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+*** START OF THE PROJECT GUTENBERG EBOOK 13358 ***
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 803
+
+
+
+
+NEW YORK, May 23, 1891
+
+Scientific American Supplement. Vol. XXXI., No. 803.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+
+         *       *       *       *       *
+
+
+
+
+TABLE OF CONTENTS.
+
+
+I.    ASTRONOMY.--The Great Equatorial of the Paris Observatory.--
+      The new telescope recently put in use in Paris.--Description of
+      the instrument and of its effects.--3 illustrations
+
+II.   CHEMISTRY.--An Apparatus for Heating Substances in Glass
+      Tubes under Pressure.--By H. PEMBERTON, Jr.--A simple apparatus
+      for effecting this purpose, avoiding risk of personal injury.--
+      2 illustrations
+
+      Table of Atomic Weights.--A revised table of atomic weights,
+      giving the results of the last determinations, and designed for
+      every-day use
+
+      Testing Cement.--A laboratory process for testing Portland cement
+
+III.  CIVIL ENGINEERING.--The Compressed Air System of Paris.
+      --An elaborate review of this great installation for the transmission
+      of power.--The new compressed air station, with full details
+      of performances of apparatus, etc.--10 illustrations
+
+IV.   ENTOMOLOGY.--Report on Insects.--Continuation of this report
+      on noxious insects.--Their habits and how to cope with them.
+      --18 illustrations
+
+V.    FLORICULTURE.--Lily of the Valley.--Practical notes on the
+      cultivation of this popular flower.--How to raise it and force the
+      growth
+
+VI.   MATHEMATICS.--The Conic Sections.--By Prof. C.W.
+      MACCORD.--Examination of the four conic sections with a general
+      definition applicable to all.--6 illustrations
+
+VII.  MECHANICAL ENGINEERING.--The Builders of the Steam
+      Engine--The Founders of Modern Industries and Nations.--By Dr.
+      R.H. THURSTON.--Prof. Thurston's address before the Centennial
+      Celebration of the American Patent System at Washington,
+      D.C.--The early history of the steam engine and its present position
+      in the world
+
+VIII. MISCELLANEOUS.--The Breeds of Dogs.--Popular description
+      of the different breeds of dogs most affected by amateurs.--6
+      illustrations
+
+IX.   NAVAL ENGINEERING.--Modern Armor.--By F.R. BRAINARD.--The
+      development of modern ship armor, from laminated
+      sandwiched and compound types to the present solid armor.--9
+      illustrations
+
+X.    PISCICULTURE.--Restocking the Seine with Fish.--The introduction
+      of 40,000 fry of California trout and salmon, designed to restock
+      the Seine, depopulated of fish by explosions of dynamite
+      used in breaking up the ice.--1 illustration
+
+XI.   RAILWAY ENGINEERING.--Improved Hand Car.--A novelty
+      in the construction of hand cars, avoiding the production of a
+      dead center.--1 illustration
+
+XII.  TECHNOLOGY.--The Tanning Materials of Europe.--The natural
+      tanning materials and pathological or abnormal growth tanning
+      materials described and classified, with relative power
+
+
+         *       *       *       *       *
+
+
+
+
+THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.
+
+
+The great instrument which has just completed the installation of our
+national observatory is constructed upon the same principle as the
+elbowed equatorial, 11 in. in diameter, established in 1882, according
+to the ingenious arrangement devised as long ago as 1872, by Mr.
+Loewy, assistant director of the Paris Observatory.
+
+We shall here recall the fact that the elbowed equatorial consists of
+two parts joined at right angles. One of these is directed according
+to the axis of the world, and is capable of revolving around its own
+axis, and the other, which is at right angles to it, is capable of
+describing around the first a plane representing the celestial
+equator. At the apex of the right angle there is a plane mirror of
+silvered glass inclined at an angle of 45 deg. with respect to the
+optical axis, and which sends toward the ocular the image coming from
+the objective and already reflected by another and similar plane
+mirror. The objective and this second mirror (which is inclined at an
+angle of 45 deg.) are placed at the extremity of the external part of
+the tube, and form part of a cube, movable around the axis of the
+instrument at right angles with the axis of the world. The diagram in
+Fig. 3 will allow the course of a luminous ray coming from space to be
+easily understood. The image of the star, A, toward which the
+instrument is directed, traverses the objective, B C, is reflected
+first from the mirror, B D, and next from the central mirror, E F, and
+finally reaches O, at the ocular where the observer is stationed.
+
+This new equatorial differs from the first model by its much larger
+dimensions and its extremely remarkable mechanical improvements. The
+optical part, which is admirably elaborated, consists of a large
+astronomical objective 24 in. in diameter, and of a photographic
+objective of the same aperture, capable of being substituted, one for
+the other, according to the nature of the work that it is desired to
+accomplish by the aid of this colossal telescope, the total length of
+which is 59 ft. The two plane mirrors which complete the optical
+system have, respectively, diameters of 34 in. and 29 in. These two
+magnificent objectives and the two mirrors were constructed by the
+Brothers Henry, whose double reputation as astronomers and opticians
+is so universally established. The mechanical part is the successful
+work of Mr. Gautier, who has looked after every detail with the
+greatest care, and has thus realized a true _chef d'oeuvre_. The
+colossal instrument, the total weight of which is 26,400 lb., is
+maneuvered by hand with the greatest ease. A clockwork movement, due
+to the same able manufacturer, is capable, besides, of moving the
+instrument with all the precision desirable, and of permitting it to
+follow the stars in their travel across the heavens. A star appearing
+in the horizon can thus be observed from its rising to its setting.
+The astronomer, his eye at the ocular, is always conveniently seated
+at the same place, observing the distant worlds, rendered immovable,
+so to speak, in the field of the instrument. For stars which, like the
+moon and the planets, have a course different from the diurnal motion,
+it is possible to modify the running of the clockwork, so that they
+can thus be as easily followed as in the preceding case. Fig. 1 gives
+a general view of the new installation, for which it became necessary
+to build a special edifice 65 ft. in height on the ground south of the
+observatory bordering on the Arago Boulevard. A large movable
+structure serves for covering the external part of the instrument.
+This structure rests on rails, upon which it slides toward the south
+when it is desired to make observations. It will be seen from the
+figure how the principal axis of the instrument rests upon the two
+masonry pillars, one of which is 49 ft. and the other 13 ft. in
+height.
+
+[Illustration: FIG 1.--THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.]
+
+The total cost of the pavilion, rolling structure, and instrument
+(including the two objectives) will amount to about $80,000 after the
+new equatorial has been provided with the scientific apparatus that
+necessarily have to accompany it for the various and numerous
+applications to which the use of it will give rise.
+
+[Illustration: FIG 2.--OCULAR OF THE GREAT EQUATORIAL.]
+
+Fig. 2 shows us the room in the observatory in which the astronomer,
+seated in his chair, is completely protected against the inclemencies
+of the weather. Here, with his eye applied to the ocular, he can,
+without changing position (owing to all the handles that act at his
+will upon the many transmissions necessary for the maneuvering),
+direct his instrument unaided toward every point of the heavens with
+wonderful sureness and precision. The observer has before him on the
+same plane two divided circles, one of which gives the right
+ascensions and the other the declinations, and which he consults at
+each observation for the exact orientation of the equatorial.
+
+[Illustration: FIG. 3.--DIAGRAM SHOWING THE COURSE OF A LUMINOUS RAY
+IN THE GREAT EQUATORIAL.]
+
+All the readings are done by the aid of electric lamps of very small
+dimensions, supplied by accumulators, and which are lighted at will.
+Each of these lamps is of one candle power; two of them are designed
+for the reading of the two circles of right ascension and of
+declination; a third serves for the reading of the position circle of
+the micrometer; two others are employed for the reading of the drums
+fixed upon the micrometric screws; four others serve for rendering the
+spider threads of the reticule brilliant upon a black ground; and
+still another serves for illuminating the field of the instrument
+where the same threads remain black upon a luminous ground. The
+currents that supply these lamps are brought over two different
+circuits, in which are interposed rheostats that permit of graduating
+the intensity of the light at will.
+
+Since the installation of the first model of an elbowed equatorial of
+11 in. aperture, in 1882, at the Paris Observatory, the numerous and
+indisputable advantages of this sort of instrument have led a certain
+number of observatories to have similar, but larger, instruments
+constructed. In France, the observatories of Alger, Besancon, and
+Lyons have telescopes of this kind, the objectives of which have
+diameters of from 12 in. to 13 in., and which have been used for
+several years past in equatorial observations of all kinds. The Vienna
+Observatory has for the last two years been using an instrument of
+this kind whose objective has an aperture of 15 inches. Another
+equatorial of the same kind, of 16 in. aperture, is now in course of
+construction for the Nice Observatory, where it will be especially
+employed as a seeker of exceptional power--a role to which this kind
+of instrument lends itself admirably. The optical part of all these
+instruments was furnished by the Messrs. Henry, and the mechanical
+part by Mr. Gautier.
+
+The largest elbowed equatorial is, therefore, that of the Paris
+Observatory. Its optical power, moreover, corresponds perfectly to its
+huge dimensions. The experimental observations which have already been
+made with it fully justify the hopes that we had a right to found upon
+the professional skill of the eminent artists to whom we owe this
+colossal instrument. The images of the stars were given with the
+greatest sharpness, and it was possible to study the details of the
+surface of the moon and other planets, and several star clusters, in
+all their peculiarities, in the most remarkable manner.
+
+When it shall become possible to make use of this equatorial for
+celestial photography, there is no doubt that we shall obtain the most
+important results. As regards the moon, in particular, the
+photographing of which has already made so great progress, its direct
+image at the focus of the large 24 in. photographic objective will
+have a diameter of 11 in., and, being magnified, will be capable of
+giving images of more than 3 ft. in diameter.--_La Nature_.
+
+       *       *       *       *       *
+
+
+
+
+LILY OF THE VALLEY.
+
+
+There is no flower more truly and universally popular than the lily of
+the valley. What can be more delicious and refreshing than the scent
+of its fragrant flowers? What other plant can equal in spring the
+attractiveness of its pillars of pure white bells half hidden in their
+beautiful foliage? There are few gardens without a bed of lily of the
+valley, but too often the place chosen for it is some dark corner
+where nothing else would be expected to grow, but it is supposed as a
+matter of course that "it will do for a lily bed." The consequence is
+that although these lilies are very easy things to cultivate, as
+indeed they ought to be, seeing that they grow wild in the woods of
+this and other countries, yet one hears so often from those who take
+only a slight interest in practical gardening, "I have a lily bed, but
+I scarcely ever get any lilies." Wild lilies are hardly worth the
+trouble of gathering, they are so thin and poor; it is interesting to
+find a plant so beautiful and precious in the garden growing wild in
+the woods, but beyond that the flowers themselves are worth but very
+little. This at once tells us an evident fact about the lily of the
+valley, viz., that it does require cultivation. It is not a thing to
+be left alone in a dark and dreary corner to take care of itself
+anyhow year after year. People who treat it so deserve to be
+disappointed when in May they go to the lily bed and find plenty of
+leaves, but no flowers, or, if any, a few poor, weak attempts at
+producing blossoms, which ought to be so beautiful and fragrant.
+
+One great advantage of this lovely spring flower is that it can be so
+readily and easily forced. Gardeners in large places usually spend
+several pounds in the purchase of crowns and clumps of the lily of the
+valley, which they either import direct from foreign nurserymen or
+else procure from their own dealer in such things, who imports his
+lilies in large quantities from abroad. But we may well ask, Have
+foreign gardeners found out some great secret in the cultivation of
+this plant? Or is their climate more suitable for it? Or their soil
+adapted to growing it and getting it into splendid condition for
+forcing? It is impossible that the conditions for growing large and
+fine heads of this lily can be in any way better in Berlin or
+elsewhere than they are in our own land, unless greater heat in summer
+than we experience in England is necessary for ripening the growths in
+autumn.
+
+There is another question certainly as to varieties; one variety may
+be superior to another, but surely if so it is only on the principle
+of the survival of the fittest, that is to say, by carefully working
+on the finest forms only and propagating from them, a strong and
+vigorous stock may be the result, and this stock may be dignified with
+a special name. For my own part what I want is to have a great
+abundance of lily of the valley from February till the out-door season
+is over. To do this with imported clumps would, of course, be most
+costly, and far beyond what any person ought to spend on mere flowers.
+Though it must be remembered that it is an immense advantage to the
+parish priest to be able to take bright and sweet flowers to the
+bedside of the sick, or to gratify the weary spirit of a confirmed
+invalid, confined through all the lovely spring time to the narrow
+limits of a dull room, with the fragrant flowers of the lily of the
+valley. I determined, therefore, that I would have an abundance of
+early lilies, and that they should not be costly, but simply produced
+at about the same expense as any other flowers, and I have been very
+successful in accomplishing this by very simple means. First of all,
+it is necessary to have the means of forcing, that is to say the
+required heat, which in my case is obtained from an early vinery. I
+have seen lilies forced by pushing the clumps in under the material
+for making a hot bed for early cucumbers, the clumps being drawn out,
+of course, as soon as the flowers had made a good start. They have
+then to be carefully and very gradually exposed to full light, but
+often, although fine heads of bloom may be produced in this way, the
+leaves will be few and poor.
+
+My method is simply this: In the kitchen garden there is the old
+original bed of lilies of the valley in a corner certainly, but not a
+dark corner. This is the reservoir, as were, from whence the regular
+supply of heads for special cultivation is taken. This large bed is
+not neglected and left alone to take care of itself, but carefully
+manured with leaf mould and peat moss manure from the stable every
+year. Especially the vacant places made by taking out the heads for
+cultivation are thus filled up.
+
+Then under the east wall another piece of ground is laid out and
+divided into four plots. When I first began to prepare for forcing I
+waited four years, and had one plot planted with divided heads each
+year. Clumps are taken up from the reserve bed and then shaken out and
+the heads separated, each with its little bunch of fibrous roots. They
+are then carefully planted in one of the plots about 4 in. or 5 in.
+apart, the ground having previously been made as light and rich as
+possible with plenty of leaf mould. I think the best time for doing
+this is in autumn, after the leaves have turned yellow and have rotted
+away; but frequently the operation has been delayed till spring,
+without much difference in the result.
+
+Asparagus is usually transplanted in spring, and there is a wonderful
+affinity between the two plants, which, of course, belong to the same
+order. It was a long time to wait--four years--but I felt there was no
+use in being in too great a hurry, and every year the plants
+manifestly improved, and the buds swelled up nicely and looked more
+plump each winter when the leaves were gone. It must be remembered
+also that a nice crop of flowers could be gathered each year. When the
+fourth year came, the first plot was divided up into squares about 2
+ft. each way, and taken up before any hard frost or snow had made
+their appearance, and put away on the floor of an unused stable. From
+the stable they are removed as required in the squares to the vinery,
+where they grow beautifully, not sending up merely fine heads of bloom
+without a vestige of leaf, but growing as they would in spring out of
+doors with a mass of foliage, among which one has to search for the
+spikes of flower, so precious for all sorts of purposes at that early
+season of the year.
+
+The spikes produced in this way do not equal in thickness and
+substance of petal the flowers which come from more carefully prepared
+clumps imported from Berlin, but they are fine and strong, and above
+all most abundant. I can not only supply the house and small vases for
+the church, but also send away boxes of the flowers to friends at a
+distance, besides the many gifts which can be made to those who are
+ill or invalids. Few gifts at such a time are more acceptable than a
+fragrant nosegay of lily of the valley. In order to keep the supply of
+prepared roots ready year after year, a plot of ground has only to be
+planted each autumn, so that in the rotation of years it may be ready
+for forcing when its turn shall come.
+
+As the season advances, as every one knows who has attempted to force
+the lily of the valley, much less time is taken in bringing the
+flowers to perfection under precisely the same circumstances as those
+in which the first sods are forced. In February or earlier the buds
+are more unwilling to start; there seems to be a natural repugnance
+against being so soon forced out of the winter's sleep and rest. But
+when the flowers do come, they are nearly as fine and their leaves are
+quite as abundant in this way of forcing as from the pieces introduced
+much later into heat. It would be easy to preserve the squares after
+all the flowers are gathered, but I found that they would not, like
+strawberries, kindly furnish forth another crop later on in the year,
+and, therefore, mine are flung away; and I have often pitied the
+tender leaves in the frost and snow after their short sojourn in the
+hot climate of the vinery. But the reserve bed will always supply an
+ample quantity of fresh heads, and it is best to take the new plants
+for preparation in the kitchen garden from this reserve bed.
+
+This very simple method of forcing lilies of the valley is within the
+reach of any one who has even a small garden and a warm house, and
+these two things are becoming more and more common among us every
+day.--_A Gloucestershire Parson, in The Garden_.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12820.]
+
+
+
+
+REPORT ON INSECTS.
+
+THE ONION MAGGOT.
+
+_Phorbia ceparum_ (Meig.)
+
+
+Early in June a somewhat hairy fly, Fig. 9, may be seen flying about,
+and depositing its eggs on the leaves of the young onion plants, near
+the roots, Fig. 10.
+
+[Illustration: FIG. 9.]
+
+Dr. Fitch describes this fly as follows: "It has a considerable
+resemblance to the common house fly, though when the two are placed
+side by side, this is observed as being more slender in its form. The
+two sexes are readily distinguished from each other by the eyes, which
+in the males are close together, and so large as to occupy almost the
+whole surface of the head, while in the females they are widely
+separated from each other. These flies are of an ash gray color, with
+the head silvery, and a rusty black stripe between the eyes, forked at
+its hind end. And this species is particularly distinguished by having
+a row of black spots along the middle of the abdomen or hind body,
+which sometimes run into each other, and then forming a continuous
+stripe.
+
+"This row of spots is quite distinct in the male, but in the female is
+very faint, or is often wholly imperceptible. This fly measured 0.22
+to 0.25 inch in length, the females being usually rather larger than
+the males." The eggs are white, smooth, somewhat oval in outline, and
+about one twenty-fifth of an inch in length. Usually not more than
+half a dozen are laid on a single plant, and the young maggot burrows
+downward within the sheath, leaving a streak of pale green to indicate
+its path, and making its way into the root, devours all except the
+outer skin.
+
+[Illustration: FIG. 10.]
+
+The maggots reach their full growth in about two weeks, when they are
+about one-third of an inch long, white and glossy, tapering from the
+posterior end to the head, which is armed with a pair of black,
+hook-like jaws. The opposite end is cut off obliquely and has eight
+tooth-like projections around the edge, and a pair of small brown
+tubercles near the middle. Fig. 11 shows the eggs, larva, and pupa,
+natural size and enlarged.
+
+[Illustration: FIG. 11.]
+
+They usually leave the onions and transform to pupæ within the ground.
+The form of the pupa does not differ very much from the maggot, but
+the skin has hardened and changed to a chestnut brown color, and they
+remain in this stage about two weeks in the summer, when the perfect
+flies emerge. There are successive broods during the season, and the
+winter is passed in the pupa stage.
+
+The following remedies have been suggested:
+
+Scattering dry, unleached wood ashes over the plants as soon as they
+are up, while they are wet with dew, and continuing this as often as
+once a week through the month of June, is said to prevent the deposit
+of eggs on the plants.
+
+Planting the onions in a new place as remote as possible from where
+they were grown the previous year has been found useful, as the flies
+are not supposed to migrate very far.
+
+Pulverized gas lime scattered along between the rows has been useful
+in keeping the flies away.
+
+Watering with liquid from pig pens collected in a tank provided for
+the purpose, was found by Miss Ormerod to be a better preventive than
+the gas lime.
+
+When the onions have been attacked and show it by wilting and changing
+color, they should either be taken up with a trowel and burned, or
+else a little diluted carbolic acid, or kerosene oil, should be
+dropped on the infested plants to run down them and destroy the
+maggots in the roots and in the soil around them.
+
+Instead of sowing onion seed in rows, they should be grown in hills,
+so that the maggots, which are footless, cannot make their way from
+one hill to another.
+
+
+THE CABBAGE BUTTERFLY.
+
+_Pieris rapae_ (Linn.)
+
+
+In the New England States there are three broods of this insect in a
+year, according to Mr. Scudder, the butterflies being on the wing in
+May, July, and September; but as the time of the emergence varies, we
+see them on the wing continuously through the season.
+
+[Illustration: FIG. 12.]
+
+The expanded wings, Fig. 12, male, measure about two inches, are white
+above, with the base dusky. Both sexes have the apex black and a black
+spot a little beyond the middle, and the female, Fig. 13, has another
+spot below this. The under side of the fore wings is white, yellowish
+toward the apex, and with two black spots in both sexes corresponding
+to those on the upper side of the female. A little beyond the middle
+of the costa, on the hind wings, is an irregular black spot on the
+upper surface, while the under surface is pale lemon yellow without
+marks, but sprinkled more or less with dark atoms. The body is black
+above and white beneath.
+
+[Illustration: FIG. 13.]
+
+The caterpillars of this insect feed on the leaves of cabbage,
+cauliflower, turnip, mignonette, and some other plants.
+
+The female lays her eggs on the under side of the leaves of the food
+plants, generally, but sometimes on the upper sides or even on the
+leaf stalks. They are sugar loaf shaped, flattened at the base, and
+with the apex cut off square at the top, pale lemon yellow in color,
+about one twenty-fifth of an inch long and one fourth as wide, and
+have twelve longitudinal ribs with fine cross lines between them.
+
+The eggs hatch in about a week, and the young caterpillars, which are
+very pale yellow, first eat the shells from which they have escaped,
+and then spin a carpet of silk, upon which they remain except when
+feeding. They now eat small round holes through the leaves, but as
+they grow older change to a greenish color, with a pale yellow line
+along the back, and a row of small yellow spots along the sides, and
+eat their way down into the head of the cabbage.
+
+[Illustration: FIG. 14.]
+
+Having reached its full growth, the caterpillar, Fig. 14, a, which is
+about an inch in length, wanders off to some sheltered place, as under
+a board, fence rail, or even under the edge of clapboards on the side
+of a building, where it spins a button of silk, in which to secure its
+hind legs, then the loop of silk to support the forward part of the
+body.
+
+It now casts its skin, changing to a chrysalis, Fig. 14, b, about
+three-fourths of an inch in length, quite rough and uneven, with
+projecting ridges and angular points on the back, and the head is
+prolonged into a tapering horn. In color they are very variable, some
+are pale green, others are flesh colored or pale ashy gray, and
+sprinkled with numerous black dots. The winter is passed in the
+chrysalis stage.
+
+After the caterpillar changes to a chrysalis, their minute parasites
+frequently bore through the outside and deposit their eggs within.
+These hatch before the time for the butterflies to emerge, and feeding
+on the contents, destroy the life of the chrysalis.
+
+Birds and spiders are of great service in destroying these insects.
+
+The pupæ should be collected and burned if the abdomen is flexible;
+but if the joints of the abdomen are stiff and cannot be easily moved,
+they should be left, as they contain parasites.
+
+Several applications of poisons have been used, the best results being
+obtained from the use of pyrethrum as a powder blown on to the plants
+by a hand bellows, during the hottest part of the day, in the
+proportion of one part to four or five of flour.
+
+As the eggs are laid at different times, any application, to be
+thoroughly tested, must be repeated several times.
+
+
+THE APPLE TREE TENT CATERPILLAR.
+
+_Clisiocampa Americana_ (Harr.)
+
+
+Large, white, silken web-like tents, Fig. 15, are noticed by the
+roadsides, in the early summer, on wild cherry trees, and also on
+fruit trees in orchards, containing numerous caterpillars of a
+blackish color, with fine gray hairs scattered over the body.
+
+This well known pest has been very abundant throughout the State for
+several years past, and the trees in many neglected orchards have been
+greatly injured by it, some being entirely stripped of their leaves.
+The trees in these orchards and the neglected ones by the roadsides
+form excellent breeding places for this insect, and such as are of
+little of no value should be destroyed. If this were well done, and
+all fruit growers in any given region were to destroy all the tents on
+their trees, even for a single season, the work of holding them in
+check or destroying them in the following year would be comparatively
+light.
+
+[Illustration: FIG. 15.]
+
+The moths, Fig. 16, appear in great numbers in July, their wings
+measuring, when expanded, from one and a quarter to one and a half
+inches or more. They are of a reddish brown color, the fore wings
+being tinged with gray on the base and middle, and crossed by two
+oblique whitish stripes.
+
+[Illustration: FIG. 16.]
+
+The females lay their eggs, about three hundred in number, in a belt,
+Fig. 15, c, around the twigs of apple, cherry, and a few other trees,
+the belt being covered by a thick coating of glutinous matter, which
+probably serves as a protection against the cold weather during
+winter.
+
+The following spring, when the buds begin to swell, the egg hatch and
+the young caterpillar seek some fork of a branch, where they rest side
+by side. They are about one-tenth of an inch long, of a blackish
+color, with numerous fine gray hairs on the body. They feed on the
+young and tender leaves, eating on an average two apiece each day.
+Therefore the young of one pair of moths would consume from ten to
+twelve thousand leaves; and it is not uncommon to see from six to
+eight nests or tents on a single tree, from which no less than
+seventy-five thousand leaves would be destroyed--a drain no tree can
+long endure.
+
+As the caterpillars grow, a new and much larger skin is formed
+underneath the old one, which splits along the back and is cast off.
+When fully grown, Fig. 15, a and b, which is in about thirty-five to
+forty days after emerging from the eggs, they are about two inches
+long, with a black head and body, with numerous yellowish hairs on the
+surface, with a white stripe along the middle of the back, and minute
+whitish or yellowish streaks, which are broken and irregular along the
+sides; and there is also a row of transverse, small, pale blue spots
+along each side of the back.
+
+As they move about they form a continuous thread of silk from a fleshy
+tube on the lower side of the mouth, which is connected with the
+silk-producing glands in the interior of the body, and by means of
+this thread they appear to find their way back from the feeding
+grounds. It is also by the combined efforts of all the young from one
+belt of eggs that the tents are formed.
+
+These caterpillars do not feed during damp, cold weather, but take two
+meals a day when it is pleasant.
+
+After reaching their full growth, they leave their tents and scatter
+in all directions, seeking for some protected place where each one
+spins its spindle-shaped cocoon of whitish silk intermingled with
+sulphur colored powder, Fig. 15, d. They remain in these cocoons,
+where they have changed to pupæ, from twenty to twenty-five days,
+after which the moths emerge, pair, and the females lay their eggs for
+another brood.
+
+Several remedies have been suggested, a few of which are given below.
+Search the trees carefully, when they are bare, for clusters of eggs;
+and, when found, cut off the twigs to which they are attached, and
+burn them.
+
+As soon as any tents are observed in the orchard they should be
+destroyed, which may be readily and effectually done by climbing the
+trees, and with the hand protected by a mitten or glove, seize the
+tent and crush it with its entire contents; also swab them down with
+strong soapsuds or other substances; or tear them down with a rounded
+bottle brush.
+
+Burning with a torch not only destroys the caterpillars but injures
+the trees.
+
+It should be observed, however, since the caterpillars, are quite
+regular in taking their meals, in the middle of the forenoon and
+afternoon, that they should be destroyed only in the morning or
+evening, when all are in the tent.
+
+Another remedy is to shower the trees with Paris green in water, in
+the proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE FOREST TENT CATERPILLAR.
+
+_Clisiocampa disstria_ (Hübner.)
+
+
+This species, commonly known as the forest tent caterpillar, closely
+resembles the apple tree tent caterpillar, but does not construct a
+visible tent. It feeds on various species of forest trees, such as
+oak, ash, walnut, hickory, etc., besides being very injurious to apple
+and other fruit trees. The moth, Fig. 17, b, expands an inch and a
+half or more. The general color is brownish yellow, and on the fore
+wings are two oblique brown lines, the space between them being darker
+than the rest of the wing. The eggs, Fig. 17, c and d, which are about
+one twenty fifth of an inch long and one fortieth wide, are arranged,
+three or four hundred in a cluster, around the twigs of the trees,
+Fig. 17, a. These clusters are uniform in diameter and cut off
+squarely at the ends. The eggs are white, and are firmly fastened to
+the twigs and to each other, by a brown substance, like varnish, which
+dries, leaving the eggs with a brownish covering.
+
+[Illustration: FIG. 17.]
+
+The eggs hatch about the time the buds burst, or before, and the young
+caterpillars go for some time without food, but they are hardy and
+have been known to live three weeks with nothing to eat, although the
+weather was very cold.
+
+[Illustration: FIG. 18.]
+
+As soon as hatched they spin a silken thread wherever they go, and
+when older wander about in search for food. The caterpillars are about
+one and a half inches long when fully grown, Fig. 18. The general
+color is pale blue, tinged with greenish low down on the sides, and
+everywhere sprinkled with black dots or points, while along the middle
+of the back is a row of white spots each side of which is an orange
+yellow stripe, and a pale, cream yellow stripe below that. These
+stripes and spots are margined with black. Each segment has two
+elevated black points on the back, from each of which arise four or
+more coarse black hairs. The back is clothed with whitish hairs, the
+head is dark bluish freckled with black dots, and clothed with black
+and fox-colored hairs, and the legs are black, clothed with whitish
+hairs.
+
+At this stage the caterpillars may be seen wandering about on fences,
+trees, and along the roads in search of a suitable place to spin their
+cocoons, which are creamy white, and look very much like those of the
+common tent caterpillar, except that they are more loosely
+constructed.
+
+Within the cocoons, in two or three days they transform to pupæ of a
+reddish brown color, densely clothed with short pale yellowish hairs.
+The moths appear in two or three weeks, soon lay their eggs and then
+die. The insects are not abundant many years in succession, as their
+enemies, the parasites, increase and check them.
+
+Many methods have been suggested for their destruction, but the most
+available and economical are to remove the clusters of eggs whenever
+found, and burn them, and to shower the trees with Paris green in the
+proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE STALK BORER.
+
+_Gortyna nitela_ (Gruen.)
+
+
+The perfect moth, Fig. 19, 1, expands from one to one and a half
+inches. The fore wings are a mouse gray color, tinged with lilac and
+sprinkled with fine yellow dots, and distinguished mainly by a white
+band extending across the outer part. The moths hibernate in the
+perfect state, and in April or May deposit their eggs singly on the
+outside of the plant upon which the young are to feed. As soon as the
+eggs hatch, which is in about a month, the young larvæ, or
+caterpillars, gnaw their way from the outside into the pith.
+
+[Illustration: FIG. 19.]
+
+The plant does not show any sign of decay until the caterpillar is
+fully grown, when it dies. The caterpillar, Fig. 19, 2, is about one
+and one-fourth inches long, of a reddish brown color, with whitish
+stripes along the body. The stripes on the sides are not continuous,
+and the shading of the body varies, being darker on the anterior than
+on the posterior portion. When fully grown, Fig. 20, the color is
+lighter and the stripes are broader. At this stage of life it burrows
+into the ground just beneath the surface, and changes into the pupa
+state. The pupa is three-fourths of an inch long, and of a mahogany
+brown color. The perfect moth appears about the first of September,
+and there is only one brood in a season.
+
+[Illustration: FIG. 20.]
+
+The caterpillars feed in the stalks of corn, tomatoes, potatoes,
+dahlias, asters, and also in young currant bushes, besides feeding on
+many species of weeds. By a close inspection of the plants about the
+beginning of July, the spot where the borer entered, which is
+generally quite a distance from the ground, may be detected, and the
+caterpillar cut out without injury to the plant. This plan is
+impracticable for an extensive crop, but by destroying the borers
+found in the vines that wilt suddenly, one can lessen the number
+another year.
+
+
+THE PYRAMIDAL GRAPEVINE CATERPILLAR.
+
+_Pyrophila pyramidoides_ (Guen.)
+
+
+This caterpillar, Fig. 21, is generally found on grapevines early in
+June, but also feeds on apple, plum, raspberry, maple, poplar, etc. It
+is about an inch and a half in length, with the body tapering toward
+the head; of a whitish green color, darker on the sides; with a
+longitudinal white stripe on the back, broader on the last segments.
+Low down on each side is a bright yellow stripe, between this and the
+one on the back is another less distinct, and the under surface of the
+body is pale green.
+
+[Illustration: FIG. 21.]
+
+The caterpillar is fully grown about the middle or last of June, when
+it descends to the ground, draws together some of the fallen leaves,
+and makes a cocoon, in which it soon changes to a mahogany brown pupa.
+
+[Illustration: FIG. 22.]
+
+In the latter part of July the perfect moth, Fig. 22, emerges,
+measuring, when its wings are expanded, about one and three-fourths
+inches; the fore wings are dark brown shaded with lighter, with dots
+and wavy lines of dull white. The hind wings are reddish, or of a
+bright copper color, shading to brown on the outer angle of the front
+edge of the wing, and paler toward the hinder and inner angle.
+
+The under surface of the wings is lighter than the upper, and the body
+is dark brown, with its posterior portion banded with lines of a paler
+hue.
+
+This pest may be destroyed by hand picking, or by jarring the trees or
+vines on which they are feeding, when they will fall to the ground and
+may be crushed or burned.
+
+
+THE GRAPE BERRY MOTH.
+
+_Eudemis botrana_ (S.V.)
+
+
+The moths emerge and fly early in June, and are quite small,
+measuring, when the wings are expanded, only two-fifths of an inch,
+Fig. 23, a, enlarged. The fore wings are purplish or slate brown from
+the base to the middle, the outer half being irregularly marked with
+dark and light brown.
+
+[Illustration: FIG. 23.]
+
+These insects are two-brooded and the first brood feeds not only on
+the leaves of the grape, but on tulip, sassafras, vernonia and
+raspberry. The caterpillars of the second brood emerge when the grapes
+are nearly grown, and bore in them a winding channel to the pulp,
+continuing to eat the interior of the berry till the pulp is all
+consumed, Fig. 23, d, when, if not full grown, they draw one or two
+other berries close to the first and eat the inside of those.
+
+The mature caterpillar, Fig. 23, b, measures about half an inch in
+length, is dull greenish, with head and thoracic shield somewhat
+darker; the internal organs give the body a reddish tinge. It then
+leaves the grape and forms its cocoon by cutting out a piece of a
+leaf, leaving it hinged on one side; then rolling the cut end over,
+fastens it to the leaf, thus making for itself a cocoon in which to
+pupate. The pupa is dark reddish brown.
+
+The second generation passes the winter in the pupa state, attached to
+leaves which fall to the ground; therefore, if all the dead and dried
+leaves be gathered in the fall and burned, also all the decayed fruit,
+a great many of these insects would be destroyed. As the caterpillars
+feed inside of the berry, no spraying of the vines with poisons would
+reach them. The caterpillar makes a discolored spot where it enters
+the berry, Fig. 23, c. Therefore the infested fruit may be easily
+detected and destroyed.
+
+There is a small parasite that attacks this insect and helps to keep
+it in check. The insect has been known in Europe over a hundred years.
+It is not certain when it was introduced into America, but it is now
+found from Canada to the Gulf of Mexico, and from the Atlantic to the
+Pacific Ocean.
+
+
+THE CODLING MOTH.
+
+_Carpocapsa pomonella_ (Linn.)
+
+
+This well known insect has a world-wide reputation, and is now found
+wherever apples are raised.
+
+[Illustration: FIG. 24.]
+
+The moths are on the wing about the time the young apples are
+beginning to set, and the female lays a single egg in the blossom end
+of each apple. The fore wings of the moths when expanded, Fig. 24, g
+(f, with the wings closed), measure about half an inch across, and are
+marked with alternate wavy, transverse streaks of ashy gray and brown,
+and have on the inner hind angle a large tawny brown, horseshoe shaped
+spot, streaked with light bronze or copper color. The hind wings and
+abdomen are light brown with a luster of satin.
+
+Each female lays about fifty eggs, which are minute, flattened,
+scale-like bodies of a yellowish color. In about a week the eggs hatch
+and the tiny caterpillar begins to eat through the apple to the core,
+Fig. 24, a, pushing its castings out through the hole where it
+entered, Fig. 24, b. Oftentimes these are in sight on the outside in a
+dark colored mass, thus making wormy apples plainly seen at quite a
+distance.
+
+The caterpillar is about two-fifths of an inch in length, of a glossy,
+pale yellowish white color, with a light brown head. The skin is
+transparent and the internal organs give to it a reddish tinge.
+
+When mature the caterpillars, Fig. 24, e, top of head and second
+segment, h, emerge from the apples and seek some sheltered place, such
+as crevices of bark, or corners of the boxes or barrels in which the
+fruit is stored, where they spin a tough whitish cocoon, Fig. 24, i,
+in which they remain unchanged all winter, and transform to pupæ, Fig.
+24, d, the next spring, the perfect moths emerging in time to lay
+their eggs in the new crop of apples.
+
+One good remedy is to gather all the fallen apples, and feed them to
+hogs; another is to let swine and sheep run in the orchard, and eat
+the infested fruit.
+
+It has been recommended to place bands of cloth or hay around the
+trunks of the trees for the caterpillars to spin their cocoons
+beneath, and to remove them at the proper time, and put them in
+scalding water to destroy the worms.
+
+By far the most successful method as yet adopted is to shower the
+apple trees with Paris green in water, one pound to one hundred and
+fifty gallons of water, when the apples are about the size of peas,
+and again in about a week.
+
+
+THE CABBAGE LEAF MINER.
+
+_Plutella cruciferarum_ (Zell.)
+
+
+The cabbage leaf miner is not a native of this country, but was
+imported from Europe.
+
+[Illustration: FIG. 25.]
+
+The perfect moth, Fig. 25, f, with the wings expanded (h, with the
+wings closed, g, a dark variety), measures three-quarters of an inch.
+The fore wings are ashy gray, and on the hinder margin is a white or
+yellowish white stripe having three points extending into the gray,
+thus forming, when the wings are closed, three diamond-shaped white
+spots. Generally there is a dark brown stripe between the white and
+the gray. There are also black dots scattered about on the anterior
+part of these wings.
+
+The hind wings are leaden brown, and the under side of all the wings
+is leaden brown, glossy, and without any dots.
+
+The antennæ are whitish with dark rings, and the abdomen white. There
+are two broods of this insect in this region, the moths of the first
+appearing in May, and those of the second in August. They hibernate in
+the pupa stage.
+
+The caterpillars, Fig. 25, a (b, the top and c, the side of a
+segment), appear in June or July and September; they are small and
+cylindrical, tapering at both ends, pale green, and about one-fourth
+of an inch long. The head has a yellowish tinge, and there are several
+dark stiff hairs scattered over the body.
+
+When ready to transform, this caterpillar spins a delicate gauze-like
+cocoon, Fig. 25, e, made of white, silken threads, on the under side
+of a cabbage leaf. The pupa, Fig. 25, d, and i, the end of a pupa, is
+commonly white, sometimes shaded with reddish brown, and can be
+distinctly seen through the silken case.
+
+The first brood is more injurious than the second, as it feeds on the
+young cabbage leaves before the head is formed, and this must surely
+stunt the growth and make weak, sickly plants; while the second brood
+feeds only on the outside leaves. The caterpillars are very active,
+wriggling violently when disturbed, and falling by a white silken
+thread.
+
+Hot dry weather is favorable to them and enables them to multiply
+rapidly. Advantage has been taken of this fact, and spraying the
+plants thoroughly with water is strongly recommended. Prof. Riley
+states that the insects are very readily destroyed by pyrethrum. There
+are two species of spiders and a species of ichneumon fly that destroy
+them.
+
+
+THE GARTERED PLUME MOTH.
+
+_Oxyptilus periscelidactylus_ (Fitch.)
+
+
+The caterpillars of this species draw together the young grape leaves,
+Fig. 26, a, in the spring, with fine silken threads, and feed on the
+inside, thus doing much damage in proportion to their size. These
+caterpillars, Fig. 26, a, and e, a segment greatly enlarged, are full
+grown in about two weeks, when they are about one-fourth of an inch
+long, pale green with whitish hairs arising from a transverse row of
+warts on each segment.
+
+Early in June they transform to pupæ, Fig. 26, b, which are pale green
+at first and change to dark brown. The surface is rough and the head
+is cut off obliquely, while on the upper side near the middle are two
+sharp pointed horns, Fig. 26, c. They remain in this stage from a week
+to ten days, when the moths emerge.
+
+[Illustration: FIG. 26.]
+
+The moths, Fig. 26, d, belong to the family commonly known as plume
+moths or feather wings (Pterophoridæ), from having their wings divided
+into feather-like lobes. When the wings are expanded they measure
+about seven-tenths of an inch across. They are yellowish brown with a
+metallic luster, and have several dull whitish streaks and spots. The
+fore wings are split down the middle about half way to their base, the
+posterior half having a notch in the outer margin. The body is
+somewhat darker than the wings.
+
+It is not known positively in what stage the winter is passed, but it
+is supposed to be the perfect, or imago stage. The unnatural grouping
+and spinning of the leaves together leads to their detection, and they
+can be easily destroyed by hand picking and then crushing or burning
+them.
+
+       *       *       *       *       *
+
+
+
+
+THE BREEDS OF DOGS.
+
+
+The dog exhibitions that have annually taken place for the last eight
+years at Paris and in the principal cities of France have shown how
+numerous and varied the breeds of dogs now are. It is estimated that
+there are at present, in Europe, about a hundred very distinct and
+very fine breeds (that is to say, such as reproduce their kind with
+constant characters), without counting a host of sub-breeds or
+varieties that a number of breeders are trying to fix.
+
+Most of the breeds of dogs, especially those of modern creation, are
+the work of man, and have been obtained by intercrossing older breeds
+and discarding all the animals that departed from the type sought. But
+many of these breeds are also the result of accident, or rather of
+modifications of certain parts of the organism--of a sort of rachitic
+or teratological degeneration which has become hereditary and has been
+due to domestication; for it is proved that the dog is the most
+anciently domesticated animal, and that its submission to man dates
+back to more than five thousand years. Such is the origin of the
+breeds of terriers, bulldogs, and all of the small house dogs.
+
+Man has often, designedly or undesignedly, aided in the production of
+breeds of this last category by submitting the dog to a regimen
+contrary to nature, or setting to work to reproduce an animal born
+monstrous, either for curiosity or for interest. As well known, the
+accidental characters and the spontaneous modifications which work no
+injury to the essential functions of life became easily hereditary,
+and the same is the case with certain artificial modifications pursued
+for a long series of generations.
+
+It was the opinion of Buffon that the breeds of dogs, which were
+already numerous in his time, were all derived from a single type,
+which, according to him, was the shepherd's dog. Other scientists have
+insisted that the dog descended from the wolf, and others from the
+jackal. At the present time, it is rightly admitted that several
+species of wild dogs have concurred in the formation of the different
+breeds of dogs as we now have them.
+
+In the lacustrine habitations of the stone age in Sweden, and in the
+_kjoekkenmoedding_ (kitchen remains) of Denmark, of the same epoch, we
+find the remains of a dog, which, according to Rutymeyer, belongs to a
+breed which is constant up to its least details, and which is of a
+light and elegant conformation, of medium size, with a spacious and
+rounded cranium and a short, blunt muzzle, and a medium sized jaw, the
+teeth of which form a regular series.
+
+This dog, which has been named by geologists _Canis palustris_, fully
+resembles in size, slenderness of the limbs, and weakness of the
+muscular insertions, the spaniel, the brach hound, or the griffon.
+
+This dog of the stone age is entirely distinct from the wolf and
+jackal, of which some regard the domestic dog as a descendant, and as
+it has appeared in Denmark as well as in Sweden, there is no doubt
+that this species, peculiar to Europe, was subjugated by man and used
+by him, in the first place, for hunting, and later on for guarding
+houses and cattle. Later still, in the age of metals, we observe the
+appearance, both in Denmark and Sweden, of larger and stronger breeds
+of dogs, having in their jaws the character of mastiffs, and probably
+introduced by the first emigrants from Asia.
+
+There are, moreover, historic proofs that the dogs of the strongest
+breeds are indigenous to Asia, where we still find the dog of Thibet,
+the most colossal of all; in fact, in Pliny we read the following
+narrative: Alexander the Great received from a king of Asia a dog of
+huge size. He wished to pit it against bears and wild boars, but the
+dog remained undisturbed and did not even rise, and Alexander had it
+killed. On hearing of this, the royal donor sent a second dog like
+the first, along with word that these dogs did not fight so weak
+animals, but rather the lion and the elephant, and that he had only
+two of such individuals, and in case that Alexander had this one
+killed, too, he would no longer find his equal. Alexander matched this
+dog with a lion and then with an elephant, and he killed them both.
+Alexander was so afflicted at the premature death of the first dog,
+that he built a city and temples in honor of the animal.
+
+Did the mountainous province of Epirus called Molossia, in ancient
+Greece, give its name to the _molossi_ that it produced, or did these
+large dogs give their name to the country? At all events, we know that
+it was from Epirus that the Romans obtained the molossi which fought
+wild animals in the circuses, and that from Rome they were introduced
+into the British islands and have became the present mastiffs.
+
+Although our hunting and shepherd's dogs have a European and the
+mastiffs an Asiatic ancestry, the ancestry of the harriers is African,
+and especially Egyptian; in fact, in Upper Egypt we find a sort of
+large white jackal (_Simenia simensis_) with the form of a harrier,
+and which Paul Gervais regarded with some reason as the progenitor of
+the domestic harrier, and a comparison of their skulls lends support
+to this opinion.
+
+A study of the most ancient monuments of the Pharaohs shows that the
+ancient Egyptians already had at least five breeds of dogs: two very
+slim watch dogs, much resembling the harrier, a genuine harrier, a
+species of brach hound and a sort of terrier with short and straight
+legs. All these dogs had erect ears, except the brach, in which these
+organs were pendent, and this proves that the animal had already
+undergone the effects of domestication to a greater degree than the
+others. The harrier of the time of the Pharaohs still exists in great
+numbers in Kordofan, according to Brehm.
+
+Upon the whole, we here have, then, at least three stocks of very
+distinct dogs: 1, a hunting or shepherd's dog, of European origin; 2,
+a mastiff, typical of the large breed of dogs indigenous to Asia; and
+3, a harrier, indigenous to Africa.
+
+We shall not follow the effects of the combination of these three
+types through the ages, and the formation of the different breeds; for
+that we shall refer our readers to a complete work upon which we have
+been laboring for some years, and two parts of which have already
+appeared.[1]
+
+[Footnote 1: Les Races des Chiens, in La Bibliotheque de l'Eleveur.]
+
+We shall rapidly pass in review the different breeds of dogs that one
+may chance to meet with in our dog shows, beginning with the largest.
+It is again in mountainous countries that the largest dogs are raised,
+and the character common to all of these is a very thick coat. The
+largest of all, according to travelers, is the Thibetan dog. Buffon
+tells of having seen one which, when seated, was five feet in height.
+One brought back by the Prince of Wales from his voyage to the Indies
+was taller in stature, stronger and more stocky than a large mastiff,
+from which it differed, moreover, in its long and somewhat coarse
+hair, which was black on the back and russet beneath, the thighs and
+the tail being clothed with very long and silky hair.
+
+In France, we have a beautiful mountain dog--the dog of the
+Pyrenees--which is from 32 to 34 inches in height at the shoulders,
+and has a very thick white coat, spotted above with pale yellow or
+grayish fox color. It is very powerful, and is capable of
+successfully defending property or flocks against bears and wolves.
+
+The Alpine dog is the type of the mountain dog. It is of the same size
+as the dog of the Pyrenees, and differs therefrom especially in its
+coloring. It is white beneath, with a wide patch of orange red
+covering the back and rump. The head and ears are of the same color,
+with the addition of black on the edges; but the muzzle is white, and
+a stripe of the same color advances upon the forehead nearly up to the
+nape of the neck. The neck also is entirely white. There are two
+varieties of the Alpine or St. Bernard dog, one having long hair and
+the other shorter and very thick hair. We give in Fig. 1 a portrait of
+Cano, a large St. Bernard belonging to Mr. Gaston Leonnard.
+
+[Illustration: FIG. 1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.]
+
+Although this breed originated at the celebrated convent of St.
+Bernard, it no longer exists there in a state of purity, and in order
+to find fine types of it we have to go to special breeders of
+Switzerland and England. The famous Plinnlimon, which was bought for
+$5,000 by an American two or three years ago, and about which there
+was much talk in the papers, even the political ones, was born and
+reared in England. It appears that it is necessary, too, to reduce the
+number of life-saving acts that it is said are daily performed by the
+St. Bernard dogs. This is no longer but a legend. There was, it is
+true, a St. Bernard named Barry, now exhibited in a stuffed state in
+the Berne Museum, which accomplished wonders in the way of saving
+life, but this was an exception, and the reputation of this animal has
+extended to all others of its kind. These latter are simply watch dogs
+kept by the monks for their own safety, and which do not go at all by
+themselves alone to search for travelers that have lost their way in
+the snow.
+
+The Newfoundland dog, which differs from the preceding in its wholly
+black or black and white coat, was, it appears, also of mountain
+origin. According to certain authors, it is indigenous to Norway, and
+was carried to Newfoundland by the Norwegian explorers who discovered
+the island. Adapted to their new existence, they have become excellent
+water dogs, good swimmers, and better life savers by far than the
+majority of their congeners.
+
+Is it from descending to the plain that the mountain dogs have lost
+their long hair and have become short haired dogs like the English dog
+or mastiff and the German or large Danish dogs? It is very probable.
+At all events, it is by this character of having short hair that
+mastiffs are distinguished from the mountain dogs. Again, the large
+breed of dogs are distinguished from each other by the following
+characters: The mastiff is not very high at the shoulders (30 inches),
+but he is very heavy and thick set, with powerful limbs, large head,
+short and wide muzzle and of a yellowish or café-au-lait color
+accompanying a black face; that is to say, the ears, the circumference
+of the eyes and the muzzle are of a very dark color. The German or
+large Danish dogs constitute but one breed, but of three varieties,
+according to the coat: (1) those whose coat is of a uniform color, say
+a slaty gray or isobelline of varying depth, without any white spots;
+(2) those having a fawn colored coat striped transversely with black
+like the zebra, but much less distinctly; (3) those having a spotted
+coat, that is to say, a coat with a white ground strewed with
+irregular black spots of varying size. These, like those of the first
+variety are generally small-eyed. Whatever be the variety to which
+they belong, the German or large Danish dogs are slimmer than, and not
+so heavy as, the mastiffs. Some, even, are so light that it might be
+supposed that they had some heavier blood in their veins. They have
+also a longer muzzle, although square, and are quicker in gait and
+motions.
+
+The largest dogs are to be met with in this breed, and the beautiful
+Danish dog belonging to Prof. Charcot (Fig. 2) is certainly the
+largest dog in France and perhaps in Europe. It measures 36 inches at
+the shoulders and has an osseous and muscular development perfectly in
+keeping with its large stature, and at the same time has admirable
+proportions and lightness, and its motions are comparable to those of
+the finest horse.
+
+[Illustration: FIG. 2--DR. CHARCOT'S LARGE DANISH DOG.]
+
+Among the English dogs or mastiffs, we very frequently meet with
+individuals in which the upper incisors and canines are placed back of
+the corresponding ones in the lower jaw, this being due to a slight
+shortening of the bones of the upper jaw, not visible externally. This
+is the first degree of an artist of teratological development, which,
+since the middle ages, has become very marked in certain subjects, and
+has given rise to a variety in which this defect has become
+hereditary. Such is the origin of the breed of bulldogs. The latter
+were originally as large as the mastiffs. Carried to Spain under
+Philip II., they have there preserved their primitive characters, but
+the bulldogs remaining in England have continued to degenerate, so
+that now the largest are scarcely half the size of the Spanish
+bulldog, and the small ones attain hardly the size of the pug,
+although they preserve considerable width of chest and muscular
+strength.
+
+
+POINTERS.
+
+Man hunted for ages with dogs that he united in a pack; but these
+packs were of a very heterogeneous composition, since they included
+strong dogs, light dogs very swift of foot, shepherds' dogs, and
+others noted for acuteness of scent, and even mongrels due to a
+crossing with the wolf. It is from the promiscuousness of all these
+breeds that has arisen our ordinary modern dog.
+
+The pointer is of relatively recent creation, and is due to the
+falconers. In our western countries, falconry dates from the fourth
+and fifth centuries, as is proved by the capitularies of Dagobert.
+This art, therefore, was not brought to us from the East by the
+crusaders in the twelfth and thirteenth centuries, as stated by Le
+Maout in his Natural History of Birds.
+
+The falconer soon saw the necessity of having a dog of nice scent
+having for its role the finding or hunting up of game without pursuing
+it, in order to permit the falcons themselves to enter into the sport.
+This animal was called the bird dog, and was regarded as coming from
+various countries, especially from Spain, whence the name of spaniel
+that a breed of pointers has preserved. It is quite curious to find
+that for three or four centuries back there have been no spaniels in
+Spain. From Italy also and from southern climes comes what is called
+the _bracco_, whence doubtless is derived the French name _braque_ and
+English brach. Finally the _agasse_ of the Bretons was certainly also
+one of the progenitors of our present pointers. It was, says Oppian, a
+breed of small and very courageous dogs, with long hair, provided with
+strong claws and jaws, that followed hares on the sly under shelter of
+vine-stocks and reeds and sportively brought them back to their
+masters after they had captured them. We have certainly here the
+source of our barbets and griffons.
+
+Finally the net hunters of the middle ages also contributed much to
+the creation of the pointer, for it is to them that we owe the setter.
+It is erroneously, in fact, that certain authors have attributed the
+creation of this dog to hunters with the arquebuse, since this weapon
+did not begin to be utilized in hunting until the sixteenth century.
+Gaston Phoebus, who died in 1391, shows, in his remarkable work, that
+the net hunters made use of Spanish setters and that it was they who
+created the true pointer--the animal that fascinates game by its gaze.
+By the same pull of their draw net they enveloped in its meshes both
+the setter and the prey that it held spellbound.
+
+Upon the whole, we see that at the end of the middle ages there
+existed three types of pointers: spaniels, brachs and very hairy dogs,
+that Charles Estienne, in his Maison Rustique, of the sixteenth
+century, calls barbets. It is again with these three types that are
+connected all the present pointers, which we are going to pass rapidly
+in review.
+
+_The Brach hounds_.--To-day we reserve the name of brachs for all
+pointers with short hair. The type of the old brach still exists in
+Italy, Spain, the south of France and in Germany. It is characterized
+by its large size, its robust form, its large head, its long, flat
+ears, its square muzzle separated from the forehead by a deep
+depression, its large nose, often double (that is to say, with
+nostrils separated by a deep vertical groove), its pendent lips, its
+thick neck, its long and strong paws provided with dew claws, both on
+the fore and the hind feet, and its short hair, which is usually white
+and marked with brown or orange-yellow spots. The old brach breed has
+been modified by the breeders of different countries, either by
+hygiene or by crossing with ordinary dogs, according to the manner of
+hunting, according to taste, and even according to fashion. Thus in
+England, where "time is money" reigns in every thing and where they
+like to hunt quickly and not leisurely, the brach has been rendered
+lighter and swifter of foot and has become the pointer. In France,
+while it has lost a little in size and weight, it has preserved its
+moderate gait and has continued to hunt near its master, "under the
+gun," as they say. The same is the case in Spain, Italy and Germany
+even. In France there are several varieties or sub-breeds of brach
+hounds. The old French brach, which is nothing more than the old type,
+preserved especially in the south, where it is called the Charles the
+Tenth brach, is about twenty-four inches in height, and has a white
+and a maroon coat, which is somewhat coarse. It often has a cleft nose
+and dew-claws on all the feet. The brach of the south scarcely differs
+from the preceding except in color. Its coat has a white ground
+covered with pale orange blotches and spots of the same color. The St.
+Germain brach is finer bred, and appears to be a pointer introduced
+into France in the time of Charles X. It has a very fine skin, very
+fine hair of a white and orange color. The Bourbon brach has the
+characters of the old French brach, with a white coat marked here and
+there with large brown blotches, and the white ground spotted with the
+same color; but what particularly characterizes this dog is that it is
+born with a stumpy tail, as if three-quarters of it had been chopped
+off. The Dupuy brach is slender and has a narrow muzzle, as if it had
+some harrier blood in its veins. It is white, with large dark maroon
+blotches. The Auvergne brach resembles the southern brach, but has a
+white and black coat spotted with black upon white. The pointer, or
+English brach (Fig. 3), descends from the old Spanish brach, but has
+been improved and rendered lighter and much swifter of foot by the
+introduction of the blood of the foxhound into its veins, according to
+the English cynegetic authors themselves. The old pointer was of a
+white and orange color, and was indistinguishable from our St.
+Germain. The pointer now fancied is white and maroon and has a
+stronger frame than the pointer of twenty years ago. The Italian
+brachs are heavy, with lighter varieties, usually white and orange
+color, more rarely _roan_, and provided with dew-claws, this being a
+sign of purity of breed according to Italian fanciers. The German
+brachs are of the type of the old brach, with a stiff white and
+maroon coat, the latter color being so extensively distributed in
+spots on the white as to make the coat very dark.
+
+[Illustration: FIG 3.--POINTER.]
+
+_Spaniels_.--The old type of spaniel has nearly disappeared, yet we
+still find a few families of it in France, especially in Picardy and
+perhaps in a few remote parts of Germany. The old spaniel was of the
+same build as the brach, and differed from it in that the head, while
+being short-haired, was provided with ears clothed with long, wavy
+hair. The same kind of hair also clothed the whole body up to the
+tail, where it constituted a beautiful tuft. The Picard spaniel is a
+little lighter than the old spaniel. It has large maroon blotches upon
+a white ground thickly spotted with maroon, with a touch of flame
+color on the cheeks, over the eyes, and on the legs. The Pont-Andemer
+spaniel is a Norman variety, with very curly hair, almost entirely
+maroon colored, the white parts thickly spotted with a little color as
+in the Picard variety, and a characteristic forelock on the top of the
+head.
+
+[Illustration: FIG 4.--ENGLISH SETTERS.]
+
+In England, the spaniel has given rise to several varieties. In the
+first place there are several sub-breeds of setters, viz.: The English
+setter, still called laverack, which has large black or orange-colored
+blotches on the head, the rest of the body being entirely white, with
+numerous spots of the same color as the markings on the head (Fig. 4);
+the Irish setter, which is entirely of a bright yellowish mahogany
+color; and the Gordon setter, which is entirely black, with orange
+color on the cheeks, under the throat, within and at the extremity of
+the limbs (Fig. 5). Next come the field spaniels, a group of terrier
+spaniels, which includes the Clumber spaniel, which is white and
+orange color; the Sussex spaniel, which is white and maroon; the black
+spaniel, which is wholly black; and the cocker, which is the smallest
+of all, and is entirely black, and white and maroon, or white and
+orange-colored, or tricolored.
+
+[Illustration: FIG 5.--GORDON SETTER.]
+
+_Barbets and Griffons_.--To this latter category belong the dogs, _par
+excellence_, for hunting in swamps. The barbets are entirely covered
+with long curly hair, like the poodles, which are directly derived
+from them. They are white or gray, with large black or brown blotches.
+The griffons differ from the poodles in their coarse and stiff hair,
+which never curls. They have large brown blotches upon a white ground,
+which is much spotted or mixed, as in the color of the hair called
+roan. There is an excellent white and orange-colored variety. The
+griffons, neglected for a long time on account of the infatuation that
+was and is still had for English hunting dogs, are being received
+again with that favor which they have never ceased to be the object of
+in Germany and in Italy (where they bear the name of _spinone_).
+Breeders of merit, such as Mr. Korthals, in Germany, and Mr. E.
+Boulet, in France, are endeavoring to bring them into prominence (Fig.
+6). Finally, we reckon also among hunting dogs some very happy
+crosses between the spaniels and the barbets, which in England are
+called retrievers or water spaniels.--_P. Megnin, in La Nature_.
+
+[Illustration: FIG 6.--COARSE HAIRED GRIFFON.]
+
+       *       *       *       *       *
+
+
+
+
+RESTOCKING THE SEINE WITH FISH.
+
+
+A few days ago, at Bougival, a short distance below the dam of the
+Marly machine, there were put into water 40,000 fry of California
+trout and salmon, designed to restock the Seine, which, in this
+region, has been depopulated by the explosions of dynamite which last
+winter effected the breaking up of the ice jam that formed at this
+place.
+
+[Illustration: RESTOCKING THE SEINE WITH FISH.]
+
+The operation, which is quite simple in itself, attracted a large
+number of inquisitive people by reason of the exceptional publicity
+given to the conflict provoked by a government engineer, who, under
+the pretext that he had not been consulted, made objections to the
+submersion of the little fish. As well known, the affair was
+terminated by a sharp reprimand from Mr. Yves Guyot, addressed to his
+overzealous subordinate.
+
+It would have been a great pity, moreover, if this interesting
+experiment had not taken place, and had not come to corroborate the
+favorable results already obtained.
+
+In three years the California salmon reaches a weight of eleven
+pounds, and, from this time, is capable of reproduction. Its flesh is
+delicious, and comparable to that of the trout, the development of
+which is less rapid, but just as sure.
+
+The fry put into the water on Sunday were but two months old. The
+trout were, on an average, one and a half inches in length, and the
+salmon two and three-quarter inches. They were transported in three
+iron plate vessels, weighing altogether, inclusive of the water, 770
+lb., and provided with air tubes through which, during the voyage, the
+employes, by means of pumps, assured the respiration of the little
+fish.
+
+Our engraving represents the submersion at the moment at which
+the cylinders (of which the temperature has just been taken and
+compared with that of the Seine, in order to prevent too abrupt a
+transition for the fry) are being carefully let down into the
+river.--_L'Illustration_.
+
+       *       *       *       *       *
+
+
+
+
+Figures show that the consumption of iron in general
+construction--other than railroads--in this country has grown from a
+little more than a million and a half of tons in 1879 to more than six
+million tons in 1889. Much of this increase has gone into iron
+buildings. By using huge iron frames and thin curtain walls for each
+story supported thereon, as is done in a building going up on lower
+Broadway, New York city, a good deal of space can be saved.
+
+       *       *       *       *       *
+
+
+
+
+MODERN ARMOR.
+
+By F.R. BRAINARD, U.S.N.
+
+
+The building of a navy, which has been actively going on for the past
+few years, has drawn public attention to naval subjects, and recent
+important experiments with armor plates have attracted large
+attention, hence it may not be amiss to give a description of the
+manufacture and testing of armor. It would be interesting to wade
+through the history of armor, studying each little step in its
+development, but we shall simply take a hasty glance at the past, and
+then devote our attention to modern armor and its immediate future.
+
+Modern armor has arrived at its present state of development through a
+long series of experiments. These experiments have been conducted with
+great care and skill, and have been varied from time to time as the
+improvements in the manufacture of materials have developed, and as
+the physical laws connected with the subject have been better
+understood. There has been very little war experience to draw from,
+and hence about all that is now known has been acquired in peaceful
+experiments.
+
+The fundamental object to be obtained by the use of armor is to keep
+out the enemy's shot, and thus protect from destruction the vulnerable
+things that may be behind it. The first serious effort to do this
+dates with the introduction of iron armor. With this form of armor we
+have had a small amount of war experience. The combat of the Monitor
+and Merrimac, in Hampton Roads, in May, 1862, not only marked an epoch
+in the development of models of fighting ships, but also marked one in
+the use of armor. The Monitor's turret was composed of nine one-inch
+plates of wrought iron, bolted together. Plates built in this manner
+form what is known as laminated armor. (See Fig. 1.) The side armor of
+the hull was composed of four one-inch plates. The Merrimac's casemate
+was composed of four one-inch plates or two two-inch plates backed by
+oak. The later monitors had laminated armor composed of one-inch
+plates. The foregoing, with the Albemarle and Tennessee rams under the
+Confederate flag, are about the sum of our practical experience in the
+use of armor.
+
+[Illustration: Fig. 1.]
+
+European nations took up the subject of armor and energetically
+conducted experiments which have cost large sums of money, but have
+given much valuable data. For a long time wrought iron was the only
+material used for armor, and the resisting power depending on the
+thickness; and the caliber and penetration of guns rapidly increasing,
+it was not long before a point was reached where the requisite
+thickness made the load of armor so great that it was impracticable
+for a ship to carry it. The question then arose as to what were the
+most important parts of a ship to protect. The attempted solutions of
+this question brought out various systems of distributions.
+
+Armored ships were formerly of two classes; in one the guns were
+mounted in broadside, in the other in turrets. Every part of the ship
+was protected with iron to a greater or less thickness. In more modern
+ships the guns are mounted in an armored citadel, in armored barbettes
+or turrets, the engines, boilers and waterline being the only other
+parts protected. There may be said to be three systems of armor
+distribution. The belt system consists in protecting the whole
+waterline by an armored belt, the armor being thickest abreast of the
+engines and boilers. The guns are protected by breastworks, turrets or
+barbettes, the other parts of the ship being unprotected. The French
+use the belt system, and our own monitors may be classed under it. The
+central citadel system consists in armoring that part of the waterline
+which is abreast of the engines and boilers. Forward and aft the
+waterline is unprotected, but a protective deck extends from the
+citadel in each direction, preventing the projectiles from entering
+the compartments below. The hull is divided into numerous compartments
+by water-tight bulkheads, and, having a reserve of flotation, the
+stability of the ship is not lost, even though the parts above the
+protective deck, forward and aft, be destroyed or filled with water.
+The guns are protected by turrets or barbettes. The deflective system
+consists in inclining the armor, or in so placing it that it will be
+difficult or impossible to make a projectile strike normal to the face
+of the plate. A plate that is inclined to the path of a projectile
+will, of course, offer greater resistance to penetration than one
+which is perpendicular; hence, when there is no other condition to
+outweigh this one, the armor is placed in such a manner as to be at
+the smallest possible angle with the probable path of the projectile.
+This system is designed to cause the projectile to glance or deflect
+on impact. Deflective armor should be at such an angle that the
+projectiles fired at it cannot bite, and hence the angle will vary
+according to the projectile most likely to be used. In the usual form
+of deflective deck the armor is at such a small inclination with the
+horizon that it becomes very effective. Turret and barbette armor may
+be considered as deflective armor. The term inclined armor denotes
+deflective armor that is inclined to the vertical. The kinds of armor
+that are in use may be designated as rolled iron, chilled cast iron,
+compound, forged and tempered steel, and nickel steel. Iron armor
+consists of wrought iron plates, rolled or forged, and of cast iron or
+chilled cast iron, as in the Gruson armor. Compound armor consists of
+a forged combination of a steel plate and an iron plate. Steel armor
+consists of wrought steel plates. Nickel-steel armor consists of
+plates made from an alloy of nickel and steel.
+
+I have spoken above of laminated armor. To secure the full benefit of
+this kind, the plates must be neatly fitted to each other; the
+surfaces must make close contact. This requires accurate machining,
+and hence is expensive. To overcome this point sandwiched armor was
+suggested. This consists in placing a layer of wood between the
+laminations, as shown in Fig. 2. It was found that laminated and
+sandwiched armor gave very much less resisting power than solid rolled
+plates of the same thickness. Wrought iron armor is made under the
+hammer or under the rolls, in the ordinary manner of making plates,
+and has been exhaustively studied and experimented with--more so than
+any other form of armor.
+
+[Illustration: Fig. 2.]
+
+Chilled cast iron armor is manufactured by Gruson, in Germany, and is
+used in sea coast defense forts of Europe.
+
+In 1867 several compound plates were made by Chas. Cammell & Co., of
+Sheffield, England, and were tested at Shoeburyness, in England, and
+at Tegel, in Russia. These plates were made by welding slabs of steel
+to iron; but the difficulties were so great that the idea was
+abandoned for the time.
+
+[Illustration: Fig. 3.]
+
+[Illustration: FIG. 4.]
+
+Compound armor, as now manufactured, is of two types: Wilson's patent,
+a backing of rolled iron, faced with Bessemer steel; Ellis' patent, a
+backing of rolled iron, faced with a plate of hard rolled steel,
+cemented with a layer of Bessemer steel. Both these kinds are
+manufactured in England and France in sizes up to fifty tons weight.
+The Wilson process is used at the works of Messrs. Cammell & Co., of
+Sheffield, England, and the Ellis process at the Atlas Works of Sir
+John Brown & Co., of the same place. These are the two leading
+manufacturers of compound plate.
+
+[Illustration: Fig. 5.]
+
+The method employed by Wilson in making compound plate is to first
+make a good wrought iron plate. To the surface of this and along each
+side of the length of the plate are fixed two small channel irons, as
+shown in Fig. 5. The plate is then raised to a welding heat in a gas
+furnace, and transferred to an iron flask or mould. Wedges are driven
+in between the back of the plate and the side of the mould, thus
+forcing the channel irons up snug against the opposite side of the
+mould. Moulding sand is then packed around the back and sides of the
+plate (see Fig. 6). The mould is lowered in a vertical position into a
+pit. Molten steel, manufactured by either the Siemens-Martin or
+Bessemer process, is then poured in through a trough that forms
+several streams, and forms the hard face of the plate. The molten
+steel as it runs down cleans the face of the wrought iron plate,
+scoring it in places, and, being of much higher temperature, the
+excessive heat carbonates the iron to a depth of one-eighth to
+three-sixteenths of an inch, forming a zone of mild steel between the
+hard steel and soft iron. The mould is placed in a vertical position
+to insure closeness of structure and the forcing of gases out of the
+steel. After solidifying, the whole plate is pressed, and passed
+through the rolls to obtain thorough welding. It is then bent, planed,
+fitted, tempered, and annealed to remove internal strains.
+
+[Illustration: Fig. 6.]
+
+In 1887, Wilson took out a patent for improvements in his process of
+making compound plates. In this method of manufacture he takes a
+wrought iron, fibrous plate, fifteen inches thick, built up from a
+number of thin plates. While hot from the forging press, he places
+this plate in an iron mould (see Fig. 7) about 28 inches deep, and
+upon it runs "ingot iron" or very mild steel to a depth of thirteen
+inches. In this form of mould the plate rests on brickwork, and is
+held in place by two grooved side clamps or strips which are caused to
+grip the plate by means of screws which extend through the sides of
+the mould. After solidifying, the plate, which is twenty-eight inches
+thick, is reheated and rolled down to eighteen inches. This is the
+iron backing of the finished plate, and it is again put in the iron
+mould and heated, when a layer of hard steel is run on the exposed
+surface of the original wrought iron plate to a depth of eight inches.
+This makes a plate about twenty-eight inches thick. It is taken from
+the mould, reheated, rolled, hammered or pressed down to twenty
+inches. After cooling, it is bent, planed, and fitted as desired, then
+tempered and annealed to relieve internal strains.
+
+[Illustration: Fig. 7.]
+
+The method employed by Ellis in making compound plates is to take two
+separate plates, one of good wrought iron and one of hard forged
+steel, placing the forged steel plate on the wrought iron plate,
+keeping them separate by a wedge frame or berm of steel around three
+sides, and placing small blocks of steel at various points near the
+middle of the plates (see Fig. 8). These blocks are called distance
+blocks. After covering all the exposed steel surfaces with ganister,
+the plates are put in a gas furnace and heated to a welding heat. They
+are then lowered into a vertical iron pit with the open side
+uppermost. The plates are held in position by hydraulic rams, which
+also prevent bulging. Molten steel of medium softness is then poured
+into the space between the plates, by means of a distributing trough
+having holes in the bottom, and after this has solidified, the whole
+plate is placed under the hydraulic press and reduced about twenty per
+cent. in thickness. The plate is then passed through the rolls, bent,
+planed, fitted, tempered, and annealed to reduce internal strains.
+
+[Illustration: Fig. 8.]
+
+In heating the compound plates for rolling, the plate is placed in the
+furnace with the steel face down, so that the iron part gets well
+heated and the steel does not become too hot. Great care must be taken
+not to overheat the plate, and in working, many passes are given the
+plate with small closings of the rolls. The steel part of a compound
+plate is usually about one third of the full thickness of the plate.
+
+Forged steel armor, tempered in oil, is fabricated at Le Creusot,
+France, by Schneider & Co., using open-hearth steel, and forging under
+the 100 ton hammer. The ingots are cast, with twenty-five per cent.
+sinking head and are cubical in form. The porter bar is attached to a
+lug on one side of the ingot. By means of a crane with a curved jib
+which gives springiness under the hammer, the ingot is thrust into the
+heating furnace. On arriving at a good forging heat it is swung around
+to the 100 ton hammer, under which it is worked down to the required
+shape. A seventy-five ton ingot requires about eight reheatings before
+being reduced to shape. Having been reduced to shape, the plate is
+carefully annealed, then raised to a high tempering heat, and the face
+tempered in oil. It is reannealed to take out the internal strains,
+care being taken not to reduce the face hardness more than necessary.
+The Schneider process of tempering is based upon the utilization of
+the absorption of heat caused by the fusing or melting of a solid
+substance, and of the fact that so long as a solid is melting or
+dissolving in a liquid substance, the liquid cannot get appreciably
+hotter, except locally around the heating surface. The body to be
+hardened is plunged at the requisite temperature into a bath
+containing the solid melting body, or is kept under pressure in the
+solid material of low melting point until the required extraction of
+heat has taken place, more solid material being added if necessary as
+that originally present melts and dissolves.
+
+Nickel steel armor is made in a similar manner to the steel plates,
+the material used in casting the ingot being an alloy of nickel and
+steel containing between three and four per cent. of nickel.
+
+The Harvey process of making armor consists in taking an all-steel
+plate and carbonizing the face. This carbonizing process is very
+similar to the cementation process of producing steel, and by it the
+face of the plate is made high in carbon and very hard.
+
+The system invented by Sir Joseph Whitworth, of Manchester, England,
+consists in what might be called scale armor. A section of a sample of
+the armor represents four plates. The outer layer, one inch thick, is
+composed of steel of a tensile strength of 80 tons per square inch;
+the second layer, one inch thick, of steel whose tensile strength is
+40 tons per square inch; the third and fourth layers, each one-half
+inch thickness, of mild steel. The outer layer is in small squares of
+about ten inches on a side, and is fastened to the second layer by
+bolts at the corners and one in the middle of each square. The surface
+is flush. (See Fig. 9.) The end sought by the above system is to break
+up the shot by the hard steel face and to restrict any starring or
+cracking of the metal to the limit of the squares or scales struck.
+The bolts are of high carbon and are extremely hard steel.
+
+[Illustration: Fig. 9.]
+
+Armor plates must often be bent or curved to single or double
+curvature and sometimes to a warped surface to fit the form of the
+ship. There are several methods of bending plates. One method employs
+a cast iron slab of the required form, which is placed on the piston
+of a hydraulic press. The armor plate is placed face down on this
+slab, and on top of the plate are laid packing blocks of cast iron, of
+such sizes and shapes as to conform to the required curve. These
+blocks take against the upper table of the press, when the piston is
+forced up, and the hot plate is thus dished to the proper form.
+
+In the French method of bending, an anvil or bed plate of the required
+curve is used, and the armor plate is forced to take the curve by
+being hammered all over its upper surface with a specially designed
+steam hammer.
+
+The edges of the plate are trimmed by large, powerful slotting
+machines or circular saws; the latter, however, operate in exactly the
+same manner as a slotter, except that there is no return motion to the
+tool. Each tooth of the saw is but a slotting tool, and these teeth
+are, by screws, rendered capable of being nicely adjusted in the
+circumference of the saw.
+
+The plates are fastened to the hulls and backing by heavy bolts,
+varying in size according to the weight of the individual plate. For
+the 6,000 ton armored ships, these bolts are from 2.75 to 3.1 inches
+in diameter and from 18.45 to 23 inches in length. They are tapped two
+or three inches into the armor and do not go through the plate. They
+pass through wrought iron tubes in the backing and set up with cups,
+washers and nuts against the inner skin of the ship.
+
+At steel works where plates for our new navy are being manufactured,
+there are inspectors who look after the government's interests.
+Officers of the navy are detailed for this work, and their duty is to
+watch the manufacture of plates through each part of the process and
+to see that the conditions of the specifications and contract are
+complied with.
+
+The inspection and testing of armor plates consists in examining them
+for pits, scales, laminations, forging cracks, etc., in determining
+the chemical analysis of specimens taken from different parts, in
+determining the physical qualities of specimens taken longitudinally
+and transversely, and the ballistic test. Specifications for these
+different tests are constantly undergoing change, and it would be
+impossible to state, with exactness, what the requirements are or will
+be in the near future. The ballistic test is the important one, and is
+made by taking one plate of a group and subjecting it to the fire of a
+suitable gun. The other tests are simply to insure, as far as
+practicable, that all the other plates of the group are similar to and
+are capable of standing as severe a ballistic test as the test plate.
+
+The following will give an idea of the ballistic test as prescribed by
+the Bureau of Ordnance, Navy Department. The test plate, irrespective
+of its thickness, is to be backed by thirty-six inches of oak or other
+substantial wood. Near the middle region of the plate an equilateral
+triangle will be marked, each side of which will be three and one-half
+calibers long. The lower side of the triangle will be horizontal.
+Three shots will be fired, the points of impact being as near as
+possible the extremities of the triangle. The velocity of the shot
+will be such as to give the projectile sufficient energy to just pass
+through a wrought iron plate of equal thickness to the test plate, and
+through its wood backing. The velocity is calculated by the Gavre
+formula:
+
+              a
+       V² =  --- { 3507 E² × 2265464 e^{1.4} }
+              w
+
+[TEX: V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}]
+
+  V = the velocity of the projectile in feet per second.
+  a = the diameter of the projectile in inches.
+  w = the weight of the projectile in pounds.
+  E = the thickness of the backing in inches.
+  e = the thickness of the plate in inches.
+
+Using the above formula we can make out a table as follows:
+
+-------+-------+-------------+-------+-------+------+---------+
+Plate. |Backi'g| Gun, service|  w,   |  a,   |  V.  | Energy, |
+Inches.|Inches.| shot.       |Pounds.|Inches.| f. 8.| Impact. |
+       |       |             |       |       |      | f. tons.|
+-------+-------+-------------+-------+-------+------+---------+
+  6    |  36   |   6" B.L.R. |  100  |  5.96 | 1389 |  1337   |
+  7    |  36   |   6"   "    |  100  |  5.96 | 1528 |  1619   |
+  8    |  36   |   8"   "    |  250  |  7.96 | 1213 |  2550   |
+  9    |  36   |   8"   "    |  250  |  7.96 | 1308 |  2966   |
+ 10    |  36   |   8"   "    |  250  |  7.96 | 1399 |  3390   |
+ 11    |  36   |   8"   "    |  250  |  7.96 | 1489 |  3839   |
+ 12    |  36   |  10"   "    |  500  |  9.96 | 1247 |  5386   |
+ 13    |  36   |  10"   "    |  500  |  9.96 | 1315 |  5987   |
+ 14    |  36   |  10"   "    |  500  |  9.96 | 1381 |  6608   |
+ 15    |  36   |  12"   "    |  850  | 11.96 | 1215 |  8699   |
+ 16    |  36   |  12"   "    |  850  | 11.96 | 1269 |  9710   |
+ 17    |  36   |  12"   "    |  850  | 11.96 | 1332 | 10454   |
+ 18    |  36   |  12"   "    |  850  | 11.96 | 1374 | 11124   |
+ 19    |  36   |  12"   "    |  850  | 11.96 | 1425 | 11965   |
+ 20    |  36   |  12"   "    |  850  | 11.96 | 1476 | 12837   |
+-------+-------+-------------+-------+-------+------+---------+
+
+
+No projectile or fragment of the plate or projectile must get wholly
+through the plate and backing. The plate must not break up or give
+such cracks as to expose the backing, previous to the third shot.
+
+The penetration of projectiles of different forms into various styles
+of armor has been very thoroughly studied and many attempts have been
+made to bring the subject down to mathematical formulæ. These formulæ
+are based on several suppositions, and agree very closely with results
+obtained in actual experiments, but there are so many varying
+conditions that it is extremely doubtful if any formulæ will ever be
+written that will properly express the penetration.
+
+Many different forms have been given to the heads of projectiles, as
+flat, ogival, hemispherical, conoidal, parabolic, blunt trifaced, etc.
+
+The flat headed projectile has the shape of a right cylinder, and acts
+like a punch, driving the material of the armor plate in front of it.
+These projectiles are especially valuable when firing at oblique
+armor, for they will bite or cut into the armor when striking at an
+angle of thirty degrees.
+
+The ogival head acts more as a wedge, pushing the metal aside, and
+generally will give more penetration in thick solid plates than the
+flat headed projectile. The ogival head is usually designed by using a
+radius of two calibers.
+
+The hemispherical, conoidal, parabolic and blunt trifaced all give
+more or less of the wedging effect. The blunt trifaced has all the
+good qualities of the ogival of two calibers. It bites at a slightly
+less angle, and the three faces start cracks radiating from the point
+of impact.
+
+Forged steel is the best material for armor-piercing projectiles, but
+many are made of chilled cast iron, on account of its great hardness
+and cheapness.
+
+The best weight for a projectile is found by the formula
+
+    w = d³ (0.45 to 0.5)
+
+w being the weight in pounds, d the diameter in inches and 0.45 to 0.5
+having been determined by experiment.
+
+With a light projectile we get a flat trajectory, and accuracy at
+short ranges is increased. With a heavy projectile the resistance of
+the air has less effect and the projectile is advantageously employed
+at long ranges.
+
+In the following formulæ, used in calculating the penetration of
+projectiles in rolled iron armor,
+
+  g = the force of gravity.
+  w = the weight of projectile in pounds.
+  d = the diameter of projectile in inches.
+  v = the striking velocity in feet per second.
+  P = the penetration in inches.
+
+
+Major Noble, R.A., gives
+
+              _________________
+         1.6 /      w v²
+   P =  /\  /  ----------------
+          \/   [pi] g d 11334.4
+
+[TEX: P = \sqrt[1.6]{\frac{w \ v^2}{\pi \  g \  d \ 11334.4}}]
+
+U.S. Naval Ordnance Proving Ground uses
+
+              ________________
+        2.035/      w v²
+   P =  /\  /  ---------------
+          \/   [pi] g d 3852.8
+
+[TEX: P = \sqrt[2.035]{\frac{w \ v^2}{\pi \  g \  d \ 3852.8}}]
+
+Col. Maitland gives
+
+            w v²
+   P =  ------------
+        g d² 16654.4
+
+[TEX: P = \frac{w \ v^2}{g \  d^2 \ 16654.4}]
+
+Maitland's latest formula, now used in England, is
+
+                 _
+          v     /w
+    P = ----- \/ - - 0.14 d
+        608.3    d
+
+[TEX: P = \frac{v}{608.3} \sqrt{\frac{w}{d}} - 0.14 \ d]
+
+General Froloff, Russian army, gives
+
+         w v
+    P = ------
+        d² 576
+
+[TEX: P = \frac{w \ v}{d^2 \ 576}]
+
+for plates less than two and one-half inches thick, and
+
+         w v
+    P = ------ - 1.5
+        d² 400
+
+[TEX: P = \frac{w \ v}{d^2 \ 400} - 1.5]
+
+for plates more than two and one-half inches thick.
+
+
+If [theta] be the angle between the path of the projectile and the
+face of the plate, then v in the above formulæ becomes v sin [theta].
+
+When we come to back the plates, their power to resist penetration
+becomes greater, and our formula changes. The Gavre formula, given
+above, is used to determine the velocity necessary for a projectile to
+pass entirely through an iron plate and its wood backing.
+
+Compound and steel armor are said to give about 29 per cent. more
+resisting power than wrought iron, but in one experiment at the
+proving ground, at Annapolis, a compound plate gave over 50 per cent.
+more resisting power than wrought iron.
+
+The Italian government, after most expensive and elaborate comparative
+tests, has decided in favor of the Creusot or Schneider all-steel
+plates, and has established a plant for their manufacture at Terni,
+near Rome.
+
+The French use both steel and compound plates; the Russians, compound;
+the Germans, compound; the Swedes and Danes use both. Spain has
+adopted and accepted the Creusot plate for its new formidable armored
+vessel, the Pelayo; and China too has recently become a purchaser of
+Creusot plates.
+
+Certain general rules may be laid down for attacking armor. If the
+armor is iron, it is useless to attack with projectiles having less
+than 1,000 feet striking velocity for each caliber in thickness of
+plate. It is unadvisable to fire steel or chilled iron filled shells
+at thick armor, unless a normal hit can be made. When perforation is
+to be attempted, steel-forged armor-piercing shells, unfilled, should
+be used. They may be filled if the guns are of great power as compared
+to the armor. Steel and compound armor are not likely to be pierced by
+a single blow, but continued hammering may break up the plate, and
+that with comparatively low-powered guns.
+
+Wrought iron must be perforated, and hard armor, compound or steel,
+must be broken up. Against wrought iron plates the projectile may be
+made of chilled cast iron, but hard armor exacts for its penetration
+or destruction the use of steel, forged and tempered. Against
+unarmored ships, and against unarmored portions of ironclads, the
+value of rapid-firing guns, especially those of large caliber, can
+hardly be overestimated.
+
+The relative value of steel and compound armor is much debated, and at
+present the rivalry is great, but the weight of evidence and opinion
+seems to favor the all-steel plate. The hard face of a compound plate
+is supposed to break up the projectile, that is, make the projectile
+expend its energy on itself rather than upon the plate, and the
+backing of wrought iron is, by its greater ductility, to prevent the
+destruction of the plate. It seems probable that these two systems
+will approach each other as the development goes on. An alloy of
+nickel and steel is now attracting attention and bids fair to give
+very good results.
+
+The problem to be solved, as far as naval armor is concerned, is to
+get the greatest amount of protection with the least possible weight
+and volume, and this reduction of weight and volume must be
+accomplished, in the main, by reducing the thickness of the plates by
+increasing the resisting power of the material. In the compound plate
+great surface hardness is readily and safely attained, but it has not
+yet been definitely determined what the proper proportionate thickness
+of iron and steel is.
+
+A considerable thickness of steel is necessary to aid, by its
+stiffness, in preventing the very ductile iron from giving back to
+such an extent as to distort the steel face and thus tear or separate
+the parts of the plate. The ductile iron gives a very low resisting
+power, its duty being to hold the steel face up to its work. If now we
+substitute a soft steel plate in the place of the ductile iron, we
+will get greater resisting power, but our compound plate then becomes
+virtually an all-steel one, only differing in process of manufacture.
+The greatest faults of the compound plate are the imperfect welding of
+the parts and the lack of solidity of the iron. When fired at, the
+surface has a tendency to chip.
+
+In the all-steel plate we have the greatest resisting power
+throughout, but there are manufacturing difficulties, and surface
+hardness equal to that of the compound plate has not been obtained.
+The manufacturing difficulties are being gradually overcome, and
+artillerists are in high hopes that the requisite surface hardness
+will soon be obtained.
+
+The following may be stated as well proved:
+
+1. That steel armor promises to replace both iron and compound.
+
+2. That projectiles designed for the piercing of hard armor must be
+made of steel.
+
+3. That the larger the plate, the better it is able to absorb the
+energy of impact without injury to itself.
+
+4. That the backing must be as rigid as possible.
+
+       *       *       *       *       *
+
+[FROM ENGINEERING.]
+
+
+
+
+THE COMPRESSED AIR SYSTEM OF PARIS.
+
+
+The demand for compressed air as a motive power is constantly
+increasing in Paris; the company, according to its official reports,
+is financially prosperous, and it seems difficult to understand how it
+should continue as an actively going concern, unless it at all events
+paid its way. The central station of St. Fargeau, originally started
+on modest lines, for maintaining a uniform time by pneumatic pressure
+throughout Paris, has grown rapidly to very large proportions, though
+it has never been able to supply the demand made on it for power; and
+at the present time a second and still larger station is being
+constructed in another part of Paris. We confess that we do not
+understand why such large sums of money should continue to be spent if
+the enterprise is not commercially a sound one, nor how men of such
+eminence in the scientific world as Professor Riedler should, without
+hesitation, risk their reputation on the correctness of the system, if
+it were the idle dream of an enthusiast, as many persons--chiefly
+those interested in electric transmission--have declared it to be.
+
+[Illustration: Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION]
+
+In describing the developments that have taken place during the last
+two years, we shall confine ourselves entirely to the details of a
+report recently made on the subject by Professor Riedler. As soon as
+it became evident that a very largely increased installation was
+necessary, it was determined that the new central station should be as
+free as possible from the defects of the first one. These defects,
+which were the natural results of the somewhat hasty development of an
+experimental system, were of several kinds. In the first place, so
+large a growth had not been contemplated, and the extensions were
+made more or less piecemeal, instead of being on a regular plan; the
+location of the central station itself was very unfavorable, both as
+regards the facilities for obtaining coal and other supplies; the cost
+of water was excessive, and the amount available, inadequate.
+
+This evil was partly remedied by elaborate arrangements for cooling
+the injection water so that it could be repeatedly used, a device
+costly and ineffective, and resulting in extravagant working, to say
+nothing of the high charges made by the Paris company for supplying
+water. To these drawbacks had to be added others of an even more
+serious character. The engines first laid down were not economical,
+and the compressors employed gave but a very inferior result; with
+each extension of the plant, the efficiency of both engines and
+compressors was increased, the most satisfactory, we believe, having
+been those supplied by the Societe Cockerill, and one of which was
+exhibited at the Paris exhibition in 1889. Still it was clearly
+recognized that much better results were possible, results which
+Professor Riedler claims have been attained and which will be embodied
+in the new installation now in progress.
+
+This central station is located on the left bank of the Seine, close
+to the fortifications, opposite Vincennes and not far from the
+terminal stations of the Orleans and the Paris, Lyons, and
+Mediterranean Railways; the plan, Fig. 1, shows the position. The
+works are separated from the river by the quay, over which a bridge
+will be constructed for the transfer of coal from the landing stages
+belonging to the company, into the works; as will be readily seen from
+the plan, it would be quite easy to run junction lines to the two
+adjacent railways, but with all the advantages given by water
+carriage, it was considered unnecessary to incur the expense. The
+river also affords a constant and unlimited water supply, so that none
+of the difficulties existing at St. Fargeau Station in imperfect
+condensation and cooling will be met with.
+
+The new installation, called the Central Station of the Quai de la
+Gare, is laid out on a very large scale, the total generating energy
+provided for being no less than 24,000 horse power; of this it is
+intended that 8,000 horse power will be in operation this year, and an
+extension of 10,000 horsepower in 1892; the power now in course of
+completion comprises four engines of 2,000 horse power each. Four
+batteries of boilers will provide steam for these engines. Figs. 2, 3,
+and 4 show the first section of the installation now in progress; the
+four groups of engines (three-cylinder condensing) are shown at 1, 2,
+3, and 4; the four groups of boilers ranged behind them at F, F; the
+feed water heaters belonging to each group at V V.
+
+[Illustration: COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS.
+(FIG. 2,3,4)]
+
+The end of the building abuts against the Seine, and the position of
+the water conduits for inlet and discharge are indicated at C and A
+respectively. The installation, when completed, will include very
+extensive arrangements for transporting and storing coal, and the
+interior of the boiler houses will be furnished with an overhead
+system of rails and carriers for handling the coal automatically, as
+far as possible. All the principal mains and steam pipes are made in
+duplicate, not only for greater security, but in order that each set
+of engines and boilers may be connected interchangeably without delay.
+The Seine supplies an ample quantity of water, but not in a condition
+either for feeding the boilers, for condensation, or for the air
+compressors.
+
+[Illustration: THE NEW COMPRESSED AIR STATION AT PARIS. (FIG. 5, 6)]
+
+Special provisions have therefore to be made to filter the water
+efficiently before it is used. For this purpose the water is led to a
+group of four filters (see L, Fig. 4); from them it passes into the
+tanks, JJ, and is pumped into the heaters. The filters can be rapidly
+and automatically cleaned by reversing the flow of water through them.
+Figs. 5 and 6 show the general form of the type of engine adopted, as
+well as the engine house, some of the mains, etc. They are vertical
+triple-expansion engines, and are being constructed by MM. Schneider
+et Cie, of Creusot, with a guarantee of coal consumption not to exceed
+1.54 lb. per horse power per hour, with a penalty of 2,000 francs for
+every 100 grammes in excess of this limit. It is evident that with
+this restricted fuel consumption, a large margin for economy will
+exist at the new works, as compared with the St. Fargeau station,
+where the best engines cannot show anything like this result, while
+some of the earlier ones are distinctly extravagant, and the whole
+installation is handicapped with imperfect means of condensation.
+
+Moreover, according to Professor Riedler, the consumption of steam by
+the new Schneider engines will be only 5.3 kilos. per horse power and
+per hour as compared with some of the large engines requiring 9
+kilos., and the Cockerill engines--using 8 kilos. per hour, not to
+speak of the older motors that are very extravagant in the use of
+steam. The St. Fargeau station is worked under a further disadvantage.
+The constantly increasing demand from subscribers taxes the resources
+of the station to their fullest extent, so that practically there is
+no reserve power.
+
+In the new installation the work will be equally constant, but care
+will be taken always to have a sufficient reserve. Electric lighting
+will form a considerable part of the duty to be done from this
+station, and in all cases it is intended to work with accumulators, so
+that the resistance to be overcome by the engines, so far as this part
+of the duty is concerned, will be well known and uniform. The
+engineers of the Compressed Air Co., of Paris, have during the last
+five years acquired an experience which could only be attained at a
+high price and at the expense of a certain amount of failure; this
+period, it is claimed, is now passed, and in the new installation it
+is possible to put into practice all the valuable lessons learned at
+St. Fargeau, to say nothing of the more favorable natural conditions
+under which the extension is being started and the improvements in the
+compression of the air made by Mr. Popp and Professor Riedler, and to
+which we shall refer later.
+
+Chiefly in consequence of the high value of the ground, vertical
+engines were adopted at the new station; the proximity to the river
+made the foundations somewhat costly, and the risk of occasional
+floods rendered it desirable to set the level of the engine bedplates
+20 inches above the floor of the building; the foundations of the
+engines are continuous, but are quite independent of the building.
+There are three compressing cylinders in each set of engines, one
+being above each steam cylinder. Two of these are employed to compress
+the air to about 30 lb. per square inch, after which it passes into a
+receiver and is cooled; it is then admitted into the third or final
+compressing cylinder and raised to the working pressure at which it
+flows into the mains. In the illustrations, h, m, and b are the high,
+intermediate, and low pressure cylinders of one set of engines; as
+will be seen, each cylinder is on a separate frame connected by
+girders; directly above the cylinders are the two low and the one high
+pressure air cylinders, b¹, m¹, and h¹ respectively. The former
+deliver the air compressed to the first stage into the receiver, T¹
+(see Fig. 5), whence it passes into the third compression cylinder,
+and thence by a main into the cylinders, R R, which are in direct
+communication with the delivery mains; these mains terminate in the
+subway, T. The water for condensation is brought into the engine house
+by the channel, C, and the condenser pumps, a, draw direct from this
+supply; the discharge main back to the river is shown at A. The
+relative positions of the engine and boiler houses are indicated in
+Figs. 2 to 5, where F shows the end of one group of boilers; the air
+supply for the compressors is led from the central raised portion, S,
+of the roof.
+
+Professor Riedler's first experiments in improving the efficiency of
+air compressors were made with one of the Cockerill compressors in use
+at the St. Fargeau Station, and considerable difficulty attended this
+work, because the machinery was necessarily kept almost in constant
+operation. These compressors were designed by MM. Dubois and Francois,
+of Seraing. Two of their leading features were the delivery of the
+compressed air at as low a temperature as possible, and with a
+relatively high piston speed of about 400 ft. a minute. The former
+object is attained by the injection of a very fine water spray at each
+end of the air cylinder, and its rapid removal with each stroke; the
+free as well as the compressed air flows through the same passages,
+one at each end of the cylinder; the inlet valves being placed at the
+side of these passages, and the outlet or compressed air valves at the
+top, the compressed air, entering a chamber above the cylinder, common
+to both valves, and passing thence to the reservoir. The compressed
+air valves, which are seven in. in diameter, are brought back sharply
+to their seats at each stroke, by a small piston operated by
+compressed air flowing through a by-pass from the chamber. The
+illustrations published by us on page 686 of our forty-seventh volume
+show the construction of these compressors. The engravings on page 683
+of the same volume illustrate the compressors used in a somewhat older
+part of the installation; they were made by M. Blanchod, of Vevey, and
+a passing reference may be made to them. The air is admitted through
+valves in the cylinder, and is forced out through spring-loaded
+valves; water is admitted into the cylinder to cool the air.
+
+Fig. 7 indicates the modification made by Professor Riedler in one of
+the Cockerill compressors: a receiver, A, was placed under the two
+compressing cylinders, B and C. The first stage is completed in the
+large cylinder, B, the air being compressed to about 30 lb. per square
+inch; from this it is discharged into the receiver, A, through the
+pipe, B¹, where it meets with a spray injection that cools it to the
+temperature of the water. The final stage is then effected in the
+smaller cylinder, C, which, drawing the air from the receiver through
+the pipe, C¹, compresses it to about 90 lb. and delivers it through
+the pipe, d, to the mains. We hope shortly to publish drawings of this
+compressor in its final form; in its elementary stage Professor
+Riedler claims to have obtained some very remarkable results. He says
+that the waste spaces in his modification were much smaller than in
+the Cockerill compressor, while the efficiency of the apparatus was
+largely increased. The actual engine duty per horse power and per hour
+was raised, as a maximum, to 384 cubic feet of air at atmospheric
+pressure, and compressed to 90 lb. per square inch, a marked increase
+on the duty of the compressors in use at the St. Fargeau station. The
+Cockerill compressors experimented on at the same time showed a
+maximum duty of 306 cubic feet of air. A considerable advantage is
+claimed in drawing clean and cool air from the outside of the
+building, and beyond the main feature of carrying out the compression
+in two stages, Mr. Riedler appears to have shown great skill in
+introducing several minor alterations and improvements in the plant.
+
+[Illustration: EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig.
+8, 9, 10)]
+
+Figs. 8, 9 and 10 are diagrams showing the comparative efficiency of
+the three types of compressors at St. Fargeau--Fig. 10 being a diagram
+of the Riedler compressor--and indicate the gain derived from the
+intermediate cooling. The loss is shown to be only 12 per cent., as
+compared with a loss of 43 per cent. in a large part of the plant, and
+of 105 per cent. in the earlier compressors of the St. Gothard type.
+The table given herewith contains a summary of trials made by
+Professor Gutermuth, and are intended to show the comparative results
+of an extended trial with three kinds of compressors at St. Fargeau.
+
+  PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
+
+--------------+-------+--------+------+-------+--------+--------+---------+
+              | R   p |        |  E   |       |        |        |         |
+              | e o e | Horse- |  f   |Amount |Quantity| Cubic  |         |
+Compressors.  | v f r | Power  |  f   |of Air | of Air |Feet of |Final Air|
+              | o     |Absorbed|  i   |Passing| Passing|Air per |Pressure.|
+              | l E m |   by   |  c   |through| through| Horse- |         |
+              | u n i |Compres-|  i   | Inlet | Valves | Power  |         |
+              | t g n | sors.  |  e   | Valves| per    | and per|         |
+              | i i u |        |  n   | each  | Hour.  |  Hour. |         |
+              | o n t |        |  c   |Revolu-|        |        |         |
+              | n e e |        |  y   | tion. |        |        |         |
+              | s   . |        |  .   |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+              |       |        |      | cubic |  cubic |        |lb. per  |
+1.            |       |        |      | feet  |  feet  |        |sq. in.  |
+_Sturgeon_    |       |        |      |       |        |        |         |
+_Compressor_  |  37   |   302  | .87  | 41.67 |  91,507| 261.3  | 90      |
+Diameter of   |  37   |   258  | .87  | 38.13 |  84,650| 276.1  | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+23.62 in.     |       |        |      |       |        |        |         |
+and 21.66 in.;|       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+48.63 in.     |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+2.            |       |        |      |       |        |        |         |
+_Cockerill_   | 40    |   337  | .83  | 46.61 | 111,864| 281.83 | 90      |
+_Compressor._ | 45    |   353  | .83  | 46.61 | 125,844| 302.66 | 90      |
+Diameter of   | 40    |   342  | .88  | 49.43 | 118,632| 296.65 | 90      |
+cylinder,     | 46    |   377  | .85  | 48.02 | 132,534| 298.77 | 90      |
+25.98 in.;    | 38.67 |   324  | .89  | 50.14 | 116,434| 306.19 | 90      |
+stroke,       | 38.5  |   337  | .89  | 50.14 | 115,818| 294.18 | 90      |
+47.24 in.     | 38.6  |   329  | .91  | 50.84 | 117,740| 305.13 | 90      |
+              |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+3.            |       |        |      |       |        |        |         |
+_Riedler_     | 52    |   615  | .985 | 77.34 | 241,300| 353.50 | 90      |
+_Compressor._ | 60    |   709  | .985 | 76.98 | 277,128| 353.50 | 90      |
+Diameter of   | 38    |   422  | .985 | 77.34 | 176,330| 376.12 | 90      |
+low-pressure  | 39    |   424  | .985 | 77.34 | 181,030| 384.60 | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+42.91 in.;    |       |        |      |       |        |        |         |
+diameter of   |       |        |      |       |        |        |         |
+high-pressure |       |        |      |       |        |        |         |
+cylinder,     |       |        |      |       |        |        |         |
+26.38 in.;    |       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+47.24 in.     |       |        |      |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+
+
+The results thus obtained were so satisfactory that the designs were
+prepared for the great compressors to be operated at the new central
+station on the Quai de la Gare by the 2,000 horse power engines.
+
+The transmission of the compressed air through the mains is
+unavoidably attended with a certain percentage of loss, which, of
+course, increases with the length of the transmission, the presence of
+leakage at the joints, etc. Professor Riedler has devoted considerable
+time to the investigation of this source of waste, and we shall
+presently refer to the results he has recorded; in the first place,
+however, we propose to consider what he has to say on the subject of
+utilizing the air at the points of delivery, and the means employed
+for obtaining a relatively high efficiency of the motor.
+
+In the earliest stages of the Popp system in Paris it was recognized
+that no good results could be obtained if the air were allowed to
+expand direct into the motor; not only did the formation of ice due to
+the expansion of the air rapidly accumulate and choke the exhaust, but
+the percentage of useful work obtained, compared with that put into
+the air at the central station, was so small as to render commercial
+results hopeless. The practice of heating the air before admitting it
+to the motor is quite old, but until a few years ago it never seems to
+have been properly carried out; in several mining installations where
+this motive power had been long used, more or less imperfect attempts
+had been made to heat the air; in one instance only, recorded by
+Professor Riedler, was an efficient means employed. In this case a
+spray of boiling water was injected into the cylinder and mixed with
+the air at each stroke, with the result that a very marked economy was
+obtained.
+
+After a number of experiments, Mr. Popp arrived at the conclusion that
+the simplest mode of heating, if not the most efficient, was at all
+events the most suitable, as it was a matter of the first importance
+that subscribers should not be troubled with the charge of any
+apparatus involving complication or careful management; he therefore
+adopted a simple form of cast iron stove lined with fireclay, heated
+either by a gas jet or by a small coke fire. It was found that this
+apparatus, crude as it was, answered the desired purpose, until some
+better arrangement was perfected, and the type was accordingly adopted
+throughout the whole system. It was quite recognized that this method
+still left much to be desired, and the economy resulting from the use
+of an improved form was very marked.
+
+From a large number of trials very carefully carried out by Professor
+Gutermuth, it was found that more than 70 per cent. of the total
+number of calories in the fuel employed was absorbed by the air and
+transformed into useful work. Whether gas or coal be employed as the
+fuel, the amount required is so small as to be scarcely worth
+consideration; according to the experiments carried out, it does not
+exceed 0.09 kilo. per horse power and per hour, but it is scarcely to
+be expected that in regular practice this quantity is not largely
+exceeded. Professor Weyrauch has also carefully investigated this part
+of the subject and fully confirms, if he, indeed, does not go beyond
+Professor Gutermuth. He claims that the efficiency of fuel consumed in
+this way is six times greater than when burnt under a boiler to
+generate steam. He goes so far as to assert that with a good method of
+heating the air, not only can all the losses due to the production and
+the transmission of the compressed air be made good, but also that it
+will actually contain more useful energy at the motor than was
+expended at the central station in compressing it.
+
+According to Professor Riedler, from 15 to 20 per cent. above the
+power at the central station can be obtained by means at the disposal
+of the power users, and it has been shown by experiment that by
+heating the air to 250 deg. Cent. an increased efficiency of 30 per
+cent. can be obtained. Better results than those heretofore obtained
+may, therefore, be confidently expected with a more perfect and
+economical application of the fuel in heating the air, and a better
+means of regulation in admitting it to the motors. In his report
+Professor Riedler indicates a method by the use of which he considers
+considerable advantages may be secured. This is the heating the air in
+two stages instead of at one operation, and passing it through two
+motors, to the first of which the air is admitted heated only to a
+moderate extent; the exhaust from this motor then passes into a second
+heater and thence into the second motor. A series of experiments with
+this arrangement were recently carried out.
+
+The consumption of air per brake horse power was reduced from 812
+cubic feet per hour, a favorable duty in the single motor, to 720, and
+in the best result to 646 cubic feet with the two motors and double
+heaters. It should be added that these trials were carried out with
+steam engines but ill adapted for the purpose. It is to be regretted
+that the experiments of Professor Riedler could not have been
+conducted with more perfect appliances, but it must be borne in mind
+that the utilization of compressed air, especially as regards the
+motors, is still in a very imperfect stage, and that a great deal
+remains to be done before the maximum power available at the motor can
+be obtained. Investigations in this direction for a considerable time
+to come must be directed, therefore, toward improving the design and
+construction of the motors and the treatment of the air at the point
+of delivery into the engine.
+
+A large number of motors in use among the subscribers to the
+Compressed Air Company, of Paris, are rotary engines developing one
+horse power and less, and these in the early times of the industry
+were extravagant in their consumption, to a very high degree. To some
+extent this condition of things has been improved, chiefly by the
+addition of better regulating valves to control the air admission.
+
+As altered, the two horse power rotary motors, when employed as cold
+air engines, a method often desired in special industries, consume
+1,059 cubic feet per hour and per indicated horse power; with a
+moderate degree of heating, say to 50 deg. Cent., this consumption
+falls to 847 cubic feet. The efficiency of this type of rotary motors
+with air heated to 50 deg. may now be assumed at 43 per cent., not a
+very economical result, it is true, and one that may be largely
+improved, yet it is evident that with such an efficiency the use of
+small motors in many industries becomes possible, while in cases where
+it is necessary to have a constant supply of cold air, economy ceases
+to be a matter of the first importance.
+
+Some useful results were obtained with compressed air used in crank
+engines; it is to be regretted that with this, also, apologies have to
+be made for the imperfect design and construction; they were old steam
+engines, some of those of two horse power losing from 25 to 30 per
+cent. by their own friction; some of the others tried, however, were
+far better, a newer type losing only from 8 to 10 per cent., while the
+80 horse power referred to below showed an efficiency of 91 per cent.
+From these trials Prof. Riedler deduces--assuming 85 per cent.
+efficiency--a consumption of 611, 752, and 720 cubic feet per brake
+horse power. It is very evident from the foregoing that the Compressed
+Air Company, of Paris, will never do itself justice until as much
+thought and care has been devoted to the economical use of the motive
+power as has been expended in the means of producing it, and Professor
+Riedler's recent investigations should be especially useful in this
+respect. The question has indeed attracted the attention of more than
+one manufacturer, and reference is made to a particular type of small
+rotary motors which are being constructed by MM. Riedinger & Co., and
+which is stated have given very excellent results. These engines were
+specially used for working sewing machines and developed on the brake
+an efficiency of 34.07 and 51.63 foot pounds per second. Trials were
+made with a half horse power variable expansion Riedinger engine.
+
+
+  TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
+ ______________________________________________________________
+                                               |       |
+  Number of trials.                            |   I.  |   II.
+ ______________________________________________|_______|_______
+                                               |       |
+ Initial air pressure.     lb. per square inch |    86 | 71.8
+      "      temperature.           deg. Cent. |   +12 |  +170
+ Ft. pounds per second  measured on the brake. | 51.63 | 34.07
+ Revolutions per minute.                       |   384 |  300
+ Consumption of air for one horse power per    |       |
+    hour.                                      | 1,377 |  988
+ ______________________________________________|_______|_______
+
+
+  TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
+ _____________________________________________________________________
+                                           |      |      |      |
+  Number of trials.                        |  I.  |  II. | III. |  IV.
+ __________________________________________|______|______|______|_____
+                                           |      |      |      |
+ Initial pressure of air.  lb. per sq. in. |   54 | 69.7 |   85 | 71.8
+      "  temperature of air.    deg. Cent. |  170 |  180 |  198 |    8
+ Final        "        "            "      |   25 |   20 |  ... |   25
+ Revolutions per minute.                   |  335 |  350 |  310 |  243
+ Foot pounds per second measured on        |      |      |      |
+    brake.                                 |  271 |  477 |  376 |  316
+ Consumption of air per horse power        |      |      |      |
+    and per hour.                          |  883 |  791 |  900 |1,148
+ __________________________________________|______|______|______|______
+
+  TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
+ ___________________________________________________________________
+                  | R p  |      |                  |
+                  | e e  | I    |                  | Consumption of
+                  | v r  | n    |   Temperature    |  air per horse
+                  | o    | d h p|      of air.     |  power and per
+                  | l m  | i o o|                  |      hour.
+                  | u i  | c r w|__________________|________________
+                  | t n  | a s e|         |        |       |
+    Motor.        | i u  | t e r|Admission|Exhaust.|Nominal| Brake
+                  | o t  | e   .|         |        | horse | horse
+                  | n e  | d    |         |        | power.| power.
+ _________________|_s_.__|______|_________|________|_______|________
+                  |      |      |  deg. C | deg. C |       |
+ Nominal 80 horse | 54.3 | 72.3 |    129  |   21   |  469  |  517
+ power single     | 54.3 | 72.3 |    152  |   29   |  437  |  475
+ cylinder Farcot  | 54.0 | 72.3 |    160  |   35   |  424  |  465
+ engine.          | 40   | 65.0 |    170  |   49   |  438  |  477
+ _________________|______|______|_________|________|_______|________
+
+
+These motors, it may be assumed, represent the best practice that has
+been obtained up to the present time in the construction of compressed
+air motors; with the smallest of them, indicating about one-tenth of a
+horse power, the consumption of air, when admitted cold, was 1377
+cubic feet and 988 cubic feet when the air was heated before
+admission. The half horse power engine consumed 1148 cubic feet of
+cold air, and of heated air 791 cubic feet per horse power and per
+hour. It should be mentioned that these, the most valuable and
+suggestive of all the trials carried out by Professor Riedler, were
+conducted with the greatest care, two distinct modes of measuring the
+air supplied being followed on two occasions for each test; it may
+therefore be considered that the results given are absolutely correct.
+The trials were made with an old single cylinder Farcot engine,
+nominally of 80 horse power, but indicating over 72.3. With this
+engine the consumption of air varied from 465 to 517 cubic feet, the
+larger consumption being due to the lower temperature (129 deg. Cent.)
+to which the air was raised before admission; in the most economical
+result the temperature was 160 deg. Cent. The volumes of air referred
+to are, of course, in all cases taken at atmospheric pressure.
+
+Among the important losses that have to be reckoned with in every
+system of distributing motive power from a central station--whether by
+steam or by electricity, water, or compressed air--losses must occur
+in the mains by which the power generated is transferred from the
+point of production to that of consumption. In the case we are now
+considering very careful tests were conducted in 1889 by Professor
+Kennedy, to whose report we have already referred. Since that time
+important changes have been made by the Compressed Air Company, at
+Paris, in the details of distribution, and on this account the later
+investigations of Professor Riedler on the losses due to this cause
+are of special interest.
+
+Before its admission into the mains a certain loss occurs at the St.
+Fargeau station, in the large reservoirs to which the air is delivered
+from the compressors. This question of preliminary storage was one
+that received considerable attention when the designs of the new
+station on the Quai de la Gare were being considered. It was intended
+to construct very large receivers in the basement of the station, and
+the foundations for these were even commenced. It was decided,
+however, that for the 10,000 horse power which is to form the first
+section of the new station, and for which the complete system of mains
+has already been laid down, storage reservoirs would be unnecessary,
+and a saving both in first cost and subsequent loss of air would be
+effected. The length of mains of 19.69 in. diameter is so considerable
+that they will contain at all times a sufficient reserve of air to
+prevent any irregularities in pressure at the motors.
+
+With reference to these mains it may be mentioned that, unlike the
+11.81 in. conductors of the St. Fargeau system, of which 17 kilometers
+are laid in the Paris subways, the new mains are entirely laid in the
+streets, it having been found impossible to make room for these large
+pipes in the subways already crowded with telegraph and telephone
+wires, water mains, etc.
+
+Professor Riedler investigated the two causes of loss in the
+mains--leakage and resistance. It was superficially evident that the
+mains of the old system were so well laid, and the joints so well
+designed, that the loss from leakage was never a serious one. In
+order, however, to ascertain the amount accurately, a series of
+careful experiments were carried out by Professor Gutermuth with the
+11.81 in. mains of the St. Fargeau system.
+
+
+  EXPERIMENTS ON LEAKAGE IN MAINS.
+
+---------------------------------------------------------------------
+| |                 |         |               |             | L P A |
+| |                 |         | Air Pressure  |   Loss of   | o e i |
+| |                 |         |  in Mains.    |  Pressure.  | s r r |
+| |                 |         |---------------|-------------| s     |
+| |                 |         |  B    |       |      |      |   C D |
+| |System of Mains  | Length. |  e   T|       |      |      | o e e |
+|N|    Tried.       |         |  g   r|  At   |      |      | f n l |
+|u|                 |         |A i o i| End   |During| Per  |   t i |
+|m|                 |         |t n f a|  of   |Trials|Hour. | A . v |
+|b|                 |         |  n   l|Trials.|      |      | i   e |
+|e|                 |         |  i   s|       |      |      | r o r |
+|r|                 |         |  n   .|       |      |      |   f e |
+| |                 |         |  g    |       |      |      |     d |
+--+-----------------+---------+-------+-------+------+------+-------|
+| |                 | yards.  | atm.  |  atm. |      |      |       |
+|1|Southern reseau  |         |       |       |      |      |       |
+| | to Place de la  |         |       |       |      |      |       |
+| | Concorde.       |  9,980  | 6.5   |  6.0  | 0.5  | 1.5  |  3    |
+|2| Total reseau    | 18,500  | 6.9   |  5.9  | 1.0  | 1.5  |  6.3  |
+|3|To Place de      |         |       |       |      |      |       |
+| | la Concorde     |  9,980  | 7.0   |  6.43 | 0.57 | 0.75 |  2.16 |
+|4|Total reseau     | 18,500  | 6.7   |  5.28 | 0.88 | 1.32 |  5.5  |
+|5|Northern reseau  |         |       |       |      |      |       |
+| | to Rue de Belle-|         |       |       |      |      |       |
+| | ville.          |  1,530  | 6.0   |  5.0  | 1.0  | 0.6  |  2.3  |
+|6|To the Rue des   |         |       |       |      |      |       |
+| | Pyrenees.       |    600  | 6.1   |  3.7  | 2.4  | 0.56 |  2.2  |
+---------------------------------------------------------------------
+
+
+These trials refer to the mains running from the St. Fargeau station
+to the Place de la Concorde, a length of 9.142 kilometers; to the
+whole system of mains, 16.5 kilometers; to the northern mains running
+from St. Fargeau to the Rue de Belleville, 1.4 kilometers; and from
+St. Fargeau to the Rue des Pyrenees, 6.5 kilometers. It will be seen
+from the figures given in the table that the actual loss is small, and
+it is stated that this is due chiefly to the elastic joint employed
+throughout the system, excepting in the Rue de Belleville, where rigid
+couplings are used, and continual trouble is experienced from loss by
+leakage. In all cases the losses given are the maximum, which only
+occur under the most unfavorable conditions.
+
+It was found, during the first, second, and fourth tests, that
+considerable leakage occurred between the St. Fargeau central station
+and the Rue de Belleville. During the trials two and four, an
+uncertain amount of loss occurred from the consumption of air required
+to work the pneumatic clocks, and also motors in the circuit, that
+could not be stopped. The tests two and four include all losses in the
+service pipes, as well as the mains.
+
+The production of compressed air at the central station is assumed at
+30,000 cubic feet per hour (atmospheric pressure), and in all cases
+the loss in the mains is taken as a percentage of the total
+production.
+
+The losses due to resistance in the mains were also examined with
+great care, over independent sections, as well as through the complete
+_réseau_. During the early part of these trials, an unusual and
+excessive loss was recorded, the cause of which could not be at first
+ascertained. At intervals along these mains are placed a number of
+water reservoirs which receive the water injected into the mains; in
+addition to these the direct flow of the air is interrupted by
+numerous siphons, the stop valves to branches, etc. Investigation
+showed that the presence of these reservoirs created considerable
+resistance on account of an increased and subsequently reduced
+section. The exact loss from this cause was, therefore, carefully
+measured, as well as the losses existing in the mains not so
+interrupted. The results show that the loss by expansion at one
+reservoir, when the speed of the air flow was 23 ft. per second, was
+equal to 0.15 atmosphere; with a speed of 29 ft. 6 in. per second, it
+amounted to 0.2 atmosphere.
+
+Therefore, the presence of five such reservoirs would cause a loss in
+pressure equal to one atmosphere. This very undesirable arrangement is
+not repeated in the new system, the sumphs being connected in such a
+way as not to modify the section of the tube, nor consequently the
+pressure of the air. The presence of the siphons and stop valves did
+not seem to affect the pressure to any measurable extent. The
+following table contains a list of the more important mains tested,
+and it may be mentioned that the resistance, due to the reservoirs,
+was at first partially included. The trials were carried out while the
+mains were not being drawn upon by subscribers.
+
+
+-----------------------------------------------------------------------
+                                                   |            |
+Section of Mains Tested.                           |  Length.   |No. of
+                                                   |            |Tests.
+                                                   |            |
+---------------------------------------------------+------------+------
+                                                   |  yards.    |
+From the central station to the end of reseau and  |            |
+  back to central station by return circuit        |  18,100    |   7
+From the central station to the Rue Fontaine au    |\ 14,600    |/  3
+  Roi                                              |/  9,900    |\  4
+From the central station to the Rue de la          |            |
+  Charonne                                         |   9,490    |   5
+From the Rue de la Charonne to Fontaine au         |            |
+  Roi                                              |   4,770    |   3
+From the central station to the Avenue de la       |            |
+  Republique                                       |   1,860    |   8
+Various trials on different lengths of mains       |770 to 8,000|  11
+-----------------------------------------------------------------------
+
+
+Over the whole system of 16.5 kilometers, which was also tested when
+no air was being taken off, there were four reservoirs of considerable
+size, and which offered a large resistance with a corresponding loss
+of pressure; on the line there were also 23 siphons and 42 stop
+valves.
+
+These trials were repeated several times to secure accuracy, and the
+speed of the air was brought to 49 ft. a second. The results obtained
+in one of these trials may be taken as an example. The main between
+the Rue St. Fargeau and the Fontaine au Roi, on which there are no
+collecting reservoirs, but three siphons and eight stop valves, gave,
+with an average speed of 21 ft. 3 in., a loss in pressure of 0.05
+atmosphere for each kilometer of main.
+
+From these experiments it would appear that, assuming a speed of 21
+ft. per second, a loss in pressure of one atmosphere would correspond
+to a distance of 20 kilometers; that is to say, a central station
+could extend its mains on all sides with a radius of 20 kilometers,
+and the motors at the ends of the lines would receive the air at a
+pressure 15 lb. less than at the central station. Professor Riedler
+states that as an actually measured result, the velocity of the air
+through the mains of the St. Fargeau system is 19 ft. 8 in. per
+second, and that the loss in pressure per kilometer is 0.07
+atmosphere. From this it follows that including the resistances due to
+the four reservoirs, and other obstructions actually existing, an
+allowance of one atmosphere loss on a 14 kilometer radius is ample. By
+increasing the initial pressure of the air, much better results can be
+obtained, and future attention in practice should be devoted to this
+point. The amount of work required to compress air does not increase
+in the same ratio as the pressure, and for this reason considerable
+economy can be effected at the first stage, and the loss in the mains
+will be reduced.
+
+Passing to another point of the same subject, Professor Riedler
+considers the best dimensions that should be given to the mains.
+Resistance decreases with an increase in the diameter of these and in
+direct ratio to their diameter; for this reason--still assuming a
+pressure corresponding to a velocity of 20 ft. per second--with a fall
+of one atmosphere, a length of 40 kilometers could be succesfully
+worked.
+
+The mains of the new _réseau_ for the Quai de la Gare station are
+19.69 in. in diameter; they are built up of steel plates riveted, and
+this Professor Riedler considers to have been a serious error on
+account of the extra resistance offered by the large number of rivet
+heads.
+
+The following may be taken as a brief summary of Professor Riedler's
+conclusions: Recent improvements in central station practice have
+resulted in an increased efficiency of about 30 per cent. in the
+compressors, but this benefit can only be realized when the new
+station is in operation. That the small and very imperfect air engines
+in use on the system give an efficiency of 50 per cent., while with
+ordinary steam engines driven by air an efficiency of 80 per cent. can
+be reached with a very small expenditure of fuel for heating the air
+before admitting it into the motor. That special attention should be
+given to the improvement of air engines, and that with increased
+initial pressures at the central station the distance of the
+transmission can be very considerably augmented. Finally, Professor
+Riedler claims that power can be transmitted by compressed air more
+conveniently and more economically than by any other means.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12810.]
+
+
+
+
+THE BUILDERS OF THE STEAM ENGINE--THE FOUNDERS OF MODERN INDUSTRIES
+AND NATIONS.[1]
+
+[Footnote 1: An address delivered at the Centennial Celebration of the
+American Patent System, Washington, April, 1891.]
+
+By Dr. R.H. THURSTON, Director of Sibley College, Cornell University.
+
+
+Papin, Worcester, Savery, were the authors of the period of
+application of the power of steam to useful work in our later days.
