary. If
+the decision was in favour of alteration, it was open to any private
+citizen to put up notice of amendments. The Nomothetae, a panel selected
+by the Prytaneis from the Heliaea, heard arguments for and against the
+changes proposed and voted accordingly. Against all new laws so passed,
+there lay the Graphe; Paranomon. Thus the Nomothetae, not the Ecclesia,
+finally passed the law.
+
+_Judicial Functions._--The Ecclesia heard cases of Probole and
+Eisangelia (see GREEK LAW). The Probole was an action against sycophants
+and persons who had not kept their promises to the people, or had
+disturbed a public festival. The verdict went by show of hands, but no
+legal consequences ensued; if the plaintiff demanded punishment he had
+to go to the Heliaea which were not at all bound by the previous vote in
+the Ecclesia. Cases of Eisangelia in which the penalty exceeded the
+legal competence of the council came before the Ecclesia in the form of
+a _probouleuma_. To prevent vexatious accusations, it was (at some date
+unknown) decided that the accuser who failed to obtain one-fifth of the
+votes should be fined 1000 drachmas (L40). (For the procedure in case of
+OSTRACISM see that article.)
+
+_Summary._--Thus it will be seen that the Ecclesia, with no formal
+organization, had absolute power save for the Graphe Paranomon (which,
+therefore, constituted the dicasteries in one sense the sovereign power
+in the state). It dealt with all matters home and foreign. Every member
+could initiate legislation, and, as has been shown, the power of the
+council was merely formal. As against this it must be pointed out that
+it was by no means a representative assembly in practice. The phrase
+used to describe a very special assembly ([Greek: katakletos ekklesia])
+shows that ordinarily the country members did not attend ([Greek:
+katakalein] always involving the idea of motion from a distance towards
+Athens), and Thucydides says that 5000 was the maximum attendance,
+though it must be remembered that he is speaking of the time when the
+number of citizens had been much reduced owing to the plague and the
+Sicilian expedition. From this we understand the necessity of payment in
+the 4th century, although in that period the Ecclesia was supreme
+(_Constitution of Athens_, xli. 2). The functions of the Ecclesia thus
+differed in two fundamental respects from those which are in modern
+times associated with a popular assembly. (1) It did not exercise, at
+least in the period as to which we are best instructed, the power of
+law-making ([Greek: nomothesia]) in the strict sense. It must be
+remembered, however, in qualification of this statement that it
+possessed the power of passing _psephismata_ which would in many cases
+be regarded as law in the modern sense. (2) The Ecclesia was principally
+concerned with the supervision of administration. Much of what we regard
+as executive functions were discharged by the Ecclesia.
+
+  With this article compare those on SOLON; BOULE; AREOPAGUS; GREEK LAW,
+  and, for other ancient popular assemblies, APELLA; COMITIA. See also
+  A.H.J. Greenidge, _Handbook of Greek Constitutional History_ (1896);
+  Gilbert, _Greek Constitutional Antiquities_ (trans. Brooks and
+  Nicklin, 1895); Schoemann, _De comitiis Atheniensium_; L. Schmidt, "De
+  Atheniensis reipublicae indole democratica" in _Ind. Lect._ (Marburg,
+  1865); J.W. Headlam, _Election by Lot at Athens_ (Cambridge, 1891).
+  See also the histories of Greece by Meyer, Busolt, Grote, Evelyn
+  Abbott, and J.E. Sandys' edition of the _Constitution of Athens_
+  (1892); for a comparative study, E.A. Freeman, _Comparative Politics_.
+       (J. M. M.)
+
+
+
+
+ECCLESIASTES (Heb. [Hebrew: Kohelet], _Kohelet_, "Koheleth"; Sept.
+[Greek: ekklesiastes]; Jerome _concionator_), one of the Wisdom Books of
+the Old Testament (see WISDOM LITERATURE). The book, as it stands, is a
+collection of the discourses, observations and aphorisms of a sage
+called Koheleth, a term the precise meaning of which is not certain. The
+Greek _ecclesiastes_ means one who takes part in the deliberations of an
+assembly (_ecclesia_), a debater or speaker in an assembly (Plato,
+_Gorgias_, 452 E), and this is the general sense of the Hebrew word. Its
+form (singular feminine) has been supposed to be the adoption or
+imitation of the Arabic employment of a fem. sing. as the designation of
+a high official person, as is the case in the title _caliph_ (whence the
+rendering in the margin of the Revised Version, "Great orator"); but the
+adoption of an Arabic idiom is not probable. This usage is not Hebrew;
+it is not found either in the Old Testament or in the later (Mishnaic)
+Hebrew. The form may have been suggested by that of the Hebrew word for
+"wisdom." _Koheleth_, however, is employed in the book not as a title of
+wisdom (for "wisdom" is never the speaker), but as the independent name
+of the sage. It is intended to represent him as a member of an assembly
+(_Kahal_)--not the Jewish congregation, but a body of students or
+inquirers, such as is referred to in xii. 9-11, a sort of collegium, of
+which he was the head; and as instructor of this body he gives his
+criticism of life. The author begins, indeed, with identifying his sage
+with King Solomon (i. 12-ii. 11, 12b); but he soon abandons this
+literary device, and speaks in his own name. The rendering "preacher"
+has a misleading connotation.
+
+In the book as we have it there is no orderly exposition of a theory; it
+rather has the appearance of a collection of remarks jotted down by a
+pupil (somewhat after the manner of Xenophon's _Memorabilia_), or of
+extracts from a sage's notebook. It is, however, characterized
+throughout (except in some scribal additions) by a definite thought, and
+pervaded by a definite tone of feeling. The keynote is given in the
+classic phrase with which the discussion opens and with which it closes:
+"Vanity of vanities (i.e. absolute vanity), all[1] is vanity!" Life,
+says the author, has nothing of permanent value to offer. His attitude
+is one not of bitterness but of calm hopelessness, with an occasional
+tinge of disgust or contempt. He fancies that he has tried or observed
+everything in human experience, and his deliberate conclusion is that
+nothing is worth doing. He believes in an all-powerful but indifferent
+God, and is himself an observer of society, standing aloof from its
+passions and ambitions, and interested only in pointing out their
+emptiness.
+
+This general view is set forth in a number of particular observations.
+
+1. His fundamental proposition is that there is a fixed, unchangeable
+order in the world, a reign of inflexible law (i. 4-11, iii. 1-11, 14,
+15, vii. 13, viii. 5-9): natural phenomena, such as sunrise and sunset,
+recur regularly; for everything in human experience a time has been set;
+birth and death, building up and destroying, laughing and weeping,
+silence and speech, love and hate, war and peace, are to be regarded not
+as utterances of a living, self-directing world, but as incidents in the
+work of a vast machine that rolls on for ever; there is an endless
+repetition--nothing is new, nothing is lost; if one thinks he has found
+something new, inquiry shows that it was in existence long ago; God, the
+author of all, seeks out the past in order to make it once more present;
+it is impossible to add to or take from the content of the world,
+impossible to change the nature of things, to effect any radical
+betterment of life; the result is unspeakable weariness--a depressing
+series of sights and sounds. No goal or purpose is discoverable in this
+eternal round; if the sun rises and goes on his journey through the sky,
+it is merely to come back to the place where he rose; rivers flow for
+ever into the sea without filling it. To what end was the world created?
+It is impossible to say. Such is Koheleth's view of life, and it is
+obvious that such a conception of an aimless cosmos is thoroughly
+non-Jewish, if we may judge Jewish thought by the great body of the
+extant literature.
+
+2. Further, says Koheleth, man is impelled to study the world, but under
+the condition that he shall never comprehend it (iii. 11, vii. 23, 24,
+viii. 16, 17). As to the meaning of the Hebrew term _olam_ in iii. 11,
+there are various opinions, but "world" appears to be the rendering
+favoured by the connexion: "God has made everything beautiful in its
+time, and has put the _olam_ into men's minds, yet so that they cannot
+understand His work": the _olam_, the sum of phenomena, is God's work.
+The word is not found in this sense elsewhere in the Old Testament, but
+it so occurs in the Mishna (_Pirke Aboth_, iv. 7), and the vocabulary of
+Ecclesiastes is admittedly similar to that of the Mishna. Only here in
+the Old Testament does it stand as a simple isolated noun; elsewhere it
+is the definition of a noun (in "everlasting covenant," &c.), or it is
+preceded by a preposition, in the phrases "for ever," "of old," or it
+stands alone (sing. or plur.) in the same adverbial sense, "for ever."
+The word means first a remote point in past or future, then a future
+point without limit of time, then a period of history, and finally the
+world considered as a mass of human experiences (cf. [Greek: aion]). The
+renderings "eternity" and "future" in the present passage are
+unsatisfactory; the former has an inappropriate metaphysical
+connotation, and yields no distinct sense; the latter does not suit the
+connexion, though there is reference to the future elsewhere (ix. 1).
+God, the text here declares, has made the world an object of man's
+thought, yet so that man can never find out the work that God has done
+(iii. 11). The reference seems to be not so much to the variety and
+complexity of phenomena as to the impossibility of construing them
+rationally or in such a way that man may foresee and provide for his
+future. Man is in the clutches of fate (ix. 11, 12): there is no
+observable relation between exertion and result in life: the race is not
+to the swift nor the battle to the strong; success does not attend
+wisdom, knowledge and skill; men are like fish taken in a net or birds
+caught in a snare.
+
+3. Human life, Koheleth declares, is unsatisfying. He inquired, he says,
+into everything that is done by men under the sun (i. 12-16): God has
+inflicted on men a restless desire for movement and work[2], yet life is
+but a catalogue of fruitless struggles. He gives a number of
+illustrations. In his character of king he tried all the bodily
+pleasures of life (ii. 1-11): he had houses, vineyards, gardens, parks,
+ponds, forests, servants, flocks and herds, treasures of gold and
+silver, singers, wives; all these he set himself to enjoy in a rational
+way--indeed, he found a certain pleasure in carrying out his designs,
+but, when all was done, he surveyed it only to see that it was weary and
+unprofitable. Dropping the role of Solomon and speaking as an observer
+of life, the author declares (iv. 4) that the struggle for success is
+the result of rivalry among men, which has no worthy outcome. The
+securing of riches is a fallacious achievement, for often wealth
+perishes by some accident (v. 13 f.), or its possessor is unable to
+enjoy it (vi. 1-3a), or he has no one to whom to leave it, and he cannot
+keep it--naked man comes into the world, naked he goes out. He does not
+consider the possibility of deriving enjoyment from wealth by helping
+the poor or encouraging learning (this latter, indeed, he looks on as
+vanity), and in general he recognizes no obligation on the part of a man
+to his fellows. A noteworthy survival of an old belief is found in vi.
+3: though a man have the great good fortune to live long and to have
+many children, yet, if he have not proper burial the blank darkness of
+an untimely birth is better than he: this latter is merely the negation
+of existence; the former, it appears to be held, is positive misfortune,
+the loss of a desirable place in Sheol, though elsewhere (ix. 5)
+existence in Sheol is represented as the negation of real life. It is
+not necessary to suppose that the writer has here any particular case in
+mind.
+
+If wealth be thus a vain thing, yet a sage might be supposed to find
+satisfaction in wisdom, that is, practical good sense and sagacity; but
+this also the author puts aside as bringing no lasting advantage, since
+a wise man must finally give up the fruit of his wisdom to someone else,
+who may be a fool, and in any case the final result for both fools and
+wise men is the same--both are forgotten (ii. 12-23). A particular
+instance is mentioned (ix. 13-15) of a beleaguered city saved by a wise
+man; but the man happened to be poor, and no one remembered him. The
+whole constitution of society, in fact, seems to the sage a lamentable
+thing: the poor are oppressed, the earth is full of their cries, and
+there is no helper (iv. 1); strange social upheavals may be seen: the
+poor[3] set in high places, the rich cast down, slaves on horseback,
+princes on foot (x. 5-7). He permits himself a sweeping generalization
+(vii. 25-28): human beings as a rule are bad: one may occasionally find
+a good man, never a good woman--woman is a snare and a curse. He (or an
+editor) adds (vii. 29) that this condition of things is due to social
+development: man was created upright (Gen. i. 27; Enoch lxix. 11), but
+in the course of history has introduced corrupting complications into
+life.
+
+4. The natural outcome of these experiences of the author is that he
+cannot recognize a moral government of the world. He finds, like Job,
+that there are good men who die prematurely notwithstanding their
+goodness, and bad men who live long notwithstanding their badness (vii.
+15), though long life, it is assumed, is one of the great blessings of
+man's lot; and in general there is no moral discrimination in the
+fortunes of men (viii. 14, ix. 2).
+
+5. There is no sacredness or dignity in man or in human life: man has no
+pre-eminence over beasts, seeing that he and they have the same final
+fate, die and pass into the dust, and no one knows what becomes of the
+spirit, whether in man's case it goes up to heaven, and in the case of
+beasts goes down into Sheol--death is practically the end-all; and so
+poor a thing is life that the dead are to be considered more fortunate
+than the living, and more to be envied than either class is he who never
+came into existence (iv. 2, 3). It is a special grievance that the
+wicked when they die are buried with pomp and ceremony, while men who
+have acted well are forgotten[4] in the city (viii. 10).
+
+6. That the author does not believe in a happy or active future life
+appears in the passage (iv. 2, 3) quoted above. The old Hebrew view of
+the future excluded from Sheol the common activities of life and also
+the worship of the national god (Isa. xxxviii. 18); he goes even beyond
+this in his conception of the blankness of existence in the underworld.
+The living, he says, at least know that they shall die, but the dead
+know nothing--the memory of them, their love, hate and envy, perishes,
+they have no reward, no part in earthly life (ix. 5, 6); there is
+absolutely no knowledge and no work in Sheol (ix. 10). His conclusion is
+that men should do now with all their might what they have to do; the
+future of man's vital part, the spirit, is wholly uncertain.
+
+7. His conception of God is in accord with these views. God for him is
+the creator and ruler of the world, but hardly more; he is the master of
+a vast machine that grinds out human destinies without sympathy with man
+and without visible regard for what man deems justice--a being to be
+acknowledged as lord, not one to be loved. There can thus be no social
+contact between man and God, no communion of soul, no enthusiasm of
+service. Moral conduct is to be regulated not by divine law (of this
+nothing is said) but by human experience. The author's theism is cold,
+spiritless, without influence on life.
+
+If now the question be asked what purpose or aim a man can have, seeing
+that there is nothing of permanent value in human work, an answer is
+given which recurs, like a refrain, from the beginning to the end of the
+book, and appears to be from the hand of the original author: after
+every description of the vanity of things comes the injunction to enjoy
+such pleasures as may fall to one's lot (ii. 24, 25, iii. 12, 13, 22, v.
+18, 19, viii. 15, ix. 7-10, xi. 7-xii. 7). Elsewhere (ii.), it is true,
+it is said that there is no lasting satisfaction in pleasure; but the
+sage may mean to point out that, though there is no permanent outcome to
+life, it is the part of common-sense to enjoy what one has. The
+opportunity and the power to enjoy are represented as being the gift of
+God; but this statement is not out of accord with the author's general
+position, which is distinctly theistic. All the passages just cited,
+except the last (xi. 7-xii. 7), are simple and plain, but the bearing of
+the last is obscured by interpolations. Obviously the purpose of the
+paragraph is to point out the wisdom of enjoying life in the time of
+youth while the physical powers are fresh and strong, and the impotency
+of old age has not yet crept in. Omitting xi. 8c, 9b, 10b, xii. 1a, the
+passage will read: "Life is pleasant in the bright sunshine--however
+long a man may live, he must be cheerful always, only remembering that
+dark days will come. Let the young man enjoy all the pleasures of youth,
+putting away everything painful, before the time comes when his bodily
+powers decay and he can enjoy nothing." To relieve the apparent
+Epicureanism of this passage, an editor has inserted reminders of the
+vanity of youthful pleasures, and admonitions to remember God and His
+judgment. The author, however, does not recommend dissipation, and does
+not mean to introduce a religious motive--he offers simply a counsel of
+prudence. The exhortation to remember the Creator in the days of youth,
+though it is to be retained in the margin as a pious editorial addition,
+here interrupts the line of thought. In xii. 1a some critics propose to
+substitute for "remember thy Creator" the expression of xi. 9, "let thy
+heart cheer thee"; but the repetition is improbable. Others would read:
+"remember thy cistern" (Bickell), or "thy well" (Haupt), that is, thy
+wife. The wife is so called in Prov. v. 15-19 in an elaborate poetical
+figure (the wife as a source of bodily pleasure), in which the reference
+is clear from the context; but there is no authority, in the Old
+Testament or in other literature of this period, for taking the term as
+a simple prose designation of a wife. Nor would this reference to the
+wife be appropriate in the connexion, since the writer's purpose is
+simply to urge men to enjoy life while they can. The paragraph (and the
+original book) concludes with a sustained and impressive figure, in
+which the failing body of the old man is compared to a house falling
+into decay: first, the bodily organs (xii. 3, 4a): the keepers of the
+house (the arms and hands) tremble, the strong men (the legs and perhaps
+the backbone) are bent, the grinding women (the teeth) cease to work,
+those that look out of the windows (the eyes) are darkened, the
+street-doors are shut, the sound of the mill being low (apparently a
+summary statement of the preceding details: communication with the outer
+world through the senses is cut off, the performance of bodily functions
+being feeble); the rest of v. 4 may refer to the old man's inability to
+make or hear music: in the house there is no sound of birds[5] or of
+singers, there are none of the artistic delights of a well-to-do
+household; further (v. 5a) the inmates of the house fear dangers from
+all powerful things and persons (the old man is afraid of everything),
+the almond tree blossoms (perhaps the hair turns white). The two next
+clauses are obscure.[6] Then comes the end: man goes to his everlasting
+home; the dust (the body) returns to the earth whence it came (Gen. ii.
+7), and the breath of life, breathed by God into the body, returns to
+him who gave it. This last clause does not affirm the immortality of the
+soul; it is simply an explanation of what becomes of the vital principle
+(the "breath of life" of Gen. ii. 7); its positive assertion is not in
+accord with the doubt expressed in iii. 21 ("who knows whether the
+spirit of man goes upward?"), and it seems to be from another hand than
+that of the author of the original book.
+
+There are other sayings in the book that appear to be at variance with
+its fundamental thought. Wisdom is praised in a number of passages (iv.
+13, vii. 5, 11, 12, 19, viii. 1, ix. 16, 17, x. 2, 3), though it is
+elsewhere denounced as worthless. It may be said that the author, while
+denying that wisdom (practical sagacity and level-headedness) can give
+permanent satisfaction, yet admits its practical value in the conduct of
+life. This may be so; but it would be strange if a writer who could say,
+"in much wisdom is much grief," should deliberately laud wisdom. The
+question is not of great importance and may be left undecided. It may be
+added that there are in the book a number of aphorisms about fools (v.
+3[4], vii. 5, 6, x. 1-3, 12-15) quite in the style of the book of
+Proverbs, some of them contrasting the wise man and the fool; these
+appear to be the insertions of an editor. Further, it may be concluded
+with reasonable certainty that the passages that affirm a moral
+government of the world are additions by pious editors who wished to
+bring the book into harmony with the orthodox thought of the time. Such
+assertions as those of ii. 26 (God gives joy to him who pleases him, and
+makes the sinner toil to lay up for the latter), viii. 12 (it shall be
+well with those that fear God, but not with the wicked), xii. 13 f.
+(man's duty is simply to obey the commands of God, for God will bring
+everything into judgment) are irreconcilable with the oft-repeated
+statement that there is no difference in the earthly lots of the
+righteous and the wicked, and no ethical life after death.
+
+Many practical admonitions and homely aphorisms are scattered through
+the book: iv. 5, quiet is a blessing; iv. 9-12, two are better than one;
+iv. 17 (Eng. v. 1), be reverent in visiting the house of God (the temple
+and the connected buildings)--to listen (to the service of song or the
+reading of Scripture) is better than to offer a foolish (thoughtless)
+sacrifice; v. 1 (2), be sparing of words in addressing God; v. 1-5
+(2-6), pay your vows--do not say to the priest's messenger that you made
+a mistake; vii. 2-4, sorrow is better than mirth; vii. 16-18, be not
+over-righteous (over-attentive to details of ritual and convention) or
+over-wicked (flagrantly neglectful of established beliefs and customs);
+here "righteous" and "wicked" appear to be technical terms designating
+two parties in the Jewish world of the 2nd and 1st centuries B.C., the
+observers and the non-observers of the Jewish ritual law; these parties
+represent in a general way the Pharisees and the Sadducees; viii. 2-4,
+x. 20, it is well to obey kings and to be cautious in speaking about
+them, for there are talebearers everywhere; vii. 20, no man is free from
+sin; vii. 21, do not listen to all that you may overhear, lest you hear
+yourself ill spoken of; ix. 4, a living dog is better than a dead lion;
+xi. 1-6, show prudence and decision in business; do not set all your
+goods on one venture; act promptly and hope for the best. At the close
+of the book (xii. 9-12) there are two observations that appear to be
+editorial recommendations and cautions. First, Koheleth is endorsed as
+an industrious, discriminating and instructive writer. Possibly this is
+in reply to objections that had been made to what he had written. There
+follows an obscure passage (v. 11) which seems to be meant as a
+commendation of the teaching of the sages in general: their words are
+said to be like goads (inciting to action) and like nails driven in a
+building (giving firmness to character); they issue from masters of
+assemblies,[7] heads of academies (but not of the Sanhedrin). The
+succeeding clause "they are given from one shepherd" may refer to a
+collection or revision by one authoritative person, but its relevancy is
+not obvious. The "shepherd" cannot be God (Gen. xlix. 24; Ps. xxiii. 1);
+the poetical use of the word would not be appropriate here. The clause
+is possibly a gloss, a comment on the preceding expression. A caution
+against certain books is added (v. 12), probably works then considered
+harmful (perhaps philosophic treatises), of which, however, nothing
+further is known.
+
+_Composition of the Book._--If the analysis given above is correct, the
+book is not a unit; it contains passages mutually contradictory and not
+harmonizable. Various attempts have been made to establish its unity.
+The hypothesis of "two voices" is now generally abandoned; there is no
+indication of a debate, of affirmations and responses. A more plausible
+theory is that the author is an honest thinker, a keen observer and
+critic of life, who sees that the world is full of miseries and unsolved
+problems, regards as futile the attempts of his time to demonstrate an
+ethically active future life, and, recognizing a divine author of all,
+holds that the only wise course for men is to abandon the attempt to get
+full satisfaction out of the struggle for pleasure, riches and wisdom,
+and to content themselves with making the best of what they have. This
+conception of him is largely true, as is pointed out above, but it does
+not harmonize the contradictions of the book, the discrepancies between
+the piety of some passages and the emotional indifference toward God
+shown in others. Other of the Biblical Wisdom books (Job, Proverbs) are
+compilations--why not this? It is not necessary to multiply authors, as
+is done, for example, by Siegfried, who supposes four principal writers
+(a pessimistic philosopher, an Epicurean glossator, a sage who upholds
+the value of wisdom, and an orthodox editor) besides a number of
+annotators; it is sufficient to assume that several conservative scribes
+have made short additions to the original work. Nor is it worth while to
+attempt a logical or symmetrical arrangement of the material. It has
+been surmised (by Bickell) that the sheets of the original codex became
+disarranged and were rearranged incorrectly;[8] by other critics
+portions of the book are transferred hither and thither; in all cases
+the critic is guided in these changes by what he conceives to have been
+the original form of the book. But it is more probable that we have it
+in the form in which it grew up--a series of observations by the
+original author with interspersed editorial remarks; and it is better to
+preserve the existing form as giving a record of the process of growth.
