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+The Project Gutenberg EBook of Scientific American Supplement, No. 561,
+October 2, 1886, 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. 561, October 2, 1886
+
+Author: Various
+
+Release Date: July 27, 2005 [EBook #16360]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Juliet Sutherland, Jeannie Howse, Victoria
+Woosley and the Online Distributed Proofreading Team at
+www.pgdp.net
+
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 561
+
+
+
+
+NEW YORK, OCTOBER 2, 1886
+
+Scientific American Supplement. Vol. XXII., No. 561.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+       *       *       *       *       *
+
+
+
+
+TABLE OF CONTENTS.
+
+
+I.    BOTANY.--A Century Plant in Bloom.--Interesting account of
+      the recent blossoming of an _Agave Americana_ at
+      Auburn, N.Y.                                                8965
+
+      Alpine Flowers in the Pyrenees.--1 illustration.            8965
+
+II.   CHEMISTRY.--Probable Isolation of Fluorine.--Decomposition
+      of hydrofluoric acid by an electric current.--By M.H.
+      MOISSAN.--Production of a new body, possibly fluorine, or
+      perfluoride of hydrogen.                                    8963
+
+      The Determination of Nitric Acid by the Absorption of Nitric
+      Oxide in a Standard Solution of Permanganate of Potash.--
+      By H.N. MORSE and A.F. LINN. Full description of a new and
+      important volumetric determination.--1 illustration.        8964
+
+      Water of Crystallization.--By W.W.J. NICOL, M.A., D.Sc.--
+      Discussion of the state of water of crystallization in a
+      salt in solution.                                           8964
+
+III.  ENGINEERING.--Combustion, Fire Boxes, and Steam Boilers--By
+      JOHN A. COLEMAN.--Address before the June Convention of
+      the Master Mechanics' Association.                          8953
+
+      Compound Hydraulic Presses.--Different forms of presses
+      designed for pressing bales for shipment.--Very fully
+      illustrated by 8 figures.                                   8951
+
+      Examination Papers in General Construction.--Eighty-six
+      questions in engineering propounded by the civil service
+      examiners of New York city.                                 8956
+
+IV.   MEDICINE AND PHYSIOLOGY.--A New Apparatus for the Study of
+      Cardiac Drugs.--By WILLIAM GILMAN THOMPSON, M.D.--Ingenious
+      application of instantaneous photography to the study
+      of heart movements.--Apparatus and views produced.--3
+      illustrations.                                              8966
+
+      Creosote a Specific for Erysipelas,--A new cure for this
+      complaint.                                                  8966
+
+V.    METALLURGY.--Primitive Iron Manufacture.--Iron furnace
+      and blowing apparatus in use in Bengal.--2 illustrations.   8962
+
+VI.   MINING ENGINEERING.--The Catastrophe at Chancelade.--
+      Application of photography to investigating mine disasters.
+      --4 illustrations.                                          8962
+
+VII.  MISCELLANEOUS.--Celebration of the 500th Anniversary of the
+      University of Heidelberg. August, 1886.                     8957
+
+      Useful Bags and How to Make Them.--Interesting paper on the
+      trunk makers' art.--4 illustrations.                        8960
+
+VIII. NAVAL ENGINEERING.--Atlantic Steamers.--By W. JOHN.--
+      Exhaustive comparison of representative Atlantic liners
+      and war ships.--3 illustrations.                            8954
+
+      Jet Propellers.--Hydraulic propulsion of vessels.--
+      Mathematical examination of this subject.                   8951
+
+IX.   ORDNANCE.--The New Army Gun.--Description of the 8-inch
+      steel gun as manufactured at the West Point, N.Y.,
+      Foundry.--1 illustration.                                   8952
+
+X.    PHYSICS.--A New Thermo Regulator.--1 illustration.          8959
+
+      Cohesion and Cohesion Figures.--By WILLIAM ACKROYD,
+      F.I.C.--Laws of vortex rings examined, and relation of
+      solubility to cohesion.                                     8963
+
+      Pipette for taking the Density of Liquids.--Apparatus and
+      calculations for use.--1 illustration.                      8959
+
+XI.   TECHNOLOGY.--Impurities in Photographic Chemicals, and
+      Tests for Same.--Table referred to in a paper read before
+      the Birmingham Photographic Society by G.M. Jones, M.P.S.   8957
+
+      Molasses, how made.--Work on Plantations Graphically
+      Described.*                                                 8961
+
+      Optical errors and human mistakes.--By ERNST GUNDLACH.--On
+      the examination of optical glasses.--A paper read before
+      the Buffalo meeting of the A.A.A.S.                         8963
+
+      Soap.--By HENRY LEFFMANN, Ph.D.                             8962
+
+      Somzee's New Gas Burners.--Interesting description of
+      regenerative burners.--9 figures.                           8958
+
+      The Clamond Gas Burner.--Of value as a supplement to the
+      above named article, describing an incandescent burner.
+      --1 illustration.                                           8959
+
+      Wood Oil.--A new industry worked on the large scale in
+      Sweden.                                                     8962
+
+
+         * Transcriber's Note: "Work on Plantations..." was
+           originally part of TOC entry "Optical Errors..."
+
+
+       *       *       *       *       *
+
+
+
+
+COMPOUND HYDRAULIC PRESSES.
+
+
+In a hydraulic packing press, the work done by the ram during one
+stroke may be roughly divided into two periods, in the first of which
+the resistance, although gradually increasing, may be called light,
+while in the second the resistance is heavy. The former of these two
+periods embraces the greater part of the stroke, and it is only a
+small proportion at the end which requires the exercise of the full
+power of the press to bring the material to the determined degree of
+consolidation. Consequently, if a hydraulic press is to be worked so
+as to waste no time, it requires to be provided with means by which
+its table may be made to rise rapidly during the portion of the stroke
+when the resistance is small, and afterward more slowly when the
+entire power of the pumps is being expended upon the final squeeze.
+Many methods of obtaining this end have been devised, and are in
+common use both here and abroad. It is, however, more particularly in
+the packing of raw material that such appliances are useful, since the
+goods pressed into bales in this country are not usually of a very
+yielding nature, and consequently do not require a long stroke to
+bring them to a high state of compression. In India and Egypt, from
+whence cotton is sent in bales, presses must have a long stroke; and
+unless they can be worked rapidly, a very considerable amount of plant
+is required to get through a moderate quantity of work. To meet the
+necessities of these countries, Mr. Watson has devised several forms
+of press in which not only is the table made to rise rapidly through
+the greater part of its stroke, but the rams are kept almost
+constantly in motion, so that the time occupied in filling the box
+with raw cotton and in placing the ties round the bales is not lost.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 1 and 2.]
+
+We illustrate four forms of Mr. Watson's presses, Fig. 1 being an
+earlier construction, which, although very rapid at the date at which
+it was brought out, has been far surpassed in celerity by the
+arrangements shown in Figs. 3 to 8. It was introduced in 1873, and
+forty-three presses according to this design were sent to India by the
+makers, Messrs. Fawcett, Preston & Co., of Phoenix Foundry,
+Liverpool, between that year and 1880. Four presses of this kind are
+worked by one engine, having a cylinder 20 in. by 3 ft. stroke, and
+driving eighteen to twenty pumps of varying diameter and short stroke.
+The press has two long-stroke rams, LL, of small diameter, to compress
+the loose material, and two short-stroke rams, FF, of large diameter,
+to give the final squeeze. These two pairs of rams act alternately,
+the one pair being idle while the other is in operation. The lashing
+of the bale takes place while the larger rams are in action, the bale
+being supported on the grid, B, which is pushed under it through
+grooves formed in the press-head, S (Fig. 1). When the grid is in
+place the press-head can be lowered, and the box be filled, while the
+bale is receiving its final squeeze from the inverted rams above.
+
+In Figs. 1 and 2 the press is shown in the position it would occupy if
+the bale, M, were just completed and ready to be pushed out, and the
+box, N, were full of material. The filling doors, CC, are shown turned
+back level with the floor, the main doors, AA, are open, as are also
+the end doors, KK, to admit the men to fasten up the bale. If water be
+admitted to the subsidiary cylinder, H, the head, G, and two rams, FF,
+will be raised, and then the bale, M, can be thrown out finished. All
+the doors are now closed and water admitted to the rams, LL. These
+immediately rise, pushing the contents of the box, N, before them, and
+compressing them until the table, S, reaches the level of the grid, B.
+At this moment the tappet rod, D, shuts off the water, and withdraws
+the bolt of the doors, AA, which fly open. The grid, B (Fig. 2), is
+then run through the grooves in the press-head, S, and the rams, LL,
+are allowed to descend ready for a baling cloth to be inserted through
+the doors, EE, and for the box, N, to be refilled. At the same time
+the head, G, comes down on to the bale and compresses it still
+further, while the men are at work lashing it. When the material is in
+hanks, like jute, the rams, LL, are lowered slowly, while a man
+standing inside the box, at about the level of the floor, packs the
+material neatly on the table.
+
+These presses can be worked with great rapidity, the average output
+during a day varying from 21 to 28 bales an hour. The consumption of
+coal per bale is 9 lb. of Bengal coal, in value about ¾d. The density
+of the cotton bales produced is about 45 lb. per cubic foot, 400 lb.
+measuring a little under 9 cubic feet for shipment. In the case of
+jute or jute roots, the same weight occupies 10 cubic feet on an
+average. But rapid as this press is in action, the necessities of
+recent business in India have called for still more expeditious
+working, and to meet this demand Mr. Watson produced his compound
+press, in which the economy of time is carried to its utmost
+development. By the addition of a second pair of long-stroke rams the
+output of the press has been trebled, being raised to 80 bales per
+hour. To effect this, there is one pair of powerful rams, as in the
+press just described, but two pairs of the long-stroke rams. Further,
+each pair of the small-diameter rams is fitted with two boxes, one of
+which is always being filled while the other is being pressed. The
+rams in rising compress the material into a small cell or box,
+situated above the box in which raw cotton is thrown. On the top of
+the ram head there is a loose lashing plate, which, at the finish of
+the action of the rams, is locked in the cell by bolts actuated by a
+suitable locking gear. While in this cell the bale has the lashing
+ropes put round it, and then it is placed under the large rams for the
+final squeeze, during which the ties or ropes are permanently secured.
+Thus neither of the small presses has even to wait while its box is
+being filled, or while the previously pressed bale is being lashed.
+Even in the large press, when the ties are finally fastened, the time
+occupied does not exceed three-quarters of a minute, and is often much
+less.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 3 and 4.]
+
+This press is shown in Figs. 3 and 4. The small rams are arranged at
+either side of the large ones, which, in this case, are not inverted.
+To each of the smaller presses there is a pair of boxes mounted on a
+vertical column, around which they can revolve to bring either box
+over the rain head. When the left hand rams rise, the material is
+delivered into the cell, D, which previously has had its doors (Fig.
+4) closed. To permit of the cell, D, being moved out of the way, it is
+mounted so that it can revolve on one of the columns of the main
+press, first into the position shown at B (Fig. 4), and afterward to C
+(Fig. 3). While at D, the bale in the cell (called from its
+construction a revolver) is partly lashed, the ties or ropes being put
+into position. It is then rotated until it comes over the large rams,
+where the bale is still more compressed and secured.
+
+It must be admitted that this press provides for the greatest possible
+economy of time, and for the largest output, for the capital employed,
+which can be attained. The rams and the men are constantly in action,
+and not a single moment is lost. For filling each box 78 seconds are
+allowed, and there is ample time for the preliminary lashing.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 5 and 6.]
+
+Figs. 5 and 6 show a modification of this press, designed to turn out
+sixty bales per hour. It has only one set of long-stroke rams, with
+three revolvers. The bale receives its preliminary lashing while in
+the position, B (Fig. 6). Fifty-three seconds are available for
+filling the box, and the same time for the preliminary lashing. It is
+found, however, that three-quarters of a minute is sufficient for the
+complete hooping of a bale.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 7 and 8.]
+
+Figs. 7 and 8 show a similar press intended for jute pressing. This
+has only one box, which is fixed, as the material has to be packed in
+an orderly manner. Its speed is sixty bales an hour.--_Engineering._
+
+       *       *       *       *       *
+
+
+
+
+JET PROPELLERS.--HYDRAULIC PROPULSION OF VESSELS.
+
+
+Certain mechanical devices appear to exercise a remarkable influence
+on some minds, and engineers are blamed for not adopting them, in no
+very measured terms in some cases. It is not in any way necessary that
+these devices should have been invented by the men who advocate their
+adoption, in order to secure that advocacy. The intrinsic attractions
+of the scheme suffice to evoke eulogy; and engineers sometimes find it
+very difficult to make those who believe in such devices understand
+that there are valid reasons standing in the way of their adoption.
+One such device is hydraulic propulsion. A correspondent in a recent
+impression suggested its immediate and extended use in yachts at all
+events, and we willingly published his letter, because the system does
+no doubt lend itself very freely to adoption for a particular class of
+yachts, namely, those provided with auxiliary power only. But because
+this is the case it must not be assumed that the jet propeller is
+better than screw or paddle-wheel propulsion; and it is just as well,
+before, correspondence extends further, that we should explain why and
+in what way it is not satisfactory. The arguments to be urged in favor
+of hydraulic propulsion are many and cogent; but it will not fail to
+strike our readers, we think, that all these arguments refer, not to
+the efficiency of the system, but to its convenience. A ship with a
+hydraulic propeller can sail without let or hindrance; a powerful pump
+is provided, which will deal with an enormous leak, and so on. If all
+the good things which hydraulic propulsion promises could be had
+combined with a fair efficiency, then the days of the screw propeller
+and the paddle wheel would be numbered; but the efficiency of the
+hydraulic propeller is very low, and we hope to make the reason why it
+is low intelligible to readers who are ignorant of mathematics. Those
+who are not ignorant of them will find no difficulty in applying them
+to what we have to say, and arriving at similar conclusions in a
+different way.
+
+Professor Greenhill has advanced in our pages a new theory of the
+screw propeller. As the series of papers in which he puts forward his
+theory is not complete, we shall not in any way criticise it; but we
+must point out that the view he takes is not that taken by other
+writers and reasoners on the subject, and in any case it will not
+apply to hydraulic propulsion. For these reasons we shall adhere in
+what we are about to advance to the propositions laid down by
+Professor Rankine, as the exponent of the hitherto received theory of
+the whole subject. When a screw or paddle wheel is put in motion, a
+body of water is driven astern and the ship is driven ahead. Water,
+from its excessive mobility, is incapable of giving any resistance to
+the screw or paddle save that due to its inertia. If, for example, we
+conceive of the existence of a sea without any inertia, then we can
+readily understand that the water composing such a sea would offer no
+resistance to being pushed astern by paddle or screw. When a gun is
+fired, the weapon moves in one direction--this is called its
+recoil--while the shot moves in another direction. The same
+principal--_pace_ Professor Greenhill--operates to cause the movement
+of a ship. The water is driven in one direction, the ship in another.
+Now, Professor Rankine has laid down the proposition that, other
+things being equal, that propeller must be most efficient which sends
+the largest quantity of water astern at the slowest speed. This is a
+very important proposition, and it should be fully grasped and
+understood in all its bearings. The reason why of it is very simple.
+Returning for a moment to our gun, we see that a certain amount of
+work is done on it in causing it to recoil; but the whole of the work
+done by the powder is, other things being equal, a constant quantity.
+The sum of the work done on the shot and on the gun in causing their
+motions is equal to the energy expended by the powder, consequently
+the more work we do on the gun, the less is available for the shot. It
+can be shown that, if the gun weighed no more than the shot, when the
+charge was ignited the gun and the shot would proceed in opposite
+directions at similar velocities--very much less than that which the
+shot would have had had the gun been held fast, and very much greater
+than the gun would have had if its weight were, as is usually the
+case, much in excess of that of the shot. In like manner, part of the
+work of a steam engine is done in driving the ship ahead, and part in
+pushing the water astern. An increase in the weight of water is
+equivalent to an augmentation in the weight of our gun and its
+carriage--of all that, in short, takes part in the recoil.
+
+But, it will be urged, it is just the same thing to drive a large body
+of water astern at a slow speed as a small body at a high speed. This
+is the favorite fallacy of the advocates of hydraulic propulsion. The
+turbine or centrifugal pump put into the ship drives astern through
+the nozzles at each side a comparatively small body of water at a very
+high velocity. In some early experiments we believe that a velocity of
+88 ft. per second, or 60 miles an hour, was maintained. A screw
+propeller operating with an enormously larger blade area than any pump
+can have, drives astern at very slow speed a vast weight of water at
+every revolution; therefore, unless it can be shown that the result is
+the same whether we use high speed and small quantities or low speed
+and large quantities, the case of the hydraulic propeller is hopeless.
+But this cannot be done. It is a fact, on the contrary, that the work
+wasted on the water increases in a very rapid ratio with its speed.
+The work stored up in the moving water is expressed in foot pounds by
+the formula
+
+  W v² / 2g
+
+where W stands for the weight of the water, and v for its velocity.
+But the work stored in the water must have been derived from the
+engine; consequently the waste of engine power augments, not in the
+ratio of the speed of the water, but in the ratio of the square of its
+speed. Thus if a screw sends 100 tons of water astern at a speed of 10
+ft. per second per second, the work wasted will be 156 foot tons per
+second in round numbers. If a hydraulic propeller sent 10 tons astern
+at 100 ft. per second per second, the work done on it would be 1,562
+foot tons per second, or ten times as much. But the reaction effort,
+or thrust on the ship, would be the same in both cases. The waste of
+energy would, under such circumstances, be ten times as great with the
+hydraulic propeller as with the screw. In other words, the slip would
+be magnified in that proportion. Of course, it will be understood that
+we are not taking into account resistances, and defects proper to the
+screw, from which hydraulic propulsion is free, nor are we considering
+certain drawbacks to the efficiency of the hydraulic propeller, from
+which the screw is exempt; all that we are dealing with is the waste
+of power in the shape of work done in moving water astern which we do
+not want to move, but cannot help moving. If our readers have followed
+us so far, they will now understand the bearing of Rankine's
+proposition, that that propeller is best which moves the greatest
+quantity of water astern at the slowest speed. The weight of water
+moved is one factor of the thrust, and consequently the greater that
+weight, other things being equal, the greater the propelling force
+brought to bear on the ship.
+
+It may be urged, and with propriety, that the results obtained in
+practice with the jet propeller are more favorable than our reasoning
+would indicate as possible; but it will be seen that we have taken no
+notice of conditions which seriously affect the performance of a
+screw. There is no doubt that it puts water in motion not astern. It
+twists it up in a rope, so to speak. Its skin frictional resistance is
+very great. In a word, in comparing the hydraulic system with the
+normal system, we are comparing two very imperfect things together;
+but the fact remains, and applies up to a certain point, that the
+hydraulic propeller must be very inefficient, because it, of all
+propellers, drives the smallest quantity of water astern at the
+highest velocity.
+
+There is, moreover, another and a very serious defect in the hydraulic
+propeller as usually made, which is that every ton of water passed
+through it has the velocity of the ship herself suddenly imparted to
+it. That is to say, the ship has to drag water with her. To illustrate
+our meaning, let us suppose that a canal boat passes below a stage or
+platform a mile long, on which are arranged a series of sacks of corn.
+Let it further be supposed that as the canal boat passes along the
+platform, at a speed of say five miles an hour, one sack shall be
+dropped into the boat and another dropped overboard continuously. It
+is evident that each sack, while it remains in the boat, will have a
+speed the same as that of the boat, though it had none before. Work
+consequently is done on each sack, in overcoming its inertia by
+imparting a velocity of five miles an hour to it, and all this work
+must be done by the horse towing on the bank. In like manner the
+hydraulic propeller boat is continually taking in tons of water,
+imparting her own velocity to them, and then throwing them overboard.
+The loss of efficiency from this source may become enormous. So great,
+indeed, is the resistance due to this cause that it precludes the
+notion of anything like high speeds being attained. We do not mean to
+assert that a moderate degree of efficiency may not be got from
+hydraulic propulsion, but it can only be had by making the quantity of
+water sent astern as great as possible and its velocity as small as
+possible. That is to say, very large nozzles must be employed. Again,
+provision will have to be made for sending the water through the
+propeller in such a way that it shall have as little as possible of
+the motion of the ship imparted to it. But as soon as we begin to
+reduce these principles to practice, it will be seen that we get
+something very like a paddle wheel hung in the middle of the boat and
+working through an aperture in her hull, or else a screw propeller put
+into a tube traversing her from stem to stern.
+
+We may sum up by saying that the hydraulic propeller is less efficient
+than the screw, because it does more work on the water and less on the
+boat; and that the boat in turn does more work on the water than does
+one propelled by a screw, because she has to take in thousands of tons
+per hour and impart to them a velocity equal to her own. Part of this
+work is got back again in a way sufficiently obvious, but not all. If
+it were all wasted, the efficiency of the hydraulic propeller would be
+so low that nothing would be heard about it, and we certainly should
+not have written this article.--_The Engineer._
+
+       *       *       *       *       *
+
+
+
+
+THE NEW ARMY GUN.
+
+
+The cut we give is from a photograph taken shortly after the recent
+firings. The carriage upon which it is mounted is the one designed by
+the Department and manufactured by the West Point Foundry, about six
+months since. It was designed as a proof carriage for this gun and
+also for the 10 inch steel gun in course of construction. It is
+adapted to the larger gun by introducing two steel bushing rings
+fitted into the cheeks of carriage to secure the trunnion of the gun.
+
+The gun represented is an 8 inch, all steel, breech-loading rifle,
+manufactured by the West Point Foundry, upon designs from the Army
+Ordnance Bureau. The tube and jacket were obtained from Whitworth, and
+the hoops and the breech mechanism forgings from the Midvale Steel
+Company. The total weight of the gun is 13 tons; total length,
+including breech mechanism, 271 inches; length of bore in front of gas
+check, 30 calibers; powder space in chamber, 3,109 cubic inches;
+charge, 100 pounds. The tube extends back to breech recess from
+muzzle, in one solid piece. The breech block is carried in the jacket,
+the thread cut in the rear portion of the jacket. The jacket extends
+forward and is shrunk over the tube about 87½ inches. The re-enforce
+is strengthened by two rows of steel hoops; the trunnion hoops form
+one of the outer layers. In front of the jacket a single row of hoops
+is shrunk on the tube and extends toward the muzzle, leaving 91 inches
+of the muzzle end of the tube unhooped. The second row of hoops is
+shrunk on forward of the trunnion hoops for a length of 38 inches to
+strengthen the gun, and the hoop portion forms three conical frustums.
+The elastic resistance of the gun to tangential rupture over the
+powder chamber is computed by Claverino and kindred formulas to be
+54,000 lb. per square inch.
+
+[Illustration: THE ARMY 8 INCH STEEL GUN WITH CARRIAGE.]
+
+The breech mechanism is modeled after the De Bange system. The block
+has three smooth and three threaded sectors, and is locked in place by
+one-sixth of a turn of a block, and secured by the eccentric end of a
+heavy lever, which revolves into a cut made in the rear breech of the
+gun. The gas check consists of a pad made of two steel plates or cups,
+between which is a pad of asbestos and mutton suet formed under heavy
+pressure. The rifling consists of narrow grooves and bands, 45 of
+each. The depth of the groove is six one-hundredths of an inch.
+
+Although the gun is designed for a charge of 100 pounds, it is
+believed that it can be increased to 105 pounds without giving
+dangerous pressure, and the intention is to increase the charge to
+that amount when the new powder is received from Du Pont.
+
+The following is a very full synopsis of the official report of the
+preliminary firings--13 rounds--with this gun:
+
+The first seven rounds were fired with German cocoa powder, which was
+received from Watervliet Arsenal. There were two kinds of cartridges,
+one kind weighing 85 pounds, and having 30 grains in each layer, the
+other weighing 100 lb., and having 27 grains in each layer. In two of
+the first seven rounds the weight of the charge was 65 pounds, the
+projectiles weighing 182 and 286 pounds; in the next two rounds
+charges of 85 pounds were fired, the projectiles, as before, weighing
+182 and 286 pounds, while in the last three of the rounds fired with
+cocoa powder the charge was 100 lb., while the weight of the
+projectile was 182, 235, and 286 pounds. At the seventh round was
+fired the normal charge, 100 lb. of powder and a projectile weighing
+286 pounds, for which the gun was designed. The mean pressure for this
+round, determined by two crusher gauges, was 32,800 pounds, and the
+velocity at 150 feet was 1,787 feet.
+
+Two kinds of Du Pont's brown prismatic powder, marked P.A. and P.I.,
+were then fired. With the normal charge of P.A. powder (round 12 of
+the record), the mean pressure was 35,450 pounds, the velocity at 150
+feet was 1,812 feet. For P.I. powder (round 13 of the record), the
+pressure was 26,925 pounds, the velocity was 1,702 feet, and a
+considerable amount of unconsumed powder was ejected, showing that the
+P.I. powder is not a suitable one for this piece. The highest pressure
+indicated with the normal charge of P.A. powder was 36,200 pounds,
+exceeding by 1,200 pounds the provisional limit of pressure.
+
+At the fifth round the breech block opened with some difficulty, and
+an examination showed that the resistance resulted from the diametral
+enlargement of the rear plate. Directions have been given to correct
+this defect. The star gauge records show that no material change took
+place in the diameter of the chamber or the bore. From 30 inches to 54
+inches (measured from base of the breech), there was a diminution in
+diameter of from 0.001 in. to 0.002 in.; in rear of 30 inches there
+was no change. No enlargement in the shot chamber exceeded 0.001 in.
+From the bottom of the bore (the beginning of the rifling) to the
+muzzle the average enlargements were as follows: in. to 6 in., 0.005
+in.; 7 in. to 14 in., 0.003 in.; 15 in. to 29 in., 0.002 in.; 30 in.
+to muzzle, 0.002 to 0.001 in.
+
+After the third round the joint between the D. and D. rings opened
+slightly on the top, and measured after the 13th round showed that the
+opening was about 0.004 in. wide. It cannot at present be stated
+whether or not this opening increased during firing, but the defect
+has been noted and will be carefully observed. Enough cocoa powder
+remains to allow a comparison to be made with such brown prismatic
+powder as may be adopted finally. No firing has been done as yet to
+test the best position for the bands, but it will take place as soon
+as enough of some standard powder is obtained to fire ten consecutive
+rounds.--_Army and Navy Journal._
+
+       *       *       *       *       *
+
+
+
+
+COMBUSTION, FIRE-BOXES, AND STEAM BOILERS.[1]
+
+  [Footnote 1: Address before the June Convention of the Master
+  Mechanics' Association.]
+
+By JOHN A. COLEMAN.
+
+
+Mr. Chairman and gentlemen: I was rash enough some time ago to promise
+to prepare a paper for this occasion, the fulfillment of which prior
+engagements have absolutely prevented.
+
+I would greatly prefer to be let off altogether, but I do not like to
+break down when expected to do anything; and if you have the patience
+to listen for a few minutes to the reflections of an "outsider," I
+will endeavor to put what I have to say in as concise form as I can,
+in such manner as will do no harm, even if it does no good.
+
+For many years I was connected with steam engineering. I was once with
+the Corliss Steam Engine Company, and afterward was the agent of Mr.
+Joseph Harrison, of Russian fame, for the introduction of his safety
+boilers.
+
+That brought me into contact with the heavy manufacturers throughout
+the Eastern States, and during that long experience I was particularly
+impressed with a peculiarity common to the mill owners, which, I
+believe it may be said with truth, is equally common to those
+interested in locomotive engineering, namely, how much we overlook
+common, every-day facts. For instance, we burn coal; that is, we think
+we do, and boilers are put into mills and upon railroads, and we
+suppose we are burning coal under them, when in reality we are only
+partially doing so. We think that because coal is consumed it
+necessarily is burned, but such is frequently very far from the fact.
+
+I wish upon the present occasion to make merely a sort of general
+statement of what I conceive to be combustion, and what I conceive to
+be a boiler, and then to try to make a useful application of these
+ideas to the locomotive.
+
+Treating first the subject of combustion, let us take the top of the
+grate-bars as our starting point. When we shovel coal upon the grate
+bars and ignite it, what happens first? We separate the two
+constituents of coal, the carbon from the hydrogen. We make a gas
+works. Carbon by itself will burn no more than a stone; neither will
+hydrogen. It requires a given number of equivalents of oxygen to mix
+with so many equivalents of carbon, and a given number of equivalents
+of oxygen to mix with so many of hydrogen to form that union which is
+necessary to produce heat. This requires time, space, and air, and one
+thing more, viz., heat.
+
+I presume that most of you have read Charles Williams' treatise upon
+"Combustion," which was published many years ago, and which until
+recently was often quoted as an absolute authority upon the art of
+burning fuel under boilers. Mr. Williams in his treatise accurately
+describes the chemistry of combustion, but he has misled the world for
+fifty years by an error in reasoning and the failure to discuss a
+certain mechanical fact connected with the combination of gases in the
+process of combustion. He said: "What is the use of heating the air
+put into a furnace? If you take a cubic foot of air, it contains just
+so many atoms of oxygen, neither more nor less. If the air be heated,
+you cause it to assume double its volume, but you have not added a
+single atom of oxygen, and you will require twice the space for its
+passage between the grate bars, and twice the space in the furnace,
+which is a nuisance; but if the air could be frozen, it would be
+condensed, and more atoms of oxygen could be crowded into the cubic
+foot, and the fire would receive a corresponding advantage." Mr.
+Williams proceeded upon this theory, and died without solving the
+perplexing mystery of as frequent failure as success which attended
+his experiments with steamship boilers. The only successes which he
+obtained were misleading, because they were made with boilers so badly
+proportioned for their work that almost any change would produce
+benefit.
+
+Successful combustion requires something more than the necessary
+chemical elements of carbon, hydrogen, and oxygen, for it requires
+something to cook the elements, so to speak, and that is heat, and for
+this reason: When the coal is volatilized in the furnace, what would
+be a cubic foot of gas, if cold, is itself heated and its volume
+increased to double its normal proportion. It is thin and attenuated.
+The cold air which is introduced to the furnace is denser than the
+gas. With dampers wide open in the chimney, and the gases and air
+passing into the flues with a velocity of 40 feet per second, they
+strike the colder surface of the tubes, and are cooled below the point
+of combustion before they have had time to become assimilated; and
+although an opponent in a debate upon steam boiler tests once stated
+that his thermometer in the chimney showed only 250 degrees, and
+indicated that all the value that was practical had been obtained from
+the coal, I took the liberty to maintain that a chemist might have
+analyzed the gases and shown there were dollars in them; and that if
+the thermometer had been removed from the chimney and placed in the
+pile of coal outside the boiler, it would have gone still lower; but
+it would not have proved the value to have been extracted from the
+coal, for it was not the complete test to apply.
+
+The condition of things in the furnace may be illustrated thus: If we
+should mingle a quart of molasses and a gallon of water, it would
+require considerable manipulation and some time to cause them to
+unite. Why? Because one element is so much denser than the other; but
+if we should mix a quart of the gallon of water with the quart of
+molasses, and render their densities somewhere near the density of the
+remaining water, and then pour the masses together, there would be a
+more speedy commingling of the two. And so with the furnace. I have
+always maintained that every furnace should be lined with fire-brick,
+in order that it shall be so intensely hot when the air enters that
+the air shall instantly be heated to the same degree of tenuity as the
+hot gases themselves, and the two will then unite like a flash--and
+that is heat. And here is the solution of the Wye Williams mystery of
+failure when cold air was introduced upon the top of a fire to aid
+combustion. The proof of the necessity for heat to aid the chemical
+assimilation of the volatilized coal elements is seen in starting a
+fire in a common stove. At first there is only a blue flame, in which
+the hand may be held; but wait until the lining becomes white hot, and
+then throw on a little coal, and you will find a totally different
+result. It is also seen in the Siemens gas furnace, with which you are
+doubtless familiar. There is the introduction of gas with its
+necessary complement of air. Until the furnace and retorts become
+heated, the air and gas flutter through only partially united, and do
+little good; but as soon as the retorts and furnace become thoroughly
+hot, the same gas and air will melt a fire-brick.
+
+These are common phenomena, which are familiar, but apt to be
+unnoticed; but they logically point to the truth that no furnaces
+should present a cooling medium in contact with fuel which is
+undergoing this process of digestion, so to speak. It will be very
+evident, I think, from these facts that water-legs in direct contact
+with a fire are a mistake. They tend to check a fire as far as their
+influence extends, as a thin sheet of ice upon the stomach after
+dinner would check digestion, and for the same reason, namely, the
+abstraction of heat from a chemical process. If fire-brick could be
+laid around a locomotive furnace, and the grate, of course, kept of
+the same area as before, it is my belief that a very important
+advantage would be at once apparent. An old-fashioned cast iron heater
+always produced a treacherous fire. It would grow dead around the
+outside next to the cold iron; but put a fire-clay lining into it, and
+it was as good as any other stove.
+
+If I have now made clear what I mean by making heat, we will next
+consider the steam boiler. What is a steam boiler? It is a thing to
+absorb heat. The bottom line of this science is the bottom of a pot
+over a fire, which is the best boiler surface in the world; there is
+water upon one side of a piece of iron and heat against the other. One
+square foot of the iron will transmit through it a given number of
+units of heat into the water at a given temperature in a given time;
+two square feet twice as many, and three, three times as many, and so
+on. Put a cover upon the pot, and seal it tight, leave an orifice for
+the steam, and that is a steam boiler with all its mysteries.
+
+The old-fashioned, plain cylinder boiler is a plain cylindrical pot
+over the fire. If enough plain cylinder boilers presenting the
+requisite number of square feet of absorbing surface are put into a
+cotton mill, experience has shown that they will make a yard of cotton
+cloth about as cheaply as tubular boilers. If this is so, why do not
+all put them in? Because it is the crudest and most expensive form of
+boiler when its enormous area of ground, brickwork, and its fittings
+are considered. Not all have the money or the room for them. To
+produce space, the area is drawn in sidewise and lengthwise, but we
+must have the necessary amount of square feet of absorbing surface,
+consequently the boiler is doubled up, so to speak, and we have a
+"flue boiler." We draw in sidewise and lengthwise once more and double
+up the surface again, and that is a "tubular boiler." That includes
+all the "mystery" on that subject.
+
+Now, we find among the mills, just as I imagine we should upon the
+railroads, that the almost universal tendency is to put in too small
+boilers and furnaces. To skimp at boilers is to spend at the coal
+yard. Small boilers mean heavy and over-deep fires, and rapid
+destruction of apparatus. In sugar houses you will see this frequently
+illustrated, and will find 16 inch fires upon their grates.
+
+We have found that, as we could persuade mill owners to put in more
+boilers and extend their furnaces, so that coal could be burned
+moderately and time for combustion afforded, we often saved as high as
+1,000 tons in a yearly consumption of 4,000.
+
+Now, when the ordinary locomotive sends particles of coal into the
+cars in which I am riding, I do not think it would be unfair criticism
+to say that the process of combustion was not properly carried out.
+When we see dense volumes of gas emitted from the stack, it is evident
+that a portion of the hard dollars which were paid for the coal are
+being uselessly thrown into the air; and it will be well to remember
+that only a little of the unburnt gas is visible to the eye.
+
+One point I wish to make is this: We find, as I have said, that as we
+spread out with boilers and furnaces in the mills, so that we can take
+matters deliberately, we save money.
+
+Now, coming again to locomotives. I think, if we examine the subject
+carefully, the fact will strike us a little curiously. The first
+locomotive built in Philadelphia weighed about 14 tons. Judging from
+the cut I have seen, I should think her furnace might have been 30
+inches square. We have gone from that little 14 ton engine to machines
+of 50 and 60 tons--perhaps more. The engines have been increased over
+four times, but I will ask you if the furnace areas have been
+increased (applause) in proportion? Some of the furnaces of the
+engines are six feet by three, but that is an increase of less than 3
+to 1 of furnace, as against 4 to 1 of weight of engine.
+
+When my attention was first called to this matter, I had supposed, as
+most people do who are outside of the railway profession, that there
+was something subtile and mysterious about railway engineering that
+none but those brought up to the business could understand. Possibly
+it is so, and I am merely making suggestions for what they are worth,
+but I think the position I have taken in this matter was established
+by some experiments of three weeks' duration, which I conducted
+between Milan and Como, in Italy, for the Italian government, in
+pulling freight trains up grades of 100 feet to the mile. The
+experiments were made with an engine built by the Reading Railroad.
+
+We competed with English, French, Belgian, and Austrian engines. These
+machines required the best of fuel to perform the mountain service,
+and could use coal dust only when it was pressed into brick. We used
+in the Reading Railroad machine different fuels upon different days,
+making the road trip of 120 miles each day with one kind of fuel. We
+used coal dust scraped up in the yards, also the best Cardiff coal,
+anthracite, and five kinds of Italian lignite, the best of which
+possesses about half the combustible value of coal.
+
+The results in drawing heavy freight trains were equally good with
+each fuel, the engine having at all times an abundance of steam on
+heavy grades, no smoke nor cinders, and no collection of cinders in
+the forward part of the engine.
+
+The fireman arranged his fires at a station, and did little or nothing
+except to smoke his pipe and enjoy the scenery until he reached the
+next station. An incident occurred to prove that we were not playing
+with the machine. They told me one morning that we should be given a
+load of 25 per cent less than the maximum load of an engine of her
+class (30 tons). We started up the 100 foot grade, and found we could
+barely crawl, and our engineer got furious over it. He thought they
+were repeating a trick already attempted by screwing down a brake in
+ascending a grade. We detected it, however, and found a pair of wheels
+nearly red hot. Upon this occasion we found nothing amiss, except full
+cars where they had reported only a light load. We pulled to the top
+of the hill, the steam blowing off furiously all the time.
+
+This was a new experience to the Italians, and might surprise some
+Americans. When we arrived at the station, the inspector-general and
+his corps of engineers were evidently amazed, and it was evident we
+had captured them. He said to me, "I can congratulate you, signor, on
+possession of a superb machine."
+
+Afterward one of the engineers said to me: "Do not let it be known
+that I told you what you have hauled or I shall lose my place, but you
+have drawn 50 per cent more than the maximum load of one of our 40 ton
+engines." I said: "You attempted to 'stall' us, and when you try it
+again, be fair enough to give me a flat of pig iron, and as you pack
+cars on one end I will pack pig iron upon the engine until she will
+stick to the track, but rest assured that you will not be able to get
+that steam down." The experience with that engine proves conclusively
+to my mind that the general principles of steam making are the same
+for both stationary and locomotive practice. The grand secret of the
+success of that Wootten engine was the enormous area of the grate
+surface, being, if I remember correctly, 7 by 9 feet, permitting thin
+fires to be carried and complete combustion to be obtained before the
+gases reached the boiler tubes. An enormous crown sheet was presented,
+and that is where the bulk of the work of any boiler is done.
+
+Thin fires accomplish this. As already stated, a given amount of coal
+generates a given amount of gas, and this gas requires a given amount
+of air or oxygen. This air must be supplied through the grate bars and
+then pass through the interstices of the mass of heated coal. It
+requires about 10 cubic feet of air to consume one cubic foot of gas.
+In stationary boilers we find that if we use "pea" and "dust" coal, an
+extremely thin layer must be used, or the 10 feet of air per foot of
+gas cannot pass through it; if "chestnut" coal be used, the thickness
+may be increased somewhat; "stove size" allows a thickness of six
+inches, and "lump" much thicker, if any wise man could be found who
+would use that coarse, uneconomical size. Of course, I am speaking of
+anthracite coal. Opinions differ about "soft coal," but the same
+general principle applies as regards an unobstructed passage of air
+through the hot bed of coal.
+
+Now, it will be agreed that the locomotive of the future must be
+improved to keep up with the times. Fierce competition requires
+increased efficiency and reduced expenses. I am told by you railroad
+gentlemen that the freight business of the country doubles every ten
+years. Trains follow close upon each other. What are you going to do?
+Are you to double, treble, or quadruple your tracks?
+
+It seems to me much remains yet to be done with the locomotive. We
+must burn a great deal less coal for the steam we make, and after we
+have made steam we must use that steam up more thoroughly. In the
+short cylinder required by locomotive service, the steam, entering at
+the initial pressure pushes the piston to the opposite end, and it
+then rushes out of the exhaust strong enough to drive another piston.
+Of every four dollars' worth of coal consumed, at least two dollars
+worth is absolutely thrown away. Or, of every ten thousand dollars
+spent for fuel, five thousand dollars are absolutely wasted. How can
+we save this? It would seem obvious that if steam rushes from the
+exhaust of an engine strong enough to drive another engine, the common
+sense of the thing would be to put another engine alongside and let
+the steam drive it, and we should get just so much more out of our
+four dollars' worth of coal. It seems evident that we must follow the
+lead of the steamship men, and compound the locomotive engine, as
+they have done with the marine engine.
+
+Next we must attack the extravagant furnace, and increase its area and
+reduce the depth of the bed of coal. The difficulty of making this
+change seemed to me to be removed, on examining an engine on the
+Providence & Bristol Railroad, the other day. The machine was made at
+the Mason Works, of Taunton. It was an engine and tender combined, the
+truck being at the rear end of the tender, and the driver placed well
+in advance of the fire-box, so that the maximum weight of both engine
+and tender rested upon the drivers. In thus removing the drivers from
+the proximity of the fire-box, abundant facility is afforded for
+widening the fire-box, so as to obtain a grate area as large as that
+of the Wootten engine or of a stationary boiler. It seems to me the
+increase of grate area can be obtained only by widening; for a length
+of more than six or seven feet is very hard upon the fireman. You
+certainly cannot get more power by deepening present fire-boxes,
+except by an enormously increased waste of fuel, which all will
+concede is already sufficiently extravagant.
+
+In arriving at the conclusion of these hasty and I fear somewhat
+incoherent remarks, I would say that the object aimed at for the
+improvement of the locomotive would be reached, first, by making steam
+economically, by employing such increased grate area as will permit
+running thin fires and moderate or comparatively slow draught; and,
+secondly, in economically using the steam which has been economically
+made by compounding the engine.
+
+I have given you merely the views of an "outsider," who has had a
+somewhat extensive experience in stationary engineering, and who has
+observed locomotive practice in many parts of the world. These views
+are offered for what they are worth, as suggestions for future thought
+in designing engines, and as a sort of refresher upon rudimentary
+points which long familiarity with every-day phenomena causes us at
+times to overlook. I trust that your deliberations may aid in the
+speedy reduction of the expenses of transporting freight and
+passengers, for the benefit of the railroad companies and, in their
+turn, the advantage of the people at large.
+
+       *       *       *       *       *
+
+
+
+
+ATLANTIC STEAMERS.[1]
+
+  [Footnote 1: A paper recently read before the Institution of Naval
+  Architects.]
+
+By W. JOHN.
+
+
+[Illustration: Fig. 1--CITY OF ROME.]
+
+The author said that he hoped to bring before the meeting impartially
+certain facts which might be of interest, and which, when recorded in
+the pages of the "Transactions," might be found of some use as data
+for future reference. In dealing with passenger steamers, he would do
+so principally from a shipbuilder's point of view; but the moment he
+commenced to think over Atlantic passenger ships as a shipbuilder, he
+was met by the question whether the present tendency toward divorcing
+the passenger and cargo trade from each other is likely to continue or
+not. If the answer is yes, then it seems to become an important
+question, for the present at least, how to build, on moderately small
+dimensions, the fastest, safest, and most economical passenger
+steamer, using all the most modern improvements to make her commodious
+and luxurious, and an easy sea boat into the bargain. If cargo is
+still to be carried in the passenger ships of the future, a moderate
+speed only will be aimed at in the immediate future, and every effort
+will be devoted to economy of fuel, comfort, and safety, with a fair
+carrying capacity. This latter policy is one which may possibly
+prevail at least for a time, as it has powerful supporters in
+Liverpool; but he could not help thinking that very high
+speeds--higher than we have yet attained--must eventually gain the
+day. He also thought that they were on the eve of important movements,
+which will indicate what the next step in the passenger trade is to
+be; for it must be remembered, among other things, that none of our
+present English transatlantic liners, even the latest, have yet been
+fitted with the latest modern improvements for economy of fuel or
+quick combustion, such as triple expansion engines or forced draught.
+They must, therefore, be at some disadvantage, other things being
+equal, compared with the ships of the future possessing them. The
+Great Eastern steaming up Milford Haven about twenty-five years ago
+between two lines of the channel fleet of old--two and three decked
+wooden line-of-battle ships--the whole fleet saluting with yards
+manned, was a sight to be remembered. More than this, that ship, with
+all her mournful career, has been a useful lesson and a useful warning
+to all naval architects who seriously study their profession--a lesson
+of what can be done in the safe construction of huge floating
+structures, and a warning that the highest flights of constructive
+genius may prove abortive if not strictly subordinated to the
+practical conditions and commercial requirements of the times. The
+Sirius and Great Western crossed the Atlantic in 1838, and in 1840 the
+first ship of the since celebrated Cunard Company made her first
+voyage. This was the Britannia, which, with her sister ships, the
+Arcadia, Caledonia, and Columbia, kept up the mail service regularly
+at a speed of about 8½ knots an hour. The Britannia was 207 ft. in
+length between perpendiculars, and 34 ft. 4 in. extreme breadth, 22
+ft. 6 in. depth of hold, 423 horse power--nominal--and 1,153 tons
+burden, built of wood, and propelled by paddles. In 1860 the Collins
+Line started in opposition to the Cunard, and, after a series of
+disasters, collapsed in 1858. This was three years after the Persia,
+the first Cunarder built of iron, had been completed. In 1850, also,
+the Inman Line was started with the City of Glasgow, of 1,600 tons
+builders' measurement, and 350 horse power. She was built of iron, and
+was the first screw steamer sent across the Atlantic from Liverpool
+with passengers, and was the pioneer of the great emigrant trade which
+Mr. Inman, above all others, did so much to develop and make cheap and
+comfortable for the emigrants themselves, as well as profitable to his
+company. That the builders of the celebrated old Great Britain, in
+1843, and Mr. Inman, in 1850, should have pronounced so decisively in
+favor of the screw propeller in preference to the paddle for ocean
+steaming is a proof of their true practical judgment, which time and
+practical experience have made abundantly clear. While the Cunard
+Company went on developing its fleet from the early wood paddle
+steamer Britannia of 1,130 tons in 1840 to the iron paddle steamers
+Persia, etc., in 1858, the iron screw steamer China of 1862, to the
+still more important screw steamers Bothnia and Scythia, vessels of
+4,335 tons, in 1874, the Inman and other lines were as rapidly
+developing in speed and size, if not in numbers. The year 1874 is
+memorable, for it saw the White Star steamers Britannic and Germanic
+put into the water, as well as the Inman steamer City of Berlin and
+the two before mentioned Cunard steamers, Bothnia and Scythia. By the
+addition of these two ships to their fleet the White Star Line,
+although started only in 1870, reached a front rank position in the
+New York passenger trade. The author gave in separate tables the logs
+of several of these ships, some from published documents and some
+kindly furnished by the owners. The Great Western had crossed the
+Atlantic from Bristol to New York in 15 days as early as 1838. The
+first Cunard steamer, the Britannic, was about the same speed, from 8¼
+to 8½ knots an hour. The average duration of the Cunard voyages in the
+year 1856 was 12.67 days from Liverpool to New York, and 11.03 days
+from New York to Liverpool. The Bothnia, in 1874, reduced the passage
+to about nine days. The White Star Britannic, in 1876, averaged 7 days
+18 hours 26 minutes outward from Queenstown to New York, and 9 days 6
+hours 44 minutes homeward, and has averaged for the last ten years 8
+days 9 hours 36 minutes outward, and 8 days 1 hour 48 minutes
+homeward. The City of Berlin, of the Inman Line, also built in 1874, 8
+days 10 hours 56 minutes, and homeward 8 days 2 hours 37 minutes; and
+for the nine years from 1875 to 1883 inclusive, averaged outward 8
+days 19 hours 56 seconds, and inward 8 days 8 hours 34 seconds; or,
+putting it into rounder figures, the Britannic had reduced the average
+passage between the two points to 8¼ days, and the City of Berlin to
+8½ days. From the year 1874 on to 1879 no further advance was made in
+Atlantic steaming, but in that year the Arizona was added to the Guion
+Line, and it soon became evident that another important stride had
+been made in the Atlantic passenger trade, which would lead to most
+important results. The results, as we all know, have been sufficiently
+startling. The Guion Line, which had started in 1866 with the
+Manhattan, had now the fastest passenger ship on the Atlantic. In
+spite of burning some fifty per cent. more coal than the Britannic,
+the ship was an obvious commercial success. The spirited policy which
+brought her into existence was appreciated by the public, and the
+other lines had to move forward. Then followed a period of rivalry,
+the Cunard Company building the Gallia and Servia, the Inman Company
+the City of Rome, and the Guion Line the Alaska, all of which were
+completed in 1881, and afterward the Oregon for the Guion
+Line--1883--the Aurania the same year for the Cunard Company, and,
+later still, the America for the National Line, and the Umbria and
+Etruria for the Cunard Company in 1885.
+
+[Illustration:
+
+_Frames from outer edge of Tank to Upper Deck, 7 × 3½ × 8/16 for 250
+ft. Amidships, for 60 ft. before and abaft these Points 6½ × 3½ × 6/16
+at end of Vessel 5 × 3½ × 7/16, all spaced 24 in. apart and all
+carried to Upper Deck, double from Bilge to Bilge in way of
+Engines.--Frames in Tank on Lattice and Solid Floors, 5 × 3½ × 8/16,
+Intermediate Frames, 8 × 4 × 9/16--Rev: Frames, 4½ × 3½ × 8/16,
+carried to Upper and Main Deck alternately double, 4½ × 4½ × 8/16 from
+Bilge to Bilge in E and B space._
+
+Fig. 2--SERVIA.]
+
+Since the completion of the Etruria, for various reasons there has
+been a pause in the tremendous strides made since 1879, and we may
+briefly review the results. Taking the Britannic as a standard with
+her ten years' average of 8¼ days across, and her quickest passage of
+7 days 10 hours 53 seconds, we have now the following steamers of
+higher speeds. Taking them in the order of their absolutely fastest
+passage out or home, they stand thus:
+
+
+TABLE I.
+
+  ---+-------------------------+------+-------+------
+     |                         | Days.| Hours.| Mins.
+     |                         +------+-------+------
+   1 | Etruria.                |   6  |   5   |  31
+   2 | Umbria (sister ship).   |   slightly longer.
+   3 | Oregon.                 |   6  |  10   |  35
+   4 | America.                |   6  |  13   |  44
+   5 | City of Rome.           |   6  |  18   |   0
+   6 | Alaska.                 |   6  |  18   |  37
+   7 | Servia.                 |   6  |  23   |  55
+   8 | Aurania.                |   7  |   1   |   1
+  ---+-------------------------+------+-------+------
+
+It will thus be seen that from the 15 days' passage or thereabout, of
+the earliest Atlantic steamers, we had got down in the days of the
+Scotia to about 9 days; in the Britannic to 8¼ days, and, at the
+present time, we have got to 6¼ days, with seven ships afloat that
+have done the passage under seven days, and capable of making their
+average passages range between 6½ and 7¼ days.
+
+Ranged in order of gross tonnage, these eight vessels stand as
+follows:
+
+
+TABLE II.
+
+  1. City of Rome.    8,144
+  2. Oregon.          7,375
+  3. Aurania.         7,269
+  4. Servia.          7,212
+  5. Umbria.          7,129
+  6. Etruria.         7,100
+  7. Alaska.          6,586
+  8. America.         5,528
+
+Here the America shows to advantage, for while being eighth in size
+she is fourth in point of speed, and from what the author can learn,
+although he had no authenticated details on the subject, he believed
+she is economical in coal consumption. He might perhaps be permitted
+to say that one of the most difficult subjects in connection with the
+propulsion of ships on which to get absolutely accurate data is that
+of coal consumption. The records of six to eight hours' trials for the
+purpose of ascertaining the coal consumption are absolutely worthless,
+as all shipbuilders and engineers know, and so far as English ships
+are concerned they are never attempted. Foreign owners frequently
+stipulate for such trials in their contracts with English
+shipbuilders, and get wonderfully economical results on paper, but the
+fact that the trials only extend over a few hours renders them
+valueless, however carefully the coal may be weighed during that
+period. An authentic record of the absolute quantity of coal consumed,
+say by each of the eight fastest Atlantic liners, together with their
+average indicated horse power on the voyage, for a series of voyages,
+would be extremely valuable.
+
+He gave, in Table III., the consumption per indicated horse power per
+hour for a number of ships. This table affords valuable data, for it
+gives, in addition to the dimensions, the moulded draught of water,
+the midship area, the displacement, the indicated horse power, the
+speed on trial, the coefficients for the lines both from the block or
+parallelopipedon, and also from the midship section prism, together
+with the length and angle of entrance obtained by Kirk's rule, the
+Admiralty displacement coefficient, together with the coal consumption
+per day and per indicated horse power per hour.
+
+[Illustration: Fig. 3--OREGON.]
+
+This table, as will be seen, contains some of the most important of
+the Atlantic liners, and also a number of other typical ships, which
+will add a variety to its interest and a value to it. The coefficient,
+which is contained in the thirteenth column of the table, viz.:
+
+        Dis 2/3 × speed³
+    -------------------------
+    I.H.P. × sqrt(entrance.)
+             ---------------
+                     10
+
+generally comes out for ships of similar type more nearly a constant
+in the true sense of the word than the corresponding Admiralty
+constant. As an example, we have the curves of resistance and horse
+power for the City of Rome and the Normandie, a large vessel of 6,000
+tons, which the Barrow Company built for the Compagnie Generale
+Transatlantique, in which the coefficient of fineness and the form of
+the lines pretty closely resemble each other below water; and if we
+take from the curves the corresponding speeds and horse powers, and
+work out the constants by the two systems, we have at 14 knots the
+Admiralty constant for the City of Rome 322.2, and for the Normandie
+304.8; and taking for a modified form of constant, the City of Rome
+gives 253.7 and the Normandie 251.9, which, as will be seen, are much
+closer together. Similarly, at 15 knots the Admiralty constant for the
+City of Rome is 310, and for the Normandie 295.2, while a modified
+constant comes out for the former at 245, and for the latter 244,
+again agreeing almost identically. The same at 16 knots, for the City
+of Rome the Admiralty constant comes out 297.6, and for the Normandie
+282.8, while a modified constant comes out for the two ships 234.4 and
+233.7 respectively, again showing marked agreement. It may be
+mentioned that in these two ships the engines are of a similar type,
+being three-crank tandem engines, and the propellers have in both
+pitch and surface practically the same proportions to the power and
+speed. The value of these modified constants will probably be found to
+increase as the speeds increase up to the limit and beyond that point
+at which wave resistance becomes an important factor.
+
+
+TABLE III
+
+----------------+--------+---------+---------+-------+-------------+
+    Name.       |Length. | Breadth.| Moulded |Midship|Displacement.|
+                |        |         | draught.| area. |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+----------------+--------+---------+---------+-------+-------------+
+                |ft. in. | ft. in. | ft. in. |       |             |
+                |        |         |         |       |             |
+City of Rome    | 542  6 | 52   0  | 21  5½  | 1031  |   11,230    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Normandie       | 459  4 | 49  11  | 19  9¾  |  892  |    7,975    |
+                |        |         |         |       |             |
+Furnessia       | 445  0 | 44   6  | 22  2½  |  893  |    8,578    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Arizona         | 450  0 | 45   1½ | 18  9   |  758  |    6,415    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Orient          | 445  0 | 46   0  | 21  4½  |  904  |    7,770    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Stirling Castle | 420  0 | 50   0  | 22  3   |  990  |    7,600    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Elbe            | 420  0 | 44   9  | 20  0   |  807  |    6,350    |
+                |        |         |         |       |             |
+Pembroke Castle | 400  0 | 42   0  | 17  0   |  648  |    5,130    |
+                |        |         |         |       |             |
+Umbria and      |        |         |         |       |             |
+ Etruria        | 500  0 | 57   0  | 22  6   | 1090  |    9,860    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Aurania         | 470  0 | 57   0  | 20  0   | 1020  |    8,800    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+America         | 441  8 | 51   3  | -----   |  ---  |    6,500    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Oregon          | 501  0 | 54   2  | 23  8   | 1150  |   11,000    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Servia          | 515  0 | 52   0  | 23  3½  | 1046  |   10,960    |
+                |        |         |         |       |             |
+Scotia, P.S.    | 369  0 | 47   6  | 19  9   |  867  |    6,000    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Alaska          | 500  0 | 50   0  | 21  0   |  949  |    9,210    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Aller           | 438  0 | 48   0  | 21  0   |  907  |    7,447    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Ems             | 430  0 | 46  10  | 20  7½  |  877  |    7,030    |
+----------------+--------+---------+---------+-------+-------------+
+
+----------------+----------+---------+-----------+-----------+-----------+
+    Name        |Indicated |  Speed. |   Block   |  Midship  | Prismatic |
+                |   H.P.   |         |coefficient|  section  |  midship  |
+                |          |         |           |coefficient|  section  |
+                |          |         |           |           |coefficient|
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+----------------+----------+---------+-----------+-----------+-----------+
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+City of Rome    | 11,890   |  18.235 |    .649   |    .925   |    .702   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Normandie       |  6,959   |  16.66  |    .614   |    .901   |    .681   |
+                |          |         |           |           |           |
+Furnessia       |  4,045   | ¹14     |    .682   |    .903   |    .755   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Arizona         |  6,300   |  17     |    .589   |    .895   |    .658   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Orient          |  5,433   |  15.538 |    .621   |    .919   |    .676   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Stirling Castle |  8,396   |  18.4   |    .569   |    .889   |    .639   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Elbe            |  5,665   |  16.571 |    .591   |    .901   |    .655   |
+                |          |         |           |           |           |
+Pembroke Castle |  2,435.8 |  13.25  |    .623   |    .623   |    .692   |
+                |          |         |           |           |           |
+Umbria and      |          |         |           |           |           |
+ Etruria        | 14,321   |  20.18  |    .538   |    .896   |    .637   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Aurania         |  8,500   | ¹17.5   |    .575   |    .942   |    .632   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+America         |  -----   | ¹17.8   |    ----   |    ----   |    ----   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Oregon          | 13,300   |  18.3   |    .599   |    .849   |    .67    |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Servia          | 10,300   | ¹16.9   |    .610   |    .862   |    .71    |
+                |          |         |           |           |           |
+Scotia, P.S.    |  4,632   | ¹14.31  |    .605   |    .92    |    .65    |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Alaska          |  -----   |  ----   |    .614   |    .904   |    .679   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Aller           |  7,974   |  17.9   |    .590   |    .899   |    .656   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Ems             |  7,251   |  17.55  |    .593   |    .907   |    .652   |
+----------------+----------+---------+-----------+-----------+-----------+
+
+----------------+------------+-----------------+-----------------+
+    Name.       | D 2/3 × S³ |    D 2/3 × S³   | Kirk's system.  |
+                | ---------- | --------------- |                 |
+                |   I.H.P.   |           _____ +---------+-------+
+                |            |I.H.P. × \/ent.  |Length of|Angle. |
+                |            |         ------- |entrance.|       |
+                |            |            10   |         |       |
+----------------+------------+-----------------+---------+-------+
+                |            |                 |         |       |
+                |            |                 |         |       |
+City of Rome    |    255     |     201.3       |  161.27 | 8° 29'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Normandie       |    265     |     219.5       |  146.41 | 8° 44'|
+                |            |                 |         |       |
+Furnessia       |    284     |     273         |  108.7  |10° 28'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Arizona         |    269.2   |     217         |  153.79 | 7° 30'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Orient          |    270.8   |     225         |  144.17 | 8° 21'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Stirling Castle |    286.8   |     233.7       |  151.3  | 8° 22'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Elbe            |    275.5   |     229         |  144.6  | 7° 56'|
+                |            |                 |         |       |
+Pembroke Castle |    284     |     258         |  122.9  | 8° 49'|
+                |            |                 |         |       |
+Umbria and      |            |                 |         |       |
+ Etruria        |    260     |     191.8       |  184    | 6° 52'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Aurania         |    266     |     204.6       |  170    | 8° 38'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+America         |    ---     |     ---         |   ---   | ----- |
+                |            |                 |         |       |
+                |            |                 |         |       |
+Oregon          |    227.9   |     190         |  164.3  | 9° 39'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Servia          |    231     |     192         |  145.3  |10° 42'|
+                |            |                 |         |       |
+Scotia, P.S.    |    208.9   |     186         |  126.8  |13° 21'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Alaska          |    ---     |     ---         |  160.23 | 8°  2'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Aller           |    277     |     225         |  150.6  | 8° 10'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+                |            |                 |         |       |
+Ems             |    273     |     223         |  149.4  | 8° 40'|
+----------------+------------+-----------------+---------+-------+
+
+----------------+------------+--------------------+----------------+--------+
+    Name.       |   Coal     |      Cylinders     |     Boilers    | Working|
+                |consumption |                    |                |Pressure|
+                |-----+------+-------------+------+--------+-------+        |
+                | Per | Per  |  Diameter   |Stroke|Heating |  Bar  |        |
+                | day |I.H.P.|             |      |surface |surface|        |
+                |     |      |             |      |        |       |        |
+----------------+-----+------+-------------+------+--------+-------+--------+
+                |     |      |    Ins.     | Ins. |        |       | lbs.   |
+                |     |      |/3 @  46    \|      |        |       |        |
+City of Rome    | 185 |  2.2 |\3 @  86    /|  72  | 29,286 |  1398 |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/3 @ 35-7/16\|      |        |       |        |
+Normandie       | 148 |  2   |\3 @ 74-7/8 /|  67  | 21,404 |   756 |   85.2 |
+                |     |      |             |      |        |       |        |
+Furnessia       |  97 |  2.2 |  49-100     |  66  | 10,396 |   440 |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Arizona         | --- |  --- |\2 @  90    /|  66  |  ----  |  ---- |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  60    \|      |        |       |        |
+Orient          | --- |  --- |\2 @  85    /|  60  |  ----  |  ---- |   75   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Stirling Castle | --- |  --- |\2 @  90    /|  66  | 21,161 |   787 |  100   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  60    \|      |        |       |        |
+Elbe            | --- |  --- |\2 @  85    /|  60  |  ----  |  ---- |  ---   |
+                |     |      |             |      |        |       |        |
+Pembroke Castle |  44 |  1.7 | 43 and 86   |  57  |  7,896 |   288 |   99   |
+                |     |      |             |      |        |       |        |
+Umbria and      |     |      |/1 @  71    \|      |        |       |        |
+ Etruria        | 315 |  2.1 |\2 @ 105    /|  72  | 38,817 |  1606 |  110   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  68    \|      |        |       |        |
+Aurania         | 215 |  2.2 |\2 @  91    /|  72  | 23,284 |  1001 |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  63    \|      |        |       |        |
+America         | 185 |  --- |\2 @  91    /|  66  |  ----  |   882 |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  70    \|      |        |       |        |
+Oregon          | 310 |  2.2 |\2 @ 104    /|  72  | 38,047 |  1428 |  110   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  72    \|      |        |       |        |
+Servia          | 205 |   2  |\2 @ 100    /|  78  | 27,483 |  1014 |  ---   |
+                |     |      |             |      |        |       |        |
+Scotia, P.S.    | 168 |  3.4 |             |  --  |  ----  |  ---- |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  68    \|      |        |       |        |
+Alaska          | --- |  --- |\2 @ 100    /|  72  |  ----  |  ---- |  100   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  44    \|      |        |       |        |
+Aller           | --- |  --- ||1 @  70    ||  72  | 22,630 |   799 |  150   |
+                |     |      |\1 @ 100    /|      |        |       |        |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Ems             | --- |  --- |\2 @  86    /|  60  | 19,700 |   780 |  100   |
+----------------+-----+------+-------------+------+--------+-------+--------+
+
+  ¹Mean speed of a voyage across the Atlantic Ocean.