+The world was, in their time, just waking into a new life under the
+stimulus of a new freedom that, from the time of Shakespeare, of
+Newton, and of Gilbert, the physicist, has steadily become wider,
+higher, and more fruitful year by year. All the modern sciences and
+all the modern arts had their reawakening with the seventeenth
+century. Every aspect of freedom for humanity came into view in those
+days of a new birth. Both the possibility of the introduction of new
+sciences and of new arts and the power of utilizing all new
+intellectual and physical forces came together. The steam engine could
+not earlier have taken form, and, taking form, it could not have
+promoted the advance of civilization in the earlier centuries. The
+invention becoming possible of development and application, the
+promotion of the arts and of all forms of human activity became a
+possible consequence of its final successful introduction into the
+rude arts that it was to so effectively promote and improve.
+
+But the work of these inventors was in itself but little more
+important than that of the Greek inventor of the steam ælopile, for
+each brought forward a machine which was, from a business point of
+view, utterly impracticable, and which, in each case, only served to
+show that a better device might prove useful and lead the way to its
+introduction. The merit of the inventors of the eighteenth century was
+that they were _able_ to lead the way, to point out the path to
+success, to furnish evidence of the value of the coming, crowning
+invention. The "fire engines," as they were then called, of these now
+famous men were merely contrivances by the use of which the pressure
+of confined steam of high tension could be brought to act on the
+surface of a mass of confined water, forcing it downward into pipes
+through which it was led off and upward to a higher level; and thus a
+mine could be drained, ineffectively and expensively to be sure, but
+vastly more satisfactorily than by the animal power of the time. The
+machine of Savery was the best of all; but that was only a somewhat
+improved and manageable rearrangement of the engines of Papin and
+Worcester. And, after all, Papin, the greatest man of science perhaps
+of his time, died in poverty; Worcester languished in prison his whole
+life, and the later efforts of his widow brought nothing by way of a
+return for his invention; nor did either they or their successor,
+Morland, make the introduction of the engine either general or
+remunerative.
+
+Savery, coming on the stage at more nearly the right time to seize
+upon an opportunity, gained more than either of his predecessors; but
+we have no evidence that he ever acquired any large compensation or
+met with any remarkable business success in the introduction of the
+rude engine which bore his name; nor did Desaguliers, the great
+philosopher, or even Smeaton, the great engineer, of the later years
+of that century, make any great success of it. It was reserved for
+Watt to reap the harvest. But, though he so effectively reaped where
+his predecessors had sown, Watt is not the greatest of the inventors
+of the steam engine, if we rate his standing by the magnitude of the
+improvement which marked his reconstruction of the engine.
+
+It was NEWCOMEN who made the modern steam engine.
+
+When Newcomen came forward the labors of Worcester in Great Britain
+had sufficed to attract the attention of all intelligent men to the
+character of the problem to be solved, and to convince them of its
+importance and promise. The work of Savery had shown the
+practicability of the solution of the problem, both in mechanics and
+finance. He succeeded, though under great disadvantages and
+comparatively inefficiently. Once the task had been performed, though
+ever so rudely, the rest came easily and promptly. The defects of the
+Savery system were at once recognized; its great wastes of heat and of
+steam were noted, and the fact that they were inherent in the system
+itself was perceived. A complete change of type of machine was
+obviously requisite; it was this which constituted the greatest
+invention in the whole history of the steam engine, from Hero's time
+to our own; and to Newcomen we owe more than to any other man who ever
+lived, the value of the invention itself being considered, and the
+importance of the services of its introducer being left out of
+consideration. No such complete and vital improvement and modification
+of the machine has ever been effected by any other man, Watt and
+Corliss not excepted. Newcomen and his comrade Calley--we do not know
+how the honors should be divided--produced the modern steam engine.
+Its predecessor, the Savery engine, had been a mere steam "squirt."
+Newcomen constructed an engine. Savery built a simple combination of
+cylindrical or ellipsoidal vessels which wastefully and at once
+performed all the several offices of engine, pump, condenser, and
+boiler; Newcomen divided the several elements among as many parts,
+each especially adapted to the performance of its task in the most
+effective manner--the condenser excepted; for that was Watt's
+principal invention--and thus produced the first steam engine in the
+modern sense of that term.
+
+It was Newcomen, not Watt, who gave us the train of mechanism that we
+now call the steam engine. It is to Newcomen, rather than Watt, that
+we owe the highest honors as an inventor in this series of the most
+important of all the products of the inventive genius of mankind.
+Newcomen brought into existence a new, the modern, type of engine, and
+effected the greatest revolution that has been recorded in the history
+of the arts. Without Newcomen, there might have been no Watt; without
+Watt, there very possibly may not even yet have been brought into
+existence that giant of our time, whose mighty powers are employed
+more effectively than ever those of Aladdin's genii, in building
+palaces, in transporting men and material, in doing the work of the
+whole world; promoting the welfare of the race, in a single century,
+more than had all the forces of matter and mind together in the whole
+previous history of the world. Newcomen laid down a foundation beneath
+our whole economic system, out of sight, almost, but the essential
+base, nevertheless, on which Watt and his successors have carried up
+the great superstructure which seems to us to-day so imposing; which
+is so tremendous in magnitude, importance, and result. If to any one
+man could be assigned the credit, it is Newcomen who is to be
+considered the inventor of the steam engine.
+
+James Watt, indisputably the great inventor that he was, found the
+steam engine ready to his hand, applied himself to its improvement,
+and made it substantially what it is to-day. His most important work,
+the most unique service performed by him, was, however, that of its
+adaptation and introduction to do the work of the world. James Watt
+was the inaugurator of the era of refinement of the machine already
+invented, and the greatest of its builders and distributors. His
+inventions were all directed to the improvement of its details, and
+his labors to its introduction and its application to the myriad tasks
+awaiting it. By the hands of Watt it was made to pump water, to spin,
+to weave, to drive every mill; and he it was who gave it the form
+demanded by Stephenson, by Fulton, by the whole industrial world, for
+use on railway and steamboat, and in mill and factory, throughout the
+civilized countries of the globe. It was this great mechanic who
+showed how it might be made to do its work with least expense, with
+highest efficiency, with greatest regularity, with utmost
+concentration of power.
+
+The grand secret of his success was historical and economic, as much
+as scientific and mechanical. He brought out his inventions just when
+the world was economically and historically ready for them. The age of
+authority was past, that of freedom was come; the period of political
+and ecclesiastical tyranny was gone by, and that of the spontaneous
+development of man was arrived. The great invention was offered to a
+world ready and needing it, and, more than all, competent, for the
+first time in history, to make and use it.
+
+James Watt was himself a product of the modern scientific spirit. He
+was a man so constituted mentally that he could apply scientific
+methods to problems which his logical and clairvoyant mind could
+readily and exactly formulate the instant he was led to their
+consideration in the natural course of his progress. He was the ideal
+great inventor and mechanic. With inventive genius he combined strong
+common sense--not always a quality distinguishing the inventor--clear
+perception, breadth of view, and scientific method and spirit in the
+treatment of every question. His natural talent was re-enforced by an
+experience and an environment which led him to develop these ways and
+this mental habit. His trade was that of an instrument maker, his
+position was that of custodian and repairer of the apparatus of
+Glasgow University. He had for his daily companions and stimulus the
+great men and ozonized atmosphere of that famous institution. He kept
+pace with advancing science, and was imbued, both naturally and
+through contact with its promoters, with that ambition and those
+aspirations which are the life element of all progress, whether
+scientific or other. He was aware of the nature of the problems
+seeking solution at the time, and familiar with the state of his own
+art and that of the great mechanicians about him. Everything was
+favorable to his progress, so soon as he should be given an
+opportunity to take a step in advance and to come into sight at the
+front. The man and the time were both ready, and all conditions,
+internal and external, social and personal, were favorable to his
+development.
+
+The invention upon which Watt was to improve was at his hand. A word
+in regard to its status at the moment will throw some light upon that
+of Watt and his creation. Newcomen had, as we have seen, produced the
+modern type of steam engine as an original and wholly novel invention.
+But this machine, marvelous as an advance upon pre-existing forms of
+the steam engine, was still, as seen in the light of recent knowledge
+and experience, exceedingly defective. The purpose of a steam engine
+is to convert into usefully applicable power the hidden energy of
+fuel, stored ages ago in the earth, by transformation, through the
+action of vegetation, from the original form, the heat of the sun,
+into an available form for reconversion, through thermodynamic
+operations. In this process of reconversion, whatever the nature of
+the machine used in the operation, there are invariably wastes, both
+of heat required for conversion into power and of the power thus
+produced. That machine which effects the most complete transmutation
+of the heat supplied it into mechanical power, which wastes the least
+amount of heat supplied and of power produced, is the best engine, and
+constitutes an advance over every other.
+
+It was this reduction of wastes that made the Newcomen engine so much
+superior to that of Savery. The latter was by far the simpler and less
+costly construction; but its enormous losses, both of heat and of
+power, mainly the former, however, made it an extravagant expenditure
+of money to buy and use it. The Newcomen engine, costly and cumbrous,
+comparatively, nevertheless wasted so much less heat and steam and
+fuel that no one could afford to buy the cheaper machine. Before
+considering what Watt accomplished, we may find it profitable to
+examine into the nature of the wastes which characterized this later
+and better machine on which he effected his improvements.
+
+The Newcomen engine consisted of a steam boiler, a steam cylinder, a
+beam and a set of pumps. By making the boiler do its work separately,
+the engine acting independently, and the pumps as a detached portion
+of the mechanism, this inventor had reduced to an enormous extent
+those wastes of heat and of steam and of fuel which were unavoidable
+in the older machines in which all these parts were represented by a
+single vessel, or by two at most, in each element. In the Savery
+engine, the steam entering first heated up the interior of the working
+vessel to its own temperature, and held it at that temperature in
+spite of the cooling influence of the water present. This consumed
+large quantities of heat. It then was compelled to surrender probably
+much greater quantities still to the water itself, coming in direct
+contact as it did with its surface. If the water was agitated, either
+by the currents produced during its ingress or by the impact of the
+steam entering the vessel, this heating action penetrated to
+considerable depths and perhaps even warmed the whole mass very far
+above its initial temperature. This constituted another and a very
+serious loss. Then, again, as the water was gradually driven out of
+the containing vessel by the steam pressing on its surface, new
+portions of the vessel and new masses of water were continually
+brought in contact with the hot steam, taking its full temperature,
+and thus, often, probably, finally heating the whole mass of the
+forcing vessel, and a large proportion of the water as well, up to the
+temperature, approximately at least, of the steam itself. Thus in many
+instances, if not always, vastly more heat and steam were wasted, in
+this undesirable heating of water and forcing vessel, than were
+usefully employed in the legitimate work of raising the water to a
+higher level. In fact, in some cases in which these quantities were
+measured, the wastes were one hundred times as much as the work done.
+One per cent. of the heat supplied did the work; while ninety-nine per
+cent. was thrown away. One dollar or one shilling expended for fuel to
+do the work was accompanied by an expenditure of ninety-nine dollars
+or shillings thrown away, because of the imperfections of the system
+and machine. The whole history of the development of the steam engine
+has been one of gradual reduction of these wastes; until to-day, our
+best engines only compel us to spend five dollars for wastes to each
+dollar paid out for useful work. A business man would think that amply
+extravagant, however, and the man of science is continually seeking
+methods of evading these losses, a large proportion of which are now
+apparently unavoidable in heat engines, by finding some new system of
+heat and energy transformation.
+
+Watt was the instrument maker and repairer at Glasgow University in
+the year 1763. His companions were, among others, the professors of
+natural philosophy and of mathematics in the university. Their
+conversation and their frequent presentation of practical and
+scientific questions and problems stimulated his naturally inquiring
+and inventive mind to the pursuit of a thousand interesting and
+promising schemes for the improvement of existing methods and
+machinery. Dr. Robison, then a student, suggested the invention of a
+steam carriage for use on common roads, and the young mechanician at
+once began experiments that, resulting in nothing at the time, were
+nevertheless continued, in one or another form, until all modern
+applications of steam came into view. Dr. Black taught Watt chemistry,
+then a newly constructed science, and led him on to the discovery,
+finally made by them independently, of the fact and the magnitude of
+the latent heat of steam; the discovery coming of a series of
+scientifically planned and accurately conducted investigations, such
+as the man of science of to-day would deem creditable. The treatises
+of Desaguliers and others on physics gave Watt a knowledge of that
+domain of natural phenomena which stood him in good stead later, when
+he attempted to apply its principles to the reduction of the wastes of
+the steam engine.
+
+It was while at Glasgow University, working under such influences and
+in such an atmosphere of intellectual activity, that the accident of
+the Newcomen model engine needing repair brought to the mind of Watt
+the opportunity which, availed of at once, made him famous and gave
+the world its greatest aid, its most powerful servant. The observing
+mind of the great mechanic immediately noted its defects, sought their
+causes, found their remedy. He discovered, at once, that the quantity
+of steam entering the cylinder of the little engine has four times the
+volume of the cylinder receiving it: in other words, three-fourths of
+that steam must be condensed immediately on entrance. This meant,
+evidently, that only one-fourth of the steam supplied was utilized,
+and even then inefficiently, in doing its work. The reason of this was
+as easily seen, immediately the fact was revealed. As Watt himself
+expressed it, the causes of this loss, causes which would obviously be
+exaggerated in a small engine, were: "First, the dissipation of heat
+by the cylinder itself, which was of brass and both a good conductor
+and a good radiator. Secondly, the loss of heat consequent upon the
+necessity of cooling down the cylinder at every stroke in producing
+the vacuum. Thirdly, the loss of power due to the pressure of vapor
+beneath the piston, which was a consequence of the imperfect method of
+condensation." This much determined, the next step looked toward the
+confirmation of his conclusions and the remedy of the defects.
+
+To meet the first difficulty he made a cylinder of wood, soaked in oil
+and baked, a non-conducting and non-radiating material. Then he was
+able to determine with some accuracy the quantities of steam and
+injection water used in the engine; and a comparison with the original
+cylinder and its operation showed that not only four times the
+quantity of steam, but also four times the amount of injection water
+was used as was necessary, assuming wastes checked. Further scientific
+research on the part of Watt gave him measures of specific heats of
+the metals and of wood, the specific volumes of steam at various
+working pressures, the evaporative efficiency of boilers, the
+pressures and temperatures of steam in the boiler under specified
+conditions, the quantities of steam and of water required for the
+operation of his little condensing engine.
+
+Then came his enunciation of the grand principle of economy in the
+construction and operation of the steam engine: "Keep the cylinder as
+hot as the steam which enters it," as he expressed it. This was Watt's
+guiding principle, as it has been that of all his successors in the
+improvement of the economic performance of the steam engine and of all
+other heat engines. The great source of waste is the dispersion of
+heat, uselessly, which should be applied to the production of work by
+its transformation, thermodynamically, into the latter form of energy.
+The second form of waste is that of power thus produced in the
+unprofitable work of moving the parts of the engine itself; and the
+third is that of heat by transfer, without transformation, by
+conduction and radiation to surrounding bodies. In modern engines, the
+latter is but three or five per cent., in the best cases; the second
+waste constitutes perhaps ten per cent.; while the first of these
+losses amounts very usually to seventy per cent., of which last
+one-third or one-fourth is of the kind discovered by Watt, the rest
+being the thermodynamic waste incident to all known methods of
+operation of heat engines, and apparently unavoidable. In our very
+best and largest engines, the waste found by Watt to constitute three
+fourths of all heat supplied has been brought down to ten per cent., a
+fact which well exemplifies the advances made since his time of
+apprenticeship by himself and his successors of this nineteenth
+century. The steam engine of to-day, in its most successful operation,
+gives us twenty-five times as much power from a pound of coal as did
+the engine that the great inventor sought to improve: this is the
+magnificent fruit of that one discovery of James Watt, and of
+application of the simple principle which he so concisely and clearly
+stated.
+
+The method adopted by Watt to secure a remedy, so far as practicable,
+of this defect of the older machine was as simple and as perfect as
+was the principle which it embodied. He first removed from the
+cylinder the prime source of its wastes; providing a separate
+condenser, and thus avoiding the repeated chilling of its surfaces by
+the cold water used in condensing the steam at exhaust, and also
+permitting its strokes to be made with far greater frequency, thus
+giving less time for cooling by the influence of the remaining vapors
+after condensation. He next went still further, and provided the
+cylinder with a closed top, keeping out the air, and a "jacket" of hot
+boiler steam to _keep_ it as hot as the steam which entered it. These
+were the two great improvements which converted the first real steam
+engine into an economical form of heat engine and essentially finished
+the work so grandly begun by Newcomen and Calley. These changes gave
+us the modern steam engine; and these are Watt's first and greatest,
+but by no means only, contributions to the production of the modern
+world with all its comforts, its luxuries and its opportunities for
+material, intellectual and moral advancement of individual and of
+race. His work was to this extent complete in 1765.
+
+But Watt did not stop here. There still remained for him the no less
+important and the, in some senses, still more imposing, work of
+finding employment for the new servant of mankind and of setting it at
+its work of giving the human arm a thousand times greater strength, to
+the mind of man uncounted opportunities to promote the advancement of
+knowledge, of civilization, of every good of the race. His was still
+the task of adapting the new machine to all the purposes of modern
+industry. It had been hitherto confined to the task of raising water
+from the depths of the mine; it was now to be harnessed to the railway
+train; to be made to drive the machinery of the mill, to apply its
+marvelous power to the impulsion of the river boat and ocean steamer;
+to furnish energy, through endless systems of transfer and use, to
+every kind of work that man could devise and should invent. All this
+meant the giving of the machine forms as various as the purposes to
+which it was to be devoted. It had previously only raised and
+depressed a rod; it must now turn a shaft. It had then only operated a
+pump; it must now turn a mill, grind our grain, spin our threads,
+weave our cloths, drive our shops and factories, supply the powerful
+blast of the iron furnace. It must be made to move with the utmost
+conceivable regularity, and must, with all this, do its work in the
+development of the hidden energy of the fuel, with the greatest
+possible economy, through the expansion of its steam. All this was
+achieved by James Watt.
+
+The invention of the double-acting engine, in which the impulsion of
+the steam is felt both in driving the piston forward and in forcing it
+backward, both upward and downward, the application of its force
+through crank and fly wheel, the creation of an automatic system of
+governing its speed, and the discovery of the economy due to its
+complete expansion, were all improvements of the first magnitude, and
+of the greatest practical importance; and all these were in rapid
+succession brought into existence by the creative mind that had
+apparently been brought into the world for the express purpose of
+giving to the hand of man this mighty agent, to perfect the mightiest
+power that mind of man has yet conceived.
+
+But to do the rest required more than inventive genius and mechanical
+skill. It demanded capital and the stored energy of labor and genius
+in other fields, directed by the mind of a great "captain of
+industry." This came to Watt through Matthew Boulton, a manufacturer
+of Birmingham, whose father and ancestors had gradually and
+toilsomely, as always, accumulated the property needed for the
+prosecution of a great business. The combination of genius and capital
+is always an essential to success in such cases; and good fortune, a
+Providence, we may well say, brought together the genius and the
+capitalist to do their work, hand in hand, of providing the world with
+the steam engine. Hand in hand they worked, and all the world to-day,
+and the race throughout its future life, must testify gratitude for
+the inexpressible obligations under which these two men have placed
+them, doing the work of the world.
+
+Boulton & Watt, the capitalist with the inventor, gave the world the
+steam engine, finally, in such form and in such numbers that its
+permanent establishment as the servant of man was insured. The
+capitalist was as essential an element of success as was the inventor,
+and, in this instance, as in a thousand others, the race is indebted
+to that much-abused friend of the race, the capitalist, for much that
+it enjoys of all that it desires. The industry and patience, the skill
+and the wisdom required for the accumulation of this energy stored for
+future use in great enterprises is as important, as essential, as
+inventive power or any other form of genius. Talent and genius must
+always aid each other. This firm was established in 1764 and its main
+resources, aside from the bank account, were Watt's patent, about
+expiring, and Watt's genius, and Boulton's talent as a man of
+business. The patent was extended for twenty-four years, the new
+inventions of Watt, now beginning to pour from his prolific brain in a
+wonderful stream, were also patented, and the whole works were soon
+employed upon the construction of engines for which numerous orders
+soon began to pour in upon the now prosperous builders. The patent law
+established Boulton and Watt and the firm paid back the nation with
+handsome usury, giving it unimaginable profits indirectly through its
+control of the work of the world and large profits directly through
+the business brought them from all parts of the then civilized globe.
+There has never, in the history of the world, been a more impressive
+illustration of the value to a nation of that generous public policy,
+that simply just legislation, which gives to the man of brain control
+of the products of his mind. For a hundred years, Great Britain has,
+largely through her encouragement of the inventor and her protection
+of his mental property by securing the fruits of his labors, in fair
+portion, to him, gained the power of dictating to the world and has
+gained an advance that cannot be measured. Watt and Arkwright and
+Stephenson and Crompton and their ilk, protected by their government
+and its patent laws, made their country the peaceful conqueror of the
+world. The story of the work of the inventor is a poem of mighty
+meaning and of wonderful deeds. The inventor proved himself a mightier
+magician than ever the world had seen.
+
+    "A creature he called to wait on his will,
+    Half iron, half vapor--a dread to behold;
+    Which evermore panted, and evermore rolled,
+    And uttered his words a millionfold."
+
+Such was the outcome of this grand modern "trust," a combination of
+the wisest legislation, the most brilliant invention, and the most
+wisely applied capital. There are "trusts" of which the outcome is
+most beneficent.
+
+Since the days of Watt, the improvement of the steam engine and the
+work of inventors has been confined to matters of detail. All the
+fundamental principles were developed by Watt and his predecessors and
+contemporaries and it only was left to his successors to find the best
+ways of carrying them into effect. But these matters of detail have
+been found to involve opportunities to make enormous strides in the
+direction of securing improved efficiency of the machine. The further
+application of the principle which led Watt to his greatest
+inventions; of the principle, keep the cylinder as hot as the steam
+which enters it, of that which he enunciated relative to the advantage
+of expanding steam, and of that affecting the regulation of the
+machine; have reduced the costs of steam and of fuel to a small
+fraction of their earlier magnitude. One ton of engine to-day does the
+work of eight or ten in the time of Watt: one pound of fuel or of
+steam gives to-day ten times the power then obtained from it. A
+steamship now crosses the Atlantic in one-eighth the time required by
+the famous "liner" of the "Black Ball Line." The wastes of the engine
+have been brought down from above eighty per cent. to eight; and a
+half-ounce of fuel on board ship will now transport a ton of cargo
+over a mile of ocean.
+
+FREDERICK E. SICKELS gave us the first practicable form of expansion
+gear in 1841; GEORGE H. CORLISS gave a new type of engine of marvelous
+perfection and economy in 1849; Noble T. Green, Wm. Wright and many
+less well known but no less meritorious inventors have since done
+their part in the transformation of the old engine of Watt into the
+modern wonder of concentrated and economical power, and marvel of
+accurate and beautiful design and workmanship. The "trip cut-off,"
+with reduced clearances, increased boiler pressure, higher rates of
+expansion, accelerated speeds of engine, better construction in all
+respects, as well as improved design, have enabled us to avail
+ourselves to the utmost of the principles of Watt, and our mills, our
+railways, our steamers and our fields, even, have gained almost as
+extraordinarily by these advances, since the days of the great
+inventor, as through his immediate labors.
+
+With the introduction of the new form of older energy, electricity,
+with the reduction of the lightning into thraldom, has now come a new
+impulse affecting all the industries. Through its mysterious, its
+still unknown action, steam now reaches out far from its own place,
+driving the electric car along miles of rail; giving light throughout
+all the country about it, turning night into day, and repressing crime
+while encouraging legitimate labor, reaching into distant chambers and
+every little workshop, to offer its powerful aid in all the
+distributed work of cities. Without the steam engine there would be
+little work available for electricity, but the appearance of this, the
+latest and most useful handmaid of steam, has given the engine work to
+do in an uncounted number of new fields, has called in the inventor
+once more to adapt steam to its new work. The "high-speed engine" is
+the latest form of the universal helper. And such has been the
+readiness and the intelligence of the contemporary inventor that we
+now have engines capable of turning their shafts three hundred
+rotations a minute and without a perceptible variation of velocity,
+whatever the change of load or the suddenness with which it is varied.
+In the days of Watt a fluctuation of five per cent. in speed was
+thought wonderfully small; in those of Corliss, the variation was
+restricted to two per cent. and we wondered at this unanticipated
+success. To-day, thanks to Porter and Allen, to Hartnell, to Hoadley,
+to Sims, to Thomson, to Sweet, to Ide, and to Ball, we have seen the
+speed fluctuation restricted to even less than one per cent. of its
+normal average.
+
+The inventors of the steam engine are, through their representatives
+of to-day, according to the statisticians, doing the equivalent of
+twelve times the work of a horse, for every man, woman and child on
+the globe. We have not less, probably, than a half million of miles of
+railway, transporting something over 150,000,000,000 of tons a mile a
+year. A horse is reckoned to haul a ton weight about six and a half
+miles, day by day, by the year together. In the United States, it is
+reckoned that the steam engine, on the railways alone, hauls a
+thousand tons one mile, for every inhabitant of the country, every
+year, or, if it is preferred to so state it, a ton a thousand miles.
+This is the way in which the East and the West are, by the inventors
+of the steam engine, enabled to help each other. This costs about $10
+each individual; it would require some 25 millions of horses to do the
+work, and would cost about $1,000 a family, which is more than twice
+the average family earnings.
+
+Dr. Strong, in that remarkable book, "Our Country," says: "One man, by
+the aid of steam, is able to do the work which required two hundred
+and fifty men at the beginning of the century. The machinery of
+Massachusetts alone represents the labor of more than 100,000,000 men,
+as if one-half of all the workmen of the globe had engaged in her
+service." And again: "Some thirty years ago, the power of machinery in
+the mills of Great Britain was estimated to be equal to 600,000,000
+men, or more than all the adults, male and female, of all mankind."
+Mr. Gladstone estimated that the aggregation of wealth on the globe
+during the whole period from the birth of Christ to that of Watt was
+equaled by the production in twenty years, at the middle of this
+century, with the aid of machinery driven by the fruit of the brain of
+the inventors of the steam engine. We may probably now safely estimate
+the former quantity as rivaled in less than five years, while, since
+the birth of Watt and his engine, and the production of the spinning
+mule, the power loom, the cotton gin and our own patent system and its
+marvelous mechanism, all events of a century ago, we may estimate that
+they have, together, accomplished more in this period which we now
+celebrate than could have been done in a millenium of milleniums
+without these now subjected genii. But the power behind all these
+curious inventions and their work is that of steam. The steam engine
+even supplies power to the telegraph and transports words and thought
+as well as cotton bales and coal.
+
+And now what has this combination of legislation for private
+protection and public good, of a genius producing great inventions,
+and of the accumulated capital of earlier years, brought about?
+
+It has given us the best fruits of science in permanent possession.
+The study of science invariably aids, in a thousand ways, the progress
+of mankind. It gives us new conceptions of nature and of the
+possibilities of art; it promotes right ways of work and of study; it
+teaches the inventor and the discoverer how most surely and promptly
+to gain their several ends, it gives the world the results of all
+acquired knowledge in concrete form. This one instance which we are
+now especially interested in contemplating has performed more
+wonderful miracles than ever Aladdin's genii attempted. One man, with
+a steam engine at his hand, turns the wheels of a great mill, drives
+forty thousand spindles, applies a thousand horse power to daily work
+in the spinning of threads, the weaving of cloth, the impulsion of a
+steamboat, or the drawing of great masses of hot iron into finest
+wire. This puny creature, his mind in his finger tips, exerts the
+power of ten thousand men, working with muscle alone, and, aided by a
+handful of women, boys and girls, clothes a city. A half dozen men in
+the engine room of an ocean steamer, with a hundred strong laborers in
+the boiler room and on deck, transports colonies and makes new
+nations, brings separated peoples together, unites countries on
+opposite sides of the globe, brings about easy exchanges between pole
+and equator. One man on the footboard of the locomotive, one man
+shoveling into the furnaces the black powder that incloses the energy
+stored in early geological ages, a half dozen men mounted on the long
+train of following vehicles, combine to bring to the mill girl in
+Massachusetts, the miner in Pennsylvania, the sewing woman, and the
+wealthy merchant, her neighbor in New York, the flour made in
+Minnesota from the grain harvested a few weeks earlier in Dakota. All
+the world is served faithfully and efficiently by this unimaginable
+power, this product of the brain of the inventor, protected by the
+law, stimulated and aided by the capital that it has itself almost
+alone produced.
+
+And thus have the inventors of the steam engine set in motion and
+placed at the disposal of mankind for every form of useful work all
+the great forces of nature; thus Hero of Alexandria touched the then
+concealed spring which called all the genii of earth, fire, water and
+air to do the bidding of the race. Thus Papin, Worcester, Newcomen,
+Watt, and Corliss and others of our own contemporaries, have applied
+the genii to their task of leveling mountains, traversing seas,
+continents, and the depths of the earth, building ships, locomotives,
+hamlets and cities, cottages and palaces, turning the spindle,
+operating the loom, and setting motion and giving energy to every
+machine, doing the work of thousands of millions of men, converting
+barbarism into civilization, giving necessaries of life in profusion,
+comforts in plenty, and luxuries in superabundance.
+
+Aiding and working hand in hand with those other genii of progress,
+the inventors of the printing press and of the telegraph, the
+telephone, and the electric railway, of the modern system of textile
+manufactures, of iron and steel making, of the mowing machine and the
+harvester, they have compressed into two centuries the progress of a
+millennium, destitute of their aid. Every step taken under their
+stimulus, and with their help, is a step toward a higher life for all,
+intellectually and morally as well as physically; every advance in the
+improvement of their work is a gain to every man, woman, and child;
+every improvement of the steam engine is a help to the whole world.
+This progress makes the day of the extinction of the system now
+grinding the populations of the earth into the ground, the day of the
+abolition of armies and the restoration to the people of that freedom
+which characterized the times of the patriarchs, and of the
+restoration of the rights of the citizen to his own time and strength
+and producing power, perceptibly nearer.
+
+When this final revolution shall have been accomplished, and when all
+the world has settled down to the steady and undisturbed work of
+production by daily and regular labor, aided by the genii of steam, of
+electricity, of all nature, combined for good, the results of the
+intellectual activity of the inventors of the steam engine will be
+fully seen. Then no monument will be required to keep green the memory
+of Watt, Corliss, or any other of these great men, but it will be said
+of them, as of Sir Christopher Wren in the epitaph in St. Paul's:
+"Seek you a monument, look about you!" Every wreath of steam rising to
+the heavens from factory, mill or workshop will be a reminder of Hero
+of Alexandria, every mine will possess a memorial to Papin, Worcester
+and Savery; every steamship will bring into grateful memory Fitch and
+Stevens, and Bell and Fulton; thousands of locomotives, crossing the
+continents, will perpetuate the thought of the Stephensons and their
+colleagues in the introduction of the railway; the hum of millions of
+spindles and the music of the electric wire will tell of the work of
+Corliss and his contemporaries and successors who made these things
+possible, and all kingdoms and races, all nations, will revere the
+name of James Watt, the genius to whom the world is most indebted for
+the beginnings of all this later and grander civilization which has
+converted the slow progress of earlier centuries into the meteor-like
+advance of to-day toward a future as grand and as mighty and as noble
+as humanity shall choose to make it.
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED HAND CAR.
+
+
+[Illustration]
+
+In the accompanying illustration we show a new design of hand car,
+being introduced by the Courtright Manufacturing Co., of Detroit. It
+will be seen that the apparatus for propelling the car is very
+different from the mechanism generally used. An upright framework
+secured to the platform carries a large sprocket wheel, which is
+connected to a smaller one upon one of the axles by means of a chain.
+The larger sprocket wheel is rotated by means of a triangular shaped
+lever attached at the lower corner to the crank of the sprocket wheel
+and having a handle at each of its upper corners. It is hinged upon a
+fulcrum which slides upon the two vertical rods shown in the
+illustration. It will be seen that this gives a peculiar movement to
+the handles by which the operators propel the car, but it has been
+found that the motion is an excellent one, and it is claimed that a
+higher speed can be obtained with the mechanism here shown than with
+any other now in use. There is practically no dead center, as in the
+case where the ordinary crank and lever is used. A number of leading
+roads have given the car a trial, and being well satisfied it, have
+given orders for more. The company claim that a car with 20 in. wheels
+can easily be made to attain a speed of 15 miles an hour by two
+men.--_Railway Review_.
+
+       *       *       *       *       *
+
+
+
+
+THE CONIC SECTIONS.
+
+By Prof. C.W. MACCORD, Sc.D.
+
+
+In Fig. 1 let D be a given point, and O the center of a given circle,
+whose diameter is FG. Bisect DF at A. Also about D describe an arc
+with any radius DP greater than DA, and about O another arc with a
+radius OP = DP + FO, intersecting the first arc at P, then draw PD,
+and also PO, cutting the circumference of the given circle in L. Since
+PD = PL, and DA = AF, it is evident that by repeating this process we
+shall construct a curve PAR, which satisfies the condition that _every
+point in it is equally distant from a given point and from the
+circumference of a given circle_. Since PO-PD = LO, and AO-AD = FO,
+this curve is one branch of the hyperbola of which D and O are the
+foci.
+
+[Illustration: FIG. 1]
+
+Bisect DG at B, then about D describe an arc with any radius DQ
+greater than DB, and about O another are with radius OQ = DQ-FO; draw
+from Q the intersections of these arcs, the line QD, and also QO,
+producing the latter to cut the circumference in E. By this process we
+may construct the curve QBZ, each point of which is also equally
+distant from the given point D, and from the concave instead of the
+convex arc of the given circumference. The difference between QD and
+QO being constant and equal to FO, and AB being also equal to FO, this
+curve is the other branch of the same hyperbola, whose major axis is
+equal to the radius of the given circle.
+
+The tangent at P bisects the angle DPL, and is perpendicular to DL,
+which it bisects at a point I on the circumference of the circle whose
+diameter is AB, the major axis, the center being C, the middle point
+of D O. As P recedes from A, it is evident that the angles P D L, P L
+D, will increase, until D L assumes the position D T tangent to the
+given circle, when they will become right angles. P will therefore be
+infinitely remote, and the point I having then reached t, where D T
+touches the smaller circle, C t S will be an asymptote to the curve.
+This shows that the measurements from the convex arc, for the
+construction of A P, are made only from the portion F T of the given
+circumference.
+
+In the diagram the point Q is so chosen that D L produced passes
+through E, so that Q J, the tangent at Q, is parallel to P I. It will
+thus be seen that the measurements from the concave arc, for the
+construction of B Q, are confined to the portion G T of the given
+circumference. As D L E rises, the points P and Q recede from A and B,
+the points L and E approach each other, finally coinciding at T; at
+this instant I and J fall together at t, so that S S is the common
+asymptote to A P and B Q.
+
+In Fig. 2 the given point D lies within the circumference of the given
+circle. Bisect D F at A, and D G at B; about D describe an arc with
+any radius D P greater than D A, and about O another, with radius O P
+= O F--D P, these arcs intersect in P, and producing O P to cut the
+circumference in L, we have P D = P L. Similarly E D = E H, U D = U W,
+etc. And since P D + P O = L P + P O, D E + E O = H E + E O, and so
+on, the curve is obviously the ellipse of which the foci are D and O,
+and the major axis is A B = F O, the radius of the given circle.
+
+[Illustration: FIG 2.]
+
+If, as in Fig. 3, the given point be made to coincide with the center
+of the circle, the ellipse becomes a circle with diameter A B = F O.
+But if the point be placed upon the circumference, as in Fig. 4, the
+ellipse will reduce to the right line A B coinciding with F O.
+
+[Illustration: FIGS 3, 4, 5, 6.]
+
+In this case we may also apply the same process as in Fig. 1; D T
+becomes a tangent at D to the circumference, and the asymptotes
+coincide with the axis of the hyperbola, of which one branch reduces
+to the right line A P extending from A to infinity on the left, and
+the other reduces to the right line B G Q, extending from B to
+infinity on the right.
+
+If the circle be reduced to a point, as in Fig. 5, the resulting locus
+is a right line perpendicular to and bisecting D O. If on the other
+hand the diameter of the given circle be infinite, the circumference,
+as in Fig. 6, becomes a right line perpendicular to the axis at F, and
+the curve satisfies the familiar definition of the parabola, D E being
+equal to E H, D P equal to P L, and so on.
+
+In Fig. 7, as in Fig. 1, DT is tangent at T to the given circle whose
+center is O, and at t to the circle about C whose diameter is AB, the
+major axis. Since DTO is a right angle, T lies upon the circumference
+of the circle whose center is C, and diameter DO; this circle cuts the
+asymptote SCS at M and N. The semi-conjugate axis is a mean
+proportional between D A and AO; now drawing TM and TN, it is seen
+that Tt is that mean proportional; and a circle described about C with
+that radius will be tangent to TO. DT, then, is the radius of the
+circle to be described about the focus of the conjugate hyperbola for
+its construction according to the enunciation first given: and we
+observe that DT and TO are supplementary chords in the circle about C
+through D and O. The conjugate foci must therefore lie upon this
+circumference, at D' and O'; and since D'O' is perpendicular to DO,
+D'T will be perpendicular and T'O' will be parallel to SCS.
+
+[Illustration: FIG 7.]
+
+Now as TO increases, T'O' will diminish, until, when TO equals DO,
+T'O' will vanish and with it Ct'; and at this crisis, the case is the
+same as in Fig. 4; but the conjugate hyperbola logically reduces to
+_two_ right lines, extending from C to infinity on the right and left.
+As indeed it should from the familiar construction, since the
+distances from D' and O' to any point on the horizontal axis being
+equal, their difference is constant and equal to zero.
+
+It appears, then, that a conic section may be defined as the locus of
+a point which is equally distant from a given point and from the
+circumference of a given circle. Boscovich defines it as the locus of
+a point so moving that its distances from a given point and from a
+given right line shall have a constant ratio.
+
+The latter definition involves the conceptions of a rectilinear
+directrix, and a varying ratio in the cases of the different curves,
+this ratio being unity for the parabola, less for the ellipse, and
+greater for the hyperbola. The former involves the conception of a
+circular directrix with a ratio equal to unity in all cases; and the
+two definitions become identical in the construction of the parabola,
+which is in fact the only curve of which a clear idea is given by
+either of them. That of Boscovich has been given a prominence far in
+excess of its merits, being made the foundation for the discussion of
+these important curves, and this in a textbook whose preface contains
+the following true and emphatic statement, viz.:
+
+    "The abstract nature of a ratio, and the fact that it is a
+    compound concept, peculiarly unfit it for elementary
+    purposes."
+
+The definition herein set forth has not been given in any treatise on
+the subject, so far as we have been able to ascertain. And it is
+presented with the distinctly expressed hope that it never will be,
+except as a mere matter of abstract interest.
+
+Of this it may, like the other, possess a little, but both have the
+great disadvantage that, except in relation to the parabola, the idea
+which they convey to the mind of the curves to which they relate, if
+indeed they convey any at all, is most obscure and indirect; and of
+practical utility neither one can claim a particle.
+
+       *       *       *       *       *
+
+
+
+
+TABLE OF ATOMIC WEIGHTS.
+
+(Issued December 6, 1890.)
+
+
+By request of the Committee of Revision and Publication of the
+Pharmacopoeia of the United States of America, Prof. F.W. Clarke,
+chief chemist of the United States Geological Survey, has furnished a
+table of atomic weights, revised upon the basis of the most recent
+data and his latest computations. The committee has resolved that this
+table be printed and furnished for publication to the professional
+press. The committee also requests that all calculations and
+analytical data which are to be given in reports or contributions
+intended for its use or cognizance be based upon the values in the
+table. It would be highly desirable that this table be adopted and
+uniformly followed by chemists in general, at least for practical
+purposes, until it is superseded by a revised edition. It would only
+be necessary for any author of a paper, etc., to state that his
+analytical figures are based upon "Prof. Clarke's table of atomic
+weights of December 6, 1890," or some subsequent issue.
+
+This table represents the latest and most trustworthy results, reduced
+to a uniform basis of comparison, with oxygen=16 as starting point of
+the system. No decimal places representing large uncertainties are
+used. When values vary, with equal probability on both sides, so far
+as our present knowledge goes, as in the case of cadmium (111.8 and
+112.2), the mean value is given in the table.
+
+The names of elements occurring in pharmaceutical, medicinal,
+chemicals, are printed in italics[1]:
+
+[Transcriber's Note 1: ITALICS represented by surrounding with "_".]
+
+
+  Name.           Symbol.  Atomic Weight.
+
+_Aluminum_.        _Al_        27.
+_Antimony_.        _Sb_       120.
+_Arsenic_.         _As_        75.
+_Barium_.          _Ba_       137.
+_Bismuth_.         _Bi_       208.9
+_Boron_.           _B_         11.
+_Bromine_.         _Br_        79.95
+Cadmium.            Cd        112.
+Caesium.            Cs        132.9
+_Calcium_.         _Ca_        40.
+_Carbon_.          _C_         12.
+_Cerium_.          _Ce_       140.2
+_Chlorine_.        _Cl_        35.45
+_Chromium_.       _Cr_         52.1
+Cobalt.             Co         59.
+Columbium.[1]       Cb         94.
+_Copper_.          _Cu_        63.4
+Didymium.[2]        Di        142.3
+Erbium.             Er        166.3
+Fluorine.           F          19.
+Gallium.            Ga         69.
+Germanium.          Ge         72.3
+Glucinum.[3]        Gl          9.
+_Gold_.            _Au_       197.3
+_Hydrogen_.        _H_          1.007
+Indium.             In        113.7
+_Iodine_.          _I_        126.85
+Iridium.            Ir        193.1
+_Iron_.            _Fe_        56.
+Lanthanum.          La        138.2
+_Lead_.            _Pb_       206.95
+_Lithium_.         _Li_         7.02
+_Magnesium_.       _Mg_        24.3
+_Manganese_.       _Mn_        55.
+_Mercury_.         _Hg_       200.
+_Molybdenum_.      _Mo_        96.
+Nickel.             Ni         58.7
+_Nitrogen_.        _N_         14.03
+Osmium.             Os        191.7
+_Oxygen_.[4]       _O_         16.
+Palladium.          Pd        106.6
+_Phosphorus_.      _P_         31.
+Platinum.           Pt        195.
+_Potassium_.       _K_         39.11
+Rhodium.            Rh        103.5
+Rubidium.           Rb         85.5
+Ruthenium.          Ru        101.6
+Samarium.           Sm        150.
+Scandium.           Sc         44.
+Selenium.           Se         79.
+_Silicon_.         _Si_        28.4
+_Silver_.          _Ag_       107.92
+_Sodium_.          _Na_        23.05
+Strontium.          Sr         87.6
+_Sulphur_.         _S_         32.06
+Tantalum.           Ta        182.6
+Tellurium.          Te        125.
+Terbium.            Tb        159.5
+Thallium.           Tl        204.18
+Thorium.            Th        232.6
+Tin.                Sn        119.
+Titanium.           Ti         48.
+Tungsten.           W         184.
+Uranium.            U         239.6
+Vanadium.           V          51.4
+Yterbium.           Yb        173.
+Yttrium.            Yt         89.1
+_Zinc_.            _Zn_        65.3
+Zirconium.          Zr         90.6
+
+--_Am. Jour. Pharm._
+
+[Footnote 1: Has priority over niobium.]
+
+[Footnote 2: Now split into neo-and praseo-didymium.]
+
+[Footnote 3: Has priority over beryllium.]
+
+[Footnote 4: Standard, or basis of the system.]
+
+       *       *       *       *       *
+
+
+
+
+THE TANNING MATERIALS OF EUROPE.
+
+
+The tanning materials of Europe are of an altogether different type
+from those of the United States. The population is so dense that the
+quantity of home materials produced is not nearly proportionate to the
+amount consumed, and consequently they must draw upon surrounding
+lands for their supply. The vegetation of these adjacent countries is
+of a much more tropical nature, and it naturally follows that the
+tanning materials are also of a different species.
+
+Tanning materials may be divided into two great classes, viz.:
+Physiological and pathological.
+
+
+PHYSIOLOGICAL.
+
+The first class includes those tannins which are the results of
+perfectly natural or normal growth, and a growth necessary to the
+development of vegetation, for instance, bark, sumac, etc., whereas
+the second class contains those which are the results of abnormal
+growth, caused by diseases, stings of insects, etc. An example of this
+is the gall. Both of these classes are used to a great extent in
+Europe, while only the first division is in general use in the United
+States. We will first consider the physiological tannins.
+
+
+_Oak Bark._--This material was, is, and will be for some time to come
+the main tanning material in use here in Europe. The advantages of the
+oak tannage are as fully appreciated here as in the United States. The
+European oak gives a light colored, firm leather, with good weight
+results, is comparatively cheap and of an excellent quality. The
+varieties are numerous, each country having its own kind. Those in
+most general use are:
+
+_Spiegel Rinde_ (mirror bark).--This bark is well distributed
+throughout Europe, and is peeled when the tree has attained a growth
+of from 12 to 24 years. It is marketed in three grades.
+
+_Reitel Rinde_--Is obtained from the same tree as the spiegel rinde,
+but after the tree has attained a growth of from 25 to 40 years.
+
+_Alte Pische_ (old oak).--Obtained from the aged tree. It is not as
+valuable as the younger bark, and consequently brings a much lower
+price.
+
+Spiegel rinde may be judged by small warts which appear on the shining
+surface of the bark. The presence of a great number of these, as a
+rule, indicates a high tannin percentage.
+
+Bosnia has fine oak trees, the bark containing 10 to 11 per cent.
+tannin.
+
+Bohemia has the _trauben eiche_ (grape oak).
+
+France uses the kirmess oak, which grows in the south of that country
+and in northern Africa. Two grades are made, viz., root and trunk.
+
+Tyrol has the evergreen oak--12 to 13 per cent. tannin.
+
+Sardinia possesses a cork oak, which yields 13 to 14 per cent.
+
+White oak is found throughout Europe, yielding 10 per cent. The price
+of oak bark varies a great deal. The assortment is much more strict
+than in the United States. In Austria it brings 4 to 5 fl., equal to
+$1.60 to $2 per kilo. (224 lb.); in Germany, 11 to 16 marks per 100
+kilos.[1]
+
+[Footnote 1: In the principal districts in America, removed from the
+cities, the price of oak bark is about $4 to $6 per cord or per ton
+of 2,240 lb. The hemlock bark, which gives a sole leather just as
+thoroughly tanned, but of a darker and reddish color, costs the
+larger tanners from $3 to $4 a cord.]
+
+The above mentioned varieties are all used for both upper and sole
+leather. In Germany a great deal of upper leather is pure oak tannage,
+but one seldom finds a pure oak tanned sole leather; it is almost
+always in combination with other tannics.
+
+
+_Pine Bark_--Is well distributed and is a very important tanning
+material. It bears the same relation to oak bark here as does hemlock
+in America, but its effects are quite different from hemlock. The best
+Austrian sorts are those of Styria and Bohemia, but that of Karuthen
+is also of good quality. The German pine comes from Thuringia to a
+great extent. The countries that consume the greatest amount of pine
+bark are Austria, Germany, Russia and Italy. The tannin contained
+varies from 5 to 16 per cent. Its use is almost wholly confined to the
+handlers, as its weight returns are not so satisfactory as oak or
+valonia. In case it should be used for layers it is always in
+combination with some better weight-giving tannic. For upper leather
+its use is limited.
+
+The bark is always peeled from the felled tree, and often the woodman
+accepts the bark in part payment for his labor; he then sells the bark
+to the tanner or agents who go about the country collecting bark. It
+is generally very nicely cleaned. I would here like to correct a
+mistake which tanners often make in their estimations of the value of
+barks. A tanner usually buys the bark of southern-grown trees in
+preference to that of trees grown in northern countries, as it is a
+common idea that southern vegetation contains more tannin than that of
+the north. This is a fallacy, as has not only been proved by careful
+analyses, but may also be found to be an incorrect conclusion after a
+moments' thought. Those trees which flourish in southern countries
+grow very rapidly, and as tannin is necessary to the development of
+leaf structure, etc., it is absorbed to a greater extent than is the
+case with the slower-growing tree of the north. The tannin contained
+in the sap does not increase in the same ratio as does the rapid
+growth, and it follows that the remainder in the bark is less than in
+the tree of slower growth.
+
+
+_Birch Bark_--Is at home in Russia, Norway, and Sweden. It is used for
+both upper and sole leather, but seldom alone. The bark is usually
+peeled from the full grown tree, and contains 4 to 9 per cent. tannin.
+
+
+_Willow Bark_--May also be found in the above mentioned countries and
+also in Germany. This material is used for both upper and sole
+leather, and contains 6 to 9 per cent. tannin. It is a very delicate
+material to use, as its tannin decomposes rapidly.
+
+
+_Erlen Rinde_--Is also a native of Germany, but is not used to any
+great extent. The same may be said of the larch, although this variety
+is also to be met with in Russia.
+
+
+_Mimosa Bark_--Is obtained from the acacia of Australia. It is a
+favorite in England. The varieties are as follows: Gold wattle, silver
+wattle (blackwood, lightwood), black wattle, green wattle. The gold
+wattle is a native of Victoria. Its cultivation was tried as an
+experiment in Algeria and met with some success. The trees are always
+grown from seeds. These seeds are laid in warm water for a few hours
+before sowing. The acacia may be peeled at eight years' growth and
+carries seeds. The Tasmania bark is very good; that from Adelaide
+likewise good.
+
+Sydney does not produce so good an article, but Queensland better. The
+bark is marketed in the stick, ground or chopped.
+
+Madagascar and the Reunion Islands have also a mimosa bark.
+
+The mimosa barks give a reddish colored leather, pump well and contain
+a high tannin percentage, 10 to 35 per cent.
+
+
+Now we will consider the fruit tanning materials.
+
+Valonia may truly be called one of the most generally used tanning
+agents at present employed in Europe. All countries consume it more or
+less. Valonia was first used in England about the beginning of this
+century. A few years later Germany began using it, and still later
+Austria introduced it. It is the fruit of the oak tree and is
+obtainable in Asia Minor and the adjacent islands. In form it
+resembles the American acorn, but in size it nearly trebles it. The
+fruit may be divided into two parts, namely, the cup and acorn, and
+the cup again divided into trillor and inner cup. The acorn only
+contains 10 per cent. tannin, whereas the cup contains from 25 to 40
+per cent.
+
+The percentage depends altogether upon the time of harvesting and the
+place of growth. The best valonia is derived from Smyrna, and is
+naturally the highest priced article. Valonia is worth from 22 to 28
+florins ($9 to $11) per 100 kilos. (224 pounds) at present. The other
+provinces and islands from which it is obtainable are Demergick,
+Govalia, Idem, Ivalzick, Troy (this is the best); Metelino Island, the
+vicinity of Smyrna. The material sold in three grades--prime, mazzano;
+seconds, una aqua; thirds, skart.
+
+The product of Smyrna generally averages:
+
+                       Tons.           Price.
+    Prime.        2,000 to  3,000      28 florins.
+    Seconds.      5,000 to 10,000      25    "
+    Thirds.      20,000 to 30,000      22    "
+
+The _Metilino_ valonia is a product of a neighboring island, and is a
+very good article. It may be easily distinguished by its thin cup. It
+is harvested in September.
+
+The _Candia_ valonia is nearly as long as it is wide, in contrast to
+the Smyrna, which is much wider than long. The recent harvest showed a
+return of 800 to 1,000 tons, but no assortment is made. A grade called
+the Erstlige is sold, this being the first which has fallen to the
+ground before maturing.
+
+A peculiarity of the valonia is that it often strikes out a sort of
+sugar sweat, which gives the cup a less attractive appearance, but
+denotes the presence of large quantities of tannin.
+
+Valonia is used almost wholly for sole leather, either alone or in
+combination with pine or oak bark or knoppern and myrabolams. The
+union of valonia and knoppern is that in most general use. Valonia
+gives the leather a yellowish appearance, as it deposits a great deal
+of yellow bloom. The leather is very firm and of good wearing
+qualities. The weight results are also excellent, as will be seen
+below. To sole leather there are usually given from one to three
+layers of valonia. The demand for valonia is increasing more and more
+every year, and the present outlook does not indicate any relaxation
+of its popularity. Its use for upper leather is very limited.
+
+Myrabolams are mainly used in England and Austria, and give a nice
+light-colored leather, both upper and sole, although rarely used
+alone. Their main use is for dyeing purposes. They are indigenous to
+the East Indies.
+
+Sumac is so well known that treating of it is superfluous. Its use is
+very extensive, and it is a general favorite for light, fine leather,
+which is mostly used for colors.
+
+_Gambier_--Is in general use in England and to some extent in Germany.
+
+_Catechu_.--Obtained from India, resembles gambier greatly. Its use is
+almost wholly confined to England. It is also consumed by the silk
+manufacturers in preference to gambier, for weighting purposes.
+
+
+PATHOLOGICAL.
+
+We now leave the physiological class and take up those tanning
+materials included in the pathological class, or those of abnormal
+growth.
+
+
+_Galls_.--These are not consumed to any great extent at the present
+period, but formerly they were used quite extensively. The galls are
+found upon the leaves of the oak or sumac, etc. The direct cause of
+their growth is that a certain wasp (cynips galles) stings into the
+leaf and after depositing its egg, flies away. The egg develops into a
+larva and then into a full-fledged wasp, boring its way out of the
+gall which has served as a protection and nourisher. This accounts for
+the hole noticed in almost every gall. The different varieties include
+Aleppo. It is found upon the same trees as the valonia and contains 60
+to 75 per cent. tannin; Istrian galls, 32 per cent. tannin; Persian,
+28 to 29 per cent. tannin. Chinese galls, giving 80 to 82 per cent.
+tannin, are the results of the sting of a louse, and make a very
+light-colored leather. The dyers also use this material for coloring.
+
+
+_Knoppern_--Belongs to the family of galls, and is a most important
+factor of commerce in Austria. The knopper is generally found on the
+acorn or leaf of the oak tree. The greatest quantity is derived from
+the steel oak of Hungary. The tannin contained varies from 27 to 33
+per cent. Knoppern are not being used so much now as formerly, and
+consequently the amount harvested lessens from year to year. Its main
+use was and is in combination with valonia as layers for sole leather.
+Valonia gives better weight results than knoppern, and is replacing
+knoppern more and more every year. The combination of knoppern,
+valonia and myrabolams is also quite popular, and gives good results.
+Knoppern are seldom used alone, being generally combined with some
+other tannin. Austria is almost the only consumer at present, but
+Germany used it extensively formerly.
+
+
+_Bark and Wood Extracts_--Are becoming general favorites throughout
+Europe, partly because of their weight-giving qualities and partly as
+the transportation costs so little; they can be used to strengthen
+weak bark liquors.
+
+_Oak Extracts_--Are well liked, both wood and bark, and are used
+extensively. Slavonia furnishes a great deal of it.
+
+_Chestnut Oak Wood Extract_--Is manufactured in quantities, and easily
+finds purchasers.
+
+_Pine Bark Extract_--Is also consumed in goodly amounts.
+
+_Quebracho Wood Extract_.--The wood is shipped from Brazil to Hamburg
+and other ports, and the tannin extracted there. Hamburg furnishes
+quantities of it.
+
+_Hemlock Extract_--Is used in Russia, and seems to have taken a hold
+on the shoe buyers' fancies, as they now make imitations of it in
+color. The hemlock that is consumed is imported from America.
+
+
+As most leather is sold by weight in Europe, the leather manufacturers
+aim to obtain as good weight results as possible, and often, I am
+sorry to say, do so at the sacrifice of quality. This is common to
+both upper and sole leather. Sole leather is nine times out of ten
+given false weight by forcing entirely foreign substances into the
+leather, such as glucose, barium chloride, magnesium chloride, resins,
+etc. Glucose and resin are also used for weighting upper leather.
+Leather is also weighted with extracts by overtanning. Leather buyers
+have become very wary of late and do not purchase large quantities
+before an analysis is made of a fair sample.
+
+One more word before I close. The governments and private individuals
+in Europe cultivate and raise trees for both lumber and bark purposes.
+The forests are excellently cared for by efficient foresters, and the
+result is that the tanners obtain much cleaner and better bark, and of
+a very even quality. Would it not be a good idea if some individual,
+who would certainly earn the everlasting gratefulness of the tanners,
+would look into this matter, and see that not only the lumber side of
+our forest cultivation is not neglected, but that the bark also is
+preserved and cared for? Of course, we can obtain all the bark
+necessary at present and for some time to come, but the time will come
+when we shall certainly regret not having taken these steps, if the
+lumbermen and bark peelers go on devastating magnificent forests.
+Below will be found a table of weight results. Sole leather tanned
+with these materials gives for every 100 lb. green hide the following
+quantities of finished leather:
+
+                                     lb.
+  Oak bark                          48 to 54
+  "   extract                       55 to 56
+  Pine bark                         44 to 46
+  "   extract                       48 to 50
+  Willow                            45 to 46
+  Birch bark and oak extract        49 to 51
+  Quebracho wood and extract        48 to 49
+  Valonia                           52 to 56
+  Knoppern                          51 to 53
+  Myrabolams                        50
+  Knoppern, myrabolams and valonia  52 to 53
+  Hemlock                           55
+
+Specification of tanning materials used in different countries:
+
+_France_.
+Oak bark (kirmess).
+Sumac.
+Chestnut wood extract.
+Quebracho "     "
+Some gambier.
+
+_Italy_.
+Oak bark.
+Pine "
+Sumac.
+Valonia.
+
+_England_.
+Oak bark.
+Divi divi.
+Myrabolams.
+Valonia.
+Mimosa.
+Extracts { Oak bark and wood hemlock.
+Gambier.
+Cutch.
+
+_Germany and Austria_.
+Oak bark.
+Pine "
+Willow bark.
+Valonia.
+Knoppern.
+Myrabolams.
+         { Oak bark and wood.
+Extracts { Pine bark and wood.
+
+_Russia._
+Birch bark.
+Willow "
+Oak    "
+Pine   "
+Hemlock extract.
+
+
+_Norway and Sweden_.
+Birch bark.
+Willow "
+Oak    "
+
+                                      WALTER J. SALOMON.
+--_Shoe and Leather Reporter_.
+
+       *       *       *       *       *
+
+
+
+
+AN APPARATUS FOR HEATING SUBSTANCES IN GLASS TUBES UNDER PRESSURE.[1]
+
+[Footnote 1: Read at the meeting of the Chemical Section of the
+Franklin Institute held March 17, 1891.]
+
+By H. PEMBERTON, Jr.
+
+
+Chemists who do not happen to have in their laboratories oil or air
+baths for heating closed tubes can make an air bath at short notice
+from materials furnished by all dealers in steam fittings.
+
+_Order_:
+
+(1) One four-inch wrought iron pipe, eighteen inches out to out, with
+usual thread on each end. At about nine inches from either end this
+pipe is drilled and tapped for a one-inch nipple, in such a manner
+that a pipe introduced would pass, not on a line with the radius, but
+about half way between the axis of the four-inch pipe and its walls;
+in other words, it would be on a line with a chord of the circle.
+
+(2) One one-inch wrought iron nipple, two inches long, one-inch thread
+on one end.
+
+(3) Two four-inch malleable iron caps, drilled and tapped for a
+one-inch pipe.
+
+(4) One one-inch wrought iron pipe, twenty-four inches out to out,
+with a three-inch straight thread on each end.
+
+(5) Two one-inch iron caps. A hole, one-eighth of an inch in diameter,
+is drilled in the end of one of these caps.
+
+The above order can be given _literatim_, and will be understood by
+the dealer, who will furnish, at a trifling cost, the materials, cut
+and tapped as ordered.
+
+Fig. 1 shows how the whole is put together. The numbers on the figure
+correspond also to the numbers of the paragraphs of the order as given
+above.
+
+[Illustration: FIG. 1.]
+
+[Illustration: FIG. 2.]
+
+Fig. 2 is an end section. A cork is inserted in 2 and through it a
+thermometer, the bulb of which is on a level with the interior pipe.
+The whole is supported on a few bricks at either end, and is kept
+steady and in place by a couple of weights or half bricks. It is
+heated by one or two Bunsen burners, according to the temperature
+desired.--_Jour. Fr. Institute_.
+
+       *       *       *       *       *
+
+
+
+
+TESTING CEMENT.
+
+
+An improved method of testing Portland cement has been adopted by M.
+Deval, Chief Superintendent of Bridges and Roads, who has charge,
+under M. Saele, of the Public Works Laboratory of the City of Paris.
+The principal difference in M. Deval's method consists in the use of
+hot water for the period of hardening. The briquettes are made in the
+usual way, and of the ordinary size; and the cement to be tested is
+gauged with three times its weight of normal sand, and the smallest
+quantity of water possible. After preparation, the briquettes are
+allowed to harden in air for a period ranging from 24 hours for
+Portland cement to 30 days for certain slow-setting hydraulic limes.
+After this period, the samples are immersed in water kept at a
+temperature of 80° C., in which they remain for from two to seven
+days. The briquettes are then broken in the ordinary way. After
+careful comparisons of many varieties of cement hardened hot and cold,
+M. Deval finds that cold tests are fallacious, inasmuch as they may
+fail to detect bad material. Portland cement of good quality will not
+only stand water at 80° C., but will attain in seven days about the
+same strength as is reached in the cold after 28 days. The hot test
+therefore saves time. The hot test is an unfailing proof for free
+lime; cements containing this constituent betraying weakness, and
+cracking, swelling, and disintegrating in a very significant manner.
+This last result is regarded as a valuable quality of the new method
+of testing cement, the general effect of which appears to be to
+enhance the test value of really good cements, while depreciating
+those of an inferior character.
+
+       *       *       *       *       *
+
+
+THE SCIENTIFIC AMERICAN Architects and Builders Edition
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+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+803, May 23, 1891, by Various
+
+*** END OF THE PROJECT GUTENBERG EBOOK 13358 ***
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+<title>The Project Gutenberg eBook of Scientific American
+Supplement, May 23, 1891</title>
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+<!--
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+<div>*** START OF THE PROJECT GUTENBERG EBOOK 13358 ***</div>
+
+<p class="ctr"><a href="./images/title.png"><img src="images/title-th.jpg" alt=""></a></p>
+<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 803</h1>
+<h2>NEW YORK, May 23, 1891</h2>
+<h4>Scientific American Supplement. Vol. XXXI., No. 803.</h4>
+<h4>Scientific American established 1845</h4>
+<h4>Scientific American Supplement, $5 a year.</h4>
+<h4>Scientific American and Supplement, $7 a year.</h4>
+<hr />
+<table summary="Contents" border="0" cellspacing="5">
+<tr>
+<th colspan="2">TABLE OF CONTENTS.</th>
+</tr>
+<tr>
+<td valign="top">I.</td>
+<td><a href="#ast-1">
+ASTRONOMY.&mdash;The Great Equatorial of the Paris Observatory.&mdash;
+      The new telescope recently put in use in Paris.&mdash;Description of
+      the instrument and of its effects.&mdash;3 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">II.</td>
+<td><a href="#chem-1">
+CHEMISTRY.&mdash;An Apparatus for Heating Substances in Glass
+      Tubes under Pressure.&mdash;By H. PEMBERTON, Jr.&mdash;A simple apparatus
+      for effecting this purpose, avoiding risk of personal injury.&mdash;
+      2 illustrations</a></td>
+</tr>
+<tr>
+<td></td>
+<td><a href="#chem-2">
+ Table of Atomic Weights.&mdash;A revised table of atomic weights,
+      giving the results of the last determinations, and designed for
+      every-day use</a></td>
+</tr>
+<tr>
+<td></td>
+<td><a href="#chem-3">
+Testing Cement.&mdash;A laboratory process for testing Portland cement</a></td>
+</tr>
+<tr>
+<td valign="top">III.</td>
+<td><a href="#ce-1">
+CIVIL ENGINEERING.&mdash;The Compressed Air System of Paris.
+      &mdash;An elaborate review of this great installation for the transmission
+      of power.&mdash;The new compressed air station, with full details
+      of performances of apparatus, etc.&mdash;10 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">IV.</td>
+<td><a href="#ent-1">
+ENTOMOLOGY.&mdash;Report on Insects.&mdash;Continuation of this report
+      on noxious insects.&mdash;Their habits and how to cope with them.
+      &mdash;18 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">V.</td>
+<td><a href="#flo-1">
+FLORICULTURE.&mdash;Lily of the Valley.&mdash;Practical notes on the
+      cultivation of this popular flower.&mdash;How to raise it and force the
+      growth
+</a></td>
+</tr>
+<tr>
+<td valign="top">VI.</td>
+<td><a href="#math-1">
+MATHEMATICS.&mdash;The Conic Sections.&mdash;By Prof. C.W.
+      MACCORD.&mdash;Examination of the four conic sections with a general
+      definition applicable to all.&mdash;6 illustrations </a></td>
+</tr>
+<tr>
+<td valign="top">VII.</td>
+<td><a href="#me-1">
+MECHANICAL ENGINEERING.&mdash;The Builders of the Steam
+      Engine&mdash;The Founders of Modern Industries and Nations.&mdash;By Dr.
+      R.H. THURSTON.&mdash;Prof. Thurston's address before the Centennial
+      Celebration of the American Patent System at Washington,
+      D.C.&mdash;The early history of the steam engine and its present position
+      in the world
+</a></td>
+</tr>
+<tr>
+<td valign="top">VIII.</td>
+<td><a href="#misc-1">
+MISCELLANEOUS.&mdash;The Breeds of Dogs.&mdash;Popular description
+      of the different breeds of dogs most affected by amateurs.&mdash;6.
+      illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">IX.</td>
+<td><a href="#nav-1">
+NAVAL ENGINEERING.&mdash;Modern Armor.&mdash;By F.R. BRAINARD.&mdash;The
+      development of modern ship armor, from laminated
+      sandwiched and compound types to the present solid armor.&mdash;9 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">X.</td>
+<td><a href="#pisc-1">
+PISCICULTURE.&mdash;Restocking the Seine with Fish.&mdash;The introduction
+      of 40,000 fry of California trout and salmon, designed to restock
+      the Seine, depopulated of fish by explosions of dynamite
+      used in breaking up the ice.&mdash;1 illustration</a></td>
+</tr>
+<tr>
+<td valign="top">XI.</td>
+<td><a href="#rr-1">
+RAILWAY ENGINEERING.&mdash;Improved Hand Car.&mdash;A novelty
+      in the construction of hand cars, avoiding the production of a
+      dead center.&mdash;1 illustration</a></td>
+</tr>
+<tr>
+<td valign="top">XII.</td>
+<td><a href="#tec-1">
+TECHNOLOGY.&mdash;The Tanning Materials of Europe.&mdash;The natural
+      tanning materials and pathological or abnormal growth tanning
+      materials described and classified, with relative power</a></td>
+</tr>
+</table>
+<hr />
+
+<a name="ast-1"></a><h2>THE GREAT EQUATORIAL OF THE
+PARIS OBSERVATORY.</h2>
+
+<p>The great instrument which has just completed
+the installation of our national observatory
+is constructed upon the same principle as
+the elbowed equatorial, 11 in. in diameter, established
+in 1882, according to the ingenious
+arrangement devised as long ago as 1872, by
+Mr. Loewy, assistant director of the Paris Observatory.</p>
+
+
+<p>We shall here recall the fact that the elbowed
+equatorial consists of two parts joined at right
+angles. One of these is directed according to
+the axis of the world, and is capable of revolving
+around its own axis, and the other, which
+is at right angles to it, is capable of describing
+around the first a plane representing the celestial
+equator. At the apex of the right angle
+there is a plane mirror of silvered glass inclined
+at an angle of 45 deg. with respect to the
+optical axis, and which sends toward the ocular
+the image coming from the objective and already
+reflected by another and similar plane
+mirror. The objective and this second mirror
+(which is inclined at an angle of 45 deg.) are
+placed at the extremity of the external part of
+the tube, and form part of a cube, movable
+around the axis of the instrument at right
+angles with the axis of the world. The diagram
+in Fig. 3 will allow the course of a luminous
+ray coming from space to be easily
+understood. The image of the star, A, toward
+which the instrument is directed, traverses the
+objective, B C, is reflected first from the mirror, B D,
+and next from the central mirror, E F, and finally
+reaches O, at the ocular where the observer is stationed.</p>
+
+<p class="ctr">
+<img src="images/1-fig3.png" alt="FIG. 3. COURSE OF LUMNIOUS RAY" title="">
+<br clear="all" />FIG 3.&mdash;DIAGRAM SHOWING THE COURSE OF
+A LUMINOUS RAY IN THE GREAT EQUATORIAL.</p>
+
+<p>This new equatorial differs from the first model by
+its much larger dimensions and its extremely remarkable
+mechanical improvements. The optical part,
+which is admirably elaborated, consists of a large astronomical
+objective 24 in. in diameter, and of a photographic
+objective of the same aperture, capable of
+being substituted, one for the other, according to the
+nature of the work that it is desired to accomplish by
+the aid of this colossal telescope, the total length of
+which is 59 ft. The two plane mirrors which complete
+the optical system have, respectively, diameters of 34
+in. and 29 in. These two magnificent objectives and
+the two mirrors were constructed by the Brothers
+Henry, whose double reputation as astronomers and
+opticians is so universally established. The mechanical
+part is the successful work of Mr. Gautier, who has
+looked after every detail with the greatest care, and
+has thus realized a true <i>chef d'oeuvre</i>. The colossal instrument,
+the total weight of which is 26,400 lb., is
+maneuvered by hand with the greatest ease. A clockwork
+movement, due to the same able manufacturer, is
+capable, besides, of moving the instrument with all the
+precision desirable, and of permitting it to follow the
+stars in their travel across the heavens. A star appearing
+in the horizon can thus be observed from its
+rising to its setting. The astronomer, his eye at the
+ocular, is always conveniently seated at the same place,
+observing the distant worlds, rendered immovable, so
+to speak, in the field of the instrument. For stars
+which, like the moon and the planets, have a course
+different from the diurnal motion, it is possible to
+modify the running of the clockwork, so that they can
+thus be as easily followed as in the preceding case.
+Fig. 1 gives a general view of the new installation, for
+which it became necessary
+to build a special edifice 65
+ft. in height on the ground
+south of the observatory
+bordering on the Arago
+Boulevard. A large movable
+structure serves for
+covering the external part
+of the instrument. This
+structure rests on rails,
+upon which it slides toward
+the south when it is
+desired to make observations.
+It will be seen from
+the figure how the principal
+axis of the instrument
+rests upon the two masonry
+pillars, one of which is
+49 ft. and the other 13 ft.
+in height.</p>
+
+<p class="ctr"><a href="./images/1-fig1.png">
+<img src="images/1-fig1-th.jpg" alt="FIG 1." title="">
+</a><br clear="all" /> FIG 1.&mdash;THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.</p>
+
+<p> The total cost of the
+pavilion, rolling structure,
+and instrument (including
+the two objectives) will
+amount to about $80,000
+after the new equatorial
+has been provided with the
+scientific apparatus that
+necessarily have to accompany
+it for the various
+and numerous applications
+to which the use of
+it will give rise.</p>
+
+<p class="ctr"><a href="./images/1-fig2.png">
+<img src="images/1-fig2-th.jpg" alt="FIG 2.--OCULAR OF THE GREAT EQUATORIAL." title=""></a>
+<br clear="right" /> FIG 2.&mdash;OCULAR OF THE GREAT EQUATORIAL.</p>
+
+<p>Fig. 2 shows us the room
+in the observatory in
+which the astronomer,
+seated in his chair, is completely
+protected against
+the inclemencies of the
+weather. Here, with his eye applied to the ocular, he
+can, without changing position (owing to all the
+handles that act at his will upon the many transmissions
+necessary for the maneuvering), direct his instrument
+unaided toward every point of the heavens with
+wonderful sureness and precision. The observer has
+before him on the same plane two divided circles, one
+of which gives the right ascensions and the other the
+declinations, and which he consults at each observation
+for the exact orientation of the equatorial.
+</p>
+
+<p>All the readings are done by the aid of electric lamps
+of very small dimensions, supplied by accumulators,
+and which are lighted at will. Each of these lamps is
+of one candle power; two of them are designed for the
+reading of the two circles of right ascension
+and of declination; a third serves for the reading
+of the position circle of the micrometer;
+two others are employed for the reading of the
+drums fixed upon the micrometric screws; four
+others serve for rendering the spider threads of
+the reticule brilliant upon a black ground; and
+still another serves for illuminating the field of
+the instrument where the same threads remain
+black upon a luminous ground. The currents
+that supply these lamps are brought over two
+different circuits, in which are interposed rheostats
+that permit of graduating the intensity
+of the light at will.</p>
+
+<p>Since the installation of the first model of an
+elbowed equatorial of 11 in. aperture, in 1882,
+at the Paris Observatory, the numerous and indisputable
+advantages of this sort of instrument
+have led a certain number of observatories
+to have similar, but larger, instruments
+constructed. In France, the observatories of
+Alger, Besancon, and Lyons have telescopes of
+this kind, the objectives of which have diameters
+of from 12 in. to 13 in., and which have
+been used for several years past in equatorial
+observations of all kinds. The Vienna Observatory
+has for the last two years been using an
+instrument of this kind whose objective has
+an aperture of 15 inches. Another equatorial
+of the same kind, of 16 in. aperture, is now in
+course of construction for the Nice Observatory,
+where it will be especially employed as a
+seeker of exceptional power&mdash;a role to which
+this kind of instrument lends itself admirably.
+The optical part of all these instruments was furnished
+by the Messrs. Henry, and the mechanical part by Mr.
+Gautier.</p>
+
+<p>The largest elbowed equatorial is, therefore, that of
+the Paris Observatory. Its optical power, moreover,
+corresponds perfectly to its huge dimensions. The experimental
+observations which have already been
+made with it fully justify the hopes that we had a
+right to found upon the professional skill of the eminent
+artists to whom we owe this colossal instrument.
+The images of the stars were given with the greatest
+sharpness, and it was possible to study the details of
+the surface of the moon and other planets, and several
+star clusters, in all their peculiarities, in the most remarkable
+manner.</p>
+
+<p>When it shall become possible to make use of this
+equatorial for celestial photography, there is no doubt
+that we shall obtain the most important results. As
+regards the moon, in particular, the photographing of
+which has already made so great progress, its direct
+image at the focus of the large 24 in. photographic objective
+will have a diameter of 11 in., and, being magnified,
+will be capable of giving images of more than
+3 ft. in diameter.&mdash;<i>La Nature</i>.</p>
+
+<hr />
+
+<a name="flo-1"></a><h2>LILY OF THE VALLEY.</h2>
+
+<p>There is no flower more truly and universally popular
+than the lily of the valley. What can be more delicious
+and refreshing than the scent of its fragrant
+flowers? What other plant can equal in spring the attractiveness
+of its pillars of pure white bells half hidden
+in their beautiful foliage? There are few gardens
+without a bed of lily of the valley, but too often the
+place chosen for it is some dark corner where nothing
+else would be expected to grow, but it is supposed as a
+matter of course that "it will do for a lily bed." The
+consequence is that although
+these lilies are very
+easy things to cultivate, as
+indeed they ought to be,
+seeing that they grow wild
+in the woods of this and
+other countries, yet one
+hears so often from those
+who take only a slight interest
+in practical gardening,
+"I have a lily bed,
+but I scarcely ever get any
+lilies." Wild lilies are hardly
+worth the trouble of gathering,
+they are so thin
+and poor; it is interesting
+to find a plant so beautiful
+and precious in the garden
+growing wild in the woods,
+but beyond that the flowers
+themselves are worth
+but very little. This at
+once tells us an evident
+fact about the lily of the
+valley, viz., that it does
+require cultivation. It is
+not a thing to be left alone
+in a dark and dreary corner
+to take care of itself
+anyhow year after year.
+People who treat it so deserve
+to be disappointed
+when in May they go to the
+lily bed and find plenty of
+leaves, but no flowers, or, if
+any, a few poor, weak attempts
+at producing blossoms,
+which ought to be
+so beautiful and fragrant.
+
+One great advantage of this lovely spring flower is that
+it can be so readily and easily forced. Gardeners in large
+places usually spend several pounds in the purchase of
+crowns and clumps of the lily of the valley, which
+they either import direct from foreign nurserymen or
+else procure from their own dealer in such things, who
+imports his lilies in large quantities from abroad. But
+we may well ask, Have foreign gardeners found out
+some great secret in the cultivation of this plant? Or is
+their climate more suitable for it? Or their soil adapted
+to growing it and getting it into splendid condition for
+forcing? It is impossible that the conditions for growing
+large and fine heads of this lily can be in any way
+better in Berlin or elsewhere than they are in our own
+land, unless greater heat in summer than we experience
+in England is necessary for ripening the growths
+in autumn.</p>
+
+<p>There is another question certainly as to varieties;
+one variety may be superior to another, but surely if
+so it is only on the principle of the survival of the fittest,
+that is to say, by carefully working on the finest
+forms only and propagating from them, a strong and
+vigorous stock may be the result, and this stock may
+be dignified with a special name. For my own part
+what I want is to have a great abundance of lily of the
+valley from February till the out-door season is over.
+To do this with imported clumps would, of course, be
+most costly, and far beyond what any person ought
+to spend on mere flowers. Though it must be remembered
+that it is an immense advantage to the parish
+priest to be able to take bright and sweet flowers to the
+bedside of the sick, or to gratify the weary spirit of a
+confirmed invalid, confined through all the lovely
+spring time to the narrow limits of a dull room, with
+the fragrant flowers of the lily of the valley. I determined,
+therefore, that I would have an abundance of
+early lilies, and that they should not be costly, but
+simply produced at about the same expense as any
+other flowers, and I have been very successful in accomplishing
+this by very simple means. First of all, it
+is necessary to have the means of forcing, that is to say
+the required heat, which in my case is obtained from
+an early vinery. I have seen lilies forced by pushing
+the clumps in under the material for making a hot bed
+for early cucumbers, the clumps being drawn out, of
+course, as soon as the flowers had made a good start.
+They have then to be carefully and very gradually exposed
+to full light, but often, although fine heads of
+bloom may be produced in this way, the leaves will be
+few and poor.</p>
+
+<p>My method is simply this: In the kitchen garden
+there is the old original bed of lilies of the valley in a
+corner certainly, but not a dark corner. This is the
+reservoir, as were, from whence the regular supply
+of heads for special cultivation is taken. This large
+bed is not neglected and left alone to take care of itself,
+but carefully manured with leaf mould and peat
+moss manure from the stable every year. Especially
+the vacant places made by taking out the heads for
+cultivation are thus filled up.</p>
+
+<p>Then under the east wall another piece of ground is
+laid out and divided into four plots. When I first began
+to prepare for forcing I waited four years, and
+had one plot planted with divided heads each year.
+Clumps are taken up from the reserve bed and then
+shaken out and the heads separated, each with its little
+bunch of fibrous roots. They are then carefully planted
+in one of the plots about 4 in. or 5 in. apart, the ground
+having previously been made as light and rich as possible
+with plenty of leaf mould. I think the best time
+for doing this is in autumn, after the leaves have
+turned yellow and have rotted away; but frequently
+the operation has been delayed till spring, without
+much difference in the result.</p>
+
+<p>Asparagus is usually transplanted in spring, and
+there is a wonderful affinity between the two plants,
+which, of course, belong to the same order. It was a
+long time to wait&mdash;four years&mdash;but I felt there was no
+use in being in too great a hurry, and every year the
+plants manifestly improved, and the buds swelled up
+nicely and looked more plump each winter when the
+leaves were gone. It must be remembered also that a
+nice crop of flowers could be gathered each year.
+When the fourth year came, the first plot was divided
+up into squares about 2 ft. each way, and taken up before
+any hard frost or snow had made their appearance,
+and put away on the floor of an unused stable.
+From the stable they are removed as required in the
+squares to the vinery, where they grow beautifully,
+not sending up merely fine heads of bloom without a
+vestige of leaf, but growing as they would in spring out
+of doors with a mass of foliage, among which one has
+to search for the spikes of flower, so precious for all
+sorts of purposes at that early season of the year.</p>
+
+<p>The spikes produced in this way do not equal in
+thickness and substance of petal the flowers which
+come from more carefully prepared clumps imported
+from Berlin, but they are fine and strong, and above
+all most abundant. I can not only supply the house
+and small vases for the church, but also send away
+boxes of the flowers to friends at a distance, besides the
+many gifts which can be made to those who are ill or
+invalids. Few gifts at such a time are more acceptable
+than a fragrant nosegay of lily of the valley. In order
+to keep the supply of prepared roots ready year after
+year, a plot of ground has only to be planted each
+autumn, so that in the rotation of years it may be
+ready for forcing when its turn shall come.</p>
+
+<p>As the season advances, as every one knows who has
+attempted to force the lily of the valley, much less
+time is taken in bringing the flowers to perfection under
+precisely the same circumstances as those in which
+the first sods are forced. In February or earlier the
+buds are more unwilling to start; there seems to be
+a natural repugnance against being so soon forced
+out of the winter's sleep and rest. But when the flowers
+do come, they are nearly as fine and their leaves are
+quite as abundant in this way of forcing as from the
+pieces introduced much later into heat. It would
+be easy to preserve the squares after all the flowers are
+gathered, but I found that they would not, like strawberries,
+kindly furnish forth another crop later on in
+the year, and, therefore, mine are flung away; and I
+have often pitied the tender leaves in the frost and
+snow after their short sojourn in the hot climate of the
+vinery. But the reserve bed will always supply an
+ample quantity of fresh heads, and it is best to take
+the new plants for preparation in the kitchen garden
+from this reserve bed.</p>
+
+<p>This very simple method of forcing lilies of the
+
+valley is within the reach of any one who has even a
+small garden and a warm house, and these two things
+are becoming more and more common among us
+every day.&mdash;<i>A Gloucestershire Parson, in The Garden</i>.</p>
+
+<hr />
+
+[Continued from SUPPLEMENT, No. 802, page 12820.]
+
+<a name="ent-1"></a><h2>REPORT ON INSECTS</h2>.
+
+<h3>THE ONION MAGGOT.</h3>
+
+<h4><i>Phorbia ceparum</i> (Meig.)</h4>
+
+
+<p>
+Early in June a somewhat hairy fly, Fig. 9, may be
+seen flying about, and depositing its eggs on the leaves
+of the young onion plants, near the roots, Fig. 10.</p>
+
+
+<img src="images/2-fig9.png" align="left" alt="FIG. 9." title="">
+
+<img src="images/2-fig10.png" align="right" alt="FIG. 10." title="">
+<br clear="all" />
+
+<p>Dr. Fitch describes this fly as follows: "It has a considerable
+resemblance to the common house fly, though
+when the two are placed side by side, this is observed
+as being more slender in its form. The two sexes are
+readily distinguished from each other by the eyes,
+which in the males are close together, and so large as
+to occupy almost the whole surface of the head, while
+in the females they are widely separated from each
+other. These flies are of an ash gray color, with the
+head silvery, and a rusty black stripe between the eyes,
+forked at its hind end. And this species is particularly
+distinguished by having a row of black spots along
+the middle of the abdomen or hind body, which sometimes
+run into each other, and then forming a continuous
+stripe.</p>
+
+<p>"This row of spots is quite distinct in the male, but
+in the female is very faint, or is often wholly imperceptible.
+This fly measured 0.22 to 0.25 inch in length,
+the females being usually rather larger than the males."
+The eggs are white, smooth, somewhat oval in outline,
+and about one twenty-fifth of an inch in length. Usually
+not more than half a dozen are laid on a single
+plant, and the young maggot burrows downward within
+the sheath, leaving a streak of pale green to indicate
+its path, and making its way into the root, devours all
+except the outer skin.</p>
+
+<p>The maggots reach their full growth in about two
+weeks, when they are about one-third of an inch long,
+white and glossy, tapering from the posterior end to
+the head, which is armed with a pair of black, hook-like
+jaws. The opposite end is cut off obliquely and has
+eight tooth-like projections around the edge, and a
+pair of small brown tubercles near the middle. Fig.
+11 shows the eggs, larva, and pupa, natural size and
+enlarged.</p>
+
+<img src="images/2-fig11.png" align="right" alt="FIG. 11." title="">
+
+<p>They usually leave the onions and transform to pupæ
+within the ground. The form of the pupa does not
+differ very much from the maggot, but the skin has
+hardened and changed to a chestnut brown color, and
+they remain in this stage about two weeks in the summer,
+when the perfect flies emerge. There are successive
+broods during the season, and the winter is passed
+in the pupa stage.</p>
+
+<p>The following remedies have been suggested:</p>
+
+<p>Scattering dry, unleached wood ashes over the plants
+as soon as they are up, while they are wet with dew,
+and continuing this as often as once a week through
+the month of June, is said to prevent the deposit of
+eggs on the plants.</p>
+
+<p>Planting the onions in a new place as remote as possible
+from where they were grown the previous year
+has been found useful, as the flies are not supposed to
+migrate very far.</p>
+
+<p>Pulverized gas lime scattered along between the rows
+has been useful in keeping the flies away.</p>
+
+<p>Watering with liquid from pig pens collected in a
+tank provided for the purpose, was found by Miss Ormerod
+to be a better preventive than the gas lime.</p>
+
+<p>When the onions have been attacked and show it by
+wilting and changing color, they should either be taken
+up with a trowel and burned, or else a little diluted
+carbolic acid, or kerosene oil, should be dropped on
+the infested plants to run down them and destroy the
+maggots in the roots and in the soil around them.</p>
+
+<p>Instead of sowing onion seed in rows, they should
+be grown in hills, so that the maggots, which are footless,
+cannot make their way from one hill to another.</p>
+
+
+<h3>THE CABBAGE BUTTERFLY.</h3>
+
+<h4><i>Pieris rapae</i> (Linn.)</h4>
+
+<p>In the New England States there are three broods
+of this insect in a year, according to Mr. Scudder, the
+butterflies being on the wing in May, July, and September;
+but as the time of the emergence varies, we
+see them on the wing continuously through the
+season.</p>
+
+<img src="images/2-fig12.png" align="right" alt="FIG. 12." title="">
+
+<p>The expanded wings, Fig. 12, male, measure about
+two inches, are white above, with the base dusky. Both
+sexes have the apex black and a black spot a little beyond
+the middle, and the female, Fig. 13, has another
+spot below this. The under side of the fore wings is
+white, yellowish toward the apex, and with two black
+spots in both sexes corresponding to those on the upper
+side of the female. A little beyond the middle of the
+costa, on the hind wings, is an irregular black spot on
+the upper surface, while the under surface is pale
+lemon yellow without marks, but sprinkled more or
+less with dark atoms. The body is black above and
+white beneath.</p>
+
+<img src="images/2-fig13.png" align="left" alt="FIG. 13." title="">
+
+<p>The caterpillars of this insect feed on the leaves of
+cabbage, cauliflower, turnip, mignonette, and some
+other plants.</p>
+
+<p>The female lays her eggs on the under side of the
+leaves of the food plants, generally, but sometimes on
+the upper sides or even on the leaf stalks. They are
+sugar loaf shaped, flattened at the base, and with the
+apex cut off square at the top, pale lemon yellow in
+color, about one twenty-fifth of an inch long and one
+fourth as wide, and have twelve longitudinal ribs with
+fine cross lines between them.</p>
+
+<p>The eggs hatch in about a week, and the young caterpillars,
+which are very pale yellow, first eat the shells
+from which they have escaped, and then spin a carpet
+of silk, upon which they remain except when feeding.
+They now eat small round holes through the leaves,
+but as they grow older change to a greenish color, with
+a pale yellow line along the back, and a row of small
+yellow spots along the sides, and eat their way down
+into the head of the cabbage.</p>
+
+<img src="images/2-fig14.png" align="right" alt="FIG. 14." title="">
+
+<p>Having reached its full growth, the caterpillar, Fig.
+14, a, which is about an inch in length, wanders off to
+some sheltered place, as under a board, fence rail, or
+even under the edge of clapboards on the side of a
+building, where it spins a button of silk, in which to
+secure its hind legs, then the loop of silk to support
+the forward part of the body.</p>
+
+<p>It now casts its skin, changing to a chrysalis, Fig. 14,
+b, about three-fourths of an inch in length, quite
+rough and uneven, with projecting ridges and angular
+points on the back, and the head is prolonged into a
+tapering horn. In color they are very variable, some
+are pale green, others are flesh colored or pale ashy
+gray, and sprinkled with numerous black dots. The
+winter is passed in the chrysalis stage.</p>
+
+<p>After the caterpillar changes to a chrysalis, their
+minute parasites frequently bore through the outside
+and deposit their eggs within. These hatch before the
+time for the butterflies to emerge, and feeding on the
+contents, destroy the life of the chrysalis.</p>
+
+<p>Birds and spiders are of great service in destroying
+these insects.</p>
+
+<p>The pupæ should be collected and burned if the
+abdomen is flexible; but if the joints of the abdomen
+are stiff and cannot be easily moved, they should be
+left, as they contain parasites.</p>
+
+<p>Several applications of poisons have been used, the
+best results being obtained from the use of pyrethrum
+as a powder blown on to the plants by a hand bellows,
+during the hottest part of the day, in the proportion
+of one part to four or five of flour.</p>
+
+<p>As the eggs are laid at different times, any application,
+to be thoroughly tested, must be repeated several
+times.</p>
+
+
+<h3>THE APPLE TREE TENT CATERPILLAR.</h3>
+
+<h4><i>Clisiocampa Americana</i> (Harr.)</h4>
+
+<p>Large, white, silken web-like tents, Fig. 15, are
+noticed by the roadsides, in the early summer, on wild
+
+cherry trees, and also on fruit trees in orchards, containing
+numerous caterpillars of a blackish color, with
+fine gray hairs scattered over the body.</p>
+
+<p>This well known pest has been very abundant
+throughout the State for several years past, and the
+trees in many neglected orchards have been greatly
+injured by it, some being entirely stripped of their
+leaves. The trees in these orchards and the neglected
+ones by the roadsides form excellent breeding places for
+this insect, and such as are of little of no value should
+be destroyed. If this were well done, and all fruit
+growers in any given region were to destroy all the
+tents on their trees, even for a single season, the work
+of holding them in check or destroying them in the
+following year would be comparatively light.</p>
+
+<img src="images/3-fig15.png" align="left"  alt="FIG. 15." title="">
+
+<p>The moths, Fig. 16, appear in great numbers in July,
+their wings measuring, when expanded, from one and a
+quarter to one and a half inches or more. They are of a
+reddish brown color, the fore wings being tinged with
+gray on the base and middle, and crossed by two
+oblique whitish stripes.</p>
+
+<img src="images/3-fig16.png" align="left" alt="FIG. 16." title="">
+
+<p>The females lay their eggs, about three hundred in
+number, in a belt, Fig. 15, c, around the twigs of apple,
+cherry, and a few other trees, the belt being covered
+by a thick coating of glutinous matter, which probably
+serves as a protection against the cold weather during
+winter.</p>
+
+<p>The following spring, when the buds begin to swell,
+the egg hatch and the young caterpillar seek some fork
+of a branch, where they rest side by side. They are
+about one-tenth of an inch long, of a blackish color,
+with numerous fine gray hairs on the body. They feed
+on the young and tender leaves, eating on an average
+two apiece each day. Therefore the young of one pair
+of moths would consume from ten to twelve thousand
+leaves; and it is not uncommon to see from six to eight
+nests or tents on a single tree, from which no less than
+seventy-five thousand leaves would be destroyed&mdash;a
+drain no tree can long endure.</p>
+
+<p>As the caterpillars grow, a new and much larger
+skin is formed underneath the old one, which splits
+along the back and is cast off. When fully grown, Fig.
+15, a and b, which is in about thirty-five to forty days
+after emerging from the eggs, they are about two
+inches long, with a black head and body, with numerous
+yellowish hairs on the surface, with a white stripe
+along the middle of the back, and minute whitish or
+yellowish streaks, which are broken and irregular along
+the sides; and there is also a row of transverse, small,
+pale blue spots along each side of the back.</p>
+
+<p>As they move about they form a continuous thread
+of silk from a fleshy tube on the lower side of the
+mouth, which is connected with the silk-producing
+glands in the interior of the body, and by means of this
+thread they appear to find their way back from the
+feeding grounds. It is also by the combined efforts of
+all the young from one belt of eggs that the tents are
+formed.</p>
+
+<p>These caterpillars do not feed during damp, cold
+weather, but take two meals a day when it is pleasant.</p>
+
+<p>After reaching their full growth, they leave their
+tents and scatter in all directions, seeking for some
+protected place where each one spins its spindle-shaped
+cocoon of whitish silk intermingled with sulphur colored
+powder, Fig. 15, d. They remain in these cocoons,
+where they have changed to pupæ, from twenty to
+twenty-five days, after which the moths emerge, pair,
+and the females lay their eggs for another brood.</p>
+
+<p>Several remedies have been suggested, a few of which
+are given below. Search the trees carefully, when
+they are bare, for clusters of eggs; and, when found,
+cut off the twigs to which they are attached, and burn
+them.</p>
+
+<p>As soon as any tents are observed in the orchard
+they should be destroyed, which may be readily and
+effectually done by climbing the trees, and with the
+hand protected by a mitten or glove, seize the tent and
+crush it with its entire contents; also swab them down
+with strong soapsuds or other substances; or tear
+them down with a rounded bottle brush.</p>
+
+<p>Burning with a torch not only destroys the caterpillars
+but injures the trees.</p>
+
+<p>It should be observed, however, since the caterpillars,
+are quite regular in taking their meals, in the
+middle of the forenoon and afternoon, that they
+
+should be destroyed only in the morning or evening,
+when all are in the tent.</p>
+
+<p>Another remedy is to shower the trees with Paris
+green in water, in the proportion of one pound to one
+hundred and fifty gallons of water.</p>
+
+<h3>THE FOREST TENT CATERPILLAR.</h3>
+
+<h4><i>Clisiocampa disstria</i> (Hübner.)</h4>
+
+<img src="images/3-fig17.png" align="right" alt="FIG. 17." title="">
+
+<p>This species, commonly known as the forest tent
+caterpillar, closely resembles the apple tree tent caterpillar,
+but does not construct a visible tent. It feeds
+on various species of forest trees, such as oak, ash,
+walnut, hickory, etc., besides being very injurious to
+apple and other fruit trees. The moth, Fig. 17, b, expands
+an inch and a half or more. The general color
+is brownish yellow, and on the fore wings are two
+oblique brown lines, the space between them being
+darker than the rest of the wing. The eggs, Fig. 17,
+c and d, which are about one twenty fifth of an inch
+long and one fortieth wide, are arranged, three or four
+hundred in a cluster, around the twigs of the trees,
+Fig. 17, a. These clusters are uniform in diameter and
+cut off squarely at the ends. The eggs are white, and
+are firmly fastened to the twigs and to each other, by
+a brown substance, like varnish, which dries, leaving
+the eggs with a brownish covering.</p>
+
+
+<p>The eggs hatch about the time the buds burst, or before,
+and the young caterpillars go for some time
+without food, but they are hardy and have been
+known to live three weeks with nothing to eat, although
+the weather was very cold.</p>
+
+<img src="images/3-fig18.png" align="left" alt="FIG. 18." title="">
+
+<p>As soon as hatched they spin a silken thread wherever
+they go, and when older wander about in search
+for food. The caterpillars are about one and a half
+inches long when fully grown, Fig. 18. The general
+color is pale blue, tinged with greenish low down on
+the sides, and everywhere sprinkled with black dots or
+points, while along the middle of the back is a row of
+white spots each side of which is an orange yellow
+stripe, and a pale, cream yellow stripe below that.
+These stripes and spots are margined with black. Each
+segment has two elevated black points on the back,
+from each of which arise four or more coarse black
+hairs. The back is clothed with whitish hairs, the head
+is dark bluish freckled with black dots, and clothed
+with black and fox-colored hairs, and the legs are
+black, clothed with whitish hairs.</p>
+
+<p>At this stage the caterpillars may be seen wandering
+about on fences, trees, and along the roads in search of
+a suitable place to spin their cocoons, which are
+creamy white, and look very much like those of the
+common tent caterpillar, except that they are more
+loosely constructed.</p>
+
+<p>Within the cocoons, in two or three days they transform
+to pupæ of a reddish brown color, densely clothed
+with short pale yellowish hairs. The moths appear in
+two or three weeks, soon lay their eggs and then die.
+The insects are not abundant many years in succession,
+as their enemies, the parasites, increase and check
+them.</p>
+
+<p>Many methods have been suggested for their destruction,
+but the most available and economical are to remove
+the clusters of eggs whenever found, and burn
+them, and to shower the trees with Paris green in the
+proportion of one pound to one hundred and fifty gallons
+of water.</p>
+
+<h3>THE STALK BORER.</h3>
+
+<h4><i>Gortyna nitela</i> (Gruen.)</h4>
+
+<p>The perfect moth, Fig. 19, 1, expands from one to
+one and a half inches. The fore wings are a mouse
+gray color, tinged with lilac and sprinkled with fine
+yellow dots, and distinguished mainly by a white band
+extending across the outer part. The moths hibernate
+in the perfect state, and in April or May deposit
+their eggs singly on the outside of the plant upon
+which the young are to feed. As soon as the eggs
+hatch, which is in about a month, the young larvæ, or
+caterpillars, gnaw their way from the outside into
+the pith.</p>
+
+<img src="images/3-fig19.png" align="right" alt="FIG. 19." title="">
+
+<p>The plant does not show any sign of decay until the
+caterpillar is fully grown, when it dies. The caterpillar,
+Fig. 19, 2, is about one and one-fourth inches long,
+of a reddish brown color, with whitish stripes along the
+body. The stripes on the sides are not continuous,
+and the shading of the body varies, being darker on
+the anterior than on the posterior portion. When
+fully grown, Fig. 20, the color is lighter and the stripes
+are broader. At this stage of life it burrows into the
+
+ground just beneath the surface, and changes into the
+pupa state. The pupa is three-fourths of an inch long,
+and of a mahogany brown color. The perfect moth
+appears about the first of September, and there is only
+one brood in a season.</p>
+
+<img src="images/3-fig20.png" align="right" alt="FIG. 20." title="">
+
+<p>The caterpillars feed in the stalks of corn, tomatoes,
+potatoes, dahlias, asters, and also in young currant
+bushes, besides feeding on many species of weeds. By
+a close inspection of the plants about the beginning of
+July, the spot where the borer entered, which is generally
+quite a distance from the ground, may be detected,
+and the caterpillar cut out without injury to the
+plant. This plan is impracticable for an extensive
+crop, but by destroying the borers found in the vines
+that wilt suddenly, one can lessen the number another
+year.</p>
+
+<h3>THE PYRAMIDAL GRAPEVINE CATERPILLAR.</h3>
+
+<h4><i>Pyrophila pyramidoides</i> (Guen.)</h4>
+
+<p>This caterpillar, Fig. 21, is generally found on grapevines
+early in June, but also feeds on apple, plum,
+raspberry, maple, poplar, etc. It is about an inch and
+a half in length, with the body tapering toward the
+head; of a whitish green color, darker on the sides;
+with a longitudinal white stripe on the back, broader
+on the last segments. Low down on each side is a
+bright yellow stripe, between this and the one on the
+back is another less distinct, and the under surface of
+the body is pale green.</p>
+
+<img src="images/3-fig21.png" align="left" alt="FIG. 21." title="">
+
+<p>The caterpillar is fully grown about the middle or
+last of June, when it descends to the ground, draws
+together some of the fallen leaves, and makes a
+cocoon, in which it soon changes to a mahogany brown
+pupa.</p>
+
+<img src="images/3-fig22.png" align="right" alt="FIG. 22." title="">
+
+<p>In the latter part of July the perfect moth, Fig. 22,
+emerges, measuring, when its wings are expanded,
+about one and three-fourths inches; the fore wings are
+dark brown shaded with lighter, with dots and wavy
+lines of dull white. The hind wings are reddish, or of
+a bright copper color, shading to brown on the outer
+angle of the front edge of the wing, and paler toward
+the hinder and inner angle.</p>
+
+<p>The under surface of the wings is lighter than the
+upper, and the body is dark brown, with its posterior
+portion banded with lines of a paler hue.</p>
+
+<p>This pest may be destroyed by hand picking, or
+by jarring the trees or vines on which they are feeding,
+when they will fall to the ground and may be crushed
+or burned.</p>
+
+<h3>THE GRAPE BERRY MOTH.</h3>
+
+<h4><i>Eudemis botrana</i> (S.V.)</h4>
+
+<p>The moths emerge and fly early in June, and are
+quite small, measuring, when the wings are expanded,
+only two-fifths of an inch, Fig. 23, a, enlarged. The
+fore wings are purplish or slate brown from the base to
+the middle, the outer half being irregularly marked
+with dark and light brown.</p>
+
+<img src="images/3-fig23.png" align="left" alt="FIG. 23." title="">
+
+<p>These insects are two-brooded and the first brood
+feeds not only on the leaves of the grape, but on tulip,
+sassafras, vernonia and raspberry. The caterpillars of
+the second brood emerge when the grapes are nearly
+grown, and bore in them a winding channel to the
+pulp, continuing to eat the interior of the berry till
+the pulp is all consumed, Fig. 23, d, when, if not full
+grown, they draw one or two other berries close to the
+first and eat the inside of those.</p>
+
+<p>The mature caterpillar, Fig. 23, b, measures about
+half an inch in length, is dull greenish, with head and
+thoracic shield somewhat darker; the internal organs
+give the body a reddish tinge. It then leaves the grape
+and forms its cocoon by cutting out a piece of a leaf,
+leaving it hinged on one side; then rolling the cut end
+over, fastens it to the leaf, thus making for itself a
+cocoon in which to pupate. The pupa is dark reddish
+brown.</p>
+
+<p>The second generation passes the winter in the pupa
+state, attached to leaves which fall to the ground;
+therefore, if all the dead and dried leaves be gathered
+in the fall and burned, also all the decayed fruit, a
+great many of these insects would be destroyed. As
+
+the caterpillars feed inside of the berry, no spraying
+of the vines with poisons would reach them. The caterpillar
+makes a discolored spot where it enters the
+berry, Fig. 23, c. Therefore the infested fruit may be
+easily detected and destroyed.</p>
+
+<p>There is a small parasite that attacks this insect and
+helps to keep it in check. The insect has been known
+in Europe over a hundred years. It is not certain
+when it was introduced into America, but it is now
+found from Canada to the Gulf of Mexico, and from
+the Atlantic to the Pacific Ocean.</p>
+
+<h3>THE CODLING MOTH.</h3>
+
+<h4><i>Carpocapsa pomonella</i> (Linn.)</h4>
+
+<p>This well known insect has a world-wide reputation,
+and is now found wherever apples are raised.</p>
+
+<img src="images/4-fig24.png" align="right" alt="FIG. 24." title="">
+
+<p>The moths are on the wing about the time the young
+apples are beginning to set, and the female lays a
+single egg in the blossom end of each apple. The fore
+wings of the moths when expanded, Fig. 24, g (f, with
+the wings closed), measure about half an inch across,
+and are marked with alternate wavy, transverse streaks
+of ashy gray and brown, and have on the inner hind
+angle a large tawny brown, horseshoe shaped spot,
+streaked with light bronze or copper color. The hind
+wings and abdomen are light brown with a luster of
+satin.</p>
+
+<p>Each female lays about fifty eggs, which are minute,
+flattened, scale-like bodies of a yellowish color. In
+about a week the eggs hatch and the tiny caterpillar
+begins to eat through the apple to the core, Fig. 24, a,
+pushing its castings out through the hole where it
+entered, Fig. 24, b. Oftentimes these are in sight on
+the outside in a dark colored mass, thus making wormy
+apples plainly seen at quite a distance.</p>
+
+<p>The caterpillar is about two-fifths of an inch in
+length, of a glossy, pale yellowish white color, with a
+light brown head. The skin is transparent and the
+internal organs give to it a reddish tinge.</p>
+
+<p>When mature the caterpillars, Fig. 24, e, top of head
+and second segment, h, emerge from the apples and
+seek some sheltered place, such as crevices of bark, or
+corners of the boxes or barrels in which the fruit is
+stored, where they spin a tough whitish cocoon, Fig.
+24, i, in which they remain unchanged all winter, and
+transform to pupæ, Fig. 24, d, the next spring, the perfect
+moths emerging in time to lay their eggs in the
+new crop of apples.</p>
+
+<p>One good remedy is to gather all the fallen apples,
+and feed them to hogs; another is to let swine and
+sheep run in the orchard, and eat the infested fruit.</p>
+
+<p>It has been recommended to place bands of cloth or
+hay around the trunks of the trees for the caterpillars
+to spin their cocoons beneath, and to remove them at
+the proper time, and put them in scalding water to
+destroy the worms.</p>
+
+<p>By far the most successful method as yet adopted is
+to shower the apple trees with Paris green in water,
+one pound to one hundred and fifty gallons of water,
+when the apples are about the size of peas, and again
+in about a week.</p>
+
+
+<h3>THE CABBAGE LEAF MINER.</h3>
+
+<h4><i>Plutella cruciferarum</i> (Zell.)</h4>
+
+<p>The cabbage leaf miner is not a native of this country,
+but was imported from Europe.</p>
+
+<img src="images/4-fig25.png" align="left" alt="FIG. 25." title="">
+
+<p>The perfect moth, Fig. 25, f, with the wings expanded
+(h, with the wings closed, g, a dark variety), measures
+three-quarters of an inch. The fore wings are
+ashy gray, and on the hinder margin is a white or yellowish
+white stripe having three points extending into
+the gray, thus forming, when the wings are closed,
+three diamond-shaped white spots. Generally there is
+a dark brown stripe between the white and the gray.
+There are also black dots scattered about on the
+anterior part of these wings.</p>
+
+<p>The hind wings are leaden brown, and the under
+side of all the wings is leaden brown, glossy, and without
+any dots.</p>
+
+<p>The antennæ are whitish with dark rings, and the
+abdomen white. There are two broods of this insect in
+this region, the moths of the first appearing in May,
+and those of the second in August. They hibernate in
+the pupa stage.</p>
+
+<p>The caterpillars, Fig. 25, a (b, the top and c, the side
+of a segment), appear in June or July and September;
+they are small and cylindrical, tapering at both ends,
+pale green, and about one-fourth of an inch long. The
+head has a yellowish tinge, and there are several dark
+stiff hairs scattered over the body.</p>
+
+<p>When ready to transform, this caterpillar spins a
+delicate gauze-like cocoon, Fig. 25, e, made of white,
+silken threads, on the under side of a cabbage leaf.
+The pupa, Fig. 25, d, and i, the end of a pupa, is commonly
+white, sometimes shaded with reddish brown,
+and can be distinctly seen through the silken case.</p>
+
+<p>The first brood is more injurious than the second, as
+it feeds on the young cabbage leaves before the head is
+formed, and this must surely stunt the growth and
+make weak, sickly plants; while the second brood
+feeds only on the outside leaves. The caterpillars are
+very active, wriggling violently when disturbed, and
+falling by a white silken thread.</p>
+
+<p>Hot dry weather is favorable to them and enables
+them to multiply rapidly. Advantage has been taken
+of this fact, and spraying the plants thoroughly with
+water is strongly recommended. Prof. Riley states
+that the insects are very readily destroyed by pyrethrum.
+There are two species of spiders and a species
+of ichneumon fly that destroy them.</p>
+
+
+<h3>THE GARTERED PLUME MOTH.</h3>
+
+<h4><i>Oxyptilus periscelidactylus</i> (Fitch.)</h4>
+
+<p>The caterpillars of this species draw together the
+young grape leaves, Fig. 26, a, in the spring, with fine
+silken threads, and feed on the inside, thus doing much
+damage in proportion to their size. These caterpillars,
+Fig. 26, a, and e, a segment greatly enlarged, are full
+grown in about two weeks, when they are about one-fourth
+of an inch long, pale green with whitish hairs
+arising from a transverse row of warts on each segment.</p>
+
+<p>Early in June they transform to pupæ, Fig. 26, b,
+which are pale green at first and change to dark brown.
+The surface is rough and the head is cut off obliquely,
+while on the upper side near the middle are two sharp
+pointed horns, Fig. 26, c. They remain in this stage
+from a week to ten days, when the moths emerge.</p>
+
+<p class="ctr">
+<img src="images/4-fig26.png" alt="FIG. 26." title="">
+</p>
+
+<p>The moths, Fig. 26, d, belong to the family commonly
+known as plume moths or feather wings
+(Pterophoridæ), from having their wings divided into
+feather-like lobes. When the wings are expanded they
+measure about seven-tenths of an inch across. They
+are yellowish brown with a metallic luster, and have
+several dull whitish streaks and spots. The fore wings
+are split down the middle about half way to their base,
+the posterior half having a notch in the outer margin.
+The body is somewhat darker than the wings.</p>
+
+<p>It is not known positively in what stage the winter
+is passed, but it is supposed to be the perfect, or imago
+stage. The unnatural grouping and spinning of the
+leaves together leads to their detection, and they can
+be easily destroyed by hand picking and then crushing
+or burning them.</p>
+
+<hr />
+
+<a name="misc-1"></a><h2>THE BREEDS OF DOGS.</h2>
+
+<p>The dog exhibitions that have annually taken place
+for the last eight years at Paris and in the principal
+cities of France have shown how numerous and varied
+the breeds of dogs now are. It is estimated that there
+are at present, in Europe, about a hundred very distinct
+and very fine breeds (that is to say, such as reproduce
+their kind with constant characters), without
+counting a host of sub-breeds or varieties that a number
+of breeders are trying to fix.</p>
+
+<p>Most of the breeds of dogs, especially those of modern
+creation, are the work of man, and have been obtained
+by intercrossing older breeds and discarding all
+the animals that departed from the type sought. But
+many of these breeds are also the result of accident, or
+rather of modifications of certain parts of the organism&mdash;of
+a sort of rachitic or teratological degeneration
+which has become hereditary and has been due to
+domestication; for it is proved that the dog is the
+most anciently domesticated animal, and that its submission
+to man dates back to more than five thousand
+years. Such is the origin of the breeds of terriers, bulldogs,
+and all of the small house dogs.</p>
+
+<p>Man has often, designedly or undesignedly, aided in
+the production of breeds of this last category by submitting
+the dog to a regimen contrary to nature, or
+setting to work to reproduce an animal born monstrous,
+either for curiosity or for interest. As well known,
+the accidental characters and the spontaneous modifications
+which work no injury to the essential functions
+of life became easily hereditary, and the same is the
+case with certain artificial modifications pursued for a
+long series of generations.</p>
+
+<p>It was the opinion of Buffon that the breeds of dogs,
+which were already numerous in his time, were all derived
+from a single type, which, according to him, was
+the shepherd's dog. Other scientists have insisted that
+the dog descended from the wolf, and others from the
+jackal. At the present time, it is rightly admitted that
+several species of wild dogs have concurred in the formation
+of the different breeds of dogs as we now have
+them.</p>
+
+<p>In the lacustrine habitations of the stone age in
+Sweden, and in the <i>kjoekkenmoedding</i> (kitchen remains)
+of Denmark, of the same epoch, we find the remains
+of a dog, which, according to Rutymeyer, belongs
+to a breed which is constant up to its least details,
+and which is of a light and elegant conformation,
+of medium size, with a spacious and rounded cranium
+and a short, blunt muzzle, and a medium sized jaw,
+the teeth of which form a regular series.</p>
+
+<p>This dog, which has been named by geologists <i>Canis
+palustris</i>, fully resembles in size, slenderness of the
+limbs, and weakness of the muscular insertions, the
+spaniel, the brach hound, or the griffon.</p>
+
+<p>This dog of the stone age is entirely distinct from the
+wolf and jackal, of which some regard the domestic
+dog as a descendant, and as it has appeared in Denmark
+as well as in Sweden, there is no doubt that this
+species, peculiar to Europe, was subjugated by man
+and used by him, in the first place, for hunting, and
+later on for guarding houses and cattle. Later still,
+in the age of metals, we observe the appearance,
+both in Denmark and Sweden, of larger and stronger
+breeds of dogs, having in their jaws the character of
+mastiffs, and probably introduced by the first emigrants
+from Asia.</p>
+
+<p>There are, moreover, historic proofs that the dogs of
+the strongest breeds are indigenous to Asia, where we
+still find the dog of Thibet, the most colossal of all; in
+fact, in Pliny we read the following narrative: Alexander
+the Great received from a king of Asia a dog of
+huge size. He wished to pit it against bears and wild
+boars, but the dog remained undisturbed and did not
+even rise, and Alexander had it killed. On hearing of
+
+this, the royal donor sent a second dog like the first,
+along with word that these dogs did not fight so weak
+animals, but rather the lion and the elephant, and
+that he had only two of such individuals, and in
+case that Alexander had this one killed, too, he would
+no longer find his equal. Alexander matched this dog
+with a lion and then with an elephant, and he killed
+them both. Alexander was so afflicted at the premature
+death of the first dog, that he built a city and
+temples in honor of the animal.</p>
+
+<p>Did the mountainous province of Epirus called
+Molossia, in ancient Greece, give its name to the
+<i>molossi</i> that it produced, or did these large dogs give
+their name to the country? At all events, we know
+that it was from Epirus that the Romans obtained the
+molossi which fought wild animals in the circuses, and
+that from Rome they were introduced into the British
+islands and have became the present mastiffs.</p>
+
+<p>Although our hunting and shepherd's dogs have a
+European and the mastiffs an Asiatic ancestry, the
+ancestry of the harriers is African, and especially
+Egyptian; in fact, in Upper Egypt we find a sort of large
+white jackal (<i>Simenia simensis</i>) with the form of a
+harrier, and which Paul Gervais regarded with some
+reason as the progenitor of the domestic harrier, and a
+comparison of their skulls lends support to this opinion.</p>
+
+<p>A study of the most ancient monuments of the
+Pharaohs shows that the ancient Egyptians already
+had at least five breeds of dogs: two very slim watch
+dogs, much resembling the harrier, a genuine harrier,
+a species of brach hound and a sort of terrier with
+short and straight legs. All these dogs had erect ears,
+except the brach, in which these organs were pendent,
+and this proves that the animal had already undergone
+the effects of domestication to a greater degree
+than the others. The harrier of the time of the
+Pharaohs still exists in great numbers in Kordofan, according
+to Brehm.</p>
+
+<p>Upon the whole, we here have, then, at least three
+stocks of very distinct dogs: 1, a hunting or shepherd's
+dog, of European origin; 2, a mastiff, typical of the
+large breed of dogs indigenous to Asia; and 3, a harrier,
+indigenous to Africa.</p>
+
+<p>We shall not follow the effects of the combination of
+these three types through the ages, and the formation
+of the different breeds; for that we shall refer our
+readers to a complete work upon which we have been
+laboring for some years, and two parts of which have
+already appeared.<a name="FNanchor_1"></a><a href="#Footnote_1"><sup>1</sup></a></p>
+
+<p>We shall rapidly pass in review the different breeds
+of dogs that one may chance to meet with in our dog
+shows, beginning with the largest. It is again in mountainous
+countries that the largest dogs are raised, and
+the character common to all of these is a very thick
+coat. The largest of all, according to travelers, is the
+Thibetan dog. Buffon tells of having seen one which,
+when seated, was five feet in height. One brought
+back by the Prince of Wales from his voyage to the
+Indies was taller in stature, stronger and more stocky
+than a large mastiff, from which it differed, moreover,
+in its long and somewhat coarse hair, which was
+black on the back and russet beneath, the thighs and
+the tail being clothed with very long and silky hair.</p>
+
+<p>In France, we have a beautiful mountain dog&mdash;the
+dog of the Pyrenees&mdash;which is from 32 to 34 inches in
+height at the shoulders, and has a very thick white
+coat, spotted above with pale yellow or grayish fox
+color. It is very powerful, and is capable of successfully
+defending property or flocks against bears and
+wolves.</p>
+
+<p>The Alpine dog is the type of the mountain dog. It
+is of the same size as the dog of the Pyrenees, and differs
+therefrom especially in its coloring. It is white
+beneath, with a wide patch of orange red covering
+the back and rump. The head and ears are of the
+same color, with the addition of black on the edges;
+but the muzzle is white, and a stripe of the same color
+advances upon the forehead nearly up to the nape of
+the neck. The neck also is entirely white. There are
+two varieties of the Alpine or St. Bernard dog, one
+having long hair and the other shorter and very thick
+hair. We give in Fig. 1 a portrait of Cano, a large
+St. Bernard belonging to Mr. Gaston Leonnard.</p>
+
+<p class="ctr"><a href="./images/4-fig1.png">
+<img src="images/4-fig1-th.jpg" alt="FIG.1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD." title="">
+</a><br clear="all" />FIG.1&mdash;LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.</p>
+
+<p>Although this breed originated at the celebrated
+convent of St. Bernard, it no longer exists there in a
+state of purity, and in order to find fine types of it we
+have to go to special breeders of Switzerland and England.
+The famous Plinnlimon, which was bought for
+$5,000 by an American two or three years ago, and
+about which there was much talk in the papers, even
+the political ones, was born and reared in England.
+It appears that it is necessary, too, to reduce the number
+of life-saving acts that it is said are daily performed
+by the St. Bernard dogs. This is no longer but a
+legend. There was, it is true, a St. Bernard named
+Barry, now exhibited in a stuffed state in the Berne
+Museum, which accomplished wonders in the way of
+saving life, but this was an exception, and the reputation
+of this animal has extended to all others of its
+kind. These latter are simply watch dogs kept by the
+monks for their own safety, and which do not go at all
+by themselves alone to search for travelers that have
+lost their way in the snow.</p>
+
+<p>The Newfoundland dog, which differs from the preceding
+in its wholly black or black and white coat,
+was, it appears, also of mountain origin. According
+to certain authors, it is indigenous to Norway, and was
+carried to Newfoundland by the Norwegian explorers
+who discovered the island. Adapted to their new existence,
+they have become excellent water dogs, good
+swimmers, and better life savers by far than the majority
+of their congeners.</p>
+
+<p>Is it from descending to the plain that the mountain
+dogs have lost their long hair and have become short
+haired dogs like the English dog or mastiff and the
+German or large Danish dogs? It is very probable.
+At all events, it is by this character of having short
+hair that mastiffs are distinguished from the mountain
+dogs. Again, the large breed of dogs are distinguished
+from each other by the following characters: The mastiff
+is not very high at the shoulders (30 inches), but he
+is very heavy and thick set, with powerful limbs, large
+head, short and wide muzzle and of a yellowish or café-au-lait
+color accompanying a black face; that is to say,
+the ears, the circumference of the eyes and the muzzle
+are of a very dark color. The German or large Danish
+dogs constitute but one breed, but of three varieties,
+according to the coat: (1) those whose coat is of a
+uniform color, say a slaty gray or isobelline of varying
+depth, without any white spots; (2) those having a
+fawn colored coat striped transversely with black like
+the zebra, but much less distinctly; (3) those having a
+spotted coat, that is to say, a coat with a white ground
+strewed with irregular black spots of varying size.
+These, like those of the first variety are generally small-eyed.
+Whatever be the variety to which they belong,
+the German or large Danish dogs are slimmer than,
+and not so heavy as, the mastiffs. Some, even, are so
+light that it might be supposed that they had some
+heavier blood in their veins. They have also a longer
+muzzle, although square, and are quicker in gait and
+motions.</p>
+
+<p>The largest dogs are to be met with in this breed, and
+the beautiful Danish dog belonging to Prof. Charcot
+(Fig. 2) is certainly the largest dog in France and perhaps
+in Europe. It measures 36 inches at the shoulders
+and has an osseous and muscular development
+perfectly in keeping with its large stature, and at the
+same time has admirable proportions and lightness,
+and its motions are comparable to those of the finest
+horse.</p>
+
+<p class="ctr"><a href="./images/4-fig2.png">
+<img src="images/4-fig2-th.jpg" alt="FIG. 2" title="">
+</a><br clear="all" />FIG. 2&mdash;DR. CHARCOT'S LARGE DANISH DOG.</p>
+
+<p>Among the English dogs or mastiffs, we very frequently
+meet with individuals in which the upper incisors
+and canines are placed back of the corresponding
+ones in the lower jaw, this being due to a slight shortening
+of the bones of the upper jaw, not visible externally.
+This is the first degree of an artist of teratological
+development, which, since the middle ages,
+has become very marked in certain subjects, and has
+given rise to a variety in which this defect has become
+hereditary. Such is the origin of the breed of bulldogs.
+The latter were originally as large as the mastiffs.
+Carried to Spain under Philip II., they have
+there preserved their primitive characters, but the bulldogs
+remaining in England have continued to degenerate,
+so that now the largest are scarcely half the
+size of the Spanish bulldog, and the small ones attain
+hardly the size of the pug, although they preserve
+considerable width of chest and muscular strength.</p>
+
+<h3>POINTERS.</h3>
+
+<p>Man hunted for ages with dogs that he united in a
+pack; but these packs were of a very heterogeneous
+composition, since they included strong dogs, light dogs
+very swift of foot, shepherds' dogs, and others noted for
+acuteness of scent, and even mongrels due to a crossing
+with the wolf. It is from the promiscuousness of all
+these breeds that has arisen our ordinary modern
+dog.</p>
+
+<p>The pointer is of relatively recent creation, and is due
+to the falconers. In our western countries, falconry
+dates from the fourth and fifth centuries, as is proved
+by the capitularies of Dagobert. This art, therefore,
+was not brought to us from the East by the crusaders
+in the twelfth and thirteenth centuries, as stated by Le
+Maout in his Natural History of Birds.</p>
+
+<p>The falconer soon saw the necessity of having a dog
+of nice scent having for its role the finding or hunting
+up of game without pursuing it, in order to permit the
+falcons themselves to enter into the sport. This animal
+was called the bird dog, and was regarded as coming
+
+from various countries, especially from Spain,
+whence the name of spaniel that a breed of pointers
+has preserved. It is quite curious to find that for three
+or four centuries back there have been no spaniels in
+Spain. From Italy also and from southern climes
+comes what is called the <i>bracco</i>, whence doubtless is
+derived the French name <i>braque</i> and English brach.