+
+_Date._--As to the date of the book, though there are still differences
+of opinion among scholars, there is a gradual approach to a consensus.
+The Solomonic authorship has long since been given up: the historical
+setting of the work and its atmosphere--the silent assumption of
+monotheism and monogamy, the non-national tone, the attitude towards
+kings and people, the picture of a complicated social life, the strain
+of philosophic reflection--are wholly at variance with what is known of
+the 10th century B.C. and with the Hebrew literature down to the 5th or
+4th century B.C. The introduction of Solomon, the ideal of wisdom, is a
+literary device of the later time, and probably deceived nobody. The
+decisive considerations for the determination of the date are the
+language, the historical background and the thought. The language
+belongs to the post-classical period of Hebrew. The numerous Aramaisms
+point to a time certainly not earlier than the 4th century B.C., and
+probably (though the history of the penetration of Aramaic into Hebrew
+speech is not definitely known) not earlier than the 3rd century. More
+than this, there are many resemblances between the dialect of Koheleth
+and that of Mishna. Not only are new words employed, and old words in
+new significations, but the grammatical structure has a modern
+stamp--some phrases have the appearance of having been translated out of
+Aramaic into Hebrew. By about the beginning of our era the Jews had
+given up Hebrew and wrote in Aramaic; the process of expulsion had been
+going on, doubtless, for some time; but comparison with the later extant
+literature (_Chronicles_, the Hebrew _Ecclesiasticus_ or _Ben-Sira_,
+_Esther_) makes it improbable that such Hebrew as that of Koheleth would
+have been written earlier than the 2nd century B.C. (for details see
+Driver's _Introduction_). The general historical situation, also,
+presupposed or referred to, is that of the period from the year 200 B.C.
+to the beginning of our era; in particular, the familiar references to
+kings as a part of the social system, and to social dislocations
+(servants and princes changing places, x. 7), suggest the troublous time
+of the later Greek and the Maccabean rulers, of which the history of
+Josephus gives a good picture.
+
+The conception of the world and of human life as controlled by natural
+law, a naturalistic cosmos, is alien not only to the prophetic and
+liturgical Hebrew literature but also to Hebrew thought in general.
+Whether borrowed or not, it must be late; and its resemblance to Greek
+ideas suggests Greek influence. The supposition of such influence is
+favoured by some critics (Tyler, Plumptre, Palm, Siegfried, Cheyne in
+his _Jewish Religious Life after the Exile_, and others), rejected by
+some (Zeller, Renan, Kleinert and others). This disagreement comes
+largely from the attempts made to find definitely expressed Greek
+philosophical dogmas in the book; such formulas it has not, but the
+general air of Greek reflection seems unmistakable. The scepticism of
+Koheleth differs from that of Job in quality and scope: it is deliberate
+and calm, not wrung out by personal suffering; and it relates to the
+whole course and constitution of nature, not merely to the injustices of
+fortune. Such a conception has a Greek tinge, and would be found in
+Jewish circles, probably, not before the 2nd century B.C.
+
+A precise indication of date has been sought in certain supposed
+references or allusions to historical facts. The mention of persons who
+do not sacrifice or take oaths (ix. 2) is held by some to point to the
+Essenes; if this be so, it is not chronologically precise, since we have
+not the means of determining the beginning of the movement of thought
+that issued in Essenism. So also the coincidences of thought with
+_Ben-Sira_ (_Ecclesiasticus_) are not decisive: cf. iii. 14 with _B.S._
+xviii. 6; v. 2-6 (3-7) with _B.S._ xxxiv. 1-7; vii. 19 with _B.S._
+xxxvii. 14; x. 8 with _B.S._ xxvii. 26a; xi. 10 with _B.S._ xxx. 21;
+xii. 10, 11 with _B.S._ xxxix. 2 ff., xii. 13 with _B.S._ xliii. 27; if
+there be borrowing in these passages, it is not clear on which side it
+lies; and it is not certain that there is borrowing--the thoughts may
+have been taken independently by the two authors from the same source.
+In any case, since _Ben-Sira_ belongs to about 180 B.C., the date of
+Koheleth, so far as these coincidences indicate it, would not be far
+from 200 B.C. The contrast made in x. 16 f. between a king who is a boy
+and one who is of noble birth may allude to historical persons. The
+antithesis is not exact; we expect either "boy and mature man" or
+"low-born and high-born." The "child" might be Antiochus V. (164 B.C.),
+or Ptolemy V., Epiphanes (204 B.C.), but the reference is too general to
+be decisive. The text of the obscure passage iv. 13-16 is in bad
+condition, and it is only by considerable changes that a clear meaning
+can be got from it. The two personages--the "old and foolish king" and
+the "poor and wise youth"--have been supposed (by Winckler) to be
+Antiochus Epiphanes (175-164 B.C.) and Demetrius (162-150 B.C.), or (by
+Haupt) Antiochus and the impostor Alexander Balas (150-146 B.C.), or (by
+others) Demetrius and Alexander; in favour of Alexander as the "youth"
+it may be said that he was of obscure origin, was at first popular, and
+was later abandoned by his friends. Such identifications, however, do
+not fix the date of the book precisely; the author may have referred to
+events that happened before his time. The reign of Herod, a period of
+despotism and terror, and of strife between Jewish religious parties, is
+preferred by some scholars (Graetz, Cheyne and others) as best answering
+to the social situation depicted in the book, while still others (as
+Renan) decide for the reign of Alexander Jannaeus (104-78 B.C.). The
+data are not numerous and distinct enough to settle the question beyond
+determining general limits: for reasons given above the book can hardly
+have been composed before about 200 B.C., and if, as is probable, a
+Septuagint translation of it was made (though the present Septuagint
+text shows the influence of Aquila), it is to be put earlier than 50
+B.C. Probably also, its different parts are of different dates.
+
+Of the author nothing is known beyond the obvious fact that he was a man
+of wide observation and philosophic thought, of the Sadducean type in
+religion, but non-Jewish in his attitude toward life. He was, doubtless,
+a man of high standing, but neither a king nor a high-priest, certainly
+not the apostate priest Alcimus (1 Macc. vii. ix.); nor was he
+necessarily a physician--there are no details in ch. xii. or elsewhere
+that any man of good intelligence might not know. The book is written in
+prose, some of which is rhythmical, with bits of verse here and there:
+thus i. 2-11 is balanced prose, 12-14 plain prose, 15 a couplet, i.
+16-ii. 25 simple prose, vii. contains a number of poetical aphorisms,
+and so on. Some of the verses are apparently from the author, some from
+editors.
+
+The fortunes of the book are not known in detail, but it is clear that
+its merciless criticism of life and its literary charm made it popular,
+while its scepticism excited the apprehensions of pious conservatives.
+Possibly the _Wisdom of Solomon_ (c. 50 B.C.) was written partly as a
+reply to it. The claim of sacredness made for it was warmly contested by
+some Jewish scholars. In spite of the relief afforded by orthodox
+additions, it was urged that its Epicurean sentiments contradicted the
+Torah and favoured heresy. Finally, by some process of reasoning not
+fully recorded, the difficulties were set aside and the book was
+received into the sacred canon; Jerome (on Eccl. xii. 13, 14) declares
+that the decisive fact was the orthodox statement at the end of the
+book: the one important thing is to fear God and keep His commandments.
+The probability is that the book had received the stamp of popular
+approbation before the end of the 1st century of our era, and the
+leading men did not dare to reject it. It is not certain that it is
+quoted in the New Testament, but it appears to be included in Josephus'
+list of sacred books.
+
+  LITERATURE.--For the older works see Zoeckler (in Lange's _Comm._); for
+  Jewish commentaries see Zedner, _Cat. of Heb. books in Libry. of Brit.
+  Mus._ (1867), and for the history of the interpretations, C.D.
+  Ginsburg, _Coheleth_ (1861). _Introductions_ of A. Kuenen, S.R.
+  Driver, Cornhill, Koenig. Articles in Herzog-Hauck, _Realencykl._ (by
+  P. Kleinert); Hastings, _Dict. Bible_ (by A.S. Peake); T.K. Cheyne,
+  _Encycl. Bibl._ (by A.B. Davidson); _Jew. Encycl._ (by D.S.
+  Margoliouth). Commentaries: F. Hitzig (1847); C.D. Ginsburg (1861); H.
+  Graetz (1871); Tyler (1874); Delitzsch (1875); E.H. Plumptre (1881);
+  C.H.H. Wright (1883); Nowack, revision of Hitzig (1883); Volck (in
+  Strack u. Zoeckler's _Kurzgef. Komm._, 1889); Wildeboer (in Marti's
+  _Kurzer Hand-Comm._, 1898); C. Siegfried (in W. Nowack's _Handkomm._,
+  1898); Oort (in _De Oude Test._, 1899). Other works: C. Taylor, _Dirge
+  of Koh._ (1874); Wuensche, _Midrash_ on Koh. (in his _Biblioth.
+  rabbin._, 1880); E. Renan, _L'Ecclesiaste_ (1882); Bickell, _Der
+  Prediger_ (1884) and _Kohel.-Untersuchungen_ (1886; Engl. by E.J.
+  Dillon, _Sceptics of Old Test._, 1895); Schiffer, _Das Buch Koh. nach
+  d. Auffass. d. Weisen d. Talmuds_, &c. (1884); A. Palm, _Qoh. u. d.
+  nach-aristotel. Philosophie_ (1885) and _Die Qoh.-Lit._ (1886); E.
+  Pfleiderer, _Die Phil. d. Heraklit_, &c. (1886); Cheyne, _Job and
+  Solomon_ (1887) and _Jew. Relig. Life_, &c. (1898); W. Euringer, _Der
+  Masorahtext d. Koh._ (1890); W.T. Davison, _Wisdom-Lit. of Old Test._
+  (1894); H. Winckler, in his _Altorient. Forschungen_ (1898); J.F.
+  Genung, _Words of Koh._ (Boston, Mass., 1904); P. Haupt,
+  _Ecclesiastes_ (Baltimore, 1905). The rabbinical discussions of the
+  book are mentioned in _Shabbath_, 30b; _Megilla_, 7a; _Eduyoth_, v. 3;
+  _Mishna Yadaim_, iii. 5, iv. 6; _Midrash Koheleth_ (on xi. 9), _Aboth
+  d' Rab. Nathan_, i.     (C. H. T.*)
+
+
+FOOTNOTES:
+
+  [1] The Hebrew has the definite article, "the whole," [Greek: to
+    pan].
+
+  [2] In fact, he suggests, a curse, as in Gen. iii. 17-19, though with
+    a wider sweep than that passage has in mind.
+
+  [3] The text has "folly," but the parallelism and v. 7 point to
+    social, not intellectual, conditions, and a slight change ([Hebrew:
+    haskel] for [Hebrew: misken]) gives the sense "poor."
+
+  [4] The Septuagint has less well: "They (the wicked) are praised in
+    the city."
+
+  [5] The clause is obscure; literally "he (or, one) rises at (?) the
+    voice of the bird," usually understood to refer to the old man's
+    inability to sleep in the morning; but this is not a universal trait
+    of old age, and besides, a reference to affairs in the house is to be
+    expected; the Hebrew construction also is of doubtful correctness. A
+    change of the Hebrew text seems necessary; possibly we should read
+    [Hebrew: ishpal kol], "low is the voice," instead of [Hebrew: yakum
+    lekol] "he rises up at the voice."
+
+  [6] The second is perhaps to be read: "the caper-berry blooms" (white
+    hair); usually "the caper-berry loses its appetizing power"; Eng.
+    Auth. Vers. "desire shall fail." For the meaning of the word _abyona_
+    ("caper-berry," not "desire" or "poverty"), see art. by G.F. Moore in
+    _Journ. of Bibl. Lit._ x. 1 (Boston, Mass., 1891).
+
+  [7] This is the Talmudic understanding of the Hebrew expression
+    (Jerus. Sanhed. 10, 28a, cf. Sanhed. 12a; see Ecclus. xxxix. 2).
+    There is no good authority for the renderings "collectors of maxims,"
+    "collections of maxims."
+
+  [8] It is not certain that the codex form was in use in Palestine or
+    in Egypt as early as the 2nd or the 1st century B.C.
+
+
+
+
+ECCLESIASTICAL COMMISSIONERS, in England, a body corporate, whose full
+title is "Ecclesiastical and Church Estates Commissioners for England,"
+invested with very important powers, under the operation of which
+extensive changes have been made in the distribution of the revenues of
+the Established Church. Their appointment was one of the results of the
+vigorous movements for the reform of public institutions which followed
+the Reform Act of 1832. In 1835 two commissions were appointed "to
+consider the state of the several dioceses of England and Wales, with
+reference to the amount of their revenues and the more equal
+distribution of episcopal duties, and the prevention of the necessity of
+attaching by commendam to bishoprics certain benefices with cure of
+souls; and to consider also the state of the several cathedral and
+collegiate churches in England and Wales, with a view to the suggestion
+of such measures as might render them conducive to the efficiency of the
+established church, and to provide for the best mode of providing for
+the cure of souls, with special reference to the residence of the clergy
+on their respective benefices." And it was enacted by an act of 1835
+that during the existence of the commission the profits of dignities and
+benefices without cure of souls becoming vacant should be paid over to
+the treasurer of Queen Anne's Bounty. In consequence of the
+recommendation of these commissioners, a permanent commission was
+appointed by the Ecclesiastical Commissioners Act 1836 for the purpose
+of preparing and laying before the king in council such schemes as
+should appear to them to be best adapted for carrying into effect the
+alterations suggested in the report of the original commission and
+recited in the act. The new commission was constituted a corporation
+with power to purchase and hold lands for the purposes of the act,
+notwithstanding the statutes of mortmain. The first members of the
+commission were the two archbishops and three bishops, the lord
+chancellor and the principal officers of state, and three laymen named
+in the act.
+
+The constitution of the commission was amended by the Ecclesiastical
+Commissioners Act 1840 and subsequent acts, and now consists of the two
+archbishops, all the bishops, the deans of Canterbury, St Paul's and
+Westminster, the lord chancellor, the lord president of the council, the
+first lord of the treasury, the chancellor of the exchequer, the home
+secretary, the lord chief justice, the master of the rolls, two judges
+of the admiralty division, and certain laymen appointed by the crown and
+by the archbishop of Canterbury. The lay commissioners are required to
+be "members of the Church of England, and to subscribe a declaration to
+that effect." The crown also appoints two laymen as church estates
+commissioners, and the archbishop of Canterbury one. These three are the
+joint treasurers of the commission, and constitute, along with two
+members appointed by the commission, the church estates committee,
+charged with all business relating to the sale, purchase, exchange,
+letting or management of any lands, tithes or hereditaments. The
+commission has power to make inquiries and examine witnesses on oath.
+Five commissioners are a quorum for the transaction of business,
+provided two of them are church estates commissioners; two
+ecclesiastical commissioners at least must be present at any proceeding
+under the common seal, and if only two are present they can demand its
+postponement to a subsequent meeting. The schemes of the commission
+having, after due notice to persons affected thereby, been laid before
+the king in council, may be ratified by orders, specifying the times
+when they shall take effect, and such orders when published in the
+_London Gazette_ have the same force and effect as acts of parliament.
+
+  The recommendations of the commission recited in the act of 1836 are
+  too numerous to be given here. They include an extensive rearrangement
+  of the dioceses, equalization of episcopal income, providing
+  residences, &c. By the act of 1840 the fourth report of the original
+  commissioners, dealing chiefly with cathedral and collegiate churches,
+  was carried into effect, a large number of canonries being suspended,
+  and sinecure benefices and dignities suppressed.
+
+  The emoluments of these suppressed or suspended offices, and the
+  surplus income of the episcopal sees, constitute the fund at the
+  disposal of the commissioners. By an act of 1860, on the avoidance of
+  any bishopric or archbishopric, all the land and emoluments of the
+  see, except the patronage and lands attached to houses of residence,
+  become, by order in council, vested in the commissioners, who may,
+  however, reassign to the see so much of the land as may be sufficient
+  to secure the net annual income named for it by statute or order. All
+  the profits and emoluments of the suspended canonries, &c., pass over
+  to the commissioners, as well as the separate estates of those
+  deaneries and canonries which are not suspended. Out of this fund the
+  expenses of the commission are to be paid, and the residue is to be
+  devoted to increasing the efficiency of the church by the augmentation
+  of the smaller bishoprics and of poor livings, the endowment of new
+  churches, and employment of additional ministers.
+
+  The substitution of one central corporation for the many local and
+  independent corporations of the church, so far at least as the
+  management of property is concerned, was a constitutional change of
+  great importance, and the effect of it undoubtedly was to correct the
+  anomalous distribution of ecclesiastical revenues by equalizing
+  incomes and abolishing sinecures. At the same time it was regarded as
+  having made a serious breach in the legal theory of ecclesiastical
+  property. "The important principle," says Cripps, "on which the
+  inviolability of the church establishment depends, that the church
+  generally possesses no property as a corporation, or which is
+  applicable to general purposes, but that such particular
+  ecclesiastical corporation, whether aggregate or sole, has its
+  property separate, distinct and inalienable, according to the
+  intention of the original endowment, was given up without an effort to
+  defend it" (_Law Relating to the Church and Clergy_, p. 46).
+
+
+
+
+ECCLESIASTICAL JURISDICTION. This phrase in its primary sense imports
+not jurisdiction over ecclesiastics, but jurisdiction exercised by
+ecclesiastics over other ecclesiastics and over the laity.
+"Jurisdiction" is a word borrowed from the jurists which has acquired a
+wide extension in theology, wherein, for example, it is frequently used
+in contradistinction to "order," to express the right to administer
+sacraments as something superadded to the _power_ to celebrate them. So
+it is used to express the territorial or other limits of ecclesiastical,
+executive or legislative authority. Here it is used, in the limited
+sense defined by an American Court, as "the authority by which judicial
+officers take cognizance of and decide causes."
+
+
+  Origin of ecclesiastical jurisdiction.
+
+Such authority in the minds of lay Roman lawyers who first used this
+word "jurisdiction" was essentially temporal in its origin and in its
+sphere. The Christian Church transferred the notion to the spiritual
+domain as part of the general idea of a Kingdom of God correlative, on
+the spiritual side of man upon earth, to the powers, also ordained of
+God, who had dominion over his temporal estate (see CANON LAW). As the
+Church in the earliest ages had executive and legislative power in its
+own spiritual sphere, so also it had "judicial officers," "taking
+cognizance of and deciding causes." Only before its union with the
+State, its power in this direction, as in others, was merely over the
+spirits of men. Coercive temporal authority over their bodies or estates
+could only be given by concession from the temporal prince. Moreover,
+even spiritual authority over members of the Church, i.e. baptized
+persons, could not be exclusively claimed as _of right_ by the Church
+tribunals, if the subject matter of the cause were purely temporal. On
+the other hand, it is clear that _all_ the faithful were subject to
+these courts (when acting within their own sphere), and that, in the
+earliest times, no distinction was made in this respect between clergy
+and laity.
+
+The fundamental principle of ecclesiastical jurisdiction with its
+"sanction" of excommunication will be found in Christ's words in Matt.
+xviii. 15-18. A very early example of criminal spiritual jurisdiction
+exercised by St Paul is found in the case of the incestuous Corinthian
+(1 Cor. v.). We find later the same apostle exercising like jurisdiction
+in the cause of Hymenaeus and Alexander (1 Tim. i. 20). After the time
+of the Apostles, we find this criminal jurisdiction exercised by the
+bishops individually over their respective "subjects"--doubtless with
+the advice of their presbyters according to the precept of St Ignatius
+(c. 110). As neighbouring dioceses coalesced into "provinces" and
+provinces into larger districts (corresponding to the civil "dioceses"
+of the later Roman Empire), the provincial synods of bishops and the
+synods of the larger districts acquired a criminal jurisdiction, still
+purely spiritual, of their own. At first this was "original" and mainly
+(although not exclusively) over bishops (of the province or larger
+district). The beginnings of an appellate jurisdiction in the cases of
+clerics and laymen may be traced before the conversion of the Empire.
+The bishop over whom the synod of neighbouring bishops had exercised
+jurisdiction had no formal right of appeal; but sometimes bishops in
+other parts of the Church would refuse to acknowledge the local
+synodical sentence and would communicate with a bishop whom they deemed
+unjustly deposed. The theory, as expressed in legal phrase by St Cyprian
+in the 3rd century, was that the apostolic power of delegated
+sovereignty from the Lord, alike legislative and judicial, was held in
+joint-tenancy by the whole body of Catholic bishops. In both capacities,
+however, a certain undefined pre-eminence was conceded to the occupants
+of "Apostolic" sees, i.e. sees traditionally founded by Apostles, or of
+sees with a special secular position.
+
+Even before the edict of Milan, at least as early as the latter half of
+the 3rd century, the spiritual sentences of deposition from office had
+sometimes indirect temporal consequences recognized by the secular
+courts. The classical example is the case of Paul of Samosata, bishop of
+Antioch. It would seem that, in the intervals of persecution, some
+rights of property were recognized in the Christian Church and its
+officers; although the Church was an illegal society. After some
+previous abortive trials, Paul of Samosata was deposed and
+excommunicated, in 269, by a great synod of the Antiochene district.
+Paul, notwithstanding his deposition, kept possession of the episcopal
+residence. The local church sought recovery of it before the tribunals
+of the Empire. The judicial authorities requested a rescript from the
+emperor Aurelian for the decision of the cause. Aurelian referred the
+matter to the bishop of Rome and the bishops of Italy, who gave their
+award in favour of the Antiochene Church.
+
+
+  Temporal Jurisdiction of the Church.
+
+Side by side with this which we may call criminal jurisdiction--none the
+less real or coercive because its sanctions were purely spiritual--there
+grew up a quasi-jurisdiction in causes entirely temporal, based upon the
+free consent of the parties to accept the arbitration of the bishop.
+This system had also its roots in the New Testament (see Matt, xviii.
+15-17 and 1 Cor. vi. 1-8). In the matter of criminal jurisdiction we
+paused for a moment at the edict of Milan; but we may at once trace this
+second or civil branch of episcopal judicature or quasi-judicature down
+as far as the reign of Charlemagne, when it underwent a fundamental
+change, and became, if _either_ litigant once chose, no longer a matter
+of consent but of right.
+
+Constantine decreed that judgment in causes might be passed by bishops
+when litigants preferred their adjudication to that of the secular
+courts (see his epistle to the Numidian bishops and _Cod. Theodos. Tit.
+de Episcopis_). The episcopal judgment was to be equivalent to that of
+the emperor and irreversible, and the civil authorities were to see to
+its execution. Saints Ambrose and Augustine both spent days in deciding
+temporal causes. Honorius, in the West, at the end of the 4th century,
+made a constitution providing that if any desired to litigate before the
+bishops they should not be forbidden, but that in civil matters the
+prelates should render judgment in the manner of arbitrators by consent
+(_Cod._ 1, _Tit._ iv.). Where the faithful had had recourse to the
+bishop, no appeal was to be allowed, and the judges were to command
+execution of the episcopal decree. A quarter of a century later,
+however, Valentinian III. in the West expressly provided that bishops
+were not to be permitted to be judges (that is, of course, in temporal
+causes), save by the consent of the parties. This legislation was,
+substantially, adopted by Justinian.
+
+On the revival of the Western Empire, however, Charlemagne, in the
+beginning of the 9th century, under the mistaken belief that he was
+following the authority of Constantine I. and Theodosius I., took a
+great step forward, by which the bishop ceased to be a mere legally
+indicated arbitrator by consent in secular causes, and became a real
+judge. By a capitulary he provided that either litigant, without the
+consent of the other party, and not only at the beginning of a suit but
+at any time during its continuance, might take the cause from lay
+cognizance and transfer it to the bishop's tribunal. He re-enacted the
+prohibition of appeal.