+
+The author next considered the strains to which a ship is exposed, and
+stated that he had before him the calculations for three of the
+largest vessels, two of them of iron and the other of steel; and he
+found, in the case of the iron, the maximum tension on the gunwale
+during the greatest hogging strains likely to be endured at sea would
+not exceed about six tons per square inch, while in the case of the
+steel ship it is only about 6½ tons. These strains are well within the
+limits of safety, and a comparison of the scantlings of these with the
+others justifies the assertion as to their general safety from a
+structural point of view. The sections of these three ships are shown
+in Figs. 1, 2, and 3, with their principal scantlings. It will be seen
+from these sections that the three ships differ materially in their
+mode of construction. In the case of Fig. 1, which represents the City
+of Rome, the largest of the three, it will be seen that the main
+framing of the vessel is entirely transverse, with very heavy keelsons
+in the bottom, and large partial bulkheads or web frames, and the
+outside plating arranged on what is termed the edge to edge principle,
+with a great portion of it double. In the next section, Fig. 2, the
+Servia, which is built of steel, on the other hand, the bottom is
+built on the longitudinal cellular system, the first application, he
+believed, of this system to an Atlantic liner. The plating of the
+Servia is of the usual alternate outer and inner strake system, partly
+double; while the third section, the Oregon, approaches more nearly to
+the ordinary system of framing and plating usually adopted, but it
+will be seen that she was well tied in the bottom by very heavy
+intercostal and plate keelsons, as well as in the top by heavy
+stringers and sheer strakes, with much of her plating doubled, and
+heavy web frames inside. The author next considered the question of
+stability, and went on to deal with the subject of twin screws, and
+stated that the Barrow Shipbuilding Company has done more in the way
+of planning and designing for the adoption of twin screws lately than
+for any other mode of propulsion, and this chiefly for passenger
+steamers. He did not attach much importance to the particular form of
+the blade either in single or twin screws, as he believed so long as
+the disk area, the surface, and pitch were properly adjusted to the
+speed of the vessel, and to enable the engines to use, at the maximum
+speed, just the full quantity of steam that the boilers can make, we
+have got pretty nearly as far as we can get. To fix these dimensions
+of the propeller accurately at the present time, and without further
+knowledge of the action of the screw on the water, was, he thought,
+impossible. All the rules and formulæ are empirical. The best one he
+knew is given in Table IV., due to Mr. Thom, the head of the Barrow
+Company's engineering drawing office, and at present acting manager,
+who has used it for some years in practice. These formulæ are based
+upon the assumption that the area of propeller disk should be
+proportional to the indicated horse power, divided by the cube of the
+speed, and the same with the projected area of the propeller and also
+the surface.
+
+
+TABLE IV.
+
+             _Particulars of Propellers and Constants._
+
+------------------------------+-------+---------+----------+--------------
+                              | Length|         |   Proj.  |  Feet per
+            Ship.             |   of  |  Disk   |   surf.  |   minute.
+                              | ship. |constant.| constant.|Speed of tips.
+------------------------------+-------+---------+----------+--------------
+City of Rome.                 |   542 |   220   |    69    |   4,715
+Normandie                     |   459 |   250   |    66    |   4,099
+Furnessia                     |   445 |   223   |    69    |   3,654
+Eden                          |   300 |   211   |    64    |   3,080
+Yorouba                       |   270 |   213   |    63    |   3,202
+Taygete                       |   260 |   238   |    56    |   3,166
+Kow-shing                     |   250 |   171   |    69    |   3,369
+S.Y. Monarch                  |   152 |   221   |    65    |   4,040
+S.Y. Aries                    |   138 |   179   |    56    |   2,986
+Twin screw Fenella            |   200 |   244   |    64    |   2,890
+Twin screw H.M.S. Fearless[2] |   220 |   277   |    67    |   5,022
+Twin screw H.M.S. Iris        |   --- |   454[6]|   135[6] |    ---
+Twin screw H.M.S. Iris [3]    |   300 |   412   |   221    |    ---
+Twin screw H.M.S. Iris [4]    |   300 |   346   |    99    |   4,961
+Twin screw H.M.S. Iris [5]    |   300 |   439   |    82    |   5,309
+------------------------------+-------+---------+----------+-------------
+
+  [Footnote 2: Estimated with a speed of 17.5 knots and 3,370
+  I.H.P.]
+
+  [Footnote 3: With the first propeller at the estimated speed of
+  17.5 knots and 7,000 I.H.P.]
+
+  [Footnote 4: With four bladed modified Griffith's on actual
+  trial.]
+
+  [Footnote 5: With two bladed modified Griffith's on actual trial.]
+
+  [Footnote 6: Constants obtained from first propeller calculated
+  from a speed of 18.5 knots and 7,500 I.H.P.
+
+                    Area of propeller disk × speed of ship in knots.³
+    Disk constant = --------------------------------------------------
+                                         I.H.P.
+
+    Projected      Projected area of propeller × speed of ships in knots.³
+    area         = ------------------------------------------------------
+    of constants                         I.H.P.
+
+  Expanded area constants may be obtained and used in the same way.]
+
+The discussion which followed was opened by Mr. Holt. He said that if
+they were to have greater speed on the Atlantic, there was one point
+which was not alluded to in the paper, and that was the total
+abolition of cargo on board the great passenger steamers. If vessels
+were built solely for passenger traffic, they would be able to insure
+greater speed by reason of the greater slightness in build and the
+additional space at the command of the designer. The existing Atlantic
+express steamer was far too heavy, and might, if cargo was dispensed
+with, be made with finer lines and more yacht-like. He looked on the
+proposition to fit such vessels with longitudinal bulkheads with great
+fear. If a collision took place--such, for example, as that which sunk
+the Oregon--water would get access to one side only of the ship, and
+it was not at all improbable that if a sea was on, she would turn
+right over. At all events, very serious risk would be involved.
+
+Mr. W.H. White, Chief Constructor to the Admiralty, said the question
+of twin screw propulsion was one of special interest to himself, and
+had been so for many years. In 1878 he dealt with it as fully as he
+then could on the basis of the Admiralty data, and he then ventured to
+say everything in favor of twin screws that Mr. John had said in his
+paper. If greater power than that now used in such a ship as the
+Etruria, for example, were demanded, two screws must be used. Good as
+are the results obtained with the Etruria, it was by no means certain
+that still better might not be had. If she had been fitted with two
+screws instead of one, very great advantage would be gained by the
+greater submergence of the twin screws, as thus racing would be almost
+wholly prevented.
+
+Mr. Calvert urged that more attention should be devoted to studying
+the relative values of different portions of the propeller.
+
+The sitting was then suspended. In the afternoon, as we have already
+stated, the members visited the steamship Germanic on the invitation
+of Messrs. Ismay, Imrie & Co., subsequently proceeding to Messrs. Cope
+Brothers' tobacco works, and thence to the exhibition, where the
+dinner of the Institution took place in the evening.
+
+On Friday morning no paper was read; some official business was
+transacted, and this being done, the discussion on Mr. John's paper
+was resumed.
+
+Mr. Biles remarked that there were many advantages in the use of twin
+screws which had not been sufficiently taken into account. When a ship
+with twin screws was being handled in dock there was greater
+maneuvering power, and therefore less liability for the ship to come
+in contact with the walls, although, if she did so, there would be
+greater probability of damage to the propellers. He thought means
+could be easily devised of protecting the screws when the ship was in
+dock. Another of the incidental advantages connected with twin screws
+was that smaller engines and smaller propellers were required, and
+therefore they might run them at a higher speed. They would also get
+lighter machinery with twin screws, and there would be less liability
+to have bad castings and forgings in the smaller engines, and of
+course the cost would be less.
+
+With respect to the question of the middle line bulkheads, he could
+not quite agree with Mr. John as to the great advantages of them in a
+big passenger steamer. He thought there would be greater difficulty in
+managing a ship so built if she was in danger of sinking. Increased
+subdivision in a longitudinal direction was a very desirable thing,
+and almost necessary for a condition of immunity from sinking. In
+future Atlantic steamers longitudinal bulkheads should be placed not
+in the middle line, but nearer the sides of the ships, and they should
+recognize the fact that they had engines and boilers in different
+compartments, and make arrangements whereby the ship would still
+float, although the doors in these compartments were kept open. The
+proper way to arrive at that was to have a ship with great beam, and
+to have two longitudinal bulkheads at considerable distances from the
+sides of the ship, subdivided as completely as possible, both under
+and above water, so that, even supposing they got water into the space
+between one bulkhead and the side of the ship, they would have
+sufficient buoyancy in the other parts of the ship to keep her afloat.
+Broad ships must necessarily mean deep ships, in order to have comfort
+at sea. They were limited in length, and first came the question how
+many passengers they wanted to carry. The experience of a ship like
+the America--which was only 400 ft. in length--showed it was not
+necessary to go to great length to have great speed. A ship of 400 ft.
+to 430 ft. in length, 65 ft. of beam, and with a depth of 45 ft.,
+would be a ship of proper dimensions for the Atlantic trade, and he
+believed it quite possible to build a vessel of special construction
+of about 7,000 tons gross register which should steam with less
+consumption of coal than the Umbria and Etruria at a rate of 22 knots,
+crossing the Atlantic from Liverpool to New York in six days. He
+thought that was likely to be the vessel of the future, and that it
+would be quite as commercially successful as the Umbria or Etruria.
+
+Mr. J. Campbell remarked that at present the great American liners had
+only the ordinary compound engines, and he thought that, instead of
+converting them to triple expansion, they should take a step further
+at once, and adopt quadruple expansion engines. This class of engines
+was being very successfully built in various parts of the country. He
+should recommend the adoption of a three-crank six-cylinder engine.
+
+Mr. Hamilton did not think it had been demonstrated that greater
+efficiency had been got out of twin screws than out of single screws;
+but there was no doubt they would tend to additional safety.
+
+Mr. Martell said that when they had got satisfactory data, twin screws
+would be adopted for ships requiring great speed; but they had not got
+that data at present.
+
+Admiral Sir John Hay, referring to twin screws as applying to
+sea-going steamers which might be employed for imperial defense, said
+it was quite certain that the defense of their extended commerce
+would always require to be assisted by ships such as the Oregon and
+other magnificent vessels which had been used for that purpose on a
+recent occasion. He believed that for war purposes the twin screw was
+recognized by all naval men as having very many advantages. If that
+were so, it was quite evident that it would be a great advantage,
+under such conditions as occurred at the loss of the Oregon, if the
+compartments could be made completely water-tight; and the twin screw,
+with the separation of the ship longitudinally, gave them the very
+greatest possible protection. They could not trust to bulkheads that
+were only closed occasionally by doors. What was required for war
+purposes was the entire and complete isolation of different parts of
+the ship, having always practically closed communications between
+them.
+
+Mr. John then replied on the general discussion. He was pleased to
+find that they had faith in the future of the twin screw and of
+subdivision. The public had a right to demand greater safety than they
+at present had on the Atlantic, or could have with a single screw.
+
+       *       *       *       *       *
+
+
+
+
+EXAMINATION QUESTIONS IN GENERAL CONSTRUCTION.
+
+
+The following is a copy of the last examination paper given to
+candidates who are desirous of employment in the constructive
+departments of the municipality of New York:
+
+N.B.--In case candidate does not remember formula or method of solving
+any problem submitted to him, let him name any work upon the subject
+where such formula or method may be found.
+
+1. What is civil engineering?
+
+2. Have you ever pursued a course of study in any educational
+institution, or with any civil engineer, which would fit you for the
+position of assistant engineer? If so, state when and with whom; state
+also, in detail, what experience you have had.
+
+3. Have you ever had responsible charge of any public work? If so,
+state particulars.
+
+4. Solve the following according to the algebraic signs:
+
+      --------------------------------------
+     / (6-2/7 - 4-3/9) × 8-7/16
+    /  ------------------------ × 67873.367,     and show your work.
+  \/            4-4/12
+
+
+5. The population of a certain town in 1880 was 7,095; it having
+increased 25 per cent. in ten years, what was it in 1870? Show your
+work.
+
+6. How many feet, board measure, in the flooring of a room 20 feet by
+30 feet and 2½ inches thick?
+
+7. Find value of x and y in the following equations:
+
+  2 x + 3 y = 33
+  4 x - y = 17.
+
+8. Find value of x in equation x² - x - 40 = 170.
+
+9. Find value of x in equation
+
+          --------
+   a     / a² - x²   x
+   - +  /  ------- = -
+   b  \/      x²     b
+
+10. Explain the meaning of the expression a½ × b¾.
+
+11. What is a logarithm?
+
+12. What is the base of the common system?
+
+13. In making what calculations are logarithms useful?
+
+14. How do you find the logarithm of a number in a table of
+logarithms?
+
+15. What are similar triangles?
+
+16. How are similar triangles proportioned to each other?
+
+17. The sides of a polygon being prolonged, what is the sum of all the
+exterior angles equal to?
+
+18. How do you pass the circumference of a circle through three given
+points not in the same straight line?
+
+19. How do you describe a square in a circle?
+
+[Illustration]
+
+20. In the triangle, b being a right angle, what proportion does d b
+bear to a d and d c?
+
+21. How do you inscribe a regular hexagon in a circle?
+
+22. What proportion do circumference and areas of circles bear to
+their radii?
+
+23. How do you find the area of a regular polygon?
+
+24. Of an irregular polygon?
+
+25. Of a circle?
+
+26. How do you find the solid contents of a cylinder?
+
+27. Of a wedge?
+
+28. Of a pyramid?
+
+29. Find the contents of the wedge, base 20 feet by 30 feet, height 10
+feet, edge 15 feet.
+
+30. State the prismoidal formula; would you use it in calculating
+earthwork?
+
+31. Is a simple question in calculating areas.--Ed. _Eng. News_.
+
+32. How many and what parts of a plane triangle must be given to find
+the rest?
+
+33. Define the terms sine, co-sine, tangent, and co-tangent.
+
+34. What are natural sines, co-sines, etc.?
+
+35. What is a table of logarithmic sines, co-sines, etc.?
+
+30. Two sides and two angles of a plane triangle being given, how do
+you find the other parts?
+
+37. When two sides of a plane triangle and their included angles are
+given, how do you find the other parts?
+
+38. In the right-angled triangle, A B H express algebraically the
+value of the sine, co-sine, tangent, and co-tangent of angle A in
+terms of a, b, and h, they being the altitude, base, and hypothenuse
+of the triangle.
+
+39. What is the law of gravitation?
+
+40. Do you understand that there is any difference in the meaning of
+the terms gravitation and gravity?
+
+41. What is the law of falling bodies?
+
+42. Express algebraically this law, taking v = velocity of falling
+body; g = acceleration of gravity; and h = height.
+
+43. What is the center of gravity of a body?
+
+44. How is it found?
+
+45. Where is the center of gravity of a homogeneous body whose sides
+are all rectangles?
+
+46. What is the specific gravity of a body?
+
+47. What is the standard for solids and liquids?
+
+48. What for gases?
+
+49. What laws govern the pressure of liquids at rest?
+
+50. How do you find the number of gallons of water to the cubic foot?
+
+51. What is the weight of a gallon of water?
+
+52. What is the pressure per square inch on the side of a vessel at
+the depth of 10 feet below the surface of the water?
+
+53. What will be the theoretical volume of discharge per second from a
+reservoir through a pipe 1 foot in diameter, discharging at a depth of
+100 feet below the surface of the water?
+
+54. How many gallons of water will be discharged through a pipe 1 foot
+in diameter, 328 feet long, head 13½ feet, coefficient of flow =
+0.007?
+
+55. State how many men are needed to make up a full party for a survey
+of a preliminary line or location of a public work, such as a railroad
+or aqueduct.
+
+56. State also their several duties.
+
+57. For what purpose is the magnetic needle used in surveying land?
+
+58. What is a traverse table and for what used?
+
+59. How do you set out a circular curved line upon the ground?
+
+60. If an obstacle occurs to alignment, state how you would overcome
+it upon straight lines, also upon curves.
+
+61. The radius of a curve being given, and angle of intersection of
+the two tangents, how do you find the length of the tangent from their
+intersection to the beginning of the curve?
+
+62. Describe an engineer's transit, and name its adjustments.
+
+63. Describe a Y level, and name its adjustments.
+
+64. How many kinds of leveling rods do you know of?
+
+65. State how they are graduated, and how they can be read to the
+1/1000 of a foot.
+
+66. Show a form of field-book for transit notes used when "running"
+curves, and place thereon notes of a 5 deg. curve for 1,000, with two
+intermediate "set-ups."
+
+67. Show a form of level-book, and place therein sufficient figures to
+show your method.
+
+68. What are cross-sections?
+
+69. How do you set slope stakes for excavation and embankment?
+
+70. What is a grade line?
+
+71. What proportion of the breaking weight of a beam would you
+consider a safe load?
+
+72. With the load uniformly distributed, what fractional part of the
+whole weight may be considered, in all calculations, as being carried
+at the center?
+
+73. Suppose a beam supported at both ends, and take w = weight, l =
+length of beam, b = breadth, d = depth, s = breaking weight. Express
+algebraically the value of s in terms of the other quantities.
+
+74. Sectional area being 36 square inches, which would be the stronger
+section, 6 by 6 or 4 by 9?
+
+75. Make a design for a pair of rafters, connected by a tie-beam, for
+a roof 30 feet span, showing the dimensions of the several parts and
+the manner of connecting them. State in detail your method of
+obtaining the several dimensions.
+
+76. How do you apply the principle of the parallelogram of forces in
+determining the strain on the various members of a structure?
+Illustrate graphically.
+
+77. What should be the thickness at the top and base of a retaining
+wall 15 feet high, built to retain ordinary earth? Show your method of
+obtaining the required dimensions, also a sketch of the wall, showing
+how it should be founded.
+
+78. A reservoir is to be built, depth of water 10 feet. If the walls
+are built of masonry, find the thickness of the same, and state how
+they should be built. Show your work.
+
+79. What is an arch, of how many forms, and of what may it be
+constructed?
+
+80. Can you state how you would find the thickness of an arch of
+stone, span and rise being given?
+
+81. Define the intrados and extrados of an arch.
+
+82. Where should the line of resistance to pressure be found in an
+arch in order to retain its stability?
+
+83. Can you find the thickness of the abutments, the rise and span of
+the arch being given?
+
+84. In a semicircular arch, where is the horizontal thrust greatest
+and where least?
+
+85. Name the common kinds of stone used in building.
+
+86. Define the terms "quarry-faced," "rough-pointed," "fine-axed,"
+"bush-hammered," as applied to the dressing of stone.
+
+87. Describe "rubble" masonry, "ashlar" masonry, and "broken ashlar"
+masonry.
+
+88. What are "headers" and "stretchers"?
+
+89. What should be the proportion of "headers" to "stretchers"?
+
+90. How would you prepare the foundation for a heavy wall, and how
+deep should it be excavated?
+
+91. How are walls founded on soft or yielding materials?
+
+92. Describe a good quality of bricks, and state how you would know a
+good brick from a poor one.
+
+93. In how many ways is brickwork "bonded" to make good work in heavy
+walls?
+
+94. What is hydraulic cement, and how many kinds do you know of?
+
+95. Which do you consider the better quality, Rosendale or Portland,
+and why?
+
+96. What is mortar composed of, and how mixed?
+
+97. What kind of sand should be used, and how do you test its quality?
+
+98. What is the meaning of the term "setting" as applied to cement?
+
+99. How would you test cement?
+
+100. What is concrete, of what composed, and in what proportion should
+its ingredients be mixed?
+
+101. Name the common kinds of wood used in building.
+
+102. What kind of timber resists decay longest under ground?
+
+103. How may timber be preserved from decay?
+
+104. What do you understand by limit of elasticity as applied to a
+beam under strain or pressure? What is meant by the neutral axis of a
+beam?
+
+105. What is the tensile strength of a good quality of wrought iron
+per square inch?
+
+106. For what parts of a structure may cast and wrought iron be used
+in reference to tension and compression?
+
+107. Make a sketch of the form of cast-iron beam best adapted to
+resist a transverse strain.
+
+       *       *       *       *       *
+
+
+
+
+CELEBRATION OF THE FIVE HUNDREDTH ANNIVERSARY OF THE UNIVERSITY OF
+HEIDELBERG, AUGUST, 1886.
+
+
+The wave of pleasure and enjoyment which flooded everything has
+passed. Heidelberg, usually so quiet, assumed the role of a city of
+the world, and all was bustle and excitement in the streets, which
+were hung with flags and other decorations. The trains constantly
+brought new accessions to the crowd, and gayety and mirth reigned
+supreme.
+
+The dedication of the renovated _Aula_ of the University served as a
+prelude to the festivities of the week. On this occasion a splendid
+flag, embroidered by order of the wives of the faculty of the Academy,
+an equally costly cover for the scepter, and a silver inkstand were
+added to the treasures of the University. Conspicuous among the
+numerous presents received were a richly carved set of furniture--the
+gift of former students from Switzerland--and all the publications of
+certain book dealers.
+
+On the afternoon of August 2, the Grand Duke and Duchess arrived in
+Heidelberg, where they were received with much enthusiasm. They
+remained at the modest palace during the time of the jubilee, and
+whenever they appeared they were greeted with expressions of
+patriotism and love. On the evening of the 2d, the _Oberburgermeister_,
+Dr. Wilckens, extended a hearty welcome to the guests who had gathered
+in the over crowded hall. Vincenz Lachner conducted the musical part of
+the entertainment, which was charming. The German Crown Prince arrived
+early on the 3d, so as to accompany his royal cousins to the service in
+the beautifully decorated _Heiliggeistkirche_, on which occasion Prof.
+Bassermann spoke with great effect. At 11 o'clock, the Court appeared in
+the _Aula_, where the Grand Duke presided, in virtue of his office of
+"Rector Magnificentissimus." His address was followed by those of the
+Crown Prince; the _Prorector Geheimrath_, Dr. Bekker; Edward Zeller, of
+Berlin; Jules Zeller, of Paris; and others. In the evening the citizens
+and strangers were attracted to the _Jettenbühel_ by the festival at the
+castle; from 7:30 until 10 o'clock the nobility held court in the
+_Bandhause_. The scene was like fairyland, all the outlines of the
+castle were marked by thousands of small lights, and the court was
+lighted by great candelabra. In the ever-increasing crowd it was
+difficult to find a place and to obtain refreshments, which were given
+out in immense quantities by the State.
+
+On the morning of the 4th the people thronged again to the
+_Heiliggeistkirche_ to listen to the address of the _Geheimrath_, Dr.
+Kuno Fischer, on the fate of the Palatinate and Heidelberg, which was
+preceded and followed by music. After this the participants in the
+festival were brought together by a dinner in the Museum Hall, and
+seldom have speeches so inspired an audience as did those of the Grand
+Duke and the Crown Prince. Never has Heidelberg seen such a
+torch-light procession as that formed by the students in honor of
+their Rector; 3,000 torches lighted him to the City Hall. He thanked
+them, and proposed cheers for the Crown Prince.
+
+On the morning of the 5th there was the presentation of degrees. In
+the afternoon a special train carried four hundred people to
+Karlsruhe, where the royal party held a great reception. The capital
+was decorated with flags, the city parks were lighted with Bengal
+lights, there was music, and a song by the patriotic bard Vierordt was
+sung.
+
+All the splendor and interest shrank into insignificance before the
+grand historical procession on the morning of the 6th, which made a
+lasting impression on the minds of all. The throng of 100,000 people
+watched quietly while the whole history of the Palatinate passed in
+review before them. The procession illustrated this history much
+better than it could have been told by any professor or any book.
+There was not a vacant space to be found, extra trains having brought
+more spectators, and yet everything passed off quietly and without
+accident. In the evening there was a heavy shower, which freshened
+everything, leaving no ill effects to be seen the next morning, which
+was more than could be said of many of those who attended the imposing
+_Commerse_ of the Heidelberg students. As a former student, the Grand
+Duke appeared among the 6,000 visitors at the _Commerse_, where he
+presided and spoke enthusiastically of the Emperor. Other speeches
+followed, until the conversation became so animated that even Von
+Treitschke, who was received with an ovation, could not be heard. At
+midnight the court retired and the _Fidelitas_ succeeded to their
+rights.
+
+On the 7th the time was spent in excursions and carousing until the
+illumination of the castle began. I never saw an illumination of the
+ruins which could compare in beauty with that of the 7th. The night
+was favorable for fireworks, until finally they were rivaled by the
+moon, numerous boats trimmed with colored lanterns passed along the
+river, there were fire-wheels on the bridge, water fireworks on the
+river, and the quiet was disturbed alternately by the rockets and
+music, and when the names of the Grand Duke and Duchess, crowned with
+brilliant fire, appeared over the water, there was an involuntary
+outburst of enthusiasm. If the old Elector and Electoress could have
+been present at the closing entertainment of the jubilee, on the
+evening of the 8th, they would have rejoiced to see the new life
+brought to the ruins by their successor.--_Illustrirte Zeitung._
+
+       *       *       *       *       *
+
+
+
+
+MANUFACTURE OF LEATHER IN RUSSIA.
+
+
+From this extensive paper it appears that the matters chiefly used in
+tanning are the bark of the oak, containing from 6.04 to 4.37 per
+cent. of tannin according to the season, that of willows, of the elm,
+and the birch. The leaves of the arbutus, employed in the governments
+of Kasan, Viatka, and Perm, contain about 16 per cent. of tannin,
+while the root of wild sorrel (_Rumex acetosella_) contains 12 per
+cent. For removing the hair from hides, a lye made from wood ashes is
+still employed. The softening of the leather is effected by means of
+the excrement of dogs, which acts on the leather by means of the
+biliary acid present, which forms with soda a kind of soap. After
+tanning, white Russia leather is coated with a mixture of tar and seal
+oil. Black Russia leather is dyed with alum, extract of sanders, and
+ferrous sulphate. Horse hides are tanned to a great extent for sole
+leather.--_M. Ryloff._
+
+       *       *       *       *       *
+
+
+
+
+IMPURITIES IN PHOTOGRAPHIC CHEMICALS, AND TESTS FOR SAME.
+
+
+[Table referred to in a paper read before the Birmingham Photographic
+Society by G.M. JONES, M.P.S.]
+
+  ------------------+---------------------+----------------------------------
+  SUBSTANCE         |     IMPURITIES      |             TESTS.
+                    |  POSSIBLY PRESENT.  |
+  ------------------+---------------------+----------------------------------
+  Ammonia,          | Carbonic acid       | Renders lime-water milky.
+  NH_{3}            |                     |
+  Molec. Wt. 17     | Dissolved solid     | Residue left on evaporation.
+                    | matter              |
+                    |                     |
+                    | Chlorides           | After acidulating with nitric acid,
+                    |                     | it gives a precipitate with silver
+                    |                     | nitrate, which after washing is
+                    |                     | readily soluble in ammonia and
+                    |                     | reprecipitated by nitric acid.
+                    |                     |
+                    | Sulphates           | After acidulating with nitric acid,
+                    |                     | it gives a precipitate with
+                    |                     | barium nitrate.
+                    |                     |
+                    | Lime                | A white precipitate with oxalate
+                    |                     | of ammonium.
+                    |                     |
+                    | Lead is often       | Black precipitate with sulphureted
+                    | present, derived    | hydrogen.
+                    | from the action     |
+                    | upon flint glass    |
+                    | bottles             |
+                    |                     |
+  Nitric acid.      | Traces of           | After dilution it gives a
+  H, NO_{3}         | sulphuric acid      | precipitate with barium nitrate.
+  Molec. Wt. 63     |                     |
+                    | Chlorides           | After dilution it gives a
+                    |                     | precipitate with silver nitrate.
+                    |                     |
+                    | Peroxide of nitrogen| The acid is yellow.
+                    |                     |
+                    | Iodine may be       | After dilution and cooling it gives
+                    | present if the acid | a blue color with starch, paste,
+                    | be prepared from    | or mucilage.
+                    | sodium nitrate      |
+                    |                     |
+  Hydrochloric      | Free chlorine       | Liberates iodine from solution
+  acid, HCl         |                     | of potassium iodide. See also
+  Molec. Wt. 36.5   |                     | "Chlorides," nitric acid.
+                    |                     |
+                    | Sulphuric acid      | As above for nitric acid.
+                    |                     |
+                    | Perchloride of iron | Yellow color. Brown precipitate
+                    |                     | with ammonia added till it
+                    |                     | smells slightly.
+                    |                     |
+  Sulphuric acid,   | Bisulphate of       | Residue on evaporation.
+  H_{2}SO_{4}       | potassium           |
+  Molec. Wt. 98     |                     |
+                    | Sulphate of lead    | Milkiness on dilution. May be
+                    |                     | completely freed from lead by
+                    |                     | diluting with three or four times
+                    |                     | as much water, and allowing
+                    |                     | to settle.
+                    |                     |
+  Acetic acid       | Water               | Does not solidify when cooled
+  (glacial),        |                     | to 17° C. (53º F.)
+  H C_{2}H_{3}O_{2} |                     |
+  Molec. Wt. 60     | Sulphurous and      | White precipitates with silver
+                    | hydrochloric        | nitrate.
+                    | acids               |
+                    |                     |
+                    | Aldehyde, or        | Blackens in the light after adding
+                    | volatile tarry      | silver nitrate.
+                    | matter              |
+                    |                     |
+                    | Organic sulphuric   | Smell of garlic.
+                    | acid                |
+                    |                     |
+  Citric acid,      | Tartaric acid       | Strong solution of potassium.
+  H_{3}C_{6}        |                     | Acetate added to a strong solution
+  H_{5}O_{7}H_{2}O  |                     | of the acid will deposit white
+  Molec. Wt. 210    |                     | crystalline bitartrate.
+                    |                     |
+  Pyrogallic acid   | Metagallic acid     | Black residue, insoluble in water.
+  (C_{6}H_{3})HO_{3}|                     |
+  Molec. Wt. 126    |                     |
+                    |                     |
+  Silver nitrate,   | Free nitric acid    | Reddens litmus paper. (Neutral
+  AgNO_{3}          |                     | silver nitrate does not
+  Molec. Wt. 170    |                     | affect litmus.)
+                    |                     |
+  Potassium         | Chlorides and       | Same as for ammonia.
+  carbonate         | sulphates           |
+  K_{2}CO_{3}       |                     |
+  Molec. Wt. 138    |                     |
+                    |                     |
+  Potassium         | Potassium  carbonate| A strong solution is alkaline to
+  iodide, KI        |                     | test paper.
+  Molec. Wt. 166    |                     |
+                    | Sulphates and       | Same as for ammonia.
+                    | chlorides           |
+                    |                     |
+                    | Potassium iodate    | A pretty strong solution becomes
+                    |                     | yellow from liberation of iodine
+                    |                     | on addition of dilute sulphuric
+                    |                     | acid or, better, a strong solution
+                    |                     | of citric acid.
+                    |                     |
+  Potassium         | Similar to          | See potassium iodide.
+  bromide, KBr      | potassium iodide    |
+  Molec. Wt. 119    |                     |
+                    |                     |
+  Sodium carbonate, | Chlorides and       | Same as for ammonia.
+  Na_{2}CO_{3}      | sulphates           |
+  Molec. Wt. 106    |                     |
+                    |                     |
+  Sodium chloride,  | Chloride of calcium | Oxalate of ammonium (after
+  NaCl              | Chloride of         | addition of a little acetic acid)
+  Molec. Wt. 58.5   | magnesium           | gives a milkiness, or precipitate,
+                    |                     | indicating calcium; filter this
+                    |                     | out and add ammonia, chloride of
+                    |                     | ammonium, and phosphate of sodium
+                    |                     | (clear solutions). A precipitate
+                    |                     | indicates magnesium. Both the above
+                    |                     | cause dampness in wet weather.
+                    |                     |
+                    | Sodium sulphate     | As for "sulphates" in ammonia.
+                    |                     |
+  Potassium         | Potassium carbonate | Effervescence with dilute acids,
+  cyanide, KCN      | nearly always       | giving off a gas carbonic
+  Molec. Wt. 65,    | present             | anhydride, which renders
+  and hydrate, KHO  |                     | lime-water turbid.
+  Molec. Wt. 56     |                     |
+  Kaolin            | Chalk               | Effervescence with dilute acids.
+                    |                     |
+  Water,            | Sulphates and       | Same as for ammonia.
+  H_{2}O            | chlorides           |
+  Molec. Wt. 18     |                     |
+                    | Calcium carbonate,  | Deposited by boiling. Test as
+                    | temporary hardness  | for calcium chloride. See
+                    |                     | sodium chloride.
+                    |                     |
+                    | Ammonia, almost     | Brown coloration, or
+                    | always present in   | precipitate with Nessler's
+                    | distilled and rain  | reagent.
+                    | water               |
+                    |                     |
+  Gelatine          | Alum                | Ash, sometimes as much as ten
+                    |                     | per cent.
+                    |                     |
+                    | Fatty matter        | Separated by precipitation with
+                    |                     | alcohol. Dissolved out by ether
+                    |                     | or benzine, and left as a residue
+                    |                     | on evaporation of the solvent.
+                    |                     |
+                    |                     |
+  Ammonium bromide  | Potassium bro-      | Leaves a residue when heated.
+  (NH_{4})Br        | mide or other       |
+  Molec. Wt. 98     | non-volatile        |
+                    | bodies              |
+                    |                     |
+                    | Ammonium chloride   | Same as for chlorides in
+                    |                     | ammonia.
+                    |                     |
+  Pyrogallic acid   | Powdered glass      | Left behind on solution.
+                    |                     |
+  Potassium iodide  | Potassium bromide   | The crystals of bromide are
+                    |                     | usually more transparent than
+                    |                     | those of iodide, but no reliance
+                    |                     | can be placed on this.
+                    |                     |
+  Silver nitrate    | Potassium nitrate,  | Will not yield the full quantity
+                    | sometimes present   | of chloride on precipitation
+                    | in the fused        | with HCl. Gives a purple color to
+                    | sticks--not in      | flame.
+                    | the crystals        |
+                    |                     |
+  Sulphuric acid    | When vended as pure,| No easy test can be given, as the
+                    | it invariably       | substances are so numerous some of
+                    | contains a trace of | them volatile, and most require
+                    | iron. Common acid is| separation from the acid before
+                    | also liable to      | detection.
+                    | contain arsenic,    |
+                    | selenium, thalium,  |
+                    | and many other      |
+                    | substances.         |
+                    |                     |
+                    | Organic matter, as  | Gives a brown color to the acid.
+                    | a piece of straw    |
+                    | in a carboy of acid |
+                    |                     |
+  Hydrochloric acid | Arsenic             | Marsh's test.
+                    |                     |
+                    | Some yellow samples | Reinsh's test; a small piece of
+                    | contain no iron,    | copper foil becomes coated
+                    | but an organic salt,| on boiling in dilute acid.
+                    | and give an alkaline|
+                    | ash on ignition of  |
+                    | the residue after   |
+                    | evaporation         |
+                    |                     |
+  Calcium chloride  | Calcium hydrate     | The clear filtered solution made
+                    |                     | with distilled water is alkaline
+                    |                     | to test paper, and gives a
+                    |                     | precipitate on breathing into it
+                    |                     | through a tube.
+                    |                     |
+  Pure (?) chemicals| Broken glass, bits  | These impurities either float or
+   generally        | of straw, wood,     | sink on solution, and may easily
+                    | paper, etc.         | be seen.
+  -------------------------------------------------------------------------
+
+G.M. JONES, M.P.S.
+
+       *       *       *       *       *
+
+
+
+
+THE CATASTROPHE AT CHANCELADE.
+
+
+The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885,
+under circumstances that are still fresh in the minds of all, have
+gained a celebrity that renders it unnecessary for us to revert to the
+details of the catastrophe. It will suffice to recall the fact that
+after the accident a private committee was formed for the purpose of
+making an attempt to save the five victims who had been surprised in
+the drifts, and who happened to be in the bottom levels.
+
+[Illustration: FIG. 1.--PHOTOGRAPHIC EXPLORING APPARATUS.]
+
+The Lippmann establishment at once offered to make a boring by means
+of which it would be possible to communicate with the galleries in
+which the men were imprisoned, but, despite the most active efforts,
+success was found impossible. In order to satisfy public opinion, the
+committee resolved to bore a well 12 inches in diameter to a depth of
+23 feet, that should permit of reaching the gallery; but this did not
+render the latter accessible. How was it to be seen what had occurred,
+how was it to be made certain that the men were dead, and that all
+hope of rescue must be abandoned? To Mr. Langlois, a Parisian
+photographer, was confided an order to construct a special apparatus
+which might be let down to the bottom of the well by a cord, and
+which, being capable of operating from a distance, should furnish the
+required information through sensitized plates. As may be seen, this
+operation presented peculiar difficulties, although Mr. Langlois was
+enabled to overcome these with much skill.
+
+The photographic apparatus that the ingenious operator constructed was
+contained in a metallic case that could be let down into the bore
+hole. The upper and lower parts of the contrivance were provided with
+incandescent lamps, that could be lighted or extinguished from a
+distance, by means of conductors. The photographic apparatus, properly
+so called, formed of an objective and camera with its sensitized
+plate, was inclosed in a cylinder 3½ inches in diameter. By means of a
+cord drawn at the mouth of the well, the apparatus could be made to
+issue from its vertical sheath, and to pivot around its axis so as
+take views in different directions (Fig. 1).
+
+The entire affair was suspended by twelve-foot iron rods, connected
+with each other end for end.
+
+In using the apparatus, the operating was done in a shanty, which
+served as a dark room. The device was let down into the bore well
+until it touched bottom. At this moment a cord was pulled so as to
+raise the camera, and then a few moments were allowed to elapse in
+order that the apparatus might become immovable. As the objective was
+all the time in the dark, it had neither cap nor shutter, but was
+unmasked from the beginning of the operation.
+
+In order to form an impression on the plate, it was only necessary to
+give light; this being easily done by passing an electric current by
+means of a commutator, so as to light the incandescent lamps. At the
+end of the exposure, the lamps were extinguished and the entire
+apparatus was immersed in darkness. The mean time of exposure was from
+four to five minutes. The apparatus was then hauled up, and the
+negative developed.
+
+The experiments could be renewed as often as necessary, and the
+apparatus be pointed in all directions by turning it a certain number
+of degrees by means of a lever attached to the upper rod. In this way
+were obtained various views of the inaccessible gallery in different
+planes.
+
+[Illustration: FIGS. 2 AND 3.--REPRODUCTION OF PHOTOGRAPHS TAKEN IN
+THE INACCESSIBLE GALLERIES.]
+
+We reproduce herewith two of Mr. Langlois' most interesting
+photographs. One of these shows the head of the corpse of a young
+miner whose face stands out in relief against the side of the gallery
+(Fig. 2) the other shows a wheel and a lot of debris heaped up
+pell-mell (Fig. 3).
+
+The series of proofs obtained from small negatives, two inches square,
+gave the completest sort of information in regard to the aspect of the
+subterranean gallery.
+
+The exact place where the boring had been done and the entire and
+broken pillars were recognized, as was also the presence of two
+corpses, thus showing that it was indeed here that it would have been
+necessary to act in order to render aid to the unfortunates.
+
+[Illustration: FIG. 4.--FAULT THAT CAUSED THE ACCIDENT.]
+
+In Fig. 4 is shown the appearance of the great fault that caused the
+accident at Chancelade. It seems to us that this method of
+photographing inaccessible subterranean galleries ought to receive
+numerous applications in the future.--_La Nature._
+
+       *       *       *       *       *
+
+
+
+
+SOMZEE'S NEW GAS-BURNERS.
+
+
+With the object of effecting a very intimate mixture of gas and air,
+and of causing this mixture to reach the point of ignition at as high
+a temperature as possible, M. Leon Somzee, of Brussels, has designed
+several new forms of gas burner, which we now proceed to describe and
+illustrate, from particulars and by drawings kindly supplied by an
+esteemed Brussels correspondent.
+
+The high-power burner shown in Fig. 1 effects perfect combustion of
+the heated mixture of air and gas, which is introduced by the draught
+determined by the arrangement. What chiefly distinguishes this burner
+from others of its class is the fact that it is perfectly suited to
+domestic lighting--that is to say, it may be arranged for a
+comparatively small consumption of gas, while giving an increase of
+250 per cent. of light.
+
+[Illustration: FIG. 1. and FIG. 2. INCANDESCENT AND HIGH-POWER
+BURNERS.]
+
+The burner proper is a cage or basket of specially prepared magnesia,
+which yields a warmer tone of light than any obtained hitherto, while
+not requiring so high a temperature before combustion. The cap, made
+of a fire-resisting substance, fits on to a tubular arrangement, R,
+fixed in the upper portion of the body of the burner. The latter is
+supplied by air entering at the cone, O, which terminates the inner
+chamber, K, of the heater, and also by that drawn in by the rising
+column of gas, passing before the orifices, D, which may be regulated
+at will. The small burner, I, which is kept constantly alight, heats
+the central compartment, K, the sides of which transmit heat to the
+gas circulating in the annular casing, L, of the compartment. The
+heated gas passes, by the passage, AA¹, into the space, C, where it
+becomes intimately mixed with the air entering at OP, and also with
+the outer air arriving by the lateral apertures, D.
+
+The _vis viva_ of the jet is diffused through this mixture, which thus
+becomes very intimate, when it penetrates into the tubular
+arrangement, R; combustion now taking place at the top, while the
+refractory cap emits a bright orange light of great steadiness. As it
+is not the flow of gas which determines the entrance of the outer air,
+the former may be used at any pressure--an advantageous arrangement in
+all respects.
+
+When the small burner, I, in the lower chamber is lighted, the
+products of combustion issue by the orifice, O, of the compartment,
+terminating in a needle like that of the steam injector; and the jet
+draws along the air entering the apertures, PP, above the cone. The
+gas from the pipe, arriving from the annular space, L, fills the two
+lateral pockets shown in dotted lines, and passes through the
+orifices, AA¹, which communicate with the upper chamber of the
+burner. The manner in which it is conveyed thence to the tubular
+arrangement has already been described.
+
+Fig. 2 shows a more simple method of carrying out the same principle,
+and of effecting a considerable saving in gas for a given intensity of
+light. In this form, a wick, T, impregnated with an alkaline earthy
+solution, a few seconds after lighting, affords a focus of white light
+remarkable for its steadiness and brilliancy. A draught of air is
+created by a jet of gas issuing from the hollow needle, B, and passing
+through the vessel, D, which is provided with orifices, O, for the
+entrance of air. The air and gas pass from D into C, whence (after
+their intimate mixture is effected) they pass into the tubular
+arrangement, F, at the top of which combustion takes place.
+
+To regulate the proportions in which the air and gas should mingle, in
+order that the combination should be as intimate as possible, the air
+inlet is made variable by a perforated collar, which permits of the
+orifices, O, being more or less covered. The other proportions of the
+burner--that is to say, the relative capacity of the two compartments
+and the length of the hollow needle--are determined by the sectional
+area of the supply-pipe for the gas, which is admitted under moderate
+pressure. Instead of a wire-gauze cap, impregnated with a solution of
+metals or of salts, two fine platinum wires may be used--one bent into
+the form of a semicircle of about an inch radius, and the other (of
+slightly larger diameter) rolled spirally round the former. When both
+ends of the two wires are connected with the upper portion of the
+tubular arrangement (which in this case is flattened), and the gas is
+ignited at the burner, the metallic arc becomes red hot, and then
+brightly incandescent, emitting a light, less brilliant indeed than
+with magnesia, but of remarkable steadiness.
+
+In this case the production of light is chiefly due to the fact that
+calorific condensation, caused by the use of the helicoidal coil
+surrounding the curved wire, prevents loss of heat in this conductor.
+In these forms of high-power burner, in which the gas is used directly
+for the production of light, the difficulty generally encountered of
+heating the air (present in a larger volume than the gas) has been
+successfully overcome.
+
+Fig. 3 shows the straight and outspread flame burner with a special
+heater. In this arrangement the gas and air are heated before
+combustion, in the compartment, G, directly exposed to the action of a
+small Bunsen burner, R, which is placed (in an opaque glass) in the
+middle of a lyre-shaped figure formed by the two gas-pipes, AA. The
+burner proper consists of two fine annular passages meeting above, and
+emitting a thin annular sheet of gas over the guide, T, made of a
+white refractory substance placed between the two annular jets. The
+object of this guide is to stretch the incandescent sheet of flame,
+composed of several jets, and interpose friction, so as to prevent a
+too rapid ascent of hot gases.
+
+[Illustration: FIG. 3 and FIG. 4 REGENERATIVE BURNERS WITH INVERTED
+FLAMES.]
+
+The luminous focus is placed within a glass globe, C, mounted on the
+bell, B, of the heater; and the external air enters this bell,
+mingling with the products of combustion of the heating burner, R. The
+portion, D, of the annular passage, B, being made of a highly
+conductive metal, the gas becomes heated in passing to the burner, so
+that both gas and air are raised to the same temperature by the time
+they reach the orifices of the burner. Instead of prolonging the
+gas-pipe to the point of bifurcation, a chamber may be arranged
+immediately below the guide, for the gas and air to become intimately
+mixed by passing through several perforations or wire gauze, receiving
+the excess of heat from the white porcelain guide. The admission of
+gas to both the main and heating burners is regulated by a double
+valve in the pipe; but this arrangement may be used without any
+previous heating of the gas and air.
+
+Fig. 4 shows a similar arrangement to that above described, but
+reversed; the gas and air being previously heated by the products of
+combustion. The two pipes, D, lead the gas to the burner; and the
+incandescent sheet of flame is drawn over a white refractory
+substance, having in its center an orifice through which the hot gases
+rise to the upper portion of the burner. The luminous sheet is spread
+out all the better on account of this return of the flames, which also
+causes the mixture of air and gas to be more complete than when they
+rise directly. The gas escapes horizontally from the orifices of the
+annular burner, B, and mingles with the double current of hot air
+which rushes in above the flame inside the globe, and also below
+through the central portion of the burner.
+
+This lamp throws its light vertically downward; and its illuminating
+power may be increased by providing, above the incandescent sheet, a
+reflector, which diverts into a useful direction the rays thrown
+toward the ceiling. In this arrangement of lamp the flame is
+excessively condensed by its being turned back over the refractory
+guide; and this condensation greatly favors the production of light.
+On the other hand, the combustion of the gas is very perfect, because
+the currents of hot air are thrown directly upon the two sides of the
+flame; and thus the reciprocal action becomes more intense. Lastly,
+the division of the gas into a large number of small jets, in contact
+with which the hot air forms an intimate mixture, causes a greater
+quantity of molecules to partake in the combinations; thus affording a
+proportionate increase of temperature in a given space and time.
+
+[Illustration: FIG. 5. REGENERATIVE BURNER WITH FLAME DEFLECTED
+OUTWARD.]
+
+Owing to these various circumstances, the final effective duty of this
+burner is advantageous, so that it yields an illuminating power which
+may be put at from 200 to 250 per cent. above that of ordinary
+burners, and about 25 per cent. more than that of other regenerative
+burners. The flame is comparatively steady; the loss due to the
+friction over the white porcelain being almost eliminated, because the
+flame only presses upon the guide for a small portion of its surface,
+and is only spread out to the extent of its dark zone.
+
+The contact between the incandescent sheet of flame and the guide may
+be made as short as desired, and the motion of the gaseous mass be
+directed by a simple button placed in the center of the burner; thus
+giving the form shown by Fig. 5, which, however, differs from the
+previous figure in the fact that the inverted flame is directed
+outward instead of inward.
+
+In this arrangement the button, T, is fixed in the middle of the
+burner, which is made cylindrical and annular, or may consist of a
+ring of small tubes, to which the gas is led by a single pipe; leaving
+the whole "furnace" free for the circulation of air and the products
+of combustion. This is the most recent development of the principle
+patented by M. Somzee in 1882, viz., the formation of an illuminating
+sheet of flame, spread out laterally, while heating the gas and air by
+the products of combustion.
+
+Figs. 6 and 7 show two forms of burner designed especially to give
+economical results with a small consumption of gas. The former is an
+ordinary Argand burner in which hot air is introduced into the upper
+portion of the flame, so as to increase the activity of combustion.
+The luminous sheet of flame is then spread out by a metal disk
+attached to the end of the tube, D, which introduces the air into the
+flame. The outer air becomes heated in its passage through the wire
+gauze, T, which absorbs the heat liberated in the interior of the
+apparatus, and also that which is radiated from the incandescent sheet
+and reflected by a metal shield, P, surrounding the dark part of the
+flame.
+
+[Illustration: FIG. 6. FIG. 7. TYPES OF ECONOMICAL BURNERS.]
+
+It is the combustion of gas, without the production of useful luminous
+effect inside the shield, which supplies the reflected as well as
+radiated heat to the air. The temperature is still further increased
+by the heat transmitted to the metal portion of the burner, and
+absorbed by the wire gauze, between the close meshes of which the air
+from outside is forced to circulate. Air is admitted inside the flame
+by the chimney, D, placed above the focus, and in which it is raised
+to a high temperature by friction on the upper part of the lamp glass,
+at E, and afterward by its passage through the horizontal portion of
+the bent tube. This tube is impinged upon on the outside by the
+flames, and also by the products of combustion, so that it forms a
+veritable heater of the currents which traverse it.
+
+The introduction of hot air into the central portion of the sheet of
+flame is advantageously supplemented by the spreading out of the flame
+by means of the metal disk, without any possibility of its being
+divided. In this way a more intense heat is obtained, and consequently
+the illuminating power is considerably increased, by the uncombined
+carbon being more readily set free, and being thus kept longer in the
+flame, F. This burner, which may be constructed for a moderate gas
+consumption, gives remarkable results as regards illuminating power
+and steadiness; the abstraction of heat in no way impairing the
+luminosity of the flame, which preserves all its brightness.
+
+The Argand burner with double chimney, shown in Fig. 7, is also an
+economical one for a small consumption of gas. The air admitted to
+both the inside and the outside is raised to a high temperature by
+passing along the spirals of a second and transparent chimney, C¹,
+which surrounds the cylindrical glass, C. The gas itself is heated by
+passing through this hot chamber before reaching the outlet orifices;
+so that the mixture of air and gas takes place under the most
+favorable conditions for their perfect combustion.
+
+The burner is an ordinary Argand, which may terminate below in a small
+chamber for the gas and air to mingle. But this is not necessary; and
+the usual arrangement for mixing the air and gas may be adopted. The
+outer air enters at the top of the central chimney, C and passes into
+the annular space between the two glasses; then descends by the two
+spiral passages, which surround the cylindrical glass and terminate
+in a portion hermetically sealed by a brass plate attached to the
+supply-pipe. All the parts of the burner are thus surrounded by a
+highly-heated atmosphere, especially at the bottom of the double
+chimney; and it will be readily understood that, if the branches which
+lead the gas to the burner are constructed of a highly conductive
+metal, the gas will become heated in its turn by passing through
+passages raised to a high temperature.
+
+The elements are therefore dissociated or separated before their final
+combination; thereby raising the calorific and luminous effect to the
+highest possible degree. Such a burner can, of course, be made as
+small as may be required; thus lending itself admirably to the
+subdivision of illumination. The only precaution required is to
+properly proportion the sectional area of the hot-air passages to the
+radiant surface of the flame, so that the heat does not become too
+intense at the lower portion of the burner.
+
+Fig. 8 shows a double flame burner on the principle of Mr. Heron's,
+but with admission of hot air into the angle formed by the flames. As
+exemplified by Mr. Heron, if two equal batswing burners separately
+give a certain amount of light, on the two flames being brought into
+contact, so as to form a single flame, the luminosity is considerably
+increased, owing to the condensation of heat which results from their
+meeting. The two incandescent sheets are, as it were, forced into one
+another, so as to be combined.
+
+[Illustration: FIG. 8. DOUBLE FLAT-FLAME BURNER]
+
+The high-power burners of Douglass, Coze, Mallet, and others were
+designed on this principle; but its application to uninclosed burners
+was not very satisfactory, because the great cooling down of the inner
+surface of the flames by the strong draught of cold air impaired their
+illuminating power. To counteract this difficulty, M. Somzee adopts a
+heating burner, A, which he places between the two batswing burners,
+B, so that the products of combustion rise in the angle made by the
+two lighting flames, as shown; thus greatly increasing their
+luminosity while maintaining a low consumption of gas.
+
+M. Somzee also raises the illuminating power of an ordinary flat-flame
+burner by causing an obscure effluvium to traverse the dark portion of
+the flame. The effect of this is to increase the activity of
+decomposition in this portion, so that the particles of carbon are the
+more readily set free, and remain longer in suspension in the luminous
+zone. The obscure effluvium may be determined between two points by
+the electric current, or be caused by the heating of an imperfect
+conductor by the current; or, again, it may result from a metal
+conductor heated by the reactions produced in the middle of the flame,
+by separating the cone of matter in ignition. The effect may be
+compared with that obtained by the concentration of two sheets of
+flame; but in this case the sheets are formed by the constituent parts
+of one and the same flame, whence results a more complete utilization
+of the elements composing it. This system is, in fact, a
+simplification of the arrangement adopted in the double-flame burner
+seen in Fig. 8.
+
+Fig. 9 shows a reflecting and regenerative burner with double glass.
+The crown, made of metal polished on both sides, has a circular
+groove, G, for receiving the end of the central chimney, C, and
+presenting an annular aperture by which the products of combustion
+enter. The second glass, C¹, is fastened to the collar of the
+burner carrier, and does not come into contact with the metal crown;
+so as to allow the air to enter from outside for supplying the burner.
+The gas enters by the pipe, T, provided with a cock. This pipe is
+continued to the top of the apparatus, and there spreads out into the
+form of a dome; thus dividing into two compartments the trunconic
+chamber, S¹ S², whence the hot gas returns to the body of the burner,
+B.
+
+[Illustration: FIG 9. REFLECTING AND REGENERATING BURNER.]
+
+On the burner being lighted from below, the products of combustion
+rise in the inner chimney, and enter the heater, which they traverse
+through its entire extent, while impinging against the outside of the
+gas reservoir, to which they give up a large portion of their heat.
+They then pass by the passage, D, into the atmosphere or into a
+chimney. The air necessary for combustion enters at the top of the
+outer globe, and becomes highly heated in its passage through the
+space comprised between the two glasses of the burner. In this way it
+reaches the burner, and forms an intimate mixture with the small jets
+of gas which compose the flame. The gas, on leaving the supply-pipe,
+T, fills one of the compartments, S¹ S², of the heater, and then
+returns by the second compartment, and again descends by the casing of
+the supply-pipe, having its temperature still further raised by
+contact with the internal radiation of the flame.
+
+Under these conditions, all the parts of the burner are supplied by
+heated air, and the combustion becomes very active; thus increasing
+the intensity of the flame, and consequently that of the light
+afforded, while at the same time effecting a saving of 50 per cent. of
+gas. This burner may be made of any size, and for consumptions not
+exceeding that of an ordinary Argand. In fact, the gas is consumed at
+a low pressure, escaping with no greater force than that due to the
+heat of the products of combustion. It is sufficiently expanded on
+coming into contact with the current of hot air, the activity of which
+is regulated by the height of the apparatus, that is to say, by that
+of its two chimneys. The mixture is made in such proportion as to
+obtain from the gas and air as great a degree of luminosity as
+possible. The high temperature of the gas, and the independent means
+of heating the air and gas, constitute the essential principles of
+this burner.--_Journal of Gas Lighting._
+
+       *       *       *       *       *
+
+
+
+
+THE CLAMOND GAS BURNER.
+
+
+[Illustration: THE CLAMOND GAS BURNER.]