+Finally the <i>agasse</i> of the Bretons was certainly also
+one of the progenitors of our present pointers. It was,
+says Oppian, a breed of small and very courageous
+dogs, with long hair, provided with strong claws and
+jaws, that followed hares on the sly under shelter of
+vine-stocks and reeds and sportively brought them
+back to their masters after they had captured them.
+We have certainly here the source of our barbets and
+griffons.</p>
+
+<p>Finally the net hunters of the middle ages also contributed
+much to the creation of the pointer, for it is
+to them that we owe the setter. It is erroneously, in
+fact, that certain authors have attributed the creation
+of this dog to hunters with the arquebuse, since
+this weapon did not begin to be utilized in hunting
+until the sixteenth century. Gaston Phoebus, who
+died in 1391, shows, in his remarkable work, that the
+net hunters made use of Spanish setters and that it
+was they who created the true pointer&mdash;the animal that
+fascinates game by its gaze. By the same pull of their
+draw net they enveloped in its meshes both the setter
+and the prey that it held spellbound.</p>
+
+<p>Upon the whole, we see that at the end of the middle
+ages there existed three types of pointers: spaniels,
+brachs and very hairy dogs, that Charles Estienne,
+in his Maison Rustique, of the sixteenth century, calls
+barbets. It is again with these three types that are
+connected all the present pointers, which we are going
+to pass rapidly in review.</p>
+
+<p><i>The Brach hounds</i>.&mdash;To-day we reserve the name of
+brachs for all pointers with short hair. The type of
+the old brach still exists in Italy, Spain, the south of
+France and in Germany. It is characterized by its
+large size, its robust form, its large head, its long, flat
+ears, its square muzzle separated from the forehead by
+a deep depression, its large nose, often double (that
+is to say, with nostrils separated by a deep vertical
+groove), its pendent lips, its thick neck, its long and
+strong paws provided with dew claws, both on the fore
+and the hind feet, and its short hair, which is usually
+white and marked with brown or orange-yellow spots.
+The old brach breed has been modified by the breeders
+of different countries, either by hygiene or by crossing
+with ordinary dogs, according to the manner of
+hunting, according to taste, and even according to
+fashion. Thus in England, where "time is money"
+reigns in every thing and where they like to hunt quickly
+and not leisurely, the brach has been rendered
+lighter and swifter of foot and has become the pointer.
+In France, while it has lost a little in size and weight,
+it has preserved its moderate gait and has continued to
+hunt near its master, "under the gun," as they say.
+The same is the case in Spain, Italy and Germany
+even. In France there are several varieties or sub-breeds
+of brach hounds. The old French brach, which
+is nothing more than the old type, preserved especially
+in the south, where it is called the Charles the
+Tenth brach, is about twenty-four inches in height,
+and has a white and a maroon coat, which is somewhat
+coarse. It often has a cleft nose and dew-claws on all
+the feet. The brach of the south scarcely differs from
+the preceding except in color. Its coat has a white
+ground covered with pale orange blotches and spots
+of the same color. The St. Germain brach is finer
+bred, and appears to be a pointer introduced into
+France in the time of Charles X. It has a very fine
+skin, very fine hair of a white and orange color. The
+Bourbon brach has the characters of the old French
+brach, with a white coat marked here and there with
+large brown blotches, and the white ground spotted
+with the same color; but what particularly characterizes
+this dog is that it is born with a stumpy tail, as if
+three-quarters of it had been chopped off. The Dupuy
+brach is slender and has a narrow muzzle, as if it had
+some harrier blood in its veins. It is white, with large
+dark maroon blotches. The Auvergne brach resembles
+the southern brach, but has a white and black
+coat spotted with black upon white. The pointer, or
+English brach (Fig. 3), descends from the old Spanish
+brach, but has been improved and rendered lighter and
+much swifter of foot by the introduction of the blood
+of the foxhound into its veins, according to the English
+cynegetic authors themselves. The old pointer
+was of a white and orange color, and was indistinguishable
+from our St. Germain. The pointer now fancied
+is white and maroon and has a stronger frame than the
+pointer of twenty years ago. The Italian brachs are
+heavy, with lighter varieties, usually white and orange
+color, more rarely <i>roan</i>, and provided with dew-claws,
+this being a sign of purity of breed according to Italian
+fanciers. The German brachs are of the type of the
+old brach, with a stiff white and maroon coat, the latter
+color being so extensively distributed in spots on
+the white as to make the coat very dark.</p>
+
+<p class="ctr">
+<img src="images/5-fig3.png" alt="FIG 3.--POINTER." title="">
+<br clear="all" />FIG 3.&mdash;POINTER.</p>
+
+<p><i>Spaniels</i>.&mdash;The old type of spaniel has nearly disappeared,
+yet we still find a few families of it in France,
+especially in Picardy and perhaps in a few remote parts
+of Germany. The old spaniel was of the same build as
+the brach, and differed from it in that the head, while
+being short-haired, was provided with ears clothed with
+long, wavy hair. The same kind of hair also clothed
+the whole body up to the tail, where it constituted a
+beautiful tuft. The Picard spaniel is a little lighter
+than the old spaniel. It has large maroon blotches upon
+a white ground thickly spotted with maroon, with a
+touch of flame color on the cheeks, over the eyes, and
+on the legs. The Pont-Andemer spaniel is a Norman
+variety, with very curly hair, almost entirely maroon
+colored, the white parts thickly spotted with a little
+color as in the Picard variety, and a characteristic forelock
+on the top of the head.</p>
+
+<p class="ctr"><a href="./images/5-fig4.png">
+<img src="images/5-fig4-th.jpg" alt="FIG 4.--ENGLISH SETTERS." title="">
+</a><br clear="all" />FIG 4.&mdash;ENGLISH SETTERS.</p>
+
+<p>In England, the spaniel has given rise to several varieties.
+In the first place there are several sub-breeds of
+setters, viz.: The English setter, still called laverack,
+which has large black or orange-colored blotches on
+the head, the rest of the body being entirely white,
+with numerous spots of the same color as the markings
+on the head (Fig. 4); the Irish setter, which is entirely
+of a bright yellowish mahogany color; and the Gordon
+setter, which is entirely black, with orange color on
+the cheeks, under the throat, within and at the extremity
+of the limbs (Fig. 5). Next come the field spaniels,
+a group of terrier spaniels, which includes the Clumber
+spaniel, which is white and orange color; the Sussex
+spaniel, which is white and maroon; the black spaniel,
+which is wholly black; and the cocker, which is the
+smallest of all, and is entirely black, and white and
+maroon, or white and orange-colored, or tricolored.</p>
+
+<p class="ctr">
+<img src="images/6-fig5.png" alt="FIG 5.--GORDON SETTER." title="">
+<br clear="all" />FIG 5.&mdash;GORDON SETTER.</p>
+
+<p><i>Barbets and Griffons</i>.&mdash;To this latter category belong
+the dogs, <i>par excellence</i>, for hunting in swamps. The
+barbets are entirely covered with long curly hair, like
+the poodles, which are directly derived from them.
+They are white or gray, with large black or brown
+blotches. The griffons differ from the poodles in their
+coarse and stiff hair, which never curls. They have
+large brown blotches upon a white ground, which is
+much spotted or mixed, as in the color of the hair
+called roan. There is an excellent white and orange-colored
+variety. The griffons, neglected for a long
+time on account of the infatuation that was and is still
+had for English hunting dogs, are being received again
+with that favor which they have never ceased to be the
+object of in Germany and in Italy (where they bear the
+name of <i>spinone</i>). Breeders of merit, such as Mr. Korthals,
+in Germany, and Mr. E. Boulet, in France, are
+endeavoring to bring them into prominence (Fig. 6). Finally,
+we reckon also among hunting dogs some very
+happy crosses between the spaniels and the barbets,
+which in England are called retrievers or water
+spaniels.&mdash;<i>P. Megnin, in La Nature</i>.</p>
+
+<p class="ctr">
+<img src="images/6-fig6.png" alt="FIG 6.--COARSE HAIRED GRIFFON." title="">
+<br clear="all" />FIG 6.&mdash;COARSE HAIRED GRIFFON.</p>
+
+<a name="Footnote_1"></a><a href="#FNanchor_1">[1]</a><div class="note">Les Races des Chiens, in La Bibliotheque de l'Eleveur.</div>
+
+<hr />
+
+<a name="pisc-1"></a><h2>RESTOCKING THE SEINE WITH FISH.</h2>
+
+<p>A few days ago, at Bougival, a short distance below
+the dam of the Marly machine, there were put into
+water 40,000 fry of California trout and salmon, designed
+to restock the Seine, which, in this region, has
+been depopulated by the explosions of dynamite which
+last winter effected the breaking up of the ice jam
+that formed at this place.</p>
+
+<p class="ctr"><a href="./images/6-a.png">
+<img src="images/6-a-th.jpg" alt="RESTOCKING THE SEINE WITH FISH." title="">
+</a><br clear="all" />RESTOCKING THE SEINE WITH FISH.</p>
+
+<p>The operation, which is quite simple in itself, attracted
+a large number of inquisitive people by reason
+of the exceptional publicity given to the conflict provoked
+by a government engineer, who, under the pretext
+that he had not been consulted, made objections
+to the submersion of the little fish. As well known,
+the affair was terminated by a sharp reprimand from
+Mr. Yves Guyot, addressed to his overzealous subordinate.</p>
+
+<p>It would have been a great pity, moreover, if this interesting
+experiment had not taken place, and had not
+come to corroborate the favorable results already obtained.</p>
+
+<p>In three years the California salmon reaches a weight
+of eleven pounds, and, from this time, is capable of reproduction.
+Its flesh is delicious, and comparable to
+that of the trout, the development of which is less rapid,
+but just as sure.</p>
+
+<p>The fry put into the water on Sunday were but two
+months old. The trout were, on an average, one and a
+half inches in length, and the salmon two and three-quarter
+inches. They were transported in three iron
+plate vessels, weighing altogether, inclusive of the
+water, 770 lb., and provided with air tubes through
+which, during the voyage, the employes, by means of
+pumps, assured the respiration of the little fish.</p>
+
+<p>Our engraving represents the submersion at the
+moment at which the cylinders (of which the temperature
+has just been taken and compared with that of
+the Seine, in order to prevent too abrupt a transition
+for the fry) are being carefully let down into the river.&mdash;<i>L'Illustration</i>.</p>
+
+<hr />
+
+<p>Figures show that the consumption of iron in general
+construction&mdash;other than railroads&mdash;in this country
+has grown from a little more than a million and a half
+of tons in 1879 to more than six million tons in 1889.
+Much of this increase has gone into iron buildings. By
+using huge iron frames and thin curtain walls for each
+story supported thereon, as is done in a building going
+up on lower Broadway, New York city, a good deal of
+space can be saved.</p>
+
+<hr />
+<a name="nav-1"></a><h2>MODERN ARMOR.</h2>
+
+<h3>By F.R. BRAINARD, U.S.N.</h3>
+
+<p>The building of a navy, which has been actively
+going on for the past few years, has drawn public attention
+to naval subjects, and recent important experiments
+with armor plates have attracted large attention,
+hence it may not be amiss to give a description
+of the manufacture and testing of armor. It would be
+interesting to wade through the history of armor,
+studying each little step in its development, but we
+shall simply take a hasty glance at the past, and then
+devote our attention to modern armor and its immediate
+future.</p>
+
+<p>Modern armor has arrived at its present state of development
+through a long series of experiments. These
+experiments have been conducted with great care and
+skill, and have been varied from time to time as the
+improvements in the manufacture of materials have
+developed, and as the physical laws connected with
+the subject have been better understood. There has
+been very little war experience to draw from, and
+hence about all that is now known has been acquired
+in peaceful experiments.</p>
+
+<p>The fundamental object to be obtained by the use of
+armor is to keep out the enemy's shot, and thus protect
+from destruction the vulnerable things that may
+be behind it. The first serious effort to do this dates
+with the introduction of iron armor. With this form
+of armor we have had a small amount of war experience.
+The combat of the Monitor and Merrimac, in
+Hampton Roads, in May, 1862, not only marked an
+epoch in the development of models of fighting ships,
+but also marked one in the use of armor. The Monitor's
+turret was composed of nine one-inch plates of
+wrought iron, bolted together. Plates built in this
+manner form what is known as laminated armor.
+(See Fig. 1.)
+<img src="images/7-fig1.png" align="left" alt="Fig. 1. Laminated" title="">
+The side armor of the hull was composed
+of four one-inch plates. The Merrimac's casemate was
+composed of four one-inch plates or two two-inch plates
+backed by oak. The later monitors had laminated armor
+composed of one-inch plates. The foregoing, with
+the Albemarle and Tennessee rams under the Confederate
+flag, are about the sum of our practical experience
+in the use of armor.</p>
+
+
+<p>European nations took up the subject of armor and
+energetically conducted experiments which have cost
+large sums of money, but have given much valuable
+data. For a long time wrought iron was the only material
+used for armor, and the resisting power depending
+on the thickness; and the caliber and penetration
+of guns rapidly increasing, it was not long before a
+point was reached where the requisite thickness made
+the load of armor so great that it was impracticable for
+a ship to carry it. The question then arose as to what
+were the most important parts of a ship to protect.
+The attempted solutions of this question brought out
+various systems of distributions.</p>
+
+<p>Armored ships were formerly of two classes; in one
+the guns were mounted in broadside, in the other in
+turrets. Every part of the ship was protected with
+iron to a greater or less thickness. In more modern
+ships the guns are mounted in an armored citadel, in
+armored barbettes or turrets, the engines, boilers and
+waterline being the only other parts protected. There
+may be said to be three systems of armor distribution.
+The belt system consists in protecting the whole waterline
+by an armored belt, the armor being thickest
+abreast of the engines and boilers. The guns are protected
+by breastworks, turrets or barbettes, the other
+parts of the ship being unprotected. The French use
+the belt system, and our own monitors may be classed
+under it. The central citadel system consists in armoring
+that part of the waterline which is abreast of
+the engines and boilers. Forward and aft the waterline
+is unprotected, but a protective deck extends from
+the citadel in each direction, preventing the projectiles
+from entering the compartments below. The hull is
+divided into numerous compartments by water-tight
+bulkheads, and, having a reserve of flotation, the stability
+of the ship is not lost, even though the parts
+above the protective deck, forward and aft, be destroyed
+or filled with water. The guns are protected
+by turrets or barbettes. The deflective system consists
+in inclining the armor, or in so placing it that it
+will be difficult or impossible to make a projectile
+strike normal to the face of the plate. A plate that is
+inclined to the path of a projectile will, of course, offer
+greater resistance to penetration than one which is
+perpendicular; hence, when there is no other condition
+to outweigh this one, the armor is placed in such a
+manner as to be at the smallest possible angle with
+the probable path of the projectile. This system is designed
+to cause the projectile to glance or deflect on
+impact. Deflective armor should be at such an angle
+that the projectiles fired at it cannot bite, and hence
+the angle will vary according to the projectile most
+likely to be used. In the usual form of deflective deck
+the armor is at such a small inclination with the horizon
+that it becomes very effective. Turret and
+barbette armor may be considered as deflective armor.
+The term inclined armor denotes deflective armor
+that is inclined to the vertical. The kinds of armor
+that are in use may be designated as rolled iron, chilled
+cast iron, compound, forged and tempered steel, and
+nickel steel. Iron armor consists of wrought iron
+plates, rolled or forged, and of cast iron or chilled cast
+iron, as in the Gruson armor. Compound armor consists
+of a forged combination of a steel plate and an
+iron plate. Steel armor consists of wrought steel
+plates. Nickel-steel armor consists of plates made
+from an alloy of nickel and steel.</p>
+
+<p>I have spoken above of laminated armor. To secure
+the full benefit of this kind, the plates must be neatly
+fitted to each other; the surfaces must make close contact.
+This requires accurate machining, and hence is
+expensive. To overcome this point sandwiched armor
+was suggested. This consists in placing a layer of wood
+between the laminations, as shown in Fig. 2.
+<img src="images/7-fig2.png" align="right" alt="Fig. 2." title="">
+It was
+found that laminated and sandwiched armor gave very
+much less resisting power than solid rolled plates
+of the same thickness. Wrought iron armor is made
+under the hammer or under the rolls, in the ordinary
+manner of making plates, and has been exhaustively
+studied and experimented with&mdash;more so than any
+other form of armor.</p>
+
+
+<p>Chilled cast iron armor is manufactured by Gruson,
+in Germany, and is used in sea coast defense forts of
+Europe.</p>
+
+<p>In 1867 several compound plates were made by Chas.
+Cammell &amp; Co., of Sheffield, England, and were tested
+at Shoeburyness, in England, and at Tegel, in Russia.
+These plates were made by welding slabs of steel to
+iron; but the difficulties were so great that the idea
+was abandoned for the time.</p>
+
+<p>
+<img src="images/7-fig3.png" align="left" alt="Fig. 3." title="">
+
+<img src="images/7-fig4.png" align="right" alt="FIG. 4." title="">
+<br clear="all" /></p>
+
+<p>Compound armor, as now manufactured, is of two
+types: Wilson's patent, a backing of rolled iron, faced
+with Bessemer steel; Ellis' patent, a backing of rolled
+iron, faced with a plate of hard rolled steel, cemented
+with a layer of Bessemer steel. Both these kinds are
+manufactured in England and France in sizes up to
+fifty tons weight. The Wilson process is used at the
+works of Messrs. Cammell &amp; Co., of Sheffield, England,
+and the Ellis process at the Atlas Works of Sir John
+Brown &amp; Co., of the same place. These are the two
+leading manufacturers of compound plate.</p>
+
+
+<p>The method employed by Wilson in making compound
+plate is to first make a good wrought iron
+plate. To the surface of this and along each side of
+the length of the plate are fixed two small channel
+irons, as shown in Fig. 5.
+<img src="images/7-fig5.png" align="left" alt="Fig. 5." title="">
+The plate is then raised to
+a welding heat in a gas furnace, and transferred to an
+iron flask or mould. Wedges are driven in between
+the back of the plate and the side of the mould, thus
+forcing the channel irons up snug against the opposite
+side of the mould. Moulding sand is then packed
+around the back and sides of the plate (see Fig. 6).
+<img src="images/7-fig6.png" align="right" alt="Fig. 6." title="">
+The
+mould is lowered in a vertical position into a pit.
+Molten steel, manufactured by either the Siemens-Martin
+or Bessemer process, is then poured in through
+a trough that forms several streams, and forms the
+hard face of the plate. The molten steel as it runs
+down cleans the face of the wrought iron plate, scoring
+it in places, and, being of much higher temperature,
+the excessive heat carbonates the iron to a depth
+of one-eighth to three-sixteenths of an inch, forming
+a zone of mild steel between the hard steel and soft
+iron. The mould is placed in a vertical position to insure
+closeness of structure and the forcing of gases
+out of the steel. After solidifying, the whole plate is
+pressed, and passed through the rolls to obtain
+thorough welding. It is then bent, planed, fitted,
+tempered, and annealed to remove internal strains.</p>
+
+<p>In 1887, Wilson took out a patent for improvements
+in his process of making compound plates. In this
+method of manufacture he takes a wrought iron,
+fibrous plate, fifteen inches thick, built up from a
+number of thin plates. While hot from the forging
+press, he places this plate in an iron mould (see Fig. 7)
+<img src="images/7-fig7.png" align="left" alt="Fig. 7." title="">
+about 28 inches deep, and upon it runs "ingot iron"
+or very mild steel to a depth of thirteen inches. In
+this form of mould the plate rests on brickwork, and is
+held in place by two grooved side clamps or strips which
+are caused to grip the plate by means of screws which
+extend through the sides of the mould. After solidifying,
+the plate, which is twenty-eight inches thick, is
+reheated and rolled down to eighteen inches. This is
+the iron backing of the finished plate, and it is again
+put in the iron mould and heated, when a layer of hard
+steel is run on the exposed surface of the original
+wrought iron plate to a depth of eight inches. This
+makes a plate about twenty-eight inches thick. It is
+taken from the mould, reheated, rolled, hammered or
+pressed down to twenty inches. After cooling, it is
+bent, planed, and fitted as desired, then tempered and
+annealed to relieve internal strains.</p>
+
+
+
+<p>The method employed by Ellis in making compound
+plates is to take two separate plates, one of good
+wrought iron and one of hard forged steel, placing the
+forged steel plate on the wrought iron plate, keeping
+them separate by a wedge frame or berm of steel
+around three sides, and placing small blocks of steel at
+various points near the middle of the plates (see Fig. 8).
+<img src="images/7-fig8.png" align="right" alt="Fig. 8." title="">
+These blocks are called distance blocks. After covering
+all the exposed steel surfaces with ganister, the
+plates are put in a gas furnace and heated to a welding
+heat. They are then lowered into a vertical iron pit
+with the open side uppermost. The plates are held in
+position by hydraulic rams, which also prevent bulging.
+Molten steel of medium softness is then poured
+into the space between the plates, by means of a distributing
+trough having holes in the bottom, and after
+this has solidified, the whole plate is placed under the
+hydraulic press and reduced about twenty per cent. in
+thickness. The plate is then passed through the rolls,
+bent, planed, fitted, tempered, and annealed to reduce
+internal strains.</p>
+
+<p>In heating the compound plates for rolling, the plate
+is placed in the furnace with the steel face down, so
+that the iron part gets well heated and the steel does
+not become too hot. Great care must be taken not to
+overheat the plate, and in working, many passes are
+given the plate with small closings of the rolls. The
+steel part of a compound plate is usually about one
+third of the full thickness of the plate.</p>
+
+<p>Forged steel armor, tempered in oil, is fabricated at
+Le Creusot, France, by Schneider &amp; Co., using open-hearth
+steel, and forging under the 100 ton hammer.
+
+The ingots are cast, with twenty-five per cent. sinking
+head and are cubical in form. The porter bar is attached
+to a lug on one side of the ingot. By means of
+a crane with a curved jib which gives springiness under
+the hammer, the ingot is thrust into the heating
+furnace. On arriving at a good forging heat it is
+swung around to the 100 ton hammer, under which it is
+worked down to the required shape. A seventy-five
+ton ingot requires about eight reheatings before being
+reduced to shape. Having been reduced to shape, the
+plate is carefully annealed, then raised to a high tempering
+heat, and the face tempered in oil. It is reannealed
+to take out the internal strains, care being taken
+not to reduce the face hardness more than necessary.
+The Schneider process of tempering is based upon the
+utilization of the absorption of heat caused by the fusing
+or melting of a solid substance, and of the fact
+that so long as a solid is melting or dissolving in a
+liquid substance, the liquid cannot get appreciably
+hotter, except locally around the heating surface. The
+body to be hardened is plunged at the requisite temperature
+into a bath containing the solid melting body,
+or is kept under pressure in the solid material of low
+melting point until the required extraction of heat has
+taken place, more solid material being added if necessary
+as that originally present melts and dissolves.</p>
+
+<p>Nickel steel armor is made in a similar manner to
+the steel plates, the material used in casting the ingot
+being an alloy of nickel and steel containing between
+three and four per cent. of nickel.</p>
+
+<p>The Harvey process of making armor consists in taking
+an all-steel plate and carbonizing the face. This
+carbonizing process is very similar to the cementation
+process of producing steel, and by it the face of the
+plate is made high in carbon and very hard.</p>
+
+<p>The system invented by Sir Joseph Whitworth, of
+Manchester, England, consists in what might be called
+scale armor. A section of a sample of the armor represents
+four plates. The outer layer, one inch thick, is
+composed of steel of a tensile strength of 80 tons per
+square inch; the second layer, one inch thick, of steel
+whose tensile strength is 40 tons per square inch; the
+third and fourth layers, each one-half inch thickness,
+of mild steel. The outer layer is in small squares of
+about ten inches on a side, and is fastened to the second
+layer by bolts at the corners and one in the middle of
+each square. The surface is flush. (See Fig. 9.)
+<img src="images/8-fig9.png" align="right" alt="Fig. 9." title="">
+The
+end sought by the above system is to break up the shot
+by the hard steel face and to restrict any starring or
+cracking of the metal to the limit of the squares or
+scales struck. The bolts are of high carbon and are
+extremely hard steel.
+</p>
+
+<p>Armor plates must often be bent or curved to single
+or double curvature and sometimes to a warped surface
+to fit the form of the ship. There are several methods
+of bending plates. One method employs a cast iron
+slab of the required form, which is placed on the piston
+of a hydraulic press. The armor plate is placed
+face down on this slab, and on top of the plate are laid
+packing blocks of cast iron, of such sizes and shapes as
+to conform to the required curve. These blocks take
+against the upper table of the press, when the piston
+is forced up, and the hot plate is thus dished to the
+proper form.</p>
+
+<p>In the French method of bending, an anvil or bed
+plate of the required curve is used, and the armor plate
+is forced to take the curve by being hammered all over
+its upper surface with a specially designed steam
+hammer.</p>
+
+<p>The edges of the plate are trimmed by large, powerful
+slotting machines or circular saws; the latter, however,
+operate in exactly the same manner as a slotter,
+except that there is no return motion to the tool. Each
+tooth of the saw is but a slotting tool, and these teeth
+are, by screws, rendered capable of being nicely adjusted
+in the circumference of the saw.</p>
+
+<p>The plates are fastened to the hulls and backing by
+heavy bolts, varying in size according to the weight of
+the individual plate. For the 6,000 ton armored ships,
+these bolts are from 2.75 to 3.1 inches in diameter and
+from 18.45 to 23 inches in length. They are tapped
+two or three inches into the armor and do not go
+through the plate. They pass through wrought iron
+tubes in the backing and set up with cups, washers
+and nuts against the inner skin of the ship.</p>
+
+<p>At steel works where plates for our new navy are
+being manufactured, there are inspectors who look
+after the government's interests. Officers of the navy
+are detailed for this work, and their duty is to watch
+the manufacture of plates through each part of the
+process and to see that the conditions of the specifications
+and contract are complied with.</p>
+
+
+<p>The inspection and testing of armor plates consists
+in examining them for pits, scales, laminations, forging
+cracks, etc., in determining the chemical analysis of
+specimens taken from different parts, in determining
+the physical qualities of specimens taken longitudinally
+and transversely, and the ballistic test. Specifications
+for these different tests are constantly undergoing
+change, and it would be impossible to state, with exactness,
+what the requirements are or will be in the near
+future. The ballistic test is the important one,
+and is made by taking one plate of a group and subjecting
+it to the fire of a suitable gun. The other tests
+are simply to insure, as far as practicable, that all the
+other plates of the group are similar to and are capable
+of standing as severe a ballistic test as the test plate.</p>
+
+<p>The following will give an idea of the ballistic test
+as prescribed by the Bureau of Ordnance, Navy Department.
+The test plate, irrespective of its thickness,
+is to be backed by thirty-six inches of oak or other
+substantial wood. Near the middle region of the plate an
+equilateral triangle will be marked, each side of which
+will be three and one-half calibers long. The lower
+side of the triangle will be horizontal. Three shots
+will be fired, the points of impact being as near as possible
+the extremities of the triangle. The velocity of
+the shot will be such as to give the projectile sufficient
+energy to just pass through a wrought iron plate of
+equal thickness to the test plate, and through its wood
+backing. The velocity is calculated by the Gavre
+formula:</p>
+
+<p><img src="./images/tex1.png" align="middle" alt=
+"V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}"></p>
+
+<p class="ind">V = the velocity of the projectile in feet per second.<br />
+  a = the diameter of the projectile in inches.<br />
+  w = the weight of the projectile in pounds.<br />
+  E = the thickness of the backing in inches.<br />
+  e = the thickness of the plate in inches.<br />
+</p>
+
+<p>Using the above formula we can make out a table as follows:</p>
+
+<pre>
+-------+-------+-------------+-------+-------+------+---------+
+Plate. |Backi'g| Gun, service|  w,   |  a,   |  V.  | Energy, |
+Inches.|Inches.| shot.       |Pounds.|Inches.| f. 8.| Impact. |
+       |       |             |       |       |      | f. tons.|
+-------+-------+-------------+-------+-------+------+---------+
+  6    |  36   |   6" B.L.R. |  100  |  5.96 | 1389 |  1337   |
+  7    |  36   |   6"   "    |  100  |  5.96 | 1528 |  1619   |
+  8    |  36   |   8"   "    |  250  |  7.96 | 1213 |  2550   |
+  9    |  36   |   8"   "    |  250  |  7.96 | 1308 |  2966   |
+ 10    |  36   |   8"   "    |  250  |  7.96 | 1399 |  3390   |
+ 11    |  36   |   8"   "    |  250  |  7.96 | 1489 |  3839   |
+ 12    |  36   |  10"   "    |  500  |  9.96 | 1247 |  5386   |
+ 13    |  36   |  10"   "    |  500  |  9.96 | 1315 |  5987   |
+ 14    |  36   |  10"   "    |  500  |  9.96 | 1381 |  6608   |
+ 15    |  36   |  12"   "    |  850  | 11.96 | 1215 |  8699   |
+ 16    |  36   |  12"   "    |  850  | 11.96 | 1269 |  9710   |
+ 17    |  36   |  12"   "    |  850  | 11.96 | 1332 | 10454   |
+ 18    |  36   |  12"   "    |  850  | 11.96 | 1374 | 11124   |
+ 19    |  36   |  12"   "    |  850  | 11.96 | 1425 | 11965   |
+ 20    |  36   |  12"   "    |  850  | 11.96 | 1476 | 12837   |
+-------+-------+-------------+-------+-------+------+---------+
+</pre>
+
+<p>No projectile or fragment of the plate or projectile
+must get wholly through the plate and backing. The
+plate must not break up or give such cracks as to expose
+the backing, previous to the third shot.</p>
+
+<p>The penetration of projectiles of different forms
+into various styles of armor has been very thoroughly
+studied and many attempts have been made to bring
+the subject down to mathematical formulæ. These
+formulæ are based on several suppositions, and agree
+very closely with results obtained in actual experiments,
+but there are so many varying conditions that
+it is extremely doubtful if any formulæ will ever be
+written that will properly express the penetration.</p>
+
+<p>Many different forms have been given to the heads
+of projectiles, as flat, ogival, hemispherical, conoidal,
+parabolic, blunt trifaced, etc.</p>
+
+<p>The flat headed projectile has the shape of a right
+cylinder, and acts like a punch, driving the material of
+the armor plate in front of it. These projectiles are
+especially valuable when firing at oblique armor, for
+they will bite or cut into the armor when striking at
+an angle of thirty degrees.</p>
+
+<p>The ogival head acts more as a wedge, pushing the
+metal aside, and generally will give more penetration
+in thick solid plates than the flat headed projectile.
+The ogival head is usually designed by using a radius
+of two calibers.</p>
+
+<p>The hemispherical, conoidal, parabolic and blunt
+trifaced all give more or less of the wedging effect.
+The blunt trifaced has all the good qualities of the ogival
+of two calibers. It bites at a slightly less angle,
+and the three faces start cracks radiating from the
+point of impact.</p>
+
+<p>Forged steel is the best material for armor-piercing
+projectiles, but many are made of chilled cast iron, on
+account of its great hardness and cheapness.</p>
+
+<p>The best weight for a projectile is found by the formula</p>
+
+<pre>
+        w = d³ (0.45 to 0.5)
+</pre>
+
+<p>w being the weight in pounds, d the diameter in inches
+and 0.45 to 0.5 having been determined by experiment.</p>
+
+<p>With a light projectile we get a flat trajectory, and
+accuracy at short ranges is increased. With a heavy
+projectile the resistance of the air has less effect and
+the projectile is advantageously employed at long ranges.</p>
+
+<p>In the following formulæ, used in calculating the
+penetration of projectiles in rolled iron armor,</p>
+
+<pre>
+  g = the force of gravity.
+  w = the weight of projectile in pounds.
+  d = the diameter of projectile in inches.
+  v = the striking velocity in feet per second.
+  P = the penetration in inches.
+</pre>
+
+<p>Major Noble, R.A., gives</p>
+
+<p><img src="./images/tex2.png" align="middle" alt=
+"P = \sqrt[1.6]{\frac{w \ v^2}{\pi \  g \  d \ 11334.4}}"></p>
+
+<p>U.S. Naval Ordnance Proving Ground uses</p>
+
+<p><img src="./images/tex3.png" align="middle" alt=
+"P = \sqrt[2.035]{\frac{w \ v^2}{\pi \  g \  d \ 3852.8}}"></p>
+
+<p>Col. Maitland gives</p>
+
+<p><img src="./images/tex4.png" align="middle" alt=
+"P = \frac{w \ v^2}{g \  d^2 \ 16654.4}"></p>
+
+<p>Maitland's latest formula, now used in England, is</p>
+
+<p><img src="./images/tex5.png" align="middle" alt=
+"P = \frac{v}{608.3} \sqrt{\frac{w}{d}} - 0.14 \ d"></p>
+
+
+<p>General Froloff, Russian army, gives</p>
+
+<p><img src="./images/tex6.png" align="middle" alt=
+"P = \frac{w \ v}{d^2 \ 576}"></p>
+
+<p>for plates less than two and one-half inches thick, and</p>
+
+<p><img src="./images/tex7.png" align="middle" alt=
+"P = \frac{w \ v}{d^2 \ 400} - 1.5"></p>
+
+<p>for plates more than two and one-half inches thick.</p>
+
+<p>If &theta; be the angle between the path of the projectile
+and the face of the plate, then v in the above formulæ
+becomes v sin &theta;.</p>
+
+<p>When we come to back the plates, their power to
+resist penetration becomes greater, and our formula
+changes. The Gavre formula, given above, is used to
+determine the velocity necessary for a projectile to pass
+entirely through an iron plate and its wood backing.</p>
+
+<p>Compound and steel armor are said to give about
+29 per cent. more resisting power than wrought iron,
+but in one experiment at the proving ground, at Annapolis,
+a compound plate gave over 50 per cent. more
+resisting power than wrought iron.</p>
+
+<p>The Italian government, after most expensive and
+elaborate comparative tests, has decided in favor of
+the Creusot or Schneider all-steel plates, and has
+established a plant for their manufacture at Terni,
+near Rome.</p>
+
+<p>The French use both steel and compound plates;
+the Russians, compound; the Germans, compound;
+the Swedes and Danes use both. Spain has adopted
+and accepted the Creusot plate for its new formidable
+armored vessel, the Pelayo; and China too has recently
+become a purchaser of Creusot plates.</p>
+
+<p>Certain general rules may be laid down for attacking
+armor. If the armor is iron, it is useless to attack with
+projectiles having less than 1,000 feet striking velocity
+for each caliber in thickness of plate. It is unadvisable
+to fire steel or chilled iron filled shells at thick
+armor, unless a normal hit can be made. When perforation
+is to be attempted, steel-forged armor-piercing
+shells, unfilled, should be used. They may be filled if
+the guns are of great power as compared to the armor.
+Steel and compound armor are not likely to be pierced
+by a single blow, but continued hammering may break
+up the plate, and that with comparatively low-powered
+guns.</p>
+
+<p>Wrought iron must be perforated, and hard armor,
+compound or steel, must be broken up. Against wrought
+iron plates the projectile may be made of chilled cast
+iron, but hard armor exacts for its penetration or
+destruction the use of steel, forged and tempered. Against
+unarmored ships, and against unarmored portions of
+ironclads, the value of rapid-firing guns, especially
+those of large caliber, can hardly be overestimated.</p>
+
+<p>The relative value of steel and compound armor is
+much debated, and at present the rivalry is great, but
+the weight of evidence and opinion seems to favor the
+all-steel plate. The hard face of a compound plate is
+supposed to break up the projectile, that is, make the
+projectile expend its energy on itself rather than upon
+the plate, and the backing of wrought iron is, by its
+greater ductility, to prevent the destruction of the
+plate. It seems probable that these two systems will
+approach each other as the development goes on. An
+alloy of nickel and steel is now attracting attention
+and bids fair to give very good results.</p>
+
+<p>The problem to be solved, as far as naval armor is
+concerned, is to get the greatest amount of protection
+with the least possible weight and volume, and this
+reduction of weight and volume must be accomplished,
+in the main, by reducing the thickness of the plates
+by increasing the resisting power of the material. In
+the compound plate great surface hardness is readily
+and safely attained, but it has not yet been definitely
+determined what the proper proportionate thickness
+of iron and steel is.</p>
+
+<p>A considerable thickness of steel is necessary to aid,
+by its stiffness, in preventing the very ductile iron from
+giving back to such an extent as to distort the steel
+face and thus tear or separate the parts of the plate.
+The ductile iron gives a very low resisting power, its
+duty being to hold the steel face up to its work. If
+now we substitute a soft steel plate in the place of the
+ductile iron, we will get greater resisting power, but
+our compound plate then becomes virtually an all-steel
+one, only differing in process of manufacture. The
+greatest faults of the compound plate are the imperfect
+welding of the parts and the lack of solidity of the
+iron. When fired at, the surface has a tendency to
+chip.</p>
+
+<p>In the all-steel plate we have the greatest resisting
+power throughout, but there are manufacturing difficulties,
+and surface hardness equal to that of the compound
+plate has not been obtained. The manufacturing
+difficulties are being gradually overcome, and
+artillerists are in high hopes that the requisite surface
+hardness will soon be obtained.</p>
+
+<p>The following may be stated as well proved:</p>
+
+<p class="ind">1. That steel armor promises to replace both iron and compound.<br />
+<br />
+2. That projectiles designed for the piercing of hard
+armor must be made of steel.<br />
+<br />
+3. That the larger the plate, the better it is able
+to absorb the energy of impact without injury to itself.<br />
+<br />
+4. That the backing must be as rigid as possible.<br />
+</p>
+<hr />
+
+[FROM ENGINEERING.]
+
+<a name="ce-1"></a><h2>THE COMPRESSED AIR SYSTEM OF PARIS.</h2>
+
+<p>The demand for compressed air as a motive power is
+constantly increasing in Paris; the company, according
+to its official reports, is financially prosperous, and
+it seems difficult to understand how it should continue
+as an actively going concern, unless it at all events
+paid its way. The central station of St. Fargeau,
+originally started on modest lines, for maintaining a
+uniform time by pneumatic pressure throughout Paris,
+has grown rapidly to very large proportions, though it
+has never been able to supply the demand made on it
+for power; and at the present time a second and still
+larger station is being constructed in another part of
+Paris. We confess that we do not understand why such
+large sums of money should continue to be spent if the
+
+enterprise is not commercially a sound one, nor how men
+of such eminence in the scientific world as Professor
+Riedler should, without hesitation, risk their reputation
+on the correctness of the system, if it were the idle
+dream of an enthusiast, as many persons&mdash;chiefly those
+interested in electric transmission&mdash;have declared it
+to be.</p>
+
+<p class="ctr"><a href="./images/9-fig1.png">
+<img src="images/9-fig1-th.jpg" alt="Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION" title=""></a><br clear="all" />Fig. 1.&mdash;MAP OF PARIS WITH ST. FARGEAU STATION</p>
+
+<p>In describing the developments that have taken
+place during the last two years, we shall confine ourselves
+entirely to the details of a report recently made
+on the subject by Professor Riedler. As soon as it
+became evident that a very largely increased installation
+was necessary, it was determined that the new central
+station should be as free as possible from the defects
+of the first one. These defects, which were the natural
+results of the somewhat hasty development of an
+experimental system, were of several kinds. In the first
+place, so large a growth had not been contemplated,
+
+and the extensions were made more or less piecemeal,
+instead of being on a regular plan; the location of the
+central station itself was very unfavorable, both as regards
+the facilities for obtaining coal and other supplies;
+the cost of water was excessive, and the amount
+available, inadequate.</p>
+
+<p>This evil was partly remedied by elaborate arrangements
+for cooling the injection water so that it could
+be repeatedly used, a device costly and ineffective,
+and resulting in extravagant working, to say nothing
+of the high charges made by the Paris company for
+supplying water. To these drawbacks had to be added
+others of an even more serious character. The engines
+first laid down were not economical, and the compressors
+employed gave but a very inferior result; with
+each extension of the plant, the efficiency of both engines
+and compressors was increased, the most satisfactory,
+we believe, having been those supplied by the
+
+Societe Cockerill, and one of which was exhibited at the
+Paris exhibition in 1889. Still it was clearly recognized
+that much better results were possible, results which
+Professor Riedler claims have been attained and which
+will be embodied in the new installation now in progress.</p>
+
+<p>This central station is located on the left bank of the
+Seine, close to the fortifications, opposite Vincennes
+and not far from the terminal stations of the Orleans
+and the Paris, Lyons, and Mediterranean Railways;
+the plan, Fig. 1, shows the position. The works are
+separated from the river by the quay, over which a
+bridge will be constructed for the transfer of coal from
+the landing stages belonging to the company, into the
+works; as will be readily seen from the plan, it would
+be quite easy to run junction lines to the two adjacent
+railways, but with all the advantages given by water
+carriage, it was considered unnecessary to incur the expense.
+The river also affords a constant and unlimited
+water supply, so that none of the difficulties existing
+at St. Fargeau Station in imperfect condensation and
+cooling will be met with.</p>
+
+<p>The new installation, called the Central Station of
+the Quai de la Gare, is laid out on a very large scale,
+the total generating energy provided for being no less
+than 24,000 horse power; of this it is intended that
+8,000 horse power will be in operation this year, and an
+extension of 10,000 horsepower in 1892; the power now
+in course of completion comprises four engines of 2,000
+horse power each. Four batteries of boilers will provide
+steam for these engines. Figs. 2, 3, and 4 show the first
+section of the installation now in progress; the four
+groups of engines (three-cylinder condensing) are shown
+at 1, 2, 3, and 4; the four groups of boilers ranged behind
+them at F, F; the feed water heaters belonging to
+each group at V V.</p>
+
+<p class="ctr"><a href="./images/9-fig234.png">
+<img src="images/9-fig234-th.jpg" alt="COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS. (FIG. 2,3,4)" title="">
+</a><br clear="all" />COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS. (FIG. 2,3,4)</p>
+
+<p>The end of the building abuts against the Seine, and
+the position of the water conduits for inlet and discharge
+are indicated at C and A respectively. The installation,
+when completed, will include very extensive
+arrangements for transporting and storing coal, and
+the interior of the boiler houses will be furnished with
+an overhead system of rails and carriers for handling
+the coal automatically, as far as possible. All the
+principal mains and steam pipes are made in duplicate,
+not only for greater security, but in order that
+each set of engines and boilers may be connected interchangeably
+without delay. The Seine supplies an
+ample quantity of water, but not in a condition either
+for feeding the boilers, for condensation, or for the air
+compressors.</p>
+
+<p>Special provisions have therefore to be made to
+filter the water efficiently before it is used. For this
+purpose the water is led to a group of four filters (see
+L, Fig. 4); from them it passes into the tanks, JJ, and
+is pumped into the heaters. The filters can be rapidly
+and automatically cleaned by reversing the flow of
+water through them. Figs. 5 and 6 show the general
+form of the type of engine adopted, as well as the engine
+house, some of the mains, etc. They are vertical
+triple-expansion engines, and are being constructed by
+MM. Schneider et Cie, of Creusot, with a guarantee of
+coal consumption not to exceed 1.54 lb. per horse power
+per hour, with a penalty of 2,000 francs for every 100
+grammes in excess of this limit. It is evident that with
+this restricted fuel consumption, a large margin for
+economy will exist at the new works, as compared with
+the St. Fargeau station, where the best engines cannot
+show anything like this result, while some of the earlier
+ones are distinctly extravagant, and the whole installation
+is handicapped with imperfect means of condensation.</p>
+
+<p class="ctr"><a href="./images/9-fig56.png">
+<img src="images/9-fig56-th.jpg" alt="THE NEW COMPRESSED AIR STATION AT
+PARIS. (FIG. 5, 6)" title=""></a><br clear="all" />THE NEW COMPRESSED AIR STATION AT
+PARIS. (FIG. 5, 6)</p>
+
+<p>Moreover, according to Professor Riedler, the consumption
+of steam by the new Schneider engines will
+be only 5.3 kilos. per horse power and per hour as compared
+with some of the large engines requiring 9 kilos.,
+and the Cockerill engines&mdash;using 8 kilos. per hour, not
+to speak of the older motors that are very extravagant
+in the use of steam. The St. Fargeau station is worked
+under a further disadvantage. The constantly increasing
+demand from subscribers taxes the resources of
+the station to their fullest extent, so that practically
+there is no reserve power.</p>
+
+<p>In the new installation the work will be equally constant,
+but care will be taken always to have a sufficient
+reserve. Electric lighting will form a considerable part
+of the duty to be done from this station, and in all
+cases it is intended to work with accumulators, so that
+the resistance to be overcome by the engines, so far as
+this part of the duty is concerned, will be well known
+and uniform. The engineers of the Compressed Air Co.,
+of Paris, have during the last five years acquired an
+experience which could only be attained at a high
+price and at the expense of a certain amount of failure;
+this period, it is claimed, is now passed, and in the
+new installation it is possible to put into practice all
+the valuable lessons learned at St. Fargeau, to say
+nothing of the more favorable natural conditions under
+which the extension is being started and the improvements
+in the compression of the air made by Mr. Popp
+and Professor Riedler, and to which we shall refer
+later.</p>
+
+<p>Chiefly in consequence of the high value of the
+ground, vertical engines were adopted at the new
+station; the proximity to the river made the foundations
+somewhat costly, and the risk of occasional floods
+rendered it desirable to set the level of the engine bedplates
+20 inches above the floor of the building; the
+foundations of the engines are continuous, but are quite
+independent of the building. There are three compressing
+cylinders in each set of engines, one being
+above each steam cylinder. Two of these are employed
+to compress the air to about 30 lb. per square inch,
+after which it passes into a receiver and is cooled; it is
+then admitted into the third or final compressing cylinder
+and raised to the working pressure at which it flows
+into the mains. In the illustrations, h, m, and b are
+the high, intermediate, and low pressure cylinders of
+one set of engines; as will be seen, each cylinder is on a
+separate frame connected by girders; directly above
+the cylinders are the two low and the one high pressure
+air cylinders, b¹, m¹, and h¹ respectively. The former
+deliver the air compressed to the first stage into the
+receiver, T¹ (see Fig. 5), whence it passes into the third
+compression cylinder, and thence by a main into the
+cylinders, R R, which are in direct communication with
+the delivery mains; these mains terminate in the subway,
+T. The water for condensation is brought into
+the engine house by the channel, C, and the condenser
+pumps, a, draw direct from this supply; the discharge
+main back to the river is shown at A. The relative
+positions of the engine and boiler houses are indicated
+in Figs. 2 to 5, where F shows the end of one group of
+boilers; the air supply for the compressors is led from
+the central raised portion, S, of the roof.</p>
+
+<p>Professor Riedler's first experiments in improving
+the efficiency of air compressors were made with one
+of the Cockerill compressors in use at the St. Fargeau
+Station, and considerable difficulty attended this work,
+because the machinery was necessarily kept almost in
+constant operation. These compressors were designed
+by MM. Dubois and Francois, of Seraing. Two of their
+leading features were the delivery of the compressed
+air at as low a temperature as possible, and with a relatively
+high piston speed of about 400 ft. a minute.
+The former object is attained by the injection of a
+very fine water spray at each end of the air cylinder,
+and its rapid removal with each stroke; the free as
+well as the compressed air flows through the same
+passages, one at each end of the cylinder; the inlet
+valves being placed at the side of these passages, and
+the outlet or compressed air valves at the top, the
+compressed air, entering a chamber above the cylinder,
+common to both valves, and passing thence to the reservoir.
+The compressed air valves, which are seven in.
+in diameter, are brought back sharply to their seats at
+each stroke, by a small piston operated by compressed
+air flowing through a by-pass from the chamber. The
+illustrations published by us on page 686 of our forty-seventh
+volume show the construction of these compressors.
+The engravings on page 683 of the same volume
+illustrate the compressors used in a somewhat older
+part of the installation; they were made by M. Blanchod,
+of Vevey, and a passing reference may be made
+to them. The air is admitted through valves in the
+cylinder, and is forced out through spring-loaded
+valves; water is admitted into the cylinder to cool the
+air.</p>
+
+<img src="images/10-fig7.png" align="right" alt="Fig. 7" title="">
+
+<p>Fig. 7 indicates the modification made by Professor
+Riedler in one of the Cockerill compressors: a receiver,
+A, was placed under the two compressing cylinders, B
+and C. The first stage is completed in the large cylinder,
+B, the air being compressed to about 30 lb. per
+square inch; from this it is discharged into the receiver,
+A, through the pipe, B¹, where it meets with a
+
+spray injection that cools it to the temperature of the
+water. The final stage is then effected in the smaller
+cylinder, C, which, drawing the air from the receiver
+through the pipe, C¹, compresses it to about 90 lb. and
+delivers it through the pipe, d, to the mains. We hope
+shortly to publish drawings of this compressor in its
+final form; in its elementary stage Professor Riedler
+claims to have obtained some very remarkable results.
+He says that the waste spaces in his modification were
+much smaller than in the Cockerill compressor, while the
+efficiency of the apparatus was largely increased. The
+actual engine duty per horse power and per hour was
+raised, as a maximum, to 384 cubic feet of air at atmospheric
+pressure, and compressed to 90 lb. per square
+inch, a marked increase on the duty of the compressors
+in use at the St. Fargeau station. The Cockerill compressors
+experimented on at the same time showed a
+maximum duty of 306 cubic feet of air. A considerable
+advantage is claimed in drawing clean and cool air from
+the outside of the building, and beyond the main feature
+of carrying out the compression in two stages, Mr.
+Riedler appears to have shown great skill in introducing
+several minor alterations and improvements in the
+plant.</p>
+
+<p><a href="images/10-fig8910.png">
+<img src="images/10-fig8910-th.jpg" align="right" alt="EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig. 8, 9, 10)" title="">
+</a>
+Figs. 8, 9 and 10 are diagrams showing the comparative
+efficiency of the three types of compressors at St.
+Fargeau&mdash;Fig. 10 being a diagram of the Riedler
+compressor&mdash;and indicate the gain derived from the
+intermediate cooling. The loss is shown to be only 12 per
+cent., as compared with a loss of 43 per cent. in a large
+part of the plant, and of 105 per cent. in the earlier
+compressors of the St. Gothard type. The table
+given herewith contains a summary of trials made
+by Professor Gutermuth, and are intended to show
+the comparative results of an extended trial with three
+kinds of compressors at St. Fargeau.</p>
+<br clear="all" />
+
+<pre>
+
+  PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
+
+--------------+-------+--------+------+-------+--------+--------+----------+
+              |       |        |      |       |        |        |          |
+              |Revolu-| Horse- |      |Amount |Quantity| Cubic  |          |
+Compressors.  | tions | Power  |Effic-|of Air | of Air |Feet of |Final Air |
+              |of Eng-|Absorbed|iency.|Passing| Passing|Air per |Pressure. |
+              |ine per|   by   |      |through| through| Horse- |          |
+              |Minute.|Compres-|      | Inlet | Valves | Power  |          |
+              |       | sors.  |      | Valves| per    | and per|          |
+              |       |        |      | each  | Hour.  |  Hour. |          |
+              |       |        |      |Revolu-|        |        |          |
+              |       |        |      | tion. |        |        |          |
+--------------+-------+--------+------+-------+--------+--------+----------+
+              |       |        |      | cubic |  cubic |        |lb. per   |
+1.            |       |        |      | feet  |  feet  |        |sq. in.   |
+<i>Sturgeon</i>      |       |        |      |       |        |        |          |
+<i>Compressor</i>    |  37   |   302  | .87  | 41.67 |  91,507| 261.3  | 90       |
+Diameter of   |  37   |   258  | .87  | 38.13 |  84,650| 276.1  | 90       |
+cylinder,     |       |        |      |       |        |        |          |
+23.62 in.     |       |        |      |       |        |        |          |
+and 21.66 in.;|       |        |      |       |        |        |          |
+stroke,       |       |        |      |       |        |        |          |
+48.63 in.     |       |        |      |       |        |        |          |
+              |       |        |      |       |        |        |          |
+2.            |       |        |      |       |        |        |          |
+<i>Cockerill</i>     | 40    |   337  | .83  | 46.61 | 111,864| 281.83 | 90       |
+<i>Compressor.</i>   | 45    |   353  | .83  | 46.61 | 125,844| 302.66 | 90       |
+Diameter of   | 40    |   342  | .88  | 49.43 | 118,632| 296.65 | 90       |
+cylinder,     | 46    |   377  | .85  | 48.02 | 132,534| 298.77 | 90       |
+25.98 in.;    | 38.67 |   324  | .89  | 50.14 | 116,434| 306.19 | 90       |
+stroke,       | 38.5  |   337  | .89  | 50.14 | 115,818| 294.18 | 90       |
+47.24 in.     | 38.6  |   329  | .91  | 50.84 | 117,740| 305.13 | 90       |
+              |       |        |      |       |        |        |          |
+              |       |        |      |       |        |        |          |
+3.            |       |        |      |       |        |        |          |
+<i>Riedler</i>       | 52    |   615  | .985 | 77.34 | 241,300| 353.50 | 90       |
+<i>Compressor.</i>   | 60    |   709  | .985 | 76.98 | 277,128| 353.50 | 90       |
+Diameter of   | 38    |   422  | .985 | 77.34 | 176,330| 376.12 | 90       |
+low-pressure  | 39    |   424  | .985 | 77.34 | 181,030| 384.60 | 90       |
+cylinder,     |       |        |      |       |        |        |          |
+42.91 in.;    |       |        |      |       |        |        |          |
+diameter of   |       |        |      |       |        |        |          |
+high-pressure |       |        |      |       |        |        |          |
+cylinder,     |       |        |      |       |        |        |          |
+26.38 in.;    |       |        |      |       |        |        |          |
+stroke,       |       |        |      |       |        |        |          |
+47.24 in.     |       |        |      |       |        |        |          |
+--------------+-------+--------+------+-------+--------+--------+----------+
+</pre>
+
+<p>The results thus obtained were so satisfactory that
+the designs were prepared for the great compressors to
+be operated at the new central station on the Quai de
+la Gare by the 2,000 horse power engines.</p>
+
+<p>The transmission of the compressed air through the
+mains is unavoidably attended with a certain percentage
+of loss, which, of course, increases with the length
+of the transmission, the presence of leakage at the
+joints, etc. Professor Riedler has devoted considerable
+time to the investigation of this source of waste,
+and we shall presently refer to the results he has
+recorded; in the first place, however, we propose to
+consider what he has to say on the subject of utilizing the
+air at the points of delivery, and the means employed
+for obtaining a relatively high efficiency of the motor.</p>
+
+<p>In the earliest stages of the Popp system in Paris it
+was recognized that no good results could be obtained
+if the air were allowed to expand direct into the motor;
+not only did the formation of ice due to the expansion
+of the air rapidly accumulate and choke the exhaust,
+but the percentage of useful work obtained,
+compared with that put into the air at the central station,
+was so small as to render commercial results
+hopeless. The practice of heating the air before admitting
+it to the motor is quite old, but until a few years
+ago it never seems to have been properly carried out;
+in several mining installations where this motive power
+had been long used, more or less imperfect attempts
+had been made to heat the air; in one instance only,
+recorded by Professor Riedler, was an efficient means
+employed. In this case a spray of boiling water was
+injected into the cylinder and mixed with the air at
+each stroke, with the result that a very marked economy
+was obtained.</p>
+
+<p>After a number of experiments, Mr. Popp arrived at
+the conclusion that the simplest mode of heating, if
+not the most efficient, was at all events the most suitable,
+as it was a matter of the first importance that subscribers
+should not be troubled with the charge of any
+apparatus involving complication or careful management;
+he therefore adopted a simple form of cast iron
+
+stove lined with fireclay, heated either by a gas jet or
+by a small coke fire. It was found that this apparatus,
+crude as it was, answered the desired purpose,
+until some better arrangement was perfected, and the
+type was accordingly adopted throughout the whole
+system. It was quite recognized that this method still
+left much to be desired, and the economy resulting
+from the use of an improved form was very marked.</p>
+
+<p>From a large number of trials very carefully carried
+out by Professor Gutermuth, it was found that
+more than 70 per cent. of the total number of calories
+in the fuel employed was absorbed by the air and
+transformed into useful work. Whether gas or coal
+be employed as the fuel, the amount required is so
+small as to be scarcely worth consideration; according
+to the experiments carried out, it does not exceed 0.09
+kilo. per horse power and per hour, but it is scarcely
+to be expected that in regular practice this quantity
+is not largely exceeded. Professor Weyrauch has also
+carefully investigated this part of the subject and fully
+confirms, if he, indeed, does not go beyond Professor
+Gutermuth. He claims that the efficiency of fuel consumed
+in this way is six times greater than when burnt
+under a boiler to generate steam. He goes so far as to
+assert that with a good method of heating the air, not
+only can all the losses due to the production and
+the transmission of the compressed air be made good,
+but also that it will actually contain more useful energy
+at the motor than was expended at the central
+station in compressing it.</p>
+
+<p>According to Professor Riedler, from 15 to 20 per
+cent. above the power at the central station can be
+obtained by means at the disposal of the power users,
+and it has been shown by experiment that by heating
+the air to 250 deg. Cent. an increased efficiency of 30
+per cent. can be obtained. Better results than those
+heretofore obtained may, therefore, be confidently expected
+with a more perfect and economical application
+of the fuel in heating the air, and a better means of
+regulation in admitting it to the motors. In his report
+Professor Riedler indicates a method by the use of
+which he considers considerable advantages may be
+secured. This is the heating the air in two stages instead
+of at one operation, and passing it through two
+motors, to the first of which the air is admitted heated
+only to a moderate extent; the exhaust from this motor
+then passes into a second heater and thence into
+the second motor. A series of experiments with this
+arrangement were recently carried out.</p>
+
+
+<p>The consumption of air per brake horse power was
+reduced from 812 cubic feet per hour, a favorable duty
+in the single motor, to 720, and in the best result to
+646 cubic feet with the two motors and double heaters.
+It should be added that these trials were carried out
+with steam engines but ill adapted for the purpose.
+It is to be regretted that the experiments of Professor
+Riedler could not have been conducted with more perfect
+appliances, but it must be borne in mind that the
+utilization of compressed air, especially as regards the
+motors, is still in a very imperfect stage, and that a
+great deal remains to be done before the maximum
+power available at the motor can be obtained. Investigations
+in this direction for a considerable time to
+come must be directed, therefore, toward improving
+the design and construction of the motors and the
+treatment of the air at the point of delivery into the
+engine.</p>
+
+<p>A large number of motors in use among the subscribers
+to the Compressed Air Company, of Paris, are rotary
+engines developing one horse power and less, and
+these in the early times of the industry were extravagant
+in their consumption, to a very high degree. To
+some extent this condition of things has been improved,
+chiefly by the addition of better regulating valves
+to control the air admission.</p>
+
+<p>As altered, the two horse power rotary motors, when
+employed as cold air engines, a method often desired
+in special industries, consume 1,059 cubic feet per hour
+and per indicated horse power; with a moderate degree
+of heating, say to 50 deg. Cent., this consumption
+falls to 847 cubic feet. The efficiency of this type of
+rotary motors with air heated to 50 deg. may now be
+assumed at 43 per cent., not a very economical result,
+it is true, and one that may be largely improved, yet it
+is evident that with such an efficiency the use of small
+motors in many industries becomes possible, while in
+cases where it is necessary to have a constant supply
+of cold air, economy ceases to be a matter of the first
+importance.</p>
+
+<p>Some useful results were obtained with compressed
+air used in crank engines; it is to be regretted that with
+this, also, apologies have to be made for the imperfect
+design and construction; they were old steam engines,
+some of those of two horse power losing from 25 to 30
+per cent. by their own friction; some of the others tried,
+however, were far better, a newer type losing only from
+8 to 10 per cent., while the 80 horse power referred to
+below showed an efficiency of 91 per cent. From these
+trials Prof. Riedler deduces&mdash;assuming 85 per cent. efficiency&mdash;a
+consumption of 611, 752, and 720 cubic feet
+per brake horse power. It is very evident from the
+foregoing that the Compressed Air Company, of Paris,
+will never do itself justice until as much thought and
+care has been devoted to the economical use of the motive
+power as has been expended in the means of producing
+it, and Professor Riedler's recent investigations
+should be especially useful in this respect. The question
+has indeed attracted the attention of more than
+one manufacturer, and reference is made to a particular
+type of small rotary motors which are being constructed
+by MM. Riedinger &amp; Co., and which is stated
+have given very excellent results. These engines were
+specially used for working sewing machines and developed
+on the brake an efficiency of 34.07 and 51.63
+foot pounds per second. Trials were made with a half
+horse power variable expansion Riedinger engine.</p>
+
+<pre>
+     TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
+ ______________________________________________________________
+                                               |       |
+  Number of trials.                            |   I.  |   II.
+ ______________________________________________|_______|_______
+                                               |       |
+ Initial air pressure.     lb. per square inch |    86 | 71.8
+      "      temperature.           deg. Cent. |   +12 |  +170
+ Ft. pounds per second  measured on the brake. | 51.63 | 34.07
+ Revolutions per minute.                       |   384 |  300
+ Consumption of air for one horse power per    |       |
+    hour.                                      | 1,377 |  988
+ ______________________________________________|_______|_______
+
+
+     TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
+ _____________________________________________________________________
+                                           |      |      |      |
+  Number of trials.                        |  I.  |  II. | III. |  IV.
+ __________________________________________|______|______|______|_____
+                                           |      |      |      |
+ Initial pressure of air.  lb. per sq. in. |   54 | 69.7 |   85 | 71.8
+      "  temperature of air.    deg. Cent. |  170 |  180 |  198 |    8
+ Final        "        "            "      |   25 |   20 |  ... |   25
+ Revolutions per minute.                   |  335 |  350 |  310 |  243
+ Foot pounds per second measured on        |      |      |      |
+    brake.                                 |  271 |  477 |  376 |  316
+ Consumption of air per horse power        |      |      |      |
+    and per hour.                          |  883 |  791 |  900 |1,148
+ __________________________________________|______|______|______|_____
+
+
+    TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
+ ______________________________________________________________
+                  |      |      |             |
+                  | Re-  | In-  |             | Consumption of
+                  | vo-  | di-  | Temperature |  air per horse
+                  | lu-  | ca-  |    of air.  |  power and per
+                  |tions | ted  |             |      hour.
+                  |      |      |_____________|________________
+                  | per  |horse |      |      |       |
+    Motor.        |      |      |Admis-| Ex-  |Nominal| Brake
+                  | min- |power.| sion.|haust.| horse | horse
+                  | ute. |      |      |      | power.| power.
+ _________________|______|______|______|______|_______|________
+                  |      |      |deg. C|deg. C|       |
+ Nominal 80 horse | 54.3 | 72.3 |  129 |  21  |  469  |  517
+ power single cy- | 54.3 | 72.3 |  152 |  29  |  437  |  475
+ linder Farcot    | 54.0 | 72.3 |  160 |  35  |  424  |  465
+ engine.          | 40   | 65.0 |  170 |  49  |  438  |  477
+ _________________|______|______|______|______|_______|______________
+</pre>
+
+<p>These motors, it may be assumed, represent the best
+practice that has been obtained up to the present time
+in the construction of compressed air motors; with the
+smallest of them, indicating about one-tenth of a horse
+power, the consumption of air, when admitted cold,
+was 1377 cubic feet and 988 cubic feet when the air was
+heated before admission. The half horse power engine
+consumed 1148 cubic feet of cold air, and of heated air
+791 cubic feet per horse power and per hour. It
+should be mentioned that these, the most valuable and
+suggestive of all the trials carried out by Professor
+Riedler, were conducted with the greatest care, two
+distinct modes of measuring the air supplied being
+followed on two occasions for each test; it may therefore
+be considered that the results given are absolutely
+correct. The trials were made with an old single cylinder
+
+Farcot engine, nominally of 80 horse power, but indicating
+over 72.3. With this engine the consumption of
+air varied from 465 to 517 cubic feet, the larger consumption
+being due to the lower temperature (129 deg.
+Cent.) to which the air was raised before admission; in
+the most economical result the temperature was 160
+deg. Cent. The volumes of air referred to are, of
+course, in all cases taken at atmospheric pressure.</p>
+
+<p>Among the important losses that have to be reckoned
+with in every system of distributing motive power
+from a central station&mdash;whether by steam or by electricity,
+water, or compressed air&mdash;losses must occur in
+the mains by which the power generated is transferred
+from the point of production to that of consumption.
+In the case we are now considering very careful tests
+were conducted in 1889 by Professor Kennedy, to whose
+report we have already referred. Since that time important
+changes have been made by the Compressed
+Air Company, at Paris, in the details of distribution,
+and on this account the later investigations of Professor
+Riedler on the losses due to this cause are of special
+interest.</p>
+
+<p>Before its admission into the mains a certain loss occurs
+at the St. Fargeau station, in the large reservoirs
+to which the air is delivered from the compressors. This
+question of preliminary storage was one that received
+considerable attention when the designs of the new station
+on the Quai de la Gare were being considered. It was
+intended to construct very large receivers in the basement
+of the station, and the foundations for these were
+even commenced. It was decided, however, that for
+the 10,000 horse power which is to form the first section
+of the new station, and for which the complete
+system of mains has already been laid down, storage
+reservoirs would be unnecessary, and a saving both in
+first cost and subsequent loss of air would be effected.
+The length of mains of 19.69 in. diameter is so considerable
+that they will contain at all times a sufficient
+reserve of air to prevent any irregularities in pressure
+at the motors.</p>
+
+<p>With reference to these mains it may be mentioned
+that, unlike the 11.81 in. conductors of the St. Fargeau
+system, of which 17 kilometers are laid in the Paris
+subways, the new mains are entirely laid in the streets,
+it having been found impossible to make room for these
+large pipes in the subways already crowded with telegraph
+and telephone wires, water mains, etc.</p>
+
+<p>Professor Riedler investigated the two causes of loss
+in the mains&mdash;leakage and resistance. It was superficially
+evident that the mains of the old system were
+so well laid, and the joints so well designed, that the loss
+from leakage was never a serious one. In order, however,
+to ascertain the amount accurately, a series of careful
+experiments were carried out by Professor Gutermuth
+with the 11.81 in. mains of the St. Fargeau
+system.</p>
+
+<p>These trials refer to the mains running from the St.</p>
+
+<pre>
+     EXPERIMENTS ON LEAKAGE IN MAINS.
+
+---------------------------------------------------------------------
+| |                 |         |               |             | L P A |
+| |                 |         | Air Pressure  |   Loss of   | o e i |
+| |                 |         |  in Mains.    |  Pressure.  | s r r |
+| |                 |         |---------------|-------------| s     |
+| |                 |         |       |       |      |      |   C D |
+| |System of Mains  | Length. |       |       |      |      | o e e |
+|N|    Tried.       |         |  At   |  At   |      |      | f n l |
+|u|                 |         |Begin- | End   |During| Per  |   t i |
+|m|                 |         |ning of|  of   |Trials|Hour. | A . v |
+|b|                 |         |Trials.|Trials.|      |      | i   e |
+|e|                 |         |       |       |      |      | r o r |
+|r|                 |         |       |       |      |      |   f e |
+| |                 |         |       |       |      |      |     d |
+--+-----------------+---------+-------+-------+------+------+-------|
+| |                 | yards.  | atm.  |  atm. |      |      |       |
+|1|Southern reseau  |         |       |       |      |      |       |
+| | to Place de la  |         |       |       |      |      |       |
+| | Concorde.       |  9,980  | 6.5   |  6.0  | 0.5  | 1.5  |  3    |
+|2| Total reseau    | 18,500  | 6.9   |  5.9  | 1.0  | 1.5  |  6.3  |
+|3|To Place de      |         |       |       |      |      |       |
+| | la Concorde     |  9,980  | 7.0   |  6.43 | 0.57 | 0.75 |  2.16 |
+|4|Total reseau     | 18,500  | 6.7   |  5.28 | 0.88 | 1.32 |  5.5  |
+|5|Northern reseau  |         |       |       |      |      |       |
+| | to Rue de Belle-|         |       |       |      |      |       |
+| | ville.          |  1,530  | 6.0   |  5.0  | 1.0  | 0.6  |  2.3  |
+|6|To the Rue des   |         |       |       |      |      |       |
+| | Pyrenees.       |    600  | 6.1   |  3.7  | 2.4  | 0.56 |  2.2  |
+---------------------------------------------------------------------
+</pre>
+
+<p>Fargeau station to the Place de la Concorde, a length
+of 9.142 kilometers; to the whole system of mains, 16.5
+kilometers; to the northern mains running from St.
+Fargeau to the Rue de Belleville, 1.4 kilometers; and
+from St. Fargeau to the Rue des Pyrenees, 6.5 kilometers.
+It will be seen from the figures given in the table
+that the actual loss is small, and it is stated that
+this is due chiefly to the elastic joint employed throughout
+the system, excepting in the Rue de Belleville,
+where rigid couplings are used, and continual trouble
+is experienced from loss by leakage. In all cases the
+losses given are the maximum, which only occur under
+the most unfavorable conditions.</p>
+
+<p>It was found, during the first, second, and fourth
+tests, that considerable leakage occurred between the
+St. Fargeau central station and the Rue de Belleville.
+During the trials two and four, an uncertain amount
+of loss occurred from the consumption of air required
+to work the pneumatic clocks, and also motors in the
+circuit, that could not be stopped. The tests two and
+four include all losses in the service pipes, as well as
+the mains.</p>
+
+<p>The production of compressed air at the central station
+is assumed at 30,000 cubic feet per hour (atmospheric
+pressure), and in all cases the loss in the
+mains is taken as a percentage of the total production.</p>
+
+<p>The losses due to resistance in the mains were also
+examined with great care, over independent sections,
+as well as through the complete <i>réseau</i>. During the
+early part of these trials, an unusual and excessive loss
+was recorded, the cause of which could not be at first
+ascertained. At intervals along these mains are placed
+a number of water reservoirs which receive the water
+injected into the mains; in addition to these the direct
+flow of the air is interrupted by numerous siphons, the
+stop valves to branches, etc. Investigation showed
+that the presence of these reservoirs created considerable
+resistance on account of an increased and subsequently
+reduced section. The exact loss from this
+cause was, therefore, carefully measured, as well as the
+losses existing in the mains not so interrupted. The
+results show that the loss by expansion at one reservoir,
+when the speed of the air flow was 23 ft. per
+second, was equal to 0.15 atmosphere; with a speed
+of 29 ft. 6 in. per second, it amounted to 0.2 atmosphere.</p>
+
+<p>Therefore, the presence of five such reservoirs would
+cause a loss in pressure equal to one atmosphere. This
+very undesirable arrangement is not repeated in the
+new system, the sumphs being connected in such a way
+as not to modify the section of the tube, nor consequently
+the pressure of the air. The presence of the
+siphons and stop valves did not seem to affect the
+pressure to any measurable extent. The following
+table contains a list of the more important mains tested,
+and it may be mentioned that the resistance, due
+to the reservoirs, was at first partially included. The
+trials were carried out while the mains were not being
+drawn upon by subscribers. </p>
+
+<pre>
+-----------------------------------------------------------------------
+                                                   |            |
+Section of Mains Tested.                           |  Length.   |No. of
+                                                   |            |Tests.
+                                                   |            |
+---------------------------------------------------+------------+------
+                                                   |  yards.    |
+From the central station to the end of reseau and  |            |
+  back to central station by return circuit        |  18,100    |   7
+From the central station to the Rue Fontaine au    |\ 14,600    |/  3
+  Roi                                              |/  9,900    |\  4
+From the central station to the Rue de la          |            |
+  Charonne                                         |   9,490    |   5
+From the Rue de la Charonne to Fontaine au         |            |
+  Roi                                              |   4,770    |   3
+From the central station to the Avenue de la       |            |
+  Republique                                       |   1,860    |   8
+Various trials on different lengths of mains       |770 to 8,000|  11
+-----------------------------------------------------------------------
+</pre>
+
+<p>Over the whole system of 16.5 kilometers, which was
+also tested when no air was being taken off, there were
+four reservoirs of considerable size, and which offered
+a large resistance with a corresponding loss of pressure;
+on the line there were also 23 siphons and 42 stop
+valves.</p>
+
+<p>These trials were repeated several times to secure
+accuracy, and the speed of the air was brought to 49
+ft. a second. The results obtained in one of these trials
+may be taken as an example. The main between the
+Rue St. Fargeau and the Fontaine au Roi, on which
+there are no collecting reservoirs, but three siphons
+and eight stop valves, gave, with an average speed of
+21 ft. 3 in., a loss in pressure of 0.05 atmosphere for each
+kilometer of main.</p>
+
+<p>From these experiments it would appear that, assuming
+a speed of 21 ft. per second, a loss in pressure
+of one atmosphere would correspond to a distance of
+20 kilometers; that is to say, a central station could extend
+its mains on all sides with a radius of 20 kilometers,
+and the motors at the ends of the lines would receive
+the air at a pressure 15 lb. less than at the central
+station. Professor Riedler states that as an actually
+measured result, the velocity of the air through the
+mains of the St. Fargeau system is 19 ft. 8 in. per
+second, and that the loss in pressure per kilometer is
+0.07 atmosphere. From this it follows that including
+the resistances due to the four reservoirs, and other obstructions
+actually existing, an allowance of one atmosphere
+loss on a 14 kilometer radius is ample. By
+increasing the initial pressure of the air, much better
+results can be obtained, and future attention in practice
+should be devoted to this point. The amount of
+work required to compress air does not increase in the
+same ratio as the pressure, and for this reason considerable
+economy can be effected at the first stage,
+and the loss in the mains will be reduced.</p>
+
+<p>Passing to another point of the same subject, Professor
+Riedler considers the best dimensions that should
+be given to the mains. Resistance decreases with an
+increase in the diameter of these and in direct ratio to
+their diameter; for this reason&mdash;still assuming a pressure
+corresponding to a velocity of 20 ft. per second&mdash;with
+a fall of one atmosphere, a length of 40 kilometers
+could be succesfully worked.</p>
+
+<p>The mains of the new <i>réseau</i> for the Quai de la Gare
+station are 19.69 in. in diameter; they are built up of
+steel plates riveted, and this Professor Riedler considers
+to have been a serious error on account of the
+extra resistance offered by the large number of rivet
+heads.</p>
+
+<p>The following may be taken as a brief summary
+of Professor Riedler's conclusions: Recent improvements
+in central station practice have resulted in an
+increased efficiency of about 30 per cent. in the compressors,
+but this benefit can only be realized when the
+new station is in operation. That the small and very
+imperfect air engines in use on the system give an
+efficiency of 50 per cent., while with ordinary
+steam engines driven by air an efficiency of 80 per cent.
+can be reached with a very small expenditure of fuel
+for heating the air before admitting it into the motor.
+That special attention should be given to the improvement
+of air engines, and that with increased initial
+pressures at the central station the distance of the
+transmission can be very considerably augmented.
+Finally, Professor Riedler claims that power can be
+transmitted by compressed air more conveniently and
+more economically than by any other means.</p>
+
+<hr />
+
+[Continued from SUPPLEMENT, No. 802, page 12810.]
+
+<a name="me-1"></a><h2>THE BUILDERS OF THE STEAM ENGINE&mdash;THE FOUNDERS OF MODERN INDUSTRIES
+AND NATIONS.<a name="FNanchor_1a"></a><a href="#Footnote_1a"><sup>1</sup></a></h2>
+
+<h3>By Dr. R.H. THURSTON, Director of Sibley College,
+Cornell University.</h3>
+
+<p>Papin, Worcester, Savery, were the authors of the
+period of application of the power of steam to useful
+work in our later days. The world was, in their time,
+just waking into a new life under the stimulus of a new
+freedom that, from the time of Shakespeare, of Newton,
+and of Gilbert, the physicist, has steadily become
+wider, higher, and more fruitful year by year. All the
+modern sciences and all the modern arts had their
+reawakening with the seventeenth century. Every
+aspect of freedom for humanity came into view in those
+days of a new birth. Both the possibility of the introduction
+of new sciences and of new arts and the power
+of utilizing all new intellectual and physical forces
+came together. The steam engine could not earlier
+have taken form, and, taking form, it could not have
+promoted the advance of civilization in the earlier
+centuries. The invention becoming possible of development
+and application, the promotion of the arts and
+of all forms of human activity became a possible consequence
+of its final successful introduction into the rude
+arts that it was to so effectively promote and improve.</p>
+
+<p>But the work of these inventors was in itself but
+little more important than that of the Greek inventor of
+the steam ælopile, for each brought forward a machine
+which was, from a business point of view, utterly
+impracticable, and which, in each case, only served to
+show that a better device might prove useful and lead
+the way to its introduction. The merit of the inventors
+of the eighteenth century was that they were <i>able</i> to
+lead the way, to point out the path to success, to furnish
+evidence of the value of the coming, crowning
+invention. The "fire engines," as they were then
+called, of these now famous men were merely contrivances
+by the use of which the pressure of confined
+steam of high tension could be brought to act on the
+surface of a mass of confined water, forcing it downward
+into pipes through which it was led off and
+upward to a higher level; and thus a mine could be
+drained, ineffectively and expensively to be sure, but
+vastly more satisfactorily than by the animal power
+of the time. The machine of Savery was the best of
+all; but that was only a somewhat improved and manageable
+rearrangement of the engines of Papin and
+Worcester. And, after all, Papin, the greatest man of
+science perhaps of his time, died in poverty; Worcester
+languished in prison his whole life, and the later
+efforts of his widow brought nothing by way of a
+return for his invention; nor did either they or their
+successor, Morland, make the introduction of the
+engine either general or remunerative.</p>
+
+<p>Savery, coming on the stage at more nearly the right
+time to seize upon an opportunity, gained more than
+either of his predecessors; but we have no evidence
+that he ever acquired any large compensation or met
+with any remarkable business success in the introduction
+of the rude engine which bore his name; nor did
+Desaguliers, the great philosopher, or even Smeaton, the
+great engineer, of the later years of that century, make
+any great success of it. It was reserved for Watt to
+reap the harvest. But, though he so effectively reaped
+where his predecessors had sown, Watt is not the
+greatest of the inventors of the steam engine, if we
+rate his standing by the magnitude of the improvement
+which marked his reconstruction of the engine.</p>
+
+<p>It was NEWCOMEN who made the modern steam
+engine.</p>
+
+<p>When Newcomen came forward the labors of Worcester
+in Great Britain had sufficed to attract the attention
+of all intelligent men to the character of the
+problem to be solved, and to convince them of its
+importance and promise. The work of Savery had
+shown the practicability of the solution of the problem,
+both in mechanics and finance. He succeeded,
+though under great disadvantages and comparatively
+inefficiently. Once the task had been performed,
+though ever so rudely, the rest came easily and promptly.
+The defects of the Savery system were at once
+recognized; its great wastes of heat and of steam were
+noted, and the fact that they were inherent in the system
+itself was perceived. A complete change of type
+of machine was obviously requisite; it was this which
+constituted the greatest invention in the whole history
+of the steam engine, from Hero's time to our own; and
+to Newcomen we owe more than to any other man who
+ever lived, the value of the invention itself being considered,
+and the importance of the services of its introducer
+being left out of consideration. No such
+complete and vital improvement and modification of
+the machine has ever been effected by any other man,
+Watt and Corliss not excepted. Newcomen and his
+comrade Calley&mdash;we do not know how the honors
+should be divided&mdash;produced the modern steam engine.
+Its predecessor, the Savery engine, had been a mere
+steam "squirt." Newcomen constructed an engine.
+Savery built a simple combination of cylindrical or
+ellipsoidal vessels which wastefully and at once performed
+all the several offices of engine, pump, condenser,
+and boiler; Newcomen divided the several
+elements among as many parts, each especially adapted
+to the performance of its task in the most effective
+manner&mdash;the condenser excepted; for that was Watt's
+principal invention&mdash;and thus produced the first steam
+engine in the modern sense of that term.</p>
+
+<p>It was Newcomen, not Watt, who gave us the train
+of mechanism that we now call the steam engine. It
+is to Newcomen, rather than Watt, that we owe the
+highest honors as an inventor in this series of the
+most important of all the products of the inventive
+genius of mankind. Newcomen brought into existence
+a new, the modern, type of engine, and effected the
+greatest revolution that has been recorded in the history
+of the arts. Without Newcomen, there might
+have been no Watt; without Watt, there very possibly
+may not even yet have been brought into existence
+that giant of our time, whose mighty powers are
+employed more effectively than ever those of Aladdin's
+genii, in building palaces, in transporting men and
+material, in doing the work of the whole world; promoting
+the welfare of the race, in a single century,
+more than had all the forces of matter and mind
+together in the whole previous history of the world.
+Newcomen laid down a foundation beneath our whole
+economic system, out of sight, almost, but the essential
+base, nevertheless, on which Watt and his successors
+have carried up the great superstructure which seems
+to us to-day so imposing; which is so tremendous in
+magnitude, importance, and result. If to any one man
+could be assigned the credit, it is Newcomen who is to
+be considered the inventor of the steam engine.</p>
+
+<p>James Watt, indisputably the great inventor that he
+was, found the steam engine ready to his hand, applied
+himself to its improvement, and made it substantially
+what it is to-day. His most important work, the most
+unique service performed by him, was, however, that
+of its adaptation and introduction to do the work of
+the world. James Watt was the inaugurator of the
+era of refinement of the machine already invented, and
+the greatest of its builders and distributors. His inventions
+were all directed to the improvement of its
+details, and his labors to its introduction and its application
+to the myriad tasks awaiting it. By the hands
+of Watt it was made to pump water, to spin, to weave,
+to drive every mill; and he it was who gave it the
+form demanded by Stephenson, by Fulton, by the
+whole industrial world, for use on railway and
+steamboat, and in mill and factory, throughout the
+civilized countries of the globe. It was this great mechanic
+
+who showed how it might be made to do its
+work with least expense, with highest efficiency, with
+greatest regularity, with utmost concentration of
+power.</p>
+
+<p>The grand secret of his success was historical and
+economic, as much as scientific and mechanical. He
+brought out his inventions just when the world was
+economically and historically ready for them. The age
+of authority was past, that of freedom was come; the
+period of political and ecclesiastical tyranny was gone
+by, and that of the spontaneous development of man
+was arrived. The great invention was offered to a
+world ready and needing it, and, more than all, competent,
+for the first time in history, to make and use
+it.</p>
+
+<p>James Watt was himself a product of the modern
+scientific spirit. He was a man so constituted mentally
+that he could apply scientific methods to problems
+which his logical and clairvoyant mind could readily
+and exactly formulate the instant he was led to their
+consideration in the natural course of his progress. He
+was the ideal great inventor and mechanic. With
+inventive genius he combined strong common sense&mdash;not
+always a quality distinguishing the inventor&mdash;clear
+perception, breadth of view, and scientific method
+and spirit in the treatment of every question. His
+natural talent was re-enforced by an experience and an
+environment which led him to develop these ways and
+this mental habit. His trade was that of an instrument
+maker, his position was that of custodian and repairer
+of the apparatus of Glasgow University. He had for
+his daily companions and stimulus the great men and
+ozonized atmosphere of that famous institution. He
+kept pace with advancing science, and was imbued,
+both naturally and through contact with its promoters,
+with that ambition and those aspirations which are
+the life element of all progress, whether scientific or
+other. He was aware of the nature of the problems
+seeking solution at the time, and familiar with the
+state of his own art and that of the great mechanicians
+about him. Everything was favorable to his progress,
+so soon as he should be given an opportunity to take a
+step in advance and to come into sight at the front.
+The man and the time were both ready, and all conditions,
+internal and external, social and personal, were
+favorable to his development.</p>
+
+<p>The invention upon which Watt was to improve was
+at his hand. A word in regard to its status at the
+moment will throw some light upon that of Watt and
+his creation. Newcomen had, as we have seen, produced
+the modern type of steam engine as an original
+and wholly novel invention. But this machine, marvelous
+as an advance upon pre-existing forms of the
+steam engine, was still, as seen in the light of recent
+knowledge and experience, exceedingly defective. The
+purpose of a steam engine is to convert into usefully
+applicable power the hidden energy of fuel, stored
+ages ago in the earth, by transformation, through the
+action of vegetation, from the original form, the heat
+of the sun, into an available form for reconversion,
+through thermodynamic operations. In this process
+of reconversion, whatever the nature of the machine
+used in the operation, there are invariably wastes,
+both of heat required for conversion into power and of
+the power thus produced. That machine which effects
+the most complete transmutation of the heat supplied
+it into mechanical power, which wastes the least amount
+of heat supplied and of power produced, is the best
+engine, and constitutes an advance over every other.</p>
+
+<p>It was this reduction of wastes that made the Newcomen
+engine so much superior to that of Savery. The
+latter was by far the simpler and less costly construction;
+but its enormous losses, both of heat and of power,
+mainly the former, however, made it an extravagant
+expenditure of money to buy and use it. The Newcomen
+engine, costly and cumbrous, comparatively,
+nevertheless wasted so much less heat and steam and
+fuel that no one could afford to buy the cheaper machine.
+Before considering what Watt accomplished, we
+may find it profitable to examine into the nature of
+the wastes which characterized this later and better
+machine on which he effected his improvements.</p>
+
+<p>The Newcomen engine consisted of a steam boiler, a
+steam cylinder, a beam and a set of pumps. By making
+the boiler do its work separately, the engine acting
+independently, and the pumps as a detached portion
+of the mechanism, this inventor had reduced to an
+enormous extent those wastes of heat and of steam and
+of fuel which were unavoidable in the older machines
+in which all these parts were represented by a single
+vessel, or by two at most, in each element. In the
+Savery engine, the steam entering first heated up the
+interior of the working vessel to its own temperature,
+and held it at that temperature in spite of the cooling
+influence of the water present. This consumed large
+quantities of heat. It then was compelled to surrender
+probably much greater quantities still to the water
+itself, coming in direct contact as it did with its surface.
+If the water was agitated, either by the currents
+produced during its ingress or by the impact of the
+steam entering the vessel, this heating action penetrated
+to considerable depths and perhaps even warmed
+the whole mass very far above its initial temperature.
+This constituted another and a very serious loss. Then,
+again, as the water was gradually driven out of the
+containing vessel by the steam pressing on its surface,
+new portions of the vessel and new masses of water
+were continually brought in contact with the hot steam,
+taking its full temperature, and thus, often, probably,
+finally heating the whole mass of the forcing vessel,
+and a large proportion of the water as well, up to the
+temperature, approximately at least, of the steam itself.
+Thus in many instances, if not always, vastly more heat
+and steam were wasted, in this undesirable heating
+of water and forcing vessel, than were usefully employed
+in the legitimate work of raising the water to a
+higher level. In fact, in some cases in which these
+quantities were measured, the wastes were one hundred
+times as much as the work done. One per cent.
+of the heat supplied did the work; while ninety-nine
+per cent. was thrown away. One dollar or one
+shilling expended for fuel to do the work was accompanied
+by an expenditure of ninety-nine dollars or
+shillings thrown away, because of the imperfections of
+the system and machine. The whole history of the
+development of the steam engine has been one of
+gradual reduction of these wastes; until to-day, our
+best engines only compel us to spend five dollars for
+wastes to each dollar paid out for useful work. A
+business man would think that amply extravagant,
+however, and the man of science is continually seeking
+methods of evading these losses, a large proportion of
+which are now apparently unavoidable in heat engines,
+by finding some new system of heat and energy transformation.</p>
+
+<p>Watt was the instrument maker and repairer at Glasgow
+University in the year 1763. His companions were,
+among others, the professors of natural philosophy and
+of mathematics in the university. Their conversation
+and their frequent presentation of practical and scientific
+questions and problems stimulated his naturally
+inquiring and inventive mind to the pursuit of a thousand
+interesting and promising schemes for the improvement
+of existing methods and machinery. Dr.
+Robison, then a student, suggested the invention of a
+steam carriage for use on common roads, and the young
+mechanician at once began experiments that, resulting
+in nothing at the time, were nevertheless continued, in
+one or another form, until all modern applications of
+steam came into view. Dr. Black taught Watt chemistry,
+then a newly constructed science, and led him on
+to the discovery, finally made by them independently,
+of the fact and the magnitude of the latent heat of
+steam; the discovery coming of a series of scientifically
+planned and accurately conducted investigations, such
+as the man of science of to-day would deem creditable.
+The treatises of Desaguliers and others on physics gave
+Watt a knowledge of that domain of natural phenomena
+which stood him in good stead later, when he
+attempted to apply its principles to the reduction of
+the wastes of the steam engine.</p>
+
+<p>It was while at Glasgow University, working under
+such influences and in such an atmosphere of intellectual
+activity, that the accident of the Newcomen
+model engine needing repair brought to the mind of
+Watt the opportunity which, availed of at once, made
+him famous and gave the world its greatest aid, its
+most powerful servant. The observing mind of the
+great mechanic immediately noted its defects, sought
+their causes, found their remedy. He discovered, at
+once, that the quantity of steam entering the cylinder
+of the little engine has four times the volume of the
+cylinder receiving it: in other words, three-fourths of
+that steam must be condensed immediately on entrance.
+This meant, evidently, that only one-fourth
+of the steam supplied was utilized, and even then inefficiently,
+in doing its work. The reason of this was as
+easily seen, immediately the fact was revealed. As Watt
+himself expressed it, the causes of this loss, causes
+which would obviously be exaggerated in a small
+engine, were: "First, the dissipation of heat by the
+cylinder itself, which was of brass and both a good
+conductor and a good radiator. Secondly, the loss of
+heat consequent upon the necessity of cooling down the
+cylinder at every stroke in producing the vacuum.
+Thirdly, the loss of power due to the pressure of vapor
+beneath the piston, which was a consequence of the
+imperfect method of condensation." This much determined,
+the next step looked toward the confirmation
+of his conclusions and the remedy of the defects.</p>
+
+<p>To meet the first difficulty he made a cylinder of
+wood, soaked in oil and baked, a non-conducting and
+non-radiating material. Then he was able to determine
+with some accuracy the quantities of steam and
+injection water used in the engine; and a comparison
+with the original cylinder and its operation showed
+that not only four times the quantity of steam, but also
+four times the amount of injection water was used as
+was necessary, assuming wastes checked. Further
+scientific research on the part of Watt gave him measures
+of specific heats of the metals and of wood, the
+specific volumes of steam at various working pressures,
+the evaporative efficiency of boilers, the pressures and
+temperatures of steam in the boiler under specified
+conditions, the quantities of steam and of water required
+for the operation of his little condensing
+engine.</p>
+
+<p>Then came his enunciation of the grand principle of
+economy in the construction and operation of the steam
+engine: "Keep the cylinder as hot as the steam which
+enters it," as he expressed it. This was Watt's guiding
+principle, as it has been that of all his successors in the
+improvement of the economic performance of the steam
+engine and of all other heat engines. The great source
+of waste is the dispersion of heat, uselessly, which
+should be applied to the production of work by its
+transformation, thermodynamically, into the latter
+form of energy. The second form of waste is that of
+power thus produced in the unprofitable work of moving
+the parts of the engine itself; and the third is that
+of heat by transfer, without transformation, by conduction
+and radiation to surrounding bodies. In
+modern engines, the latter is but three or five per cent.,
+in the best cases; the second waste constitutes perhaps
+ten per cent.; while the first of these losses
+amounts very usually to seventy per cent., of which
+last one-third or one-fourth is of the kind discovered
+by Watt, the rest being the thermodynamic waste incident
+to all known methods of operation of heat
+engines, and apparently unavoidable. In our very
+best and largest engines, the waste found by Watt to
+constitute three fourths of all heat supplied has been
+brought down to ten per cent., a fact which well exemplifies
+the advances made since his time of apprenticeship
+by himself and his successors of this nineteenth
+century. The steam engine of to-day, in its most successful
+operation, gives us twenty-five times as much
+power from a pound of coal as did the engine that the
+great inventor sought to improve: this is the magnificent
+fruit of that one discovery of James Watt,
+and of application of the simple principle which he so
+concisely and clearly stated.</p>
+
+<p>The method adopted by Watt to secure a remedy,
+so far as practicable, of this defect of the older machine
+was as simple and as perfect as was the principle
+which it embodied. He first removed from the cylinder
+the prime source of its wastes; providing a separate
+condenser, and thus avoiding the repeated chilling
+of its surfaces by the cold water used in condensing
+the steam at exhaust, and also permitting its strokes
+to be made with far greater frequency, thus giving less
+time for cooling by the influence of the remaining
+vapors after condensation. He next went still further,
+and provided the cylinder with a closed top, keeping
+out the air, and a "jacket" of hot boiler steam to
+<i>keep</i> it as hot as the steam which entered it. These
+were the two great improvements which converted the
+first real steam engine into an economical form of heat
+engine and essentially finished the work so grandly begun
+by Newcomen and Calley. These changes gave
+
+us the modern steam engine; and these are Watt's
+first and greatest, but by no means only, contributions
+to the production of the modern world with all its
+comforts, its luxuries and its opportunities for material,
+intellectual and moral advancement of individual
+and of race. His work was to this extent complete in
+1765.</p>
+
+<p>But Watt did not stop here. There still remained
+for him the no less important and the, in some senses,
+still more imposing, work of finding employment for
+the new servant of mankind and of setting it at its
+work of giving the human arm a thousand times
+greater strength, to the mind of man uncounted opportunities
+to promote the advancement of knowledge,
+of civilization, of every good of the race. His was still
+the task of adapting the new machine to all the purposes
+of modern industry. It had been hitherto confined
+to the task of raising water from the depths of
+the mine; it was now to be harnessed to the railway
+train; to be made to drive the machinery of the mill,
+to apply its marvelous power to the impulsion of the
+river boat and ocean steamer; to furnish energy,
+through endless systems of transfer and use, to every
+kind of work that man could devise and should invent.
+All this meant the giving of the machine forms as various
+as the purposes to which it was to be devoted. It
+had previously only raised and depressed a rod; it must
+now turn a shaft. It had then only operated a pump;
+it must now turn a mill, grind our grain, spin our
+threads, weave our cloths, drive our shops and factories,
+supply the powerful blast of the iron furnace. It
+must be made to move with the utmost conceivable
+regularity, and must, with all this, do its work in the
+development of the hidden energy of the fuel, with
+the greatest possible economy, through the expansion
+of its steam. All this was achieved by James Watt.</p>
+
+<p>The invention of the double-acting engine, in which
+the impulsion of the steam is felt both in driving the
+piston forward and in forcing it backward, both upward
+and downward, the application of its force
+through crank and fly wheel, the creation of an automatic
+system of governing its speed, and the discovery
+of the economy due to its complete expansion,
+were all improvements of the first magnitude, and of
+the greatest practical importance; and all these were
+in rapid succession brought into existence by the creative
+mind that had apparently been brought into the
+world for the express purpose of giving to the hand of
+man this mighty agent, to perfect the mightiest power
+that mind of man has yet conceived.</p>
+
+<p>But to do the rest required more than inventive
+genius and mechanical skill. It demanded capital and
+the stored energy of labor and genius in other fields,
+directed by the mind of a great "captain of industry."
+This came to Watt through Matthew Boulton, a manufacturer
+of Birmingham, whose father and ancestors
+had gradually and toilsomely, as always, accumulated
+the property needed for the prosecution of a great
+business. The combination of genius and capital is
+always an essential to success in such cases; and
+good fortune, a Providence, we may well say, brought
+together the genius and the capitalist to do their work,
+hand in hand, of providing the world with the steam
+engine. Hand in hand they worked, and all the world
+to-day, and the race throughout its future life, must
+testify gratitude for the inexpressible obligations under
+which these two men have placed them, doing the
+work of the world.</p>
+
+<p>Boulton &amp; Watt, the capitalist with the inventor,
+gave the world the steam engine, finally, in such form
+and in such numbers that its permanent establishment
+as the servant of man was insured. The capitalist was
+as essential an element of success as was the inventor,
+and, in this instance, as in a thousand others, the race
+is indebted to that much-abused friend of the race, the
+capitalist, for much that it enjoys of all that it desires.
+The industry and patience, the skill and the wisdom
+required for the accumulation of this energy stored for
+future use in great enterprises is as important, as essential,
+as inventive power or any other form of genius.
+Talent and genius must always aid each other. This
+firm was established in 1764 and its main resources,
+aside from the bank account, were Watt's patent,
+about expiring, and Watt's genius, and Boulton's talent
+as a man of business. The patent was extended
+for twenty-four years, the new inventions of Watt, now
+beginning to pour from his prolific brain in a wonderful
+stream, were also patented, and the whole works
+were soon employed upon the construction of engines
+for which numerous orders soon began to pour in upon
+the now prosperous builders. The patent law established
+Boulton and Watt and the firm paid back the
+nation with handsome usury, giving it unimaginable
+profits indirectly through its control of the work of the
+world and large profits directly through the business
+brought them from all parts of the then civilized globe.
+There has never, in the history of the world, been a
+more impressive illustration of the value to a nation of
+that generous public policy, that simply just legislation,
+which gives to the man of brain control of the
+products of his mind. For a hundred years, Great
+Britain has, largely through her encouragement of the
+inventor and her protection of his mental property by
+securing the fruits of his labors, in fair portion, to him,
+gained the power of dictating to the world and has
+gained an advance that cannot be measured. Watt
+and Arkwright and Stephenson and Crompton and their
+ilk, protected by their government and its patent laws,
+made their country the peaceful conqueror of the
+world. The story of the work of the inventor is a
+poem of mighty meaning and of wonderful deeds. The
+inventor proved himself a mightier magician than
+ever the world had seen.</p>
+
+<p class="ind">
+"A creature he called to wait on his will,<br />
+Half iron, half vapor&mdash;a dread to behold;<br />
+Which evermore panted, and evermore rolled,<br />
+And uttered his words a millionfold."</p>
+
+
+<p>Such was the outcome of this grand modern "trust,"
+a combination of the wisest legislation, the most brilliant
+invention, and the most wisely applied capital.
+There are "trusts" of which the outcome is most beneficent.</p>
+
+<p>Since the days of Watt, the improvement of the
+steam engine and the work of inventors has been confined
+to matters of detail. All the fundamental principles
+were developed by Watt and his predecessors and
+contemporaries and it only was left to his successors to
+find the best ways of carrying them into effect. But
+these matters of detail have been found to involve opportunities
+
+to make enormous strides in the direction
+of securing improved efficiency of the machine. The
+further application of the principle which led Watt to
+his greatest inventions; of the principle, keep the
+cylinder as hot as the steam which enters it, of that
+which he enunciated relative to the advantage of expanding
+steam, and of that affecting the regulation of
+the machine; have reduced the costs of steam and of
+fuel to a small fraction of their earlier magnitude. One
+ton of engine to-day does the work of eight or ten in
+the time of Watt: one pound of fuel or of steam gives
+to-day ten times the power then obtained from it. A
+steamship now crosses the Atlantic in one-eighth the
+time required by the famous "liner" of the "Black
+Ball Line." The wastes of the engine have been
+brought down from above eighty per cent. to eight;
+and a half-ounce of fuel on board ship will now transport
+a ton of cargo over a mile of ocean.</p>
+
+<p>FREDERICK E. SICKELS gave us the first practicable
+form of expansion gear in 1841; GEORGE H. CORLISS
+gave a new type of engine of marvelous perfection and
+economy in 1849; Noble T. Green, Wm. Wright and
+many less well known but no less meritorious inventors
+have since done their part in the transformation
+of the old engine of Watt into the modern wonder of
+concentrated and economical power, and marvel of
+accurate and beautiful design and workmanship. The
+"trip cut-off," with reduced clearances, increased boiler
+pressure, higher rates of expansion, accelerated speeds
+of engine, better construction in all respects, as well as
+improved design, have enabled us to avail ourselves to
+the utmost of the principles of Watt, and our mills, our
+railways, our steamers and our fields, even, have
+gained almost as extraordinarily by these advances,
+since the days of the great inventor, as through his
+immediate labors.</p>
+
+<p>With the introduction of the new form of older energy,
+electricity, with the reduction of the lightning
+into thraldom, has now come a new impulse affecting
+all the industries. Through its mysterious, its still unknown
+action, steam now reaches out far from its own
+place, driving the electric car along miles of rail; giving
+light throughout all the country about it, turning
+night into day, and repressing crime while encouraging
+legitimate labor, reaching into distant chambers and
+every little workshop, to offer its powerful aid in all the
+distributed work of cities. Without the steam engine
+there would be little work available for electricity, but
+the appearance of this, the latest and most useful
+handmaid of steam, has given the engine work to do
+in an uncounted number of new fields, has called in the
+inventor once more to adapt steam to its new work.
+The "high-speed engine" is the latest form of the
+universal helper. And such has been the readiness
+and the intelligence of the contemporary inventor that
+we now have engines capable of turning their shafts
+three hundred rotations a minute and without a perceptible
+variation of velocity, whatever the change of
+load or the suddenness with which it is varied. In the
+days of Watt a fluctuation of five per cent. in speed
+was thought wonderfully small; in those of Corliss, the
+variation was restricted to two per cent. and we wondered
+at this unanticipated success. To-day, thanks
+to Porter and Allen, to Hartnell, to Hoadley, to Sims,
+to Thomson, to Sweet, to Ide, and to Ball, we have
+seen the speed fluctuation restricted to even less than
+one per cent. of its normal average.</p>
+
+<p>The inventors of the steam engine are, through their
+representatives of to-day, according to the statisticians,
+doing the equivalent of twelve times the work of a
+horse, for every man, woman and child on the globe.
+We have not less, probably, than a half million of miles
+of railway, transporting something over 150,000,000,000
+of tons a mile a year. A horse is reckoned to haul a
+ton weight about six and a half miles, day by day, by
+the year together. In the United States, it is reckoned
+that the steam engine, on the railways alone, hauls a
+thousand tons one mile, for every inhabitant of the
+country, every year, or, if it is preferred to so state
+it, a ton a thousand miles. This is the way in which
+the East and the West are, by the inventors of the
+steam engine, enabled to help each other. This costs
+about $10 each individual; it would require some 25
+millions of horses to do the work, and would cost about
+$1,000 a family, which is more than twice the average
+family earnings.</p>
+
+<p>Dr. Strong, in that remarkable book, "Our Country,"
+says: "One man, by the aid of steam, is able to do the
+work which required two hundred and fifty men at the
+beginning of the century. The machinery of Massachusetts
+alone represents the labor of more than 100,000,000
+men, as if one-half of all the workmen of the
+globe had engaged in her service." And again: "Some
+thirty years ago, the power of machinery in the mills
+of Great Britain was estimated to be equal to 600,000,000
+men, or more than all the adults, male and female,
+of all mankind." Mr. Gladstone estimated that the
+aggregation of wealth on the globe during the whole
+period from the birth of Christ to that of Watt was
+equaled by the production in twenty years, at the middle
+of this century, with the aid of machinery driven
+by the fruit of the brain of the inventors of the steam
+engine. We may probably now safely estimate the
+former quantity as rivaled in less than five years,
+while, since the birth of Watt and his engine, and the
+production of the spinning mule, the power loom, the
+cotton gin and our own patent system and its marvelous
+mechanism, all events of a century ago, we may
+estimate that they have, together, accomplished more
+in this period which we now celebrate than could have
+been done in a millenium of milleniums without these
+now subjected genii. But the power behind all these
+curious inventions and their work is that of steam.
+The steam engine even supplies power to the telegraph
+and transports words and thought as well as cotton
+bales and coal.</p>
+
+<p>And now what has this combination of legislation
+for private protection and public good, of a genius
+producing great inventions, and of the accumulated
+capital of earlier years, brought about?</p>
+
+<p>It has given us the best fruits of science in permanent
+possession. The study of science invariably aids,
+in a thousand ways, the progress of mankind. It gives
+us new conceptions of nature and of the possibilities of
+art; it promotes right ways of work and of study; it
+teaches the inventor and the discoverer how most surely
+and promptly to gain their several ends, it gives the
+world the results of all acquired knowledge in concrete
+form. This one instance which we are now especially
+interested in contemplating has performed more wonderful
+miracles than ever Aladdin's genii attempted.
+One man, with a steam engine at his hand, turns the
+wheels of a great mill, drives forty thousand spindles,
+applies a thousand horse power to daily work in the
+spinning of threads, the weaving of cloth, the impulsion
+of a steamboat, or the drawing of great masses of
+hot iron into finest wire. This puny creature, his
+mind in his finger tips, exerts the power of ten thousand
+men, working with muscle alone, and, aided by a
+handful of women, boys and girls, clothes a city. A
+half dozen men in the engine room of an ocean steamer,
+with a hundred strong laborers in the boiler room
+and on deck, transports colonies and makes new nations,
+brings separated peoples together, unites countries on
+opposite sides of the globe, brings about easy exchanges
+between pole and equator. One man on the
+footboard of the locomotive, one man shoveling into
+the furnaces the black powder that incloses the energy
+stored in early geological ages, a half dozen men
+mounted on the long train of following vehicles, combine
+to bring to the mill girl in Massachusetts, the
+miner in Pennsylvania, the sewing woman, and the
+wealthy merchant, her neighbor in New York, the
+flour made in Minnesota from the grain harvested a
+few weeks earlier in Dakota. All the world is served
+faithfully and efficiently by this unimaginable power,
+this product of the brain of the inventor, protected by
+the law, stimulated and aided by the capital that it
+has itself almost alone produced.</p>
+
+<p>And thus have the inventors of the steam engine set
+in motion and placed at the disposal of mankind for
+every form of useful work all the great forces of nature;
+thus Hero of Alexandria touched the then concealed
+spring which called all the genii of earth, fire,
+water and air to do the bidding of the race. Thus Papin,
+Worcester, Newcomen, Watt, and Corliss and others
+of our own contemporaries, have applied the genii to
+their task of leveling mountains, traversing seas, continents,
+and the depths of the earth, building ships,
+locomotives, hamlets and cities, cottages and palaces,
+turning the spindle, operating the loom, and setting
+motion and giving energy to every machine, doing the
+work of thousands of millions of men, converting barbarism
+into civilization, giving necessaries of life in
+profusion, comforts in plenty, and luxuries in superabundance.</p>
+
+<p>Aiding and working hand in hand with those other
+genii of progress, the inventors of the printing press
+and of the telegraph, the telephone, and the electric
+railway, of the modern system of textile manufactures,
+of iron and steel making, of the mowing machine and
+the harvester, they have compressed into two centuries
+the progress of a millennium, destitute of their aid.
+Every step taken under their stimulus, and with their
+help, is a step toward a higher life for all, intellectually
+and morally as well as physically; every advance in
+the improvement of their work is a gain to every man,
+woman, and child; every improvement of the steam
+engine is a help to the whole world. This progress
+makes the day of the extinction of the system now
+grinding the populations of the earth into the ground,
+the day of the abolition of armies and the restoration
+to the people of that freedom which characterized the
+times of the patriarchs, and of the restoration of the
+rights of the citizen to his own time and strength and
+producing power, perceptibly nearer.</p>
+
+<p>When this final revolution shall have been accomplished,
+and when all the world has settled down to
+the steady and undisturbed work of production by
+daily and regular labor, aided by the genii of steam,
+of electricity, of all nature, combined for good, the results
+of the intellectual activity of the inventors of the
+steam engine will be fully seen. Then no monument
+will be required to keep green the memory of Watt,
+Corliss, or any other of these great men, but it will be
+said of them, as of Sir Christopher Wren in the epitaph
+in St. Paul's: "Seek you a monument, look about
+you!" Every wreath of steam rising to the heavens
+from factory, mill or workshop will be a reminder of
+Hero of Alexandria, every mine will possess a memorial
+to Papin, Worcester and Savery; every steamship will
+bring into grateful memory Fitch and Stevens, and
+Bell and Fulton; thousands of locomotives, crossing the
+continents, will perpetuate the thought of the Stephensons
+and their colleagues in the introduction of the
+railway; the hum of millions of spindles and the music
+of the electric wire will tell of the work of Corliss and
+his contemporaries and successors who made these
+things possible, and all kingdoms and races, all nations,
+will revere the name of James Watt, the genius to
+whom the world is most indebted for the beginnings of
+all this later and grander civilization which has converted
+the slow progress of earlier centuries into the
+meteor-like advance of to-day toward a future as
+grand and as mighty and as noble as humanity shall
+choose to make it.</p>
+
+<a name="Footnote_1a"></a><a href="#FNanchor_1a">[1]</a><div class="note">
+An address delivered at the Centennial Celebration of the American
+Patent System, Washington, April, 1891.</div>
+
+<hr />
+
+<a name="rr-1"></a><h2>IMPROVED HAND CAR.</h2>
+
+<p class="ctr">
+<img src="images/13a.png" alt="Hand Car Illustration" title="">
+</p>
+
+<p>In the accompanying illustration we show a new design
+of hand car, being introduced by the Courtright
+Manufacturing Co., of Detroit. It will be seen that
+the apparatus for propelling the car is very different
+from the mechanism generally used. An upright framework
+secured to the platform carries a large sprocket
+wheel, which is connected to a smaller one upon one
+of the axles by means of a chain. The larger sprocket
+wheel is rotated by means of a triangular shaped lever
+attached at the lower corner to the crank of the sprocket
+wheel and having a handle at each of its upper corners.
+It is hinged upon a fulcrum which slides upon
+the two vertical rods shown in the illustration. It will
+be seen that this gives a peculiar movement to the
+handles by which the operators propel the car, but it
+has been found that the motion is an excellent one,
+and it is claimed that a higher speed can be obtained
+with the mechanism here shown than with any other
+now in use. There is practically no dead center, as in
+the case where the ordinary crank and lever is used.
+A number of leading roads have given the car a trial,
+and being well satisfied it, have given orders for more.
+The company claim that a car with 20 in. wheels can
+easily be made to attain a speed of 15 miles an hour by
+two men.&mdash;<i>Railway Review</i>.</p>
+
+<hr />
+
+<a name="math-1"></a><h2>THE CONIC SECTIONS.</h2>
+
+<h3>By Prof. C.W. MACCORD, Sc.D.</h3>
+
+<p>In Fig. 1 let D be a given point, and O the center of
+a given circle, whose diameter is FG. Bisect DF at
+A. Also about D describe an arc with any radius DP
+greater than DA, and about O another arc with a radius
+OP = DP + FO, intersecting the first arc at P,
+then draw PD, and also PO, cutting the circumference
+of the given circle in L. Since PD = PL, and
+DA = AF, it is evident that by repeating this process
+we shall construct a curve PAR, which satisfies the
+condition that <i>every point in it is equally distant from
+a given point and from the circumference of a given
+circle</i>. Since PO-PD = LO, and AO-AD = FO,
+this curve is one branch of the hyperbola of which D
+and O are the foci.
+<img src="images/14-fig1.png" align="left" alt="FIG. 1" title="">
+</p>
+
+<p>Bisect DG at B, then about D describe an arc with
+any radius DQ greater than DB, and about O another
+are with radius OQ = DQ-FO; draw from Q the
+intersections of these arcs, the line QD, and also QO,
+producing the latter to cut the circumference in E. By
+this process we may construct the curve QBZ, each
+point of which is also equally distant from the given
+point D, and from the concave instead of the convex
+arc of the given circumference. The difference between
+QD and QO being constant and equal to FO, and AB
+being also equal to FO, this curve is the other branch
+of the same hyperbola, whose major axis is equal to
+the radius of the given circle.</p>
+
+<p>The tangent at P bisects the angle DPL, and is perpendicular
+to DL, which it bisects at a point I on the
+circumference of the circle whose diameter is AB, the
+major axis, the center being C, the middle point of DO.
+As P recedes from A, it is evident that the angles
+P D L, P L D, will increase, until DL assumes the
+position D T tangent to the given circle, when they
+will become right angles. P will therefore be infinitely
+remote, and the point I having then reached t, where
+D T touches the smaller circle, C t S will be an asymptote
+to the curve. This shows that the measurements
+from the convex arc, for the construction of A P, are
+made only from the portion FT of the given circumference.</p>
+
+<p>In the diagram the point Q is so chosen that DL
+produced passes through E, so that QJ, the tangent
+at Q, is parallel to PI. It will thus be seen that the
+measurements from the concave arc, for the construction
+of BQ, are confined to the portion G T of the
+given circumference. As DLE rises, the points P and
+Q recede from A and B, the points L and E approach
+each other, finally coinciding at T; at this instant I
+and J fall together at t, so that S S is the common
+asymptote to A P and B Q.</p>
+
+<p>
+<img src="images/14-fig2.png" align="right" alt="FIG 2." title="">
+In Fig. 2 the given point D lies within the circumference
+of the given circle. Bisect DF at A, and DG
+at B; about D describe an arc with any radius DP
+greater than DA, and about O another, with radius
+OP = OF&nbsp;-&nbsp;DP, these arcs intersect in P, and producing
+OP to cut the circumference in L, we have PD = PL.
+Similarly ED = EH, UD = UW, etc.
+And since PD + PO = LP + PO, DE + EO = HE
++ EO, and so on, the curve is obviously the ellipse of
+which the foci are D and O, and the major axis is AB
+= FO, the radius of the given circle.</p>
+
+<p>If, as in Fig. 3, the given point be made to coincide
+with the center of the circle, the ellipse becomes a
+circle with diameter A B = F O. But if the point be
+placed upon the circumference, as in Fig. 4, the ellipse
+will reduce to the right line A B coinciding with FO.
+
+<img src="images/14-fig3456.png" align="left" alt="FIGs 3, 4, 5, 6." title="">
+</p>
+
+<p>In this case we may also apply the same process as in
+Fig. 1; D T becomes a tangent at D to the circumference,
+and the asymptotes coincide with the axis of the
+hyperbola, of which one branch reduces to the right
+line A P extending from A to infinity on the left, and
+the other reduces to the right line B G Q, extending
+from B to infinity on the right.</p>
+
+<p>If the circle be reduced to a point, as in Fig. 5, the
+resulting locus is a right line perpendicular to and bisecting
+D O. If on the other hand the diameter of the
+given circle be infinite, the circumference, as in Fig. 6,
+becomes a right line perpendicular to the axis at F, and
+the curve satisfies the familiar definition of the parabola,
+D E being equal to E H, D P equal to P L, and
+so on.</p>
+
+
+<p>
+<img src="images/14-fig7.png" align="right" alt="FIG 7." title="">
+In Fig. 7, as in Fig. 1, DT is tangent at T to the
+given circle whose center is O, and at t to the circle
+about C whose diameter is AB, the major axis. Since
+DTO is a right angle, T lies upon the circumference
+of the circle whose center is C, and diameter DO; this
+circle cuts the asymptote SCS at M and N. The
+semi-conjugate axis is a mean proportional between D
+A and AO; now drawing TM and TN, it is seen
+that Tt is that mean proportional; and a circle described
+about C with that radius will be tangent to TO. DT,
+then, is the radius of the circle to be described about the
+focus of the conjugate hyperbola for its construction
+according to the enunciation first given: and we observe
+that DT and TO are supplementary chords in
+the circle about C through D and O. The conjugate
+foci must therefore lie upon this circumference, at D'
+and O'; and since D'O' is perpendicular to DO, D'T
+will be perpendicular and T'O' will be parallel to
+SCS.</p>
+
+
+
+<p>Now as TO increases, T'O' will diminish, until,
+when TO equals DO, T'O' will vanish and with it
+Ct'; and at this crisis, the case is the same as in Fig.
+4; but the conjugate hyperbola logically reduces to
+<i>two</i> right lines, extending from C to infinity on the
+right and left. As indeed it should from the familiar
+construction, since the distances from D' and O' to any
+point on the horizontal axis being equal, their difference
+is constant and equal to zero.</p>
+
+<p>It appears, then, that a conic section may be defined
+as the locus of a point which is equally distant from a
+given point and from the circumference of a given circle.
+Boscovich defines it as the locus of a point so moving
+that its distances from a given point and from a
+given right line shall have a constant ratio.</p>
+
+<p>The latter definition involves the conceptions of a
+rectilinear directrix, and a varying ratio in the cases
+of the different curves, this ratio being unity for the
+parabola, less for the ellipse, and greater for the hyperbola.
+The former involves the conception of a circular
+directrix with a ratio equal to unity in all cases; and
+the two definitions become identical in the construction
+of the parabola, which is in fact the only curve
+of which a clear idea is given by either of them. That
+of Boscovich has been given a prominence far in excess
+of its merits, being made the foundation for the discussion
+of these important curves, and this in a textbook
+whose preface contains the following true and
+emphatic statement, viz.:</p>
+
+<blockquote>
+"The abstract nature of a ratio, and the fact that it
+is a compound concept, peculiarly unfit it for elementary
+purposes."
+</blockquote>
+
+<p>The definition herein set forth has not been given in
+any treatise on the subject, so far as we have been able
+to ascertain. And it is presented with the distinctly
+expressed hope that it never will be, except as a mere
+matter of abstract interest.</p>
+
+<p>Of this it may, like the other, possess a little, but
+both have the great disadvantage that, except in relation
+to the parabola, the idea which they convey to
+the mind of the curves to which they relate, if indeed
+they convey any at all, is most obscure and indirect;
+and of practical utility neither one can claim a particle.</p>
+
+<hr />
+
+<a name="chem-2"></a><h2>TABLE OF ATOMIC WEIGHTS.</h2>
+
+<h3>(Issued December 6, 1890.)</h3>
+
+<p>By request of the Committee of Revision and Publication
+of the Pharmacopoeia of the United States of
+America, Prof. F.W. Clarke, chief chemist of the
+United States Geological Survey, has furnished a table
+of atomic weights, revised upon the basis of the most
+recent data and his latest computations. The committee
+has resolved that this table be printed and furnished
+for publication to the professional press. The
+committee also requests that all calculations and analytical
+data which are to be given in reports or contributions
+intended for its use or cognizance be based
+upon the values in the table. It would be highly desirable
+that this table be adopted and uniformly followed
+by chemists in general, at least for practical
+purposes, until it is superseded by a revised edition. It
+would only be necessary for any author of a paper,
+etc., to state that his analytical figures are based upon
+"Prof. Clarke's table of atomic weights of December
+6, 1890," or some subsequent issue.</p>
+
+<p>This table represents the latest and most trustworthy
+results, reduced to a uniform basis of comparison, with</p>
+
+<p>oxygen = 16 as starting point of the system. No decimal
+places representing large uncertainties are used.