+
+It should be remembered that, from the latter part of the 3rd century,
+the leading bishops had generally been trained in secular learning. St
+Cyprian, St Ambrose and St Augustine, St Paulinus of Nola and St John
+Chrysostom had practised law as teachers or advocates. St Ambrose and St
+Paulinus had even held high administrative and judicial offices.
+
+
+  Roman empire from Constantine.
+
+To return to the evolution of ecclesiastical jurisdiction from the time
+of Constantine. With the "Nicene period" came a great development on the
+criminal side. A system begins to be formed, and the secular arm
+supports the decrees of the Church. The first trace of system is in the
+limited right of appeal given by the first oecumenical council of Nicaea
+and its provision that episcopal sentences or those of provincial synods
+on appeal were to be recognized throughout the world. The fifth canon
+provides that those, whether clerics or laymen, who are cut off from
+communion in any particular province are not to be admitted thereto
+elsewhere. Still examination must be had whether persons have been
+expelled from the congregation by any episcopal small-mindedness
+([Greek: mikropsychia]), or contentious spirit, or such-like harshness
+([Greek: aedia]). That this may be conveniently inquired into, synods
+are to be held, three in every year, in each province, and questions of
+this kind examined. There is to be no "stay of execution"; the episcopal
+sentence is to prevail until the provincial synod otherwise decide. It
+will be noticed that as yet no provision is made for appeals by
+_bishops_ from provincial synods sitting in first instance.
+
+The edicts of Milan had only admitted the Christian Church among the
+number of lawful religions; but the tendency (except in the time of
+Julian) was towards making it the only lawful religion. Hence the
+practice, immediately after Nicaea I., of superadding banishment by the
+emperor to synodical condemnation. The dogmatic decrees of Nicaea I.
+were at once enforced in this temporal manner. On the other hand, the
+Arian reaction at court worked its objects (see Pusey, _Councils of the
+Church_) by using the criminal spiritual jurisdiction of synods against
+the Catholics--often packing the synods for the purpose. The acts of
+councils of this age are full of the trials of bishops not only for
+heresy but for immorality and common law crimes. The accusations are
+frequently unfounded; but the trials are already conducted in a certain
+regular forensic form. The secular authorities follow the precedent of
+Nicaea I. and intervene to supplement the spiritual sentence by
+administrative penalties. Sometimes an imperial officer of high rank
+(as, e.g. a "count") is present at the synod, as an assessor to maintain
+order and advise upon points of procedure. Leading examples may be found
+in the various prosecutions of St Athanasius, in whose case also there
+is the germ of an appeal, _tanquam ab abusu_. It has been contended
+that, according to later and more formulated jurisprudence, such an
+appeal would have lain, since the trial at Tyre was not concerned with
+purely spiritual matters (see the case in Hefele, _Councils_, in loc.).
+
+The trial of St Athanasius led to extensions of the right of appeal.
+This was favoured by the development of the greater sees into positions
+of great administrative dignity, shortly to be called "patriarchal." A
+synod was held at Rome, attended by bishops from various regions, which
+reversed the original judgment of the synod of Tyre which had condemned
+Athanasius. A much larger synod at Antioch, gathered only from the East,
+on the other hand, confirmed that judgment. This last synod did
+something to systematize the criminal procedure of the Church, and its
+legislation has been always received.
+
+This legislation marks another step forward. Deposition of a bishop by a
+synod, or of a priest or deacon by his bishop, is to take effect even
+pending an appeal, and a cleric continuing his functions after sentence
+in first instance is to lose all right of appeal. The appeal given by
+Nicaea I. to clerics and laymen from episcopal excommunications is
+extended. The synod may restore them if convinced of the justice of
+their cause (and not merely in cases of [Greek: aedia]). A bishop may
+appeal to a great assembly of bishops. Any bishop, priest or deacon
+"importuning" the emperor, instead of exerting his right of appeal to
+synods, is to lose all right of appeal and never to be restored or
+pardoned. If a provincial synod be divided as to the guilt of a bishop,
+the metropolitan is to convene bishops from the neighbouring provinces
+to decide the cause jointly with the bishops of the original province.
+
+A few years later, in 347, the council of Sardica, a council of
+practically the whole West save Africa, reversed Tyre and acquitted St
+Athanasius after a full judicial inquiry. This council endeavoured to
+set up a system of appeals in the case of bishops, in which the see of
+Rome was made to play a great part. "Out of honour to the memory of St
+Peter," a condemned bishop may ask the intervention of Rome. If this be
+done, the synod of first instance is to send letters to Julius, bishop
+of Rome. If that prelate think the cause should be heard again, he is to
+appoint judges; if otherwise, the original judgment is to be confirmed.
+Pending appeal, the appellant's see is not to be filled up. The judges
+appointed by the bishop of Rome to hear the appeal are to be from the
+neighbouring provinces. The appellant may, however, request that bishop
+to send priests from his side to sit with the synod of appeal. If such
+priests are sent, they are to preside in the court of appeal. These
+canons were always repudiated in the East, and when, sixty years
+afterwards, they were, for the first time, heard of in Africa, they were
+repudiated there also.
+
+A rescript of Gratian in 378 empowered the bishop of Rome to judge
+bishops with the assistance of six or seven other bishops or, in the
+case of a metropolitan, of fifteen comprovincial bishops. A bishop
+refusing to come to Rome was to be brought there by the civil power. The
+rescript, however, was not incorporated in the Codes and perhaps was
+only a temporary measure.
+
+The tendency to give pre-eminence to Rome appears again in an imperial
+letter to St Flavian, who, in the judgment of the East, was bishop of
+Antioch, but who was rejected by the West and Egypt, summoning him to
+Rome to be there judged by the bishops of the imperial city--a summons
+which St Flavian did not obey (Tillemont, _Mem. Ecc._). In Africa in the
+beginning of the 5th century Apiarius, a priest who had been deposed by
+the bishop of Sicca for immorality, and whose deposition had been
+affirmed by the "provincial synod," instead of further appealing to a
+general synod of Africa, carried his appeal to Pope Zosimus. The pope
+received the appeal, absolved him and restored him to the rank of
+priest, and sent a bishop and two priests as legates to Africa with
+instructions to them to hear the cause of Apiarius anew and for
+execution of their sentence to crave the prefect's aid; moreover, they
+were to summon the bishop of Sicca to Rome and to excommunicate him,
+unless he should amend those things which the legates deemed wrong. The
+upshot of a long conflict was that the papal claim to entertain appeals
+from Africa by priests and deacons was rejected by the African bishops,
+who in their final synodical epistle also repudiate in terms any right
+of appeal by African _bishops_ to "parts beyond the seas" (see Hefele,
+_Councils_, bk. viii.).
+
+The story of the administrative development of the Church in the 5th
+century is mainly the story of the final emergence and constitution of
+the great "patriarchates," as authorities superior to metropolitans and
+provincial synods. In consequence of the occupants of the thrones of
+Constantinople and Alexandria falling successively into opposite
+heresies, the question arose how "patriarchs" were to be judged. In both
+cases, as it seems, an attempt was made by the bishop of Rome to depose
+the erring patriarch by his authority as primate of Christendom, acting
+in concert with a Western synod. In both cases, apparently, an
+oecumenical synod ignored the Roman deposition and judged the alleged
+offences of the respective patriarchs in first and last instance. The
+third and fourth oecumenical synods (Ephesus, 431; Chalcedon, 451) were
+primarily tribunals for the trials of Nestorius and Dioscorus; it was
+secondarily that they became organs of the universal episcopate for the
+definition of the faith, or legislative assemblies for the enactment of
+canons. Nothing is more remarkable than their minute care as to
+observance of rules of procedure. In both cases, imperial assessors were
+appointed. At Ephesus the Count Candidian was commissioned to maintain
+order, but took little part in the proceedings. At Chalcedon, on the
+other hand, the imperial commissioners decided points of order, kept the
+synod to the question, took the votes and adjourned the court. But the
+synod alone judged and pronounced sentence. No oecumenical synod has
+tried a patriarch of Old Rome while yet in the flesh. The fifth
+oecumenical council came nearest to so doing, in the case of Vigilius.
+That pope, although in Constantinople, refused to attend the sittings of
+the council. He was cited three times, in the canonical manner, and upon
+not appearing was threatened in the third session with anathema (Hefele,
+_Councils_, sect. 268 _ad fin._). He was not, however, charged with
+direct heresy, as were Nestorius and Dioscorus, and the synod seems to
+have hesitated to deal stringently with the primate of Christendom. In
+the seventh session it accepted the suggestion of Justinian, merely to
+order the name of Vigilius to be removed from the liturgical prayers, at
+the same time expressing its desire to maintain unity with the see of
+Old Rome (Hefele, sect. 273). After the council, Justinian banished the
+pope to Egypt, and afterwards to an island, until he accepted the
+council, which he ultimately did (ib. 276). The sixth oecumenical synod
+decreed that the dead pope Honorius should be "cast out from the holy
+Catholic Church of God" and anathematized, a sentence approved by the
+reigning pope Leo II. and affirmed by the seventh oecumenical synod in
+787.
+
+The constitution of the patriarchal system resulted in the recognition
+of a certain right of appeal to Rome from the larger part of the West.
+Britain remained outside that jurisdiction, the Celtic churches of the
+British islands, after those islands were abandoned by the Empire,
+pursuing a course of their own. In the East, Constantinople, from its
+principality, acquired special administrative pre-eminence, naturally
+followed, as in the case of "old Rome," by judicial pre-eminence. An
+example of this is found in the ninth canon of Chalcedon, which also
+illustrates the enforcement upon a clerical plaintiff in dispute with a
+brother cleric of that recourse to the arbitration of their
+ecclesiastical superior already mentioned. The canon provides that any
+clerk having a complaint against another clerk must not pass by his own
+bishop and turn to secular tribunals, but first lay bare his cause
+before him, so that by the sentence of the bishop himself the dispute
+may be settled by arbitrators acceptable to both parties. Any one acting
+against these provisions shall be subject to canonical penalties. If any
+clerk have a complaint against his own bishop, he shall have his cause
+adjudicated upon by the synod of the province. But if a bishop or clerk
+have a difference with the metropolitan of his province let him bring it
+before the exarch of the "diocese" (i.e. the larger district answering
+to the civil "diocese"), or before the royal see of Constantinople, who
+shall do justice upon it. An "exarch" means properly a superior
+metropolitan having several provinces under him. In the next century
+Justinian (_Nov._ 123, c. 22) put the other patriarchates on the same
+footing as Constantinople. In c. 21 he gives either plaintiff or
+defendant an appeal within ten days to the secular judge of the locality
+from the bishop's judgment. If there be no appeal, that judge is to give
+execution to the episcopal award. The growth of a special "original"
+jurisdiction at Constantinople, which perhaps developed earlier than
+the corresponding institution at Rome, may be traced to the fact that
+bishops from all parts were constantly in Constantinople. The bishop of
+Constantinople, even before he became properly "patriarch," would often
+assemble a synod from these visiting bishops, which acquired the
+technical name of [Greek: synodos endemousa], the synod of sojourners.
+This synod frequently decided questions belonging to other
+patriarchates.
+
+The criminal jurisdiction thus exercised was generally speaking
+unlimited. It must be remembered that the _forum externum_ of the
+ecclesiastical jurisdiction, in the sense in which we now use the
+phrase, of a judge deciding causes, was not then clearly marked off from
+the _forum internum_, or what afterwards came to be called the "tribunal
+of penance" (see Van Espen, _Jus ecc. univ._ pars iii. tit. iv. c. 1).
+Ecclesiastical proceedings by way of prosecution are called "criminal,"
+but they are primarily _pro salute animae_; whereas temporal criminal
+proceedings are primarily for the protection of the state and its
+citizens. Hence a Christian might be first punished in the civil courts
+and then put to public penance by the ecclesiastical jurisdiction, or
+vice versa: an apparently double system of punishment which the medieval
+Church, when the _forum externum_ had become quite separated from the
+_forum internum_, sometimes repudiated (see Maitland, _English Canon
+Law_, 138, 139, 144).
+
+Theodosius began the system of giving secular authority to Church
+tribunals. Thus, in 376, L. 23 _Cod. Theodos. de. Episcopis_, &c.,
+subjected clerics for small offences pertaining to the observances of
+religion to bishops and synods. In 399, L. 1 _Cod. de Religione_
+provides that, when it is a matter of religion, it beseems the bishop to
+judge. A rescript of Constantius, in 355, inserted in _Cod. Theod._
+lxii. _de Epis. Ecc. et Cler._, excluded bishops from accusations before
+secular judges and commanded such accusations to be speedily brought
+before the tribunal of other bishops. This law was probably only
+intended to be of a temporary character. Then comes the law of Gratian
+already noticed. Then, in 399, a law of Honorius (_Cod. Theod._ L. 1 _de
+Religione_): "As often as it concerns religion, it is meet that the
+bishops should judge, but other causes which belong to ordinary
+jurisdiction or to public law are to be heard in the ordinary courts
+(_legibus oportet audiri_)." L. 3 _de Epis. Jud._, at the end of the
+Theodosian Code, seems spurious (see the comment of Gothofredus in
+loco). But a constitution of Honorius in 412 (_Cod. Theod._ L. xli. _de
+Epis. Ecc. et Cler._) provides that clerks are not to be accused except
+before the bishop. Bishops, priests, deacons, and every other "minister
+of the Christian law" of inferior degree, are taken from secular
+jurisdiction in criminal cases. The words are quite general; but it has
+been contended that they apply only to crimes of an ecclesiastical
+character (see Gothofredus in loc.; Van Espen, pars iii. tit. iii. c. 1,
+10). In 425 a constitution of Theodosius II. provides that a recent
+decree of the usurper John should be disregarded and that clerks whom he
+had brought before secular judges should be reserved for the episcopal
+jurisdictions, "since it is not lawful to subject the ministers of the
+divine office to the arbitrament of temporal powers." Justinian has a
+clearer perception of the demarcation between the spheres of spiritual
+and temporal law. The 83rd Novell provides that if the offence be
+ecclesiastical, needing ecclesiastical correction, the bishop shall take
+cognizance of it. The 123rd Novell (c. 21) provides that if a clerk be
+accused of a secular crime he shall be accused before his bishop, who
+may depose him from his office and order, and then the competent judge
+may take him and deal with him according to the laws. If the prosecutor
+have first brought him before the civil judge, the evidence is to be
+sent to the bishop, and the latter, if he thinks the crime has been
+committed, may deprive him of his office and order, and the judge shall
+apply to him the proper legal punishment. But if the bishop think the
+evidence insufficient, the affair shall be referred to the emperor, by
+way of appeal both from bishop and judge. If the cause be
+ecclesiastical, the civil judges are to take no part in the inquiry. The
+law includes with clerics, monks, deaconesses, nuns, ascetics; and the
+word "clerics" covered persons in minor orders, down to doorkeepers. It
+will be noticed that Justinian supposes that the prosecutor may begin
+the proceedings before the civil judge. A constitution of Alexius
+Comnenus I. seems to send him to the special forum of the accused.
+
+
+  Anglo-Saxon courts.
+
+Certain enactments of later Saxon times in England have been sometimes
+spoken of as though they united together the temporal and spiritual
+jurisdictions into one mixed tribunal deriving its authority from the
+State. In the latter part of the 10th century, laws of Edgar provided
+that the bishop should be at the county court and also the alderman, and
+that there each of them should put in use both God's laws and the
+world's law (Johnson's _English Canons_, i. 411). This probably was, as
+Johnson suggests, that the bishop might enforce secular laws by
+ecclesiastical censure and the alderman ecclesiastical laws with secular
+punishment. But the two jurisdictions were kept separate; for by another
+law of Edgar (_Leges Edg._ c. v.) it was provided that "in the most
+august assembly the bishop and alderman should be present, and the one
+should interpret to the people the law of God, the other the laws of
+men." Edgar, in a speech to St Dunstan and the bishops in synod (in
+969), said, "I hold in my hands the sword of Constantine, you that of
+Peter. Let us join right hands and unite sword to sword" (Hardouin,
+_Conc._ tom. vi. p. 1, col. 675). The juxtaposition of the judicatures
+may, however, have led to some confusion between them.
+
+As to appeals the mixed council of Cliff at Hoo (747) said they should
+go to the synod of the province. The only appeal to Rome in Saxon times
+was that of St Wilfrid, bishop of York, who appealed from the division
+of his see and his deposition for refusing to consent to it, and was
+heard in a Roman synod under the presidency of Pope Agatho. The synod
+found him unlawfully deposed and ordered his restoration. Upon his
+return to England, the Roman judgment was refused recognition and he was
+for a time imprisoned. Ten years later he was recalled to York, but
+refusing to consent to the division of his see was again deposed and
+again appealed to Rome. The appeal was heard at great length, in a synod
+of 703 under John VI., deputies from the archbishop of Canterbury being
+present. St Wilfrid was justified and was sent back to his see, with
+papal letters to the kings of Northumbria and Mercia. The Roman decree
+was again disregarded. At the council of "Nid" he was reconciled to the
+other bishops of the province, but not restored. In the end he was
+brought back to York, but not to the undivided see. The details of the
+case will be found in Wilkins, _Concilia_, in Mansi, _Concilia_, under
+the various councils named, and in Haddan & Stubbs, _Councils and Eccl.
+Documents_, vol. iii.
+
+
+  Penalties inflicted by ecclesiastical courts.
+
+The penalties which the spiritual court could inflict, in the period
+between the edict of Milan and c. 854, were properly excommunication
+whether generally or as exclusion from the sacraments for a term of
+months or years or till the day of death and (in the case of clerics)
+suspension or deposition. Gradually, however, doubtless by way of
+commutation of excommunication and of penance, temporal penalties were
+added, as scourging, banishment, seclusion in a monastery, fines. It is
+difficult to say how far some of these temporal penalties were
+penitential only or how far they could be inflicted _in invitos_. But
+the secular arm, from the time of Nicaea I., was in the habit of aiding
+spiritual decrees, as by banishing deposed bishops, and gradually by
+other ways, even with laymen. Scourging (although it had been a
+well-known punishment of the synagogue) was at first forbidden. Can. 28
+(26) of the Apostolic Canons imposes deposition on any bishop, priest or
+deacon striking the delinquent faithful. In Africa, however, a contrary
+practice early sprang up (see St Augustine, _Epist._ clix. _ad Marcellum
+al._ cxxxiii.). The small council of Vannes in Brittany in 465 made it
+an alternative punishment for clerks convicted of drunkenness (Can. 13).
+Canon 13 of the first council of Orleans, which has been cited in this
+matter, seems to have no application. St Gregory the Great seems to
+assume that scourging and seclusion in a monastery are in the discretion
+of episcopal tribunals (see _Epistles_, lib. ii. ep. 11, 40, 42, 44, 45;
+lib. vii. ep. 11, 67; lib. xii. ep. 31, c. 4). The 16th council of
+Toledo (in 693) has been cited as if it visited certain very great
+sinners with scourging as an ecclesiastical punishment. In fact, it only
+approves the punishment as ordered by the Visigothic laws. An alleged
+decree of a council of Autun in 670 is part of a code of discipline for
+monasteries (see authorities cited by Hefele, _Councils_, sect. 290,
+towards the end). Banishment does not seem to have been inflicted by the
+spiritual court _in invitum_. Seclusion in a monastery seems first to
+have been used by the civil power in aid of the spiritual. The fifth
+canon of the council of Macon, in 584, forbids clergy to dress like
+laymen and imposes a penalty of thirty days' imprisonment on bread and
+water; but this may be merely penitential. There is little evidence of
+the imposition of fines as ecclesiastical penalties; but there are
+references to the practice in the epistles of St Gregory the Great,
+notably in his instructions to St Augustine. Gregory III. copies from St
+Gregory I. Probably these also were by way of penance. Isolated examples
+in the early middle ages of metropolitans dealing with their suffragan
+bishops by imprisonment in chains were extra-canonical abuses, connected
+with the perversion of Church law which treated the metropolitan (who
+originally was merely convener of the provincial synod and its
+representative during the intervals of sessions) as the feudal "lord" of
+his comprovincials.
+
+With the later 9th century we enter upon a new epoch, and by the time of
+Gregory VII., in the 11th century, the tribunals have fallen into the
+hands of a regular class of canonists who are in fact professional
+church-lawyers in orders. The changes due to the adoption of the False
+Decretals by Nicholas I. and the application of their principles by
+Hildebrand (afterwards Gregory VII.) are discussed in the article CANON
+LAW. The later medieval system, thus inaugurated, may be considered (1)
+in its hierarchy, (2) in the subject matter of its jurisdiction, (3) in
+its penalties.
+
+
+  Later medieval system.
+
+1. (a) It is a system of courts. Much that had been done by bishops,
+_sine strepitu forensi et figura judicii_, is now done in the course of
+regular judicial procedure. Again, the court takes the place of the
+synod. The diocesan synod ceases to have judicial work. The court of the
+metropolitan takes the place of the provincial synod, except possibly
+for the trial of bishops, and even this becomes doubtful.
+
+(b) At first the bishop was the only judge in the diocesan court and he
+always remains a judge. But just as the king appoints judges to hear
+_placita coram rege ipso_, and the feudal lord appoints his seneschal or
+steward, so the bishop appoints his official.
+
+(c) The archdeacon acquires a concurrent ordinary jurisdiction with the
+bishop (see ARCHDEACON). For some time it was considered that he was a
+mere office-holder dependent on the will of the bishop with a
+jurisdiction merely "vicarial"; but by the 13th century it was settled
+that he held a "benefice" and that his jurisdiction over causes was
+ordinary and independent of the bishop (Van Espen, pars i. tit. xii. c.
+1; Fournier, _Les Officialites au moyen age_, p. 134). It was partly in
+order to counterpoise the power of archdeacons that bishops created
+officials (Fournier, p. 8). Archdeacons in course of time created
+officials who presided in court in their stead. The extent of
+jurisdiction of archdeacons depended much upon local customs. In England
+the custom was generally in their favour. Ordinarily, the appeal from an
+archdeacon or his official lay to the court of the bishop; but by custom
+the appeal might be to the court of the metropolitan: The Constitutions
+of Clarendon, in 1164, made the appeal from the court of the archdeacon
+lie to the court of the bishop.
+
+(d) The official of the bishop might be his official principal, who was
+his _alter ego_, or a special officer for a particular locality
+(_officialis foraneus_). The latter was treated as a mere delegate, from
+whom an appeal could be made to the bishop. The former had one
+consistory with the bishop, so that appeals from him had to be made to
+the court of the metropolitan. How far the official principal had
+jurisdiction in criminal matters by virtue of his office, how far it was
+usual to add this jurisdiction by special commission, and what were the
+respective limits of his office and that of the vicar-general, are
+questions of some nicety. The emphasis in Italy was on the vicar-general
+(_Sext. de officio Vicarii_). In the Low Countries, France and England
+the jurisdiction of the official principal was wider (Van Espen, pars
+i. tit. xii. cc. 4, 5; Fournier, p. 21). But he could not try criminal
+matters unless specially committed to him (Lyndwood, _Provinciale_, lib.
+ii. tit. 1). Later in England it became usual to appoint one man to the
+two offices and to call him chancellor, a word perhaps borrowed from
+cathedral chapters, and not in use for a diocesan officer till the time
+of Henry VIII. or later (see CHANCELLOR). In Ireland the title, till the
+church was disestablished, was vicar-general.