+
+In this burner, which is a French invention, the light is produced by
+burning ordinary coal gas within a basket of magnesia, which is
+thereby brought to a high state of incandescence, and from which a
+white, steady light is radiated. It may be said to consist of three
+different parts. The first and inner part is a central column, B, of
+fireproof material. The second part consists of two concentric
+cylinders placed round the inner column and communicating one with the
+other through the cross cuts, J. The third part is a china cup
+inclosing the other parts, and perforated with a number of holes. The
+gas burns in two different places. From A it passes directly through
+B, at the top of which it branches off through tubes to an annular
+chamber, D, from which it escapes through the openings, _a_, _a_, _a_,
+where combustion takes place. The other combustion occurs within the
+circular space, G, I, between the column and the inner of the two
+surrounding cylinders, through two channels, E E, in the lower part of
+the central column. The gas passes into a circular chamber, F F, and
+escapes through small holes in the upper partition of this chamber,
+where it burns. The product of this combustion passes put into K,
+through the cross cuts, J. The air entering through the holes, H L, of
+the outer china cup passes along the inner of the two concentric
+cylinders, which is heated to redness, and rises highly heated toward
+the upper annular burner, where the gas burns at _a_, _a_, _a_, in small
+separate flames, each entirely surrounded by the hot air. This insures
+perfect combustion of the gas within the basket of magnesia placed
+above, and which is thus brought to a state of incandescence. It will
+be seen from this description how simple and practical the
+arrangement is. It is claimed for the light produced that it will
+stand comparison with the electric light. Like that, it shows colors
+perfectly true, and will enable an observer to distinguish between the
+most delicate shades, allowing of the finest work being executed as by
+daylight. It is, moreover, stated to be perfectly steady. As the
+Clamond burner can be fixed to any gas bracket or lamp now in use, its
+adoption causes no other expense than the cost of the burner itself.
+There is no expensive installation, and when used in combination with
+the electric light, it is claimed that a uniform lighting will be
+obtainable instead of the unpleasant contrast between gas and
+electricity. Another important advantage obtained by the Clamond
+burner is the saving effected in the consumption of gas as compared
+with the same power of light obtained from ordinary burners.
+
+       *       *       *       *       *
+
+
+
+
+A NEW THERMO-REGULATOR.
+
+
+In the thermo-regulators which have been constructed heretofore, the
+heat has been regulated by the variation in the inflow of gas to the
+heating flame. The apparatus described below, and shown in the
+accompanying cut, taken from the _Zeitschrift fur Instrumentenkunde_,
+operates on an entirely different principle. The distillation and
+condensation process of a fluid heated to the boiling point in the
+vessel, A, is as follows:
+
+[Illustration]
+
+The steam passes first through the pipes, _a_ and _c_, into the
+serpentine tube, where it is condensed, and then flows through the
+tubes, _d_ and _b_, back into the vessel, A, if the cock, _r_, is
+closed, but if the said cock is open, it flows into the receptacle, K.
+When the liquid begins to boil the steam passes freely through the
+tubes, _d_ and _b_, part passing through the tube, _f_, out into the
+air, and the other part passing through the open cock, _r_, to the
+receptacle, K; but the condensed liquid soon closes these passages to
+the steam. At _h_ is an opening for a thermometer, _t_, and through
+this opening the liquid can be poured into the vessel, A. If the cock,
+_r_, is kept closed, the volume of liquid in the vessel, A, cannot be
+diminished, and the bath, B, must take the constant and uniform
+temperature of the steam in the vessel, A, as the vessel, B, is heated
+evenly on all sides.
+
+This apparatus can also be used as an air bath, in which case the
+vessel, B, is left empty and closed by a suitable stopper.
+
+       *       *       *       *       *
+
+
+
+
+PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.
+
+
+The accompanying engraving represents a simple apparatus, which any
+person accustomed to working glass can make for himself, and which
+permits of quickly, and with close approximation, estimating the
+density of a liquid. In addition, it has the advantage of requiring
+but a very small quantity of the liquid.
+
+It consists simply of a straight pipette, A B, to which is affixed
+laterally, at the upper part, a small U-shaped water gauge.
+
+The two branches of the gauge, as well as the pipette itself, are
+graduated into equal divisions. If need be, the graduating may be done
+by simply pasting on the glass strips of paper, upon which a graduated
+scale has been drawn. The zero of the pipette's graduation is exactly
+at the lower extremity, B. The graduation of the two gauge tubes
+extends in both directions from a zero situated near the center. The
+zeros of the two branches must correspond as exactly as possible, so
+that they shall be in the same horizontal plane when the apparatus is
+fixed upon a support. To render the apparatus complete, it only
+remains to adapt, at A, a rubber tube provided with a wire clamp, and
+terminating in a short glass tube for sucking through with the mouth.
+
+[Illustration: PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.]
+
+For taking the density of a liquid, we plunge the end, B, into it, and
+then suck, and afterward close the rubber tube with the clamp. It is
+essential that this latter shall hold well, so that the levels may
+remain constant.
+
+We now do the reading. Suppose, for example, we read 250.3 mm. on the
+pipette, and 147.7 mm. and 152 mm. on the branches of the gauge.
+Having these data, we loosen the clamp, and allow the liquid to flow.
+On account of capillarity, there remains a drop in B; and of this we
+read the height, say 6 mm. A height 250.5 mm - 6 = 244.5 mm. of liquid
+raised is, then, balanced by a column of water of 147.5 + 152 = 299
+mm.
+
+Now the heights of these two liquids is in the inverse ratio of their
+densities:
+
+  _d_   299.5
+  --- = -----, whence _d_ = 1.22.
+   1    244.5
+
+We obtain _d_ by a simple division.
+
+When the instrument has been carefully graduated, and has been
+constructed by an expert, the accuracy of the first two decimals may
+be relied upon. With a little practice in estimating the last drop, we
+may, in trying to estimate the density of water, even reach a closer
+approximation. In order to measure the height of the drop accurately,
+one should read the maximum height to which the liquid rises between
+the fall of two drops at the moment when the last ones are falling,
+since at that moment, and only at that, can it be ascertained that the
+lower level of the bubble is plane. The error in such reading does not
+reach half a millimeter, and, as a suitable height of the apparatus
+permits of having columns that vary between 13 and 30 centimeters, an
+error of this kind is but 1-300. This is the limit of precision of the
+method.
+
+The clamp might be advantageously replaced by a glass cock, or, better
+still, A might terminate in a rubber bulb; and a lateral tubulure
+might be fixed to the pipette, and be closed with a rubber stopper.
+
+This little apparatus is more easily maneuvered than any of those that
+have hitherto been devised upon the same principle. It is capable also
+of replacing areometers in ordinary determinations, since it permits
+of correcting the error in capillarity that is neglected in
+instruments; and, moreover, one can, when he desires to, easily verify
+for himself the accuracy of the graduation.--_La Nature._
+
+       *       *       *       *       *
+
+
+
+
+USEFUL BAGS, AND HOW TO MAKE THEM.
+
+By JOHN T. HUMPHREY.
+
+
+Since the papers on "Boot and Shoemaking," in vol. i. of _Amateur
+Work_, illustrated, I think nothing relating to the leather trades has
+appeared in it; and as there must be many among the readers of this
+magazine who have a desire to dive deeper into the art of manipulating
+leather into the various articles of utility made from that material,
+I will endeavor in the series of articles of which this is the
+commencement to furnish them with the necessary instructions which
+will enable them to do for themselves many things which now are left
+undone, or else have to be conveyed miles to some town where the
+particular business, or something akin to it, is carried on. To the
+colonist and those who live in out-of-the-way districts, it must be a
+matter of great regret to observe articles of use, where the material
+is in good condition, rapidly becoming useless owing to the inability
+of the possessor to do the necessary repairs. Again, it may be that
+the article is completely worn out, and the old proverb that "a stitch
+in time saves nine," will not be advantageously applied if carried
+out. In that case a knowledge of making new what we require, whether
+in order to replace something already worn out or as an addition to
+our store, must prove beneficial to the thrifty amateur. My object in
+writing these articles is not to deprive the mechanic of any portion
+of his legitimate occupation, but to assist those who live at a
+distance too great to be able to employ him, and who necessarily
+prefer any makeshift to the inconvenience of sending miles, and being
+without for days, an article which might possibly be set right in an
+hour or two.
+
+
+HOW TO MAKE BAGS.
+
+The old-fashioned carpet bag (Fig. 1) is still unsurpassed by any,
+where rough wear is the principal thing to be studied. Such a bag, if
+constructed of good Brussels carpeting and unquestionable workmanship,
+will last a lifetime, provided always that a substantial frame is
+used.
+
+[Illustration: FIG 1.--THE CARPET BAG.]
+
+Next in order comes the brief bag (Fig. 2), more extensively used than
+any other. For business purposes it is in great favor with bag users,
+being made in a variety of shapes, but all belonging to the same
+class. Here we have the shallow brief, deep brief, eclipse wide mouth,
+imperial wide mouth, excelsior, courier, and many others; but to know
+how to make one will be sufficient for all, the only difference being
+in the cut or style in which they are constructed.
+
+[Illustration: FIG. 2.--THE BRIEF BAG.]
+
+The cricket bat bag (represented in Fig. 3) is made on the same
+principle throughout as the carpet bag.
+
+[Illustration: FIG. 3.--THE CRICKET BAT BAG.]
+
+Frames and all necessary fittings required in making bags may be
+purchased of dealers.
+
+Care must be observed in choosing all the pieces necessary for a bag
+from the same pattern carpet, otherwise it will present an unsightly
+appearance when completed. There may be some who would prefer American
+cloth; this is thoroughly waterproof, and has a good appearance for
+some time, but, like all articles of imitation, it has only
+_cheapness_ to recommend it. If cloth is to be used (I mean American
+cloth), let it be the best that can be bought, that which is called
+"double-twill duck," if possible. As the making is the same whether
+cloth or carpet be used, it will be understood that the instructions
+for making apply to both.
+
+The following tools, which are few and inexpensive, will be required:
+A pair of clams (Fig. 4), cost 1s. 6d.; knife (Fig. 5), 6d.; half
+dozen awl blades, ½d. each; three or four boxwood handles, 1½d. each;
+3 foot rule, 1s.; hammer, 1s.; a packet of harness needles, size 4,
+cost 2½d. (these have blunt points); a bone (Fig. 6) will also be
+required for rubbing the stiffening into place, cost about 3d.; and a
+ball each of hemp and wax for making the sewing threads--hemp 2½d.,
+wax ½d. For making holes in the bottom where the nails or studs are
+fixed, a large sewing-awl will be required; this will probably have to
+be bought at a saddler's; the other tools can all be obtained at any
+grindery and leather seller's.
+
+[Illustration: FIG. 4--Pair of Clams. FIG. 5--Knife. FIG. 6--Bone
+Rubber. FIG. 7--Method of Measuring Registered Frame: A to A, Top of
+Sides; A to B, Top of Gussets. FIG. 8--Pattern of Bottom, Showing
+Place of Nails. FIG. 9--Side Pattern Folded. FIG. 10--Gusset Pattern
+Folded. FIG. 11--Pattern for Gusset Stiffening. FIG. 12--Handle,
+Showing Distance of Rings.]
+
+The awl blades mentioned above are of two kinds, and either may be
+used for this work. Those generally used are of a straight diagonal
+shape, making a perforation the shape of a diamond, <>*; the others are
+perfectly round, tapering gradually to a fine point. To fix them in
+the boxwood handles, place the blade in a vise, leaving the unpolished
+part above the jaws; hold the handle above this, and commence driving
+it down, taking care that the blade is penetrating the middle of the
+handle. Continue tapping the handle until the ferrule reaches the
+polished part of the blade; it will then be in far enough.
+
+  * Transcriber's Note: Original diamond vertical instead of horizontal.
+
+A good serviceable pair of clams may be made by taking two staves of a
+good-sized barrel, and cutting about 10 inches off the end of each.
+Screw together with three screws (as in Fig. 4), and shape the
+uppermost ends so that the outsides meet in a sharp ridge along the
+top; this will give a flat surface within the mouth, by which a hold
+of the work may be obtained. A two-inch screw will be long enough for
+the bottom, which must be turned in as tightly as possible; the others
+must not be less than 3 inches, as there will be a space of 1½ or two
+inches between the staves at the part where they are inserted. Screw
+these just tight enough to give a good sharp spring to the mouth of
+the clams when they are pressed open; this will insure the work being
+held firmly while being sewn. Sandpaper them over to give a smooth
+appearance, and these will be found as useful as bought ones.
+
+A piece of basil leather will be required for the bottom and welts of
+the bag. This may be purchased at a leather seller's with the tools.
+Cut out the bottom first; the welts may be cut from any narrow pieces.
+These must be cut seven-eighths of an inch wide, then folded over, and
+lightly hammered down. This brings the two edges together, and when
+placed in position, they should lie evenly between the edges of the
+material. A piece of string may be laid in the welt to give it a
+fuller appearance if the leather is very thin.
+
+The following dimensions of bags when made up will enable the maker to
+choose the most useful size:
+
+  No. 1, 16 by 14 inches; No. 2, 19 by 16 inches;
+  No. 3, 21 by 17 inches; No. 4, 24 by 18 inches.
+
+The sizes of frames and parts when cut will be as follows:
+
+          Frame.      Sides.     Bottom.    Gussets.
+
+  No. 1, 15 inches  16½ by 15½  16½ by 5½  15½ by 5½
+  No. 2, 18 inches  19½ by 17½  19½ by 6   17  by 6
+  No. 3, 20 inches  21½ by 18½  21½ by 6½  18½ by 6½
+  No. 4, 23 inches  24½ by 19½  24½ by 6½  19½ by 6½
+
+Taking No. 1, 16½ inches will be the length of sides and 15½ inches
+the depth. The gussets are also 15½ deep, the width being 5½, the same
+as the bottom. Take 1½ inches from the depth of these to allow for
+covering the frame, and ½ inch from the length to allow for the seams,
+and we have a bag 16 inches long by 14 inches deep.
+
+And now to commence. Arrange the pieces of carpet on the board, and
+mark off the size of each part required with a piece of chalk or
+pipeclay. By cutting with the carpet, laying the right side up, we
+shall be able to see that the pattern of it will be in the same
+direction on both sides of the bag when made up. We next take the ball
+of hemp, and by pushing the finger through the hole in the center of
+it, drive out the end. To use the hemp from the inside is much the
+best way, because the ball will stand perfectly still, whereas, if
+started from the outside, it will be darting in all directions about
+the floor of the workroom, and entwining itself around any obstacle
+which lies there, unless it is placed securely in a box and drawn out
+through a hole in the center of lid.
+
+A hook must be fixed in some convenient place to make the waxends on,
+or, as they are called in the trade, "threads," which term it will be
+as well to call them by here; thus a _four-cord thread_ means a thread
+or waxend containing four strands of hemp, a six-cord contains six
+strands, and so on. One of the greatest difficulties for the amateur
+is to produce a well-formed thread. He generally finds it thicker a
+few inches from the point than at any other part. These are known in
+the trade as bull-necked threads; and as the mechanic finds it
+difficult to use them when his employer starts a new apprentice and
+gives him this job for the men, I must impress on the worker here the
+necessity of making them as perfect as possible. It would be as well
+if a little practice was given at breaking the hemp in the way which
+produces good points. Better waste a few yards of hemp than be
+compelled to abandon a thread after making only a few stitches with
+it.
+
+Gripe the hemp firmly between the thumb and forefinger of the left
+hand, leaving about eight or nine inches hanging loosely down; lay
+this over the thigh of the right leg, and with the right hand rub it
+in a downward direction, which will cause the twisted strand to
+loosen. One good stroke should be sufficient; if not, it must be
+repeated until the fibers forming the strand are quite loosened. By
+holding it close to the end with the right hand, and giving it a jerk
+with the left, the fibers will break, and the ends of the strands
+formed in this way are placed at a little distance one above another,
+which, when twisted, form a smooth, tapering point.
+
+To cast off a thread the proper way is to stand at a distance of about
+three feet from the hook previously mentioned, and by holding the end
+of the hemp in the left hand, pass it over the hook and bring it down
+with the right, then holding with the left and breaking as above. When
+sufficient strands to form the thread have been broken off, carefully
+examine the points to see that they taper properly, and have no lumps
+in them. Rub the wax up and down a few times, so that the thread may
+be properly waxed on that portion which will be inside when twisted.
+Hold the two ends in the left hand, and with the right roll each end
+separately down the right leg a sufficient number of times to twist
+the thread throughout. Judgment will be required in this operation, or
+the thread will be a constant source of trouble if it is over-twisted.
+Wax it again, and then it is ready for use. See that the points are
+well waxed, then take a needle and pass the point of the thread
+through the eye until it nearly reaches that part which would stop its
+progress.
+
+It must now be turned down on to the thicker portion and carefully
+twisted. Smooth it down, then take the other end of thread and another
+needle, and fasten it on in the same way. In selecting the awl to be
+used, do not take a very large one. The hole should be just large
+enough for the thread to require a slight pull to get it through.
+
+To commence sewing take one side and a gusset and place them evenly
+together, the right side of the material being inside, and fix them in
+the clams. Slip the welt as previously described between the edges,
+and pass the awl through the lot. Drive it perfectly straight, as upon
+this chiefly depends a nice seam when turned. Draw out the awl, and by
+following the point, pass up the bottom needle with the left hand.
+This should be taken by the thumb and forefinger of the right hand and
+the thread pulled through half its length, so forming a thread of
+equal length on each side. Make another hole with the awl about
+one-third of an inch from the first. This gives the length of stitch.
+Pass up the bottom needle as before into the right hand, the top
+needle descending to the bottom immediately after. Take hold of this
+with the left hand and pull through the threads simultaneously top and
+bottom, until the extremity on each side lies on and forms the stitch.
+Be careful that in pulling in the latter part each thread closes at
+the same time, thereby preventing a crooked seam. Repeat until the
+seam is finished, then take the other gusset and place in position.
+Sew this, then take the other side of bag and sew to the gussets. You
+will then have something in the shape of a bag, minus the bottom. Take
+this next, and fix each corner to one of the seams previously made,
+and stitch it carefully round, placing a welt in as before. At the end
+of each seam a stitch or two back should be taken or the thread tied
+over to prevent it opening.
+
+The outside of the bag being inward, it must now be turned previous to
+stiffening and framing. The turning is done by placing the bag over
+the left arm, and with the right hand commence pushing in one of the
+corners, then the opposite one until that end is reversed. Then serve
+the other end in a similar manner, and smooth each seam along.
+
+We now take a piece of stout millboard (an old ledger book cover will
+do if large enough), or, if purchased with the frame, ask for a two
+pound board: this will cost about 4d., and be sufficient for several
+bags. Cut it quarter of an inch less than the bottom all round, and
+see that it fits before gluing it in. To do this, place one end within
+the seams at one end of the bag, and by lifting it in the middle press
+in the other, when the stiffening will lie within the four seams at
+the bottom. Having fitted it satisfactorily, take it out again and
+glue it well with some good hot glue. This must be neither too thick
+nor too thin. The best way to prepare it is to lay some glue in cold
+water for twelve hours. It will absorb sufficient water in that time,
+and can be boiled up without any further preparation. The quicker it
+is fixed after the glue is put on the better. A brush similar to a
+paint brush will be the best to apply it with, and need not cost more
+than 6d. After the gluing, lay it aside for a few hours to allow it to
+thoroughly set, during which time the making of the handles can be
+proceeded with. On some bought bags these are very common, and seldom
+last more than a few months; the usual plan being to take a piece of
+rope about the size of a clothes line and roll a piece of brown paper
+round it, covering it afterward with a piece of basil leather.
+
+Procure two pieces of brown harness leather--the shoulder of the hide
+is most suitable--from a saddler, 11 inches long by 1-1/8 inches wide,
+round the four ends, and make a compass mark 1/8 of an inch from the
+edge all round for the stitching. Take a piece of line as above, and
+place within the leather, which most likely will have to be damped to
+make it draw round easier. Leave 1½ inches from each end for sewing to
+the bag, the line also being so much less than the full length of the
+handles. Having sewn them, flatten the ends and bend the handles into
+a semicircular shape, and leave them to dry.
+
+By this time the glue holding the stiffening to the bottom of the bag
+will be set, so the next move will be to put in the studs or nails.
+Take the largest size awl and make five punctures through the bottom,
+about three-quarters of an inch from each corner and one in the
+center, as in Fig 8; push the nails through and turn down each of the
+two claws in an opposite direction, tap them with a hammer to make
+them lie closer, and also to prevent them from becoming loose. This
+done, we next take the frame and remove the key-plate from it.
+
+Fold the sides of the bag well over the frame, so that the stitching
+will get a good hold of the part that goes inside. Put a stitch
+through at each corner to hold it, and see that it sets perfectly true
+on the frame. A space is left between the two plates of iron forming
+the frame, which allows of the bag being sewn through it. Fix the
+key-plate by riveting inside. Sew the bag from one corner of frame to
+the other corner on each side, leaving the gussets unstitched. It is
+now ready for the lining. Let this be good, as it will greatly add to
+the durability of the bag if strong. Coarse linen at 8d. to 10d. per
+yard is the best material for this purpose. The sides and bottom may
+be cut in one piece; the length of this will be twice the depth of one
+side of carpet (less the part which folds over the frame) and the
+width of the bottom. The width of this piece throughout to be a half
+inch less than the outsides were cut. The gusset lining will want to
+be the same width as the gusset, but an inch less in length will do.
+The seams of the lining may be stitched with an ordinary household
+sewing machine if good thread is used. When made, place the lining
+inside the bag, see that it is well down at the bottom, turn in the
+top edge all round to the required size, and fix in as follows: Take a
+long carpet needle and a length of thread, pass the needle through the
+lining at the folded ridge and bring it up again through the same at a
+distance of an inch or so. This forms a stitch within the lining; pass
+the needle through one of the stitches made in sewing in the frame and
+repeat as before, carefully observing that the lining falls into its
+proper place as it is being sewn in. Continue in this way until the
+two sides are done, leaving only the gussets and gusset lining to be
+united. This is done by folding the edges inward and sewing them
+together, the frame joints moving freely between the gussets and
+lining. We have now only the handles to put on and it is complete. Sew
+these on with a five cord thread well waxed. To protect the lock
+against being unduly strained when filled, a strap and buckle may be
+put on between the handles and each end of the frame, as in Fig. 3.
+
+Next in order is the cricket bat bag, which should always be comprised
+in the outfit of the amateur cricketer, as well as of the
+professional. In making this we follow the instructions given for the
+carpet bag. It may be made either of carpet, tan-canvas, or leather,
+the latter, of course, being the strongest and most expensive. Carpet
+will not require to be described, but a brief description of
+tan-canvas and leather may be of service to the amateur in assisting
+him to choose something for himself.
+
+Tan-canvas, as used for bags and portmanteaux, is a strong, coarse
+material of a brown color; it wears well, and has one advantage over
+carpet--it is thoroughly waterproof.
+
+Leather is, of course, superior to carpet or canvas, but there are a
+few tricks in its manufacture which it may not be out of place here to
+mention as a caution to the amateur that the old saying, "There's
+nothing _like_ leather," is a thing of the past where the general
+appearance of an article is meant. The genius of the inventor has
+produced machinery which gives to paper, linen, and other stuffs the
+appearance of the genuine article, whereas it does not contain one
+particle of it. At one time, when a hide of leather was required to be
+of the same thickness all over it, the currier would work at the flesh
+of the skin with a shaving knife, gradually scraping the thick parts
+away until it was reduced to the required substance. Now it is done
+in a few minutes. The hide is passed whole between the rollers of a
+splitting machine against the sharp edge of a knife, which reaches
+from one side of the machine to the other, a distance of 10 or 12
+feet. This knife is so gauged that any thickness can be taken off at
+one operation, the part taken off resembling the hide in size and
+shape. The top or grain of the hide is then dressed and finished off
+brown, if for brown hides; or, if to be used for enameled hides, they
+are dyed and japanned. These are called either brown or enameled
+cow-hides, according as they are finished off, and are used for all
+the best class of Gladstone, brief, and other bags. The bottom or
+fleshing of the hide is also dyed and japanned, and when finished,
+exactly resembles in appearance the hide itself, and is very difficult
+for the novice to tell when made up into bags or any other article.
+These are called _splits_, and having had the best part of the skin
+taken from them, do not wear one-fourth the time the grain will. The
+black enamel soon chips off, which gives them a worn-out appearance.
+
+To make a bag 36 inches by 12 inches by 8 inches requires a frame 36
+inches long, the sides 36½ inches by 14 inches, gussets 14 inches by
+8½ inches, bottom 36½ inches by 8 inches. The lining will be 36 inches
+by 12 inches for the sides, gussets 13 inches by 8 inches, bottom 36
+inches by 8 inches. For the handles two pieces of leather 12 inches by
+2 inches. The straps and chapes are sewn on quite close to the frame,
+straps 10 inches long by 1 inch, chapes 4½ inches by 1 inch. Cut a
+slit in the middle of the chape for the buckle tongue to go through,
+and pare the under side at the end so that it is not too lumpy when
+sewn on to the bag. Cut two loops 3 inches long by ¾ inch wide for the
+points of straps to go through.
+
+The brief bag must be made of leather, and as there is the same amount
+of work in making it, whether it be of split or hide, it will be sure
+to give greater satisfaction if the latter is chosen. The manufacture
+of this bag differs considerably from the others. The sides and
+gussets in the carpet bag are cut straight from top to bottom, but in
+the brief bag they must be shaped to fit the frame, and give it a more
+comely appearance. The frame, as before described, is quite different.
+The way to commence with this bag is to open the frame as in Fig. 7,
+so that it will lie perfectly flat upon the bench. With the rule
+measure it carefully between the corners, A, A, and again at A, B. The
+distance between A and B being less when the frame is open than when
+closed, an additional ½ inch must be added to allow the gusset to bend
+freely round the hinge. Having correctly taken these measurements, get
+a sheet of brown paper and fold it in the middle; the reason for this
+is to allow of each side of the pattern taking the same curve at the
+swelled part. Cut the pattern for the sides first by ascertaining half
+the distance, A, A, and marking it on to the edge of the paper,
+measuring from the folded edge toward the ends. Next mark on the
+folded edge the depth you intend the bag to be, allowing in this, as
+in the carpet bag, 1½ inches for covering the frame. The depths of
+brief bags vary so much that I will give these only as a guide,
+leaving my readers to add or reduce as their fancy guides them; but if
+they should strictly adhere to these given below, I am certain they
+will find them very useful sizes.
+
+For a 12 inch frame cut the sides and gussets 10½ inches in depth;
+when made up, these will be 9 inches from the frame to the bottom. For
+a 14 inch frame add 1 inch, and for a 16 inch add 2 inches. This will
+make these 10 inches and 11 inches in depth respectively when made up,
+and either of these will be found a very useful bag for many purposes.
+The width of the bottoms to be cut 5 inches, 5½ inches, and 6 inches,
+the 5 inch, of course, for the 12 inch bag, the 5½ inch for the 14
+inch, and the 6 inch for the 16 inch. The depth having been decided
+upon, and marked on the folded edge of the paper, make another mark
+the same distance from the edge at the first mark, H. The bottom of
+the sides being 1 inch longer than the top, add ½ inch to the
+measurement of the top of pattern when the bottom part is marked off
+at J L. Draw a curved line between H L, as in Fig. 9, and cut through
+the two thicknesses of paper at one time, keeping them well together
+to insure them being alike. The gusset pattern may be cut in the same
+way, D to D, Fig. 10, being half the distance of A B, Fig. 7, and the
+½ inch added for going round the joint; E E, the swelled part, which
+bends into the bag when the frame is closed, and also allows it to
+open perfectly square; F F is half the width of the bottom of gusset.
+A pattern for the bottom of the bag may be made by folding a piece of
+paper each way to get the length and width; make a small hole through
+the four thicknesses, open it and mark it from hole to hole, using the
+rule as a guide. This will be found to be perfectly accurate.
+
+To cut out the bag, lay the leather on the bench, enameled side
+downward, and see that the patterns lie on it so the creases will run
+from the top to bottom of the bag when made. The sides must be taken
+first, and as they are more exposed than any other part, they should
+be taken from the best part of the hide. Take the gussets next, then
+the bottom. The welts are taken from the cuttings which are left. To
+make the handle, glue a lot of odd pieces together about 6½ inches
+long, ½ inch wide, and the same thickness, and when dry pare the edges
+away until it is perfectly round and slightly tapering toward each
+end. It is then divided and glued top and bottom to a strip of good
+leather cut to shape, Fig. 12, which is passed through the rings at
+each end, and turned back to form a shape. Put a few stitches through
+close to the rings before the fittings are glued on, and cover with a
+piece of cow-hide long enough to go through the two rings and along
+the under side, then stitch it. Trim and dye the edges, rubbing them
+afterward with a piece of cloth to produce a polish. Before making the
+handle, the plates must be on the rings, or it will prove a difficult
+job to get them on afterward.
+
+The stiffening for the bottom will be cut as if for a carpet bag. Fig.
+11 represents the stiffening for the gussets, and is cut from a board
+half the thickness of that used for the bottom.
+
+The linings may be cut from the outside patterns by reducing them the
+1½ inches, allowed for covering the frame, and 1/8 inch for each welt.
+A lining of scarlet or blue roan greatly adds to the appearance and
+durability of a bag. A skin large enough for a 14 inch or 16 inch will
+cost about 3s.
+
+Cow-hide for the outside is sold at 1s. 8d. per square foot, but the
+leather sellers frequently have pieces large enough for making a bag
+which they will sell at a slight reduction, and which answers this
+purpose as well as cutting a hide. In seaming the bag, take care not
+to wrinkle it in the clams. The welts in this must reach only to the
+frame, the same as in the carpet bag; the rest of the seam must be
+neatly closed and rubbed down, so that it will not be lumpy on the
+frame. Before turning the bag warm it before the fire, especially if
+it is cold weather. Glue in the bottom stiffening first, and then the
+gussets, rubbing them well down with the bone. When these are set,
+prepare for the operation of framing. Fold one of the sides to get the
+middle of it, cut a hole for the lock barrel about 1¼ inches from the
+edge, and press it over. Be careful not to cut it too large or the
+hole will show. Pierce a hole through the leather for the lock plate,
+press this tightly on the frame, and clinch the clams underneath, to
+hold it securely. Make holes for the handle plates and fasten them on
+in a similar manner. Two slits must be cut near the middle of the
+other side of bag, about ¾ inch from the edge, for the hasp to go
+through. This bag must be sewn to the frame all round, and care must
+be taken that a sufficient fullness is allowed in the middle of the
+gusset to enable it to close easily round the joints of the frame. A
+thumbpiece must be sewn on the bag at the hasp to open it by. The
+lining of this bag is sewn through the frame all round in the same
+manner as the side linings of the carpet bag.
+
+I hope my readers will not think that I have gone too much into
+details. It is in small things that so many failures take place. As it
+is much easier to do anything when you are shown than when so much has
+to be guessed, it is my desire to make the road for beginners as
+smooth as possible, which must be my excuse if any is required. It is
+as well that those who intend to turn their attention to working in
+leather should begin by making a bag; the experience gained in
+cutting, fitting, putting together, and finishing will be useful when
+larger and more difficult pieces of work are undertaken.--_Amateur
+Mechanics._
+
+       *       *       *       *       *
+
+
+
+
+MOLASSES, HOW MADE.
+
+
+The _New England Grocer_ says that the manufacture of molasses is
+really the manufacture of sugar up to a certain stage, for molasses is
+the uncrystallized sirup produced in the making of sugar. The methods
+of manufacture in the West Indies vary very considerably. In the
+interior and on the smaller plantations it is made by a very primitive
+process, while on the larger plantations all the appliances of modern
+science and ingenuity are brought to bear. Each planter makes his own
+sugar. It is then carried to the sea coast and sold to the exporters,
+by whom it is shipped to this country. The quality and grade of the
+molasses varies with each plantation. Two plantations side by side may
+produce entirely different grades. This is owing to the soil, which in
+Porto Rico and other localities in the West Indies seems to change
+with almost every acre. The cane from which the sugar and molasses is
+made is planted by laying several pieces of it in holes or trenches.
+The pieces are then covered with earth to the depth of two or three
+inches. In about two weeks sprouts appear above the surface. Then more
+earth is put in, and as the sprouts grow, earth is added until in
+three or four months the holes are filled up. The planting is done
+from August to November, and the cutting progresses throughout the
+greater part of the year. The cane grows to a height of seven or eight
+feet, in joints each about a foot long.
+
+When the cane is in proper condition for cutting, as shown by its
+appearance, an army of workmen take possession of the field. Each is
+armed with a long, broad knife, like a butcher's cleaver. They move
+down the lines of cane like an army, and while the cutting is going on
+the fields present an interesting sight, the sword-like knives
+flashing in the sun, the 300 or 400 laborers, the carpet of cut cane,
+the long line of moving carts, and the sea of standing cane, sometimes
+extending for miles and miles, stirred by the breeze into waves of
+undulating green. The laborers employed on these plantations are
+largely negroes and Chinese coolies. When the cane is ripe, they
+proceed to the field, each armed with a _matchet_. Spreading over the
+plantation, they commence the cutting of the cane, first by one cut at
+the top, which takes off the long leaves and that part which is
+worthless, except as fodder for the cattle. A second cut is then given
+as near the root as possible, as the nearer the ground the richer the
+cane is in juice. The cut cane is allowed to fall carelessly to the
+ground.
+
+Other workmen come with carts, pick it up, tie it in bundles and
+carry it to the mill. The cutting of the cane is so adjusted as to
+keep pace with the action of the mill, so that both are always at
+work. Two gangs of men are frequently employed, and work goes on far
+into the night during the season, which lasts the greater part of the
+year.
+
+As before stated, some of the methods of manufacture are very simple.
+In the simplest form, the sugar cane is crushed in a mortar. The juice
+thus extracted is boiled in common open pans. After boiling a certain
+length of time, it becomes a dark colored, soft, viscid mass. The
+uncrystallized sirup is expressed by putting the whole into cloth bags
+and subjecting them to pressure. This is molasses in a crude state. It
+is further purified by reboiling it with an addition of an alkaline
+solution and a quantity of milk. When this has continued until scum no
+longer arises, it is evaporated and then transferred to earthen jars.
+After it has been left for a few days to granulate, holes in the
+bottom of the jars are unstopped, and the molasses drains off into
+vessels placed to receive it. Another process of extracting molasses
+is as follows: By various processes of boiling and straining, the
+juice is brought to a state where it is a soft mass of crystals,
+embedded in a thick, but uncrystallized, fluid. The separation of this
+fluid is the next process, and is perfected in the curing house, so
+called. This is a large building, with a cellar which forms the
+molasses reservoir. Over this reservoir is an open framework of
+joists, upon which stands a number of empty potting casks. Each of
+these has eight or ten holes bored through the bottom, and in each
+hole is placed the stalk of a plantain leaf. The soft, concrete mass
+of sugar is removed from the cooling pans in which it has been brought
+from the boilers and placed in the casks. The molasses then gradually
+drains from the crystallized portion into the reservoir below,
+percolating through the spongy plantain stalks.
+
+On the larger plantations, machinery of very elaborate description is
+used, and the most advanced processes known to science are employed in
+the manufacture. The principle is, however, the same as has been seen
+in the account of the simpler processes. On these larger plantations
+there are extensive buildings, quarters for workmen, steam engines,
+and all the necessary adjuncts of advanced manufacturing science. In
+the sugar mills the cut cane is carried in carts to the mill. It is
+then thrown by hand upon an endless flexible conductor which carries
+the cane between heavy crushers. The great jaws of the crushers press
+the cane into pulp, when it is thrown aside automatically to be carted
+away and used as a fertilizer. The juice runs off in the channels of
+the conductor into huge pans. The juice is now of a dull gray color
+and of a sweet, pleasant taste, and is known as _guarapo_. It must be
+clarified at once, for it is of so fermentable a nature that in the
+climate of Porto Rico it will run into fermentation inside of half an
+hour if the process of clarifying is not commenced. The pans into
+which the juice is conducted are pierced like a colander. The liquor
+runs through, leaving the refuse matter behind. It is then forced into
+tanks by a pump and run to the clarifiers, which are large kettles
+heated by steam. Lime is used to assist the clarification. It is then
+filtered into vats filled with bone black. The filtering is repeated
+until the juice changes color, when it is conveyed to the vacuum pans.
+It has now become a thick sirup. It is then pumped into the sirup
+clarifiers, skimmed, and again run through bone black, and finally is
+conducted into another kettle, where it is allowed to crystallize. The
+sirup that fails to crystallize is molasses, and it is here that we
+catch up with what we started after. To extract the molasses from the
+crystallized mass of sugar, we must go to the purging house. This is
+similar to the building spoken of in connection with the simpler
+process. It is of two stories. The upper floor is merely a series of
+strong frames with apertures for funnel-shaped cylinders. The sugar is
+brought into the purging house in great pans, which are placed over
+the funnels. The pans are pierced with holes through which the
+molasses drains off into troughs which are underneath the floor, all
+running to a main trough. From thence the molasses runs into vats,
+called _bocoyes_, each of which holds from 1,200 to 1,500 gallons. The
+hogsheads in which the molasses is brought to this country are
+manufactured principally in Philadelphia and taken to the West Indies.
+They are placed in the hold of the vessel and the molasses pumped into
+them. The government standard for molasses is 56 degrees polarization.
+When not above that test, the duty is four cents per gallon. Above it
+the duty is eight cents. This tends to keep molasses pure, as the
+addition of glucose increases the quantity of sugar and therefore of
+the polarization, and would make necessary the payment of increased
+duties. The adulteration of molasses is therefore largely if not
+wholly done after it is out of bond and in the hands of the jobber.
+
+       *       *       *       *       *
+
+
+
+
+PRIMITIVE IRON MANUFACTURE.
+
+
+We are indebted for the illustrations and the particulars to Dr.
+Percy's invaluable book on iron and steel (probably it is not saying
+too much to describe it as the best work on the subject ever written).
+
+[Illustration: SECTION OF INDIAN BLAST FURNACE AND BLOWING MACHINE.]
+
+Fig. 1 shows a sectional elevation, and Fig. 2 shows a plan of furnace
+and bellows and tuyeres, indeed, an entire ironworks plant used in
+India, not only now, but, so far as we can gather, from time
+immemorial. The two figures give a sufficiently clear idea of the form
+of furnace used in Lower Bengal, in which portion of our Indian empire
+there are entire villages exclusively inhabited by iron smelters, who,
+sad to relate, are distinguished from the agricultural villages
+surrounding them by their filth, poverty, and generally degraded
+condition. There are whole tribes in India who have no other
+occupation than iron smelting. They, of course, sink no shafts and
+open no mines, and are not permanent in any place. They simply remain
+in one place so long as plentiful supplies of ore and wood are
+obtainable in the immediate vicinity. In many cases the villages
+formerly inhabited by them have passed out of existence, but the
+waste, or rather wasted products, of their operations remain.
+
+The furnace shown in Figs. 1 and 2 is built of the sandy soil of the
+district, moistened and kneaded and generally strengthened by a sort
+of skeleton of strips of flexible wood. In form it varies from a
+cylinder, more or less circular, diverging into a tolerably acute
+cone, the walls being about 3 in. thick. The height is generally
+about 3 ft. and the mean internal diameter about 1 ft., but all these
+dimensions vary with different workmen and in different localities.
+There are two apertures at the base of the furnace; one in front,
+about 1 ft. in height, and rather less in width than the internal
+diameter of the furnace, through which, when the smelting of one
+charge is finished, the resulting mass of spongy iron is extracted,
+and which during the smelting is well plastered up, the small conical
+tuyere being inserted at the bottom. This tuyere is usually made of
+the same material as the furnace--namely, of a sandy soil; worked by
+hand into the required form and sun-dried; but sometimes no other
+tuyere is employed than a lump of moist clay with a hole in it, into
+which the bamboo pipes communicating with the bellows are inserted.
+The other aperture is smaller, and placed at one side of the furnace,
+and chiefly below the ground, forming a communication between the
+bottom of the furnace chamber and a small trench into which the slag
+flows and filters out through a small pile of charcoal. It is this
+slag being found in places where iron is not now made that shows that
+iron smelting was an occupation there, perhaps many centuries before.
+
+The inclined tray shown at the top of the furnace on Fig. 1 is made of
+the same material as the furnace itself, and when kneaded into shape
+is supported on a wooden framework. On it is piled a supply of
+charcoal, which is raked into the furnace when required.
+
+The blowing apparatus is singularly ingenious, and is certainly as
+economical of manual labor as a blowing arrangement depending on
+manual labor well can be. A section of the bellows forms the portion
+to the right of Fig. 1, showing tuyere forming the connection between
+bellows and furnace. It consists of a circular segment of hard wood,
+rudely hollowed, and having a piece of buffalo hide with a small hole
+in its center tied over the top. Into this hole a strong cord is
+passed, with a small piece of wood attached to the end to keep it
+inside the bellows, while the other end is attached to a bent bamboo
+firmly fixed into the ground close by. This bamboo acts as a spring,
+drawing up the string, and consequently the leather cover of the
+bellows, to its utmost stretch, while air enters through the central
+hole. When thus filled, a man places his foot on the hide, closing the
+central hole with his heel, and then throwing the whole weight of his
+body on to that foot, he depresses the hide, and drives the air out
+through a bamboo tube inserted in the side and communicating with the
+furnace. At the same time he pulls down the bamboo with the arm of
+that side. Two such bellows are placed side by side, a thin bamboo
+tube attached to each, and both entering the one tuyere; and so by
+jumping on each bellows alternately, the workman keeps up a continuous
+blast.
+
+[Illustration: Fig. 2.--PLAN OF INDIAN BLAST FURNACE AND BLOWING
+MACHINE.]
+
+The Figs. 1 and 2 are taken from sketches, and the description from
+particulars, by Mr. Blandford, who was for some years on the
+Geological Survey of India, and had exceptional opportunities in his
+journeyings of observing the customs and occupations of the Indian
+iron smelters. The blowing machine is an especially wonderful and
+effective machine, and was first described and illustrated by Mr.
+Robert Rose, in a Calcutta publication, more than half a century ago.
+He also had seen it used in iron making in India.--_Colliery
+Guardian._
+
+       *       *       *       *       *
+
+
+
+
+WOOD OIL.
+
+
+Wood oil is now made on a large scale in Sweden from the refuse of
+timber cuttings and forest clearings, and from stumps and roots.
+Although it cannot well be burned in common lamps, on account of the
+heavy proportion of carbon it contains, it is said to furnish a
+satisfactory light in lamps specially made for it; and in its natural
+state it is the cheapest illuminating oil. There are some thirty
+factories engaged in its production, and they turn out about 40,000
+liters of the oil daily. Turpentine, creosote, acetic acid, charcoal,
+coal-tar oils, etc., are also obtained from the same materials as the
+wood oil.
+
+       *       *       *       *       *
+
+
+
+
+SOAP.
+
+By HENRY LEFFMANN, M.D.
+
+
+Although the use of soap dates from a rather remote period, the
+chemist is still living, at an advanced age, to whom we are indebted
+for a knowledge of its composition and mode of formation. Considerably
+more than a generation has elapsed since Chevreul announced these
+facts, but a full appreciation of the principles involved is scarcely
+realized outside of the circle of professional chemists. Learned
+medical and physiological writers often speak of glycerin as the
+"sweet principle of fats," or term fats compounds of fatty acids and
+glycerin. Indeed, there is little doubt that the great popularity of
+glycerin as an emollient arose from the view that it represented the
+essential base of the fats. With regard to soap, also, much erroneous
+and indistinct impression prevails. Its detergent action is sometimes
+supposed to be due to the free alkali, whereas a well-made soap is
+practically neutral.
+
+A desire to secure either an increased detergent, cleansing, or other
+local effect has led in recent years to the introduction into soaps of
+a large number of substances, some of which have been chosen without
+much regard to their chemical relations to the soap itself. The result
+has been the enrichment of the materia medica with a collection of
+articles of which some are useful, and others worse than useless. The
+extension of the list of disinfectant and antiseptic agents and the
+increased importance of the agents, in surgery, have naturally
+suggested the plan of incorporating them with soaps, in which form
+they will be most convenient for application. Accordingly, the
+circulars of the manufacturing pharmacists have prominently displayed
+the advantages of various disinfecting soaps.
+
+Among these is a so-called corrosive sublimate soap, of which several
+brands are on sale. One of these, containing one per cent. of
+corrosive sublimate, is put on the market in cakes weighing about
+sixteen hundred grains, and each cake, therefore, contains sixteen
+grains of the drug--a rather large quantity, perhaps, when it is
+remembered that four grains is a fatal dose. Fortunately, however, for
+the prevention of accidents, but unfortunately for the therapeutic
+value of the soap, a decomposition of the sublimate occurs as soon as
+it is incorporated in the soap mass, by which an insoluble mercurial
+soap is formed. This change takes place independently of the alkali
+used in the soap; in fact, as mentioned above, a well-made soap
+contains no appreciable amount of free alkali, but is due to the
+action of the fat acids. Corrosive sublimate is _incompatible_ with
+any ordinary soap mass, and this incompatibility includes not only
+other soluble mercurial salts, but also almost all the mineral
+antiseptics, such as zinc chloride, copper sulphate, iron salts. Some
+of the preparations of arsenic may, however, be incorporated with soap
+without decomposition.
+
+Such being the chemical facts, we must admit that no reliance can be
+placed in corrosive sublimate soaps as germicide agents. It must not
+be supposed that this incompatibility interferes with the use of these
+soaps for general therapeutic purposes. It is only the specific
+germicide value which is destroyed. Since the fats used in soap
+manufacture yield oleic acid, we will have a certain amount of
+mercuric oleates formed together with stearate and other salts, and
+for purposes of inunction these salts might be efficient. Still the
+physician would prefer, doubtless, to use the specially prepared
+mercurial.
+
+In producing, therefore, a disinfecting soap, being debarred from
+using the metallic germicides, we are fortunate in the possession of a
+number of efficient agents, organic in character, which may be used
+without interference in soaps.
+
+Among these are thymol, naphthol, oil of eucalyptus, carbolates, and
+salicylates. There is no chemical incompatibility of these with soap,
+and as they are somewhat less active, weight for weight, than
+corrosive sublimate, they are capable of use in larger quantities with
+less danger, and can thus be made equally efficacious.
+
+It is in this direction, therefore, that we must look for the
+production of a safe and reliable antiseptic soap.
+
+There is not much exact knowledge as to the usefulness of such
+additions to soap as borax and glycerin. They are frequently added,
+and highly spoken of in advertisements. Borax is a mild alkaline body,
+and as a detergent is probably equivalent to a slight excess of
+caustic soda. Glycerin, although originally considered an emollient,
+probably on account of its source and physical properties, is in
+reality, to some skins at least, a slight irritant. It is, in fact, an
+alcohol, not a fat. It does not pre-exist in fats, but is formed when
+the fat is decomposed by alkali or steam.
+
+In ordinary cases, soap owes its detergent effect to a decomposition
+which occurs when it is put in water.
+
+A perfectly neutral soap, that is, one which contains the exact
+proportion of alkali and fat acid, will, when placed in cold water,
+decompose into two portions, one containing an excess of the acid, the
+other an excess of alkali. The latter dissolves, and gives a slightly
+alkaline solution; the former precipitates, and gives the peculiar
+turbidity constituting "suds." These reactions must be kept in mind in
+determining the effect of the addition of any special substance to the
+soap.--_The Polyclinic._
+
+       *       *       *       *       *
+
+
+
+
+OPTICAL ERRORS AND HUMAN MISTAKES.[1]
+
+  [Footnote 1: Read before the American Association, Buffalo,
+  August, 1886.]
+
+By ERNST GUNDLACH.
+
+
+I wish to call attention to a few mistakes that are quite commonly
+made by microscopists and writers in stating the result of their
+optical tests of microscope objectives.
+
+If the image of an object as seen in the microscope appears to be
+unusually distorted and indistinct toward the edge of the field, and
+satisfactory definition is limited to a small portion of the center,
+the cause is often attributed to the spherical aberration of the
+objective, while really this phenomenon has nothing to do with that
+optical defect of the objective, if any exists, but is caused by a
+lack of optical symmetry. If a perfectly symmetrical microscope
+objective could be constructed, then, with any good eye-piece, it
+would make no difference to the definition of the object were it
+placed either in the center or at the edge of the field, even if the
+objective had considerable spherical aberration. But, unfortunately,
+our most symmetrical objectives, the low powers, leave much to be
+desired in this respect, while our wide angle, high powers are very
+far from symmetrical perfection.
+
+There are two causes of this defect in the latter objectives, one
+being the extreme wideness of their angular apertures, and the other
+the great difference in the distances of the object and the image from
+the optical center of the objectives.
+
+Another mistake is often made in regard to the cause of certain
+prismatic colors that are sometimes, in a striking degree, produced by
+otherwise good objectives. According to the nature of these colors,
+whether yellow or blue, green or indigo, they are generally regarded
+as evidences of either chromatic over or under correction of the
+objective. Of course the presence of either of these defects is
+certainly and correctly indicated by the appearance of one or the
+other of the colors, under certain circumstances; but the simple
+visibility of prismatic color is by no means a reliable indication of
+over or under correction of color, and, indeed, to the honor of our
+opticians, it may be stated that very few objectives are made that
+cannot justly be called achromatic in the general sense of the term.
+By far the most common causes of prismatic color, in otherwise
+carefully constructed objectives, are the so-called chromatic
+aberrations of second or higher order. Every achromatic lens which is,
+as it should be, at its best at about two-thirds of its aperture, is
+inside of this ring or zone, toward the center slightly under and
+outside, toward the edge, slightly over corrected. This defect is the
+greater, the less the difference of the dispersive powers of the two
+glasses used in the construction of the lens, for a given proportion
+of their refractive indexes, and therefore the degree of visibility of
+the colors of the aberrations of the second order depends greatly on
+the nature of the glass employed in the construction of the lens.
+
+This defect may be corrected by a suitable combination of two or more
+lenses, though not without again having similarly, as in the
+correction of the first color, some faint remnants of color, the
+aberrations of third or still higher order. But even the correction of
+the third or still higher order may, if the angular aperture is very
+wide, leave quite visible and disturbing remnants of color.
+
+Another and not uncommon explanation of the cause of this unwelcome
+color, though not so serious and damaging a charge to the maker of the
+objectives, is its attribution to the so-called "secondary spectrum."
+This error, like that previously mentioned, is certainly indicated by
+the appearance of certain colors under certain conditions, but being,
+as a rule, one of the least defects of even our best objectives in
+most cases, it is probably not the true source of the disturbance.
+
+The secondary spectrum is very commonly confounded with the chromatic
+aberration of higher order. While the latter is produced by
+imperfections in the form of the lens, the former is due to an
+imperfection of the optical qualities of the material from which the
+lens is constructed, the crown and flint glass.
+
+A glass prism of any angle will project upon a white surface a
+spectrum of any length, according to the arrangement of the light
+source, the screen, and the prism. So with two prisms of the same kind
+of glass, but of different angles, two spectra can be produced of
+exactly equal length, so that if one is brought over the other, with
+the corresponding colors in line, they will appear as one spectrum.
+But if one of the prisms is made of crown and the other of flint
+glass, then their spectra cannot be arranged so that all their
+corresponding colors would be in line, for the proportional distances
+of the different colors differ in the two spectra. If two colors of
+the spectra are, by suitable arrangement, brought exactly in line,
+then the others will be out. The two spectra do not coincide, and the
+result, if an achromatic lens be made of these glasses, must be a
+remnant of color which cannot be neutralized. This remnant is the
+secondary spectrum.
+
+Although this peculiar disharmony in the dispersive powers of the two
+glasses, crown and flint, was discovered almost immediately after
+achromatism was invented, it was only recently that the first
+successful attempts were made to produce different glasses, which,
+possessing the other requirements for achromatic objectives, would
+produce coincident spectra, or nearer so than the ordinary crown and
+flint glass do. It was about twelve years ago, if my memory serves me,
+when I learned that a well-known English firm, engaged in the
+manufacture of optical glass, had brought out some new glass possessed
+of the desired qualities, and a little later I received a circular
+describing the glass. But at the same time I learned that the new
+glass was very soft and difficult to polish, and also that it had to
+be protected from the atmosphere, and further, that an English
+optician had failed to construct an improved telescope objective from
+it. I had ordered some samples of the glass, but never received any.
+
+A few months ago, news from Europe reached this country that another
+and seemingly more successful attempt had been made to produce glass
+that would leave no secondary spectrum, and that Dr. Zeiss, the famous
+Jena optician, had constructed some new improved objectives from it.
+But the somewhat meager description of these objectives, as given by
+an English microscopist, did not seem fit to excite much enthusiasm
+here as to their superiority over what had already been done in this
+country. Besides this, the report said that the new objectives were
+five system, and also that extra eye-pieces had to be used with them.
+I confess I am much inclined to attribute the optical improvement,
+which, according to Dr. Abbe's own remark, is very little, more to the
+fact that the objectives are five system than to the new glass used in
+their construction.
+
+After a close study of a descriptive list of the new glass, received a
+week or two ago from the manufacturers, I find, to my great regret,
+that this new glass seems to suffer from a similar weakness to that
+made by the English firm twelve years ago; as all the numbers of the
+list pointed out by the makers as having a greatly reduced secondary
+spectrum are accompanied with the special remark "to be protected."
+Furthermore, from a comparison of the dispersive and refractive powers
+of these glasses, as given in the list, I find that objectives
+constructed from them will leave so great aberrations of higher order,
+both spherical and chromatic, that the gain by the reduction of the
+secondary spectrum would be greatly overbalanced.
+
+In conclusion, I wish to say that while I would beware of
+underestimating the great scientific and practical value of the
+endeavor of the new German glass makers to produce improved optical
+glass, and the great benefit accruing to opticians and all others
+interested in the use of optical instruments, I think it wise not to
+overestimate the real value of the defects of the common crown and
+flint glass, which I have sought to explain in this paper. And, for
+myself, I prefer to fight the more serious defects first, and when its
+time has come I will see what can be done with the secondary spectrum.
+
+       *       *       *       *       *
+
+
+
+
+PROBABLE ISOLATION OF FLUORINE. DECOMPOSITION OF HYDROFLUORIC ACID
+BY AN ELECTRIC CURRENT.
+
+By M.H. MOISSAN.
+
+
+In a former memoir[1] we showed that it was possible to decompose
+anhydrous hydrofluoric acid by the action of an electric current. At
+the negative pole hydrogen collects; at the positive pole a gaseous
+body is disengaged, having novel properties. The experiment was
+performed in a platinum U tube, closed by stoppers of fluorite, and
+having at the upper part of each branch a small delivery tube, also of
+platinum. Through the stopper passes a platinum rod, which acts as
+electrode. The metal employed for the positive pole is an alloy
+containing 10 per cent. of iridium.
+
+  [Footnote 1: _Comptes Rendus_, vol. cii., p. 1543, and _Chemical
+  News_, vol. liv., p. 36.]
+
+To obtain pure anhydrous hydrofluoric acid, we begin by preparing
+fluorhydrate of fluoride of potassium, taking all the precautions
+pointed out by M. Fremy. When the salt is obtained pure, it is dried
+on a water bath at 100°, and the platinum capsule containing it is
+then placed in a vacuum in the presence of concentrated sulphuric
+acid, and two or three sticks of potash fused in a silver crucible.
+The acid and potash are renewed every morning for a fortnight, and the
+vacuum is kept at 2 cm. of mercury. Care must be taken during this
+desiccation to pulverize the salt every day in an iron mortar, so as
+to renew the surface. When the fluorhydrate contains no more water it
+falls to powder, and is then fit to serve for the preparation of
+fluoric acid; the fluorhydrate of fluoride of potassium, if well
+prepared, is much less deliquescent than the fluoride.
+
+When the fluoride is quite dry, it is quickly introduced into a
+platinum alembic, which has just been dried by heating it to redness.
+The whole is kept at a gentle temperature for an hour or an hour and a
+half, so as to allow the decomposition to commence very slowly; the
+first portions of acid which come over are rejected as they carry with
+them traces of water remaining in the salt. The platinum receiver is
+then attached, and the heat increased, allowing the decomposition to
+proceed with a certain degree of slowness. The receiver is then
+surrounded with a mixture of ice and salt, and from this moment all
+the hydrofluoric acid is condensed as a limpid liquid, boiling at
+19.5°, very hygroscopic, and, as is well known, giving abundant fumes
+in presence of the atmospheric moisture.
+
+During this operation the platinum U tube, dried with the greatest
+care, has been fixed with a cork in a cylindrical glass vessel
+surrounded with chloride of methyl. Up to the moment of introducing
+the hydrofluoric acid, the leading tubes are attached to drying tubes
+containing fused caustic potash. To introduce the hydrochloric acid
+into the apparatus, it may be absorbed through one of the lateral
+tubes in the receiver in which it is condensed.
+
+In some experiments we have directly condensed the hydrofluoric acid
+in the U tube surrounded with chloride of methyl; but in this case
+care must be taken that the tubes are not clogged up by small
+quantities of fluoride carried over, which would infallibly lead to an
+explosion and projections, which are always dangerous with so
+corrosive a liquid.
+
+When we have introduced in advance in the small platinum apparatus a
+determined amount of hydrofluoric acid cooled with chloride of methyl,
+in tranquil ebullition at a temperature of -23°, the current of 20
+cells of Bunsen large size, arranged in series, is passed through by
+means of the electrodes. An amperemeter in the circuit admits of the
+intensity of the current being observed.
+
+If the hydrofluoric acid contains a small quantity of water, either by
+accident or design, there is always disengaged at the positive pole
+ozone, which has no action on crystallized silicium. In proportion as
+the water contained in the acid is thus decomposed, it is seen by the
+amperemeter that the conductivity of the liquid rapidly decreases.
+With absolutely anhydrous hydrofluoric acid the current will no longer
+pass. In many of our experiments we have succeeded in obtaining an
+acid so anhydrous that a current of 25 amperes was entirely arrested.
+
+To render the liquid conducting, we have added before each experiment
+a small quantity of dried and fused fluorhydrate of fluoride of
+potassium. In this case, decomposition proceeds in a continuous
+manner; we obtain at the negative pole hydrogen, and at the positive
+pole a regular disengagement of a colorless gas in which crystallized
+silicium in the cold burns with great brilliancy, becoming fluoride of
+silicium. This latter gas has been collected over mercury, and
+accurately characterized.
+
+Deville's adamantine boron burns in the same manner, but with more
+difficulty, becoming fluoride or boron. The small quantity of carbon
+and aluminum which it contains impedes the combination. Arsenic and
+antimony in powder combine with this gaseous body with incandescence.
+Sulphur takes fire in it, and iodine combines with a pale flame,
+losing its color. We have already remarked that it decomposes cold
+water, producing ozone and hydrofluoric acid.
+
+The metals are attacked with much less energy. This is due, we think,
+to the small quantity of metallic fluoride formed preventing the
+action being very deep. Iron and manganese in powder, slightly heated,
+burn with sparks. Organic bodies are violently attacked. A piece of
+cork placed near the end of the platinum tube, where the gas is
+evolved, immediately carbonizes and inflames. Alcohol, ether, benzol,
+spirit of turpentine, and petroleum take fire on contact.
+
+The gas evolved at the negative pole is hydrogen, burning with a pale
+flame, and producing none of these reactions.
+
+When the experiment has lasted several hours, and there is not enough
+hydrofluoric acid left at the bottom of the tube to separate the two
+gases, they recombine in the apparatus in the cold, with violent
+detonation.
+
+We have satisfied ourselves, by direct experiment, that a mixture of
+ozone and hydrofluoric acid produces none of the reactions described
+above.