+When values vary, with equal probability on both
+sides, so far as our present knowledge goes, as in the
+case of cadmium (111.8 and 112.2), the mean value is
+given in the table.</p>
+
+<p>The names of elements occurring in pharmaceutical,
+medicinal, chemicals, are printed in italics:</p>
+
+<div class="ctr">
+<table summary="Auto-table" cellspacing="10">
+<colgroup span="3">
+<col align="left">
+<col align="center">
+<col align="center">
+</colgroup>
+<thead>
+<tr><th>Name.</th><th>Symbol.</th><th>Atomic Weight.</th></tr>
+</thead>
+<tbody>
+<tr><td><i>Aluminum.</i></td><td><i>Al</i></td><td>27.  </td></tr>
+<tr><td><i>Antimony.</i></td><td><i>Sb</i></td><td>120.  </td></tr>
+<tr><td><i>Arsenic.</i></td><td><i>As</i></td><td>75.  </td></tr>
+<tr><td><i>Barium.</i></td><td><i>Ba</i></td><td>137.  </td></tr>
+<tr><td><i>Bismuth.</i></td><td><i>Bi</i></td><td>208.9 </td></tr>
+<tr><td><i>Boron.</i></td><td><i>B</i></td><td>11.  </td></tr>
+<tr><td><i>Bromine.</i></td><td><i>Br</i></td><td>79.95 </td></tr>
+<tr><td>Cadmium.</td><td>Cd</td><td>112.  </td></tr>
+<tr><td>Caesium.</td><td>Cs</td><td>132.9 </td></tr>
+<tr><td><i>Calcium.</i></td><td><i>Ca</i></td><td>40.  </td></tr>
+<tr><td><i>Carbon.</i></td><td><i>C</i></td><td>12.  </td></tr>
+<tr><td><i>Cerium.</i></td><td><i>Ce</i></td><td>140.2 </td></tr>
+<tr><td><i>Chlorine.</i></td><td><i>Cl</i></td><td>35.45 </td></tr>
+<tr><td><i>Chromium.</i></td><td><i>Cr</i></td><td>52.1 </td></tr>
+<tr><td>Cobalt.</td><td>Co</td><td>59.  </td></tr>
+<tr><td>Columbium.<a name="FNanchor_1b"></a><a href="#Footnote_1b"><sup>1</sup></a></td><td>Cb</td><td>94.  </td></tr>
+<tr><td><i>Copper.</i></td><td><i>Cu</i></td><td>63.4 </td></tr>
+<tr><td>Didymium.<a name="FNanchor_2"></a><a href="#Footnote_2"><sup>2</sup></a></td><td>Di</td><td>142.3 </td></tr>
+<tr><td>Erbium.</td><td>Er</td><td>166.3 </td></tr>
+<tr><td>Fluorine.</td><td>F</td><td>19.  </td></tr>
+<tr><td>Gallium.</td><td>Ga</td><td>69.  </td></tr>
+<tr><td>Germanium.</td><td>Ge</td><td>72.3 </td></tr>
+<tr><td>Glucinum.<a name="FNanchor_3"></a><a href="#Footnote_3"><sup>3</sup></a></td><td>Gl</td><td>9.  </td></tr>
+<tr><td><i>Gold.</i></td><td><i>Au</i></td><td>197.3 </td></tr>
+<tr><td><i>Hydrogen.</i></td><td><i>H</i></td><td>1.007  </td></tr>
+<tr><td>Indium.</td><td>In</td><td>113.7 </td></tr>
+<tr><td><i>Iodine.</i></td><td><i>I</i></td><td>126.85  </td></tr>
+<tr><td>Iridium.</td><td>Ir</td><td>193.1 </td></tr>
+<tr><td><i>Iron.</i></td><td><i>Fe</i></td><td>56.  </td></tr>
+<tr><td>Lanthanum.</td><td>La</td><td>138.2 </td></tr>
+<tr><td><i>Lead.</i></td><td><i>Pb</i></td><td>206.95 </td></tr>
+<tr><td><i>Lithium.</i></td><td><i>Li</i></td><td>7.02  </td></tr>
+<tr><td><i>Magnesium.</i></td><td><i>Mg</i></td><td>24.3 </td></tr>
+<tr><td><i>Manganese.</i></td><td><i>Mn</i></td><td>55.  </td></tr>
+<tr><td><i>Mercury.</i></td><td><i>Hg</i></td><td>200.  </td></tr>
+<tr><td><i>Molybdenum.</i></td><td><i>Mo</i></td><td>96.  </td></tr>
+<tr><td>Nickel.</td><td>Ni</td><td>58.7 </td></tr>
+<tr><td><i>Nitrogen.</i></td><td><i>N</i></td><td>14.03  </td></tr>
+<tr><td>Osmium.</td><td>Os</td><td>191.7 </td></tr>
+<tr><td><i>Oxygen</i>.<a name="FNanchor_4"></a><a href="#Footnote_4"><sup>4</sup></a></td><td><i>O</i></td><td>16.  </td></tr>
+<tr><td>Palladium.</td><td>Pd</td><td>106.6 </td></tr>
+<tr><td><i>Phosphorus.</i></td><td><i>P</i></td><td>31.  </td></tr>
+<tr><td>Platinum.</td><td>Pt</td><td>195.  </td></tr>
+<tr><td><i>Potassium.</i></td><td><i>K</i></td><td>39.11 </td></tr>
+<tr><td>Rhodium.</td><td>Rh</td><td>103.5 </td></tr>
+<tr><td>Rubidium.</td><td>Rb</td><td>85.5 </td></tr>
+<tr><td>Ruthenium.</td><td>Ru</td><td>101.6 </td></tr>
+<tr><td>Samarium.</td><td>Sm</td><td>150.  </td></tr>
+<tr><td>Scandium.</td><td>Sc</td><td>44.  </td></tr>
+<tr><td>Selenium.</td><td>Se</td><td>79.  </td></tr>
+<tr><td><i>Silicon.</i></td><td><i>Si</i></td><td>28.4 </td></tr>
+<tr><td><i>Silver.</i></td><td><i>Ag</i></td><td>107.92  </td></tr>
+<tr><td><i>Sodium.</i></td><td><i>Na</i></td><td>23.05  </td></tr>
+<tr><td>Strontium.</td><td>Sr</td><td>87.6 </td></tr>
+<tr><td><i>Sulphur.</i></td><td><i>S</i></td><td>32.06  </td></tr>
+<tr><td>Tantalum.</td><td>Ta</td><td>182.6 </td></tr>
+<tr><td>Tellurium.</td><td>Te</td><td>125.  </td></tr>
+<tr><td>Terbium.</td><td>Tb</td><td>159.5 </td></tr>
+<tr><td>Thallium.</td><td>Tl</td><td>204.18  </td></tr>
+<tr><td>Thorium.</td><td>Th</td><td>232.6 </td></tr>
+<tr><td>Tin.</td><td>Sn</td><td>119.  </td></tr>
+<tr><td>Titanium.</td><td>Ti</td><td>48.  </td></tr>
+<tr><td>Tungsten.</td><td>W</td><td>184.  </td></tr>
+<tr><td>Uranium.</td><td>U</td><td>239.6 </td></tr>
+<tr><td>Vanadium.</td><td>V</td><td>51.4 </td></tr>
+<tr><td>Yterbium.</td><td>Yb</td><td>173.  </td></tr>
+<tr><td>Yttrium.</td><td>Yt</td><td>89.1 </td></tr>
+<tr><td><i>Zinc.</i></td><td><i>Zn</i></td><td>65.3 </td></tr>
+<tr><td>Zirconium.</td><td>Zr</td><td>90.6 </td></tr>
+</tbody>
+</table></div>
+
+
+<p>&mdash;<i>Am. Jour. Pharm.</i></p>
+
+<a name="Footnote_1b"></a><a href="#FNanchor_1b">[1]</a><div class="note">Has priority over niobium.</div>
+<a name="Footnote_2"></a><a href="#FNanchor_2">[2]</a><div class="note">Now split into neo-and praseo-didymium.</div>
+
+<a name="Footnote_3"></a><a href="#FNanchor_3">[3]</a><div class="note">Has priority over beryllium.</div>
+
+<a name="Footnote_4"></a><a href="#FNanchor_4">[4]</a><div class="note">Standard, or basis of the system.</div>
+
+<hr />
+
+
+<a name="tec-1"></a><h2>THE TANNING MATERIALS OF EUROPE.</h2>
+
+<p>The tanning materials of Europe are of an altogether
+different type from those of the United States.
+The population is so dense that the quantity of home
+materials produced is not nearly proportionate to the
+amount consumed, and consequently they must draw
+upon surrounding lands for their supply. The vegetation
+of these adjacent countries is of a much more
+tropical nature, and it naturally follows that the
+tanning materials are also of a different species.</p>
+
+<p>Tanning materials may be divided into two great
+classes, viz.: Physiological and pathological.</p>
+
+<h3>PHYSIOLOGICAL.</h3>
+
+<p>The first class includes those tannins which are the
+results of perfectly natural or normal growth, and a
+growth necessary to the development of vegetation,
+for instance, bark, sumac, etc., whereas the second
+class contains those which are the results of abnormal
+growth, caused by diseases, stings of insects, etc. An
+example of this is the gall. Both of these classes are
+used to a great extent in Europe, while only the first
+division is in general use in the United States. We will
+first consider the physiological tannins.</p>
+
+<p><i>Oak Bark.</i>&mdash;This material was, is, and will be for
+some time to come the main tanning material in use
+here in Europe. The advantages of the oak tannage
+are as fully appreciated here as in the United States.
+The European oak gives a light colored, firm leather,
+with good weight results, is comparatively cheap and
+of an excellent quality. The varieties are numerous,
+each country having its own kind. Those in most
+general use are:</p>
+
+<p><i>Spiegel Rinde</i> (mirror bark).&mdash;This bark is well
+distributed throughout Europe, and is peeled when the
+tree has attained a growth of from 12 to 24 years. It
+is marketed in three grades.</p>
+
+<p><i>Reitel Rinde</i>&mdash;Is obtained from the same tree as the
+spiegel rinde, but after the tree has attained a growth
+of from 25 to 40 years.</p>
+
+<p><i>Alte Pische</i> (old oak).&mdash;Obtained from the aged tree.
+It is not as valuable as the younger bark, and consequently
+brings a much lower price.</p>
+
+<p>Spiegel rinde may be judged by small warts which
+appear on the shining surface of the bark. The presence
+of a great number of these, as a rule, indicates a
+high tannin percentage.</p>
+
+<p>Bosnia has fine oak trees, the bark containing 10 to
+11 per cent. tannin.</p>
+
+<p>Bohemia has the <i>trauben eiche</i> (grape oak).</p>
+
+<p>France uses the kirmess oak, which grows in the
+south of that country and in northern Africa. Two
+grades are made, viz., root and trunk.</p>
+
+<p>Tyrol has the evergreen oak&mdash;12 to 13 per cent. tannin.</p>
+
+<p>Sardinia possesses a cork oak, which yields 13 to 14 per cent.</p>
+
+<p>White oak is found throughout Europe, yielding 10
+per cent. The price of oak bark varies a great deal.
+The assortment is much more strict than in the United
+States. In Austria it brings 4 to 5 fl., equal to $1.60 to
+$2 per kilo. (224 lb.); in Germany, 11 to 16 marks per
+100 kilos.<a name="FNanchor_1c"></a><a href="#Footnote_1c"><sup>1</sup></a></p>
+
+<p>The above mentioned varieties are all used for both
+upper and sole leather. In Germany a great deal of
+upper leather is pure oak tannage, but one seldom finds
+a pure oak tanned sole leather; it is almost always in
+combination with other tannics.</p>
+
+<p><i>Pine Bark</i>&mdash;Is well distributed and is a very
+important tanning material. It bears the same relation
+to oak bark here as does hemlock in America, but its
+effects are quite different from hemlock. The best
+Austrian sorts are those of Styria and Bohemia, but
+that of Karuthen is also of good quality. The German
+pine comes from Thuringia to a great extent. The
+countries that consume the greatest amount of pine
+bark are Austria, Germany, Russia and Italy. The
+tannin contained varies from 5 to 16 per cent. Its
+use is almost wholly confined to the handlers, as its
+weight returns are not so satisfactory as oak or valonia.
+In case it should be used for layers it is always in
+combination with some better weight-giving tannic. For
+upper leather its use is limited.</p>
+
+<p>The bark is always peeled from the felled tree, and
+often the woodman accepts the bark in part payment
+for his labor; he then sells the bark to the tanner or
+agents who go about the country collecting bark. It
+is generally very nicely cleaned. I would here like to
+correct a mistake which tanners often make in their
+estimations of the value of barks. A tanner usually
+buys the bark of southern-grown trees in preference to
+that of trees grown in northern countries, as it is a
+common idea that southern vegetation contains more
+tannin than that of the north. This is a fallacy, as has
+not only been proved by careful analyses, but may
+also be found to be an incorrect conclusion after a
+moments' thought. Those trees which flourish in
+southern countries grow very rapidly, and as tannin is
+necessary to the development of leaf structure, etc., it
+is absorbed to a greater extent than is the case with
+the slower-growing tree of the north. The tannin
+contained in the sap does not increase in the same ratio
+as does the rapid growth, and it follows that the remainder
+in the bark is less than in the tree of slower growth.</p>
+
+<p><i>Birch Bark</i>&mdash;Is at home in Russia, Norway, and
+Sweden. It is used for both upper and sole leather,
+but seldom alone. The bark is usually peeled from
+the full grown tree, and contains 4 to 9 per cent.
+tannin.</p>
+
+<p><i>Willow Bark</i>&mdash;May also be found in the above
+mentioned countries and also in Germany. This material
+is used for both upper and sole leather, and contains
+6 to 9 per cent. tannin. It is a very delicate material
+to use, as its tannin decomposes rapidly.</p>
+
+<p><i>Erlen Rinde</i>&mdash;Is also a native of Germany, but is
+not used to any great extent. The same may be said of
+the larch, although this variety is also to be met with
+in Russia.</p>
+
+<p><i>Mimosa Bark</i>&mdash;Is obtained from the acacia of
+Australia. It is a favorite in England. The varieties are
+as follows: Gold wattle, silver wattle (blackwood,
+lightwood), black wattle, green wattle. The gold wattle
+is a native of Victoria. Its cultivation was tried as
+an experiment in Algeria and met with some success.
+
+The trees are always grown from seeds. These seeds
+are laid in warm water for a few hours before sowing.
+The acacia may be peeled at eight years' growth and
+carries seeds. The Tasmania bark is very good; that
+from Adelaide likewise good.</p>
+
+<p>Sydney does not produce so good an article, but
+Queensland better. The bark is marketed in the stick,
+ground or chopped.</p>
+
+<p>Madagascar and the Reunion Islands have also a
+mimosa bark.</p>
+
+<p>The mimosa barks give a reddish colored leather,
+pump well and contain a high tannin percentage, 10 to
+35 per cent.</p>
+
+<p>Now we will consider the fruit tanning materials.</p>
+
+<p>Valonia may truly be called one of the most generally
+used tanning agents at present employed in Europe.
+All countries consume it more or less. Valonia was
+first used in England about the beginning of this century.
+A few years later Germany began using it, and
+still later Austria introduced it. It is the fruit of the
+oak tree and is obtainable in Asia Minor and the adjacent
+islands. In form it resembles the American
+acorn, but in size it nearly trebles it. The fruit may
+be divided into two parts, namely, the cup and acorn,
+and the cup again divided into trillor and inner cup.
+The acorn only contains 10 per cent. tannin, whereas
+the cup contains from 25 to 40 per cent.</p>
+
+<p>The percentage depends altogether upon the time of
+harvesting and the place of growth. The best valonia
+is derived from Smyrna, and is naturally the highest
+priced article. Valonia is worth from 22 to 28 florins
+($9 to $11) per 100 kilos. (224 pounds) at present. The
+other provinces and islands from which it is obtainable
+are Demergick, Govalia, Idem, Ivalzick, Troy (this is
+the best); Metelino Island, the vicinity of Smyrna.
+The material sold in three grades&mdash;prime, mazzano;
+seconds, una aqua; thirds, skart.</p>
+
+<p>The product of Smyrna generally averages:</p>
+
+<div class="ctr"><table summary="product of smyrna" border="0" cellspacing="5">
+<tr><td> </td><td>Tons.</td><td>Price.</td></tr>
+<tr><td>Prime.</td><td>2,000 to  3,000</td><td>28 florins.</td></tr>
+<tr><td>Seconds.</td><td>5,000 to 10,000</td><td>25 florins.</td></tr>
+<tr><td>Thirds.</td><td>20,000 to 30,000</td><td> 22 florins.</td></tr>
+</table></div>
+
+<p>The <i>Metilino</i> valonia is a product of a neighboring
+island, and is a very good article. It may be easily
+distinguished by its thin cup. It is harvested in September.</p>
+
+<p>The <i>Candia</i> valonia is nearly as long as it is wide, in
+contrast to the Smyrna, which is much wider than long.
+The recent harvest showed a return of 800 to 1,000 tons,
+but no assortment is made. A grade called the Erstlige
+is sold, this being the first which has fallen to the
+ground before maturing.</p>
+
+<p>A peculiarity of the valonia is that it often strikes
+out a sort of sugar sweat, which gives the cup a less
+attractive appearance, but denotes the presence of large
+quantities of tannin.</p>
+
+<p>Valonia is used almost wholly for sole leather, either
+alone or in combination with pine or oak bark or
+knoppern and myrabolams. The union of valonia and
+knoppern is that in most general use. Valonia gives the
+leather a yellowish appearance, as it deposits a great
+deal of yellow bloom. The leather is very firm and
+of good wearing qualities. The weight results are
+also excellent, as will be seen below. To sole leather
+there are usually given from one to three layers of
+valonia. The demand for valonia is increasing more
+and more every year, and the present outlook does not
+indicate any relaxation of its popularity. Its use for
+upper leather is very limited.</p>
+
+<p>Myrabolams are mainly used in England and Austria,
+and give a nice light-colored leather, both upper and
+sole, although rarely used alone. Their main use is for
+dyeing purposes. They are indigenous to the East
+Indies.</p>
+
+<p>Sumac is so well known that treating of it is superfluous.
+Its use is very extensive, and it is a general
+favorite for light, fine leather, which is mostly used
+for colors.</p>
+
+<p><i>Gambier</i>&mdash;Is in general use in England and to some
+extent in Germany.</p>
+
+<p><i>Catechu</i>.&mdash;Obtained from India, resembles gambier
+greatly. Its use is almost wholly confined to England.
+It is also consumed by the silk manufacturers in preference
+to gambier, for weighting purposes.</p>
+
+<h3>PATHOLOGICAL.</h3>
+
+<p>We now leave the physiological class and take up
+those tanning materials included in the pathological
+class, or those of abnormal growth.</p>
+
+<p><i>Galls</i>.&mdash;These are not consumed to any great extent
+at the present period, but formerly they were used
+quite extensively. The galls are found upon the leaves
+of the oak or sumac, etc. The direct cause of their
+growth is that a certain wasp (cynips galles) stings into
+the leaf and after depositing its egg, flies away. The
+egg develops into a larva and then into a full-fledged
+wasp, boring its way out of the gall which has served
+as a protection and nourisher. This accounts for the
+hole noticed in almost every gall. The different varieties
+include Aleppo. It is found upon the same trees as the
+valonia and contains 60 to 75 per cent. tannin; Istrian
+galls, 32 per cent. tannin; Persian, 28 to 29 per cent.
+tannin. Chinese galls, giving 80 to 82 per cent. tannin,
+are the results of the sting of a louse, and make a very
+light-colored leather. The dyers also use this material
+for coloring.</p>
+
+<p><i>Knoppern</i>&mdash;Belongs to the family of galls, and is a
+most important factor of commerce in Austria. The
+knopper is generally found on the acorn or leaf of the
+oak tree. The greatest quantity is derived from the
+steel oak of Hungary. The tannin contained varies
+from 27 to 33 per cent. Knoppern are not being used
+so much now as formerly, and consequently the amount
+harvested lessens from year to year. Its main use was
+and is in combination with valonia as layers for sole
+leather. Valonia gives better weight results than
+knoppern, and is replacing knoppern more and more
+every year. The combination of knoppern, valonia
+and myrabolams is also quite popular, and gives
+good results. Knoppern are seldom used alone, being
+generally combined with some other tannin. Austria
+is almost the only consumer at present, but Germany
+used it extensively formerly.</p>
+
+<p><i>Bark and Wood Extracts</i>&mdash;Are becoming general
+favorites throughout Europe, partly because of their
+weight-giving qualities and partly as the transportation
+costs so little; they can be used to strengthen weak
+bark liquors.</p>
+
+
+<p><i>Oak Extracts</i>&mdash;Are well liked, both wood and bark,
+and are used extensively. Slavonia furnishes a great
+deal of it.</p>
+
+<p><i>Chestnut Oak Wood Extract</i>&mdash;Is manufactured in
+quantities, and easily finds purchasers.</p>
+
+<p><i>Pine Bark Extract</i>&mdash;Is also consumed in goodly
+amounts.</p>
+
+<p><i>Quebracho Wood Extract</i>.&mdash;The wood is shipped from
+Brazil to Hamburg and other ports, and the tannin
+extracted there. Hamburg furnishes quantities
+of it.</p>
+
+<p><i>Hemlock Extract</i>&mdash;Is used in Russia, and seems to
+have taken a hold on the shoe buyers' fancies, as they
+now make imitations of it in color. The hemlock that
+is consumed is imported from America.</p>
+
+<p>As most leather is sold by weight in Europe, the
+leather manufacturers aim to obtain as good weight
+results as possible, and often, I am sorry to say, do so
+at the sacrifice of quality. This is common to both
+upper and sole leather. Sole leather is nine times out
+of ten given false weight by forcing entirely foreign
+substances into the leather, such as glucose, barium
+chloride, magnesium chloride, resins, etc. Glucose and
+resin are also used for weighting upper leather. Leather
+is also weighted with extracts by overtanning. Leather
+buyers have become very wary of late and do not purchase
+large quantities before an analysis is made of a
+fair sample.</p>
+
+<p>One more word before I close. The governments and
+private individuals in Europe cultivate and raise trees
+for both lumber and bark purposes. The forests are
+excellently cared for by efficient foresters, and the result
+is that the tanners obtain much cleaner and better
+bark, and of a very even quality. Would it not be a
+good idea if some individual, who would certainly earn
+the everlasting gratefulness of the tanners, would look
+into this matter, and see that not only the lumber side
+of our forest cultivation is not neglected, but that the
+bark also is preserved and cared for? Of course, we
+can obtain all the bark necessary at present and for
+some time to come, but the time will come when we
+shall certainly regret not having taken these steps, if
+the lumbermen and bark peelers go on devastating
+magnificent forests. Below will be found a table of
+weight results. Sole leather tanned with these materials
+gives for every 100 lb. green hide the following
+quantities of finished leather:</p>
+
+<div class="ctr"><table summary="Tannic Tanned Weights" border="0" cellspacing="5">
+<tr>
+<td> </td>
+<td> lb. </td>
+</tr>
+<tr><td>Oak bark</td><td>48 to 54</td></tr>
+<tr><td>Oak extract</td><td>55 to 56</td></tr>
+<tr><td>Pine bark </td><td>44 to 46</td></tr>
+<tr><td>Pine extract</td><td> 48 to 50</td></tr>
+<tr><td>Willow </td><td>45 to 46</td></tr>
+<tr><td>Birch bark and oak extract</td><td>49 to 51</td></tr>
+<tr><td>Quebracho wood and extract </td><td>48 to 49</td></tr>
+<tr><td>Valonia </td><td>52 to 56</td></tr>
+<tr><td>Knoppern </td><td>51 to 53</td></tr>
+<tr><td>Myrabolams </td><td>50</td></tr>
+<tr><td>Knoppern, myrabolams and valonia</td><td>52 to 53</td></tr>
+<tr><td>Hemloc</td><td>55</td></tr>
+</table></div>
+
+<p>Specification of tanning materials used in different
+countries:</p>
+
+<pre>
+   <i>France.</i>
+      Oak bark (kirmess).
+      Sumac.
+      Chestnut wood extract.
+      Quebracho "     "
+      Some gambier.
+
+   <i>Italy.</i>
+      Oak bark.
+      Pine "
+      Sumac.
+      Valonia.
+
+   <i>England.</i>
+      Oak bark.
+      Divi divi.
+      Myrabolams.
+      Valonia.
+      Mimosa.
+      Extracts { Oak bark and wood hemlock.
+      Gambier.
+      Cutch.
+
+   <i>Germany and Austria.</i>
+      Oak bark.
+      Pine "
+      Willow bark.
+      Valonia.
+      Knoppern.
+      Myrabolams.
+               { Oak bark and wood.
+      Extracts { Pine bark and wood.
+
+   <i>Russia.</i>
+      Birch bark.
+      Willow "
+      Oak    "
+      Pine   "
+      Hemlock extract.
+
+
+   <i>Norway and Sweden.</i>
+      Birch bark.
+      Willow "
+      Oak    "
+
+</pre>
+
+<div style="margin-left: 10em; ">WALTER J. SALOMON.<br/><br />
+&mdash;<i>Shoe and Leather Reporter.</i></div>
+
+<a name="Footnote_1c"></a><a href="#FNanchor_1c">[1]</a><div class="note">
+In the principal districts in America, removed from the cities,
+the price of oak bark is about $4 to $6 per cord or per ton
+of 2,240 lb. The hemlock bark, which gives a sole leather just as
+thoroughly tanned, but of a darker and reddish color, costs the
+larger tanners from $3 to $4 a cord.</div>
+
+<hr />
+
+<a name="chem-1"></a><h2>AN APPARATUS FOR HEATING SUBSTANCES
+IN GLASS TUBES UNDER PRESSURE.<a name="FNanchor_1d"></a><a href="#Footnote_1d"><sup>1</sup></a></h2>
+
+<h4>By H. PEMBERTON, Jr.</h4>
+
+<p>Chemists who do not happen to have in their laboratories
+oil or air baths for heating closed tubes can
+make an air bath at short notice from materials furnished
+by all dealers in steam fittings.</p>
+
+<p><i>Order</i>:</p>
+
+<p>(1) One four-inch wrought iron pipe, eighteen inches
+out to out, with usual thread on each end. At about
+nine inches from either end this pipe is drilled and tapped
+for a one-inch nipple, in such a manner that a pipe
+introduced would pass, not on a line with the radius,
+but about half way between the axis of the four-inch
+pipe and its walls; in other words, it would be on a
+line with a chord of the circle.</p>
+
+<p>(2) One one-inch wrought iron nipple, two inches
+long, one-inch thread on one end.</p>
+
+<p>(3) Two four-inch malleable iron caps, drilled and
+tapped for a one-inch pipe.</p>
+
+<p>(4) One one-inch wrought iron pipe, twenty-four
+inches out to out, with a three-inch straight thread
+on each end.</p>
+
+<p>(5) Two one-inch iron caps. A hole, one-eighth of an
+inch in diameter, is drilled in the end of one of these
+caps.</p>
+
+<p>The above order can be given <i>literatim</i>, and will be
+understood by the dealer, who will furnish, at a trifling
+cost, the materials, cut and tapped as ordered.</p>
+
+<p>
+<img src="images/16-fig12.png" align="left" alt="FIG. 1." title="">
+Fig. 1 shows how the whole is put together. The
+numbers on the figure correspond also to the numbers
+of the paragraphs of the order as given above.</p>
+
+<p>Fig. 2 is an end section. A cork is inserted in 2 and
+through it a thermometer, the bulb of which is on a
+level with the interior pipe. The whole is supported
+on a few bricks at either end, and is kept steady and
+in place by a couple of weights or half bricks. It is
+heated by one or two Bunsen burners, according to the
+temperature desired.&mdash;<i>Jour. Fr. Institute</i>.</p>
+
+<a name="Footnote_1d"></a><a href="#FNanchor_1d">[1]</a><div class="note">Read at the meeting of the Chemical Section of the Franklin Institute
+held March 17, 1891.</div>
+
+<hr />
+
+<a name="chem-3"></a><h2>TESTING CEMENT.</h2>
+
+<p>An improved method of testing Portland cement has
+been adopted by M. Deval, Chief Superintendent of
+Bridges and Roads, who has charge, under M. Saele,
+of the Public Works Laboratory of the City of Paris.
+The principal difference in M. Deval's method consists
+in the use of hot water for the period of hardening. The
+briquettes are made in the usual way, and of the ordinary
+size; and the cement to be tested is gauged with
+three times its weight of normal sand, and the smallest
+quantity of water possible. After preparation, the
+briquettes are allowed to harden in air for a period
+ranging from 24 hours for Portland cement to 30 days
+for certain slow-setting hydraulic limes. After this
+period, the samples are immersed in water kept at a
+temperature of 80° C., in which they remain for from
+two to seven days. The briquettes are then broken in
+the ordinary way. After careful comparisons of many
+varieties of cement hardened hot and cold, M. Deval
+finds that cold tests are fallacious, inasmuch as they
+may fail to detect bad material. Portland cement of
+good quality will not only stand water at 80° C., but
+will attain in seven days about the same strength as is
+reached in the cold after 28 days. The hot test therefore
+saves time. The hot test is an unfailing proof for
+free lime; cements containing this constituent betraying
+weakness, and cracking, swelling, and disintegrating
+in a very significant manner. This last result
+is regarded as a valuable quality of the new method of
+testing cement, the general effect of which appears to
+be to enhance the test value of really good cements,
+while depreciating those of an inferior character.</p>
+
+<hr />
+
+<h2>THE SCIENTIFIC AMERICAN
+Architects and Builders Edition</h2>
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+
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+
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+
+
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+<h2>PATENTS!</h2>
+
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+
+<p>In this line of business they have had <i>forty-five years' experience</i>, and
+now have <i>unequaled facilities</i> for the preparation of Patent Drawings,
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+
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+
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+
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+  361 Broadway, New York.</h4>
+
+<p class="ctr">BRANCH OFFICES.&mdash;No. 622 and 624 F Street, Pacific Building,<br />
+near 7th Street, Washington, D.C.</p>
+
+<div>*** END OF THE PROJECT GUTENBERG EBOOK 13358 ***</div>
+</body>
+</html>
+
+
+
+
+
+
+
+
+
+
+
+
+
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+This eBook, including all associated images, markup, improvements,
+metadata, and any other content or labor, has been confirmed to be
+in the PUBLIC DOMAIN IN THE UNITED STATES.
+
+Procedures for determining public domain status are described in
+the "Copyright How-To" at https://www.gutenberg.org.
+
+No investigation has been made concerning possible copyrights in
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+status under the laws that apply to them.
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+Project Gutenberg (https://www.gutenberg.org) public repository for
+eBook #13358 (https://www.gutenberg.org/ebooks/13358)
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+The Project Gutenberg EBook of Scientific American Supplement, No. 803,
+May 23, 1891, 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: Scientific American Supplement, No. 803, May 23, 1891
+
+Author: Various
+
+Release Date: September 3, 2004 [EBook #13358]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Victoria Woosley and the
+Online Distributed Proofreading Team.
+
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 803
+
+
+
+
+NEW YORK, May 23, 1891
+
+Scientific American Supplement. Vol. XXXI., No. 803.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+
+         *       *       *       *       *
+
+
+
+
+TABLE OF CONTENTS.
+
+
+I.    ASTRONOMY.--The Great Equatorial of the Paris Observatory.--
+      The new telescope recently put in use in Paris.--Description of
+      the instrument and of its effects.--3 illustrations
+
+II.   CHEMISTRY.--An Apparatus for Heating Substances in Glass
+      Tubes under Pressure.--By H. PEMBERTON, Jr.--A simple apparatus
+      for effecting this purpose, avoiding risk of personal injury.--
+      2 illustrations
+
+      Table of Atomic Weights.--A revised table of atomic weights,
+      giving the results of the last determinations, and designed for
+      every-day use
+
+      Testing Cement.--A laboratory process for testing Portland cement
+
+III.  CIVIL ENGINEERING.--The Compressed Air System of Paris.
+      --An elaborate review of this great installation for the transmission
+      of power.--The new compressed air station, with full details
+      of performances of apparatus, etc.--10 illustrations
+
+IV.   ENTOMOLOGY.--Report on Insects.--Continuation of this report
+      on noxious insects.--Their habits and how to cope with them.
+      --18 illustrations
+
+V.    FLORICULTURE.--Lily of the Valley.--Practical notes on the
+      cultivation of this popular flower.--How to raise it and force the
+      growth
+
+VI.   MATHEMATICS.--The Conic Sections.--By Prof. C.W.
+      MACCORD.--Examination of the four conic sections with a general
+      definition applicable to all.--6 illustrations
+
+VII.  MECHANICAL ENGINEERING.--The Builders of the Steam
+      Engine--The Founders of Modern Industries and Nations.--By Dr.
+      R.H. THURSTON.--Prof. Thurston's address before the Centennial
+      Celebration of the American Patent System at Washington,
+      D.C.--The early history of the steam engine and its present position
+      in the world
+
+VIII. MISCELLANEOUS.--The Breeds of Dogs.--Popular description
+      of the different breeds of dogs most affected by amateurs.--6
+      illustrations
+
+IX.   NAVAL ENGINEERING.--Modern Armor.--By F.R. BRAINARD.--The
+      development of modern ship armor, from laminated
+      sandwiched and compound types to the present solid armor.--9
+      illustrations
+
+X.    PISCICULTURE.--Restocking the Seine with Fish.--The introduction
+      of 40,000 fry of California trout and salmon, designed to restock
+      the Seine, depopulated of fish by explosions of dynamite
+      used in breaking up the ice.--1 illustration
+
+XI.   RAILWAY ENGINEERING.--Improved Hand Car.--A novelty
+      in the construction of hand cars, avoiding the production of a
+      dead center.--1 illustration
+
+XII.  TECHNOLOGY.--The Tanning Materials of Europe.--The natural
+      tanning materials and pathological or abnormal growth tanning
+      materials described and classified, with relative power
+
+
+         *       *       *       *       *
+
+
+
+
+THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.
+
+
+The great instrument which has just completed the installation of our
+national observatory is constructed upon the same principle as the
+elbowed equatorial, 11 in. in diameter, established in 1882, according
+to the ingenious arrangement devised as long ago as 1872, by Mr.
+Loewy, assistant director of the Paris Observatory.
+
+We shall here recall the fact that the elbowed equatorial consists of
+two parts joined at right angles. One of these is directed according
+to the axis of the world, and is capable of revolving around its own
+axis, and the other, which is at right angles to it, is capable of
+describing around the first a plane representing the celestial
+equator. At the apex of the right angle there is a plane mirror of
+silvered glass inclined at an angle of 45 deg. with respect to the
+optical axis, and which sends toward the ocular the image coming from
+the objective and already reflected by another and similar plane
+mirror. The objective and this second mirror (which is inclined at an
+angle of 45 deg.) are placed at the extremity of the external part of
+the tube, and form part of a cube, movable around the axis of the
+instrument at right angles with the axis of the world. The diagram in
+Fig. 3 will allow the course of a luminous ray coming from space to be
+easily understood. The image of the star, A, toward which the
+instrument is directed, traverses the objective, B C, is reflected
+first from the mirror, B D, and next from the central mirror, E F, and
+finally reaches O, at the ocular where the observer is stationed.
+
+This new equatorial differs from the first model by its much larger
+dimensions and its extremely remarkable mechanical improvements. The
+optical part, which is admirably elaborated, consists of a large
+astronomical objective 24 in. in diameter, and of a photographic
+objective of the same aperture, capable of being substituted, one for
+the other, according to the nature of the work that it is desired to
+accomplish by the aid of this colossal telescope, the total length of
+which is 59 ft. The two plane mirrors which complete the optical
+system have, respectively, diameters of 34 in. and 29 in. These two
+magnificent objectives and the two mirrors were constructed by the
+Brothers Henry, whose double reputation as astronomers and opticians
+is so universally established. The mechanical part is the successful
+work of Mr. Gautier, who has looked after every detail with the
+greatest care, and has thus realized a true _chef d'oeuvre_. The
+colossal instrument, the total weight of which is 26,400 lb., is
+maneuvered by hand with the greatest ease. A clockwork movement, due
+to the same able manufacturer, is capable, besides, of moving the
+instrument with all the precision desirable, and of permitting it to
+follow the stars in their travel across the heavens. A star appearing
+in the horizon can thus be observed from its rising to its setting.
+The astronomer, his eye at the ocular, is always conveniently seated
+at the same place, observing the distant worlds, rendered immovable,
+so to speak, in the field of the instrument. For stars which, like the
+moon and the planets, have a course different from the diurnal motion,
+it is possible to modify the running of the clockwork, so that they
+can thus be as easily followed as in the preceding case. Fig. 1 gives
+a general view of the new installation, for which it became necessary
+to build a special edifice 65 ft. in height on the ground south of the
+observatory bordering on the Arago Boulevard. A large movable
+structure serves for covering the external part of the instrument.
+This structure rests on rails, upon which it slides toward the south
+when it is desired to make observations. It will be seen from the
+figure how the principal axis of the instrument rests upon the two
+masonry pillars, one of which is 49 ft. and the other 13 ft. in
+height.
+
+[Illustration: FIG 1.--THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.]
+
+The total cost of the pavilion, rolling structure, and instrument
+(including the two objectives) will amount to about $80,000 after the
+new equatorial has been provided with the scientific apparatus that
+necessarily have to accompany it for the various and numerous
+applications to which the use of it will give rise.
+
+[Illustration: FIG 2.--OCULAR OF THE GREAT EQUATORIAL.]
+
+Fig. 2 shows us the room in the observatory in which the astronomer,
+seated in his chair, is completely protected against the inclemencies
+of the weather. Here, with his eye applied to the ocular, he can,
+without changing position (owing to all the handles that act at his
+will upon the many transmissions necessary for the maneuvering),
+direct his instrument unaided toward every point of the heavens with
+wonderful sureness and precision. The observer has before him on the
+same plane two divided circles, one of which gives the right
+ascensions and the other the declinations, and which he consults at
+each observation for the exact orientation of the equatorial.
+
+[Illustration: FIG. 3.--DIAGRAM SHOWING THE COURSE OF A LUMINOUS RAY
+IN THE GREAT EQUATORIAL.]
+
+All the readings are done by the aid of electric lamps of very small
+dimensions, supplied by accumulators, and which are lighted at will.
+Each of these lamps is of one candle power; two of them are designed
+for the reading of the two circles of right ascension and of
+declination; a third serves for the reading of the position circle of
+the micrometer; two others are employed for the reading of the drums
+fixed upon the micrometric screws; four others serve for rendering the
+spider threads of the reticule brilliant upon a black ground; and
+still another serves for illuminating the field of the instrument
+where the same threads remain black upon a luminous ground. The
+currents that supply these lamps are brought over two different
+circuits, in which are interposed rheostats that permit of graduating
+the intensity of the light at will.
+
+Since the installation of the first model of an elbowed equatorial of
+11 in. aperture, in 1882, at the Paris Observatory, the numerous and
+indisputable advantages of this sort of instrument have led a certain
+number of observatories to have similar, but larger, instruments
+constructed. In France, the observatories of Alger, Besancon, and
+Lyons have telescopes of this kind, the objectives of which have
+diameters of from 12 in. to 13 in., and which have been used for
+several years past in equatorial observations of all kinds. The Vienna
+Observatory has for the last two years been using an instrument of
+this kind whose objective has an aperture of 15 inches. Another
+equatorial of the same kind, of 16 in. aperture, is now in course of
+construction for the Nice Observatory, where it will be especially
+employed as a seeker of exceptional power--a role to which this kind
+of instrument lends itself admirably. The optical part of all these
+instruments was furnished by the Messrs. Henry, and the mechanical
+part by Mr. Gautier.
+
+The largest elbowed equatorial is, therefore, that of the Paris
+Observatory. Its optical power, moreover, corresponds perfectly to its
+huge dimensions. The experimental observations which have already been
+made with it fully justify the hopes that we had a right to found upon
+the professional skill of the eminent artists to whom we owe this
+colossal instrument. The images of the stars were given with the
+greatest sharpness, and it was possible to study the details of the
+surface of the moon and other planets, and several star clusters, in
+all their peculiarities, in the most remarkable manner.
+
+When it shall become possible to make use of this equatorial for
+celestial photography, there is no doubt that we shall obtain the most
+important results. As regards the moon, in particular, the
+photographing of which has already made so great progress, its direct
+image at the focus of the large 24 in. photographic objective will
+have a diameter of 11 in., and, being magnified, will be capable of
+giving images of more than 3 ft. in diameter.--_La Nature_.
+
+       *       *       *       *       *
+
+
+
+
+LILY OF THE VALLEY.
+
+
+There is no flower more truly and universally popular than the lily of
+the valley. What can be more delicious and refreshing than the scent
+of its fragrant flowers? What other plant can equal in spring the
+attractiveness of its pillars of pure white bells half hidden in their
+beautiful foliage? There are few gardens without a bed of lily of the
+valley, but too often the place chosen for it is some dark corner
+where nothing else would be expected to grow, but it is supposed as a
+matter of course that "it will do for a lily bed." The consequence is
+that although these lilies are very easy things to cultivate, as
+indeed they ought to be, seeing that they grow wild in the woods of
+this and other countries, yet one hears so often from those who take
+only a slight interest in practical gardening, "I have a lily bed, but
+I scarcely ever get any lilies." Wild lilies are hardly worth the
+trouble of gathering, they are so thin and poor; it is interesting to
+find a plant so beautiful and precious in the garden growing wild in
+the woods, but beyond that the flowers themselves are worth but very
+little. This at once tells us an evident fact about the lily of the
+valley, viz., that it does require cultivation. It is not a thing to
+be left alone in a dark and dreary corner to take care of itself
+anyhow year after year. People who treat it so deserve to be
+disappointed when in May they go to the lily bed and find plenty of
+leaves, but no flowers, or, if any, a few poor, weak attempts at
+producing blossoms, which ought to be so beautiful and fragrant.
+
+One great advantage of this lovely spring flower is that it can be so
+readily and easily forced. Gardeners in large places usually spend
+several pounds in the purchase of crowns and clumps of the lily of the
+valley, which they either import direct from foreign nurserymen or
+else procure from their own dealer in such things, who imports his
+lilies in large quantities from abroad. But we may well ask, Have
+foreign gardeners found out some great secret in the cultivation of
+this plant? Or is their climate more suitable for it? Or their soil
+adapted to growing it and getting it into splendid condition for
+forcing? It is impossible that the conditions for growing large and
+fine heads of this lily can be in any way better in Berlin or
+elsewhere than they are in our own land, unless greater heat in summer
+than we experience in England is necessary for ripening the growths in
+autumn.
+
+There is another question certainly as to varieties; one variety may
+be superior to another, but surely if so it is only on the principle
+of the survival of the fittest, that is to say, by carefully working
+on the finest forms only and propagating from them, a strong and
+vigorous stock may be the result, and this stock may be dignified with
+a special name. For my own part what I want is to have a great
+abundance of lily of the valley from February till the out-door season
+is over. To do this with imported clumps would, of course, be most
+costly, and far beyond what any person ought to spend on mere flowers.
+Though it must be remembered that it is an immense advantage to the
+parish priest to be able to take bright and sweet flowers to the
+bedside of the sick, or to gratify the weary spirit of a confirmed
+invalid, confined through all the lovely spring time to the narrow
+limits of a dull room, with the fragrant flowers of the lily of the
+valley. I determined, therefore, that I would have an abundance of
+early lilies, and that they should not be costly, but simply produced
+at about the same expense as any other flowers, and I have been very
+successful in accomplishing this by very simple means. First of all,
+it is necessary to have the means of forcing, that is to say the
+required heat, which in my case is obtained from an early vinery. I
+have seen lilies forced by pushing the clumps in under the material
+for making a hot bed for early cucumbers, the clumps being drawn out,
+of course, as soon as the flowers had made a good start. They have
+then to be carefully and very gradually exposed to full light, but
+often, although fine heads of bloom may be produced in this way, the
+leaves will be few and poor.
+
+My method is simply this: In the kitchen garden there is the old
+original bed of lilies of the valley in a corner certainly, but not a
+dark corner. This is the reservoir, as were, from whence the regular
+supply of heads for special cultivation is taken. This large bed is
+not neglected and left alone to take care of itself, but carefully
+manured with leaf mould and peat moss manure from the stable every
+year. Especially the vacant places made by taking out the heads for
+cultivation are thus filled up.
+
+Then under the east wall another piece of ground is laid out and
+divided into four plots. When I first began to prepare for forcing I
+waited four years, and had one plot planted with divided heads each
+year. Clumps are taken up from the reserve bed and then shaken out and
+the heads separated, each with its little bunch of fibrous roots. They
+are then carefully planted in one of the plots about 4 in. or 5 in.
+apart, the ground having previously been made as light and rich as
+possible with plenty of leaf mould. I think the best time for doing
+this is in autumn, after the leaves have turned yellow and have rotted
+away; but frequently the operation has been delayed till spring,
+without much difference in the result.
+
+Asparagus is usually transplanted in spring, and there is a wonderful
+affinity between the two plants, which, of course, belong to the same
+order. It was a long time to wait--four years--but I felt there was no
+use in being in too great a hurry, and every year the plants
+manifestly improved, and the buds swelled up nicely and looked more
+plump each winter when the leaves were gone. It must be remembered
+also that a nice crop of flowers could be gathered each year. When the
+fourth year came, the first plot was divided up into squares about 2
+ft. each way, and taken up before any hard frost or snow had made
+their appearance, and put away on the floor of an unused stable. From
+the stable they are removed as required in the squares to the vinery,
+where they grow beautifully, not sending up merely fine heads of bloom
+without a vestige of leaf, but growing as they would in spring out of
+doors with a mass of foliage, among which one has to search for the
+spikes of flower, so precious for all sorts of purposes at that early
+season of the year.
+
+The spikes produced in this way do not equal in thickness and
+substance of petal the flowers which come from more carefully prepared
+clumps imported from Berlin, but they are fine and strong, and above
+all most abundant. I can not only supply the house and small vases for
+the church, but also send away boxes of the flowers to friends at a
+distance, besides the many gifts which can be made to those who are
+ill or invalids. Few gifts at such a time are more acceptable than a
+fragrant nosegay of lily of the valley. In order to keep the supply of
+prepared roots ready year after year, a plot of ground has only to be
+planted each autumn, so that in the rotation of years it may be ready
+for forcing when its turn shall come.
+
+As the season advances, as every one knows who has attempted to force
+the lily of the valley, much less time is taken in bringing the
+flowers to perfection under precisely the same circumstances as those
+in which the first sods are forced. In February or earlier the buds
+are more unwilling to start; there seems to be a natural repugnance
+against being so soon forced out of the winter's sleep and rest. But
+when the flowers do come, they are nearly as fine and their leaves are
+quite as abundant in this way of forcing as from the pieces introduced
+much later into heat. It would be easy to preserve the squares after
+all the flowers are gathered, but I found that they would not, like
+strawberries, kindly furnish forth another crop later on in the year,
+and, therefore, mine are flung away; and I have often pitied the
+tender leaves in the frost and snow after their short sojourn in the
+hot climate of the vinery. But the reserve bed will always supply an
+ample quantity of fresh heads, and it is best to take the new plants
+for preparation in the kitchen garden from this reserve bed.
+
+This very simple method of forcing lilies of the valley is within the
+reach of any one who has even a small garden and a warm house, and
+these two things are becoming more and more common among us every
+day.--_A Gloucestershire Parson, in The Garden_.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12820.]
+
+
+
+
+REPORT ON INSECTS.
+
+THE ONION MAGGOT.
+
+_Phorbia ceparum_ (Meig.)
+
+
+Early in June a somewhat hairy fly, Fig. 9, may be seen flying about,
+and depositing its eggs on the leaves of the young onion plants, near
+the roots, Fig. 10.
+
+[Illustration: FIG. 9.]
+
+Dr. Fitch describes this fly as follows: "It has a considerable
+resemblance to the common house fly, though when the two are placed
+side by side, this is observed as being more slender in its form. The
+two sexes are readily distinguished from each other by the eyes, which
+in the males are close together, and so large as to occupy almost the
+whole surface of the head, while in the females they are widely
+separated from each other. These flies are of an ash gray color, with
+the head silvery, and a rusty black stripe between the eyes, forked at
+its hind end. And this species is particularly distinguished by having
+a row of black spots along the middle of the abdomen or hind body,
+which sometimes run into each other, and then forming a continuous
+stripe.
+
+"This row of spots is quite distinct in the male, but in the female is
+very faint, or is often wholly imperceptible. This fly measured 0.22
+to 0.25 inch in length, the females being usually rather larger than
+the males." The eggs are white, smooth, somewhat oval in outline, and
+about one twenty-fifth of an inch in length. Usually not more than
+half a dozen are laid on a single plant, and the young maggot burrows
+downward within the sheath, leaving a streak of pale green to indicate
+its path, and making its way into the root, devours all except the
+outer skin.
+
+[Illustration: FIG. 10.]
+
+The maggots reach their full growth in about two weeks, when they are
+about one-third of an inch long, white and glossy, tapering from the
+posterior end to the head, which is armed with a pair of black,
+hook-like jaws. The opposite end is cut off obliquely and has eight
+tooth-like projections around the edge, and a pair of small brown
+tubercles near the middle. Fig. 11 shows the eggs, larva, and pupa,
+natural size and enlarged.
+
+[Illustration: FIG. 11.]
+
+They usually leave the onions and transform to pupæ within the ground.
+The form of the pupa does not differ very much from the maggot, but
+the skin has hardened and changed to a chestnut brown color, and they
+remain in this stage about two weeks in the summer, when the perfect
+flies emerge. There are successive broods during the season, and the
+winter is passed in the pupa stage.
+
+The following remedies have been suggested:
+
+Scattering dry, unleached wood ashes over the plants as soon as they
+are up, while they are wet with dew, and continuing this as often as
+once a week through the month of June, is said to prevent the deposit
+of eggs on the plants.
+
+Planting the onions in a new place as remote as possible from where
+they were grown the previous year has been found useful, as the flies
+are not supposed to migrate very far.
+
+Pulverized gas lime scattered along between the rows has been useful
+in keeping the flies away.
+
+Watering with liquid from pig pens collected in a tank provided for
+the purpose, was found by Miss Ormerod to be a better preventive than
+the gas lime.
+
+When the onions have been attacked and show it by wilting and changing
+color, they should either be taken up with a trowel and burned, or
+else a little diluted carbolic acid, or kerosene oil, should be
+dropped on the infested plants to run down them and destroy the
+maggots in the roots and in the soil around them.
+
+Instead of sowing onion seed in rows, they should be grown in hills,
+so that the maggots, which are footless, cannot make their way from
+one hill to another.
+
+
+THE CABBAGE BUTTERFLY.
+
+_Pieris rapae_ (Linn.)
+
+
+In the New England States there are three broods of this insect in a
+year, according to Mr. Scudder, the butterflies being on the wing in
+May, July, and September; but as the time of the emergence varies, we
+see them on the wing continuously through the season.
+
+[Illustration: FIG. 12.]
+
+The expanded wings, Fig. 12, male, measure about two inches, are white
+above, with the base dusky. Both sexes have the apex black and a black
+spot a little beyond the middle, and the female, Fig. 13, has another
+spot below this. The under side of the fore wings is white, yellowish
+toward the apex, and with two black spots in both sexes corresponding
+to those on the upper side of the female. A little beyond the middle
+of the costa, on the hind wings, is an irregular black spot on the
+upper surface, while the under surface is pale lemon yellow without
+marks, but sprinkled more or less with dark atoms. The body is black
+above and white beneath.
+
+[Illustration: FIG. 13.]
+
+The caterpillars of this insect feed on the leaves of cabbage,
+cauliflower, turnip, mignonette, and some other plants.
+
+The female lays her eggs on the under side of the leaves of the food
+plants, generally, but sometimes on the upper sides or even on the
+leaf stalks. They are sugar loaf shaped, flattened at the base, and
+with the apex cut off square at the top, pale lemon yellow in color,
+about one twenty-fifth of an inch long and one fourth as wide, and
+have twelve longitudinal ribs with fine cross lines between them.
+
+The eggs hatch in about a week, and the young caterpillars, which are
+very pale yellow, first eat the shells from which they have escaped,
+and then spin a carpet of silk, upon which they remain except when
+feeding. They now eat small round holes through the leaves, but as
+they grow older change to a greenish color, with a pale yellow line
+along the back, and a row of small yellow spots along the sides, and
+eat their way down into the head of the cabbage.
+
+[Illustration: FIG. 14.]
+
+Having reached its full growth, the caterpillar, Fig. 14, a, which is
+about an inch in length, wanders off to some sheltered place, as under
+a board, fence rail, or even under the edge of clapboards on the side
+of a building, where it spins a button of silk, in which to secure its
+hind legs, then the loop of silk to support the forward part of the
+body.
+
+It now casts its skin, changing to a chrysalis, Fig. 14, b, about
+three-fourths of an inch in length, quite rough and uneven, with
+projecting ridges and angular points on the back, and the head is
+prolonged into a tapering horn. In color they are very variable, some
+are pale green, others are flesh colored or pale ashy gray, and
+sprinkled with numerous black dots. The winter is passed in the
+chrysalis stage.
+
+After the caterpillar changes to a chrysalis, their minute parasites
+frequently bore through the outside and deposit their eggs within.
+These hatch before the time for the butterflies to emerge, and feeding
+on the contents, destroy the life of the chrysalis.
+
+Birds and spiders are of great service in destroying these insects.
+
+The pupæ should be collected and burned if the abdomen is flexible;
+but if the joints of the abdomen are stiff and cannot be easily moved,
+they should be left, as they contain parasites.
+
+Several applications of poisons have been used, the best results being
+obtained from the use of pyrethrum as a powder blown on to the plants
+by a hand bellows, during the hottest part of the day, in the
+proportion of one part to four or five of flour.
+
+As the eggs are laid at different times, any application, to be
+thoroughly tested, must be repeated several times.
+
+
+THE APPLE TREE TENT CATERPILLAR.
+
+_Clisiocampa Americana_ (Harr.)
+
+
+Large, white, silken web-like tents, Fig. 15, are noticed by the
+roadsides, in the early summer, on wild cherry trees, and also on
+fruit trees in orchards, containing numerous caterpillars of a
+blackish color, with fine gray hairs scattered over the body.
+
+This well known pest has been very abundant throughout the State for
+several years past, and the trees in many neglected orchards have been
+greatly injured by it, some being entirely stripped of their leaves.
+The trees in these orchards and the neglected ones by the roadsides
+form excellent breeding places for this insect, and such as are of
+little of no value should be destroyed. If this were well done, and
+all fruit growers in any given region were to destroy all the tents on
+their trees, even for a single season, the work of holding them in
+check or destroying them in the following year would be comparatively
+light.
+
+[Illustration: FIG. 15.]
+
+The moths, Fig. 16, appear in great numbers in July, their wings
+measuring, when expanded, from one and a quarter to one and a half
+inches or more. They are of a reddish brown color, the fore wings
+being tinged with gray on the base and middle, and crossed by two
+oblique whitish stripes.
+
+[Illustration: FIG. 16.]
+
+The females lay their eggs, about three hundred in number, in a belt,
+Fig. 15, c, around the twigs of apple, cherry, and a few other trees,
+the belt being covered by a thick coating of glutinous matter, which
+probably serves as a protection against the cold weather during
+winter.
+
+The following spring, when the buds begin to swell, the egg hatch and
+the young caterpillar seek some fork of a branch, where they rest side
+by side. They are about one-tenth of an inch long, of a blackish
+color, with numerous fine gray hairs on the body. They feed on the
+young and tender leaves, eating on an average two apiece each day.
+Therefore the young of one pair of moths would consume from ten to
+twelve thousand leaves; and it is not uncommon to see from six to
+eight nests or tents on a single tree, from which no less than
+seventy-five thousand leaves would be destroyed--a drain no tree can
+long endure.
+
+As the caterpillars grow, a new and much larger skin is formed
+underneath the old one, which splits along the back and is cast off.
+When fully grown, Fig. 15, a and b, which is in about thirty-five to
+forty days after emerging from the eggs, they are about two inches
+long, with a black head and body, with numerous yellowish hairs on the
+surface, with a white stripe along the middle of the back, and minute
+whitish or yellowish streaks, which are broken and irregular along the
+sides; and there is also a row of transverse, small, pale blue spots
+along each side of the back.
+
+As they move about they form a continuous thread of silk from a fleshy
+tube on the lower side of the mouth, which is connected with the
+silk-producing glands in the interior of the body, and by means of
+this thread they appear to find their way back from the feeding
+grounds. It is also by the combined efforts of all the young from one
+belt of eggs that the tents are formed.
+
+These caterpillars do not feed during damp, cold weather, but take two
+meals a day when it is pleasant.
+
+After reaching their full growth, they leave their tents and scatter
+in all directions, seeking for some protected place where each one
+spins its spindle-shaped cocoon of whitish silk intermingled with
+sulphur colored powder, Fig. 15, d. They remain in these cocoons,
+where they have changed to pupæ, from twenty to twenty-five days,
+after which the moths emerge, pair, and the females lay their eggs for
+another brood.
+
+Several remedies have been suggested, a few of which are given below.
+Search the trees carefully, when they are bare, for clusters of eggs;
+and, when found, cut off the twigs to which they are attached, and
+burn them.
+
+As soon as any tents are observed in the orchard they should be
+destroyed, which may be readily and effectually done by climbing the
+trees, and with the hand protected by a mitten or glove, seize the
+tent and crush it with its entire contents; also swab them down with
+strong soapsuds or other substances; or tear them down with a rounded
+bottle brush.
+
+Burning with a torch not only destroys the caterpillars but injures
+the trees.
+
+It should be observed, however, since the caterpillars, are quite
+regular in taking their meals, in the middle of the forenoon and
+afternoon, that they should be destroyed only in the morning or
+evening, when all are in the tent.
+
+Another remedy is to shower the trees with Paris green in water, in
+the proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE FOREST TENT CATERPILLAR.
+
+_Clisiocampa disstria_ (Hübner.)
+
+
+This species, commonly known as the forest tent caterpillar, closely
+resembles the apple tree tent caterpillar, but does not construct a
+visible tent. It feeds on various species of forest trees, such as
+oak, ash, walnut, hickory, etc., besides being very injurious to apple
+and other fruit trees. The moth, Fig. 17, b, expands an inch and a
+half or more. The general color is brownish yellow, and on the fore
+wings are two oblique brown lines, the space between them being darker
+than the rest of the wing. The eggs, Fig. 17, c and d, which are about
+one twenty fifth of an inch long and one fortieth wide, are arranged,
+three or four hundred in a cluster, around the twigs of the trees,
+Fig. 17, a. These clusters are uniform in diameter and cut off
+squarely at the ends. The eggs are white, and are firmly fastened to
+the twigs and to each other, by a brown substance, like varnish, which
+dries, leaving the eggs with a brownish covering.
+
+[Illustration: FIG. 17.]
+
+The eggs hatch about the time the buds burst, or before, and the young
+caterpillars go for some time without food, but they are hardy and
+have been known to live three weeks with nothing to eat, although the
+weather was very cold.
+
+[Illustration: FIG. 18.]
+
+As soon as hatched they spin a silken thread wherever they go, and
+when older wander about in search for food. The caterpillars are about
+one and a half inches long when fully grown, Fig. 18. The general
+color is pale blue, tinged with greenish low down on the sides, and
+everywhere sprinkled with black dots or points, while along the middle
+of the back is a row of white spots each side of which is an orange
+yellow stripe, and a pale, cream yellow stripe below that. These
+stripes and spots are margined with black. Each segment has two
+elevated black points on the back, from each of which arise four or
+more coarse black hairs. The back is clothed with whitish hairs, the
+head is dark bluish freckled with black dots, and clothed with black
+and fox-colored hairs, and the legs are black, clothed with whitish
+hairs.
+
+At this stage the caterpillars may be seen wandering about on fences,
+trees, and along the roads in search of a suitable place to spin their
+cocoons, which are creamy white, and look very much like those of the
+common tent caterpillar, except that they are more loosely
+constructed.
+
+Within the cocoons, in two or three days they transform to pupæ of a
+reddish brown color, densely clothed with short pale yellowish hairs.
+The moths appear in two or three weeks, soon lay their eggs and then
+die. The insects are not abundant many years in succession, as their
+enemies, the parasites, increase and check them.
+
+Many methods have been suggested for their destruction, but the most
+available and economical are to remove the clusters of eggs whenever
+found, and burn them, and to shower the trees with Paris green in the
+proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE STALK BORER.
+
+_Gortyna nitela_ (Gruen.)
+
+
+The perfect moth, Fig. 19, 1, expands from one to one and a half
+inches. The fore wings are a mouse gray color, tinged with lilac and
+sprinkled with fine yellow dots, and distinguished mainly by a white
+band extending across the outer part. The moths hibernate in the
+perfect state, and in April or May deposit their eggs singly on the
+outside of the plant upon which the young are to feed. As soon as the
+eggs hatch, which is in about a month, the young larvæ, or
+caterpillars, gnaw their way from the outside into the pith.
+
+[Illustration: FIG. 19.]
+
+The plant does not show any sign of decay until the caterpillar is
+fully grown, when it dies. The caterpillar, Fig. 19, 2, is about one
+and one-fourth inches long, of a reddish brown color, with whitish
+stripes along the body. The stripes on the sides are not continuous,
+and the shading of the body varies, being darker on the anterior than
+on the posterior portion. When fully grown, Fig. 20, the color is
+lighter and the stripes are broader. At this stage of life it burrows
+into the ground just beneath the surface, and changes into the pupa
+state. The pupa is three-fourths of an inch long, and of a mahogany
+brown color. The perfect moth appears about the first of September,
+and there is only one brood in a season.
+
+[Illustration: FIG. 20.]
+
+The caterpillars feed in the stalks of corn, tomatoes, potatoes,
+dahlias, asters, and also in young currant bushes, besides feeding on
+many species of weeds. By a close inspection of the plants about the
+beginning of July, the spot where the borer entered, which is
+generally quite a distance from the ground, may be detected, and the
+caterpillar cut out without injury to the plant. This plan is
+impracticable for an extensive crop, but by destroying the borers
+found in the vines that wilt suddenly, one can lessen the number
+another year.
+
+
+THE PYRAMIDAL GRAPEVINE CATERPILLAR.
+
+_Pyrophila pyramidoides_ (Guen.)
+
+
+This caterpillar, Fig. 21, is generally found on grapevines early in
+June, but also feeds on apple, plum, raspberry, maple, poplar, etc. It
+is about an inch and a half in length, with the body tapering toward
+the head; of a whitish green color, darker on the sides; with a
+longitudinal white stripe on the back, broader on the last segments.
+Low down on each side is a bright yellow stripe, between this and the
+one on the back is another less distinct, and the under surface of the
+body is pale green.
+
+[Illustration: FIG. 21.]
+
+The caterpillar is fully grown about the middle or last of June, when
+it descends to the ground, draws together some of the fallen leaves,
+and makes a cocoon, in which it soon changes to a mahogany brown pupa.
+
+[Illustration: FIG. 22.]
+
+In the latter part of July the perfect moth, Fig. 22, emerges,
+measuring, when its wings are expanded, about one and three-fourths
+inches; the fore wings are dark brown shaded with lighter, with dots
+and wavy lines of dull white. The hind wings are reddish, or of a
+bright copper color, shading to brown on the outer angle of the front
+edge of the wing, and paler toward the hinder and inner angle.
+
+The under surface of the wings is lighter than the upper, and the body
+is dark brown, with its posterior portion banded with lines of a paler
+hue.
+
+This pest may be destroyed by hand picking, or by jarring the trees or
+vines on which they are feeding, when they will fall to the ground and
+may be crushed or burned.
+
+
+THE GRAPE BERRY MOTH.
+
+_Eudemis botrana_ (S.V.)
+
+
+The moths emerge and fly early in June, and are quite small,
+measuring, when the wings are expanded, only two-fifths of an inch,
+Fig. 23, a, enlarged. The fore wings are purplish or slate brown from
+the base to the middle, the outer half being irregularly marked with
+dark and light brown.
+
+[Illustration: FIG. 23.]
+
+These insects are two-brooded and the first brood feeds not only on
+the leaves of the grape, but on tulip, sassafras, vernonia and
+raspberry. The caterpillars of the second brood emerge when the grapes
+are nearly grown, and bore in them a winding channel to the pulp,
+continuing to eat the interior of the berry till the pulp is all
+consumed, Fig. 23, d, when, if not full grown, they draw one or two
+other berries close to the first and eat the inside of those.
+
+The mature caterpillar, Fig. 23, b, measures about half an inch in
+length, is dull greenish, with head and thoracic shield somewhat
+darker; the internal organs give the body a reddish tinge. It then
+leaves the grape and forms its cocoon by cutting out a piece of a
+leaf, leaving it hinged on one side; then rolling the cut end over,
+fastens it to the leaf, thus making for itself a cocoon in which to
+pupate. The pupa is dark reddish brown.
+
+The second generation passes the winter in the pupa state, attached to
+leaves which fall to the ground; therefore, if all the dead and dried
+leaves be gathered in the fall and burned, also all the decayed fruit,
+a great many of these insects would be destroyed. As the caterpillars
+feed inside of the berry, no spraying of the vines with poisons would
+reach them. The caterpillar makes a discolored spot where it enters
+the berry, Fig. 23, c. Therefore the infested fruit may be easily
+detected and destroyed.
+
+There is a small parasite that attacks this insect and helps to keep
+it in check. The insect has been known in Europe over a hundred years.
+It is not certain when it was introduced into America, but it is now
+found from Canada to the Gulf of Mexico, and from the Atlantic to the
+Pacific Ocean.
+
+
+THE CODLING MOTH.
+
+_Carpocapsa pomonella_ (Linn.)
+
+
+This well known insect has a world-wide reputation, and is now found
+wherever apples are raised.
+
+[Illustration: FIG. 24.]
+
+The moths are on the wing about the time the young apples are
+beginning to set, and the female lays a single egg in the blossom end
+of each apple. The fore wings of the moths when expanded, Fig. 24, g
+(f, with the wings closed), measure about half an inch across, and are
+marked with alternate wavy, transverse streaks of ashy gray and brown,
+and have on the inner hind angle a large tawny brown, horseshoe shaped
+spot, streaked with light bronze or copper color. The hind wings and
+abdomen are light brown with a luster of satin.
+
+Each female lays about fifty eggs, which are minute, flattened,
+scale-like bodies of a yellowish color. In about a week the eggs hatch
+and the tiny caterpillar begins to eat through the apple to the core,
+Fig. 24, a, pushing its castings out through the hole where it
+entered, Fig. 24, b. Oftentimes these are in sight on the outside in a
+dark colored mass, thus making wormy apples plainly seen at quite a
+distance.
+
+The caterpillar is about two-fifths of an inch in length, of a glossy,
+pale yellowish white color, with a light brown head. The skin is
+transparent and the internal organs give to it a reddish tinge.
+
+When mature the caterpillars, Fig. 24, e, top of head and second
+segment, h, emerge from the apples and seek some sheltered place, such
+as crevices of bark, or corners of the boxes or barrels in which the
+fruit is stored, where they spin a tough whitish cocoon, Fig. 24, i,
+in which they remain unchanged all winter, and transform to pupæ, Fig.
+24, d, the next spring, the perfect moths emerging in time to lay
+their eggs in the new crop of apples.
+
+One good remedy is to gather all the fallen apples, and feed them to
+hogs; another is to let swine and sheep run in the orchard, and eat
+the infested fruit.
+
+It has been recommended to place bands of cloth or hay around the
+trunks of the trees for the caterpillars to spin their cocoons
+beneath, and to remove them at the proper time, and put them in
+scalding water to destroy the worms.
+
+By far the most successful method as yet adopted is to shower the
+apple trees with Paris green in water, one pound to one hundred and
+fifty gallons of water, when the apples are about the size of peas,
+and again in about a week.
+
+
+THE CABBAGE LEAF MINER.
+
+_Plutella cruciferarum_ (Zell.)
+
+
+The cabbage leaf miner is not a native of this country, but was
+imported from Europe.
+
+[Illustration: FIG. 25.]
+
+The perfect moth, Fig. 25, f, with the wings expanded (h, with the
+wings closed, g, a dark variety), measures three-quarters of an inch.
+The fore wings are ashy gray, and on the hinder margin is a white or
+yellowish white stripe having three points extending into the gray,
+thus forming, when the wings are closed, three diamond-shaped white
+spots. Generally there is a dark brown stripe between the white and
+the gray. There are also black dots scattered about on the anterior
+part of these wings.
+
+The hind wings are leaden brown, and the under side of all the wings
+is leaden brown, glossy, and without any dots.
+
+The antennæ are whitish with dark rings, and the abdomen white. There
+are two broods of this insect in this region, the moths of the first
+appearing in May, and those of the second in August. They hibernate in
+the pupa stage.
+
+The caterpillars, Fig. 25, a (b, the top and c, the side of a
+segment), appear in June or July and September; they are small and
+cylindrical, tapering at both ends, pale green, and about one-fourth
+of an inch long. The head has a yellowish tinge, and there are several
+dark stiff hairs scattered over the body.
+
+When ready to transform, this caterpillar spins a delicate gauze-like
+cocoon, Fig. 25, e, made of white, silken threads, on the under side
+of a cabbage leaf. The pupa, Fig. 25, d, and i, the end of a pupa, is
+commonly white, sometimes shaded with reddish brown, and can be
+distinctly seen through the silken case.
+
+The first brood is more injurious than the second, as it feeds on the
+young cabbage leaves before the head is formed, and this must surely
+stunt the growth and make weak, sickly plants; while the second brood
+feeds only on the outside leaves. The caterpillars are very active,
+wriggling violently when disturbed, and falling by a white silken
+thread.
+
+Hot dry weather is favorable to them and enables them to multiply
+rapidly. Advantage has been taken of this fact, and spraying the
+plants thoroughly with water is strongly recommended. Prof. Riley
+states that the insects are very readily destroyed by pyrethrum. There
+are two species of spiders and a species of ichneumon fly that destroy
+them.
+
+
+THE GARTERED PLUME MOTH.
+
+_Oxyptilus periscelidactylus_ (Fitch.)
+
+
+The caterpillars of this species draw together the young grape leaves,
+Fig. 26, a, in the spring, with fine silken threads, and feed on the
+inside, thus doing much damage in proportion to their size. These
+caterpillars, Fig. 26, a, and e, a segment greatly enlarged, are full
+grown in about two weeks, when they are about one-fourth of an inch
+long, pale green with whitish hairs arising from a transverse row of
+warts on each segment.
+
+Early in June they transform to pupæ, Fig. 26, b, which are pale green
+at first and change to dark brown. The surface is rough and the head
+is cut off obliquely, while on the upper side near the middle are two
+sharp pointed horns, Fig. 26, c. They remain in this stage from a week
+to ten days, when the moths emerge.
+
+[Illustration: FIG. 26.]
+
+The moths, Fig. 26, d, belong to the family commonly known as plume
+moths or feather wings (Pterophoridæ), from having their wings divided
+into feather-like lobes. When the wings are expanded they measure
+about seven-tenths of an inch across. They are yellowish brown with a
+metallic luster, and have several dull whitish streaks and spots. The
+fore wings are split down the middle about half way to their base, the
+posterior half having a notch in the outer margin. The body is
+somewhat darker than the wings.
+
+It is not known positively in what stage the winter is passed, but it
+is supposed to be the perfect, or imago stage. The unnatural grouping
+and spinning of the leaves together leads to their detection, and they
+can be easily destroyed by hand picking and then crushing or burning
+them.
+
+       *       *       *       *       *
+
+
+
+
+THE BREEDS OF DOGS.
+
+
+The dog exhibitions that have annually taken place for the last eight
+years at Paris and in the principal cities of France have shown how
+numerous and varied the breeds of dogs now are. It is estimated that
+there are at present, in Europe, about a hundred very distinct and
+very fine breeds (that is to say, such as reproduce their kind with
+constant characters), without counting a host of sub-breeds or
+varieties that a number of breeders are trying to fix.
+
+Most of the breeds of dogs, especially those of modern creation, are
+the work of man, and have been obtained by intercrossing older breeds
+and discarding all the animals that departed from the type sought. But
+many of these breeds are also the result of accident, or rather of
+modifications of certain parts of the organism--of a sort of rachitic
+or teratological degeneration which has become hereditary and has been
+due to domestication; for it is proved that the dog is the most
+anciently domesticated animal, and that its submission to man dates
+back to more than five thousand years. Such is the origin of the
+breeds of terriers, bulldogs, and all of the small house dogs.
+
+Man has often, designedly or undesignedly, aided in the production of
+breeds of this last category by submitting the dog to a regimen
+contrary to nature, or setting to work to reproduce an animal born
+monstrous, either for curiosity or for interest. As well known, the
+accidental characters and the spontaneous modifications which work no
+injury to the essential functions of life became easily hereditary,
+and the same is the case with certain artificial modifications pursued
+for a long series of generations.
+
+It was the opinion of Buffon that the breeds of dogs, which were
+already numerous in his time, were all derived from a single type,
+which, according to him, was the shepherd's dog. Other scientists have
+insisted that the dog descended from the wolf, and others from the
+jackal. At the present time, it is rightly admitted that several
+species of wild dogs have concurred in the formation of the different
+breeds of dogs as we now have them.
+
+In the lacustrine habitations of the stone age in Sweden, and in the
+_kjoekkenmoedding_ (kitchen remains) of Denmark, of the same epoch, we
+find the remains of a dog, which, according to Rutymeyer, belongs to a
+breed which is constant up to its least details, and which is of a
+light and elegant conformation, of medium size, with a spacious and
+rounded cranium and a short, blunt muzzle, and a medium sized jaw, the
+teeth of which form a regular series.
+
+This dog, which has been named by geologists _Canis palustris_, fully
+resembles in size, slenderness of the limbs, and weakness of the
+muscular insertions, the spaniel, the brach hound, or the griffon.
+
+This dog of the stone age is entirely distinct from the wolf and
+jackal, of which some regard the domestic dog as a descendant, and as
+it has appeared in Denmark as well as in Sweden, there is no doubt
+that this species, peculiar to Europe, was subjugated by man and used
+by him, in the first place, for hunting, and later on for guarding
+houses and cattle. Later still, in the age of metals, we observe the
+appearance, both in Denmark and Sweden, of larger and stronger breeds
+of dogs, having in their jaws the character of mastiffs, and probably
+introduced by the first emigrants from Asia.
+
+There are, moreover, historic proofs that the dogs of the strongest
+breeds are indigenous to Asia, where we still find the dog of Thibet,
+the most colossal of all; in fact, in Pliny we read the following
+narrative: Alexander the Great received from a king of Asia a dog of
+huge size. He wished to pit it against bears and wild boars, but the
+dog remained undisturbed and did not even rise, and Alexander had it
+killed. On hearing of this, the royal donor sent a second dog like
+the first, along with word that these dogs did not fight so weak
+animals, but rather the lion and the elephant, and that he had only
+two of such individuals, and in case that Alexander had this one
+killed, too, he would no longer find his equal. Alexander matched this
+dog with a lion and then with an elephant, and he killed them both.
+Alexander was so afflicted at the premature death of the first dog,
+that he built a city and temples in honor of the animal.
+
+Did the mountainous province of Epirus called Molossia, in ancient
+Greece, give its name to the _molossi_ that it produced, or did these
+large dogs give their name to the country? At all events, we know that
+it was from Epirus that the Romans obtained the molossi which fought
+wild animals in the circuses, and that from Rome they were introduced
+into the British islands and have became the present mastiffs.
+
+Although our hunting and shepherd's dogs have a European and the
+mastiffs an Asiatic ancestry, the ancestry of the harriers is African,
+and especially Egyptian; in fact, in Upper Egypt we find a sort of
+large white jackal (_Simenia simensis_) with the form of a harrier,
+and which Paul Gervais regarded with some reason as the progenitor of
+the domestic harrier, and a comparison of their skulls lends support
+to this opinion.
+
+A study of the most ancient monuments of the Pharaohs shows that the
+ancient Egyptians already had at least five breeds of dogs: two very
+slim watch dogs, much resembling the harrier, a genuine harrier, a
+species of brach hound and a sort of terrier with short and straight
+legs. All these dogs had erect ears, except the brach, in which these
+organs were pendent, and this proves that the animal had already
+undergone the effects of domestication to a greater degree than the
+others. The harrier of the time of the Pharaohs still exists in great
+numbers in Kordofan, according to Brehm.
+
+Upon the whole, we here have, then, at least three stocks of very
+distinct dogs: 1, a hunting or shepherd's dog, of European origin; 2,
+a mastiff, typical of the large breed of dogs indigenous to Asia; and
+3, a harrier, indigenous to Africa.
+
+We shall not follow the effects of the combination of these three
+types through the ages, and the formation of the different breeds; for
+that we shall refer our readers to a complete work upon which we have
+been laboring for some years, and two parts of which have already
+appeared.[1]
+
+[Footnote 1: Les Races des Chiens, in La Bibliotheque de l'Eleveur.]
+
+We shall rapidly pass in review the different breeds of dogs that one
+may chance to meet with in our dog shows, beginning with the largest.
+It is again in mountainous countries that the largest dogs are raised,
+and the character common to all of these is a very thick coat. The
+largest of all, according to travelers, is the Thibetan dog. Buffon
+tells of having seen one which, when seated, was five feet in height.
+One brought back by the Prince of Wales from his voyage to the Indies
+was taller in stature, stronger and more stocky than a large mastiff,
+from which it differed, moreover, in its long and somewhat coarse
+hair, which was black on the back and russet beneath, the thighs and
+the tail being clothed with very long and silky hair.
+
+In France, we have a beautiful mountain dog--the dog of the
+Pyrenees--which is from 32 to 34 inches in height at the shoulders,
+and has a very thick white coat, spotted above with pale yellow or
+grayish fox color. It is very powerful, and is capable of
+successfully defending property or flocks against bears and wolves.
+
+The Alpine dog is the type of the mountain dog. It is of the same size
+as the dog of the Pyrenees, and differs therefrom especially in its
+coloring. It is white beneath, with a wide patch of orange red
+covering the back and rump. The head and ears are of the same color,
+with the addition of black on the edges; but the muzzle is white, and
+a stripe of the same color advances upon the forehead nearly up to the
+nape of the neck. The neck also is entirely white. There are two
+varieties of the Alpine or St. Bernard dog, one having long hair and
+the other shorter and very thick hair. We give in Fig. 1 a portrait of
+Cano, a large St. Bernard belonging to Mr. Gaston Leonnard.
+
+[Illustration: FIG. 1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.]
+
+Although this breed originated at the celebrated convent of St.
+Bernard, it no longer exists there in a state of purity, and in order
+to find fine types of it we have to go to special breeders of
+Switzerland and England. The famous Plinnlimon, which was bought for
+$5,000 by an American two or three years ago, and about which there
+was much talk in the papers, even the political ones, was born and
+reared in England. It appears that it is necessary, too, to reduce the
+number of life-saving acts that it is said are daily performed by the
+St. Bernard dogs. This is no longer but a legend. There was, it is
+true, a St. Bernard named Barry, now exhibited in a stuffed state in
+the Berne Museum, which accomplished wonders in the way of saving
+life, but this was an exception, and the reputation of this animal has
+extended to all others of its kind. These latter are simply watch dogs
+kept by the monks for their own safety, and which do not go at all by
+themselves alone to search for travelers that have lost their way in
+the snow.
+
+The Newfoundland dog, which differs from the preceding in its wholly
+black or black and white coat, was, it appears, also of mountain
+origin. According to certain authors, it is indigenous to Norway, and
+was carried to Newfoundland by the Norwegian explorers who discovered
+the island. Adapted to their new existence, they have become excellent
+water dogs, good swimmers, and better life savers by far than the
+majority of their congeners.
+
+Is it from descending to the plain that the mountain dogs have lost
+their long hair and have become short haired dogs like the English dog
+or mastiff and the German or large Danish dogs? It is very probable.
+At all events, it is by this character of having short hair that
+mastiffs are distinguished from the mountain dogs. Again, the large
+breed of dogs are distinguished from each other by the following
+characters: The mastiff is not very high at the shoulders (30 inches),
+but he is very heavy and thick set, with powerful limbs, large head,
+short and wide muzzle and of a yellowish or café-au-lait color
+accompanying a black face; that is to say, the ears, the circumference
+of the eyes and the muzzle are of a very dark color. The German or
+large Danish dogs constitute but one breed, but of three varieties,
+according to the coat: (1) those whose coat is of a uniform color, say
+a slaty gray or isobelline of varying depth, without any white spots;
+(2) those having a fawn colored coat striped transversely with black
+like the zebra, but much less distinctly; (3) those having a spotted
+coat, that is to say, a coat with a white ground strewed with
+irregular black spots of varying size. These, like those of the first
+variety are generally small-eyed. Whatever be the variety to which
+they belong, the German or large Danish dogs are slimmer than, and not
+so heavy as, the mastiffs. Some, even, are so light that it might be
+supposed that they had some heavier blood in their veins. They have
+also a longer muzzle, although square, and are quicker in gait and
+motions.
+
+The largest dogs are to be met with in this breed, and the beautiful
+Danish dog belonging to Prof. Charcot (Fig. 2) is certainly the
+largest dog in France and perhaps in Europe. It measures 36 inches at
+the shoulders and has an osseous and muscular development perfectly in
+keeping with its large stature, and at the same time has admirable
+proportions and lightness, and its motions are comparable to those of
+the finest horse.
+
+[Illustration: FIG. 2--DR. CHARCOT'S LARGE DANISH DOG.]
+
+Among the English dogs or mastiffs, we very frequently meet with
+individuals in which the upper incisors and canines are placed back of
+the corresponding ones in the lower jaw, this being due to a slight
+shortening of the bones of the upper jaw, not visible externally. This
+is the first degree of an artist of teratological development, which,
+since the middle ages, has become very marked in certain subjects, and
+has given rise to a variety in which this defect has become
+hereditary. Such is the origin of the breed of bulldogs. The latter
+were originally as large as the mastiffs. Carried to Spain under
+Philip II., they have there preserved their primitive characters, but
+the bulldogs remaining in England have continued to degenerate, so
+that now the largest are scarcely half the size of the Spanish
+bulldog, and the small ones attain hardly the size of the pug,
+although they preserve considerable width of chest and muscular
+strength.
+
+
+POINTERS.
+
+Man hunted for ages with dogs that he united in a pack; but these
+packs were of a very heterogeneous composition, since they included
+strong dogs, light dogs very swift of foot, shepherds' dogs, and
+others noted for acuteness of scent, and even mongrels due to a
+crossing with the wolf. It is from the promiscuousness of all these
+breeds that has arisen our ordinary modern dog.
+
+The pointer is of relatively recent creation, and is due to the
+falconers. In our western countries, falconry dates from the fourth
+and fifth centuries, as is proved by the capitularies of Dagobert.
+This art, therefore, was not brought to us from the East by the
+crusaders in the twelfth and thirteenth centuries, as stated by Le
+Maout in his Natural History of Birds.
+
+The falconer soon saw the necessity of having a dog of nice scent
+having for its role the finding or hunting up of game without pursuing
+it, in order to permit the falcons themselves to enter into the sport.
+This animal was called the bird dog, and was regarded as coming from
+various countries, especially from Spain, whence the name of spaniel
+that a breed of pointers has preserved. It is quite curious to find
+that for three or four centuries back there have been no spaniels in
+Spain. From Italy also and from southern climes comes what is called
+the _bracco_, whence doubtless is derived the French name _braque_ and
+English brach. Finally the _agasse_ of the Bretons was certainly also
+one of the progenitors of our present pointers. It was, says Oppian, a
+breed of small and very courageous dogs, with long hair, provided with
+strong claws and jaws, that followed hares on the sly under shelter of
+vine-stocks and reeds and sportively brought them back to their
+masters after they had captured them. We have certainly here the
+source of our barbets and griffons.
+
+Finally the net hunters of the middle ages also contributed much to
+the creation of the pointer, for it is to them that we owe the setter.
+It is erroneously, in fact, that certain authors have attributed the
+creation of this dog to hunters with the arquebuse, since this weapon
+did not begin to be utilized in hunting until the sixteenth century.
+Gaston Phoebus, who died in 1391, shows, in his remarkable work, that
+the net hunters made use of Spanish setters and that it was they who
+created the true pointer--the animal that fascinates game by its gaze.
+By the same pull of their draw net they enveloped in its meshes both
+the setter and the prey that it held spellbound.
+
+Upon the whole, we see that at the end of the middle ages there
+existed three types of pointers: spaniels, brachs and very hairy dogs,
+that Charles Estienne, in his Maison Rustique, of the sixteenth
+century, calls barbets. It is again with these three types that are
+connected all the present pointers, which we are going to pass rapidly
+in review.
+
+_The Brach hounds_.--To-day we reserve the name of brachs for all
+pointers with short hair. The type of the old brach still exists in
+Italy, Spain, the south of France and in Germany. It is characterized
+by its large size, its robust form, its large head, its long, flat
+ears, its square muzzle separated from the forehead by a deep
+depression, its large nose, often double (that is to say, with
+nostrils separated by a deep vertical groove), its pendent lips, its
+thick neck, its long and strong paws provided with dew claws, both on
+the fore and the hind feet, and its short hair, which is usually white
+and marked with brown or orange-yellow spots. The old brach breed has
+been modified by the breeders of different countries, either by
+hygiene or by crossing with ordinary dogs, according to the manner of
+hunting, according to taste, and even according to fashion. Thus in
+England, where "time is money" reigns in every thing and where they
+like to hunt quickly and not leisurely, the brach has been rendered
+lighter and swifter of foot and has become the pointer. In France,
+while it has lost a little in size and weight, it has preserved its
+moderate gait and has continued to hunt near its master, "under the
+gun," as they say. The same is the case in Spain, Italy and Germany
+even. In France there are several varieties or sub-breeds of brach
+hounds. The old French brach, which is nothing more than the old type,
+preserved especially in the south, where it is called the Charles the
+Tenth brach, is about twenty-four inches in height, and has a white
+and a maroon coat, which is somewhat coarse. It often has a cleft nose
+and dew-claws on all the feet. The brach of the south scarcely differs
+from the preceding except in color. Its coat has a white ground
+covered with pale orange blotches and spots of the same color. The St.
+Germain brach is finer bred, and appears to be a pointer introduced
+into France in the time of Charles X. It has a very fine skin, very
+fine hair of a white and orange color. The Bourbon brach has the
+characters of the old French brach, with a white coat marked here and
+there with large brown blotches, and the white ground spotted with the
+same color; but what particularly characterizes this dog is that it is
+born with a stumpy tail, as if three-quarters of it had been chopped
+off. The Dupuy brach is slender and has a narrow muzzle, as if it had
+some harrier blood in its veins. It is white, with large dark maroon
+blotches. The Auvergne brach resembles the southern brach, but has a
+white and black coat spotted with black upon white. The pointer, or
+English brach (Fig. 3), descends from the old Spanish brach, but has
+been improved and rendered lighter and much swifter of foot by the
+introduction of the blood of the foxhound into its veins, according to
+the English cynegetic authors themselves. The old pointer was of a
+white and orange color, and was indistinguishable from our St.
+Germain. The pointer now fancied is white and maroon and has a
+stronger frame than the pointer of twenty years ago. The Italian
+brachs are heavy, with lighter varieties, usually white and orange
+color, more rarely _roan_, and provided with dew-claws, this being a
+sign of purity of breed according to Italian fanciers. The German
+brachs are of the type of the old brach, with a stiff white and
+maroon coat, the latter color being so extensively distributed in
+spots on the white as to make the coat very dark.
+
+[Illustration: FIG 3.--POINTER.]
+
+_Spaniels_.--The old type of spaniel has nearly disappeared, yet we
+still find a few families of it in France, especially in Picardy and
+perhaps in a few remote parts of Germany. The old spaniel was of the
+same build as the brach, and differed from it in that the head, while
+being short-haired, was provided with ears clothed with long, wavy
+hair. The same kind of hair also clothed the whole body up to the
+tail, where it constituted a beautiful tuft. The Picard spaniel is a
+little lighter than the old spaniel. It has large maroon blotches upon
+a white ground thickly spotted with maroon, with a touch of flame
+color on the cheeks, over the eyes, and on the legs. The Pont-Andemer
+spaniel is a Norman variety, with very curly hair, almost entirely
+maroon colored, the white parts thickly spotted with a little color as
+in the Picard variety, and a characteristic forelock on the top of the
+head.
+
+[Illustration: FIG 4.--ENGLISH SETTERS.]
+
+In England, the spaniel has given rise to several varieties. In the
+first place there are several sub-breeds of setters, viz.: The English
+setter, still called laverack, which has large black or orange-colored
+blotches on the head, the rest of the body being entirely white, with
+numerous spots of the same color as the markings on the head (Fig. 4);
+the Irish setter, which is entirely of a bright yellowish mahogany
+color; and the Gordon setter, which is entirely black, with orange
+color on the cheeks, under the throat, within and at the extremity of
+the limbs (Fig. 5). Next come the field spaniels, a group of terrier
+spaniels, which includes the Clumber spaniel, which is white and
+orange color; the Sussex spaniel, which is white and maroon; the black
+spaniel, which is wholly black; and the cocker, which is the smallest
+of all, and is entirely black, and white and maroon, or white and
+orange-colored, or tricolored.
+
+[Illustration: FIG 5.--GORDON SETTER.]
+
+_Barbets and Griffons_.--To this latter category belong the dogs, _par
+excellence_, for hunting in swamps. The barbets are entirely covered
+with long curly hair, like the poodles, which are directly derived
+from them. They are white or gray, with large black or brown blotches.
+The griffons differ from the poodles in their coarse and stiff hair,
+which never curls. They have large brown blotches upon a white ground,
+which is much spotted or mixed, as in the color of the hair called
+roan. There is an excellent white and orange-colored variety. The
+griffons, neglected for a long time on account of the infatuation that
+was and is still had for English hunting dogs, are being received
+again with that favor which they have never ceased to be the object of
+in Germany and in Italy (where they bear the name of _spinone_).
+Breeders of merit, such as Mr. Korthals, in Germany, and Mr. E.
+Boulet, in France, are endeavoring to bring them into prominence (Fig.
+6). Finally, we reckon also among hunting dogs some very happy
+crosses between the spaniels and the barbets, which in England are
+called retrievers or water spaniels.--_P. Megnin, in La Nature_.
+
+[Illustration: FIG 6.--COARSE HAIRED GRIFFON.]
+
+       *       *       *       *       *
+
+
+
+
+RESTOCKING THE SEINE WITH FISH.
+
+
+A few days ago, at Bougival, a short distance below the dam of the
+Marly machine, there were put into water 40,000 fry of California
+trout and salmon, designed to restock the Seine, which, in this
+region, has been depopulated by the explosions of dynamite which last
+winter effected the breaking up of the ice jam that formed at this
+place.
+
+[Illustration: RESTOCKING THE SEINE WITH FISH.]
+
+The operation, which is quite simple in itself, attracted a large
+number of inquisitive people by reason of the exceptional publicity
+given to the conflict provoked by a government engineer, who, under
+the pretext that he had not been consulted, made objections to the
+submersion of the little fish. As well known, the affair was
+terminated by a sharp reprimand from Mr. Yves Guyot, addressed to his
+overzealous subordinate.
+
+It would have been a great pity, moreover, if this interesting
+experiment had not taken place, and had not come to corroborate the
+favorable results already obtained.
+
+In three years the California salmon reaches a weight of eleven
+pounds, and, from this time, is capable of reproduction. Its flesh is
+delicious, and comparable to that of the trout, the development of
+which is less rapid, but just as sure.
+
+The fry put into the water on Sunday were but two months old. The
+trout were, on an average, one and a half inches in length, and the
+salmon two and three-quarter inches. They were transported in three
+iron plate vessels, weighing altogether, inclusive of the water, 770
+lb., and provided with air tubes through which, during the voyage, the
+employes, by means of pumps, assured the respiration of the little
+fish.
+
+Our engraving represents the submersion at the moment at which
+the cylinders (of which the temperature has just been taken and
+compared with that of the Seine, in order to prevent too abrupt a
+transition for the fry) are being carefully let down into the
+river.--_L'Illustration_.
+
+       *       *       *       *       *
+
+
+
+
+Figures show that the consumption of iron in general
+construction--other than railroads--in this country has grown from a
+little more than a million and a half of tons in 1879 to more than six
+million tons in 1889. Much of this increase has gone into iron
+buildings. By using huge iron frames and thin curtain walls for each
+story supported thereon, as is done in a building going up on lower
+Broadway, New York city, a good deal of space can be saved.
+
+       *       *       *       *       *
+
+
+
+
+MODERN ARMOR.
+
+By F.R. BRAINARD, U.S.N.
+
+
+The building of a navy, which has been actively going on for the past
+few years, has drawn public attention to naval subjects, and recent
+important experiments with armor plates have attracted large
+attention, hence it may not be amiss to give a description of the
+manufacture and testing of armor. It would be interesting to wade
+through the history of armor, studying each little step in its
+development, but we shall simply take a hasty glance at the past, and
+then devote our attention to modern armor and its immediate future.
+
+Modern armor has arrived at its present state of development through a
+long series of experiments. These experiments have been conducted with
+great care and skill, and have been varied from time to time as the
+improvements in the manufacture of materials have developed, and as
+the physical laws connected with the subject have been better
+understood. There has been very little war experience to draw from,
+and hence about all that is now known has been acquired in peaceful
+experiments.
+
+The fundamental object to be obtained by the use of armor is to keep
+out the enemy's shot, and thus protect from destruction the vulnerable
+things that may be behind it. The first serious effort to do this
+dates with the introduction of iron armor. With this form of armor we
+have had a small amount of war experience. The combat of the Monitor
+and Merrimac, in Hampton Roads, in May, 1862, not only marked an epoch
+in the development of models of fighting ships, but also marked one in
+the use of armor. The Monitor's turret was composed of nine one-inch
+plates of wrought iron, bolted together. Plates built in this manner
+form what is known as laminated armor. (See Fig. 1.) The side armor of
+the hull was composed of four one-inch plates. The Merrimac's casemate
+was composed of four one-inch plates or two two-inch plates backed by
+oak. The later monitors had laminated armor composed of one-inch
+plates. The foregoing, with the Albemarle and Tennessee rams under the
+Confederate flag, are about the sum of our practical experience in the
+use of armor.
+
+[Illustration: Fig. 1.]
+
+European nations took up the subject of armor and energetically
+conducted experiments which have cost large sums of money, but have
+given much valuable data. For a long time wrought iron was the only
+material used for armor, and the resisting power depending on the
+thickness; and the caliber and penetration of guns rapidly increasing,
+it was not long before a point was reached where the requisite
+thickness made the load of armor so great that it was impracticable
+for a ship to carry it. The question then arose as to what were the
+most important parts of a ship to protect. The attempted solutions of
+this question brought out various systems of distributions.
+
+Armored ships were formerly of two classes; in one the guns were
+mounted in broadside, in the other in turrets. Every part of the ship
+was protected with iron to a greater or less thickness. In more modern
+ships the guns are mounted in an armored citadel, in armored barbettes
+or turrets, the engines, boilers and waterline being the only other
+parts protected. There may be said to be three systems of armor
+distribution. The belt system consists in protecting the whole
+waterline by an armored belt, the armor being thickest abreast of the
+engines and boilers. The guns are protected by breastworks, turrets or
+barbettes, the other parts of the ship being unprotected. The French
+use the belt system, and our own monitors may be classed under it. The
+central citadel system consists in armoring that part of the waterline
+which is abreast of the engines and boilers. Forward and aft the
+waterline is unprotected, but a protective deck extends from the
+citadel in each direction, preventing the projectiles from entering
+the compartments below. The hull is divided into numerous compartments
+by water-tight bulkheads, and, having a reserve of flotation, the
+stability of the ship is not lost, even though the parts above the
+protective deck, forward and aft, be destroyed or filled with water.
+The guns are protected by turrets or barbettes. The deflective system
+consists in inclining the armor, or in so placing it that it will be
+difficult or impossible to make a projectile strike normal to the face
+of the plate. A plate that is inclined to the path of a projectile
+will, of course, offer greater resistance to penetration than one
+which is perpendicular; hence, when there is no other condition to
+outweigh this one, the armor is placed in such a manner as to be at
+the smallest possible angle with the probable path of the projectile.
+This system is designed to cause the projectile to glance or deflect
+on impact. Deflective armor should be at such an angle that the
+projectiles fired at it cannot bite, and hence the angle will vary
+according to the projectile most likely to be used. In the usual form
+of deflective deck the armor is at such a small inclination with the
+horizon that it becomes very effective. Turret and barbette armor may
+be considered as deflective armor. The term inclined armor denotes
+deflective armor that is inclined to the vertical. The kinds of armor
+that are in use may be designated as rolled iron, chilled cast iron,
+compound, forged and tempered steel, and nickel steel. Iron armor
+consists of wrought iron plates, rolled or forged, and of cast iron or
+chilled cast iron, as in the Gruson armor. Compound armor consists of
+a forged combination of a steel plate and an iron plate. Steel armor
+consists of wrought steel plates. Nickel-steel armor consists of
+plates made from an alloy of nickel and steel.
+
+I have spoken above of laminated armor. To secure the full benefit of
+this kind, the plates must be neatly fitted to each other; the
+surfaces must make close contact. This requires accurate machining,
+and hence is expensive. To overcome this point sandwiched armor was
+suggested. This consists in placing a layer of wood between the
+laminations, as shown in Fig. 2. It was found that laminated and
+sandwiched armor gave very much less resisting power than solid rolled
+plates of the same thickness. Wrought iron armor is made under the
+hammer or under the rolls, in the ordinary manner of making plates,
+and has been exhaustively studied and experimented with--more so than
+any other form of armor.
+
+[Illustration: Fig. 2.]
+
+Chilled cast iron armor is manufactured by Gruson, in Germany, and is
+used in sea coast defense forts of Europe.
+
+In 1867 several compound plates were made by Chas. Cammell & Co., of
+Sheffield, England, and were tested at Shoeburyness, in England, and
+at Tegel, in Russia. These plates were made by welding slabs of steel
+to iron; but the difficulties were so great that the idea was
+abandoned for the time.
+
+[Illustration: Fig. 3.]
+
+[Illustration: FIG. 4.]
+
+Compound armor, as now manufactured, is of two types: Wilson's patent,
+a backing of rolled iron, faced with Bessemer steel; Ellis' patent, a
+backing of rolled iron, faced with a plate of hard rolled steel,
+cemented with a layer of Bessemer steel. Both these kinds are
+manufactured in England and France in sizes up to fifty tons weight.
+The Wilson process is used at the works of Messrs. Cammell & Co., of
+Sheffield, England, and the Ellis process at the Atlas Works of Sir
+John Brown & Co., of the same place. These are the two leading
+manufacturers of compound plate.
+
+[Illustration: Fig. 5.]
+
+The method employed by Wilson in making compound plate is to first
+make a good wrought iron plate. To the surface of this and along each
+side of the length of the plate are fixed two small channel irons, as
+shown in Fig. 5. The plate is then raised to a welding heat in a gas
+furnace, and transferred to an iron flask or mould. Wedges are driven
+in between the back of the plate and the side of the mould, thus
+forcing the channel irons up snug against the opposite side of the
+mould. Moulding sand is then packed around the back and sides of the
+plate (see Fig. 6). The mould is lowered in a vertical position into a
+pit. Molten steel, manufactured by either the Siemens-Martin or
+Bessemer process, is then poured in through a trough that forms
+several streams, and forms the hard face of the plate. The molten
+steel as it runs down cleans the face of the wrought iron plate,
+scoring it in places, and, being of much higher temperature, the
+excessive heat carbonates the iron to a depth of one-eighth to
+three-sixteenths of an inch, forming a zone of mild steel between the
+hard steel and soft iron. The mould is placed in a vertical position
+to insure closeness of structure and the forcing of gases out of the
+steel. After solidifying, the whole plate is pressed, and passed
+through the rolls to obtain thorough welding. It is then bent, planed,
+fitted, tempered, and annealed to remove internal strains.
+
+[Illustration: Fig. 6.]
+
+In 1887, Wilson took out a patent for improvements in his process of
+making compound plates. In this method of manufacture he takes a
+wrought iron, fibrous plate, fifteen inches thick, built up from a
+number of thin plates. While hot from the forging press, he places
+this plate in an iron mould (see Fig. 7) about 28 inches deep, and
+upon it runs "ingot iron" or very mild steel to a depth of thirteen
+inches. In this form of mould the plate rests on brickwork, and is
+held in place by two grooved side clamps or strips which are caused to
+grip the plate by means of screws which extend through the sides of
+the mould. After solidifying, the plate, which is twenty-eight inches
+thick, is reheated and rolled down to eighteen inches. This is the
+iron backing of the finished plate, and it is again put in the iron
+mould and heated, when a layer of hard steel is run on the exposed
+surface of the original wrought iron plate to a depth of eight inches.
+This makes a plate about twenty-eight inches thick. It is taken from
+the mould, reheated, rolled, hammered or pressed down to twenty
+inches. After cooling, it is bent, planed, and fitted as desired, then
+tempered and annealed to relieve internal strains.
+
+[Illustration: Fig. 7.]
+
+The method employed by Ellis in making compound plates is to take two
+separate plates, one of good wrought iron and one of hard forged
+steel, placing the forged steel plate on the wrought iron plate,
+keeping them separate by a wedge frame or berm of steel around three
+sides, and placing small blocks of steel at various points near the
+middle of the plates (see Fig. 8). These blocks are called distance
+blocks. After covering all the exposed steel surfaces with ganister,
+the plates are put in a gas furnace and heated to a welding heat. They
+are then lowered into a vertical iron pit with the open side
+uppermost. The plates are held in position by hydraulic rams, which
+also prevent bulging. Molten steel of medium softness is then poured
+into the space between the plates, by means of a distributing trough
+having holes in the bottom, and after this has solidified, the whole
+plate is placed under the hydraulic press and reduced about twenty per
+cent. in thickness. The plate is then passed through the rolls, bent,
+planed, fitted, tempered, and annealed to reduce internal strains.
+
+[Illustration: Fig. 8.]
+
+In heating the compound plates for rolling, the plate is placed in the
+furnace with the steel face down, so that the iron part gets well
+heated and the steel does not become too hot. Great care must be taken
+not to overheat the plate, and in working, many passes are given the
+plate with small closings of the rolls. The steel part of a compound
+plate is usually about one third of the full thickness of the plate.
+
+Forged steel armor, tempered in oil, is fabricated at Le Creusot,
+France, by Schneider & Co., using open-hearth steel, and forging under
+the 100 ton hammer. The ingots are cast, with twenty-five per cent.
+sinking head and are cubical in form. The porter bar is attached to a
+lug on one side of the ingot. By means of a crane with a curved jib
+which gives springiness under the hammer, the ingot is thrust into the
+heating furnace. On arriving at a good forging heat it is swung around
+to the 100 ton hammer, under which it is worked down to the required
+shape. A seventy-five ton ingot requires about eight reheatings before
+being reduced to shape. Having been reduced to shape, the plate is
+carefully annealed, then raised to a high tempering heat, and the face
+tempered in oil. It is reannealed to take out the internal strains,
+care being taken not to reduce the face hardness more than necessary.
+The Schneider process of tempering is based upon the utilization of
+the absorption of heat caused by the fusing or melting of a solid
+substance, and of the fact that so long as a solid is melting or
+dissolving in a liquid substance, the liquid cannot get appreciably
+hotter, except locally around the heating surface. The body to be
+hardened is plunged at the requisite temperature into a bath
+containing the solid melting body, or is kept under pressure in the
+solid material of low melting point until the required extraction of
+heat has taken place, more solid material being added if necessary as
+that originally present melts and dissolves.
+
+Nickel steel armor is made in a similar manner to the steel plates,
+the material used in casting the ingot being an alloy of nickel and
+steel containing between three and four per cent. of nickel.
+
+The Harvey process of making armor consists in taking an all-steel
+plate and carbonizing the face. This carbonizing process is very
+similar to the cementation process of producing steel, and by it the
+face of the plate is made high in carbon and very hard.
+
+The system invented by Sir Joseph Whitworth, of Manchester, England,
+consists in what might be called scale armor. A section of a sample of
+the armor represents four plates. The outer layer, one inch thick, is
+composed of steel of a tensile strength of 80 tons per square inch;
+the second layer, one inch thick, of steel whose tensile strength is
+40 tons per square inch; the third and fourth layers, each one-half
+inch thickness, of mild steel. The outer layer is in small squares of
+about ten inches on a side, and is fastened to the second layer by
+bolts at the corners and one in the middle of each square. The surface
+is flush. (See Fig. 9.) The end sought by the above system is to break
+up the shot by the hard steel face and to restrict any starring or
+cracking of the metal to the limit of the squares or scales struck.
+The bolts are of high carbon and are extremely hard steel.
+
+[Illustration: Fig. 9.]
+
+Armor plates must often be bent or curved to single or double
+curvature and sometimes to a warped surface to fit the form of the
+ship. There are several methods of bending plates. One method employs
+a cast iron slab of the required form, which is placed on the piston
+of a hydraulic press. The armor plate is placed face down on this
+slab, and on top of the plate are laid packing blocks of cast iron, of
+such sizes and shapes as to conform to the required curve. These
+blocks take against the upper table of the press, when the piston is
+forced up, and the hot plate is thus dished to the proper form.
+
+In the French method of bending, an anvil or bed plate of the required
+curve is used, and the armor plate is forced to take the curve by
+being hammered all over its upper surface with a specially designed
+steam hammer.
+
+The edges of the plate are trimmed by large, powerful slotting
+machines or circular saws; the latter, however, operate in exactly the
+same manner as a slotter, except that there is no return motion to the
+tool. Each tooth of the saw is but a slotting tool, and these teeth
+are, by screws, rendered capable of being nicely adjusted in the
+circumference of the saw.
+
+The plates are fastened to the hulls and backing by heavy bolts,
+varying in size according to the weight of the individual plate. For
+the 6,000 ton armored ships, these bolts are from 2.75 to 3.1 inches
+in diameter and from 18.45 to 23 inches in length. They are tapped two
+or three inches into the armor and do not go through the plate. They
+pass through wrought iron tubes in the backing and set up with cups,
+washers and nuts against the inner skin of the ship.
+
+At steel works where plates for our new navy are being manufactured,
+there are inspectors who look after the government's interests.
+Officers of the navy are detailed for this work, and their duty is to
+watch the manufacture of plates through each part of the process and
+to see that the conditions of the specifications and contract are
+complied with.
+
+The inspection and testing of armor plates consists in examining them
+for pits, scales, laminations, forging cracks, etc., in determining
+the chemical analysis of specimens taken from different parts, in
+determining the physical qualities of specimens taken longitudinally
+and transversely, and the ballistic test. Specifications for these
+different tests are constantly undergoing change, and it would be
+impossible to state, with exactness, what the requirements are or will
+be in the near future. The ballistic test is the important one, and is
+made by taking one plate of a group and subjecting it to the fire of a
+suitable gun. The other tests are simply to insure, as far as
+practicable, that all the other plates of the group are similar to and
+are capable of standing as severe a ballistic test as the test plate.
+
+The following will give an idea of the ballistic test as prescribed by
+the Bureau of Ordnance, Navy Department. The test plate, irrespective
+of its thickness, is to be backed by thirty-six inches of oak or other
+substantial wood. Near the middle region of the plate an equilateral
+triangle will be marked, each side of which will be three and one-half
+calibers long. The lower side of the triangle will be horizontal.
+Three shots will be fired, the points of impact being as near as
+possible the extremities of the triangle. The velocity of the shot
+will be such as to give the projectile sufficient energy to just pass
+through a wrought iron plate of equal thickness to the test plate, and
+through its wood backing. The velocity is calculated by the Gavre
+formula:
+
+              a
+       V² =  --- { 3507 E² × 2265464 e^{1.4} }
+              w
+
+[TEX: V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}]
+
+  V = the velocity of the projectile in feet per second.
+  a = the diameter of the projectile in inches.
+  w = the weight of the projectile in pounds.
+  E = the thickness of the backing in inches.
+  e = the thickness of the plate in inches.
+
+Using the above formula we can make out a table as follows:
+
+-------+-------+-------------+-------+-------+------+---------+
+Plate. |Backi'g| Gun, service|  w,   |  a,   |  V.  | Energy, |
+Inches.|Inches.| shot.       |Pounds.|Inches.| f. 8.| Impact. |
+       |       |             |       |       |      | f. tons.|
+-------+-------+-------------+-------+-------+------+---------+
+  6    |  36   |   6" B.L.R. |  100  |  5.96 | 1389 |  1337   |
+  7    |  36   |   6"   "    |  100  |  5.96 | 1528 |  1619   |
+  8    |  36   |   8"   "    |  250  |  7.96 | 1213 |  2550   |
+  9    |  36   |   8"   "    |  250  |  7.96 | 1308 |  2966   |
+ 10    |  36   |   8"   "    |  250  |  7.96 | 1399 |  3390   |
+ 11    |  36   |   8"   "    |  250  |  7.96 | 1489 |  3839   |
+ 12    |  36   |  10"   "    |  500  |  9.96 | 1247 |  5386   |
+ 13    |  36   |  10"   "    |  500  |  9.96 | 1315 |  5987   |
+ 14    |  36   |  10"   "    |  500  |  9.96 | 1381 |  6608   |
+ 15    |  36   |  12"   "    |  850  | 11.96 | 1215 |  8699   |
+ 16    |  36   |  12"   "    |  850  | 11.96 | 1269 |  9710   |
+ 17    |  36   |  12"   "    |  850  | 11.96 | 1332 | 10454   |
+ 18    |  36   |  12"   "    |  850  | 11.96 | 1374 | 11124   |
+ 19    |  36   |  12"   "    |  850  | 11.96 | 1425 | 11965   |
+ 20    |  36   |  12"   "    |  850  | 11.96 | 1476 | 12837   |
+-------+-------+-------------+-------+-------+------+---------+
+
+
+No projectile or fragment of the plate or projectile must get wholly
+through the plate and backing. The plate must not break up or give
+such cracks as to expose the backing, previous to the third shot.
+
+The penetration of projectiles of different forms into various styles
+of armor has been very thoroughly studied and many attempts have been
+made to bring the subject down to mathematical formulæ. These formulæ
+are based on several suppositions, and agree very closely with results
+obtained in actual experiments, but there are so many varying
+conditions that it is extremely doubtful if any formulæ will ever be
+written that will properly express the penetration.
+
+Many different forms have been given to the heads of projectiles, as
+flat, ogival, hemispherical, conoidal, parabolic, blunt trifaced, etc.
+
+The flat headed projectile has the shape of a right cylinder, and acts
+like a punch, driving the material of the armor plate in front of it.
+These projectiles are especially valuable when firing at oblique
+armor, for they will bite or cut into the armor when striking at an
+angle of thirty degrees.
+
+The ogival head acts more as a wedge, pushing the metal aside, and
+generally will give more penetration in thick solid plates than the
+flat headed projectile. The ogival head is usually designed by using a
+radius of two calibers.
+
+The hemispherical, conoidal, parabolic and blunt trifaced all give
+more or less of the wedging effect. The blunt trifaced has all the
+good qualities of the ogival of two calibers. It bites at a slightly
+less angle, and the three faces start cracks radiating from the point
+of impact.
+
+Forged steel is the best material for armor-piercing projectiles, but
+many are made of chilled cast iron, on account of its great hardness
+and cheapness.
+
+The best weight for a projectile is found by the formula
+
+    w = d³ (0.45 to 0.5)
+
+w being the weight in pounds, d the diameter in inches and 0.45 to 0.5
+having been determined by experiment.
+
+With a light projectile we get a flat trajectory, and accuracy at
+short ranges is increased. With a heavy projectile the resistance of
+the air has less effect and the projectile is advantageously employed
+at long ranges.
+
+In the following formulæ, used in calculating the penetration of
+projectiles in rolled iron armor,
+
+  g = the force of gravity.
+  w = the weight of projectile in pounds.
+  d = the diameter of projectile in inches.
+  v = the striking velocity in feet per second.
+  P = the penetration in inches.
+
+
+Major Noble, R.A., gives
+
+              _________________
+         1.6 /      w v²
+   P =  /\  /  ----------------
+          \/   [pi] g d 11334.4
+
+[TEX: P = \sqrt[1.6]{\frac{w \ v^2}{\pi \  g \  d \ 11334.4}}]
+
+U.S. Naval Ordnance Proving Ground uses
+
+              ________________
+        2.035/      w v²
+   P =  /\  /  ---------------
+          \/   [pi] g d 3852.8
+
+[TEX: P = \sqrt[2.035]{\frac{w \ v^2}{\pi \  g \  d \ 3852.8}}]
+
+Col. Maitland gives
+
+            w v²
+   P =  ------------
+        g d² 16654.4
+
+[TEX: P = \frac{w \ v^2}{g \  d^2 \ 16654.4}]
+
+Maitland's latest formula, now used in England, is
+
+                 _
+          v     /w
+    P = ----- \/ - - 0.14 d
+        608.3    d
+
+[TEX: P = \frac{v}{608.3} \sqrt{\frac{w}{d}} - 0.14 \ d]
+
+General Froloff, Russian army, gives
+
+         w v
+    P = ------
+        d² 576
+
+[TEX: P = \frac{w \ v}{d^2 \ 576}]
+
+for plates less than two and one-half inches thick, and
+
+         w v
+    P = ------ - 1.5
+        d² 400
+
+[TEX: P = \frac{w \ v}{d^2 \ 400} - 1.5]
+
+for plates more than two and one-half inches thick.
+
+
+If [theta] be the angle between the path of the projectile and the
+face of the plate, then v in the above formulæ becomes v sin [theta].
+
+When we come to back the plates, their power to resist penetration
+becomes greater, and our formula changes. The Gavre formula, given
+above, is used to determine the velocity necessary for a projectile to
+pass entirely through an iron plate and its wood backing.
+
+Compound and steel armor are said to give about 29 per cent. more
+resisting power than wrought iron, but in one experiment at the
+proving ground, at Annapolis, a compound plate gave over 50 per cent.
+more resisting power than wrought iron.
+
+The Italian government, after most expensive and elaborate comparative
+tests, has decided in favor of the Creusot or Schneider all-steel
+plates, and has established a plant for their manufacture at Terni,
+near Rome.
+
+The French use both steel and compound plates; the Russians, compound;
+the Germans, compound; the Swedes and Danes use both. Spain has
+adopted and accepted the Creusot plate for its new formidable armored
+vessel, the Pelayo; and China too has recently become a purchaser of
+Creusot plates.
+
+Certain general rules may be laid down for attacking armor. If the
+armor is iron, it is useless to attack with projectiles having less
+than 1,000 feet striking velocity for each caliber in thickness of
+plate. It is unadvisable to fire steel or chilled iron filled shells
+at thick armor, unless a normal hit can be made. When perforation is
+to be attempted, steel-forged armor-piercing shells, unfilled, should
+be used. They may be filled if the guns are of great power as compared
+to the armor. Steel and compound armor are not likely to be pierced by
+a single blow, but continued hammering may break up the plate, and
+that with comparatively low-powered guns.
+
+Wrought iron must be perforated, and hard armor, compound or steel,
+must be broken up. Against wrought iron plates the projectile may be
+made of chilled cast iron, but hard armor exacts for its penetration
+or destruction the use of steel, forged and tempered. Against
+unarmored ships, and against unarmored portions of ironclads, the
+value of rapid-firing guns, especially those of large caliber, can
+hardly be overestimated.
+
+The relative value of steel and compound armor is much debated, and at
+present the rivalry is great, but the weight of evidence and opinion
+seems to favor the all-steel plate. The hard face of a compound plate
+is supposed to break up the projectile, that is, make the projectile
+expend its energy on itself rather than upon the plate, and the
+backing of wrought iron is, by its greater ductility, to prevent the
+destruction of the plate. It seems probable that these two systems
+will approach each other as the development goes on. An alloy of
+nickel and steel is now attracting attention and bids fair to give
+very good results.
+
+The problem to be solved, as far as naval armor is concerned, is to
+get the greatest amount of protection with the least possible weight
+and volume, and this reduction of weight and volume must be
+accomplished, in the main, by reducing the thickness of the plates by
+increasing the resisting power of the material. In the compound plate
+great surface hardness is readily and safely attained, but it has not
+yet been definitely determined what the proper proportionate thickness
+of iron and steel is.
+
+A considerable thickness of steel is necessary to aid, by its
+stiffness, in preventing the very ductile iron from giving back to
+such an extent as to distort the steel face and thus tear or separate
+the parts of the plate. The ductile iron gives a very low resisting
+power, its duty being to hold the steel face up to its work. If now we
+substitute a soft steel plate in the place of the ductile iron, we
+will get greater resisting power, but our compound plate then becomes
+virtually an all-steel one, only differing in process of manufacture.
+The greatest faults of the compound plate are the imperfect welding of
+the parts and the lack of solidity of the iron. When fired at, the
+surface has a tendency to chip.
+
+In the all-steel plate we have the greatest resisting power
+throughout, but there are manufacturing difficulties, and surface
+hardness equal to that of the compound plate has not been obtained.
+The manufacturing difficulties are being gradually overcome, and
+artillerists are in high hopes that the requisite surface hardness
+will soon be obtained.
+
+The following may be stated as well proved:
+
+1. That steel armor promises to replace both iron and compound.
+
+2. That projectiles designed for the piercing of hard armor must be
+made of steel.
+
+3. That the larger the plate, the better it is able to absorb the
+energy of impact without injury to itself.
+
+4. That the backing must be as rigid as possible.
+
+       *       *       *       *       *
+
+[FROM ENGINEERING.]
+
+
+
+
+THE COMPRESSED AIR SYSTEM OF PARIS.
+
+
+The demand for compressed air as a motive power is constantly
+increasing in Paris; the company, according to its official reports,
+is financially prosperous, and it seems difficult to understand how it
+should continue as an actively going concern, unless it at all events
+paid its way. The central station of St. Fargeau, originally started
+on modest lines, for maintaining a uniform time by pneumatic pressure
+throughout Paris, has grown rapidly to very large proportions, though
+it has never been able to supply the demand made on it for power; and
+at the present time a second and still larger station is being
+constructed in another part of Paris. We confess that we do not
+understand why such large sums of money should continue to be spent if
+the enterprise is not commercially a sound one, nor how men of such
+eminence in the scientific world as Professor Riedler should, without
+hesitation, risk their reputation on the correctness of the system, if
+it were the idle dream of an enthusiast, as many persons--chiefly
+those interested in electric transmission--have declared it to be.
+
+[Illustration: Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION]
+
+In describing the developments that have taken place during the last
+two years, we shall confine ourselves entirely to the details of a
+report recently made on the subject by Professor Riedler. As soon as
+it became evident that a very largely increased installation was
+necessary, it was determined that the new central station should be as
+free as possible from the defects of the first one. These defects,
+which were the natural results of the somewhat hasty development of an
+experimental system, were of several kinds. In the first place, so
+large a growth had not been contemplated, and the extensions were
+made more or less piecemeal, instead of being on a regular plan; the
+location of the central station itself was very unfavorable, both as
+regards the facilities for obtaining coal and other supplies; the cost
+of water was excessive, and the amount available, inadequate.
+
+This evil was partly remedied by elaborate arrangements for cooling
+the injection water so that it could be repeatedly used, a device
+costly and ineffective, and resulting in extravagant working, to say
+nothing of the high charges made by the Paris company for supplying
+water. To these drawbacks had to be added others of an even more
+serious character. The engines first laid down were not economical,
+and the compressors employed gave but a very inferior result; with
+each extension of the plant, the efficiency of both engines and
+compressors was increased, the most satisfactory, we believe, having
+been those supplied by the Societe Cockerill, and one of which was
+exhibited at the Paris exhibition in 1889. Still it was clearly
+recognized that much better results were possible, results which
+Professor Riedler claims have been attained and which will be embodied
+in the new installation now in progress.
+
+This central station is located on the left bank of the Seine, close
+to the fortifications, opposite Vincennes and not far from the
+terminal stations of the Orleans and the Paris, Lyons, and
+Mediterranean Railways; the plan, Fig. 1, shows the position. The
+works are separated from the river by the quay, over which a bridge
+will be constructed for the transfer of coal from the landing stages
+belonging to the company, into the works; as will be readily seen from
+the plan, it would be quite easy to run junction lines to the two
+adjacent railways, but with all the advantages given by water
+carriage, it was considered unnecessary to incur the expense. The
+river also affords a constant and unlimited water supply, so that none
+of the difficulties existing at St. Fargeau Station in imperfect
+condensation and cooling will be met with.
+
+The new installation, called the Central Station of the Quai de la
+Gare, is laid out on a very large scale, the total generating energy
+provided for being no less than 24,000 horse power; of this it is
+intended that 8,000 horse power will be in operation this year, and an
+extension of 10,000 horsepower in 1892; the power now in course of
+completion comprises four engines of 2,000 horse power each. Four
+batteries of boilers will provide steam for these engines. Figs. 2, 3,
+and 4 show the first section of the installation now in progress; the
+four groups of engines (three-cylinder condensing) are shown at 1, 2,
+3, and 4; the four groups of boilers ranged behind them at F, F; the
+feed water heaters belonging to each group at V V.
+
+[Illustration: COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS.
+(FIG. 2,3,4)]
+
+The end of the building abuts against the Seine, and the position of
+the water conduits for inlet and discharge are indicated at C and A
+respectively. The installation, when completed, will include very
+extensive arrangements for transporting and storing coal, and the
+interior of the boiler houses will be furnished with an overhead
+system of rails and carriers for handling the coal automatically, as
+far as possible. All the principal mains and steam pipes are made in
+duplicate, not only for greater security, but in order that each set
+of engines and boilers may be connected interchangeably without delay.
+The Seine supplies an ample quantity of water, but not in a condition
+either for feeding the boilers, for condensation, or for the air
+compressors.
+
+[Illustration: THE NEW COMPRESSED AIR STATION AT PARIS. (FIG. 5, 6)]
+
+Special provisions have therefore to be made to filter the water
+efficiently before it is used. For this purpose the water is led to a
+group of four filters (see L, Fig. 4); from them it passes into the
+tanks, JJ, and is pumped into the heaters. The filters can be rapidly
+and automatically cleaned by reversing the flow of water through them.
+Figs. 5 and 6 show the general form of the type of engine adopted, as
+well as the engine house, some of the mains, etc. They are vertical
+triple-expansion engines, and are being constructed by MM. Schneider
+et Cie, of Creusot, with a guarantee of coal consumption not to exceed
+1.54 lb. per horse power per hour, with a penalty of 2,000 francs for
+every 100 grammes in excess of this limit. It is evident that with
+this restricted fuel consumption, a large margin for economy will
+exist at the new works, as compared with the St. Fargeau station,
+where the best engines cannot show anything like this result, while
+some of the earlier ones are distinctly extravagant, and the whole
+installation is handicapped with imperfect means of condensation.
+
+Moreover, according to Professor Riedler, the consumption of steam by
+the new Schneider engines will be only 5.3 kilos. per horse power and
+per hour as compared with some of the large engines requiring 9
+kilos., and the Cockerill engines--using 8 kilos. per hour, not to
+speak of the older motors that are very extravagant in the use of
+steam. The St. Fargeau station is worked under a further disadvantage.
+The constantly increasing demand from subscribers taxes the resources
+of the station to their fullest extent, so that practically there is
+no reserve power.
+
+In the new installation the work will be equally constant, but care
+will be taken always to have a sufficient reserve. Electric lighting
+will form a considerable part of the duty to be done from this
+station, and in all cases it is intended to work with accumulators, so
+that the resistance to be overcome by the engines, so far as this part
+of the duty is concerned, will be well known and uniform. The
+engineers of the Compressed Air Co., of Paris, have during the last
+five years acquired an experience which could only be attained at a
+high price and at the expense of a certain amount of failure; this
+period, it is claimed, is now passed, and in the new installation it
+is possible to put into practice all the valuable lessons learned at
+St. Fargeau, to say nothing of the more favorable natural conditions
+under which the extension is being started and the improvements in the
+compression of the air made by Mr. Popp and Professor Riedler, and to
+which we shall refer later.
+
+Chiefly in consequence of the high value of the ground, vertical
+engines were adopted at the new station; the proximity to the river
+made the foundations somewhat costly, and the risk of occasional
+floods rendered it desirable to set the level of the engine bedplates
+20 inches above the floor of the building; the foundations of the
+engines are continuous, but are quite independent of the building.
+There are three compressing cylinders in each set of engines, one
+being above each steam cylinder. Two of these are employed to compress
+the air to about 30 lb. per square inch, after which it passes into a
+receiver and is cooled; it is then admitted into the third or final
+compressing cylinder and raised to the working pressure at which it
+flows into the mains. In the illustrations, h, m, and b are the high,
+intermediate, and low pressure cylinders of one set of engines; as
+will be seen, each cylinder is on a separate frame connected by
+girders; directly above the cylinders are the two low and the one high
+pressure air cylinders, b¹, m¹, and h¹ respectively. The former
+deliver the air compressed to the first stage into the receiver, T¹
+(see Fig. 5), whence it passes into the third compression cylinder,
+and thence by a main into the cylinders, R R, which are in direct
+communication with the delivery mains; these mains terminate in the
+subway, T. The water for condensation is brought into the engine house
+by the channel, C, and the condenser pumps, a, draw direct from this
+supply; the discharge main back to the river is shown at A. The
+relative positions of the engine and boiler houses are indicated in
+Figs. 2 to 5, where F shows the end of one group of boilers; the air
+supply for the compressors is led from the central raised portion, S,
+of the roof.