+
+The importance of distinguishing the normal functions of an official
+principal and a vicar-general lies in this: that it was gradually
+established that as a king should not hear causes but commit them to his
+judges, so a bishop should not hear causes but appoint an official to
+hear them (see Ridley, _View of the Civil and Eccl. Law_; Ayliffe,
+_Parergon juris ecclesiastici_, p. 161; Godolphin, _Abridgement of the
+Laws Ecclesiastical_, p. 8). The "parlements" of France were constantly
+insisting on the independence and irremovability of the official
+(Fournier, p. 219). But jurisdiction which was not necessarily incident
+to the office of the official principal, that is to say voluntary
+jurisdiction, such as the granting of licences and institution to
+benefices, and criminal jurisdiction over clerks (and probably over
+laymen), the bishop could reserve to himself. Reservations of this
+nature are made in many English patents of chancellors and were held
+good in _R._ v. _Tristram_, 1902, 1 K.B. 816.
+
+(e) The ecclesiastical and temporal courts are kept distinct. The
+charter of William the Conqueror abrogated the laws of Edgar. No bishop
+or archdeacon "shall any longer hold pleas in the Hundred concerning
+episcopal law nor draw a cause which concerns the rule of such to the
+judgment of men of the world" (Stubbs, _Select Charters_, part iii.). In
+France, where the bishop was a temporal baron, his feudal and his
+spiritual courts were kept by distinct officers (Fournier, p. 2).
+
+(f) From the bishop, or his official, appeal lay to the metropolitan,
+who again could hear causes by his official. The Constitutions of
+Clarendon recognize this appeal (c. viii.).
+
+(g) An appeal lay from the court of the metropolitan to that of the
+primate. There were many disputes as to the existence of these primates
+(see Maitland, _Canon Law in the Church of England_, p. 121). In England
+the dispute between Canterbury and York was settled by making them both
+primates, giving Canterbury the further honour of being primate of all
+England. In France the primatial sees and the course of appeals to them
+were well established (Fournier, p. 219).
+
+(h) Several attempts were made by metropolitans and their officials to
+take causes arising in the dioceses of their comprovincials in the first
+instance and not by way of appeal. The officials of primates in their
+turn made similar attempts. After long struggles this was hindered, in
+France by the bull _Romana_ (Fournier, p. 218), in England by the Bill
+of Citations, 23 Henry VIII. c. 9, and Canon 94 of the Canons of 1603.
+The preamble of the "Bill of Citations" is eloquent as to the mischief
+which it is framed to prevent. There are, however, a few cases in which
+the metropolitan is still allowed to cite in the first instance. One of
+them was in cases of "perplexity." "Perplexity" arose where the
+suffragans "could not owing to the geographical limitations of their
+competence do full justice" (Maitland, pp. 118-119). Such was the case
+of probate where notable goods of the deceased lay in more than one
+diocese. Hence the origin of the "prerogative court" of Canterbury (cf.
+Van Espen, pars i. tit. xix.; and for Spain, Covarruvias, _Pract.
+Quaest._ c. 9).
+
+(i) Gradually there grew up a mass of peculiar and exempt jurisdictions
+(Ayliffe, pp. 417, 418; Phillimore, Eccl. Law, pp. 214, 927; de
+Maillane, _Dict. du droit canonique_, s.v. "Exemptions"). Exempt
+jurisdictions began with the monasteries and were matter of vehement
+discussion in the later middle ages. There were no true exemptions
+before the 11th century (Van Espen, pars iii. tit. xii.). Peculiar or
+special jurisdiction, equal to that of the bishop, was given to deans
+and chapters over the cathedral precincts and in places where they had
+corporate property (see _Parham_ v. _Templer_, 3 Phil. Ecc. R. 22).
+Sometimes it was given to deans alone or to prebendaries in the parishes
+whence they derived their prebends. Where the archdeacon had a
+jurisdiction co-ordinate with the bishop, it was called a peculiar. The
+metropolitans had peculiars within the dioceses of their comprovincials
+wherever they had residences or manors, and some whose origin is
+uncertain, e.g. that of the fifteen parishes in the deanery of the
+Arches. The official administering justice for the metropolitan was
+usually called a dean. From a peculiar jurisdiction ranking as episcopal
+the appeal lay to the court of the metropolitan. As to metropolitan
+peculiars, the metropolitan might give an appeal from the dean to his
+regular official principal. Thus, in Canterbury there was an appeal from
+the dean of Arches to the official principal of the Arches court. When
+peculiars were abolished (_vide infra_) the dean of Arches disappeared,
+and his title, in the 19th century, was erroneously given to the
+official principal. On peculiars in Spain cf. Covarruvias, _Works_, tit.
+i. p. 410. The French parlements, after the middle ages, discouraged
+them. In exempt convents the head of the monastery or priory exercised
+jurisdiction subject to an appeal to the pope.
+
+(j) It is said that originally a metropolitan had only one official
+principal, who, like the metropolitan himself, acted both for the
+diocese and province. Fournier (p. 219) says that in France it was not
+till the 17th century that there grew up a custom of having different
+officials for the metropolitan, one for him as bishop, a second as
+metropolitan, and even a third as primate, with an appeal from one to
+the other, and that it was an abuse due to the parlements which strove
+to make the official independent of the bishop. In England there has
+been, for a long time, a separate diocesan court of Canterbury held
+before the "commissary." The word is significant as showing that there
+was something special and restricted about the position. In York there
+are two courts, one called the consistory for the diocese, the other
+called the chancery for the province. But the same person was often
+official of both courts.
+
+(k) In England the Constitutions of Clarendon added a provision for
+appeal to the king, "and if the archbishop shall have failed in doing
+justice recourse is to be had in the last resort (_postremo_) to our
+lord the king, that by his writ the controversy may be ended in the
+court of the archbishop; because there must be no further process
+without the assent of our lord the king." The last words were an attempt
+to limit further appeal to Rome. It will be observed that the king does
+not hear the cause or adjudicate upon it. He merely corrects slackness
+or lack of doing justice (_Si archiepiscopus defecerit in justitia
+exhibenda_) and by his writ (_precepto_) directs the controversy to be
+determined in the metropolitan's court. As bishop Stubbs says (_Report
+of Eccl. Comm._ vol. i. _Hist. App._ i.): "The appeal to the king is
+merely a provision for a rehearing before the archbishop, such failure
+to do justice being not so much applicable to an unfair decision as to
+the delays or refusal to proceed common at that time" (cf. Joyce, _The
+Sword and the Keys_, 2nd ed. pp. 19-20). The _recursus ad principem_, in
+some form or other of appeal or application to the sovereign or his lay
+judges, was at the end of the middle ages well known over western
+Europe. This recourse in England sometimes took the form of the appeal
+to the king given by the Constitutions of Clarendon, just mentioned, and
+later by the acts of Henry VIII.; sometimes that of suing for writs of
+_prohibition_ or _mandamus_, which were granted by the king's judges,
+either to restrain excess of jurisdiction, or to compel the spiritual
+judge to exercise jurisdiction in cases where it seemed to the temporal
+court that he was failing in his duty. The _appellatio tanquam ab abusu_
+(_appel comme d'abus_) in France was an application of a like nature.
+Such an appeal lay even in cases where there was a refusal to exercise
+voluntary jurisdiction (de Maillane, _Dictionnaire du droit canonique_,
+tit. "Abus," cf. tit. "Appel"). This writer traces their origin to the
+14th century; but the procedure does not seem to have become regularized
+or common till the reigns of Louis XII. or Francis I. (cf. _Dict.
+eccl._, Paris, 1765, titt. "Abus" and "Appel comme d'abus"). On the
+_recursus ad principem_ and the practice of "cassation" in Belgium,
+Germany and Spain, cf. Van Espen's treatise under this title (_Works_,
+vol. iv.) and _Jus eccles. univ._ pars iii. tit. x. c. 4. Louis XIV.
+forbad the parlements to give judgment themselves in causes upon an
+_appel comme d'abus_. They had to declare the proceedings null and
+abusive and command the court Christian to render right judgment (Edict
+of 1695, arts. 34, 36, cited in Gaudry, _Traite de la legislation des
+cultes_, Paris, 1854, tom. i. pp. 368, 369).
+
+In Catalonia "Pragmatics," letters from the prince, issued to restrain
+jurisdiction assumed by ecclesiastical judges contrary to the customs of
+the principality. Thus in 1368 Peter III. evoked to the royal court a
+prosecution for abduction pending before the archbishop of Tarragona,
+declaring that the archbishop and the official were incompetent to judge
+noblemen. See this and other instances collected in _Usages y demas
+derechos de Cataluna_, by Vives y Cebria (Barcelona, 1835), tom. iv. p.
+137 et seq.
+
+(l) Lastly there was the appeal to the patriarchs, i.e. in the West to
+Rome. The distinguishing feature of this appeal was that the rule of the
+other appeals did not apply to it. In the regular course of those
+appeals an appellant could not leap the intermediate stages; but he
+could at any stage go to this final appeal, _omisso medio_, as it was
+technically called (see _de appell. c. Dilect._ iii. for general rule,
+and c. 3 _de appell._ in 6 for different rule in case of the pope, and
+authorities cited in Van Espen, pars iii, tit. x. c. 2, 5). Van Espen
+says: "The whole right of appeal to the Roman pontiff _omisso medio_ had
+undoubtedly its origin in this principle, that the Roman pontiff is
+ordinary of ordinaries, or, in other words, has immediate episcopal
+authority in all particular churches, and this principle had its own
+beginning from the False Decretals."
+
+Appeals to Rome lay from interlocutory as well as final judgments.
+Causes could even be evoked to Rome before any judgment and there heard
+in first instance (Van Espen, pars iii. tit. x. c. 1, 8).
+
+There was an alleged original jurisdiction of the pope, which he
+exercised sometimes by permanent legates, whom Gregory VII. and his
+successors established in the chief countries of Europe, and to whom
+were committed the legislative executive and judicial powers of the
+spiritual "prince" in the districts assigned to them. These Clement IV.
+likened to "pro-consuls" and declared to have "ordinary" jurisdiction;
+because they had jurisdiction over every kind of cause, without any
+special delegation, in a certain defined area or province (c. ii. _de
+Officio Legati_ in 6). They were expressed to have not merely appellate
+but original jurisdiction over causes (iii. c. i. _de Officio Legati_).
+The occupants of certain sees by a kind of prescription became legates
+without special appointment, _legati nati_, as in the case of
+Canterbury. In the 13th century Archbishop Peckham, says Maitland (p.
+117), as archbishop "asserted for himself and his official (1) a general
+right to entertain in the first instance complaints made against his
+suffragans' subjects, and (2) a general right to hear appeals _omisso
+medio_." It was, for the time, determined that the archbishop might
+himself, in virtue of his legatine authority, entertain complaints from
+other dioceses in first instance, but that this legatine jurisdiction
+was not included in the ordinary jurisdiction of his official principal,
+even if the archbishop had so willed it in his commission. In fact,
+however, the official did before the end of the later medieval period
+get the same power as the archbishop (Maitland, pp. 118-120; cf.
+Lyndwood, lib. v. tit. 1), till it was taken from him by the Bill of
+Citations.
+
+After legates came special delegates appointed by the pope to hear a
+particular cause. It was the general practice to appoint two or three to
+sit together (Van Espen, pars iii. tit. v. c. 2, 37). These might
+sub-delegate the whole cause or any part of it as they pleased, ibid.
+9-18. Dr Maitland (essay on "The Universal Ordinary") thinks, but
+without very much foundation, that great numbers especially of the more
+important causes were tried before these delegates; although the records
+have largely perished, since they were the records of courts which were
+dissolved as soon as their single cause had been decided. These courts
+were convenient, since it was the custom to appoint delegates resident
+in the neighbourhood, and the power of sub-delegation, general or
+limited, simplified questions of distance. In Belgium causes appealed
+to Rome had to be committed to local delegates (Van Espen, pars iii.
+tit. v. c. 3, tit. x. c. 2).
+
+There could be an appeal from these delegates to the pope and from the
+pope himself to the pope "better informed" (Van Espen, pars iii. tit. x.
+c. 2, 12, 13). So personal had the system of jurisdiction become that
+even the trials of bishops ceased to be necessarily conciliar. Generally
+they were reserved to the pope (Van Espen, pars iii. tit. iii. c. 5,
+17-19); but in England the archbishop, either in synod, or with some of
+his comprovincial bishops concurring, tried and deposed bishops (see
+case of Bishop Peacock and the other cases cited in _Read_ v. _Bishop of
+Lincoln_, 14 P.D. 148, and Phillimore, _Eccl. Law_, pp. 66 et seq.).
+
+(m) The jurisdiction of a bishop _sede vacante_ passed, by general law,
+to the dean and chapter; but in England the metropolitans became
+"guardians" of the spiritualities and exercised original jurisdiction
+through the vacant diocese (Phillimore, pp. 62-63), except in the case
+of Durham, and with a peculiar arrangement as to Lincoln.
+
+If the metropolitan see were vacant the jurisdiction was exercised by
+the dean and chapter through an official (Rothery, _Return of Cases
+before Delegates_, Nos. 4, 5). As to France see Fournier, p. 294.
+
+(n) Officials, even of bishops and metropolitans, need not be in holy
+orders, though Bishop Stubbs in his paper in the _Report of the
+Commission on Ecclesiastical Courts_ seems to say so. They had to be
+clerics, that is, to have received the tonsure. Even papal delegates
+might be simple clerks (Van Espen, pars iii. tit. v. c. 2, 20).
+
+It came, however, to be the practice to impose some restrictions, as on
+clerks twice married. Thus Archbishop Chichele provided that no clerk
+married or bigamous (that is, having had two wives in succession) should
+exercise spiritual jurisdiction (see Lyndwood, lib. iii. tit. 3). Abroad
+unsuccessful attempts were made by local councils to enact that
+officials and vicars-general should be in holy orders (Hefele on
+Councils of Tortosa in 1429 and Sixth of Milan in 1582). These councils,
+as will be seen, are late.
+
+(o) With or without the concurrence and goodwill of the national Church,
+restrictions were imposed by the State on the papal jurisdiction,
+whether original or appellate. In England the Constitutions of Clarendon
+(by chap. viii.) prohibited appeals to the pope; but after the murder of
+St Thomas of Canterbury Henry II. had to promise not to enforce them.
+The statutes 38 Edw. III. st. 2, 13 Rich. II. st. 2, c. 2, and 16 Rich.
+II. c. 5 forbid such appeals; but it is suggested that notwithstanding
+the generality of their language they refer only to cases of temporal
+cognizance. Cases upon the execution of these statutes are collected in
+Stillingfleet, _On Ecclesiastical Jurisdiction_, p. 189; Gibson,
+_Codex_, 83. Obstacles were placed in the way of appeals to the pope
+_omisso medio_. Thus when a writ of _significavit_ issued on the mandate
+of a bishop, an appeal to Rome availed not to stay execution; but if
+there were an appeal to the archbishop it was otherwise. It therefore
+became the custom to lodge a double appeal: one to the archbishop "for
+defence," and the other to the pope as the real appeal ("Hostiensis,"
+_Super Decret._ ii. fol. 169; cf. Owen, _Institutes of Canon Law_, 1884,
+pt. i. c. 19, 5).
+
+There seems to have been no machinery for assisting the original or
+appellate jurisdiction of the pope by secular process,--by
+_significavit_ or otherwise.
+
+The matrimonial cause between Henry VIII. and Catharine of Aragon was
+the most famous English cause tried by delegates under the "original"
+jurisdiction of the pope, and was ultimately "evoked" to Rome. The
+foreseen adverse termination of this long-drawn cause led to Henry's
+legislation.
+
+When the temporal courts interfered to prevent excess of jurisdiction,
+they did so by prohibiting the ecclesiastical court from trying and the
+suitor from suing in that court. The pope could not be effectively
+prohibited, and no instance is recorded of a prohibition to papal
+delegates. But suitors have been prohibited from appealing to the pope
+(see per Willes, J., in _Mayor of London_ v. _Cox_, L.R. 2 H.L. 280).
+Whatever may have been the law, it is certain that, notwithstanding the
+statutes of Edw. III. and Rich. II., appeals to Rome and original trials
+by papal delegates did go on, perhaps with the king's licence; for the
+statute 24 Hen. VIII. c. 12 recites that the hearing of appeals was an
+usurpation by the pope and a grievous abuse, and proceeds to take away
+the appeal in matrimonial, testamentary and tithe causes, and to hinder
+by forbidding citation and process from Rome, all original hearings
+also. The statute 25 Hen. VIII. c. 19 follows this up by taking away
+appeals in all other subjects of ecclesiastical jurisdiction.
+
+In 1438 the council of Basel took away all papal original jurisdiction
+(save in certain reserved cases--of which _infra_), evocation of causes
+to Rome, appeals to Rome _omisso medio_, and appeals to Rome altogether
+in many causes. Such appeals when permissible, except the "greater,"
+were to be tried by delegates on the spot (31st Session; Mansi,
+_Concilia, in loco_). These proceedings at Basel were regarded at Rome
+as of no effect. Nevertheless this decree and others were adopted by a
+French national council at Bourges and promulgated by the king as a
+"Pragmatic Sanction" (Migne, _Dict. du droit canonique_, "Pragmatique
+Sanction"). The parlements registered the Sanction and the effect was
+permanent in France. Louis XI. and Charles VIII. sought to revoke it;
+but both parlements and states-general refused to recognize the revoking
+decrees. In 1499 Louis XII. ordered the Pragmatic to be inviolably
+observed. The parlements thereupon condemned several private persons for
+obtaining bulls from Rome. In 1516 a Concordat between Leo X. and
+Francis I. settled all these questions in the sense of the Pragmatic,
+substantially according to the Basel canon. All causes, except the
+"greater," were to be terminated in the country where the proper
+cognizance would lie (Migne, op. cit. "Concordat"). By this Concordat,
+by an ordinance of Francis I. in 1539, by two or three other royal
+edicts, and (above all) by the practice of the parlements, explanatory
+of this legislation, and their _arrets_, the conflict of secular and
+ecclesiastical jurisdictions was settled until the Revolution (Migne,
+_ubi sup._). "Greater causes" came in France to be restricted to
+criminal prosecutions of bishops. Even in these the original
+jurisdiction of the pope was taken away. In first instance they were
+tried by the provincial synod. Thence there was appeal to the pope (de
+Maillane, op. cit. s.v. "Causes majeures"; _Dict. eccl._, Paris, 1765,
+s.v. "Cause"). The only original jurisdiction left to the pope was in
+the case of the matrimonial causes of princes. But they could only be
+heard on the spot by judges delegate. Examples are the causes of Louis
+XII. and Jeanne of France in 1498, and of Henry IV. and Marguerite of
+Valois in 1599 (Migne, op. cit. s.v. "Causes"). The prohibition of papal
+interference was enforced if necessary by the _appel comme d'abus_
+(_vide supra_). Out of respect for the pope this appeal was not brought
+against his decrees but against their execution (_Dict. eccl._, Paris,
+1765, s.v. "Abus").
+
+Spain appears to have permitted and recognized appeals to the pope. A
+royal writ of the 16th century cited by Covarruvias (c. xxxv.) prohibits
+execution of the sentence of a Spanish court Christian pending an appeal
+to the pope.
+
+
+  Civil jurisdiction.
+
+2. The subject matter over which the ecclesiastical courts had
+jurisdiction was no longer purely "criminal" with a civil
+quasi-jurisdiction by way of arbitration. In the later middle ages these
+courts had jurisdiction over most questions, except indeed the then most
+important ones, those relating to real property. This civil jurisdiction
+was sometimes concurrent with that of the secular courts, sometimes
+exclusive. For England it may be thus classified:--
+
+(a) _Matrimonial._--This arose naturally from the sacred character of
+Christian marriage. This jurisdiction was exclusive. From it followed
+the right of the courts Christian to pronounce upon questions of
+legitimacy. Upon this right an inroad was early made, in consequence of
+the question of legitimation by subsequent marriage. In the 12th century
+the Church's rule, that subsequent marriage did legitimize previous
+issue, was settled (c. 6, x. 4, 17). The king's judges then began to ask
+the ordinary the specific question whether A. B. was born before or
+after his parents' marriage. After the inconclusive proceedings at the
+realm-council of Merton (1236), when spiritual and temporal lords took
+opposite views, the king's judges went a step further and thenceforward
+submitted this particular question to a jury. All other questions of
+legitimacy arising in the king's courts were still sent for trial to the
+bishop and concluded by his certificate (see Pollock and Maitland,
+_Hist. Eng. Law before Edward I._ vol. i. 105-106; Maitland, _ubi
+supra_, pp. 53-56).
+
+(b) _Testamentary and in regard to succession from intestates._--Real
+property was not the subject of will or testament in the medieval
+period. But as to personal property, the jurisdiction of the courts
+Christian became exclusive in England. The Church, East and West, had
+long asserted a right to supervise those legacies which were devoted to
+pious uses, a right recognized by Justinian (_Cod._ i. 3. 46). The
+bishop or, failing him, the metropolitan, was to see such legacies
+properly paid and applied and might appoint persons to administer the
+funds (Pollock and Maitland, op. cit. ii. 330). This right and duty
+became a jurisdiction in all testamentary causes. Intestacy was regarded
+with the greatest horror, because of the danger to the intestate's soul
+from a death without a fitting part given to pious uses (Maine, _Ancient
+Law_, ed. 1906, note by Pollock, p. 230; cf. Pollock and Maitland, op.
+cit. ii. 354). Hence came the jurisdiction of the ordinary in intestacy,
+for the peace of the soul of the departed. This head of ecclesiastical
+jurisdiction was in England not transferred to the secular court till
+1857.
+
+(c) _Church Lands._--If undoubtedly held in _frankalmoign_ or "free
+alms," by a "spiritual" tenure only, the claim of jurisdiction for the
+ecclesiastical _forum_ seems to have been at first conceded. But the
+Constitutions of Clarendon (c. 9) reserved the preliminary question, of
+"frankalmoign" or not, for a jury in the king's court. Then, if the
+tenure were found free alms, the plea was to be heard in the court
+Christian. From the 13th century, however, inclusive, the king's courts
+insisted on their exclusive jurisdiction in regard to all realty,
+temporal or "spiritual" (Pollock and Maitland, op. cit. i. 106).
+
+(d) _Title to present to and possession of benefices._--As to the title
+to present to benefices, the courts Christian at one time had concurrent
+jurisdiction with the temporal courts. "Advowsons" were, however, looked
+upon as a species of "real" property in England, and therefore the
+king's court early claimed exclusive jurisdiction in disputes where the
+title to present was involved. The Constitutions of Clarendon provided
+that these causes should be heard only in the king's court (c. 1). This
+rule was applied even where both litigants were "spiritual." In the 13th
+century abbots sue each other in the royal court for advowsons (Selden
+Soc. _Select Civil Pleas_, i. pl. 245). In 1231, in such a suit, the
+bishop of London accepts wager of battle (Pollock and Maitland, op. cit.
+i. 105). In cases, however, where the title to present was not in
+question, but the fitness of the clerk presented, or, in cases of
+election to benefices, the validity of the election, there was
+jurisdiction in the courts Christian.
+
+(e) _The recovery of tithes and church dues,_ including in England
+church rates levied to repair or improve churches and churchyards.
+
+(f) Questions concerning _fabrics, ornaments, ritual and ceremonial_ of
+churches.
+
+(g) _Administration of pious gifts and revenues given to prelates or
+convents._--Their right application could be effectively enforced only
+in the courts Christian; until the rise in England of the equitable
+jurisdiction of the court of chancery and the development of the
+doctrine of "uses" at the end of the middle ages.