+
+It is the same with gaseous hydrofluoric acid. Finally we may add that
+the hydrofluoric acid employed, as well as the hydrofluorate of
+fluoride, were absolutely free from chlorine.
+
+The gas obtained in our experiments is therefore either fluorine or a
+perfluoride of hydrogen.
+
+New experiments are necessary to settle this last point. We hope soon
+to lay the results before the Academy.--_Comptes Mendus_, vol. ciii.,
+p. 202, July 19, 1886; _Chem. News._
+
+       *       *       *       *       *
+
+
+
+
+COHESION AND COHESION FIGURES.[1]
+
+  [Footnote 1: Notes from a lecture given to the Halifax Scientific
+  Society, July 19, 1886.]
+
+By WILLIAM ACKROYD, F.I.C.
+
+
+_1. A Law of Solubility._
+
+It is customary to regard cohesion as the force which binds together
+molecules of the same substance, and in virtue of which the particles
+of solids and liquids are kept together, and also to speak of the
+attraction exerted between particles of two different bodies as
+adhesion. The distinction between cohesion and adhesion is a
+conventional one. The similarity, if not identity, of the two forces
+is demonstrated by the fact that while cohesion is exerted between
+particles of the _same_ body, adhesion is exerted with most force
+between particles of _allied_ bodies. Generally speaking, organic
+bodies require organic solvents; inorganic bodies, inorganic solvents.
+For example, common salt is highly soluble in water, but not in ether,
+and many fats are soluble in ether, but not in water. So many cases
+like these will suggest themselves to the chemist that I am justified
+in making the following generalization: _A body will dissolve in a
+solvent to which it is allied more readily than in one to which it in
+highly dissimilar._ Exceptions to the law undoubtedly exist, but none
+so striking as the following in support of it, viz., that the metal
+mercury is the only known true solvent for many metals at the normal
+temperature.
+
+
+_2. Its Connection with Mendeleeff's Periodic Law._
+
+From this standpoint the whole subject of solution is deserving of
+fresh attention, as it appears highly probable that, just as Prof.
+Carnelley has shown by the use of my meta-chromatic scale, the colors
+of chemical compounds come under definite laws, which he has
+discovered and formulated in connection with Mendeleeff and Newlaud's
+periodic law,[2] so, likewise, may the solubility of an allied group
+of compounds, in regard to any given solvent under constant conditions
+of temperature, conform to similar laws; that, e.g., the chlorides
+of H, Na, Cu, and Ag, in Mendeleeff's Group I., may vary in their
+solubility in water from an extreme of high solubility in the case of
+hydrogen chloride to the opposite extreme of comparative insolubility
+in the case of silver chloride. In this natural series of compounds,
+hydrogen chloride is the body nearest akin to water, and silver
+chloride the most remote in kinship.
+
+  [Footnote 2: _Philosophical Magazine_, August, 1884.]
+
+
+_3. A Solidified Vortex Ring._
+
+It is in virtue of cohesion that a freely suspended drop of liquid
+assumes the spherical form. If such a sphere be dropped on to the
+surface of a liquid of higher specific gravity at rest, one obtains
+what is called the cohesion figure of the substance of the drop. A
+drop of oil, e.g., spreads out on the surface of water until it is a
+circular thin film of concentric rings of different degrees of
+thickness, each displaying the characteristic colors of thin plates.
+The tenuity of the film increases; its cohesion is overcome; lakelets
+are formed, and they merge into each other. The disintegrated portions
+of the film now thicken, the colors vanish, and only islets of oil
+remain. Some liquid drops of the same or higher sp. gr. than water do
+not spread out in this fashion, but descend below the surface of the
+liquid, and, in descending, assume a ring shape, which gradually
+spreads out and breaks up into lesser rings. Such figures have been
+termed submergence cohesion figures; they are vortex rings. I have
+solidified such vortex rings in their first stage of formation. If
+drops of melted sulphur, at a temperature above that of the viscous
+state, be let fall into water, the drops will be solidified in the
+effort to form the ring, and the circular button, thick in the rim and
+thin in the center, may be regarded as a solidified vortex ring of
+plastic sulphur.
+
+
+_4. That a Submergence Cohesion Figure is a Vortex Ring._
+
+It may be shown that the conditions of the formation of a submergence
+cohesion figure are those which exist in the formation of an aerial
+vortex. Those conditions in their greatest perfection are (1) a
+spherical envelope of a different nature from the medium in which the
+rings are produced; (2) a circular orifice opening into the medium;
+and (3) a percussive impact on the part of the sphere opposite the
+orifice. In the production of vortex rings of phosphorus pentoxide in
+the making of phosphoreted hydrogen, the spherical envelope is water,
+the orifice the portion of the bubble which opens into the air
+immediately it rises to the surface, and the impact is furnished by
+gravity. So, also, in the case of a submergence cohesion figure, the
+spherical envelope is the air surrounding the drop, the orifice the
+portion of it which first comes in contact with the liquid at rest;
+and here again the impact is due to gravity more directly than in the
+former case. These conditions are somewhat imperfectly copied in the
+ordinary vortex box, which is usually cubical in form, with a circular
+orifice in one side, and a covering of canvas on the opposite one,
+which is hit with the fist.
+
+       *       *       *       *       *
+
+[AMERICAN CHEMICAL JOURNAL.]
+
+
+
+
+THE DETERMINATION OF NITRIC ACID BY THE ABSORPTION OF NITRIC OXIDE
+IN A STANDARD SOLUTION OF PERMANGANATE OF POTASSIUM.
+
+By H.N. MORSE and A.F. LINN.
+
+
+The method which we propose consists in the conversion of the nitric
+acid into nitric oxide; the absorption of the latter in a measured,
+but excessive, quantity of a standard solution of permanganate of
+potassium; and the subsequent determination of the excess of the
+permanganate by means of a standard solution of oxalic acid or
+sulphate of manganese.
+
+
+THE APPARATUS.
+
+A is an apparatus for the generation of carbon dioxide free from air,
+which will be explained hereafter.
+
+B is a flask, having a capacity of 125 or 150 c.c., in which the
+nitrate is decomposed in the usual manner by means of ferrous chloride
+and hydrochloric acid.
+
+C is a small tube for the condensation of the aqueous hydrochloric
+acid which distills over from B.
+
+D is a Geissler bulb, containing a concentrated solution of potassium
+carbonate, to arrest any acid vapors coming from C.
+
+E, E are two pieces of ordinary combustion tubing, having a length of
+about 650 or 700 mm., in which is placed the permanganate solution
+employed for the absorption of the nitric oxide. Their open ends are
+provided with lips in order to facilitate the pouring of liquids from
+them, care being taken not to so distort the ends that rubber stoppers
+cannot be made to fit them tightly. They are placed in a nearly
+horizontal position in order to diminish the pressure required to
+force the gases through the apparatus and thus lessen the danger of
+leakage through the rubber joints.
+
+_a_ is a tube through which the ferrous chloride and hydrochloric acid
+are introduced into B, as in the method of Tiemann-Schulze.
+
+_b_ serves for the introduction of carbon dioxide to expel the air
+before the decomposition of the nitrate, and the nitric oxide
+afterward.
+
+_c_ is an unbroken tube ending at the lower surface of the stopper in
+B, and at the bottom of C.
+
+The rubber joint, _d_, is furnished with a Mohr and also a screw pinch
+cock. The joints, _e_ and _f_, are furnished with Mohr pinch cocks.
+The rubber tubing upon these should be of the best quality, and must
+be carefully tied.
+
+[Illustration: DETERMINATION OF NITRIC ACID.]
+
+
+THE SOLUTIONS.
+
+In consequence of the large volume of the permanganate solution
+required for the complete absorption of the nitric oxide, we have
+found it advantageous to use three solutions instead of two.
+
+1. A solution of permanganate such that one c.c. is equivalent to
+about fifteen milligrammes of nitrate of potassium, according to the
+reaction:
+
+  KMnO_{4} + NO = KNO_{3} + MnO_{2}.
+
+This solution is employed for the absorption of the nitric oxide. Its
+strength need not be exactly known. There is no objection to a more
+concentrated solution, except that which pertains to all strong
+standard solutions, namely, that a small error in measurement would
+then give a larger error in the results. 100 c.c. of this solution are
+required for each determination, and the measurement is always made in
+one and the same 100 c.c. measuring flask, which, if necessary, should
+be labeled to distinguish it from that used for solution No. 2.
+
+2. A solution of oxalic acid which is very slightly stronger than that
+of the permanganate just described--that is, a solution such that one
+c.c. of it will somewhat more than decompose one c.c. of the
+permanganate, according to the reaction:
+
+  2KMnO_{4} + 3H_{2}SO_{4} + 5C_{2}H_{2}O_{4}.2H_{2}O =
+  K_{2}SO_{4} + 2MnSO_{4} + 18H_{2}O + 10CO_{2}.
+
+The exact strength of this solution need not be known, since we only
+require the difference in value between it and solution No. 1, which
+is determined by means of solution No. 3. 100 c.c. of this solution
+are also required for each determination, and the measurement, as in
+the preceding case, is always made in the same 100 c.c. measuring
+flask.
+
+3. A dilute, carefully standardized solution of permanganate of
+potassium.
+
+The method of using these solutions is as follows: 100 c.c. of No. 1
+and No. 2 are measured off (each solution in its own measuring flask),
+brought together in a covered beaker glass, and acidified with dilute
+sulphuric acid. The excess of oxalic acid is then determined by means
+of solution No. 3.
+
+When it is desired to make a determination of nitric acid, 100 c.c. of
+solution No. 1 are measured off, and as much of it as may be
+convenient is poured into the tubes, E, E, together with about a
+gramme of zinc sulphate for each tube, which substance appears to
+considerably facilitate the absorption of the nitric oxide by the
+permanganate. When the operation is over, the contents of E, E are
+poured into a beaker glass. 100 c.c. of solution No. 2 are then
+measured off, and a portion, together with a little sulphuric acid,
+poured into E, E, to dissolve the oxide of manganese which has
+separated during the absorption of the nitric oxide. The oxide having
+been dissolved, the liquid in E, E, and the rinsings of the tubes,
+also the residues of permanganate and oxalic acid left in the
+measuring flasks, and the rinsings from these, are all brought
+together in the same beaker glass. Finally, the amount of solution
+No. 3 required to decompose the excess of oxalic acid is determined.
+If we subtract from the amount thus found the quantity of permanganate
+required to equalize solutions Nos. 1 and 2 (previously ascertained),
+we shall have the amount of permanganate actually reduced by the
+nitric oxide, according to the reaction:
+
+  6KMnO_{4} + 10NO = 3K_{2}O + 6MnO + 5N_{2}O_{5};
+
+in other words, on the basis that one molecule of potassium
+permanganate will oxidize one and two-thirds molecules of nitric
+oxide:
+
+  (KMnO_{4} = 1-2/3 NO).
+
+The method of using the apparatus is simple. The nitrate is placed in
+B, and the joints made tight, except that at _f_, which is left open.
+A current of carbon dioxide is passed through the apparatus until all
+of the air has been displaced. Connection is then made at _f_, and
+soon afterward the current of carbon dioxide is shut off at _d_.
+
+The flask, B, is now heated as long as may be necessary in order to
+produce, on cooling, the diminished pressure required for the
+introduction of the ferrous chloride and hydrochloric acid. Before
+removing the flame, the joint at _f_ is closed to prevent the return
+of the permanganate solution.
+
+As soon as the flask, B, has become sufficiently cool, the ferrous
+chloride and hydrochloric acid are introduced through the tube, _a_
+(which has been full of water from the first), in the same manner and
+quantities as in the well-known Tiemann-Schulze method.
+
+The pinch cock at _d_ is then opened, and the apparatus allowed to
+fill with carbon dioxide. When the pressure has become sufficient to
+force the gas through the solution of permanganate, the pinch cock at
+_f_ is removed. It should be opened only slightly and with great
+caution at first, unless one is certain that the pressure is
+sufficient. If the pressure is insufficient, the fact will be made
+apparent by a rise of the permanganate in the small internal tube.
+
+The flow of carbon dioxide is now reduced to a very slow current, or
+entirely cut off. The contents of B are slowly heated, until the
+decomposition of the nitrate is complete and the greater part of the
+nitric oxide has been expelled, when the apparatus is again closed at
+_f_ and _d_, and allowed to cool. The tube, _a_, is then washed out,
+by the introduction through it into B of a few cubic centimeters of
+strong hydrochloric acid.
+
+The process of filling the apparatus with carbon dioxide, and of
+heating the contents of B, is repeated. When it becomes apparent, from
+the light color of the liquid in B, that all of the nitric oxide has
+been expelled from it, the current of carbon dioxide is increased and
+the heating discontinued. Care must be taken, however, not to admit
+too strong a current of carbon dioxide, lest some of the nitric oxide
+should be forced unabsorbed through the permanganate solution. It is
+also necessary, for the same reason, to avoid too rapid heating during
+the decomposition of the nitrate.
+
+When all of the nitric oxide has been forced into the solution of
+permanganate, the determination is made in the manner already
+described.
+
+To test the method, nine determinations were made with quantities of
+pure nitrate of potassium varying from 100 to 200 milligrammes. The
+maximum difference between the volumes of permanganate actually used
+and those calculated was 0.05 c.c., while the main difference was
+0.036 c.c. The measurements of the permanganate were made from a
+burette which had been carefully calibrated. We also made a number of
+determinations, using a solution of manganous sulphate in the place of
+the oxalic acid. The advantage of this method lies in the fact that it
+is not necessary to dissolve the oxide which is precipitated upon the
+glass within the tubes, E, E, since, in the presence of an excess of
+permanganate, the reduction by nitric oxide extends only to the
+formation of MnO_{2}; also in the fact that the solution of manganous
+sulphate is more stable than that of oxalic acid. A solution of the
+sulphate having been once carefully standardized, can be used for a
+long time to determine the value of permanganate solutions.
+
+The details of the method are as follows: A solution of manganous
+sulphate slightly stronger than No. 1 is prepared.
+
+The difference between 100 c.c. of it and 100 c.c. of No. 1 is
+ascertained, according to the method of Volhard, by means of solution
+No. 3.
+
+The contents of E, E, together with the rinsings from the tubes, are
+poured into a capacious flask. 100 c.c. of the manganous sulphate and
+a few drops of nitric acid are then added, and the whole boiled.
+Finally, the excess of manganous sulphate is determined, in the manner
+described by Volhard, by means of solution No. 3. Subtracting from the
+total amount of permanganate thus used the quantity required to
+equalize the 100 c.c. of solution No. 1 and the 100 c.c. of the
+manganous sulphate, we shall have the quantity of permanganate reduced
+by the nitric oxide.
+
+It must, however, be remembered that the value of solution No. 3 is
+now to be calculated on the basis of the equation KMnO_{2} + NO =
+KNO_{3} + MnO_{2}. One molecule of permanganate equals one molecule of
+nitric oxide when manganous sulphate is used, since no part of the
+permanganate employed in this method is reduced below the superoxide
+condition. In other words, solution No. 3 now represents only
+three-fifths as much nitric acid as it does when oxalic acid is used.
+
+The results obtained by this method were moderately satisfactory, but
+not quite so exact as those obtained when oxalic acid was used. A
+series of four determinations gave differences, between the volumes of
+permanganate calculated and used, of 0.05 to 0.15 c.c.
+
+The principal objection to the method lies in the difficulty of
+determining, in the presence of the brown oxide of manganese, the
+exact point at which the oxidation is complete.
+
+The carbon dioxide generator, A, was devised by us to take the place
+of the ordinary generators, in which marble is used. We have found
+that a submersion of twenty hours in boiling water does not suffice to
+completely remove the air which, as is well known, is contained in
+ordinary marble; hence some other substance must be employed as a
+source of the gas. In the apparatus which we are about to describe,
+the acid carbonate of sodium is used.
+
+It consists of a long, narrow cylinder (450 x 60 mm.); a tightly
+fitting rubber stopper, through which three tubes pass, as shown in
+the figure; a small cylinder, F, containing mercury; and a sulphuric
+acid reservoir, G.
+
+The tube, _g_, is drawn out to a fine point at the end and curved, so
+that the acid which is delivered into A falls upon and runs down the
+outside of the tube. The tube, h, dips under the mercury in F. G and
+_g_ are connected by means of a long piece of rubber tubing which is
+supplied with a screw pinch cock.
+
+The apparatus is made to give any required pressure by raising or
+lowering G and F; but the elevation of G, as compared with that of F,
+should always be such that the gas will force its way through h rather
+than g. The upper part of the cylinder, F, is filled with cotton wool
+to prevent loss of mercury by spattering.
+
+The material placed in A consists of a saturated solution of acid
+carbonate of sodium, to which an excess of the solid salt has been
+added. The sulphuric acid is the ordinary dilute. The apparatus, if
+properly regulated, serves its purpose very well. The principal
+precaution to be observed in using it is to avoid a too sudden
+relieving of the pressure, which would, of course, result in the
+introduction of an unnecessarily large quantity of sulphuric acid into
+A.
+
+       *       *       *       *       *
+
+
+
+
+WATER OF CRYSTALLIZATION.
+
+By W.W.J. NICOL, M.A., D.Sc.
+
+
+When a hydrated salt is dissolved, does it retain its water of
+crystallization, or does this latter cease to be distinguishable from
+the solvent water? Both views have found advocates among chemists who
+have looked at the question of solution, and both have been supported
+by arguments more or less to the point. But among the possible means
+of solving this question there is one which has entirely escaped the
+notice of those interested in the subject. And those who hold that
+water of crystallization exists in solution have been entirely
+oblivious of the fact that, while they are ready to accept the results
+of the modern science of thermo-chemistry, and to employ them to
+support their views on hydration, yet these very results, if correct,
+prove without a shadow of a doubt that water of crystallization does
+not exist in solution.
+
+The proof is so clear and self-evident when once one's attention is
+directed to it, that, though I intend to develop it more fully on
+another occasion, I feel that it is better to publish an outline of it
+at once.
+
+Thomsen has found that the heat of neutralization of the soluble bases
+of the alkalies and alkaline earths with sulphuric acid has a mean
+value of 31.150 c. within very narrow limits. When hydrochloric or
+nitric acid is employed, the value is 27.640 c., also within very
+narrow limits. Now, this agreement of the six bases in their behavior
+with sulphuric acid, much more of the seven bases with both HNO_{3}
+and HCl, is so close that it cannot be regarded as accidental, but, in
+the words of Meyer, the heat of formation of a salt in aqueous
+solution is a quantity made up of two parts, one a constant for the
+base, the other for the acid. But of the twenty salts thus formed,
+some are anhydrous in the solid state, others have water of
+crystallization, up to ten molecules in the case of Na_{2}SO_{4}. If
+water of crystallization exists in solution, it will be necessary to
+suppose that this agreement is accidental, which is absurd, as a
+glance at the probabilities will show. Thomsen himself expressly
+states that he regards the dissolved state as one in which the
+conditions are comparable for all substances; this would be impossible
+if water of crystallization were present.
+
+A still stronger proof is afforded by the "_avidity_" of Thomsen or
+the "_affinity_" of Ostwald; both have worked on the subject, taking
+no account of water of crystallization, and the results, e.g., for
+H_{2}SO_{4} and HCl with NaHO, where water of crystallization _may_
+come in, are entirely confirmed by Ostwald's results on inversion and
+etherification, where there can be no water of crystallization.
+
+The proof is complete, water of crystallization cannot be attached to
+the salt in solution, or if it is, no heat is evolved on union more
+than with solvent water. The alternative is to suppose that the whole
+of the above thermo-chemical results are coincidences.
+
+       *       *       *       *       *
+
+
+
+
+ALPINE FLOWERS IN THE PYRENEES.
+
+
+Bagneres De Luchon, in the department of the Haute Garonne, is a gay
+town of some 5,000 inhabitants. A friend told me that he once suffered
+so much from the heat there in June, that he determined never to go to
+the Pyrenees again. We were there the second week in June, and we
+suffered more from rain and cold, and were very glad of a fire in the
+evening.
+
+Except to the south, in the direction of the Porte de Venasque, one of
+the chief mule passes into Spain during summer, where there are fine
+snow-capped mountains, the scenery from the town is not grand, but it
+is within easy reach of the wildest parts of the Pyrenees.
+
+It is the nearest town to the Maladetta, their highest point, in which
+the Garonne rises, and among whose rocks is one of the last
+strongholds of the ibex or bouquetin, the "wild goat" mentioned by
+Homer. Eagles and vultures are to be seen sailing about the sky near
+Luchon nearly every day, and bears, which in the Pyrenees are neither
+mythical nor formidable, descend to within a few miles of the town
+after wild strawberries, which abound there.
+
+We heard of two female peasants lately gathering wild strawberries who
+were suddenly confronted with competitors for the spoil in the shape
+of a she bear and two cubs. It was doubtful whether man or beast was
+the more surprised. The cubs began to growl, but their dam gave both
+of them a box on the ears for their bad manners, and led them away. As
+for flowers, the neighborhood of Luchon has the reputation, perhaps
+not undeserved, of being the most flowery part of the Pyrenees.
+
+We went the usual expeditions from the town, in spite of the weather,
+and I will try to remember what plants we noticed in each of them. The
+first trip was to the Vallee du Lys. In spite of the spelling, the
+name suggests lilies of the valley, but we are told that lys is an old
+word meaning water, and that the valley took its name from the number
+of cataracts, not from lilies, there.
+
+However this may be, a lily grows there in great profusion, and was
+just coming into flower toward the middle of June. It is the Lis de
+St. Bruno (Anthericum liliastrum), a plant worthy of giving its name
+to a valley of which it is a characteristic feature. Still more
+conspicuous at the time when we were there were the Narcissus
+poeticus, abundant all round Luchon, but already past in the low
+meadows near the town, but higher up, at an elevation of about 4,000
+ft., it was quite at its best, and whitened the ground over many
+acres.
+
+I looked about for varieties, but failed to detect any special
+character by which it could be referred to any of the varietal names
+given in catalogues, and concluded that it was N. poeticus pure and
+simple. Pulmonarias were abundant along the road, as also in the whole
+region of the Pyrenees, the character of the leaves varying greatly,
+some being spotless, some full of irregular white patches, others with
+well defined round spots. They varied, too, from broad heart-shaped to
+narrow lanceolate, and I soon concluded that it was hopeless to
+attempt any division of the class founded upon the leaves.
+
+Besides the beautiful flowers of Scabious mentioned before, a new
+feature in the meadows here was the abundance of Astrantia major. A
+pure white Hesperis matronalis was also common, but I saw no purple
+forms of it. Geranium phæum also grew everywhere in the fields, the
+color of the flower varying a good deal. Hepaticas were not so common
+by the roadside here as at Eaux Bonnes, but are generally distributed.
+Many of them have their leaves beautifully marbled, and I selected and
+brought away a few of the best, in hopes that they may keep this
+character. I was struck everywhere by the one-crowned appearance of
+the Hepaticas, as if in their second year from seed.
+
+On the mountains, where they were still in flower, I did not find the
+colors mixed, but on one mountain they would be all white, on another
+all blue. I do not recollect to have seen any pink. Meconopsis
+cambrica is common in the Pyrenees. I observe that in Grenier's
+"French Flora" the color of the flower is given as "jaune orange," but
+I never saw it either in England or in France with orange flowers till
+I saw it covering a bank by the side of the road to the Vallee du Lys.
+I was too much struck by it to delay securing a plant or two, which
+was lucky, for when we returned every flower had been gathered by some
+rival admirers.
+
+Another expedition from Luchon is to the Lac d'Oo. This, too, is
+famous for flowers; but especially so is a high valley called Val
+d'Esquierry, 2,000 ft. or 3,000 ft. above the village d'Oo, at which
+the carriage road ends. Botanists call this the garden of the
+Pyrenees, and, of course, I was most anxious to see it.
+
+The landlord of our hotel was quite enthusiastic in his description of
+the treat in store for me, enumerating a long catalogue of colors, and
+indicating with his hand, palm downward, the height from the ground at
+which I was to expect to see each color. I was afterward told that he
+had never been to the famous valley, being by no means addicted to
+climbing mountains.
+
+During the first part of the drive from Luchon we saw hanging from the
+rocks by the roadside large masses of Saponaria ocymoides, varying
+much in the shade of color of the flowers. This is a plant which I
+find it better to grow from cuttings than from seed. The best shades
+of color are in this way preserved, and the plants are more flowery
+and less straggling. As we got near the end of the carriage road, the
+meadows became more crowded with flowers known in England only in
+gardens.
+
+Besides such plants as Geranium pyrenaicum growing everywhere on the
+banks, the fields were full of a light purple geranium--I think
+sylvaticum. Here, too, I noticed Meconopsis cambrica with orange
+flowers. Narcissus poeticus was also there, and so were some splendid
+thistles, large and rich in color. But the most remarkable part of the
+coloring in the meadows was produced by different shades of Viola
+cornuta carpeting the ground. We noticed this plant in many parts of
+the Pyrenees, but here especially.
+
+From the end of the road I started with a guide for the promised
+garden of the Val d'Esquierry. By the side of the steep and winding
+path I noticed Ramondia pyrenaica--the only place I saw it in the
+Luchon district. Other notable plants were a quantity of Anemone
+alpina of dwarf growth and very large flowers, covering a green knoll
+near a stream. A little beyond, Aster alpinus was in flower, of a
+bright color, which I can never get it to show in gardens. These, with
+the exception of a few saxifrages and daffodils of the variety
+muticus, were about the last flowers I saw there.
+
+[Illustration: GROUP OF ALPINE FLOWERS]
+
+Promise of flowers there was in abundance. Aconites, I suppose
+napellus, and also that form of A. lycoctonum with the large leaves
+known as pyrenaicum, were just enough grown to recognize. The large
+white Asphodel, called by French botanists A. albus, but better known
+in gardens as A. ramosus, which grows everywhere in the Pyrenees, and
+the coarse shoots of Gentiana lutea were just showing.
+
+Further on the daffodils were only just putting their noses through
+the yellow dead grass, which the snow had hardly left and was again
+beginning to whiten, for the rain, which had been coming down in
+torrents ever since I left the carriage and had wet me through, had
+now changed to snow. Still I went on, in spite of the bitter cold,
+hoping that I should come to some hyperborean region where the flowers
+would be all bright; but my guide at last undeceived me, and convinced
+me that we were far too early, so we went down again, wiser and
+sadder, and I advise my friends who wish to see the Val d'Esquierry in
+its beauty not to visit it before July at the earliest.
+
+I have still one mountain walk to describe, a far more successful one,
+but it must be deferred till another week.--_C. Wolley Dod, in the
+Garden._
+
+       *       *       *       *       *
+
+
+Turtle shells may be softened by hot water, and if compressed in this
+state by screws in iron or brass moulds, may be bent into any shape,
+the moulds being then plunged into cold water.
+
+       *       *       *       *       *
+
+
+
+
+A CENTURY PLANT IN BLOOM.
+
+
+A huge agave, or century plant, is now blooming at Auburn, N.Y. A few
+days ago the great plant became tinged with a delicate yellowish-white
+color, as its 4,000 buds began to develop into the full-blown flowers,
+whose penetrating fragrance, not unlike that of the pond lily, now
+attracts swarms of bees and other insects. The plant was purchased in
+1837 by the owner, and was then twelve years old. For half a century
+the agave has lain around his greenhouses in company with several
+others, and no special care has been taken of it, except to protect it
+somehow in winter, that it might be fresh for the next summer's
+growth. The plant has always been a hardy specimen, and required
+little care. Its whole life, now speedily approaching a termination in
+the fulfillment of the end of its existence--flowering--has been a
+sluggish course. Its growth has been steady and its development
+gradual. Occasionally it has thrust out a spiked leaf until, in size,
+it became greater than its fellow plants and took on the likeness of
+an enormous cabbage which had been arrested in its development and
+failed to attain perfection. Early last April its appearance began to
+undergo a decided change. Its resemblance to a cabbage lessened, and
+it began to look like a giant asparagus plant. On April 12, the great
+fleshy leaves, massed together so as to impress the imprint of their
+spines upon one another, began to unfold, and a thick, succulent bud
+burst up amid the leaves. Slowly the stalk developed from the bud and
+assumed gigantic proportions. Green scales appeared in regular
+arrangement about the stalk, marking the points from which lateral
+branches were to spring. The thick stalk, tender and brittle at first
+as new asparagus, became tough and hard enough to resist a knife, and
+its surface assumed the gritty character of the leaves of the plant.
+The low roof of the hothouse became an obstruction to further growth,
+and had to be removed. Lateral limbs were, at a later period, thrust
+out in great numbers, each of them bearing small branches, as do
+strawberry plants, on which hang sprays of buds in bunches of from
+three to ten, making in all many hundreds, all waiting for the
+completion and blooming of the topmost buds. The inflorescence of the
+century plant is peculiar, and the appearance of flowers on the lower
+branches may be simultaneous with, or consecutive to, the blossoming
+on the upper limbs. With the appearance of the lateral outshoots the
+great aloe lost its likeness to asparagus, and at present bears
+resemblance to an immense candelabra. The plant is now fully matured,
+and has a height of twenty-seven feet. There are thirty-three branches
+on the main stem, and, by actual count, one of the lateral limbs was
+found to bear 273 perfect buds, some of whose green sepals have
+spread, revealing the yellowish-white petals and essential parts of
+the plant. The ample panicles crowded with curious blossoms are, as,
+indeed, the Greek name of the plant--agave--signifies, wonderful.
+
+There is a pathetic view to be taken of the great plant's present
+condition. For years it has been preparing to flower, and the shoot it
+has sent up is the dying effort. The blossoms carry in them the life
+of new plants, and the old plant dies in giving them birth. It is
+commonly supposed that this plant, the _Agave Americana_, or American
+aloe, blooms only at the end of 100 years, hence the common name
+century plant.
+
+Only two plants are on record among the floriculturists as having
+bloomed in New York State. Thirty years ago, a century plant, of which
+the Casey aloe was a slip, flowered in the greenhouses of the Van
+Rensselaer family at Albany. In 1869, a second plant blossomed at
+Rochester. At present, two aloes, one at Albany, the other at
+Brooklyn, are reported as giving evidences of approaching maturity.
+They are pronounced not American aloes, or century plants, but _Agave
+Virginica_, a plant of the same family commonly found in sterile soil
+from Virginia to Illinois and south, and blossoming much more
+frequently. In Mexico the century plant is turned to practical account
+and made a profitable investment to its owners. After the scape has
+reached its full growth it is hewn down, and the sap, which fills the
+hollow at its base, is ladled out and converted by fermentation into
+"agave wine," or "pulque," the favorite drink of the Mexicans. This
+pulque, or octli, has an acid resembling that of cider, and a very
+disagreeable odor, but the taste is cooling and refreshing. A brandy
+distilled from pulque is called "aquardiente," or "mexical." The
+plant, by tapping, can be made to yield a quart of sap daily. The
+fibers of the leaves when dried furnish a coarse thread known as Pita
+flax, and when green are used in Mexico as fodder for cattle. Razor
+strops or hones are also made from the leaves, which contain an
+abundance of silica and give rise to a very sharp edge on a knife
+applied with friction across the surface of the dried leaf.
+
+       *       *       *       *       *
+
+
+
+
+CREOSOTE A SPECIFIC FOR ERYSIPELAS.
+
+
+Time was when the advocate of a specific was laughed at by the
+scientific world, but since it is known that so many forms of disease
+are the direct result of some kind of germ life, it is no longer a
+misnomer to call a medicine which will certainly and always destroy
+the germ which produces so many forms of disease a specific.
+
+In the light of this definition, founded upon the experience of forty
+years' successful practice in treating this form of disease with
+creosote, the writer is prepared to indorse the heading of this
+article. Having used all the different remedies ordinarily prescribed,
+they have long since been laid aside, and this one used in all forms
+of the disease exclusively, and with uniform success.
+
+In 1863 it was the writer's fortune to spend several weeks in a
+military hospital in Memphis as a volunteer surgeon, under the
+direction of Dr. Lord. In conversation with him, the use of this
+article was mentioned, which appeared new to him, and a case was put
+under treatment with it, with such prompt favorable results as to
+elicit his hearty commendation, and, at his suggestion,
+Surgeon-General Hammond was informed of it.
+
+All injuries, of whatever kind, have been treated with dressings of
+this remedy, and where this has been done from the first to last, in
+no instance has there been an attack of erysipelas.
+
+The usual manner of application was in solution of six to twenty drops
+to the ounce of water, keeping the parts covered with cloths
+constantly wet with it. In ulcers or wounds it may be used in the form
+of a poultice, by stirring ground elm into the solution, the strength
+to be regulated according to the virulence of the attack. Ordinarily,
+ten drops to the ounce is strong enough for the cutaneous form of the
+disease and in dressings for wounds or recent injuries. If the
+inflammation threatens to spread rapidly, it should be increased to
+twenty or more drops to the ounce of water.
+
+The antiseptic properties of this remedy render it of additional
+value, as it will certainly destroy the tendency to unhealthy
+suppuration, and thus prevent septicæmia.
+
+In the treatment of hundreds of cases of erysipelas but one fatal case
+has occurred, and that one in an old and depraved system. In the less
+violent attacks no other remedy was used, but where constitutional
+treatment was indicated, the usual appropriate tonics were prescribed.
+
+There is no question in my mind but that creosote is as much a
+specific in erysipelas as quinine is in intermittent fever, and may be
+used with as much confidence.--_St. Louis Med. Jour._
+
+       *       *       *       *       *
+
+
+
+
+A NEW APPARATUS FOR THE STUDY OF CARDIAC DRUGS.
+
+By WILLIAM GILMAN THOMPSON, M.D., New York.
+
+
+The apparatus was devised by Mr. R.D. Gray (the inventor of the
+ingenious "vest camera" and other photographic improvements) and by
+myself. I described what was required and suggested various
+modifications and improvements, but the mechanical details were worked
+out exclusively by him. To test the rapidity of the camera, we
+photographed a "horse-timer" clock, with a dial marking quarter
+seconds, and succeeded in taking five distinct photographs in half a
+second with _one_ lens, which has never before been accomplished
+excepting by Professor Marey,[1] at the College de France, who has
+taken successive views of flying birds, falling balls, etc., with one
+lens at a very rapid rate. His camera was unknown to me until after
+mine was constructed, so that as a success in photography alone the
+work is interesting.
+
+  [Footnote 1: La Methode Graphique (Supplement), Paris, 1885.]
+
+The camera consists of a circular brass box, 5½ inches in diameter and
+1¼ inches deep, containing a circular vulcanite shutter with two
+apertures, behind which is placed a circular dry plate. Both plate and
+shutter are revolved in opposite directions to each other by a simple
+arrangement of four cogged wheels moved by a single crank. The box is
+perforated at one side by a circular opening, 1¾ inches in diameter,
+from the margin of which projects at a right angle a long brass tube
+(Fig. 1), which carries the lens. In Fig. 2 the lid of the box has
+been removed, and the bottom of the box, with the wheels, springs, and
+partially closed shutter, is presented. The lid is double--that is, it
+is a flat box in itself. It contains nothing but the dry plate,
+supported at its center upon a small brass disk, against which disk it
+is firmly pressed by a pivot attached to a spring fastened in the lid.
+The aperture in one side of this double lid, which corresponds with
+that seen in the floor of the box, may be closed by a slide, so that
+the lid containing the plate can be removed like an ordinary plate
+holder and carried to a dark room, where it is opened and the plate is
+changed. When the lid is replaced this slide is removed, and as the
+shutter is made to revolve, the light falls upon whatever portion of
+the dry plate happens to be opposite the opening.
+
+By reference to Fig. 2, it will be seen that when the large wheel
+which projects outside of the box is revolved by a crank, it turns the
+small ratchet wheel, which bears an eccentric pawl. (The crank has
+been removed in Fig. 2; it is seen in Fig. 1.) The central wheel has
+only six cogs. The pawl is pressed into one of these cogs by a spring.
+It pushes the central wheel around one-sixth of its circumference,
+when it returns to be pressed into the next cog. While the pawl
+returns, it necessarily leaves the central wheel at rest, and whatever
+momentum this wheel carries is checked by a simple stop pressed by a
+spring upon the opposite side. The central wheel carries a square
+axle, which projects through a small hole in the center of the double
+lid and fits into the brass disk before alluded to, causing the disk
+to revolve with the axle. The disk is covered by rubber cloth; and as
+the dry plate is pressed firmly against the rubber surface by the
+spring in the lid, the plate adheres to the rubber and revolves with
+the disk. Thus every complete revolution of the central wheel in the
+floor of the box carries with it the dry plate, stops it, and moves it
+on again six times. The velocity of revolution of the plate is only
+limited by the rapidity with which one can turn the crank.
+
+The shutter is revolved in the opposite direction by a wheel whose
+cogs are seen fitting into those of the little wheel carrying the
+eccentric pawl.
+
+[Illustration: FIG. 1.--THE CAMERA MOUNTED.]
+
+The two apertures in the shutter are so placed that at the instant of
+exposure of the plate it is momentarily at rest, while the plate when
+moving is covered by the shutters. This arrangement prevents vibration
+of the plate and blurring of the image. The camera is mounted by two
+lateral axles with screw clamps upon two iron stands, such as are in
+common use in chemical laboratories. A brass rod attached to the tube
+steadies it, and allows it to be screwed fast at any angle
+corresponding to the angle at which the heart is placed. It is thus
+easy to put a manometer tube in the femoral artery of an animal, bend
+it up alongside of the exposed heart, and simultaneously photograph
+the cardiac contraction and the degree of rise of the fluid in the
+manometer(!). The tube is arranged like the draw tube of a microscope.
+It is made long, so as to admit of taking small hearts at life-size.
+The stand carries a support for the frog or other animal to be
+experimented upon, and a bottle of physiological salt solution kept
+warm by a spirit lamp beneath.
+
+[Illustration: FIG. 2.--INTERIOR OF THE CAMERA.]
+
+The whole apparatus is readily packed in a small space. I have already
+taken a number of photographs of various hearts and intestines with
+it, and the contraction of the heart of the frog produced by
+_Strophanthus hispidus_, the new cardiac stimulant, is seen in Fig. 3,
+taken by this new instrument. The apparatus has the great advantage
+that six photographs of a single cardiac pulsation, or of any muscular
+contraction, may be easily taken in less than one second, or, by
+simply turning the crank slower, they may be taken at any desired rate
+to keep pace with the rhythm of the heart. The second hand of a watch
+may be placed in the field of view and simultaneously photographed
+with the heart, so that there can be no question about the series of
+photographs all belonging to one pulsation.
+
+[Illustration: FIG. 3.--PHOTOGRAPHS OF THE HEART IN MOTION.
+
+1, Normal diastole; 2, auricular systole; 3, ventricular systole. 1,
+2, 3 were taken in a half second; 4, 5, 6, same as 1, 2, 3, after
+injection of toxic dose of Strophanthus hispidus. 4, 5, 6 were taken
+in a half second. The pulse rate was 74.]
+
+I have already called attention[13] to the ease with which these
+photographs are enlarged for lecture room demonstration, either on
+paper or in a stereopticon, and the ease with which they may be
+reproduced in print to illustrate the action of drugs.
+
+[Footnote 13: _Medical Record_, loc. cit.; Recent Advances in Methods
+of Studying the Heart, _Medical Press_, Buffalo, March 1, 1886, p.
+234; Instantaneous Photographs of the Heart, Johns Hopkins University
+Circulars, March, 1886, p. 60.]
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+The Project Gutenberg eBook of Scientific American Supplement, October 2, 1886
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+
+The Project Gutenberg EBook of Scientific American Supplement, No. 561,
+October 2, 1886, 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. 561, October 2, 1886
+
+Author: Various
+
+Release Date: July 27, 2005 [EBook #16360]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Juliet Sutherland, Jeannie Howse, Victoria
+Woosley and the Online Distributed Proofreading Team at
+www.pgdp.net
+
+
+
+
+
+
+</pre>
+
+<p class="timg"><a href="./images/title.png"><img src="./images/title_th.png" alt="Issue Title" /></a></p>
+<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 561</h1>
+<h2>NEW YORK, OCTOBER 2, 1886</h2>
+<h4>Scientific American Supplement. Vol. XXII., No. 564.</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 />
+
+<div class="center">
+<table summary="Contents" border="0" cellspacing="5">
+<colgroup span="3" align="left"></colgroup>
+<tr>
+<th colspan="2" align="center">TABLE OF CONTENTS.</th>
+</tr>
+<tr><td valign="top">I.</td><td align="left"><a href="#art01">BOTANY.&mdash;A Century Plant in Bloom.&mdash;Interesting account of
+      the recent blossoming of an <i>Agave Americana</i> at
+      Auburn, N.Y.</a></td><td>8965</td></tr>
+
+<tr><td></td><td align="left"><a href="#art02">Alpine Flowers in the Pyrenees.&mdash;1 illustration.</a></td><td>8965</td></tr>
+
+<tr><td valign="top">II.</td><td align="left"><a href="#art03">CHEMISTRY.&mdash;Probable Isolation of Fluorine.&mdash;Decomposition
+      of hydrofluoric acid by an electric current.&mdash;By M.H.
+      MOISSAN.&mdash;Production of a new body, possibly fluorine, or
+      perfluoride of hydrogen.</a></td><td>8963</td></tr>
+
+<tr><td></td><td align="left"><a href="#art04">The Determination of Nitric Acid by the Absorption of Nitric
+      Oxide in a Standard Solution of Permanganate of Potash.&mdash;
+      By H.N. MORSE and A.F. LINN. Full description of a new and
+      important volumetric determination.&mdash;1 illustration.</a></td><td>8964</td></tr>
+
+<tr><td></td><td align="left"><a href="#art05">Water of Crystallization.&mdash;By W.W.J. NICOL, M.A., D.Sc.&mdash;
+      Discussion of the state of water of crystallization in a
+      salt in solution.</a></td><td>8964</td></tr>
+
+<tr><td valign="top">III.</td><td align="left"><a href="#art06">ENGINEERING.&mdash;Combustion, Fire Boxes, and Steam Boilers&mdash;By
+      JOHN A. COLEMAN.&mdash;Address before the June Convention of
+      the Master Mechanics' Association.</a></td><td>8953</td></tr>
+
+<tr><td></td><td align="left"><a href="#art07">Compound Hydraulic Presses.&mdash;Different forms of presses
+      designed for pressing bales for shipment.&mdash;Very fully
+      illustrated by 8 figures.</a></td><td>8951</td></tr>
+
+<tr><td></td><td align="left"><a href="#art08">Examination Papers in General Construction.&mdash;Eighty-six
+      questions in engineering propounded by the civil service
+      examiners of New York city.</a></td><td>8956</td></tr>
+
+<tr><td valign="top">IV.</td><td align="left"><a href="#art09">MEDICINE AND PHYSIOLOGY.&mdash;A New Apparatus for the Study of
+      Cardiac Drugs.&mdash;By WILLIAM GILMAN THOMPSON, M.D.&mdash;Ingenious
+      application of instantaneous photography to the study
+      of heart movements.&mdash;Apparatus and views produced.&mdash;3
+      illustrations.</a></td><td>8966</td></tr>
+
+<tr><td></td><td align="left"><a href="#art10">Creosote a Specific for Erysipelas,&mdash;A new cure for this
+      complaint.</a></td><td>8966</td></tr>
+
+<tr><td valign="top">V.</td><td align="left"><a href="#art11">METALLURGY.&mdash;Primitive Iron Manufacture.&mdash;Iron furnace
+      and blowing apparatus in use in Bengal.&mdash;2 illustrations.</a></td><td>8962</td></tr>
+
+<tr><td valign="top">VI.</td><td align="left"><a href="#art12">MINING ENGINEERING.&mdash;The Catastrophe at Chancelade.&mdash;
+      Application of photography to investigating mine disasters.
+      &mdash;4 illustrations.</a></td><td>8962</td></tr>
+
+<tr><td valign="top">VII.</td><td align="left"><a href="#art13">MISCELLANEOUS.&mdash;Celebration of the 500th Anniversary of the
+      University of Heidelberg. August, 1886.</a></td><td>8957</td></tr>
+
+<tr><td></td><td align="left"><a href="#art14">Useful Bags and How to Make Them.&mdash;Interesting paper on the
+      trunk makers' art.&mdash;4 illustrations.</a></td><td>8960</td></tr>
+
+<tr><td valign="top">VIII.</td><td align="left"><a href="#art15">NAVAL ENGINEERING.&mdash;Atlantic Steamers.&mdash;By W. JOHN.&mdash;
+      Exhaustive comparison of representative Atlantic liners
+      and war ships.&mdash;3 illustrations.</a></td><td>8954</td></tr>
+
+<tr><td></td><td align="left"><a href="#art16">Jet Propellers.&mdash;Hydraulic propulsion of vessels.&mdash;
+      Mathematical examination of this subject.</a></td><td>8951</td></tr>
+
+<tr><td valign="top">IX.</td><td align="left"><a href="#art17">ORDNANCE.&mdash;The New Army Gun.&mdash;Description of the 8-inch
+      steel gun as manufactured at the West Point, N.Y.,
+      Foundry.&mdash;1 illustration.</a></td><td>8952</td></tr>
+
+<tr><td valign="top">X.</td><td align="left"><a href="#art18">PHYSICS.&mdash;A New Thermo Regulator.&mdash;1 illustration.</a></td><td>8959</td></tr>
+
+<tr><td></td><td align="left"><a href="#art19">Cohesion and Cohesion Figures.&mdash;By WILLIAM ACKROYD,
+      F.I.C.&mdash;Laws of vortex rings examined, and relation of
+      solubility to cohesion.</a></td><td>8963</td></tr>
+
+<tr><td></td><td align="left"><a href="#art20">Pipette for taking the Density of Liquids.&mdash;Apparatus and
+      calculations for use.&mdash;1 illustration.</a></td><td>8959</td></tr>
+
+<tr><td valign="top">XI.</td><td align="left"><a href="#art21">TECHNOLOGY.&mdash;Impurities in Photographic Chemicals, and
+      Tests for Same.&mdash;Table referred to in a paper read before
+      the Birmingham Photographic Society by G.M. Jones, M.P.S.</a></td><td>8957</td></tr>
+
+<tr><td></td><td align="left"><a href="#art22">Molasses, how made.<ins class="trn" title="Transcriber's Note: Original had this sentence as the beginning of the next TOC entry">&mdash;Work on Plantations Graphically Described.</ins></a></td><td>8961</td></tr>
+
+<tr><td></td><td align="left"><a href="#art23">Optical errors and human mistakes.&mdash;By ERNST GUNDLACH.&mdash;On the examination
+      of optical glasses.&mdash;A paper read before the Buffalo
+       meeting of the A.A.A.S.</a></td><td>8963</td></tr>
+
+<tr><td></td><td align="left"><a href="#art24">Soap.&mdash;By HENRY LEFFMANN, Ph.D.</a></td><td>8962</td></tr>
+
+<tr><td></td><td align="left"><a href="#art25">Somzee's New Gas Burners.&mdash;Interesting description of
+      regenerative burners.&mdash;9 figures.</a></td><td>8958</td></tr>
+
+<tr><td></td><td align="left"><a href="#art26">The Clamond Gas Burner.&mdash;Of value as a supplement to the
+      above named article, describing an incandescent burner.
+      &mdash;1 illustration.</a></td><td>8959</td></tr>
+
+<tr><td></td><td align="left"><a href="#art27">Wood Oil.&mdash;A new industry worked on the large scale in Sweden.</a></td><td>8962</td></tr>
+</table></div>
+<hr />
+
+
+
+
+
+<h2><a name="art07" id="art07"></a><a name="Page_8951" id="Page_8951"></a>COMPOUND HYDRAULIC PRESSES.</h2>
+
+
+<p>In a hydraulic packing press, the work done by the ram during one
+stroke may be roughly divided into two periods, in the first of which
+the resistance, although gradually increasing, may be called light,
+while in the second the resistance is heavy. The former of these two
+periods embraces the greater part of the stroke, and it is only a
+small proportion at the end which requires the exercise of the full
+power of the press to bring the material to the determined degree of
+consolidation. Consequently, if a hydraulic press is to be worked so
+as to waste no time, it requires to be provided with means by which
+its table may be made to rise rapidly during the portion of the stroke
+when the resistance is small, and afterward more slowly when the
+entire power of the pumps is being expended upon the final squeeze.
+Many methods of obtaining this end have been devised, and are in
+common use both here and abroad. It is, however, more particularly in
+the packing of raw material that such appliances are useful, since the
+goods pressed into bales in this country are not usually of a very
+yielding nature, and consequently do not require a long stroke to
+bring them to a high state of compression. In India and Egypt, from
+whence cotton is sent in bales, presses must have a long stroke; and
+unless they can be worked rapidly, a very considerable amount of plant
+is required to get through a moderate quantity of work. To meet the
+necessities of these countries, Mr. Watson has devised several forms
+of press in which not only is the table made to rise rapidly through
+the greater part of its stroke, but the rams are kept almost
+constantly in motion, so that the time occupied in filling the box
+with raw cotton and in placing the ties round the bales is not lost.</p>
+
+<p class="center"><a href="./images/1a.png"><img src="./images/1a_th.png" alt="COMPOUND HYDRAULIC PRESS. FIGS. 1 and 2." /></a><br /> COMPOUND HYDRAULIC PRESS. FIGS. 1 and 2.</p>
+
+<p>We illustrate four forms of Mr. Watson's presses, Fig. 1 being an
+earlier construction, which, although very rapid at the date at which
+it was brought out, has been far surpassed in celerity by the
+arrangements shown in Figs. 3 to 8. It was introduced in 1873, and
+forty-three presses according to this design were sent to India by the
+makers, Messrs. Fawcett, Preston &amp; Co., of Ph&oelig;nix Foundry,
+Liverpool, between that year and 1880. Four presses of this kind are
+worked by one engine, having a cylinder 20 in. by 3 ft. stroke, and
+driving eighteen to twenty pumps of varying diameter and short stroke.
+The press has two long-stroke rams, LL, of small diameter, to compress
+the loose material, and two short-stroke rams, FF, of large diameter,
+to give the final squeeze. These two pairs of rams act alternately,
+the one pair being idle while the other is in operation. The lashing
+of the bale takes place while the larger rams are in action, the bale
+being supported on the grid, B, which is pushed under it through
+grooves formed in the press-head, S (Fig. 1). When the grid is in
+place the press-head can be lowered, and the box be filled, while the
+bale is receiving its final squeeze from the inverted rams above.</p>
+
+<p>In Figs. 1 and 2 the press is shown in the position it would occupy if
+the bale, M, were just completed and ready to be pushed out, and the
+box, N, were full of material. The filling doors, CC, are shown turned
+back level with the floor, the main doors, AA, are open, as are also
+the end doors, KK, to admit the men to fasten up the bale. If water be
+admitted to the subsidiary cylinder, H, the head, G, and two rams, FF,
+will be raised, and then the bale, M, can be thrown out finished. All
+the doors are now closed and water admitted to the rams, LL. These
+immediately rise, pushing the contents of the box, N, before them, and
+compressing them until the table, S, reaches the level of the grid, B.
+At this moment the tappet rod, D, shuts off the water, and withdraws
+the bolt of the doors, AA, which fly open. The grid, B (Fig. 2), is
+then run through the grooves in the press-head, S, and the rams, LL,
+are allowed to descend ready for a baling cloth to be inserted through
+the doors, EE, and for the box, N, to be refilled. At the same time
+the head, G, comes down on to the bale and compresses it still
+further, while the men are at work lashing it. When the material is in
+hanks, like jute, the rams, LL, are lowered slowly, while a man
+standing inside the box, at about the level of the floor, packs the
+material neatly on the table.</p>
+
+<p>These presses can be worked with great rapidity, the average output
+during a day varying from 21 to 28 bales an hour. The consumption of
+coal per bale is 9 lb. of Bengal coal, in value about ¾d. The density
+of the cotton bales produced is about 45 lb. per cubic foot, 400 lb.
+measuring a little under 9 cubic feet for shipment. In the case of
+jute or jute roots, the same weight occupies 10 cubic feet on an
+average. But rapid as this press is in action, the necessities of
+recent business in India have called for still more expeditious
+working, and to meet this demand Mr. Watson produced his compound
+press, in which the economy of time is carried to its utmost
+development. By the addition of a second pair of long-stroke rams the
+output of the press has been trebled, being raised to 80 bales per
+hour. To effect this, there is one pair of powerful rams, as in the
+press just described, but two pairs of the long-stroke rams. Further,
+each pair of the small-diameter rams is fitted with two boxes, one of
+which is always being filled while the other is being pressed. The
+rams in rising compress the material into a small cell or box,
+situated above the box in which raw cotton is thrown. On the top of
+the ram head there is a loose lashing plate, which, at the finish of
+the action of the rams, is locked in the cell by bolts actuated by a
+suitable locking gear. While in this cell the bale has the lashing
+ropes put round it, and then it is placed under the large rams for the
+final squeeze, during which the ties or ropes are permanently secured.
+Thus neither of the small presses has even to wait while its box is
+being filled, or while the previously pressed bale is being lashed.
+Even in the large press, when the ties are finally fastened, the time
+occupied does not exceed three-quarters of a minute, and is often much
+less.</p>
+
+<p class="center"><a href="./images/2a.png"><img src="./images/2a_th.png" alt="COMPOUND HYDRAULIC PRESS. FIGS. 3 and 4." /></a><br /> COMPOUND HYDRAULIC PRESS. FIGS. 3 and 4.</p>
+
+<p>This press is shown in Figs. 3 and 4. The small rams are arranged at
+either side of the large ones, which, in this case, are not inverted.
+To each of the smaller presses there is a pair of boxes mounted on a
+vertical column, around which they can revolve to bring either box
+over the rain head. When the left hand rams rise, the material is
+delivered into the cell, D, which previously has had its doors (Fig.
+4) closed. To permit of the cell, D, being moved out of the way, it is
+mounted so that it can revolve on one of the columns of the main
+press, first into the position shown at B (Fig. 4), and afterward to C
+(Fig. 3). While at D, the bale in the cell (called from its
+construction a revolver) is partly lashed, the ties or ropes being put
+into position. It is then rotated until it comes over the large rams,
+where the bale is still more compressed and secured.</p>
+
+<p>It must be admitted that this press provides for the greatest possible
+economy of time, and for the largest output, for the capital employed,
+which can be attained. The rams and the men are constantly in action,
+and not a single moment is lost. For filling each box 78 seconds are
+allowed, and there is ample time for the preliminary lashing.</p>
+
+<p class="center"><a href="./images/2b.png"><img src="./images/2b_th.png" alt="COMPOUND HYDRAULIC PRESS. FIGS. 5 and 6." /></a><br /> COMPOUND HYDRAULIC PRESS. FIGS. 5 and 6.</p>
+
+<p>Figs. 5 and 6 show a modification of this press, designed to turn out
+sixty bales per hour. It has only one set of long-stroke rams, with
+three revolvers. The bale receives its preliminary lashing while in
+the position, B (Fig. 6). Fifty-three seconds are available for
+filling the box, and the same time for the preliminary lashing. It is
+found, however, that three-quarters of a minute is sufficient for the
+complete hooping of a bale.</p>
+
+<p class="center"><a href="./images/1b.png"><img src="./images/1b_th.png" alt="COMPOUND HYDRAULIC PRESS. FIGS. 7 and 8." /></a><br /> COMPOUND HYDRAULIC PRESS. FIGS. 7 and 8.</p>
+
+<p>Figs. 7 and 8 show a similar press intended for jute pressing. This
+has only one box, which is fixed, as the material has to be packed in
+an orderly manner. Its speed is sixty bales an hour.&mdash;<i>Engineering.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art16" id="art16"></a>JET PROPELLERS.&mdash;HYDRAULIC PROPULSION OF VESSELS.</h2>
+
+
+<p>Certain mechanical devices appear to exercise a remarkable influence
+on some minds, and engineers are blamed for not adopting them, in no
+very measured terms in some cases. It is not in any way necessary that
+these devices should have been invented by the men who advocate their
+adoption, in order to secure that advocacy. The intrinsic attractions
+of the scheme suffice to evoke eulogy; and engineers sometimes find it
+very difficult to make those who believe in such devices understand
+that there are valid reasons standing in the way of their adoption.
+One such device is hydraulic propulsion. A correspondent in a recent
+impression suggested its immediate and extended use in yachts at all
+events, and we willingly published his letter, because the system does
+no doubt lend itself very freely to adoption for a particular class of
+yachts, namely, those provided with auxiliary power only. But because
+this is the case it must not be assumed that the jet propeller is
+better than screw or paddle-wheel propulsion; and it is just as well,
+before, correspondence extends further, that we should explain why and
+in what way it is not satisfactory. The arguments to be urged in favor
+of hydraulic propulsion are many and cogent; but it will not fail to
+strike our readers, we think, that all these arguments refer, not to
+the efficiency of the system, but to its convenience. A ship with a
+hydraulic propeller can sail without let or hindrance; a powerful pump
+is provided, which will deal with an enormous leak, and so on. If all
+the good things which hydraulic propulsion promises could be had
+combined with a fair efficiency, then the days of the screw propeller
+and the paddle wheel would be numbered; but the efficiency of the
+hydraulic propeller is very low, and we hope to make the reason why it
+is low intelligible to readers who are ignorant of mathematics. Those
+who are not ignorant of them will find no difficulty in applying them
+to what we have to <a name="Page_8952" id="Page_8952"></a>say, and arriving at
+similar conclusions in a different way.</p>
+
+<p>Professor Greenhill has advanced in our pages a new theory of the
+screw propeller. As the series of papers in which he puts forward his
+theory is not complete, we shall not in any way criticise it; but we
+must point out that the view he takes is not that taken by other
+writers and reasoners on the subject, and in any case it will not
+apply to hydraulic propulsion. For these reasons we shall adhere in
+what we are about to advance to the propositions laid down by
+Professor Rankine, as the exponent of the hitherto received theory of
+the whole subject. When a screw or paddle wheel is put in motion, a
+body of water is driven astern and the ship is driven ahead. Water,
+from its excessive mobility, is incapable of giving any resistance to
+the screw or paddle save that due to its inertia. If, for example, we
+conceive of the existence of a sea without any inertia, then we can
+readily understand that the water composing such a sea would offer no
+resistance to being pushed astern by paddle or screw. When a gun is
+fired, the weapon moves in one direction&mdash;this is called its
+recoil&mdash;while the shot moves in another direction. The same
+principal&mdash;<i>pace</i> Professor Greenhill&mdash;operates to cause the movement
+of a ship. The water is driven in one direction, the ship in another.
+Now, Professor Rankine has laid down the proposition that, other
+things being equal, that propeller must be most efficient which sends
+the largest quantity of water astern at the slowest speed. This is a
+very important proposition, and it should be fully grasped and
+understood in all its bearings. The reason why of it is very simple.
+Returning for a moment to our gun, we see that a certain amount of
+work is done on it in causing it to recoil; but the whole of the work
+done by the powder is, other things being equal, a constant quantity.
+The sum of the work done on the shot and on the gun in causing their
+motions is equal to the energy expended by the powder, consequently
+the more work we do on the gun, the less is available for the shot. It
+can be shown that, if the gun weighed no more than the shot, when the
+charge was ignited the gun and the shot would proceed in opposite
+directions at similar velocities&mdash;very much less than that which the
+shot would have had had the gun been held fast, and very much greater
+than the gun would have had if its weight were, as is usually the
+case, much in excess of that of the shot. In like manner, part of the
+work of a steam engine is done in driving the ship ahead, and part in
+pushing the water astern. An increase in the weight of water is
+equivalent to an augmentation in the weight of our gun and its
+carriage&mdash;of all that, in short, takes part in the recoil.</p>
+
+<p>But, it will be urged, it is just the same thing to drive a large body
+of water astern at a slow speed as a small body at a high speed. This
+is the favorite fallacy of the advocates of hydraulic propulsion. The
+turbine or centrifugal pump put into the ship drives astern through
+the nozzles at each side a comparatively small body of water at a very
+high velocity. In some early experiments we believe that a velocity of
+88 ft. per second, or 60 miles an hour, was maintained. A screw
+propeller operating with an enormously larger blade area than any pump
+can have, drives astern at very slow speed a vast weight of water at
+every revolution; therefore, unless it can be shown that the result is
+the same whether we use high speed and small quantities or low speed
+and large quantities, the case of the hydraulic propeller is hopeless.