+
+Professor Riedler's first experiments in improving the efficiency of
+air compressors were made with one of the Cockerill compressors in use
+at the St. Fargeau Station, and considerable difficulty attended this
+work, because the machinery was necessarily kept almost in constant
+operation. These compressors were designed by MM. Dubois and Francois,
+of Seraing. Two of their leading features were the delivery of the
+compressed air at as low a temperature as possible, and with a
+relatively high piston speed of about 400 ft. a minute. The former
+object is attained by the injection of a very fine water spray at each
+end of the air cylinder, and its rapid removal with each stroke; the
+free as well as the compressed air flows through the same passages,
+one at each end of the cylinder; the inlet valves being placed at the
+side of these passages, and the outlet or compressed air valves at the
+top, the compressed air, entering a chamber above the cylinder, common
+to both valves, and passing thence to the reservoir. The compressed
+air valves, which are seven in. in diameter, are brought back sharply
+to their seats at each stroke, by a small piston operated by
+compressed air flowing through a by-pass from the chamber. The
+illustrations published by us on page 686 of our forty-seventh volume
+show the construction of these compressors. The engravings on page 683
+of the same volume illustrate the compressors used in a somewhat older
+part of the installation; they were made by M. Blanchod, of Vevey, and
+a passing reference may be made to them. The air is admitted through
+valves in the cylinder, and is forced out through spring-loaded
+valves; water is admitted into the cylinder to cool the air.
+
+Fig. 7 indicates the modification made by Professor Riedler in one of
+the Cockerill compressors: a receiver, A, was placed under the two
+compressing cylinders, B and C. The first stage is completed in the
+large cylinder, B, the air being compressed to about 30 lb. per square
+inch; from this it is discharged into the receiver, A, through the
+pipe, B¹, where it meets with a spray injection that cools it to the
+temperature of the water. The final stage is then effected in the
+smaller cylinder, C, which, drawing the air from the receiver through
+the pipe, C¹, compresses it to about 90 lb. and delivers it through
+the pipe, d, to the mains. We hope shortly to publish drawings of this
+compressor in its final form; in its elementary stage Professor
+Riedler claims to have obtained some very remarkable results. He says
+that the waste spaces in his modification were much smaller than in
+the Cockerill compressor, while the efficiency of the apparatus was
+largely increased. The actual engine duty per horse power and per hour
+was raised, as a maximum, to 384 cubic feet of air at atmospheric
+pressure, and compressed to 90 lb. per square inch, a marked increase
+on the duty of the compressors in use at the St. Fargeau station. The
+Cockerill compressors experimented on at the same time showed a
+maximum duty of 306 cubic feet of air. A considerable advantage is
+claimed in drawing clean and cool air from the outside of the
+building, and beyond the main feature of carrying out the compression
+in two stages, Mr. Riedler appears to have shown great skill in
+introducing several minor alterations and improvements in the plant.
+
+[Illustration: EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig.
+8, 9, 10)]
+
+Figs. 8, 9 and 10 are diagrams showing the comparative efficiency of
+the three types of compressors at St. Fargeau--Fig. 10 being a diagram
+of the Riedler compressor--and indicate the gain derived from the
+intermediate cooling. The loss is shown to be only 12 per cent., as
+compared with a loss of 43 per cent. in a large part of the plant, and
+of 105 per cent. in the earlier compressors of the St. Gothard type.
+The table given herewith contains a summary of trials made by
+Professor Gutermuth, and are intended to show the comparative results
+of an extended trial with three kinds of compressors at St. Fargeau.
+
+  PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
+
+--------------+-------+--------+------+-------+--------+--------+---------+
+              | R   p |        |  E   |       |        |        |         |
+              | e o e | Horse- |  f   |Amount |Quantity| Cubic  |         |
+Compressors.  | v f r | Power  |  f   |of Air | of Air |Feet of |Final Air|
+              | o     |Absorbed|  i   |Passing| Passing|Air per |Pressure.|
+              | l E m |   by   |  c   |through| through| Horse- |         |
+              | u n i |Compres-|  i   | Inlet | Valves | Power  |         |
+              | t g n | sors.  |  e   | Valves| per    | and per|         |
+              | i i u |        |  n   | each  | Hour.  |  Hour. |         |
+              | o n t |        |  c   |Revolu-|        |        |         |
+              | n e e |        |  y   | tion. |        |        |         |
+              | s   . |        |  .   |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+              |       |        |      | cubic |  cubic |        |lb. per  |
+1.            |       |        |      | feet  |  feet  |        |sq. in.  |
+_Sturgeon_    |       |        |      |       |        |        |         |
+_Compressor_  |  37   |   302  | .87  | 41.67 |  91,507| 261.3  | 90      |
+Diameter of   |  37   |   258  | .87  | 38.13 |  84,650| 276.1  | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+23.62 in.     |       |        |      |       |        |        |         |
+and 21.66 in.;|       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+48.63 in.     |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+2.            |       |        |      |       |        |        |         |
+_Cockerill_   | 40    |   337  | .83  | 46.61 | 111,864| 281.83 | 90      |
+_Compressor._ | 45    |   353  | .83  | 46.61 | 125,844| 302.66 | 90      |
+Diameter of   | 40    |   342  | .88  | 49.43 | 118,632| 296.65 | 90      |
+cylinder,     | 46    |   377  | .85  | 48.02 | 132,534| 298.77 | 90      |
+25.98 in.;    | 38.67 |   324  | .89  | 50.14 | 116,434| 306.19 | 90      |
+stroke,       | 38.5  |   337  | .89  | 50.14 | 115,818| 294.18 | 90      |
+47.24 in.     | 38.6  |   329  | .91  | 50.84 | 117,740| 305.13 | 90      |
+              |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+3.            |       |        |      |       |        |        |         |
+_Riedler_     | 52    |   615  | .985 | 77.34 | 241,300| 353.50 | 90      |
+_Compressor._ | 60    |   709  | .985 | 76.98 | 277,128| 353.50 | 90      |
+Diameter of   | 38    |   422  | .985 | 77.34 | 176,330| 376.12 | 90      |
+low-pressure  | 39    |   424  | .985 | 77.34 | 181,030| 384.60 | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+42.91 in.;    |       |        |      |       |        |        |         |
+diameter of   |       |        |      |       |        |        |         |
+high-pressure |       |        |      |       |        |        |         |
+cylinder,     |       |        |      |       |        |        |         |
+26.38 in.;    |       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+47.24 in.     |       |        |      |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+
+
+The results thus obtained were so satisfactory that the designs were
+prepared for the great compressors to be operated at the new central
+station on the Quai de la Gare by the 2,000 horse power engines.
+
+The transmission of the compressed air through the mains is
+unavoidably attended with a certain percentage of loss, which, of
+course, increases with the length of the transmission, the presence of
+leakage at the joints, etc. Professor Riedler has devoted considerable
+time to the investigation of this source of waste, and we shall
+presently refer to the results he has recorded; in the first place,
+however, we propose to consider what he has to say on the subject of
+utilizing the air at the points of delivery, and the means employed
+for obtaining a relatively high efficiency of the motor.
+
+In the earliest stages of the Popp system in Paris it was recognized
+that no good results could be obtained if the air were allowed to
+expand direct into the motor; not only did the formation of ice due to
+the expansion of the air rapidly accumulate and choke the exhaust, but
+the percentage of useful work obtained, compared with that put into
+the air at the central station, was so small as to render commercial
+results hopeless. The practice of heating the air before admitting it
+to the motor is quite old, but until a few years ago it never seems to
+have been properly carried out; in several mining installations where
+this motive power had been long used, more or less imperfect attempts
+had been made to heat the air; in one instance only, recorded by
+Professor Riedler, was an efficient means employed. In this case a
+spray of boiling water was injected into the cylinder and mixed with
+the air at each stroke, with the result that a very marked economy was
+obtained.
+
+After a number of experiments, Mr. Popp arrived at the conclusion that
+the simplest mode of heating, if not the most efficient, was at all
+events the most suitable, as it was a matter of the first importance
+that subscribers should not be troubled with the charge of any
+apparatus involving complication or careful management; he therefore
+adopted a simple form of cast iron stove lined with fireclay, heated
+either by a gas jet or by a small coke fire. It was found that this
+apparatus, crude as it was, answered the desired purpose, until some
+better arrangement was perfected, and the type was accordingly adopted
+throughout the whole system. It was quite recognized that this method
+still left much to be desired, and the economy resulting from the use
+of an improved form was very marked.
+
+From a large number of trials very carefully carried out by Professor
+Gutermuth, it was found that more than 70 per cent. of the total
+number of calories in the fuel employed was absorbed by the air and
+transformed into useful work. Whether gas or coal be employed as the
+fuel, the amount required is so small as to be scarcely worth
+consideration; according to the experiments carried out, it does not
+exceed 0.09 kilo. per horse power and per hour, but it is scarcely to
+be expected that in regular practice this quantity is not largely
+exceeded. Professor Weyrauch has also carefully investigated this part
+of the subject and fully confirms, if he, indeed, does not go beyond
+Professor Gutermuth. He claims that the efficiency of fuel consumed in
+this way is six times greater than when burnt under a boiler to
+generate steam. He goes so far as to assert that with a good method of
+heating the air, not only can all the losses due to the production and
+the transmission of the compressed air be made good, but also that it
+will actually contain more useful energy at the motor than was
+expended at the central station in compressing it.
+
+According to Professor Riedler, from 15 to 20 per cent. above the
+power at the central station can be obtained by means at the disposal
+of the power users, and it has been shown by experiment that by
+heating the air to 250 deg. Cent. an increased efficiency of 30 per
+cent. can be obtained. Better results than those heretofore obtained
+may, therefore, be confidently expected with a more perfect and
+economical application of the fuel in heating the air, and a better
+means of regulation in admitting it to the motors. In his report
+Professor Riedler indicates a method by the use of which he considers
+considerable advantages may be secured. This is the heating the air in
+two stages instead of at one operation, and passing it through two
+motors, to the first of which the air is admitted heated only to a
+moderate extent; the exhaust from this motor then passes into a second
+heater and thence into the second motor. A series of experiments with
+this arrangement were recently carried out.
+
+The consumption of air per brake horse power was reduced from 812
+cubic feet per hour, a favorable duty in the single motor, to 720, and
+in the best result to 646 cubic feet with the two motors and double
+heaters. It should be added that these trials were carried out with
+steam engines but ill adapted for the purpose. It is to be regretted
+that the experiments of Professor Riedler could not have been
+conducted with more perfect appliances, but it must be borne in mind
+that the utilization of compressed air, especially as regards the
+motors, is still in a very imperfect stage, and that a great deal
+remains to be done before the maximum power available at the motor can
+be obtained. Investigations in this direction for a considerable time
+to come must be directed, therefore, toward improving the design and
+construction of the motors and the treatment of the air at the point
+of delivery into the engine.
+
+A large number of motors in use among the subscribers to the
+Compressed Air Company, of Paris, are rotary engines developing one
+horse power and less, and these in the early times of the industry
+were extravagant in their consumption, to a very high degree. To some
+extent this condition of things has been improved, chiefly by the
+addition of better regulating valves to control the air admission.
+
+As altered, the two horse power rotary motors, when employed as cold
+air engines, a method often desired in special industries, consume
+1,059 cubic feet per hour and per indicated horse power; with a
+moderate degree of heating, say to 50 deg. Cent., this consumption
+falls to 847 cubic feet. The efficiency of this type of rotary motors
+with air heated to 50 deg. may now be assumed at 43 per cent., not a
+very economical result, it is true, and one that may be largely
+improved, yet it is evident that with such an efficiency the use of
+small motors in many industries becomes possible, while in cases where
+it is necessary to have a constant supply of cold air, economy ceases
+to be a matter of the first importance.
+
+Some useful results were obtained with compressed air used in crank
+engines; it is to be regretted that with this, also, apologies have to
+be made for the imperfect design and construction; they were old steam
+engines, some of those of two horse power losing from 25 to 30 per
+cent. by their own friction; some of the others tried, however, were
+far better, a newer type losing only from 8 to 10 per cent., while the
+80 horse power referred to below showed an efficiency of 91 per cent.
+From these trials Prof. Riedler deduces--assuming 85 per cent.
+efficiency--a consumption of 611, 752, and 720 cubic feet per brake
+horse power. It is very evident from the foregoing that the Compressed
+Air Company, of Paris, will never do itself justice until as much
+thought and care has been devoted to the economical use of the motive
+power as has been expended in the means of producing it, and Professor
+Riedler's recent investigations should be especially useful in this
+respect. The question has indeed attracted the attention of more than
+one manufacturer, and reference is made to a particular type of small
+rotary motors which are being constructed by MM. Riedinger & Co., and
+which is stated have given very excellent results. These engines were
+specially used for working sewing machines and developed on the brake
+an efficiency of 34.07 and 51.63 foot pounds per second. Trials were
+made with a half horse power variable expansion Riedinger engine.
+
+
+  TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
+ ______________________________________________________________
+                                               |       |
+  Number of trials.                            |   I.  |   II.
+ ______________________________________________|_______|_______
+                                               |       |
+ Initial air pressure.     lb. per square inch |    86 | 71.8
+      "      temperature.           deg. Cent. |   +12 |  +170
+ Ft. pounds per second  measured on the brake. | 51.63 | 34.07
+ Revolutions per minute.                       |   384 |  300
+ Consumption of air for one horse power per    |       |
+    hour.                                      | 1,377 |  988
+ ______________________________________________|_______|_______
+
+
+  TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
+ _____________________________________________________________________
+                                           |      |      |      |
+  Number of trials.                        |  I.  |  II. | III. |  IV.
+ __________________________________________|______|______|______|_____
+                                           |      |      |      |
+ Initial pressure of air.  lb. per sq. in. |   54 | 69.7 |   85 | 71.8
+      "  temperature of air.    deg. Cent. |  170 |  180 |  198 |    8
+ Final        "        "            "      |   25 |   20 |  ... |   25
+ Revolutions per minute.                   |  335 |  350 |  310 |  243
+ Foot pounds per second measured on        |      |      |      |
+    brake.                                 |  271 |  477 |  376 |  316
+ Consumption of air per horse power        |      |      |      |
+    and per hour.                          |  883 |  791 |  900 |1,148
+ __________________________________________|______|______|______|______
+
+  TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
+ ___________________________________________________________________
+                  | R p  |      |                  |
+                  | e e  | I    |                  | Consumption of
+                  | v r  | n    |   Temperature    |  air per horse
+                  | o    | d h p|      of air.     |  power and per
+                  | l m  | i o o|                  |      hour.
+                  | u i  | c r w|__________________|________________
+                  | t n  | a s e|         |        |       |
+    Motor.        | i u  | t e r|Admission|Exhaust.|Nominal| Brake
+                  | o t  | e   .|         |        | horse | horse
+                  | n e  | d    |         |        | power.| power.
+ _________________|_s_.__|______|_________|________|_______|________
+                  |      |      |  deg. C | deg. C |       |
+ Nominal 80 horse | 54.3 | 72.3 |    129  |   21   |  469  |  517
+ power single     | 54.3 | 72.3 |    152  |   29   |  437  |  475
+ cylinder Farcot  | 54.0 | 72.3 |    160  |   35   |  424  |  465
+ engine.          | 40   | 65.0 |    170  |   49   |  438  |  477
+ _________________|______|______|_________|________|_______|________
+
+
+These motors, it may be assumed, represent the best practice that has
+been obtained up to the present time in the construction of compressed
+air motors; with the smallest of them, indicating about one-tenth of a
+horse power, the consumption of air, when admitted cold, was 1377
+cubic feet and 988 cubic feet when the air was heated before
+admission. The half horse power engine consumed 1148 cubic feet of
+cold air, and of heated air 791 cubic feet per horse power and per
+hour. It should be mentioned that these, the most valuable and
+suggestive of all the trials carried out by Professor Riedler, were
+conducted with the greatest care, two distinct modes of measuring the
+air supplied being followed on two occasions for each test; it may
+therefore be considered that the results given are absolutely correct.
+The trials were made with an old single cylinder Farcot engine,
+nominally of 80 horse power, but indicating over 72.3. With this
+engine the consumption of air varied from 465 to 517 cubic feet, the
+larger consumption being due to the lower temperature (129 deg. Cent.)
+to which the air was raised before admission; in the most economical
+result the temperature was 160 deg. Cent. The volumes of air referred
+to are, of course, in all cases taken at atmospheric pressure.
+
+Among the important losses that have to be reckoned with in every
+system of distributing motive power from a central station--whether by
+steam or by electricity, water, or compressed air--losses must occur
+in the mains by which the power generated is transferred from the
+point of production to that of consumption. In the case we are now
+considering very careful tests were conducted in 1889 by Professor
+Kennedy, to whose report we have already referred. Since that time
+important changes have been made by the Compressed Air Company, at
+Paris, in the details of distribution, and on this account the later
+investigations of Professor Riedler on the losses due to this cause
+are of special interest.
+
+Before its admission into the mains a certain loss occurs at the St.
+Fargeau station, in the large reservoirs to which the air is delivered
+from the compressors. This question of preliminary storage was one
+that received considerable attention when the designs of the new
+station on the Quai de la Gare were being considered. It was intended
+to construct very large receivers in the basement of the station, and
+the foundations for these were even commenced. It was decided,
+however, that for the 10,000 horse power which is to form the first
+section of the new station, and for which the complete system of mains
+has already been laid down, storage reservoirs would be unnecessary,
+and a saving both in first cost and subsequent loss of air would be
+effected. The length of mains of 19.69 in. diameter is so considerable
+that they will contain at all times a sufficient reserve of air to
+prevent any irregularities in pressure at the motors.
+
+With reference to these mains it may be mentioned that, unlike the
+11.81 in. conductors of the St. Fargeau system, of which 17 kilometers
+are laid in the Paris subways, the new mains are entirely laid in the
+streets, it having been found impossible to make room for these large
+pipes in the subways already crowded with telegraph and telephone
+wires, water mains, etc.
+
+Professor Riedler investigated the two causes of loss in the
+mains--leakage and resistance. It was superficially evident that the
+mains of the old system were so well laid, and the joints so well
+designed, that the loss from leakage was never a serious one. In
+order, however, to ascertain the amount accurately, a series of
+careful experiments were carried out by Professor Gutermuth with the
+11.81 in. mains of the St. Fargeau system.
+
+
+  EXPERIMENTS ON LEAKAGE IN MAINS.
+
+---------------------------------------------------------------------
+| |                 |         |               |             | L P A |
+| |                 |         | Air Pressure  |   Loss of   | o e i |
+| |                 |         |  in Mains.    |  Pressure.  | s r r |
+| |                 |         |---------------|-------------| s     |
+| |                 |         |  B    |       |      |      |   C D |
+| |System of Mains  | Length. |  e   T|       |      |      | o e e |
+|N|    Tried.       |         |  g   r|  At   |      |      | f n l |
+|u|                 |         |A i o i| End   |During| Per  |   t i |
+|m|                 |         |t n f a|  of   |Trials|Hour. | A . v |
+|b|                 |         |  n   l|Trials.|      |      | i   e |
+|e|                 |         |  i   s|       |      |      | r o r |
+|r|                 |         |  n   .|       |      |      |   f e |
+| |                 |         |  g    |       |      |      |     d |
+--+-----------------+---------+-------+-------+------+------+-------|
+| |                 | yards.  | atm.  |  atm. |      |      |       |
+|1|Southern reseau  |         |       |       |      |      |       |
+| | to Place de la  |         |       |       |      |      |       |
+| | Concorde.       |  9,980  | 6.5   |  6.0  | 0.5  | 1.5  |  3    |
+|2| Total reseau    | 18,500  | 6.9   |  5.9  | 1.0  | 1.5  |  6.3  |
+|3|To Place de      |         |       |       |      |      |       |
+| | la Concorde     |  9,980  | 7.0   |  6.43 | 0.57 | 0.75 |  2.16 |
+|4|Total reseau     | 18,500  | 6.7   |  5.28 | 0.88 | 1.32 |  5.5  |
+|5|Northern reseau  |         |       |       |      |      |       |
+| | to Rue de Belle-|         |       |       |      |      |       |
+| | ville.          |  1,530  | 6.0   |  5.0  | 1.0  | 0.6  |  2.3  |
+|6|To the Rue des   |         |       |       |      |      |       |
+| | Pyrenees.       |    600  | 6.1   |  3.7  | 2.4  | 0.56 |  2.2  |
+---------------------------------------------------------------------
+
+
+These trials refer to the mains running from the St. Fargeau station
+to the Place de la Concorde, a length of 9.142 kilometers; to the
+whole system of mains, 16.5 kilometers; to the northern mains running
+from St. Fargeau to the Rue de Belleville, 1.4 kilometers; and from
+St. Fargeau to the Rue des Pyrenees, 6.5 kilometers. It will be seen
+from the figures given in the table that the actual loss is small, and
+it is stated that this is due chiefly to the elastic joint employed
+throughout the system, excepting in the Rue de Belleville, where rigid
+couplings are used, and continual trouble is experienced from loss by
+leakage. In all cases the losses given are the maximum, which only
+occur under the most unfavorable conditions.
+
+It was found, during the first, second, and fourth tests, that
+considerable leakage occurred between the St. Fargeau central station
+and the Rue de Belleville. During the trials two and four, an
+uncertain amount of loss occurred from the consumption of air required
+to work the pneumatic clocks, and also motors in the circuit, that
+could not be stopped. The tests two and four include all losses in the
+service pipes, as well as the mains.
+
+The production of compressed air at the central station is assumed at
+30,000 cubic feet per hour (atmospheric pressure), and in all cases
+the loss in the mains is taken as a percentage of the total
+production.
+
+The losses due to resistance in the mains were also examined with
+great care, over independent sections, as well as through the complete
+_réseau_. During the early part of these trials, an unusual and
+excessive loss was recorded, the cause of which could not be at first
+ascertained. At intervals along these mains are placed a number of
+water reservoirs which receive the water injected into the mains; in
+addition to these the direct flow of the air is interrupted by
+numerous siphons, the stop valves to branches, etc. Investigation
+showed that the presence of these reservoirs created considerable
+resistance on account of an increased and subsequently reduced
+section. The exact loss from this cause was, therefore, carefully
+measured, as well as the losses existing in the mains not so
+interrupted. The results show that the loss by expansion at one
+reservoir, when the speed of the air flow was 23 ft. per second, was
+equal to 0.15 atmosphere; with a speed of 29 ft. 6 in. per second, it
+amounted to 0.2 atmosphere.
+
+Therefore, the presence of five such reservoirs would cause a loss in
+pressure equal to one atmosphere. This very undesirable arrangement is
+not repeated in the new system, the sumphs being connected in such a
+way as not to modify the section of the tube, nor consequently the
+pressure of the air. The presence of the siphons and stop valves did
+not seem to affect the pressure to any measurable extent. The
+following table contains a list of the more important mains tested,
+and it may be mentioned that the resistance, due to the reservoirs,
+was at first partially included. The trials were carried out while the
+mains were not being drawn upon by subscribers.
+
+
+-----------------------------------------------------------------------
+                                                   |            |
+Section of Mains Tested.                           |  Length.   |No. of
+                                                   |            |Tests.
+                                                   |            |
+---------------------------------------------------+------------+------
+                                                   |  yards.    |
+From the central station to the end of reseau and  |            |
+  back to central station by return circuit        |  18,100    |   7
+From the central station to the Rue Fontaine au    |\ 14,600    |/  3
+  Roi                                              |/  9,900    |\  4
+From the central station to the Rue de la          |            |
+  Charonne                                         |   9,490    |   5
+From the Rue de la Charonne to Fontaine au         |            |
+  Roi                                              |   4,770    |   3
+From the central station to the Avenue de la       |            |
+  Republique                                       |   1,860    |   8
+Various trials on different lengths of mains       |770 to 8,000|  11
+-----------------------------------------------------------------------
+
+
+Over the whole system of 16.5 kilometers, which was also tested when
+no air was being taken off, there were four reservoirs of considerable
+size, and which offered a large resistance with a corresponding loss
+of pressure; on the line there were also 23 siphons and 42 stop
+valves.
+
+These trials were repeated several times to secure accuracy, and the
+speed of the air was brought to 49 ft. a second. The results obtained
+in one of these trials may be taken as an example. The main between
+the Rue St. Fargeau and the Fontaine au Roi, on which there are no
+collecting reservoirs, but three siphons and eight stop valves, gave,
+with an average speed of 21 ft. 3 in., a loss in pressure of 0.05
+atmosphere for each kilometer of main.
+
+From these experiments it would appear that, assuming a speed of 21
+ft. per second, a loss in pressure of one atmosphere would correspond
+to a distance of 20 kilometers; that is to say, a central station
+could extend its mains on all sides with a radius of 20 kilometers,
+and the motors at the ends of the lines would receive the air at a
+pressure 15 lb. less than at the central station. Professor Riedler
+states that as an actually measured result, the velocity of the air
+through the mains of the St. Fargeau system is 19 ft. 8 in. per
+second, and that the loss in pressure per kilometer is 0.07
+atmosphere. From this it follows that including the resistances due to
+the four reservoirs, and other obstructions actually existing, an
+allowance of one atmosphere loss on a 14 kilometer radius is ample. By
+increasing the initial pressure of the air, much better results can be
+obtained, and future attention in practice should be devoted to this
+point. The amount of work required to compress air does not increase
+in the same ratio as the pressure, and for this reason considerable
+economy can be effected at the first stage, and the loss in the mains
+will be reduced.
+
+Passing to another point of the same subject, Professor Riedler
+considers the best dimensions that should be given to the mains.
+Resistance decreases with an increase in the diameter of these and in
+direct ratio to their diameter; for this reason--still assuming a
+pressure corresponding to a velocity of 20 ft. per second--with a fall
+of one atmosphere, a length of 40 kilometers could be succesfully
+worked.
+
+The mains of the new _réseau_ for the Quai de la Gare station are
+19.69 in. in diameter; they are built up of steel plates riveted, and
+this Professor Riedler considers to have been a serious error on
+account of the extra resistance offered by the large number of rivet
+heads.
+
+The following may be taken as a brief summary of Professor Riedler's
+conclusions: Recent improvements in central station practice have
+resulted in an increased efficiency of about 30 per cent. in the
+compressors, but this benefit can only be realized when the new
+station is in operation. That the small and very imperfect air engines
+in use on the system give an efficiency of 50 per cent., while with
+ordinary steam engines driven by air an efficiency of 80 per cent. can
+be reached with a very small expenditure of fuel for heating the air
+before admitting it into the motor. That special attention should be
+given to the improvement of air engines, and that with increased
+initial pressures at the central station the distance of the
+transmission can be very considerably augmented. Finally, Professor
+Riedler claims that power can be transmitted by compressed air more
+conveniently and more economically than by any other means.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12810.]
+
+
+
+
+THE BUILDERS OF THE STEAM ENGINE--THE FOUNDERS OF MODERN INDUSTRIES
+AND NATIONS.[1]
+
+[Footnote 1: An address delivered at the Centennial Celebration of the
+American Patent System, Washington, April, 1891.]
+
+By Dr. R.H. THURSTON, Director of Sibley College, Cornell University.
+
+
+Papin, Worcester, Savery, were the authors of the period of
+application of the power of steam to useful work in our later days.
+The world was, in their time, just waking into a new life under the
+stimulus of a new freedom that, from the time of Shakespeare, of
+Newton, and of Gilbert, the physicist, has steadily become wider,
+higher, and more fruitful year by year. All the modern sciences and
+all the modern arts had their reawakening with the seventeenth
+century. Every aspect of freedom for humanity came into view in those
+days of a new birth. Both the possibility of the introduction of new
+sciences and of new arts and the power of utilizing all new
+intellectual and physical forces came together. The steam engine could
+not earlier have taken form, and, taking form, it could not have
+promoted the advance of civilization in the earlier centuries. The
+invention becoming possible of development and application, the
+promotion of the arts and of all forms of human activity became a
+possible consequence of its final successful introduction into the
+rude arts that it was to so effectively promote and improve.
+
+But the work of these inventors was in itself but little more
+important than that of the Greek inventor of the steam ælopile, for
+each brought forward a machine which was, from a business point of
+view, utterly impracticable, and which, in each case, only served to
+show that a better device might prove useful and lead the way to its
+introduction. The merit of the inventors of the eighteenth century was
+that they were _able_ to lead the way, to point out the path to
+success, to furnish evidence of the value of the coming, crowning
+invention. The "fire engines," as they were then called, of these now
+famous men were merely contrivances by the use of which the pressure
+of confined steam of high tension could be brought to act on the
+surface of a mass of confined water, forcing it downward into pipes
+through which it was led off and upward to a higher level; and thus a
+mine could be drained, ineffectively and expensively to be sure, but
+vastly more satisfactorily than by the animal power of the time. The
+machine of Savery was the best of all; but that was only a somewhat
+improved and manageable rearrangement of the engines of Papin and
+Worcester. And, after all, Papin, the greatest man of science perhaps
+of his time, died in poverty; Worcester languished in prison his whole
+life, and the later efforts of his widow brought nothing by way of a
+return for his invention; nor did either they or their successor,
+Morland, make the introduction of the engine either general or
+remunerative.
+
+Savery, coming on the stage at more nearly the right time to seize
+upon an opportunity, gained more than either of his predecessors; but
+we have no evidence that he ever acquired any large compensation or
+met with any remarkable business success in the introduction of the
+rude engine which bore his name; nor did Desaguliers, the great
+philosopher, or even Smeaton, the great engineer, of the later years
+of that century, make any great success of it. It was reserved for
+Watt to reap the harvest. But, though he so effectively reaped where
+his predecessors had sown, Watt is not the greatest of the inventors
+of the steam engine, if we rate his standing by the magnitude of the
+improvement which marked his reconstruction of the engine.
+
+It was NEWCOMEN who made the modern steam engine.
+
+When Newcomen came forward the labors of Worcester in Great Britain
+had sufficed to attract the attention of all intelligent men to the
+character of the problem to be solved, and to convince them of its
+importance and promise. The work of Savery had shown the
+practicability of the solution of the problem, both in mechanics and
+finance. He succeeded, though under great disadvantages and
+comparatively inefficiently. Once the task had been performed, though
+ever so rudely, the rest came easily and promptly. The defects of the
+Savery system were at once recognized; its great wastes of heat and of
+steam were noted, and the fact that they were inherent in the system
+itself was perceived. A complete change of type of machine was
+obviously requisite; it was this which constituted the greatest
+invention in the whole history of the steam engine, from Hero's time
+to our own; and to Newcomen we owe more than to any other man who ever
+lived, the value of the invention itself being considered, and the
+importance of the services of its introducer being left out of
+consideration. No such complete and vital improvement and modification
+of the machine has ever been effected by any other man, Watt and
+Corliss not excepted. Newcomen and his comrade Calley--we do not know
+how the honors should be divided--produced the modern steam engine.
+Its predecessor, the Savery engine, had been a mere steam "squirt."
+Newcomen constructed an engine. Savery built a simple combination of
+cylindrical or ellipsoidal vessels which wastefully and at once
+performed all the several offices of engine, pump, condenser, and
+boiler; Newcomen divided the several elements among as many parts,
+each especially adapted to the performance of its task in the most
+effective manner--the condenser excepted; for that was Watt's
+principal invention--and thus produced the first steam engine in the
+modern sense of that term.
+
+It was Newcomen, not Watt, who gave us the train of mechanism that we
+now call the steam engine. It is to Newcomen, rather than Watt, that
+we owe the highest honors as an inventor in this series of the most
+important of all the products of the inventive genius of mankind.
+Newcomen brought into existence a new, the modern, type of engine, and
+effected the greatest revolution that has been recorded in the history
+of the arts. Without Newcomen, there might have been no Watt; without
+Watt, there very possibly may not even yet have been brought into
+existence that giant of our time, whose mighty powers are employed
+more effectively than ever those of Aladdin's genii, in building
+palaces, in transporting men and material, in doing the work of the
+whole world; promoting the welfare of the race, in a single century,
+more than had all the forces of matter and mind together in the whole
+previous history of the world. Newcomen laid down a foundation beneath
+our whole economic system, out of sight, almost, but the essential
+base, nevertheless, on which Watt and his successors have carried up
+the great superstructure which seems to us to-day so imposing; which
+is so tremendous in magnitude, importance, and result. If to any one
+man could be assigned the credit, it is Newcomen who is to be
+considered the inventor of the steam engine.
+
+James Watt, indisputably the great inventor that he was, found the
+steam engine ready to his hand, applied himself to its improvement,
+and made it substantially what it is to-day. His most important work,
+the most unique service performed by him, was, however, that of its
+adaptation and introduction to do the work of the world. James Watt
+was the inaugurator of the era of refinement of the machine already
+invented, and the greatest of its builders and distributors. His
+inventions were all directed to the improvement of its details, and
+his labors to its introduction and its application to the myriad tasks
+awaiting it. By the hands of Watt it was made to pump water, to spin,
+to weave, to drive every mill; and he it was who gave it the form
+demanded by Stephenson, by Fulton, by the whole industrial world, for
+use on railway and steamboat, and in mill and factory, throughout the
+civilized countries of the globe. It was this great mechanic who
+showed how it might be made to do its work with least expense, with
+highest efficiency, with greatest regularity, with utmost
+concentration of power.
+
+The grand secret of his success was historical and economic, as much
+as scientific and mechanical. He brought out his inventions just when
+the world was economically and historically ready for them. The age of
+authority was past, that of freedom was come; the period of political
+and ecclesiastical tyranny was gone by, and that of the spontaneous
+development of man was arrived. The great invention was offered to a
+world ready and needing it, and, more than all, competent, for the
+first time in history, to make and use it.
+
+James Watt was himself a product of the modern scientific spirit. He
+was a man so constituted mentally that he could apply scientific
+methods to problems which his logical and clairvoyant mind could
+readily and exactly formulate the instant he was led to their
+consideration in the natural course of his progress. He was the ideal
+great inventor and mechanic. With inventive genius he combined strong
+common sense--not always a quality distinguishing the inventor--clear
+perception, breadth of view, and scientific method and spirit in the
+treatment of every question. His natural talent was re-enforced by an
+experience and an environment which led him to develop these ways and
+this mental habit. His trade was that of an instrument maker, his
+position was that of custodian and repairer of the apparatus of
+Glasgow University. He had for his daily companions and stimulus the
+great men and ozonized atmosphere of that famous institution. He kept
+pace with advancing science, and was imbued, both naturally and
+through contact with its promoters, with that ambition and those
+aspirations which are the life element of all progress, whether
+scientific or other. He was aware of the nature of the problems
+seeking solution at the time, and familiar with the state of his own
+art and that of the great mechanicians about him. Everything was
+favorable to his progress, so soon as he should be given an
+opportunity to take a step in advance and to come into sight at the
+front. The man and the time were both ready, and all conditions,
+internal and external, social and personal, were favorable to his
+development.
+
+The invention upon which Watt was to improve was at his hand. A word
+in regard to its status at the moment will throw some light upon that
+of Watt and his creation. Newcomen had, as we have seen, produced the
+modern type of steam engine as an original and wholly novel invention.
+But this machine, marvelous as an advance upon pre-existing forms of
+the steam engine, was still, as seen in the light of recent knowledge
+and experience, exceedingly defective. The purpose of a steam engine
+is to convert into usefully applicable power the hidden energy of
+fuel, stored ages ago in the earth, by transformation, through the
+action of vegetation, from the original form, the heat of the sun,
+into an available form for reconversion, through thermodynamic
+operations. In this process of reconversion, whatever the nature of
+the machine used in the operation, there are invariably wastes, both
+of heat required for conversion into power and of the power thus
+produced. That machine which effects the most complete transmutation
+of the heat supplied it into mechanical power, which wastes the least
+amount of heat supplied and of power produced, is the best engine, and
+constitutes an advance over every other.
+
+It was this reduction of wastes that made the Newcomen engine so much
+superior to that of Savery. The latter was by far the simpler and less
+costly construction; but its enormous losses, both of heat and of
+power, mainly the former, however, made it an extravagant expenditure
+of money to buy and use it. The Newcomen engine, costly and cumbrous,
+comparatively, nevertheless wasted so much less heat and steam and
+fuel that no one could afford to buy the cheaper machine. Before
+considering what Watt accomplished, we may find it profitable to
+examine into the nature of the wastes which characterized this later
+and better machine on which he effected his improvements.
+
+The Newcomen engine consisted of a steam boiler, a steam cylinder, a
+beam and a set of pumps. By making the boiler do its work separately,
+the engine acting independently, and the pumps as a detached portion
+of the mechanism, this inventor had reduced to an enormous extent
+those wastes of heat and of steam and of fuel which were unavoidable
+in the older machines in which all these parts were represented by a
+single vessel, or by two at most, in each element. In the Savery
+engine, the steam entering first heated up the interior of the working
+vessel to its own temperature, and held it at that temperature in
+spite of the cooling influence of the water present. This consumed
+large quantities of heat. It then was compelled to surrender probably
+much greater quantities still to the water itself, coming in direct
+contact as it did with its surface. If the water was agitated, either
+by the currents produced during its ingress or by the impact of the
+steam entering the vessel, this heating action penetrated to
+considerable depths and perhaps even warmed the whole mass very far
+above its initial temperature. This constituted another and a very
+serious loss. Then, again, as the water was gradually driven out of
+the containing vessel by the steam pressing on its surface, new
+portions of the vessel and new masses of water were continually
+brought in contact with the hot steam, taking its full temperature,
+and thus, often, probably, finally heating the whole mass of the
+forcing vessel, and a large proportion of the water as well, up to the
+temperature, approximately at least, of the steam itself. Thus in many
+instances, if not always, vastly more heat and steam were wasted, in
+this undesirable heating of water and forcing vessel, than were
+usefully employed in the legitimate work of raising the water to a
+higher level. In fact, in some cases in which these quantities were
+measured, the wastes were one hundred times as much as the work done.
+One per cent. of the heat supplied did the work; while ninety-nine per
+cent. was thrown away. One dollar or one shilling expended for fuel to
+do the work was accompanied by an expenditure of ninety-nine dollars
+or shillings thrown away, because of the imperfections of the system
+and machine. The whole history of the development of the steam engine
+has been one of gradual reduction of these wastes; until to-day, our
+best engines only compel us to spend five dollars for wastes to each
+dollar paid out for useful work. A business man would think that amply
+extravagant, however, and the man of science is continually seeking
+methods of evading these losses, a large proportion of which are now
+apparently unavoidable in heat engines, by finding some new system of
+heat and energy transformation.
+
+Watt was the instrument maker and repairer at Glasgow University in
+the year 1763. His companions were, among others, the professors of
+natural philosophy and of mathematics in the university. Their
+conversation and their frequent presentation of practical and
+scientific questions and problems stimulated his naturally inquiring
+and inventive mind to the pursuit of a thousand interesting and
+promising schemes for the improvement of existing methods and
+machinery. Dr. Robison, then a student, suggested the invention of a
+steam carriage for use on common roads, and the young mechanician at
+once began experiments that, resulting in nothing at the time, were
+nevertheless continued, in one or another form, until all modern
+applications of steam came into view. Dr. Black taught Watt chemistry,
+then a newly constructed science, and led him on to the discovery,
+finally made by them independently, of the fact and the magnitude of
+the latent heat of steam; the discovery coming of a series of
+scientifically planned and accurately conducted investigations, such
+as the man of science of to-day would deem creditable. The treatises
+of Desaguliers and others on physics gave Watt a knowledge of that
+domain of natural phenomena which stood him in good stead later, when
+he attempted to apply its principles to the reduction of the wastes of
+the steam engine.
+
+It was while at Glasgow University, working under such influences and
+in such an atmosphere of intellectual activity, that the accident of
+the Newcomen model engine needing repair brought to the mind of Watt
+the opportunity which, availed of at once, made him famous and gave
+the world its greatest aid, its most powerful servant. The observing
+mind of the great mechanic immediately noted its defects, sought their
+causes, found their remedy. He discovered, at once, that the quantity
+of steam entering the cylinder of the little engine has four times the
+volume of the cylinder receiving it: in other words, three-fourths of
+that steam must be condensed immediately on entrance. This meant,
+evidently, that only one-fourth of the steam supplied was utilized,
+and even then inefficiently, in doing its work. The reason of this was
+as easily seen, immediately the fact was revealed. As Watt himself
+expressed it, the causes of this loss, causes which would obviously be
+exaggerated in a small engine, were: "First, the dissipation of heat
+by the cylinder itself, which was of brass and both a good conductor
+and a good radiator. Secondly, the loss of heat consequent upon the
+necessity of cooling down the cylinder at every stroke in producing
+the vacuum. Thirdly, the loss of power due to the pressure of vapor
+beneath the piston, which was a consequence of the imperfect method of
+condensation." This much determined, the next step looked toward the
+confirmation of his conclusions and the remedy of the defects.
+
+To meet the first difficulty he made a cylinder of wood, soaked in oil
+and baked, a non-conducting and non-radiating material. Then he was
+able to determine with some accuracy the quantities of steam and
+injection water used in the engine; and a comparison with the original
+cylinder and its operation showed that not only four times the
+quantity of steam, but also four times the amount of injection water
+was used as was necessary, assuming wastes checked. Further scientific
+research on the part of Watt gave him measures of specific heats of
+the metals and of wood, the specific volumes of steam at various
+working pressures, the evaporative efficiency of boilers, the
+pressures and temperatures of steam in the boiler under specified
+conditions, the quantities of steam and of water required for the
+operation of his little condensing engine.
+
+Then came his enunciation of the grand principle of economy in the
+construction and operation of the steam engine: "Keep the cylinder as
+hot as the steam which enters it," as he expressed it. This was Watt's
+guiding principle, as it has been that of all his successors in the
+improvement of the economic performance of the steam engine and of all
+other heat engines. The great source of waste is the dispersion of
+heat, uselessly, which should be applied to the production of work by
+its transformation, thermodynamically, into the latter form of energy.
+The second form of waste is that of power thus produced in the
+unprofitable work of moving the parts of the engine itself; and the
+third is that of heat by transfer, without transformation, by
+conduction and radiation to surrounding bodies. In modern engines, the
+latter is but three or five per cent., in the best cases; the second
+waste constitutes perhaps ten per cent.; while the first of these
+losses amounts very usually to seventy per cent., of which last
+one-third or one-fourth is of the kind discovered by Watt, the rest
+being the thermodynamic waste incident to all known methods of
+operation of heat engines, and apparently unavoidable. In our very
+best and largest engines, the waste found by Watt to constitute three
+fourths of all heat supplied has been brought down to ten per cent., a
+fact which well exemplifies the advances made since his time of
+apprenticeship by himself and his successors of this nineteenth
+century. The steam engine of to-day, in its most successful operation,
+gives us twenty-five times as much power from a pound of coal as did
+the engine that the great inventor sought to improve: this is the
+magnificent fruit of that one discovery of James Watt, and of
+application of the simple principle which he so concisely and clearly
+stated.
+
+The method adopted by Watt to secure a remedy, so far as practicable,
+of this defect of the older machine was as simple and as perfect as
+was the principle which it embodied. He first removed from the
+cylinder the prime source of its wastes; providing a separate
+condenser, and thus avoiding the repeated chilling of its surfaces by
+the cold water used in condensing the steam at exhaust, and also
+permitting its strokes to be made with far greater frequency, thus
+giving less time for cooling by the influence of the remaining vapors
+after condensation. He next went still further, and provided the
+cylinder with a closed top, keeping out the air, and a "jacket" of hot
+boiler steam to _keep_ it as hot as the steam which entered it. These
+were the two great improvements which converted the first real steam
+engine into an economical form of heat engine and essentially finished
+the work so grandly begun by Newcomen and Calley. These changes gave
+us the modern steam engine; and these are Watt's first and greatest,
+but by no means only, contributions to the production of the modern
+world with all its comforts, its luxuries and its opportunities for
+material, intellectual and moral advancement of individual and of
+race. His work was to this extent complete in 1765.
+
+But Watt did not stop here. There still remained for him the no less
+important and the, in some senses, still more imposing, work of
+finding employment for the new servant of mankind and of setting it at
+its work of giving the human arm a thousand times greater strength, to
+the mind of man uncounted opportunities to promote the advancement of
+knowledge, of civilization, of every good of the race. His was still
+the task of adapting the new machine to all the purposes of modern
+industry. It had been hitherto confined to the task of raising water
+from the depths of the mine; it was now to be harnessed to the railway
+train; to be made to drive the machinery of the mill, to apply its
+marvelous power to the impulsion of the river boat and ocean steamer;
+to furnish energy, through endless systems of transfer and use, to
+every kind of work that man could devise and should invent. All this
+meant the giving of the machine forms as various as the purposes to
+which it was to be devoted. It had previously only raised and
+depressed a rod; it must now turn a shaft. It had then only operated a
+pump; it must now turn a mill, grind our grain, spin our threads,
+weave our cloths, drive our shops and factories, supply the powerful
+blast of the iron furnace. It must be made to move with the utmost
+conceivable regularity, and must, with all this, do its work in the
+development of the hidden energy of the fuel, with the greatest
+possible economy, through the expansion of its steam. All this was
+achieved by James Watt.
+
+The invention of the double-acting engine, in which the impulsion of
+the steam is felt both in driving the piston forward and in forcing it
+backward, both upward and downward, the application of its force
+through crank and fly wheel, the creation of an automatic system of
+governing its speed, and the discovery of the economy due to its
+complete expansion, were all improvements of the first magnitude, and
+of the greatest practical importance; and all these were in rapid
+succession brought into existence by the creative mind that had
+apparently been brought into the world for the express purpose of
+giving to the hand of man this mighty agent, to perfect the mightiest
+power that mind of man has yet conceived.
+
+But to do the rest required more than inventive genius and mechanical
+skill. It demanded capital and the stored energy of labor and genius
+in other fields, directed by the mind of a great "captain of
+industry." This came to Watt through Matthew Boulton, a manufacturer
+of Birmingham, whose father and ancestors had gradually and
+toilsomely, as always, accumulated the property needed for the
+prosecution of a great business. The combination of genius and capital
+is always an essential to success in such cases; and good fortune, a
+Providence, we may well say, brought together the genius and the
+capitalist to do their work, hand in hand, of providing the world with
+the steam engine. Hand in hand they worked, and all the world to-day,
+and the race throughout its future life, must testify gratitude for
+the inexpressible obligations under which these two men have placed
+them, doing the work of the world.
+
+Boulton & Watt, the capitalist with the inventor, gave the world the
+steam engine, finally, in such form and in such numbers that its
+permanent establishment as the servant of man was insured. The
+capitalist was as essential an element of success as was the inventor,
+and, in this instance, as in a thousand others, the race is indebted
+to that much-abused friend of the race, the capitalist, for much that
+it enjoys of all that it desires. The industry and patience, the skill
+and the wisdom required for the accumulation of this energy stored for
+future use in great enterprises is as important, as essential, as
+inventive power or any other form of genius. Talent and genius must
+always aid each other. This firm was established in 1764 and its main
+resources, aside from the bank account, were Watt's patent, about
+expiring, and Watt's genius, and Boulton's talent as a man of
+business. The patent was extended for twenty-four years, the new
+inventions of Watt, now beginning to pour from his prolific brain in a
+wonderful stream, were also patented, and the whole works were soon
+employed upon the construction of engines for which numerous orders
+soon began to pour in upon the now prosperous builders. The patent law
+established Boulton and Watt and the firm paid back the nation with
+handsome usury, giving it unimaginable profits indirectly through its
+control of the work of the world and large profits directly through
+the business brought them from all parts of the then civilized globe.
+There has never, in the history of the world, been a more impressive
+illustration of the value to a nation of that generous public policy,
+that simply just legislation, which gives to the man of brain control
+of the products of his mind. For a hundred years, Great Britain has,
+largely through her encouragement of the inventor and her protection
+of his mental property by securing the fruits of his labors, in fair
+portion, to him, gained the power of dictating to the world and has
+gained an advance that cannot be measured. Watt and Arkwright and
+Stephenson and Crompton and their ilk, protected by their government
+and its patent laws, made their country the peaceful conqueror of the
+world. The story of the work of the inventor is a poem of mighty
+meaning and of wonderful deeds. The inventor proved himself a mightier
+magician than ever the world had seen.
+
+    "A creature he called to wait on his will,
+    Half iron, half vapor--a dread to behold;
+    Which evermore panted, and evermore rolled,
+    And uttered his words a millionfold."
+
+Such was the outcome of this grand modern "trust," a combination of
+the wisest legislation, the most brilliant invention, and the most
+wisely applied capital. There are "trusts" of which the outcome is
+most beneficent.
+
+Since the days of Watt, the improvement of the steam engine and the
+work of inventors has been confined to matters of detail. All the
+fundamental principles were developed by Watt and his predecessors and
+contemporaries and it only was left to his successors to find the best
+ways of carrying them into effect. But these matters of detail have
+been found to involve opportunities to make enormous strides in the
+direction of securing improved efficiency of the machine. The further
+application of the principle which led Watt to his greatest
+inventions; of the principle, keep the cylinder as hot as the steam
+which enters it, of that which he enunciated relative to the advantage
+of expanding steam, and of that affecting the regulation of the
+machine; have reduced the costs of steam and of fuel to a small
+fraction of their earlier magnitude. One ton of engine to-day does the
+work of eight or ten in the time of Watt: one pound of fuel or of
+steam gives to-day ten times the power then obtained from it. A
+steamship now crosses the Atlantic in one-eighth the time required by
+the famous "liner" of the "Black Ball Line." The wastes of the engine
+have been brought down from above eighty per cent. to eight; and a
+half-ounce of fuel on board ship will now transport a ton of cargo
+over a mile of ocean.
+
+FREDERICK E. SICKELS gave us the first practicable form of expansion
+gear in 1841; GEORGE H. CORLISS gave a new type of engine of marvelous
+perfection and economy in 1849; Noble T. Green, Wm. Wright and many
+less well known but no less meritorious inventors have since done
+their part in the transformation of the old engine of Watt into the
+modern wonder of concentrated and economical power, and marvel of
+accurate and beautiful design and workmanship. The "trip cut-off,"
+with reduced clearances, increased boiler pressure, higher rates of
+expansion, accelerated speeds of engine, better construction in all
+respects, as well as improved design, have enabled us to avail
+ourselves to the utmost of the principles of Watt, and our mills, our
+railways, our steamers and our fields, even, have gained almost as
+extraordinarily by these advances, since the days of the great
+inventor, as through his immediate labors.
+
+With the introduction of the new form of older energy, electricity,
+with the reduction of the lightning into thraldom, has now come a new
+impulse affecting all the industries. Through its mysterious, its
+still unknown action, steam now reaches out far from its own place,
+driving the electric car along miles of rail; giving light throughout
+all the country about it, turning night into day, and repressing crime
+while encouraging legitimate labor, reaching into distant chambers and
+every little workshop, to offer its powerful aid in all the
+distributed work of cities. Without the steam engine there would be
+little work available for electricity, but the appearance of this, the
+latest and most useful handmaid of steam, has given the engine work to
+do in an uncounted number of new fields, has called in the inventor
+once more to adapt steam to its new work. The "high-speed engine" is
+the latest form of the universal helper. And such has been the
+readiness and the intelligence of the contemporary inventor that we
+now have engines capable of turning their shafts three hundred
+rotations a minute and without a perceptible variation of velocity,
+whatever the change of load or the suddenness with which it is varied.
+In the days of Watt a fluctuation of five per cent. in speed was
+thought wonderfully small; in those of Corliss, the variation was
+restricted to two per cent. and we wondered at this unanticipated
+success. To-day, thanks to Porter and Allen, to Hartnell, to Hoadley,
+to Sims, to Thomson, to Sweet, to Ide, and to Ball, we have seen the
+speed fluctuation restricted to even less than one per cent. of its
+normal average.
+
+The inventors of the steam engine are, through their representatives
+of to-day, according to the statisticians, doing the equivalent of
+twelve times the work of a horse, for every man, woman and child on
+the globe. We have not less, probably, than a half million of miles of
+railway, transporting something over 150,000,000,000 of tons a mile a
+year. A horse is reckoned to haul a ton weight about six and a half
+miles, day by day, by the year together. In the United States, it is
+reckoned that the steam engine, on the railways alone, hauls a
+thousand tons one mile, for every inhabitant of the country, every
+year, or, if it is preferred to so state it, a ton a thousand miles.
+This is the way in which the East and the West are, by the inventors
+of the steam engine, enabled to help each other. This costs about $10
+each individual; it would require some 25 millions of horses to do the
+work, and would cost about $1,000 a family, which is more than twice
+the average family earnings.
+
+Dr. Strong, in that remarkable book, "Our Country," says: "One man, by
+the aid of steam, is able to do the work which required two hundred
+and fifty men at the beginning of the century. The machinery of
+Massachusetts alone represents the labor of more than 100,000,000 men,
+as if one-half of all the workmen of the globe had engaged in her
+service." And again: "Some thirty years ago, the power of machinery in
+the mills of Great Britain was estimated to be equal to 600,000,000
+men, or more than all the adults, male and female, of all mankind."
+Mr. Gladstone estimated that the aggregation of wealth on the globe
+during the whole period from the birth of Christ to that of Watt was
+equaled by the production in twenty years, at the middle of this
+century, with the aid of machinery driven by the fruit of the brain of
+the inventors of the steam engine. We may probably now safely estimate
+the former quantity as rivaled in less than five years, while, since
+the birth of Watt and his engine, and the production of the spinning
+mule, the power loom, the cotton gin and our own patent system and its
+marvelous mechanism, all events of a century ago, we may estimate that
+they have, together, accomplished more in this period which we now
+celebrate than could have been done in a millenium of milleniums
+without these now subjected genii. But the power behind all these
+curious inventions and their work is that of steam. The steam engine
+even supplies power to the telegraph and transports words and thought
+as well as cotton bales and coal.
+
+And now what has this combination of legislation for private
+protection and public good, of a genius producing great inventions,
+and of the accumulated capital of earlier years, brought about?
+
+It has given us the best fruits of science in permanent possession.
+The study of science invariably aids, in a thousand ways, the progress
+of mankind. It gives us new conceptions of nature and of the
+possibilities of art; it promotes right ways of work and of study; it
+teaches the inventor and the discoverer how most surely and promptly
+to gain their several ends, it gives the world the results of all
+acquired knowledge in concrete form. This one instance which we are
+now especially interested in contemplating has performed more
+wonderful miracles than ever Aladdin's genii attempted. One man, with
+a steam engine at his hand, turns the wheels of a great mill, drives
+forty thousand spindles, applies a thousand horse power to daily work
+in the spinning of threads, the weaving of cloth, the impulsion of a
+steamboat, or the drawing of great masses of hot iron into finest
+wire. This puny creature, his mind in his finger tips, exerts the
+power of ten thousand men, working with muscle alone, and, aided by a
+handful of women, boys and girls, clothes a city. A half dozen men in
+the engine room of an ocean steamer, with a hundred strong laborers in
+the boiler room and on deck, transports colonies and makes new
+nations, brings separated peoples together, unites countries on
+opposite sides of the globe, brings about easy exchanges between pole
+and equator. One man on the footboard of the locomotive, one man
+shoveling into the furnaces the black powder that incloses the energy
+stored in early geological ages, a half dozen men mounted on the long
+train of following vehicles, combine to bring to the mill girl in
+Massachusetts, the miner in Pennsylvania, the sewing woman, and the
+wealthy merchant, her neighbor in New York, the flour made in
+Minnesota from the grain harvested a few weeks earlier in Dakota. All
+the world is served faithfully and efficiently by this unimaginable
+power, this product of the brain of the inventor, protected by the
+law, stimulated and aided by the capital that it has itself almost
+alone produced.
+
+And thus have the inventors of the steam engine set in motion and
+placed at the disposal of mankind for every form of useful work all
+the great forces of nature; thus Hero of Alexandria touched the then
+concealed spring which called all the genii of earth, fire, water and
+air to do the bidding of the race. Thus Papin, Worcester, Newcomen,
+Watt, and Corliss and others of our own contemporaries, have applied
+the genii to their task of leveling mountains, traversing seas,
+continents, and the depths of the earth, building ships, locomotives,
+hamlets and cities, cottages and palaces, turning the spindle,
+operating the loom, and setting motion and giving energy to every
+machine, doing the work of thousands of millions of men, converting
+barbarism into civilization, giving necessaries of life in profusion,
+comforts in plenty, and luxuries in superabundance.
+
+Aiding and working hand in hand with those other genii of progress,
+the inventors of the printing press and of the telegraph, the
+telephone, and the electric railway, of the modern system of textile
+manufactures, of iron and steel making, of the mowing machine and the
+harvester, they have compressed into two centuries the progress of a
+millennium, destitute of their aid. Every step taken under their
+stimulus, and with their help, is a step toward a higher life for all,
+intellectually and morally as well as physically; every advance in the
+improvement of their work is a gain to every man, woman, and child;
+every improvement of the steam engine is a help to the whole world.
+This progress makes the day of the extinction of the system now
+grinding the populations of the earth into the ground, the day of the
+abolition of armies and the restoration to the people of that freedom
+which characterized the times of the patriarchs, and of the
+restoration of the rights of the citizen to his own time and strength
+and producing power, perceptibly nearer.
+
+When this final revolution shall have been accomplished, and when all
+the world has settled down to the steady and undisturbed work of
+production by daily and regular labor, aided by the genii of steam, of
+electricity, of all nature, combined for good, the results of the
+intellectual activity of the inventors of the steam engine will be
+fully seen. Then no monument will be required to keep green the memory
+of Watt, Corliss, or any other of these great men, but it will be said
+of them, as of Sir Christopher Wren in the epitaph in St. Paul's:
+"Seek you a monument, look about you!" Every wreath of steam rising to
+the heavens from factory, mill or workshop will be a reminder of Hero
+of Alexandria, every mine will possess a memorial to Papin, Worcester
+and Savery; every steamship will bring into grateful memory Fitch and
+Stevens, and Bell and Fulton; thousands of locomotives, crossing the
+continents, will perpetuate the thought of the Stephensons and their
+colleagues in the introduction of the railway; the hum of millions of
+spindles and the music of the electric wire will tell of the work of
+Corliss and his contemporaries and successors who made these things
+possible, and all kingdoms and races, all nations, will revere the
+name of James Watt, the genius to whom the world is most indebted for
+the beginnings of all this later and grander civilization which has
+converted the slow progress of earlier centuries into the meteor-like
+advance of to-day toward a future as grand and as mighty and as noble
+as humanity shall choose to make it.
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED HAND CAR.
+
+
+[Illustration]
+
+In the accompanying illustration we show a new design of hand car,
+being introduced by the Courtright Manufacturing Co., of Detroit. It
+will be seen that the apparatus for propelling the car is very
+different from the mechanism generally used. An upright framework
+secured to the platform carries a large sprocket wheel, which is
+connected to a smaller one upon one of the axles by means of a chain.
+The larger sprocket wheel is rotated by means of a triangular shaped
+lever attached at the lower corner to the crank of the sprocket wheel
+and having a handle at each of its upper corners. It is hinged upon a
+fulcrum which slides upon the two vertical rods shown in the
+illustration. It will be seen that this gives a peculiar movement to
+the handles by which the operators propel the car, but it has been
+found that the motion is an excellent one, and it is claimed that a
+higher speed can be obtained with the mechanism here shown than with
+any other now in use. There is practically no dead center, as in the
+case where the ordinary crank and lever is used. A number of leading
+roads have given the car a trial, and being well satisfied it, have
+given orders for more. The company claim that a car with 20 in. wheels
+can easily be made to attain a speed of 15 miles an hour by two
+men.--_Railway Review_.
+
+       *       *       *       *       *
+
+
+
+
+THE CONIC SECTIONS.
+
+By Prof. C.W. MACCORD, Sc.D.
+
+
+In Fig. 1 let D be a given point, and O the center of a given circle,
+whose diameter is FG. Bisect DF at A. Also about D describe an arc
+with any radius DP greater than DA, and about O another arc with a
+radius OP = DP + FO, intersecting the first arc at P, then draw PD,
+and also PO, cutting the circumference of the given circle in L. Since
+PD = PL, and DA = AF, it is evident that by repeating this process we
+shall construct a curve PAR, which satisfies the condition that _every
+point in it is equally distant from a given point and from the
+circumference of a given circle_. Since PO-PD = LO, and AO-AD = FO,
+this curve is one branch of the hyperbola of which D and O are the
+foci.
+
+[Illustration: FIG. 1]
+
+Bisect DG at B, then about D describe an arc with any radius DQ
+greater than DB, and about O another are with radius OQ = DQ-FO; draw
+from Q the intersections of these arcs, the line QD, and also QO,
+producing the latter to cut the circumference in E. By this process we
+may construct the curve QBZ, each point of which is also equally
+distant from the given point D, and from the concave instead of the
+convex arc of the given circumference. The difference between QD and
+QO being constant and equal to FO, and AB being also equal to FO, this
+curve is the other branch of the same hyperbola, whose major axis is
+equal to the radius of the given circle.
+
+The tangent at P bisects the angle DPL, and is perpendicular to DL,
+which it bisects at a point I on the circumference of the circle whose
+diameter is AB, the major axis, the center being C, the middle point
+of D O. As P recedes from A, it is evident that the angles P D L, P L
+D, will increase, until D L assumes the position D T tangent to the
+given circle, when they will become right angles. P will therefore be
+infinitely remote, and the point I having then reached t, where D T
+touches the smaller circle, C t S will be an asymptote to the curve.
+This shows that the measurements from the convex arc, for the
+construction of A P, are made only from the portion F T of the given
+circumference.
+
+In the diagram the point Q is so chosen that D L produced passes
+through E, so that Q J, the tangent at Q, is parallel to P I. It will
+thus be seen that the measurements from the concave arc, for the
+construction of B Q, are confined to the portion G T of the given
+circumference. As D L E rises, the points P and Q recede from A and B,
+the points L and E approach each other, finally coinciding at T; at
+this instant I and J fall together at t, so that S S is the common
+asymptote to A P and B Q.
+
+In Fig. 2 the given point D lies within the circumference of the given
+circle. Bisect D F at A, and D G at B; about D describe an arc with
+any radius D P greater than D A, and about O another, with radius O P
+= O F--D P, these arcs intersect in P, and producing O P to cut the
+circumference in L, we have P D = P L. Similarly E D = E H, U D = U W,
+etc. And since P D + P O = L P + P O, D E + E O = H E + E O, and so
+on, the curve is obviously the ellipse of which the foci are D and O,
+and the major axis is A B = F O, the radius of the given circle.
+
+[Illustration: FIG 2.]
+
+If, as in Fig. 3, the given point be made to coincide with the center
+of the circle, the ellipse becomes a circle with diameter A B = F O.
+But if the point be placed upon the circumference, as in Fig. 4, the
+ellipse will reduce to the right line A B coinciding with F O.
+
+[Illustration: FIGS 3, 4, 5, 6.]
+
+In this case we may also apply the same process as in Fig. 1; D T
+becomes a tangent at D to the circumference, and the asymptotes
+coincide with the axis of the hyperbola, of which one branch reduces
+to the right line A P extending from A to infinity on the left, and
+the other reduces to the right line B G Q, extending from B to
+infinity on the right.
+
+If the circle be reduced to a point, as in Fig. 5, the resulting locus
+is a right line perpendicular to and bisecting D O. If on the other
+hand the diameter of the given circle be infinite, the circumference,
+as in Fig. 6, becomes a right line perpendicular to the axis at F, and
+the curve satisfies the familiar definition of the parabola, D E being
+equal to E H, D P equal to P L, and so on.
+
+In Fig. 7, as in Fig. 1, DT is tangent at T to the given circle whose
+center is O, and at t to the circle about C whose diameter is AB, the
+major axis. Since DTO is a right angle, T lies upon the circumference
+of the circle whose center is C, and diameter DO; this circle cuts the
+asymptote SCS at M and N. The semi-conjugate axis is a mean
+proportional between D A and AO; now drawing TM and TN, it is seen
+that Tt is that mean proportional; and a circle described about C with
+that radius will be tangent to TO. DT, then, is the radius of the
+circle to be described about the focus of the conjugate hyperbola for
+its construction according to the enunciation first given: and we
+observe that DT and TO are supplementary chords in the circle about C
+through D and O. The conjugate foci must therefore lie upon this
+circumference, at D' and O'; and since D'O' is perpendicular to DO,
+D'T will be perpendicular and T'O' will be parallel to SCS.
+
+[Illustration: FIG 7.]
+
+Now as TO increases, T'O' will diminish, until, when TO equals DO,
+T'O' will vanish and with it Ct'; and at this crisis, the case is the
+same as in Fig. 4; but the conjugate hyperbola logically reduces to
+_two_ right lines, extending from C to infinity on the right and left.
+As indeed it should from the familiar construction, since the
+distances from D' and O' to any point on the horizontal axis being
+equal, their difference is constant and equal to zero.
+
+It appears, then, that a conic section may be defined as the locus of
+a point which is equally distant from a given point and from the
+circumference of a given circle. Boscovich defines it as the locus of
+a point so moving that its distances from a given point and from a
+given right line shall have a constant ratio.
+
+The latter definition involves the conceptions of a rectilinear
+directrix, and a varying ratio in the cases of the different curves,
+this ratio being unity for the parabola, less for the ellipse, and
+greater for the hyperbola. The former involves the conception of a
+circular directrix with a ratio equal to unity in all cases; and the
+two definitions become identical in the construction of the parabola,
+which is in fact the only curve of which a clear idea is given by
+either of them. That of Boscovich has been given a prominence far in
+excess of its merits, being made the foundation for the discussion of
+these important curves, and this in a textbook whose preface contains
+the following true and emphatic statement, viz.:
+
+    "The abstract nature of a ratio, and the fact that it is a
+    compound concept, peculiarly unfit it for elementary
+    purposes."
+
+The definition herein set forth has not been given in any treatise on
+the subject, so far as we have been able to ascertain. And it is
+presented with the distinctly expressed hope that it never will be,
+except as a mere matter of abstract interest.
+
+Of this it may, like the other, possess a little, but both have the
+great disadvantage that, except in relation to the parabola, the idea
+which they convey to the mind of the curves to which they relate, if
+indeed they convey any at all, is most obscure and indirect; and of
+practical utility neither one can claim a particle.
+
+       *       *       *       *       *
+
+
+
+
+TABLE OF ATOMIC WEIGHTS.
+
+(Issued December 6, 1890.)
+
+
+By request of the Committee of Revision and Publication of the
+Pharmacopoeia of the United States of America, Prof. F.W. Clarke,
+chief chemist of the United States Geological Survey, has furnished a
+table of atomic weights, revised upon the basis of the most recent
+data and his latest computations. The committee has resolved that this
+table be printed and furnished for publication to the professional
+press. The committee also requests that all calculations and
+analytical data which are to be given in reports or contributions
+intended for its use or cognizance be based upon the values in the
+table. It would be highly desirable that this table be adopted and
+uniformly followed by chemists in general, at least for practical
+purposes, until it is superseded by a revised edition. It would only
+be necessary for any author of a paper, etc., to state that his
+analytical figures are based upon "Prof. Clarke's table of atomic
+weights of December 6, 1890," or some subsequent issue.
+
+This table represents the latest and most trustworthy results, reduced
+to a uniform basis of comparison, with oxygen=16 as starting point of
+the system. No decimal places representing large uncertainties are
+used. When values vary, with equal probability on both sides, so far
+as our present knowledge goes, as in the case of cadmium (111.8 and
+112.2), the mean value is given in the table.
+
+The names of elements occurring in pharmaceutical, medicinal,
+chemicals, are printed in italics[1]:
+
+[Transcriber's Note 1: ITALICS represented by surrounding with "_".]
+
+
+  Name.           Symbol.  Atomic Weight.
+
+_Aluminum_.        _Al_        27.
+_Antimony_.        _Sb_       120.
+_Arsenic_.         _As_        75.
+_Barium_.          _Ba_       137.
+_Bismuth_.         _Bi_       208.9
+_Boron_.           _B_         11.
+_Bromine_.         _Br_        79.95
+Cadmium.            Cd        112.
+Caesium.            Cs        132.9
+_Calcium_.         _Ca_        40.
+_Carbon_.          _C_         12.
+_Cerium_.          _Ce_       140.2
+_Chlorine_.        _Cl_        35.45
+_Chromium_.       _Cr_         52.1
+Cobalt.             Co         59.
+Columbium.[1]       Cb         94.
+_Copper_.          _Cu_        63.4
+Didymium.[2]        Di        142.3
+Erbium.             Er        166.3
+Fluorine.           F          19.
+Gallium.            Ga         69.
+Germanium.          Ge         72.3
+Glucinum.[3]        Gl          9.
+_Gold_.            _Au_       197.3
+_Hydrogen_.        _H_          1.007
+Indium.             In        113.7
+_Iodine_.          _I_        126.85
+Iridium.            Ir        193.1
+_Iron_.            _Fe_        56.
+Lanthanum.          La        138.2
+_Lead_.            _Pb_       206.95
+_Lithium_.         _Li_         7.02
+_Magnesium_.       _Mg_        24.3
+_Manganese_.       _Mn_        55.
+_Mercury_.         _Hg_       200.
+_Molybdenum_.      _Mo_        96.
+Nickel.             Ni         58.7
+_Nitrogen_.        _N_         14.03
+Osmium.             Os        191.7
+_Oxygen_.[4]       _O_         16.
+Palladium.          Pd        106.6
+_Phosphorus_.      _P_         31.
+Platinum.           Pt        195.
+_Potassium_.       _K_         39.11
+Rhodium.            Rh        103.5
+Rubidium.           Rb         85.5
+Ruthenium.          Ru        101.6
+Samarium.           Sm        150.
+Scandium.           Sc         44.
+Selenium.           Se         79.
+_Silicon_.         _Si_        28.4
+_Silver_.          _Ag_       107.92
+_Sodium_.          _Na_        23.05
+Strontium.          Sr         87.6
+_Sulphur_.         _S_         32.06
+Tantalum.           Ta        182.6
+Tellurium.          Te        125.
+Terbium.            Tb        159.5
+Thallium.           Tl        204.18
+Thorium.            Th        232.6
+Tin.                Sn        119.
+Titanium.           Ti         48.
+Tungsten.           W         184.
+Uranium.            U         239.6
+Vanadium.           V          51.4
+Yterbium.           Yb        173.
+Yttrium.            Yt         89.1
+_Zinc_.            _Zn_        65.3
+Zirconium.          Zr         90.6
+
+--_Am. Jour. Pharm._
+
+[Footnote 1: Has priority over niobium.]
+
+[Footnote 2: Now split into neo-and praseo-didymium.]
+
+[Footnote 3: Has priority over beryllium.]
+
+[Footnote 4: Standard, or basis of the system.]
+
+       *       *       *       *       *
+
+
+
+
+THE TANNING MATERIALS OF EUROPE.
+
+
+The tanning materials of Europe are of an altogether different type
+from those of the United States. The population is so dense that the
+quantity of home materials produced is not nearly proportionate to the
+amount consumed, and consequently they must draw upon surrounding
+lands for their supply. The vegetation of these adjacent countries is
+of a much more tropical nature, and it naturally follows that the
+tanning materials are also of a different species.
+
+Tanning materials may be divided into two great classes, viz.:
+Physiological and pathological.
+
+
+PHYSIOLOGICAL.
+
+The first class includes those tannins which are the results of
+perfectly natural or normal growth, and a growth necessary to the
+development of vegetation, for instance, bark, sumac, etc., whereas
+the second class contains those which are the results of abnormal
+growth, caused by diseases, stings of insects, etc. An example of this
+is the gall. Both of these classes are used to a great extent in
+Europe, while only the first division is in general use in the United
+States. We will first consider the physiological tannins.
+
+
+_Oak Bark._--This material was, is, and will be for some time to come
+the main tanning material in use here in Europe. The advantages of the
+oak tannage are as fully appreciated here as in the United States. The
+European oak gives a light colored, firm leather, with good weight
+results, is comparatively cheap and of an excellent quality. The
+varieties are numerous, each country having its own kind. Those in
+most general use are:
+
+_Spiegel Rinde_ (mirror bark).--This bark is well distributed
+throughout Europe, and is peeled when the tree has attained a growth
+of from 12 to 24 years. It is marketed in three grades.
+
+_Reitel Rinde_--Is obtained from the same tree as the spiegel rinde,
+but after the tree has attained a growth of from 25 to 40 years.
+
+_Alte Pische_ (old oak).--Obtained from the aged tree. It is not as
+valuable as the younger bark, and consequently brings a much lower
+price.
+
+Spiegel rinde may be judged by small warts which appear on the shining
+surface of the bark. The presence of a great number of these, as a
+rule, indicates a high tannin percentage.
+
+Bosnia has fine oak trees, the bark containing 10 to 11 per cent.
+tannin.
+
+Bohemia has the _trauben eiche_ (grape oak).
+
+France uses the kirmess oak, which grows in the south of that country
+and in northern Africa. Two grades are made, viz., root and trunk.
+
+Tyrol has the evergreen oak--12 to 13 per cent. tannin.
+
+Sardinia possesses a cork oak, which yields 13 to 14 per cent.
+
+White oak is found throughout Europe, yielding 10 per cent. The price
+of oak bark varies a great deal. The assortment is much more strict
+than in the United States. In Austria it brings 4 to 5 fl., equal to
+$1.60 to $2 per kilo. (224 lb.); in Germany, 11 to 16 marks per 100
+kilos.[1]
+
+[Footnote 1: In the principal districts in America, removed from the
+cities, the price of oak bark is about $4 to $6 per cord or per ton
+of 2,240 lb. The hemlock bark, which gives a sole leather just as
+thoroughly tanned, but of a darker and reddish color, costs the
+larger tanners from $3 to $4 a cord.]
+
+The above mentioned varieties are all used for both upper and sole
+leather. In Germany a great deal of upper leather is pure oak tannage,
+but one seldom finds a pure oak tanned sole leather; it is almost
+always in combination with other tannics.
+
+
+_Pine Bark_--Is well distributed and is a very important tanning
+material. It bears the same relation to oak bark here as does hemlock
+in America, but its effects are quite different from hemlock. The best
+Austrian sorts are those of Styria and Bohemia, but that of Karuthen
+is also of good quality. The German pine comes from Thuringia to a
+great extent. The countries that consume the greatest amount of pine
+bark are Austria, Germany, Russia and Italy. The tannin contained
+varies from 5 to 16 per cent. Its use is almost wholly confined to the
+handlers, as its weight returns are not so satisfactory as oak or
+valonia. In case it should be used for layers it is always in
+combination with some better weight-giving tannic. For upper leather
+its use is limited.
+
+The bark is always peeled from the felled tree, and often the woodman
+accepts the bark in part payment for his labor; he then sells the bark
+to the tanner or agents who go about the country collecting bark. It
+is generally very nicely cleaned. I would here like to correct a
+mistake which tanners often make in their estimations of the value of
+barks. A tanner usually buys the bark of southern-grown trees in
+preference to that of trees grown in northern countries, as it is a
+common idea that southern vegetation contains more tannin than that of
+the north. This is a fallacy, as has not only been proved by careful
+analyses, but may also be found to be an incorrect conclusion after a
+moments' thought. Those trees which flourish in southern countries
+grow very rapidly, and as tannin is necessary to the development of
+leaf structure, etc., it is absorbed to a greater extent than is the
+case with the slower-growing tree of the north. The tannin contained
+in the sap does not increase in the same ratio as does the rapid
+growth, and it follows that the remainder in the bark is less than in
+the tree of slower growth.
+
+
+_Birch Bark_--Is at home in Russia, Norway, and Sweden. It is used for
+both upper and sole leather, but seldom alone. The bark is usually
+peeled from the full grown tree, and contains 4 to 9 per cent. tannin.
+
+
+_Willow Bark_--May also be found in the above mentioned countries and
+also in Germany. This material is used for both upper and sole
+leather, and contains 6 to 9 per cent. tannin. It is a very delicate
+material to use, as its tannin decomposes rapidly.
+
+
+_Erlen Rinde_--Is also a native of Germany, but is not used to any
+great extent. The same may be said of the larch, although this variety
+is also to be met with in Russia.
+
+
+_Mimosa Bark_--Is obtained from the acacia of Australia. It is a
+favorite in England. The varieties are as follows: Gold wattle, silver
+wattle (blackwood, lightwood), black wattle, green wattle. The gold
+wattle is a native of Victoria. Its cultivation was tried as an
+experiment in Algeria and met with some success. The trees are always
+grown from seeds. These seeds are laid in warm water for a few hours
+before sowing. The acacia may be peeled at eight years' growth and
+carries seeds. The Tasmania bark is very good; that from Adelaide
+likewise good.
+
+Sydney does not produce so good an article, but Queensland better. The
+bark is marketed in the stick, ground or chopped.
+
+Madagascar and the Reunion Islands have also a mimosa bark.
+
+The mimosa barks give a reddish colored leather, pump well and contain
+a high tannin percentage, 10 to 35 per cent.
+
+
+Now we will consider the fruit tanning materials.
+
+Valonia may truly be called one of the most generally used tanning
+agents at present employed in Europe. All countries consume it more or
+less. Valonia was first used in England about the beginning of this
+century. A few years later Germany began using it, and still later
+Austria introduced it. It is the fruit of the oak tree and is
+obtainable in Asia Minor and the adjacent islands. In form it
+resembles the American acorn, but in size it nearly trebles it. The
+fruit may be divided into two parts, namely, the cup and acorn, and
+the cup again divided into trillor and inner cup. The acorn only
+contains 10 per cent. tannin, whereas the cup contains from 25 to 40
+per cent.
+
+The percentage depends altogether upon the time of harvesting and the
+place of growth. The best valonia is derived from Smyrna, and is
+naturally the highest priced article. Valonia is worth from 22 to 28
+florins ($9 to $11) per 100 kilos. (224 pounds) at present. The other
+provinces and islands from which it is obtainable are Demergick,
+Govalia, Idem, Ivalzick, Troy (this is the best); Metelino Island, the
+vicinity of Smyrna. The material sold in three grades--prime, mazzano;
+seconds, una aqua; thirds, skart.
+
+The product of Smyrna generally averages:
+
+                       Tons.           Price.
+    Prime.        2,000 to  3,000      28 florins.
+    Seconds.      5,000 to 10,000      25    "
+    Thirds.      20,000 to 30,000      22    "
+
+The _Metilino_ valonia is a product of a neighboring island, and is a
+very good article. It may be easily distinguished by its thin cup. It
+is harvested in September.
+
+The _Candia_ valonia is nearly as long as it is wide, in contrast to
+the Smyrna, which is much wider than long. The recent harvest showed a
+return of 800 to 1,000 tons, but no assortment is made. A grade called
+the Erstlige is sold, this being the first which has fallen to the
+ground before maturing.
+
+A peculiarity of the valonia is that it often strikes out a sort of
+sugar sweat, which gives the cup a less attractive appearance, but
+denotes the presence of large quantities of tannin.
+
+Valonia is used almost wholly for sole leather, either alone or in
+combination with pine or oak bark or knoppern and myrabolams. The
+union of valonia and knoppern is that in most general use. Valonia
+gives the leather a yellowish appearance, as it deposits a great deal
+of yellow bloom. The leather is very firm and of good wearing
+qualities. The weight results are also excellent, as will be seen
+below. To sole leather there are usually given from one to three
+layers of valonia. The demand for valonia is increasing more and more
+every year, and the present outlook does not indicate any relaxation
+of its popularity. Its use for upper leather is very limited.
+
+Myrabolams are mainly used in England and Austria, and give a nice
+light-colored leather, both upper and sole, although rarely used
+alone. Their main use is for dyeing purposes. They are indigenous to
+the East Indies.
+
+Sumac is so well known that treating of it is superfluous. Its use is
+very extensive, and it is a general favorite for light, fine leather,
+which is mostly used for colors.
+
+_Gambier_--Is in general use in England and to some extent in Germany.
+
+_Catechu_.--Obtained from India, resembles gambier greatly. Its use is
+almost wholly confined to England. It is also consumed by the silk
+manufacturers in preference to gambier, for weighting purposes.
+
+
+PATHOLOGICAL.
+
+We now leave the physiological class and take up those tanning
+materials included in the pathological class, or those of abnormal
+growth.
+
+
+_Galls_.--These are not consumed to any great extent at the present
+period, but formerly they were used quite extensively. The galls are
+found upon the leaves of the oak or sumac, etc. The direct cause of
+their growth is that a certain wasp (cynips galles) stings into the
+leaf and after depositing its egg, flies away. The egg develops into a
+larva and then into a full-fledged wasp, boring its way out of the
+gall which has served as a protection and nourisher. This accounts for
+the hole noticed in almost every gall. The different varieties include
+Aleppo. It is found upon the same trees as the valonia and contains 60
+to 75 per cent. tannin; Istrian galls, 32 per cent. tannin; Persian,
+28 to 29 per cent. tannin. Chinese galls, giving 80 to 82 per cent.
+tannin, are the results of the sting of a louse, and make a very
+light-colored leather. The dyers also use this material for coloring.
+
+
+_Knoppern_--Belongs to the family of galls, and is a most important
+factor of commerce in Austria. The knopper is generally found on the
+acorn or leaf of the oak tree. The greatest quantity is derived from
+the steel oak of Hungary. The tannin contained varies from 27 to 33
+per cent. Knoppern are not being used so much now as formerly, and
+consequently the amount harvested lessens from year to year. Its main
+use was and is in combination with valonia as layers for sole leather.
+Valonia gives better weight results than knoppern, and is replacing
+knoppern more and more every year. The combination of knoppern,
+valonia and myrabolams is also quite popular, and gives good results.
+Knoppern are seldom used alone, being generally combined with some
+other tannin. Austria is almost the only consumer at present, but
+Germany used it extensively formerly.
+
+
+_Bark and Wood Extracts_--Are becoming general favorites throughout
+Europe, partly because of their weight-giving qualities and partly as
+the transportation costs so little; they can be used to strengthen
+weak bark liquors.
+
+_Oak Extracts_--Are well liked, both wood and bark, and are used
+extensively. Slavonia furnishes a great deal of it.
+
+_Chestnut Oak Wood Extract_--Is manufactured in quantities, and easily
+finds purchasers.
+
+_Pine Bark Extract_--Is also consumed in goodly amounts.
+
+_Quebracho Wood Extract_.--The wood is shipped from Brazil to Hamburg
+and other ports, and the tannin extracted there. Hamburg furnishes
+quantities of it.
+
+_Hemlock Extract_--Is used in Russia, and seems to have taken a hold
+on the shoe buyers' fancies, as they now make imitations of it in
+color. The hemlock that is consumed is imported from America.
+
+
+As most leather is sold by weight in Europe, the leather manufacturers
+aim to obtain as good weight results as possible, and often, I am
+sorry to say, do so at the sacrifice of quality. This is common to
+both upper and sole leather. Sole leather is nine times out of ten
+given false weight by forcing entirely foreign substances into the
+leather, such as glucose, barium chloride, magnesium chloride, resins,
+etc. Glucose and resin are also used for weighting upper leather.
+Leather is also weighted with extracts by overtanning. Leather buyers
+have become very wary of late and do not purchase large quantities
+before an analysis is made of a fair sample.
+
+One more word before I close. The governments and private individuals
+in Europe cultivate and raise trees for both lumber and bark purposes.
+The forests are excellently cared for by efficient foresters, and the
+result is that the tanners obtain much cleaner and better bark, and of
+a very even quality. Would it not be a good idea if some individual,
+who would certainly earn the everlasting gratefulness of the tanners,
+would look into this matter, and see that not only the lumber side of
+our forest cultivation is not neglected, but that the bark also is
+preserved and cared for? Of course, we can obtain all the bark
+necessary at present and for some time to come, but the time will come
+when we shall certainly regret not having taken these steps, if the
+lumbermen and bark peelers go on devastating magnificent forests.
+Below will be found a table of weight results. Sole leather tanned
+with these materials gives for every 100 lb. green hide the following
+quantities of finished leather:
+
+                                     lb.
+  Oak bark                          48 to 54
+  "   extract                       55 to 56
+  Pine bark                         44 to 46
+  "   extract                       48 to 50
+  Willow                            45 to 46
+  Birch bark and oak extract        49 to 51
+  Quebracho wood and extract        48 to 49
+  Valonia                           52 to 56
+  Knoppern                          51 to 53
+  Myrabolams                        50
+  Knoppern, myrabolams and valonia  52 to 53
+  Hemlock                           55
+
+Specification of tanning materials used in different countries:
+
+_France_.
+Oak bark (kirmess).
+Sumac.
+Chestnut wood extract.
+Quebracho "     "
+Some gambier.
+
+_Italy_.
+Oak bark.
+Pine "
+Sumac.
+Valonia.
+
+_England_.
+Oak bark.
+Divi divi.
+Myrabolams.
+Valonia.
+Mimosa.
+Extracts { Oak bark and wood hemlock.
+Gambier.
+Cutch.
+
+_Germany and Austria_.
+Oak bark.
+Pine "
+Willow bark.
+Valonia.
+Knoppern.
+Myrabolams.
+         { Oak bark and wood.
+Extracts { Pine bark and wood.
+
+_Russia._
+Birch bark.
+Willow "
+Oak    "
+Pine   "
+Hemlock extract.
+
+
+_Norway and Sweden_.
+Birch bark.
+Willow "
+Oak    "
+
+                                      WALTER J. SALOMON.
+--_Shoe and Leather Reporter_.
+
+       *       *       *       *       *
+
+
+
+
+AN APPARATUS FOR HEATING SUBSTANCES IN GLASS TUBES UNDER PRESSURE.[1]
+
+[Footnote 1: Read at the meeting of the Chemical Section of the
+Franklin Institute held March 17, 1891.]
+
+By H. PEMBERTON, Jr.
+
+
+Chemists who do not happen to have in their laboratories oil or air
+baths for heating closed tubes can make an air bath at short notice
+from materials furnished by all dealers in steam fittings.
+
+_Order_:
+
+(1) One four-inch wrought iron pipe, eighteen inches out to out, with
+usual thread on each end. At about nine inches from either end this
+pipe is drilled and tapped for a one-inch nipple, in such a manner
+that a pipe introduced would pass, not on a line with the radius, but
+about half way between the axis of the four-inch pipe and its walls;
+in other words, it would be on a line with a chord of the circle.
+
+(2) One one-inch wrought iron nipple, two inches long, one-inch thread
+on one end.
+
+(3) Two four-inch malleable iron caps, drilled and tapped for a
+one-inch pipe.
+
+(4) One one-inch wrought iron pipe, twenty-four inches out to out,
+with a three-inch straight thread on each end.
+
+(5) Two one-inch iron caps. A hole, one-eighth of an inch in diameter,
+is drilled in the end of one of these caps.
+
+The above order can be given _literatim_, and will be understood by
+the dealer, who will furnish, at a trifling cost, the materials, cut
+and tapped as ordered.
+
+Fig. 1 shows how the whole is put together. The numbers on the figure
+correspond also to the numbers of the paragraphs of the order as given
+above.
+
+[Illustration: FIG. 1.]
+
+[Illustration: FIG. 2.]
+
+Fig. 2 is an end section. A cork is inserted in 2 and through it a
+thermometer, the bulb of which is on a level with the interior pipe.
+The whole is supported on a few bricks at either end, and is kept
+steady and in place by a couple of weights or half bricks. It is
+heated by one or two Bunsen burners, according to the temperature
+desired.--_Jour. Fr. Institute_.
+
+       *       *       *       *       *
+
+
+
+
+TESTING CEMENT.
+
+
+An improved method of testing Portland cement has been adopted by M.
+Deval, Chief Superintendent of Bridges and Roads, who has charge,
+under M. Saele, of the Public Works Laboratory of the City of Paris.
+The principal difference in M. Deval's method consists in the use of
+hot water for the period of hardening. The briquettes are made in the
+usual way, and of the ordinary size; and the cement to be tested is
+gauged with three times its weight of normal sand, and the smallest
+quantity of water possible. After preparation, the briquettes are
+allowed to harden in air for a period ranging from 24 hours for
+Portland cement to 30 days for certain slow-setting hydraulic limes.
+After this period, the samples are immersed in water kept at a
+temperature of 80° C., in which they remain for from two to seven
+days. The briquettes are then broken in the ordinary way. After
+careful comparisons of many varieties of cement hardened hot and cold,
+M. Deval finds that cold tests are fallacious, inasmuch as they may
+fail to detect bad material. Portland cement of good quality will not
+only stand water at 80° C., but will attain in seven days about the
+same strength as is reached in the cold after 28 days. The hot test
+therefore saves time. The hot test is an unfailing proof for free
+lime; cements containing this constituent betraying weakness, and
+cracking, swelling, and disintegrating in a very significant manner.
+This last result is regarded as a valuable quality of the new method
+of testing cement, the general effect of which appears to be to
+enhance the test value of really good cements, while depreciating
+those of an inferior character.
+
+       *       *       *       *       *
+
+
+THE SCIENTIFIC AMERICAN Architects and Builders Edition
+
+$2.50 a Year. Single Copies, 25 cts.
+
+
+This is a Special Edition of the SCIENTIFIC AMERICAN, issued
+monthly--on the first day of the month. Each number contains about
+forty large quarto pages, equal to about two hundred ordinary book
+pages, forming, practically, a large and splendid Magazine of
+Architecture, richly adorned with _elegant plates in colors_ and with
+fine engravings, illustrating the most interesting examples of modern
+Architectural Construction and allied subjects.
+
+A special feature is the presentation in each number of a variety of
+the latest and best plans for private residences, city and country,
+including those of very moderate cost as well as the more expensive.
+Drawings in perspective and in color are given, together with full
+Plans, Specifications, Costs, Bills of Estimate, and Sheets of
+Details.
+
+No other building paper contains so many plans, details, and
+specifications regularly presented as the SCIENTIFIC AMERICAN.
+Hundreds of dwellings have already been erected on the various plans
+we have issued during the past year, and many others are in process of
+construction.
+
+Architects, Builders, and Owners will find this work valuable in
+furnishing fresh and useful suggestions. All who contemplate building
+or improving homes, or erecting structures of any kind, have before
+them in this work an almost _endless series of the latest and best
+examples_ from which to make selections, thus saving time and money.
+
+Many other subjects, including Sewerage, Piping, Lighting, Warming,
+Ventilating, Decorating, Laying out of Grounds, etc., are illustrated.
+An extensive Compendium of Manufacturers' Announcements is also given,
+in which the most reliable and approved Building Materials, Goods,
+Machines, Tools, and Appliances are described and illustrated, with
+addresses of the makers, etc.
+
+The fullness, richness, cheapness, and convenience of this work have
+won for it the Largest Circulation of any Architectural publication
+in the world.
+
+A Catalogue of valuable books on Architecture, Building, Carpentry,
+Masonry, Heating, Warming, Lighting, Ventilation, and all branches of
+industry pertaining to the art of Building, is supplied free of
+charge, sent to any address.
+
+MUNN & CO., Publishers, 361 Broadway, New York.
+
+       *       *       *       *       *
+
+
+BUILDING PLANS AND SPECIFICATIONS.
+
+
+In connection with the publication of the BUILDING EDITION of the
+SCIENTIFIC AMERICAN, Messrs. Munn & Co. furnish plans and
+specifications for buildings of every kind, including Churches,
+Schools, Stores, Dwellings, Carriage Houses, Barns, etc.
+
+In this work they are assisted by able and experienced architects.
+Full plans, details, and specifications for the various buildings
+illustrated in this paper can be supplied.
+
+Those who contemplate building, or who wish to alter, improve, extend,
+or add to existing buildings, whether wings, porches, bay windows, or
+attic rooms, are invited to communicate with the undersigned. Our work
+extends to all parts of the country. Estimates, plans, and drawings
+promptly prepared. Terms moderate. Address
+
+MUNN & CO., 361 BROADWAY, NEW YORK.
+
+       *       *       *       *       *
+
+THE
+SCIENTIFIC AMERICAN SUPPLEMENT.
+
+PUBLISHED WEEKLY.
+
+Terms of Subscription, $5 a year.
+
+Sent by mail, postage prepaid, to subscribers in any part of the
+United States or Canada. Six dollars a year, sent, prepaid, to any
+foreign country.
+
+All the back numbers of THE SUPPLEMENT, from the commencement, January
+1, 1876, can be had. Price, 10 cents each.
+
+All the back volumes of THE SUPPLEMENT can likewise be supplied. Two
+volumes are issued yearly. Price of each volume, $2.50 stitched in
+paper, or $3.50 bound in stiff covers.
+
+COMBINED RATES.--One copy of SCIENTIFIC AMERICAN and one copy of
+SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.
+
+A liberal discount to booksellers, news agents, and canvassers.
+
+MUNN & CO., Publishers, 361 Broadway, New York, N.Y.
+
+       *       *       *       *       *
+
+
+A NEW CATALOGUE OF VALUABLE PAPERS
+
+Contained in SCIENTIFIC AMERICAN SUPPLEMENT during the past ten years,
+sent _free of charge_ to any address. MUNN & CO., 361 Broadway, New
+York.
+
+       *       *       *       *       *
+
+
+USEFUL ENGINEERING BOOKS
+
+Manufacturers, Agriculturists, Chemists, Engineers, Mechanics,
+Builders, men of leisure, and professional men, of all classes, need
+good books in the line of their respective callings. Our post office
+department permits the transmission of books through the mails at very
+small cost. A comprehensive catalogue of useful books by different
+authors, on more than fifty different subjects, has recently been
+published, for free circulation, at the office of this paper. Subjects
+classified with names of author. Persons desiring a copy have only to
+ask for it, and it will be mailed to them. Address,
+
+    MUNN & CO., 361 Broadway, New York.
+
+       *       *       *       *       *
+
+
+PATENTS!
+
+MESSRS. MUNN & CO., in connection with the publication of the
+SCIENTIFIC AMERICAN, continue to examine improvements, and to act as
+Solicitors of Patents for Inventors.
+
+In this line of business they have had _forty-five years' experience_,
+and now have _unequaled facilities_ for the preparation of Patent
+Drawings, Specifications, and the prosecution of Applications for
+Patents in the United States, Canada, and Foreign Countries. Messrs.
+Munn & Co. also attend to the preparation of Caveats, Copyrights for
+Books, Labels, Reissues, Assignments, and Reports on Infringements of
+Patents. All business intrusted to them is done with special care and
+promptness, on very reasonable terms.
+
+A pamphlet sent free of charge, on application, containing full
+information about Patents and how to procure them; directions
+concerning Labels, Copyrights, Designs, Patents, Appeals, Reissues,
+Infringements, Assignments, Rejected Cases. Hints on the Sale of
+Patents, etc.
+
+We also send, _free of charge_, a Synopsis of Foreign Patent Laws,
+showing the cost and method of securing patents in all the principal
+countries of the world.
+
+  MUNN & CO., Solicitors of Patents,
+  361 Broadway, New York.
+
+BRANCH OFFICES.--No. 622 and 624 F Street, Pacific Building, near 7th
+Street, Washington, D.C.
+
+
+
+
+
+
+
+
+
+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+803, May 23, 1891, by Various
+
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+<title>The Project Gutenberg eBook of Scientific American
+Supplement, May 23, 1891</title>
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+
+The Project Gutenberg EBook of Scientific American Supplement, No. 803,
+May 23, 1891, 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: Scientific American Supplement, No. 803, May 23, 1891
+
+Author: Various
+
+Release Date: September 3, 2004 [EBook #13358]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Victoria Woosley and the
+Online Distributed Proofreading Team.
+
+
+
+
+
+
+</pre>
+
+<p class="ctr"><a href="./images/title.png"><img src="images/title-th.jpg" alt=""></a></p>
+<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 803</h1>
+<h2>NEW YORK, May 23, 1891</h2>
+<h4>Scientific American Supplement. Vol. XXXI., No. 803.</h4>
+<h4>Scientific American established 1845</h4>
+<h4>Scientific American Supplement, $5 a year.</h4>
+<h4>Scientific American and Supplement, $7 a year.</h4>
+<hr />
+<table summary="Contents" border="0" cellspacing="5">
+<tr>
+<th colspan="2">TABLE OF CONTENTS.</th>
+</tr>
+<tr>
+<td valign="top">I.</td>
+<td><a href="#ast-1">
+ASTRONOMY.&mdash;The Great Equatorial of the Paris Observatory.&mdash;
+      The new telescope recently put in use in Paris.&mdash;Description of
+      the instrument and of its effects.&mdash;3 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">II.</td>
+<td><a href="#chem-1">
+CHEMISTRY.&mdash;An Apparatus for Heating Substances in Glass
+      Tubes under Pressure.&mdash;By H. PEMBERTON, Jr.&mdash;A simple apparatus
+      for effecting this purpose, avoiding risk of personal injury.&mdash;
+      2 illustrations</a></td>
+</tr>
+<tr>
+<td></td>
+<td><a href="#chem-2">
+ Table of Atomic Weights.&mdash;A revised table of atomic weights,
+      giving the results of the last determinations, and designed for
+      every-day use</a></td>
+</tr>
+<tr>
+<td></td>
+<td><a href="#chem-3">
+Testing Cement.&mdash;A laboratory process for testing Portland cement</a></td>
+</tr>
+<tr>
+<td valign="top">III.</td>
+<td><a href="#ce-1">
+CIVIL ENGINEERING.&mdash;The Compressed Air System of Paris.
+      &mdash;An elaborate review of this great installation for the transmission
+      of power.&mdash;The new compressed air station, with full details
+      of performances of apparatus, etc.&mdash;10 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">IV.</td>
+<td><a href="#ent-1">
+ENTOMOLOGY.&mdash;Report on Insects.&mdash;Continuation of this report
+      on noxious insects.&mdash;Their habits and how to cope with them.
+      &mdash;18 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">V.</td>
+<td><a href="#flo-1">
+FLORICULTURE.&mdash;Lily of the Valley.&mdash;Practical notes on the
+      cultivation of this popular flower.&mdash;How to raise it and force the
+      growth
+</a></td>
+</tr>
+<tr>
+<td valign="top">VI.</td>
+<td><a href="#math-1">
+MATHEMATICS.&mdash;The Conic Sections.&mdash;By Prof. C.W.
+      MACCORD.&mdash;Examination of the four conic sections with a general
+      definition applicable to all.&mdash;6 illustrations </a></td>
+</tr>
+<tr>
+<td valign="top">VII.</td>
+<td><a href="#me-1">
+MECHANICAL ENGINEERING.&mdash;The Builders of the Steam
+      Engine&mdash;The Founders of Modern Industries and Nations.&mdash;By Dr.
+      R.H. THURSTON.&mdash;Prof. Thurston's address before the Centennial
+      Celebration of the American Patent System at Washington,
+      D.C.&mdash;The early history of the steam engine and its present position
+      in the world
+</a></td>
+</tr>
+<tr>
+<td valign="top">VIII.</td>
+<td><a href="#misc-1">
+MISCELLANEOUS.&mdash;The Breeds of Dogs.&mdash;Popular description
+      of the different breeds of dogs most affected by amateurs.&mdash;6.
+      illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">IX.</td>
+<td><a href="#nav-1">
+NAVAL ENGINEERING.&mdash;Modern Armor.&mdash;By F.R. BRAINARD.&mdash;The
+      development of modern ship armor, from laminated
+      sandwiched and compound types to the present solid armor.&mdash;9 illustrations</a></td>
+</tr>
+<tr>
+<td valign="top">X.</td>
+<td><a href="#pisc-1">
+PISCICULTURE.&mdash;Restocking the Seine with Fish.&mdash;The introduction
+      of 40,000 fry of California trout and salmon, designed to restock
+      the Seine, depopulated of fish by explosions of dynamite
+      used in breaking up the ice.&mdash;1 illustration</a></td>
+</tr>
+<tr>
+<td valign="top">XI.</td>
+<td><a href="#rr-1">
+RAILWAY ENGINEERING.&mdash;Improved Hand Car.&mdash;A novelty
+      in the construction of hand cars, avoiding the production of a
+      dead center.&mdash;1 illustration</a></td>
+</tr>
+<tr>
+<td valign="top">XII.</td>
+<td><a href="#tec-1">
+TECHNOLOGY.&mdash;The Tanning Materials of Europe.&mdash;The natural
+      tanning materials and pathological or abnormal growth tanning
+      materials described and classified, with relative power</a></td>
+</tr>
+</table>
+<hr />
+
+<a name="ast-1"></a><h2>THE GREAT EQUATORIAL OF THE
+PARIS OBSERVATORY.</h2>
+
+<p>The great instrument which has just completed
+the installation of our national observatory
+is constructed upon the same principle as
+the elbowed equatorial, 11 in. in diameter, established
+in 1882, according to the ingenious
+arrangement devised as long ago as 1872, by
+Mr. Loewy, assistant director of the Paris Observatory.</p>
+
+
+<p>We shall here recall the fact that the elbowed
+equatorial consists of two parts joined at right
+angles. One of these is directed according to
+the axis of the world, and is capable of revolving
+around its own axis, and the other, which
+is at right angles to it, is capable of describing
+around the first a plane representing the celestial
+equator. At the apex of the right angle
+there is a plane mirror of silvered glass inclined
+at an angle of 45 deg. with respect to the
+optical axis, and which sends toward the ocular
+the image coming from the objective and already
+reflected by another and similar plane
+mirror. The objective and this second mirror
+(which is inclined at an angle of 45 deg.) are
+placed at the extremity of the external part of
+the tube, and form part of a cube, movable
+around the axis of the instrument at right
+angles with the axis of the world. The diagram
+in Fig. 3 will allow the course of a luminous
+ray coming from space to be easily
+understood. The image of the star, A, toward
+which the instrument is directed, traverses the
+objective, B C, is reflected first from the mirror, B D,
+and next from the central mirror, E F, and finally
+reaches O, at the ocular where the observer is stationed.</p>
+
+<p class="ctr">
+<img src="images/1-fig3.png" alt="FIG. 3. COURSE OF LUMNIOUS RAY" title="">
+<br clear="all" />FIG 3.&mdash;DIAGRAM SHOWING THE COURSE OF
+A LUMINOUS RAY IN THE GREAT EQUATORIAL.</p>
+
+<p>This new equatorial differs from the first model by
+its much larger dimensions and its extremely remarkable
+mechanical improvements. The optical part,
+which is admirably elaborated, consists of a large astronomical
+objective 24 in. in diameter, and of a photographic
+objective of the same aperture, capable of
+being substituted, one for the other, according to the
+nature of the work that it is desired to accomplish by
+the aid of this colossal telescope, the total length of
+which is 59 ft. The two plane mirrors which complete
+the optical system have, respectively, diameters of 34
+in. and 29 in. These two magnificent objectives and
+the two mirrors were constructed by the Brothers
+Henry, whose double reputation as astronomers and
+opticians is so universally established. The mechanical
+part is the successful work of Mr. Gautier, who has
+looked after every detail with the greatest care, and
+has thus realized a true <i>chef d'oeuvre</i>. The colossal instrument,
+the total weight of which is 26,400 lb., is
+maneuvered by hand with the greatest ease. A clockwork
+movement, due to the same able manufacturer, is
+capable, besides, of moving the instrument with all the
+precision desirable, and of permitting it to follow the
+stars in their travel across the heavens. A star appearing
+in the horizon can thus be observed from its
+rising to its setting. The astronomer, his eye at the
+ocular, is always conveniently seated at the same place,
+observing the distant worlds, rendered immovable, so
+to speak, in the field of the instrument. For stars
+which, like the moon and the planets, have a course
+different from the diurnal motion, it is possible to
+modify the running of the clockwork, so that they can
+thus be as easily followed as in the preceding case.
+Fig. 1 gives a general view of the new installation, for
+which it became necessary
+to build a special edifice 65
+ft. in height on the ground
+south of the observatory
+bordering on the Arago
+Boulevard. A large movable
+structure serves for
+covering the external part
+of the instrument. This
+structure rests on rails,
+upon which it slides toward
+the south when it is
+desired to make observations.
+It will be seen from
+the figure how the principal
+axis of the instrument
+rests upon the two masonry
+pillars, one of which is
+49 ft. and the other 13 ft.
+in height.</p>
+
+<p class="ctr"><a href="./images/1-fig1.png">
+<img src="images/1-fig1-th.jpg" alt="FIG 1." title="">
+</a><br clear="all" /> FIG 1.&mdash;THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.</p>
+
+<p> The total cost of the
+pavilion, rolling structure,
+and instrument (including
+the two objectives) will
+amount to about $80,000
+after the new equatorial
+has been provided with the
+scientific apparatus that
+necessarily have to accompany
+it for the various
+and numerous applications
+to which the use of
+it will give rise.</p>
+
+<p class="ctr"><a href="./images/1-fig2.png">
+<img src="images/1-fig2-th.jpg" alt="FIG 2.--OCULAR OF THE GREAT EQUATORIAL." title=""></a>
+<br clear="right" /> FIG 2.&mdash;OCULAR OF THE GREAT EQUATORIAL.</p>
+
+<p>Fig. 2 shows us the room
+in the observatory in
+which the astronomer,
+seated in his chair, is completely
+protected against
+the inclemencies of the
+weather. Here, with his eye applied to the ocular, he
+can, without changing position (owing to all the
+handles that act at his will upon the many transmissions
+necessary for the maneuvering), direct his instrument
+unaided toward every point of the heavens with
+wonderful sureness and precision. The observer has
+before him on the same plane two divided circles, one
+of which gives the right ascensions and the other the
+declinations, and which he consults at each observation
+for the exact orientation of the equatorial.
+</p>
+
+<p>All the readings are done by the aid of electric lamps
+of very small dimensions, supplied by accumulators,
+and which are lighted at will. Each of these lamps is
+of one candle power; two of them are designed for the
+reading of the two circles of right ascension
+and of declination; a third serves for the reading
+of the position circle of the micrometer;
+two others are employed for the reading of the
+drums fixed upon the micrometric screws; four
+others serve for rendering the spider threads of
+the reticule brilliant upon a black ground; and
+still another serves for illuminating the field of
+the instrument where the same threads remain
+black upon a luminous ground. The currents
+that supply these lamps are brought over two
+different circuits, in which are interposed rheostats
+that permit of graduating the intensity
+of the light at will.</p>
+
+<p>Since the installation of the first model of an
+elbowed equatorial of 11 in. aperture, in 1882,
+at the Paris Observatory, the numerous and indisputable
+advantages of this sort of instrument
+have led a certain number of observatories
+to have similar, but larger, instruments
+constructed. In France, the observatories of
+Alger, Besancon, and Lyons have telescopes of
+this kind, the objectives of which have diameters
+of from 12 in. to 13 in., and which have
+been used for several years past in equatorial
+observations of all kinds. The Vienna Observatory
+has for the last two years been using an
+instrument of this kind whose objective has
+an aperture of 15 inches. Another equatorial
+of the same kind, of 16 in. aperture, is now in
+course of construction for the Nice Observatory,
+where it will be especially employed as a
+seeker of exceptional power&mdash;a role to which
+this kind of instrument lends itself admirably.
+The optical part of all these instruments was furnished
+by the Messrs. Henry, and the mechanical part by Mr.
+Gautier.</p>
+
+<p>The largest elbowed equatorial is, therefore, that of
+the Paris Observatory. Its optical power, moreover,
+corresponds perfectly to its huge dimensions. The experimental
+observations which have already been
+made with it fully justify the hopes that we had a
+right to found upon the professional skill of the eminent
+artists to whom we owe this colossal instrument.
+The images of the stars were given with the greatest
+sharpness, and it was possible to study the details of
+the surface of the moon and other planets, and several
+star clusters, in all their peculiarities, in the most remarkable
+manner.</p>
+
+<p>When it shall become possible to make use of this
+equatorial for celestial photography, there is no doubt
+that we shall obtain the most important results. As
+regards the moon, in particular, the photographing of
+which has already made so great progress, its direct
+image at the focus of the large 24 in. photographic objective
+will have a diameter of 11 in., and, being magnified,
+will be capable of giving images of more than
+3 ft. in diameter.&mdash;<i>La Nature</i>.</p>
+
+<hr />
+
+<a name="flo-1"></a><h2>LILY OF THE VALLEY.</h2>
+
+<p>There is no flower more truly and universally popular
+than the lily of the valley. What can be more delicious
+and refreshing than the scent of its fragrant
+flowers? What other plant can equal in spring the attractiveness
+of its pillars of pure white bells half hidden
+in their beautiful foliage? There are few gardens
+without a bed of lily of the valley, but too often the
+place chosen for it is some dark corner where nothing
+else would be expected to grow, but it is supposed as a
+matter of course that "it will do for a lily bed." The
+consequence is that although
+these lilies are very
+easy things to cultivate, as
+indeed they ought to be,
+seeing that they grow wild
+in the woods of this and
+other countries, yet one
+hears so often from those
+who take only a slight interest
+in practical gardening,
+"I have a lily bed,
+but I scarcely ever get any
+lilies." Wild lilies are hardly
+worth the trouble of gathering,
+they are so thin
+and poor; it is interesting
+to find a plant so beautiful
+and precious in the garden
+growing wild in the woods,
+but beyond that the flowers
+themselves are worth
+but very little. This at
+once tells us an evident
+fact about the lily of the
+valley, viz., that it does
+require cultivation. It is
+not a thing to be left alone
+in a dark and dreary corner
+to take care of itself
+anyhow year after year.
+People who treat it so deserve
+to be disappointed
+when in May they go to the
+lily bed and find plenty of
+leaves, but no flowers, or, if
+any, a few poor, weak attempts
+at producing blossoms,
+which ought to be
+so beautiful and fragrant.
+
+One great advantage of this lovely spring flower is that
+it can be so readily and easily forced. Gardeners in large
+places usually spend several pounds in the purchase of
+crowns and clumps of the lily of the valley, which
+they either import direct from foreign nurserymen or
+else procure from their own dealer in such things, who
+imports his lilies in large quantities from abroad. But
+we may well ask, Have foreign gardeners found out
+some great secret in the cultivation of this plant? Or is
+their climate more suitable for it? Or their soil adapted
+to growing it and getting it into splendid condition for
+forcing? It is impossible that the conditions for growing
+large and fine heads of this lily can be in any way
+better in Berlin or elsewhere than they are in our own
+land, unless greater heat in summer than we experience
+in England is necessary for ripening the growths
+in autumn.</p>
+
+<p>There is another question certainly as to varieties;
+one variety may be superior to another, but surely if
+so it is only on the principle of the survival of the fittest,
+that is to say, by carefully working on the finest
+forms only and propagating from them, a strong and
+vigorous stock may be the result, and this stock may
+be dignified with a special name. For my own part
+what I want is to have a great abundance of lily of the
+valley from February till the out-door season is over.
+To do this with imported clumps would, of course, be
+most costly, and far beyond what any person ought
+to spend on mere flowers. Though it must be remembered
+that it is an immense advantage to the parish
+priest to be able to take bright and sweet flowers to the
+bedside of the sick, or to gratify the weary spirit of a
+confirmed invalid, confined through all the lovely
+spring time to the narrow limits of a dull room, with
+the fragrant flowers of the lily of the valley. I determined,
+therefore, that I would have an abundance of
+early lilies, and that they should not be costly, but
+simply produced at about the same expense as any
+other flowers, and I have been very successful in accomplishing
+this by very simple means. First of all, it
+is necessary to have the means of forcing, that is to say
+the required heat, which in my case is obtained from
+an early vinery. I have seen lilies forced by pushing
+the clumps in under the material for making a hot bed
+for early cucumbers, the clumps being drawn out, of
+course, as soon as the flowers had made a good start.
+They have then to be carefully and very gradually exposed
+to full light, but often, although fine heads of
+bloom may be produced in this way, the leaves will be
+few and poor.</p>
+
+<p>My method is simply this: In the kitchen garden
+there is the old original bed of lilies of the valley in a
+corner certainly, but not a dark corner. This is the
+reservoir, as were, from whence the regular supply
+of heads for special cultivation is taken. This large
+bed is not neglected and left alone to take care of itself,
+but carefully manured with leaf mould and peat
+moss manure from the stable every year. Especially
+the vacant places made by taking out the heads for
+cultivation are thus filled up.</p>
+
+<p>Then under the east wall another piece of ground is
+laid out and divided into four plots. When I first began
+to prepare for forcing I waited four years, and
+had one plot planted with divided heads each year.
+Clumps are taken up from the reserve bed and then
+shaken out and the heads separated, each with its little
+bunch of fibrous roots. They are then carefully planted
+in one of the plots about 4 in. or 5 in. apart, the ground
+having previously been made as light and rich as possible
+with plenty of leaf mould. I think the best time
+for doing this is in autumn, after the leaves have
+turned yellow and have rotted away; but frequently
+the operation has been delayed till spring, without
+much difference in the result.</p>
+
+<p>Asparagus is usually transplanted in spring, and
+there is a wonderful affinity between the two plants,
+which, of course, belong to the same order. It was a
+long time to wait&mdash;four years&mdash;but I felt there was no
+use in being in too great a hurry, and every year the
+plants manifestly improved, and the buds swelled up
+nicely and looked more plump each winter when the
+leaves were gone. It must be remembered also that a
+nice crop of flowers could be gathered each year.
+When the fourth year came, the first plot was divided
+up into squares about 2 ft. each way, and taken up before
+any hard frost or snow had made their appearance,
+and put away on the floor of an unused stable.
+From the stable they are removed as required in the
+squares to the vinery, where they grow beautifully,
+not sending up merely fine heads of bloom without a
+vestige of leaf, but growing as they would in spring out
+of doors with a mass of foliage, among which one has
+to search for the spikes of flower, so precious for all
+sorts of purposes at that early season of the year.</p>
+
+<p>The spikes produced in this way do not equal in
+thickness and substance of petal the flowers which
+come from more carefully prepared clumps imported
+from Berlin, but they are fine and strong, and above
+all most abundant. I can not only supply the house
+and small vases for the church, but also send away
+boxes of the flowers to friends at a distance, besides the
+many gifts which can be made to those who are ill or
+invalids. Few gifts at such a time are more acceptable
+than a fragrant nosegay of lily of the valley. In order
+to keep the supply of prepared roots ready year after
+year, a plot of ground has only to be planted each
+autumn, so that in the rotation of years it may be
+ready for forcing when its turn shall come.</p>
+
+<p>As the season advances, as every one knows who has
+attempted to force the lily of the valley, much less
+time is taken in bringing the flowers to perfection under
+precisely the same circumstances as those in which
+the first sods are forced. In February or earlier the
+buds are more unwilling to start; there seems to be
+a natural repugnance against being so soon forced
+out of the winter's sleep and rest. But when the flowers
+do come, they are nearly as fine and their leaves are
+quite as abundant in this way of forcing as from the
+pieces introduced much later into heat. It would
+be easy to preserve the squares after all the flowers are
+gathered, but I found that they would not, like strawberries,
+kindly furnish forth another crop later on in
+the year, and, therefore, mine are flung away; and I
+have often pitied the tender leaves in the frost and
+snow after their short sojourn in the hot climate of the
+vinery. But the reserve bed will always supply an
+ample quantity of fresh heads, and it is best to take
+the new plants for preparation in the kitchen garden
+from this reserve bed.</p>
+
+<p>This very simple method of forcing lilies of the
+
+valley is within the reach of any one who has even a
+small garden and a warm house, and these two things
+are becoming more and more common among us
+every day.&mdash;<i>A Gloucestershire Parson, in The Garden</i>.</p>
+
+<hr />
+
+[Continued from SUPPLEMENT, No. 802, page 12820.]
+
+<a name="ent-1"></a><h2>REPORT ON INSECTS</h2>.
+
+<h3>THE ONION MAGGOT.</h3>
+
+<h4><i>Phorbia ceparum</i> (Meig.)</h4>
+
+
+<p>
+Early in June a somewhat hairy fly, Fig. 9, may be
+seen flying about, and depositing its eggs on the leaves
+of the young onion plants, near the roots, Fig. 10.</p>
+
+
+<img src="images/2-fig9.png" align="left" alt="FIG. 9." title="">
+
+<img src="images/2-fig10.png" align="right" alt="FIG. 10." title="">
+<br clear="all" />
+
+<p>Dr. Fitch describes this fly as follows: "It has a considerable
+resemblance to the common house fly, though
+when the two are placed side by side, this is observed
+as being more slender in its form. The two sexes are
+readily distinguished from each other by the eyes,
+which in the males are close together, and so large as
+to occupy almost the whole surface of the head, while
+in the females they are widely separated from each
+other. These flies are of an ash gray color, with the
+head silvery, and a rusty black stripe between the eyes,
+forked at its hind end. And this species is particularly
+distinguished by having a row of black spots along
+the middle of the abdomen or hind body, which sometimes
+run into each other, and then forming a continuous
+stripe.</p>
+
+<p>"This row of spots is quite distinct in the male, but
+in the female is very faint, or is often wholly imperceptible.
+This fly measured 0.22 to 0.25 inch in length,
+the females being usually rather larger than the males."
+The eggs are white, smooth, somewhat oval in outline,
+and about one twenty-fifth of an inch in length. Usually
+not more than half a dozen are laid on a single
+plant, and the young maggot burrows downward within
+the sheath, leaving a streak of pale green to indicate
+its path, and making its way into the root, devours all
+except the outer skin.</p>
+
+<p>The maggots reach their full growth in about two
+weeks, when they are about one-third of an inch long,
+white and glossy, tapering from the posterior end to
+the head, which is armed with a pair of black, hook-like
+jaws. The opposite end is cut off obliquely and has
+eight tooth-like projections around the edge, and a
+pair of small brown tubercles near the middle. Fig.
+11 shows the eggs, larva, and pupa, natural size and
+enlarged.</p>
+
+<img src="images/2-fig11.png" align="right" alt="FIG. 11." title="">
+
+<p>They usually leave the onions and transform to pupæ
+within the ground. The form of the pupa does not
+differ very much from the maggot, but the skin has
+hardened and changed to a chestnut brown color, and
+they remain in this stage about two weeks in the summer,
+when the perfect flies emerge. There are successive
+broods during the season, and the winter is passed
+in the pupa stage.</p>
+
+<p>The following remedies have been suggested:</p>
+
+<p>Scattering dry, unleached wood ashes over the plants
+as soon as they are up, while they are wet with dew,
+and continuing this as often as once a week through
+the month of June, is said to prevent the deposit of
+eggs on the plants.</p>
+
+<p>Planting the onions in a new place as remote as possible
+from where they were grown the previous year
+has been found useful, as the flies are not supposed to
+migrate very far.</p>
+
+<p>Pulverized gas lime scattered along between the rows
+has been useful in keeping the flies away.</p>
+
+<p>Watering with liquid from pig pens collected in a
+tank provided for the purpose, was found by Miss Ormerod
+to be a better preventive than the gas lime.</p>
+
+<p>When the onions have been attacked and show it by
+wilting and changing color, they should either be taken
+up with a trowel and burned, or else a little diluted
+carbolic acid, or kerosene oil, should be dropped on
+the infested plants to run down them and destroy the
+maggots in the roots and in the soil around them.</p>
+
+<p>Instead of sowing onion seed in rows, they should
+be grown in hills, so that the maggots, which are footless,
+cannot make their way from one hill to another.</p>
+
+
+<h3>THE CABBAGE BUTTERFLY.</h3>
+
+<h4><i>Pieris rapae</i> (Linn.)</h4>
+
+<p>In the New England States there are three broods
+of this insect in a year, according to Mr. Scudder, the
+butterflies being on the wing in May, July, and September;
+but as the time of the emergence varies, we
+see them on the wing continuously through the
+season.</p>
+
+<img src="images/2-fig12.png" align="right" alt="FIG. 12." title="">
+
+<p>The expanded wings, Fig. 12, male, measure about
+two inches, are white above, with the base dusky. Both
+sexes have the apex black and a black spot a little beyond
+the middle, and the female, Fig. 13, has another
+spot below this. The under side of the fore wings is
+white, yellowish toward the apex, and with two black
+spots in both sexes corresponding to those on the upper
+side of the female. A little beyond the middle of the
+costa, on the hind wings, is an irregular black spot on
+the upper surface, while the under surface is pale
+lemon yellow without marks, but sprinkled more or
+less with dark atoms. The body is black above and
+white beneath.</p>
+
+<img src="images/2-fig13.png" align="left" alt="FIG. 13." title="">
+
+<p>The caterpillars of this insect feed on the leaves of
+cabbage, cauliflower, turnip, mignonette, and some
+other plants.</p>
+
+<p>The female lays her eggs on the under side of the
+leaves of the food plants, generally, but sometimes on
+the upper sides or even on the leaf stalks. They are
+sugar loaf shaped, flattened at the base, and with the
+apex cut off square at the top, pale lemon yellow in
+color, about one twenty-fifth of an inch long and one
+fourth as wide, and have twelve longitudinal ribs with
+fine cross lines between them.</p>
+
+<p>The eggs hatch in about a week, and the young caterpillars,
+which are very pale yellow, first eat the shells
+from which they have escaped, and then spin a carpet
+of silk, upon which they remain except when feeding.
+They now eat small round holes through the leaves,
+but as they grow older change to a greenish color, with
+a pale yellow line along the back, and a row of small
+yellow spots along the sides, and eat their way down
+into the head of the cabbage.</p>
+
+<img src="images/2-fig14.png" align="right" alt="FIG. 14." title="">
+
+<p>Having reached its full growth, the caterpillar, Fig.