+
+(h) _Enforcement of contractual promises made by oath or pledge of
+faith._--The breaking of such a promissory oath was called "perjury" (as
+in classical Latin and in Shakespeare), contrary to modern usage which
+confines the word to false evidence before a court of justice. In regard
+to the execution of these promises, the jurisdiction of the
+ecclesiastical courts was possibly traversed by c. 15 of the
+Constitutions of Clarendon; but allowed by the statute 13 Edw. I. st. 4.
+As just intimated, besides the enforcement of the promise, the
+"perjury" was treated as an ecclesiastical crime.
+
+The _criminal jurisdiction of courts Christian over laymen_ included,
+besides these "perjuries," (a) all _sexual offences_ not punishable on
+indictment; (b) _Defamation of character_ (the king's courts came in
+time to limit this to such defamation as could not be made the subject
+of a temporal action); (c) _Offences by laymen against clerks_ (i.e.
+against all "tonsured" persons, supra); (d) _Offences in regard to holy
+places_--"brawling" and such like; (e) _Heresy, schism, apostasy,
+witchcraft_.
+
+In regard to "clerks," there was (1) all the criminal jurisdiction which
+existed over laymen, and (2) criminal jurisdiction in regard to
+professional misconduct. Concerning "felonious" clerks the great
+questions discussed were whether the courts Christian had exclusive
+jurisdiction or the king's court, or whether there was a concurrent
+jurisdiction. The subject was dealt with in the Constitutions of
+Clarendon, formally revoked after the murder of St Thomas of Canterbury.
+In the 13th century it was recognized that a "clerk" for felony was
+subject only to ecclesiastical trial and punishment; punishment which
+might involve lifelong imprisonment. For "misdemeanours," as yet
+unimportant, he had no exemption from secular jurisdiction (Pollock and
+Maitland, op. cit. ch. iv.). At some indeterminate later period, the
+"clerk" was tried for felony by a jury in the king's court and then
+"pleaded his clergy," after conviction there, and was remitted to the
+ordinary for ecclesiastical punishment. "Clerks" for the purpose of
+"benefit of clergy" included not only persons in minor orders, but all
+"religious" persons, i.e. monks, friars, nuns, &c. Later the custom
+arose of taking "clerk" to include any "literate," even if not in orders
+or "religious" (cf. Stephen, _Hist. Crim. Law_, i. 461). The statute 4
+Hen. VII. c. 13 took away benefit of clergy, if claimed a second time,
+from persons not "within orders," in certain bad cases. 4 Hen. VIII. c.
+2 (a temporary act) took away "clergy," in certain heinous crimes, from
+all persons not in "holy" orders. This statute was partly renewed by 22
+Hen. VIII. c. 13. Other changes were introduced by 23 Hen. VIII. c. 1
+and later acts. In time, "benefit of clergy" became entirely diverted
+from its original objects.
+
+In _France_, till 1329, there seems to have been no clear line of
+demarcation between secular and ecclesiastical jurisdictions. Beaumanoir
+(_Coutume de Baulvoisis_, ch. xi., cited Gaudry, op. cit. i. 22) had
+laid down the principle that spiritual justice should meddle only with
+spiritual things. In the year named the secular courts complained to the
+king, Philip of Valois, of the encroachments of the courts Christian.
+The "cause" was solemnly argued before that monarch, who decided to
+leave things as they were (Migne, _Dict. du droit canon._, s.v.
+"Officialites"). In 1371 Charles V. forbade spiritual courts to take
+cognizance of "real" and "possessory" actions even in regard to clerks
+(Migne, loc. cit.; cf. Gaudry, _ubi sup._). From this period the
+parlements began the procedure which, after the Pragmatic Sanction of
+Charles VII., in 1438 took regular shape as the _appel comme d' abus_
+(_supra_; Migne, loc. cit.). Testamentary causes at first were subject
+to the concurrent jurisdiction of the spiritual and secular courts.
+After the 14th century, the latter had exclusive jurisdiction (Van
+Espen, op. cit. lib. iii. tit. ii. cc. 2, 15, 16). In regard to
+_marriage_ the secular jurists distinguished between the civil contract
+and the sacrament, for purposes of separating the jurisdiction (_Dict.
+eccl._, Paris, 1765, s.v. "Mariage"). The voluntary jurisdiction as
+regards dispensations was kept for the Church. The contentious
+jurisdiction of the courts Christian was confined to promises of
+marriage, nullity of marriage caused by "diriment" impediments only,
+validity or invalidity of the sacrament, divorce _a thoro_ (ibid.).
+Questions in regard to the _property in a benefice_ were for the courts
+Christian; in regard to its _possession_, for the king's courts. But if
+a "possessory" action had been brought in the latter, a subsequent suit
+in the courts spiritual for the property was deemed "abusive" and
+restrained (ib., s.v. "Petitoire") _Breach of faith or of promise
+confirmed by oath_ was matter for the court Christian (Fournier, pp. 95,
+99, 109, 125). This branch of jurisdiction was larger and more freely
+used than in England (cf. Pollock and Maitland, op. cit., as to
+Normandy). The only other remaining civil jurisdiction of the
+ecclesiastical courts was in _personal actions where clerks were
+defendants_ (Migne, op. cit., s.v. "Officialites," Fournier, pp.
+65-125); or, after the 14th century, where both parties were clerks. In
+regard to crimes delicts (_delits_) were divided into classes for
+purposes of jurisdiction. Clerks were punishable only in the court
+Christian, except in cases of grave crimes such as murder, mutilation
+(Fournier, p. 72), and cases called "royal cases" (_vide infra_). Laymen
+were punishable in the court Christian for the _delits_ following:
+injury to sacred or religious places, sacrilege, heresy (except where it
+was a "royal case"), sorcery, magic, blasphemy (also punishable in the
+secular court), adultery, simony, usury and infractions of the truce of
+God (Fournier, pp. 90-93). What were called "privileged delicts" were
+judged in the case of the clergy conjointly by the spiritual judge and
+the king's judge. Bishops had no exemption (_Dict. ecc._, s.v. "Delits,"
+"Cas privilegie," "Causes majeures"). "Royal cases" included such crimes
+as touched the prince, as all forms of treason; or the dignity of his
+officers; or the public safety. In this class were also included such
+heresies as troubled the state, as by forbidden assemblies, or by
+teaching prohibited doctrine. Among these heresies were reckoned
+idolatry, atheism, Protestantism, relapse (_ib. et_ "Cas royaux,"
+"Heresie"). These were of exclusive royal jurisdiction as against both
+spiritual courts and the courts of feudal lords. A similar claim was
+made by Pombal for Portugal (_vide infra_).
+
+The parlements, in order to have a ready means of enforcing all these
+restrictions by _appel comme d'abus_, compelled the bishops to appoint
+officials, Frenchmen, graduates, and (as it seems) "seculars" (_Dict.
+eccl._, Paris, 1765, s.v. "Official"). This last qualification was
+disputed (see Fevret, _Traite de l'abus_).
+
+3. _Punishments._--Ecclesiastical sanctions were divided into
+_punishments_ (_poenae_), either purely temporal in character or else of
+a mixed spiritual and temporal character, and _censures_ (_censurae_),
+purely spiritual and remedial (see Van Espen, pars iii. tit. xl. cc. 1,
+3; Phillimore, _Ecclesiastical Law_, p. 1064). In the book last cited
+_censurae_ and _poenae_ are classed together as "censures" (which is the
+modern use).
+
+_Poenae._--(a) Fines sprang from the older custom of directing alms by
+way of penance in the internal forum (Van Espen, _ubi sup._ c. 1, 5-10).
+They were to be applied to pious uses. (b) _Reclusion in a monastery_
+continued from former period, and might be either temporary or perpetual
+(loc. cit. 17-19). (c) _Imprisonment_, in the bishop's prison, might be
+in chains, or on bread and water, and temporary or perpetual. In its
+severer forms it was only inflicted for more atrocious crimes which the
+secular law would have punished with death (loc. cit. 21-27). The act 23
+Henry VIII. c. 11 made special provision for convicted clerks who broke
+out of the prisons of the ordinary. (d) _Fustigation_, as in former
+period, was hardly an ecclesiastical punishment. If given, it was to be
+of a paternal character (loc. cit. 39-45). Punishments of a mixed nature
+were: (e) _Suspension_ either from office alone or from office and
+benefice; (f) _Deprivation_ of benefice; (g) _Deposition_ or
+_Degradation_ (a more solemn and ceremonial form) from the ministry; (h)
+_Irregularity_--not always a punishment--a state of incapacity to be
+ordained, or, being ordained, to execute the ministry; this might result
+from some defect of mind and body, but was also incurred by some grave
+offences.
+
+_Censures_ were as follows: (i) _Suspension_ from attending divine
+offices or _ab ingressu ecclesiae_, more appropriate for a layman. A
+clerk in like case might be suspended from office. (j) _Interdict_ was
+another form of partial or total suspension from the benefit of the
+rites and sacraments of the Church. An interdict might be personal or
+local (see INTERDICT). (k) _Excommunication_ was either greater or less.
+The greater separated entirely from the Church. It might be pronounced
+under anathema. The less deprived of participation in the sacraments,
+and made a clerk incapable of taking a benefice.
+
+On the European continent the courts Christian often carried out their
+decrees by their own apparitors who could levy pecuniary penalties on a
+defendant's goods (Van Espen, pars iii. tit. ix. c. 4). They could
+arrest and imprison. In England, except in the peculiar case of
+imprisonment pending trial for heresy, or in the case of a clerk
+convicted of crime, these things could not be. The sentence of the court
+Christian had in all other cases to be enforced by the secular arm.
+Early in Henry II.'s time it had become the custom of England for the
+court Christian to "signify" its sentence of excommunication to the king
+and to demand from him a writ of _significavit_ to the sheriff, to
+imprison the person excommunicated. The writ apparently issued for no
+court inferior to the bishop's, unless upon the bishop's request. In
+some sense the king's writ of _significavit_ was discretionary; but its
+issue could be enforced by excommunication or interdict.
+
+In the cases of heresy, apostasy and sorcery, the spiritual courts
+sought the aid of the secular jurisdiction to superadd the punishment of
+death. Incorrigible offenders on these matters were "left" to the
+secular power, to be corrected with due "animadversion." This provision
+of the fourth Lateran Council in 1215 was always interpreted to mean
+death (see Van Espen, _Observ. in Conc. Lat. IV. Canones_, and the
+decree in the _Sext. ut inquisitionis negotium_; and, as to English law
+and practice, Maitland, op. cit., Essay vi., and pp. 161, 176; 2 Hen.
+IV. c. 15; Fitzherbert, _Natura brevium_, 269; 2 Hen. V. st. 1, c. 7).
+The "capital" punishment was generally (always in England) by burning.
+Burning was an English punishment for some secular offences.
+
+The Concordat with Francis I. by which the pope gave up the right of
+hearing appeals from France was not many years before the legislation of
+Henry VIII. in England. Both monarchs proceeded on the same lines; but
+Francis I. got the pope's consent: Henry VIII. acted _in invitum_, and
+in time went rather further.
+
+
+  Ecclesiastical jurisdiction in England.
+
+The Statute of Appeals (24 Hen. VIII. c. 12) takes away appeals to Rome
+in causes testamentary and matrimonial and in regard to right of tithes,
+oblations and obventions. A final appeal is given to the archbishop of
+the particular province; but in causes touching the king a final appeal
+is given to the Upper House of Convocation of the province. The statute
+is aimed at appeals; but the words used in it concerning "citations and
+all other processes" are wide enough to take away also the "original"
+jurisdiction of the pope. No appeal was yet given to the crown.
+Canterbury, York, Armagh, Dublin, Cashel and Tuam are put in the place
+of Rome. The English and Irish provinces are treated as self-contained.
+All ends there.
+
+The "Act of Submission of the Clergy" (25 Hen. VIII. c. 19) took away
+_all_ appeals to Rome and gave a further appeal, "for lack of justice,"
+from the several courts of the archbishops to the king in chancery.
+Thence a commission was to issue to persons named therein to determine
+the appeal definitely. This was copied from the then existent practice
+in admiralty appeals and was the origin of the so-called court of
+delegates. It is a moot question whether this statute took away the
+appeal to the Upper Houses of the various convocations in causes wherein
+the king was concerned (see _Gorham_ v. _Bishop of Exeter_, 15 Q.B. 52;
+_Ex parte Bishop of Exeter_, 10 C.B. 102; _Re Gorham_ v. _Bishop of
+Exeter_, 5 Exch. 630). 37 Hen. VIII. c. 17 provided that married laymen
+might be judges of the courts Christian if they were doctors of civil
+law, created in any university. This qualification even was considered
+unnecessary in Charles I.'s time (_Cro. Car._ 258). Canon 127 of 1603
+provided that the judges must be learned in the civil and ecclesiastical
+laws and at least masters of arts or bachelors of laws. Canon Law as a
+study had been practically prohibited at the universities since 1536
+(Merriman, _Thomas Cromwell_, i. 142-143; _Cal. State Papers_, vol. ix.
+p. xxix. 117; Owen, _Institutes of Canon Law_, viii.). The substitution
+of "civilians," rather than common lawyers, for canonists (civilians,
+hitherto, not an important body in England) had important consequences
+(see Maitland, op. cit. 92 et seq.).
+
+Henry VIII. had exercised his jurisdiction as Supreme Head through a
+vicar-general. Edward VI. exercised original jurisdiction in spiritual
+causes by delegated commissions (see Archdeacon Hale, _Precedents in
+Criminal Cases_, p. xlviii.). Unless the king was to be regarded as an
+ecclesiastical person, they were not properly ecclesiastical courts;
+although spiritual persons might sit in them, for they sat only as royal
+commissioners. The same point has been taken by large bodies of clergy
+and laity in regard to the court of final appeal created by 25 Hen.
+VIII. c. 19 and its present successor the judicial committee of Privy
+Council (_infra: Rep. Com. Ecc. Discipline_, pp. 9, 94 et seq.). At any
+rate the "original" jurisdiction claimed for the monarch personally and
+his delegates, under Henry VIII. and Edward VI., has not permanently
+remained. In theory, Hooker's contentions have been conceded that "kings
+cannot in their own proper persons decide questions about matters of
+faith and Christian religion" and that "they have not ordinary spiritual
+power" (_Ecc. Pol._ vii. 8, 1, 6; cf. _XXXIX. Articles_, Art. 37).
+
+Under Henry VIII. a system began of making certain crimes, which
+previously had been only of spiritual cognizance, felonies (25 Hen.
+VIII. c. 6), excluding thereby spiritual jurisdiction (Stephen, _Hist.
+Crim. Law_, ii. 429). Bigamy (in its modern sense) was thus made felony
+(1 Jac. I. c. 11). In this reign and the next, temporal courts were
+sometimes given jurisdiction over purely spiritual offences. A trace of
+this remains in 1 Edw. VI. c. 1 (still on the statute book; Stephen,
+_Hist. Crim. Law_, ii. 439). Other traces occur in the Acts of
+Uniformity, which make offences of depraving the Book of Common Prayer
+triable at Assizes (between 23 Eliz. c. 1 and 7 & 8 Vict. c. 102--also
+at Sessions) as well as in the courts Christian.
+
+During Edward VI.'s time the courts Christian seem practically to have
+ceased to exercise criminal jurisdiction (Hale, _Precedents in Criminal
+Cases_, p. xlix.). But they sat again for this purpose under Mary and
+Elizabeth and (save between 1640 and 1661) continued regular criminal
+sessions till towards the end of the 17th century as continuously and
+constantly as the king's courts (op. cit.).
+
+The "ordinary" ecclesiastical tribunals of the later middle ages still
+subsist in England, at least as regards the laity. This is hardly the
+case elsewhere in the Western Church, though some exceptions are noted
+below. Nevertheless, their exercise of criminal jurisdiction over the
+laity is now in practice suspended; although in law it subsists (see
+Stephen, _Hist. Crim. Law_; _Ray_ v. _Sherwood_, 1 Curt. R. 193; 1 Moore
+P.C.R. 363; the observations of Kelly, C.B., in _Mordaunt_ v.
+_Moncrieffe_, L.R. 2 Sc. & Div. 381, and of Lord Coleridge in _Martin_
+v. _Mackonochie_, L.R. 4 Q.B.D. 770, and, on the other hand, of Lord
+Penzance in _Phillimore_ v. _Machon_, L.R. 1 P.D. 480). Theoretically
+still, in cases of sexual immorality, penance may be imposed. Monitions
+to amend may be decreed and be enforced by _significavit_ and writ _de
+contumace capiendo_, or by excommunication with imprisonment not to
+exceed six months (53 Geo. III. c. 127). The tribunals thus subsisting
+are the courts of the bishop and archbishop, the latter sometimes called
+the court of appeal of the province. Peculiar jurisdictions have been
+gradually taken away under the operation of the acts establishing the
+ecclesiastical commissioners. The appeal given to delegates appointed by
+the crown has been transferred, first by 2 & 3 Will. IV. c. 92 to the
+privy council, and then by 3 & 4 Will. IV. c. 41 to the judicial
+committee of the privy council. Bishops may now be summoned as assessors
+by 39 & 40 Vict. c. 59.
+
+There was in the time of Elizabeth, James I. and Charles I. a "Court of
+High Commission" with jurisdiction over laity and clergy, based on 1
+Eliz. c. i. s. 15, which was reckoned as an ecclesiastical judicature (5
+R. 1, _Cawdrey's case_) concurrent with the ordinary court Christian. It
+was created by virtue of the royal supremacy, and was taken away by 16
+Car. I. c. 11. As to its history see Stephen, _Hist. Crim. Law_, ii.
+414-428.
+
+In regard to clerical offences, 3 & 4 Vict. c. 86 (the "Church
+Discipline Act") creates new tribunals; and first a commission of
+inquiry appointed by the bishop of five persons, of whom the
+vicar-general, or an archdeacon, or a rural dean of the diocese must be
+one. If they report a _prima facie_ case, the bishop may (with the
+consent of parties) proceed to sentence. In the absence of such
+consent, the bishop may hear the cause with three assessors, of whom one
+shall be a barrister of seven years' standing and another the dean of
+the cathedral, or one of the archdeacons, or the chancellor. This court
+is called the "consistory" court, but is not the old consistory. Both
+these tribunals are new. But the bishop may instead send the cause, in
+first instance, to the old provincial court, to which appeal lies, if it
+be not so sent.
+
+The Public Worship Regulation Act (37 & 38 Vict. c. 85) gave criminal
+jurisdiction over beneficed clerks (concurrent with that of the tribunal
+under 3 & 4 Vict. c. 86) to the judge under the act in matters of the
+fabric, ornaments, furniture and decorations of churches, and the
+conduct of divine service, rites and ceremonies. The "judge" under the
+act is to be a barrister of ten years' standing, or an ex-judge of a
+superior secular court, appointed by the archbishops of Canterbury and
+York, with the approval of the crown, or, if they fail to appoint, by
+the crown. Proceedings under this act are to be deemed to be taken in
+the appropriate ancient ecclesiastical courts (_Green_ v. _Lord
+Penzance_, 6 A. C. 657). The judge under this act became (upon vacancies
+occurring) _ex officio_ official principal of the arches court of
+Canterbury and of the chancery court of York. This provision caused
+grave doubts to be entertained as to the canonical position of this
+statutory official principal.
+
+Finally, the Clergy Discipline Act 1892 (55 & 56 Vict. c. 32) creates
+yet a new court of first instance for the trial of clerical offences
+against morality in the shape of a consistory court, which is not the
+old court of that name, but is to comprehend the chancellor and five
+assessors (three clergymen and two laymen chosen from a prescribed
+list), with equal power with the chancellor on questions of fact. In
+many instances the conviction of a temporal court is made conclusive on
+the bishop without further trial. In regard to moral offences,
+jurisdiction under this act is exclusive. But it only applies to clerks
+holding preferment. Under all these three acts there is a final appeal
+to the judicial committee of the privy council.
+
+None of these acts applies to the trial of bishops, who are left to the
+old jurisdictions, or whatever may be held to be the old jurisdictions
+(with that of the Roman See eliminated). As to suffragan bishops in the
+province of Canterbury, see _Read_ v. _Bishop of Lincoln_, 13 P.D. 221,
+14 P.D. 88. (On general questions see Phillimore, _Ecc. Law_, 65, 73.)
+Despite the bishop of Lincoln's case, the law is in some uncertainty.
+
+Dilapidations are now not made matters of suit before the court, but of
+administrative action by the bishop.
+
+The subject matter of ecclesiastical jurisdiction has been gradually
+reduced in England, &c., by various causes. (1) The taking away of all
+matrimonial, testamentary and _ab intestate_ jurisdiction by 20 & 21
+Vict. c. 77 (testamentary, &c., England), c. 79 (testamentary, &c.,
+Ireland), c. 85 (matrimonial, England); 33 & 34 Vict. c. 110
+(matrimonial, Ireland). Matrimonial jurisdiction was taken from the
+bishop of Sodor and Man in 1884. (2) Since 6 & 7 Will. IV. c. 71, tithe
+has become, except in a few rare cases, tithe rent charge, and its
+recovery has been entirely an operation of secular law. Most kinds of
+offerings are now recoverable in secular courts. (3) Administration of
+pious gifts has passed to the court of chancery. (4) The enforcement of
+contractual promises has long been abandoned by the courts Christian
+themselves. (5) Church rates can no longer be enforced by suit (31 & 32
+Vict. c. 109). (6) _Defamation_ was taken away in England by 18 & 19
+Vict. c. 41, and in Ireland by 23 & 24 Vict. c. 32. (7) Laymen can no
+longer be tried in the spiritual courts for offences against clerks. (8)
+The jurisdiction for "brawling" in church, &c., is taken away by 23 & 24
+Vict. c. 32 in the case of the laity. In the case of persons in holy
+orders there is a concurrent jurisdiction of the two tribunals
+(_Valancy_ v. _Fletcher_, 1897, 1 Q.B. 265). This was an offence very
+frequently prosecuted in the courts Christian (see A.J. Stephens,
+_Ecclesiastical Statutes_, i. 336).
+
+The existing ecclesiastical jurisdiction in England is therefore now
+confined to the following points. (1) Discipline of the clergy. (2)
+Discipline of the laity in respect of sexual offences as already
+stated. (3) Control of lay office-bearers, church-wardens, sidesmen,
+organists, parish clerks, sextons. (4) Protection of the fabrics of
+churches, of churchyards, ornaments, fittings, &c., sanctioning by
+licence or faculty any additions or alterations, and preventing or
+punishing unauthorized dealings by proceedings on the criminal side of
+the courts. (5) Claims by individuals to particular seats in church or
+special places of sepulture. (6) Rare cases of personal or special
+tithes, offerings or pensions claimed by incumbents of benefices. In the
+Isle of Man and the Channel Islands courts Christian have now
+jurisdiction substantially as in England. In Jersey and in Guernsey
+there are courts of first instance with appeal to the bishop of
+Winchester. Ecclesiastical jurisdiction in Ireland was as in England
+till the Irish Church was disestablished in 1869 by 32 & 33 Vict. c. 42.
+
+
+  Ecclesiastical jurisdiction in non-established churches.
+
+The position of a disestablished or an unestablished Church is
+comparatively modern, and has given rise to new jural conceptions. These
+Churches are _collegia licita_ and come within the liberty of
+association so freely conceded in modern times. The relations of their
+bishops, priests or other ministers and lay office-bearers _inter se_
+and to their lay folk depend upon contract; and these contracts will be
+enforced by the ordinary courts of law. A consensual ecclesiastical
+jurisdiction is thus created, which has to this extent temporal
+sanction. _In foro conscientiae_ spiritual censures canonically imposed
+are as binding and ecclesiastical jurisdiction is as powerful as ever.