+But this cannot be done. It is a fact, on the contrary, that the work
+wasted on the water increases in a very rapid ratio with its speed.
+The work stored up in the moving water is expressed in foot pounds by
+the formula</p>
+
+<p class="center"><span class="underline"> W v</span>&sup2;<br />2g</p>
+
+
+<p>where W stands for the weight of the water, and v for its velocity.
+But the work stored in the water must have been derived from the
+engine; consequently the waste of engine power augments, not in the
+ratio of the speed of the water, but in the ratio of the square of its
+speed. Thus if a screw sends 100 tons of water astern at a speed of 10
+ft. per second per second, the work wasted will be 156 foot tons per
+second in round numbers. If a hydraulic propeller sent 10 tons astern
+at 100 ft. per second per second, the work done on it would be 1,562
+foot tons per second, or ten times as much. But the reaction effort,
+or thrust on the ship, would be the same in both cases. The waste of
+energy would, under such circumstances, be ten times as great with the
+hydraulic propeller as with the screw. In other words, the slip would
+be magnified in that proportion. Of course, it will be understood that
+we are not taking into account resistances, and defects proper to the
+screw, from which hydraulic propulsion is free, nor are we considering
+certain drawbacks to the efficiency of the hydraulic propeller, from
+which the screw is exempt; all that we are dealing with is the waste
+of power in the shape of work done in moving water astern which we do
+not want to move, but cannot help moving. If our readers have followed
+us so far, they will now understand the bearing of Rankine's
+proposition, that that propeller is best which moves the greatest
+quantity of water astern at the slowest speed. The weight of water
+moved is one factor of the thrust, and consequently the greater that
+weight, other things being equal, the greater the propelling force
+brought to bear on the ship.</p>
+
+<p>It may be urged, and with propriety, that the results obtained in
+practice with the jet propeller are more favorable than our reasoning
+would indicate as possible; but it will be seen that we have taken no
+notice of conditions which seriously affect the performance of a
+screw. There is no doubt that it puts water in motion not astern. It
+twists it up in a rope, so to speak. Its skin frictional resistance is
+very great. In a word, in comparing the hydraulic system with the
+normal system, we are comparing two very imperfect things together;
+but the fact remains, and applies up to a certain point, that the
+hydraulic propeller must be very inefficient, because it, of all
+propellers, drives the smallest quantity of water astern at the
+highest velocity.</p>
+
+<p>There is, moreover, another and a very serious defect in the hydraulic
+propeller as usually made, which is that every ton of water passed
+through it has the velocity of the ship herself suddenly imparted to
+it. That is to say, the ship has to drag water with her. To illustrate
+our meaning, let us suppose that a canal boat passes below a stage or
+platform a mile long, on which are arranged a series of sacks of corn.
+Let it further be supposed that as the canal boat passes along the
+platform, at a speed of say five miles an hour, one sack shall be
+dropped into the boat and another dropped overboard continuously. It
+is evident that each sack, while it remains in the boat, will have a
+speed the same as that of the boat, though it had none before. Work
+consequently is done on each sack, in overcoming its inertia by
+imparting a velocity of five miles an hour to it, and all this work
+must be done by the horse towing on the bank. In like manner the
+hydraulic propeller boat is continually taking in tons of water,
+imparting her own velocity to them, and then throwing them overboard.
+The loss of efficiency from this source may become enormous. So great,
+indeed, is the resistance due to this cause that it precludes the
+notion of anything like high speeds being attained. We do not mean to
+assert that a moderate degree of efficiency may not be got from
+hydraulic propulsion, but it can only be had by making the quantity of
+water sent astern as great as possible and its velocity as small as
+possible. That is to say, very large nozzles must be employed. Again,
+provision will have to be made for sending the water through the
+propeller in such a way that it shall have as little as possible of
+the motion of the ship imparted to it. But as soon as we begin to
+reduce these principles to practice, it will be seen that we get
+something very like a paddle wheel hung in the middle of the boat and
+working through an aperture in her hull, or else a screw propeller put
+into a tube traversing her from stem to stern.</p>
+
+<p>We may sum up by saying that the hydraulic propeller is less efficient
+than the screw, because it does more work on the water and less on the
+boat; and that the boat in turn does more work on the water than does
+one propelled by a screw, because she has to take in thousands of tons
+per hour and impart to them a velocity equal to her own. Part of this
+work is got back again in a way sufficiently obvious, but not all. If
+it were all wasted, the efficiency of the hydraulic propeller would be
+so low that nothing would be heard about it, and we certainly should
+not have written this article.&mdash;<i>The Engineer.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art17" id="art17"></a>THE NEW ARMY GUN.</h2>
+
+
+<p>The cut we give is from a photograph taken shortly after the recent
+firings. The carriage upon which it is mounted is the one designed by
+the Department and manufactured by the West Point Foundry, about six
+months since. It was designed as a proof carriage for this gun and
+also for the 10 inch steel gun in course of construction. It is
+adapted to the larger gun by introducing two steel bushing rings
+fitted into the cheeks of carriage to secure the trunnion of the gun.</p>
+
+<p>The gun represented is an 8 inch, all steel, breech-loading rifle,
+manufactured by the West Point Foundry, upon designs from the Army
+Ordnance Bureau. The tube and jacket were obtained from Whitworth, and
+the hoops and the breech mechanism forgings from the Midvale Steel
+Company. The total weight of the gun is 13 tons; total length,
+including breech mechanism, 271 inches; length of bore in front of gas
+check, 30 calibers; powder space in chamber, 3,109 cubic inches;
+charge, 100 pounds. The tube extends back to breech recess from
+muzzle, in one solid piece. The breech block is carried in the jacket,
+the thread cut in the rear portion of the jacket. The jacket extends
+forward and is shrunk over the tube about 87½ inches. The re-enforce
+is strengthened by two rows of steel hoops; the trunnion hoops form
+one of the outer layers. In front of the jacket a single row of hoops
+is shrunk on the tube and extends toward the muzzle, leaving 91 inches
+of the muzzle end of the tube unhooped. The second row of hoops is
+shrunk on forward of the trunnion hoops for a length of 38 inches to
+strengthen the gun, and the hoop portion forms three conical frustums.
+The elastic resistance of the gun to tangential rupture over the
+powder chamber is computed by Claverino and kindred formulas to be
+54,000 lb. per square inch.</p>
+
+<p class="center"><img src="./images/2c.png" alt="THE ARMY 8 INCH STEEL GUN WITH CARRIAGE." /><br /> THE ARMY 8 INCH STEEL GUN WITH CARRIAGE.</p>
+
+<p>The breech mechanism is modeled after the De Bange system. The block
+has three smooth and three threaded sectors, and is locked in place by
+one-sixth of a turn of a block, and secured by the eccentric end of a
+heavy lever, which revolves into a cut made in the rear breech of the
+gun. The gas check consists of a pad made of two steel plates or cups,
+between which is a pad of asbestos and mutton suet formed under heavy
+pressure. The rifling consists of narrow grooves and bands, 45 of
+each. The depth of the groove is six one-hundredths of an inch.</p>
+
+<p>Although the gun is designed for a charge of 100 pounds, it is
+believed that it can be increased to 105 pounds without giving
+dangerous pressure, and the intention is to increase the charge to
+that amount when the new powder is received from Du Pont.</p>
+
+<p>The following is a very full synopsis of the official report of the
+preliminary firings&mdash;13 rounds&mdash;with this gun:</p>
+
+<p>The first seven rounds were fired with German cocoa powder, which was
+received from Watervliet Arsenal. There were two kinds of cartridges,
+one kind weighing 85 pounds, and having 30 grains in each layer, the
+other weighing 100 lb., and having 27 grains in each layer. In two of
+the first seven rounds the weight of the charge was 65 pounds, the
+projectiles weighing 182 and 286 pounds; in the next two rounds
+charges of 85 pounds were fired, the projectiles, as before, weighing
+182 and 286 pounds, while in the last three of the rounds fired with
+cocoa powder the charge was 100 lb., while the weight of the
+projectile was 182, 235, and 286 pounds. At the seventh round was
+fired the normal charge, 100 lb. of powder and a projectile weighing
+286 pounds, for which the gun was designed. The mean pressure for this
+round, determined by two crusher <a name="Page_8953" id="Page_8953"></a>gauges, was
+32,800 pounds, and the velocity at 150 feet was 1,787 feet.</p>
+
+<p>Two kinds of Du Pont's brown prismatic powder, marked P.A. and P.I.,
+were then fired. With the normal charge of P.A. powder (round 12 of
+the record), the mean pressure was 35,450 pounds, the velocity at 150
+feet was 1,812 feet. For P.I. powder (round 13 of the record), the
+pressure was 26,925 pounds, the velocity was 1,702 feet, and a
+considerable amount of unconsumed powder was ejected, showing that the
+P.I. powder is not a suitable one for this piece. The highest pressure
+indicated with the normal charge of P.A. powder was 36,200 pounds,
+exceeding by 1,200 pounds the provisional limit of pressure.</p>
+
+<p>At the fifth round the breech block opened with some difficulty, and
+an examination showed that the resistance resulted from the diametral
+enlargement of the rear plate. Directions have been given to correct
+this defect. The star gauge records show that no material change took
+place in the diameter of the chamber or the bore. From 30 inches to 54
+inches (measured from base of the breech), there was a diminution in
+diameter of from 0.001 in. to 0.002 in.; in rear of 30 inches there
+was no change. No enlargement in the shot chamber exceeded 0.001 in.
+From the bottom of the bore (the beginning of the rifling) to the
+muzzle the average enlargements were as follows: in. to 6 in., 0.005
+in.; 7 in. to 14 in., 0.003 in.; 15 in. to 29 in., 0.002 in.; 30 in.
+to muzzle, 0.002 to 0.001 in.</p>
+
+<p>After the third round the joint between the D. and D. rings opened
+slightly on the top, and measured after the 13th round showed that the
+opening was about 0.004 in. wide. It cannot at present be stated
+whether or not this opening increased during firing, but the defect
+has been noted and will be carefully observed. Enough cocoa powder
+remains to allow a comparison to be made with such brown prismatic
+powder as may be adopted finally. No firing has been done as yet to
+test the best position for the bands, but it will take place as soon
+as enough of some standard powder is obtained to fire ten consecutive
+rounds.&mdash;<i>Army and Navy Journal.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art06" id="art06"></a>COMBUSTION, FIRE-BOXES, AND STEAM BOILERS.<a name="FNanchor_1" id="FNanchor_1"></a><a href="#Footnote_1"><sup>1</sup></a></h2>
+
+<h3>By JOHN A. COLEMAN.</h3>
+
+
+<p>Mr. Chairman and gentlemen: I was rash enough some time ago to promise
+to prepare a paper for this occasion, the fulfillment of which prior
+engagements have absolutely prevented.</p>
+
+<p>I would greatly prefer to be let off altogether, but I do not like to
+break down when expected to do anything; and if you have the patience
+to listen for a few minutes to the reflections of an &quot;outsider,&quot; I
+will endeavor to put what I have to say in as concise form as I can,
+in such manner as will do no harm, even if it does no good.</p>
+
+<p>For many years I was connected with steam engineering. I was once with
+the Corliss Steam Engine Company, and afterward was the agent of Mr.
+Joseph Harrison, of Russian fame, for the introduction of his safety
+boilers.</p>
+
+<p>That brought me into contact with the heavy manufacturers throughout
+the Eastern States, and during that long experience I was particularly
+impressed with a peculiarity common to the mill owners, which, I
+believe it may be said with truth, is equally common to those
+interested in locomotive engineering, namely, how much we overlook
+common, every-day facts. For instance, we burn coal; that is, we think
+we do, and boilers are put into mills and upon railroads, and we
+suppose we are burning coal under them, when in reality we are only
+partially doing so. We think that because coal is consumed it
+necessarily is burned, but such is frequently very far from the fact.</p>
+
+<p>I wish upon the present occasion to make merely a sort of general
+statement of what I conceive to be combustion, and what I conceive to
+be a boiler, and then to try to make a useful application of these
+ideas to the locomotive.</p>
+
+<p>Treating first the subject of combustion, let us take the top of the
+grate-bars as our starting point. When we shovel coal upon the grate
+bars and ignite it, what happens first? We separate the two
+constituents of coal, the carbon from the hydrogen. We make a gas
+works. Carbon by itself will burn no more than a stone; neither will
+hydrogen. It requires a given number of equivalents of oxygen to mix
+with so many equivalents of carbon, and a given number of equivalents
+of oxygen to mix with so many of hydrogen to form that union which is
+necessary to produce heat. This requires time, space, and air, and one
+thing more, viz., heat.</p>
+
+<p>I presume that most of you have read Charles Williams' treatise upon
+&quot;Combustion,&quot; which was published many years ago, and which until
+recently was often quoted as an absolute authority upon the art of
+burning fuel under boilers. Mr. Williams in his treatise accurately
+describes the chemistry of combustion, but he has misled the world for
+fifty years by an error in reasoning and the failure to discuss a
+certain mechanical fact connected with the combination of gases in the
+process of combustion. He said: &quot;What is the use of heating the air
+put into a furnace? If you take a cubic foot of air, it contains just
+so many atoms of oxygen, neither more nor less. If the air be heated,
+you cause it to assume double its volume, but you have not added a
+single atom of oxygen, and you will require twice the space for its
+passage between the grate bars, and twice the space in the furnace,
+which is a nuisance; but if the air could be frozen, it would be
+condensed, and more atoms of oxygen could be crowded into the cubic
+foot, and the fire would receive a corresponding advantage.&quot; Mr.
+Williams proceeded upon this theory, and died without solving the
+perplexing mystery of as frequent failure as success which attended
+his experiments with steamship boilers. The only successes which he
+obtained were misleading, because they were made with boilers so badly
+proportioned for their work that almost any change would produce
+benefit.</p>
+
+<p>Successful combustion requires something more than the necessary
+chemical elements of carbon, hydrogen, and oxygen, for it requires
+something to cook the elements, so to speak, and that is heat, and for
+this reason: When the coal is volatilized in the furnace, what would
+be a cubic foot of gas, if cold, is itself heated and its volume
+increased to double its normal proportion. It is thin and attenuated.
+The cold air which is introduced to the furnace is denser than the
+gas. With dampers wide open in the chimney, and the gases and air
+passing into the flues with a velocity of 40 feet per second, they
+strike the colder surface of the tubes, and are cooled below the point
+of combustion before they have had time to become assimilated; and
+although an opponent in a debate upon steam boiler tests once stated
+that his thermometer in the chimney showed only 250 degrees, and
+indicated that all the value that was practical had been obtained from
+the coal, I took the liberty to maintain that a chemist might have
+analyzed the gases and shown there were dollars in them; and that if
+the thermometer had been removed from the chimney and placed in the
+pile of coal outside the boiler, it would have gone still lower; but
+it would not have proved the value to have been extracted from the
+coal, for it was not the complete test to apply.</p>
+
+<p>The condition of things in the furnace may be illustrated thus: If we
+should mingle a quart of molasses and a gallon of water, it would
+require considerable manipulation and some time to cause them to
+unite. Why? Because one element is so much denser than the other; but
+if we should mix a quart of the gallon of water with the quart of
+molasses, and render their densities somewhere near the density of the
+remaining water, and then pour the masses together, there would be a
+more speedy commingling of the two. And so with the furnace. I have
+always maintained that every furnace should be lined with fire-brick,
+in order that it shall be so intensely hot when the air enters that
+the air shall instantly be heated to the same degree of tenuity as the
+hot gases themselves, and the two will then unite like a flash&mdash;and
+that is heat. And here is the solution of the Wye Williams mystery of
+failure when cold air was introduced upon the top of a fire to aid
+combustion. The proof of the necessity for heat to aid the chemical
+assimilation of the volatilized coal elements is seen in starting a
+fire in a common stove. At first there is only a blue flame, in which
+the hand may be held; but wait until the lining becomes white hot, and
+then throw on a little coal, and you will find a totally different
+result. It is also seen in the Siemens gas furnace, with which you are
+doubtless familiar. There is the introduction of gas with its
+necessary complement of air. Until the furnace and retorts become
+heated, the air and gas flutter through only partially united, and do
+little good; but as soon as the retorts and furnace become thoroughly
+hot, the same gas and air will melt a fire-brick.</p>
+
+<p>These are common phenomena, which are familiar, but apt to be
+unnoticed; but they logically point to the truth that no furnaces
+should present a cooling medium in contact with fuel which is
+undergoing this process of digestion, so to speak. It will be very
+evident, I think, from these facts that water-legs in direct contact
+with a fire are a mistake. They tend to check a fire as far as their
+influence extends, as a thin sheet of ice upon the stomach after
+dinner would check digestion, and for the same reason, namely, the
+abstraction of heat from a chemical process. If fire-brick could be
+laid around a locomotive furnace, and the grate, of course, kept of
+the same area as before, it is my belief that a very important
+advantage would be at once apparent. An old-fashioned cast iron heater
+always produced a treacherous fire. It would grow dead around the
+outside next to the cold iron; but put a fire-clay lining into it, and
+it was as good as any other stove.</p>
+
+<p>If I have now made clear what I mean by making heat, we will next
+consider the steam boiler. What is a steam boiler? It is a thing to
+absorb heat. The bottom line of this science is the bottom of a pot
+over a fire, which is the best boiler surface in the world; there is
+water upon one side of a piece of iron and heat against the other. One
+square foot of the iron will transmit through it a given number of
+units of heat into the water at a given temperature in a given time;
+two square feet twice as many, and three, three times as many, and so
+on. Put a cover upon the pot, and seal it tight, leave an orifice for
+the steam, and that is a steam boiler with all its mysteries.</p>
+
+<p>The old-fashioned, plain cylinder boiler is a plain cylindrical pot
+over the fire. If enough plain cylinder boilers presenting the
+requisite number of square feet of absorbing surface are put into a
+cotton mill, experience has shown that they will make a yard of cotton
+cloth about as cheaply as tubular boilers. If this is so, why do not
+all put them in? Because it is the crudest and most expensive form of
+boiler when its enormous area of ground, brickwork, and its fittings
+are considered. Not all have the money or the room for them. To
+produce space, the area is drawn in sidewise and lengthwise, but we
+must have the necessary amount of square feet of absorbing surface,
+consequently the boiler is doubled up, so to speak, and we have a
+&quot;flue boiler.&quot; We draw in sidewise and lengthwise once more and double
+up the surface again, and that is a &quot;tubular boiler.&quot; That includes
+all the &quot;mystery&quot; on that subject.</p>
+
+<p>Now, we find among the mills, just as I imagine we should upon the
+railroads, that the almost universal tendency is to put in too small
+boilers and furnaces. To skimp at boilers is to spend at the coal
+yard. Small boilers mean heavy and over-deep fires, and rapid
+destruction of apparatus. In sugar houses you will see this frequently
+illustrated, and will find 16 inch fires upon their grates.</p>
+
+<p>We have found that, as we could persuade mill owners to put in more
+boilers and extend their furnaces, so that coal could be burned
+moderately and time for combustion afforded, we often saved as high as
+1,000 tons in a yearly consumption of 4,000.</p>
+
+<p>Now, when the ordinary locomotive sends particles of coal into the
+cars in which I am riding, I do not think it would be unfair criticism
+to say that the process of combustion was not properly carried out.
+When we see dense volumes of gas emitted from the stack, it is evident
+that a portion of the hard dollars which were paid for the coal are
+being uselessly thrown into the air; and it will be well to remember
+that only a little of the unburnt gas is visible to the eye.</p>
+
+<p>One point I wish to make is this: We find, as I have said, that as we
+spread out with boilers and furnaces in the mills, so that we can take
+matters deliberately, we save money.</p>
+
+<p>Now, coming again to locomotives. I think, if we examine the subject
+carefully, the fact will strike us a little curiously. The first
+locomotive built in Philadelphia weighed about 14 tons. Judging from
+the cut I have seen, I should think her furnace might have been 30
+inches square. We have gone from that little 14 ton engine to machines
+of 50 and 60 tons&mdash;perhaps more. The engines have been increased over
+four times, but I will ask you if the furnace areas have been
+increased (applause) in proportion? Some of the furnaces of the
+engines are six feet by three, but that is an increase of less than 3
+to 1 of furnace, as against 4 to 1 of weight of engine.</p>
+
+<p>When my attention was first called to this matter, I had supposed, as
+most people do who are outside of the railway profession, that there
+was something subtile and mysterious about railway engineering that
+none but those brought up to the business could understand. Possibly
+it is so, and I am merely making suggestions for what they are worth,
+but I think the position I have taken in this matter was established
+by some experiments of three weeks' duration, which I conducted
+between Milan and Como, in Italy, for the Italian government, in
+pulling freight trains up grades of 100 feet to the mile. The
+experiments were made with an engine built by the Reading Railroad.</p>
+
+<p>We competed with English, French, Belgian, and Austrian engines. These
+machines required the best of fuel to perform the mountain service,
+and could use coal dust only when it was pressed into brick. We used
+in the Reading Railroad machine different fuels upon different days,
+making the road trip of 120 miles each day with one kind of fuel. We
+used coal dust scraped up in the yards, also the best Cardiff coal,
+anthracite, and five kinds of Italian lignite, the best of which
+possesses about half the combustible value of coal.</p>
+
+<p>The results in drawing heavy freight trains were equally good with
+each fuel, the engine having at all times an abundance of steam on
+heavy grades, no smoke nor cinders, and no collection of cinders in
+the forward part of the engine.</p>
+
+<p>The fireman arranged his fires at a station, and did little or nothing
+except to smoke his pipe and enjoy the scenery until he reached the
+next station. An incident occurred to prove that we were not playing
+with the machine. They told me one morning that we should be given a
+load of 25 per cent less than the maximum load of an engine of her
+class (30 tons). We started up the 100 foot grade, and found we could
+barely crawl, and our engineer got furious over it. He thought they
+were repeating a trick already attempted by screwing down a brake in
+ascending a grade. We detected it, however, and found a pair of wheels
+nearly red hot. Upon this occasion we found nothing amiss, except full
+cars where they had reported only a light load. We pulled to the top
+of the hill, the steam blowing off furiously all the time.</p>
+
+<p>This was a new experience to the Italians, and might surprise some
+Americans. When we arrived at the station, the inspector-general and
+his corps of engineers were evidently amazed, and it was evident we
+had captured them. He said to me, &quot;I can congratulate you, signor, on
+possession of a superb machine.&quot;</p>
+
+<p>Afterward one of the engineers said to me: &quot;Do not let it be known
+that I told you what you have hauled or I shall lose my place, but you
+have drawn 50 per cent more than the maximum load of one of our 40 ton
+engines.&quot; I said: &quot;You attempted to 'stall' us, and when you try it
+again, be fair enough to give me a flat of pig iron, and as you pack
+cars on one end I will pack pig iron upon the engine until she will
+stick to the track, but rest assured that you will not be able to get
+that steam down.&quot; The experience with that engine proves conclusively
+to my mind that the general principles of steam making are the same
+for both stationary and locomotive practice. The grand secret of the
+success of that Wootten engine was the enormous area of the grate
+surface, being, if I remember correctly, 7 by 9 feet, permitting thin
+fires to be carried and complete combustion to be obtained before the
+gases reached the boiler tubes. An enormous crown sheet was presented,
+and that is where the bulk of the work of any boiler is done.</p>
+
+<p>Thin fires accomplish this. As already stated, a given amount of coal
+generates a given amount of gas, and this gas requires a given amount
+of air or oxygen. This air must be supplied through the grate bars and
+then pass through the interstices of the mass of heated coal. It
+requires about 10 cubic feet of air to consume one cubic foot of gas.
+In stationary boilers we find that if we use &quot;pea&quot; and &quot;dust&quot; coal, an
+extremely thin layer must be used, or the 10 feet of air per foot of
+gas cannot pass through it; if &quot;chestnut&quot; coal be used, the thickness
+may be increased somewhat; &quot;stove size&quot; allows a thickness of six
+inches, and &quot;lump&quot; much thicker, if any wise man could be found who
+would use that coarse, uneconomical size. Of course, I am speaking of
+anthracite coal. Opinions differ about &quot;soft coal,&quot; but the same
+general principle applies as regards an unobstructed passage of air
+through the hot bed of coal.</p>
+
+<p>Now, it will be agreed that the locomotive of the future must be
+improved to keep up with the times. Fierce competition requires
+increased efficiency and reduced expenses. I am told by you railroad
+gentlemen that the freight business of the country doubles every ten
+years. Trains follow close upon each other. What are you going to do?
+Are you to double, treble, or quadruple your tracks?</p>
+
+<p>It seems to me much remains yet to be done with the locomotive. We
+must burn a great deal less coal for the steam we make, and after we
+have made steam we must use that steam up more thoroughly. In the
+short cylinder required by locomotive service, the steam, entering at
+the initial pressure pushes the piston to the opposite end, and it
+then rushes out of the exhaust strong enough to drive another piston.
+Of every four dollars' worth of coal consumed, at least two dollars
+worth is absolutely thrown away. Or, of every ten thousand dollars
+spent for fuel, five thousand dollars are absolutely wasted. How can
+we save this? It would seem obvious that if steam rushes from the
+exhaust of an engine strong enough to drive another engine, the common
+sense of the thing would be to put another engine alongside and let
+the steam drive it, and we should get just so much more out of our
+four dollars' worth of coal. It seems evident that we must follow the
+lead of the steamship men, and compound <a name="Page_8954" id="Page_8954"></a>the
+locomotive engine, as they have done with the marine engine.</p>
+
+<p>Next we must attack the extravagant furnace, and increase its area and
+reduce the depth of the bed of coal. The difficulty of making this
+change seemed to me to be removed, on examining an engine on the
+Providence &amp; Bristol Railroad, the other day. The machine was made at
+the Mason Works, of Taunton. It was an engine and tender combined, the
+truck being at the rear end of the tender, and the driver placed well
+in advance of the fire-box, so that the maximum weight of both engine
+and tender rested upon the drivers. In thus removing the drivers from
+the proximity of the fire-box, abundant facility is afforded for
+widening the fire-box, so as to obtain a grate area as large as that
+of the Wootten engine or of a stationary boiler. It seems to me the
+increase of grate area can be obtained only by widening; for a length
+of more than six or seven feet is very hard upon the fireman. You
+certainly cannot get more power by deepening present fire-boxes,
+except by an enormously increased waste of fuel, which all will
+concede is already sufficiently extravagant.</p>
+
+<p>In arriving at the conclusion of these hasty and I fear somewhat
+incoherent remarks, I would say that the object aimed at for the
+improvement of the locomotive would be reached, first, by making steam
+economically, by employing such increased grate area as will permit
+running thin fires and moderate or comparatively slow draught; and,
+secondly, in economically using the steam which has been economically
+made by compounding the engine.</p>
+
+<p>I have given you merely the views of an &quot;outsider,&quot; who has had a
+somewhat extensive experience in stationary engineering, and who has
+observed locomotive practice in many parts of the world. These views
+are offered for what they are worth, as suggestions for future thought
+in designing engines, and as a sort of refresher upon rudimentary
+points which long familiarity with every-day phenomena causes us at
+times to overlook. I trust that your deliberations may aid in the
+speedy reduction of the expenses of transporting freight and
+passengers, for the benefit of the railroad companies and, in their
+turn, the advantage of the people at large.</p>
+
+<p><a name="Footnote_1" id="Footnote_1"></a><a href="#FNanchor_1">[1]</a></p><div class="note"><p>Address before the June Convention of the Master
+Mechanics' Association.</p></div>
+
+<hr />
+
+
+<h2><a name="art15" id="art15"></a>ATLANTIC STEAMERS.<a name="FNanchor_2" id="FNanchor_2"></a><a href="#Footnote_2"><sup>1</sup></a></h2>
+
+<h3>By W. JOHN.</h3>
+
+
+<p class="center"><a href="./images/4a.png"><img src="./images/4a_th.png" alt="Fig. 1&mdash;CITY OF ROME." /></a><br /> Fig. 1&mdash;CITY OF ROME.</p>
+
+<p>The author said that he hoped to bring before the meeting impartially
+certain facts which might be of interest, and which, when recorded in
+the pages of the &quot;Transactions,&quot; might be found of some use as data
+for future reference. In dealing with passenger steamers, he would do
+so principally from a shipbuilder's point of view; but the moment he
+commenced to think over Atlantic passenger ships as a shipbuilder, he
+was met by the question whether the present tendency toward divorcing
+the passenger and cargo trade from each other is likely to continue or
+not. If the answer is yes, then it seems to become an important
+question, for the present at least, how to build, on moderately small
+dimensions, the fastest, safest, and most economical passenger
+steamer, using all the most modern improvements to make her commodious
+and luxurious, and an easy sea boat into the bargain. If cargo is
+still to be carried in the passenger ships of the future, a moderate
+speed only will be aimed at in the immediate future, and every effort
+will be devoted to economy of fuel, comfort, and safety, with a fair
+carrying capacity. This latter policy is one which may possibly
+prevail at least for a time, as it has powerful supporters in
+Liverpool; but he could not help thinking that very high
+speeds&mdash;higher than we have yet attained&mdash;must eventually gain the
+day. He also thought that they were on the eve of important movements,
+which will indicate what the next step in the passenger trade is to
+be; for it must be remembered, among other things, that none of our
+present English transatlantic liners, even the latest, have yet been
+fitted with the latest modern improvements for economy of fuel or
+quick combustion, such as triple expansion engines or forced draught.
+They must, therefore, be at some disadvantage, other things being
+equal, compared with the ships of the future possessing them. The
+Great Eastern steaming up Milford Haven about twenty-five years ago
+between two lines of the channel fleet of old&mdash;two and three decked
+wooden line-of-battle ships&mdash;the whole fleet saluting with yards
+manned, was a sight to be remembered. More than this, that ship, with
+all her mournful career, has been a useful lesson and a useful warning
+to all naval architects who seriously study their profession&mdash;a lesson
+of what can be done in the safe construction of huge floating
+structures, and a warning that the highest flights of constructive
+genius may prove abortive if not strictly subordinated to the
+practical conditions and commercial requirements of the times. The
+Sirius and Great Western crossed the Atlantic in 1838, and in 1840 the
+first ship of the since celebrated Cunard Company made her first
+voyage. This was the Britannia, which, with her sister ships, the
+Arcadia, Caledonia, and Columbia, kept up the mail service regularly
+at a speed of about 8½ knots an hour. The Britannia was 207 ft. in
+length between perpendiculars, and 34 ft. 4 in. extreme breadth, 22
+ft. 6 in. depth of hold, 423 horse power&mdash;nominal&mdash;and 1,153 tons
+burden, built of wood, and propelled by paddles. In 1860 the Collins
+Line started in opposition to the Cunard, and, after a series of
+disasters, collapsed in 1858. This was three years after the Persia,
+the first Cunarder built of iron, had been completed. In 1850, also,
+the Inman Line was started with the City of Glasgow, of 1,600 tons
+builders' measurement, and 350 horse power. She was built of iron, and
+was the first screw steamer sent across the Atlantic from Liverpool
+with passengers, and was the pioneer of the great emigrant trade which
+Mr. Inman, above all others, did so much to develop and make cheap and
+comfortable for the emigrants themselves, as well as profitable to his
+company. That the builders of the celebrated old Great Britain, in
+1843, and Mr. Inman, in 1850, should have pronounced so decisively in
+favor of the screw propeller in preference to the paddle for ocean
+steaming is a proof of their true practical judgment, which time and
+practical experience have made abundantly clear. While the Cunard
+Company went on developing its fleet from the early wood paddle
+steamer Britannia of 1,130 tons in 1840 to the iron paddle steamers
+Persia, etc., in 1858, the iron screw steamer China of 1862, to the
+still more important screw steamers Bothnia and Scythia, vessels of
+4,335 tons, in 1874, the Inman and other lines were as rapidly
+developing in speed and size, if not in numbers. The year 1874 is
+memorable, for it saw the White Star steamers Britannic and Germanic
+put into the water, as well as the Inman steamer City of Berlin and
+the two before mentioned Cunard steamers, Bothnia and Scythia. By the
+addition of these two ships to their fleet the White Star Line,
+although started only in 1870, reached a front rank position in the
+New York passenger trade. The author gave in separate tables the logs
+of several of these ships, some from published documents and some
+kindly furnished by the owners. The Great Western had crossed the
+Atlantic from Bristol to New York in 15 days as early as 1838. The
+first Cunard steamer, the Britannic, was about the same speed, from 8¼
+to 8½ knots an hour. The average duration of the Cunard voyages in the
+year 1856 was 12.67 days from Liverpool to New York, and 11.03 days
+from New York to Liverpool. The Bothnia, in 1874, reduced the passage
+to about nine days. The White Star Britannic, in 1876, averaged 7 days
+18 hours 26 minutes outward from Queenstown to New York, and 9 days 6
+hours 44 minutes homeward, and has averaged for the last ten years 8
+days 9 hours 36 minutes outward, and 8 days 1 hour 48 minutes
+homeward. The City of Berlin, of the Inman Line, also built in 1874, 8
+days 10 hours 56 minutes, and homeward 8 days 2 hours 37 minutes; and
+for the nine years from 1875 to 1883 inclusive, averaged outward 8
+days 19 hours 56 seconds, and inward 8 days 8 hours 34 seconds; or,
+putting it into rounder figures, the Britannic had reduced the average
+passage between the two points to 8¼ days, and the City of Berlin to
+8½ days. From the year 1874 on to 1879 no further advance was made in
+Atlantic steaming, but in that year the Arizona was added to the Guion
+Line, and it soon became evident that another important stride had
+been made in the Atlantic passenger trade, which would lead to most
+important results. The results, as we all know, have been sufficiently
+startling. The Guion Line, which had started in 1866 with the
+Manhattan, had now the fastest passenger ship on the Atlantic. In
+spite of burning some fifty per cent. more coal than the Britannic,
+the ship was an obvious commercial success. The spirited policy which
+brought her into existence was appreciated by the public, and the
+other lines had to move forward. Then followed a period of rivalry,
+the Cunard Company building the Gallia and Servia, the Inman Company
+the City of Rome, and the Guion Line the Alaska, all of which were
+completed in 1881, and afterward the Oregon for the Guion
+Line&mdash;1883&mdash;the Aurania the same year for the Cunard Company, and,
+later still, the America for the National Line, and the Umbria and
+Etruria for the Cunard Company in 1885.</p>
+
+<p class="center"><a href="./images/4b.png">
+<img src="./images/4b_th.png" alt="Frames from outer edge of Tank to Upper Deck" />
+</a><br /> <i>Frames from outer edge of Tank to Upper Deck, 7 ×
+3½ × 8/16 for 250 ft. Amidships, for 60 ft. before and abaft these
+Points 6½ × 3½ × 6/16 at end of Vessel 5 × 3½ × 7/16, all spaced 24
+in. apart and all carried to Upper Deck, double from Bilge to Bilge in
+way of Engines.&mdash;Frames in Tank on Lattice and Solid Floors, 5 × 3½ ×
+8/16, Intermediate Frames, 8 × 4 × 9/16&mdash;Rev: Frames, 4½ × 3½ × 8/16,
+carried to Upper and Main Deck alternately double, 4½ × 4½ × 8/16 from
+Bilge to Bilge in E and B space.</i><br /><br />
+Fig. 2&mdash;SERVIA.</p>
+
+<p>Since the completion of the Etruria, for various reasons there has
+been a pause in the tremendous strides made since 1879, and we may
+briefly review the results. Taking the Britannic as a standard with
+her ten years' average of 8¼ days across, and her quickest passage of
+7 days 10 hours 53 seconds, we have now the following steamers of
+higher speeds. Taking them in the order of their absolutely fastest
+passage out or home, they stand thus:</p>
+
+<p class="center">TABLE I.</p>
+
+<div class='center'>
+<table border="0" cellpadding="4" cellspacing="0" summary="">
+<tr><th colspan="2"></th><th align='center'>Days.</th><th align='center'>Hours.</th><th align='center'>Mins.</th></tr>
+<tr><td align='center'>1</td><td align='left'>Etruria.</td><td align='center'>6</td><td align='right'>5</td><td align='right'>31</td></tr>
+<tr><td align='center'>2</td><td align='left'>Umbria (sister ship).</td><td align='left' colspan="3">slightly longer.</td></tr>
+<tr><td align='center'>3</td><td align='left'>Oregon.</td><td align='center'>6</td><td align='right'>10</td><td align='right'>35</td></tr>
+<tr><td align='center'>4</td><td align='left'>America.</td><td align='center'>6</td><td align='right'>13</td><td align='right'>44</td></tr>
+<tr><td align='center'>5</td><td align='left'>City of Rome.</td><td align='center'>6</td><td align='right'>18</td><td align='right'>0</td></tr>
+<tr><td align='center'>6</td><td align='left'>Alaska.</td><td align='center'>6</td><td align='right'>18</td><td align='right'>37</td></tr>
+<tr><td align='center'>7</td><td align='left'>Servia.</td><td align='center'>6</td><td align='right'>23</td><td align='right'>55</td></tr>
+<tr><td align='center'>8</td><td align='left'>Aurania.</td><td align='center'>7</td><td align='right'>1</td><td align='right'>1</td></tr>
+</table></div>
+
+<p>It will thus be seen that from the 15 days' passage or thereabout, of
+the earliest Atlantic steamers, we had got down in the days of the
+Scotia to about 9 days; in the Britannic to 8¼ days, and, at the
+present time, we have got to 6¼ days, with seven ships afloat that
+have done the passage under seven days, and capable of making their
+average passages range between 6½ and 7¼ days.</p>
+
+<p>Ranged in order of gross tonnage, these eight vessels stand as
+follows:</p>
+
+<p class="center">TABLE II.</p>
+
+<div class='center'>
+<table border="0" cellpadding="2" cellspacing="0" width="50%" summary="Ship, Gross Tonnage">
+<tr><td align='left'>1. City of Rome.</td><td align='right'>8,144</td></tr>
+<tr><td align='left'>2. Oregon.</td><td align='right'>7,375</td></tr>
+<tr><td align='left'>3. Aurania.</td><td align='right'>7,269</td></tr>
+<tr><td align='left'>4. Servia.</td><td align='right'>7,212</td></tr>
+<tr><td align='left'>5. Umbria.</td><td align='right'>7,129</td></tr>
+<tr><td align='left'>6. Etruria.</td><td align='right'>7,100</td></tr>
+<tr><td align='left'>7. Alaska.</td><td align='right'>6,586</td></tr>
+<tr><td align='left'>8. America.</td><td align='right'>5,528</td></tr>
+</table></div>
+
+<p>Here the America shows to advantage, for while being eighth in size
+she is fourth in point of speed, and from what the author can learn,
+although he had no authenticated details on the subject, he believed
+she is economical in coal consumption. He might perhaps be permitted
+to say that one of the most difficult subjects in connection with the
+propulsion of ships on which to get absolutely accurate data is that
+of coal consumption. The records of six to eight hours' trials for the
+purpose of ascertaining the coal consumption are absolutely worthless,
+as all shipbuilders and engineers know, and so far as English ships
+are concerned they are never attempted. Foreign owners frequently
+stipulate for such trials in their contracts with English
+shipbuilders, and get wonderfully economical results on paper, but the
+fact that the trials only extend over a few hours renders them
+valueless, however carefully the coal may be weighed during that
+period. An authentic record of the absolute quantity of coal consumed,
+say by each of the eight fastest Atlantic liners, together with their
+average indicated horse power on the voyage, for a series of voyages,
+would be extremely valuable.</p>
+
+<p>He gave, in Table III., the consumption per indicated horse power per
+hour for a number of ships. This table affords valuable data, for it
+gives, in addition to the dimensions, the moulded draught of water,
+the midship area, the displacement, the indicated horse power, the
+speed on trial, the coefficients for the lines both from the block or
+parallelopipedon, and also from the midship section prism, together
+with the length and angle of entrance obtained by Kirk's rule, the
+Admiralty displacement coefficient, together with the coal consumption
+per day and per indicated horse power per hour.</p>
+
+<p class="center"><a href="./images/4c.png"><img src="./images/4c_th.png" alt="Fig. 3&mdash;OREGON." /></a><br /> Fig. 3&mdash;OREGON.</p>
+
+<p>This table, as will be seen, contains some of the most important of
+the Atlantic liners, and also a number of other typical ships, which
+will add a variety to its interest and a value to it. The coefficient,
+which is contained in the thirteenth column of the table, viz.:</p>
+
+
+<div class="center">
+<table summary="equation">
+<tr><td colspan="2" align="center">Dis 2/3 × speed&sup3;</td></tr>
+<tr><td colspan="2">&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;&mdash;</td></tr>
+<tr><td align="center">I.H.P. ×</td><td align="center"><span class="underline">&radic;<span class="overline">(entrance.)</span></span><br />10</td></tr>
+</table>
+</div>
+
+<p>generally comes out for ships of similar type more nearly a constant
+in the true sense of the word than the corresponding Admiralty
+constant. As an example, we have the curves of resistance and horse
+power for the City of Rome and the Normandie, a large vessel of 6,000
+tons, which the Barrow Company built for the Compagnie Generale
+Transatlantique, in which the coefficient of fineness and the form of
+the lines pretty closely resemble each other below water; and if we <a
+name="Page_8955" id="Page_8955"></a>take from the curves the corresponding speeds and
+horse powers, and work out the constants by the two systems, we have
+at 14 knots the Admiralty constant for the City of Rome 322.2, and for
+the Normandie 304.8; and taking for a modified form of constant, the
+City of Rome gives 253.7 and the Normandie 251.9, which, as will be
+seen, are much closer together. Similarly, at 15 knots the Admiralty
+constant for the City of Rome is 310, and for the Normandie 295.2,
+while a modified constant comes out for the former at 245, and for the
+latter 244, again agreeing almost identically. The same at 16 knots,
+for the City of Rome the Admiralty constant comes out 297.6, and for
+the Normandie 282.8, while a modified constant comes out for the two
+ships 234.4 and 233.7 respectively, again showing marked agreement. It
+may be mentioned that in these two ships the engines are of a similar
+type, being three-crank tandem engines, and the propellers have in
+both pitch and surface practically the same proportions to the power
+and speed. The value of these modified constants will probably be
+found to increase as the speeds increase up to the limit and beyond
+that point at which wave resistance becomes an important factor.</p>
+
+<p class="center">TABLE III.</p>
+
+<div style="font-size: 80%; margin-left: -15%; margin-right: 115%;">
+<table border="1" width="100%" summary="Table III">
+<tr>
+<td class="tdc" rowspan="2">Name</td>
+<td class="tdc" rowspan="2">Length</td>
+<td class="tdc" rowspan="2">Breadth</td>
+<td class="tdc" rowspan="2">Moulded draught</td>
+<td class="tdc" rowspan="2">Midship area</td>
+<td class="tdc" rowspan="2"><span title="Distribution">Dist.</span></td>
+<td class="tdc" rowspan="2">Indicated H.P.</td>
+<td class="tdc" rowspan="2">Speed</td>
+<td class="tdc" rowspan="2">Block coefficient</td>
+<td class="tdc" rowspan="2">Midship section coefficient</td>
+<td class="tdc" rowspan="2">Prismatic midship section coefficient</td>
+<td rowspan="2" class="tdc" style="white-space: nowrap; font-size: 90%;">
+
+  <table summary="">
+  <tr>
+   <td>D<span style="letter-spacing:-.1em;"><sup>2</sup>/<sub>&nbsp;3</sub></span>&nbsp;&nbsp;&times;&nbsp;S<sup>3</sup>
+   </td>
+  </tr>
+  <tr>
+   <td><hr style="width:100%;height:1px;padding:0;margin:0;" />
+   </td>
+  </tr>
+  <tr>
+   <td>I.H.P.
+   </td>
+  </tr>
+  </table>
+
+</td>
+<td rowspan="2" class="tdc" style="white-space: nowrap; font-size: 90%;">
+
+  <table summary="">
+  <tr>
+   <td>D<span style="letter-spacing:-.1em;"><sup>2</sup>/<sub>&nbsp;3</sub></span>&nbsp;&nbsp;&times;&nbsp;S<sup>3</sup>
+   </td>
+  </tr>
+  <tr>
+   <td><hr style="width:100%;height:1px;padding:0;margin:0;" />
+   </td>
+  </tr>
+  <tr>
+   <td>I.H.P. &times; &radic;<span style="border-top: thin solid black;">ent.</span>
+   </td>
+  </tr>
+  </table>
+
+</td>
+<td class="tdc" colspan="2">Kirk's system</td>
+<td class="tdc" colspan="2">Coal consumption</td>
+<td class="tdc" colspan="2">Cylinders</td>
+<td class="tdc" colspan="2">Boilers</td>
+<td class="tdc" rowspan="2">Working Pressure</td>
+</tr>
+<tr>
+<td class="tdc">Length of entrance</td>
+<td class="tdc">Angle</td>
+<td class="tdc">Per day</td>
+<td class="tdc">Per I.H.P.</td>
+<td class="tdc">Diameter</td>
+<td class="tdc">Stroke</td>
+<td class="tdc">Heating surface</td>
+<td class="tdc">Bar surface</td>
+ </tr>
+<tr>
+<td>&nbsp;</td>
+<td class="tdc">ft. in.</td>
+<td class="tdc">ft. in.</td>
+<td class="tdc">ft. in.</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td class="tdc">Ins.</td>
+<td class="tdc">Ins.</td>
+<td>&nbsp;</td>
+<td>&nbsp;</td>
+<td class="tdc">Lbs.</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">City of Rome</td>
+<td class="tdc">542 &nbsp; 6</td>
+<td class="tdc">52 &nbsp;  0</td>
+<td class="tdc">21  5&frac12;</td>
+<td class="tdc">1031</td>
+<td class="tdc">11,230</td>
+<td class="tdc">11,890</td>
+<td class="tdc">18.235</td>
+<td class="tdc">.649</td>
+<td class="tdc">.925</td>
+<td class="tdc">.702</td>
+<td class="tdc">255</td>
+<td class="tdc">201.3</td>
+<td class="tdc">161.27</td>
+<td class="tdc" style="white-space: nowrap;">8&deg; 29'</td>
+<td class="tdc">185</td>
+<td class="tdc">2.2</td>
+<td class="tdc" style="white-space: nowrap;">{3 @  46 }<br/>{3 @  86 }</td>
+<td class="tdc">72</td>
+<td class="tdc">29,286</td>
+<td class="tdc">1398</td>
+<td class="tdc">90</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Normandie</td>
+<td class="tdc">459  4</td>
+<td class="tdc">49  11</td>
+<td class="tdc">19  9&frac34;</td>
+<td class="tdc">892</td>
+<td class="tdc">7,975</td>
+<td class="tdc">6,959</td>
+<td class="tdc">16.66</td>
+<td class="tdc">.614</td>
+<td class="tdc">.901</td>
+<td class="tdc">.681</td>
+<td class="tdc">265</td>
+<td class="tdc">219.5</td>
+<td class="tdc">146.41</td>
+<td class="tdc">8&deg; 44'</td>
+<td class="tdc">148</td>
+<td class="tdc">2</td>
+<td class="tdc" style="white-space: nowrap;">{3 @ 35 7/16}<br />{3 @ 74 7/8}</td>
+<td class="tdc">67</td>
+<td class="tdc">21,404</td>
+<td class="tdc">756</td>
+<td class="tdc">85.2</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Furnessia</td>
+<td class="tdc">445  0</td>
+<td class="tdc">44   6</td>
+<td class="tdc">22  2&frac12;</td>
+<td class="tdc">893</td>
+<td class="tdc">8,578</td>
+<td class="tdc">4,045</td>
+<td class="tdc"><span class="tfa">1</span>  14</td>
+<td class="tdc">.682</td>
+<td class="tdc">.903</td>
+<td class="tdc">.755</td>
+<td class="tdc">284</td>
+<td class="tdc">273</td>
+<td class="tdc">108.7</td>
+<td class="tdc">10&deg; 28'</td>
+<td class="tdc">97</td>
+<td class="tdc">2.2</td>
+<td class="tdc">49-100</td>
+<td class="tdc">66</td>
+<td class="tdc">10,396</td>
+<td class="tdc">440</td>
+<td class="tdc">90</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Arizona</td>
+<td class="tdc">450  0</td>
+<td class="tdc">45   1&frac12;</td>
+<td class="tdc">18  9</td>
+<td class="tdc">758</td>
+<td class="tdc">6,415</td>
+<td class="tdc">6,300</td>
+<td class="tdc">17</td>
+<td class="tdc">.589</td>
+<td class="tdc">.895</td>
+<td class="tdc">.658</td>
+<td class="tdc">269.2</td>
+<td class="tdc">217</td>
+<td class="tdc">153.79</td>
+<td class="tdc">7&deg; 30'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  62    }<br />{2 @  90    }</td>
+<td class="tdc">66</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">90</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Orient</td>
+<td class="tdc">445  0</td>
+<td class="tdc">46   0</td>
+<td class="tdc">21  4&frac12;</td>
+<td class="tdc">904</td>
+<td class="tdc">7,770</td>
+<td class="tdc">5,433</td>
+<td class="tdc">15.538</td>
+<td class="tdc">.621</td>
+<td class="tdc">.919</td>
+<td class="tdc">.676</td>
+<td class="tdc">270.8</td>
+<td class="tdc">225</td>
+<td class="tdc">144.17</td>
+<td class="tdc">8&deg; 21'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  60    }<br />{2 @  85    }</td>
+<td class="tdc">60</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">75</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Stirling Castle</td>
+<td class="tdc">420  0</td>
+<td class="tdc">50   0</td>
+<td class="tdc">22  3</td>
+<td class="tdc">990</td>
+<td class="tdc">7,600</td>
+<td class="tdc">8,396</td>
+<td class="tdc">18.4</td>
+<td class="tdc">.569</td>
+<td class="tdc">.889</td>
+<td class="tdc">.639</td>
+<td class="tdc">286.8</td>
+<td class="tdc">233.7</td>
+<td class="tdc">151.3</td>
+<td class="tdc">8&deg; 22'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  62    }<br />{2 @  90    }</td>
+<td class="tdc">66</td>
+<td class="tdc">21,161</td>
+<td class="tdc">787</td>
+<td class="tdc">100</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Elbe</td>
+<td class="tdc">420  0</td>
+<td class="tdc">44   9</td>
+<td class="tdc">20  0</td>
+<td class="tdc">807</td>
+<td class="tdc">6,350</td>
+<td class="tdc">5,665</td>
+<td class="tdc">16.571</td>
+<td class="tdc">.591</td>
+<td class="tdc">.901</td>
+<td class="tdc">.655</td>
+<td class="tdc">275.5</td>
+<td class="tdc">229</td>
+<td class="tdc">144.6</td>
+<td class="tdc">7&deg; 56'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  60    }<br />{2 @  85    }</td>
+<td class="tdc">60</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Pembroke Castle</td>
+<td class="tdc">400  0</td>
+<td class="tdc">42   0</td>
+<td class="tdc">17  0</td>
+<td class="tdc">648</td>
+<td class="tdc">5,130</td>
+<td class="tdc">2,435.8</td>
+<td class="tdc">13.25</td>
+<td class="tdc">.623</td>
+<td class="tdc">.623</td>
+<td class="tdc">.692</td>
+<td class="tdc">284</td>
+<td class="tdc">258</td>
+<td class="tdc">122.9</td>
+<td class="tdc">8&deg; 49'</td>
+<td class="tdc">44</td>
+<td class="tdc">1.7</td>
+<td class="tdc">43 and 86</td>
+<td class="tdc">57</td>
+<td class="tdc">7,896</td>
+<td class="tdc">288</td>
+<td class="tdc">99</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Umbria and Etruria</td>
+<td class="tdc">500  0</td>
+<td class="tdc">57   0</td>
+<td class="tdc">22  6</td>
+<td class="tdc">1090</td>
+<td class="tdc">9,860</td>
+<td class="tdc">14,321</td>
+<td class="tdc">20.18</td>
+<td class="tdc">.538</td>
+<td class="tdc">.896</td>
+<td class="tdc">.637</td>
+<td class="tdc">260</td>
+<td class="tdc">191.8</td>
+<td class="tdc">184</td>
+<td class="tdc">6&deg; 52'</td>
+<td class="tdc">315</td>
+<td class="tdc">2.1</td>
+<td class="tdc">{1 @  71    }<br />{2 @ 105    }</td>
+<td class="tdc">72</td>
+<td class="tdc">38,817</td>
+<td class="tdc">1606</td>
+<td class="tdc">110</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Aurania</td>
+<td class="tdc">470  0</td>
+<td class="tdc">57   0</td>
+<td class="tdc">20  0</td>
+<td class="tdc">1020</td>
+<td class="tdc">8,800</td>
+<td class="tdc">8,500</td>
+<td class="tdc"><span class="tfa">1</span>  17.5</td>
+<td class="tdc">.575</td>
+<td class="tdc">.942</td>
+<td class="tdc">.632</td>
+<td class="tdc">266</td>
+<td class="tdc">204.6</td>
+<td class="tdc">170</td>
+<td class="tdc">8&deg; 38'</td>
+<td class="tdc">215</td>
+<td class="tdc">2.2</td>
+<td class="tdc">{1 @  68    }<br />{2 @  91    }</td>
+<td class="tdc">72</td>
+<td class="tdc">23,284</td>
+<td class="tdc">1001</td>
+<td class="tdc">&mdash;</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">America</td>
+<td class="tdc">441  8</td>
+<td class="tdc">51   3</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">6,500</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc"><span class="tfa">1</span>  17.8</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">185</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  63    }<br />{2 @  91    }</td>
+<td class="tdc">66</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">882</td>
+<td class="tdc">&mdash;</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Oregon</td>
+<td class="tdc">501  0</td>
+<td class="tdc">54   2</td>
+<td class="tdc">23   8</td>
+<td class="tdc">1150</td>
+<td class="tdc">11,000</td>
+<td class="tdc">13,300</td>
+<td class="tdc">18.3</td>
+<td class="tdc">.599</td>
+<td class="tdc">.849</td>
+<td class="tdc">.67</td>
+<td class="tdc">227.9</td>
+<td class="tdc">190</td>
+<td class="tdc">164.3</td>
+<td class="tdc">9&deg; 39'</td>
+<td class="tdc">310</td>
+<td class="tdc">2.2</td>
+<td class="tdc">{1 @  70    }<br />{2 @ 104    }</td>
+<td class="tdc">72</td>
+<td class="tdc">38,047</td>
+<td class="tdc">1428</td>
+<td class="tdc">110</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Servia</td>
+<td class="tdc">515  0</td>
+<td class="tdc">52   0</td>
+<td class="tdc">23  3½</td>
+<td class="tdc">1046</td>
+<td class="tdc">10,960</td>
+<td class="tdc">10,300</td>
+<td class="tdc"><span class="tfa">1</span>  16.9</td>
+<td class="tdc">.610</td>
+<td class="tdc">.862</td>
+<td class="tdc">.71</td>
+<td class="tdc">231</td>
+<td class="tdc">192</td>
+<td class="tdc">145.3</td>
+<td class="tdc">10&deg; 42'</td>
+<td class="tdc">205</td>
+<td class="tdc">2</td>
+<td class="tdc">{1 @  72    }<br />{2 @ 100    }</td>
+<td class="tdc">78</td>
+<td class="tdc">27,483</td>
+<td class="tdc">1014</td>
+<td class="tdc">&mdash;</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Scotia, P.S.</td>
+<td class="tdc">369  0</td>
+<td class="tdc">47   6</td>
+<td class="tdc">19  9</td>
+<td class="tdc">867</td>
+<td class="tdc">6,000</td>
+<td class="tdc">4,632</td>
+<td class="tdc" style="white-space: nowrap;"><span class="tfa">1</span>  14.31</td>
+<td class="tdc">.605</td>
+<td class="tdc">.92</td>
+<td class="tdc">.65</td>
+<td class="tdc">208.9</td>
+<td class="tdc">186</td>
+<td class="tdc">126.8</td>
+<td class="tdc">13&deg; 21'</td>
+<td class="tdc">168</td>
+<td class="tdc">3.4</td>
+<td class="tdc">&nbsp;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Alaska</td>
+<td class="tdc">500  0</td>
+<td class="tdc">50   0</td>
+<td class="tdc">21  0</td>
+<td class="tdc">949</td>
+<td class="tdc">9,210</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">.614</td>
+<td class="tdc">.904</td>
+<td class="tdc">.679</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">160.23</td>
+<td class="tdc">8&deg;  2'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  68   }<br />{2 @ 100    }</td>
+<td class="tdc">72</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">100</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Aller</td>
+<td class="tdc">438  0</td>
+<td class="tdc">48   0</td>
+<td class="tdc">21  0</td>
+<td class="tdc">907</td>
+<td class="tdc">7,447</td>
+<td class="tdc">7,974</td>
+<td class="tdc">17.9</td>
+<td class="tdc">.590</td>
+<td class="tdc">.899</td>
+<td class="tdc">.656</td>
+<td class="tdc">277</td>
+<td class="tdc">225</td>
+<td class="tdc">150.6</td>
+<td class="tdc">8&deg; 10'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  44   }<br />{1 @  70}<br />{1 @ 100    }</td>
+<td class="tdc">72</td>
+<td class="tdc">22,630</td>
+<td class="tdc">799</td>
+<td class="tdc">150</td>
+</tr>
+<tr>
+<td style="white-space: nowrap;">Ems</td>
+<td class="tdc">430  0</td>
+<td class="tdc">46  10</td>
+<td class="tdc">20  7½</td>
+<td class="tdc">877</td>
+<td class="tdc">7,030</td>
+<td class="tdc">7,251</td>
+<td class="tdc">17.55</td>
+<td class="tdc">.593</td>
+<td class="tdc">.907</td>
+<td class="tdc">.652</td>
+<td class="tdc">273</td>
+<td class="tdc">223</td>
+<td class="tdc">149.4</td>
+<td class="tdc">8&deg; 40'</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">&mdash;</td>
+<td class="tdc">{1 @  62    }<br />{2 @  86    }</td>
+<td class="tdc">60</td>
+<td class="tdc">19,700</td>
+<td class="tdc">780</td>
+<td class="tdc">100</td>
+</tr>
+</table>
+</div>
+
+<p class="tft"><span class="tfa">1</span> Mean speed of a voyage across the Atlantic Ocean.</p>
+
+
+<p>The author next considered the strains to which a ship is exposed, and
+stated that he had before him the calculations for three of the
+largest vessels, two of them of iron and the other of steel; and he
+found, in the case of the iron, the maximum tension on the gunwale
+during the greatest hogging strains likely to be endured at sea would
+not exceed about six tons per square inch, while in the case of the
+steel ship it is only about 6½ tons. These strains are well within the
+limits of safety, and a comparison of the scantlings of these with the
+others justifies the assertion as to their general safety from a
+structural point of view. The sections of these three ships are shown
+in Figs. 1, 2, and 3, with their principal scantlings. It will be seen
+from these sections that the three ships differ materially in their
+mode of construction. In the case of Fig. 1, which represents the City
+of Rome, the largest of the three, it will be seen that the main
+framing of the vessel is entirely transverse, with very heavy keelsons
+in the bottom, and large partial bulkheads or web frames, and the
+outside plating arranged on what is termed the edge to edge principle,
+with a great portion of it double. In the next section, Fig. 2, the
+Servia, which is built of steel, on the other hand, the bottom is
+built on the longitudinal cellular system, the first application, he
+believed, of this system to an Atlantic liner. The plating of the
+Servia is of the usual alternate outer and inner strake system, partly
+double; while the third section, the Oregon, approaches more nearly to
+the ordinary system of framing and plating usually adopted, but it
+will be seen that she was well tied in the bottom by very heavy
+intercostal and plate keelsons, as well as in the top by heavy
+stringers and sheer strakes, with much of her plating doubled, and
+heavy web frames inside. The author next considered the question of
+stability, and went on to deal with the subject of twin screws, and
+stated that the Barrow Shipbuilding Company has done more in the way
+of planning and designing for the adoption of twin screws lately than
+for any other mode of propulsion, and this chiefly for passenger
+steamers. He did not attach much importance to the particular form of
+the blade either in single or twin screws, as he believed so long as
+the disk area, the surface, and pitch were properly adjusted to the
+speed of the vessel, and to enable the engines to use, at the maximum
+speed, just the full quantity of steam that the boilers can make, we
+have got pretty nearly as far as we can get. To fix these dimensions
+of the propeller accurately at the present time, and without further
+knowledge of the action of the screw on the water, was, he thought,
+impossible. All the rules and formul&aelig; are empirical. The best one he
+knew is given in Table IV., due to Mr. Thom, the head of the Barrow
+Company's engineering drawing office, and at present acting manager,
+who has used it for some years in practice. These formul&aelig; are based
+upon the assumption that the area of propeller disk should be
+proportional to the indicated horse power, divided by the cube of the
+speed, and the same with the projected area of the propeller and also
+the surface.</p>
+
+<p class="center">TABLE IV.</p>
+
+<p class="center"><i>Particulars of Propellers and Constants.</i></p>
+
+<div class='center'>
+<table border="0" cellpadding="4" cellspacing="0" summary="">
+<tr><th align='center'>Ship.</th><th align='center'>Length of ship.</th><th align='center'>Disk constant.</th><th align='center'>Proj. surf. constant</th><th align='center'>Feet per minute.<br />Speed of tips.</th></tr>
+<tr><td align='left'>City of Rome.</td><td align='right'>542</td><td align='right'>220</td><td align='right'>69</td><td align='right'>4,715</td></tr>
+<tr><td align='left'>Normandie</td><td align='right'>459</td><td align='right'>250</td><td align='right'>66</td><td align='right'>4,099</td></tr>
+<tr><td align='left'>Furnessia</td><td align='right'>445</td><td align='right'>223</td><td align='right'>69</td><td align='right'>3,654</td></tr>
+<tr><td align='left'>Eden</td><td align='right'>300</td><td align='right'>211</td><td align='right'>64</td><td align='right'>3,080</td></tr>
+<tr><td align='left'>Yorouba</td><td align='right'>270</td><td align='right'>213</td><td align='right'>63</td><td align='right'>3,202</td></tr>
+<tr><td align='left'>Taygete</td><td align='right'>260</td><td align='right'>238</td><td align='right'>56</td><td align='right'>3,166</td></tr>
+<tr><td align='left'>Kow-shing</td><td align='right'>250</td><td align='right'>171</td><td align='right'>69</td><td align='right'>3,369</td></tr>
+<tr><td align='left'>S.Y. Monarch</td><td align='right'>152</td><td align='right'>221</td><td align='right'>65</td><td align='right'>4,040</td></tr>
+<tr><td align='left'>S.Y. Aries</td><td align='right'>138</td><td align='right'>179</td><td align='right'>56</td><td align='right'>2,986</td></tr>
+<tr><td align='left'>Twin screw Fenella</td><td align='right'>200</td><td align='right'>244</td><td align='right'>64</td><td align='right'>2,890</td></tr>
+<tr><td align='left'>Twin screw H.M.S. Fearless<a name="FNanchor_3" id="FNanchor_3"></a><a href="#Footnote_3"><span class="tfa">1</span></a></td><td align='right'>220</td><td align='right'>277</td><td align='right'>67</td><td align='right'>5,022</td></tr>
+<tr><td align='left'>Twin screw H.M.S. Iris</td><td align='right'>&mdash;</td><td align='right'>454<a name="FNanchor_7" id="FNanchor_7"></a><a href="#Footnote_7"><span class="tfa">5</span></a></td><td align='right'>135<a href="#Footnote_7"><span class="tfa">5</span></a></td><td align='right'>&mdash;&mdash;</td></tr>
+<tr><td align='left'>Twin screw H.M.S. Iris<a name="FNanchor_4" id="FNanchor_4"></a><a href="#Footnote_4"><span class="tfa">2</span></a></td><td align='right'>300</td><td align='right'>412</td><td align='right'>221</td><td align='right'>&mdash;&mdash;</td></tr>
+<tr><td align='left'>Twin screw H.M.S. Iris<a name="FNanchor_5" id="FNanchor_5"></a><a href="#Footnote_5"><span class="tfa">3</span></a></td><td align='right'>300</td><td align='right'>346</td><td align='right'>99</td><td align='right'>4,961</td></tr>
+<tr><td align='left'>Twin screw H.M.S. Iris<a name="FNanchor_6" id="FNanchor_6"></a><a href="#Footnote_6"><span class="tfa">4</span></a></td><td align='right'>300</td><td align='right'>439</td><td align='right'>82</td><td align='right'>5,309</td></tr>
+</table></div>
+
+
+<div class="tft">
+
+<p><br /><a name="Footnote_3" id="Footnote_3"></a><a href="#FNanchor_3"><span class="tfa">1</span></a> Estimated with a speed of 17.5 knots and 3,370 I.H.P.</p>
+
+<p><a name="Footnote_4" id="Footnote_4"></a><a href="#FNanchor_4"><span class="tfa">2</span></a> With the first propeller at the estimated speed of 17.5
+knots and 7,000 I.H.P.</p>
+
+<p><a name="Footnote_5" id="Footnote_5"></a><a href="#FNanchor_5"><span class="tfa">3</span></a> With four bladed modified Griffith's on actual trial.</p>
+
+<p><a name="Footnote_6" id="Footnote_6"></a><a href="#FNanchor_6"><span class="tfa">4</span></a> With two bladed modified Griffith's on actual trial.</p>
+
+<p><a name="Footnote_7" id="Footnote_7"></a><a href="#FNanchor_7"><span class="tfa">5</span></a> Constants obtained from first propeller calculated from a
+speed of 18.5 knots and 7,500 I.H.P.</p>
+
+<div class="center">
+<table summary="layout">
+<tr>
+<td>Disk constant = </td>
+<td align="center"><span class="underline">Area of propeller disk × speed of ship in knots.&sup3;</span><br />I.H.P.</td>
+</tr>
+<tr><td>Projected area of constants</td>
+<td><span class="underline">Projected area of propeller × speed of ships in knots.&sup3;</span><br />I.H.P.</td></tr>
+</table>
+</div>
+
+<p>&nbsp;&nbsp;Expanded area constants may be obtained and used in the same way.</p>
+</div>
+
+<p>The discussion which followed was opened by Mr. Holt. He said that if
+they were to have greater speed on the Atlantic, there was one point
+which was not alluded to in the paper, and that was the total
+abolition of cargo on board the great passenger steamers. If vessels
+were built solely for passenger traffic, they would be able to insure
+greater speed by reason of the greater slightness in build and the
+additional space at the command of the designer. The existing Atlantic
+express steamer was far too heavy, and might, if cargo was dispensed
+with, be made with finer lines and more yacht-like. He looked on the
+proposition to fit such vessels with longitudinal bulkheads with great
+fear. If a collision took place&mdash;such, for example, as that which sunk
+the Oregon&mdash;water would get access to one side only of the ship, and
+it was not at all improbable that if a sea was on, she would turn
+right over. At all events, very serious risk would be involved.</p>
+
+<p>Mr. W.H. White, Chief Constructor to the Admiralty, said the question
+of twin screw propulsion was one of special interest to himself, and
+had been so for many years. In 1878 he dealt with it as fully as he
+then could on the basis of the Admiralty data, and he then ventured to
+say everything in favor of twin screws that Mr. John had said in his
+paper. If greater power than that now used in such a ship as the
+Etruria, for example, were demanded, two screws must be used. Good as
+are the results obtained with the Etruria, it was by no means certain
+that still better might not be had. If she had been fitted with two
+screws instead of one, very great advantage would be gained by the
+greater submergence of the twin screws, as thus racing would be almost
+wholly prevented.</p>
+
+<p>Mr. Calvert urged that more attention should be devoted to studying
+the relative values of different portions of the propeller.</p>
+
+<p>The sitting was then suspended. In the afternoon, as we have already
+stated, the members visited the steamship Germanic on the invitation
+of Messrs. Ismay, Imrie &amp; Co., subsequently proceeding to Messrs. Cope
+Brothers' tobacco works, and thence to the exhibition, where the
+dinner of the Institution took place in the evening.</p>
+
+<p>On Friday morning no paper was read; some official business was
+transacted, and this being done, the discussion on Mr. John's paper
+was resumed.</p>
+
+<p>Mr. Biles remarked that there were many advantages in the use of twin
+screws which had not been sufficiently taken into account. When a ship
+with twin screws was being handled in dock there was greater
+maneuvering power, and therefore less liability for the ship to come
+in contact with the walls, although, if she did so, there would be
+greater probability of damage to the propellers. He thought means
+could be easily devised of protecting the screws when the ship was in
+dock. Another of the incidental advantages connected with twin screws
+was that smaller engines and smaller propellers were required, and
+therefore they might run them at a higher speed. They would also get
+lighter machinery with twin screws, and there would be less liability
+to have bad castings and forgings in the smaller engines, and of
+course the cost would be less.</p>
+
+<p>With respect to the question of the middle line bulkheads, he could
+not quite agree with Mr. John as to the great advantages of them in a
+big passenger steamer. He thought there would be greater difficulty in
+managing a ship so built if she was in danger of sinking. Increased
+subdivision in a longitudinal direction was a very desirable thing,
+and almost necessary for a condition of immunity from sinking. In
+future Atlantic steamers longitudinal bulkheads should be placed not
+in the middle line, but nearer the sides of the ships, and they should
+recognize the fact that they had engines and boilers in different
+compartments, and make arrangements whereby the ship would still
+float, although the doors in these compartments were kept open. The
+proper way to arrive at that was to have a ship with great beam, and
+to have two longitudinal bulkheads at considerable distances from the
+sides of the ship, subdivided as completely as possible, both under
+and above water, so that, even supposing they got water into the space
+between one bulkhead and the side of the ship, they would have
+sufficient buoyancy in the other parts of the ship to keep her afloat.