+14, a, which is about an inch in length, wanders off to
+some sheltered place, as under a board, fence rail, or
+even under the edge of clapboards on the side of a
+building, where it spins a button of silk, in which to
+secure its hind legs, then the loop of silk to support
+the forward part of the body.</p>
+
+<p>It now casts its skin, changing to a chrysalis, Fig. 14,
+b, about three-fourths of an inch in length, quite
+rough and uneven, with projecting ridges and angular
+points on the back, and the head is prolonged into a
+tapering horn. In color they are very variable, some
+are pale green, others are flesh colored or pale ashy
+gray, and sprinkled with numerous black dots. The
+winter is passed in the chrysalis stage.</p>
+
+<p>After the caterpillar changes to a chrysalis, their
+minute parasites frequently bore through the outside
+and deposit their eggs within. These hatch before the
+time for the butterflies to emerge, and feeding on the
+contents, destroy the life of the chrysalis.</p>
+
+<p>Birds and spiders are of great service in destroying
+these insects.</p>
+
+<p>The pupæ should be collected and burned if the
+abdomen is flexible; but if the joints of the abdomen
+are stiff and cannot be easily moved, they should be
+left, as they contain parasites.</p>
+
+<p>Several applications of poisons have been used, the
+best results being obtained from the use of pyrethrum
+as a powder blown on to the plants by a hand bellows,
+during the hottest part of the day, in the proportion
+of one part to four or five of flour.</p>
+
+<p>As the eggs are laid at different times, any application,
+to be thoroughly tested, must be repeated several
+times.</p>
+
+
+<h3>THE APPLE TREE TENT CATERPILLAR.</h3>
+
+<h4><i>Clisiocampa Americana</i> (Harr.)</h4>
+
+<p>Large, white, silken web-like tents, Fig. 15, are
+noticed by the roadsides, in the early summer, on wild
+
+cherry trees, and also on fruit trees in orchards, containing
+numerous caterpillars of a blackish color, with
+fine gray hairs scattered over the body.</p>
+
+<p>This well known pest has been very abundant
+throughout the State for several years past, and the
+trees in many neglected orchards have been greatly
+injured by it, some being entirely stripped of their
+leaves. The trees in these orchards and the neglected
+ones by the roadsides form excellent breeding places for
+this insect, and such as are of little of no value should
+be destroyed. If this were well done, and all fruit
+growers in any given region were to destroy all the
+tents on their trees, even for a single season, the work
+of holding them in check or destroying them in the
+following year would be comparatively light.</p>
+
+<img src="images/3-fig15.png" align="left"  alt="FIG. 15." title="">
+
+<p>The moths, Fig. 16, appear in great numbers in July,
+their wings measuring, when expanded, from one and a
+quarter to one and a half inches or more. They are of a
+reddish brown color, the fore wings being tinged with
+gray on the base and middle, and crossed by two
+oblique whitish stripes.</p>
+
+<img src="images/3-fig16.png" align="left" alt="FIG. 16." title="">
+
+<p>The females lay their eggs, about three hundred in
+number, in a belt, Fig. 15, c, around the twigs of apple,
+cherry, and a few other trees, the belt being covered
+by a thick coating of glutinous matter, which probably
+serves as a protection against the cold weather during
+winter.</p>
+
+<p>The following spring, when the buds begin to swell,
+the egg hatch and the young caterpillar seek some fork
+of a branch, where they rest side by side. They are
+about one-tenth of an inch long, of a blackish color,
+with numerous fine gray hairs on the body. They feed
+on the young and tender leaves, eating on an average
+two apiece each day. Therefore the young of one pair
+of moths would consume from ten to twelve thousand
+leaves; and it is not uncommon to see from six to eight
+nests or tents on a single tree, from which no less than
+seventy-five thousand leaves would be destroyed&mdash;a
+drain no tree can long endure.</p>
+
+<p>As the caterpillars grow, a new and much larger
+skin is formed underneath the old one, which splits
+along the back and is cast off. When fully grown, Fig.
+15, a and b, which is in about thirty-five to forty days
+after emerging from the eggs, they are about two
+inches long, with a black head and body, with numerous
+yellowish hairs on the surface, with a white stripe
+along the middle of the back, and minute whitish or
+yellowish streaks, which are broken and irregular along
+the sides; and there is also a row of transverse, small,
+pale blue spots along each side of the back.</p>
+
+<p>As they move about they form a continuous thread
+of silk from a fleshy tube on the lower side of the
+mouth, which is connected with the silk-producing
+glands in the interior of the body, and by means of this
+thread they appear to find their way back from the
+feeding grounds. It is also by the combined efforts of
+all the young from one belt of eggs that the tents are
+formed.</p>
+
+<p>These caterpillars do not feed during damp, cold
+weather, but take two meals a day when it is pleasant.</p>
+
+<p>After reaching their full growth, they leave their
+tents and scatter in all directions, seeking for some
+protected place where each one spins its spindle-shaped
+cocoon of whitish silk intermingled with sulphur colored
+powder, Fig. 15, d. They remain in these cocoons,
+where they have changed to pupæ, from twenty to
+twenty-five days, after which the moths emerge, pair,
+and the females lay their eggs for another brood.</p>
+
+<p>Several remedies have been suggested, a few of which
+are given below. Search the trees carefully, when
+they are bare, for clusters of eggs; and, when found,
+cut off the twigs to which they are attached, and burn
+them.</p>
+
+<p>As soon as any tents are observed in the orchard
+they should be destroyed, which may be readily and
+effectually done by climbing the trees, and with the
+hand protected by a mitten or glove, seize the tent and
+crush it with its entire contents; also swab them down
+with strong soapsuds or other substances; or tear
+them down with a rounded bottle brush.</p>
+
+<p>Burning with a torch not only destroys the caterpillars
+but injures the trees.</p>
+
+<p>It should be observed, however, since the caterpillars,
+are quite regular in taking their meals, in the
+middle of the forenoon and afternoon, that they
+
+should be destroyed only in the morning or evening,
+when all are in the tent.</p>
+
+<p>Another remedy is to shower the trees with Paris
+green in water, in the proportion of one pound to one
+hundred and fifty gallons of water.</p>
+
+<h3>THE FOREST TENT CATERPILLAR.</h3>
+
+<h4><i>Clisiocampa disstria</i> (Hübner.)</h4>
+
+<img src="images/3-fig17.png" align="right" alt="FIG. 17." title="">
+
+<p>This species, commonly known as the forest tent
+caterpillar, closely resembles the apple tree tent caterpillar,
+but does not construct a visible tent. It feeds
+on various species of forest trees, such as oak, ash,
+walnut, hickory, etc., besides being very injurious to
+apple and other fruit trees. The moth, Fig. 17, b, expands
+an inch and a half or more. The general color
+is brownish yellow, and on the fore wings are two
+oblique brown lines, the space between them being
+darker than the rest of the wing. The eggs, Fig. 17,
+c and d, which are about one twenty fifth of an inch
+long and one fortieth wide, are arranged, three or four
+hundred in a cluster, around the twigs of the trees,
+Fig. 17, a. These clusters are uniform in diameter and
+cut off squarely at the ends. The eggs are white, and
+are firmly fastened to the twigs and to each other, by
+a brown substance, like varnish, which dries, leaving
+the eggs with a brownish covering.</p>
+
+
+<p>The eggs hatch about the time the buds burst, or before,
+and the young caterpillars go for some time
+without food, but they are hardy and have been
+known to live three weeks with nothing to eat, although
+the weather was very cold.</p>
+
+<img src="images/3-fig18.png" align="left" alt="FIG. 18." title="">
+
+<p>As soon as hatched they spin a silken thread wherever
+they go, and when older wander about in search
+for food. The caterpillars are about one and a half
+inches long when fully grown, Fig. 18. The general
+color is pale blue, tinged with greenish low down on
+the sides, and everywhere sprinkled with black dots or
+points, while along the middle of the back is a row of
+white spots each side of which is an orange yellow
+stripe, and a pale, cream yellow stripe below that.
+These stripes and spots are margined with black. Each
+segment has two elevated black points on the back,
+from each of which arise four or more coarse black
+hairs. The back is clothed with whitish hairs, the head
+is dark bluish freckled with black dots, and clothed
+with black and fox-colored hairs, and the legs are
+black, clothed with whitish hairs.</p>
+
+<p>At this stage the caterpillars may be seen wandering
+about on fences, trees, and along the roads in search of
+a suitable place to spin their cocoons, which are
+creamy white, and look very much like those of the
+common tent caterpillar, except that they are more
+loosely constructed.</p>
+
+<p>Within the cocoons, in two or three days they transform
+to pupæ of a reddish brown color, densely clothed
+with short pale yellowish hairs. The moths appear in
+two or three weeks, soon lay their eggs and then die.
+The insects are not abundant many years in succession,
+as their enemies, the parasites, increase and check
+them.</p>
+
+<p>Many methods have been suggested for their destruction,
+but the most available and economical are to remove
+the clusters of eggs whenever found, and burn
+them, and to shower the trees with Paris green in the
+proportion of one pound to one hundred and fifty gallons
+of water.</p>
+
+<h3>THE STALK BORER.</h3>
+
+<h4><i>Gortyna nitela</i> (Gruen.)</h4>
+
+<p>The perfect moth, Fig. 19, 1, expands from one to
+one and a half inches. The fore wings are a mouse
+gray color, tinged with lilac and sprinkled with fine
+yellow dots, and distinguished mainly by a white band
+extending across the outer part. The moths hibernate
+in the perfect state, and in April or May deposit
+their eggs singly on the outside of the plant upon
+which the young are to feed. As soon as the eggs
+hatch, which is in about a month, the young larvæ, or
+caterpillars, gnaw their way from the outside into
+the pith.</p>
+
+<img src="images/3-fig19.png" align="right" alt="FIG. 19." title="">
+
+<p>The plant does not show any sign of decay until the
+caterpillar is fully grown, when it dies. The caterpillar,
+Fig. 19, 2, is about one and one-fourth inches long,
+of a reddish brown color, with whitish stripes along the
+body. The stripes on the sides are not continuous,
+and the shading of the body varies, being darker on
+the anterior than on the posterior portion. When
+fully grown, Fig. 20, the color is lighter and the stripes
+are broader. At this stage of life it burrows into the
+
+ground just beneath the surface, and changes into the
+pupa state. The pupa is three-fourths of an inch long,
+and of a mahogany brown color. The perfect moth
+appears about the first of September, and there is only
+one brood in a season.</p>
+
+<img src="images/3-fig20.png" align="right" alt="FIG. 20." title="">
+
+<p>The caterpillars feed in the stalks of corn, tomatoes,
+potatoes, dahlias, asters, and also in young currant
+bushes, besides feeding on many species of weeds. By
+a close inspection of the plants about the beginning of
+July, the spot where the borer entered, which is generally
+quite a distance from the ground, may be detected,
+and the caterpillar cut out without injury to the
+plant. This plan is impracticable for an extensive
+crop, but by destroying the borers found in the vines
+that wilt suddenly, one can lessen the number another
+year.</p>
+
+<h3>THE PYRAMIDAL GRAPEVINE CATERPILLAR.</h3>
+
+<h4><i>Pyrophila pyramidoides</i> (Guen.)</h4>
+
+<p>This caterpillar, Fig. 21, is generally found on grapevines
+early in June, but also feeds on apple, plum,
+raspberry, maple, poplar, etc. It is about an inch and
+a half in length, with the body tapering toward the
+head; of a whitish green color, darker on the sides;
+with a longitudinal white stripe on the back, broader
+on the last segments. Low down on each side is a
+bright yellow stripe, between this and the one on the
+back is another less distinct, and the under surface of
+the body is pale green.</p>
+
+<img src="images/3-fig21.png" align="left" alt="FIG. 21." title="">
+
+<p>The caterpillar is fully grown about the middle or
+last of June, when it descends to the ground, draws
+together some of the fallen leaves, and makes a
+cocoon, in which it soon changes to a mahogany brown
+pupa.</p>
+
+<img src="images/3-fig22.png" align="right" alt="FIG. 22." title="">
+
+<p>In the latter part of July the perfect moth, Fig. 22,
+emerges, measuring, when its wings are expanded,
+about one and three-fourths inches; the fore wings are
+dark brown shaded with lighter, with dots and wavy
+lines of dull white. The hind wings are reddish, or of
+a bright copper color, shading to brown on the outer
+angle of the front edge of the wing, and paler toward
+the hinder and inner angle.</p>
+
+<p>The under surface of the wings is lighter than the
+upper, and the body is dark brown, with its posterior
+portion banded with lines of a paler hue.</p>
+
+<p>This pest may be destroyed by hand picking, or
+by jarring the trees or vines on which they are feeding,
+when they will fall to the ground and may be crushed
+or burned.</p>
+
+<h3>THE GRAPE BERRY MOTH.</h3>
+
+<h4><i>Eudemis botrana</i> (S.V.)</h4>
+
+<p>The moths emerge and fly early in June, and are
+quite small, measuring, when the wings are expanded,
+only two-fifths of an inch, Fig. 23, a, enlarged. The
+fore wings are purplish or slate brown from the base to
+the middle, the outer half being irregularly marked
+with dark and light brown.</p>
+
+<img src="images/3-fig23.png" align="left" alt="FIG. 23." title="">
+
+<p>These insects are two-brooded and the first brood
+feeds not only on the leaves of the grape, but on tulip,
+sassafras, vernonia and raspberry. The caterpillars of
+the second brood emerge when the grapes are nearly
+grown, and bore in them a winding channel to the
+pulp, continuing to eat the interior of the berry till
+the pulp is all consumed, Fig. 23, d, when, if not full
+grown, they draw one or two other berries close to the
+first and eat the inside of those.</p>
+
+<p>The mature caterpillar, Fig. 23, b, measures about
+half an inch in length, is dull greenish, with head and
+thoracic shield somewhat darker; the internal organs
+give the body a reddish tinge. It then leaves the grape
+and forms its cocoon by cutting out a piece of a leaf,
+leaving it hinged on one side; then rolling the cut end
+over, fastens it to the leaf, thus making for itself a
+cocoon in which to pupate. The pupa is dark reddish
+brown.</p>
+
+<p>The second generation passes the winter in the pupa
+state, attached to leaves which fall to the ground;
+therefore, if all the dead and dried leaves be gathered
+in the fall and burned, also all the decayed fruit, a
+great many of these insects would be destroyed. As
+
+the caterpillars feed inside of the berry, no spraying
+of the vines with poisons would reach them. The caterpillar
+makes a discolored spot where it enters the
+berry, Fig. 23, c. Therefore the infested fruit may be
+easily detected and destroyed.</p>
+
+<p>There is a small parasite that attacks this insect and
+helps to keep it in check. The insect has been known
+in Europe over a hundred years. It is not certain
+when it was introduced into America, but it is now
+found from Canada to the Gulf of Mexico, and from
+the Atlantic to the Pacific Ocean.</p>
+
+<h3>THE CODLING MOTH.</h3>
+
+<h4><i>Carpocapsa pomonella</i> (Linn.)</h4>
+
+<p>This well known insect has a world-wide reputation,
+and is now found wherever apples are raised.</p>
+
+<img src="images/4-fig24.png" align="right" alt="FIG. 24." title="">
+
+<p>The moths are on the wing about the time the young
+apples are beginning to set, and the female lays a
+single egg in the blossom end of each apple. The fore
+wings of the moths when expanded, Fig. 24, g (f, with
+the wings closed), measure about half an inch across,
+and are marked with alternate wavy, transverse streaks
+of ashy gray and brown, and have on the inner hind
+angle a large tawny brown, horseshoe shaped spot,
+streaked with light bronze or copper color. The hind
+wings and abdomen are light brown with a luster of
+satin.</p>
+
+<p>Each female lays about fifty eggs, which are minute,
+flattened, scale-like bodies of a yellowish color. In
+about a week the eggs hatch and the tiny caterpillar
+begins to eat through the apple to the core, Fig. 24, a,
+pushing its castings out through the hole where it
+entered, Fig. 24, b. Oftentimes these are in sight on
+the outside in a dark colored mass, thus making wormy
+apples plainly seen at quite a distance.</p>
+
+<p>The caterpillar is about two-fifths of an inch in
+length, of a glossy, pale yellowish white color, with a
+light brown head. The skin is transparent and the
+internal organs give to it a reddish tinge.</p>
+
+<p>When mature the caterpillars, Fig. 24, e, top of head
+and second segment, h, emerge from the apples and
+seek some sheltered place, such as crevices of bark, or
+corners of the boxes or barrels in which the fruit is
+stored, where they spin a tough whitish cocoon, Fig.
+24, i, in which they remain unchanged all winter, and
+transform to pupæ, Fig. 24, d, the next spring, the perfect
+moths emerging in time to lay their eggs in the
+new crop of apples.</p>
+
+<p>One good remedy is to gather all the fallen apples,
+and feed them to hogs; another is to let swine and
+sheep run in the orchard, and eat the infested fruit.</p>
+
+<p>It has been recommended to place bands of cloth or
+hay around the trunks of the trees for the caterpillars
+to spin their cocoons beneath, and to remove them at
+the proper time, and put them in scalding water to
+destroy the worms.</p>
+
+<p>By far the most successful method as yet adopted is
+to shower the apple trees with Paris green in water,
+one pound to one hundred and fifty gallons of water,
+when the apples are about the size of peas, and again
+in about a week.</p>
+
+
+<h3>THE CABBAGE LEAF MINER.</h3>
+
+<h4><i>Plutella cruciferarum</i> (Zell.)</h4>
+
+<p>The cabbage leaf miner is not a native of this country,
+but was imported from Europe.</p>
+
+<img src="images/4-fig25.png" align="left" alt="FIG. 25." title="">
+
+<p>The perfect moth, Fig. 25, f, with the wings expanded
+(h, with the wings closed, g, a dark variety), measures
+three-quarters of an inch. The fore wings are
+ashy gray, and on the hinder margin is a white or yellowish
+white stripe having three points extending into
+the gray, thus forming, when the wings are closed,
+three diamond-shaped white spots. Generally there is
+a dark brown stripe between the white and the gray.
+There are also black dots scattered about on the
+anterior part of these wings.</p>
+
+<p>The hind wings are leaden brown, and the under
+side of all the wings is leaden brown, glossy, and without
+any dots.</p>
+
+<p>The antennæ are whitish with dark rings, and the
+abdomen white. There are two broods of this insect in
+this region, the moths of the first appearing in May,
+and those of the second in August. They hibernate in
+the pupa stage.</p>
+
+<p>The caterpillars, Fig. 25, a (b, the top and c, the side
+of a segment), appear in June or July and September;
+they are small and cylindrical, tapering at both ends,
+pale green, and about one-fourth of an inch long. The
+head has a yellowish tinge, and there are several dark
+stiff hairs scattered over the body.</p>
+
+<p>When ready to transform, this caterpillar spins a
+delicate gauze-like cocoon, Fig. 25, e, made of white,
+silken threads, on the under side of a cabbage leaf.
+The pupa, Fig. 25, d, and i, the end of a pupa, is commonly
+white, sometimes shaded with reddish brown,
+and can be distinctly seen through the silken case.</p>
+
+<p>The first brood is more injurious than the second, as
+it feeds on the young cabbage leaves before the head is
+formed, and this must surely stunt the growth and
+make weak, sickly plants; while the second brood
+feeds only on the outside leaves. The caterpillars are
+very active, wriggling violently when disturbed, and
+falling by a white silken thread.</p>
+
+<p>Hot dry weather is favorable to them and enables
+them to multiply rapidly. Advantage has been taken
+of this fact, and spraying the plants thoroughly with
+water is strongly recommended. Prof. Riley states
+that the insects are very readily destroyed by pyrethrum.
+There are two species of spiders and a species
+of ichneumon fly that destroy them.</p>
+
+
+<h3>THE GARTERED PLUME MOTH.</h3>
+
+<h4><i>Oxyptilus periscelidactylus</i> (Fitch.)</h4>
+
+<p>The caterpillars of this species draw together the
+young grape leaves, Fig. 26, a, in the spring, with fine
+silken threads, and feed on the inside, thus doing much
+damage in proportion to their size. These caterpillars,
+Fig. 26, a, and e, a segment greatly enlarged, are full
+grown in about two weeks, when they are about one-fourth
+of an inch long, pale green with whitish hairs
+arising from a transverse row of warts on each segment.</p>
+
+<p>Early in June they transform to pupæ, Fig. 26, b,
+which are pale green at first and change to dark brown.
+The surface is rough and the head is cut off obliquely,
+while on the upper side near the middle are two sharp
+pointed horns, Fig. 26, c. They remain in this stage
+from a week to ten days, when the moths emerge.</p>
+
+<p class="ctr">
+<img src="images/4-fig26.png" alt="FIG. 26." title="">
+</p>
+
+<p>The moths, Fig. 26, d, belong to the family commonly
+known as plume moths or feather wings
+(Pterophoridæ), from having their wings divided into
+feather-like lobes. When the wings are expanded they
+measure about seven-tenths of an inch across. They
+are yellowish brown with a metallic luster, and have
+several dull whitish streaks and spots. The fore wings
+are split down the middle about half way to their base,
+the posterior half having a notch in the outer margin.
+The body is somewhat darker than the wings.</p>
+
+<p>It is not known positively in what stage the winter
+is passed, but it is supposed to be the perfect, or imago
+stage. The unnatural grouping and spinning of the
+leaves together leads to their detection, and they can
+be easily destroyed by hand picking and then crushing
+or burning them.</p>
+
+<hr />
+
+<a name="misc-1"></a><h2>THE BREEDS OF DOGS.</h2>
+
+<p>The dog exhibitions that have annually taken place
+for the last eight years at Paris and in the principal
+cities of France have shown how numerous and varied
+the breeds of dogs now are. It is estimated that there
+are at present, in Europe, about a hundred very distinct
+and very fine breeds (that is to say, such as reproduce
+their kind with constant characters), without
+counting a host of sub-breeds or varieties that a number
+of breeders are trying to fix.</p>
+
+<p>Most of the breeds of dogs, especially those of modern
+creation, are the work of man, and have been obtained
+by intercrossing older breeds and discarding all
+the animals that departed from the type sought. But
+many of these breeds are also the result of accident, or
+rather of modifications of certain parts of the organism&mdash;of
+a sort of rachitic or teratological degeneration
+which has become hereditary and has been due to
+domestication; for it is proved that the dog is the
+most anciently domesticated animal, and that its submission
+to man dates back to more than five thousand
+years. Such is the origin of the breeds of terriers, bulldogs,
+and all of the small house dogs.</p>
+
+<p>Man has often, designedly or undesignedly, aided in
+the production of breeds of this last category by submitting
+the dog to a regimen contrary to nature, or
+setting to work to reproduce an animal born monstrous,
+either for curiosity or for interest. As well known,
+the accidental characters and the spontaneous modifications
+which work no injury to the essential functions
+of life became easily hereditary, and the same is the
+case with certain artificial modifications pursued for a
+long series of generations.</p>
+
+<p>It was the opinion of Buffon that the breeds of dogs,
+which were already numerous in his time, were all derived
+from a single type, which, according to him, was
+the shepherd's dog. Other scientists have insisted that
+the dog descended from the wolf, and others from the
+jackal. At the present time, it is rightly admitted that
+several species of wild dogs have concurred in the formation
+of the different breeds of dogs as we now have
+them.</p>
+
+<p>In the lacustrine habitations of the stone age in
+Sweden, and in the <i>kjoekkenmoedding</i> (kitchen remains)
+of Denmark, of the same epoch, we find the remains
+of a dog, which, according to Rutymeyer, belongs
+to a breed which is constant up to its least details,
+and which is of a light and elegant conformation,
+of medium size, with a spacious and rounded cranium
+and a short, blunt muzzle, and a medium sized jaw,
+the teeth of which form a regular series.</p>
+
+<p>This dog, which has been named by geologists <i>Canis
+palustris</i>, fully resembles in size, slenderness of the
+limbs, and weakness of the muscular insertions, the
+spaniel, the brach hound, or the griffon.</p>
+
+<p>This dog of the stone age is entirely distinct from the
+wolf and jackal, of which some regard the domestic
+dog as a descendant, and as it has appeared in Denmark
+as well as in Sweden, there is no doubt that this
+species, peculiar to Europe, was subjugated by man
+and used by him, in the first place, for hunting, and
+later on for guarding houses and cattle. Later still,
+in the age of metals, we observe the appearance,
+both in Denmark and Sweden, of larger and stronger
+breeds of dogs, having in their jaws the character of
+mastiffs, and probably introduced by the first emigrants
+from Asia.</p>
+
+<p>There are, moreover, historic proofs that the dogs of
+the strongest breeds are indigenous to Asia, where we
+still find the dog of Thibet, the most colossal of all; in
+fact, in Pliny we read the following narrative: Alexander
+the Great received from a king of Asia a dog of
+huge size. He wished to pit it against bears and wild
+boars, but the dog remained undisturbed and did not
+even rise, and Alexander had it killed. On hearing of
+
+this, the royal donor sent a second dog like the first,
+along with word that these dogs did not fight so weak
+animals, but rather the lion and the elephant, and
+that he had only two of such individuals, and in
+case that Alexander had this one killed, too, he would
+no longer find his equal. Alexander matched this dog
+with a lion and then with an elephant, and he killed
+them both. Alexander was so afflicted at the premature
+death of the first dog, that he built a city and
+temples in honor of the animal.</p>
+
+<p>Did the mountainous province of Epirus called
+Molossia, in ancient Greece, give its name to the
+<i>molossi</i> that it produced, or did these large dogs give
+their name to the country? At all events, we know
+that it was from Epirus that the Romans obtained the
+molossi which fought wild animals in the circuses, and
+that from Rome they were introduced into the British
+islands and have became the present mastiffs.</p>
+
+<p>Although our hunting and shepherd's dogs have a
+European and the mastiffs an Asiatic ancestry, the
+ancestry of the harriers is African, and especially
+Egyptian; in fact, in Upper Egypt we find a sort of large
+white jackal (<i>Simenia simensis</i>) with the form of a
+harrier, and which Paul Gervais regarded with some
+reason as the progenitor of the domestic harrier, and a
+comparison of their skulls lends support to this opinion.</p>
+
+<p>A study of the most ancient monuments of the
+Pharaohs shows that the ancient Egyptians already
+had at least five breeds of dogs: two very slim watch
+dogs, much resembling the harrier, a genuine harrier,
+a species of brach hound and a sort of terrier with
+short and straight legs. All these dogs had erect ears,
+except the brach, in which these organs were pendent,
+and this proves that the animal had already undergone
+the effects of domestication to a greater degree
+than the others. The harrier of the time of the
+Pharaohs still exists in great numbers in Kordofan, according
+to Brehm.</p>
+
+<p>Upon the whole, we here have, then, at least three
+stocks of very distinct dogs: 1, a hunting or shepherd's
+dog, of European origin; 2, a mastiff, typical of the
+large breed of dogs indigenous to Asia; and 3, a harrier,
+indigenous to Africa.</p>
+
+<p>We shall not follow the effects of the combination of
+these three types through the ages, and the formation
+of the different breeds; for that we shall refer our
+readers to a complete work upon which we have been
+laboring for some years, and two parts of which have
+already appeared.<a name="FNanchor_1"></a><a href="#Footnote_1"><sup>1</sup></a></p>
+
+<p>We shall rapidly pass in review the different breeds
+of dogs that one may chance to meet with in our dog
+shows, beginning with the largest. It is again in mountainous
+countries that the largest dogs are raised, and
+the character common to all of these is a very thick
+coat. The largest of all, according to travelers, is the
+Thibetan dog. Buffon tells of having seen one which,
+when seated, was five feet in height. One brought
+back by the Prince of Wales from his voyage to the
+Indies was taller in stature, stronger and more stocky
+than a large mastiff, from which it differed, moreover,
+in its long and somewhat coarse hair, which was
+black on the back and russet beneath, the thighs and
+the tail being clothed with very long and silky hair.</p>
+
+<p>In France, we have a beautiful mountain dog&mdash;the
+dog of the Pyrenees&mdash;which is from 32 to 34 inches in
+height at the shoulders, and has a very thick white
+coat, spotted above with pale yellow or grayish fox
+color. It is very powerful, and is capable of successfully
+defending property or flocks against bears and
+wolves.</p>
+
+<p>The Alpine dog is the type of the mountain dog. It
+is of the same size as the dog of the Pyrenees, and differs
+therefrom especially in its coloring. It is white
+beneath, with a wide patch of orange red covering
+the back and rump. The head and ears are of the
+same color, with the addition of black on the edges;
+but the muzzle is white, and a stripe of the same color
+advances upon the forehead nearly up to the nape of
+the neck. The neck also is entirely white. There are
+two varieties of the Alpine or St. Bernard dog, one
+having long hair and the other shorter and very thick
+hair. We give in Fig. 1 a portrait of Cano, a large
+St. Bernard belonging to Mr. Gaston Leonnard.</p>
+
+<p class="ctr"><a href="./images/4-fig1.png">
+<img src="images/4-fig1-th.jpg" alt="FIG.1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD." title="">
+</a><br clear="all" />FIG.1&mdash;LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.</p>
+
+<p>Although this breed originated at the celebrated
+convent of St. Bernard, it no longer exists there in a
+state of purity, and in order to find fine types of it we
+have to go to special breeders of Switzerland and England.
+The famous Plinnlimon, which was bought for
+$5,000 by an American two or three years ago, and
+about which there was much talk in the papers, even
+the political ones, was born and reared in England.
+It appears that it is necessary, too, to reduce the number
+of life-saving acts that it is said are daily performed
+by the St. Bernard dogs. This is no longer but a
+legend. There was, it is true, a St. Bernard named
+Barry, now exhibited in a stuffed state in the Berne
+Museum, which accomplished wonders in the way of
+saving life, but this was an exception, and the reputation
+of this animal has extended to all others of its
+kind. These latter are simply watch dogs kept by the
+monks for their own safety, and which do not go at all
+by themselves alone to search for travelers that have
+lost their way in the snow.</p>
+
+<p>The Newfoundland dog, which differs from the preceding
+in its wholly black or black and white coat,
+was, it appears, also of mountain origin. According
+to certain authors, it is indigenous to Norway, and was
+carried to Newfoundland by the Norwegian explorers
+who discovered the island. Adapted to their new existence,
+they have become excellent water dogs, good
+swimmers, and better life savers by far than the majority
+of their congeners.</p>
+
+<p>Is it from descending to the plain that the mountain
+dogs have lost their long hair and have become short
+haired dogs like the English dog or mastiff and the
+German or large Danish dogs? It is very probable.
+At all events, it is by this character of having short
+hair that mastiffs are distinguished from the mountain
+dogs. Again, the large breed of dogs are distinguished
+from each other by the following characters: The mastiff
+is not very high at the shoulders (30 inches), but he
+is very heavy and thick set, with powerful limbs, large
+head, short and wide muzzle and of a yellowish or café-au-lait
+color accompanying a black face; that is to say,
+the ears, the circumference of the eyes and the muzzle
+are of a very dark color. The German or large Danish
+dogs constitute but one breed, but of three varieties,
+according to the coat: (1) those whose coat is of a
+uniform color, say a slaty gray or isobelline of varying
+depth, without any white spots; (2) those having a
+fawn colored coat striped transversely with black like
+the zebra, but much less distinctly; (3) those having a
+spotted coat, that is to say, a coat with a white ground
+strewed with irregular black spots of varying size.
+These, like those of the first variety are generally small-eyed.
+Whatever be the variety to which they belong,
+the German or large Danish dogs are slimmer than,
+and not so heavy as, the mastiffs. Some, even, are so
+light that it might be supposed that they had some
+heavier blood in their veins. They have also a longer
+muzzle, although square, and are quicker in gait and
+motions.</p>
+
+<p>The largest dogs are to be met with in this breed, and
+the beautiful Danish dog belonging to Prof. Charcot
+(Fig. 2) is certainly the largest dog in France and perhaps
+in Europe. It measures 36 inches at the shoulders
+and has an osseous and muscular development
+perfectly in keeping with its large stature, and at the
+same time has admirable proportions and lightness,
+and its motions are comparable to those of the finest
+horse.</p>
+
+<p class="ctr"><a href="./images/4-fig2.png">
+<img src="images/4-fig2-th.jpg" alt="FIG. 2" title="">
+</a><br clear="all" />FIG. 2&mdash;DR. CHARCOT'S LARGE DANISH DOG.</p>
+
+<p>Among the English dogs or mastiffs, we very frequently
+meet with individuals in which the upper incisors
+and canines are placed back of the corresponding
+ones in the lower jaw, this being due to a slight shortening
+of the bones of the upper jaw, not visible externally.
+This is the first degree of an artist of teratological
+development, which, since the middle ages,
+has become very marked in certain subjects, and has
+given rise to a variety in which this defect has become
+hereditary. Such is the origin of the breed of bulldogs.
+The latter were originally as large as the mastiffs.
+Carried to Spain under Philip II., they have
+there preserved their primitive characters, but the bulldogs
+remaining in England have continued to degenerate,
+so that now the largest are scarcely half the
+size of the Spanish bulldog, and the small ones attain
+hardly the size of the pug, although they preserve
+considerable width of chest and muscular strength.</p>
+
+<h3>POINTERS.</h3>
+
+<p>Man hunted for ages with dogs that he united in a
+pack; but these packs were of a very heterogeneous
+composition, since they included strong dogs, light dogs
+very swift of foot, shepherds' dogs, and others noted for
+acuteness of scent, and even mongrels due to a crossing
+with the wolf. It is from the promiscuousness of all
+these breeds that has arisen our ordinary modern
+dog.</p>
+
+<p>The pointer is of relatively recent creation, and is due
+to the falconers. In our western countries, falconry
+dates from the fourth and fifth centuries, as is proved
+by the capitularies of Dagobert. This art, therefore,
+was not brought to us from the East by the crusaders
+in the twelfth and thirteenth centuries, as stated by Le
+Maout in his Natural History of Birds.</p>
+
+<p>The falconer soon saw the necessity of having a dog
+of nice scent having for its role the finding or hunting
+up of game without pursuing it, in order to permit the
+falcons themselves to enter into the sport. This animal
+was called the bird dog, and was regarded as coming
+
+from various countries, especially from Spain,
+whence the name of spaniel that a breed of pointers
+has preserved. It is quite curious to find that for three
+or four centuries back there have been no spaniels in
+Spain. From Italy also and from southern climes
+comes what is called the <i>bracco</i>, whence doubtless is
+derived the French name <i>braque</i> and English brach.
+Finally the <i>agasse</i> of the Bretons was certainly also
+one of the progenitors of our present pointers. It was,
+says Oppian, a breed of small and very courageous
+dogs, with long hair, provided with strong claws and
+jaws, that followed hares on the sly under shelter of
+vine-stocks and reeds and sportively brought them
+back to their masters after they had captured them.
+We have certainly here the source of our barbets and
+griffons.</p>
+
+<p>Finally the net hunters of the middle ages also contributed
+much to the creation of the pointer, for it is
+to them that we owe the setter. It is erroneously, in
+fact, that certain authors have attributed the creation
+of this dog to hunters with the arquebuse, since
+this weapon did not begin to be utilized in hunting
+until the sixteenth century. Gaston Phoebus, who
+died in 1391, shows, in his remarkable work, that the
+net hunters made use of Spanish setters and that it
+was they who created the true pointer&mdash;the animal that
+fascinates game by its gaze. By the same pull of their
+draw net they enveloped in its meshes both the setter
+and the prey that it held spellbound.</p>
+
+<p>Upon the whole, we see that at the end of the middle
+ages there existed three types of pointers: spaniels,
+brachs and very hairy dogs, that Charles Estienne,
+in his Maison Rustique, of the sixteenth century, calls
+barbets. It is again with these three types that are
+connected all the present pointers, which we are going
+to pass rapidly in review.</p>
+
+<p><i>The Brach hounds</i>.&mdash;To-day we reserve the name of
+brachs for all pointers with short hair. The type of
+the old brach still exists in Italy, Spain, the south of
+France and in Germany. It is characterized by its
+large size, its robust form, its large head, its long, flat
+ears, its square muzzle separated from the forehead by
+a deep depression, its large nose, often double (that
+is to say, with nostrils separated by a deep vertical
+groove), its pendent lips, its thick neck, its long and
+strong paws provided with dew claws, both on the fore
+and the hind feet, and its short hair, which is usually
+white and marked with brown or orange-yellow spots.
+The old brach breed has been modified by the breeders
+of different countries, either by hygiene or by crossing
+with ordinary dogs, according to the manner of
+hunting, according to taste, and even according to
+fashion. Thus in England, where "time is money"
+reigns in every thing and where they like to hunt quickly
+and not leisurely, the brach has been rendered
+lighter and swifter of foot and has become the pointer.
+In France, while it has lost a little in size and weight,
+it has preserved its moderate gait and has continued to
+hunt near its master, "under the gun," as they say.
+The same is the case in Spain, Italy and Germany
+even. In France there are several varieties or sub-breeds
+of brach hounds. The old French brach, which
+is nothing more than the old type, preserved especially
+in the south, where it is called the Charles the
+Tenth brach, is about twenty-four inches in height,
+and has a white and a maroon coat, which is somewhat
+coarse. It often has a cleft nose and dew-claws on all
+the feet. The brach of the south scarcely differs from
+the preceding except in color. Its coat has a white
+ground covered with pale orange blotches and spots
+of the same color. The St. Germain brach is finer
+bred, and appears to be a pointer introduced into
+France in the time of Charles X. It has a very fine
+skin, very fine hair of a white and orange color. The
+Bourbon brach has the characters of the old French
+brach, with a white coat marked here and there with
+large brown blotches, and the white ground spotted
+with the same color; but what particularly characterizes
+this dog is that it is born with a stumpy tail, as if
+three-quarters of it had been chopped off. The Dupuy
+brach is slender and has a narrow muzzle, as if it had
+some harrier blood in its veins. It is white, with large
+dark maroon blotches. The Auvergne brach resembles
+the southern brach, but has a white and black
+coat spotted with black upon white. The pointer, or
+English brach (Fig. 3), descends from the old Spanish
+brach, but has been improved and rendered lighter and
+much swifter of foot by the introduction of the blood
+of the foxhound into its veins, according to the English
+cynegetic authors themselves. The old pointer
+was of a white and orange color, and was indistinguishable
+from our St. Germain. The pointer now fancied
+is white and maroon and has a stronger frame than the
+pointer of twenty years ago. The Italian brachs are
+heavy, with lighter varieties, usually white and orange
+color, more rarely <i>roan</i>, and provided with dew-claws,
+this being a sign of purity of breed according to Italian
+fanciers. The German brachs are of the type of the
+old brach, with a stiff white and maroon coat, the latter
+color being so extensively distributed in spots on
+the white as to make the coat very dark.</p>
+
+<p class="ctr">
+<img src="images/5-fig3.png" alt="FIG 3.--POINTER." title="">
+<br clear="all" />FIG 3.&mdash;POINTER.</p>
+
+<p><i>Spaniels</i>.&mdash;The old type of spaniel has nearly disappeared,
+yet we still find a few families of it in France,
+especially in Picardy and perhaps in a few remote parts
+of Germany. The old spaniel was of the same build as
+the brach, and differed from it in that the head, while
+being short-haired, was provided with ears clothed with
+long, wavy hair. The same kind of hair also clothed
+the whole body up to the tail, where it constituted a
+beautiful tuft. The Picard spaniel is a little lighter
+than the old spaniel. It has large maroon blotches upon
+a white ground thickly spotted with maroon, with a
+touch of flame color on the cheeks, over the eyes, and
+on the legs. The Pont-Andemer spaniel is a Norman
+variety, with very curly hair, almost entirely maroon
+colored, the white parts thickly spotted with a little
+color as in the Picard variety, and a characteristic forelock
+on the top of the head.</p>
+
+<p class="ctr"><a href="./images/5-fig4.png">
+<img src="images/5-fig4-th.jpg" alt="FIG 4.--ENGLISH SETTERS." title="">
+</a><br clear="all" />FIG 4.&mdash;ENGLISH SETTERS.</p>
+
+<p>In England, the spaniel has given rise to several varieties.
+In the first place there are several sub-breeds of
+setters, viz.: The English setter, still called laverack,
+which has large black or orange-colored blotches on
+the head, the rest of the body being entirely white,
+with numerous spots of the same color as the markings
+on the head (Fig. 4); the Irish setter, which is entirely
+of a bright yellowish mahogany color; and the Gordon
+setter, which is entirely black, with orange color on
+the cheeks, under the throat, within and at the extremity
+of the limbs (Fig. 5). Next come the field spaniels,
+a group of terrier spaniels, which includes the Clumber
+spaniel, which is white and orange color; the Sussex
+spaniel, which is white and maroon; the black spaniel,
+which is wholly black; and the cocker, which is the
+smallest of all, and is entirely black, and white and
+maroon, or white and orange-colored, or tricolored.</p>
+
+<p class="ctr">
+<img src="images/6-fig5.png" alt="FIG 5.--GORDON SETTER." title="">
+<br clear="all" />FIG 5.&mdash;GORDON SETTER.</p>
+
+<p><i>Barbets and Griffons</i>.&mdash;To this latter category belong
+the dogs, <i>par excellence</i>, for hunting in swamps. The
+barbets are entirely covered with long curly hair, like
+the poodles, which are directly derived from them.
+They are white or gray, with large black or brown
+blotches. The griffons differ from the poodles in their
+coarse and stiff hair, which never curls. They have
+large brown blotches upon a white ground, which is
+much spotted or mixed, as in the color of the hair
+called roan. There is an excellent white and orange-colored
+variety. The griffons, neglected for a long
+time on account of the infatuation that was and is still
+had for English hunting dogs, are being received again
+with that favor which they have never ceased to be the
+object of in Germany and in Italy (where they bear the
+name of <i>spinone</i>). Breeders of merit, such as Mr. Korthals,
+in Germany, and Mr. E. Boulet, in France, are
+endeavoring to bring them into prominence (Fig. 6). Finally,
+we reckon also among hunting dogs some very
+happy crosses between the spaniels and the barbets,
+which in England are called retrievers or water
+spaniels.&mdash;<i>P. Megnin, in La Nature</i>.</p>
+
+<p class="ctr">
+<img src="images/6-fig6.png" alt="FIG 6.--COARSE HAIRED GRIFFON." title="">
+<br clear="all" />FIG 6.&mdash;COARSE HAIRED GRIFFON.</p>
+
+<a name="Footnote_1"></a><a href="#FNanchor_1">[1]</a><div class="note">Les Races des Chiens, in La Bibliotheque de l'Eleveur.</div>
+
+<hr />
+
+<a name="pisc-1"></a><h2>RESTOCKING THE SEINE WITH FISH.</h2>
+
+<p>A few days ago, at Bougival, a short distance below
+the dam of the Marly machine, there were put into
+water 40,000 fry of California trout and salmon, designed
+to restock the Seine, which, in this region, has
+been depopulated by the explosions of dynamite which
+last winter effected the breaking up of the ice jam
+that formed at this place.</p>
+
+<p class="ctr"><a href="./images/6-a.png">
+<img src="images/6-a-th.jpg" alt="RESTOCKING THE SEINE WITH FISH." title="">
+</a><br clear="all" />RESTOCKING THE SEINE WITH FISH.</p>
+
+<p>The operation, which is quite simple in itself, attracted
+a large number of inquisitive people by reason
+of the exceptional publicity given to the conflict provoked
+by a government engineer, who, under the pretext
+that he had not been consulted, made objections
+to the submersion of the little fish. As well known,
+the affair was terminated by a sharp reprimand from
+Mr. Yves Guyot, addressed to his overzealous subordinate.</p>
+
+<p>It would have been a great pity, moreover, if this interesting
+experiment had not taken place, and had not
+come to corroborate the favorable results already obtained.</p>
+
+<p>In three years the California salmon reaches a weight
+of eleven pounds, and, from this time, is capable of reproduction.
+Its flesh is delicious, and comparable to
+that of the trout, the development of which is less rapid,
+but just as sure.</p>
+
+<p>The fry put into the water on Sunday were but two
+months old. The trout were, on an average, one and a
+half inches in length, and the salmon two and three-quarter
+inches. They were transported in three iron
+plate vessels, weighing altogether, inclusive of the
+water, 770 lb., and provided with air tubes through
+which, during the voyage, the employes, by means of
+pumps, assured the respiration of the little fish.</p>
+
+<p>Our engraving represents the submersion at the
+moment at which the cylinders (of which the temperature
+has just been taken and compared with that of
+the Seine, in order to prevent too abrupt a transition
+for the fry) are being carefully let down into the river.&mdash;<i>L'Illustration</i>.</p>
+
+<hr />
+
+<p>Figures show that the consumption of iron in general
+construction&mdash;other than railroads&mdash;in this country
+has grown from a little more than a million and a half
+of tons in 1879 to more than six million tons in 1889.
+Much of this increase has gone into iron buildings. By
+using huge iron frames and thin curtain walls for each
+story supported thereon, as is done in a building going
+up on lower Broadway, New York city, a good deal of
+space can be saved.</p>
+
+<hr />
+<a name="nav-1"></a><h2>MODERN ARMOR.</h2>
+
+<h3>By F.R. BRAINARD, U.S.N.</h3>
+
+<p>The building of a navy, which has been actively
+going on for the past few years, has drawn public attention
+to naval subjects, and recent important experiments
+with armor plates have attracted large attention,
+hence it may not be amiss to give a description
+of the manufacture and testing of armor. It would be
+interesting to wade through the history of armor,
+studying each little step in its development, but we
+shall simply take a hasty glance at the past, and then
+devote our attention to modern armor and its immediate
+future.</p>
+
+<p>Modern armor has arrived at its present state of development
+through a long series of experiments. These
+experiments have been conducted with great care and
+skill, and have been varied from time to time as the
+improvements in the manufacture of materials have
+developed, and as the physical laws connected with
+the subject have been better understood. There has
+been very little war experience to draw from, and
+hence about all that is now known has been acquired
+in peaceful experiments.</p>
+
+<p>The fundamental object to be obtained by the use of
+armor is to keep out the enemy's shot, and thus protect
+from destruction the vulnerable things that may
+be behind it. The first serious effort to do this dates
+with the introduction of iron armor. With this form
+of armor we have had a small amount of war experience.
+The combat of the Monitor and Merrimac, in
+Hampton Roads, in May, 1862, not only marked an
+epoch in the development of models of fighting ships,
+but also marked one in the use of armor. The Monitor's
+turret was composed of nine one-inch plates of
+wrought iron, bolted together. Plates built in this
+manner form what is known as laminated armor.
+(See Fig. 1.)
+<img src="images/7-fig1.png" align="left" alt="Fig. 1. Laminated" title="">
+The side armor of the hull was composed
+of four one-inch plates. The Merrimac's casemate was
+composed of four one-inch plates or two two-inch plates
+backed by oak. The later monitors had laminated armor
+composed of one-inch plates. The foregoing, with
+the Albemarle and Tennessee rams under the Confederate
+flag, are about the sum of our practical experience
+in the use of armor.</p>
+
+
+<p>European nations took up the subject of armor and
+energetically conducted experiments which have cost
+large sums of money, but have given much valuable
+data. For a long time wrought iron was the only material
+used for armor, and the resisting power depending
+on the thickness; and the caliber and penetration
+of guns rapidly increasing, it was not long before a
+point was reached where the requisite thickness made
+the load of armor so great that it was impracticable for
+a ship to carry it. The question then arose as to what
+were the most important parts of a ship to protect.
+The attempted solutions of this question brought out
+various systems of distributions.</p>
+
+<p>Armored ships were formerly of two classes; in one
+the guns were mounted in broadside, in the other in
+turrets. Every part of the ship was protected with
+iron to a greater or less thickness. In more modern
+ships the guns are mounted in an armored citadel, in
+armored barbettes or turrets, the engines, boilers and
+waterline being the only other parts protected. There
+may be said to be three systems of armor distribution.
+The belt system consists in protecting the whole waterline
+by an armored belt, the armor being thickest
+abreast of the engines and boilers. The guns are protected
+by breastworks, turrets or barbettes, the other
+parts of the ship being unprotected. The French use
+the belt system, and our own monitors may be classed
+under it. The central citadel system consists in armoring
+that part of the waterline which is abreast of
+the engines and boilers. Forward and aft the waterline
+is unprotected, but a protective deck extends from
+the citadel in each direction, preventing the projectiles
+from entering the compartments below. The hull is
+divided into numerous compartments by water-tight
+bulkheads, and, having a reserve of flotation, the stability
+of the ship is not lost, even though the parts
+above the protective deck, forward and aft, be destroyed
+or filled with water. The guns are protected
+by turrets or barbettes. The deflective system consists
+in inclining the armor, or in so placing it that it
+will be difficult or impossible to make a projectile
+strike normal to the face of the plate. A plate that is
+inclined to the path of a projectile will, of course, offer
+greater resistance to penetration than one which is
+perpendicular; hence, when there is no other condition
+to outweigh this one, the armor is placed in such a
+manner as to be at the smallest possible angle with
+the probable path of the projectile. This system is designed
+to cause the projectile to glance or deflect on
+impact. Deflective armor should be at such an angle
+that the projectiles fired at it cannot bite, and hence
+the angle will vary according to the projectile most
+likely to be used. In the usual form of deflective deck
+the armor is at such a small inclination with the horizon
+that it becomes very effective. Turret and
+barbette armor may be considered as deflective armor.
+The term inclined armor denotes deflective armor
+that is inclined to the vertical. The kinds of armor
+that are in use may be designated as rolled iron, chilled
+cast iron, compound, forged and tempered steel, and
+nickel steel. Iron armor consists of wrought iron
+plates, rolled or forged, and of cast iron or chilled cast
+iron, as in the Gruson armor. Compound armor consists
+of a forged combination of a steel plate and an
+iron plate. Steel armor consists of wrought steel
+plates. Nickel-steel armor consists of plates made
+from an alloy of nickel and steel.</p>
+
+<p>I have spoken above of laminated armor. To secure
+the full benefit of this kind, the plates must be neatly
+fitted to each other; the surfaces must make close contact.
+This requires accurate machining, and hence is
+expensive. To overcome this point sandwiched armor
+was suggested. This consists in placing a layer of wood
+between the laminations, as shown in Fig. 2.
+<img src="images/7-fig2.png" align="right" alt="Fig. 2." title="">
+It was
+found that laminated and sandwiched armor gave very
+much less resisting power than solid rolled plates
+of the same thickness. Wrought iron armor is made
+under the hammer or under the rolls, in the ordinary
+manner of making plates, and has been exhaustively
+studied and experimented with&mdash;more so than any
+other form of armor.</p>
+
+
+<p>Chilled cast iron armor is manufactured by Gruson,
+in Germany, and is used in sea coast defense forts of
+Europe.</p>
+
+<p>In 1867 several compound plates were made by Chas.
+Cammell &amp; Co., of Sheffield, England, and were tested
+at Shoeburyness, in England, and at Tegel, in Russia.
+These plates were made by welding slabs of steel to
+iron; but the difficulties were so great that the idea
+was abandoned for the time.</p>
+
+<p>
+<img src="images/7-fig3.png" align="left" alt="Fig. 3." title="">
+
+<img src="images/7-fig4.png" align="right" alt="FIG. 4." title="">
+<br clear="all" /></p>
+
+<p>Compound armor, as now manufactured, is of two
+types: Wilson's patent, a backing of rolled iron, faced
+with Bessemer steel; Ellis' patent, a backing of rolled
+iron, faced with a plate of hard rolled steel, cemented
+with a layer of Bessemer steel. Both these kinds are
+manufactured in England and France in sizes up to
+fifty tons weight. The Wilson process is used at the
+works of Messrs. Cammell &amp; Co., of Sheffield, England,
+and the Ellis process at the Atlas Works of Sir John
+Brown &amp; Co., of the same place. These are the two
+leading manufacturers of compound plate.</p>
+
+
+<p>The method employed by Wilson in making compound
+plate is to first make a good wrought iron
+plate. To the surface of this and along each side of
+the length of the plate are fixed two small channel
+irons, as shown in Fig. 5.
+<img src="images/7-fig5.png" align="left" alt="Fig. 5." title="">
+The plate is then raised to
+a welding heat in a gas furnace, and transferred to an
+iron flask or mould. Wedges are driven in between
+the back of the plate and the side of the mould, thus
+forcing the channel irons up snug against the opposite
+side of the mould. Moulding sand is then packed
+around the back and sides of the plate (see Fig. 6).
+<img src="images/7-fig6.png" align="right" alt="Fig. 6." title="">
+The
+mould is lowered in a vertical position into a pit.
+Molten steel, manufactured by either the Siemens-Martin
+or Bessemer process, is then poured in through
+a trough that forms several streams, and forms the
+hard face of the plate. The molten steel as it runs
+down cleans the face of the wrought iron plate, scoring
+it in places, and, being of much higher temperature,
+the excessive heat carbonates the iron to a depth
+of one-eighth to three-sixteenths of an inch, forming
+a zone of mild steel between the hard steel and soft
+iron. The mould is placed in a vertical position to insure
+closeness of structure and the forcing of gases
+out of the steel. After solidifying, the whole plate is
+pressed, and passed through the rolls to obtain
+thorough welding. It is then bent, planed, fitted,
+tempered, and annealed to remove internal strains.</p>
+
+<p>In 1887, Wilson took out a patent for improvements
+in his process of making compound plates. In this
+method of manufacture he takes a wrought iron,
+fibrous plate, fifteen inches thick, built up from a
+number of thin plates. While hot from the forging
+press, he places this plate in an iron mould (see Fig. 7)
+<img src="images/7-fig7.png" align="left" alt="Fig. 7." title="">
+about 28 inches deep, and upon it runs "ingot iron"
+or very mild steel to a depth of thirteen inches. In
+this form of mould the plate rests on brickwork, and is
+held in place by two grooved side clamps or strips which
+are caused to grip the plate by means of screws which
+extend through the sides of the mould. After solidifying,
+the plate, which is twenty-eight inches thick, is
+reheated and rolled down to eighteen inches. This is
+the iron backing of the finished plate, and it is again
+put in the iron mould and heated, when a layer of hard
+steel is run on the exposed surface of the original
+wrought iron plate to a depth of eight inches. This
+makes a plate about twenty-eight inches thick. It is
+taken from the mould, reheated, rolled, hammered or
+pressed down to twenty inches. After cooling, it is
+bent, planed, and fitted as desired, then tempered and
+annealed to relieve internal strains.</p>
+
+
+
+<p>The method employed by Ellis in making compound
+plates is to take two separate plates, one of good
+wrought iron and one of hard forged steel, placing the
+forged steel plate on the wrought iron plate, keeping
+them separate by a wedge frame or berm of steel
+around three sides, and placing small blocks of steel at
+various points near the middle of the plates (see Fig. 8).
+<img src="images/7-fig8.png" align="right" alt="Fig. 8." title="">
+These blocks are called distance blocks. After covering
+all the exposed steel surfaces with ganister, the
+plates are put in a gas furnace and heated to a welding
+heat. They are then lowered into a vertical iron pit
+with the open side uppermost. The plates are held in
+position by hydraulic rams, which also prevent bulging.
+Molten steel of medium softness is then poured
+into the space between the plates, by means of a distributing
+trough having holes in the bottom, and after
+this has solidified, the whole plate is placed under the
+hydraulic press and reduced about twenty per cent. in
+thickness. The plate is then passed through the rolls,
+bent, planed, fitted, tempered, and annealed to reduce
+internal strains.</p>
+
+<p>In heating the compound plates for rolling, the plate
+is placed in the furnace with the steel face down, so
+that the iron part gets well heated and the steel does
+not become too hot. Great care must be taken not to
+overheat the plate, and in working, many passes are
+given the plate with small closings of the rolls. The
+steel part of a compound plate is usually about one
+third of the full thickness of the plate.</p>
+
+<p>Forged steel armor, tempered in oil, is fabricated at
+Le Creusot, France, by Schneider &amp; Co., using open-hearth
+steel, and forging under the 100 ton hammer.
+
+The ingots are cast, with twenty-five per cent. sinking
+head and are cubical in form. The porter bar is attached
+to a lug on one side of the ingot. By means of
+a crane with a curved jib which gives springiness under
+the hammer, the ingot is thrust into the heating
+furnace. On arriving at a good forging heat it is
+swung around to the 100 ton hammer, under which it is
+worked down to the required shape. A seventy-five
+ton ingot requires about eight reheatings before being
+reduced to shape. Having been reduced to shape, the
+plate is carefully annealed, then raised to a high tempering
+heat, and the face tempered in oil. It is reannealed
+to take out the internal strains, care being taken
+not to reduce the face hardness more than necessary.
+The Schneider process of tempering is based upon the
+utilization of the absorption of heat caused by the fusing
+or melting of a solid substance, and of the fact
+that so long as a solid is melting or dissolving in a
+liquid substance, the liquid cannot get appreciably
+hotter, except locally around the heating surface. The
+body to be hardened is plunged at the requisite temperature
+into a bath containing the solid melting body,
+or is kept under pressure in the solid material of low
+melting point until the required extraction of heat has
+taken place, more solid material being added if necessary
+as that originally present melts and dissolves.</p>
+
+<p>Nickel steel armor is made in a similar manner to
+the steel plates, the material used in casting the ingot
+being an alloy of nickel and steel containing between
+three and four per cent. of nickel.</p>
+
+<p>The Harvey process of making armor consists in taking
+an all-steel plate and carbonizing the face. This
+carbonizing process is very similar to the cementation
+process of producing steel, and by it the face of the
+plate is made high in carbon and very hard.</p>
+
+<p>The system invented by Sir Joseph Whitworth, of
+Manchester, England, consists in what might be called
+scale armor. A section of a sample of the armor represents
+four plates. The outer layer, one inch thick, is
+composed of steel of a tensile strength of 80 tons per
+square inch; the second layer, one inch thick, of steel
+whose tensile strength is 40 tons per square inch; the
+third and fourth layers, each one-half inch thickness,
+of mild steel. The outer layer is in small squares of
+about ten inches on a side, and is fastened to the second
+layer by bolts at the corners and one in the middle of
+each square. The surface is flush. (See Fig. 9.)
+<img src="images/8-fig9.png" align="right" alt="Fig. 9." title="">
+The
+end sought by the above system is to break up the shot
+by the hard steel face and to restrict any starring or
+cracking of the metal to the limit of the squares or
+scales struck. The bolts are of high carbon and are
+extremely hard steel.
+</p>
+
+<p>Armor plates must often be bent or curved to single
+or double curvature and sometimes to a warped surface
+to fit the form of the ship. There are several methods
+of bending plates. One method employs a cast iron
+slab of the required form, which is placed on the piston
+of a hydraulic press. The armor plate is placed
+face down on this slab, and on top of the plate are laid
+packing blocks of cast iron, of such sizes and shapes as
+to conform to the required curve. These blocks take
+against the upper table of the press, when the piston
+is forced up, and the hot plate is thus dished to the
+proper form.</p>
+
+<p>In the French method of bending, an anvil or bed
+plate of the required curve is used, and the armor plate
+is forced to take the curve by being hammered all over
+its upper surface with a specially designed steam
+hammer.</p>
+
+<p>The edges of the plate are trimmed by large, powerful
+slotting machines or circular saws; the latter, however,
+operate in exactly the same manner as a slotter,
+except that there is no return motion to the tool. Each
+tooth of the saw is but a slotting tool, and these teeth
+are, by screws, rendered capable of being nicely adjusted
+in the circumference of the saw.</p>
+
+<p>The plates are fastened to the hulls and backing by
+heavy bolts, varying in size according to the weight of
+the individual plate. For the 6,000 ton armored ships,
+these bolts are from 2.75 to 3.1 inches in diameter and
+from 18.45 to 23 inches in length. They are tapped
+two or three inches into the armor and do not go
+through the plate. They pass through wrought iron
+tubes in the backing and set up with cups, washers
+and nuts against the inner skin of the ship.</p>
+
+<p>At steel works where plates for our new navy are
+being manufactured, there are inspectors who look
+after the government's interests. Officers of the navy
+are detailed for this work, and their duty is to watch
+the manufacture of plates through each part of the
+process and to see that the conditions of the specifications
+and contract are complied with.</p>
+
+
+<p>The inspection and testing of armor plates consists
+in examining them for pits, scales, laminations, forging
+cracks, etc., in determining the chemical analysis of
+specimens taken from different parts, in determining
+the physical qualities of specimens taken longitudinally
+and transversely, and the ballistic test. Specifications
+for these different tests are constantly undergoing
+change, and it would be impossible to state, with exactness,
+what the requirements are or will be in the near
+future. The ballistic test is the important one,
+and is made by taking one plate of a group and subjecting
+it to the fire of a suitable gun. The other tests
+are simply to insure, as far as practicable, that all the
+other plates of the group are similar to and are capable
+of standing as severe a ballistic test as the test plate.</p>
+
+<p>The following will give an idea of the ballistic test
+as prescribed by the Bureau of Ordnance, Navy Department.
+The test plate, irrespective of its thickness,
+is to be backed by thirty-six inches of oak or other
+substantial wood. Near the middle region of the plate an
+equilateral triangle will be marked, each side of which
+will be three and one-half calibers long. The lower
+side of the triangle will be horizontal. Three shots
+will be fired, the points of impact being as near as possible
+the extremities of the triangle. The velocity of
+the shot will be such as to give the projectile sufficient
+energy to just pass through a wrought iron plate of
+equal thickness to the test plate, and through its wood
+backing. The velocity is calculated by the Gavre
+formula:</p>
+
+<p><img src="./images/tex1.png" align="middle" alt=
+"V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}"></p>
+
+<p class="ind">V = the velocity of the projectile in feet per second.<br />
+  a = the diameter of the projectile in inches.<br />
+  w = the weight of the projectile in pounds.<br />
+  E = the thickness of the backing in inches.<br />
+  e = the thickness of the plate in inches.<br />
+</p>
+
+<p>Using the above formula we can make out a table as follows:</p>
+
+<pre>
+-------+-------+-------------+-------+-------+------+---------+
+Plate. |Backi'g| Gun, service|  w,   |  a,   |  V.  | Energy, |
+Inches.|Inches.| shot.       |Pounds.|Inches.| f. 8.| Impact. |
+       |       |             |       |       |      | f. tons.|
+-------+-------+-------------+-------+-------+------+---------+
+  6    |  36   |   6" B.L.R. |  100  |  5.96 | 1389 |  1337   |
+  7    |  36   |   6"   "    |  100  |  5.96 | 1528 |  1619   |
+  8    |  36   |   8"   "    |  250  |  7.96 | 1213 |  2550   |
+  9    |  36   |   8"   "    |  250  |  7.96 | 1308 |  2966   |
+ 10    |  36   |   8"   "    |  250  |  7.96 | 1399 |  3390   |
+ 11    |  36   |   8"   "    |  250  |  7.96 | 1489 |  3839   |
+ 12    |  36   |  10"   "    |  500  |  9.96 | 1247 |  5386   |
+ 13    |  36   |  10"   "    |  500  |  9.96 | 1315 |  5987   |
+ 14    |  36   |  10"   "    |  500  |  9.96 | 1381 |  6608   |
+ 15    |  36   |  12"   "    |  850  | 11.96 | 1215 |  8699   |
+ 16    |  36   |  12"   "    |  850  | 11.96 | 1269 |  9710   |
+ 17    |  36   |  12"   "    |  850  | 11.96 | 1332 | 10454   |
+ 18    |  36   |  12"   "    |  850  | 11.96 | 1374 | 11124   |
+ 19    |  36   |  12"   "    |  850  | 11.96 | 1425 | 11965   |
+ 20    |  36   |  12"   "    |  850  | 11.96 | 1476 | 12837   |
+-------+-------+-------------+-------+-------+------+---------+
+</pre>
+
+<p>No projectile or fragment of the plate or projectile
+must get wholly through the plate and backing. The
+plate must not break up or give such cracks as to expose
+the backing, previous to the third shot.</p>
+
+<p>The penetration of projectiles of different forms
+into various styles of armor has been very thoroughly
+studied and many attempts have been made to bring
+the subject down to mathematical formulæ. These
+formulæ are based on several suppositions, and agree
+very closely with results obtained in actual experiments,
+but there are so many varying conditions that
+it is extremely doubtful if any formulæ will ever be
+written that will properly express the penetration.</p>
+
+<p>Many different forms have been given to the heads
+of projectiles, as flat, ogival, hemispherical, conoidal,
+parabolic, blunt trifaced, etc.</p>
+
+<p>The flat headed projectile has the shape of a right
+cylinder, and acts like a punch, driving the material of
+the armor plate in front of it. These projectiles are
+especially valuable when firing at oblique armor, for
+they will bite or cut into the armor when striking at
+an angle of thirty degrees.</p>
+
+<p>The ogival head acts more as a wedge, pushing the
+metal aside, and generally will give more penetration
+in thick solid plates than the flat headed projectile.
+The ogival head is usually designed by using a radius
+of two calibers.</p>
+
+<p>The hemispherical, conoidal, parabolic and blunt
+trifaced all give more or less of the wedging effect.
+The blunt trifaced has all the good qualities of the ogival
+of two calibers. It bites at a slightly less angle,
+and the three faces start cracks radiating from the
+point of impact.</p>
+
+<p>Forged steel is the best material for armor-piercing
+projectiles, but many are made of chilled cast iron, on
+account of its great hardness and cheapness.</p>
+
+<p>The best weight for a projectile is found by the formula</p>
+
+<pre>
+        w = d³ (0.45 to 0.5)
+</pre>
+
+<p>w being the weight in pounds, d the diameter in inches
+and 0.45 to 0.5 having been determined by experiment.</p>
+
+<p>With a light projectile we get a flat trajectory, and
+accuracy at short ranges is increased. With a heavy
+projectile the resistance of the air has less effect and
+the projectile is advantageously employed at long ranges.</p>
+
+<p>In the following formulæ, used in calculating the
+penetration of projectiles in rolled iron armor,</p>
+
+<pre>
+  g = the force of gravity.
+  w = the weight of projectile in pounds.
+  d = the diameter of projectile in inches.
+  v = the striking velocity in feet per second.
+  P = the penetration in inches.
+</pre>
+
+<p>Major Noble, R.A., gives</p>
+
+<p><img src="./images/tex2.png" align="middle" alt=
+"P = \sqrt[1.6]{\frac{w \ v^2}{\pi \  g \  d \ 11334.4}}"></p>
+
+<p>U.S. Naval Ordnance Proving Ground uses</p>
+
+<p><img src="./images/tex3.png" align="middle" alt=
+"P = \sqrt[2.035]{\frac{w \ v^2}{\pi \  g \  d \ 3852.8}}"></p>
+
+<p>Col. Maitland gives</p>
+
+<p><img src="./images/tex4.png" align="middle" alt=
+"P = \frac{w \ v^2}{g \  d^2 \ 16654.4}"></p>
+
+<p>Maitland's latest formula, now used in England, is</p>
+
+<p><img src="./images/tex5.png" align="middle" alt=
+"P = \frac{v}{608.3} \sqrt{\frac{w}{d}} - 0.14 \ d"></p>
+
+
+<p>General Froloff, Russian army, gives</p>
+
+<p><img src="./images/tex6.png" align="middle" alt=
+"P = \frac{w \ v}{d^2 \ 576}"></p>
+
+<p>for plates less than two and one-half inches thick, and</p>
+
+<p><img src="./images/tex7.png" align="middle" alt=
+"P = \frac{w \ v}{d^2 \ 400} - 1.5"></p>
+
+<p>for plates more than two and one-half inches thick.</p>
+
+<p>If &theta; be the angle between the path of the projectile
+and the face of the plate, then v in the above formulæ
+becomes v sin &theta;.</p>
+
+<p>When we come to back the plates, their power to
+resist penetration becomes greater, and our formula
+changes. The Gavre formula, given above, is used to
+determine the velocity necessary for a projectile to pass
+entirely through an iron plate and its wood backing.</p>
+
+<p>Compound and steel armor are said to give about
+29 per cent. more resisting power than wrought iron,
+but in one experiment at the proving ground, at Annapolis,
+a compound plate gave over 50 per cent. more
+resisting power than wrought iron.</p>
+
+<p>The Italian government, after most expensive and
+elaborate comparative tests, has decided in favor of
+the Creusot or Schneider all-steel plates, and has
+established a plant for their manufacture at Terni,
+near Rome.</p>
+
+<p>The French use both steel and compound plates;
+the Russians, compound; the Germans, compound;
+the Swedes and Danes use both. Spain has adopted
+and accepted the Creusot plate for its new formidable
+armored vessel, the Pelayo; and China too has recently
+become a purchaser of Creusot plates.</p>
+
+<p>Certain general rules may be laid down for attacking
+armor. If the armor is iron, it is useless to attack with
+projectiles having less than 1,000 feet striking velocity
+for each caliber in thickness of plate. It is unadvisable
+to fire steel or chilled iron filled shells at thick
+armor, unless a normal hit can be made. When perforation
+is to be attempted, steel-forged armor-piercing
+shells, unfilled, should be used. They may be filled if
+the guns are of great power as compared to the armor.
+Steel and compound armor are not likely to be pierced
+by a single blow, but continued hammering may break
+up the plate, and that with comparatively low-powered
+guns.</p>
+
+<p>Wrought iron must be perforated, and hard armor,
+compound or steel, must be broken up. Against wrought
+iron plates the projectile may be made of chilled cast
+iron, but hard armor exacts for its penetration or
+destruction the use of steel, forged and tempered. Against
+unarmored ships, and against unarmored portions of
+ironclads, the value of rapid-firing guns, especially
+those of large caliber, can hardly be overestimated.</p>
+
+<p>The relative value of steel and compound armor is
+much debated, and at present the rivalry is great, but
+the weight of evidence and opinion seems to favor the
+all-steel plate. The hard face of a compound plate is
+supposed to break up the projectile, that is, make the
+projectile expend its energy on itself rather than upon
+the plate, and the backing of wrought iron is, by its
+greater ductility, to prevent the destruction of the
+plate. It seems probable that these two systems will
+approach each other as the development goes on. An
+alloy of nickel and steel is now attracting attention
+and bids fair to give very good results.</p>
+
+<p>The problem to be solved, as far as naval armor is
+concerned, is to get the greatest amount of protection
+with the least possible weight and volume, and this
+reduction of weight and volume must be accomplished,
+in the main, by reducing the thickness of the plates
+by increasing the resisting power of the material. In
+the compound plate great surface hardness is readily
+and safely attained, but it has not yet been definitely
+determined what the proper proportionate thickness
+of iron and steel is.</p>
+
+<p>A considerable thickness of steel is necessary to aid,
+by its stiffness, in preventing the very ductile iron from
+giving back to such an extent as to distort the steel
+face and thus tear or separate the parts of the plate.
+The ductile iron gives a very low resisting power, its
+duty being to hold the steel face up to its work. If
+now we substitute a soft steel plate in the place of the
+ductile iron, we will get greater resisting power, but
+our compound plate then becomes virtually an all-steel
+one, only differing in process of manufacture. The
+greatest faults of the compound plate are the imperfect
+welding of the parts and the lack of solidity of the
+iron. When fired at, the surface has a tendency to
+chip.</p>
+
+<p>In the all-steel plate we have the greatest resisting
+power throughout, but there are manufacturing difficulties,
+and surface hardness equal to that of the compound
+plate has not been obtained. The manufacturing
+difficulties are being gradually overcome, and
+artillerists are in high hopes that the requisite surface
+hardness will soon be obtained.</p>
+
+<p>The following may be stated as well proved:</p>
+
+<p class="ind">1. That steel armor promises to replace both iron and compound.<br />
+<br />
+2. That projectiles designed for the piercing of hard
+armor must be made of steel.<br />
+<br />
+3. That the larger the plate, the better it is able
+to absorb the energy of impact without injury to itself.<br />
+<br />
+4. That the backing must be as rigid as possible.<br />
+</p>
+<hr />
+
+[FROM ENGINEERING.]
+
+<a name="ce-1"></a><h2>THE COMPRESSED AIR SYSTEM OF PARIS.</h2>
+
+<p>The demand for compressed air as a motive power is
+constantly increasing in Paris; the company, according
+to its official reports, is financially prosperous, and
+it seems difficult to understand how it should continue
+as an actively going concern, unless it at all events
+paid its way. The central station of St. Fargeau,
+originally started on modest lines, for maintaining a
+uniform time by pneumatic pressure throughout Paris,
+has grown rapidly to very large proportions, though it
+has never been able to supply the demand made on it
+for power; and at the present time a second and still
+larger station is being constructed in another part of
+Paris. We confess that we do not understand why such
+large sums of money should continue to be spent if the
+
+enterprise is not commercially a sound one, nor how men
+of such eminence in the scientific world as Professor
+Riedler should, without hesitation, risk their reputation
+on the correctness of the system, if it were the idle
+dream of an enthusiast, as many persons&mdash;chiefly those
+interested in electric transmission&mdash;have declared it
+to be.</p>
+
+<p class="ctr"><a href="./images/9-fig1.png">
+<img src="images/9-fig1-th.jpg" alt="Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION" title=""></a><br clear="all" />Fig. 1.&mdash;MAP OF PARIS WITH ST. FARGEAU STATION</p>
+
+<p>In describing the developments that have taken
+place during the last two years, we shall confine ourselves
+entirely to the details of a report recently made
+on the subject by Professor Riedler. As soon as it
+became evident that a very largely increased installation
+was necessary, it was determined that the new central
+station should be as free as possible from the defects
+of the first one. These defects, which were the natural
+results of the somewhat hasty development of an
+experimental system, were of several kinds. In the first
+place, so large a growth had not been contemplated,
+
+and the extensions were made more or less piecemeal,
+instead of being on a regular plan; the location of the
+central station itself was very unfavorable, both as regards
+the facilities for obtaining coal and other supplies;
+the cost of water was excessive, and the amount
+available, inadequate.</p>
+
+<p>This evil was partly remedied by elaborate arrangements
+for cooling the injection water so that it could
+be repeatedly used, a device costly and ineffective,
+and resulting in extravagant working, to say nothing
+of the high charges made by the Paris company for
+supplying water. To these drawbacks had to be added
+others of an even more serious character. The engines
+first laid down were not economical, and the compressors
+employed gave but a very inferior result; with
+each extension of the plant, the efficiency of both engines
+and compressors was increased, the most satisfactory,
+we believe, having been those supplied by the
+
+Societe Cockerill, and one of which was exhibited at the
+Paris exhibition in 1889. Still it was clearly recognized
+that much better results were possible, results which
+Professor Riedler claims have been attained and which
+will be embodied in the new installation now in progress.</p>
+
+<p>This central station is located on the left bank of the
+Seine, close to the fortifications, opposite Vincennes
+and not far from the terminal stations of the Orleans
+and the Paris, Lyons, and Mediterranean Railways;
+the plan, Fig. 1, shows the position. The works are
+separated from the river by the quay, over which a
+bridge will be constructed for the transfer of coal from
+the landing stages belonging to the company, into the
+works; as will be readily seen from the plan, it would
+be quite easy to run junction lines to the two adjacent
+railways, but with all the advantages given by water
+carriage, it was considered unnecessary to incur the expense.
+The river also affords a constant and unlimited
+water supply, so that none of the difficulties existing
+at St. Fargeau Station in imperfect condensation and
+cooling will be met with.</p>
+
+<p>The new installation, called the Central Station of
+the Quai de la Gare, is laid out on a very large scale,
+the total generating energy provided for being no less
+than 24,000 horse power; of this it is intended that
+8,000 horse power will be in operation this year, and an
+extension of 10,000 horsepower in 1892; the power now
+in course of completion comprises four engines of 2,000
+horse power each. Four batteries of boilers will provide
+steam for these engines. Figs. 2, 3, and 4 show the first
+section of the installation now in progress; the four
+groups of engines (three-cylinder condensing) are shown
+at 1, 2, 3, and 4; the four groups of boilers ranged behind
+them at F, F; the feed water heaters belonging to
+each group at V V.</p>
+
+<p class="ctr"><a href="./images/9-fig234.png">
+<img src="images/9-fig234-th.jpg" alt="COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS. (FIG. 2,3,4)" title="">
+</a><br clear="all" />COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS. (FIG. 2,3,4)</p>
+
+<p>The end of the building abuts against the Seine, and
+the position of the water conduits for inlet and discharge
+are indicated at C and A respectively. The installation,
+when completed, will include very extensive
+arrangements for transporting and storing coal, and
+the interior of the boiler houses will be furnished with
+an overhead system of rails and carriers for handling
+the coal automatically, as far as possible. All the
+principal mains and steam pipes are made in duplicate,
+not only for greater security, but in order that
+each set of engines and boilers may be connected interchangeably
+without delay. The Seine supplies an
+ample quantity of water, but not in a condition either
+for feeding the boilers, for condensation, or for the air
+compressors.</p>
+
+<p>Special provisions have therefore to be made to
+filter the water efficiently before it is used. For this
+purpose the water is led to a group of four filters (see
+L, Fig. 4); from them it passes into the tanks, JJ, and
+is pumped into the heaters. The filters can be rapidly
+and automatically cleaned by reversing the flow of
+water through them. Figs. 5 and 6 show the general
+form of the type of engine adopted, as well as the engine
+house, some of the mains, etc. They are vertical
+triple-expansion engines, and are being constructed by
+MM. Schneider et Cie, of Creusot, with a guarantee of
+coal consumption not to exceed 1.54 lb. per horse power
+per hour, with a penalty of 2,000 francs for every 100
+grammes in excess of this limit. It is evident that with
+this restricted fuel consumption, a large margin for
+economy will exist at the new works, as compared with
+the St. Fargeau station, where the best engines cannot
+show anything like this result, while some of the earlier
+ones are distinctly extravagant, and the whole installation
+is handicapped with imperfect means of condensation.</p>
+
+<p class="ctr"><a href="./images/9-fig56.png">
+<img src="images/9-fig56-th.jpg" alt="THE NEW COMPRESSED AIR STATION AT
+PARIS. (FIG. 5, 6)" title=""></a><br clear="all" />THE NEW COMPRESSED AIR STATION AT
+PARIS. (FIG. 5, 6)</p>
+
+<p>Moreover, according to Professor Riedler, the consumption
+of steam by the new Schneider engines will
+be only 5.3 kilos. per horse power and per hour as compared
+with some of the large engines requiring 9 kilos.,
+and the Cockerill engines&mdash;using 8 kilos. per hour, not
+to speak of the older motors that are very extravagant
+in the use of steam. The St. Fargeau station is worked
+under a further disadvantage. The constantly increasing
+demand from subscribers taxes the resources of
+the station to their fullest extent, so that practically
+there is no reserve power.</p>
+
+<p>In the new installation the work will be equally constant,
+but care will be taken always to have a sufficient
+reserve. Electric lighting will form a considerable part
+of the duty to be done from this station, and in all
+cases it is intended to work with accumulators, so that
+the resistance to be overcome by the engines, so far as
+this part of the duty is concerned, will be well known
+and uniform. The engineers of the Compressed Air Co.,
+of Paris, have during the last five years acquired an
+experience which could only be attained at a high
+price and at the expense of a certain amount of failure;
+this period, it is claimed, is now passed, and in the
+new installation it is possible to put into practice all
+the valuable lessons learned at St. Fargeau, to say
+nothing of the more favorable natural conditions under
+which the extension is being started and the improvements
+in the compression of the air made by Mr. Popp
+and Professor Riedler, and to which we shall refer
+later.</p>
+
+<p>Chiefly in consequence of the high value of the
+ground, vertical engines were adopted at the new
+station; the proximity to the river made the foundations
+somewhat costly, and the risk of occasional floods
+rendered it desirable to set the level of the engine bedplates
+20 inches above the floor of the building; the
+foundations of the engines are continuous, but are quite
+independent of the building. There are three compressing
+cylinders in each set of engines, one being
+above each steam cylinder. Two of these are employed
+to compress the air to about 30 lb. per square inch,
+after which it passes into a receiver and is cooled; it is
+then admitted into the third or final compressing cylinder
+and raised to the working pressure at which it flows
+into the mains. In the illustrations, h, m, and b are
+the high, intermediate, and low pressure cylinders of
+one set of engines; as will be seen, each cylinder is on a
+separate frame connected by girders; directly above
+the cylinders are the two low and the one high pressure
+air cylinders, b¹, m¹, and h¹ respectively. The former
+deliver the air compressed to the first stage into the
+receiver, T¹ (see Fig. 5), whence it passes into the third
+compression cylinder, and thence by a main into the
+cylinders, R R, which are in direct communication with
+the delivery mains; these mains terminate in the subway,
+T. The water for condensation is brought into
+the engine house by the channel, C, and the condenser
+pumps, a, draw direct from this supply; the discharge
+main back to the river is shown at A. The relative
+positions of the engine and boiler houses are indicated
+in Figs. 2 to 5, where F shows the end of one group of
+boilers; the air supply for the compressors is led from
+the central raised portion, S, of the roof.</p>
+
+<p>Professor Riedler's first experiments in improving
+the efficiency of air compressors were made with one
+of the Cockerill compressors in use at the St. Fargeau
+Station, and considerable difficulty attended this work,
+because the machinery was necessarily kept almost in
+constant operation. These compressors were designed
+by MM. Dubois and Francois, of Seraing. Two of their
+leading features were the delivery of the compressed
+air at as low a temperature as possible, and with a relatively
+high piston speed of about 400 ft. a minute.
+The former object is attained by the injection of a
+very fine water spray at each end of the air cylinder,
+and its rapid removal with each stroke; the free as
+well as the compressed air flows through the same
+passages, one at each end of the cylinder; the inlet
+valves being placed at the side of these passages, and
+the outlet or compressed air valves at the top, the
+compressed air, entering a chamber above the cylinder,
+common to both valves, and passing thence to the reservoir.
+The compressed air valves, which are seven in.
+in diameter, are brought back sharply to their seats at
+each stroke, by a small piston operated by compressed
+air flowing through a by-pass from the chamber. The
+illustrations published by us on page 686 of our forty-seventh
+volume show the construction of these compressors.
+The engravings on page 683 of the same volume
+illustrate the compressors used in a somewhat older
+part of the installation; they were made by M. Blanchod,
+of Vevey, and a passing reference may be made
+to them. The air is admitted through valves in the
+cylinder, and is forced out through spring-loaded
+valves; water is admitted into the cylinder to cool the
+air.</p>
+
+<img src="images/10-fig7.png" align="right" alt="Fig. 7" title="">
+
+<p>Fig. 7 indicates the modification made by Professor
+Riedler in one of the Cockerill compressors: a receiver,
+A, was placed under the two compressing cylinders, B
+and C. The first stage is completed in the large cylinder,
+B, the air being compressed to about 30 lb. per
+square inch; from this it is discharged into the receiver,
+A, through the pipe, B¹, where it meets with a
+
+spray injection that cools it to the temperature of the
+water. The final stage is then effected in the smaller
+cylinder, C, which, drawing the air from the receiver
+through the pipe, C¹, compresses it to about 90 lb. and
+delivers it through the pipe, d, to the mains. We hope
+shortly to publish drawings of this compressor in its
+final form; in its elementary stage Professor Riedler
+claims to have obtained some very remarkable results.
+He says that the waste spaces in his modification were
+much smaller than in the Cockerill compressor, while the
+efficiency of the apparatus was largely increased. The
+actual engine duty per horse power and per hour was
+raised, as a maximum, to 384 cubic feet of air at atmospheric
+pressure, and compressed to 90 lb. per square
+inch, a marked increase on the duty of the compressors
+in use at the St. Fargeau station. The Cockerill compressors
+experimented on at the same time showed a
+maximum duty of 306 cubic feet of air. A considerable
+advantage is claimed in drawing clean and cool air from
+the outside of the building, and beyond the main feature
+of carrying out the compression in two stages, Mr.
+Riedler appears to have shown great skill in introducing
+several minor alterations and improvements in the
+plant.</p>
+
+<p><a href="images/10-fig8910.png">
+<img src="images/10-fig8910-th.jpg" align="right" alt="EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig. 8, 9, 10)" title="">
+</a>
+Figs. 8, 9 and 10 are diagrams showing the comparative
+efficiency of the three types of compressors at St.
+Fargeau&mdash;Fig. 10 being a diagram of the Riedler
+compressor&mdash;and indicate the gain derived from the
+intermediate cooling. The loss is shown to be only 12 per
+cent., as compared with a loss of 43 per cent. in a large
+part of the plant, and of 105 per cent. in the earlier
+compressors of the St. Gothard type. The table
+given herewith contains a summary of trials made
+by Professor Gutermuth, and are intended to show
+the comparative results of an extended trial with three
+kinds of compressors at St. Fargeau.</p>
+<br clear="all" />
+
+<pre>
+
+  PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
+
+--------------+-------+--------+------+-------+--------+--------+----------+
+              |       |        |      |       |        |        |          |
+              |Revolu-| Horse- |      |Amount |Quantity| Cubic  |          |
+Compressors.  | tions | Power  |Effic-|of Air | of Air |Feet of |Final Air |
+              |of Eng-|Absorbed|iency.|Passing| Passing|Air per |Pressure. |
+              |ine per|   by   |      |through| through| Horse- |          |
+              |Minute.|Compres-|      | Inlet | Valves | Power  |          |
+              |       | sors.  |      | Valves| per    | and per|          |
+              |       |        |      | each  | Hour.  |  Hour. |          |
+              |       |        |      |Revolu-|        |        |          |
+              |       |        |      | tion. |        |        |          |
+--------------+-------+--------+------+-------+--------+--------+----------+
+              |       |        |      | cubic |  cubic |        |lb. per   |
+1.            |       |        |      | feet  |  feet  |        |sq. in.   |
+<i>Sturgeon</i>      |       |        |      |       |        |        |          |
+<i>Compressor</i>    |  37   |   302  | .87  | 41.67 |  91,507| 261.3  | 90       |
+Diameter of   |  37   |   258  | .87  | 38.13 |  84,650| 276.1  | 90       |
+cylinder,     |       |        |      |       |        |        |          |
+23.62 in.     |       |        |      |       |        |        |          |
+and 21.66 in.;|       |        |      |       |        |        |          |
+stroke,       |       |        |      |       |        |        |          |
+48.63 in.     |       |        |      |       |        |        |          |
+              |       |        |      |       |        |        |          |
+2.            |       |        |      |       |        |        |          |
+<i>Cockerill</i>     | 40    |   337  | .83  | 46.61 | 111,864| 281.83 | 90       |
+<i>Compressor.</i>   | 45    |   353  | .83  | 46.61 | 125,844| 302.66 | 90       |
+Diameter of   | 40    |   342  | .88  | 49.43 | 118,632| 296.65 | 90       |
+cylinder,     | 46    |   377  | .85  | 48.02 | 132,534| 298.77 | 90       |
+25.98 in.;    | 38.67 |   324  | .89  | 50.14 | 116,434| 306.19 | 90       |
+stroke,       | 38.5  |   337  | .89  | 50.14 | 115,818| 294.18 | 90       |
+47.24 in.     | 38.6  |   329  | .91  | 50.84 | 117,740| 305.13 | 90       |
+              |       |        |      |       |        |        |          |
+              |       |        |      |       |        |        |          |
+3.            |       |        |      |       |        |        |          |
+<i>Riedler</i>       | 52    |   615  | .985 | 77.34 | 241,300| 353.50 | 90       |
+<i>Compressor.</i>   | 60    |   709  | .985 | 76.98 | 277,128| 353.50 | 90       |
+Diameter of   | 38    |   422  | .985 | 77.34 | 176,330| 376.12 | 90       |
+low-pressure  | 39    |   424  | .985 | 77.34 | 181,030| 384.60 | 90       |
+cylinder,     |       |        |      |       |        |        |          |
+42.91 in.;    |       |        |      |       |        |        |          |
+diameter of   |       |        |      |       |        |        |          |
+high-pressure |       |        |      |       |        |        |          |
+cylinder,     |       |        |      |       |        |        |          |
+26.38 in.;    |       |        |      |       |        |        |          |
+stroke,       |       |        |      |       |        |        |          |
+47.24 in.     |       |        |      |       |        |        |          |
+--------------+-------+--------+------+-------+--------+--------+----------+
+</pre>
+
+<p>The results thus obtained were so satisfactory that
+the designs were prepared for the great compressors to
+be operated at the new central station on the Quai de
+la Gare by the 2,000 horse power engines.</p>
+
+<p>The transmission of the compressed air through the
+mains is unavoidably attended with a certain percentage
+of loss, which, of course, increases with the length
+of the transmission, the presence of leakage at the
+joints, etc. Professor Riedler has devoted considerable
+time to the investigation of this source of waste,
+and we shall presently refer to the results he has
+recorded; in the first place, however, we propose to
+consider what he has to say on the subject of utilizing the
+air at the points of delivery, and the means employed
+for obtaining a relatively high efficiency of the motor.</p>
+
+<p>In the earliest stages of the Popp system in Paris it
+was recognized that no good results could be obtained
+if the air were allowed to expand direct into the motor;
+not only did the formation of ice due to the expansion
+of the air rapidly accumulate and choke the exhaust,
+but the percentage of useful work obtained,
+compared with that put into the air at the central station,
+was so small as to render commercial results
+hopeless. The practice of heating the air before admitting
+it to the motor is quite old, but until a few years
+ago it never seems to have been properly carried out;
+in several mining installations where this motive power
+had been long used, more or less imperfect attempts
+had been made to heat the air; in one instance only,
+recorded by Professor Riedler, was an efficient means
+employed. In this case a spray of boiling water was
+injected into the cylinder and mixed with the air at
+each stroke, with the result that a very marked economy
+was obtained.</p>
+
+<p>After a number of experiments, Mr. Popp arrived at
+the conclusion that the simplest mode of heating, if
+not the most efficient, was at all events the most suitable,
+as it was a matter of the first importance that subscribers
+should not be troubled with the charge of any
+apparatus involving complication or careful management;
+he therefore adopted a simple form of cast iron
+
+stove lined with fireclay, heated either by a gas jet or
+by a small coke fire. It was found that this apparatus,
+crude as it was, answered the desired purpose,
+until some better arrangement was perfected, and the
+type was accordingly adopted throughout the whole
+system. It was quite recognized that this method still
+left much to be desired, and the economy resulting
+from the use of an improved form was very marked.</p>
+
+<p>From a large number of trials very carefully carried
+out by Professor Gutermuth, it was found that
+more than 70 per cent. of the total number of calories
+in the fuel employed was absorbed by the air and
+transformed into useful work. Whether gas or coal
+be employed as the fuel, the amount required is so
+small as to be scarcely worth consideration; according
+to the experiments carried out, it does not exceed 0.09
+kilo. per horse power and per hour, but it is scarcely
+to be expected that in regular practice this quantity
+is not largely exceeded. Professor Weyrauch has also
+carefully investigated this part of the subject and fully
+confirms, if he, indeed, does not go beyond Professor
+Gutermuth. He claims that the efficiency of fuel consumed
+in this way is six times greater than when burnt
+under a boiler to generate steam. He goes so far as to
+assert that with a good method of heating the air, not
+only can all the losses due to the production and
+the transmission of the compressed air be made good,
+but also that it will actually contain more useful energy
+at the motor than was expended at the central
+station in compressing it.</p>
+
+<p>According to Professor Riedler, from 15 to 20 per
+cent. above the power at the central station can be
+obtained by means at the disposal of the power users,
+and it has been shown by experiment that by heating
+the air to 250 deg. Cent. an increased efficiency of 30
+per cent. can be obtained. Better results than those
+heretofore obtained may, therefore, be confidently expected
+with a more perfect and economical application
+of the fuel in heating the air, and a better means of
+regulation in admitting it to the motors. In his report
+Professor Riedler indicates a method by the use of
+which he considers considerable advantages may be
+secured. This is the heating the air in two stages instead
+of at one operation, and passing it through two
+motors, to the first of which the air is admitted heated
+only to a moderate extent; the exhaust from this motor
+then passes into a second heater and thence into
+the second motor. A series of experiments with this
+arrangement were recently carried out.</p>
+
+
+<p>The consumption of air per brake horse power was
+reduced from 812 cubic feet per hour, a favorable duty
+in the single motor, to 720, and in the best result to
+646 cubic feet with the two motors and double heaters.
+It should be added that these trials were carried out
+with steam engines but ill adapted for the purpose.
+It is to be regretted that the experiments of Professor
+Riedler could not have been conducted with more perfect
+appliances, but it must be borne in mind that the
+utilization of compressed air, especially as regards the
+motors, is still in a very imperfect stage, and that a
+great deal remains to be done before the maximum
+power available at the motor can be obtained. Investigations
+in this direction for a considerable time to
+come must be directed, therefore, toward improving
+the design and construction of the motors and the
+treatment of the air at the point of delivery into the
+engine.</p>
+
+<p>A large number of motors in use among the subscribers
+to the Compressed Air Company, of Paris, are rotary
+engines developing one horse power and less, and
+these in the early times of the industry were extravagant
+in their consumption, to a very high degree. To
+some extent this condition of things has been improved,
+chiefly by the addition of better regulating valves
+to control the air admission.</p>
+
+<p>As altered, the two horse power rotary motors, when
+employed as cold air engines, a method often desired
+in special industries, consume 1,059 cubic feet per hour
+and per indicated horse power; with a moderate degree
+of heating, say to 50 deg. Cent., this consumption
+falls to 847 cubic feet. The efficiency of this type of
+rotary motors with air heated to 50 deg. may now be
+assumed at 43 per cent., not a very economical result,
+it is true, and one that may be largely improved, yet it
+is evident that with such an efficiency the use of small
+motors in many industries becomes possible, while in
+cases where it is necessary to have a constant supply
+of cold air, economy ceases to be a matter of the first
+importance.</p>
+
+<p>Some useful results were obtained with compressed
+air used in crank engines; it is to be regretted that with
+this, also, apologies have to be made for the imperfect
+design and construction; they were old steam engines,
+some of those of two horse power losing from 25 to 30
+per cent. by their own friction; some of the others tried,
+however, were far better, a newer type losing only from
+8 to 10 per cent., while the 80 horse power referred to
+below showed an efficiency of 91 per cent. From these
+trials Prof. Riedler deduces&mdash;assuming 85 per cent. efficiency&mdash;a
+consumption of 611, 752, and 720 cubic feet
+per brake horse power. It is very evident from the
+foregoing that the Compressed Air Company, of Paris,
+will never do itself justice until as much thought and
+care has been devoted to the economical use of the motive
+power as has been expended in the means of producing
+it, and Professor Riedler's recent investigations
+should be especially useful in this respect. The question
+has indeed attracted the attention of more than
+one manufacturer, and reference is made to a particular
+type of small rotary motors which are being constructed
+by MM. Riedinger &amp; Co., and which is stated
+have given very excellent results. These engines were
+specially used for working sewing machines and developed
+on the brake an efficiency of 34.07 and 51.63
+foot pounds per second. Trials were made with a half
+horse power variable expansion Riedinger engine.</p>
+
+<pre>
+     TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
+ ______________________________________________________________
+                                               |       |
+  Number of trials.                            |   I.  |   II.
+ ______________________________________________|_______|_______
+                                               |       |
+ Initial air pressure.     lb. per square inch |    86 | 71.8
+      "      temperature.           deg. Cent. |   +12 |  +170
+ Ft. pounds per second  measured on the brake. | 51.63 | 34.07
+ Revolutions per minute.                       |   384 |  300
+ Consumption of air for one horse power per    |       |
+    hour.                                      | 1,377 |  988
+ ______________________________________________|_______|_______
+
+
+     TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
+ _____________________________________________________________________
+                                           |      |      |      |
+  Number of trials.                        |  I.  |  II. | III. |  IV.
+ __________________________________________|______|______|______|_____
+                                           |      |      |      |
+ Initial pressure of air.  lb. per sq. in. |   54 | 69.7 |   85 | 71.8
+      "  temperature of air.    deg. Cent. |  170 |  180 |  198 |    8
+ Final        "        "            "      |   25 |   20 |  ... |   25
+ Revolutions per minute.                   |  335 |  350 |  310 |  243
+ Foot pounds per second measured on        |      |      |      |
+    brake.                                 |  271 |  477 |  376 |  316
+ Consumption of air per horse power        |      |      |      |
+    and per hour.                          |  883 |  791 |  900 |1,148
+ __________________________________________|______|______|______|_____
+
+
+    TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
+ ______________________________________________________________
+                  |      |      |             |
+                  | Re-  | In-  |             | Consumption of
+                  | vo-  | di-  | Temperature |  air per horse
+                  | lu-  | ca-  |    of air.  |  power and per
+                  |tions | ted  |             |      hour.
+                  |      |      |_____________|________________
+                  | per  |horse |      |      |       |
+    Motor.        |      |      |Admis-| Ex-  |Nominal| Brake
+                  | min- |power.| sion.|haust.| horse | horse
+                  | ute. |      |      |      | power.| power.
+ _________________|______|______|______|______|_______|________
+                  |      |      |deg. C|deg. C|       |
+ Nominal 80 horse | 54.3 | 72.3 |  129 |  21  |  469  |  517
+ power single cy- | 54.3 | 72.3 |  152 |  29  |  437  |  475
+ linder Farcot    | 54.0 | 72.3 |  160 |  35  |  424  |  465
+ engine.          | 40   | 65.0 |  170 |  49  |  438  |  477
+ _________________|______|______|______|______|_______|______________
+</pre>
+
+<p>These motors, it may be assumed, represent the best
+practice that has been obtained up to the present time
+in the construction of compressed air motors; with the
+smallest of them, indicating about one-tenth of a horse
+power, the consumption of air, when admitted cold,
+was 1377 cubic feet and 988 cubic feet when the air was
+heated before admission. The half horse power engine
+consumed 1148 cubic feet of cold air, and of heated air
+791 cubic feet per horse power and per hour. It
+should be mentioned that these, the most valuable and
+suggestive of all the trials carried out by Professor
+Riedler, were conducted with the greatest care, two
+distinct modes of measuring the air supplied being
+followed on two occasions for each test; it may therefore
+be considered that the results given are absolutely
+correct. The trials were made with an old single cylinder
+
+Farcot engine, nominally of 80 horse power, but indicating
+over 72.3. With this engine the consumption of
+air varied from 465 to 517 cubic feet, the larger consumption
+being due to the lower temperature (129 deg.
+Cent.) to which the air was raised before admission; in
+the most economical result the temperature was 160
+deg. Cent. The volumes of air referred to are, of
+course, in all cases taken at atmospheric pressure.</p>
+
+<p>Among the important losses that have to be reckoned
+with in every system of distributing motive power
+from a central station&mdash;whether by steam or by electricity,
+water, or compressed air&mdash;losses must occur in
+the mains by which the power generated is transferred
+from the point of production to that of consumption.
+In the case we are now considering very careful tests
+were conducted in 1889 by Professor Kennedy, to whose
+report we have already referred. Since that time important
+changes have been made by the Compressed
+Air Company, at Paris, in the details of distribution,
+and on this account the later investigations of Professor
+Riedler on the losses due to this cause are of special
+interest.</p>
+
+<p>Before its admission into the mains a certain loss occurs
+at the St. Fargeau station, in the large reservoirs
+to which the air is delivered from the compressors. This
+question of preliminary storage was one that received
+considerable attention when the designs of the new station
+on the Quai de la Gare were being considered. It was
+intended to construct very large receivers in the basement
+of the station, and the foundations for these were
+even commenced. It was decided, however, that for
+the 10,000 horse power which is to form the first section
+of the new station, and for which the complete
+system of mains has already been laid down, storage
+reservoirs would be unnecessary, and a saving both in
+first cost and subsequent loss of air would be effected.
+The length of mains of 19.69 in. diameter is so considerable
+that they will contain at all times a sufficient
+reserve of air to prevent any irregularities in pressure
+at the motors.</p>
+
+<p>With reference to these mains it may be mentioned
+that, unlike the 11.81 in. conductors of the St. Fargeau
+system, of which 17 kilometers are laid in the Paris
+subways, the new mains are entirely laid in the streets,
+it having been found impossible to make room for these
+large pipes in the subways already crowded with telegraph
+and telephone wires, water mains, etc.</p>
+
+<p>Professor Riedler investigated the two causes of loss
+in the mains&mdash;leakage and resistance. It was superficially
+evident that the mains of the old system were
+so well laid, and the joints so well designed, that the loss
+from leakage was never a serious one. In order, however,
+to ascertain the amount accurately, a series of careful
+experiments were carried out by Professor Gutermuth
+with the 11.81 in. mains of the St. Fargeau
+system.</p>
+
+<p>These trials refer to the mains running from the St.</p>
+
+<pre>
+     EXPERIMENTS ON LEAKAGE IN MAINS.
+
+---------------------------------------------------------------------
+| |                 |         |               |             | L P A |
+| |                 |         | Air Pressure  |   Loss of   | o e i |
+| |                 |         |  in Mains.    |  Pressure.  | s r r |
+| |                 |         |---------------|-------------| s     |
+| |                 |         |       |       |      |      |   C D |
+| |System of Mains  | Length. |       |       |      |      | o e e |
+|N|    Tried.       |         |  At   |  At   |      |      | f n l |
+|u|                 |         |Begin- | End   |During| Per  |   t i |
+|m|                 |         |ning of|  of   |Trials|Hour. | A . v |
+|b|                 |         |Trials.|Trials.|      |      | i   e |
+|e|                 |         |       |       |      |      | r o r |
+|r|                 |         |       |       |      |      |   f e |
+| |                 |         |       |       |      |      |     d |
+--+-----------------+---------+-------+-------+------+------+-------|
+| |                 | yards.  | atm.  |  atm. |      |      |       |
+|1|Southern reseau  |         |       |       |      |      |       |
+| | to Place de la  |         |       |       |      |      |       |
+| | Concorde.       |  9,980  | 6.5   |  6.0  | 0.5  | 1.5  |  3    |
+|2| Total reseau    | 18,500  | 6.9   |  5.9  | 1.0  | 1.5  |  6.3  |
+|3|To Place de      |         |       |       |      |      |       |
+| | la Concorde     |  9,980  | 7.0   |  6.43 | 0.57 | 0.75 |  2.16 |
+|4|Total reseau     | 18,500  | 6.7   |  5.28 | 0.88 | 1.32 |  5.5  |
+|5|Northern reseau  |         |       |       |      |      |       |
+| | to Rue de Belle-|         |       |       |      |      |       |
+| | ville.          |  1,530  | 6.0   |  5.0  | 1.0  | 0.6  |  2.3  |
+|6|To the Rue des   |         |       |       |      |      |       |
+| | Pyrenees.       |    600  | 6.1   |  3.7  | 2.4  | 0.56 |  2.2  |
+---------------------------------------------------------------------
+</pre>
+
+<p>Fargeau station to the Place de la Concorde, a length
+of 9.142 kilometers; to the whole system of mains, 16.5
+kilometers; to the northern mains running from St.
+Fargeau to the Rue de Belleville, 1.4 kilometers; and
+from St. Fargeau to the Rue des Pyrenees, 6.5 kilometers.
+It will be seen from the figures given in the table
+that the actual loss is small, and it is stated that
+this is due chiefly to the elastic joint employed throughout
+the system, excepting in the Rue de Belleville,
+where rigid couplings are used, and continual trouble
+is experienced from loss by leakage. In all cases the
+losses given are the maximum, which only occur under
+the most unfavorable conditions.</p>
+
+<p>It was found, during the first, second, and fourth
+tests, that considerable leakage occurred between the
+St. Fargeau central station and the Rue de Belleville.
+During the trials two and four, an uncertain amount
+of loss occurred from the consumption of air required
+to work the pneumatic clocks, and also motors in the
+circuit, that could not be stopped. The tests two and
+four include all losses in the service pipes, as well as
+the mains.</p>
+
+<p>The production of compressed air at the central station
+is assumed at 30,000 cubic feet per hour (atmospheric
+pressure), and in all cases the loss in the
+mains is taken as a percentage of the total production.</p>
+
+<p>The losses due to resistance in the mains were also
+examined with great care, over independent sections,
+as well as through the complete <i>réseau</i>. During the
+early part of these trials, an unusual and excessive loss
+was recorded, the cause of which could not be at first
+ascertained. At intervals along these mains are placed
+a number of water reservoirs which receive the water
+injected into the mains; in addition to these the direct
+flow of the air is interrupted by numerous siphons, the
+stop valves to branches, etc. Investigation showed
+that the presence of these reservoirs created considerable
+resistance on account of an increased and subsequently
+reduced section. The exact loss from this
+cause was, therefore, carefully measured, as well as the
+losses existing in the mains not so interrupted. The
+results show that the loss by expansion at one reservoir,
+when the speed of the air flow was 23 ft. per
+second, was equal to 0.15 atmosphere; with a speed
+of 29 ft. 6 in. per second, it amounted to 0.2 atmosphere.</p>
+
+<p>Therefore, the presence of five such reservoirs would
+cause a loss in pressure equal to one atmosphere. This
+very undesirable arrangement is not repeated in the
+new system, the sumphs being connected in such a way
+as not to modify the section of the tube, nor consequently
+the pressure of the air. The presence of the
+siphons and stop valves did not seem to affect the
+pressure to any measurable extent. The following
+table contains a list of the more important mains tested,
+and it may be mentioned that the resistance, due
+to the reservoirs, was at first partially included. The
+trials were carried out while the mains were not being
+drawn upon by subscribers. </p>
+
+<pre>
+-----------------------------------------------------------------------
+                                                   |            |
+Section of Mains Tested.                           |  Length.   |No. of
+                                                   |            |Tests.
+                                                   |            |
+---------------------------------------------------+------------+------
+                                                   |  yards.    |
+From the central station to the end of reseau and  |            |
+  back to central station by return circuit        |  18,100    |   7
+From the central station to the Rue Fontaine au    |\ 14,600    |/  3
+  Roi                                              |/  9,900    |\  4
+From the central station to the Rue de la          |            |
+  Charonne                                         |   9,490    |   5
+From the Rue de la Charonne to Fontaine au         |            |
+  Roi                                              |   4,770    |   3
+From the central station to the Avenue de la       |            |
+  Republique                                       |   1,860    |   8
+Various trials on different lengths of mains       |770 to 8,000|  11
+-----------------------------------------------------------------------
+</pre>
+
+<p>Over the whole system of 16.5 kilometers, which was
+also tested when no air was being taken off, there were
+four reservoirs of considerable size, and which offered
+a large resistance with a corresponding loss of pressure;
+on the line there were also 23 siphons and 42 stop
+valves.</p>
+
+<p>These trials were repeated several times to secure
+accuracy, and the speed of the air was brought to 49
+ft. a second. The results obtained in one of these trials
+may be taken as an example. The main between the
+Rue St. Fargeau and the Fontaine au Roi, on which
+there are no collecting reservoirs, but three siphons
+and eight stop valves, gave, with an average speed of
+21 ft. 3 in., a loss in pressure of 0.05 atmosphere for each
+kilometer of main.</p>
+
+<p>From these experiments it would appear that, assuming
+a speed of 21 ft. per second, a loss in pressure
+of one atmosphere would correspond to a distance of
+20 kilometers; that is to say, a central station could extend
+its mains on all sides with a radius of 20 kilometers,
+and the motors at the ends of the lines would receive
+the air at a pressure 15 lb. less than at the central
+station. Professor Riedler states that as an actually
+measured result, the velocity of the air through the
+mains of the St. Fargeau system is 19 ft. 8 in. per
+second, and that the loss in pressure per kilometer is
+0.07 atmosphere. From this it follows that including
+the resistances due to the four reservoirs, and other obstructions
+actually existing, an allowance of one atmosphere
+loss on a 14 kilometer radius is ample. By
+increasing the initial pressure of the air, much better
+results can be obtained, and future attention in practice
+should be devoted to this point. The amount of
+work required to compress air does not increase in the
+same ratio as the pressure, and for this reason considerable
+economy can be effected at the first stage,
+and the loss in the mains will be reduced.</p>
+
+<p>Passing to another point of the same subject, Professor
+Riedler considers the best dimensions that should
+be given to the mains. Resistance decreases with an
+increase in the diameter of these and in direct ratio to
+their diameter; for this reason&mdash;still assuming a pressure
+corresponding to a velocity of 20 ft. per second&mdash;with
+a fall of one atmosphere, a length of 40 kilometers
+could be succesfully worked.</p>
+
+<p>The mains of the new <i>réseau</i> for the Quai de la Gare
+station are 19.69 in. in diameter; they are built up of
+steel plates riveted, and this Professor Riedler considers
+to have been a serious error on account of the
+extra resistance offered by the large number of rivet
+heads.</p>
+
+<p>The following may be taken as a brief summary
+of Professor Riedler's conclusions: Recent improvements
+in central station practice have resulted in an
+increased efficiency of about 30 per cent. in the compressors,
+but this benefit can only be realized when the
+new station is in operation. That the small and very
+imperfect air engines in use on the system give an
+efficiency of 50 per cent., while with ordinary
+steam engines driven by air an efficiency of 80 per cent.
+can be reached with a very small expenditure of fuel
+for heating the air before admitting it into the motor.
+That special attention should be given to the improvement
+of air engines, and that with increased initial
+pressures at the central station the distance of the
+transmission can be very considerably augmented.
+Finally, Professor Riedler claims that power can be
+transmitted by compressed air more conveniently and
+more economically than by any other means.</p>
+
+<hr />
+
+[Continued from SUPPLEMENT, No. 802, page 12810.]
+
+<a name="me-1"></a><h2>THE BUILDERS OF THE STEAM ENGINE&mdash;THE FOUNDERS OF MODERN INDUSTRIES
+AND NATIONS.<a name="FNanchor_1a"></a><a href="#Footnote_1a"><sup>1</sup></a></h2>
+
+<h3>By Dr. R.H. THURSTON, Director of Sibley College,
+Cornell University.</h3>
+
+<p>Papin, Worcester, Savery, were the authors of the
+period of application of the power of steam to useful
+work in our later days. The world was, in their time,
+just waking into a new life under the stimulus of a new
+freedom that, from the time of Shakespeare, of Newton,
+and of Gilbert, the physicist, has steadily become
+wider, higher, and more fruitful year by year. All the
+modern sciences and all the modern arts had their
+reawakening with the seventeenth century. Every
+aspect of freedom for humanity came into view in those
+days of a new birth. Both the possibility of the introduction
+of new sciences and of new arts and the power
+of utilizing all new intellectual and physical forces
+came together. The steam engine could not earlier
+have taken form, and, taking form, it could not have
+promoted the advance of civilization in the earlier
+centuries. The invention becoming possible of development
+and application, the promotion of the arts and
+of all forms of human activity became a possible consequence
+of its final successful introduction into the rude
+arts that it was to so effectively promote and improve.</p>
+
+<p>But the work of these inventors was in itself but
+little more important than that of the Greek inventor of
+the steam ælopile, for each brought forward a machine
+which was, from a business point of view, utterly
+impracticable, and which, in each case, only served to
+show that a better device might prove useful and lead
+the way to its introduction. The merit of the inventors
+of the eighteenth century was that they were <i>able</i> to
+lead the way, to point out the path to success, to furnish
+evidence of the value of the coming, crowning
+invention. The "fire engines," as they were then
+called, of these now famous men were merely contrivances
+by the use of which the pressure of confined
+steam of high tension could be brought to act on the
+surface of a mass of confined water, forcing it downward
+into pipes through which it was led off and
+upward to a higher level; and thus a mine could be
+drained, ineffectively and expensively to be sure, but
+vastly more satisfactorily than by the animal power
+of the time. The machine of Savery was the best of
+all; but that was only a somewhat improved and manageable
+rearrangement of the engines of Papin and
+Worcester. And, after all, Papin, the greatest man of
+science perhaps of his time, died in poverty; Worcester
+languished in prison his whole life, and the later
+efforts of his widow brought nothing by way of a
+return for his invention; nor did either they or their
+successor, Morland, make the introduction of the
+engine either general or remunerative.</p>
+
+<p>Savery, coming on the stage at more nearly the right
+time to seize upon an opportunity, gained more than
+either of his predecessors; but we have no evidence
+that he ever acquired any large compensation or met
+with any remarkable business success in the introduction
+of the rude engine which bore his name; nor did
+Desaguliers, the great philosopher, or even Smeaton, the
+great engineer, of the later years of that century, make
+any great success of it. It was reserved for Watt to
+reap the harvest. But, though he so effectively reaped
+where his predecessors had sown, Watt is not the
+greatest of the inventors of the steam engine, if we
+rate his standing by the magnitude of the improvement
+which marked his reconstruction of the engine.</p>
+
+<p>It was NEWCOMEN who made the modern steam
+engine.</p>
+
+<p>When Newcomen came forward the labors of Worcester
+in Great Britain had sufficed to attract the attention
+of all intelligent men to the character of the
+problem to be solved, and to convince them of its
+importance and promise. The work of Savery had
+shown the practicability of the solution of the problem,
+both in mechanics and finance. He succeeded,
+though under great disadvantages and comparatively
+inefficiently. Once the task had been performed,
+though ever so rudely, the rest came easily and promptly.
+The defects of the Savery system were at once
+recognized; its great wastes of heat and of steam were
+noted, and the fact that they were inherent in the system
+itself was perceived. A complete change of type
+of machine was obviously requisite; it was this which
+constituted the greatest invention in the whole history
+of the steam engine, from Hero's time to our own; and
+to Newcomen we owe more than to any other man who
+ever lived, the value of the invention itself being considered,
+and the importance of the services of its introducer
+being left out of consideration. No such
+complete and vital improvement and modification of
+the machine has ever been effected by any other man,
+Watt and Corliss not excepted. Newcomen and his
+comrade Calley&mdash;we do not know how the honors
+should be divided&mdash;produced the modern steam engine.
+Its predecessor, the Savery engine, had been a mere
+steam "squirt." Newcomen constructed an engine.
+Savery built a simple combination of cylindrical or
+ellipsoidal vessels which wastefully and at once performed
+all the several offices of engine, pump, condenser,
+and boiler; Newcomen divided the several
+elements among as many parts, each especially adapted
+to the performance of its task in the most effective
+manner&mdash;the condenser excepted; for that was Watt's
+principal invention&mdash;and thus produced the first steam
+engine in the modern sense of that term.</p>
+
+<p>It was Newcomen, not Watt, who gave us the train
+of mechanism that we now call the steam engine. It
+is to Newcomen, rather than Watt, that we owe the
+highest honors as an inventor in this series of the
+most important of all the products of the inventive
+genius of mankind. Newcomen brought into existence
+a new, the modern, type of engine, and effected the
+greatest revolution that has been recorded in the history
+of the arts. Without Newcomen, there might
+have been no Watt; without Watt, there very possibly
+may not even yet have been brought into existence
+that giant of our time, whose mighty powers are
+employed more effectively than ever those of Aladdin's
+genii, in building palaces, in transporting men and
+material, in doing the work of the whole world; promoting
+the welfare of the race, in a single century,
+more than had all the forces of matter and mind
+together in the whole previous history of the world.
+Newcomen laid down a foundation beneath our whole
+economic system, out of sight, almost, but the essential
+base, nevertheless, on which Watt and his successors
+have carried up the great superstructure which seems
+to us to-day so imposing; which is so tremendous in
+magnitude, importance, and result. If to any one man
+could be assigned the credit, it is Newcomen who is to
+be considered the inventor of the steam engine.</p>
+
+<p>James Watt, indisputably the great inventor that he
+was, found the steam engine ready to his hand, applied
+himself to its improvement, and made it substantially
+what it is to-day. His most important work, the most
+unique service performed by him, was, however, that
+of its adaptation and introduction to do the work of
+the world. James Watt was the inaugurator of the
+era of refinement of the machine already invented, and
+the greatest of its builders and distributors. His inventions
+were all directed to the improvement of its
+details, and his labors to its introduction and its application
+to the myriad tasks awaiting it. By the hands
+of Watt it was made to pump water, to spin, to weave,
+to drive every mill; and he it was who gave it the
+form demanded by Stephenson, by Fulton, by the
+whole industrial world, for use on railway and
+steamboat, and in mill and factory, throughout the
+civilized countries of the globe. It was this great mechanic
+
+who showed how it might be made to do its
+work with least expense, with highest efficiency, with
+greatest regularity, with utmost concentration of
+power.</p>
+
+<p>The grand secret of his success was historical and
+economic, as much as scientific and mechanical. He
+brought out his inventions just when the world was
+economically and historically ready for them. The age
+of authority was past, that of freedom was come; the
+period of political and ecclesiastical tyranny was gone
+by, and that of the spontaneous development of man
+was arrived. The great invention was offered to a
+world ready and needing it, and, more than all, competent,
+for the first time in history, to make and use
+it.</p>
+
+<p>James Watt was himself a product of the modern
+scientific spirit. He was a man so constituted mentally
+that he could apply scientific methods to problems
+which his logical and clairvoyant mind could readily
+and exactly formulate the instant he was led to their
+consideration in the natural course of his progress. He
+was the ideal great inventor and mechanic. With
+inventive genius he combined strong common sense&mdash;not
+always a quality distinguishing the inventor&mdash;clear
+perception, breadth of view, and scientific method
+and spirit in the treatment of every question. His
+natural talent was re-enforced by an experience and an
+environment which led him to develop these ways and
+this mental habit. His trade was that of an instrument
+maker, his position was that of custodian and repairer
+of the apparatus of Glasgow University. He had for
+his daily companions and stimulus the great men and
+ozonized atmosphere of that famous institution. He
+kept pace with advancing science, and was imbued,
+both naturally and through contact with its promoters,
+with that ambition and those aspirations which are
+the life element of all progress, whether scientific or
+other. He was aware of the nature of the problems
+seeking solution at the time, and familiar with the
+state of his own art and that of the great mechanicians
+about him. Everything was favorable to his progress,
+so soon as he should be given an opportunity to take a
+step in advance and to come into sight at the front.
+The man and the time were both ready, and all conditions,
+internal and external, social and personal, were
+favorable to his development.</p>
+
+<p>The invention upon which Watt was to improve was
+at his hand. A word in regard to its status at the
+moment will throw some light upon that of Watt and
+his creation. Newcomen had, as we have seen, produced
+the modern type of steam engine as an original
+and wholly novel invention. But this machine, marvelous
+as an advance upon pre-existing forms of the
+steam engine, was still, as seen in the light of recent
+knowledge and experience, exceedingly defective. The
+purpose of a steam engine is to convert into usefully
+applicable power the hidden energy of fuel, stored
+ages ago in the earth, by transformation, through the
+action of vegetation, from the original form, the heat
+of the sun, into an available form for reconversion,
+through thermodynamic operations. In this process
+of reconversion, whatever the nature of the machine
+used in the operation, there are invariably wastes,
+both of heat required for conversion into power and of
+the power thus produced. That machine which effects
+the most complete transmutation of the heat supplied
+it into mechanical power, which wastes the least amount
+of heat supplied and of power produced, is the best
+engine, and constitutes an advance over every other.</p>
+
+<p>It was this reduction of wastes that made the Newcomen
+engine so much superior to that of Savery. The
+latter was by far the simpler and less costly construction;
+but its enormous losses, both of heat and of power,
+mainly the former, however, made it an extravagant
+expenditure of money to buy and use it. The Newcomen
+engine, costly and cumbrous, comparatively,
+nevertheless wasted so much less heat and steam and
+fuel that no one could afford to buy the cheaper machine.
+Before considering what Watt accomplished, we
+may find it profitable to examine into the nature of
+the wastes which characterized this later and better
+machine on which he effected his improvements.</p>
+
+<p>The Newcomen engine consisted of a steam boiler, a
+steam cylinder, a beam and a set of pumps. By making
+the boiler do its work separately, the engine acting
+independently, and the pumps as a detached portion
+of the mechanism, this inventor had reduced to an
+enormous extent those wastes of heat and of steam and
+of fuel which were unavoidable in the older machines
+in which all these parts were represented by a single
+vessel, or by two at most, in each element. In the
+Savery engine, the steam entering first heated up the
+interior of the working vessel to its own temperature,
+and held it at that temperature in spite of the cooling
+influence of the water present. This consumed large
+quantities of heat. It then was compelled to surrender
+probably much greater quantities still to the water
+itself, coming in direct contact as it did with its surface.
+If the water was agitated, either by the currents
+produced during its ingress or by the impact of the
+steam entering the vessel, this heating action penetrated
+to considerable depths and perhaps even warmed
+the whole mass very far above its initial temperature.
+This constituted another and a very serious loss. Then,
+again, as the water was gradually driven out of the
+containing vessel by the steam pressing on its surface,
+new portions of the vessel and new masses of water
+were continually brought in contact with the hot steam,
+taking its full temperature, and thus, often, probably,
+finally heating the whole mass of the forcing vessel,
+and a large proportion of the water as well, up to the
+temperature, approximately at least, of the steam itself.
+Thus in many instances, if not always, vastly more heat
+and steam were wasted, in this undesirable heating
+of water and forcing vessel, than were usefully employed
+in the legitimate work of raising the water to a
+higher level. In fact, in some cases in which these
+quantities were measured, the wastes were one hundred
+times as much as the work done. One per cent.
+of the heat supplied did the work; while ninety-nine
+per cent. was thrown away. One dollar or one
+shilling expended for fuel to do the work was accompanied
+by an expenditure of ninety-nine dollars or
+shillings thrown away, because of the imperfections of
+the system and machine. The whole history of the
+development of the steam engine has been one of
+gradual reduction of these wastes; until to-day, our
+best engines only compel us to spend five dollars for
+wastes to each dollar paid out for useful work. A
+business man would think that amply extravagant,
+however, and the man of science is continually seeking
+methods of evading these losses, a large proportion of
+which are now apparently unavoidable in heat engines,
+by finding some new system of heat and energy transformation.</p>
+
+<p>Watt was the instrument maker and repairer at Glasgow
+University in the year 1763. His companions were,
+among others, the professors of natural philosophy and
+of mathematics in the university. Their conversation
+and their frequent presentation of practical and scientific
+questions and problems stimulated his naturally
+inquiring and inventive mind to the pursuit of a thousand
+interesting and promising schemes for the improvement
+of existing methods and machinery. Dr.
+Robison, then a student, suggested the invention of a
+steam carriage for use on common roads, and the young
+mechanician at once began experiments that, resulting
+in nothing at the time, were nevertheless continued, in
+one or another form, until all modern applications of
+steam came into view. Dr. Black taught Watt chemistry,
+then a newly constructed science, and led him on
+to the discovery, finally made by them independently,
+of the fact and the magnitude of the latent heat of
+steam; the discovery coming of a series of scientifically
+planned and accurately conducted investigations, such
+as the man of science of to-day would deem creditable.
+The treatises of Desaguliers and others on physics gave
+Watt a knowledge of that domain of natural phenomena
+which stood him in good stead later, when he
+attempted to apply its principles to the reduction of
+the wastes of the steam engine.</p>
+
+<p>It was while at Glasgow University, working under
+such influences and in such an atmosphere of intellectual
+activity, that the accident of the Newcomen
+model engine needing repair brought to the mind of
+Watt the opportunity which, availed of at once, made
+him famous and gave the world its greatest aid, its
+most powerful servant. The observing mind of the
+great mechanic immediately noted its defects, sought
+their causes, found their remedy. He discovered, at
+once, that the quantity of steam entering the cylinder
+of the little engine has four times the volume of the
+cylinder receiving it: in other words, three-fourths of
+that steam must be condensed immediately on entrance.