+
+Into the British-settled colonies no bishops were sent till 1787; and
+consequently there were no regular courts Christian. The bishop of
+London was treated as the diocesan bishop of the colonists in North
+America; and in order to provide for testamentary and matrimonial
+jurisdiction it was usual in the letters patent appointing the governor
+of a colony to name him ordinary. In New York state there is still a
+court called the surrogates court, surrogate being the regular name for
+a deputy ecclesiastical judge. In Lower Canada, by treaty, the Roman
+Catholic Church remained established.
+
+Throughout the United States, whatever may have been the position in
+some of them before their independence, the Church has now no position
+recognized by the State, but is just a body of believers whose relations
+are governed by contract and with whom ecclesiastical jurisdiction is
+consensual.
+
+The position is the same now through all the British colonies (except,
+as already mentioned, Lower Canada or Quebec). From 1787 onwards,
+colonial bishops and metropolitans were appointed by letters patent
+which purported to give them jurisdiction for disciplinary purposes. But
+a series of cases, of which the most remarkable was that _Re the Bishop
+of Natal_ (3 Moore P.C. N.S. A.D. 1864), decided that in colonies
+possessing self-governing legislatures such letters patent were of no
+value; and soon after the crown ceased to issue them, even for crown
+colonies.
+
+In India the metropolitan of Calcutta and the bishops of Madras and
+Bombay have some very limited jurisdiction which is conferred by letters
+patent under the authority of the statutes 53 Geo. III. c. 155 and 3 & 4
+Will. IV. c. 85. But the other Indian bishops have no position
+recognized by the State and no jurisdiction, except consensual.
+
+
+  Ecclesiastical jurisdiction in Scotland.
+
+The Church had the same jurisdiction in Scotland, and exercised it
+through similar courts to those which she had in England and France,
+till about 1570. As late as 1566 Archbishop Hamilton of Glasgow, upon
+his appointment, had restitution of his jurisdiction in the probate of
+testaments and other matters (Keith, _History of the Scottish Bishops_,
+Edinburgh, 1824, p. 38). There was an interval of uncertainty, with at
+any rate titular bishops, till 1592. Then parliament enacted a new
+system of Church courts which, though to some extent in its turn
+superseded by the revival of episcopacy under James VI., was revived or
+ratified by the act of 1690, c. 7, and stands to this day. It is a
+Presbyterian system, and the Scottish Episcopal Church is a
+disestablished and voluntary body since 1690.
+
+The Presbyterian courts thus created are arranged in ascending order:--
+
+(a) _Kirk Session_ consists of the minister of the parish and the
+"ruling elders" (who are elected by the session). It has cognizance of
+scandalous offences by laymen and punishes them by deprivation of
+religious privileges. It does not judge ministers (Brodie-Innes,
+_Comparative Principles of the Laws of England and Scotland_, 1903, p.
+144).
+
+(b) The _Presbytery_ has jurisdiction, partly appellate and partly
+original, over a number of parishes. There are now eighty-four
+presbyteries. These courts consist of every parochial minister or
+professor of divinity of any university within the limits, and of an
+elder commissioned from every kirk session. A minister is elected to
+preside as moderator. These courts judge ministers in first instance for
+scandalous conduct. As civil courts they judge in first instance all
+questions connected with glebes and the erection and repair of churches
+and manses. They regulate matters concerning public worship and
+ordinances, and have appellate jurisdiction from the kirk session.
+
+(c) The _Provincial Synod_ consists of a union of three or more
+presbyteries with the same members. There are now sixteen. They meet
+twice a year to hear appeals from presbyteries. No appeal can go direct
+to the General Assembly, _omisso medio_, unless the presbytery have so
+expressly directed, or unless there be no meeting of synod after the
+decision of the presbytery before the meeting of General Assembly.
+
+(d) The _General Assembly_ is the supreme ecclesiastical court of this
+system. It meets annually. The king's "lord high commissioner" attends
+the sittings; but does not intervene or take part in the court's
+decisions. The court consists of ministers and elders, elected from the
+presbyteries in specified proportions, and of commissioners from the
+four universities, the city of Edinburgh and the royal burghs. The
+Presbyterian Church in India sends one minister and one elder. The whole
+Assembly consists of 371 ministers and 333 elders. The jurisdiction is
+entirely appellate. The Assembly appoints a commission to exercise some
+of its functions during the intervals of its session. To this commission
+may be referred the cognizance of particular matters.
+
+Questions of _patronage_ now (by 37 & 38 Vict. c. 82) belong to the
+Church courts; but not questions of _lapse_ or _stipend_. Seats, seat
+rents, pews, the union and disjunction of parishes and formation of
+district parishes are of secular jurisdiction. Questions of tithes (or
+"teinds") and ministers' stipends were referred to commissioners by acts
+of the Scots parliaments beginning in 1607. The commissioners of teinds
+became a species of ecclesiastical court. By Scots act of 1707, c. 9,
+their powers were transferred to the judges of the court of session, who
+now constitute a "teind court" (Brodie-Innes, op. cit. pp. 138, 139).
+Matrimonial matters and those relating to wills and succession (called
+in Scotland "consistorial" causes) were in 1563 taken from the old
+bishops' courts and given to "commissaries" appointed by the crown with
+an appeal to the court of session, which by act 1609, c. 6, was declared
+the king's great consistory. They have remained matters of secular
+jurisdiction.
+
+The Scots ecclesiastical courts are entitled to the assistance of the
+secular courts to carry out their jurisdiction by "due assistance."
+Within the limits of their jurisdiction they are supreme. But if a court
+go outside its jurisdiction, or refuse to exercise powers conferred on
+it by law, the civil court may "reduce" (i.e. set aside) the sentence
+and award damages to the party aggrieved.
+
+
+  Protestant continental European states.
+
+With the Reformation in the 16th century, Church courts properly
+speaking disappeared from the non-episcopal religious communities which
+were established in Holland, in the Protestant states of Switzerland and
+of Germany, and in the then non-episcopal countries of Denmark and
+Norway.
+
+Discipline over ministers and other office-bearers was exercised by
+administrative methods in the form of trials before consistories or
+synods. To this extent ecclesiastical jurisdiction is still exercised in
+these countries. Consistories and synods have exercised discipline of a
+penitential kind over their lay members; but in later times their
+censures have generally ceased to carry temporal consequences.
+Ecclesiastical jurisdiction on the civil side for the trial of causes
+soon disappeared. Heresy has been treated as a crime to be tried in and
+punished by the ordinary courts of the country, as in the cases of
+Servetus (q.v.) and Grotius (q.v.).
+
+For the episcopal churches of Sweden and Finland the first constitution
+or "Church order" was formed in 1571. It provided for the visitation of
+the clergy by the bishop, and for the power of the clergy to exclude
+their lay folk from the Holy Communion, subject to appeal to the bishop.
+Both minor and major excommunication had been in use, and for a long
+time public penance was required. The procedure underwent great
+modification in 1686; but public penance was not taken away till 1855,
+and then confession to and absolution by the priest in the presence of
+witnesses was still required. Civil jurisdiction in causes appears to
+have been given up early (Cornelius, _Svenska Kirkaus Historia_, Upsala,
+1875, pp. 146, 186, 189, 285).
+
+
+  Roman Catholic countries.
+
+Over the rest of western continental Europe and in the colonies of
+Spain, Portugal and France, ecclesiastical jurisdiction remained
+generally in the state which we have already described till near the end
+of the 18th century. The council of Trent took away the jurisdiction of
+archdeacons in marriage questions. The testamentary jurisdiction
+disappeared (as already stated) in France. Disputed cases of contract
+were more often tried in the secular courts. Recourse to the secular
+prince by way of _appel comme d'abus_, or otherwise, became more
+frequent and met with greater encouragement. Kings began to insist upon
+trying ecclesiastics for treason or other political crimes in secular
+courts. So under the advice of his minister (the marquis of Pombal),
+King Joseph of Portugal in 1759-1760 claimed that the pope should give
+him permission to try in all cases clerics accused of treason, and was
+not content with the limited permission given to try and execute, if
+guilty, the Jesuits then accused of conspiring his death (_Life of
+Pombal_, by Count da Carnota, 1871, pp. 128, 141). But there was no
+sudden change in the position of the courts Christian till the French
+Revolution.
+
+In France a law of the Revolution (September 1790) purported to suppress
+all ecclesiastical jurisdictions. On the re-establishing of the Catholic
+religion on the basis of the new Concordat, promulgated 18 Germinal,
+year X. (April 8, 1802), no express provision was made for
+ecclesiastical jurisdictions; but several bishops did create new
+ecclesiastical tribunals, "officialities" (Migne, _Dict. de droit
+canon._, s.v.). The government in some cases recognized these tribunals
+as capable of judging ecclesiastical causes (Migne, _ubi sup._). In 1810
+the diocesan official of Paris entertained the cause between Napoleon
+and Josephine, and pronounced a decree of nullity (Migne, _ubi sup._
+s.v. "Causes"). Such litigation as still continued before the spiritual
+forum was, however, confined (save in the case of the matrimonial
+questions of princes) to the professional conduct of the clergy.
+
+Such neighbouring countries as were conquered by France or
+revolutionized after her pattern took the same course of suppressing
+their ecclesiastical jurisdictions. After 1814, some of these
+jurisdictions were revived. But the matter is now determined for all
+countries which have adopted codes, whether after the pattern of the
+Code Napoleon or otherwise. These countries have created a hierarchy of
+temporal courts competent to deal with every matter of which law takes
+cognizance, and a penal code which embraces and deals with all crimes or
+delicts which the state recognizes as offences. Hence, even in countries
+where the Roman Church is established, such as Belgium, Italy, the
+Catholic states of Germany and cantons of Switzerland, most of the Latin
+republics of America, and the province of Quebec, and _a fortiori_ where
+this Church is not established, there is now no discipline over the
+laity, except penitential, and no jurisdiction exercised in civil suits,
+except possibly the matrimonial questions of princes (of which there was
+an example in the case of the reigning prince of Monaco). In Spain
+causes of nullity and divorce _a thoro_, in Portugal causes of nullity
+between Catholics, are still for the court Christian. In Peru, the old
+ecclesiastical matrimonial jurisdiction substantially remains (Lehr, _Le
+Mariage dans les principaux pays_, 1899, arts. 362, 797, 772, 781).
+Otherwise these three countries are Code countries. In Austria, the
+ancient ecclesiastical jurisdiction was taken away by various acts of
+legislation from 1781 to 1856; even voluntary jurisdiction as to
+dispensations. The Concordat of 1856 and consequent legislation restored
+matrimonial jurisdiction to the courts Christian over marriages between
+Roman Catholics. In 1868 this was taken away. The Austrian bishops,
+however, maintain their tribunals for spiritual purposes, and insist
+that such things as divorce _a vinculo_ must be granted by their
+authority (Aichner, _Compendium juris ecclesiastici_, pp. 551-553).
+
+By consent and submission of her members, the Roman Church decides _in
+foro conscientiae_ questions of marriage, betrothal and legitimacy
+everywhere; but no temporal consequences follow except in Spain,
+Portugal and Peru.
+
+The position in France was the same as that in Belgium, Italy, &c., till
+1906, when the Church ceased to be established. The only Latin countries
+in which conflict has not arisen appear to be the principality of
+Andorra and the republic of San Marino (Giron y Areas, _Situacion
+juridica de la Iglesia Catolica_, Madrid, 1905, p. 173 et seq.).
+
+Even as to the discipline of the Roman clergy it is only in certain
+limited cases that one can speak of ecclesiastical jurisdiction. Bishops
+and beneficed incumbents (_cures_) must be regularly tried; and where
+the Church is established the canonical courts are recognized. But the
+majority of parishes are served by mere _desservants_ or _vicaires_, who
+have no rights and can be recalled and dismissed by mere administrative
+order without trial (Migne, _ubi sup._ s.v. "Inamovibilite,"
+"Desservants").
+
+The Napoleonic legislation re-established the _appel comme d'abus_
+("_Articles organiques_," art. 6). The recourse was now to the council
+of state (see Migne, _ubi supra_, "Officialite"). But the revocation of
+a _desservant_, and the forbidding him the execution of his ministry in
+the diocese, was not a case in which the council of state would
+interfere (Migne, _ubi sup._ "Appel comme d'abus," "Conseil d'etat").
+
+
+  Jurisdiction in Anglican communion.
+
+In those provinces of the Anglican communion where the Church is not
+established by the state, the tendency is not to attempt any external
+discipline over the laity; but on the other hand to exercise consensual
+jurisdiction over the clergy and office-bearers through courts nearly
+modelled on the old canonical patterns.
+
+
+  Modern jurisdiction of Church of Rome.
+
+In the Roman communion, on the other hand, both where the Church is
+established and where it is not, the tendency is to reduce the status of
+_cure_ to that of _desservant_, and to deal with all members of the
+priestly or lower orders by administrative methods. This practice
+obtains in all missionary countries, e.g. Ireland and also in Belgium
+(S.B. Smith, _Elements of Ecclesiastical Law_, New York, i. 197 et seq.;
+p. 403 et seq.; Tauber, _Manuale juris canonici_, Sabariae, 1904, p.
+277). In the United States, the 3rd plenary council of Baltimore in 1884
+provided that one rector out of ten should be irremovable (Smith, op.
+cit. i. 197, 419). In England there are few Roman "benefices" (E.
+Taunton, _Law of the Church_, London, 1906, s.v. "Benefice"). A
+_desservant_ has an informal appeal, by way of recourse, to the
+metropolitan and ultimately to the pope (Smith, op. cit. p. 201). The
+bishop's "official" is now universally called his vicar-general (except
+in France, where sometimes an _official_ is appointed _eo nomine_), and
+generally exercises both voluntary and contentious jurisdiction (op.
+cit. i. 377). As of old, he must be at least tonsured and without a wife
+living. At the Vatican Council, a desire was expressed that he should be
+a priest (ib.). He should be a doctor in theology or a licentiate in
+canon law (ib. p. 378). Whether a bishop is bound to appoint a
+vicar-general is still disputed (ib. p. 380; cf. _supra_; _contra_,
+Bouix, _Inst. Juris Canon. De Judic._ i. 405). In 1831 the pope enacted
+that in all the dioceses of the then Pontifical States, the court of
+first instance for the criminal causes of ecclesiastics should consist
+of the ordinary and four other judges. In the diocese of Rome, the
+court of the cardinal vicar-general consists of such vicar-general and
+four other prelates (Smith, _ubi supra_). In the Roman communion in
+England and the United States, there are commissions of investigation
+appointed to hear in first instance the criminal causes of clerks. They
+consist of five, or at least three, priests nominated by the bishop in
+and with the advice of the diocesan synod. In the United States, since
+1884, the bishop presides on these commissions. They report their
+opinions to the bishop, who passes final sentence (ib. ii. 129-131).
+
+"Exemptions" now include all the regular religious orders, i.e. those
+orders which have solemn vows. Over the members of these orders their
+superiors have jurisdiction and not the bishop. Otherwise if they live
+out of their monastery, or even within that enclosure so notoriously
+offend as to cause scandal. In the first case, they may be punished by
+the ordinary of the place, acting as delegate of the pope without
+special appointment (_Conc. Trid. Sess._ vi. c. 3). In the second case,
+the bishop may require the superior to punish within a certain time and
+to certify the punishment to him; in default he himself may punish
+(_Conc. Trid. Sess._ xxv. c. 14, cf. Smith, op. cit. i. 204-206). So,
+regulars having cure of souls are subject to the jurisdiction of the
+bishop in matters pertaining thereto (ib. p. 206). The exemption of
+regular religious orders may be extended to religious societies without
+solemn vows by special concession of the pope, as in the case of the
+Passionists and Redemptorists (ib. p. 205; Sanguineti, _Juris ecc.
+inst._, Rome, 1800, pp. 393, 394).
+
+Appeal lies, in nearly all cases, to the metropolitan (Smith, op. cit.
+pp. 219-223). Metropolitans usually now have a metropolitan tribunal
+distinct from their diocesan court (ib. ii. 141), but constructed on the
+same lines, with the metropolitan as judge and his vicar-general as
+vice-judge. In some "missionary" dioceses, the metropolitan, _qua_
+metropolitan, has a separate commission of investigation, to try the
+criminal causes of clerks, sentence being passed by himself or his
+vicar-general (ib. p. 142).
+
+The next step in the hierarchy, that of "primates" (_supra_), has "in
+the present state of the Church" ceased to exist for our purpose
+(Sanguineti, op. cit. p. 334), as a result of Tridentine legislation.
+The only appellate jurisdiction from the metropolitans is the Roman See.
+To it also lies a direct appeal from the court of first instance,
+_omisso medio_ (Smith, op. cit. i. 224). The pope's immediate and
+original jurisdiction in every diocese is now expressly affirmed by the
+Vatican Council (ib. p. 239). That original jurisdiction he reserves
+exclusively to himself in _causis majoribus_ (ib. pp. 249-250). These
+are (1) causes relating to elections, translations and deprivations of,
+and criminal prosecutions against, bishops, and (2) the matrimonial
+cases of princes (Taunton, op. cit. s.v. "Cause").
+
+
+  Eastern Church.
+
+In the Eastern Church, the early system of ecclesiastical judicature
+long continued. But a sacred character was ascribed to the emperors.
+They are "anointed lords like the bishops" (Balsamon, in _Conc. Ancyr.
+Can._ xii., representing the view of the 12th and 13th centuries).
+Bishops were often deposed by administrative order of the emperor;
+synods being expected afterwards to confirm, or rather accept, such
+order. The germ of this dealing with a _major causa_ may be found in the
+practice of the Arian emperors in the 4th century. The cause of Ignatius
+and Photius was dealt with in the 9th century by various synods; those
+in the East agreeing with the emperor's view for the time being, while
+those in the West acted with the pope. (The details are in Mansi, _Conc.
+in locis_, and in Hefele, _Conc. in locis_, more briefly. They are
+summarized in Landon, _Manual of Councils_, s.v. "Constantinople,"
+"Rome," and in E.S. Foulkes, _Manual of Ecclesiastical History_, s.v.
+"Century IX.") Since these transactions patriarchs have been deposed by
+the Byzantine emperors; and the Turkish sultans since the 15th century
+have assumed to exercise the same prerogative.
+
+The spiritual courts in the East have permanently acquired jurisdiction
+in the matrimonial causes of baptized persons; the Mahommedan
+governments allowing to Christians a personal law of their own. The
+patriarch of Constantinople is enabled to exercise an extensive
+criminal jurisdiction over Christians (Neale, _Hist. of the Eastern
+Church_, i. 30, 31).
+
+The empire of Russia has in the matter of ecclesiastical jurisdiction
+partly developed into other forms, partly systematized 4th century and
+later Byzantine rules. The provincial system does not exist; or it may
+be said that all Russia is one province. An exception should be made in
+the case of Georgia, which is governed by an "exarch," with three
+suffragans under him. In the remainder of the empire the titles of
+metropolitan, save in the case of the metropolitan of all Russia, and of
+archbishop, were and are purely honorary, and their holders have merely
+a diocesan jurisdiction (see Mouravieff, _History of the Russian
+Church_, translated Blackmore, 1842, translator's notes at pp. 370, 390,
+416 et seq.). So in Egypt the bishop or "pope" (afterwards patriarch) of
+Alexandria was the only true metropolitan (Neale, _History of the
+Eastern Church_, Gen. Introd. vol. i. p. 111). The metropolitan of
+Russia from the time of the conversion (A.D. 988) settled at Kiev, and
+his province was part of the patriarchate of Constantinople, and appeals
+lay to Constantinople. Many such appeals were taken, notably in the case
+of Leon, bishop of Rostov (Mouravieff, op. cit. p. 38). The
+metropolitical see was for a short time transferred to Vladimir and then
+finally to Moscow (Mouravieff, chs. iv., v.). After the taking of
+Constantinople in 1452, the Russian metropolitans were always chosen and
+consecrated in Russia, appeals ceased, and Moscow became _de facto_
+autocephalous (Joyce, ubi sup. p. 379; Mouravieff, op. cit. p. 126). The
+tsar Theodore in 1587 exercised the power of the Byzantine emperors by
+deposing the metropolitan, Dionysius Grammaticus (Mouravieff, p. 125).
+In 1587 the see of Moscow was raised to patriarchal rank with the
+consent of Constantinople, and the subsequent concurrence of Alexandria,
+Antioch and Jerusalem (ib. c. vi.). Moscow became the final court, in
+theory, as it had long been in practice. Certain religious houses,
+however, had their own final tribunals and were "peculiars," exempt from
+any diocesan or patriarchal jurisdiction for at least all causes
+relating to Church property (ib. p. 131).
+
+The subject matter of ecclesiastical jurisdiction in Russia during the
+whole patriarchal period included matrimonial and testamentary causes,
+inheritance and sacrilege, and many questions concerning the Church
+domains and Church property, as well as spiritual offences of clergy and
+laity (ib.). The bishops had consistorial courts; the patriarchs,
+chanceries and consistories (ib.). Bishops were judged in synod (see,
+e.g. the case of the archbishop of Polotsk in 1622, ib. p. 179) and only
+lawfully judged in synod (ib. p. 215).
+
+Clerks and the dependants of the metropolitan (afterwards the patriarch)
+appear to have been immune from secular jurisdiction, except in the case
+of crimes against life, from the time of Ivan the Terrible (ib. pp.
+180-181). The tsar Michael, in the earlier 17th century, confirmed these
+immunities in the case of the clergy of the patriarch's own diocese, but
+provided that in country places belonging to his diocese, monasteries,
+churches and lands should be judged in secular matters by the Court of
+the Great Palace, theoretically held before the tsar himself (ib. p.
+181). This tsar limited the "peculiar" monasteries to three, and gave
+the patriarch jurisdiction over them (ib.). The next tsar, Alexis,
+however, by his code instituted a "Monastery Court," which was a secular
+tribunal composed of laymen, to judge in civil suits against spiritual
+persons, and in matters arising out of their manors and properties (ib.
+p. 193). This court was not in operation during the time when the
+patriarch Nikon was also in effect first minister; but upon his decline
+exercised its full jurisdiction (ib. p. 216). Nikon was himself tried
+for abdicating his see, causing disorder in the realm, oppression and
+violence, first before a synod of Moscow composed of his suffragans and
+some Greek bishops, and afterwards before another synod in which sat the
+patriarchs of Alexandria and Antioch, the metropolitans of Servia and
+Georgia, the archbishops of Sinai and Wallachia, and the metropolitans
+of Nice, Amasis, Iconium, Trebizond, Varna and Scio, besides the Russian
+bishops. This synod in 1667 deposed Nikon, degraded him from holy
+orders, and sentenced him to perpetual penance in a monastery (ib. pp.
+220-232). The next tsar, Theodore, suppressed the secular "monastery
+court," and directed that all suits against spiritual persons should
+proceed only in the patriarchal "court of requests" (ib. p. 264). There
+was, however, a species of _appel comme d'abus_. Causes could be evoked
+to the tsar himself, "when any partiality of the judges in any affair in
+which they themselves were interested was discovered" (ib.).
+
+The old system was swept away by Peter the Great, who settled
+ecclesiastical jurisdiction substantially on its present basis. The
+patriarchate was abolished and its jurisdiction transferred by a council
+at St Petersburg in 1721 to a Holy Governing Synod. The change was
+approved by the four patriarchs of the East in 1723 (ib. chs.
+xv.-xvii.). Peter permanently transferred to the secular _forum_ the
+testamentary jurisdiction and that concerning inheritance, as also
+questions of "sacrilege" (ib. p. 264). As the result of a long series of
+legislation, beginning with him and ending with Catherine II., all
+church property of every kind was transferred to secular administration,
+allowances, according to fixed scales, being made for ministers, monks
+and fabrics (op. cit. translator's appendix i. p. 413 et seq.). There
+remain to the spiritual courts in Russia the purely ecclesiastical
+discipline of clerks and laity and matrimonial causes.