+Broad ships must necessarily mean deep ships, in order to have comfort
+at sea. They were limited in length, and first came the question how
+many passengers they wanted to carry. The experience of a ship like
+the America&mdash;which was only 400 ft. in length&mdash;showed it was not
+necessary to go to great length to have great speed. A ship of 400 ft.
+to 430 ft. in length, 65 ft. of beam, and with a depth of 45 ft.,
+would be a ship of proper dimensions for the Atlantic trade, and he
+believed it quite possible to build a vessel of special construction
+of about 7,000 tons gross register which should steam with less
+consumption of coal than the Umbria and Etruria at a rate of 22 knots,
+crossing the Atlantic from Liverpool to New York in six days. He
+thought that was likely to be the vessel of the future, and that it
+would be quite as commercially successful as the Umbria or Etruria.</p>
+
+<p>Mr. J. Campbell remarked that at present the great American liners had
+only the ordinary compound engines, and he thought that, instead of
+converting them to triple expansion, they should take a step further
+at once, and adopt quadruple expansion engines. This class of engines
+was being very successfully built in various parts of the country. He
+should recommend the adoption of a three-crank six-cylinder engine.</p>
+
+<p>Mr. Hamilton did not think it had been demonstrated that greater
+efficiency had been got out of twin screws than out of single screws;
+but there was no doubt they would tend to additional safety.</p>
+
+<p>Mr. Martell said that when they had got satisfactory data, twin screws
+would be adopted for ships requiring great speed; but they had not got
+that data at present.</p>
+
+<p>Admiral Sir John Hay, referring to twin screws as applying to
+sea-going steamers which might be employed for imperial defense, said
+it was quite certain <a name="Page_8956" id="Page_8956"></a>that the defense of their
+extended commerce would always require to be assisted by ships such as
+the Oregon and other magnificent vessels which had been used for that
+purpose on a recent occasion. He believed that for war purposes the
+twin screw was recognized by all naval men as having very many
+advantages. If that were so, it was quite evident that it would be a
+great advantage, under such conditions as occurred at the loss of the
+Oregon, if the compartments could be made completely water-tight; and
+the twin screw, with the separation of the ship longitudinally, gave
+them the very greatest possible protection. They could not trust to
+bulkheads that were only closed occasionally by doors. What was
+required for war purposes was the entire and complete isolation of
+different parts of the ship, having always practically closed
+communications between them.</p>
+
+<p>Mr. John then replied on the general discussion. He was pleased to
+find that they had faith in the future of the twin screw and of
+subdivision. The public had a right to demand greater safety than they
+at present had on the Atlantic, or could have with a single screw.</p>
+
+<p><a name="Footnote_2" id="Footnote_2"></a><a href="#FNanchor_2">1</a></p><div class="note"><p>A paper recently read before the Institution of Naval
+Architects.</p></div>
+
+<hr />
+
+
+
+
+<h2><a name="art08" id="art08"></a>EXAMINATION QUESTIONS IN GENERAL CONSTRUCTION.</h2>
+
+
+<p>The following is a copy of the last examination paper given to
+candidates who are desirous of employment in the constructive
+departments of the municipality of New York:</p>
+
+<p>N.B.&mdash;In case candidate does not remember formula or method of solving
+any problem submitted to him, let him name any work upon the subject
+where such formula or method may be found.</p>
+
+<ol class="q">
+<li>What is civil engineering?</li>
+
+<li>Have you ever pursued a course of study in any educational
+institution, or with any civil engineer, which would fit you for the
+position of assistant engineer? If so, state when and with whom; state
+also, in detail, what experience you have had.</li>
+
+<li>Have you ever had responsible charge of any public work? If so,
+state particulars.</li>
+
+<li>Solve the following according to the algebraic signs:
+<pre>
+     / <span class="overline"><span class="underline">(6-2/7 - 4-5/9) × 8-7/16</span>  ×  67873.367 </span>,
+   \/              4-4/12
+</pre>
+
+and show your work.</li>
+
+
+<li> The population of a certain town in 1880 was 7,095; it having
+increased 25 per cent. in ten years, what was it in 1870? Show your
+work.</li>
+
+<li>How many feet, board measure, in the flooring of a room 20 feet by
+30 feet and 2½ inches thick?</li>
+
+<li>Find value of x and y in the following equations:
+
+<ul>
+<li>2 x + 3 y = 33</li>
+<li>4 x - y = 17.</li>
+</ul>
+</li>
+
+<li>Find value of x in equation x² - x - 40 = 170.</li>
+
+<li>Find value of x in equation
+
+<pre>
+   <span class="underline">a</span> +  / <span class="overline"><span class="underline">a² - x²</span></span> =  <span class="underline">x</span>
+   b  \/     x²      b
+</pre></li>
+
+<li>Explain the meaning of the expression a½ × b¾.</li>
+
+<li>What is a logarithm?</li>
+
+<li>What is the base of the common system?</li>
+
+<li>In making what calculations are logarithms useful?</li>
+
+<li>How do you find the logarithm of a number in a table of
+logarithms?</li>
+
+<li>What are similar triangles?</li>
+
+<li>How are similar triangles proportioned to each other?</li>
+
+<li>The sides of a polygon being prolonged, what is the sum of all the
+exterior angles equal to?</li>
+
+<li>How do you pass the circumference of a circle through three given
+points not in the same straight line?</li>
+
+<li>How do you describe a square in a circle?
+
+<p class="center"><img src="./images/6a.png" alt="" /></p>
+</li>
+
+<li>In the triangle, b being a right angle, what proportion does d b
+bear to a d and d c?</li>
+
+<li>How do you inscribe a regular hexagon in a circle?</li>
+
+<li>What proportion do circumference and areas of circles bear to
+their radii?</li>
+
+<li>How do you find the area of a regular polygon?</li>
+<li>Of an irregular polygon? </li>
+<li>Of a circle?</li>
+<li>How do you find the solid contents of a cylinder?</li>
+<li>Of a wedge? </li>
+<li>Of a pyramid?</li>
+
+<li>Find the contents of the wedge, base 20 feet by 30 feet, height 10
+feet, edge 15 feet.</li>
+
+<li>State the prismoidal formula; would you use it in calculating
+earthwork?</li>
+
+<li>Is a simple question in calculating areas.&mdash;Ed. <i>Eng. News</i>.</li>
+
+<li>How many and what parts of a plane triangle must be given to find
+the rest?</li>
+
+<li>Define the terms sine, co-sine, tangent, and co-tangent.</li>
+
+<li>What are natural sines, co-sines, etc.?</li>
+
+<li>What is a table of logarithmic sines, co-sines, etc.?</li>
+
+<li>Two sides and two angles of a plane triangle being given, how do
+you find the other parts?</li>
+
+<li>When two sides of a plane triangle and their included angles are
+given, how do you find the other parts?</li>
+
+<li>In the right-angled triangle, A B H express algebraically the
+value of the sine, co-sine, tangent, and co-tangent of angle A in
+terms of a, b, and h, they being the altitude, base, and hypothenuse
+of the triangle.</li>
+
+<li>What is the law of gravitation?</li>
+
+<li>Do you understand that there is any difference in the meaning of
+the terms gravitation and gravity?</li>
+
+<li>What is the law of falling bodies?</li>
+
+<li>Express algebraically this law, taking v = velocity of falling
+body; g = acceleration of gravity; and h = height.</li>
+
+<li>What is the center of gravity of a body?</li>
+
+<li>How is it found?</li>
+
+<li>Where is the center of gravity of a homogeneous body whose sides
+are all rectangles?</li>
+
+<li>What is the specific gravity of a body?</li>
+
+<li>What is the standard for solids and liquids?</li>
+
+<li>What for gases?</li>
+
+<li>What laws govern the pressure of liquids at rest?</li>
+
+<li>How do you find the number of gallons of water to the cubic foot?</li>
+
+<li>What is the weight of a gallon of water?</li>
+
+<li>What is the pressure per square inch on the side of a vessel at
+the depth of 10 feet below the surface of the water?</li>
+
+<li>What will be the theoretical volume of discharge per second from a
+reservoir through a pipe 1 foot in diameter, discharging at a depth of
+100 feet below the surface of the water?</li>
+
+<li>How many gallons of water will be discharged through a pipe 1 foot
+in diameter, 328 feet long, head 13½ feet, coefficient of flow =
+0.007?</li>
+
+<li>State how many men are needed to make up a full party for a survey
+of a preliminary line or location of a public work, such as a railroad
+or aqueduct.</li>
+
+<li>State also their several duties.</li>
+
+<li>For what purpose is the magnetic needle used in surveying land?</li>
+
+<li>What is a traverse table and for what used?</li>
+
+<li>How do you set out a circular curved line upon the ground?</li>
+
+<li>If an obstacle occurs to alignment, state how you would overcome
+it upon straight lines, also upon curves.</li>
+
+<li>The radius of a curve being given, and angle of intersection of
+the two tangents, how do you find the length of the tangent from their
+intersection to the beginning of the curve?</li>
+
+<li>Describe an engineer's transit, and name its adjustments.</li>
+
+<li>Describe a Y level, and name its adjustments.</li>
+
+<li>How many kinds of leveling rods do you know of?</li>
+
+<li>State how they are graduated, and how they can be read to the
+1/1000 of a foot.</li>
+
+<li>Show a form of field-book for transit notes used when &quot;running&quot;
+curves, and place thereon notes of a 5 deg. curve for 1,000, with two
+intermediate &quot;set-ups.&quot;</li>
+
+<li>Show a form of level-book, and place therein sufficient figures to
+show your method.</li>
+
+<li>What are cross-sections?</li>
+
+<li>How do you set slope stakes for excavation and embankment?</li>
+
+<li>What is a grade line?</li>
+
+<li>What proportion of the breaking weight of a beam would you
+consider a safe load?</li>
+
+<li>With the load uniformly distributed, what fractional part of the
+whole weight may be considered, in all calculations, as being carried
+at the center?</li>
+
+<li>Suppose a beam supported at both ends, and take w = weight, l =
+length of beam, b = breadth, d = depth, s = breaking weight. Express
+algebraically the value of s in terms of the other quantities.</li>
+
+<li>Sectional area being 36 square inches, which would be the stronger
+section, 6 by 6 or 4 by 9?</li>
+
+<li>Make a design for a pair of rafters, connected by a tie-beam, for
+a roof 30 feet span, showing the dimensions of the several parts and
+the manner of connecting them. State in detail your method of
+obtaining the several dimensions.</li>
+
+<li>How do you apply the principle of the parallelogram of forces in
+determining the strain on the various members of a structure?
+Illustrate graphically.</li>
+
+<li>What should be the thickness at the top and base of a retaining
+wall 15 feet high, built to retain ordinary earth? Show your method of
+obtaining the required dimensions, also a sketch of the wall, showing
+how it should be founded.</li>
+
+<li>A reservoir is to be built, depth of water 10 feet. If the walls
+are built of masonry, find the thickness of the same, and state how
+they should be built. Show your work.</li>
+
+<li>What is an arch, of how many forms, and of what may it be
+constructed?</li>
+
+<li>Can you state how you would find the thickness of an arch of
+stone, span and rise being given?</li>
+
+<li>Define the intrados and extrados of an arch.</li>
+
+<li>Where should the line of resistance to pressure be found in an
+arch in order to retain its stability?</li>
+
+<li>Can you find the thickness of the abutments, the rise and span of
+the arch being given?</li>
+
+<li>In a semicircular arch, where is the horizontal thrust greatest
+and where least?</li>
+
+<li>Name the common kinds of stone used in building.</li>
+
+<li>Define the terms &quot;quarry-faced,&quot; &quot;rough-pointed,&quot; &quot;fine-axed,&quot;
+&quot;bush-hammered,&quot; as applied to the dressing of stone.</li>
+
+<li>Describe &quot;rubble&quot; masonry, &quot;ashlar&quot; masonry, and &quot;broken ashlar&quot;
+masonry.</li>
+
+<li>What are &quot;headers&quot; and &quot;stretchers&quot;?</li>
+
+<li>What should be the proportion of &quot;headers&quot; to &quot;stretchers&quot;?</li>
+
+<li>How would you prepare the foundation for a heavy wall, and how
+deep should it be excavated?</li>
+
+<li>How are walls founded on soft or yielding materials?</li>
+
+<li>Describe a good quality of bricks, and state how you would know a
+good brick from a poor one.</li>
+
+<li>In how many ways is brickwork &quot;bonded&quot; to make good work in heavy
+walls?</li>
+
+<li>What is hydraulic cement, and how many kinds do you know of?</li>
+
+<li>Which do you consider the better quality, Rosendale or Portland,
+and why?</li>
+
+<li>What is mortar composed of, and how mixed?</li>
+
+<li>What kind of sand should be used, and how do you test its quality?</li>
+
+<li>What is the meaning of the term &quot;setting&quot; as applied to cement?</li>
+
+<li>How would you test cement?</li>
+
+<li>What is concrete, of what composed, and in what proportion should
+its ingredients be mixed?</li>
+
+<li>Name the common kinds of wood used in building.</li>
+
+<li>What kind of timber resists decay longest under ground?</li>
+
+<li>How may timber be preserved from decay?</li>
+
+<li>What do you understand by limit of elasticity as applied to a
+beam under strain or pressure? What is meant by the neutral axis of a
+beam?</li>
+
+<li>What is the tensile strength of a good quality of wrought iron
+per square inch?</li>
+
+<li>For what parts of a structure may cast and wrought iron be used
+in reference to tension and compression?</li>
+
+<li>Make a sketch of the form of cast-iron beam best adapted to
+resist a transverse strain.</li>
+</ol>
+
+<hr />
+
+
+
+
+<h2><a name="art13" id="art13"></a>CELEBRATION OF THE FIVE HUNDREDTH ANNIVERSARY OF THE UNIVERSITY OF
+HEIDELBERG, AUGUST, 1886.</h2>
+
+
+<p>The wave of pleasure and enjoyment which flooded everything has
+passed. Heidelberg, usually so quiet, assumed the role of a city of
+the world, and all was bustle and excitement in the streets, which
+were hung with flags and other decorations. The trains constantly
+brought new accessions to the crowd, and gayety and mirth reigned
+supreme.</p>
+
+<p>The dedication of the renovated <i>Aula</i> of the University served as a
+prelude to the festivities of the week. On this occasion a splendid
+flag, embroidered by order of the wives of the faculty of the Academy,
+an equally costly cover for the scepter, and a silver inkstand were
+added to the treasures of the University. Conspicuous among the
+numerous presents received were a richly carved set of furniture&mdash;the
+gift of former students from Switzerland&mdash;and all the publications of
+certain book dealers.</p>
+
+<p>On the afternoon of August 2, the Grand Duke and Duchess arrived in
+Heidelberg, where they were received with much enthusiasm. They
+remained at the modest palace during the time of the jubilee, and
+whenever they appeared they were greeted with expressions of
+patriotism and love. On the evening of the 2d, the
+<i>Oberburgermeister</i>, Dr. Wilckens, extended a hearty welcome to the
+guests who had gathered in the over crowded hall. Vincenz Lachner
+conducted the musical part of the entertainment, which was charming.
+The German Crown Prince arrived early on the 3d, so as to accompany
+his royal cousins to the service in the beautifully decorated
+<i>Heiliggeistkirche</i>, on which occasion Prof. Bassermann spoke with
+great effect. At 11 o'clock, the Court appeared in the <i>Aula</i>, where
+the Grand Duke presided, in virtue of his office of &quot;Rector
+Magnificentissimus.&quot; His address was followed by those of the Crown
+Prince; the <i>Prorector Geheimrath</i>, Dr. Bekker; Edward Zeller, of
+Berlin; Jules Zeller, of Paris; and others. In the evening the
+citizens and strangers were attracted to the <i>Jettenbühel</i> by the
+festival at the castle; from 7:30 until 10 o'clock the nobility held
+court in the <i>Bandhause</i>. The scene was like fairyland, all the
+outlines of the castle were marked by thousands of small lights, and
+the court was lighted by great candelabra. In the ever-increasing
+crowd it was difficult to find a place and to obtain refreshments,
+which were given out in immense quantities by the State.</p>
+
+<p>On the morning of the 4th the people thronged again to the
+<i>Heiliggeistkirche</i> to listen to the address of the <i>Geheimrath</i>, Dr.
+Kuno Fischer, on the fate of the Palatinate and Heidelberg, which was
+preceded and followed by music. After this the participants in the
+festival were brought together by a dinner in the Museum Hall, and
+seldom have speeches so inspired an audience as did those of the Grand
+Duke and the Crown Prince. Never has Heidelberg seen such a
+torch-light procession as that formed by the students in honor of
+their Rector; 3,000 torches lighted him to the City Hall. He thanked
+them, and proposed cheers for the Crown Prince.</p>
+
+<p>On the morning of the 5th there was the presentation of degrees. In
+the afternoon a special train carried four hundred people to
+Karlsruhe, where the royal party held a great reception. The capital
+was decorated with flags, the city parks were lighted with Bengal
+lights, there was music, and a song by the patriotic bard Vierordt was
+sung.</p>
+
+<p>All the splendor and interest shrank into insignificance before the
+grand historical procession on the morning of the 6th, which made a
+lasting impression on the minds of all. The throng of 100,000 people
+watched quietly while the whole history of the Palatinate passed in
+review before them. The procession illustrated this history much
+better than it could have been told by any professor or any book.
+There was not a vacant space to be found, extra trains having brought
+more spectators, and yet everything passed off quietly and without
+accident. In the evening there was a heavy shower, which freshened
+everything, leaving no ill effects to be seen the next morning, which
+was more than could be said of many of those who attended the imposing
+<i>Commerse</i> of the Heidelberg students. As a former student, the Grand
+Duke appeared among the 6,000 visitors at the <i>Commerse</i>, where he
+presided and spoke enthusiastically of the Emperor. Other speeches
+followed, until the conversation became so animated that even Von
+Treitschke, who was received with an ovation, could not be heard. At
+midnight the court retired and the <i>Fidelitas</i> succeeded to their
+rights.</p>
+
+<p>On the 7th the time was spent in excursions and carousing until the
+illumination of the castle began. I never saw an illumination of the
+ruins which could compare in beauty with that of the 7th. The night
+was favorable for fireworks, until finally they were rivaled by the
+moon, numerous boats trimmed with colored lanterns passed along the
+river, there were fire-wheels on the bridge, water fireworks on the
+river, and the quiet was disturbed alternately by the rockets and
+music, and when the names of the Grand Duke and Duchess, crowned with
+brilliant fire, appeared over the water, there was an involuntary
+outburst of enthusiasm. If the old Elector and Electoress could have
+been present at the closing entertainment of the jubilee, on the
+evening of the 8th, they would have rejoiced to see the new life
+brought to the ruins by their successor.&mdash;<i>Illustrirte Zeitung.</i></p>
+
+<hr />
+
+
+
+
+<h3>MANUFACTURE OF LEATHER IN RUSSIA.</h3>
+
+
+<p>From this extensive paper it appears that the matters chiefly used in
+tanning are the bark of the oak, containing from 6.04 to 4.37 per
+cent. of tannin according to the season, that of willows, of the elm,
+and the birch. The leaves of the arbutus, employed in the governments
+of Kasan, Viatka, and Perm, contain about 16 per cent. of tannin,
+while the root of wild sorrel (<i>Rumex acetosella</i>) contains 12 per
+cent. For removing the hair from hides, a lye made from wood ashes is
+still employed. The softening of the leather is effected by means of
+the excrement of dogs, which acts on the leather by means of the
+biliary acid present, which forms with soda a kind of soap. After
+tanning, white Russia leather is coated with a mixture of tar and seal
+oil. Black Russia leather is dyed with alum, extract of sanders, and
+ferrous sulphate. Horse hides are tanned to a great extent for sole
+leather.&mdash;<i>M. Ryloff.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art21" id="art21"></a><a name="Page_8957" id="Page_8957"></a>IMPURITIES IN PHOTOGRAPHIC CHEMICALS, AND
+TESTS FOR SAME.</h2>
+
+
+<p>[Table referred to in a paper read before the Birmingham Photographic
+Society by G.M. JONES, M.P.S.]</p>
+
+
+<table border="1" summary="Substance, Impurities, Tests">
+<tr><th>SUBSTANCE.</th><th>IMPURITIES<br />POSSIBLY PRESENT.</th><th>TESTS.</th></tr>
+<tr><td rowspan="6" valign="top">Ammonia,<br />NH<sub>3</sub> <br />Molec. Wt. 17</td>
+<td>Carbonic acid </td>
+<td>Renders lime-water milky.</td>
+</tr>
+<tr><td>Dissolved solid matter</td>
+<td>Residue left on evaporation.</td>
+</tr>
+<tr><td>Chlorides</td>
+<td>After acidulating with nitric acid, it gives a precipitate with silver nitrate, which after washing is readily soluble in ammonia and reprecipitated by nitric acid.</td>
+</tr>
+<tr><td>Sulphates</td>
+<td>After acidulating with nitric acid, it gives a precipitate with barium nitrate.</td>
+</tr>
+<tr><td>Lime</td>
+<td> A white precipitate with oxalate of ammonium.</td>
+</tr>
+<tr><td>Lead is often present, derived from the action upon flint glass bottles</td>
+<td>Black precipitate with sulphureted hydrogen.</td>
+</tr>
+<tr><td rowspan="4" valign="top">Nitric acid, <br />H, NO<sub>3</sub><br />Molec. Wt. 63</td>
+<td>Traces of sulphuric acid</td>
+<td>After dilution it gives a precipitate with barium nitrate.</td>
+</tr>
+<tr><td>Chlorides</td>
+<td>After dilution it gives a precipitate with silver nitrate.</td>
+</tr>
+<tr><td>Peroxide of nitrogen</td>
+<td>The acid is yellow.</td>
+</tr>
+<tr><td>Iodine may be present if the acid be prepared from sodium nitrate.</td>
+<td>After dilution and cooling it gives a blue color with starch, paste, or mucilage.</td>
+</tr>
+<tr><td rowspan="3" valign="top">Hydrochloric acid,<br />HCl<br />Molec. Wt. 36.5</td>
+<td>Free chlorine</td>
+<td>Liberates iodine from solution of potassium iodide. See also &quot;Chlorides,&quot; nitric acid.</td>
+</tr>
+<tr><td>Sulphuric acid</td>
+<td>As above for nitric acid.</td>
+</tr>
+<tr><td>Perchloride of iron</td>
+<td>Yellow color. Brown precipitate with ammonia added till it smells slightly.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Sulphuric acid,<br />H<sub>2</sub>SO<sub>4</sub><br />Molec. Wt. 98</td>
+<td>Bisulphate of potassium</td>
+<td>Residue on evaporation.</td>
+</tr>
+<tr><td>Sulphate of lead</td>
+<td>Milkiness on dilution. May be completely freed from lead by diluting with three or four times as much water, and allowing to settle.</td>
+</tr>
+<tr><td rowspan="4" valign="top">Acetic acid (glacial),<br />H C<sub>2</sub>H<sub>3</sub>O<sub>2</sub><br />Molec. Wt. 60</td>
+<td>Water</td>
+<td>Does not solidify when cooled to 17° C. (53º F.)</td>
+</tr>
+<tr><td>Sulphurous and hydrochloric acids</td>
+<td>White precipitates with silver nitrate.</td>
+</tr>
+<tr>
+<td>Aldehyde, or volatile tarry matter</td>
+<td>Blackens in the light after adding silver nitrate.</td>
+</tr>
+<tr><td>Organic sulphuric acid</td>
+<td>Smell of garlic.</td>
+</tr>
+<tr><td>Citric acid,<br />H<sub>3</sub>C<sub>6</sub> H<sub>5</sub>O<sub>7</sub>H<sub>2</sub>O <br />Molec. Wt. 210</td>
+<td>Tartaric acid</td>
+<td>Strong solution of potassium. Acetate added to a strong solution of the acid will deposit white
+crystalline bitartrate.</td>
+</tr>
+<tr><td>Pyrogallic acid,<br />(C<sub>6</sub>H<sub>3</sub>)HO<sub>3</sub><br />Molec. Wt. 126</td>
+<td>Metagallic acid</td>
+<td>Black residue, insoluble in water.</td>
+</tr>
+<tr><td>Silver nitrate, AgNO<sub>3</sub><br />Molec. Wt. 170</td>
+<td>Free nitric acid</td>
+<td>Reddens litmus paper. (Neutral silver nitrate does not affect litmus.)</td>
+</tr>
+<tr><td>Potassium carbonate,<br />K<sub>2</sub>CO<sub>3</sub><br />Molec. Wt. 138</td>
+<td>Chlorides and  sulphates</td>
+<td>Same as for ammonia.</td>
+</tr>
+<tr><td rowspan="3" valign="top">Potassium iodide,<br />KI<br />Molec. Wt. 166</td>
+<td>Potassium  carbonate</td>
+<td>A strong solution is alkaline to test paper.</td>
+</tr>
+<tr><td>Sulphates and chlorides</td>
+<td>Same as for ammonia.</td>
+</tr>
+<tr><td>Potassium iodate</td>
+<td>A pretty strong solution becomes yellow from liberation of iodine on addition of dilute sulphuric acid or, better, a strong solution of citric acid.</td>
+</tr>
+<tr><td>Potassium bromide,<br />KBr<br />Molec. Wt. 119</td>
+<td>Similar to  potassium iodide</td>
+<td>See potassium iodide.</td>
+</tr>
+<tr><td>Sodium carbonate,<br />Na<sub>2</sub>CO<sub>3</sub><br />Molec. Wt. 106</td>
+<td>Chlorides and sulphates</td>
+<td>Same as for ammonia.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Sodium chloride,<br />NaCl<br />Molec. Wt. 58.5</td>
+<td>Chloride of calcium<br />Chloride of  magnesium</td>
+<td>Oxalate of ammonium (after
+addition of a little acetic acid) gives a milkiness, or precipitate, indicating calcium; filter this out and add ammonia,
+chloride of ammonium, and phosphate of sodium (clear solutions). A precipitate indicates magnesium. Both the above
+cause dampness in wet weather.</td>
+</tr>
+<tr><td>Sodium sulphate</td>
+<td>As for &quot;sulphates&quot; in ammonia.</td>
+</tr>
+<tr><td>Potassium cyanide, KCN<br />Molec. Wt. 65, and hydrate, KHO<br />Molec. Wt. 56</td>
+<td>Potassium carbonate nearly always present</td>
+<td>Effervescence with dilute acids,  giving off a gas carbonic anhydride, which renders lime-water turbid.</td>
+</tr>
+<tr><td>Kaolin</td>
+<td>Chalk</td>
+<td>Effervescence with dilute acids.</td>
+</tr>
+<tr><td rowspan="3" valign="top">Water, H<sub>2</sub>O<br />Molec. Wt. 18</td>
+<td>Sulphates and chlorides</td>
+<td>Same as for ammonia.</td>
+</tr>
+<tr><td>Calcium carbonate, temporary hardness</td>
+<td>Deposited by boiling. Test as for calcium chloride. See sodium chloride.</td>
+</tr>
+<tr><td>Ammonia, almost always present in distilled and rain water</td>
+<td>Brown coloration, or precipitate with Nessler's reagent.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Gelatine</td>
+<td>Alum</td>
+<td>Ash, sometimes as much as ten per cent.</td>
+</tr>
+<tr><td>Fatty matter</td>
+<td>Separated by precipitation with alcohol. Dissolved out by ether or benzine, and left as a residue
+on evaporation of the solvent.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Ammonium bromide (NH<sub>4</sub>)Br<br />Molec. Wt. 98</td>
+<td>Potassium bromide or other non-volatile bodies</td>
+<td>Leaves a residue when heated.</td>
+</tr>
+<tr><td>Ammonium chloride</td>
+<td>Same as for chlorides in ammonia.</td>
+</tr>
+<tr><td>Pyrogallic acid</td>
+<td>Powdered glass</td>
+<td>Left behind on solution.</td>
+</tr>
+<tr><td>Potassium iodide</td>
+<td>Potassium bromide</td>
+<td>The crystals of bromide are usually more transparent than those of iodide, but no reliance can be placed on this.</td>
+</tr>
+<tr><td>Silver nitrate</td>
+<td>Potassium nitrate, sometimes present in the fused sticks&mdash;not in the crystals</td>
+<td>Will not yield the full quantity of chloride on precipitation with HCl. Gives a purple color to flame.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Sulphuric acid</td>
+<td>When vended as pure, it invariably contains a trace of iron. Common acid is also liable to contain arsenic, selenium, thalium, and many other substances.</td>
+<td>No easy test can be given, as the substances are so numerous some of them volatile, and most require separation from the acid before detection.</td>
+</tr>
+<tr><td>Organic matter, as a piece of straw in a carboy of acid</td>
+<td>Gives a brown color to the acid.</td>
+</tr>
+<tr><td rowspan="2" valign="top">Hydrochloric acid</td>
+<td>Arsenic</td>
+<td>Marsh's test.</td>
+</tr>
+<tr><td>Some yellow samples contain no iron, but an organic salt, and give an alkaline ash on ignition of the residue after evaporation</td>
+<td>Reinsh's test; a small piece of copper foil becomes coated on boiling in dilute acid.</td>
+</tr>
+<tr><td>Calcium chloride</td>
+<td>Calcium hydrate</td>
+<td>The clear filtered solution made with distilled water is alkaline
+to test paper, and gives a precipitate on breathing into it through a tube.</td>
+</tr>
+<tr><td>Pure (?) chemicals  generally</td>
+<td>Broken glass, bits of straw, wood, paper, etc.</td>
+<td>These impurities either float or sink on solution, and may easily be seen.</td>
+</tr>
+</table>
+
+<p class="signature">G.M. JONES, M.P.S.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art12" id="art12"></a>THE CATASTROPHE AT CHANCELADE.</h2>
+
+
+<p>The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885,
+under circumstances that are still fresh in the minds of all, have
+gained a celebrity that renders it unnecessary for us to revert to the
+details of the catastrophe. It will suffice to recall the fact that
+after the accident a private committee was formed for the purpose of
+making an attempt to save the five victims who had been surprised in
+the drifts, and who happened to be in the bottom levels.</p>
+
+<p class="center"><img src="./images/7a.png" alt="FIG. 1.&mdash;PHOTOGRAPHIC EXPLORING APPARATUS." />
+<br /> FIG. 1.&mdash;PHOTOGRAPHIC EXPLORING APPARATUS.</p>
+
+<p>The Lippmann establishment at once offered to make a boring by means
+of which it would be possible to communicate with the galleries in
+which the men were imprisoned, but, despite the most active efforts,
+success was found impossible. In order to satisfy public opinion, the
+committee resolved to bore a well 12 inches in diameter to a depth of
+23 feet, that should permit of reaching the gallery; but this did not
+render the latter accessible. How was it to be seen what had occurred,
+how was it to be made certain that the men were dead, and that all
+hope of rescue must be abandoned? To Mr. Langlois, a Parisian
+photographer, was confided an order to construct a special apparatus
+which might be let down to the bottom of the well by a cord, and
+which, being capable of operating from a distance, should furnish the
+required information through sensitized plates. As may be seen, this
+operation presented peculiar difficulties, although Mr. Langlois was
+enabled to overcome these with much skill.</p>
+
+<p>The photographic apparatus that the ingenious operator constructed was
+contained in a metallic case that could be let down into the bore
+hole. The upper and lower parts of the contrivance were provided with
+incandescent lamps, that could be lighted or extinguished from a
+distance, by means of conductors. The photographic apparatus, properly
+so called, formed of an objective and camera with its sensitized
+plate, was inclosed in a cylinder 3½ inches in diameter. By means of a
+cord drawn at the mouth of the well, the apparatus could be made to
+issue from its vertical sheath, and to pivot around its axis so as
+take views in different directions (Fig. 1).</p>
+
+<p>The entire affair was suspended by twelve-foot iron rods, connected
+with each other end for end.</p>
+
+<p>In using the apparatus, the operating was done in a shanty, which
+served as a dark room. The device was let down into the bore well
+until it touched bottom. At this moment a cord was pulled so as to
+raise the camera, and then a few moments were allowed to elapse in
+order that the apparatus might become immovable. As the objective was
+all the time in the dark, it had neither cap nor shutter, but was
+unmasked from the beginning of the operation.</p>
+
+<p>In order to form an impression on the plate, it was only necessary to
+give light; this being easily done by passing an electric current by
+means of a commutator, so as to light the incandescent lamps. At the
+end of the exposure, the lamps were extinguished and the entire
+apparatus was immersed in darkness. The mean time of exposure was from
+four to five minutes. The apparatus was then hauled up, and the
+negative developed.</p>
+
+<p>The experiments could be renewed as often as necessary, and the
+apparatus be pointed in all directions by turning it a certain number
+of degrees by means of a lever attached to the upper rod. In this way
+were obtained various views of the inaccessible gallery in different
+planes.</p>
+
+<p class="center"><a href="./images/7b.png">
+<img src="./images/7b_th.png" alt="FIGS. 2 AND 3." /></a><br />
+FIGS. 2 AND 3.&mdash;REPRODUCTION OF PHOTOGRAPHS TAKEN IN THE INACCESSIBLE GALLERIES.</p>
+
+<p>We reproduce herewith two of Mr. Langlois' most interesting
+photographs. One of these shows the head of the corpse of a young
+miner whose face stands out in relief against the side of the gallery
+(Fig. 2) the other shows a wheel and a lot of debris heaped up
+pell-mell (Fig. 3).</p>
+
+<p>The series of proofs obtained from small negatives, two inches square,
+gave the completest sort of information in regard to the aspect of the
+subterranean gallery.</p>
+
+<p>The exact place where the boring had been done and the entire and
+broken pillars were recognized, as was also the presence of two
+corpses, thus showing that it was indeed here that it would have been
+necessary to act in order to render aid to the unfortunates.</p>
+
+<p class="center"><img src="./images/7c.png" alt="FIG. 4.&mdash;FAULT THAT CAUSED THE ACCIDENT." /><br /> FIG. 4.&mdash;FAULT THAT CAUSED THE ACCIDENT.</p>
+
+<p>In Fig. 4 is shown the appearance of the great fault that caused the
+accident at Chancelade. It seems to us that this method of
+photographing inaccessible subterranean galleries ought to receive
+numerous applications in the future.&mdash;<i>La Nature.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art25" id="art25"></a><a name="Page_8958" id="Page_8958"></a>SOMZEE'S NEW GAS-BURNERS.</h2>
+
+
+<p>With the object of effecting a very intimate mixture of gas and air,
+and of causing this mixture to reach the point of ignition at as high
+a temperature as possible, M. Leon Somzee, of Brussels, has designed
+several new forms of gas burner, which we now proceed to describe and
+illustrate, from particulars and by drawings kindly supplied by an
+esteemed Brussels correspondent.</p>
+
+<p>The high-power burner shown in Fig. 1 effects perfect combustion of
+the heated mixture of air and gas, which is introduced by the draught
+determined by the arrangement. What chiefly distinguishes this burner
+from others of its class is the fact that it is perfectly suited to
+domestic lighting&mdash;that is to say, it may be arranged for a
+comparatively small consumption of gas, while giving an increase of
+250 per cent. of light.</p>
+
+<p class="center"><img src="./images/8a.png" alt="FIG. 1. and FIG. 2. INCANDESCENT AND HIGH-POWER" />
+<br />FIG. 1. and FIG. 2. <br />INCANDESCENT AND HIGH-POWER BURNERS.</p>
+
+<p>The burner proper is a cage or basket of specially prepared magnesia,
+which yields a warmer tone of light than any obtained hitherto, while
+not requiring so high a temperature before combustion. The cap, made
+of a fire-resisting substance, fits on to a tubular arrangement, R,
+fixed in the upper portion of the body of the burner. The latter is
+supplied by air entering at the cone, O, which terminates the inner
+chamber, K, of the heater, and also by that drawn in by the rising
+column of gas, passing before the orifices, D, which may be regulated
+at will. The small burner, I, which is kept constantly alight, heats
+the central compartment, K, the sides of which transmit heat to the
+gas circulating in the annular casing, L, of the compartment. The
+heated gas passes, by the passage, AA&sup1;, into the space, C, where it
+becomes intimately mixed with the air entering at OP, and also with
+the outer air arriving by the lateral apertures, D.</p>
+
+<p>The <i>vis viva</i> of the jet is diffused through this mixture, which thus
+becomes very intimate, when it penetrates into the tubular
+arrangement, R; combustion now taking place at the top, while the
+refractory cap emits a bright orange light of great steadiness. As it
+is not the flow of gas which determines the entrance of the outer air,
+the former may be used at any pressure&mdash;an advantageous arrangement in
+all respects.</p>
+
+<p>When the small burner, I, in the lower chamber is lighted, the
+products of combustion issue by the orifice, O, of the compartment,
+terminating in a needle like that of the steam injector; and the jet
+draws along the air entering the apertures, PP, above the cone. The
+gas from the pipe, arriving from the annular space, L, fills the two
+lateral pockets shown in dotted lines, and passes through the
+orifices, AA&sup1;, which communicate with the upper chamber of the
+burner. The manner in which it is conveyed thence to the tubular
+arrangement has already been described.</p>
+
+<p>Fig. 2 shows a more simple method of carrying out the same principle,
+and of effecting a considerable saving in gas for a given intensity of
+light. In this form, a wick, T, impregnated with an alkaline earthy
+solution, a few seconds after lighting, affords a focus of white light
+remarkable for its steadiness and brilliancy. A draught of air is
+created by a jet of gas issuing from the hollow needle, B, and passing
+through the vessel, D, which is provided with orifices, O, for the
+entrance of air. The air and gas pass from D into C, whence (after
+their intimate mixture is effected) they pass into the tubular
+arrangement, F, at the top of which combustion takes place.</p>
+
+<p>To regulate the proportions in which the air and gas should mingle, in
+order that the combination should be as intimate as possible, the air
+inlet is made variable by a perforated collar, which permits of the
+orifices, O, being more or less covered. The other proportions of the
+burner&mdash;that is to say, the relative capacity of the two compartments
+and the length of the hollow needle&mdash;are determined by the sectional
+area of the supply-pipe for the gas, which is admitted under moderate
+pressure. Instead of a wire-gauze cap, impregnated with a solution of
+metals or of salts, two fine platinum wires may be used&mdash;one bent into
+the form of a semicircle of about an inch radius, and the other (of
+slightly larger diameter) rolled spirally round the former. When both
+ends of the two wires are connected with the upper portion of the
+tubular arrangement (which in this case is flattened), and the gas is
+ignited at the burner, the metallic arc becomes red hot, and then
+brightly incandescent, emitting a light, less brilliant indeed than
+with magnesia, but of remarkable steadiness.</p>
+
+<p>In this case the production of light is chiefly due to the fact that
+calorific condensation, caused by the use of the helicoidal coil
+surrounding the curved wire, prevents loss of heat in this conductor.
+In these forms of high-power burner, in which the gas is used directly
+for the production of light, the difficulty generally encountered of
+heating the air (present in a larger volume than the gas) has been
+successfully overcome.</p>
+
+<p>Fig. 3 shows the straight and outspread flame burner with a special
+heater. In this arrangement the gas and air are heated before
+combustion, in the compartment, G, directly exposed to the action of a
+small Bunsen burner, R, which is placed (in an opaque glass) in the
+middle of a lyre-shaped figure formed by the two gas-pipes, AA. The
+burner proper consists of two fine annular passages meeting above, and
+emitting a thin annular sheet of gas over the guide, T, made of a
+white refractory substance placed between the two annular jets. The
+object of this guide is to stretch the incandescent sheet of flame,
+composed of several jets, and interpose friction, so as to prevent a
+too rapid ascent of hot gases.</p>
+
+<p class="center"><img src="./images/8b.png" alt="FIG. 3 and FIG. 4 REGENERATIVE BURNERS" /><br />
+FIG. 3 and FIG. 4<br />REGENERATIVE BURNERS WITH INVERTED FLAMES.</p>
+
+<p>The luminous focus is placed within a glass globe, C, mounted on the
+bell, B, of the heater; and the external air enters this bell,
+mingling with the products of combustion of the heating burner, R. The
+portion, D, of the annular passage, B, being made of a highly
+conductive metal, the gas becomes heated in passing to the burner, so
+that both gas and air are raised to the same temperature by the time
+they reach the orifices of the burner. Instead of prolonging the
+gas-pipe to the point of bifurcation, a chamber may be arranged
+immediately below the guide, for the gas and air to become intimately
+mixed by passing through several perforations or wire gauze, receiving
+the excess of heat from the white porcelain guide. The admission of
+gas to both the main and heating burners is regulated by a double
+valve in the pipe; but this arrangement may be used without any
+previous heating of the gas and air.</p>
+
+<p>Fig. 4 shows a similar arrangement to that above described, but
+reversed; the gas and air being previously heated by the products of
+combustion. The two pipes, D, lead the gas to the burner; and the
+incandescent sheet of flame is drawn over a white refractory
+substance, having in its center an orifice through which the hot gases
+rise to the upper portion of the burner. The luminous sheet is spread
+out all the better on account of this return of the flames, which also
+causes the mixture of air and gas to be more complete than when they
+rise directly. The gas escapes horizontally from the orifices of the
+annular burner, B, and mingles with the double current of hot air
+which rushes in above the flame inside the globe, and also below
+through the central portion of the burner.</p>
+
+<p>This lamp throws its light vertically downward; and its illuminating
+power may be increased by providing, above the incandescent sheet, a
+reflector, which diverts into a useful direction the rays thrown
+toward the ceiling. In this arrangement of lamp the flame is
+excessively condensed by its being turned back over the refractory
+guide; and this condensation greatly favors the production of light.
+On the other hand, the combustion of the gas is very perfect, because
+the currents of hot air are thrown directly upon the two sides of the
+flame; and thus the reciprocal action becomes more intense. Lastly,
+the division of the gas into a large number of small jets, in contact
+with which the hot air forms an intimate mixture, causes a greater
+quantity of molecules to partake in the combinations; thus affording a
+proportionate increase of temperature in a given space and time.</p>
+
+<p class="center"><img src="./images/8c.png" alt="FIG. 5. REGENERATIVE BURNER WITH FLAME DEFLECTED" />
+<br />FIG. 5.<br />REGENERATIVE BURNER WITH FLAME DEFLECTED OUTWARD.</p>
+
+<p>Owing to these various circumstances, the final effective duty of this
+burner is advantageous, so that it yields an illuminating power which
+may be put at from 200 to 250 per cent. above that of ordinary
+burners, and about 25 per cent. more than that of other regenerative
+burners. The flame is comparatively steady; the loss due to the
+friction over the white porcelain being almost eliminated, because the
+flame only presses upon the guide for a small portion of its surface,
+and is only spread out to the extent of its dark zone.</p>
+
+<p>The contact between the incandescent sheet of flame and the guide may
+be made as short as desired, and the motion of the gaseous mass be
+directed by a simple button placed in the center of the burner; thus
+giving the form shown by Fig. 5, which, however, differs from the
+previous figure in the fact that the inverted flame is directed
+outward instead of inward.</p>
+
+<p>In this arrangement the button, T, is fixed in the middle of the
+burner, which is made cylindrical and annular, or may consist of a
+ring of small tubes, to which the gas is led by a single pipe; leaving
+the whole &quot;furnace&quot; free for the circulation of air and the products
+of combustion. This is the most recent development of the principle
+patented by M. Somzee in 1882, viz., the formation of an illuminating
+sheet of flame, spread out laterally, while heating the gas and air by
+the products of combustion.</p>
+
+<p>Figs. 6 and 7 show two forms of burner designed especially to give
+economical results with a small consumption of gas. The former is an
+ordinary Argand burner in which hot air is introduced into the upper
+portion of the flame, so as to increase the activity of combustion.
+The luminous sheet of flame is then spread out by a metal disk
+attached to the end of the tube, D, which introduces the air into the
+flame. The outer air becomes heated in its passage through the wire
+gauze, T, which absorbs the heat liberated in the interior of the
+apparatus, and also that which is radiated from the incandescent sheet
+and reflected by a metal shield, P, surrounding the dark part of the
+flame.</p>
+
+<p class="center"><img src="./images/8d.png" alt="FIG. 6. and FIG. 7. TYPES OF ECONOMICAL BURNERS." />
+<br /> FIG. 6. and FIG. 7.<br /> TYPES OF ECONOMICAL BURNERS.</p>
+
+<p>It is the combustion of gas, without the production of useful luminous
+effect inside the shield, which supplies the reflected as well as
+radiated heat to the air. The temperature is still further increased
+by the heat transmitted to the metal portion of the burner, and
+absorbed by the wire gauze, between the close meshes of which the air
+from outside is forced to circulate. Air is admitted inside the flame
+by the chimney, D, placed above the focus, and in which it is raised
+to a high temperature by friction on the upper part of the lamp glass,
+at E, and afterward by its passage through the horizontal portion of
+the bent tube. This tube is impinged upon on the outside by the
+flames, and also by the products of combustion, so that it forms a
+veritable heater of the currents which traverse it.</p>
+
+<p>The introduction of hot air into the central portion of the sheet of
+flame is advantageously supplemented by the spreading out of the flame
+by means of the metal disk, without any possibility of its being
+divided. In this way a more intense heat is obtained, and consequently
+the illuminating power is considerably increased, by the uncombined
+carbon being more readily set free, and being thus kept longer in the
+flame, F. This burner, which may be constructed for a moderate gas
+consumption, gives remarkable results as regards illuminating power
+and steadiness; the abstraction of heat in no way impairing the
+luminosity of the flame, which preserves all its brightness.</p>
+
+<p>The Argand burner with double chimney, shown in Fig. 7, is also an
+economical one for a small consumption of gas. The air admitted to
+both the inside and the outside is raised to a high temperature by
+passing along the spirals of a second and transparent chimney, C&sup1;,
+which surrounds the cylindrical glass, C. The gas itself is heated by
+passing through this hot chamber before reaching the outlet orifices;
+so that the mixture of air and gas takes place under the most
+favorable conditions for their perfect combustion.</p>
+
+<p>The burner is an ordinary Argand, which may terminate below in a small
+chamber for the gas and air to mingle. But this is not necessary; and
+the usual arrangement for mixing the air and gas may be adopted. The
+outer air enters at the top of the central chimney, C and passes into
+the annular space between the two glasses; then descends by the two
+spiral passages, which surround the cylindrical glass and terminate in
+<a name="Page_8959" id="Page_8959"></a>a portion hermetically sealed by a brass plate
+attached to the supply-pipe. All the parts of the burner are thus
+surrounded by a highly-heated atmosphere, especially at the bottom of
+the double chimney; and it will be readily understood that, if the
+branches which lead the gas to the burner are constructed of a highly
+conductive metal, the gas will become heated in its turn by passing
+through passages raised to a high temperature.</p>
+
+<p>The elements are therefore dissociated or separated before their final
+combination; thereby raising the calorific and luminous effect to the
+highest possible degree. Such a burner can, of course, be made as
+small as may be required; thus lending itself admirably to the
+subdivision of illumination. The only precaution required is to
+properly proportion the sectional area of the hot-air passages to the
+radiant surface of the flame, so that the heat does not become too
+intense at the lower portion of the burner.</p>
+
+<p>Fig. 8 shows a double flame burner on the principle of Mr. Heron's,
+but with admission of hot air into the angle formed by the flames. As
+exemplified by Mr. Heron, if two equal batswing burners separately
+give a certain amount of light, on the two flames being brought into
+contact, so as to form a single flame, the luminosity is considerably
+increased, owing to the condensation of heat which results from their
+meeting. The two incandescent sheets are, as it were, forced into one
+another, so as to be combined.</p>
+
+<p class="center"><img src="./images/9a.png" alt="FIG. 8. DOUBLE FLAT-FLAME BURNER" />
+<br />FIG. 8.<br /> DOUBLE FLAT-FLAME BURNER</p>
+
+<p>The high-power burners of Douglass, Coze, Mallet, and others were
+designed on this principle; but its application to uninclosed burners
+was not very satisfactory, because the great cooling down of the inner
+surface of the flames by the strong draught of cold air impaired their
+illuminating power. To counteract this difficulty, M. Somzee adopts a
+heating burner, A, which he places between the two batswing burners,
+B, so that the products of combustion rise in the angle made by the
+two lighting flames, as shown; thus greatly increasing their
+luminosity while maintaining a low consumption of gas.</p>
+
+<p>M. Somzee also raises the illuminating power of an ordinary flat-flame
+burner by causing an obscure effluvium to traverse the dark portion of
+the flame. The effect of this is to increase the activity of
+decomposition in this portion, so that the particles of carbon are the
+more readily set free, and remain longer in suspension in the luminous
+zone. The obscure effluvium may be determined between two points by
+the electric current, or be caused by the heating of an imperfect
+conductor by the current; or, again, it may result from a metal
+conductor heated by the reactions produced in the middle of the flame,
+by separating the cone of matter in ignition. The effect may be
+compared with that obtained by the concentration of two sheets of
+flame; but in this case the sheets are formed by the constituent parts
+of one and the same flame, whence results a more complete utilization
+of the elements composing it. This system is, in fact, a
+simplification of the arrangement adopted in the double-flame burner
+seen in Fig. 8.</p>
+
+<p>Fig. 9 shows a reflecting and regenerative burner with double glass.