+This meant, evidently, that only one-fourth
+of the steam supplied was utilized, and even then inefficiently,
+in doing its work. The reason of this was as
+easily seen, immediately the fact was revealed. As Watt
+himself expressed it, the causes of this loss, causes
+which would obviously be exaggerated in a small
+engine, were: "First, the dissipation of heat by the
+cylinder itself, which was of brass and both a good
+conductor and a good radiator. Secondly, the loss of
+heat consequent upon the necessity of cooling down the
+cylinder at every stroke in producing the vacuum.
+Thirdly, the loss of power due to the pressure of vapor
+beneath the piston, which was a consequence of the
+imperfect method of condensation." This much determined,
+the next step looked toward the confirmation
+of his conclusions and the remedy of the defects.</p>
+
+<p>To meet the first difficulty he made a cylinder of
+wood, soaked in oil and baked, a non-conducting and
+non-radiating material. Then he was able to determine
+with some accuracy the quantities of steam and
+injection water used in the engine; and a comparison
+with the original cylinder and its operation showed
+that not only four times the quantity of steam, but also
+four times the amount of injection water was used as
+was necessary, assuming wastes checked. Further
+scientific research on the part of Watt gave him measures
+of specific heats of the metals and of wood, the
+specific volumes of steam at various working pressures,
+the evaporative efficiency of boilers, the pressures and
+temperatures of steam in the boiler under specified
+conditions, the quantities of steam and of water required
+for the operation of his little condensing
+engine.</p>
+
+<p>Then came his enunciation of the grand principle of
+economy in the construction and operation of the steam
+engine: "Keep the cylinder as hot as the steam which
+enters it," as he expressed it. This was Watt's guiding
+principle, as it has been that of all his successors in the
+improvement of the economic performance of the steam
+engine and of all other heat engines. The great source
+of waste is the dispersion of heat, uselessly, which
+should be applied to the production of work by its
+transformation, thermodynamically, into the latter
+form of energy. The second form of waste is that of
+power thus produced in the unprofitable work of moving
+the parts of the engine itself; and the third is that
+of heat by transfer, without transformation, by conduction
+and radiation to surrounding bodies. In
+modern engines, the latter is but three or five per cent.,
+in the best cases; the second waste constitutes perhaps
+ten per cent.; while the first of these losses
+amounts very usually to seventy per cent., of which
+last one-third or one-fourth is of the kind discovered
+by Watt, the rest being the thermodynamic waste incident
+to all known methods of operation of heat
+engines, and apparently unavoidable. In our very
+best and largest engines, the waste found by Watt to
+constitute three fourths of all heat supplied has been
+brought down to ten per cent., a fact which well exemplifies
+the advances made since his time of apprenticeship
+by himself and his successors of this nineteenth
+century. The steam engine of to-day, in its most successful
+operation, gives us twenty-five times as much
+power from a pound of coal as did the engine that the
+great inventor sought to improve: this is the magnificent
+fruit of that one discovery of James Watt,
+and of application of the simple principle which he so
+concisely and clearly stated.</p>
+
+<p>The method adopted by Watt to secure a remedy,
+so far as practicable, of this defect of the older machine
+was as simple and as perfect as was the principle
+which it embodied. He first removed from the cylinder
+the prime source of its wastes; providing a separate
+condenser, and thus avoiding the repeated chilling
+of its surfaces by the cold water used in condensing
+the steam at exhaust, and also permitting its strokes
+to be made with far greater frequency, thus giving less
+time for cooling by the influence of the remaining
+vapors after condensation. He next went still further,
+and provided the cylinder with a closed top, keeping
+out the air, and a "jacket" of hot boiler steam to
+<i>keep</i> it as hot as the steam which entered it. These
+were the two great improvements which converted the
+first real steam engine into an economical form of heat
+engine and essentially finished the work so grandly begun
+by Newcomen and Calley. These changes gave
+
+us the modern steam engine; and these are Watt's
+first and greatest, but by no means only, contributions
+to the production of the modern world with all its
+comforts, its luxuries and its opportunities for material,
+intellectual and moral advancement of individual
+and of race. His work was to this extent complete in
+1765.</p>
+
+<p>But Watt did not stop here. There still remained
+for him the no less important and the, in some senses,
+still more imposing, work of finding employment for
+the new servant of mankind and of setting it at its
+work of giving the human arm a thousand times
+greater strength, to the mind of man uncounted opportunities
+to promote the advancement of knowledge,
+of civilization, of every good of the race. His was still
+the task of adapting the new machine to all the purposes
+of modern industry. It had been hitherto confined
+to the task of raising water from the depths of
+the mine; it was now to be harnessed to the railway
+train; to be made to drive the machinery of the mill,
+to apply its marvelous power to the impulsion of the
+river boat and ocean steamer; to furnish energy,
+through endless systems of transfer and use, to every
+kind of work that man could devise and should invent.
+All this meant the giving of the machine forms as various
+as the purposes to which it was to be devoted. It
+had previously only raised and depressed a rod; it must
+now turn a shaft. It had then only operated a pump;
+it must now turn a mill, grind our grain, spin our
+threads, weave our cloths, drive our shops and factories,
+supply the powerful blast of the iron furnace. It
+must be made to move with the utmost conceivable
+regularity, and must, with all this, do its work in the
+development of the hidden energy of the fuel, with
+the greatest possible economy, through the expansion
+of its steam. All this was achieved by James Watt.</p>
+
+<p>The invention of the double-acting engine, in which
+the impulsion of the steam is felt both in driving the
+piston forward and in forcing it backward, both upward
+and downward, the application of its force
+through crank and fly wheel, the creation of an automatic
+system of governing its speed, and the discovery
+of the economy due to its complete expansion,
+were all improvements of the first magnitude, and of
+the greatest practical importance; and all these were
+in rapid succession brought into existence by the creative
+mind that had apparently been brought into the
+world for the express purpose of giving to the hand of
+man this mighty agent, to perfect the mightiest power
+that mind of man has yet conceived.</p>
+
+<p>But to do the rest required more than inventive
+genius and mechanical skill. It demanded capital and
+the stored energy of labor and genius in other fields,
+directed by the mind of a great "captain of industry."
+This came to Watt through Matthew Boulton, a manufacturer
+of Birmingham, whose father and ancestors
+had gradually and toilsomely, as always, accumulated
+the property needed for the prosecution of a great
+business. The combination of genius and capital is
+always an essential to success in such cases; and
+good fortune, a Providence, we may well say, brought
+together the genius and the capitalist to do their work,
+hand in hand, of providing the world with the steam
+engine. Hand in hand they worked, and all the world
+to-day, and the race throughout its future life, must
+testify gratitude for the inexpressible obligations under
+which these two men have placed them, doing the
+work of the world.</p>
+
+<p>Boulton &amp; Watt, the capitalist with the inventor,
+gave the world the steam engine, finally, in such form
+and in such numbers that its permanent establishment
+as the servant of man was insured. The capitalist was
+as essential an element of success as was the inventor,
+and, in this instance, as in a thousand others, the race
+is indebted to that much-abused friend of the race, the
+capitalist, for much that it enjoys of all that it desires.
+The industry and patience, the skill and the wisdom
+required for the accumulation of this energy stored for
+future use in great enterprises is as important, as essential,
+as inventive power or any other form of genius.
+Talent and genius must always aid each other. This
+firm was established in 1764 and its main resources,
+aside from the bank account, were Watt's patent,
+about expiring, and Watt's genius, and Boulton's talent
+as a man of business. The patent was extended
+for twenty-four years, the new inventions of Watt, now
+beginning to pour from his prolific brain in a wonderful
+stream, were also patented, and the whole works
+were soon employed upon the construction of engines
+for which numerous orders soon began to pour in upon
+the now prosperous builders. The patent law established
+Boulton and Watt and the firm paid back the
+nation with handsome usury, giving it unimaginable
+profits indirectly through its control of the work of the
+world and large profits directly through the business
+brought them from all parts of the then civilized globe.
+There has never, in the history of the world, been a
+more impressive illustration of the value to a nation of
+that generous public policy, that simply just legislation,
+which gives to the man of brain control of the
+products of his mind. For a hundred years, Great
+Britain has, largely through her encouragement of the
+inventor and her protection of his mental property by
+securing the fruits of his labors, in fair portion, to him,
+gained the power of dictating to the world and has
+gained an advance that cannot be measured. Watt
+and Arkwright and Stephenson and Crompton and their
+ilk, protected by their government and its patent laws,
+made their country the peaceful conqueror of the
+world. The story of the work of the inventor is a
+poem of mighty meaning and of wonderful deeds. The
+inventor proved himself a mightier magician than
+ever the world had seen.</p>
+
+<p class="ind">
+"A creature he called to wait on his will,<br />
+Half iron, half vapor&mdash;a dread to behold;<br />
+Which evermore panted, and evermore rolled,<br />
+And uttered his words a millionfold."</p>
+
+
+<p>Such was the outcome of this grand modern "trust,"
+a combination of the wisest legislation, the most brilliant
+invention, and the most wisely applied capital.
+There are "trusts" of which the outcome is most beneficent.</p>
+
+<p>Since the days of Watt, the improvement of the
+steam engine and the work of inventors has been confined
+to matters of detail. All the fundamental principles
+were developed by Watt and his predecessors and
+contemporaries and it only was left to his successors to
+find the best ways of carrying them into effect. But
+these matters of detail have been found to involve opportunities
+
+to make enormous strides in the direction
+of securing improved efficiency of the machine. The
+further application of the principle which led Watt to
+his greatest inventions; of the principle, keep the
+cylinder as hot as the steam which enters it, of that
+which he enunciated relative to the advantage of expanding
+steam, and of that affecting the regulation of
+the machine; have reduced the costs of steam and of
+fuel to a small fraction of their earlier magnitude. One
+ton of engine to-day does the work of eight or ten in
+the time of Watt: one pound of fuel or of steam gives
+to-day ten times the power then obtained from it. A
+steamship now crosses the Atlantic in one-eighth the
+time required by the famous "liner" of the "Black
+Ball Line." The wastes of the engine have been
+brought down from above eighty per cent. to eight;
+and a half-ounce of fuel on board ship will now transport
+a ton of cargo over a mile of ocean.</p>
+
+<p>FREDERICK E. SICKELS gave us the first practicable
+form of expansion gear in 1841; GEORGE H. CORLISS
+gave a new type of engine of marvelous perfection and
+economy in 1849; Noble T. Green, Wm. Wright and
+many less well known but no less meritorious inventors
+have since done their part in the transformation
+of the old engine of Watt into the modern wonder of
+concentrated and economical power, and marvel of
+accurate and beautiful design and workmanship. The
+"trip cut-off," with reduced clearances, increased boiler
+pressure, higher rates of expansion, accelerated speeds
+of engine, better construction in all respects, as well as
+improved design, have enabled us to avail ourselves to
+the utmost of the principles of Watt, and our mills, our
+railways, our steamers and our fields, even, have
+gained almost as extraordinarily by these advances,
+since the days of the great inventor, as through his
+immediate labors.</p>
+
+<p>With the introduction of the new form of older energy,
+electricity, with the reduction of the lightning
+into thraldom, has now come a new impulse affecting
+all the industries. Through its mysterious, its still unknown
+action, steam now reaches out far from its own
+place, driving the electric car along miles of rail; giving
+light throughout all the country about it, turning
+night into day, and repressing crime while encouraging
+legitimate labor, reaching into distant chambers and
+every little workshop, to offer its powerful aid in all the
+distributed work of cities. Without the steam engine
+there would be little work available for electricity, but
+the appearance of this, the latest and most useful
+handmaid of steam, has given the engine work to do
+in an uncounted number of new fields, has called in the
+inventor once more to adapt steam to its new work.
+The "high-speed engine" is the latest form of the
+universal helper. And such has been the readiness
+and the intelligence of the contemporary inventor that
+we now have engines capable of turning their shafts
+three hundred rotations a minute and without a perceptible
+variation of velocity, whatever the change of
+load or the suddenness with which it is varied. In the
+days of Watt a fluctuation of five per cent. in speed
+was thought wonderfully small; in those of Corliss, the
+variation was restricted to two per cent. and we wondered
+at this unanticipated success. To-day, thanks
+to Porter and Allen, to Hartnell, to Hoadley, to Sims,
+to Thomson, to Sweet, to Ide, and to Ball, we have
+seen the speed fluctuation restricted to even less than
+one per cent. of its normal average.</p>
+
+<p>The inventors of the steam engine are, through their
+representatives of to-day, according to the statisticians,
+doing the equivalent of twelve times the work of a
+horse, for every man, woman and child on the globe.
+We have not less, probably, than a half million of miles
+of railway, transporting something over 150,000,000,000
+of tons a mile a year. A horse is reckoned to haul a
+ton weight about six and a half miles, day by day, by
+the year together. In the United States, it is reckoned
+that the steam engine, on the railways alone, hauls a
+thousand tons one mile, for every inhabitant of the
+country, every year, or, if it is preferred to so state
+it, a ton a thousand miles. This is the way in which
+the East and the West are, by the inventors of the
+steam engine, enabled to help each other. This costs
+about $10 each individual; it would require some 25
+millions of horses to do the work, and would cost about
+$1,000 a family, which is more than twice the average
+family earnings.</p>
+
+<p>Dr. Strong, in that remarkable book, "Our Country,"
+says: "One man, by the aid of steam, is able to do the
+work which required two hundred and fifty men at the
+beginning of the century. The machinery of Massachusetts
+alone represents the labor of more than 100,000,000
+men, as if one-half of all the workmen of the
+globe had engaged in her service." And again: "Some
+thirty years ago, the power of machinery in the mills
+of Great Britain was estimated to be equal to 600,000,000
+men, or more than all the adults, male and female,
+of all mankind." Mr. Gladstone estimated that the
+aggregation of wealth on the globe during the whole
+period from the birth of Christ to that of Watt was
+equaled by the production in twenty years, at the middle
+of this century, with the aid of machinery driven
+by the fruit of the brain of the inventors of the steam
+engine. We may probably now safely estimate the
+former quantity as rivaled in less than five years,
+while, since the birth of Watt and his engine, and the
+production of the spinning mule, the power loom, the
+cotton gin and our own patent system and its marvelous
+mechanism, all events of a century ago, we may
+estimate that they have, together, accomplished more
+in this period which we now celebrate than could have
+been done in a millenium of milleniums without these
+now subjected genii. But the power behind all these
+curious inventions and their work is that of steam.
+The steam engine even supplies power to the telegraph
+and transports words and thought as well as cotton
+bales and coal.</p>
+
+<p>And now what has this combination of legislation
+for private protection and public good, of a genius
+producing great inventions, and of the accumulated
+capital of earlier years, brought about?</p>
+
+<p>It has given us the best fruits of science in permanent
+possession. The study of science invariably aids,
+in a thousand ways, the progress of mankind. It gives
+us new conceptions of nature and of the possibilities of
+art; it promotes right ways of work and of study; it
+teaches the inventor and the discoverer how most surely
+and promptly to gain their several ends, it gives the
+world the results of all acquired knowledge in concrete
+form. This one instance which we are now especially
+interested in contemplating has performed more wonderful
+miracles than ever Aladdin's genii attempted.
+One man, with a steam engine at his hand, turns the
+wheels of a great mill, drives forty thousand spindles,
+applies a thousand horse power to daily work in the
+spinning of threads, the weaving of cloth, the impulsion
+of a steamboat, or the drawing of great masses of
+hot iron into finest wire. This puny creature, his
+mind in his finger tips, exerts the power of ten thousand
+men, working with muscle alone, and, aided by a
+handful of women, boys and girls, clothes a city. A
+half dozen men in the engine room of an ocean steamer,
+with a hundred strong laborers in the boiler room
+and on deck, transports colonies and makes new nations,
+brings separated peoples together, unites countries on
+opposite sides of the globe, brings about easy exchanges
+between pole and equator. One man on the
+footboard of the locomotive, one man shoveling into
+the furnaces the black powder that incloses the energy
+stored in early geological ages, a half dozen men
+mounted on the long train of following vehicles, combine
+to bring to the mill girl in Massachusetts, the
+miner in Pennsylvania, the sewing woman, and the
+wealthy merchant, her neighbor in New York, the
+flour made in Minnesota from the grain harvested a
+few weeks earlier in Dakota. All the world is served
+faithfully and efficiently by this unimaginable power,
+this product of the brain of the inventor, protected by
+the law, stimulated and aided by the capital that it
+has itself almost alone produced.</p>
+
+<p>And thus have the inventors of the steam engine set
+in motion and placed at the disposal of mankind for
+every form of useful work all the great forces of nature;
+thus Hero of Alexandria touched the then concealed
+spring which called all the genii of earth, fire,
+water and air to do the bidding of the race. Thus Papin,
+Worcester, Newcomen, Watt, and Corliss and others
+of our own contemporaries, have applied the genii to
+their task of leveling mountains, traversing seas, continents,
+and the depths of the earth, building ships,
+locomotives, hamlets and cities, cottages and palaces,
+turning the spindle, operating the loom, and setting
+motion and giving energy to every machine, doing the
+work of thousands of millions of men, converting barbarism
+into civilization, giving necessaries of life in
+profusion, comforts in plenty, and luxuries in superabundance.</p>
+
+<p>Aiding and working hand in hand with those other
+genii of progress, the inventors of the printing press
+and of the telegraph, the telephone, and the electric
+railway, of the modern system of textile manufactures,
+of iron and steel making, of the mowing machine and
+the harvester, they have compressed into two centuries
+the progress of a millennium, destitute of their aid.
+Every step taken under their stimulus, and with their
+help, is a step toward a higher life for all, intellectually
+and morally as well as physically; every advance in
+the improvement of their work is a gain to every man,
+woman, and child; every improvement of the steam
+engine is a help to the whole world. This progress
+makes the day of the extinction of the system now
+grinding the populations of the earth into the ground,
+the day of the abolition of armies and the restoration
+to the people of that freedom which characterized the
+times of the patriarchs, and of the restoration of the
+rights of the citizen to his own time and strength and
+producing power, perceptibly nearer.</p>
+
+<p>When this final revolution shall have been accomplished,
+and when all the world has settled down to
+the steady and undisturbed work of production by
+daily and regular labor, aided by the genii of steam,
+of electricity, of all nature, combined for good, the results
+of the intellectual activity of the inventors of the
+steam engine will be fully seen. Then no monument
+will be required to keep green the memory of Watt,
+Corliss, or any other of these great men, but it will be
+said of them, as of Sir Christopher Wren in the epitaph
+in St. Paul's: "Seek you a monument, look about
+you!" Every wreath of steam rising to the heavens
+from factory, mill or workshop will be a reminder of
+Hero of Alexandria, every mine will possess a memorial
+to Papin, Worcester and Savery; every steamship will
+bring into grateful memory Fitch and Stevens, and
+Bell and Fulton; thousands of locomotives, crossing the
+continents, will perpetuate the thought of the Stephensons
+and their colleagues in the introduction of the
+railway; the hum of millions of spindles and the music
+of the electric wire will tell of the work of Corliss and
+his contemporaries and successors who made these
+things possible, and all kingdoms and races, all nations,
+will revere the name of James Watt, the genius to
+whom the world is most indebted for the beginnings of
+all this later and grander civilization which has converted
+the slow progress of earlier centuries into the
+meteor-like advance of to-day toward a future as
+grand and as mighty and as noble as humanity shall
+choose to make it.</p>
+
+<a name="Footnote_1a"></a><a href="#FNanchor_1a">[1]</a><div class="note">
+An address delivered at the Centennial Celebration of the American
+Patent System, Washington, April, 1891.</div>
+
+<hr />
+
+<a name="rr-1"></a><h2>IMPROVED HAND CAR.</h2>
+
+<p class="ctr">
+<img src="images/13a.png" alt="Hand Car Illustration" title="">
+</p>
+
+<p>In the accompanying illustration we show a new design
+of hand car, being introduced by the Courtright
+Manufacturing Co., of Detroit. It will be seen that
+the apparatus for propelling the car is very different
+from the mechanism generally used. An upright framework
+secured to the platform carries a large sprocket
+wheel, which is connected to a smaller one upon one
+of the axles by means of a chain. The larger sprocket
+wheel is rotated by means of a triangular shaped lever
+attached at the lower corner to the crank of the sprocket
+wheel and having a handle at each of its upper corners.
+It is hinged upon a fulcrum which slides upon
+the two vertical rods shown in the illustration. It will
+be seen that this gives a peculiar movement to the
+handles by which the operators propel the car, but it
+has been found that the motion is an excellent one,
+and it is claimed that a higher speed can be obtained
+with the mechanism here shown than with any other
+now in use. There is practically no dead center, as in
+the case where the ordinary crank and lever is used.
+A number of leading roads have given the car a trial,
+and being well satisfied it, have given orders for more.
+The company claim that a car with 20 in. wheels can
+easily be made to attain a speed of 15 miles an hour by
+two men.&mdash;<i>Railway Review</i>.</p>
+
+<hr />
+
+<a name="math-1"></a><h2>THE CONIC SECTIONS.</h2>
+
+<h3>By Prof. C.W. MACCORD, Sc.D.</h3>
+
+<p>In Fig. 1 let D be a given point, and O the center of
+a given circle, whose diameter is FG. Bisect DF at
+A. Also about D describe an arc with any radius DP
+greater than DA, and about O another arc with a radius
+OP = DP + FO, intersecting the first arc at P,
+then draw PD, and also PO, cutting the circumference
+of the given circle in L. Since PD = PL, and
+DA = AF, it is evident that by repeating this process
+we shall construct a curve PAR, which satisfies the
+condition that <i>every point in it is equally distant from
+a given point and from the circumference of a given
+circle</i>. Since PO-PD = LO, and AO-AD = FO,
+this curve is one branch of the hyperbola of which D
+and O are the foci.
+<img src="images/14-fig1.png" align="left" alt="FIG. 1" title="">
+</p>
+
+<p>Bisect DG at B, then about D describe an arc with
+any radius DQ greater than DB, and about O another
+are with radius OQ = DQ-FO; draw from Q the
+intersections of these arcs, the line QD, and also QO,
+producing the latter to cut the circumference in E. By
+this process we may construct the curve QBZ, each
+point of which is also equally distant from the given
+point D, and from the concave instead of the convex
+arc of the given circumference. The difference between
+QD and QO being constant and equal to FO, and AB
+being also equal to FO, this curve is the other branch
+of the same hyperbola, whose major axis is equal to
+the radius of the given circle.</p>
+
+<p>The tangent at P bisects the angle DPL, and is perpendicular
+to DL, which it bisects at a point I on the
+circumference of the circle whose diameter is AB, the
+major axis, the center being C, the middle point of DO.
+As P recedes from A, it is evident that the angles
+P D L, P L D, will increase, until DL assumes the
+position D T tangent to the given circle, when they
+will become right angles. P will therefore be infinitely
+remote, and the point I having then reached t, where
+D T touches the smaller circle, C t S will be an asymptote
+to the curve. This shows that the measurements
+from the convex arc, for the construction of A P, are
+made only from the portion FT of the given circumference.</p>
+
+<p>In the diagram the point Q is so chosen that DL
+produced passes through E, so that QJ, the tangent
+at Q, is parallel to PI. It will thus be seen that the
+measurements from the concave arc, for the construction
+of BQ, are confined to the portion G T of the
+given circumference. As DLE rises, the points P and
+Q recede from A and B, the points L and E approach
+each other, finally coinciding at T; at this instant I
+and J fall together at t, so that S S is the common
+asymptote to A P and B Q.</p>
+
+<p>
+<img src="images/14-fig2.png" align="right" alt="FIG 2." title="">
+In Fig. 2 the given point D lies within the circumference
+of the given circle. Bisect DF at A, and DG
+at B; about D describe an arc with any radius DP
+greater than DA, and about O another, with radius
+OP = OF&nbsp;-&nbsp;DP, these arcs intersect in P, and producing
+OP to cut the circumference in L, we have PD = PL.
+Similarly ED = EH, UD = UW, etc.
+And since PD + PO = LP + PO, DE + EO = HE
++ EO, and so on, the curve is obviously the ellipse of
+which the foci are D and O, and the major axis is AB
+= FO, the radius of the given circle.</p>
+
+<p>If, as in Fig. 3, the given point be made to coincide
+with the center of the circle, the ellipse becomes a
+circle with diameter A B = F O. But if the point be
+placed upon the circumference, as in Fig. 4, the ellipse
+will reduce to the right line A B coinciding with FO.
+
+<img src="images/14-fig3456.png" align="left" alt="FIGs 3, 4, 5, 6." title="">
+</p>
+
+<p>In this case we may also apply the same process as in
+Fig. 1; D T becomes a tangent at D to the circumference,
+and the asymptotes coincide with the axis of the
+hyperbola, of which one branch reduces to the right
+line A P extending from A to infinity on the left, and
+the other reduces to the right line B G Q, extending
+from B to infinity on the right.</p>
+
+<p>If the circle be reduced to a point, as in Fig. 5, the
+resulting locus is a right line perpendicular to and bisecting
+D O. If on the other hand the diameter of the
+given circle be infinite, the circumference, as in Fig. 6,
+becomes a right line perpendicular to the axis at F, and
+the curve satisfies the familiar definition of the parabola,
+D E being equal to E H, D P equal to P L, and
+so on.</p>
+
+
+<p>
+<img src="images/14-fig7.png" align="right" alt="FIG 7." title="">
+In Fig. 7, as in Fig. 1, DT is tangent at T to the
+given circle whose center is O, and at t to the circle
+about C whose diameter is AB, the major axis. Since
+DTO is a right angle, T lies upon the circumference
+of the circle whose center is C, and diameter DO; this
+circle cuts the asymptote SCS at M and N. The
+semi-conjugate axis is a mean proportional between D
+A and AO; now drawing TM and TN, it is seen
+that Tt is that mean proportional; and a circle described
+about C with that radius will be tangent to TO. DT,
+then, is the radius of the circle to be described about the
+focus of the conjugate hyperbola for its construction
+according to the enunciation first given: and we observe
+that DT and TO are supplementary chords in
+the circle about C through D and O. The conjugate
+foci must therefore lie upon this circumference, at D'
+and O'; and since D'O' is perpendicular to DO, D'T
+will be perpendicular and T'O' will be parallel to
+SCS.</p>
+
+
+
+<p>Now as TO increases, T'O' will diminish, until,
+when TO equals DO, T'O' will vanish and with it
+Ct'; and at this crisis, the case is the same as in Fig.
+4; but the conjugate hyperbola logically reduces to
+<i>two</i> right lines, extending from C to infinity on the
+right and left. As indeed it should from the familiar
+construction, since the distances from D' and O' to any
+point on the horizontal axis being equal, their difference
+is constant and equal to zero.</p>
+
+<p>It appears, then, that a conic section may be defined
+as the locus of a point which is equally distant from a
+given point and from the circumference of a given circle.
+Boscovich defines it as the locus of a point so moving
+that its distances from a given point and from a
+given right line shall have a constant ratio.</p>
+
+<p>The latter definition involves the conceptions of a
+rectilinear directrix, and a varying ratio in the cases
+of the different curves, this ratio being unity for the
+parabola, less for the ellipse, and greater for the hyperbola.
+The former involves the conception of a circular
+directrix with a ratio equal to unity in all cases; and
+the two definitions become identical in the construction
+of the parabola, which is in fact the only curve
+of which a clear idea is given by either of them. That
+of Boscovich has been given a prominence far in excess
+of its merits, being made the foundation for the discussion
+of these important curves, and this in a textbook
+whose preface contains the following true and
+emphatic statement, viz.:</p>
+
+<blockquote>
+"The abstract nature of a ratio, and the fact that it
+is a compound concept, peculiarly unfit it for elementary
+purposes."
+</blockquote>
+
+<p>The definition herein set forth has not been given in
+any treatise on the subject, so far as we have been able
+to ascertain. And it is presented with the distinctly
+expressed hope that it never will be, except as a mere
+matter of abstract interest.</p>
+
+<p>Of this it may, like the other, possess a little, but
+both have the great disadvantage that, except in relation
+to the parabola, the idea which they convey to
+the mind of the curves to which they relate, if indeed
+they convey any at all, is most obscure and indirect;
+and of practical utility neither one can claim a particle.</p>
+
+<hr />
+
+<a name="chem-2"></a><h2>TABLE OF ATOMIC WEIGHTS.</h2>
+
+<h3>(Issued December 6, 1890.)</h3>
+
+<p>By request of the Committee of Revision and Publication
+of the Pharmacopoeia of the United States of
+America, Prof. F.W. Clarke, chief chemist of the
+United States Geological Survey, has furnished a table
+of atomic weights, revised upon the basis of the most
+recent data and his latest computations. The committee
+has resolved that this table be printed and furnished
+for publication to the professional press. The
+committee also requests that all calculations and analytical
+data which are to be given in reports or contributions
+intended for its use or cognizance be based
+upon the values in the table. It would be highly desirable
+that this table be adopted and uniformly followed
+by chemists in general, at least for practical
+purposes, until it is superseded by a revised edition. It
+would only be necessary for any author of a paper,
+etc., to state that his analytical figures are based upon
+"Prof. Clarke's table of atomic weights of December
+6, 1890," or some subsequent issue.</p>
+
+<p>This table represents the latest and most trustworthy
+results, reduced to a uniform basis of comparison, with</p>
+
+<p>oxygen = 16 as starting point of the system. No decimal
+places representing large uncertainties are used.
+When values vary, with equal probability on both
+sides, so far as our present knowledge goes, as in the
+case of cadmium (111.8 and 112.2), the mean value is
+given in the table.</p>
+
+<p>The names of elements occurring in pharmaceutical,
+medicinal, chemicals, are printed in italics:</p>
+
+<div class="ctr">
+<table summary="Auto-table" cellspacing="10">
+<colgroup span="3">
+<col align="left">
+<col align="center">
+<col align="center">
+</colgroup>
+<thead>
+<tr><th>Name.</th><th>Symbol.</th><th>Atomic Weight.</th></tr>
+</thead>
+<tbody>
+<tr><td><i>Aluminum.</i></td><td><i>Al</i></td><td>27.  </td></tr>
+<tr><td><i>Antimony.</i></td><td><i>Sb</i></td><td>120.  </td></tr>
+<tr><td><i>Arsenic.</i></td><td><i>As</i></td><td>75.  </td></tr>
+<tr><td><i>Barium.</i></td><td><i>Ba</i></td><td>137.  </td></tr>
+<tr><td><i>Bismuth.</i></td><td><i>Bi</i></td><td>208.9 </td></tr>
+<tr><td><i>Boron.</i></td><td><i>B</i></td><td>11.  </td></tr>
+<tr><td><i>Bromine.</i></td><td><i>Br</i></td><td>79.95 </td></tr>
+<tr><td>Cadmium.</td><td>Cd</td><td>112.  </td></tr>
+<tr><td>Caesium.</td><td>Cs</td><td>132.9 </td></tr>
+<tr><td><i>Calcium.</i></td><td><i>Ca</i></td><td>40.  </td></tr>
+<tr><td><i>Carbon.</i></td><td><i>C</i></td><td>12.  </td></tr>
+<tr><td><i>Cerium.</i></td><td><i>Ce</i></td><td>140.2 </td></tr>
+<tr><td><i>Chlorine.</i></td><td><i>Cl</i></td><td>35.45 </td></tr>
+<tr><td><i>Chromium.</i></td><td><i>Cr</i></td><td>52.1 </td></tr>
+<tr><td>Cobalt.</td><td>Co</td><td>59.  </td></tr>
+<tr><td>Columbium.<a name="FNanchor_1b"></a><a href="#Footnote_1b"><sup>1</sup></a></td><td>Cb</td><td>94.  </td></tr>
+<tr><td><i>Copper.</i></td><td><i>Cu</i></td><td>63.4 </td></tr>
+<tr><td>Didymium.<a name="FNanchor_2"></a><a href="#Footnote_2"><sup>2</sup></a></td><td>Di</td><td>142.3 </td></tr>
+<tr><td>Erbium.</td><td>Er</td><td>166.3 </td></tr>
+<tr><td>Fluorine.</td><td>F</td><td>19.  </td></tr>
+<tr><td>Gallium.</td><td>Ga</td><td>69.  </td></tr>
+<tr><td>Germanium.</td><td>Ge</td><td>72.3 </td></tr>
+<tr><td>Glucinum.<a name="FNanchor_3"></a><a href="#Footnote_3"><sup>3</sup></a></td><td>Gl</td><td>9.  </td></tr>
+<tr><td><i>Gold.</i></td><td><i>Au</i></td><td>197.3 </td></tr>
+<tr><td><i>Hydrogen.</i></td><td><i>H</i></td><td>1.007  </td></tr>
+<tr><td>Indium.</td><td>In</td><td>113.7 </td></tr>
+<tr><td><i>Iodine.</i></td><td><i>I</i></td><td>126.85  </td></tr>
+<tr><td>Iridium.</td><td>Ir</td><td>193.1 </td></tr>
+<tr><td><i>Iron.</i></td><td><i>Fe</i></td><td>56.  </td></tr>
+<tr><td>Lanthanum.</td><td>La</td><td>138.2 </td></tr>
+<tr><td><i>Lead.</i></td><td><i>Pb</i></td><td>206.95 </td></tr>
+<tr><td><i>Lithium.</i></td><td><i>Li</i></td><td>7.02  </td></tr>
+<tr><td><i>Magnesium.</i></td><td><i>Mg</i></td><td>24.3 </td></tr>
+<tr><td><i>Manganese.</i></td><td><i>Mn</i></td><td>55.  </td></tr>
+<tr><td><i>Mercury.</i></td><td><i>Hg</i></td><td>200.  </td></tr>
+<tr><td><i>Molybdenum.</i></td><td><i>Mo</i></td><td>96.  </td></tr>
+<tr><td>Nickel.</td><td>Ni</td><td>58.7 </td></tr>
+<tr><td><i>Nitrogen.</i></td><td><i>N</i></td><td>14.03  </td></tr>
+<tr><td>Osmium.</td><td>Os</td><td>191.7 </td></tr>
+<tr><td><i>Oxygen</i>.<a name="FNanchor_4"></a><a href="#Footnote_4"><sup>4</sup></a></td><td><i>O</i></td><td>16.  </td></tr>
+<tr><td>Palladium.</td><td>Pd</td><td>106.6 </td></tr>
+<tr><td><i>Phosphorus.</i></td><td><i>P</i></td><td>31.  </td></tr>
+<tr><td>Platinum.</td><td>Pt</td><td>195.  </td></tr>
+<tr><td><i>Potassium.</i></td><td><i>K</i></td><td>39.11 </td></tr>
+<tr><td>Rhodium.</td><td>Rh</td><td>103.5 </td></tr>
+<tr><td>Rubidium.</td><td>Rb</td><td>85.5 </td></tr>
+<tr><td>Ruthenium.</td><td>Ru</td><td>101.6 </td></tr>
+<tr><td>Samarium.</td><td>Sm</td><td>150.  </td></tr>
+<tr><td>Scandium.</td><td>Sc</td><td>44.  </td></tr>
+<tr><td>Selenium.</td><td>Se</td><td>79.  </td></tr>
+<tr><td><i>Silicon.</i></td><td><i>Si</i></td><td>28.4 </td></tr>
+<tr><td><i>Silver.</i></td><td><i>Ag</i></td><td>107.92  </td></tr>
+<tr><td><i>Sodium.</i></td><td><i>Na</i></td><td>23.05  </td></tr>
+<tr><td>Strontium.</td><td>Sr</td><td>87.6 </td></tr>
+<tr><td><i>Sulphur.</i></td><td><i>S</i></td><td>32.06  </td></tr>
+<tr><td>Tantalum.</td><td>Ta</td><td>182.6 </td></tr>
+<tr><td>Tellurium.</td><td>Te</td><td>125.  </td></tr>
+<tr><td>Terbium.</td><td>Tb</td><td>159.5 </td></tr>
+<tr><td>Thallium.</td><td>Tl</td><td>204.18  </td></tr>
+<tr><td>Thorium.</td><td>Th</td><td>232.6 </td></tr>
+<tr><td>Tin.</td><td>Sn</td><td>119.  </td></tr>
+<tr><td>Titanium.</td><td>Ti</td><td>48.  </td></tr>
+<tr><td>Tungsten.</td><td>W</td><td>184.  </td></tr>
+<tr><td>Uranium.</td><td>U</td><td>239.6 </td></tr>
+<tr><td>Vanadium.</td><td>V</td><td>51.4 </td></tr>
+<tr><td>Yterbium.</td><td>Yb</td><td>173.  </td></tr>
+<tr><td>Yttrium.</td><td>Yt</td><td>89.1 </td></tr>
+<tr><td><i>Zinc.</i></td><td><i>Zn</i></td><td>65.3 </td></tr>
+<tr><td>Zirconium.</td><td>Zr</td><td>90.6 </td></tr>
+</tbody>
+</table></div>
+
+
+<p>&mdash;<i>Am. Jour. Pharm.</i></p>
+
+<a name="Footnote_1b"></a><a href="#FNanchor_1b">[1]</a><div class="note">Has priority over niobium.</div>
+<a name="Footnote_2"></a><a href="#FNanchor_2">[2]</a><div class="note">Now split into neo-and praseo-didymium.</div>
+
+<a name="Footnote_3"></a><a href="#FNanchor_3">[3]</a><div class="note">Has priority over beryllium.</div>
+
+<a name="Footnote_4"></a><a href="#FNanchor_4">[4]</a><div class="note">Standard, or basis of the system.</div>
+
+<hr />
+
+
+<a name="tec-1"></a><h2>THE TANNING MATERIALS OF EUROPE.</h2>
+
+<p>The tanning materials of Europe are of an altogether
+different type from those of the United States.
+The population is so dense that the quantity of home
+materials produced is not nearly proportionate to the
+amount consumed, and consequently they must draw
+upon surrounding lands for their supply. The vegetation
+of these adjacent countries is of a much more
+tropical nature, and it naturally follows that the
+tanning materials are also of a different species.</p>
+
+<p>Tanning materials may be divided into two great
+classes, viz.: Physiological and pathological.</p>
+
+<h3>PHYSIOLOGICAL.</h3>
+
+<p>The first class includes those tannins which are the
+results of perfectly natural or normal growth, and a
+growth necessary to the development of vegetation,
+for instance, bark, sumac, etc., whereas the second
+class contains those which are the results of abnormal
+growth, caused by diseases, stings of insects, etc. An
+example of this is the gall. Both of these classes are
+used to a great extent in Europe, while only the first
+division is in general use in the United States. We will
+first consider the physiological tannins.</p>
+
+<p><i>Oak Bark.</i>&mdash;This material was, is, and will be for
+some time to come the main tanning material in use
+here in Europe. The advantages of the oak tannage
+are as fully appreciated here as in the United States.
+The European oak gives a light colored, firm leather,
+with good weight results, is comparatively cheap and
+of an excellent quality. The varieties are numerous,
+each country having its own kind. Those in most
+general use are:</p>
+
+<p><i>Spiegel Rinde</i> (mirror bark).&mdash;This bark is well
+distributed throughout Europe, and is peeled when the
+tree has attained a growth of from 12 to 24 years. It
+is marketed in three grades.</p>
+
+<p><i>Reitel Rinde</i>&mdash;Is obtained from the same tree as the
+spiegel rinde, but after the tree has attained a growth
+of from 25 to 40 years.</p>
+
+<p><i>Alte Pische</i> (old oak).&mdash;Obtained from the aged tree.
+It is not as valuable as the younger bark, and consequently
+brings a much lower price.</p>
+
+<p>Spiegel rinde may be judged by small warts which
+appear on the shining surface of the bark. The presence
+of a great number of these, as a rule, indicates a
+high tannin percentage.</p>
+
+<p>Bosnia has fine oak trees, the bark containing 10 to
+11 per cent. tannin.</p>
+
+<p>Bohemia has the <i>trauben eiche</i> (grape oak).</p>
+
+<p>France uses the kirmess oak, which grows in the
+south of that country and in northern Africa. Two
+grades are made, viz., root and trunk.</p>
+
+<p>Tyrol has the evergreen oak&mdash;12 to 13 per cent. tannin.</p>
+
+<p>Sardinia possesses a cork oak, which yields 13 to 14 per cent.</p>
+
+<p>White oak is found throughout Europe, yielding 10
+per cent. The price of oak bark varies a great deal.
+The assortment is much more strict than in the United
+States. In Austria it brings 4 to 5 fl., equal to $1.60 to
+$2 per kilo. (224 lb.); in Germany, 11 to 16 marks per
+100 kilos.<a name="FNanchor_1c"></a><a href="#Footnote_1c"><sup>1</sup></a></p>
+
+<p>The above mentioned varieties are all used for both
+upper and sole leather. In Germany a great deal of
+upper leather is pure oak tannage, but one seldom finds
+a pure oak tanned sole leather; it is almost always in
+combination with other tannics.</p>
+
+<p><i>Pine Bark</i>&mdash;Is well distributed and is a very
+important tanning material. It bears the same relation
+to oak bark here as does hemlock in America, but its
+effects are quite different from hemlock. The best
+Austrian sorts are those of Styria and Bohemia, but
+that of Karuthen is also of good quality. The German
+pine comes from Thuringia to a great extent. The
+countries that consume the greatest amount of pine
+bark are Austria, Germany, Russia and Italy. The
+tannin contained varies from 5 to 16 per cent. Its
+use is almost wholly confined to the handlers, as its
+weight returns are not so satisfactory as oak or valonia.
+In case it should be used for layers it is always in
+combination with some better weight-giving tannic. For
+upper leather its use is limited.</p>
+
+<p>The bark is always peeled from the felled tree, and
+often the woodman accepts the bark in part payment
+for his labor; he then sells the bark to the tanner or
+agents who go about the country collecting bark. It
+is generally very nicely cleaned. I would here like to
+correct a mistake which tanners often make in their
+estimations of the value of barks. A tanner usually
+buys the bark of southern-grown trees in preference to
+that of trees grown in northern countries, as it is a
+common idea that southern vegetation contains more
+tannin than that of the north. This is a fallacy, as has
+not only been proved by careful analyses, but may
+also be found to be an incorrect conclusion after a
+moments' thought. Those trees which flourish in
+southern countries grow very rapidly, and as tannin is
+necessary to the development of leaf structure, etc., it
+is absorbed to a greater extent than is the case with
+the slower-growing tree of the north. The tannin
+contained in the sap does not increase in the same ratio
+as does the rapid growth, and it follows that the remainder
+in the bark is less than in the tree of slower growth.</p>
+
+<p><i>Birch Bark</i>&mdash;Is at home in Russia, Norway, and
+Sweden. It is used for both upper and sole leather,
+but seldom alone. The bark is usually peeled from
+the full grown tree, and contains 4 to 9 per cent.
+tannin.</p>
+
+<p><i>Willow Bark</i>&mdash;May also be found in the above
+mentioned countries and also in Germany. This material
+is used for both upper and sole leather, and contains
+6 to 9 per cent. tannin. It is a very delicate material
+to use, as its tannin decomposes rapidly.</p>
+
+<p><i>Erlen Rinde</i>&mdash;Is also a native of Germany, but is
+not used to any great extent. The same may be said of
+the larch, although this variety is also to be met with
+in Russia.</p>
+
+<p><i>Mimosa Bark</i>&mdash;Is obtained from the acacia of
+Australia. It is a favorite in England. The varieties are
+as follows: Gold wattle, silver wattle (blackwood,
+lightwood), black wattle, green wattle. The gold wattle
+is a native of Victoria. Its cultivation was tried as
+an experiment in Algeria and met with some success.
+
+The trees are always grown from seeds. These seeds
+are laid in warm water for a few hours before sowing.
+The acacia may be peeled at eight years' growth and
+carries seeds. The Tasmania bark is very good; that
+from Adelaide likewise good.</p>
+
+<p>Sydney does not produce so good an article, but
+Queensland better. The bark is marketed in the stick,
+ground or chopped.</p>
+
+<p>Madagascar and the Reunion Islands have also a
+mimosa bark.</p>
+
+<p>The mimosa barks give a reddish colored leather,
+pump well and contain a high tannin percentage, 10 to
+35 per cent.</p>
+
+<p>Now we will consider the fruit tanning materials.</p>
+
+<p>Valonia may truly be called one of the most generally
+used tanning agents at present employed in Europe.
+All countries consume it more or less. Valonia was
+first used in England about the beginning of this century.
+A few years later Germany began using it, and
+still later Austria introduced it. It is the fruit of the
+oak tree and is obtainable in Asia Minor and the adjacent
+islands. In form it resembles the American
+acorn, but in size it nearly trebles it. The fruit may
+be divided into two parts, namely, the cup and acorn,
+and the cup again divided into trillor and inner cup.
+The acorn only contains 10 per cent. tannin, whereas
+the cup contains from 25 to 40 per cent.</p>
+
+<p>The percentage depends altogether upon the time of
+harvesting and the place of growth. The best valonia
+is derived from Smyrna, and is naturally the highest
+priced article. Valonia is worth from 22 to 28 florins
+($9 to $11) per 100 kilos. (224 pounds) at present. The
+other provinces and islands from which it is obtainable
+are Demergick, Govalia, Idem, Ivalzick, Troy (this is
+the best); Metelino Island, the vicinity of Smyrna.
+The material sold in three grades&mdash;prime, mazzano;
+seconds, una aqua; thirds, skart.</p>
+
+<p>The product of Smyrna generally averages:</p>
+
+<div class="ctr"><table summary="product of smyrna" border="0" cellspacing="5">
+<tr><td> </td><td>Tons.</td><td>Price.</td></tr>
+<tr><td>Prime.</td><td>2,000 to  3,000</td><td>28 florins.</td></tr>
+<tr><td>Seconds.</td><td>5,000 to 10,000</td><td>25 florins.</td></tr>
+<tr><td>Thirds.</td><td>20,000 to 30,000</td><td> 22 florins.</td></tr>
+</table></div>
+
+<p>The <i>Metilino</i> valonia is a product of a neighboring
+island, and is a very good article. It may be easily
+distinguished by its thin cup. It is harvested in September.</p>
+
+<p>The <i>Candia</i> valonia is nearly as long as it is wide, in
+contrast to the Smyrna, which is much wider than long.
+The recent harvest showed a return of 800 to 1,000 tons,
+but no assortment is made. A grade called the Erstlige
+is sold, this being the first which has fallen to the
+ground before maturing.</p>
+
+<p>A peculiarity of the valonia is that it often strikes
+out a sort of sugar sweat, which gives the cup a less
+attractive appearance, but denotes the presence of large
+quantities of tannin.</p>
+
+<p>Valonia is used almost wholly for sole leather, either
+alone or in combination with pine or oak bark or
+knoppern and myrabolams. The union of valonia and
+knoppern is that in most general use. Valonia gives the
+leather a yellowish appearance, as it deposits a great
+deal of yellow bloom. The leather is very firm and
+of good wearing qualities. The weight results are
+also excellent, as will be seen below. To sole leather
+there are usually given from one to three layers of
+valonia. The demand for valonia is increasing more
+and more every year, and the present outlook does not
+indicate any relaxation of its popularity. Its use for
+upper leather is very limited.</p>
+
+<p>Myrabolams are mainly used in England and Austria,
+and give a nice light-colored leather, both upper and
+sole, although rarely used alone. Their main use is for
+dyeing purposes. They are indigenous to the East
+Indies.</p>
+
+<p>Sumac is so well known that treating of it is superfluous.
+Its use is very extensive, and it is a general
+favorite for light, fine leather, which is mostly used
+for colors.</p>
+
+<p><i>Gambier</i>&mdash;Is in general use in England and to some
+extent in Germany.</p>
+
+<p><i>Catechu</i>.&mdash;Obtained from India, resembles gambier
+greatly. Its use is almost wholly confined to England.
+It is also consumed by the silk manufacturers in preference
+to gambier, for weighting purposes.</p>
+
+<h3>PATHOLOGICAL.</h3>
+
+<p>We now leave the physiological class and take up
+those tanning materials included in the pathological
+class, or those of abnormal growth.</p>
+
+<p><i>Galls</i>.&mdash;These are not consumed to any great extent
+at the present period, but formerly they were used
+quite extensively. The galls are found upon the leaves
+of the oak or sumac, etc. The direct cause of their
+growth is that a certain wasp (cynips galles) stings into
+the leaf and after depositing its egg, flies away. The
+egg develops into a larva and then into a full-fledged
+wasp, boring its way out of the gall which has served
+as a protection and nourisher. This accounts for the
+hole noticed in almost every gall. The different varieties
+include Aleppo. It is found upon the same trees as the
+valonia and contains 60 to 75 per cent. tannin; Istrian
+galls, 32 per cent. tannin; Persian, 28 to 29 per cent.
+tannin. Chinese galls, giving 80 to 82 per cent. tannin,
+are the results of the sting of a louse, and make a very
+light-colored leather. The dyers also use this material
+for coloring.</p>
+
+<p><i>Knoppern</i>&mdash;Belongs to the family of galls, and is a
+most important factor of commerce in Austria. The
+knopper is generally found on the acorn or leaf of the
+oak tree. The greatest quantity is derived from the
+steel oak of Hungary. The tannin contained varies
+from 27 to 33 per cent. Knoppern are not being used
+so much now as formerly, and consequently the amount
+harvested lessens from year to year. Its main use was
+and is in combination with valonia as layers for sole
+leather. Valonia gives better weight results than
+knoppern, and is replacing knoppern more and more
+every year. The combination of knoppern, valonia
+and myrabolams is also quite popular, and gives
+good results. Knoppern are seldom used alone, being
+generally combined with some other tannin. Austria
+is almost the only consumer at present, but Germany
+used it extensively formerly.</p>
+
+<p><i>Bark and Wood Extracts</i>&mdash;Are becoming general
+favorites throughout Europe, partly because of their
+weight-giving qualities and partly as the transportation
+costs so little; they can be used to strengthen weak
+bark liquors.</p>
+
+
+<p><i>Oak Extracts</i>&mdash;Are well liked, both wood and bark,
+and are used extensively. Slavonia furnishes a great
+deal of it.</p>
+
+<p><i>Chestnut Oak Wood Extract</i>&mdash;Is manufactured in
+quantities, and easily finds purchasers.</p>
+
+<p><i>Pine Bark Extract</i>&mdash;Is also consumed in goodly
+amounts.</p>
+
+<p><i>Quebracho Wood Extract</i>.&mdash;The wood is shipped from
+Brazil to Hamburg and other ports, and the tannin
+extracted there. Hamburg furnishes quantities
+of it.</p>
+
+<p><i>Hemlock Extract</i>&mdash;Is used in Russia, and seems to
+have taken a hold on the shoe buyers' fancies, as they
+now make imitations of it in color. The hemlock that
+is consumed is imported from America.</p>
+
+<p>As most leather is sold by weight in Europe, the
+leather manufacturers aim to obtain as good weight
+results as possible, and often, I am sorry to say, do so
+at the sacrifice of quality. This is common to both
+upper and sole leather. Sole leather is nine times out
+of ten given false weight by forcing entirely foreign
+substances into the leather, such as glucose, barium
+chloride, magnesium chloride, resins, etc. Glucose and
+resin are also used for weighting upper leather. Leather
+is also weighted with extracts by overtanning. Leather
+buyers have become very wary of late and do not purchase
+large quantities before an analysis is made of a
+fair sample.</p>
+
+<p>One more word before I close. The governments and
+private individuals in Europe cultivate and raise trees
+for both lumber and bark purposes. The forests are
+excellently cared for by efficient foresters, and the result
+is that the tanners obtain much cleaner and better
+bark, and of a very even quality. Would it not be a
+good idea if some individual, who would certainly earn
+the everlasting gratefulness of the tanners, would look
+into this matter, and see that not only the lumber side
+of our forest cultivation is not neglected, but that the
+bark also is preserved and cared for? Of course, we
+can obtain all the bark necessary at present and for
+some time to come, but the time will come when we
+shall certainly regret not having taken these steps, if
+the lumbermen and bark peelers go on devastating
+magnificent forests. Below will be found a table of
+weight results. Sole leather tanned with these materials
+gives for every 100 lb. green hide the following
+quantities of finished leather:</p>
+
+<div class="ctr"><table summary="Tannic Tanned Weights" border="0" cellspacing="5">
+<tr>
+<td> </td>
+<td> lb. </td>
+</tr>
+<tr><td>Oak bark</td><td>48 to 54</td></tr>
+<tr><td>Oak extract</td><td>55 to 56</td></tr>
+<tr><td>Pine bark </td><td>44 to 46</td></tr>
+<tr><td>Pine extract</td><td> 48 to 50</td></tr>
+<tr><td>Willow </td><td>45 to 46</td></tr>
+<tr><td>Birch bark and oak extract</td><td>49 to 51</td></tr>
+<tr><td>Quebracho wood and extract </td><td>48 to 49</td></tr>
+<tr><td>Valonia </td><td>52 to 56</td></tr>
+<tr><td>Knoppern </td><td>51 to 53</td></tr>
+<tr><td>Myrabolams </td><td>50</td></tr>
+<tr><td>Knoppern, myrabolams and valonia</td><td>52 to 53</td></tr>
+<tr><td>Hemloc</td><td>55</td></tr>
+</table></div>
+
+<p>Specification of tanning materials used in different
+countries:</p>
+
+<pre>
+   <i>France.</i>
+      Oak bark (kirmess).
+      Sumac.
+      Chestnut wood extract.
+      Quebracho "     "
+      Some gambier.
+
+   <i>Italy.</i>
+      Oak bark.
+      Pine "
+      Sumac.
+      Valonia.
+
+   <i>England.</i>
+      Oak bark.
+      Divi divi.
+      Myrabolams.
+      Valonia.
+      Mimosa.
+      Extracts { Oak bark and wood hemlock.
+      Gambier.
+      Cutch.
+
+   <i>Germany and Austria.</i>
+      Oak bark.
+      Pine "
+      Willow bark.
+      Valonia.
+      Knoppern.
+      Myrabolams.
+               { Oak bark and wood.
+      Extracts { Pine bark and wood.
+
+   <i>Russia.</i>
+      Birch bark.
+      Willow "
+      Oak    "
+      Pine   "
+      Hemlock extract.
+
+
+   <i>Norway and Sweden.</i>
+      Birch bark.
+      Willow "
+      Oak    "
+
+</pre>
+
+<div style="margin-left: 10em; ">WALTER J. SALOMON.<br/><br />
+&mdash;<i>Shoe and Leather Reporter.</i></div>
+
+<a name="Footnote_1c"></a><a href="#FNanchor_1c">[1]</a><div class="note">
+In the principal districts in America, removed from the cities,
+the price of oak bark is about $4 to $6 per cord or per ton
+of 2,240 lb. The hemlock bark, which gives a sole leather just as
+thoroughly tanned, but of a darker and reddish color, costs the
+larger tanners from $3 to $4 a cord.</div>
+
+<hr />
+
+<a name="chem-1"></a><h2>AN APPARATUS FOR HEATING SUBSTANCES
+IN GLASS TUBES UNDER PRESSURE.<a name="FNanchor_1d"></a><a href="#Footnote_1d"><sup>1</sup></a></h2>
+
+<h4>By H. PEMBERTON, Jr.</h4>
+
+<p>Chemists who do not happen to have in their laboratories
+oil or air baths for heating closed tubes can
+make an air bath at short notice from materials furnished
+by all dealers in steam fittings.</p>
+
+<p><i>Order</i>:</p>
+
+<p>(1) One four-inch wrought iron pipe, eighteen inches
+out to out, with usual thread on each end. At about
+nine inches from either end this pipe is drilled and tapped
+for a one-inch nipple, in such a manner that a pipe
+introduced would pass, not on a line with the radius,
+but about half way between the axis of the four-inch
+pipe and its walls; in other words, it would be on a
+line with a chord of the circle.</p>
+
+<p>(2) One one-inch wrought iron nipple, two inches
+long, one-inch thread on one end.</p>
+
+<p>(3) Two four-inch malleable iron caps, drilled and
+tapped for a one-inch pipe.</p>
+
+<p>(4) One one-inch wrought iron pipe, twenty-four
+inches out to out, with a three-inch straight thread
+on each end.</p>
+
+<p>(5) Two one-inch iron caps. A hole, one-eighth of an
+inch in diameter, is drilled in the end of one of these
+caps.</p>
+
+<p>The above order can be given <i>literatim</i>, and will be
+understood by the dealer, who will furnish, at a trifling
+cost, the materials, cut and tapped as ordered.</p>
+
+<p>
+<img src="images/16-fig12.png" align="left" alt="FIG. 1." title="">
+Fig. 1 shows how the whole is put together. The
+numbers on the figure correspond also to the numbers
+of the paragraphs of the order as given above.</p>
+
+<p>Fig. 2 is an end section. A cork is inserted in 2 and
+through it a thermometer, the bulb of which is on a
+level with the interior pipe. The whole is supported
+on a few bricks at either end, and is kept steady and
+in place by a couple of weights or half bricks. It is
+heated by one or two Bunsen burners, according to the
+temperature desired.&mdash;<i>Jour. Fr. Institute</i>.</p>
+
+<a name="Footnote_1d"></a><a href="#FNanchor_1d">[1]</a><div class="note">Read at the meeting of the Chemical Section of the Franklin Institute
+held March 17, 1891.</div>
+
+<hr />
+
+<a name="chem-3"></a><h2>TESTING CEMENT.</h2>
+
+<p>An improved method of testing Portland cement has
+been adopted by M. Deval, Chief Superintendent of
+Bridges and Roads, who has charge, under M. Saele,
+of the Public Works Laboratory of the City of Paris.
+The principal difference in M. Deval's method consists
+in the use of hot water for the period of hardening. The
+briquettes are made in the usual way, and of the ordinary
+size; and the cement to be tested is gauged with
+three times its weight of normal sand, and the smallest
+quantity of water possible. After preparation, the
+briquettes are allowed to harden in air for a period
+ranging from 24 hours for Portland cement to 30 days
+for certain slow-setting hydraulic limes. After this
+period, the samples are immersed in water kept at a
+temperature of 80° C., in which they remain for from
+two to seven days. The briquettes are then broken in
+the ordinary way. After careful comparisons of many
+varieties of cement hardened hot and cold, M. Deval
+finds that cold tests are fallacious, inasmuch as they
+may fail to detect bad material. Portland cement of
+good quality will not only stand water at 80° C., but
+will attain in seven days about the same strength as is
+reached in the cold after 28 days. The hot test therefore
+saves time. The hot test is an unfailing proof for
+free lime; cements containing this constituent betraying
+weakness, and cracking, swelling, and disintegrating
+in a very significant manner. This last result
+is regarded as a valuable quality of the new method of
+testing cement, the general effect of which appears to
+be to enhance the test value of really good cements,
+while depreciating those of an inferior character.</p>
+
+<hr />
+
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+
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+
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+
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+
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+
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+
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+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+803, May 23, 1891, by Various
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+The Project Gutenberg EBook of Scientific American Supplement, No. 803,
+May 23, 1891, 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: Scientific American Supplement, No. 803, May 23, 1891
+
+Author: Various
+
+Release Date: September 3, 2004 [EBook #13358]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Don Kretz, Juliet Sutherland, Victoria Woosley and the
+Online Distributed Proofreading Team.
+
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 803
+
+
+
+
+NEW YORK, May 23, 1891
+
+Scientific American Supplement. Vol. XXXI., No. 803.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+
+         *       *       *       *       *
+
+
+
+
+TABLE OF CONTENTS.
+
+
+I.    ASTRONOMY.--The Great Equatorial of the Paris Observatory.--
+      The new telescope recently put in use in Paris.--Description of
+      the instrument and of its effects.--3 illustrations
+
+II.   CHEMISTRY.--An Apparatus for Heating Substances in Glass
+      Tubes under Pressure.--By H. PEMBERTON, Jr.--A simple apparatus
+      for effecting this purpose, avoiding risk of personal injury.--
+      2 illustrations
+
+      Table of Atomic Weights.--A revised table of atomic weights,
+      giving the results of the last determinations, and designed for
+      every-day use
+
+      Testing Cement.--A laboratory process for testing Portland cement
+
+III.  CIVIL ENGINEERING.--The Compressed Air System of Paris.
+      --An elaborate review of this great installation for the transmission
+      of power.--The new compressed air station, with full details
+      of performances of apparatus, etc.--10 illustrations
+
+IV.   ENTOMOLOGY.--Report on Insects.--Continuation of this report
+      on noxious insects.--Their habits and how to cope with them.
+      --18 illustrations
+
+V.    FLORICULTURE.--Lily of the Valley.--Practical notes on the
+      cultivation of this popular flower.--How to raise it and force the
+      growth
+
+VI.   MATHEMATICS.--The Conic Sections.--By Prof. C.W.
+      MACCORD.--Examination of the four conic sections with a general
+      definition applicable to all.--6 illustrations
+
+VII.  MECHANICAL ENGINEERING.--The Builders of the Steam
+      Engine--The Founders of Modern Industries and Nations.--By Dr.
+      R.H. THURSTON.--Prof. Thurston's address before the Centennial
+      Celebration of the American Patent System at Washington,
+      D.C.--The early history of the steam engine and its present position
+      in the world
+
+VIII. MISCELLANEOUS.--The Breeds of Dogs.--Popular description
+      of the different breeds of dogs most affected by amateurs.--6
+      illustrations
+
+IX.   NAVAL ENGINEERING.--Modern Armor.--By F.R. BRAINARD.--The
+      development of modern ship armor, from laminated
+      sandwiched and compound types to the present solid armor.--9
+      illustrations
+
+X.    PISCICULTURE.--Restocking the Seine with Fish.--The introduction
+      of 40,000 fry of California trout and salmon, designed to restock
+      the Seine, depopulated of fish by explosions of dynamite
+      used in breaking up the ice.--1 illustration
+
+XI.   RAILWAY ENGINEERING.--Improved Hand Car.--A novelty
+      in the construction of hand cars, avoiding the production of a
+      dead center.--1 illustration
+
+XII.  TECHNOLOGY.--The Tanning Materials of Europe.--The natural
+      tanning materials and pathological or abnormal growth tanning
+      materials described and classified, with relative power
+
+
+         *       *       *       *       *
+
+
+
+
+THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.
+
+
+The great instrument which has just completed the installation of our
+national observatory is constructed upon the same principle as the
+elbowed equatorial, 11 in. in diameter, established in 1882, according
+to the ingenious arrangement devised as long ago as 1872, by Mr.
+Loewy, assistant director of the Paris Observatory.
+
+We shall here recall the fact that the elbowed equatorial consists of
+two parts joined at right angles. One of these is directed according
+to the axis of the world, and is capable of revolving around its own
+axis, and the other, which is at right angles to it, is capable of
+describing around the first a plane representing the celestial
+equator. At the apex of the right angle there is a plane mirror of
+silvered glass inclined at an angle of 45 deg. with respect to the
+optical axis, and which sends toward the ocular the image coming from
+the objective and already reflected by another and similar plane
+mirror. The objective and this second mirror (which is inclined at an
+angle of 45 deg.) are placed at the extremity of the external part of
+the tube, and form part of a cube, movable around the axis of the
+instrument at right angles with the axis of the world. The diagram in
+Fig. 3 will allow the course of a luminous ray coming from space to be
+easily understood. The image of the star, A, toward which the
+instrument is directed, traverses the objective, B C, is reflected
+first from the mirror, B D, and next from the central mirror, E F, and
+finally reaches O, at the ocular where the observer is stationed.
+
+This new equatorial differs from the first model by its much larger
+dimensions and its extremely remarkable mechanical improvements. The
+optical part, which is admirably elaborated, consists of a large
+astronomical objective 24 in. in diameter, and of a photographic
+objective of the same aperture, capable of being substituted, one for
+the other, according to the nature of the work that it is desired to
+accomplish by the aid of this colossal telescope, the total length of
+which is 59 ft. The two plane mirrors which complete the optical
+system have, respectively, diameters of 34 in. and 29 in. These two
+magnificent objectives and the two mirrors were constructed by the
+Brothers Henry, whose double reputation as astronomers and opticians
+is so universally established. The mechanical part is the successful
+work of Mr. Gautier, who has looked after every detail with the
+greatest care, and has thus realized a true _chef d'oeuvre_. The
+colossal instrument, the total weight of which is 26,400 lb., is
+maneuvered by hand with the greatest ease. A clockwork movement, due
+to the same able manufacturer, is capable, besides, of moving the
+instrument with all the precision desirable, and of permitting it to
+follow the stars in their travel across the heavens. A star appearing
+in the horizon can thus be observed from its rising to its setting.
+The astronomer, his eye at the ocular, is always conveniently seated
+at the same place, observing the distant worlds, rendered immovable,
+so to speak, in the field of the instrument. For stars which, like the
+moon and the planets, have a course different from the diurnal motion,
+it is possible to modify the running of the clockwork, so that they
+can thus be as easily followed as in the preceding case. Fig. 1 gives
+a general view of the new installation, for which it became necessary
+to build a special edifice 65 ft. in height on the ground south of the
+observatory bordering on the Arago Boulevard. A large movable
+structure serves for covering the external part of the instrument.
+This structure rests on rails, upon which it slides toward the south
+when it is desired to make observations. It will be seen from the
+figure how the principal axis of the instrument rests upon the two
+masonry pillars, one of which is 49 ft. and the other 13 ft. in
+height.
+
+[Illustration: FIG 1.--THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY.]
+
+The total cost of the pavilion, rolling structure, and instrument
+(including the two objectives) will amount to about $80,000 after the
+new equatorial has been provided with the scientific apparatus that
+necessarily have to accompany it for the various and numerous
+applications to which the use of it will give rise.
+
+[Illustration: FIG 2.--OCULAR OF THE GREAT EQUATORIAL.]
+
+Fig. 2 shows us the room in the observatory in which the astronomer,
+seated in his chair, is completely protected against the inclemencies
+of the weather. Here, with his eye applied to the ocular, he can,
+without changing position (owing to all the handles that act at his
+will upon the many transmissions necessary for the maneuvering),
+direct his instrument unaided toward every point of the heavens with
+wonderful sureness and precision. The observer has before him on the
+same plane two divided circles, one of which gives the right
+ascensions and the other the declinations, and which he consults at
+each observation for the exact orientation of the equatorial.
+
+[Illustration: FIG. 3.--DIAGRAM SHOWING THE COURSE OF A LUMINOUS RAY
+IN THE GREAT EQUATORIAL.]
+
+All the readings are done by the aid of electric lamps of very small
+dimensions, supplied by accumulators, and which are lighted at will.
+Each of these lamps is of one candle power; two of them are designed
+for the reading of the two circles of right ascension and of
+declination; a third serves for the reading of the position circle of
+the micrometer; two others are employed for the reading of the drums
+fixed upon the micrometric screws; four others serve for rendering the
+spider threads of the reticule brilliant upon a black ground; and
+still another serves for illuminating the field of the instrument
+where the same threads remain black upon a luminous ground. The
+currents that supply these lamps are brought over two different
+circuits, in which are interposed rheostats that permit of graduating
+the intensity of the light at will.
+
+Since the installation of the first model of an elbowed equatorial of
+11 in. aperture, in 1882, at the Paris Observatory, the numerous and
+indisputable advantages of this sort of instrument have led a certain
+number of observatories to have similar, but larger, instruments
+constructed. In France, the observatories of Alger, Besancon, and
+Lyons have telescopes of this kind, the objectives of which have
+diameters of from 12 in. to 13 in., and which have been used for
+several years past in equatorial observations of all kinds. The Vienna
+Observatory has for the last two years been using an instrument of
+this kind whose objective has an aperture of 15 inches. Another
+equatorial of the same kind, of 16 in. aperture, is now in course of
+construction for the Nice Observatory, where it will be especially
+employed as a seeker of exceptional power--a role to which this kind
+of instrument lends itself admirably. The optical part of all these
+instruments was furnished by the Messrs. Henry, and the mechanical
+part by Mr. Gautier.
+
+The largest elbowed equatorial is, therefore, that of the Paris
+Observatory. Its optical power, moreover, corresponds perfectly to its
+huge dimensions. The experimental observations which have already been
+made with it fully justify the hopes that we had a right to found upon
+the professional skill of the eminent artists to whom we owe this
+colossal instrument. The images of the stars were given with the
+greatest sharpness, and it was possible to study the details of the
+surface of the moon and other planets, and several star clusters, in
+all their peculiarities, in the most remarkable manner.
+
+When it shall become possible to make use of this equatorial for
+celestial photography, there is no doubt that we shall obtain the most
+important results. As regards the moon, in particular, the
+photographing of which has already made so great progress, its direct
+image at the focus of the large 24 in. photographic objective will
+have a diameter of 11 in., and, being magnified, will be capable of
+giving images of more than 3 ft. in diameter.--_La Nature_.
+
+       *       *       *       *       *
+
+
+
+
+LILY OF THE VALLEY.
+
+
+There is no flower more truly and universally popular than the lily of
+the valley. What can be more delicious and refreshing than the scent
+of its fragrant flowers? What other plant can equal in spring the
+attractiveness of its pillars of pure white bells half hidden in their
+beautiful foliage? There are few gardens without a bed of lily of the
+valley, but too often the place chosen for it is some dark corner
+where nothing else would be expected to grow, but it is supposed as a
+matter of course that "it will do for a lily bed." The consequence is
+that although these lilies are very easy things to cultivate, as
+indeed they ought to be, seeing that they grow wild in the woods of
+this and other countries, yet one hears so often from those who take
+only a slight interest in practical gardening, "I have a lily bed, but
+I scarcely ever get any lilies." Wild lilies are hardly worth the
+trouble of gathering, they are so thin and poor; it is interesting to
+find a plant so beautiful and precious in the garden growing wild in
+the woods, but beyond that the flowers themselves are worth but very
+little. This at once tells us an evident fact about the lily of the
+valley, viz., that it does require cultivation. It is not a thing to
+be left alone in a dark and dreary corner to take care of itself
+anyhow year after year. People who treat it so deserve to be
+disappointed when in May they go to the lily bed and find plenty of
+leaves, but no flowers, or, if any, a few poor, weak attempts at
+producing blossoms, which ought to be so beautiful and fragrant.
+
+One great advantage of this lovely spring flower is that it can be so
+readily and easily forced. Gardeners in large places usually spend
+several pounds in the purchase of crowns and clumps of the lily of the
+valley, which they either import direct from foreign nurserymen or
+else procure from their own dealer in such things, who imports his
+lilies in large quantities from abroad. But we may well ask, Have
+foreign gardeners found out some great secret in the cultivation of
+this plant? Or is their climate more suitable for it? Or their soil
+adapted to growing it and getting it into splendid condition for
+forcing? It is impossible that the conditions for growing large and
+fine heads of this lily can be in any way better in Berlin or
+elsewhere than they are in our own land, unless greater heat in summer
+than we experience in England is necessary for ripening the growths in
+autumn.
+
+There is another question certainly as to varieties; one variety may
+be superior to another, but surely if so it is only on the principle
+of the survival of the fittest, that is to say, by carefully working
+on the finest forms only and propagating from them, a strong and
+vigorous stock may be the result, and this stock may be dignified with
+a special name. For my own part what I want is to have a great
+abundance of lily of the valley from February till the out-door season
+is over. To do this with imported clumps would, of course, be most
+costly, and far beyond what any person ought to spend on mere flowers.
+Though it must be remembered that it is an immense advantage to the
+parish priest to be able to take bright and sweet flowers to the
+bedside of the sick, or to gratify the weary spirit of a confirmed
+invalid, confined through all the lovely spring time to the narrow
+limits of a dull room, with the fragrant flowers of the lily of the
+valley. I determined, therefore, that I would have an abundance of
+early lilies, and that they should not be costly, but simply produced
+at about the same expense as any other flowers, and I have been very
+successful in accomplishing this by very simple means. First of all,
+it is necessary to have the means of forcing, that is to say the
+required heat, which in my case is obtained from an early vinery. I
+have seen lilies forced by pushing the clumps in under the material
+for making a hot bed for early cucumbers, the clumps being drawn out,
+of course, as soon as the flowers had made a good start. They have
+then to be carefully and very gradually exposed to full light, but
+often, although fine heads of bloom may be produced in this way, the
+leaves will be few and poor.
+
+My method is simply this: In the kitchen garden there is the old
+original bed of lilies of the valley in a corner certainly, but not a
+dark corner. This is the reservoir, as were, from whence the regular
+supply of heads for special cultivation is taken. This large bed is
+not neglected and left alone to take care of itself, but carefully
+manured with leaf mould and peat moss manure from the stable every
+year. Especially the vacant places made by taking out the heads for
+cultivation are thus filled up.
+
+Then under the east wall another piece of ground is laid out and
+divided into four plots. When I first began to prepare for forcing I
+waited four years, and had one plot planted with divided heads each
+year. Clumps are taken up from the reserve bed and then shaken out and
+the heads separated, each with its little bunch of fibrous roots. They
+are then carefully planted in one of the plots about 4 in. or 5 in.
+apart, the ground having previously been made as light and rich as
+possible with plenty of leaf mould. I think the best time for doing
+this is in autumn, after the leaves have turned yellow and have rotted
+away; but frequently the operation has been delayed till spring,
+without much difference in the result.
+
+Asparagus is usually transplanted in spring, and there is a wonderful
+affinity between the two plants, which, of course, belong to the same
+order. It was a long time to wait--four years--but I felt there was no
+use in being in too great a hurry, and every year the plants
+manifestly improved, and the buds swelled up nicely and looked more
+plump each winter when the leaves were gone. It must be remembered
+also that a nice crop of flowers could be gathered each year. When the
+fourth year came, the first plot was divided up into squares about 2
+ft. each way, and taken up before any hard frost or snow had made
+their appearance, and put away on the floor of an unused stable. From
+the stable they are removed as required in the squares to the vinery,
+where they grow beautifully, not sending up merely fine heads of bloom
+without a vestige of leaf, but growing as they would in spring out of
+doors with a mass of foliage, among which one has to search for the
+spikes of flower, so precious for all sorts of purposes at that early
+season of the year.
+
+The spikes produced in this way do not equal in thickness and
+substance of petal the flowers which come from more carefully prepared
+clumps imported from Berlin, but they are fine and strong, and above
+all most abundant. I can not only supply the house and small vases for
+the church, but also send away boxes of the flowers to friends at a
+distance, besides the many gifts which can be made to those who are
+ill or invalids. Few gifts at such a time are more acceptable than a
+fragrant nosegay of lily of the valley. In order to keep the supply of
+prepared roots ready year after year, a plot of ground has only to be
+planted each autumn, so that in the rotation of years it may be ready
+for forcing when its turn shall come.
+
+As the season advances, as every one knows who has attempted to force
+the lily of the valley, much less time is taken in bringing the
+flowers to perfection under precisely the same circumstances as those
+in which the first sods are forced. In February or earlier the buds
+are more unwilling to start; there seems to be a natural repugnance
+against being so soon forced out of the winter's sleep and rest. But
+when the flowers do come, they are nearly as fine and their leaves are
+quite as abundant in this way of forcing as from the pieces introduced
+much later into heat. It would be easy to preserve the squares after
+all the flowers are gathered, but I found that they would not, like
+strawberries, kindly furnish forth another crop later on in the year,
+and, therefore, mine are flung away; and I have often pitied the
+tender leaves in the frost and snow after their short sojourn in the
+hot climate of the vinery. But the reserve bed will always supply an
+ample quantity of fresh heads, and it is best to take the new plants
+for preparation in the kitchen garden from this reserve bed.
+
+This very simple method of forcing lilies of the valley is within the
+reach of any one who has even a small garden and a warm house, and
+these two things are becoming more and more common among us every
+day.--_A Gloucestershire Parson, in The Garden_.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12820.]
+
+
+
+
+REPORT ON INSECTS.
+
+THE ONION MAGGOT.
+
+_Phorbia ceparum_ (Meig.)
+
+
+Early in June a somewhat hairy fly, Fig. 9, may be seen flying about,
+and depositing its eggs on the leaves of the young onion plants, near
+the roots, Fig. 10.
+
+[Illustration: FIG. 9.]
+
+Dr. Fitch describes this fly as follows: "It has a considerable
+resemblance to the common house fly, though when the two are placed
+side by side, this is observed as being more slender in its form. The
+two sexes are readily distinguished from each other by the eyes, which
+in the males are close together, and so large as to occupy almost the
+whole surface of the head, while in the females they are widely
+separated from each other. These flies are of an ash gray color, with
+the head silvery, and a rusty black stripe between the eyes, forked at
+its hind end. And this species is particularly distinguished by having
+a row of black spots along the middle of the abdomen or hind body,
+which sometimes run into each other, and then forming a continuous
+stripe.
+
+"This row of spots is quite distinct in the male, but in the female is
+very faint, or is often wholly imperceptible. This fly measured 0.22
+to 0.25 inch in length, the females being usually rather larger than
+the males." The eggs are white, smooth, somewhat oval in outline, and
+about one twenty-fifth of an inch in length. Usually not more than
+half a dozen are laid on a single plant, and the young maggot burrows
+downward within the sheath, leaving a streak of pale green to indicate
+its path, and making its way into the root, devours all except the
+outer skin.
+
+[Illustration: FIG. 10.]
+
+The maggots reach their full growth in about two weeks, when they are
+about one-third of an inch long, white and glossy, tapering from the
+posterior end to the head, which is armed with a pair of black,
+hook-like jaws. The opposite end is cut off obliquely and has eight
+tooth-like projections around the edge, and a pair of small brown
+tubercles near the middle. Fig. 11 shows the eggs, larva, and pupa,
+natural size and enlarged.
+
+[Illustration: FIG. 11.]
+
+They usually leave the onions and transform to pupae within the ground.
+The form of the pupa does not differ very much from the maggot, but
+the skin has hardened and changed to a chestnut brown color, and they
+remain in this stage about two weeks in the summer, when the perfect
+flies emerge. There are successive broods during the season, and the
+winter is passed in the pupa stage.
+
+The following remedies have been suggested:
+
+Scattering dry, unleached wood ashes over the plants as soon as they
+are up, while they are wet with dew, and continuing this as often as
+once a week through the month of June, is said to prevent the deposit
+of eggs on the plants.
+
+Planting the onions in a new place as remote as possible from where
+they were grown the previous year has been found useful, as the flies
+are not supposed to migrate very far.
+
+Pulverized gas lime scattered along between the rows has been useful
+in keeping the flies away.
+
+Watering with liquid from pig pens collected in a tank provided for
+the purpose, was found by Miss Ormerod to be a better preventive than
+the gas lime.
+
+When the onions have been attacked and show it by wilting and changing
+color, they should either be taken up with a trowel and burned, or
+else a little diluted carbolic acid, or kerosene oil, should be
+dropped on the infested plants to run down them and destroy the
+maggots in the roots and in the soil around them.
+
+Instead of sowing onion seed in rows, they should be grown in hills,
+so that the maggots, which are footless, cannot make their way from
+one hill to another.
+
+
+THE CABBAGE BUTTERFLY.
+
+_Pieris rapae_ (Linn.)
+
+
+In the New England States there are three broods of this insect in a
+year, according to Mr. Scudder, the butterflies being on the wing in
+May, July, and September; but as the time of the emergence varies, we
+see them on the wing continuously through the season.
+
+[Illustration: FIG. 12.]
+
+The expanded wings, Fig. 12, male, measure about two inches, are white
+above, with the base dusky. Both sexes have the apex black and a black
+spot a little beyond the middle, and the female, Fig. 13, has another
+spot below this. The under side of the fore wings is white, yellowish
+toward the apex, and with two black spots in both sexes corresponding
+to those on the upper side of the female. A little beyond the middle
+of the costa, on the hind wings, is an irregular black spot on the
+upper surface, while the under surface is pale lemon yellow without
+marks, but sprinkled more or less with dark atoms. The body is black
+above and white beneath.
+
+[Illustration: FIG. 13.]
+
+The caterpillars of this insect feed on the leaves of cabbage,
+cauliflower, turnip, mignonette, and some other plants.
+
+The female lays her eggs on the under side of the leaves of the food
+plants, generally, but sometimes on the upper sides or even on the
+leaf stalks. They are sugar loaf shaped, flattened at the base, and
+with the apex cut off square at the top, pale lemon yellow in color,
+about one twenty-fifth of an inch long and one fourth as wide, and
+have twelve longitudinal ribs with fine cross lines between them.
+
+The eggs hatch in about a week, and the young caterpillars, which are
+very pale yellow, first eat the shells from which they have escaped,
+and then spin a carpet of silk, upon which they remain except when
+feeding. They now eat small round holes through the leaves, but as
+they grow older change to a greenish color, with a pale yellow line
+along the back, and a row of small yellow spots along the sides, and
+eat their way down into the head of the cabbage.
+
+[Illustration: FIG. 14.]
+
+Having reached its full growth, the caterpillar, Fig. 14, a, which is
+about an inch in length, wanders off to some sheltered place, as under
+a board, fence rail, or even under the edge of clapboards on the side
+of a building, where it spins a button of silk, in which to secure its
+hind legs, then the loop of silk to support the forward part of the
+body.
+
+It now casts its skin, changing to a chrysalis, Fig. 14, b, about
+three-fourths of an inch in length, quite rough and uneven, with
+projecting ridges and angular points on the back, and the head is
+prolonged into a tapering horn. In color they are very variable, some
+are pale green, others are flesh colored or pale ashy gray, and
+sprinkled with numerous black dots. The winter is passed in the
+chrysalis stage.
+
+After the caterpillar changes to a chrysalis, their minute parasites
+frequently bore through the outside and deposit their eggs within.
+These hatch before the time for the butterflies to emerge, and feeding
+on the contents, destroy the life of the chrysalis.
+
+Birds and spiders are of great service in destroying these insects.
+
+The pupae should be collected and burned if the abdomen is flexible;
+but if the joints of the abdomen are stiff and cannot be easily moved,
+they should be left, as they contain parasites.
+
+Several applications of poisons have been used, the best results being
+obtained from the use of pyrethrum as a powder blown on to the plants
+by a hand bellows, during the hottest part of the day, in the
+proportion of one part to four or five of flour.
+
+As the eggs are laid at different times, any application, to be
+thoroughly tested, must be repeated several times.
+
+
+THE APPLE TREE TENT CATERPILLAR.
+
+_Clisiocampa Americana_ (Harr.)
+
+
+Large, white, silken web-like tents, Fig. 15, are noticed by the
+roadsides, in the early summer, on wild cherry trees, and also on
+fruit trees in orchards, containing numerous caterpillars of a
+blackish color, with fine gray hairs scattered over the body.
+
+This well known pest has been very abundant throughout the State for
+several years past, and the trees in many neglected orchards have been
+greatly injured by it, some being entirely stripped of their leaves.
+The trees in these orchards and the neglected ones by the roadsides
+form excellent breeding places for this insect, and such as are of
+little of no value should be destroyed. If this were well done, and
+all fruit growers in any given region were to destroy all the tents on
+their trees, even for a single season, the work of holding them in
+check or destroying them in the following year would be comparatively
+light.
+
+[Illustration: FIG. 15.]
+
+The moths, Fig. 16, appear in great numbers in July, their wings
+measuring, when expanded, from one and a quarter to one and a half
+inches or more. They are of a reddish brown color, the fore wings
+being tinged with gray on the base and middle, and crossed by two
+oblique whitish stripes.
+
+[Illustration: FIG. 16.]
+
+The females lay their eggs, about three hundred in number, in a belt,
+Fig. 15, c, around the twigs of apple, cherry, and a few other trees,
+the belt being covered by a thick coating of glutinous matter, which
+probably serves as a protection against the cold weather during
+winter.
+
+The following spring, when the buds begin to swell, the egg hatch and
+the young caterpillar seek some fork of a branch, where they rest side
+by side. They are about one-tenth of an inch long, of a blackish
+color, with numerous fine gray hairs on the body. They feed on the
+young and tender leaves, eating on an average two apiece each day.
+Therefore the young of one pair of moths would consume from ten to
+twelve thousand leaves; and it is not uncommon to see from six to
+eight nests or tents on a single tree, from which no less than
+seventy-five thousand leaves would be destroyed--a drain no tree can
+long endure.
+
+As the caterpillars grow, a new and much larger skin is formed
+underneath the old one, which splits along the back and is cast off.
+When fully grown, Fig. 15, a and b, which is in about thirty-five to
+forty days after emerging from the eggs, they are about two inches
+long, with a black head and body, with numerous yellowish hairs on the
+surface, with a white stripe along the middle of the back, and minute
+whitish or yellowish streaks, which are broken and irregular along the
+sides; and there is also a row of transverse, small, pale blue spots
+along each side of the back.
+
+As they move about they form a continuous thread of silk from a fleshy
+tube on the lower side of the mouth, which is connected with the
+silk-producing glands in the interior of the body, and by means of
+this thread they appear to find their way back from the feeding
+grounds. It is also by the combined efforts of all the young from one
+belt of eggs that the tents are formed.
+
+These caterpillars do not feed during damp, cold weather, but take two
+meals a day when it is pleasant.
+
+After reaching their full growth, they leave their tents and scatter
+in all directions, seeking for some protected place where each one
+spins its spindle-shaped cocoon of whitish silk intermingled with
+sulphur colored powder, Fig. 15, d. They remain in these cocoons,
+where they have changed to pupae, from twenty to twenty-five days,
+after which the moths emerge, pair, and the females lay their eggs for
+another brood.
+
+Several remedies have been suggested, a few of which are given below.
+Search the trees carefully, when they are bare, for clusters of eggs;
+and, when found, cut off the twigs to which they are attached, and
+burn them.
+
+As soon as any tents are observed in the orchard they should be
+destroyed, which may be readily and effectually done by climbing the
+trees, and with the hand protected by a mitten or glove, seize the
+tent and crush it with its entire contents; also swab them down with
+strong soapsuds or other substances; or tear them down with a rounded
+bottle brush.
+
+Burning with a torch not only destroys the caterpillars but injures
+the trees.
+
+It should be observed, however, since the caterpillars, are quite
+regular in taking their meals, in the middle of the forenoon and
+afternoon, that they should be destroyed only in the morning or
+evening, when all are in the tent.
+
+Another remedy is to shower the trees with Paris green in water, in
+the proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE FOREST TENT CATERPILLAR.
+
+_Clisiocampa disstria_ (Huebner.)
+
+
+This species, commonly known as the forest tent caterpillar, closely
+resembles the apple tree tent caterpillar, but does not construct a
+visible tent. It feeds on various species of forest trees, such as
+oak, ash, walnut, hickory, etc., besides being very injurious to apple
+and other fruit trees. The moth, Fig. 17, b, expands an inch and a
+half or more. The general color is brownish yellow, and on the fore
+wings are two oblique brown lines, the space between them being darker
+than the rest of the wing. The eggs, Fig. 17, c and d, which are about
+one twenty fifth of an inch long and one fortieth wide, are arranged,
+three or four hundred in a cluster, around the twigs of the trees,
+Fig. 17, a. These clusters are uniform in diameter and cut off
+squarely at the ends. The eggs are white, and are firmly fastened to
+the twigs and to each other, by a brown substance, like varnish, which
+dries, leaving the eggs with a brownish covering.
+
+[Illustration: FIG. 17.]
+
+The eggs hatch about the time the buds burst, or before, and the young
+caterpillars go for some time without food, but they are hardy and
+have been known to live three weeks with nothing to eat, although the
+weather was very cold.
+
+[Illustration: FIG. 18.]
+
+As soon as hatched they spin a silken thread wherever they go, and
+when older wander about in search for food. The caterpillars are about
+one and a half inches long when fully grown, Fig. 18. The general
+color is pale blue, tinged with greenish low down on the sides, and
+everywhere sprinkled with black dots or points, while along the middle
+of the back is a row of white spots each side of which is an orange
+yellow stripe, and a pale, cream yellow stripe below that. These
+stripes and spots are margined with black. Each segment has two
+elevated black points on the back, from each of which arise four or
+more coarse black hairs. The back is clothed with whitish hairs, the
+head is dark bluish freckled with black dots, and clothed with black
+and fox-colored hairs, and the legs are black, clothed with whitish
+hairs.
+
+At this stage the caterpillars may be seen wandering about on fences,
+trees, and along the roads in search of a suitable place to spin their
+cocoons, which are creamy white, and look very much like those of the
+common tent caterpillar, except that they are more loosely
+constructed.
+
+Within the cocoons, in two or three days they transform to pupae of a
+reddish brown color, densely clothed with short pale yellowish hairs.
+The moths appear in two or three weeks, soon lay their eggs and then
+die. The insects are not abundant many years in succession, as their
+enemies, the parasites, increase and check them.
+
+Many methods have been suggested for their destruction, but the most
+available and economical are to remove the clusters of eggs whenever
+found, and burn them, and to shower the trees with Paris green in the
+proportion of one pound to one hundred and fifty gallons of water.
+
+
+THE STALK BORER.
+
+_Gortyna nitela_ (Gruen.)
+
+
+The perfect moth, Fig. 19, 1, expands from one to one and a half
+inches. The fore wings are a mouse gray color, tinged with lilac and
+sprinkled with fine yellow dots, and distinguished mainly by a white
+band extending across the outer part. The moths hibernate in the
+perfect state, and in April or May deposit their eggs singly on the
+outside of the plant upon which the young are to feed. As soon as the
+eggs hatch, which is in about a month, the young larvae, or
+caterpillars, gnaw their way from the outside into the pith.
+
+[Illustration: FIG. 19.]
+
+The plant does not show any sign of decay until the caterpillar is
+fully grown, when it dies. The caterpillar, Fig. 19, 2, is about one
+and one-fourth inches long, of a reddish brown color, with whitish
+stripes along the body. The stripes on the sides are not continuous,
+and the shading of the body varies, being darker on the anterior than
+on the posterior portion. When fully grown, Fig. 20, the color is
+lighter and the stripes are broader. At this stage of life it burrows
+into the ground just beneath the surface, and changes into the pupa
+state. The pupa is three-fourths of an inch long, and of a mahogany
+brown color. The perfect moth appears about the first of September,
+and there is only one brood in a season.
+
+[Illustration: FIG. 20.]
+
+The caterpillars feed in the stalks of corn, tomatoes, potatoes,
+dahlias, asters, and also in young currant bushes, besides feeding on
+many species of weeds. By a close inspection of the plants about the
+beginning of July, the spot where the borer entered, which is
+generally quite a distance from the ground, may be detected, and the
+caterpillar cut out without injury to the plant. This plan is
+impracticable for an extensive crop, but by destroying the borers
+found in the vines that wilt suddenly, one can lessen the number
+another year.
+
+
+THE PYRAMIDAL GRAPEVINE CATERPILLAR.
+
+_Pyrophila pyramidoides_ (Guen.)
+
+
+This caterpillar, Fig. 21, is generally found on grapevines early in
+June, but also feeds on apple, plum, raspberry, maple, poplar, etc. It
+is about an inch and a half in length, with the body tapering toward
+the head; of a whitish green color, darker on the sides; with a
+longitudinal white stripe on the back, broader on the last segments.
+Low down on each side is a bright yellow stripe, between this and the
+one on the back is another less distinct, and the under surface of the
+body is pale green.
+
+[Illustration: FIG. 21.]
+
+The caterpillar is fully grown about the middle or last of June, when
+it descends to the ground, draws together some of the fallen leaves,
+and makes a cocoon, in which it soon changes to a mahogany brown pupa.
+
+[Illustration: FIG. 22.]
+
+In the latter part of July the perfect moth, Fig. 22, emerges,
+measuring, when its wings are expanded, about one and three-fourths
+inches; the fore wings are dark brown shaded with lighter, with dots
+and wavy lines of dull white. The hind wings are reddish, or of a
+bright copper color, shading to brown on the outer angle of the front
+edge of the wing, and paler toward the hinder and inner angle.
+
+The under surface of the wings is lighter than the upper, and the body
+is dark brown, with its posterior portion banded with lines of a paler
+hue.
+
+This pest may be destroyed by hand picking, or by jarring the trees or
+vines on which they are feeding, when they will fall to the ground and
+may be crushed or burned.
+
+
+THE GRAPE BERRY MOTH.
+
+_Eudemis botrana_ (S.V.)
+
+
+The moths emerge and fly early in June, and are quite small,
+measuring, when the wings are expanded, only two-fifths of an inch,
+Fig. 23, a, enlarged. The fore wings are purplish or slate brown from
+the base to the middle, the outer half being irregularly marked with
+dark and light brown.
+
+[Illustration: FIG. 23.]
+
+These insects are two-brooded and the first brood feeds not only on
+the leaves of the grape, but on tulip, sassafras, vernonia and
+raspberry. The caterpillars of the second brood emerge when the grapes
+are nearly grown, and bore in them a winding channel to the pulp,
+continuing to eat the interior of the berry till the pulp is all
+consumed, Fig. 23, d, when, if not full grown, they draw one or two
+other berries close to the first and eat the inside of those.
+
+The mature caterpillar, Fig. 23, b, measures about half an inch in
+length, is dull greenish, with head and thoracic shield somewhat
+darker; the internal organs give the body a reddish tinge. It then
+leaves the grape and forms its cocoon by cutting out a piece of a
+leaf, leaving it hinged on one side; then rolling the cut end over,
+fastens it to the leaf, thus making for itself a cocoon in which to
+pupate. The pupa is dark reddish brown.
+
+The second generation passes the winter in the pupa state, attached to
+leaves which fall to the ground; therefore, if all the dead and dried
+leaves be gathered in the fall and burned, also all the decayed fruit,
+a great many of these insects would be destroyed. As the caterpillars
+feed inside of the berry, no spraying of the vines with poisons would
+reach them. The caterpillar makes a discolored spot where it enters
+the berry, Fig. 23, c. Therefore the infested fruit may be easily
+detected and destroyed.
+
+There is a small parasite that attacks this insect and helps to keep
+it in check. The insect has been known in Europe over a hundred years.
+It is not certain when it was introduced into America, but it is now
+found from Canada to the Gulf of Mexico, and from the Atlantic to the
+Pacific Ocean.
+
+
+THE CODLING MOTH.
+
+_Carpocapsa pomonella_ (Linn.)
+
+
+This well known insect has a world-wide reputation, and is now found
+wherever apples are raised.
+
+[Illustration: FIG. 24.]
+
+The moths are on the wing about the time the young apples are
+beginning to set, and the female lays a single egg in the blossom end
+of each apple. The fore wings of the moths when expanded, Fig. 24, g
+(f, with the wings closed), measure about half an inch across, and are
+marked with alternate wavy, transverse streaks of ashy gray and brown,
+and have on the inner hind angle a large tawny brown, horseshoe shaped
+spot, streaked with light bronze or copper color. The hind wings and
+abdomen are light brown with a luster of satin.
+
+Each female lays about fifty eggs, which are minute, flattened,
+scale-like bodies of a yellowish color. In about a week the eggs hatch
+and the tiny caterpillar begins to eat through the apple to the core,
+Fig. 24, a, pushing its castings out through the hole where it
+entered, Fig. 24, b. Oftentimes these are in sight on the outside in a
+dark colored mass, thus making wormy apples plainly seen at quite a
+distance.
+
+The caterpillar is about two-fifths of an inch in length, of a glossy,
+pale yellowish white color, with a light brown head. The skin is
+transparent and the internal organs give to it a reddish tinge.
+
+When mature the caterpillars, Fig. 24, e, top of head and second
+segment, h, emerge from the apples and seek some sheltered place, such
+as crevices of bark, or corners of the boxes or barrels in which the
+fruit is stored, where they spin a tough whitish cocoon, Fig. 24, i,
+in which they remain unchanged all winter, and transform to pupae, Fig.
+24, d, the next spring, the perfect moths emerging in time to lay
+their eggs in the new crop of apples.
+
+One good remedy is to gather all the fallen apples, and feed them to
+hogs; another is to let swine and sheep run in the orchard, and eat
+the infested fruit.
+
+It has been recommended to place bands of cloth or hay around the
+trunks of the trees for the caterpillars to spin their cocoons
+beneath, and to remove them at the proper time, and put them in
+scalding water to destroy the worms.
+
+By far the most successful method as yet adopted is to shower the
+apple trees with Paris green in water, one pound to one hundred and
+fifty gallons of water, when the apples are about the size of peas,
+and again in about a week.
+
+
+THE CABBAGE LEAF MINER.
+
+_Plutella cruciferarum_ (Zell.)
+
+
+The cabbage leaf miner is not a native of this country, but was
+imported from Europe.
+
+[Illustration: FIG. 25.]
+
+The perfect moth, Fig. 25, f, with the wings expanded (h, with the
+wings closed, g, a dark variety), measures three-quarters of an inch.
+The fore wings are ashy gray, and on the hinder margin is a white or
+yellowish white stripe having three points extending into the gray,
+thus forming, when the wings are closed, three diamond-shaped white
+spots. Generally there is a dark brown stripe between the white and
+the gray. There are also black dots scattered about on the anterior
+part of these wings.
+
+The hind wings are leaden brown, and the under side of all the wings
+is leaden brown, glossy, and without any dots.
+
+The antennae are whitish with dark rings, and the abdomen white. There
+are two broods of this insect in this region, the moths of the first
+appearing in May, and those of the second in August. They hibernate in
+the pupa stage.
+
+The caterpillars, Fig. 25, a (b, the top and c, the side of a
+segment), appear in June or July and September; they are small and
+cylindrical, tapering at both ends, pale green, and about one-fourth
+of an inch long. The head has a yellowish tinge, and there are several
+dark stiff hairs scattered over the body.
+
+When ready to transform, this caterpillar spins a delicate gauze-like
+cocoon, Fig. 25, e, made of white, silken threads, on the under side
+of a cabbage leaf. The pupa, Fig. 25, d, and i, the end of a pupa, is
+commonly white, sometimes shaded with reddish brown, and can be
+distinctly seen through the silken case.
+
+The first brood is more injurious than the second, as it feeds on the
+young cabbage leaves before the head is formed, and this must surely
+stunt the growth and make weak, sickly plants; while the second brood
+feeds only on the outside leaves. The caterpillars are very active,
+wriggling violently when disturbed, and falling by a white silken
+thread.
+
+Hot dry weather is favorable to them and enables them to multiply
+rapidly. Advantage has been taken of this fact, and spraying the
+plants thoroughly with water is strongly recommended. Prof. Riley
+states that the insects are very readily destroyed by pyrethrum. There
+are two species of spiders and a species of ichneumon fly that destroy
+them.
+
+
+THE GARTERED PLUME MOTH.
+
+_Oxyptilus periscelidactylus_ (Fitch.)
+
+
+The caterpillars of this species draw together the young grape leaves,
+Fig. 26, a, in the spring, with fine silken threads, and feed on the
+inside, thus doing much damage in proportion to their size. These
+caterpillars, Fig. 26, a, and e, a segment greatly enlarged, are full
+grown in about two weeks, when they are about one-fourth of an inch
+long, pale green with whitish hairs arising from a transverse row of
+warts on each segment.
+
+Early in June they transform to pupae, Fig. 26, b, which are pale green
+at first and change to dark brown. The surface is rough and the head
+is cut off obliquely, while on the upper side near the middle are two
+sharp pointed horns, Fig. 26, c. They remain in this stage from a week
+to ten days, when the moths emerge.
+
+[Illustration: FIG. 26.]
+
+The moths, Fig. 26, d, belong to the family commonly known as plume
+moths or feather wings (Pterophoridae), from having their wings divided
+into feather-like lobes. When the wings are expanded they measure
+about seven-tenths of an inch across. They are yellowish brown with a
+metallic luster, and have several dull whitish streaks and spots. The
+fore wings are split down the middle about half way to their base, the
+posterior half having a notch in the outer margin. The body is
+somewhat darker than the wings.
+
+It is not known positively in what stage the winter is passed, but it
+is supposed to be the perfect, or imago stage. The unnatural grouping
+and spinning of the leaves together leads to their detection, and they
+can be easily destroyed by hand picking and then crushing or burning
+them.
+
+       *       *       *       *       *
+
+
+
+
+THE BREEDS OF DOGS.
+
+
+The dog exhibitions that have annually taken place for the last eight
+years at Paris and in the principal cities of France have shown how
+numerous and varied the breeds of dogs now are. It is estimated that
+there are at present, in Europe, about a hundred very distinct and
+very fine breeds (that is to say, such as reproduce their kind with
+constant characters), without counting a host of sub-breeds or
+varieties that a number of breeders are trying to fix.
+
+Most of the breeds of dogs, especially those of modern creation, are
+the work of man, and have been obtained by intercrossing older breeds
+and discarding all the animals that departed from the type sought. But
+many of these breeds are also the result of accident, or rather of
+modifications of certain parts of the organism--of a sort of rachitic
+or teratological degeneration which has become hereditary and has been
+due to domestication; for it is proved that the dog is the most
+anciently domesticated animal, and that its submission to man dates
+back to more than five thousand years. Such is the origin of the
+breeds of terriers, bulldogs, and all of the small house dogs.
+
+Man has often, designedly or undesignedly, aided in the production of
+breeds of this last category by submitting the dog to a regimen
+contrary to nature, or setting to work to reproduce an animal born
+monstrous, either for curiosity or for interest. As well known, the
+accidental characters and the spontaneous modifications which work no
+injury to the essential functions of life became easily hereditary,
+and the same is the case with certain artificial modifications pursued
+for a long series of generations.
+
+It was the opinion of Buffon that the breeds of dogs, which were
+already numerous in his time, were all derived from a single type,
+which, according to him, was the shepherd's dog. Other scientists have
+insisted that the dog descended from the wolf, and others from the
+jackal. At the present time, it is rightly admitted that several
+species of wild dogs have concurred in the formation of the different
+breeds of dogs as we now have them.
+
+In the lacustrine habitations of the stone age in Sweden, and in the
+_kjoekkenmoedding_ (kitchen remains) of Denmark, of the same epoch, we
+find the remains of a dog, which, according to Rutymeyer, belongs to a
+breed which is constant up to its least details, and which is of a
+light and elegant conformation, of medium size, with a spacious and
+rounded cranium and a short, blunt muzzle, and a medium sized jaw, the
+teeth of which form a regular series.
+
+This dog, which has been named by geologists _Canis palustris_, fully
+resembles in size, slenderness of the limbs, and weakness of the
+muscular insertions, the spaniel, the brach hound, or the griffon.
+
+This dog of the stone age is entirely distinct from the wolf and
+jackal, of which some regard the domestic dog as a descendant, and as
+it has appeared in Denmark as well as in Sweden, there is no doubt
+that this species, peculiar to Europe, was subjugated by man and used
+by him, in the first place, for hunting, and later on for guarding
+houses and cattle. Later still, in the age of metals, we observe the
+appearance, both in Denmark and Sweden, of larger and stronger breeds
+of dogs, having in their jaws the character of mastiffs, and probably
+introduced by the first emigrants from Asia.
+
+There are, moreover, historic proofs that the dogs of the strongest
+breeds are indigenous to Asia, where we still find the dog of Thibet,
+the most colossal of all; in fact, in Pliny we read the following
+narrative: Alexander the Great received from a king of Asia a dog of
+huge size. He wished to pit it against bears and wild boars, but the
+dog remained undisturbed and did not even rise, and Alexander had it
+killed. On hearing of this, the royal donor sent a second dog like
+the first, along with word that these dogs did not fight so weak
+animals, but rather the lion and the elephant, and that he had only
+two of such individuals, and in case that Alexander had this one
+killed, too, he would no longer find his equal. Alexander matched this
+dog with a lion and then with an elephant, and he killed them both.
+Alexander was so afflicted at the premature death of the first dog,
+that he built a city and temples in honor of the animal.
+
+Did the mountainous province of Epirus called Molossia, in ancient
+Greece, give its name to the _molossi_ that it produced, or did these
+large dogs give their name to the country? At all events, we know that
+it was from Epirus that the Romans obtained the molossi which fought
+wild animals in the circuses, and that from Rome they were introduced
+into the British islands and have became the present mastiffs.
+
+Although our hunting and shepherd's dogs have a European and the
+mastiffs an Asiatic ancestry, the ancestry of the harriers is African,
+and especially Egyptian; in fact, in Upper Egypt we find a sort of
+large white jackal (_Simenia simensis_) with the form of a harrier,
+and which Paul Gervais regarded with some reason as the progenitor of
+the domestic harrier, and a comparison of their skulls lends support
+to this opinion.
+
+A study of the most ancient monuments of the Pharaohs shows that the
+ancient Egyptians already had at least five breeds of dogs: two very
+slim watch dogs, much resembling the harrier, a genuine harrier, a
+species of brach hound and a sort of terrier with short and straight
+legs. All these dogs had erect ears, except the brach, in which these
+organs were pendent, and this proves that the animal had already
+undergone the effects of domestication to a greater degree than the
+others. The harrier of the time of the Pharaohs still exists in great
+numbers in Kordofan, according to Brehm.
+
+Upon the whole, we here have, then, at least three stocks of very
+distinct dogs: 1, a hunting or shepherd's dog, of European origin; 2,
+a mastiff, typical of the large breed of dogs indigenous to Asia; and
+3, a harrier, indigenous to Africa.
+
+We shall not follow the effects of the combination of these three
+types through the ages, and the formation of the different breeds; for
+that we shall refer our readers to a complete work upon which we have
+been laboring for some years, and two parts of which have already
+appeared.[1]
+
+[Footnote 1: Les Races des Chiens, in La Bibliotheque de l'Eleveur.]
+
+We shall rapidly pass in review the different breeds of dogs that one
+may chance to meet with in our dog shows, beginning with the largest.
+It is again in mountainous countries that the largest dogs are raised,
+and the character common to all of these is a very thick coat. The
+largest of all, according to travelers, is the Thibetan dog. Buffon
+tells of having seen one which, when seated, was five feet in height.
+One brought back by the Prince of Wales from his voyage to the Indies
+was taller in stature, stronger and more stocky than a large mastiff,
+from which it differed, moreover, in its long and somewhat coarse
+hair, which was black on the back and russet beneath, the thighs and
+the tail being clothed with very long and silky hair.
+
+In France, we have a beautiful mountain dog--the dog of the
+Pyrenees--which is from 32 to 34 inches in height at the shoulders,
+and has a very thick white coat, spotted above with pale yellow or
+grayish fox color. It is very powerful, and is capable of
+successfully defending property or flocks against bears and wolves.
+
+The Alpine dog is the type of the mountain dog. It is of the same size
+as the dog of the Pyrenees, and differs therefrom especially in its
+coloring. It is white beneath, with a wide patch of orange red
+covering the back and rump. The head and ears are of the same color,
+with the addition of black on the edges; but the muzzle is white, and
+a stripe of the same color advances upon the forehead nearly up to the
+nape of the neck. The neck also is entirely white. There are two
+varieties of the Alpine or St. Bernard dog, one having long hair and
+the other shorter and very thick hair. We give in Fig. 1 a portrait of
+Cano, a large St. Bernard belonging to Mr. Gaston Leonnard.
+
+[Illustration: FIG. 1--LARGE ST. BERNARD DOG BELONGING TO MR. LEONARD.]
+
+Although this breed originated at the celebrated convent of St.
+Bernard, it no longer exists there in a state of purity, and in order
+to find fine types of it we have to go to special breeders of
+Switzerland and England. The famous Plinnlimon, which was bought for
+$5,000 by an American two or three years ago, and about which there
+was much talk in the papers, even the political ones, was born and
+reared in England. It appears that it is necessary, too, to reduce the
+number of life-saving acts that it is said are daily performed by the
+St. Bernard dogs. This is no longer but a legend. There was, it is
+true, a St. Bernard named Barry, now exhibited in a stuffed state in
+the Berne Museum, which accomplished wonders in the way of saving
+life, but this was an exception, and the reputation of this animal has
+extended to all others of its kind. These latter are simply watch dogs
+kept by the monks for their own safety, and which do not go at all by
+themselves alone to search for travelers that have lost their way in
+the snow.
+
+The Newfoundland dog, which differs from the preceding in its wholly
+black or black and white coat, was, it appears, also of mountain
+origin. According to certain authors, it is indigenous to Norway, and
+was carried to Newfoundland by the Norwegian explorers who discovered
+the island. Adapted to their new existence, they have become excellent
+water dogs, good swimmers, and better life savers by far than the
+majority of their congeners.
+
+Is it from descending to the plain that the mountain dogs have lost
+their long hair and have become short haired dogs like the English dog
+or mastiff and the German or large Danish dogs? It is very probable.
+At all events, it is by this character of having short hair that
+mastiffs are distinguished from the mountain dogs. Again, the large
+breed of dogs are distinguished from each other by the following
+characters: The mastiff is not very high at the shoulders (30 inches),
+but he is very heavy and thick set, with powerful limbs, large head,
+short and wide muzzle and of a yellowish or cafe-au-lait color
+accompanying a black face; that is to say, the ears, the circumference
+of the eyes and the muzzle are of a very dark color. The German or
+large Danish dogs constitute but one breed, but of three varieties,
+according to the coat: (1) those whose coat is of a uniform color, say
+a slaty gray or isobelline of varying depth, without any white spots;
+(2) those having a fawn colored coat striped transversely with black
+like the zebra, but much less distinctly; (3) those having a spotted
+coat, that is to say, a coat with a white ground strewed with
+irregular black spots of varying size. These, like those of the first
+variety are generally small-eyed. Whatever be the variety to which
+they belong, the German or large Danish dogs are slimmer than, and not
+so heavy as, the mastiffs. Some, even, are so light that it might be
+supposed that they had some heavier blood in their veins. They have
+also a longer muzzle, although square, and are quicker in gait and
+motions.
+
+The largest dogs are to be met with in this breed, and the beautiful
+Danish dog belonging to Prof. Charcot (Fig. 2) is certainly the
+largest dog in France and perhaps in Europe. It measures 36 inches at
+the shoulders and has an osseous and muscular development perfectly in
+keeping with its large stature, and at the same time has admirable
+proportions and lightness, and its motions are comparable to those of
+the finest horse.
+
+[Illustration: FIG. 2--DR. CHARCOT'S LARGE DANISH DOG.]
+
+Among the English dogs or mastiffs, we very frequently meet with
+individuals in which the upper incisors and canines are placed back of
+the corresponding ones in the lower jaw, this being due to a slight
+shortening of the bones of the upper jaw, not visible externally. This
+is the first degree of an artist of teratological development, which,
+since the middle ages, has become very marked in certain subjects, and
+has given rise to a variety in which this defect has become
+hereditary. Such is the origin of the breed of bulldogs. The latter
+were originally as large as the mastiffs. Carried to Spain under
+Philip II., they have there preserved their primitive characters, but
+the bulldogs remaining in England have continued to degenerate, so
+that now the largest are scarcely half the size of the Spanish
+bulldog, and the small ones attain hardly the size of the pug,
+although they preserve considerable width of chest and muscular
+strength.
+
+
+POINTERS.
+
+Man hunted for ages with dogs that he united in a pack; but these
+packs were of a very heterogeneous composition, since they included
+strong dogs, light dogs very swift of foot, shepherds' dogs, and
+others noted for acuteness of scent, and even mongrels due to a
+crossing with the wolf. It is from the promiscuousness of all these
+breeds that has arisen our ordinary modern dog.
+
+The pointer is of relatively recent creation, and is due to the
+falconers. In our western countries, falconry dates from the fourth
+and fifth centuries, as is proved by the capitularies of Dagobert.
+This art, therefore, was not brought to us from the East by the
+crusaders in the twelfth and thirteenth centuries, as stated by Le
+Maout in his Natural History of Birds.
+
+The falconer soon saw the necessity of having a dog of nice scent
+having for its role the finding or hunting up of game without pursuing
+it, in order to permit the falcons themselves to enter into the sport.
+This animal was called the bird dog, and was regarded as coming from
+various countries, especially from Spain, whence the name of spaniel
+that a breed of pointers has preserved. It is quite curious to find
+that for three or four centuries back there have been no spaniels in
+Spain. From Italy also and from southern climes comes what is called
+the _bracco_, whence doubtless is derived the French name _braque_ and
+English brach. Finally the _agasse_ of the Bretons was certainly also
+one of the progenitors of our present pointers. It was, says Oppian, a
+breed of small and very courageous dogs, with long hair, provided with
+strong claws and jaws, that followed hares on the sly under shelter of
+vine-stocks and reeds and sportively brought them back to their
+masters after they had captured them. We have certainly here the
+source of our barbets and griffons.
+
+Finally the net hunters of the middle ages also contributed much to
+the creation of the pointer, for it is to them that we owe the setter.
+It is erroneously, in fact, that certain authors have attributed the
+creation of this dog to hunters with the arquebuse, since this weapon
+did not begin to be utilized in hunting until the sixteenth century.
+Gaston Phoebus, who died in 1391, shows, in his remarkable work, that
+the net hunters made use of Spanish setters and that it was they who
+created the true pointer--the animal that fascinates game by its gaze.
+By the same pull of their draw net they enveloped in its meshes both
+the setter and the prey that it held spellbound.
+
+Upon the whole, we see that at the end of the middle ages there
+existed three types of pointers: spaniels, brachs and very hairy dogs,
+that Charles Estienne, in his Maison Rustique, of the sixteenth
+century, calls barbets. It is again with these three types that are
+connected all the present pointers, which we are going to pass rapidly
+in review.
+
+_The Brach hounds_.--To-day we reserve the name of brachs for all
+pointers with short hair. The type of the old brach still exists in
+Italy, Spain, the south of France and in Germany. It is characterized
+by its large size, its robust form, its large head, its long, flat
+ears, its square muzzle separated from the forehead by a deep
+depression, its large nose, often double (that is to say, with
+nostrils separated by a deep vertical groove), its pendent lips, its
+thick neck, its long and strong paws provided with dew claws, both on
+the fore and the hind feet, and its short hair, which is usually white
+and marked with brown or orange-yellow spots. The old brach breed has
+been modified by the breeders of different countries, either by
+hygiene or by crossing with ordinary dogs, according to the manner of
+hunting, according to taste, and even according to fashion. Thus in
+England, where "time is money" reigns in every thing and where they
+like to hunt quickly and not leisurely, the brach has been rendered
+lighter and swifter of foot and has become the pointer. In France,
+while it has lost a little in size and weight, it has preserved its
+moderate gait and has continued to hunt near its master, "under the
+gun," as they say. The same is the case in Spain, Italy and Germany
+even. In France there are several varieties or sub-breeds of brach
+hounds. The old French brach, which is nothing more than the old type,
+preserved especially in the south, where it is called the Charles the
+Tenth brach, is about twenty-four inches in height, and has a white
+and a maroon coat, which is somewhat coarse. It often has a cleft nose
+and dew-claws on all the feet. The brach of the south scarcely differs
+from the preceding except in color. Its coat has a white ground
+covered with pale orange blotches and spots of the same color. The St.
+Germain brach is finer bred, and appears to be a pointer introduced
+into France in the time of Charles X. It has a very fine skin, very
+fine hair of a white and orange color. The Bourbon brach has the
+characters of the old French brach, with a white coat marked here and
+there with large brown blotches, and the white ground spotted with the
+same color; but what particularly characterizes this dog is that it is
+born with a stumpy tail, as if three-quarters of it had been chopped
+off. The Dupuy brach is slender and has a narrow muzzle, as if it had
+some harrier blood in its veins. It is white, with large dark maroon
+blotches. The Auvergne brach resembles the southern brach, but has a
+white and black coat spotted with black upon white. The pointer, or
+English brach (Fig. 3), descends from the old Spanish brach, but has
+been improved and rendered lighter and much swifter of foot by the
+introduction of the blood of the foxhound into its veins, according to
+the English cynegetic authors themselves. The old pointer was of a
+white and orange color, and was indistinguishable from our St.
+Germain. The pointer now fancied is white and maroon and has a
+stronger frame than the pointer of twenty years ago. The Italian
+brachs are heavy, with lighter varieties, usually white and orange
+color, more rarely _roan_, and provided with dew-claws, this being a
+sign of purity of breed according to Italian fanciers. The German
+brachs are of the type of the old brach, with a stiff white and
+maroon coat, the latter color being so extensively distributed in
+spots on the white as to make the coat very dark.
+
+[Illustration: FIG 3.--POINTER.]
+
+_Spaniels_.--The old type of spaniel has nearly disappeared, yet we
+still find a few families of it in France, especially in Picardy and
+perhaps in a few remote parts of Germany. The old spaniel was of the
+same build as the brach, and differed from it in that the head, while
+being short-haired, was provided with ears clothed with long, wavy
+hair. The same kind of hair also clothed the whole body up to the
+tail, where it constituted a beautiful tuft. The Picard spaniel is a
+little lighter than the old spaniel. It has large maroon blotches upon
+a white ground thickly spotted with maroon, with a touch of flame
+color on the cheeks, over the eyes, and on the legs. The Pont-Andemer
+spaniel is a Norman variety, with very curly hair, almost entirely
+maroon colored, the white parts thickly spotted with a little color as
+in the Picard variety, and a characteristic forelock on the top of the
+head.
+
+[Illustration: FIG 4.--ENGLISH SETTERS.]
+
+In England, the spaniel has given rise to several varieties. In the
+first place there are several sub-breeds of setters, viz.: The English
+setter, still called laverack, which has large black or orange-colored
+blotches on the head, the rest of the body being entirely white, with
+numerous spots of the same color as the markings on the head (Fig. 4);
+the Irish setter, which is entirely of a bright yellowish mahogany
+color; and the Gordon setter, which is entirely black, with orange
+color on the cheeks, under the throat, within and at the extremity of
+the limbs (Fig. 5). Next come the field spaniels, a group of terrier
+spaniels, which includes the Clumber spaniel, which is white and
+orange color; the Sussex spaniel, which is white and maroon; the black
+spaniel, which is wholly black; and the cocker, which is the smallest
+of all, and is entirely black, and white and maroon, or white and
+orange-colored, or tricolored.
+
+[Illustration: FIG 5.--GORDON SETTER.]
+
+_Barbets and Griffons_.--To this latter category belong the dogs, _par
+excellence_, for hunting in swamps. The barbets are entirely covered
+with long curly hair, like the poodles, which are directly derived
+from them. They are white or gray, with large black or brown blotches.
+The griffons differ from the poodles in their coarse and stiff hair,
+which never curls. They have large brown blotches upon a white ground,
+which is much spotted or mixed, as in the color of the hair called
+roan. There is an excellent white and orange-colored variety. The
+griffons, neglected for a long time on account of the infatuation that
+was and is still had for English hunting dogs, are being received
+again with that favor which they have never ceased to be the object of
+in Germany and in Italy (where they bear the name of _spinone_).
+Breeders of merit, such as Mr. Korthals, in Germany, and Mr. E.
+Boulet, in France, are endeavoring to bring them into prominence (Fig.
+6). Finally, we reckon also among hunting dogs some very happy
+crosses between the spaniels and the barbets, which in England are
+called retrievers or water spaniels.--_P. Megnin, in La Nature_.
+
+[Illustration: FIG 6.--COARSE HAIRED GRIFFON.]
+
+       *       *       *       *       *
+
+
+
+
+RESTOCKING THE SEINE WITH FISH.
+
+
+A few days ago, at Bougival, a short distance below the dam of the
+Marly machine, there were put into water 40,000 fry of California
+trout and salmon, designed to restock the Seine, which, in this
+region, has been depopulated by the explosions of dynamite which last
+winter effected the breaking up of the ice jam that formed at this
+place.
+
+[Illustration: RESTOCKING THE SEINE WITH FISH.]
+
+The operation, which is quite simple in itself, attracted a large
+number of inquisitive people by reason of the exceptional publicity
+given to the conflict provoked by a government engineer, who, under
+the pretext that he had not been consulted, made objections to the
+submersion of the little fish. As well known, the affair was
+terminated by a sharp reprimand from Mr. Yves Guyot, addressed to his
+overzealous subordinate.
+
+It would have been a great pity, moreover, if this interesting
+experiment had not taken place, and had not come to corroborate the
+favorable results already obtained.
+
+In three years the California salmon reaches a weight of eleven
+pounds, and, from this time, is capable of reproduction. Its flesh is
+delicious, and comparable to that of the trout, the development of
+which is less rapid, but just as sure.
+
+The fry put into the water on Sunday were but two months old. The
+trout were, on an average, one and a half inches in length, and the
+salmon two and three-quarter inches. They were transported in three
+iron plate vessels, weighing altogether, inclusive of the water, 770
+lb., and provided with air tubes through which, during the voyage, the
+employes, by means of pumps, assured the respiration of the little
+fish.
+
+Our engraving represents the submersion at the moment at which
+the cylinders (of which the temperature has just been taken and
+compared with that of the Seine, in order to prevent too abrupt a
+transition for the fry) are being carefully let down into the
+river.--_L'Illustration_.
+
+       *       *       *       *       *
+
+
+
+
+Figures show that the consumption of iron in general
+construction--other than railroads--in this country has grown from a
+little more than a million and a half of tons in 1879 to more than six
+million tons in 1889. Much of this increase has gone into iron
+buildings. By using huge iron frames and thin curtain walls for each
+story supported thereon, as is done in a building going up on lower
+Broadway, New York city, a good deal of space can be saved.
+
+       *       *       *       *       *
+
+
+
+
+MODERN ARMOR.
+
+By F.R. BRAINARD, U.S.N.
+
+
+The building of a navy, which has been actively going on for the past
+few years, has drawn public attention to naval subjects, and recent
+important experiments with armor plates have attracted large
+attention, hence it may not be amiss to give a description of the
+manufacture and testing of armor. It would be interesting to wade
+through the history of armor, studying each little step in its
+development, but we shall simply take a hasty glance at the past, and
+then devote our attention to modern armor and its immediate future.
+
+Modern armor has arrived at its present state of development through a
+long series of experiments. These experiments have been conducted with
+great care and skill, and have been varied from time to time as the
+improvements in the manufacture of materials have developed, and as
+the physical laws connected with the subject have been better
+understood. There has been very little war experience to draw from,
+and hence about all that is now known has been acquired in peaceful
+experiments.