+
+The court of first instance is the "consistorial court" of the bishop.
+This consists of a small body of ecclesiastics. Its decisions must be
+confirmed by the bishop (op. cit. translator's appendix ii. pp.
+422-423). In the more important causes, as divorce (i.e. _a vinculo_),
+it only gives a provisional decision, which is reported by the bishop,
+with his own opinion, for final judgment, to the Most Holy Governing
+Synod.
+
+The governing synod is the final court of appeal. It consists of a small
+number of bishops and priests nominated by the tsar, and is assisted by
+a "procurator," who is a layman, who explains to it the limits of its
+jurisdiction and serves as the medium of communication between it and
+the autocrat and secular authorities. It deals with the secular crimes
+of spiritual persons, if of importance and if not capital (these last
+being reserved for the secular forum), and with heresy and schism. It is
+the only court which can try bishops or decree divorce. The tsar
+formally confirms its judgments; but sometimes reduces penalties in the
+exercise of the prerogative of mercy (see Mouravieff, op. cit. ch. xvii.
+translator's app. ii.).
+
+The governing synod now sits at St Petersburg, but appoints delegated
+commissions, with a portion of its jurisdiction, in Moscow and Georgia.
+The latter commission is presided over by the "exarch" (_supra_).
+
+Since the War of Independence, the kingdom of Greece has been
+ecclesiastically organized after the model of Russia, as one
+autocephalous "province," separated from its old patriarchate of
+Constantinople, with an honorary metropolitan and honorary archbishops
+(Neale, op. cit. Gen. Introd. vol. i.). The Holy Synod possesses the
+metropolitical jurisdiction. It sits at Athens. The metropolitan of
+Athens is president, and there are four other members appointed by the
+government in annual rotation from the senior bishops. There is attached
+to it a government commissioner, with no vote, but affixing his
+signature to the synodical judgments (Joyce, op. cit. p. 35).
+
+The subject matter of the jurisdiction of Hellenic courts Christian
+seems to be confined to strictly spiritual discipline, mainly in regard
+to the professional misconduct of the clergy. Imprisonment may be
+inflicted in these last cases (ib.). All matrimonial causes are heard by
+the secular tribunals (Lehr, op. cit. sec. 587).
+
+The bishop's consistorial court, consisting of himself and four priests,
+has a limited jurisdiction in first instance. Such a court can only
+suspend for seven days unless with the sanction of the Holy Synod
+(Joyce, op. cit.).
+
+The Holy Synod can only inflict temporary suspension, or imprisonment
+for fifteen days, unless with the sanction of the King's ministry.
+Deprivation, or imprisonment for more than two months, requires the
+approval of the king (ib.). The king or the ministry do not, however,
+rehear the cause by way of appeal, but merely restrain severity of
+sentence (ib.).
+
+The Church of Cyprus has been autocephalous since at any rate the
+oecumenical synod of Ephesus in 431. The episcopate now consists of an
+archbishop and three suffragans (Hackett, _Orthodox Church in Cyprus_,
+1901, ch. v. _et passim_). The final court is the island synod, which
+consists of the archbishop, his suffragans and four dignified priests.
+It has original and exclusive cognizance of causes of deposition of
+bishops (op. cit. pp. 260, 262).
+
+Each bishop is assisted by at least two officers with judicial or
+quasi-judicial powers, the "archimandrite" who adjudicates upon causes
+of revenue and the archdeacon who adjudicates on questions between
+deacons (op. cit. pp. 272-273). The "exarch" of the archbishop, who is a
+dignitary but not a bishop, has a seat in the provincial synod.
+
+In the Balkan States, the system--inherited from Byzantine and Turkish
+times--of ecclesiastical jurisdictions prevails, except that they are
+now autocephalous, and independent of the patriarch of Constantinople.
+Matrimonial causes in Servia are of ecclesiastical cognizance (Lehr, op.
+cit. sect. 901).
+
+  AUTHORITIES.--St Augustine, _Epistles_; _Codex Theodosianus_, edited
+  by Th. Mommsen and P.M. Meyer (1905); _Code and Novells of Emperor
+  Justinian_, ed. J. Gothofredus (1665); T. Balsamon, "In Conc. Ancyr."
+  in the _Corpus juris canonici_ (1879-1881); "_Hostiensis_" _Super
+  Decretum_; W. Lyndwood, _Provinciale_ (Oxford, 1679); Sir A.
+  Fitzherbert, _Natura brevium_ (1534); Sir T. Ridley, _View of the
+  Civile and Ecclesiastical Law_ (1607); J. Ayliffe, _Parergon juris
+  ecclesiastici_ (1726); J. Godolphin, _Abridgement of the Laws
+  Ecclesiastical_ (London, 1687); E. Gibson, _Codex juris ecclesiastici_
+  (Oxford, 1761); D. Covarruvias, _Opera omnia_ (Antwerp, 1638); Jean
+  Hardouin, _Concilia_ (1715); J.D. Mansi, _Concilia_ (1759-1798); E.
+  Stillingfleet, _Ecclesiastical Jurisdiction_ (1704); L.S. le Nain de
+  Tillemont, _Memoires pour servir a l'histoire ecclesiastique_
+  (1701-1712); P.T. Durand de Maillane, _Dictionnaire du droit
+  canonique_ (1761); _Dictionnaire ecclesiastique et canonique_, par une
+  societe de religieux (Paris, 1765); Z.B. van Espen, _Jus
+  ecclesiasticum universum_ (Louvain, 1720), _De recursu ad Principem,
+  observationes in Concilium Lateranense iv._; L. Thomassin, _Vetus et
+  nova disciplina ecc._ (1705-1706); W. Beveridge, _Synodicon_ (Oxford,
+  1672); J.A.S. da Carnota, _Life of Pombal_ (1843); J.P. Migne,
+  _Dictionnaire de droit canon._ (Paris, 1844); R. Keith, _History of
+  the Scottish Bishops_ (Edinburgh, 1824); P.N. Vives y Cebria, _Usages
+  y demas derechos de Cataluna_ (1832); C.A. Cornelius, _Svenska Kyrkaus
+  Historia_ (Upsala, 1875); Mouravieff, _History of the Russian Church_
+  (trans. Blackmore, 1842); Ffoulkes, _Manual of Ecclesiastical History_
+  (1851); E.H. Landon, _Manual of Councils of the Church_ (1893); W.H.
+  Hale, _Precedents in Criminal Cases_ (London, 1847); E.B. Pusey,
+  _Councils of the Church_ (Oxford, 1857); C.J. von Hefele,
+  _Conciliengeschichte_ (Freiburg, 1855-1890); M. Gaudry, _Traite de la
+  legislation des cultes_ (Paris, 1854); W. Stubbs, _Select Charters_
+  (Oxford, 1895); A.W. Haddan and W. Stubbs, _Councils and
+  Ecclesiastical Documents_ (Oxford, 1869); A.J. Stephens,
+  _Ecclesiastical Statutes_ (1845); H.C. Rothery, _Return of Cases
+  before Delegates_ (1864); J.W. Joyce, _The Sword and the Keys_ (2nd
+  ed., 1881); _Report of Ecclesiastical Courts Commission_ (1888); P.
+  Fournier, _Les Officialites au moyen age_ (1880); S.B. Smith,
+  _Elements of Ecclesiastical Law_ (New York, 1889-1890); S. Sanguineti,
+  _Juris ecc. inst._ (Rome, 1890); J.F. Stephen, _History of the
+  Criminal Law of England_ (London, 1883); Pollock and Maitland,
+  _History of English Law before Edward I._ (1898); F.W. Maitland,
+  _Roman Canon Law in the Church of England_ (1898); R. Owen, _Canon
+  Law_ (1884); Sir R.J. Phillimore, _Ecclesiastical Law_ (2nd ed.,
+  1895); J.W. Brodie-Innes, _Comparative Principles of the Laws of
+  England and Scotland_ (1903); R.B. Merriman, _Life and Letters of
+  Thomas Cromwell_ (1902); S. Aichner, _Compendium juris ecclesiast._
+  (8th ed., Brixen, 1905, especially in regard to Austro-Hungarian
+  Empire); J. Hackett, _History of the Orthodox Church in Cyprus_
+  (1901); Tauber, _Manuale juris canonici_ (1906); E.L. Taunton, _Law of
+  the Church_ (London, 1906); _Report of Royal Commission on
+  Ecclesiastical Discipline_ (1906).     (W. G. F. P.)
+
+
+
+
+ECCLESIASTICAL LAW, in its broadest sense, the sum of the authoritative
+rules governing the Christian Church, whether in its internal polity or
+in its relations with the secular power. Since there are various
+churches, widely differing alike in their principles and practice, it
+follows that a like difference exists in their ecclesiastical law, which
+is the outcome of their corporate consciousness as modified by their
+several relations to the secular authority. At the outset a distinction
+must be made between churches which are "established" and those that are
+"free." The ecclesiastical laws of the latter are, like the rules of a
+private society or club, the concern of the members of the church only,
+and come under the purview of the state only in so far as they come in
+conflict with the secular law (e.g. polygamy among the Mormons, or
+violation of the trust-deeds under which the property of a church is
+held). In the case of "established" Churches, on the other hand,
+whatever the varying principle on which the system is based, or the
+difference in its practical application, the essential conditions are
+that the ecclesiastical law is also the law of the land, the decisions
+of the church courts being enforced by the civil power. This holds good
+both of the Roman Catholic Church, wherever this is recognized as the
+"state religion," of the Oriental Churches, whether closely identified
+with the state itself (as in Russia), or endowed with powers over
+particular nationalities within the state (as in the Ottoman empire),
+and of the various Protestant Churches established in Great Britain and
+on the continent of Europe.
+
+Writers on the theory of ecclesiastical law, moreover, draw a fundamental
+distinction between that of the Church of Rome and that of the Protestant
+national or territorial Churches. This distinction is due to the claim of
+the Roman Catholic Church to be the _only_ Church, her laws being thus of
+universal obligation; whereas the laws of the various established
+Protestant Churches are valid--at least so far as legal obligation is
+concerned--only within the limits of the countries in which they are
+established. The practical effects of this distinction have been, and
+still are, of enormous importance. The Roman Catholic Church, even when
+recognized as the state religion, is nowhere "established" in the sense
+of being identified with the state, but is rather an _imperium in
+imperio_ which negotiates on equal terms with the state, the results
+being embodied in concordats (q.v.) between the state and the pope as
+head of the Church. The concordats are of the nature of truces in the
+perennial conflict between the spiritual and secular powers, and imply in
+principle no surrender of the claims of the one to those of the other.
+Where the Roman Catholic Church is not recognized as a state religion, as
+in the United States or in the British Islands, she is in the position of
+a "free Church," her jurisdiction is only _in foro conscientiae_, and her
+ecclesiastical laws have no validity from the point of view of the state.
+On the other hand, the root principle of the ecclesiastical law of the
+established Protestant Churches is the rejection of alien jurisdiction
+and the assertion of the supremacy of the state. The theory underlying
+this may vary. The sovereign may be regarded, as in the case of the
+Russian emperor or of the English kings from the Reformation to the
+Revolution, as the vicar of God in all causes spiritual as well as
+temporal within his realm. As the first fervent belief in the divine
+right of kings faded, however, a new basis had to be discovered for a
+relation between the spiritual and temporal powers against which Rome had
+never ceased to protest. This was found in the so-called "collegial"
+theory of Church government (_Kollegialsystem_), which assumed a sort of
+tacit concordat between the state and the religious community, by which
+the latter vests in the former the right to exercise a certain part of
+the _jus in sacra_ properly inherent in the Church (see PUFENDORF,
+SAMUEL). This had great and lasting effects on the development of the
+theory of Protestant ecclesiastical law on the continent of Europe. In
+England, on the other hand, owing to the peculiar character of the
+Reformation there and of the Church that was its outcome, no theory of
+the ecclesiastical law is conceivable that would be satisfactory at once
+to lawyers and to all schools of opinion within the Church. This has been
+abundantly proved by the attitude of increasing opposition assumed by the
+clergy, under the influence of the Tractarian movement, towards the civil
+power in matters ecclesiastical, an attitude impossible to justify on any
+accepted theory of the Establishment (see below).
+
+Protestant ecclesiastical law, then, is distinguished from that of the
+Roman Catholic Church (1) by being more limited in its scope, (2) by
+having for its authoritative source, not the Church only or even mainly,
+but the Church in more or less complete union with or subordination to
+the State, the latter being considered, equally with the Church, as an
+organ of the will of God. The ecclesiastical law of the Church of Rome,
+on the other hand, whatever its origin, is now valid only in so far as
+it has the sanction of the authority of the Holy See. And here it must
+be noted that the "canon law" is not identical with the "ecclesiastical
+law" of the Roman Catholic Church. By the canon law is meant,
+substantially, the contents of the _Corpus juris canonici_, which have
+been largely superseded or added to by, e.g. the canons of the council
+of Trent and the Vatican decrees. The long projected codification of the
+whole of the ecclesiastical law of the Church of Rome, a work of
+gigantic labour, was not taken in hand until the pontificate of Pius X.
+(See also CANON LAW and ECCLESIASTICAL JURISDICTION.)
+
+The ecclesiastical law of England is in complete dependence upon the
+authority of the state. The Church of England cannot be said, from a
+legal point of view, to have a corporate existence or even a
+representative assembly. The Convocation of York and the Convocation of
+Canterbury are provincial assemblies possessing no legislative or
+judicial authority; even such purely ecclesiastical questions as may be
+formally commended to their attention by "letters of business" from the
+crown can only be finally settled by act of parliament. The
+ecclesiastical courts are for the most part officered by laymen, whose
+subordination to the archbishops and bishops is purely formal, and the
+final court of appeal is the Judicial Committee of the Privy Council. In
+like manner changes in the ecclesiastical law are made directly by
+parliament in the ordinary course of legislation, and in point of fact a
+very large portion of the existing ecclesiastical law consists of acts
+of parliament.
+
+The sources of the ecclesiastical law of England are thus described by
+Dr. Richard Burn (_The Ecclesiastical Law_, 9th ed., 1842):--"The
+ecclesiastical law of England is compounded of these four main
+ingredients--the civil law, the canon law, the common law, and the
+statute law. And from these, digested in their proper rank and
+subordination, to draw out one uniform law of the church is the purport
+of this book. When these laws do interfere and cross each other, the
+order of preference is this:--'The civil law submitteth to the canon
+law; both of these to the common law; and all three to the statute law.
+So that from any one or more of these, without all of them together, or
+from all of them together without attending to their comparative
+obligation, it is not possible to exhibit any distinct prospect of the
+English ecclesiastical constitution.' Under the head of statute law Burn
+includes 'the Thirty-nine Articles of Religion, agreed upon in
+Convocation in the year 1562; and in like manner the Rubric of the Book
+of Common Prayer, which, being both of them established by Acts of
+Parliament, are to be esteemed as part of the statute law.'"
+
+The first principle of the ecclesiastical law in England is the
+assertion of the supremacy of the crown, which in the present state of
+the constitution means the same thing as the supremacy of parliament.
+This principle has been maintained ever since the Reformation. Before
+the Reformation the ecclesiastical supremacy of the pope was recognized,
+with certain limitations, in England, and the Church itself had some
+pretensions to ecclesiastical freedom. The freedom of the Church is, in
+fact, one of the standing provisions of those charters on which the
+English constitution was based. The first provision of Magna Carta is
+_quod ecclesia Anglicana libera sit_. By the various enactments of the
+period of the Reformation the whole constitutional position of the
+Church, not merely with reference to the pope but with reference to the
+state, was definitely fixed. The legislative power of convocation was
+held to extend to the clergy only, and even to that extent required the
+sanction and assent of the crown. The common law courts controlled the
+jurisdiction of the ecclesiastical courts, claiming to have "the
+exposition of such statutes or acts of parliament as concern either the
+extent of the jurisdiction of these courts or the matters depending
+before them. And therefore if these courts either refuse to allow these
+acts of parliament, or expound them in any other sense than is truly and
+properly the exposition of them, the king's great courts of common law
+may prohibit and control them."
+
+The design of constructing a code of ecclesiastical laws was entertained
+during the period of the Reformation, but never carried into effect. It
+is alluded to in various statutes of the reign of Henry VIII., who
+obtained power to appoint a commission to examine the old ecclesiastical
+laws, with a view of deciding which ought to be kept and which ought to
+be abolished; and in the meantime it was enacted that "such canons,
+institutions, ordinances, synodal or provincial or other ecclesiastical
+laws or jurisdictions spiritual as be yet accustomed and used here in
+the Church of England, which necessarily and conveniently are requisite
+to be put in ure and execution for the time, not being repugnant,
+contrarient, or derogatory to the laws or statutes of the realm, nor to
+the prerogatives of the royal crown of the same, or any of them, shall
+be occupied, exercised, and put in ure for the time with this realm" (35
+Henry VIII. c. 16, 25 c. 19, 27 c. 8).
+
+The work was actually undertaken and finished in the reign of Edward VI.
+by a sub-committee of eight persons, under the name of the _Reformatio
+legum ecclesiasticarum_, which, however, never obtained the royal
+assent. Although the powers of the 25 Henry VIII. c. 1 were revived by
+the 1 Elizabeth c. 1, the scheme was never executed, and the
+ecclesiastical laws remained on the footing assigned to them in that
+statute--so much of the old ecclesiastical laws might be used as had
+been actually in use, and was not repugnant to the laws of the realm.
+
+The statement is, indeed, made by Sir R. Phillimore (_Ecclesiastical
+Law_, 2nd ed., 1895) that the "Church of England has at all times,
+before and since the Reformation, claimed the right of an independent
+Church in an independent kingdom, to be governed by the laws which she
+has deemed it expedient to adopt." This position can only be accepted if
+it is confined, as the authorities cited for it are confined, to the
+resistance of interference from abroad. If it mean that the Church, as
+distinguished from the kingdom, has claimed to be governed by laws of
+her own making, all that can be said is that the claim has been
+singularly unsuccessful. From the time of the Reformation no change has
+been made in the law of the Church which has not been made by the king
+and parliament, sometimes indirectly, as by confirming the resolutions
+of convocation, but for the most part by statute. The list of statutes
+cited in Sir R. Phillimore's _Ecclesiastical Law_ fills eleven pages. It
+is only by a kind of legal fiction akin to the "collegial" theory
+mentioned above, that the Church can be said to have deemed it expedient
+to adopt these laws.
+
+The terms on which the Church Establishment of Ireland was abolished, by
+the Irish Council Act of 1869, may be mentioned. By sect. 20 the present
+ecclesiastical law was made binding on the members for the time being of
+the Church, "as if they had mutually contracted and agreed to abide by
+and observe the same"; and by section 21 it was enacted that the
+ecclesiastical courts should cease after the 1st of January 1871, and
+that the ecclesiastical laws of Ireland, except so far as relates to
+matrimonial causes and matters, should cease to exist as law. (See also
+ENGLAND, CHURCH OF; ESTABLISHMENT; &c.)
+
+  AUTHORITIES.--The number of works on ecclesiastical law is very great,
+  and it must suffice here to mention a few of the more conspicuous
+  modern ones: Ferdinand Walter, _Lehrbuch des Kirchenrechts aller
+  christlichen Konfessionen_ (14th ed., Bonn, 1871); G. Phillips,
+  _Kirchenrecht_, Bde. i.-vii. (Regensburg, 1845-1872) incomplete; the
+  text-book by Cardinal Hergenroether (q.v.); P. Hinschius, _Kirchenrecht
+  der Katholiken und Protestanten in Deutschland_, 6 Bde. (Berlin, 1869
+  sqq.), only the Catholic part, a masterly and detailed survey of the
+  ecclesiastical law, finished; Sir Robert Phillimore, _Eccl. Law of the
+  Church of England_ (2nd ed., edited by Sir Walter Phillimore, 2 vols.,
+  London, 1895). For further references see CANON LAW, and the article
+  "Kirchenrecht" in Herzog-Hauck, _Realencyklopaedie_ (ed. Leipzig,
+  1901).
+
+
+
+
+ECCLESIASTICUS (abbreviated to _Ecclus._), the alternative title given
+in the English Bible to the apocryphal book otherwise called "The Wisdom
+of Jesus the son of Sirach." The Latin word _ecclesiasticus_ is,
+properly speaking, not a name, but an epithet meaning "churchly," so
+that it would serve as a designation of any book which was read in
+church or received ecclesiastical sanction, but in practice
+Ecclesiasticus has become a by-name for the Wisdom of Sirach. The true
+name of the book appears in the authorities in a variety of forms, the
+variation affecting both the author's name and the description of his
+book. The writer's full name is given in 1. 27 (Heb. text) as "Simeon
+the son of Jeshua (i.e. Jesus) the son of Eleazar the son of Sira." In
+the Greek text this name appears as "Jesus son of Sirach Eleazar"
+(probably a corruption of the Hebrew reading), and the epithet "of
+Jerusalem" is added, the translator himself being resident in Egypt. The
+whole name is shortened sometimes to "Son of Sira," _Ben Sira_ in
+Hebrew, _Bar Sira_ in Aramaic, and sometimes (as in the title prefixed
+in the Greek cod. B) to _Sirach_. The work is variously described as the
+_Words_ (Heb. text), the _Book_ (Talmud), the _Proverbs_ (Jerome), or
+the _Wisdom_ of the son of Sira (or Sirach).
+
+Of the date of the book we have only one certain indication. It was
+translated by a person who says that he "came into Egypt in the 38th
+year of Euergetes the king" (Ptolemy VII.), i.e. in 132 B.C., and that
+he executed the work some time later. The translator believed that the
+writer of the original was his own grandfather (or ancestor, [Greek:
+pappos]). It is therefore reasonable to suppose that the book was
+composed not later than the first half of the 2nd century B.C., or (if
+we give the looser meaning to [Greek: pappos]) even before the beginning
+of the century. Arguments for a pre-Maccabean date may be derived (a)
+from the fact that the book contains apparently no reference to the
+Maccabean struggles, (b) from the eulogy of the priestly house of Zadok
+which fell into disrepute during these wars for independence.
+
+In the Jewish Church Ecclesiasticus hovered on the border of the canon;
+in the Christian Church it crossed and recrossed the border. The book
+contains much which attracted and also much which repelled Jewish
+feeling, and it appears that it was necessary to pronounce against its
+canonicity. In the Talmud (Sanhedrin 100 b) Rabbi Joseph says that it is
+forbidden to read (i.e. in the synagogue) the book of ben Sira, and
+further that "if our masters had not hidden the book (i.e. declared it
+uncanonical), we might interpret the good things which are in it"
+(Schechter, _J. Q. Review_, iii. 691-692). In the Christian Church it
+was largely used by Clement of Alexandria (c. A.D. 200) and by St
+Augustine. The lists of the Hebrew canon, however, given by Melito (c.
+A.D. 180) and by Origen (c. A.D. 230) rightly exclude Ecclesiasticus,
+and Jerome (c. A.D. 390-400) writes: "Let the Church read these two
+volumes (Wisdom of Solomon and Ecclesiasticus) for the instruction of
+the people, not for establishing the authority of the dogmas of the
+Church" (_Praefatio in libros Salomonis_). In the chief MS. of the
+Septuagint, cod. B, Ecclesiasticus comes between Wisdom and Esther, no
+distinction being drawn between canonical and uncanonical. In the
+Vulgate it immediately precedes Isaiah. The council of Trent declared
+this book and the rest of the books reckoned in the Thirty-nine Articles
+as apocryphal to be canonical.