+The crown, made of metal polished on both sides, has a circular
+groove, G, for receiving the end of the central chimney, C, and
+presenting an annular aperture by which the products of combustion
+enter. The second glass, C&sup1;, is fastened to the collar of the
+burner carrier, and does not come into contact with the metal crown;
+so as to allow the air to enter from outside for supplying the burner.
+The gas enters by the pipe, T, provided with a cock. This pipe is
+continued to the top of the apparatus, and there spreads out into the
+form of a dome; thus dividing into two compartments the trunconic
+chamber, S¹ S², whence the hot gas returns to the body of the burner,
+B.</p>
+
+<p class="center"><img src="./images/9b.png" alt="FIG 9. REFLECTING AND REGENERATING BURNER." />
+<br />FIG 9. <br />REFLECTING AND REGENERATING BURNER.</p>
+
+<p>On the burner being lighted from below, the products of combustion
+rise in the inner chimney, and enter the heater, which they traverse
+through its entire extent, while impinging against the outside of the
+gas reservoir, to which they give up a large portion of their heat.
+They then pass by the passage, D, into the atmosphere or into a
+chimney. The air necessary for combustion enters at the top of the
+outer globe, and becomes highly heated in its passage through the
+space comprised between the two glasses of the burner. In this way it
+reaches the burner, and forms an intimate mixture with the small jets
+of gas which compose the flame. The gas, on leaving the supply-pipe,
+T, fills one of the compartments, S¹ S², of the heater, and then
+returns by the second compartment, and again descends by the casing of
+the supply-pipe, having its temperature still further raised by
+contact with the internal radiation of the flame.</p>
+
+<p>Under these conditions, all the parts of the burner are supplied by
+heated air, and the combustion becomes very active; thus increasing
+the intensity of the flame, and consequently that of the light
+afforded, while at the same time effecting a saving of 50 per cent. of
+gas. This burner may be made of any size, and for consumptions not
+exceeding that of an ordinary Argand. In fact, the gas is consumed at
+a low pressure, escaping with no greater force than that due to the
+heat of the products of combustion. It is sufficiently expanded on
+coming into contact with the current of hot air, the activity of which
+is regulated by the height of the apparatus, that is to say, by that
+of its two chimneys. The mixture is made in such proportion as to
+obtain from the gas and air as great a degree of luminosity as
+possible. The high temperature of the gas, and the independent means
+of heating the air and gas, constitute the essential principles of
+this burner.&mdash;<i>Journal of Gas Lighting.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art26" id="art26"></a>THE CLAMOND GAS BURNER.</h2>
+
+
+<p class="center"><a href="./images/9c.png"><img src="./images/9c_th.png" alt="THE CLAMOND GAS BURNER." /></a>
+<br /> THE CLAMOND GAS BURNER.</p>
+
+<p>In this burner, which is a French invention, the light is produced by
+burning ordinary coal gas within a basket of magnesia, which is
+thereby brought to a high state of incandescence, and from which a
+white, steady light is radiated. It may be said to consist of three
+different parts. The first and inner part is a central column, B, of
+fireproof material. The second part consists of two concentric
+cylinders placed round the inner column and communicating one with the
+other through the cross cuts, J. The third part is a china cup
+inclosing the other parts, and perforated with a number of holes. The
+gas burns in two different places. From A it passes directly through
+B, at the top of which it branches off through tubes to an annular
+chamber, D, from which it escapes through the openings, <i>a</i>, <i>a</i>, <i>a</i>,
+where combustion takes place. The other combustion occurs within the
+circular space, G, I, between the column and the inner of the two
+surrounding cylinders, through two channels, E E, in the lower part of
+the central column. The gas passes into a circular chamber, F F, and
+escapes through small holes in the upper partition of this chamber,
+where it burns. The product of this combustion passes put into K,
+through the cross cuts, J. The air entering through the holes, H L, of
+the outer china cup passes along the inner of the two concentric
+cylinders, which is heated to redness, and rises highly heated toward
+the upper annular burner, where the gas burns at <i>a</i>, <i>a</i>, <i>a</i>, in small
+separate flames, each entirely surrounded by the hot air. This insures
+perfect combustion of the gas within the basket of magnesia placed
+above, and which is thus brought to a state of incandescence. It will
+be seen from this description how simple and practical the arrangement
+is. It is claimed for the light produced that it will stand comparison
+with the electric light. Like that, it shows colors perfectly true,
+and will enable an observer to distinguish between the most delicate
+shades, allowing of the finest work being executed as by daylight. It
+is, moreover, stated to be perfectly steady. As the Clamond burner can
+be fixed to any gas bracket or lamp now in use, its adoption causes no
+other expense than the cost of the burner itself. There is no
+expensive installation, and when used in combination with the electric
+light, it is claimed that a uniform lighting will be obtainable
+instead of the unpleasant contrast between gas and electricity.
+Another important advantage obtained by the Clamond burner is the
+saving effected in the consumption of gas as compared with the same
+power of light obtained from ordinary burners.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art18" id="art18"></a>A NEW THERMO-REGULATOR.</h2>
+
+
+<p>In the thermo-regulators which have been constructed heretofore, the
+heat has been regulated by the variation in the inflow of gas to the
+heating flame. The apparatus described below, and shown in the
+accompanying cut, taken from the <i>Zeitschrift fur Instrumentenkunde</i>,
+operates on an entirely different principle. The distillation and
+condensation process of a fluid heated to the boiling point in the
+vessel, A, is as follows:</p>
+
+<p class="center"><img src="./images/9d.png" alt="" /></p>
+
+<p>The steam passes first through the pipes, <i>a</i> and <i>c</i>, into the
+serpentine tube, where it is condensed, and then flows through the
+tubes, <i>d</i> and <i>b</i>, back into the vessel, A, if the cock, <i>r</i>, is
+closed, but if the said cock is open, it flows into the receptacle, K.
+When the liquid begins to boil the steam passes freely through the
+tubes, <i>d</i> and <i>b</i>, part passing through the tube, <i>f</i>, out into the
+air, and the other part passing through the open cock, <i>r</i>, to the
+receptacle, K; but the condensed liquid soon closes these passages to
+the steam. At <i>h</i> is an opening for a thermometer, <i>t</i>, and through
+this opening the liquid can be poured into the vessel, A. If the cock,
+<i>r</i>, is kept closed, the volume of liquid in the vessel, A, cannot be
+diminished, and the bath, B, must take the constant and uniform
+temperature of the steam in the vessel, A, as the vessel, B, is heated
+evenly on all sides.</p>
+
+<p>This apparatus can also be used as an air bath, in which case the
+vessel, B, is left empty and closed by a suitable stopper.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art20" id="art20"></a>PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.</h2>
+
+
+<p>The accompanying engraving represents a simple apparatus, which any
+person accustomed to working glass can make for himself, and which
+permits of quickly, and with close approximation, estimating the
+density of a liquid. In addition, it has the advantage of requiring
+but a very small quantity of the liquid.</p>
+
+<p>It consists simply of a straight pipette, A B, to which is affixed
+laterally, at the upper part, a small U-shaped water gauge.</p>
+
+<p>The two branches of the gauge, as well as the pipette itself, are
+graduated into equal divisions. If need be, the graduating may be done
+by simply pasting on the glass strips of paper, upon which a graduated
+scale has been drawn. The zero of the pipette's graduation is exactly
+at the lower extremity, B. The graduation of the two gauge tubes
+extends in both directions from a zero situated near the center. The
+zeros of the two branches must correspond as exactly as possible, so
+that they shall be in the same horizontal plane when the apparatus is
+fixed upon a support. To render the apparatus complete, it only
+remains to adapt, at A, a rubber tube provided with a wire clamp, and
+terminating in a short glass tube for sucking through with the mouth.</p>
+
+<p class="center"><img src="./images/9e.png" alt="PIPETTE FOR TAKING THE DENSITY OF LIQUIDS." /><br /> PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.</p>
+
+<p>For taking the density of a liquid, we plunge the end, B, into it, and
+then suck, and afterward close the <a name="Page_8960" id="Page_8960"></a>rubber tube
+with the clamp. It is essential that this latter shall hold well, so
+that the levels may remain constant.</p>
+
+<p>We now do the reading. Suppose, for example, we read 250.3 mm. on the
+pipette, and 147.7 mm. and 152 mm. on the branches of the gauge.
+Having these data, we loosen the clamp, and allow the liquid to flow.
+On account of capillarity, there remains a drop in B; and of this we
+read the height, say 6 mm. A height 250.5 mm - 6 = 244.5 mm. of liquid
+raised is, then, balanced by a column of water of 147.5 + 152 = 299
+mm.</p>
+
+<p>Now the heights of these two liquids is in the inverse ratio of their
+densities:</p>
+
+<div class="center">
+<table summary="Equation">
+<tr><td><span class="underline"><i>d</i></span><br />1</td><td valign="middle">=</td>
+<td><span class="underline">299.5</span><br />244.5</td>
+<td valign="middle">, whence <i>d</i> = 1.22.</td>
+</tr>
+</table>
+</div>
+
+<p>We obtain <i>d</i> by a simple division.</p>
+
+<p>When the instrument has been carefully graduated, and has been
+constructed by an expert, the accuracy of the first two decimals may
+be relied upon. With a little practice in estimating the last drop, we
+may, in trying to estimate the density of water, even reach a closer
+approximation. In order to measure the height of the drop accurately,
+one should read the maximum height to which the liquid rises between
+the fall of two drops at the moment when the last ones are falling,
+since at that moment, and only at that, can it be ascertained that the
+lower level of the bubble is plane. The error in such reading does not
+reach half a millimeter, and, as a suitable height of the apparatus
+permits of having columns that vary between 13 and 30 centimeters, an
+error of this kind is but 1-300. This is the limit of precision of the
+method.</p>
+
+<p>The clamp might be advantageously replaced by a glass cock, or, better
+still, A might terminate in a rubber bulb; and a lateral tubulure
+might be fixed to the pipette, and be closed with a rubber stopper.</p>
+
+<p>This little apparatus is more easily maneuvered than any of those that
+have hitherto been devised upon the same principle. It is capable also
+of replacing areometers in ordinary determinations, since it permits
+of correcting the error in capillarity that is neglected in
+instruments; and, moreover, one can, when he desires to, easily verify
+for himself the accuracy of the graduation.&mdash;<i>La Nature.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art14" id="art14"></a>USEFUL BAGS, AND HOW TO MAKE THEM.</h2>
+
+<h3>By JOHN T. HUMPHREY.</h3>
+
+
+<p>Since the papers on &quot;Boot and Shoemaking,&quot; in vol. i. of <i>Amateur
+Work</i>, illustrated, I think nothing relating to the leather trades has
+appeared in it; and as there must be many among the readers of this
+magazine who have a desire to dive deeper into the art of manipulating
+leather into the various articles of utility made from that material,
+I will endeavor in the series of articles of which this is the
+commencement to furnish them with the necessary instructions which
+will enable them to do for themselves many things which now are left
+undone, or else have to be conveyed miles to some town where the
+particular business, or something akin to it, is carried on. To the
+colonist and those who live in out-of-the-way districts, it must be a
+matter of great regret to observe articles of use, where the material
+is in good condition, rapidly becoming useless owing to the inability
+of the possessor to do the necessary repairs. Again, it may be that
+the article is completely worn out, and the old proverb that &quot;a stitch
+in time saves nine,&quot; will not be advantageously applied if carried
+out. In that case a knowledge of making new what we require, whether
+in order to replace something already worn out or as an addition to
+our store, must prove beneficial to the thrifty amateur. My object in
+writing these articles is not to deprive the mechanic of any portion
+of his legitimate occupation, but to assist those who live at a
+distance too great to be able to employ him, and who necessarily
+prefer any makeshift to the inconvenience of sending miles, and being
+without for days, an article which might possibly be set right in an
+hour or two.</p>
+
+
+<h3>HOW TO MAKE BAGS.</h3>
+
+<p>The old-fashioned carpet bag (Fig. 1) is still unsurpassed by any,
+where rough wear is the principal thing to be studied. Such a bag, if
+constructed of good Brussels carpeting and unquestionable workmanship,
+will last a lifetime, provided always that a substantial frame is
+used.</p>
+
+<p class="center"><img src="./images/10a.png" alt="FIG 1.&mdash;THE CARPET BAG." /><br /> FIG 1.&mdash;THE CARPET BAG.</p>
+
+<p>Next in order comes the brief bag (Fig. 2), more extensively used than
+any other. For business purposes it is in great favor with bag users,
+being made in a variety of shapes, but all belonging to the same
+class. Here we have the shallow brief, deep brief, eclipse wide mouth,
+imperial wide mouth, excelsior, courier, and many others; but to know
+how to make one will be sufficient for all, the only difference being
+in the cut or style in which they are constructed.</p>
+
+<p class="center"><img src="./images/10b.png" alt="FIG. 2.&mdash;THE BRIEF BAG." /><br /> FIG. 2.&mdash;THE BRIEF BAG.</p>
+
+<p>The cricket bat bag (represented in Fig. 3) is made on the same
+principle throughout as the carpet bag.</p>
+
+<p class="center"><img src="./images/10c.png" alt="FIG. 3.&mdash;THE CRICKET BAT BAG." /><br /> FIG. 3.&mdash;THE CRICKET BAT BAG.</p>
+
+<p>Frames and all necessary fittings required in making bags may be
+purchased of dealers.</p>
+
+<p>Care must be observed in choosing all the pieces necessary for a bag
+from the same pattern carpet, otherwise it will present an unsightly
+appearance when completed. There may be some who would prefer American
+cloth; this is thoroughly waterproof, and has a good appearance for
+some time, but, like all articles of imitation, it has only
+<i>cheapness</i> to recommend it. If cloth is to be used (I mean American
+cloth), let it be the best that can be bought, that which is called
+&quot;double-twill duck,&quot; if possible. As the making is the same whether
+cloth or carpet be used, it will be understood that the instructions
+for making apply to both.</p>
+
+<p>The following tools, which are few and inexpensive, will be required:
+A pair of clams (Fig. 4), cost 1s. 6d.; knife (Fig. 5), 6d.; half
+dozen awl blades, ½d. each; three or four boxwood handles, 1½d. each;
+3 foot rule, 1s.; hammer, 1s.; a packet of harness needles, size 4,
+cost 2½d. (these have blunt points); a bone (Fig. 6) will also be
+required for rubbing the stiffening into place, cost about 3d.; and a
+ball each of hemp and wax for making the sewing threads&mdash;hemp 2½d.,
+wax ½d. For making holes in the bottom where the nails or studs are
+fixed, a large sewing-awl will be required; this will probably have to
+be bought at a saddler's; the other tools can all be obtained at any
+grindery and leather seller's.</p>
+
+<p class="center"><img src="./images/11.png" alt="FIG. 4&mdash;FIG. 11" /><br />
+FIG. 4&mdash;Pair of Clams. FIG. 5&mdash;Knife. FIG. 6&mdash;Bone
+Rubber. FIG. 7&mdash;Method of Measuring Registered Frame: A to A, Top of
+Sides; A to B, Top of Gussets. FIG. 8&mdash;Pattern of Bottom, Showing
+Place of Nails. FIG. 9&mdash;Side Pattern Folded. FIG. 10&mdash;Gusset Pattern
+Folded. FIG. 11&mdash;Pattern for Gusset Stiffening. FIG. 12&mdash;Handle,
+Showing Distance of Rings.</p>
+
+<p>The awl blades mentioned above are of two kinds, and either may be
+used for this work. Those generally used are of a straight diagonal
+shape, making a perforation the shape of a diamond, &lt;&gt; ;  the others are
+perfectly round, tapering gradually to a fine point. To fix them in
+the boxwood handles, place the blade in a vise, leaving the unpolished
+part above the jaws; hold the handle above this, and commence driving
+it down, taking care that the blade is penetrating the middle of the
+handle. Continue tapping the handle until the ferrule reaches the
+polished part of the blade; it will then be in far enough.</p>
+
+<p>A good serviceable pair of clams may be made by taking two staves of a
+good-sized barrel, and cutting about 10 inches off the end of each.
+Screw together with three screws (as in Fig. 4), and shape the
+uppermost ends so that the outsides meet in a sharp ridge along the
+top; this will give a flat surface within the mouth, by which a hold
+of the work may be obtained. A two-inch screw will be long enough for
+the bottom, which must be turned in as tightly as possible; the
+others must not be less than 3 inches, as there will be a space of 1½
+or two inches between the staves at the part where they are inserted.
+Screw these just tight enough to give a good sharp spring to the mouth
+of the clams when they are pressed open; this will insure the work
+being held firmly while being sewn. Sandpaper them over to give a
+smooth appearance, and these will be found as useful as bought ones.</p>
+
+<p>A piece of basil leather will be required for the bottom and welts of
+the bag. This may be purchased at a leather seller's with the tools.
+Cut out the bottom first; the welts may be cut from any narrow pieces.
+These must be cut seven-eighths of an inch wide, then folded over, and
+lightly hammered down. This brings the two edges together, and when
+placed in position, they should lie evenly between the edges of the
+material. A piece of string may be laid in the welt to give it a
+fuller appearance if the leather is very thin.</p>
+
+<p>The following dimensions of bags when made up will enable the maker to
+choose the most useful size:</p>
+
+
+<p class="center">No. 1, 16 by 14 inches; No. 2, 19 by 16 inches;<br />
+No. 3, 21 by 17 inches; No. 4, 24 by 18 inches.</p>
+
+
+<p>The sizes of frames and parts when cut will be as follows:</p>
+
+<div class='center'>
+<table border="0" cellpadding="4" cellspacing="0" summary="">
+<tr><td align='left'>Frame.</td><td align='left'>Sides.</td><td align='left'>Bottom.</td><td align='left'>Gussets.</td></tr>
+<tr><td align='left'>No. 1, 15 inches</td><td align='left'>16½ by 15½</td><td align='left'>16½ by 5½</td><td align='left'>15½ by 5½</td></tr>
+<tr><td align='left'>No. 2, 18 inches</td><td align='left'>19½ by 17½</td><td align='left'>19½ by 6</td><td align='left'>17 by 6</td></tr>
+<tr><td align='left'>No. 3, 20 inches</td><td align='left'>21½ by 18½</td><td align='left'>21½ by 6½</td><td align='left'>18½ by 6½</td></tr>
+<tr><td align='left'>No. 4, 23 inches</td><td align='left'>24½ by 19½</td><td align='left'>24½ by 6½</td><td align='left'>19½ by 6½</td></tr>
+</table></div>
+
+<p>Taking No. 1, 16½ inches will be the length of sides and 15½ inches
+the depth. The gussets are also 15½ deep, the width being 5½, the same
+as the bottom. Take 1½ inches from the depth of these to allow for
+covering the frame, and ½ inch from the length to allow for the seams,
+and we have a bag 16 inches long by 14 inches deep.</p>
+
+<p>And now to commence. Arrange the pieces of carpet on the board, and
+mark off the size of each part required with a piece of chalk or
+pipeclay. By cutting with the carpet, laying the right side up, we
+shall be able to see that the pattern of it will be in the same
+direction on both sides of the bag when made up. We next take the ball
+of hemp, and by pushing the finger through the hole in the center of
+it, drive out the end. To use the hemp from the inside is much the
+best way, because the ball will stand perfectly still, whereas, if
+started from the outside, it will be darting in all directions about
+the floor of the workroom, and entwining itself around any obstacle
+which lies there, unless it is placed securely in a box and drawn out
+through a hole in the center of lid.</p>
+
+<p>A hook must be fixed in some convenient place to make the waxends on,
+or, as they are called in the trade, &quot;threads,&quot; which term it will be
+as well to call them by here; thus a <i>four-cord thread</i> means a thread
+or waxend containing four strands of hemp, a six-cord contains six
+strands, and so on. One of the greatest difficulties for the amateur
+is to produce a well-formed thread. He generally finds it thicker a
+few inches from the point than at any other part. These are known in
+the trade as bull-necked threads; and as the mechanic finds it
+difficult to use them when his employer starts a new apprentice and
+gives him this job for the men, I must impress on the worker here the
+necessity of making them as perfect as possible. It would be as well
+if a little practice was given at breaking the hemp in the way which
+produces good points. Better waste a few yards of hemp than be
+compelled to abandon a thread after making only a few stitches with
+it.</p>
+
+<p>Gripe the hemp firmly between the thumb and forefinger of the left
+hand, leaving about eight or nine inches hanging loosely down; lay
+this over the thigh of the right leg, and with the right hand rub it
+in a downward direction, which will cause the twisted strand to
+loosen. One good stroke should be sufficient; if not, it must be
+repeated until the fibers forming the strand are quite loosened. By
+holding it close to the end with the right hand, and giving it a jerk
+with the left, the fibers will break, and the ends of the strands
+formed in this way are placed at a little distance one above another,
+which, when twisted, form a smooth, tapering point.</p>
+
+<p>To cast off a thread the proper way is to stand at a distance of about
+three feet from the hook previously mentioned, and by holding the end
+of the hemp in the left hand, pass it over the hook and bring it down
+with the right, then holding with the left and breaking as above. When
+sufficient strands to form the thread have been broken off, carefully
+examine the points to see that they taper properly, and have no lumps
+in them. Rub the wax up and down a few times, so that the thread may
+be properly waxed on that portion which will be inside when twisted.
+Hold the two ends in the left hand, and with the right roll each end
+separately down the right leg a sufficient number of times to twist
+the thread throughout. Judgment will be required in this operation, or
+the thread will be a constant source of trouble if it is over-twisted.
+Wax it again, and then it is ready for use. See that the points are
+well waxed, then take a needle and pass the point of the thread
+through the eye until it nearly reaches that part which would stop its
+progress.</p>
+
+<p>It must now be turned down on to the thicker portion and carefully
+twisted. Smooth it down, then take the other end of thread and another
+needle, and fasten it on in the same way. In selecting the awl to be
+used, do not take a very large one. The hole should be just large
+enough for the thread to require a slight pull to get it through.</p>
+
+<p>To commence sewing take one side and a gusset and place them evenly
+together, the right side of the material being inside, and fix them in
+the clams. Slip the welt as previously described between the edges,
+and pass the awl through the lot. Drive it perfectly straight, as upon
+this chiefly depends a nice seam when turned. Draw out the awl, and by
+following the point, pass up the bottom needle with the left hand.
+This should be taken by the thumb and forefinger of the right hand and
+the thread pulled through half its length, so forming a thread of
+equal length on each side. Make another hole with the awl about
+one-third of an inch from the first. This gives the length of stitch.
+Pass up the bottom needle as before into the right hand, the top
+needle descending to the bottom immediately after. Take hold of this
+with the left hand and pull through the threads simultaneously top and
+bottom, until the extremity on each side lies on and forms the stitch.
+Be careful that in pulling in the latter part each thread closes at
+the same time, thereby preventing a crooked seam. Repeat until the
+seam is finished, then take the other gusset and place in position.
+Sew this, then take the other side of bag and sew to the gussets. You
+will then have something in the shape of a bag, minus the bottom. Take
+this next, and fix each corner to one of the seams previously made,
+and stitch it carefully round, placing a welt in as before. At the end
+of each seam a stitch or two back should be taken or the thread tied
+over to prevent it opening.</p>
+
+<p>The outside of the bag being inward, it must now be turned previous to
+stiffening and framing. The turning is done by placing the bag over
+the left arm, and with the right hand commence pushing in one of the
+corners, then the opposite one until that end is reversed. Then serve
+the other end in a similar manner, and smooth each seam along.</p>
+
+<p>We now take a piece of stout millboard (an old ledger book cover will
+do if large enough), or, if purchased with the frame, ask for a two
+pound board: this will cost about 4d., and be sufficient for several
+bags. Cut it quarter of an inch less than the bottom all round, and
+see that it fits before gluing it in. To do this, place one end within
+the seams at one end of the bag, and by lifting it in the middle press
+in the other, when the stiffening will lie within the four seams at
+the bottom. Having fitted it satisfactorily, take it out again and
+glue it well with some good hot glue. This must be neither too thick
+nor too thin. The best way to prepare it is to lay some glue in cold
+water for twelve hours. It will absorb sufficient water in that time,
+and can be boiled up without any further preparation. The quicker it
+is fixed after the glue is put on the better. A brush similar to a
+paint brush will be the best to apply it with, and need not cost more
+than 6d. After the gluing, lay it aside for a few hours to allow it to
+thoroughly set, during which time the making of the handles can be
+proceeded with. On some bought bags these are very common, and seldom
+last more than a few months; the usual plan being to take a piece of
+rope about the size of a clothes line and roll <a
+name="Page_8961" id="Page_8961"></a>a piece of brown paper round it, covering it
+afterward with a piece of basil leather.</p>
+
+<p>Procure two pieces of brown harness leather&mdash;the shoulder of the hide
+is most suitable&mdash;from a saddler, 11 inches long by 1-1/8 inches wide,
+round the four ends, and make a compass mark 1/8 of an inch from the
+edge all round for the stitching. Take a piece of line as above, and
+place within the leather, which most likely will have to be damped to
+make it draw round easier. Leave 1½ inches from each end for sewing to
+the bag, the line also being so much less than the full length of the
+handles. Having sewn them, flatten the ends and bend the handles into
+a semicircular shape, and leave them to dry.</p>
+
+<p>By this time the glue holding the stiffening to the bottom of the bag
+will be set, so the next move will be to put in the studs or nails.
+Take the largest size awl and make five punctures through the bottom,
+about three-quarters of an inch from each corner and one in the
+center, as in Fig 8; push the nails through and turn down each of the
+two claws in an opposite direction, tap them with a hammer to make
+them lie closer, and also to prevent them from becoming loose. This
+done, we next take the frame and remove the key-plate from it.</p>
+
+<p>Fold the sides of the bag well over the frame, so that the stitching
+will get a good hold of the part that goes inside. Put a stitch
+through at each corner to hold it, and see that it sets perfectly true
+on the frame. A space is left between the two plates of iron forming
+the frame, which allows of the bag being sewn through it. Fix the
+key-plate by riveting inside. Sew the bag from one corner of frame to
+the other corner on each side, leaving the gussets unstitched. It is
+now ready for the lining. Let this be good, as it will greatly add to
+the durability of the bag if strong. Coarse linen at 8d. to 10d. per
+yard is the best material for this purpose. The sides and bottom may
+be cut in one piece; the length of this will be twice the depth of one
+side of carpet (less the part which folds over the frame) and the
+width of the bottom. The width of this piece throughout to be a half
+inch less than the outsides were cut. The gusset lining will want to
+be the same width as the gusset, but an inch less in length will do.
+The seams of the lining may be stitched with an ordinary household
+sewing machine if good thread is used. When made, place the lining
+inside the bag, see that it is well down at the bottom, turn in the
+top edge all round to the required size, and fix in as follows: Take a
+long carpet needle and a length of thread, pass the needle through the
+lining at the folded ridge and bring it up again through the same at a
+distance of an inch or so. This forms a stitch within the lining; pass
+the needle through one of the stitches made in sewing in the frame and
+repeat as before, carefully observing that the lining falls into its
+proper place as it is being sewn in. Continue in this way until the
+two sides are done, leaving only the gussets and gusset lining to be
+united. This is done by folding the edges inward and sewing them
+together, the frame joints moving freely between the gussets and
+lining. We have now only the handles to put on and it is complete. Sew
+these on with a five cord thread well waxed. To protect the lock
+against being unduly strained when filled, a strap and buckle may be
+put on between the handles and each end of the frame, as in Fig. 3.</p>
+
+<p>Next in order is the cricket bat bag, which should always be comprised
+in the outfit of the amateur cricketer, as well as of the
+professional. In making this we follow the instructions given for the
+carpet bag. It may be made either of carpet, tan-canvas, or leather,
+the latter, of course, being the strongest and most expensive. Carpet
+will not require to be described, but a brief description of
+tan-canvas and leather may be of service to the amateur in assisting
+him to choose something for himself.</p>
+
+<p>Tan-canvas, as used for bags and portmanteaux, is a strong, coarse
+material of a brown color; it wears well, and has one advantage over
+carpet&mdash;it is thoroughly waterproof.</p>
+
+<p>Leather is, of course, superior to carpet or canvas, but there are a
+few tricks in its manufacture which it may not be out of place here to
+mention as a caution to the amateur that the old saying, &quot;There's
+nothing <i>like</i> leather,&quot; is a thing of the past where the general
+appearance of an article is meant. The genius of the inventor has
+produced machinery which gives to paper, linen, and other stuffs the
+appearance of the genuine article, whereas it does not contain one
+particle of it. At one time, when a hide of leather was required to be
+of the same thickness all over it, the currier would work at the flesh
+of the skin with a shaving knife, gradually scraping the thick parts
+away until it was reduced to the required substance. Now it is done in
+a few minutes. The hide is passed whole between the rollers of a
+splitting machine against the sharp edge of a knife, which reaches
+from one side of the machine to the other, a distance of 10 or 12
+feet. This knife is so gauged that any thickness can be taken off at
+one operation, the part taken off resembling the hide in size and
+shape. The top or grain of the hide is then dressed and finished off
+brown, if for brown hides; or, if to be used for enameled hides, they
+are dyed and japanned. These are called either brown or enameled
+cow-hides, according as they are finished off, and are used for all
+the best class of Gladstone, brief, and other bags. The bottom or
+fleshing of the hide is also dyed and japanned, and when finished,
+exactly resembles in appearance the hide itself, and is very difficult
+for the novice to tell when made up into bags or any other article.
+These are called <i>splits</i>, and having had the best part of the skin
+taken from them, do not wear one-fourth the time the grain will. The
+black enamel soon chips off, which gives them a worn-out appearance.</p>
+
+<p>To make a bag 36 inches by 12 inches by 8 inches requires a frame 36
+inches long, the sides 36½ inches by 14 inches, gussets 14 inches by
+8½ inches, bottom 36½ inches by 8 inches. The lining will be 36 inches
+by 12 inches for the sides, gussets 13 inches by 8 inches, bottom 36
+inches by 8 inches. For the handles two pieces of leather 12 inches by
+2 inches. The straps and chapes are sewn on quite close to the frame,
+straps 10 inches long by 1 inch, chapes 4½ inches by 1 inch. Cut a
+slit in the middle of the chape for the buckle tongue to go through,
+and pare the under side at the end so that it is not too lumpy when
+sewn on to the bag. Cut two loops 3 inches long by ¾ inch wide for the
+points of straps to go through.</p>
+
+<p>The brief bag must be made of leather, and as there is the same amount
+of work in making it, whether it be of split or hide, it will be sure
+to give greater satisfaction if the latter is chosen. The manufacture
+of this bag differs considerably from the others. The sides and
+gussets in the carpet bag are cut straight from top to bottom, but in
+the brief bag they must be shaped to fit the frame, and give it a more
+comely appearance. The frame, as before described, is quite different.
+The way to commence with this bag is to open the frame as in Fig. 7,
+so that it will lie perfectly flat upon the bench. With the rule
+measure it carefully between the corners, A, A, and again at A, B. The
+distance between A and B being less when the frame is open than when
+closed, an additional ½ inch must be added to allow the gusset to bend
+freely round the hinge. Having correctly taken these measurements, get
+a sheet of brown paper and fold it in the middle; the reason for this
+is to allow of each side of the pattern taking the same curve at the
+swelled part. Cut the pattern for the sides first by ascertaining half
+the distance, A, A, and marking it on to the edge of the paper,
+measuring from the folded edge toward the ends. Next mark on the
+folded edge the depth you intend the bag to be, allowing in this, as
+in the carpet bag, 1½ inches for covering the frame. The depths of
+brief bags vary so much that I will give these only as a guide,
+leaving my readers to add or reduce as their fancy guides them; but if
+they should strictly adhere to these given below, I am certain they
+will find them very useful sizes.</p>
+
+<p>For a 12 inch frame cut the sides and gussets 10½ inches in depth;
+when made up, these will be 9 inches from the frame to the bottom. For
+a 14 inch frame add 1 inch, and for a 16 inch add 2 inches. This will
+make these 10 inches and 11 inches in depth respectively when made up,
+and either of these will be found a very useful bag for many purposes.
+The width of the bottoms to be cut 5 inches, 5½ inches, and 6 inches,
+the 5 inch, of course, for the 12 inch bag, the 5½ inch for the 14
+inch, and the 6 inch for the 16 inch. The depth having been decided
+upon, and marked on the folded edge of the paper, make another mark
+the same distance from the edge at the first mark, H. The bottom of
+the sides being 1 inch longer than the top, add ½ inch to the
+measurement of the top of pattern when the bottom part is marked off
+at J L. Draw a curved line between H L, as in Fig. 9, and cut through
+the two thicknesses of paper at one time, keeping them well together
+to insure them being alike. The gusset pattern may be cut in the same
+way, D to D, Fig. 10, being half the distance of A B, Fig. 7, and the
+½ inch added for going round the joint; E E, the swelled part, which
+bends into the bag when the frame is closed, and also allows it to
+open perfectly square; F F is half the width of the bottom of gusset.
+A pattern for the bottom of the bag may be made by folding a piece of
+paper each way to get the length and width; make a small hole through
+the four thicknesses, open it and mark it from hole to hole, using the
+rule as a guide. This will be found to be perfectly accurate.</p>
+
+<p>To cut out the bag, lay the leather on the bench, enameled side
+downward, and see that the patterns lie on it so the creases will run
+from the top to bottom of the bag when made. The sides must be taken
+first, and as they are more exposed than any other part, they should
+be taken from the best part of the hide. Take the gussets next, then
+the bottom. The welts are taken from the cuttings which are left. To
+make the handle, glue a lot of odd pieces together about 6½ inches
+long, ½ inch wide, and the same thickness, and when dry pare the edges
+away until it is perfectly round and slightly tapering toward each
+end. It is then divided and glued top and bottom to a strip of good
+leather cut to shape, Fig. 12, which is passed through the rings at
+each end, and turned back to form a shape. Put a few stitches through
+close to the rings before the fittings are glued on, and cover with a
+piece of cow-hide long enough to go through the two rings and along
+the under side, then stitch it. Trim and dye the edges, rubbing them
+afterward with a piece of cloth to produce a polish. Before making the
+handle, the plates must be on the rings, or it will prove a difficult
+job to get them on afterward.</p>
+
+<p>The stiffening for the bottom will be cut as if for a carpet bag. Fig.
+11 represents the stiffening for the gussets, and is cut from a board
+half the thickness of that used for the bottom.</p>
+
+<p>The linings may be cut from the outside patterns by reducing them the
+1½ inches, allowed for covering the frame, and 1/8 inch for each welt.
+A lining of scarlet or blue roan greatly adds to the appearance and
+durability of a bag. A skin large enough for a 14 inch or 16 inch will
+cost about 3s.</p>
+
+<p>Cow-hide for the outside is sold at 1s. 8d. per square foot, but the
+leather sellers frequently have pieces large enough for making a bag
+which they will sell at a slight reduction, and which answers this
+purpose as well as cutting a hide. In seaming the bag, take care not
+to wrinkle it in the clams. The welts in this must reach only to the
+frame, the same as in the carpet bag; the rest of the seam must be
+neatly closed and rubbed down, so that it will not be lumpy on the
+frame. Before turning the bag warm it before the fire, especially if
+it is cold weather. Glue in the bottom stiffening first, and then the
+gussets, rubbing them well down with the bone. When these are set,
+prepare for the operation of framing. Fold one of the sides to get the
+middle of it, cut a hole for the lock barrel about 1¼ inches from the
+edge, and press it over. Be careful not to cut it too large or the
+hole will show. Pierce a hole through the leather for the lock plate,
+press this tightly on the frame, and clinch the clams underneath, to
+hold it securely. Make holes for the handle plates and fasten them on
+in a similar manner. Two slits must be cut near the middle of the
+other side of bag, about ¾ inch from the edge, for the hasp to go
+through. This bag must be sewn to the frame all round, and care must
+be taken that a sufficient fullness is allowed in the middle of the
+gusset to enable it to close easily round the joints of the frame. A
+thumbpiece must be sewn on the bag at the hasp to open it by. The
+lining of this bag is sewn through the frame all round in the same
+manner as the side linings of the carpet bag.</p>
+
+<p>I hope my readers will not think that I have gone too much into
+details. It is in small things that so many failures take place. As it
+is much easier to do anything when you are shown than when so much has
+to be guessed, it is my desire to make the road for beginners as
+smooth as possible, which must be my excuse if any is required. It is
+as well that those who intend to turn their attention to working in
+leather should begin by making a bag; the experience gained in
+cutting, fitting, putting together, and finishing will be useful when
+larger and more difficult pieces of work are undertaken.&mdash;<i>Amateur
+Mechanics.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art22" id="art22"></a>MOLASSES, HOW MADE.</h2>
+
+
+<p>The <i>New England Grocer</i> says that the manufacture of molasses is
+really the manufacture of sugar up to a certain stage, for molasses is
+the uncrystallized sirup produced in the making of sugar. The methods
+of manufacture in the West Indies vary very considerably. In the
+interior and on the smaller plantations it is made by a very primitive
+process, while on the larger plantations all the appliances of modern
+science and ingenuity are brought to bear. Each planter makes his own
+sugar. It is then carried to the sea coast and sold to the exporters,
+by whom it is shipped to this country. The quality and grade of the
+molasses varies with each plantation. Two plantations side by side may
+produce entirely different grades. This is owing to the soil, which in
+Porto Rico and other localities in the West Indies seems to change
+with almost every acre. The cane from which the sugar and molasses is
+made is planted by laying several pieces of it in holes or trenches.
+The pieces are then covered with earth to the depth of two or three
+inches. In about two weeks sprouts appear above the surface. Then more
+earth is put in, and as the sprouts grow, earth is added until in
+three or four months the holes are filled up. The planting is done
+from August to November, and the cutting progresses throughout the
+greater part of the year. The cane grows to a height of seven or eight
+feet, in joints each about a foot long.</p>
+
+<p>When the cane is in proper condition for cutting, as shown by its
+appearance, an army of workmen take possession of the field. Each is
+armed with a long, broad knife, like a butcher's cleaver. They move
+down the lines of cane like an army, and while the cutting is going on
+the fields present an interesting sight, the sword-like knives
+flashing in the sun, the 300 or 400 laborers, the carpet of cut cane,
+the long line of moving carts, and the sea of standing cane, sometimes
+extending for miles and miles, stirred by the breeze into waves of
+undulating green. The laborers employed on these plantations are
+largely negroes and Chinese coolies. When the cane is ripe, they
+proceed to the field, each armed with a <i>matchet</i>. Spreading over the
+plantation, they commence the cutting of the cane, first by one cut at
+the top, which takes off the long leaves and that part which is
+worthless, except as fodder for the cattle. A second cut is then given
+as near the root as possible, as the nearer the ground the richer the
+cane is in juice. The cut cane is allowed to fall carelessly to the
+ground.</p>
+
+<p>Other workmen come with carts, pick it up, tie it in <a
+name="Page_8962" id="Page_8962"></a>bundles and carry it to the mill. The cutting of
+the cane is so adjusted as to keep pace with the action of the mill,
+so that both are always at work. Two gangs of men are frequently
+employed, and work goes on far into the night during the season, which
+lasts the greater part of the year.</p>
+
+<p>As before stated, some of the methods of manufacture are very simple.
+In the simplest form, the sugar cane is crushed in a mortar. The juice
+thus extracted is boiled in common open pans. After boiling a certain
+length of time, it becomes a dark colored, soft, viscid mass. The
+uncrystallized sirup is expressed by putting the whole into cloth bags
+and subjecting them to pressure. This is molasses in a crude state. It
+is further purified by reboiling it with an addition of an alkaline
+solution and a quantity of milk. When this has continued until scum no
+longer arises, it is evaporated and then transferred to earthen jars.
+After it has been left for a few days to granulate, holes in the
+bottom of the jars are unstopped, and the molasses drains off into
+vessels placed to receive it. Another process of extracting molasses
+is as follows: By various processes of boiling and straining, the
+juice is brought to a state where it is a soft mass of crystals,
+embedded in a thick, but uncrystallized, fluid. The separation of this
+fluid is the next process, and is perfected in the curing house, so
+called. This is a large building, with a cellar which forms the
+molasses reservoir. Over this reservoir is an open framework of
+joists, upon which stands a number of empty potting casks. Each of
+these has eight or ten holes bored through the bottom, and in each
+hole is placed the stalk of a plantain leaf. The soft, concrete mass
+of sugar is removed from the cooling pans in which it has been brought
+from the boilers and placed in the casks. The molasses then gradually
+drains from the crystallized portion into the reservoir below,
+percolating through the spongy plantain stalks.</p>
+
+<p>On the larger plantations, machinery of very elaborate description is
+used, and the most advanced processes known to science are employed in
+the manufacture. The principle is, however, the same as has been seen
+in the account of the simpler processes. On these larger plantations
+there are extensive buildings, quarters for workmen, steam engines,
+and all the necessary adjuncts of advanced manufacturing science. In
+the sugar mills the cut cane is carried in carts to the mill. It is
+then thrown by hand upon an endless flexible conductor which carries
+the cane between heavy crushers. The great jaws of the crushers press
+the cane into pulp, when it is thrown aside automatically to be carted
+away and used as a fertilizer. The juice runs off in the channels of
+the conductor into huge pans. The juice is now of a dull gray color
+and of a sweet, pleasant taste, and is known as <i>guarapo</i>. It must be
+clarified at once, for it is of so fermentable a nature that in the
+climate of Porto Rico it will run into fermentation inside of half an
+hour if the process of clarifying is not commenced. The pans into
+which the juice is conducted are pierced like a colander. The liquor
+runs through, leaving the refuse matter behind. It is then forced into
+tanks by a pump and run to the clarifiers, which are large kettles
+heated by steam. Lime is used to assist the clarification. It is then
+filtered into vats filled with bone black. The filtering is repeated
+until the juice changes color, when it is conveyed to the vacuum pans.
+It has now become a thick sirup. It is then pumped into the sirup
+clarifiers, skimmed, and again run through bone black, and finally is
+conducted into another kettle, where it is allowed to crystallize. The
+sirup that fails to crystallize is molasses, and it is here that we
+catch up with what we started after. To extract the molasses from the
+crystallized mass of sugar, we must go to the purging house. This is
+similar to the building spoken of in connection with the simpler
+process. It is of two stories. The upper floor is merely a series of
+strong frames with apertures for funnel-shaped cylinders. The sugar is
+brought into the purging house in great pans, which are placed over
+the funnels. The pans are pierced with holes through which the
+molasses drains off into troughs which are underneath the floor, all
+running to a main trough. From thence the molasses runs into vats,
+called <i>bocoyes</i>, each of which holds from 1,200 to 1,500 gallons. The
+hogsheads in which the molasses is brought to this country are
+manufactured principally in Philadelphia and taken to the West Indies.
+They are placed in the hold of the vessel and the molasses pumped into
+them. The government standard for molasses is 56 degrees polarization.
+When not above that test, the duty is four cents per gallon. Above it
+the duty is eight cents. This tends to keep molasses pure, as the
+addition of glucose increases the quantity of sugar and therefore of
+the polarization, and would make necessary the payment of increased
+duties. The adulteration of molasses is therefore largely if not
+wholly done after it is out of bond and in the hands of the jobber.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art11" id="art11"></a>PRIMITIVE IRON MANUFACTURE.</h2>
+
+
+<p>We are indebted for the illustrations and the particulars to Dr.
+Percy's invaluable book on iron and steel (probably it is not saying
+too much to describe it as the best work on the subject ever written).</p>
+
+<p class="center"><img src="./images/12a.png" alt="SECTION OF INDIAN BLAST FURNACE AND BLOWING" />
+<br /> SECTION OF INDIAN BLAST FURNACE AND BLOWING
+MACHINE.</p>
+
+<p>Fig. 1 shows a sectional elevation, and Fig. 2 shows a plan of furnace
+and bellows and tuyeres, indeed, an entire ironworks plant used in
+India, not only now, but, so far as we can gather, from time
+immemorial. The two figures give a sufficiently clear idea of the form
+of furnace used in Lower Bengal, in which portion of our Indian empire
+there are entire villages exclusively inhabited by iron smelters, who,
+sad to relate, are distinguished from the agricultural villages
+surrounding them by their filth, poverty, and generally degraded
+condition. There are whole tribes in India who have no other
+occupation than iron smelting. They, of course, sink no shafts and
+open no mines, and are not permanent in any place. They simply remain
+in one place so long as plentiful supplies of ore and wood are
+obtainable in the immediate vicinity. In many cases the villages
+formerly inhabited by them have passed out of existence, but the
+waste, or rather wasted products, of their operations remain.</p>
+
+<p>The furnace shown in Figs. 1 and 2 is built of the sandy soil of the
+district, moistened and kneaded and generally strengthened by a sort
+of skeleton of strips of flexible wood. In form it varies from a
+cylinder, more or less circular, diverging into a tolerably acute
+cone, the walls being about 3 in. thick. The height is generally about
+3 ft. and the mean internal diameter about 1 ft., but all these
+dimensions vary with different workmen and in different localities.
+There are two apertures at the base of the furnace; one in front,
+about 1 ft. in height, and rather less in width than the internal
+diameter of the furnace, through which, when the smelting of one
+charge is finished, the resulting mass of spongy iron is extracted,
+and which during the smelting is well plastered up, the small conical
+tuyere being inserted at the bottom. This tuyere is usually made of
+the same material as the furnace&mdash;namely, of a sandy soil; worked by
+hand into the required form and sun-dried; but sometimes no other
+tuyere is employed than a lump of moist clay with a hole in it, into
+which the bamboo pipes communicating with the bellows are inserted.
+The other aperture is smaller, and placed at one side of the furnace,
+and chiefly below the ground, forming a communication between the
+bottom of the furnace chamber and a small trench into which the slag
+flows and filters out through a small pile of charcoal. It is this
+slag being found in places where iron is not now made that shows that
+iron smelting was an occupation there, perhaps many centuries before.</p>
+
+<p>The inclined tray shown at the top of the furnace on Fig. 1 is made of
+the same material as the furnace itself, and when kneaded into shape
+is supported on a wooden framework. On it is piled a supply of
+charcoal, which is raked into the furnace when required.</p>
+
+<p>The blowing apparatus is singularly ingenious, and is certainly as
+economical of manual labor as a blowing arrangement depending on
+manual labor well can be. A section of the bellows forms the portion
+to the right of Fig. 1, showing tuyere forming the connection between
+bellows and furnace. It consists of a circular segment of hard wood,
+rudely hollowed, and having a piece of buffalo hide with a small hole
+in its center tied over the top. Into this hole a strong cord is
+passed, with a small piece of wood attached to the end to keep it
+inside the bellows, while the other end is attached to a bent bamboo
+firmly fixed into the ground close by. This bamboo acts as a spring,
+drawing up the string, and consequently the leather cover of the
+bellows, to its utmost stretch, while air enters through the central
+hole. When thus filled, a man places his foot on the hide, closing the
+central hole with his heel, and then throwing the whole weight of his
+body on to that foot, he depresses the hide, and drives the air out
+through a bamboo tube inserted in the side and communicating with the
+furnace. At the same time he pulls down the bamboo with the arm of
+that side. Two such bellows are placed side by side, a thin bamboo
+tube attached to each, and both entering the one tuyere; and so by
+jumping on each bellows alternately, the workman keeps up a continuous
+blast.</p>
+
+<p class="center"><img src="./images/12b.png" alt="Fig. 2.&mdash;PLAN OF INDIAN BLAST FURNACE AND BLOWING" />
+<br /> Fig. 2.&mdash;PLAN OF INDIAN BLAST FURNACE AND BLOWING MACHINE.</p>
+
+<p>The Figs. 1 and 2 are taken from sketches, and the description from
+particulars, by Mr. Blandford, who was for some years on the
+Geological Survey of India, and had exceptional opportunities in his
+journeyings of observing the customs and occupations of the Indian
+iron smelters. The blowing machine is an especially wonderful and
+effective machine, and was first described and illustrated by Mr.
+Robert Rose, in a Calcutta publication, more than half a century ago.
+He also had seen it used in iron making in India.&mdash;<i>Colliery
+Guardian.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art27" id="art27"></a>WOOD OIL.</h2>
+
+
+<p>Wood oil is now made on a large scale in Sweden from the refuse of
+timber cuttings and forest clearings, and from stumps and roots.
+Although it cannot well be burned in common lamps, on account of the
+heavy proportion of carbon it contains, it is said to furnish a
+satisfactory light in lamps specially made for it; and in its natural
+state it is the cheapest illuminating oil. There are some thirty
+factories engaged in its production, and they turn out about 40,000
+liters of the oil daily. Turpentine, creosote, acetic acid, charcoal,
+coal-tar oils, etc., are also obtained from the same materials as the
+wood oil.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art24" id="art24"></a>SOAP.</h2>
+
+<h3>By HENRY LEFFMANN, M.D.</h3>
+
+
+<p>Although the use of soap dates from a rather remote period, the
+chemist is still living, at an advanced age, to whom we are indebted
+for a knowledge of its composition and mode of formation.
+Considerably more than a generation has elapsed since Chevreul
+announced these facts, but a full appreciation of the principles
+involved is scarcely realized outside of the circle of professional
+chemists. Learned medical and physiological writers often speak of
+glycerin as the &quot;sweet principle of fats,&quot; or term fats compounds of
+fatty acids and glycerin. Indeed, there is little doubt that the great
+popularity of glycerin as an emollient arose from the view that it
+represented the essential base of the fats. With regard to soap, also,
+much erroneous and indistinct impression prevails. Its detergent
+action is sometimes supposed to be due to the free alkali, whereas a
+well-made soap is practically neutral.</p>
+
+<p>A desire to secure either an increased detergent, cleansing, or other
+local effect has led in recent years to the introduction into soaps of
+a large number of substances, some of which have been chosen without
+much regard to their chemical relations to the soap itself. The result
+has been the enrichment of the materia medica with a collection of
+articles of which some are useful, and others worse than useless. The
+extension of the list of disinfectant and antiseptic agents and the
+increased importance of the agents, in surgery, have naturally
+suggested the plan of incorporating them with soaps, in which form
+they will be most convenient for application. Accordingly, the
+circulars of the manufacturing pharmacists have prominently displayed
+the advantages of various disinfecting soaps.</p>
+
+<p>Among these is a so-called corrosive sublimate soap, of which several
+brands are on sale. One of these, containing one per cent. of
+corrosive sublimate, is put on the market in cakes weighing about
+sixteen hundred grains, and each cake, therefore, contains sixteen
+grains of the drug&mdash;a rather large quantity, perhaps, when it is
+remembered that four grains is a fatal dose. Fortunately, however, for
+the prevention of accidents, but unfortunately for the therapeutic
+value of the soap, a decomposition of the sublimate occurs as soon as
+it is incorporated in the soap mass, by which an insoluble mercurial
+soap is formed. This change takes place independently of the alkali
+used in the soap; in fact, as mentioned above, a well-made soap
+contains no appreciable amount of free alkali, but is due to the
+action of the fat acids. Corrosive sublimate is <i>incompatible</i> with
+any ordinary soap mass, and this incompatibility includes not only
+other soluble mercurial salts, but also almost all the mineral
+antiseptics, such as zinc chloride, copper sulphate, iron salts. Some
+of the preparations of arsenic may, however, be incorporated with soap
+without decomposition.</p>
+
+<p>Such being the chemical facts, we must admit that no reliance can be
+placed in corrosive sublimate soaps as germicide agents. It must not
+be supposed that this incompatibility interferes with the use of these
+soaps for general therapeutic purposes. It is only the specific
+germicide value which is destroyed. Since the fats used in soap
+manufacture yield oleic acid, we will have a certain amount of
+mercuric oleates formed together with stearate and other salts, and
+for purposes of inunction these salts might be efficient. Still the
+physician would prefer, doubtless, to use the specially prepared
+mercurial.</p>
+
+<p>In producing, therefore, a disinfecting soap, being debarred from
+using the metallic germicides, we are fortunate in the possession of a
+number of efficient agents, organic in character, which may be used
+without interference in soaps.</p>
+
+<p>Among these are thymol, naphthol, oil of eucalyptus, carbolates, and
+salicylates. There is no chemical incompatibility of these with soap,
+and as they are somewhat less active, weight for weight, than
+corrosive sublimate, they are capable of use in larger quantities with
+less danger, and can thus be made equally efficacious.</p>
+
+<p>It is in this direction, therefore, that we must look for the
+production of a safe and reliable antiseptic soap.</p>
+
+<p>There is not much exact knowledge as to the usefulness of such
+additions to soap as borax and glycerin. They are frequently added,
+and highly spoken of in advertisements. Borax is a mild alkaline body,
+and as a detergent is probably equivalent to a slight excess of
+caustic soda. Glycerin, although originally considered an emollient,
+probably on account of its source and physical properties, is in
+reality, to some skins at least, a slight irritant. It is, in fact, an
+alcohol, not a fat. It does not pre-exist in fats, but is formed when
+the fat is decomposed by alkali or steam.</p>
+
+<p>In ordinary cases, soap owes its detergent effect to a decomposition
+which occurs when it is put in water.</p>
+
+<p>A perfectly neutral soap, that is, one which contains the exact
+proportion of alkali and fat acid, will, when placed in cold water,
+decompose into two portions, one containing an excess of the acid, the
+other an excess of alkali. The latter dissolves, and gives a slightly
+alkaline solution; the former precipitates, and gives the peculiar
+turbidity constituting &quot;suds.&quot; These reactions must be kept in mind in
+determining the effect of the addition of any special substance to the
+soap.&mdash;<i>The Polyclinic.</i></p>
+
+<hr />
+
+
+
+
+
+<h2><a name="art23" id="art23"></a><a name="Page_8963" id="Page_8963"></a>OPTICAL ERRORS AND HUMAN MISTAKES.<a name="FNanchor_8" id="FNanchor_8"></a><a href="#Footnote_8"><sup>1</sup></a></h2>
+
+<h3>By ERNST GUNDLACH.</h3>
+
+
+<p>I wish to call attention to a few mistakes that are quite commonly
+made by microscopists and writers in stating the result of their
+optical tests of microscope objectives.</p>
+
+<p>If the image of an object as seen in the microscope appears to be
+unusually distorted and indistinct toward the edge of the field, and
+satisfactory definition is limited to a small portion of the center,
+the cause is often attributed to the spherical aberration of the
+objective, while really this phenomenon has nothing to do with that
+optical defect of the objective, if any exists, but is caused by a
+lack of optical symmetry. If a perfectly symmetrical microscope
+objective could be constructed, then, with any good eye-piece, it
+would make no difference to the definition of the object were it
+placed either in the center or at the edge of the field, even if the
+objective had considerable spherical aberration. But, unfortunately,
+our most symmetrical objectives, the low powers, leave much to be
+desired in this respect, while our wide angle, high powers are very
+far from symmetrical perfection.</p>
+
+<p>There are two causes of this defect in the latter objectives, one
+being the extreme wideness of their angular apertures, and the other
+the great difference in the distances of the object and the image from
+the optical center of the objectives.</p>
+
+<p>Another mistake is often made in regard to the cause of certain
+prismatic colors that are sometimes, in a striking degree, produced by
+otherwise good objectives. According to the nature of these colors,
+whether yellow or blue, green or indigo, they are generally regarded
+as evidences of either chromatic over or under correction of the
+objective. Of course the presence of either of these defects is
+certainly and correctly indicated by the appearance of one or the
+other of the colors, under certain circumstances; but the simple
+visibility of prismatic color is by no means a reliable indication of
+over or under correction of color, and, indeed, to the honor of our
+opticians, it may be stated that very few objectives are made that
+cannot justly be called achromatic in the general sense of the term.
+By far the most common causes of prismatic color, in otherwise
+carefully constructed objectives, are the so-called chromatic
+aberrations of second or higher order. Every achromatic lens which is,
+as it should be, at its best at about two-thirds of its aperture, is
+inside of this ring or zone, toward the center slightly under and
+outside, toward the edge, slightly over corrected. This defect is the
+greater, the less the difference of the dispersive powers of the two
+glasses used in the construction of the lens, for a given proportion
+of their refractive indexes, and therefore the degree of visibility of
+the colors of the aberrations of the second order depends greatly on
+the nature of the glass employed in the construction of the lens.</p>
+
+<p>This defect may be corrected by a suitable combination of two or more
+lenses, though not without again having similarly, as in the
+correction of the first color, some faint remnants of color, the
+aberrations of third or still higher order. But even the correction of
+the third or still higher order may, if the angular aperture is very
+wide, leave quite visible and disturbing remnants of color.</p>
+
+<p>Another and not uncommon explanation of the cause of this unwelcome
+color, though not so serious and damaging a charge to the maker of the
+objectives, is its attribution to the so-called &quot;secondary spectrum.&quot;
+This error, like that previously mentioned, is certainly indicated by
+the appearance of certain colors under certain conditions, but being,
+as a rule, one of the least defects of even our best objectives in
+most cases, it is probably not the true source of the disturbance.</p>
+
+<p>The secondary spectrum is very commonly confounded with the chromatic
+aberration of higher order. While the latter is produced by
+imperfections in the form of the lens, the former is due to an
+imperfection of the optical qualities of the material from which the
+lens is constructed, the crown and flint glass.</p>
+
+<p>A glass prism of any angle will project upon a white surface a
+spectrum of any length, according to the arrangement of the light
+source, the screen, and the prism. So with two prisms of the same kind
+of glass, but of different angles, two spectra can be produced of
+exactly equal length, so that if one is brought over the other, with
+the corresponding colors in line, they will appear as one spectrum.
+But if one of the prisms is made of crown and the other of flint
+glass, then their spectra cannot be arranged so that all their
+corresponding colors would be in line, for the proportional distances
+of the different colors differ in the two spectra. If two colors of
+the spectra are, by suitable arrangement, brought exactly in line,
+then the others will be out. The two spectra do not coincide, and the
+result, if an achromatic lens be made of these glasses, must be a
+remnant of color which cannot be neutralized. This remnant is the
+secondary spectrum.</p>
+
+<p>Although this peculiar disharmony in the dispersive powers of the two
+glasses, crown and flint, was discovered almost immediately after
+achromatism was invented, it was only recently that the first
+successful attempts were made to produce different glasses, which,
+possessing the other requirements for achromatic objectives, would
+produce coincident spectra, or nearer so than the ordinary crown and
+flint glass do. It was about twelve years ago, if my memory serves me,
+when I learned that a well-known English firm, engaged in the
+manufacture of optical glass, had brought out some new glass
+possessed of the desired qualities, and a little later I received a
+circular describing the glass. But at the same time I learned that the
+new glass was very soft and difficult to polish, and also that it had
+to be protected from the atmosphere, and further, that an English
+optician had failed to construct an improved telescope objective from
+it. I had ordered some samples of the glass, but never received any.</p>
+
+<p>A few months ago, news from Europe reached this country that another
+and seemingly more successful attempt had been made to produce glass
+that would leave no secondary spectrum, and that Dr. Zeiss, the famous
+Jena optician, had constructed some new improved objectives from it.
+But the somewhat meager description of these objectives, as given by
+an English microscopist, did not seem fit to excite much enthusiasm
+here as to their superiority over what had already been done in this
+country. Besides this, the report said that the new objectives were
+five system, and also that extra eye-pieces had to be used with them.