+
+The fundamental object to be obtained by the use of armor is to keep
+out the enemy's shot, and thus protect from destruction the vulnerable
+things that may be behind it. The first serious effort to do this
+dates with the introduction of iron armor. With this form of armor we
+have had a small amount of war experience. The combat of the Monitor
+and Merrimac, in Hampton Roads, in May, 1862, not only marked an epoch
+in the development of models of fighting ships, but also marked one in
+the use of armor. The Monitor's turret was composed of nine one-inch
+plates of wrought iron, bolted together. Plates built in this manner
+form what is known as laminated armor. (See Fig. 1.) The side armor of
+the hull was composed of four one-inch plates. The Merrimac's casemate
+was composed of four one-inch plates or two two-inch plates backed by
+oak. The later monitors had laminated armor composed of one-inch
+plates. The foregoing, with the Albemarle and Tennessee rams under the
+Confederate flag, are about the sum of our practical experience in the
+use of armor.
+
+[Illustration: Fig. 1.]
+
+European nations took up the subject of armor and energetically
+conducted experiments which have cost large sums of money, but have
+given much valuable data. For a long time wrought iron was the only
+material used for armor, and the resisting power depending on the
+thickness; and the caliber and penetration of guns rapidly increasing,
+it was not long before a point was reached where the requisite
+thickness made the load of armor so great that it was impracticable
+for a ship to carry it. The question then arose as to what were the
+most important parts of a ship to protect. The attempted solutions of
+this question brought out various systems of distributions.
+
+Armored ships were formerly of two classes; in one the guns were
+mounted in broadside, in the other in turrets. Every part of the ship
+was protected with iron to a greater or less thickness. In more modern
+ships the guns are mounted in an armored citadel, in armored barbettes
+or turrets, the engines, boilers and waterline being the only other
+parts protected. There may be said to be three systems of armor
+distribution. The belt system consists in protecting the whole
+waterline by an armored belt, the armor being thickest abreast of the
+engines and boilers. The guns are protected by breastworks, turrets or
+barbettes, the other parts of the ship being unprotected. The French
+use the belt system, and our own monitors may be classed under it. The
+central citadel system consists in armoring that part of the waterline
+which is abreast of the engines and boilers. Forward and aft the
+waterline is unprotected, but a protective deck extends from the
+citadel in each direction, preventing the projectiles from entering
+the compartments below. The hull is divided into numerous compartments
+by water-tight bulkheads, and, having a reserve of flotation, the
+stability of the ship is not lost, even though the parts above the
+protective deck, forward and aft, be destroyed or filled with water.
+The guns are protected by turrets or barbettes. The deflective system
+consists in inclining the armor, or in so placing it that it will be
+difficult or impossible to make a projectile strike normal to the face
+of the plate. A plate that is inclined to the path of a projectile
+will, of course, offer greater resistance to penetration than one
+which is perpendicular; hence, when there is no other condition to
+outweigh this one, the armor is placed in such a manner as to be at
+the smallest possible angle with the probable path of the projectile.
+This system is designed to cause the projectile to glance or deflect
+on impact. Deflective armor should be at such an angle that the
+projectiles fired at it cannot bite, and hence the angle will vary
+according to the projectile most likely to be used. In the usual form
+of deflective deck the armor is at such a small inclination with the
+horizon that it becomes very effective. Turret and barbette armor may
+be considered as deflective armor. The term inclined armor denotes
+deflective armor that is inclined to the vertical. The kinds of armor
+that are in use may be designated as rolled iron, chilled cast iron,
+compound, forged and tempered steel, and nickel steel. Iron armor
+consists of wrought iron plates, rolled or forged, and of cast iron or
+chilled cast iron, as in the Gruson armor. Compound armor consists of
+a forged combination of a steel plate and an iron plate. Steel armor
+consists of wrought steel plates. Nickel-steel armor consists of
+plates made from an alloy of nickel and steel.
+
+I have spoken above of laminated armor. To secure the full benefit of
+this kind, the plates must be neatly fitted to each other; the
+surfaces must make close contact. This requires accurate machining,
+and hence is expensive. To overcome this point sandwiched armor was
+suggested. This consists in placing a layer of wood between the
+laminations, as shown in Fig. 2. It was found that laminated and
+sandwiched armor gave very much less resisting power than solid rolled
+plates of the same thickness. Wrought iron armor is made under the
+hammer or under the rolls, in the ordinary manner of making plates,
+and has been exhaustively studied and experimented with--more so than
+any other form of armor.
+
+[Illustration: Fig. 2.]
+
+Chilled cast iron armor is manufactured by Gruson, in Germany, and is
+used in sea coast defense forts of Europe.
+
+In 1867 several compound plates were made by Chas. Cammell & Co., of
+Sheffield, England, and were tested at Shoeburyness, in England, and
+at Tegel, in Russia. These plates were made by welding slabs of steel
+to iron; but the difficulties were so great that the idea was
+abandoned for the time.
+
+[Illustration: Fig. 3.]
+
+[Illustration: FIG. 4.]
+
+Compound armor, as now manufactured, is of two types: Wilson's patent,
+a backing of rolled iron, faced with Bessemer steel; Ellis' patent, a
+backing of rolled iron, faced with a plate of hard rolled steel,
+cemented with a layer of Bessemer steel. Both these kinds are
+manufactured in England and France in sizes up to fifty tons weight.
+The Wilson process is used at the works of Messrs. Cammell & Co., of
+Sheffield, England, and the Ellis process at the Atlas Works of Sir
+John Brown & Co., of the same place. These are the two leading
+manufacturers of compound plate.
+
+[Illustration: Fig. 5.]
+
+The method employed by Wilson in making compound plate is to first
+make a good wrought iron plate. To the surface of this and along each
+side of the length of the plate are fixed two small channel irons, as
+shown in Fig. 5. The plate is then raised to a welding heat in a gas
+furnace, and transferred to an iron flask or mould. Wedges are driven
+in between the back of the plate and the side of the mould, thus
+forcing the channel irons up snug against the opposite side of the
+mould. Moulding sand is then packed around the back and sides of the
+plate (see Fig. 6). The mould is lowered in a vertical position into a
+pit. Molten steel, manufactured by either the Siemens-Martin or
+Bessemer process, is then poured in through a trough that forms
+several streams, and forms the hard face of the plate. The molten
+steel as it runs down cleans the face of the wrought iron plate,
+scoring it in places, and, being of much higher temperature, the
+excessive heat carbonates the iron to a depth of one-eighth to
+three-sixteenths of an inch, forming a zone of mild steel between the
+hard steel and soft iron. The mould is placed in a vertical position
+to insure closeness of structure and the forcing of gases out of the
+steel. After solidifying, the whole plate is pressed, and passed
+through the rolls to obtain thorough welding. It is then bent, planed,
+fitted, tempered, and annealed to remove internal strains.
+
+[Illustration: Fig. 6.]
+
+In 1887, Wilson took out a patent for improvements in his process of
+making compound plates. In this method of manufacture he takes a
+wrought iron, fibrous plate, fifteen inches thick, built up from a
+number of thin plates. While hot from the forging press, he places
+this plate in an iron mould (see Fig. 7) about 28 inches deep, and
+upon it runs "ingot iron" or very mild steel to a depth of thirteen
+inches. In this form of mould the plate rests on brickwork, and is
+held in place by two grooved side clamps or strips which are caused to
+grip the plate by means of screws which extend through the sides of
+the mould. After solidifying, the plate, which is twenty-eight inches
+thick, is reheated and rolled down to eighteen inches. This is the
+iron backing of the finished plate, and it is again put in the iron
+mould and heated, when a layer of hard steel is run on the exposed
+surface of the original wrought iron plate to a depth of eight inches.
+This makes a plate about twenty-eight inches thick. It is taken from
+the mould, reheated, rolled, hammered or pressed down to twenty
+inches. After cooling, it is bent, planed, and fitted as desired, then
+tempered and annealed to relieve internal strains.
+
+[Illustration: Fig. 7.]
+
+The method employed by Ellis in making compound plates is to take two
+separate plates, one of good wrought iron and one of hard forged
+steel, placing the forged steel plate on the wrought iron plate,
+keeping them separate by a wedge frame or berm of steel around three
+sides, and placing small blocks of steel at various points near the
+middle of the plates (see Fig. 8). These blocks are called distance
+blocks. After covering all the exposed steel surfaces with ganister,
+the plates are put in a gas furnace and heated to a welding heat. They
+are then lowered into a vertical iron pit with the open side
+uppermost. The plates are held in position by hydraulic rams, which
+also prevent bulging. Molten steel of medium softness is then poured
+into the space between the plates, by means of a distributing trough
+having holes in the bottom, and after this has solidified, the whole
+plate is placed under the hydraulic press and reduced about twenty per
+cent. in thickness. The plate is then passed through the rolls, bent,
+planed, fitted, tempered, and annealed to reduce internal strains.
+
+[Illustration: Fig. 8.]
+
+In heating the compound plates for rolling, the plate is placed in the
+furnace with the steel face down, so that the iron part gets well
+heated and the steel does not become too hot. Great care must be taken
+not to overheat the plate, and in working, many passes are given the
+plate with small closings of the rolls. The steel part of a compound
+plate is usually about one third of the full thickness of the plate.
+
+Forged steel armor, tempered in oil, is fabricated at Le Creusot,
+France, by Schneider & Co., using open-hearth steel, and forging under
+the 100 ton hammer. The ingots are cast, with twenty-five per cent.
+sinking head and are cubical in form. The porter bar is attached to a
+lug on one side of the ingot. By means of a crane with a curved jib
+which gives springiness under the hammer, the ingot is thrust into the
+heating furnace. On arriving at a good forging heat it is swung around
+to the 100 ton hammer, under which it is worked down to the required
+shape. A seventy-five ton ingot requires about eight reheatings before
+being reduced to shape. Having been reduced to shape, the plate is
+carefully annealed, then raised to a high tempering heat, and the face
+tempered in oil. It is reannealed to take out the internal strains,
+care being taken not to reduce the face hardness more than necessary.
+The Schneider process of tempering is based upon the utilization of
+the absorption of heat caused by the fusing or melting of a solid
+substance, and of the fact that so long as a solid is melting or
+dissolving in a liquid substance, the liquid cannot get appreciably
+hotter, except locally around the heating surface. The body to be
+hardened is plunged at the requisite temperature into a bath
+containing the solid melting body, or is kept under pressure in the
+solid material of low melting point until the required extraction of
+heat has taken place, more solid material being added if necessary as
+that originally present melts and dissolves.
+
+Nickel steel armor is made in a similar manner to the steel plates,
+the material used in casting the ingot being an alloy of nickel and
+steel containing between three and four per cent. of nickel.
+
+The Harvey process of making armor consists in taking an all-steel
+plate and carbonizing the face. This carbonizing process is very
+similar to the cementation process of producing steel, and by it the
+face of the plate is made high in carbon and very hard.
+
+The system invented by Sir Joseph Whitworth, of Manchester, England,
+consists in what might be called scale armor. A section of a sample of
+the armor represents four plates. The outer layer, one inch thick, is
+composed of steel of a tensile strength of 80 tons per square inch;
+the second layer, one inch thick, of steel whose tensile strength is
+40 tons per square inch; the third and fourth layers, each one-half
+inch thickness, of mild steel. The outer layer is in small squares of
+about ten inches on a side, and is fastened to the second layer by
+bolts at the corners and one in the middle of each square. The surface
+is flush. (See Fig. 9.) The end sought by the above system is to break
+up the shot by the hard steel face and to restrict any starring or
+cracking of the metal to the limit of the squares or scales struck.
+The bolts are of high carbon and are extremely hard steel.
+
+[Illustration: Fig. 9.]
+
+Armor plates must often be bent or curved to single or double
+curvature and sometimes to a warped surface to fit the form of the
+ship. There are several methods of bending plates. One method employs
+a cast iron slab of the required form, which is placed on the piston
+of a hydraulic press. The armor plate is placed face down on this
+slab, and on top of the plate are laid packing blocks of cast iron, of
+such sizes and shapes as to conform to the required curve. These
+blocks take against the upper table of the press, when the piston is
+forced up, and the hot plate is thus dished to the proper form.
+
+In the French method of bending, an anvil or bed plate of the required
+curve is used, and the armor plate is forced to take the curve by
+being hammered all over its upper surface with a specially designed
+steam hammer.
+
+The edges of the plate are trimmed by large, powerful slotting
+machines or circular saws; the latter, however, operate in exactly the
+same manner as a slotter, except that there is no return motion to the
+tool. Each tooth of the saw is but a slotting tool, and these teeth
+are, by screws, rendered capable of being nicely adjusted in the
+circumference of the saw.
+
+The plates are fastened to the hulls and backing by heavy bolts,
+varying in size according to the weight of the individual plate. For
+the 6,000 ton armored ships, these bolts are from 2.75 to 3.1 inches
+in diameter and from 18.45 to 23 inches in length. They are tapped two
+or three inches into the armor and do not go through the plate. They
+pass through wrought iron tubes in the backing and set up with cups,
+washers and nuts against the inner skin of the ship.
+
+At steel works where plates for our new navy are being manufactured,
+there are inspectors who look after the government's interests.
+Officers of the navy are detailed for this work, and their duty is to
+watch the manufacture of plates through each part of the process and
+to see that the conditions of the specifications and contract are
+complied with.
+
+The inspection and testing of armor plates consists in examining them
+for pits, scales, laminations, forging cracks, etc., in determining
+the chemical analysis of specimens taken from different parts, in
+determining the physical qualities of specimens taken longitudinally
+and transversely, and the ballistic test. Specifications for these
+different tests are constantly undergoing change, and it would be
+impossible to state, with exactness, what the requirements are or will
+be in the near future. The ballistic test is the important one, and is
+made by taking one plate of a group and subjecting it to the fire of a
+suitable gun. The other tests are simply to insure, as far as
+practicable, that all the other plates of the group are similar to and
+are capable of standing as severe a ballistic test as the test plate.
+
+The following will give an idea of the ballistic test as prescribed by
+the Bureau of Ordnance, Navy Department. The test plate, irrespective
+of its thickness, is to be backed by thirty-six inches of oak or other
+substantial wood. Near the middle region of the plate an equilateral
+triangle will be marked, each side of which will be three and one-half
+calibers long. The lower side of the triangle will be horizontal.
+Three shots will be fired, the points of impact being as near as
+possible the extremities of the triangle. The velocity of the shot
+will be such as to give the projectile sufficient energy to just pass
+through a wrought iron plate of equal thickness to the test plate, and
+through its wood backing. The velocity is calculated by the Gavre
+formula:
+
+              a
+       V squared =  --- { 3507 E squared x 2265464 e^{1.4} }
+              w
+
+[TEX: V^2 = \frac{a}{w} \{ 3507 \ E^2 \times 2265464 \ e^{1.4} \}]
+
+  V = the velocity of the projectile in feet per second.
+  a = the diameter of the projectile in inches.
+  w = the weight of the projectile in pounds.
+  E = the thickness of the backing in inches.
+  e = the thickness of the plate in inches.
+
+Using the above formula we can make out a table as follows:
+
+-------+-------+-------------+-------+-------+------+---------+
+Plate. |Backi'g| Gun, service|  w,   |  a,   |  V.  | Energy, |
+Inches.|Inches.| shot.       |Pounds.|Inches.| f. 8.| Impact. |
+       |       |             |       |       |      | f. tons.|
+-------+-------+-------------+-------+-------+------+---------+
+  6    |  36   |   6" B.L.R. |  100  |  5.96 | 1389 |  1337   |
+  7    |  36   |   6"   "    |  100  |  5.96 | 1528 |  1619   |
+  8    |  36   |   8"   "    |  250  |  7.96 | 1213 |  2550   |
+  9    |  36   |   8"   "    |  250  |  7.96 | 1308 |  2966   |
+ 10    |  36   |   8"   "    |  250  |  7.96 | 1399 |  3390   |
+ 11    |  36   |   8"   "    |  250  |  7.96 | 1489 |  3839   |
+ 12    |  36   |  10"   "    |  500  |  9.96 | 1247 |  5386   |
+ 13    |  36   |  10"   "    |  500  |  9.96 | 1315 |  5987   |
+ 14    |  36   |  10"   "    |  500  |  9.96 | 1381 |  6608   |
+ 15    |  36   |  12"   "    |  850  | 11.96 | 1215 |  8699   |
+ 16    |  36   |  12"   "    |  850  | 11.96 | 1269 |  9710   |
+ 17    |  36   |  12"   "    |  850  | 11.96 | 1332 | 10454   |
+ 18    |  36   |  12"   "    |  850  | 11.96 | 1374 | 11124   |
+ 19    |  36   |  12"   "    |  850  | 11.96 | 1425 | 11965   |
+ 20    |  36   |  12"   "    |  850  | 11.96 | 1476 | 12837   |
+-------+-------+-------------+-------+-------+------+---------+
+
+
+No projectile or fragment of the plate or projectile must get wholly
+through the plate and backing. The plate must not break up or give
+such cracks as to expose the backing, previous to the third shot.
+
+The penetration of projectiles of different forms into various styles
+of armor has been very thoroughly studied and many attempts have been
+made to bring the subject down to mathematical formulae. These formulae
+are based on several suppositions, and agree very closely with results
+obtained in actual experiments, but there are so many varying
+conditions that it is extremely doubtful if any formulae will ever be
+written that will properly express the penetration.
+
+Many different forms have been given to the heads of projectiles, as
+flat, ogival, hemispherical, conoidal, parabolic, blunt trifaced, etc.
+
+The flat headed projectile has the shape of a right cylinder, and acts
+like a punch, driving the material of the armor plate in front of it.
+These projectiles are especially valuable when firing at oblique
+armor, for they will bite or cut into the armor when striking at an
+angle of thirty degrees.
+
+The ogival head acts more as a wedge, pushing the metal aside, and
+generally will give more penetration in thick solid plates than the
+flat headed projectile. The ogival head is usually designed by using a
+radius of two calibers.
+
+The hemispherical, conoidal, parabolic and blunt trifaced all give
+more or less of the wedging effect. The blunt trifaced has all the
+good qualities of the ogival of two calibers. It bites at a slightly
+less angle, and the three faces start cracks radiating from the point
+of impact.
+
+Forged steel is the best material for armor-piercing projectiles, but
+many are made of chilled cast iron, on account of its great hardness
+and cheapness.
+
+The best weight for a projectile is found by the formula
+
+    w = d cubed (0.45 to 0.5)
+
+w being the weight in pounds, d the diameter in inches and 0.45 to 0.5
+having been determined by experiment.
+
+With a light projectile we get a flat trajectory, and accuracy at
+short ranges is increased. With a heavy projectile the resistance of
+the air has less effect and the projectile is advantageously employed
+at long ranges.
+
+In the following formulae, used in calculating the penetration of
+projectiles in rolled iron armor,
+
+  g = the force of gravity.
+  w = the weight of projectile in pounds.
+  d = the diameter of projectile in inches.
+  v = the striking velocity in feet per second.
+  P = the penetration in inches.
+
+
+Major Noble, R.A., gives
+
+              _________________
+         1.6 /      w v squared
+   P =  /\  /  ----------------
+          \/   [pi] g d 11334.4
+
+[TEX: P = \sqrt[1.6]{\frac{w \ v^2}{\pi \  g \  d \ 11334.4}}]
+
+U.S. Naval Ordnance Proving Ground uses
+
+              ________________
+        2.035/      w v squared
+   P =  /\  /  ---------------
+          \/   [pi] g d 3852.8
+
+[TEX: P = \sqrt[2.035]{\frac{w \ v^2}{\pi \  g \  d \ 3852.8}}]
+
+Col. Maitland gives
+
+            w v squared
+   P =  ------------
+        g d squared 16654.4
+
+[TEX: P = \frac{w \ v^2}{g \  d^2 \ 16654.4}]
+
+Maitland's latest formula, now used in England, is
+
+                 _
+          v     /w
+    P = ----- \/ - - 0.14 d
+        608.3    d
+
+[TEX: P = \frac{v}{608.3} \sqrt{\frac{w}{d}} - 0.14 \ d]
+
+General Froloff, Russian army, gives
+
+         w v
+    P = ------
+        d squared 576
+
+[TEX: P = \frac{w \ v}{d^2 \ 576}]
+
+for plates less than two and one-half inches thick, and
+
+         w v
+    P = ------ - 1.5
+        d squared 400
+
+[TEX: P = \frac{w \ v}{d^2 \ 400} - 1.5]
+
+for plates more than two and one-half inches thick.
+
+
+If [theta] be the angle between the path of the projectile and the
+face of the plate, then v in the above formulae becomes v sin [theta].
+
+When we come to back the plates, their power to resist penetration
+becomes greater, and our formula changes. The Gavre formula, given
+above, is used to determine the velocity necessary for a projectile to
+pass entirely through an iron plate and its wood backing.
+
+Compound and steel armor are said to give about 29 per cent. more
+resisting power than wrought iron, but in one experiment at the
+proving ground, at Annapolis, a compound plate gave over 50 per cent.
+more resisting power than wrought iron.
+
+The Italian government, after most expensive and elaborate comparative
+tests, has decided in favor of the Creusot or Schneider all-steel
+plates, and has established a plant for their manufacture at Terni,
+near Rome.
+
+The French use both steel and compound plates; the Russians, compound;
+the Germans, compound; the Swedes and Danes use both. Spain has
+adopted and accepted the Creusot plate for its new formidable armored
+vessel, the Pelayo; and China too has recently become a purchaser of
+Creusot plates.
+
+Certain general rules may be laid down for attacking armor. If the
+armor is iron, it is useless to attack with projectiles having less
+than 1,000 feet striking velocity for each caliber in thickness of
+plate. It is unadvisable to fire steel or chilled iron filled shells
+at thick armor, unless a normal hit can be made. When perforation is
+to be attempted, steel-forged armor-piercing shells, unfilled, should
+be used. They may be filled if the guns are of great power as compared
+to the armor. Steel and compound armor are not likely to be pierced by
+a single blow, but continued hammering may break up the plate, and
+that with comparatively low-powered guns.
+
+Wrought iron must be perforated, and hard armor, compound or steel,
+must be broken up. Against wrought iron plates the projectile may be
+made of chilled cast iron, but hard armor exacts for its penetration
+or destruction the use of steel, forged and tempered. Against
+unarmored ships, and against unarmored portions of ironclads, the
+value of rapid-firing guns, especially those of large caliber, can
+hardly be overestimated.
+
+The relative value of steel and compound armor is much debated, and at
+present the rivalry is great, but the weight of evidence and opinion
+seems to favor the all-steel plate. The hard face of a compound plate
+is supposed to break up the projectile, that is, make the projectile
+expend its energy on itself rather than upon the plate, and the
+backing of wrought iron is, by its greater ductility, to prevent the
+destruction of the plate. It seems probable that these two systems
+will approach each other as the development goes on. An alloy of
+nickel and steel is now attracting attention and bids fair to give
+very good results.
+
+The problem to be solved, as far as naval armor is concerned, is to
+get the greatest amount of protection with the least possible weight
+and volume, and this reduction of weight and volume must be
+accomplished, in the main, by reducing the thickness of the plates by
+increasing the resisting power of the material. In the compound plate
+great surface hardness is readily and safely attained, but it has not
+yet been definitely determined what the proper proportionate thickness
+of iron and steel is.
+
+A considerable thickness of steel is necessary to aid, by its
+stiffness, in preventing the very ductile iron from giving back to
+such an extent as to distort the steel face and thus tear or separate
+the parts of the plate. The ductile iron gives a very low resisting
+power, its duty being to hold the steel face up to its work. If now we
+substitute a soft steel plate in the place of the ductile iron, we
+will get greater resisting power, but our compound plate then becomes
+virtually an all-steel one, only differing in process of manufacture.
+The greatest faults of the compound plate are the imperfect welding of
+the parts and the lack of solidity of the iron. When fired at, the
+surface has a tendency to chip.
+
+In the all-steel plate we have the greatest resisting power
+throughout, but there are manufacturing difficulties, and surface
+hardness equal to that of the compound plate has not been obtained.
+The manufacturing difficulties are being gradually overcome, and
+artillerists are in high hopes that the requisite surface hardness
+will soon be obtained.
+
+The following may be stated as well proved:
+
+1. That steel armor promises to replace both iron and compound.
+
+2. That projectiles designed for the piercing of hard armor must be
+made of steel.
+
+3. That the larger the plate, the better it is able to absorb the
+energy of impact without injury to itself.
+
+4. That the backing must be as rigid as possible.
+
+       *       *       *       *       *
+
+[FROM ENGINEERING.]
+
+
+
+
+THE COMPRESSED AIR SYSTEM OF PARIS.
+
+
+The demand for compressed air as a motive power is constantly
+increasing in Paris; the company, according to its official reports,
+is financially prosperous, and it seems difficult to understand how it
+should continue as an actively going concern, unless it at all events
+paid its way. The central station of St. Fargeau, originally started
+on modest lines, for maintaining a uniform time by pneumatic pressure
+throughout Paris, has grown rapidly to very large proportions, though
+it has never been able to supply the demand made on it for power; and
+at the present time a second and still larger station is being
+constructed in another part of Paris. We confess that we do not
+understand why such large sums of money should continue to be spent if
+the enterprise is not commercially a sound one, nor how men of such
+eminence in the scientific world as Professor Riedler should, without
+hesitation, risk their reputation on the correctness of the system, if
+it were the idle dream of an enthusiast, as many persons--chiefly
+those interested in electric transmission--have declared it to be.
+
+[Illustration: Fig. 1.--MAP OF PARIS WITH ST. FARGEAU STATION]
+
+In describing the developments that have taken place during the last
+two years, we shall confine ourselves entirely to the details of a
+report recently made on the subject by Professor Riedler. As soon as
+it became evident that a very largely increased installation was
+necessary, it was determined that the new central station should be as
+free as possible from the defects of the first one. These defects,
+which were the natural results of the somewhat hasty development of an
+experimental system, were of several kinds. In the first place, so
+large a growth had not been contemplated, and the extensions were
+made more or less piecemeal, instead of being on a regular plan; the
+location of the central station itself was very unfavorable, both as
+regards the facilities for obtaining coal and other supplies; the cost
+of water was excessive, and the amount available, inadequate.
+
+This evil was partly remedied by elaborate arrangements for cooling
+the injection water so that it could be repeatedly used, a device
+costly and ineffective, and resulting in extravagant working, to say
+nothing of the high charges made by the Paris company for supplying
+water. To these drawbacks had to be added others of an even more
+serious character. The engines first laid down were not economical,
+and the compressors employed gave but a very inferior result; with
+each extension of the plant, the efficiency of both engines and
+compressors was increased, the most satisfactory, we believe, having
+been those supplied by the Societe Cockerill, and one of which was
+exhibited at the Paris exhibition in 1889. Still it was clearly
+recognized that much better results were possible, results which
+Professor Riedler claims have been attained and which will be embodied
+in the new installation now in progress.
+
+This central station is located on the left bank of the Seine, close
+to the fortifications, opposite Vincennes and not far from the
+terminal stations of the Orleans and the Paris, Lyons, and
+Mediterranean Railways; the plan, Fig. 1, shows the position. The
+works are separated from the river by the quay, over which a bridge
+will be constructed for the transfer of coal from the landing stages
+belonging to the company, into the works; as will be readily seen from
+the plan, it would be quite easy to run junction lines to the two
+adjacent railways, but with all the advantages given by water
+carriage, it was considered unnecessary to incur the expense. The
+river also affords a constant and unlimited water supply, so that none
+of the difficulties existing at St. Fargeau Station in imperfect
+condensation and cooling will be met with.
+
+The new installation, called the Central Station of the Quai de la
+Gare, is laid out on a very large scale, the total generating energy
+provided for being no less than 24,000 horse power; of this it is
+intended that 8,000 horse power will be in operation this year, and an
+extension of 10,000 horsepower in 1892; the power now in course of
+completion comprises four engines of 2,000 horse power each. Four
+batteries of boilers will provide steam for these engines. Figs. 2, 3,
+and 4 show the first section of the installation now in progress; the
+four groups of engines (three-cylinder condensing) are shown at 1, 2,
+3, and 4; the four groups of boilers ranged behind them at F, F; the
+feed water heaters belonging to each group at V V.
+
+[Illustration: COMPRESSED AIR STATION ON THE QUA DE LA GARE, PARIS.
+(FIG. 2,3,4)]
+
+The end of the building abuts against the Seine, and the position of
+the water conduits for inlet and discharge are indicated at C and A
+respectively. The installation, when completed, will include very
+extensive arrangements for transporting and storing coal, and the
+interior of the boiler houses will be furnished with an overhead
+system of rails and carriers for handling the coal automatically, as
+far as possible. All the principal mains and steam pipes are made in
+duplicate, not only for greater security, but in order that each set
+of engines and boilers may be connected interchangeably without delay.
+The Seine supplies an ample quantity of water, but not in a condition
+either for feeding the boilers, for condensation, or for the air
+compressors.
+
+[Illustration: THE NEW COMPRESSED AIR STATION AT PARIS. (FIG. 5, 6)]
+
+Special provisions have therefore to be made to filter the water
+efficiently before it is used. For this purpose the water is led to a
+group of four filters (see L, Fig. 4); from them it passes into the
+tanks, JJ, and is pumped into the heaters. The filters can be rapidly
+and automatically cleaned by reversing the flow of water through them.
+Figs. 5 and 6 show the general form of the type of engine adopted, as
+well as the engine house, some of the mains, etc. They are vertical
+triple-expansion engines, and are being constructed by MM. Schneider
+et Cie, of Creusot, with a guarantee of coal consumption not to exceed
+1.54 lb. per horse power per hour, with a penalty of 2,000 francs for
+every 100 grammes in excess of this limit. It is evident that with
+this restricted fuel consumption, a large margin for economy will
+exist at the new works, as compared with the St. Fargeau station,
+where the best engines cannot show anything like this result, while
+some of the earlier ones are distinctly extravagant, and the whole
+installation is handicapped with imperfect means of condensation.
+
+Moreover, according to Professor Riedler, the consumption of steam by
+the new Schneider engines will be only 5.3 kilos. per horse power and
+per hour as compared with some of the large engines requiring 9
+kilos., and the Cockerill engines--using 8 kilos. per hour, not to
+speak of the older motors that are very extravagant in the use of
+steam. The St. Fargeau station is worked under a further disadvantage.
+The constantly increasing demand from subscribers taxes the resources
+of the station to their fullest extent, so that practically there is
+no reserve power.
+
+In the new installation the work will be equally constant, but care
+will be taken always to have a sufficient reserve. Electric lighting
+will form a considerable part of the duty to be done from this
+station, and in all cases it is intended to work with accumulators, so
+that the resistance to be overcome by the engines, so far as this part
+of the duty is concerned, will be well known and uniform. The
+engineers of the Compressed Air Co., of Paris, have during the last
+five years acquired an experience which could only be attained at a
+high price and at the expense of a certain amount of failure; this
+period, it is claimed, is now passed, and in the new installation it
+is possible to put into practice all the valuable lessons learned at
+St. Fargeau, to say nothing of the more favorable natural conditions
+under which the extension is being started and the improvements in the
+compression of the air made by Mr. Popp and Professor Riedler, and to
+which we shall refer later.
+
+Chiefly in consequence of the high value of the ground, vertical
+engines were adopted at the new station; the proximity to the river
+made the foundations somewhat costly, and the risk of occasional
+floods rendered it desirable to set the level of the engine bedplates
+20 inches above the floor of the building; the foundations of the
+engines are continuous, but are quite independent of the building.
+There are three compressing cylinders in each set of engines, one
+being above each steam cylinder. Two of these are employed to compress
+the air to about 30 lb. per square inch, after which it passes into a
+receiver and is cooled; it is then admitted into the third or final
+compressing cylinder and raised to the working pressure at which it
+flows into the mains. In the illustrations, h, m, and b are the high,
+intermediate, and low pressure cylinders of one set of engines; as
+will be seen, each cylinder is on a separate frame connected by
+girders; directly above the cylinders are the two low and the one high
+pressure air cylinders, b¹, m¹, and h¹ respectively. The former
+deliver the air compressed to the first stage into the receiver, T¹
+(see Fig. 5), whence it passes into the third compression cylinder,
+and thence by a main into the cylinders, R R, which are in direct
+communication with the delivery mains; these mains terminate in the
+subway, T. The water for condensation is brought into the engine house
+by the channel, C, and the condenser pumps, a, draw direct from this
+supply; the discharge main back to the river is shown at A. The
+relative positions of the engine and boiler houses are indicated in
+Figs. 2 to 5, where F shows the end of one group of boilers; the air
+supply for the compressors is led from the central raised portion, S,
+of the roof.
+
+Professor Riedler's first experiments in improving the efficiency of
+air compressors were made with one of the Cockerill compressors in use
+at the St. Fargeau Station, and considerable difficulty attended this
+work, because the machinery was necessarily kept almost in constant
+operation. These compressors were designed by MM. Dubois and Francois,
+of Seraing. Two of their leading features were the delivery of the
+compressed air at as low a temperature as possible, and with a
+relatively high piston speed of about 400 ft. a minute. The former
+object is attained by the injection of a very fine water spray at each
+end of the air cylinder, and its rapid removal with each stroke; the
+free as well as the compressed air flows through the same passages,
+one at each end of the cylinder; the inlet valves being placed at the
+side of these passages, and the outlet or compressed air valves at the
+top, the compressed air, entering a chamber above the cylinder, common
+to both valves, and passing thence to the reservoir. The compressed
+air valves, which are seven in. in diameter, are brought back sharply
+to their seats at each stroke, by a small piston operated by
+compressed air flowing through a by-pass from the chamber. The
+illustrations published by us on page 686 of our forty-seventh volume
+show the construction of these compressors. The engravings on page 683
+of the same volume illustrate the compressors used in a somewhat older
+part of the installation; they were made by M. Blanchod, of Vevey, and
+a passing reference may be made to them. The air is admitted through
+valves in the cylinder, and is forced out through spring-loaded
+valves; water is admitted into the cylinder to cool the air.
+
+Fig. 7 indicates the modification made by Professor Riedler in one of
+the Cockerill compressors: a receiver, A, was placed under the two
+compressing cylinders, B and C. The first stage is completed in the
+large cylinder, B, the air being compressed to about 30 lb. per square
+inch; from this it is discharged into the receiver, A, through the
+pipe, B¹, where it meets with a spray injection that cools it to the
+temperature of the water. The final stage is then effected in the
+smaller cylinder, C, which, drawing the air from the receiver through
+the pipe, C¹, compresses it to about 90 lb. and delivers it through
+the pipe, d, to the mains. We hope shortly to publish drawings of this
+compressor in its final form; in its elementary stage Professor
+Riedler claims to have obtained some very remarkable results. He says
+that the waste spaces in his modification were much smaller than in
+the Cockerill compressor, while the efficiency of the apparatus was
+largely increased. The actual engine duty per horse power and per hour
+was raised, as a maximum, to 384 cubic feet of air at atmospheric
+pressure, and compressed to 90 lb. per square inch, a marked increase
+on the duty of the compressors in use at the St. Fargeau station. The
+Cockerill compressors experimented on at the same time showed a
+maximum duty of 306 cubic feet of air. A considerable advantage is
+claimed in drawing clean and cool air from the outside of the
+building, and beyond the main feature of carrying out the compression
+in two stages, Mr. Riedler appears to have shown great skill in
+introducing several minor alterations and improvements in the plant.
+
+[Illustration: EFFICIENCY CURVES FOR THREE TYPES OF COMPRESSORS. (Fig.
+8, 9, 10)]
+
+Figs. 8, 9 and 10 are diagrams showing the comparative efficiency of
+the three types of compressors at St. Fargeau--Fig. 10 being a diagram
+of the Riedler compressor--and indicate the gain derived from the
+intermediate cooling. The loss is shown to be only 12 per cent., as
+compared with a loss of 43 per cent. in a large part of the plant, and
+of 105 per cent. in the earlier compressors of the St. Gothard type.
+The table given herewith contains a summary of trials made by
+Professor Gutermuth, and are intended to show the comparative results
+of an extended trial with three kinds of compressors at St. Fargeau.
+
+  PERFORMANCES OF COMPRESSORS AT THE ST. FARGEAU CENTRAL STATION.
+
+--------------+-------+--------+------+-------+--------+--------+---------+
+              | R   p |        |  E   |       |        |        |         |
+              | e o e | Horse- |  f   |Amount |Quantity| Cubic  |         |
+Compressors.  | v f r | Power  |  f   |of Air | of Air |Feet of |Final Air|
+              | o     |Absorbed|  i   |Passing| Passing|Air per |Pressure.|
+              | l E m |   by   |  c   |through| through| Horse- |         |
+              | u n i |Compres-|  i   | Inlet | Valves | Power  |         |
+              | t g n | sors.  |  e   | Valves| per    | and per|         |
+              | i i u |        |  n   | each  | Hour.  |  Hour. |         |
+              | o n t |        |  c   |Revolu-|        |        |         |
+              | n e e |        |  y   | tion. |        |        |         |
+              | s   . |        |  .   |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+              |       |        |      | cubic |  cubic |        |lb. per  |
+1.            |       |        |      | feet  |  feet  |        |sq. in.  |
+_Sturgeon_    |       |        |      |       |        |        |         |
+_Compressor_  |  37   |   302  | .87  | 41.67 |  91,507| 261.3  | 90      |
+Diameter of   |  37   |   258  | .87  | 38.13 |  84,650| 276.1  | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+23.62 in.     |       |        |      |       |        |        |         |
+and 21.66 in.;|       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+48.63 in.     |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+2.            |       |        |      |       |        |        |         |
+_Cockerill_   | 40    |   337  | .83  | 46.61 | 111,864| 281.83 | 90      |
+_Compressor._ | 45    |   353  | .83  | 46.61 | 125,844| 302.66 | 90      |
+Diameter of   | 40    |   342  | .88  | 49.43 | 118,632| 296.65 | 90      |
+cylinder,     | 46    |   377  | .85  | 48.02 | 132,534| 298.77 | 90      |
+25.98 in.;    | 38.67 |   324  | .89  | 50.14 | 116,434| 306.19 | 90      |
+stroke,       | 38.5  |   337  | .89  | 50.14 | 115,818| 294.18 | 90      |
+47.24 in.     | 38.6  |   329  | .91  | 50.84 | 117,740| 305.13 | 90      |
+              |       |        |      |       |        |        |         |
+              |       |        |      |       |        |        |         |
+3.            |       |        |      |       |        |        |         |
+_Riedler_     | 52    |   615  | .985 | 77.34 | 241,300| 353.50 | 90      |
+_Compressor._ | 60    |   709  | .985 | 76.98 | 277,128| 353.50 | 90      |
+Diameter of   | 38    |   422  | .985 | 77.34 | 176,330| 376.12 | 90      |
+low-pressure  | 39    |   424  | .985 | 77.34 | 181,030| 384.60 | 90      |
+cylinder,     |       |        |      |       |        |        |         |
+42.91 in.;    |       |        |      |       |        |        |         |
+diameter of   |       |        |      |       |        |        |         |
+high-pressure |       |        |      |       |        |        |         |
+cylinder,     |       |        |      |       |        |        |         |
+26.38 in.;    |       |        |      |       |        |        |         |
+stroke,       |       |        |      |       |        |        |         |
+47.24 in.     |       |        |      |       |        |        |         |
+--------------+-------+--------+------+-------+--------+--------+---------+
+
+
+The results thus obtained were so satisfactory that the designs were
+prepared for the great compressors to be operated at the new central
+station on the Quai de la Gare by the 2,000 horse power engines.
+
+The transmission of the compressed air through the mains is
+unavoidably attended with a certain percentage of loss, which, of
+course, increases with the length of the transmission, the presence of
+leakage at the joints, etc. Professor Riedler has devoted considerable
+time to the investigation of this source of waste, and we shall
+presently refer to the results he has recorded; in the first place,
+however, we propose to consider what he has to say on the subject of
+utilizing the air at the points of delivery, and the means employed
+for obtaining a relatively high efficiency of the motor.
+
+In the earliest stages of the Popp system in Paris it was recognized
+that no good results could be obtained if the air were allowed to
+expand direct into the motor; not only did the formation of ice due to
+the expansion of the air rapidly accumulate and choke the exhaust, but
+the percentage of useful work obtained, compared with that put into
+the air at the central station, was so small as to render commercial
+results hopeless. The practice of heating the air before admitting it
+to the motor is quite old, but until a few years ago it never seems to
+have been properly carried out; in several mining installations where
+this motive power had been long used, more or less imperfect attempts
+had been made to heat the air; in one instance only, recorded by
+Professor Riedler, was an efficient means employed. In this case a
+spray of boiling water was injected into the cylinder and mixed with
+the air at each stroke, with the result that a very marked economy was
+obtained.
+
+After a number of experiments, Mr. Popp arrived at the conclusion that
+the simplest mode of heating, if not the most efficient, was at all
+events the most suitable, as it was a matter of the first importance
+that subscribers should not be troubled with the charge of any
+apparatus involving complication or careful management; he therefore
+adopted a simple form of cast iron stove lined with fireclay, heated
+either by a gas jet or by a small coke fire. It was found that this
+apparatus, crude as it was, answered the desired purpose, until some
+better arrangement was perfected, and the type was accordingly adopted
+throughout the whole system. It was quite recognized that this method
+still left much to be desired, and the economy resulting from the use
+of an improved form was very marked.
+
+From a large number of trials very carefully carried out by Professor
+Gutermuth, it was found that more than 70 per cent. of the total
+number of calories in the fuel employed was absorbed by the air and
+transformed into useful work. Whether gas or coal be employed as the
+fuel, the amount required is so small as to be scarcely worth
+consideration; according to the experiments carried out, it does not
+exceed 0.09 kilo. per horse power and per hour, but it is scarcely to
+be expected that in regular practice this quantity is not largely
+exceeded. Professor Weyrauch has also carefully investigated this part
+of the subject and fully confirms, if he, indeed, does not go beyond
+Professor Gutermuth. He claims that the efficiency of fuel consumed in
+this way is six times greater than when burnt under a boiler to
+generate steam. He goes so far as to assert that with a good method of
+heating the air, not only can all the losses due to the production and
+the transmission of the compressed air be made good, but also that it
+will actually contain more useful energy at the motor than was
+expended at the central station in compressing it.
+
+According to Professor Riedler, from 15 to 20 per cent. above the
+power at the central station can be obtained by means at the disposal
+of the power users, and it has been shown by experiment that by
+heating the air to 250 deg. Cent. an increased efficiency of 30 per
+cent. can be obtained. Better results than those heretofore obtained
+may, therefore, be confidently expected with a more perfect and
+economical application of the fuel in heating the air, and a better
+means of regulation in admitting it to the motors. In his report
+Professor Riedler indicates a method by the use of which he considers
+considerable advantages may be secured. This is the heating the air in
+two stages instead of at one operation, and passing it through two
+motors, to the first of which the air is admitted heated only to a
+moderate extent; the exhaust from this motor then passes into a second
+heater and thence into the second motor. A series of experiments with
+this arrangement were recently carried out.
+
+The consumption of air per brake horse power was reduced from 812
+cubic feet per hour, a favorable duty in the single motor, to 720, and
+in the best result to 646 cubic feet with the two motors and double
+heaters. It should be added that these trials were carried out with
+steam engines but ill adapted for the purpose. It is to be regretted
+that the experiments of Professor Riedler could not have been
+conducted with more perfect appliances, but it must be borne in mind
+that the utilization of compressed air, especially as regards the
+motors, is still in a very imperfect stage, and that a great deal
+remains to be done before the maximum power available at the motor can
+be obtained. Investigations in this direction for a considerable time
+to come must be directed, therefore, toward improving the design and
+construction of the motors and the treatment of the air at the point
+of delivery into the engine.
+
+A large number of motors in use among the subscribers to the
+Compressed Air Company, of Paris, are rotary engines developing one
+horse power and less, and these in the early times of the industry
+were extravagant in their consumption, to a very high degree. To some
+extent this condition of things has been improved, chiefly by the
+addition of better regulating valves to control the air admission.
+
+As altered, the two horse power rotary motors, when employed as cold
+air engines, a method often desired in special industries, consume
+1,059 cubic feet per hour and per indicated horse power; with a
+moderate degree of heating, say to 50 deg. Cent., this consumption
+falls to 847 cubic feet. The efficiency of this type of rotary motors
+with air heated to 50 deg. may now be assumed at 43 per cent., not a
+very economical result, it is true, and one that may be largely
+improved, yet it is evident that with such an efficiency the use of
+small motors in many industries becomes possible, while in cases where
+it is necessary to have a constant supply of cold air, economy ceases
+to be a matter of the first importance.
+
+Some useful results were obtained with compressed air used in crank
+engines; it is to be regretted that with this, also, apologies have to
+be made for the imperfect design and construction; they were old steam
+engines, some of those of two horse power losing from 25 to 30 per
+cent. by their own friction; some of the others tried, however, were
+far better, a newer type losing only from 8 to 10 per cent., while the
+80 horse power referred to below showed an efficiency of 91 per cent.
+From these trials Prof. Riedler deduces--assuming 85 per cent.
+efficiency--a consumption of 611, 752, and 720 cubic feet per brake
+horse power. It is very evident from the foregoing that the Compressed
+Air Company, of Paris, will never do itself justice until as much
+thought and care has been devoted to the economical use of the motive
+power as has been expended in the means of producing it, and Professor
+Riedler's recent investigations should be especially useful in this
+respect. The question has indeed attracted the attention of more than
+one manufacturer, and reference is made to a particular type of small
+rotary motors which are being constructed by MM. Riedinger & Co., and
+which is stated have given very excellent results. These engines were
+specially used for working sewing machines and developed on the brake
+an efficiency of 34.07 and 51.63 foot pounds per second. Trials were
+made with a half horse power variable expansion Riedinger engine.
+
+
+  TRIALS OF A SMALL ROTARY RIEDINGER ENGINE.
+ ______________________________________________________________
+                                               |       |
+  Number of trials.                            |   I.  |   II.
+ ______________________________________________|_______|_______
+                                               |       |
+ Initial air pressure.     lb. per square inch |    86 | 71.8
+      "      temperature.           deg. Cent. |   +12 |  +170
+ Ft. pounds per second  measured on the brake. | 51.63 | 34.07
+ Revolutions per minute.                       |   384 |  300
+ Consumption of air for one horse power per    |       |
+    hour.                                      | 1,377 |  988
+ ______________________________________________|_______|_______
+
+
+  TRIALS OF A 0.5 HORSE POWER RIEDINGER ROTARY ENGINE.
+ _____________________________________________________________________
+                                           |      |      |      |
+  Number of trials.                        |  I.  |  II. | III. |  IV.
+ __________________________________________|______|______|______|_____
+                                           |      |      |      |
+ Initial pressure of air.  lb. per sq. in. |   54 | 69.7 |   85 | 71.8
+      "  temperature of air.    deg. Cent. |  170 |  180 |  198 |    8
+ Final        "        "            "      |   25 |   20 |  ... |   25
+ Revolutions per minute.                   |  335 |  350 |  310 |  243
+ Foot pounds per second measured on        |      |      |      |
+    brake.                                 |  271 |  477 |  376 |  316
+ Consumption of air per horse power        |      |      |      |
+    and per hour.                          |  883 |  791 |  900 |1,148
+ __________________________________________|______|______|______|______
+
+  TRIAL OF AN 80 HORSE POWER (NOMINAL) FARCOT STEAM ENGINE.
+ ___________________________________________________________________
+                  | R p  |      |                  |
+                  | e e  | I    |                  | Consumption of
+                  | v r  | n    |   Temperature    |  air per horse
+                  | o    | d h p|      of air.     |  power and per
+                  | l m  | i o o|                  |      hour.
+                  | u i  | c r w|__________________|________________
+                  | t n  | a s e|         |        |       |
+    Motor.        | i u  | t e r|Admission|Exhaust.|Nominal| Brake
+                  | o t  | e   .|         |        | horse | horse
+                  | n e  | d    |         |        | power.| power.
+ _________________|_s_.__|______|_________|________|_______|________
+                  |      |      |  deg. C | deg. C |       |
+ Nominal 80 horse | 54.3 | 72.3 |    129  |   21   |  469  |  517
+ power single     | 54.3 | 72.3 |    152  |   29   |  437  |  475
+ cylinder Farcot  | 54.0 | 72.3 |    160  |   35   |  424  |  465
+ engine.          | 40   | 65.0 |    170  |   49   |  438  |  477
+ _________________|______|______|_________|________|_______|________
+
+
+These motors, it may be assumed, represent the best practice that has
+been obtained up to the present time in the construction of compressed
+air motors; with the smallest of them, indicating about one-tenth of a
+horse power, the consumption of air, when admitted cold, was 1377
+cubic feet and 988 cubic feet when the air was heated before
+admission. The half horse power engine consumed 1148 cubic feet of
+cold air, and of heated air 791 cubic feet per horse power and per
+hour. It should be mentioned that these, the most valuable and
+suggestive of all the trials carried out by Professor Riedler, were
+conducted with the greatest care, two distinct modes of measuring the
+air supplied being followed on two occasions for each test; it may
+therefore be considered that the results given are absolutely correct.
+The trials were made with an old single cylinder Farcot engine,
+nominally of 80 horse power, but indicating over 72.3. With this
+engine the consumption of air varied from 465 to 517 cubic feet, the
+larger consumption being due to the lower temperature (129 deg. Cent.)
+to which the air was raised before admission; in the most economical
+result the temperature was 160 deg. Cent. The volumes of air referred
+to are, of course, in all cases taken at atmospheric pressure.
+
+Among the important losses that have to be reckoned with in every
+system of distributing motive power from a central station--whether by
+steam or by electricity, water, or compressed air--losses must occur
+in the mains by which the power generated is transferred from the
+point of production to that of consumption. In the case we are now
+considering very careful tests were conducted in 1889 by Professor
+Kennedy, to whose report we have already referred. Since that time
+important changes have been made by the Compressed Air Company, at
+Paris, in the details of distribution, and on this account the later
+investigations of Professor Riedler on the losses due to this cause
+are of special interest.
+
+Before its admission into the mains a certain loss occurs at the St.
+Fargeau station, in the large reservoirs to which the air is delivered
+from the compressors. This question of preliminary storage was one
+that received considerable attention when the designs of the new
+station on the Quai de la Gare were being considered. It was intended
+to construct very large receivers in the basement of the station, and
+the foundations for these were even commenced. It was decided,
+however, that for the 10,000 horse power which is to form the first
+section of the new station, and for which the complete system of mains
+has already been laid down, storage reservoirs would be unnecessary,
+and a saving both in first cost and subsequent loss of air would be
+effected. The length of mains of 19.69 in. diameter is so considerable
+that they will contain at all times a sufficient reserve of air to
+prevent any irregularities in pressure at the motors.
+
+With reference to these mains it may be mentioned that, unlike the
+11.81 in. conductors of the St. Fargeau system, of which 17 kilometers
+are laid in the Paris subways, the new mains are entirely laid in the
+streets, it having been found impossible to make room for these large
+pipes in the subways already crowded with telegraph and telephone
+wires, water mains, etc.
+
+Professor Riedler investigated the two causes of loss in the
+mains--leakage and resistance. It was superficially evident that the
+mains of the old system were so well laid, and the joints so well
+designed, that the loss from leakage was never a serious one. In
+order, however, to ascertain the amount accurately, a series of
+careful experiments were carried out by Professor Gutermuth with the
+11.81 in. mains of the St. Fargeau system.
+
+
+  EXPERIMENTS ON LEAKAGE IN MAINS.
+
+---------------------------------------------------------------------
+| |                 |         |               |             | L P A |
+| |                 |         | Air Pressure  |   Loss of   | o e i |
+| |                 |         |  in Mains.    |  Pressure.  | s r r |
+| |                 |         |---------------|-------------| s     |
+| |                 |         |  B    |       |      |      |   C D |
+| |System of Mains  | Length. |  e   T|       |      |      | o e e |
+|N|    Tried.       |         |  g   r|  At   |      |      | f n l |
+|u|                 |         |A i o i| End   |During| Per  |   t i |
+|m|                 |         |t n f a|  of   |Trials|Hour. | A . v |
+|b|                 |         |  n   l|Trials.|      |      | i   e |
+|e|                 |         |  i   s|       |      |      | r o r |
+|r|                 |         |  n   .|       |      |      |   f e |
+| |                 |         |  g    |       |      |      |     d |
+--+-----------------+---------+-------+-------+------+------+-------|
+| |                 | yards.  | atm.  |  atm. |      |      |       |
+|1|Southern reseau  |         |       |       |      |      |       |
+| | to Place de la  |         |       |       |      |      |       |
+| | Concorde.       |  9,980  | 6.5   |  6.0  | 0.5  | 1.5  |  3    |
+|2| Total reseau    | 18,500  | 6.9   |  5.9  | 1.0  | 1.5  |  6.3  |
+|3|To Place de      |         |       |       |      |      |       |
+| | la Concorde     |  9,980  | 7.0   |  6.43 | 0.57 | 0.75 |  2.16 |
+|4|Total reseau     | 18,500  | 6.7   |  5.28 | 0.88 | 1.32 |  5.5  |
+|5|Northern reseau  |         |       |       |      |      |       |
+| | to Rue de Belle-|         |       |       |      |      |       |
+| | ville.          |  1,530  | 6.0   |  5.0  | 1.0  | 0.6  |  2.3  |
+|6|To the Rue des   |         |       |       |      |      |       |
+| | Pyrenees.       |    600  | 6.1   |  3.7  | 2.4  | 0.56 |  2.2  |
+---------------------------------------------------------------------
+
+
+These trials refer to the mains running from the St. Fargeau station
+to the Place de la Concorde, a length of 9.142 kilometers; to the
+whole system of mains, 16.5 kilometers; to the northern mains running
+from St. Fargeau to the Rue de Belleville, 1.4 kilometers; and from
+St. Fargeau to the Rue des Pyrenees, 6.5 kilometers. It will be seen
+from the figures given in the table that the actual loss is small, and
+it is stated that this is due chiefly to the elastic joint employed
+throughout the system, excepting in the Rue de Belleville, where rigid
+couplings are used, and continual trouble is experienced from loss by
+leakage. In all cases the losses given are the maximum, which only
+occur under the most unfavorable conditions.
+
+It was found, during the first, second, and fourth tests, that
+considerable leakage occurred between the St. Fargeau central station
+and the Rue de Belleville. During the trials two and four, an
+uncertain amount of loss occurred from the consumption of air required
+to work the pneumatic clocks, and also motors in the circuit, that
+could not be stopped. The tests two and four include all losses in the
+service pipes, as well as the mains.
+
+The production of compressed air at the central station is assumed at
+30,000 cubic feet per hour (atmospheric pressure), and in all cases
+the loss in the mains is taken as a percentage of the total
+production.
+
+The losses due to resistance in the mains were also examined with
+great care, over independent sections, as well as through the complete
+_reseau_. During the early part of these trials, an unusual and
+excessive loss was recorded, the cause of which could not be at first
+ascertained. At intervals along these mains are placed a number of
+water reservoirs which receive the water injected into the mains; in
+addition to these the direct flow of the air is interrupted by
+numerous siphons, the stop valves to branches, etc. Investigation
+showed that the presence of these reservoirs created considerable
+resistance on account of an increased and subsequently reduced
+section. The exact loss from this cause was, therefore, carefully
+measured, as well as the losses existing in the mains not so
+interrupted. The results show that the loss by expansion at one
+reservoir, when the speed of the air flow was 23 ft. per second, was
+equal to 0.15 atmosphere; with a speed of 29 ft. 6 in. per second, it
+amounted to 0.2 atmosphere.
+
+Therefore, the presence of five such reservoirs would cause a loss in
+pressure equal to one atmosphere. This very undesirable arrangement is
+not repeated in the new system, the sumphs being connected in such a
+way as not to modify the section of the tube, nor consequently the
+pressure of the air. The presence of the siphons and stop valves did
+not seem to affect the pressure to any measurable extent. The
+following table contains a list of the more important mains tested,
+and it may be mentioned that the resistance, due to the reservoirs,
+was at first partially included. The trials were carried out while the
+mains were not being drawn upon by subscribers.
+
+
+-----------------------------------------------------------------------
+                                                   |            |
+Section of Mains Tested.                           |  Length.   |No. of
+                                                   |            |Tests.
+                                                   |            |
+---------------------------------------------------+------------+------
+                                                   |  yards.    |
+From the central station to the end of reseau and  |            |
+  back to central station by return circuit        |  18,100    |   7
+From the central station to the Rue Fontaine au    |\ 14,600    |/  3
+  Roi                                              |/  9,900    |\  4
+From the central station to the Rue de la          |            |
+  Charonne                                         |   9,490    |   5
+From the Rue de la Charonne to Fontaine au         |            |
+  Roi                                              |   4,770    |   3
+From the central station to the Avenue de la       |            |
+  Republique                                       |   1,860    |   8
+Various trials on different lengths of mains       |770 to 8,000|  11
+-----------------------------------------------------------------------
+
+
+Over the whole system of 16.5 kilometers, which was also tested when
+no air was being taken off, there were four reservoirs of considerable
+size, and which offered a large resistance with a corresponding loss
+of pressure; on the line there were also 23 siphons and 42 stop
+valves.
+
+These trials were repeated several times to secure accuracy, and the
+speed of the air was brought to 49 ft. a second. The results obtained
+in one of these trials may be taken as an example. The main between
+the Rue St. Fargeau and the Fontaine au Roi, on which there are no
+collecting reservoirs, but three siphons and eight stop valves, gave,
+with an average speed of 21 ft. 3 in., a loss in pressure of 0.05
+atmosphere for each kilometer of main.
+
+From these experiments it would appear that, assuming a speed of 21
+ft. per second, a loss in pressure of one atmosphere would correspond
+to a distance of 20 kilometers; that is to say, a central station
+could extend its mains on all sides with a radius of 20 kilometers,
+and the motors at the ends of the lines would receive the air at a
+pressure 15 lb. less than at the central station. Professor Riedler
+states that as an actually measured result, the velocity of the air
+through the mains of the St. Fargeau system is 19 ft. 8 in. per
+second, and that the loss in pressure per kilometer is 0.07
+atmosphere. From this it follows that including the resistances due to
+the four reservoirs, and other obstructions actually existing, an
+allowance of one atmosphere loss on a 14 kilometer radius is ample. By
+increasing the initial pressure of the air, much better results can be
+obtained, and future attention in practice should be devoted to this
+point. The amount of work required to compress air does not increase
+in the same ratio as the pressure, and for this reason considerable
+economy can be effected at the first stage, and the loss in the mains
+will be reduced.
+
+Passing to another point of the same subject, Professor Riedler
+considers the best dimensions that should be given to the mains.
+Resistance decreases with an increase in the diameter of these and in
+direct ratio to their diameter; for this reason--still assuming a
+pressure corresponding to a velocity of 20 ft. per second--with a fall
+of one atmosphere, a length of 40 kilometers could be succesfully
+worked.
+
+The mains of the new _reseau_ for the Quai de la Gare station are
+19.69 in. in diameter; they are built up of steel plates riveted, and
+this Professor Riedler considers to have been a serious error on
+account of the extra resistance offered by the large number of rivet
+heads.
+
+The following may be taken as a brief summary of Professor Riedler's
+conclusions: Recent improvements in central station practice have
+resulted in an increased efficiency of about 30 per cent. in the
+compressors, but this benefit can only be realized when the new
+station is in operation. That the small and very imperfect air engines
+in use on the system give an efficiency of 50 per cent., while with
+ordinary steam engines driven by air an efficiency of 80 per cent. can
+be reached with a very small expenditure of fuel for heating the air
+before admitting it into the motor. That special attention should be
+given to the improvement of air engines, and that with increased
+initial pressures at the central station the distance of the
+transmission can be very considerably augmented. Finally, Professor
+Riedler claims that power can be transmitted by compressed air more
+conveniently and more economically than by any other means.
+
+       *       *       *       *       *
+
+[Continued from SUPPLEMENT, No. 802, page 12810.]
+
+
+
+
+THE BUILDERS OF THE STEAM ENGINE--THE FOUNDERS OF MODERN INDUSTRIES
+AND NATIONS.[1]
+
+[Footnote 1: An address delivered at the Centennial Celebration of the
+American Patent System, Washington, April, 1891.]
+
+By Dr. R.H. THURSTON, Director of Sibley College, Cornell University.
+
+
+Papin, Worcester, Savery, were the authors of the period of
+application of the power of steam to useful work in our later days.
+The world was, in their time, just waking into a new life under the
+stimulus of a new freedom that, from the time of Shakespeare, of
+Newton, and of Gilbert, the physicist, has steadily become wider,
+higher, and more fruitful year by year. All the modern sciences and
+all the modern arts had their reawakening with the seventeenth
+century. Every aspect of freedom for humanity came into view in those
+days of a new birth. Both the possibility of the introduction of new
+sciences and of new arts and the power of utilizing all new
+intellectual and physical forces came together. The steam engine could
+not earlier have taken form, and, taking form, it could not have
+promoted the advance of civilization in the earlier centuries. The
+invention becoming possible of development and application, the
+promotion of the arts and of all forms of human activity became a
+possible consequence of its final successful introduction into the
+rude arts that it was to so effectively promote and improve.
+
+But the work of these inventors was in itself but little more
+important than that of the Greek inventor of the steam aelopile, for
+each brought forward a machine which was, from a business point of
+view, utterly impracticable, and which, in each case, only served to
+show that a better device might prove useful and lead the way to its
+introduction. The merit of the inventors of the eighteenth century was
+that they were _able_ to lead the way, to point out the path to
+success, to furnish evidence of the value of the coming, crowning
+invention. The "fire engines," as they were then called, of these now
+famous men were merely contrivances by the use of which the pressure
+of confined steam of high tension could be brought to act on the
+surface of a mass of confined water, forcing it downward into pipes
+through which it was led off and upward to a higher level; and thus a
+mine could be drained, ineffectively and expensively to be sure, but
+vastly more satisfactorily than by the animal power of the time. The
+machine of Savery was the best of all; but that was only a somewhat
+improved and manageable rearrangement of the engines of Papin and
+Worcester. And, after all, Papin, the greatest man of science perhaps
+of his time, died in poverty; Worcester languished in prison his whole
+life, and the later efforts of his widow brought nothing by way of a
+return for his invention; nor did either they or their successor,
+Morland, make the introduction of the engine either general or
+remunerative.
+
+Savery, coming on the stage at more nearly the right time to seize
+upon an opportunity, gained more than either of his predecessors; but
+we have no evidence that he ever acquired any large compensation or
+met with any remarkable business success in the introduction of the
+rude engine which bore his name; nor did Desaguliers, the great
+philosopher, or even Smeaton, the great engineer, of the later years
+of that century, make any great success of it. It was reserved for
+Watt to reap the harvest. But, though he so effectively reaped where
+his predecessors had sown, Watt is not the greatest of the inventors
+of the steam engine, if we rate his standing by the magnitude of the
+improvement which marked his reconstruction of the engine.
+
+It was NEWCOMEN who made the modern steam engine.
+
+When Newcomen came forward the labors of Worcester in Great Britain
+had sufficed to attract the attention of all intelligent men to the
+character of the problem to be solved, and to convince them of its
+importance and promise. The work of Savery had shown the
+practicability of the solution of the problem, both in mechanics and
+finance. He succeeded, though under great disadvantages and
+comparatively inefficiently. Once the task had been performed, though
+ever so rudely, the rest came easily and promptly. The defects of the
+Savery system were at once recognized; its great wastes of heat and of
+steam were noted, and the fact that they were inherent in the system
+itself was perceived. A complete change of type of machine was
+obviously requisite; it was this which constituted the greatest
+invention in the whole history of the steam engine, from Hero's time
+to our own; and to Newcomen we owe more than to any other man who ever
+lived, the value of the invention itself being considered, and the
+importance of the services of its introducer being left out of
+consideration. No such complete and vital improvement and modification
+of the machine has ever been effected by any other man, Watt and
+Corliss not excepted. Newcomen and his comrade Calley--we do not know
+how the honors should be divided--produced the modern steam engine.
+Its predecessor, the Savery engine, had been a mere steam "squirt."
+Newcomen constructed an engine. Savery built a simple combination of
+cylindrical or ellipsoidal vessels which wastefully and at once
+performed all the several offices of engine, pump, condenser, and
+boiler; Newcomen divided the several elements among as many parts,
+each especially adapted to the performance of its task in the most
+effective manner--the condenser excepted; for that was Watt's
+principal invention--and thus produced the first steam engine in the
+modern sense of that term.
+
+It was Newcomen, not Watt, who gave us the train of mechanism that we
+now call the steam engine. It is to Newcomen, rather than Watt, that
+we owe the highest honors as an inventor in this series of the most
+important of all the products of the inventive genius of mankind.
+Newcomen brought into existence a new, the modern, type of engine, and
+effected the greatest revolution that has been recorded in the history
+of the arts. Without Newcomen, there might have been no Watt; without
+Watt, there very possibly may not even yet have been brought into
+existence that giant of our time, whose mighty powers are employed
+more effectively than ever those of Aladdin's genii, in building
+palaces, in transporting men and material, in doing the work of the
+whole world; promoting the welfare of the race, in a single century,
+more than had all the forces of matter and mind together in the whole
+previous history of the world. Newcomen laid down a foundation beneath
+our whole economic system, out of sight, almost, but the essential
+base, nevertheless, on which Watt and his successors have carried up
+the great superstructure which seems to us to-day so imposing; which
+is so tremendous in magnitude, importance, and result. If to any one
+man could be assigned the credit, it is Newcomen who is to be
+considered the inventor of the steam engine.
+
+James Watt, indisputably the great inventor that he was, found the
+steam engine ready to his hand, applied himself to its improvement,
+and made it substantially what it is to-day. His most important work,
+the most unique service performed by him, was, however, that of its
+adaptation and introduction to do the work of the world. James Watt
+was the inaugurator of the era of refinement of the machine already
+invented, and the greatest of its builders and distributors. His
+inventions were all directed to the improvement of its details, and
+his labors to its introduction and its application to the myriad tasks
+awaiting it. By the hands of Watt it was made to pump water, to spin,
+to weave, to drive every mill; and he it was who gave it the form
+demanded by Stephenson, by Fulton, by the whole industrial world, for
+use on railway and steamboat, and in mill and factory, throughout the
+civilized countries of the globe. It was this great mechanic who
+showed how it might be made to do its work with least expense, with
+highest efficiency, with greatest regularity, with utmost
+concentration of power.
+
+The grand secret of his success was historical and economic, as much
+as scientific and mechanical. He brought out his inventions just when
+the world was economically and historically ready for them. The age of
+authority was past, that of freedom was come; the period of political
+and ecclesiastical tyranny was gone by, and that of the spontaneous
+development of man was arrived. The great invention was offered to a
+world ready and needing it, and, more than all, competent, for the
+first time in history, to make and use it.
+
+James Watt was himself a product of the modern scientific spirit. He
+was a man so constituted mentally that he could apply scientific
+methods to problems which his logical and clairvoyant mind could
+readily and exactly formulate the instant he was led to their
+consideration in the natural course of his progress. He was the ideal
+great inventor and mechanic. With inventive genius he combined strong
+common sense--not always a quality distinguishing the inventor--clear
+perception, breadth of view, and scientific method and spirit in the
+treatment of every question. His natural talent was re-enforced by an
+experience and an environment which led him to develop these ways and
+this mental habit. His trade was that of an instrument maker, his
+position was that of custodian and repairer of the apparatus of
+Glasgow University. He had for his daily companions and stimulus the
+great men and ozonized atmosphere of that famous institution. He kept
+pace with advancing science, and was imbued, both naturally and
+through contact with its promoters, with that ambition and those
+aspirations which are the life element of all progress, whether
+scientific or other. He was aware of the nature of the problems
+seeking solution at the time, and familiar with the state of his own
+art and that of the great mechanicians about him. Everything was
+favorable to his progress, so soon as he should be given an
+opportunity to take a step in advance and to come into sight at the
+front. The man and the time were both ready, and all conditions,
+internal and external, social and personal, were favorable to his
+development.
+
+The invention upon which Watt was to improve was at his hand. A word
+in regard to its status at the moment will throw some light upon that
+of Watt and his creation. Newcomen had, as we have seen, produced the
+modern type of steam engine as an original and wholly novel invention.
+But this machine, marvelous as an advance upon pre-existing forms of
+the steam engine, was still, as seen in the light of recent knowledge
+and experience, exceedingly defective. The purpose of a steam engine
+is to convert into usefully applicable power the hidden energy of
+fuel, stored ages ago in the earth, by transformation, through the
+action of vegetation, from the original form, the heat of the sun,
+into an available form for reconversion, through thermodynamic
+operations. In this process of reconversion, whatever the nature of
+the machine used in the operation, there are invariably wastes, both
+of heat required for conversion into power and of the power thus
+produced. That machine which effects the most complete transmutation
+of the heat supplied it into mechanical power, which wastes the least
+amount of heat supplied and of power produced, is the best engine, and
+constitutes an advance over every other.
+
+It was this reduction of wastes that made the Newcomen engine so much
+superior to that of Savery. The latter was by far the simpler and less
+costly construction; but its enormous losses, both of heat and of
+power, mainly the former, however, made it an extravagant expenditure
+of money to buy and use it. The Newcomen engine, costly and cumbrous,
+comparatively, nevertheless wasted so much less heat and steam and
+fuel that no one could afford to buy the cheaper machine. Before
+considering what Watt accomplished, we may find it profitable to
+examine into the nature of the wastes which characterized this later
+and better machine on which he effected his improvements.
+
+The Newcomen engine consisted of a steam boiler, a steam cylinder, a
+beam and a set of pumps. By making the boiler do its work separately,
+the engine acting independently, and the pumps as a detached portion
+of the mechanism, this inventor had reduced to an enormous extent
+those wastes of heat and of steam and of fuel which were unavoidable
+in the older machines in which all these parts were represented by a
+single vessel, or by two at most, in each element. In the Savery
+engine, the steam entering first heated up the interior of the working
+vessel to its own temperature, and held it at that temperature in
+spite of the cooling influence of the water present. This consumed
+large quantities of heat. It then was compelled to surrender probably
+much greater quantities still to the water itself, coming in direct
+contact as it did with its surface. If the water was agitated, either
+by the currents produced during its ingress or by the impact of the
+steam entering the vessel, this heating action penetrated to
+considerable depths and perhaps even warmed the whole mass very far
+above its initial temperature. This constituted another and a very
+serious loss. Then, again, as the water was gradually driven out of
+the containing vessel by the steam pressing on its surface, new
+portions of the vessel and new masses of water were continually
+brought in contact with the hot steam, taking its full temperature,
+and thus, often, probably, finally heating the whole mass of the
+forcing vessel, and a large proportion of the water as well, up to the
+temperature, approximately at least, of the steam itself. Thus in many
+instances, if not always, vastly more heat and steam were wasted, in
+this undesirable heating of water and forcing vessel, than were
+usefully employed in the legitimate work of raising the water to a
+higher level. In fact, in some cases in which these quantities were
+measured, the wastes were one hundred times as much as the work done.
+One per cent. of the heat supplied did the work; while ninety-nine per
+cent. was thrown away. One dollar or one shilling expended for fuel to
+do the work was accompanied by an expenditure of ninety-nine dollars
+or shillings thrown away, because of the imperfections of the system
+and machine. The whole history of the development of the steam engine
+has been one of gradual reduction of these wastes; until to-day, our
+best engines only compel us to spend five dollars for wastes to each
+dollar paid out for useful work. A business man would think that amply
+extravagant, however, and the man of science is continually seeking
+methods of evading these losses, a large proportion of which are now
+apparently unavoidable in heat engines, by finding some new system of
+heat and energy transformation.
+
+Watt was the instrument maker and repairer at Glasgow University in
+the year 1763. His companions were, among others, the professors of
+natural philosophy and of mathematics in the university. Their
+conversation and their frequent presentation of practical and
+scientific questions and problems stimulated his naturally inquiring
+and inventive mind to the pursuit of a thousand interesting and
+promising schemes for the improvement of existing methods and
+machinery. Dr. Robison, then a student, suggested the invention of a
+steam carriage for use on common roads, and the young mechanician at
+once began experiments that, resulting in nothing at the time, were
+nevertheless continued, in one or another form, until all modern
+applications of steam came into view. Dr. Black taught Watt chemistry,
+then a newly constructed science, and led him on to the discovery,
+finally made by them independently, of the fact and the magnitude of
+the latent heat of steam; the discovery coming of a series of
+scientifically planned and accurately conducted investigations, such
+as the man of science of to-day would deem creditable. The treatises
+of Desaguliers and others on physics gave Watt a knowledge of that
+domain of natural phenomena which stood him in good stead later, when
+he attempted to apply its principles to the reduction of the wastes of
+the steam engine.
+
+It was while at Glasgow University, working under such influences and
+in such an atmosphere of intellectual activity, that the accident of
+the Newcomen model engine needing repair brought to the mind of Watt
+the opportunity which, availed of at once, made him famous and gave
+the world its greatest aid, its most powerful servant. The observing
+mind of the great mechanic immediately noted its defects, sought their
+causes, found their remedy. He discovered, at once, that the quantity
+of steam entering the cylinder of the little engine has four times the
+volume of the cylinder receiving it: in other words, three-fourths of
+that steam must be condensed immediately on entrance. This meant,
+evidently, that only one-fourth of the steam supplied was utilized,
+and even then inefficiently, in doing its work. The reason of this was
+as easily seen, immediately the fact was revealed. As Watt himself
+expressed it, the causes of this loss, causes which would obviously be
+exaggerated in a small engine, were: "First, the dissipation of heat
+by the cylinder itself, which was of brass and both a good conductor
+and a good radiator. Secondly, the loss of heat consequent upon the
+necessity of cooling down the cylinder at every stroke in producing
+the vacuum. Thirdly, the loss of power due to the pressure of vapor
+beneath the piston, which was a consequence of the imperfect method of
+condensation." This much determined, the next step looked toward the
+confirmation of his conclusions and the remedy of the defects.
+
+To meet the first difficulty he made a cylinder of wood, soaked in oil
+and baked, a non-conducting and non-radiating material. Then he was
+able to determine with some accuracy the quantities of steam and
+injection water used in the engine; and a comparison with the original
+cylinder and its operation showed that not only four times the
+quantity of steam, but also four times the amount of injection water
+was used as was necessary, assuming wastes checked. Further scientific
+research on the part of Watt gave him measures of specific heats of
+the metals and of wood, the specific volumes of steam at various
+working pressures, the evaporative efficiency of boilers, the
+pressures and temperatures of steam in the boiler under specified
+conditions, the quantities of steam and of water required for the
+operation of his little condensing engine.
+
+Then came his enunciation of the grand principle of economy in the
+construction and operation of the steam engine: "Keep the cylinder as
+hot as the steam which enters it," as he expressed it. This was Watt's
+guiding principle, as it has been that of all his successors in the
+improvement of the economic performance of the steam engine and of all
+other heat engines. The great source of waste is the dispersion of
+heat, uselessly, which should be applied to the production of work by
+its transformation, thermodynamically, into the latter form of energy.
+The second form of waste is that of power thus produced in the
+unprofitable work of moving the parts of the engine itself; and the
+third is that of heat by transfer, without transformation, by
+conduction and radiation to surrounding bodies. In modern engines, the
+latter is but three or five per cent., in the best cases; the second
+waste constitutes perhaps ten per cent.; while the first of these
+losses amounts very usually to seventy per cent., of which last
+one-third or one-fourth is of the kind discovered by Watt, the rest
+being the thermodynamic waste incident to all known methods of
+operation of heat engines, and apparently unavoidable. In our very
+best and largest engines, the waste found by Watt to constitute three
+fourths of all heat supplied has been brought down to ten per cent., a
+fact which well exemplifies the advances made since his time of
+apprenticeship by himself and his successors of this nineteenth
+century. The steam engine of to-day, in its most successful operation,
+gives us twenty-five times as much power from a pound of coal as did
+the engine that the great inventor sought to improve: this is the
+magnificent fruit of that one discovery of James Watt, and of
+application of the simple principle which he so concisely and clearly
+stated.
+
+The method adopted by Watt to secure a remedy, so far as practicable,
+of this defect of the older machine was as simple and as perfect as
+was the principle which it embodied. He first removed from the
+cylinder the prime source of its wastes; providing a separate
+condenser, and thus avoiding the repeated chilling of its surfaces by
+the cold water used in condensing the steam at exhaust, and also
+permitting its strokes to be made with far greater frequency, thus
+giving less time for cooling by the influence of the remaining vapors
+after condensation. He next went still further, and provided the
+cylinder with a closed top, keeping out the air, and a "jacket" of hot
+boiler steam to _keep_ it as hot as the steam which entered it. These
+were the two great improvements which converted the first real steam
+engine into an economical form of heat engine and essentially finished
+the work so grandly begun by Newcomen and Calley. These changes gave
+us the modern steam engine; and these are Watt's first and greatest,
+but by no means only, contributions to the production of the modern
+world with all its comforts, its luxuries and its opportunities for
+material, intellectual and moral advancement of individual and of
+race. His work was to this extent complete in 1765.
+
+But Watt did not stop here. There still remained for him the no less
+important and the, in some senses, still more imposing, work of
+finding employment for the new servant of mankind and of setting it at
+its work of giving the human arm a thousand times greater strength, to
+the mind of man uncounted opportunities to promote the advancement of
+knowledge, of civilization, of every good of the race. His was still
+the task of adapting the new machine to all the purposes of modern
+industry. It had been hitherto confined to the task of raising water
+from the depths of the mine; it was now to be harnessed to the railway
+train; to be made to drive the machinery of the mill, to apply its
+marvelous power to the impulsion of the river boat and ocean steamer;
+to furnish energy, through endless systems of transfer and use, to
+every kind of work that man could devise and should invent. All this
+meant the giving of the machine forms as various as the purposes to
+which it was to be devoted. It had previously only raised and
+depressed a rod; it must now turn a shaft. It had then only operated a
+pump; it must now turn a mill, grind our grain, spin our threads,
+weave our cloths, drive our shops and factories, supply the powerful
+blast of the iron furnace. It must be made to move with the utmost
+conceivable regularity, and must, with all this, do its work in the
+development of the hidden energy of the fuel, with the greatest
+possible economy, through the expansion of its steam. All this was
+achieved by James Watt.
+
+The invention of the double-acting engine, in which the impulsion of
+the steam is felt both in driving the piston forward and in forcing it
+backward, both upward and downward, the application of its force
+through crank and fly wheel, the creation of an automatic system of
+governing its speed, and the discovery of the economy due to its
+complete expansion, were all improvements of the first magnitude, and
+of the greatest practical importance; and all these were in rapid
+succession brought into existence by the creative mind that had
+apparently been brought into the world for the express purpose of
+giving to the hand of man this mighty agent, to perfect the mightiest
+power that mind of man has yet conceived.
+
+But to do the rest required more than inventive genius and mechanical
+skill. It demanded capital and the stored energy of labor and genius
+in other fields, directed by the mind of a great "captain of
+industry." This came to Watt through Matthew Boulton, a manufacturer
+of Birmingham, whose father and ancestors had gradually and
+toilsomely, as always, accumulated the property needed for the
+prosecution of a great business. The combination of genius and capital
+is always an essential to success in such cases; and good fortune, a
+Providence, we may well say, brought together the genius and the
+capitalist to do their work, hand in hand, of providing the world with
+the steam engine. Hand in hand they worked, and all the world to-day,
+and the race throughout its future life, must testify gratitude for
+the inexpressible obligations under which these two men have placed
+them, doing the work of the world.
+
+Boulton & Watt, the capitalist with the inventor, gave the world the
+steam engine, finally, in such form and in such numbers that its
+permanent establishment as the servant of man was insured. The
+capitalist was as essential an element of success as was the inventor,
+and, in this instance, as in a thousand others, the race is indebted
+to that much-abused friend of the race, the capitalist, for much that
+it enjoys of all that it desires. The industry and patience, the skill
+and the wisdom required for the accumulation of this energy stored for
+future use in great enterprises is as important, as essential, as
+inventive power or any other form of genius. Talent and genius must
+always aid each other. This firm was established in 1764 and its main
+resources, aside from the bank account, were Watt's patent, about
+expiring, and Watt's genius, and Boulton's talent as a man of
+business. The patent was extended for twenty-four years, the new
+inventions of Watt, now beginning to pour from his prolific brain in a
+wonderful stream, were also patented, and the whole works were soon
+employed upon the construction of engines for which numerous orders
+soon began to pour in upon the now prosperous builders. The patent law
+established Boulton and Watt and the firm paid back the nation with
+handsome usury, giving it unimaginable profits indirectly through its
+control of the work of the world and large profits directly through
+the business brought them from all parts of the then civilized globe.
+There has never, in the history of the world, been a more impressive
+illustration of the value to a nation of that generous public policy,
+that simply just legislation, which gives to the man of brain control
+of the products of his mind. For a hundred years, Great Britain has,
+largely through her encouragement of the inventor and her protection
+of his mental property by securing the fruits of his labors, in fair
+portion, to him, gained the power of dictating to the world and has
+gained an advance that cannot be measured. Watt and Arkwright and
+Stephenson and Crompton and their ilk, protected by their government
+and its patent laws, made their country the peaceful conqueror of the
+world. The story of the work of the inventor is a poem of mighty
+meaning and of wonderful deeds. The inventor proved himself a mightier
+magician than ever the world had seen.
+
+    "A creature he called to wait on his will,
+    Half iron, half vapor--a dread to behold;
+    Which evermore panted, and evermore rolled,
+    And uttered his words a millionfold."
+
+Such was the outcome of this grand modern "trust," a combination of
+the wisest legislation, the most brilliant invention, and the most
+wisely applied capital. There are "trusts" of which the outcome is
+most beneficent.
+
+Since the days of Watt, the improvement of the steam engine and the
+work of inventors has been confined to matters of detail. All the
+fundamental principles were developed by Watt and his predecessors and
+contemporaries and it only was left to his successors to find the best
+ways of carrying them into effect. But these matters of detail have
+been found to involve opportunities to make enormous strides in the
+direction of securing improved efficiency of the machine. The further
+application of the principle which led Watt to his greatest
+inventions; of the principle, keep the cylinder as hot as the steam
+which enters it, of that which he enunciated relative to the advantage
+of expanding steam, and of that affecting the regulation of the
+machine; have reduced the costs of steam and of fuel to a small
+fraction of their earlier magnitude. One ton of engine to-day does the
+work of eight or ten in the time of Watt: one pound of fuel or of
+steam gives to-day ten times the power then obtained from it. A
+steamship now crosses the Atlantic in one-eighth the time required by
+the famous "liner" of the "Black Ball Line." The wastes of the engine
+have been brought down from above eighty per cent. to eight; and a
+half-ounce of fuel on board ship will now transport a ton of cargo
+over a mile of ocean.
+
+FREDERICK E. SICKELS gave us the first practicable form of expansion
+gear in 1841; GEORGE H. CORLISS gave a new type of engine of marvelous
+perfection and economy in 1849; Noble T. Green, Wm. Wright and many
+less well known but no less meritorious inventors have since done
+their part in the transformation of the old engine of Watt into the
+modern wonder of concentrated and economical power, and marvel of
+accurate and beautiful design and workmanship. The "trip cut-off,"
+with reduced clearances, increased boiler pressure, higher rates of
+expansion, accelerated speeds of engine, better construction in all
+respects, as well as improved design, have enabled us to avail
+ourselves to the utmost of the principles of Watt, and our mills, our
+railways, our steamers and our fields, even, have gained almost as
+extraordinarily by these advances, since the days of the great
+inventor, as through his immediate labors.
+
+With the introduction of the new form of older energy, electricity,
+with the reduction of the lightning into thraldom, has now come a new
+impulse affecting all the industries. Through its mysterious, its
+still unknown action, steam now reaches out far from its own place,
+driving the electric car along miles of rail; giving light throughout
+all the country about it, turning night into day, and repressing crime
+while encouraging legitimate labor, reaching into distant chambers and
+every little workshop, to offer its powerful aid in all the
+distributed work of cities. Without the steam engine there would be
+little work available for electricity, but the appearance of this, the
+latest and most useful handmaid of steam, has given the engine work to
+do in an uncounted number of new fields, has called in the inventor
+once more to adapt steam to its new work. The "high-speed engine" is
+the latest form of the universal helper. And such has been the
+readiness and the intelligence of the contemporary inventor that we
+now have engines capable of turning their shafts three hundred
+rotations a minute and without a perceptible variation of velocity,
+whatever the change of load or the suddenness with which it is varied.
+In the days of Watt a fluctuation of five per cent. in speed was
+thought wonderfully small; in those of Corliss, the variation was
+restricted to two per cent. and we wondered at this unanticipated
+success. To-day, thanks to Porter and Allen, to Hartnell, to Hoadley,
+to Sims, to Thomson, to Sweet, to Ide, and to Ball, we have seen the
+speed fluctuation restricted to even less than one per cent. of its
+normal average.
+
+The inventors of the steam engine are, through their representatives
+of to-day, according to the statisticians, doing the equivalent of
+twelve times the work of a horse, for every man, woman and child on
+the globe. We have not less, probably, than a half million of miles of
+railway, transporting something over 150,000,000,000 of tons a mile a
+year. A horse is reckoned to haul a ton weight about six and a half
+miles, day by day, by the year together. In the United States, it is
+reckoned that the steam engine, on the railways alone, hauls a
+thousand tons one mile, for every inhabitant of the country, every
+year, or, if it is preferred to so state it, a ton a thousand miles.
+This is the way in which the East and the West are, by the inventors
+of the steam engine, enabled to help each other. This costs about $10
+each individual; it would require some 25 millions of horses to do the
+work, and would cost about $1,000 a family, which is more than twice
+the average family earnings.
+
+Dr. Strong, in that remarkable book, "Our Country," says: "One man, by
+the aid of steam, is able to do the work which required two hundred
+and fifty men at the beginning of the century. The machinery of
+Massachusetts alone represents the labor of more than 100,000,000 men,
+as if one-half of all the workmen of the globe had engaged in her
+service." And again: "Some thirty years ago, the power of machinery in
+the mills of Great Britain was estimated to be equal to 600,000,000
+men, or more than all the adults, male and female, of all mankind."
+Mr. Gladstone estimated that the aggregation of wealth on the globe
+during the whole period from the birth of Christ to that of Watt was
+equaled by the production in twenty years, at the middle of this
+century, with the aid of machinery driven by the fruit of the brain of
+the inventors of the steam engine. We may probably now safely estimate
+the former quantity as rivaled in less than five years, while, since
+the birth of Watt and his engine, and the production of the spinning
+mule, the power loom, the cotton gin and our own patent system and its
+marvelous mechanism, all events of a century ago, we may estimate that
+they have, together, accomplished more in this period which we now
+celebrate than could have been done in a millenium of milleniums
+without these now subjected genii. But the power behind all these
+curious inventions and their work is that of steam. The steam engine
+even supplies power to the telegraph and transports words and thought
+as well as cotton bales and coal.
+
+And now what has this combination of legislation for private
+protection and public good, of a genius producing great inventions,
+and of the accumulated capital of earlier years, brought about?
+
+It has given us the best fruits of science in permanent possession.
+The study of science invariably aids, in a thousand ways, the progress
+of mankind. It gives us new conceptions of nature and of the
+possibilities of art; it promotes right ways of work and of study; it
+teaches the inventor and the discoverer how most surely and promptly
+to gain their several ends, it gives the world the results of all
+acquired knowledge in concrete form. This one instance which we are
+now especially interested in contemplating has performed more
+wonderful miracles than ever Aladdin's genii attempted. One man, with
+a steam engine at his hand, turns the wheels of a great mill, drives
+forty thousand spindles, applies a thousand horse power to daily work
+in the spinning of threads, the weaving of cloth, the impulsion of a
+steamboat, or the drawing of great masses of hot iron into finest
+wire. This puny creature, his mind in his finger tips, exerts the
+power of ten thousand men, working with muscle alone, and, aided by a
+handful of women, boys and girls, clothes a city. A half dozen men in
+the engine room of an ocean steamer, with a hundred strong laborers in
+the boiler room and on deck, transports colonies and makes new
+nations, brings separated peoples together, unites countries on
+opposite sides of the globe, brings about easy exchanges between pole
+and equator. One man on the footboard of the locomotive, one man
+shoveling into the furnaces the black powder that incloses the energy
+stored in early geological ages, a half dozen men mounted on the long
+train of following vehicles, combine to bring to the mill girl in
+Massachusetts, the miner in Pennsylvania, the sewing woman, and the
+wealthy merchant, her neighbor in New York, the flour made in
+Minnesota from the grain harvested a few weeks earlier in Dakota. All
+the world is served faithfully and efficiently by this unimaginable
+power, this product of the brain of the inventor, protected by the
+law, stimulated and aided by the capital that it has itself almost
+alone produced.
+
+And thus have the inventors of the steam engine set in motion and
+placed at the disposal of mankind for every form of useful work all
+the great forces of nature; thus Hero of Alexandria touched the then
+concealed spring which called all the genii of earth, fire, water and
+air to do the bidding of the race. Thus Papin, Worcester, Newcomen,
+Watt, and Corliss and others of our own contemporaries, have applied
+the genii to their task of leveling mountains, traversing seas,
+continents, and the depths of the earth, building ships, locomotives,
+hamlets and cities, cottages and palaces, turning the spindle,
+operating the loom, and setting motion and giving energy to every
+machine, doing the work of thousands of millions of men, converting
+barbarism into civilization, giving necessaries of life in profusion,
+comforts in plenty, and luxuries in superabundance.
+
+Aiding and working hand in hand with those other genii of progress,
+the inventors of the printing press and of the telegraph, the
+telephone, and the electric railway, of the modern system of textile
+manufactures, of iron and steel making, of the mowing machine and the
+harvester, they have compressed into two centuries the progress of a
+millennium, destitute of their aid. Every step taken under their
+stimulus, and with their help, is a step toward a higher life for all,
+intellectually and morally as well as physically; every advance in the
+improvement of their work is a gain to every man, woman, and child;
+every improvement of the steam engine is a help to the whole world.
+This progress makes the day of the extinction of the system now
+grinding the populations of the earth into the ground, the day of the
+abolition of armies and the restoration to the people of that freedom
+which characterized the times of the patriarchs, and of the
+restoration of the rights of the citizen to his own time and strength
+and producing power, perceptibly nearer.
+
+When this final revolution shall have been accomplished, and when all
+the world has settled down to the steady and undisturbed work of
+production by daily and regular labor, aided by the genii of steam, of
+electricity, of all nature, combined for good, the results of the
+intellectual activity of the inventors of the steam engine will be
+fully seen. Then no monument will be required to keep green the memory
+of Watt, Corliss, or any other of these great men, but it will be said
+of them, as of Sir Christopher Wren in the epitaph in St. Paul's:
+"Seek you a monument, look about you!" Every wreath of steam rising to
+the heavens from factory, mill or workshop will be a reminder of Hero
+of Alexandria, every mine will possess a memorial to Papin, Worcester
+and Savery; every steamship will bring into grateful memory Fitch and
+Stevens, and Bell and Fulton; thousands of locomotives, crossing the
+continents, will perpetuate the thought of the Stephensons and their
+colleagues in the introduction of the railway; the hum of millions of
+spindles and the music of the electric wire will tell of the work of
+Corliss and his contemporaries and successors who made these things
+possible, and all kingdoms and races, all nations, will revere the
+name of James Watt, the genius to whom the world is most indebted for
+the beginnings of all this later and grander civilization which has
+converted the slow progress of earlier centuries into the meteor-like
+advance of to-day toward a future as grand and as mighty and as noble
+as humanity shall choose to make it.
+
+       *       *       *       *       *
+
+
+
+
+IMPROVED HAND CAR.
+
+
+[Illustration]
+
+In the accompanying illustration we show a new design of hand car,
+being introduced by the Courtright Manufacturing Co., of Detroit. It
+will be seen that the apparatus for propelling the car is very
+different from the mechanism generally used. An upright framework
+secured to the platform carries a large sprocket wheel, which is
+connected to a smaller one upon one of the axles by means of a chain.
+The larger sprocket wheel is rotated by means of a triangular shaped
+lever attached at the lower corner to the crank of the sprocket wheel
+and having a handle at each of its upper corners. It is hinged upon a
+fulcrum which slides upon the two vertical rods shown in the
+illustration. It will be seen that this gives a peculiar movement to
+the handles by which the operators propel the car, but it has been
+found that the motion is an excellent one, and it is claimed that a
+higher speed can be obtained with the mechanism here shown than with
+any other now in use. There is practically no dead center, as in the
+case where the ordinary crank and lever is used. A number of leading
+roads have given the car a trial, and being well satisfied it, have
+given orders for more. The company claim that a car with 20 in. wheels
+can easily be made to attain a speed of 15 miles an hour by two
+men.--_Railway Review_.
+
+       *       *       *       *       *
+
+
+
+
+THE CONIC SECTIONS.
+
+By Prof. C.W. MACCORD, Sc.D.
+
+
+In Fig. 1 let D be a given point, and O the center of a given circle,
+whose diameter is FG. Bisect DF at A. Also about D describe an arc
+with any radius DP greater than DA, and about O another arc with a
+radius OP = DP + FO, intersecting the first arc at P, then draw PD,
+and also PO, cutting the circumference of the given circle in L. Since
+PD = PL, and DA = AF, it is evident that by repeating this process we
+shall construct a curve PAR, which satisfies the condition that _every
+point in it is equally distant from a given point and from the
+circumference of a given circle_. Since PO-PD = LO, and AO-AD = FO,
+this curve is one branch of the hyperbola of which D and O are the
+foci.
+
+[Illustration: FIG. 1]
+
+Bisect DG at B, then about D describe an arc with any radius DQ
+greater than DB, and about O another are with radius OQ = DQ-FO; draw
+from Q the intersections of these arcs, the line QD, and also QO,
+producing the latter to cut the circumference in E. By this process we
+may construct the curve QBZ, each point of which is also equally
+distant from the given point D, and from the concave instead of the
+convex arc of the given circumference. The difference between QD and
+QO being constant and equal to FO, and AB being also equal to FO, this
+curve is the other branch of the same hyperbola, whose major axis is
+equal to the radius of the given circle.
+
+The tangent at P bisects the angle DPL, and is perpendicular to DL,
+which it bisects at a point I on the circumference of the circle whose
+diameter is AB, the major axis, the center being C, the middle point
+of D O. As P recedes from A, it is evident that the angles P D L, P L
+D, will increase, until D L assumes the position D T tangent to the
+given circle, when they will become right angles. P will therefore be
+infinitely remote, and the point I having then reached t, where D T
+touches the smaller circle, C t S will be an asymptote to the curve.
+This shows that the measurements from the convex arc, for the
+construction of A P, are made only from the portion F T of the given
+circumference.
+
+In the diagram the point Q is so chosen that D L produced passes
+through E, so that Q J, the tangent at Q, is parallel to P I. It will
+thus be seen that the measurements from the concave arc, for the
+construction of B Q, are confined to the portion G T of the given
+circumference. As D L E rises, the points P and Q recede from A and B,
+the points L and E approach each other, finally coinciding at T; at
+this instant I and J fall together at t, so that S S is the common
+asymptote to A P and B Q.
+
+In Fig. 2 the given point D lies within the circumference of the given
+circle. Bisect D F at A, and D G at B; about D describe an arc with
+any radius D P greater than D A, and about O another, with radius O P
+= O F--D P, these arcs intersect in P, and producing O P to cut the
+circumference in L, we have P D = P L. Similarly E D = E H, U D = U W,
+etc. And since P D + P O = L P + P O, D E + E O = H E + E O, and so
+on, the curve is obviously the ellipse of which the foci are D and O,
+and the major axis is A B = F O, the radius of the given circle.
+
+[Illustration: FIG 2.]
+
+If, as in Fig. 3, the given point be made to coincide with the center
+of the circle, the ellipse becomes a circle with diameter A B = F O.
+But if the point be placed upon the circumference, as in Fig. 4, the
+ellipse will reduce to the right line A B coinciding with F O.
+
+[Illustration: FIGS 3, 4, 5, 6.]
+
+In this case we may also apply the same process as in Fig. 1; D T
+becomes a tangent at D to the circumference, and the asymptotes
+coincide with the axis of the hyperbola, of which one branch reduces
+to the right line A P extending from A to infinity on the left, and
+the other reduces to the right line B G Q, extending from B to
+infinity on the right.
+
+If the circle be reduced to a point, as in Fig. 5, the resulting locus
+is a right line perpendicular to and bisecting D O. If on the other
+hand the diameter of the given circle be infinite, the circumference,
+as in Fig. 6, becomes a right line perpendicular to the axis at F, and
+the curve satisfies the familiar definition of the parabola, D E being
+equal to E H, D P equal to P L, and so on.
+
+In Fig. 7, as in Fig. 1, DT is tangent at T to the given circle whose
+center is O, and at t to the circle about C whose diameter is AB, the
+major axis. Since DTO is a right angle, T lies upon the circumference
+of the circle whose center is C, and diameter DO; this circle cuts the
+asymptote SCS at M and N. The semi-conjugate axis is a mean
+proportional between D A and AO; now drawing TM and TN, it is seen
+that Tt is that mean proportional; and a circle described about C with
+that radius will be tangent to TO. DT, then, is the radius of the
+circle to be described about the focus of the conjugate hyperbola for
+its construction according to the enunciation first given: and we
+observe that DT and TO are supplementary chords in the circle about C
+through D and O. The conjugate foci must therefore lie upon this
+circumference, at D' and O'; and since D'O' is perpendicular to DO,
+D'T will be perpendicular and T'O' will be parallel to SCS.
+
+[Illustration: FIG 7.]
+
+Now as TO increases, T'O' will diminish, until, when TO equals DO,
+T'O' will vanish and with it Ct'; and at this crisis, the case is the
+same as in Fig. 4; but the conjugate hyperbola logically reduces to
+_two_ right lines, extending from C to infinity on the right and left.
+As indeed it should from the familiar construction, since the
+distances from D' and O' to any point on the horizontal axis being
+equal, their difference is constant and equal to zero.
+
+It appears, then, that a conic section may be defined as the locus of
+a point which is equally distant from a given point and from the
+circumference of a given circle. Boscovich defines it as the locus of
+a point so moving that its distances from a given point and from a
+given right line shall have a constant ratio.
+
+The latter definition involves the conceptions of a rectilinear
+directrix, and a varying ratio in the cases of the different curves,
+this ratio being unity for the parabola, less for the ellipse, and
+greater for the hyperbola. The former involves the conception of a
+circular directrix with a ratio equal to unity in all cases; and the
+two definitions become identical in the construction of the parabola,
+which is in fact the only curve of which a clear idea is given by
+either of them. That of Boscovich has been given a prominence far in
+excess of its merits, being made the foundation for the discussion of
+these important curves, and this in a textbook whose preface contains
+the following true and emphatic statement, viz.:
+
+    "The abstract nature of a ratio, and the fact that it is a
+    compound concept, peculiarly unfit it for elementary
+    purposes."
+
+The definition herein set forth has not been given in any treatise on
+the subject, so far as we have been able to ascertain. And it is
+presented with the distinctly expressed hope that it never will be,
+except as a mere matter of abstract interest.
+
+Of this it may, like the other, possess a little, but both have the
+great disadvantage that, except in relation to the parabola, the idea
+which they convey to the mind of the curves to which they relate, if
+indeed they convey any at all, is most obscure and indirect; and of
+practical utility neither one can claim a particle.
+
+       *       *       *       *       *
+
+
+
+
+TABLE OF ATOMIC WEIGHTS.
+
+(Issued December 6, 1890.)
+
+
+By request of the Committee of Revision and Publication of the
+Pharmacopoeia of the United States of America, Prof. F.W. Clarke,
+chief chemist of the United States Geological Survey, has furnished a
+table of atomic weights, revised upon the basis of the most recent
+data and his latest computations. The committee has resolved that this
+table be printed and furnished for publication to the professional
+press. The committee also requests that all calculations and
+analytical data which are to be given in reports or contributions
+intended for its use or cognizance be based upon the values in the
+table. It would be highly desirable that this table be adopted and
+uniformly followed by chemists in general, at least for practical
+purposes, until it is superseded by a revised edition. It would only
+be necessary for any author of a paper, etc., to state that his
+analytical figures are based upon "Prof. Clarke's table of atomic
+weights of December 6, 1890," or some subsequent issue.
+
+This table represents the latest and most trustworthy results, reduced
+to a uniform basis of comparison, with oxygen=16 as starting point of
+the system. No decimal places representing large uncertainties are
+used. When values vary, with equal probability on both sides, so far
+as our present knowledge goes, as in the case of cadmium (111.8 and
+112.2), the mean value is given in the table.
+
+The names of elements occurring in pharmaceutical, medicinal,
+chemicals, are printed in italics[1]:
+
+[Transcriber's Note 1: ITALICS represented by surrounding with "_".]
+
+
+  Name.           Symbol.  Atomic Weight.
+
+_Aluminum_.        _Al_        27.
+_Antimony_.        _Sb_       120.
+_Arsenic_.         _As_        75.
+_Barium_.          _Ba_       137.
+_Bismuth_.         _Bi_       208.9
+_Boron_.           _B_         11.
+_Bromine_.         _Br_        79.95
+Cadmium.            Cd        112.
+Caesium.            Cs        132.9
+_Calcium_.         _Ca_        40.
+_Carbon_.          _C_         12.
+_Cerium_.          _Ce_       140.2
+_Chlorine_.        _Cl_        35.45
+_Chromium_.       _Cr_         52.1
+Cobalt.             Co         59.
+Columbium.[1]       Cb         94.
+_Copper_.          _Cu_        63.4
+Didymium.[2]        Di        142.3
+Erbium.             Er        166.3
+Fluorine.           F          19.
+Gallium.            Ga         69.
+Germanium.          Ge         72.3
+Glucinum.[3]        Gl          9.
+_Gold_.            _Au_       197.3
+_Hydrogen_.        _H_          1.007
+Indium.             In        113.7
+_Iodine_.          _I_        126.85
+Iridium.            Ir        193.1
+_Iron_.            _Fe_        56.
+Lanthanum.          La        138.2
+_Lead_.            _Pb_       206.95
+_Lithium_.         _Li_         7.02
+_Magnesium_.       _Mg_        24.3
+_Manganese_.       _Mn_        55.
+_Mercury_.         _Hg_       200.
+_Molybdenum_.      _Mo_        96.
+Nickel.             Ni         58.7
+_Nitrogen_.        _N_         14.03
+Osmium.             Os        191.7
+_Oxygen_.[4]       _O_         16.
+Palladium.          Pd        106.6
+_Phosphorus_.      _P_         31.
+Platinum.           Pt        195.
+_Potassium_.       _K_         39.11
+Rhodium.            Rh        103.5
+Rubidium.           Rb         85.5
+Ruthenium.          Ru        101.6
+Samarium.           Sm        150.
+Scandium.           Sc         44.
+Selenium.           Se         79.
+_Silicon_.         _Si_        28.4
+_Silver_.          _Ag_       107.92
+_Sodium_.          _Na_        23.05
+Strontium.          Sr         87.6
+_Sulphur_.         _S_         32.06
+Tantalum.           Ta        182.6
+Tellurium.          Te        125.
+Terbium.            Tb        159.5
+Thallium.           Tl        204.18
+Thorium.            Th        232.6
+Tin.                Sn        119.
+Titanium.           Ti         48.
+Tungsten.           W         184.
+Uranium.            U         239.6
+Vanadium.           V          51.4
+Yterbium.           Yb        173.
+Yttrium.            Yt         89.1
+_Zinc_.            _Zn_        65.3
+Zirconium.          Zr         90.6
+
+--_Am. Jour. Pharm._
+
+[Footnote 1: Has priority over niobium.]
+
+[Footnote 2: Now split into neo-and praseo-didymium.]
+
+[Footnote 3: Has priority over beryllium.]
+
+[Footnote 4: Standard, or basis of the system.]
+
+       *       *       *       *       *
+
+
+
+
+THE TANNING MATERIALS OF EUROPE.
+
+
+The tanning materials of Europe are of an altogether different type
+from those of the United States. The population is so dense that the
+quantity of home materials produced is not nearly proportionate to the
+amount consumed, and consequently they must draw upon surrounding
+lands for their supply. The vegetation of these adjacent countries is
+of a much more tropical nature, and it naturally follows that the
+tanning materials are also of a different species.
+
+Tanning materials may be divided into two great classes, viz.:
+Physiological and pathological.
+
+
+PHYSIOLOGICAL.
+
+The first class includes those tannins which are the results of
+perfectly natural or normal growth, and a growth necessary to the
+development of vegetation, for instance, bark, sumac, etc., whereas
+the second class contains those which are the results of abnormal
+growth, caused by diseases, stings of insects, etc. An example of this
+is the gall. Both of these classes are used to a great extent in
+Europe, while only the first division is in general use in the United
+States. We will first consider the physiological tannins.
+
+
+_Oak Bark._--This material was, is, and will be for some time to come
+the main tanning material in use here in Europe. The advantages of the
+oak tannage are as fully appreciated here as in the United States. The
+European oak gives a light colored, firm leather, with good weight
+results, is comparatively cheap and of an excellent quality. The
+varieties are numerous, each country having its own kind. Those in
+most general use are:
+
+_Spiegel Rinde_ (mirror bark).--This bark is well distributed
+throughout Europe, and is peeled when the tree has attained a growth
+of from 12 to 24 years. It is marketed in three grades.
+
+_Reitel Rinde_--Is obtained from the same tree as the spiegel rinde,
+but after the tree has attained a growth of from 25 to 40 years.
+
+_Alte Pische_ (old oak).--Obtained from the aged tree. It is not as
+valuable as the younger bark, and consequently brings a much lower
+price.
+
+Spiegel rinde may be judged by small warts which appear on the shining
+surface of the bark. The presence of a great number of these, as a
+rule, indicates a high tannin percentage.
+
+Bosnia has fine oak trees, the bark containing 10 to 11 per cent.
+tannin.
+
+Bohemia has the _trauben eiche_ (grape oak).
+
+France uses the kirmess oak, which grows in the south of that country
+and in northern Africa. Two grades are made, viz., root and trunk.
+
+Tyrol has the evergreen oak--12 to 13 per cent. tannin.
+
+Sardinia possesses a cork oak, which yields 13 to 14 per cent.
+
+White oak is found throughout Europe, yielding 10 per cent. The price
+of oak bark varies a great deal. The assortment is much more strict
+than in the United States. In Austria it brings 4 to 5 fl., equal to
+$1.60 to $2 per kilo. (224 lb.); in Germany, 11 to 16 marks per 100
+kilos.[1]
+
+[Footnote 1: In the principal districts in America, removed from the
+cities, the price of oak bark is about $4 to $6 per cord or per ton
+of 2,240 lb. The hemlock bark, which gives a sole leather just as
+thoroughly tanned, but of a darker and reddish color, costs the
+larger tanners from $3 to $4 a cord.]
+
+The above mentioned varieties are all used for both upper and sole
+leather. In Germany a great deal of upper leather is pure oak tannage,
+but one seldom finds a pure oak tanned sole leather; it is almost
+always in combination with other tannics.
+
+
+_Pine Bark_--Is well distributed and is a very important tanning
+material. It bears the same relation to oak bark here as does hemlock
+in America, but its effects are quite different from hemlock. The best
+Austrian sorts are those of Styria and Bohemia, but that of Karuthen
+is also of good quality. The German pine comes from Thuringia to a
+great extent. The countries that consume the greatest amount of pine
+bark are Austria, Germany, Russia and Italy. The tannin contained
+varies from 5 to 16 per cent. Its use is almost wholly confined to the
+handlers, as its weight returns are not so satisfactory as oak or
+valonia. In case it should be used for layers it is always in
+combination with some better weight-giving tannic. For upper leather
+its use is limited.
+
+The bark is always peeled from the felled tree, and often the woodman
+accepts the bark in part payment for his labor; he then sells the bark
+to the tanner or agents who go about the country collecting bark. It
+is generally very nicely cleaned. I would here like to correct a
+mistake which tanners often make in their estimations of the value of
+barks. A tanner usually buys the bark of southern-grown trees in
+preference to that of trees grown in northern countries, as it is a
+common idea that southern vegetation contains more tannin than that of
+the north. This is a fallacy, as has not only been proved by careful
+analyses, but may also be found to be an incorrect conclusion after a
+moments' thought. Those trees which flourish in southern countries
+grow very rapidly, and as tannin is necessary to the development of
+leaf structure, etc., it is absorbed to a greater extent than is the
+case with the slower-growing tree of the north. The tannin contained
+in the sap does not increase in the same ratio as does the rapid
+growth, and it follows that the remainder in the bark is less than in
+the tree of slower growth.
+
+
+_Birch Bark_--Is at home in Russia, Norway, and Sweden. It is used for
+both upper and sole leather, but seldom alone. The bark is usually
+peeled from the full grown tree, and contains 4 to 9 per cent. tannin.
+
+
+_Willow Bark_--May also be found in the above mentioned countries and
+also in Germany. This material is used for both upper and sole
+leather, and contains 6 to 9 per cent. tannin. It is a very delicate
+material to use, as its tannin decomposes rapidly.
+
+
+_Erlen Rinde_--Is also a native of Germany, but is not used to any
+great extent. The same may be said of the larch, although this variety
+is also to be met with in Russia.
+
+
+_Mimosa Bark_--Is obtained from the acacia of Australia. It is a
+favorite in England. The varieties are as follows: Gold wattle, silver
+wattle (blackwood, lightwood), black wattle, green wattle. The gold
+wattle is a native of Victoria. Its cultivation was tried as an
+experiment in Algeria and met with some success. The trees are always
+grown from seeds. These seeds are laid in warm water for a few hours
+before sowing. The acacia may be peeled at eight years' growth and
+carries seeds. The Tasmania bark is very good; that from Adelaide
+likewise good.
+
+Sydney does not produce so good an article, but Queensland better. The
+bark is marketed in the stick, ground or chopped.
+
+Madagascar and the Reunion Islands have also a mimosa bark.
+
+The mimosa barks give a reddish colored leather, pump well and contain
+a high tannin percentage, 10 to 35 per cent.
+
+
+Now we will consider the fruit tanning materials.
+
+Valonia may truly be called one of the most generally used tanning
+agents at present employed in Europe. All countries consume it more or
+less. Valonia was first used in England about the beginning of this
+century. A few years later Germany began using it, and still later
+Austria introduced it. It is the fruit of the oak tree and is
+obtainable in Asia Minor and the adjacent islands. In form it
+resembles the American acorn, but in size it nearly trebles it. The
+fruit may be divided into two parts, namely, the cup and acorn, and
+the cup again divided into trillor and inner cup. The acorn only
+contains 10 per cent. tannin, whereas the cup contains from 25 to 40
+per cent.
+
+The percentage depends altogether upon the time of harvesting and the
+place of growth. The best valonia is derived from Smyrna, and is
+naturally the highest priced article. Valonia is worth from 22 to 28
+florins ($9 to $11) per 100 kilos. (224 pounds) at present. The other
+provinces and islands from which it is obtainable are Demergick,
+Govalia, Idem, Ivalzick, Troy (this is the best); Metelino Island, the
+vicinity of Smyrna. The material sold in three grades--prime, mazzano;
+seconds, una aqua; thirds, skart.
+
+The product of Smyrna generally averages:
+
+                       Tons.           Price.
+    Prime.        2,000 to  3,000      28 florins.
+    Seconds.      5,000 to 10,000      25    "
+    Thirds.      20,000 to 30,000      22    "
+
+The _Metilino_ valonia is a product of a neighboring island, and is a
+very good article. It may be easily distinguished by its thin cup. It
+is harvested in September.
+
+The _Candia_ valonia is nearly as long as it is wide, in contrast to
+the Smyrna, which is much wider than long. The recent harvest showed a
+return of 800 to 1,000 tons, but no assortment is made. A grade called
+the Erstlige is sold, this being the first which has fallen to the
+ground before maturing.
+
+A peculiarity of the valonia is that it often strikes out a sort of
+sugar sweat, which gives the cup a less attractive appearance, but
+denotes the presence of large quantities of tannin.
+
+Valonia is used almost wholly for sole leather, either alone or in
+combination with pine or oak bark or knoppern and myrabolams. The
+union of valonia and knoppern is that in most general use. Valonia
+gives the leather a yellowish appearance, as it deposits a great deal
+of yellow bloom. The leather is very firm and of good wearing
+qualities. The weight results are also excellent, as will be seen
+below. To sole leather there are usually given from one to three
+layers of valonia. The demand for valonia is increasing more and more
+every year, and the present outlook does not indicate any relaxation
+of its popularity. Its use for upper leather is very limited.
+
+Myrabolams are mainly used in England and Austria, and give a nice
+light-colored leather, both upper and sole, although rarely used
+alone. Their main use is for dyeing purposes. They are indigenous to
+the East Indies.
+
+Sumac is so well known that treating of it is superfluous. Its use is
+very extensive, and it is a general favorite for light, fine leather,
+which is mostly used for colors.
+
+_Gambier_--Is in general use in England and to some extent in Germany.
+
+_Catechu_.--Obtained from India, resembles gambier greatly. Its use is
+almost wholly confined to England. It is also consumed by the silk
+manufacturers in preference to gambier, for weighting purposes.
+
+
+PATHOLOGICAL.
+
+We now leave the physiological class and take up those tanning
+materials included in the pathological class, or those of abnormal
+growth.
+
+
+_Galls_.--These are not consumed to any great extent at the present
+period, but formerly they were used quite extensively. The galls are
+found upon the leaves of the oak or sumac, etc. The direct cause of
+their growth is that a certain wasp (cynips galles) stings into the
+leaf and after depositing its egg, flies away. The egg develops into a
+larva and then into a full-fledged wasp, boring its way out of the
+gall which has served as a protection and nourisher. This accounts for
+the hole noticed in almost every gall. The different varieties include
+Aleppo. It is found upon the same trees as the valonia and contains 60
+to 75 per cent. tannin; Istrian galls, 32 per cent. tannin; Persian,
+28 to 29 per cent. tannin. Chinese galls, giving 80 to 82 per cent.
+tannin, are the results of the sting of a louse, and make a very
+light-colored leather. The dyers also use this material for coloring.
+
+
+_Knoppern_--Belongs to the family of galls, and is a most important
+factor of commerce in Austria. The knopper is generally found on the
+acorn or leaf of the oak tree. The greatest quantity is derived from
+the steel oak of Hungary. The tannin contained varies from 27 to 33
+per cent. Knoppern are not being used so much now as formerly, and
+consequently the amount harvested lessens from year to year. Its main
+use was and is in combination with valonia as layers for sole leather.
+Valonia gives better weight results than knoppern, and is replacing
+knoppern more and more every year. The combination of knoppern,
+valonia and myrabolams is also quite popular, and gives good results.
+Knoppern are seldom used alone, being generally combined with some
+other tannin. Austria is almost the only consumer at present, but
+Germany used it extensively formerly.
+
+
+_Bark and Wood Extracts_--Are becoming general favorites throughout
+Europe, partly because of their weight-giving qualities and partly as
+the transportation costs so little; they can be used to strengthen
+weak bark liquors.
+
+_Oak Extracts_--Are well liked, both wood and bark, and are used
+extensively. Slavonia furnishes a great deal of it.
+
+_Chestnut Oak Wood Extract_--Is manufactured in quantities, and easily
+finds purchasers.
+
+_Pine Bark Extract_--Is also consumed in goodly amounts.
+
+_Quebracho Wood Extract_.--The wood is shipped from Brazil to Hamburg
+and other ports, and the tannin extracted there. Hamburg furnishes
+quantities of it.
+
+_Hemlock Extract_--Is used in Russia, and seems to have taken a hold
+on the shoe buyers' fancies, as they now make imitations of it in
+color. The hemlock that is consumed is imported from America.
+
+
+As most leather is sold by weight in Europe, the leather manufacturers
+aim to obtain as good weight results as possible, and often, I am
+sorry to say, do so at the sacrifice of quality. This is common to
+both upper and sole leather. Sole leather is nine times out of ten
+given false weight by forcing entirely foreign substances into the
+leather, such as glucose, barium chloride, magnesium chloride, resins,
+etc. Glucose and resin are also used for weighting upper leather.
+Leather is also weighted with extracts by overtanning. Leather buyers
+have become very wary of late and do not purchase large quantities
+before an analysis is made of a fair sample.
+
+One more word before I close. The governments and private individuals
+in Europe cultivate and raise trees for both lumber and bark purposes.
+The forests are excellently cared for by efficient foresters, and the
+result is that the tanners obtain much cleaner and better bark, and of
+a very even quality. Would it not be a good idea if some individual,
+who would certainly earn the everlasting gratefulness of the tanners,
+would look into this matter, and see that not only the lumber side of
+our forest cultivation is not neglected, but that the bark also is
+preserved and cared for? Of course, we can obtain all the bark
+necessary at present and for some time to come, but the time will come
+when we shall certainly regret not having taken these steps, if the
+lumbermen and bark peelers go on devastating magnificent forests.
+Below will be found a table of weight results. Sole leather tanned
+with these materials gives for every 100 lb. green hide the following
+quantities of finished leather:
+
+                                     lb.
+  Oak bark                          48 to 54
+  "   extract                       55 to 56
+  Pine bark                         44 to 46
+  "   extract                       48 to 50
+  Willow                            45 to 46
+  Birch bark and oak extract        49 to 51
+  Quebracho wood and extract        48 to 49
+  Valonia                           52 to 56
+  Knoppern                          51 to 53
+  Myrabolams                        50
+  Knoppern, myrabolams and valonia  52 to 53
+  Hemlock                           55
+
+Specification of tanning materials used in different countries:
+
+_France_.
+Oak bark (kirmess).
+Sumac.
+Chestnut wood extract.
+Quebracho "     "
+Some gambier.
+
+_Italy_.
+Oak bark.
+Pine "
+Sumac.
+Valonia.
+
+_England_.
+Oak bark.
+Divi divi.
+Myrabolams.
+Valonia.
+Mimosa.
+Extracts { Oak bark and wood hemlock.
+Gambier.
+Cutch.
+
+_Germany and Austria_.
+Oak bark.
+Pine "
+Willow bark.
+Valonia.
+Knoppern.
+Myrabolams.
+         { Oak bark and wood.
+Extracts { Pine bark and wood.
+
+_Russia._
+Birch bark.
+Willow "
+Oak    "
+Pine   "
+Hemlock extract.
+
+
+_Norway and Sweden_.
+Birch bark.
+Willow "
+Oak    "
+
+                                      WALTER J. SALOMON.
+--_Shoe and Leather Reporter_.
+
+       *       *       *       *       *
+
+
+
+
+AN APPARATUS FOR HEATING SUBSTANCES IN GLASS TUBES UNDER PRESSURE.[1]
+
+[Footnote 1: Read at the meeting of the Chemical Section of the
+Franklin Institute held March 17, 1891.]
+
+By H. PEMBERTON, Jr.
+
+
+Chemists who do not happen to have in their laboratories oil or air
+baths for heating closed tubes can make an air bath at short notice
+from materials furnished by all dealers in steam fittings.
+
+_Order_:
+
+(1) One four-inch wrought iron pipe, eighteen inches out to out, with
+usual thread on each end. At about nine inches from either end this
+pipe is drilled and tapped for a one-inch nipple, in such a manner
+that a pipe introduced would pass, not on a line with the radius, but
+about half way between the axis of the four-inch pipe and its walls;
+in other words, it would be on a line with a chord of the circle.
+
+(2) One one-inch wrought iron nipple, two inches long, one-inch thread
+on one end.
+
+(3) Two four-inch malleable iron caps, drilled and tapped for a
+one-inch pipe.
+
+(4) One one-inch wrought iron pipe, twenty-four inches out to out,
+with a three-inch straight thread on each end.
+
+(5) Two one-inch iron caps. A hole, one-eighth of an inch in diameter,
+is drilled in the end of one of these caps.
+
+The above order can be given _literatim_, and will be understood by
+the dealer, who will furnish, at a trifling cost, the materials, cut
+and tapped as ordered.
+
+Fig. 1 shows how the whole is put together. The numbers on the figure
+correspond also to the numbers of the paragraphs of the order as given
+above.
+
+[Illustration: FIG. 1.]
+
+[Illustration: FIG. 2.]
+
+Fig. 2 is an end section. A cork is inserted in 2 and through it a
+thermometer, the bulb of which is on a level with the interior pipe.
+The whole is supported on a few bricks at either end, and is kept
+steady and in place by a couple of weights or half bricks. It is
+heated by one or two Bunsen burners, according to the temperature
+desired.--_Jour. Fr. Institute_.
+
+       *       *       *       *       *
+
+
+
+
+TESTING CEMENT.
+
+
+An improved method of testing Portland cement has been adopted by M.
+Deval, Chief Superintendent of Bridges and Roads, who has charge,
+under M. Saele, of the Public Works Laboratory of the City of Paris.
+The principal difference in M. Deval's method consists in the use of
+hot water for the period of hardening. The briquettes are made in the
+usual way, and of the ordinary size; and the cement to be tested is
+gauged with three times its weight of normal sand, and the smallest
+quantity of water possible. After preparation, the briquettes are
+allowed to harden in air for a period ranging from 24 hours for
+Portland cement to 30 days for certain slow-setting hydraulic limes.
+After this period, the samples are immersed in water kept at a
+temperature of 80 deg. C., in which they remain for from two to seven
+days. The briquettes are then broken in the ordinary way. After
+careful comparisons of many varieties of cement hardened hot and cold,
+M. Deval finds that cold tests are fallacious, inasmuch as they may
+fail to detect bad material. Portland cement of good quality will not
+only stand water at 80 deg. C., but will attain in seven days about the
+same strength as is reached in the cold after 28 days. The hot test
+therefore saves time. The hot test is an unfailing proof for free
+lime; cements containing this constituent betraying weakness, and
+cracking, swelling, and disintegrating in a very significant manner.
+This last result is regarded as a valuable quality of the new method
+of testing cement, the general effect of which appears to be to
+enhance the test value of really good cements, while depreciating
+those of an inferior character.
+
+       *       *       *       *       *
+
+
+THE SCIENTIFIC AMERICAN Architects and Builders Edition
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