+
+The text of the book raises intricate problems which are still far from
+solution. The original Hebrew (rediscovered in fragments and published
+between 1896 and 1900) has come down to us in a mutilated and corrupt
+form. The beginning as far as iii. 7 is lost. There is a gap from xvi.
+26 to xxx. 11. There are marginal readings which show that two different
+recensions existed once in Hebrew. The Greek version exists in two
+forms--(a) that preserved in cod. B and in the other uncial MSS., (b)
+that preserved in the cursive codex 248 (Holmes and Parsons). The former
+has a somewhat briefer text, the latter agrees more closely with the
+Hebrew text. The majority of Greek cursives agree generally with the
+Latin Vulgate, and offer the fuller text in a corrupt form. The Syriac
+(Peshitta) version is paraphrastic, but on the whole it follows the
+Hebrew text. Owing to the mutilation of the Hebrew by the accidents of
+time the Greek version retains its place as the chief authority for the
+text, and references by chapter and verse are usually made to it.
+
+Bickell and D.S. Margoliouth have supposed that the Hebrew text
+preserved in the fragments is not original, but a retranslation from the
+Greek or the Syriac or both. This view has not commended itself to the
+majority of scholars, but there is at least a residuum of truth in it.
+The Hebrew text, as we have it, has a history of progressive corruption
+behind it, and its readings can often be emended from the Septuagint,
+e.g. xxxvii. 11 (read [Hebrew: umira] for the meaningless [Hebrew:
+umerer]). The Hebrew marginal readings occasionally seem to be
+translations from the Greek or Syriac, e.g. xxxviii. 4 ([Hebrew: bara
+shamaym] for [Greek: ektisen pharmaka]). More frequently, however,
+strange readings of the Greek and Syriac are to be explained as
+corruptions of our present Hebrew. Substantially our Hebrew must be
+pronounced original.
+
+The restoration of a satisfactory text is beyond our hopes. Even before
+the Christian era the book existed in two recensions, for we cannot
+doubt, after reading the Greek translator's preface, that the translator
+amplified and paraphrased the text before him. It is probable that at
+least one considerable omission must be laid to his charge, for the hymn
+preserved in the Hebrew text after ch. li. 12 is almost certainly
+original. Ancient translators allowed themselves much liberty in their
+work, and Ecclesiasticus possessed no reputation for canonicity in the
+2nd century B.C. to serve as a protection for its text. Much, however,
+may be done towards improving two of the recensions which now lie before
+us. The incomplete Hebrew text exists in four different MSS., and the
+study of the peculiarities of these had already proved fruitful. The
+Syriac text, made without doubt from the Hebrew, though often
+paraphrastic is often suggestive. The Greek translation, made within a
+century or half-century of the writing of the book, must possess great
+value for the criticism of the Hebrew text. The work of restoring true
+Hebrew readings may proceed with more confidence now that we have
+considerable portions of the Hebrew text to serve as a model. For the
+restoration of the Greek text we have, besides many Greek MSS., uncial
+and cursive, the old Latin, the Syro-Hexaplar, the Armenian, Sahidic and
+Ethiopic versions, as well as a considerable number of quotations in the
+Greek and Latin Fathers. Each of the two recensions of the Greek must,
+however, be separately studied, before any restoration of the original
+Greek text can be attempted.
+
+The uncertainty of the text has affected both English versions
+unfavourably. The Authorized Version, following the corrupt cursives, is
+often wrong. The Revised Version, on the other hand, in following the
+uncial MSS. sometimes departs from the Hebrew, while the Authorized
+Version with the cursives agrees with it. Thus the Revised Version (with
+codd. [Hebrew: alef]*, A, B, C) omits the whole of iii. 19, which the
+Authorized Version retains, but for the clause, "Mysteries are revealed
+unto the meek," the Authorized Version has the support of the Hebrew,
+Syriac and cod. 248. Sometimes both versions go astray in places in
+which the Hebrew text recommends itself as original by its vigour; e.g.
+in vii. 26, where the Hebrew is,
+
+  Hast thou a wife? abominate her not.
+  Hast thou a hated wife? trust not in her.
+
+Again in ch. xxxviii. the Hebrew text in at least two interesting
+passages shows its superiority over the text which underlies both
+English versions.
+
+                _Hebrew._                _Revised Version (similarly
+                                             Authorized Version)._
+
+  ver. 1.  Acquaint thyself with a       Honour a physician according
+           physician before thou have    to thy need of him with the
+           need of him.                  honours due unto him.
+
+  ver. 15. He that sinneth against his   He that sinneth before his
+           Maker will behave himself     Maker, let him fall into the
+           proudly against a physician.  hands of the physician.
+
+In the second instance, while the Hebrew says that the man who rebels
+against his Heavenly Benefactor will _a fortiori_ rebel against a human
+benefactor, the Greek text gives a cynical turn to the verse, "Let the
+man who rebels against his true benefactor be punished through the
+tender mercies of a quack." The Hebrew text is probably superior also in
+xliv. 1, the opening words of the eulogy of the Fathers: "Let me now
+praise favoured men," i.e. men in whom God's grace was shown. The Hebrew
+phrase is "men of grace," as in v. 10. The Greek text of v. 1, "famous
+men," seems to be nothing but a loose paraphrase, suggested by v. 2,
+"The Lord manifested in them great glory."
+
+In character and contents Ecclesiasticus resembles the book of Proverbs.
+It consists mainly of maxims which may be described in turn as moral,
+utilitarian and secular. Occasionally the author attacks prevalent
+religious opinions, e.g. the denial of free-will (xv. 11-20), or the
+assertion of God's indifference towards men's actions (xxxv. 12-19).
+Occasionally, again, Ben Sira touches the highest themes, and speaks of
+the nature of God: "He is All" (xliii. 27); "He is One from everlasting"
+(xlii. 21, Heb. text); "The mercy of the Lord is upon all flesh" (xviii.
+13). Though the book is imitative and secondary in character it contains
+several passages of force and beauty, e.g. ch. ii. (how to fear the
+Lord); xv. 11-20 (on free-will); xxiv. 1-22 (the song of wisdom); xlii.
+15-25 (praise of the works of the Lord); xliv. 1-15 (the well-known
+praise of famous men). Many detached sayings scattered throughout the
+book show a depth of insight, or a practical shrewdness, or again a
+power of concise speech, which stamps them on the memory. A few examples
+out of many may be cited. "Call no man blessed before his death" (xi.
+28); "He that toucheth pitch shall be defiled" (xiii. 1); "He hath not
+given any man licence to sin" (xv. 20); "Man cherisheth anger against
+man; and doth he seek healing from the Lord?" (xxviii. 3); "Mercy is
+seasonable ... as clouds of rain" (xxxv. 20); "All things are double one
+against another: and he hath made nothing imperfect" (xlii. 24, the
+motto of Butler's _Analogy_); "Work your work before the time cometh,
+and in his time he will give you your reward" (li. 30). In spite,
+however, of the words just quoted it cannot be said that Ben Sira
+preaches a hopeful religion. Though he prays, "Renew thy signs, and
+repeat thy wonders ... Fill Sion with thy majesty and thy Temple with
+thy glory" (xxxvi. 6, 14 [19], Heb. text), he does not look for a
+Messiah. Of the resurrection of the dead or of the immortality of the
+soul there is no word, not even in xli. 1-4, where the author exhorts
+men not to fear death. Like the Psalmist (Ps. lxxxviii. 10, 11) he asks,
+"Who shall give praise to the Most High in the grave?" In his maxims of
+life he shows a somewhat frigid and narrow mind. He is a pessimist as
+regards women; "From a woman was the beginning of sin; and because of
+her we all die" (xxv. 24). He does not believe in home-spun wisdom; "How
+shall he become wise that holdeth the plough?" (xxxviii. 25). Artificers
+are not expected to pray like the wise man; "In the handywork of their
+craft is their prayer" (v. 34). Merchants are expected to cheat; "Sin
+will thrust itself in between buying and selling" (xxvii. 2).
+
+  BIBLIOGRAPHY.--The literature of Ecclesiaticus has grown very
+  considerably since the discovery of the first Hebrew fragment in 1896.
+  A useful summary of it is found at the end of Israel Levi's article,
+  "Sirach," in the _Jewish Encyclopedia_. Eberhard Nestle's article in
+  Hastings's _Dictionary of the Bible_ is important for its
+  bibliographical information as well as in other respects. A complete
+  edition of the Hebrew fragments in collotype facsimile was published
+  jointly by the Oxford and Cambridge Presses in 1901. J.H.A. Hart's
+  edition of cod. 248 throws much light on some of the problems of this
+  book. It contains a fresh collation of all the chief authorities
+  (Heb., Syr., Syr.-Hex., Lat. and Gr.) for the text, together with a
+  complete textual commentary.
+
+  The account given in the _Synopsis_ attributed to Athanasius (Migne,
+  _P.G._, iv. 375-384) has an interest of its own. The beginning is
+  given in the Authorized Version as "A prologue made by an uncertain
+  author."     (W. E. B.)
+
+
+
+
+ECGBERT, or ECGBERHT (d. 839), king of the West Saxons, succeeded to the
+throne in 802 on the death of Beorhtric. It is said that at an earlier
+period in his life he had been driven out for three years by Offa and
+Beorhtric. The accession of Ecgbert seems to have brought about an
+invasion by AEthelmund, earl of the Hwicce, who was defeated by Weoxtan,
+earl of Wiltshire. In 815 Ecgbert ravaged the whole of the territories
+of the West Welsh, which probably at this time did not include much more
+than Cornwall. The next important occurrence in the reign was the defeat
+of Beornwulf of Mercia at a place called Ellandun in 825. After this
+victory Kent, Surrey, Sussex and Essex submitted to Wessex; while the
+East Anglians, who slew Beornwulf shortly afterwards, acknowledged
+Ecgbert as overlord. In 829 the king conquered Mercia, and Northumbria
+accepted him as overlord. In 830 he led a successful expedition against
+the Welsh. In 836 he was defeated by the Danes, but in 838 he won a
+battle against them and their allies the West Welsh at Hingston Down in
+Cornwall. Ecgbert died in 839, after a reign of thirty-seven years, and
+was succeeded by his son AEthelwulf. A somewhat difficult question has
+arisen as to the parentage of Ecgbert. Under the year 825 the Chronicle
+states that in his eastern conquests Ecgbert recovered what had been
+the rightful property of his kin. The father of Ecgbert was called
+Ealhmund, and we find an Ealhmund, king in Kent, mentioned in a charter
+dated 784, who is identified with Ecgbert's father in a late addition to
+the Chronicle under the date 784. It is possible, however, that the
+Chronicle in 825 refers to some claim through Ine of Wessex from whose
+brother Ingeld Ecgbert was descended.
+
+  See _Anglo-Saxon Chronicle_, edited by Earle and Plummer (Oxford,
+  1899); W. de G. Birch, _Cartularium Saxonicum_ (London, 1885-1893).
+  Also a paper by Sir H.H. Howorth in _Numismatic Chronicle_, third
+  series, vol. xx. pp. 66-87 (reprinted separately, London, 1900), where
+  attention is called to the peculiar dating of several of Ecgbert's
+  charters, and the view is put forward that he remained abroad
+  considerably later than the date given by the Chronicle for his
+  accession. On the other hand a charter in Birch, _Cart. Sax._,
+  purporting to date from 799, contains the curious statement that peace
+  was made between Coenwulf and Ecgbert in that year.
+
+
+
+
+ECGBERT, or ECGBERHT (d. 766), archbishop of York, was made bishop of
+that see in 734 by Ceolwulf, king of Northumbria, succeeding Wilfrid II.
+on the latter's resignation. The pall was sent him in 735 and he became
+the first northern archbishop after Paulinus. He was the brother of
+Eadberht, who ruled Northumbria 737-758. He was the recipient of the
+famous letter of Bede, dealing with the evils arising from spurious
+monasteries. Ecgberht himself wrote a _Dialogus Ecclesiasticae
+Institutionis_, a _Penitentiale_ and a _Pontificale_. He was a
+correspondent of St Boniface, who asks him to support his censure of
+AEthelbald of Mercia.
+
+  See Bede, _Continuatio_, sub. ann. 732, 735, 766, and _Epistola ad
+  Ecgberctum_ (Plummer, Oxford, 1896); _Chronicle_, sub ann. 734, 735,
+  738, 766 (Earle and Plummer, Oxford, 1899); Haddan and Stubbs,
+  _Councils and Ecclesiastical Documents_ (Oxford, 1869-1878), iii.
+  403-431; _Proceedings of Surtees Society_ (Durham, 1853).
+
+
+
+
+ECGFRITH (d. 685), king of Northumbria, succeeded his father Oswio in
+671. He was married to AEthelthryth, daughter of Anna of East Anglia,
+who, however, took the veil shortly after Ecgfrith's accession, a step
+which possibly led to his long quarrel with Wilfrid archbishop of York.
+Ecgfrith married a second wife, Eormenburg, before 678, the year in
+which he expelled Wilfrid from his kingdom. Early in his reign he
+defeated the Picts who had risen in revolt. Between 671 and 675 Ecgfrith
+defeated Wulfhere of Mercia and seized Lindsey. In 679, however, he was
+defeated by AEthelred of Mercia, who had married his sister Osthryth, on
+the river Trent. Ecgfrith's brother AElfwine was killed in the battle,
+and the province of Lindsey was given up when peace was restored at the
+intervention of Theodore of Canterbury. In 684 Ecgfrith sent an
+expedition to Ireland under his general Berht, which seems to have been
+unsuccessful. In 685, against the advice of Cuthbert, he led a force
+against the Picts under his cousin Burde, son of Bile, was lured by a
+feigned flight into their mountain fastnesses, and slain at
+Nechtanesmere (now Dunnichen) in Forfarshire. Bede dates the beginning
+of the decline of Northumbria from his death. He was succeeded by his
+brother Aldfrith.
+
+  See Eddius, _Vita Wilfridi_ (Raine, _Historians of Church of York_,
+  Rolls, Series, London, 1879-1894), 19, 20, 24, 34, 39, 44; Bede,
+  _Hist. Eccl._ (Plummer, Oxford, 1896), iii. 24, iv. 5, 12, 13, 18, 19,
+  21, 26.
+
+
+
+
+ECGONINE, in chemistry, C9H15NO3, a cycloheptane derivative with a
+nitrogen bridge. It is obtained by hydrolysing cocaine with acids or
+alkalis, and crystallizes with one molecule of water, the crystals
+melting at 198 deg. to 199 deg. C. It is laevo-rotatory, and on warming with
+alkalis gives iso-ecgonine, which is dextro-rotatory. It is a tertiary
+base, and has also the properties of an acid and an alcohol. When boiled
+with caustic baryta it gives methylamine. It is the carboxylic acid
+corresponding to tropine, for it yields the same products on oxidation,
+and by treatment with phosphorus pentachloride is converted into
+anhydroecgonine, C9H13NO2, which, when heated to 280 deg. C. with
+hydrochloric acid, splits out carbon dioxide and yields tropidine,
+C8H13N. Anhydroecgonine melts at 235 deg. C., and has an acid and a basic
+character. It is an unsaturated compound, and on oxidation with
+potassium permanganate gives succinic acid. It is apparently a tropidine
+monocarboxylic acid, for on exhaustive methylation it yields
+cycloheptatriene-1.3.5-carboxylic acid-7. Sodium in amyl alcohol
+solution reduces it to hydroecgonidine C9H15NO2, while moderate
+oxidation by potassium permanganate converts it into _norecgonine_. The
+presence of the heptamethylene ring in these compounds is shown by the
+production of suberone by the exhaustive methylation, &c., of
+hydroecgonidine ethyl ester (see POLYMETHYLENES and TROPINE). The above
+compounds may be represented as:
+
+  CH2--CH----CH COOH   CH2--CH----CH COOH   CH2--CH------CH COOH
+  |    |     |         |    |     |         |    |       |
+  |    N CH3 CH OH     |    N CH3 CH        |    N CH3 CH2
+  |    |     |         |    |     ||        |    |       |
+  CH2--CH----CH2       CH2--CH----CH        CH2--CH------CH2
+     Ecgonine           Anhydroecgonine        Hydroecgonine
+
+
+
+
+ECHEGARAY Y EIZAGUIRRE, JOSE (1833-   ), Spanish mathematician,
+statesman and dramatist, was born at Madrid in March 1833, and was
+educated at the grammar school of Murcia, whence he proceeded to the
+Escuela de Caminos at the capital. His exemplary diligence and unusual
+mathematical capacity were soon noticed. In 1853 he passed out at the
+head of the list of engineers, and, after a brief practical experience
+at Almeria and Granada, was appointed professor of pure and applied
+mathematics in the school where he had lately been a pupil. His
+_Problemas de geometria analitica_ (1865) and _Teorias modernas de la
+fisica unidad de las fuerzas materiales_ (1867) are said to be esteemed
+by competent judges. He became a member of the Society of Political
+Economy, helped to found _La Revista_, and took a prominent part in
+propagating Free Trade doctrines in the press and on the platform. He
+was clearly marked out for office, and when the popular movement of 1868
+overthrew the monarchy, he resigned his post for a place in the
+revolutionary cabinet. Between 1867 and 1874 he acted as minister of
+education and of finance; upon the restoration of the Bourbon dynasty he
+withdrew from politics, and won a new reputation as a dramatist.
+
+As early as 1867 he wrote _La Hija natural_, which was rejected, and
+remained unknown till 1877, when it appeared with the title of _Para tal
+culpa tal pena_. Another play, _La Ultima Noche_, also written in 1867,
+was produced in 1875; but in the latter year Echegaray was already
+accepted as the successful author of _El Libro talonario_, played at the
+Teatro de Apolo on the 18th of February 1874, under the transparent
+pseudonym of Jorge Hayaseca. Later in the same year Echegaray won a
+popular triumph with _La Esposa del vengador_, in which the good and bad
+qualities--the clever stagecraft and unbridled extravagance--of his
+later work are clearly noticeable. From 1874 onwards he wrote, with
+varying success, a prodigious number of plays. Among the most favourable
+specimens of his talent may be mentioned _En el puno de la espada_
+(1875); _O locura o santidad_ (1877), which has been translated into
+Swedish and Italian; _En el seno de la muerte_ (1879), of which there
+exists an admirable German version by Fastenrath. _El gran Galeoto_
+(1881), perhaps the best of Echegaray's plays in conception and
+execution, has been translated into several languages, and still holds
+the stage. The humorous proverb, _?Piensa mal y acertaras?_ exemplifies
+the author's limitations, but the attempt is interesting as an instance
+of ambitious versatility. His susceptibility to new ideas is illustrated
+in such pieces as _Mariana_ (1892), _Mancha que limpia_ (1895), _El Hijo
+de Don Juan_ (1892), and _El Loco Dios_ (1900): these indicate a close
+study of Ibsen, and _El Loco Dios_ more especially might be taken for an
+unintentional parody of Ibsen's symbolism.
+
+Echegaray succeeded to the literary inheritance of Lopez de Ayala and of
+Tamayo y Baus; and though he possesses neither the poetic imagination of
+the first nor the instinctive tact of the second, it is impossible to
+deny that he has reached a larger audience than either. Not merely in
+Spain, but in every land where Spanish is spoken, and in cities as
+remote from Madrid as Munich and Stockholm, he has met with an
+appreciation incomparably beyond that accorded to any other Spanish
+dramatist of recent years. But it would be more than usually rash to
+prophesy that this exceptional popularity will endure. There have been
+signs of a reaction in Spain itself, and Echegaray's return to politics
+in 1905 was significant enough. He applies his mathematics to the
+drama; no writer excels him in artful construction, in the arrangement
+of dramatic scenes, in mere theatrical technique, in the focusing of
+attention on his chief personages. These are valuable gifts in their
+way, and Echegaray has, moreover, a powerful, gloomy imagination, which
+is momentarily impressive. In the drawing of character, in the invention
+of felicitous phrase, in the contrivance of verbal music, he is
+deficient. He alternates between the use of verse and prose; and his
+hesitancy in choosing a medium of expression is amply justified, for the
+writer's prose is not more distinguished than his verse. These serious
+shortcomings may explain the diminution of his vogue in Spain; they will
+certainly tell against him in the estimate of posterity.     (J. F.-K.)
+
+
+
+
+ECHELON (Fr. from _echelle_, ladder), in military tactics, a formation
+of troops in which each body of troops is retired on, but not behind,
+the flank of the next in front, the position of the whole thus
+resembling the steps of a staircase. To form echelon from line, the
+parts of the line move off, each direct to its front, in succession, so
+that when the formation is completed the rightmost body, for example, is
+farthest advanced, the one originally next on its left is to the left
+rear, a third is to the left rear of the second, and so on. The word is
+also used more loosely to express successive lines, irrespective of
+distances and relative positions, e.g. the "second echelon of ammunition
+supply," which is fully a day's march behind the first.
+
+
+
+
+ECHIDNA, or PORCUPINE ANT-EATER (_Echidna aculeata_), one of the few
+species of Monotremata, the lowest subclass of Mammalia, forming the
+family Echidnidae. It is a native of Australia, where it chiefly abounds
+in New South Wales, inhabiting rocky and mountainous districts, where it
+burrows among the loose sand, or hides itself in crevices of rocks. In
+size and appearance it bears a considerable resemblance to the hedgehog,
+its upper surface being covered over with strong spines directed
+backwards, and on the back inwards, so as to cross each other on the
+middle line. The spines in the neighbourhood of the tail form a tuft
+sufficient to hide that almost rudimentary organ. The head is produced
+into a long tubular snout, covered with skin for the greater part of its
+length. The opening of the mouth is small, and from it the echidna puts
+forth its long slender tongue, lubricated with a viscous secretion, by
+means of which it seizes the ants and other insects on which it feeds.
+It has no teeth. Its legs are short and strong, and form, with its broad
+feet and large solid nails, powerful burrowing organs. In common with
+the other monotremes, the male echidna has its heel provided with a
+sharp hollow spur, connected with a secreting gland, and with muscles
+capable of pressing the secretion from the gland into the spur. It is a
+nocturnal or crepuscular animal, generally sleeping during the day, but
+showing considerable activity by night. When attacked it seeks to escape
+either by rolling itself into a ball, its erect spines proving a
+formidable barrier to its capture, or by burrowing into the sand, which
+its powerful limbs enable it to do with great celerity. "The only mode
+of carrying the creature," writes G. Bennett (_Gatherings of a
+Naturalist in Australasia_), "is by one of the hind legs; its powerful
+resistance and the sharpness of the spines will soon oblige the captor,
+attempting to seize it by any other part of the body, to relinquish his
+hold." In a younger stage of their development, however, the young are
+carried in a temporary abdominal pouch, to which they are transferred
+after hatching, and into which open the mammary glands. The echidnas are
+exceedingly restless in confinement, and constantly endeavour by
+burrowing to effect their escape. From the quantity of sand and mud
+always found in the alimentary canal of these animals, it is supposed
+that these ingredients must be necessary to the proper digestion of
+their insect food.
+
+There are two varieties of this species, the Port Moresby echidna and
+the hairy echidna. The last-mentioned is found in south-eastern New
+Guinea, Australia and Tasmania. In all the spines are mixed with hair;
+in the Tasmanian race they are nearly hidden by the long harsh fur. Of
+the three-clawed echidnas (_Proechidna_) confined to New Guinea there
+are two species, Bruijn's echidna (_P. bruijnii_), discovered in 1877 in
+the mountains on the north-east coast at an elevation of 3500 ft., and
+the black-spined echidna (_P. nigroaculeata_) of larger size--the type
+specimen measuring 31 in., as against 24 in.--with shorter
+claws.
+
+
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Encyclopaedia Britannica, 11th
+Edition, Volume 8, Slice 9, by Various
+
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