+I confess I am much inclined to attribute the optical improvement,
+which, according to Dr. Abbe's own remark, is very little, more to the
+fact that the objectives are five system than to the new glass used in
+their construction.</p>
+
+<p>After a close study of a descriptive list of the new glass, received a
+week or two ago from the manufacturers, I find, to my great regret,
+that this new glass seems to suffer from a similar weakness to that
+made by the English firm twelve years ago; as all the numbers of the
+list pointed out by the makers as having a greatly reduced secondary
+spectrum are accompanied with the special remark &quot;to be protected.&quot;
+Furthermore, from a comparison of the dispersive and refractive powers
+of these glasses, as given in the list, I find that objectives
+constructed from them will leave so great aberrations of higher order,
+both spherical and chromatic, that the gain by the reduction of the
+secondary spectrum would be greatly overbalanced.</p>
+
+<p>In conclusion, I wish to say that while I would beware of
+underestimating the great scientific and practical value of the
+endeavor of the new German glass makers to produce improved optical
+glass, and the great benefit accruing to opticians and all others
+interested in the use of optical instruments, I think it wise not to
+overestimate the real value of the defects of the common crown and
+flint glass, which I have sought to explain in this paper. And, for
+myself, I prefer to fight the more serious defects first, and when its
+time has come I will see what can be done with the secondary spectrum.</p>
+
+<p><a name="Footnote_8" id="Footnote_8"></a><a href="#FNanchor_8">[1]</a></p><div class="note">
+<p>Read before the American Association, Buffalo, August,
+1886.</p></div>
+<hr />
+
+
+
+<h2><a name="art03" id="art03"></a>PROBABLE ISOLATION OF FLUORINE. DECOMPOSITION OF HYDROFLUORIC ACID
+BY AN ELECTRIC CURRENT.</h2>
+
+<h3>By M.H. MOISSAN.</h3>
+
+
+<p>In a former memoir<a name="FNanchor_9" id="FNanchor_9"></a><a href="#Footnote_9"><sup>1</sup></a> we showed that it was possible to decompose
+anhydrous hydrofluoric acid by the action of an electric current. At
+the negative pole hydrogen collects; at the positive pole a gaseous
+body is disengaged, having novel properties. The experiment was
+performed in a platinum U tube, closed by stoppers of fluorite, and
+having at the upper part of each branch a small delivery tube, also of
+platinum. Through the stopper passes a platinum rod, which acts as
+electrode. The metal employed for the positive pole is an alloy
+containing 10 per cent. of iridium.</p>
+
+<p>To obtain pure anhydrous hydrofluoric acid, we begin by preparing
+fluorhydrate of fluoride of potassium, taking all the precautions
+pointed out by M. Fremy. When the salt is obtained pure, it is dried
+on a water bath at 100°, and the platinum capsule containing it is
+then placed in a vacuum in the presence of concentrated sulphuric
+acid, and two or three sticks of potash fused in a silver crucible.
+The acid and potash are renewed every morning for a fortnight, and the
+vacuum is kept at 2 cm. of mercury. Care must be taken during this
+desiccation to pulverize the salt every day in an iron mortar, so as
+to renew the surface. When the fluorhydrate contains no more water it
+falls to powder, and is then fit to serve for the preparation of
+fluoric acid; the fluorhydrate of fluoride of potassium, if well
+prepared, is much less deliquescent than the fluoride.</p>
+
+<p>When the fluoride is quite dry, it is quickly introduced into a
+platinum alembic, which has just been dried by heating it to redness.
+The whole is kept at a gentle temperature for an hour or an hour and a
+half, so as to allow the decomposition to commence very slowly; the
+first portions of acid which come over are rejected as they carry with
+them traces of water remaining in the salt. The platinum receiver is
+then attached, and the heat increased, allowing the decomposition to
+proceed with a certain degree of slowness. The receiver is then
+surrounded with a mixture of ice and salt, and from this moment all
+the hydrofluoric acid is condensed as a limpid liquid, boiling at
+19.5°, very hygroscopic, and, as is well known, giving abundant fumes
+in presence of the atmospheric moisture.</p>
+
+<p>During this operation the platinum U tube, dried with the greatest
+care, has been fixed with a cork in a cylindrical glass vessel
+surrounded with chloride of methyl. Up to the moment of introducing
+the hydrofluoric acid, the leading tubes are attached to drying tubes
+containing fused caustic potash. To introduce the hydrochloric acid
+into the apparatus, it may be absorbed through one of the lateral
+tubes in the receiver in which it is condensed.</p>
+
+<p>In some experiments we have directly condensed the hydrofluoric acid
+in the U tube surrounded with chloride of methyl; but in this case
+care must be taken that the tubes are not clogged up by small
+quantities of fluoride carried over, which would infallibly lead to an
+explosion and projections, which are always dangerous with so
+corrosive a liquid.</p>
+
+<p>When we have introduced in advance in the small platinum apparatus a
+determined amount of hydrofluoric acid cooled with chloride of methyl,
+in tranquil ebullition at a temperature of -23°, the current of 20
+cells of Bunsen large size, arranged in series, is passed through by
+means of the electrodes. An amperemeter in the circuit admits of the
+intensity of the current being observed.</p>
+
+<p>If the hydrofluoric acid contains a small quantity of water, either by
+accident or design, there is always disengaged at the positive pole
+ozone, which has no action on crystallized silicium. In proportion as
+the water contained in the acid is thus decomposed, it is seen by the
+amperemeter that the conductivity of the liquid rapidly decreases.
+With absolutely anhydrous hydrofluoric acid the current will no longer
+pass. In many of our experiments we have succeeded in obtaining an
+acid so anhydrous that a current of 25 amperes was entirely arrested.</p>
+
+<p>To render the liquid conducting, we have added before each experiment
+a small quantity of dried and fused fluorhydrate of fluoride of
+potassium. In this case, decomposition proceeds in a continuous
+manner; we obtain at the negative pole hydrogen, and at the positive
+pole a regular disengagement of a colorless gas in which crystallized
+silicium in the cold burns with great brilliancy, becoming fluoride of
+silicium. This latter gas has been collected over mercury, and
+accurately characterized.</p>
+
+<p>Deville's adamantine boron burns in the same manner, but with more
+difficulty, becoming fluoride or boron. The small quantity of carbon
+and aluminum which it contains impedes the combination. Arsenic and
+antimony in powder combine with this gaseous body with incandescence.
+Sulphur takes fire in it, and iodine combines with a pale flame,
+losing its color. We have already remarked that it decomposes cold
+water, producing ozone and hydrofluoric acid.</p>
+
+<p>The metals are attacked with much less energy. This is due, we think,
+to the small quantity of metallic fluoride formed preventing the
+action being very deep. Iron and manganese in powder, slightly heated,
+burn with sparks. Organic bodies are violently attacked. A piece of
+cork placed near the end of the platinum tube, where the gas is
+evolved, immediately carbonizes and inflames. Alcohol, ether, benzol,
+spirit of turpentine, and petroleum take fire on contact.</p>
+
+<p>The gas evolved at the negative pole is hydrogen, burning with a pale
+flame, and producing none of these reactions.</p>
+
+<p>When the experiment has lasted several hours, and there is not enough
+hydrofluoric acid left at the bottom of the tube to separate the two
+gases, they recombine in the apparatus in the cold, with violent
+detonation.</p>
+
+<p>We have satisfied ourselves, by direct experiment, that a mixture of
+ozone and hydrofluoric acid produces none of the reactions described
+above.</p>
+
+<p>It is the same with gaseous hydrofluoric acid. Finally we may add that
+the hydrofluoric acid employed, as well as the hydrofluorate of
+fluoride, were absolutely free from chlorine.</p>
+
+<p>The gas obtained in our experiments is therefore either fluorine or a
+perfluoride of hydrogen.</p>
+
+<p>New experiments are necessary to settle this last point. We hope soon
+to lay the results before the Academy.&mdash;<i>Comptes Mendus</i>, vol. ciii.,
+p. 202, July 19, 1886; <i>Chem. News.</i></p>
+
+
+<p><a name="Footnote_9" id="Footnote_9"></a><a href="#FNanchor_9">[1]</a></p>
+<div class="note"><p><i>Comptes Rendus</i>, vol. cii., p. 1543, and <i>Chemical
+News</i>, vol. liv., p. 36.</p></div>
+
+<hr />
+
+
+
+
+
+<h2><a name="art19" id="art19"></a>COHESION AND COHESION FIGURES.<a name="FNanchor_10" id="FNanchor_10"></a><a href="#Footnote_10"><sup>1</sup></a></h2>
+
+<h3>By WILLIAM ACKROYD, F.I.C.</h3>
+
+
+<h3><i>1. A Law of Solubility.</i></h3>
+
+<p>It is customary to regard cohesion as the force which binds together
+molecules of the same substance, and in virtue of which the particles
+of solids and liquids are kept together, and also to speak of the
+attraction exerted between particles of two different bodies as
+adhesion. The distinction between cohesion and adhesion is a
+conventional one. The similarity, if not identity, of the two forces
+is demonstrated by the fact that while cohesion is exerted between
+particles of the <i>same</i> body, adhesion is exerted with most force
+between particles of <i>allied</i> bodies. Generally speaking, organic
+bodies require organic solvents; inorganic bodies, inorganic solvents.
+For example, common salt is highly soluble in water, but not in ether,
+and many fats are soluble in ether, but not in water. So many cases
+like these will suggest themselves to the chemist that I am justified
+in making the following generalization: <i>A body will dissolve in a
+solvent to which it is allied more readily than in one to which it in
+highly dissimilar.</i> Exceptions to the law undoubtedly exist, but none
+so striking as the following in support of it, viz., that the metal
+mercury is the only known true solvent for many metals at the normal
+temperature.</p>
+
+<h3><i>2. Its Connection with Mendeleeff's Periodic Law.</i></h3>
+
+<p>From this standpoint the whole subject of solution is deserving of
+fresh attention, as it appears highly probable that, just as Prof.
+Carnelley has shown by the use of my meta-chromatic scale, the colors
+of chemical compounds come under definite laws, which he has
+discovered and formulated in connection with Mendeleeff and Newlaud's
+periodic law,<a name="FNanchor_11" id="FNanchor_11"></a><a href="#Footnote_11"><sup>2</sup></a> so, likewise, may the solubility of an allied group
+of compounds, in regard to any given solvent under constant conditions
+of temperature, conform to similar laws; that, <i>e.g.</i>, the chlorides
+of H, Na, Cu, and Ag, in Mendeleeff's Group I., may vary in their
+solubility in water from an extreme of high solubility in the case of
+hydrogen chloride to the opposite extreme of comparative insolubility
+in the case of silver chloride. In this natural series of compounds,
+hydrogen chloride is the body nearest akin to water, and silver
+chloride the most remote in kinship.</p>
+
+<h3><i>3. A Solidified Vortex Ring.</i></h3>
+
+<p>It is in virtue of cohesion that a freely suspended drop of liquid
+assumes the spherical form. If such a sphere be dropped on to the
+surface of a liquid of higher specific gravity at rest, one obtains
+what is called the cohesion figure of the substance of the drop. A
+drop of oil, <i>e.g.</i>, spreads out on the surface of water until it is a
+circular thin film of concentric rings of different degrees of
+thickness, each displaying the characteristic colors of thin plates.
+The tenuity of the film increases; its cohesion is overcome; lakelets
+are formed, and they merge into each other. The disintegrated portions
+of the film now thicken, the colors vanish, and only islets of oil
+remain. Some liquid drops of the same or higher sp. gr. than water do
+not spread out in this fashion, but descend below the surface of the
+liquid, and, in descending, assume a ring shape, which gradually
+spreads out and breaks up into lesser rings. Such figures have been
+termed submergence cohesion figures; they are vortex rings. I have
+solidified such vortex rings in their first stage of formation. If
+drops of melted sulphur, at a temperature above that of the viscous
+state, be let fall into water, the drops will be solidified in the
+effort to form the ring, and the circular button, thick in the rim and
+thin in the center, may be regarded as a solidified vortex ring of
+plastic sulphur.</p>
+
+<h3>4. <i>That a Submergence Cohesion Figure is a Vortex Ring.</i></h3>
+
+<p>It may be shown that the conditions of the formation of a submergence
+cohesion figure are those which exist in the formation of an aerial
+vortex. Those conditions in their greatest perfection are (1) a
+spherical envelope of a different nature from the medium in which the
+rings are produced; (2) a circular orifice opening into the medium;
+and (3) a percussive impact on the part of the sphere opposite the
+orifice. In the <a name="Page_8964" id="Page_8964"></a>production of vortex rings of
+phosphorus pentoxide in the making of phosphoreted hydrogen, the
+spherical envelope is water, the orifice the portion of the bubble
+which opens into the air immediately it rises to the surface, and the
+impact is furnished by gravity. So, also, in the case of a submergence
+cohesion figure, the spherical envelope is the air surrounding the
+drop, the orifice the portion of it which first comes in contact with
+the liquid at rest; and here again the impact is due to gravity more
+directly than in the former case. These conditions are somewhat
+imperfectly copied in the ordinary vortex box, which is usually
+cubical in form, with a circular orifice in one side, and a covering
+of canvas on the opposite one, which is hit with the fist.</p>
+
+<p><a name="Footnote_10" id="Footnote_10"></a><a href="#FNanchor_10">[1]</a></p>
+<div class="note"><p>Notes from a lecture given to the Halifax Scientific
+Society, July 19, 1886.</p></div>
+
+<p><a name="Footnote_11" id="Footnote_11"></a><a href="#FNanchor_11">[2]</a></p>
+<div class="note"><p><i>Philosophical Magazine</i>, August, 1884.</p></div>
+
+<hr />
+
+<h3>[AMERICAN CHEMICAL JOURNAL.]</h3>
+
+
+
+
+
+
+<h2><a name="art04" id="art04"></a>THE DETERMINATION OF NITRIC ACID BY THE ABSORPTION OF NITRIC OXIDE
+IN A STANDARD SOLUTION OF PERMANGANATE OF POTASSIUM.</h2>
+
+<h3>By H.N. MORSE and A.F. LINN.</h3>
+
+
+<p>The method which we propose consists in the conversion of the nitric
+acid into nitric oxide; the absorption of the latter in a measured,
+but excessive, quantity of a standard solution of permanganate of
+potassium; and the subsequent determination of the excess of the
+permanganate by means of a standard solution of oxalic acid or
+sulphate of manganese.</p>
+
+
+<h3>THE APPARATUS.</h3>
+
+<p>A is an apparatus for the generation of carbon dioxide free from air,
+which will be explained hereafter.</p>
+
+<p>B is a flask, having a capacity of 125 or 150 c.c., in which the
+nitrate is decomposed in the usual manner by means of ferrous chloride
+and hydrochloric acid.</p>
+
+<p>C is a small tube for the condensation of the aqueous hydrochloric
+acid which distills over from B.</p>
+
+<p>D is a Geissler bulb, containing a concentrated solution of potassium
+carbonate, to arrest any acid vapors coming from C.</p>
+
+<p>E, E are two pieces of ordinary combustion tubing, having a length of
+about 650 or 700 mm., in which is placed the permanganate solution
+employed for the absorption of the nitric oxide. Their open ends are
+provided with lips in order to facilitate the pouring of liquids from
+them, care being taken not to so distort the ends that rubber stoppers
+cannot be made to fit them tightly. They are placed in a nearly
+horizontal position in order to diminish the pressure required to
+force the gases through the apparatus and thus lessen the danger of
+leakage through the rubber joints.</p>
+
+<p><i>a</i> is a tube through which the ferrous chloride and hydrochloric acid
+are introduced into B, as in the method of Tiemann-Schulze.</p>
+
+<p><i>b</i> serves for the introduction of carbon dioxide to expel the air
+before the decomposition of the nitrate, and the nitric oxide
+afterward.</p>
+
+<p><i>c</i> is an unbroken tube ending at the lower surface of the stopper in
+B, and at the bottom of C.</p>
+
+<p>The rubber joint, <i>d</i>, is furnished with a Mohr and also a screw pinch
+cock. The joints, <i>e</i> and <i>f</i>, are furnished with Mohr pinch cocks.
+The rubber tubing upon these should be of the best quality, and must
+be carefully tied.</p>
+
+<p class="center"><img src="./images/14.png" alt="DETERMINATION OF NITRIC ACID." />
+<br />DETERMINATION OF NITRIC ACID.</p>
+
+
+<h3>THE SOLUTIONS.</h3>
+
+<p>In consequence of the large volume of the permanganate solution
+required for the complete absorption of the nitric oxide, we have
+found it advantageous to use three solutions instead of two.</p>
+
+<p>1. A solution of permanganate such that one c.c. is equivalent to
+about fifteen milligrammes of nitrate of potassium, according to the
+reaction:</p>
+
+
+<p class="center">KMnO<sub>4</sub> + NO = KNO<sub>3</sub> + MnO<sub>2</sub>.</p>
+
+
+<p>This solution is employed for the absorption of the nitric oxide. Its
+strength need not be exactly known. There is no objection to a more
+concentrated solution, except that which pertains to all strong
+standard solutions, namely, that a small error in measurement would
+then give a larger error in the results. 100 c.c. of this solution are
+required for each determination, and the measurement is always made in
+one and the same 100 c.c. measuring flask, which, if necessary, should
+be labeled to distinguish it from that used for solution No. 2.</p>
+
+<p>2. A solution of oxalic acid which is very slightly stronger than that
+of the permanganate just described&mdash;that is, a solution such that one
+c.c. of it will somewhat more than decompose one c.c. of the
+permanganate, according to the reaction:</p>
+
+<p class="center">
+2KMnO<sub>4</sub> + 3H<sub>2</sub>SO<sub>4</sub> + 5C<sub>2</sub>H<sub>2</sub>O<sub>4</sub>.2H<sub>2</sub>O =<br />
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;K<sub>2</sub>SO<sub>4</sub> + 2MnSO<sub>4</sub> + 18H<sub>2</sub>O + 10CO<sub>2</sub>.</p>
+
+
+<p>The exact strength of this solution need not be known, since we only
+require the difference in value between it and solution No. 1, which
+is determined by means of solution No. 3. 100 c.c. of this solution
+are also required for each determination, and the measurement, as in
+the preceding case, is always made in the same 100 c.c. measuring
+flask.</p>
+
+<p>3. A dilute, carefully standardized solution of permanganate of
+potassium.</p>
+
+<p>The method of using these solutions is as follows: 100 c.c. of No. 1
+and No. 2 are measured off (each solution in its own measuring flask),
+brought together in a covered beaker glass, and acidified with dilute
+sulphuric acid. The excess of oxalic acid is then determined by means
+of solution No. 3.</p>
+
+<p>When it is desired to make a determination of nitric acid, 100 c.c. of
+solution No. 1 are measured off, and as much of it as may be
+convenient is poured into the tubes, E, E, together with about a
+gramme of zinc sulphate for each tube, which substance appears to
+considerably facilitate the absorption of the nitric oxide by the
+permanganate. When the operation is over, the contents of E, E are
+poured into a beaker glass. 100 c.c. of solution No. 2 are then
+measured off, and a portion, together with a little sulphuric acid,
+poured into E, E, to dissolve the oxide of manganese which has
+separated during the absorption of the nitric oxide. The oxide having
+been dissolved, the liquid in E, E, and the rinsings of the tubes,
+also the residues of permanganate and oxalic acid left in the
+measuring flasks, and the rinsings from these, are all brought
+together in the same beaker glass. Finally, the amount of solution No.
+3 required to decompose the excess of oxalic acid is determined. If we
+subtract from the amount thus found the quantity of permanganate
+required to equalize solutions Nos. 1 and 2 (previously ascertained),
+we shall have the amount of permanganate actually reduced by the
+nitric oxide, according to the reaction:</p>
+
+<p class="center">6KMnO<sub>4</sub> + 10NO = 3K<sub>2</sub>O + 6MnO + 5N<sub>2</sub>O<sub>5</sub>;</p>
+
+
+<p>in other words, on the basis that one molecule of potassium
+permanganate will oxidize one and two-thirds molecules of nitric
+oxide:</p>
+
+<p class="center">(KMnO<sub>4</sub> = 1-2/3 NO).</p>
+
+<p>The method of using the apparatus is simple. The nitrate is placed in
+B, and the joints made tight, except that at <i>f</i>, which is left open.
+A current of carbon dioxide is passed through the apparatus until all
+of the air has been displaced. Connection is then made at <i>f</i>, and
+soon afterward the current of carbon dioxide is shut off at <i>d</i>.</p>
+
+<p>The flask, B, is now heated as long as may be necessary in order to
+produce, on cooling, the diminished pressure required for the
+introduction of the ferrous chloride and hydrochloric acid. Before
+removing the flame, the joint at <i>f</i> is closed to prevent the return
+of the permanganate solution.</p>
+
+<p>As soon as the flask, B, has become sufficiently cool, the ferrous
+chloride and hydrochloric acid are introduced through the tube, <i>a</i>
+(which has been full of water from the first), in the same manner and
+quantities as in the well-known Tiemann-Schulze method.</p>
+
+<p>The pinch cock at <i>d</i> is then opened, and the apparatus allowed to
+fill with carbon dioxide. When the pressure has become sufficient to
+force the gas through the solution of permanganate, the pinch cock at
+<i>f</i> is removed. It should be opened only slightly and with great
+caution at first, unless one is certain that the pressure is
+sufficient. If the pressure is insufficient, the fact will be made
+apparent by a rise of the permanganate in the small internal tube.</p>
+
+<p>The flow of carbon dioxide is now reduced to a very slow current, or
+entirely cut off. The contents of B are slowly heated, until the
+decomposition of the nitrate is complete and the greater part of the
+nitric oxide has been expelled, when the apparatus is again closed at
+<i>f</i> and <i>d</i>, and allowed to cool. The tube, <i>a</i>, is then washed out,
+by the introduction through it into B of a few cubic centimeters of
+strong hydrochloric acid.</p>
+
+<p>The process of filling the apparatus with carbon dioxide, and of
+heating the contents of B, is repeated. When it becomes apparent, from
+the light color of the liquid in B, that all of the nitric oxide has
+been expelled from it, the current of carbon dioxide is increased and
+the heating discontinued. Care must be taken, however, not to admit
+too strong a current of carbon dioxide, lest some of the nitric oxide
+should be forced unabsorbed through the permanganate solution. It is
+also necessary, for the same reason, to avoid too rapid heating during
+the decomposition of the nitrate.</p>
+
+<p>When all of the nitric oxide has been forced into the solution of
+permanganate, the determination is made in the manner already
+described.</p>
+
+<p>To test the method, nine determinations were made with quantities of
+pure nitrate of potassium varying from 100 to 200 milligrammes. The
+maximum difference between the volumes of permanganate actually used
+and those calculated was 0.05 c.c., while the main difference was
+0.036 c.c. The measurements of the permanganate were made from a
+burette which had been carefully calibrated. We also made a number of
+determinations, using a solution of manganous sulphate in the place of
+the oxalic acid. The advantage of this method lies in the fact that it
+is not necessary to dissolve the oxide which is precipitated upon the
+glass within the tubes, E, E, since, in the presence of an excess of
+permanganate, the reduction by nitric oxide extends only to the
+formation of MnO<sub>2</sub>; also in the fact that the solution of manganous
+sulphate is more stable than that of oxalic acid. A solution of the
+sulphate having been once carefully standardized, can be used for a
+long time to determine the value of permanganate solutions.</p>
+
+<p>The details of the method are as follows: A solution of manganous
+sulphate slightly stronger than No. 1 is prepared.</p>
+
+<p>The difference between 100 c.c. of it and 100 c.c. of No. 1 is
+ascertained, according to the method of Volhard, by means of solution
+No. 3.</p>
+
+<p>The contents of E, E, together with the rinsings from the tubes, are
+poured into a capacious flask. 100 c.c. of the manganous sulphate and
+a few drops of nitric acid are then added, and the whole boiled.
+Finally, the excess of manganous sulphate is determined, in the manner
+described by Volhard, by means of solution No. 3. Subtracting from the
+total amount of permanganate thus used the quantity required to
+equalize the 100 c.c. of solution No. 1 and the 100 c.c. of the
+manganous sulphate, we shall have the quantity of permanganate reduced
+by the nitric oxide.</p>
+
+<p>It must, however, be remembered that the value of solution No. 3 is
+now to be calculated on the basis of the equation KMnO<sub>2</sub> + NO =
+KNO<sub>3</sub> + MnO<sub>2</sub>. One molecule of permanganate equals one molecule of
+nitric oxide when manganous sulphate is used, since no part of the
+permanganate employed in this method is reduced below the superoxide
+condition. In other words, solution No. 3 now represents only
+three-fifths as much nitric acid as it does when oxalic acid is used.</p>
+
+<p>The results obtained by this method were moderately satisfactory, but
+not quite so exact as those obtained when oxalic acid was used. A
+series of four determinations gave differences, between the volumes of
+permanganate calculated and used, of 0.05 to 0.15 c.c.</p>
+
+<p>The principal objection to the method lies in the difficulty of
+determining, in the presence of the brown oxide of manganese, the
+exact point at which the oxidation is complete.</p>
+
+<p>The carbon dioxide generator, A, was devised by us to take the place
+of the ordinary generators, in which marble is used. We have found
+that a submersion of twenty hours in boiling water does not suffice to
+completely remove the air which, as is well known, is contained in
+ordinary marble; hence some other substance must be employed as a
+source of the gas. In the apparatus which we are about to describe,
+the acid carbonate of sodium is used.</p>
+
+<p>It consists of a long, narrow cylinder (450 x 60 mm.); a tightly
+fitting rubber stopper, through which three tubes pass, as shown in
+the figure; a small cylinder, F, containing mercury; and a sulphuric
+acid reservoir, G.</p>
+
+<p>The tube, <i>g</i>, is drawn out to a fine point at the end and curved, so
+that the acid which is delivered into A falls upon and runs down the
+outside of the tube. The tube, h, dips under the mercury in F. G and
+<i>g</i> are connected by means of a long piece of rubber tubing which is
+supplied with a screw pinch cock.</p>
+
+<p>The apparatus is made to give any required pressure by raising or
+lowering G and F; but the elevation of G, as compared with that of F,
+should always be such that the gas will force its way through h rather
+than g. The upper part of the cylinder, F, is filled with cotton wool
+to prevent loss of mercury by spattering.</p>
+
+<p>The material placed in A consists of a saturated solution of acid
+carbonate of sodium, to which an excess of the solid salt has been
+added. The sulphuric acid is the ordinary dilute. The apparatus, if
+properly regulated, serves its purpose very well. The principal
+precaution to be observed in using it is to avoid a too sudden
+relieving of the pressure, which would, of course, result in the
+introduction of an unnecessarily large quantity of sulphuric acid into
+A.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art05" id="art05"></a>WATER OF CRYSTALLIZATION.</h2>
+
+<h3>By W.W.J. NICOL, M.A., D.Sc.</h3>
+
+
+<p>When a hydrated salt is dissolved, does it retain its water of
+crystallization, or does this latter cease to be distinguishable from
+the solvent water? Both views have found advocates among chemists who
+have looked at the question of solution, and both have been supported
+by arguments more or less to the point. But among the possible means
+of solving this question there is one which has entirely escaped the
+notice of those interested in the subject. And those who hold that
+water of crystallization exists in solution have been entirely
+oblivious of the fact that, while they are ready to accept the results
+of the modern science of thermo-chemistry, and to employ them to
+support their views on hydration, yet these very results, if correct,
+prove without a shadow of a doubt that water of crystallization does
+not exist in solution.</p>
+
+<p>The proof is so clear and self-evident when once one's attention is
+directed to it, that, though I intend to develop it more fully on
+another occasion, I feel that it is better to publish an outline of it
+at once.</p>
+
+<p>Thomsen has found that the heat of neutralization of the soluble bases
+of the alkalies and alkaline earths with sulphuric acid has a mean
+value of 31.150 c. within very narrow limits. When hydrochloric or
+nitric acid is employed, the value is 27.640 c., also within very
+narrow limits. Now, this agreement of the six bases in their behavior
+with sulphuric acid, much more of the seven bases with both HNO<sub>3</sub>
+and HCl, is so close that it cannot be regarded as accidental, but, in
+the words of Meyer, the heat of formation of a salt in aqueous
+solution is a quantity made up of two parts, one a constant for the
+base, the other for the acid. But of the twenty salts thus formed,
+some are anhydrous in the solid state, others have water of
+crystallization, up to ten molecules in the case of Na<sub>2</sub>SO<sub>4</sub>. If
+water of crystallization exists in solution, it will be necessary to
+suppose that this agreement is accidental, which is absurd, as a
+glance at the probabilities will show. Thomsen himself expressly
+states that he regards the dissolved state as one in which the
+conditions are comparable for all substances; this would be impossible
+if water of crystallization were present.</p>
+
+<p><a name="Page_8965" id="Page_8965"></a>A still stronger proof is afforded by the
+&quot;<i>avidity</i>&quot; of Thomsen or the &quot;<i>affinity</i>&quot; of Ostwald; both have
+worked on the subject, taking no account of water of crystallization,
+and the results, <i>e.g.</i>, for H<sub>2</sub>SO<sub>4</sub> and HCl with NaHO, where
+water of crystallization <i>may</i> come in, are entirely confirmed by
+Ostwald's results on inversion and etherification, where there can be
+no water of crystallization.</p>
+
+<p>The proof is complete, water of crystallization cannot be attached to
+the salt in solution, or if it is, no heat is evolved on union more
+than with solvent water. The alternative is to suppose that the whole
+of the above thermo-chemical results are coincidences.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art02" id="art02"></a>ALPINE FLOWERS IN THE PYRENEES.</h2>
+
+
+<p>Bagneres De Luchon, in the department of the Haute Garonne, is a gay
+town of some 5,000 inhabitants. A friend told me that he once suffered
+so much from the heat there in June, that he determined never to go to
+the Pyrenees again. We were there the second week in June, and we
+suffered more from rain and cold, and were very glad of a fire in the
+evening.</p>
+
+<p>Except to the south, in the direction of the Porte de Venasque, one of
+the chief mule passes into Spain during summer, where there are fine
+snow-capped mountains, the scenery from the town is not grand, but it
+is within easy reach of the wildest parts of the Pyrenees.</p>
+
+<p>It is the nearest town to the Maladetta, their highest point, in which
+the Garonne rises, and among whose rocks is one of the last
+strongholds of the ibex or bouquetin, the &quot;wild goat&quot; mentioned by
+Homer. Eagles and vultures are to be seen sailing about the sky near
+Luchon nearly every day, and bears, which in the Pyrenees are neither
+mythical nor formidable, descend to within a few miles of the town
+after wild strawberries, which abound there.</p>
+
+<p>We heard of two female peasants lately gathering wild strawberries who
+were suddenly confronted with competitors for the spoil in the shape
+of a she bear and two cubs. It was doubtful whether man or beast was
+the more surprised. The cubs began to growl, but their dam gave both
+of them a box on the ears for their bad manners, and led them away. As
+for flowers, the neighborhood of Luchon has the reputation, perhaps
+not undeserved, of being the most flowery part of the Pyrenees.</p>
+
+<p>We went the usual expeditions from the town, in spite of the weather,
+and I will try to remember what plants we noticed in each of them. The
+first trip was to the Vallee du Lys. In spite of the spelling, the
+name suggests lilies of the valley, but we are told that lys is an old
+word meaning water, and that the valley took its name from the number
+of cataracts, not from lilies, there.</p>
+
+<p>However this may be, a lily grows there in great profusion, and was
+just coming into flower toward the middle of June. It is the Lis de
+St. Bruno (Anthericum liliastrum), a plant worthy of giving its name
+to a valley of which it is a characteristic feature. Still more
+conspicuous at the time when we were there were the Narcissus
+poeticus, abundant all round Luchon, but already past in the low
+meadows near the town, but higher up, at an elevation of about 4,000
+ft., it was quite at its best, and whitened the ground over many
+acres.</p>
+
+<p>I looked about for varieties, but failed to detect any special
+character by which it could be referred to any of the varietal names
+given in catalogues, and concluded that it was N. poeticus pure and
+simple. Pulmonarias were abundant along the road, as also in the whole
+region of the Pyrenees, the character of the leaves varying greatly,
+some being spotless, some full of irregular white patches, others with
+well defined round spots. They varied, too, from broad heart-shaped to
+narrow lanceolate, and I soon concluded that it was hopeless to
+attempt any division of the class founded upon the leaves.</p>
+
+<p>Besides the beautiful flowers of Scabious mentioned before, a new
+feature in the meadows here was the abundance of Astrantia major. A
+pure white Hesperis matronalis was also common, but I saw no purple
+forms of it. Geranium ph&aelig;um also grew everywhere in the fields, the
+color of the flower varying a good deal. Hepaticas were not so common
+by the roadside here as at Eaux Bonnes, but are generally distributed.
+Many of them have their leaves beautifully marbled, and I selected and
+brought away a few of the best, in hopes that they may keep this
+character. I was struck everywhere by the one-crowned appearance of
+the Hepaticas, as if in their second year from seed.</p>
+
+<p>On the mountains, where they were still in flower, I did not find the
+colors mixed, but on one mountain they would be all white, on another
+all blue. I do not recollect to have seen any pink. Meconopsis
+cambrica is common in the Pyrenees. I observe that in Grenier's
+&quot;French Flora&quot; the color of the flower is given as &quot;jaune orange,&quot; but
+I never saw it either in England or in France with orange flowers till
+I saw it covering a bank by the side of the road to the Vallee du Lys.
+I was too much struck by it to delay securing a plant or two, which
+was lucky, for when we returned every flower had been gathered by some
+rival admirers.</p>
+
+<p>Another expedition from Luchon is to the Lac d'Oo. This, too, is
+famous for flowers; but especially so is a high valley called Val
+d'Esquierry, 2,000 ft. or 3,000 ft. above the village d'Oo, at which
+the carriage road ends. Botanists call this the garden of the
+Pyrenees, and, of course, I was most anxious to see it.</p>
+
+<p>The landlord of our hotel was quite enthusiastic in his description of
+the treat in store for me, enumerating a long catalogue of colors, and
+indicating with his hand, palm downward, the height from the ground at
+which I was to expect to see each color. I was afterward told that he
+had never been to the famous valley, being by no means addicted to
+climbing mountains.</p>
+
+<p>During the first part of the drive from Luchon we saw hanging from the
+rocks by the roadside large masses of Saponaria ocymoides, varying
+much in the shade of color of the flowers. This is a plant which I
+find it better to grow from cuttings than from seed. The best shades
+of color are in this way preserved, and the plants are more flowery
+and less straggling. As we got near the end of the carriage road, the
+meadows became more crowded with flowers known in England only in
+gardens.</p>
+
+<p>Besides such plants as Geranium pyrenaicum growing everywhere on the
+banks, the fields were full of a light purple geranium&mdash;I think
+sylvaticum. Here, too, I noticed Meconopsis cambrica with orange
+flowers. Narcissus poeticus was also there, and so were some splendid
+thistles, large and rich in color. But the most remarkable part of the
+coloring in the meadows was produced by different shades of Viola
+cornuta carpeting the ground. We noticed this plant in many parts of
+the Pyrenees, but here especially.</p>
+
+<p>From the end of the road I started with a guide for the promised
+garden of the Val d'Esquierry. By the side of the steep and winding
+path I noticed Ramondia pyrenaica&mdash;the only place I saw it in the
+Luchon district. Other notable plants were a quantity of Anemone
+alpina of dwarf growth and very large flowers, covering a green knoll
+near a stream. A little beyond, Aster alpinus was in flower, of a
+bright color, which I can never get it to show in gardens. These, with
+the exception of a few saxifrages and daffodils of the variety
+muticus, were about the last flowers I saw there.</p>
+
+<p class="center"><a href="./images/15.png"><img src="./images/15_th.png" alt="GROUP OF ALPINE FLOWERS" /></a><br /> GROUP OF ALPINE FLOWERS</p>
+
+<p>Promise of flowers there was in abundance. Aconites, I suppose
+napellus, and also that form of A. lycoctonum with the large leaves
+known as pyrenaicum, were just enough grown to recognize. The large
+white Asphodel, called by French botanists A. albus, but better known
+in gardens as A. ramosus, which grows everywhere in the Pyrenees, and
+the coarse shoots of Gentiana lutea were just showing.</p>
+
+<p>Further on the daffodils were only just putting their noses through
+the yellow dead grass, which the snow had hardly left and was again
+beginning to whiten, for the rain, which had been coming down in
+torrents ever since I left the carriage and had wet me through, had
+now changed to snow. Still I went on, in spite of the bitter cold,
+hoping that I should come to some hyperborean region where the flowers
+would be all bright; but my guide at last undeceived me, and convinced
+me that we were far too early, so we went down again, wiser and
+sadder, and I advise my friends who wish to see the Val d'Esquierry in
+its beauty not to visit it before July at the earliest.</p>
+
+<p>I have still one mountain walk to describe, a far more successful one,
+but it must be deferred till another week.&mdash;<i>C. Wolley Dod, in the
+Garden.</i></p>
+
+<hr />
+
+
+<p>Turtle shells may be softened by hot water, and if compressed in this
+state by screws in iron or brass moulds, may be bent into any shape,
+the moulds being then plunged into cold water.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art01" id="art01"></a>A CENTURY PLANT IN BLOOM.</h2>
+
+
+<p>A huge agave, or century plant, is now blooming at Auburn, N.Y. A few
+days ago the great plant became tinged with a delicate yellowish-white
+color, as its 4,000 buds began to develop into the full-blown flowers,
+whose penetrating fragrance, not unlike that of the pond lily, now
+attracts swarms of bees and other insects. The plant was purchased in
+1837 by the owner, and was then twelve years old. For half a century
+the agave has lain around his greenhouses in company with several
+others, and no special care has been taken of it, except to protect it
+somehow in winter, that it might be fresh for the next summer's
+growth. The plant has always been a hardy specimen, and required
+little care. Its whole life, now speedily approaching a termination in
+the fulfillment of the end of its existence&mdash;flowering&mdash;has been a
+sluggish course. Its growth has been steady and its development
+gradual. Occasionally it has thrust out a spiked leaf until, in size,
+it became greater than its fellow plants and took on the likeness of
+an enormous cabbage which had been arrested in its development and
+failed to attain perfection. Early last April its appearance began to
+undergo a decided change. Its resemblance to a cabbage lessened, and
+it began to look like a giant asparagus plant. On April 12, the great
+fleshy leaves, massed together so as to impress the imprint of their
+spines upon one another, began to unfold, and a thick, succulent bud
+burst up amid the leaves. Slowly the stalk developed from the bud and
+assumed gigantic proportions. Green scales appeared in regular
+arrangement about the stalk, marking the points from which lateral
+branches were to spring. The thick stalk, tender and brittle at first
+as new asparagus, became tough and hard enough to resist a knife, and
+its surface assumed the gritty character of the leaves of the plant.
+The low roof of the hothouse became an obstruction to further growth,
+and had to be removed. Lateral limbs were, at a later period, thrust
+out in great numbers, each of them bearing small branches, as do
+strawberry plants, on which hang sprays of buds in bunches of from
+three to ten, making in all many hundreds, all waiting for the
+completion and blooming of the topmost buds. The inflorescence of the
+century plant is peculiar, and the appearance of flowers on the lower
+branches may be simultaneous with, or consecutive to, the blossoming
+on the upper limbs. With the appearance of the lateral outshoots the
+great aloe lost its likeness to asparagus, and at present bears
+resemblance to an immense candelabra. The plant is now fully matured,
+and has a height of twenty-seven feet. There are thirty-three branches
+on the main stem, and, by actual count, one of the lateral limbs was
+found to bear 273 perfect buds, some of whose green sepals have
+spread, revealing the yellowish-white petals and essential parts of
+the plant. The ample panicles crowded with curious blossoms are, as,
+indeed, the Greek name of the plant&mdash;agave&mdash;signifies, wonderful.</p>
+
+<p>There is a pathetic view to be taken of the great plant's present
+condition. For years it has been preparing to flower, and the shoot it
+has sent up is the dying effort. The blossoms carry in them the life
+of new plants, and the old plant dies in giving them birth. It is
+commonly supposed that this plant, the <i>Agave Americana</i>, or American
+aloe, blooms only at the end of 100 years, hence the common name
+century plant.</p>
+
+<p>Only two plants are on record among the floriculturists as having
+bloomed in New York State. Thirty years ago, a century plant, of which
+the Casey aloe was a slip, flowered in the greenhouses of the Van
+Rensselaer family at Albany. In 1869, a second plant blossomed at
+Rochester. At present, two aloes, one at Albany, the other at
+Brooklyn, are reported as giving evidences of approaching maturity.
+They are pronounced not American aloes, or century plants, but <i>Agave
+Virginica</i>, a plant of the same family commonly found in sterile soil
+from Virginia to Illinois and south, and blossoming much more
+frequently. In Mexico the century plant is turned to practical account
+and made a profitable investment to its owners. After the scape has
+reached its full growth it is hewn down, and the sap, which fills the
+hollow at its base, is ladled out and converted by fermentation into
+&quot;agave wine,&quot; or &quot;pulque,&quot; the favorite drink of the Mexicans. This
+pulque, or octli, has an acid resembling that of cider, and a very
+disagreeable odor, but the taste is cooling and refreshing. A brandy
+distilled from pulque is called &quot;aquardiente,&quot; or &quot;mexical.&quot; The
+plant, by tapping, can be made to yield a quart of sap daily. The
+fibers of the leaves when dried furnish a coarse thread known as Pita
+flax, and when green are used in Mexico as fodder for cattle. Razor
+strops or hones are also made from the leaves, which contain an
+abundance of silica and give rise to a very sharp edge on a knife
+applied with friction across the surface of the dried leaf.</p>
+
+<hr />
+
+
+
+
+<h2><a name="art10" id="art10"></a><a name="Page_8966" id="Page_8966"></a>CREOSOTE A SPECIFIC FOR ERYSIPELAS.</h2>
+
+
+<p>Time was when the advocate of a specific was laughed at by the
+scientific world, but since it is known that so many forms of disease
+are the direct result of some kind of germ life, it is no longer a
+misnomer to call a medicine which will certainly and always destroy
+the germ which produces so many forms of disease a specific.</p>
+
+<p>In the light of this definition, founded upon the experience of forty
+years' successful practice in treating this form of disease with
+creosote, the writer is prepared to indorse the heading of this
+article. Having used all the different remedies ordinarily prescribed,
+they have long since been laid aside, and this one used in all forms
+of the disease exclusively, and with uniform success.</p>
+
+<p>In 1863 it was the writer's fortune to spend several weeks in a
+military hospital in Memphis as a volunteer surgeon, under the
+direction of Dr. Lord. In conversation with him, the use of this
+article was mentioned, which appeared new to him, and a case was put
+under treatment with it, with such prompt favorable results as to
+elicit his hearty commendation, and, at his suggestion,
+Surgeon-General Hammond was informed of it.</p>
+
+<p>All injuries, of whatever kind, have been treated with dressings of
+this remedy, and where this has been done from the first to last, in
+no instance has there been an attack of erysipelas.</p>
+
+<p>The usual manner of application was in solution of six to twenty drops
+to the ounce of water, keeping the parts covered with cloths
+constantly wet with it. In ulcers or wounds it may be used in the form
+of a poultice, by stirring ground elm into the solution, the strength
+to be regulated according to the virulence of the attack. Ordinarily,
+ten drops to the ounce is strong enough for the cutaneous form of the
+disease and in dressings for wounds or recent injuries. If the
+inflammation threatens to spread rapidly, it should be increased to
+twenty or more drops to the ounce of water.</p>
+
+<p>The antiseptic properties of this remedy render it of additional
+value, as it will certainly destroy the tendency to unhealthy
+suppuration, and thus prevent septic&aelig;mia.</p>
+
+<p>In the treatment of hundreds of cases of erysipelas but one fatal case
+has occurred, and that one in an old and depraved system. In the less
+violent attacks no other remedy was used, but where constitutional
+treatment was indicated, the usual appropriate tonics were prescribed.</p>
+
+<p>There is no question in my mind but that creosote is as much a
+specific in erysipelas as quinine is in intermittent fever, and may be
+used with as much confidence.&mdash;<i>St. Louis Med. Jour.</i></p>
+
+<hr />
+
+
+
+
+<h2><a name="art09" id="art09"></a>A NEW APPARATUS FOR THE STUDY OF CARDIAC DRUGS.</h2>
+
+<h3>By WILLIAM GILMAN THOMPSON, M.D., New York.</h3>
+
+
+<p>The apparatus was devised by Mr. R.D. Gray (the inventor of the
+ingenious &quot;vest camera&quot; and other photographic improvements) and by
+myself. I described what was required and suggested various
+modifications and improvements, but the mechanical details were worked
+out exclusively by him. To test the rapidity of the camera, we
+photographed a &quot;horse-timer&quot; clock, with a dial marking quarter
+seconds, and succeeded in taking five distinct photographs in half a
+second with <i>one</i> lens, which has never before been accomplished
+excepting by Professor Marey,<a name="FNanchor_12" id="FNanchor_12"></a><a href="#Footnote_12"><sup>1</sup></a> at the College de France, who has
+taken successive views of flying birds, falling balls, etc., with one
+lens at a very rapid rate. His camera was unknown to me until after
+mine was constructed, so that as a success in photography alone the
+work is interesting.</p>
+
+<p>The camera consists of a circular brass box, 5½ inches in diameter and
+1¼ inches deep, containing a circular vulcanite shutter with two
+apertures, behind which is placed a circular dry plate. Both plate and
+shutter are revolved in opposite directions to each other by a simple
+arrangement of four cogged wheels moved by a single crank. The box is
+perforated at one side by a circular opening, 1¾ inches in diameter,
+from the margin of which projects at a right angle a long brass tube
+(Fig. 1), which carries the lens. In Fig. 2 the lid of the box has
+been removed, and the bottom of the box, with the wheels, springs, and
+partially closed shutter, is presented. The lid is double&mdash;that is, it
+is a flat box in itself. It contains nothing but the dry plate,
+supported at its center upon a small brass disk, against which disk it
+is firmly pressed by a pivot attached to a spring fastened in the lid.
+The aperture in one side of this double lid, which corresponds with
+that seen in the floor of the box, may be closed by a slide, so that
+the lid containing the plate can be removed like an ordinary plate
+holder and carried to a dark room, where it is opened and the plate is
+changed. When the lid is replaced this slide is removed, and as the
+shutter is made to revolve, the light falls upon whatever portion of
+the dry plate happens to be opposite the opening.</p>
+
+<p>By reference to Fig. 2, it will be seen that when the large wheel
+which projects outside of the box is revolved by a crank, it turns the
+small ratchet wheel, which bears an eccentric pawl. (The crank has
+been removed in Fig. 2; it is seen in Fig. 1.) The central wheel has
+only six cogs. The pawl is pressed into one of these cogs by a spring.
+It pushes the central wheel around one-sixth of its circumference,
+when it returns to be pressed into the next cog. While the pawl
+returns, it necessarily leaves the central wheel at rest, and whatever
+momentum this wheel carries is checked by a simple stop pressed by a
+spring upon the opposite side. The central wheel carries a square
+axle, which projects through a small hole in the center of the double
+lid and fits into the brass disk before alluded to, causing the disk
+to revolve with the axle. The disk is covered by rubber cloth; and as
+the dry plate is pressed firmly against the rubber surface by the
+spring in the lid, the plate adheres to the rubber and revolves with
+the disk. Thus every complete revolution of the central wheel in the
+floor of the box carries with it the dry plate, stops it, and moves it
+on again six times. The velocity of revolution of the plate is only
+limited by the rapidity with which one can turn the crank.</p>
+
+<p>The shutter is revolved in the opposite direction by a wheel whose
+cogs are seen fitting into those of the little wheel carrying the
+eccentric pawl.</p>
+
+<p class="center"><a href="./images/16a.png"><img src="./images/16a_th.png" alt="FIG. 1.&mdash;THE CAMERA MOUNTED." /></a><br /> FIG. 1.&mdash;THE CAMERA MOUNTED.</p>
+
+<p>The two apertures in the shutter are so placed that at the instant of
+exposure of the plate it is momentarily at rest, while the plate when
+moving is covered by the shutters. This arrangement prevents vibration
+of the plate and blurring of the image. The camera is mounted by two
+lateral axles with screw clamps upon two iron stands, such as are in
+common use in chemical laboratories. A brass rod attached to the tube
+steadies it, and allows it to be screwed fast at any angle
+corresponding to the angle at which the heart is placed. It is thus
+easy to put a manometer tube in the femoral artery of an animal, bend
+it up alongside of the exposed heart, and simultaneously photograph
+the cardiac contraction and the degree of rise of the fluid in the
+manometer(!). The tube is arranged like the draw tube of a microscope.
+It is made long, so as to admit of taking small hearts at life-size.
+The stand carries a support for the frog or other animal to be
+experimented upon, and a bottle of physiological salt solution kept
+warm by a spirit lamp beneath.</p>
+
+<p class="center"><img src="./images/16b.png" alt="FIG. 2.&mdash;INTERIOR OF THE CAMERA." /><br /> FIG. 2.&mdash;INTERIOR OF THE CAMERA.</p>
+
+<p>The whole apparatus is readily packed in a small space. I have already
+taken a number of photographs of various hearts and intestines with
+it, and the contraction of the heart of the frog produced by
+<i>Strophanthus hispidus</i>, the new cardiac stimulant, is seen in Fig. 3,
+taken by this new instrument. The apparatus has the great advantage
+that six photographs of a single cardiac pulsation, or of any muscular
+contraction, may be easily taken in less than one second, or, by
+simply turning the crank slower, they may be taken at any desired rate
+to keep pace with the rhythm of the heart. The second hand of a watch
+may be placed in the field of view and simultaneously photographed
+with the heart, so that there can be no question about the series of
+photographs all belonging to one pulsation.</p>
+
+<p class="center"><img src="./images/16c.png" alt="FIG. 3.&mdash;PHOTOGRAPHS OF THE HEART IN MOTION." />
+<br />FIG. 3.&mdash;PHOTOGRAPHS OF THE HEART IN MOTION.<br /><br />
+1, Normal diastole; 2, auricular systole; 3, ventricular systole. 1,
+2, 3 were taken in a half second; 4, 5, 6, same as 1, 2, 3, after
+injection of toxic dose of Strophanthus hispidus. 4, 5, 6 were taken
+in a half second. The pulse rate was 74.</p>
+
+<p>I have already called attention<a name="FNanchor_13" id="FNanchor_13"></a><a href="#Footnote_13"><sup>2</sup></a> to the ease with which these
+photographs are enlarged for lecture room demonstration, either on
+paper or in a stereopticon, and the ease with which they may be
+reproduced in print to illustrate the action of drugs.</p>
+
+
+<p><a name="Footnote_12" id="Footnote_12"></a><a href="#FNanchor_12">[1]</a></p><div class="note"><p>La Methode Graphique (Supplement), Paris, 1885.</p></div>
+
+<p><a name="Footnote_13" id="Footnote_13"></a><a href="#FNanchor_13">[2]</a></p><div class="note"><p>
+<i>Medical Record</i>, loc. cit.; Recent Advances in Methods
+of Studying the Heart, <i>Medical Press</i>, Buffalo, March 1, 1886, p.
+234; Instantaneous Photographs of the Heart, Johns Hopkins University
+Circulars, March, 1886, p. 60.</p></div>
+
+<hr />
+
+
+<p>A CATALOGUE containing brief notices of many important scientific
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+this office.</p>
+
+<hr />
+
+
+<h3>THE</h3>
+
+<h2>Scientific American Supplement.</h2>
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+1, 1876, can be had. Price, 10 cents each.</p>
+
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+
+<p class="center"><b>MUNN&amp; CO., Publishers, <br />361 Broadway, New York, N. Y.</b></p>
+
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+
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+
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+of the Patentee. By the immense circulation thus given, public
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+
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+
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+
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+
+<p class="center">Branch Office, 622 and 624 F St., Washington, D.C.</p>
+
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+561, October 2, 1886, by Various
+
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@@ -0,0 +1,5282 @@
+The Project Gutenberg EBook of Scientific American Supplement, No. 561,
+October 2, 1886, 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. 561, October 2, 1886
+
+Author: Various
+
+Release Date: July 27, 2005 [EBook #16360]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN ***
+
+
+
+
+Produced by Juliet Sutherland, Jeannie Howse, Victoria
+Woosley and the Online Distributed Proofreading Team at
+www.pgdp.net
+
+
+
+
+
+[Illustration]
+
+
+
+
+SCIENTIFIC AMERICAN SUPPLEMENT NO. 561
+
+
+
+
+NEW YORK, OCTOBER 2, 1886
+
+Scientific American Supplement. Vol. XXII., No. 561.
+
+Scientific American established 1845
+
+Scientific American Supplement, $5 a year.
+
+Scientific American and Supplement, $7 a year.
+
+       *       *       *       *       *
+
+
+
+
+TABLE OF CONTENTS.
+
+
+I.    BOTANY.--A Century Plant in Bloom.--Interesting account of
+      the recent blossoming of an _Agave Americana_ at
+      Auburn, N.Y.                                                8965
+
+      Alpine Flowers in the Pyrenees.--1 illustration.            8965
+
+II.   CHEMISTRY.--Probable Isolation of Fluorine.--Decomposition
+      of hydrofluoric acid by an electric current.--By M.H.
+      MOISSAN.--Production of a new body, possibly fluorine, or
+      perfluoride of hydrogen.                                    8963
+
+      The Determination of Nitric Acid by the Absorption of Nitric
+      Oxide in a Standard Solution of Permanganate of Potash.--
+      By H.N. MORSE and A.F. LINN. Full description of a new and
+      important volumetric determination.--1 illustration.        8964
+
+      Water of Crystallization.--By W.W.J. NICOL, M.A., D.Sc.--
+      Discussion of the state of water of crystallization in a
+      salt in solution.                                           8964
+
+III.  ENGINEERING.--Combustion, Fire Boxes, and Steam Boilers--By
+      JOHN A. COLEMAN.--Address before the June Convention of
+      the Master Mechanics' Association.                          8953
+
+      Compound Hydraulic Presses.--Different forms of presses
+      designed for pressing bales for shipment.--Very fully
+      illustrated by 8 figures.                                   8951
+
+      Examination Papers in General Construction.--Eighty-six
+      questions in engineering propounded by the civil service
+      examiners of New York city.                                 8956
+
+IV.   MEDICINE AND PHYSIOLOGY.--A New Apparatus for the Study of
+      Cardiac Drugs.--By WILLIAM GILMAN THOMPSON, M.D.--Ingenious
+      application of instantaneous photography to the study
+      of heart movements.--Apparatus and views produced.--3
+      illustrations.                                              8966
+
+      Creosote a Specific for Erysipelas,--A new cure for this
+      complaint.                                                  8966
+
+V.    METALLURGY.--Primitive Iron Manufacture.--Iron furnace
+      and blowing apparatus in use in Bengal.--2 illustrations.   8962
+
+VI.   MINING ENGINEERING.--The Catastrophe at Chancelade.--
+      Application of photography to investigating mine disasters.
+      --4 illustrations.                                          8962
+
+VII.  MISCELLANEOUS.--Celebration of the 500th Anniversary of the
+      University of Heidelberg. August, 1886.                     8957
+
+      Useful Bags and How to Make Them.--Interesting paper on the
+      trunk makers' art.--4 illustrations.                        8960
+
+VIII. NAVAL ENGINEERING.--Atlantic Steamers.--By W. JOHN.--
+      Exhaustive comparison of representative Atlantic liners
+      and war ships.--3 illustrations.                            8954
+
+      Jet Propellers.--Hydraulic propulsion of vessels.--
+      Mathematical examination of this subject.                   8951
+
+IX.   ORDNANCE.--The New Army Gun.--Description of the 8-inch
+      steel gun as manufactured at the West Point, N.Y.,
+      Foundry.--1 illustration.                                   8952
+
+X.    PHYSICS.--A New Thermo Regulator.--1 illustration.          8959
+
+      Cohesion and Cohesion Figures.--By WILLIAM ACKROYD,
+      F.I.C.--Laws of vortex rings examined, and relation of
+      solubility to cohesion.                                     8963
+
+      Pipette for taking the Density of Liquids.--Apparatus and
+      calculations for use.--1 illustration.                      8959
+
+XI.   TECHNOLOGY.--Impurities in Photographic Chemicals, and
+      Tests for Same.--Table referred to in a paper read before
+      the Birmingham Photographic Society by G.M. Jones, M.P.S.   8957
+
+      Molasses, how made.--Work on Plantations Graphically
+      Described.*                                                 8961
+
+      Optical errors and human mistakes.--By ERNST GUNDLACH.--On
+      the examination of optical glasses.--A paper read before
+      the Buffalo meeting of the A.A.A.S.                         8963
+
+      Soap.--By HENRY LEFFMANN, Ph.D.                             8962
+
+      Somzee's New Gas Burners.--Interesting description of
+      regenerative burners.--9 figures.                           8958
+
+      The Clamond Gas Burner.--Of value as a supplement to the
+      above named article, describing an incandescent burner.
+      --1 illustration.                                           8959
+
+      Wood Oil.--A new industry worked on the large scale in
+      Sweden.                                                     8962
+
+
+         * Transcriber's Note: "Work on Plantations..." was
+           originally part of TOC entry "Optical Errors..."
+
+
+       *       *       *       *       *
+
+
+
+
+COMPOUND HYDRAULIC PRESSES.
+
+
+In a hydraulic packing press, the work done by the ram during one
+stroke may be roughly divided into two periods, in the first of which
+the resistance, although gradually increasing, may be called light,
+while in the second the resistance is heavy. The former of these two
+periods embraces the greater part of the stroke, and it is only a
+small proportion at the end which requires the exercise of the full
+power of the press to bring the material to the determined degree of
+consolidation. Consequently, if a hydraulic press is to be worked so
+as to waste no time, it requires to be provided with means by which
+its table may be made to rise rapidly during the portion of the stroke
+when the resistance is small, and afterward more slowly when the
+entire power of the pumps is being expended upon the final squeeze.
+Many methods of obtaining this end have been devised, and are in
+common use both here and abroad. It is, however, more particularly in
+the packing of raw material that such appliances are useful, since the
+goods pressed into bales in this country are not usually of a very
+yielding nature, and consequently do not require a long stroke to
+bring them to a high state of compression. In India and Egypt, from
+whence cotton is sent in bales, presses must have a long stroke; and
+unless they can be worked rapidly, a very considerable amount of plant
+is required to get through a moderate quantity of work. To meet the
+necessities of these countries, Mr. Watson has devised several forms
+of press in which not only is the table made to rise rapidly through
+the greater part of its stroke, but the rams are kept almost
+constantly in motion, so that the time occupied in filling the box
+with raw cotton and in placing the ties round the bales is not lost.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 1 and 2.]
+
+We illustrate four forms of Mr. Watson's presses, Fig. 1 being an
+earlier construction, which, although very rapid at the date at which
+it was brought out, has been far surpassed in celerity by the
+arrangements shown in Figs. 3 to 8. It was introduced in 1873, and
+forty-three presses according to this design were sent to India by the
+makers, Messrs. Fawcett, Preston & Co., of Phoenix Foundry,
+Liverpool, between that year and 1880. Four presses of this kind are
+worked by one engine, having a cylinder 20 in. by 3 ft. stroke, and
+driving eighteen to twenty pumps of varying diameter and short stroke.
+The press has two long-stroke rams, LL, of small diameter, to compress
+the loose material, and two short-stroke rams, FF, of large diameter,
+to give the final squeeze. These two pairs of rams act alternately,
+the one pair being idle while the other is in operation. The lashing
+of the bale takes place while the larger rams are in action, the bale
+being supported on the grid, B, which is pushed under it through
+grooves formed in the press-head, S (Fig. 1). When the grid is in
+place the press-head can be lowered, and the box be filled, while the
+bale is receiving its final squeeze from the inverted rams above.
+
+In Figs. 1 and 2 the press is shown in the position it would occupy if
+the bale, M, were just completed and ready to be pushed out, and the
+box, N, were full of material. The filling doors, CC, are shown turned
+back level with the floor, the main doors, AA, are open, as are also
+the end doors, KK, to admit the men to fasten up the bale. If water be
+admitted to the subsidiary cylinder, H, the head, G, and two rams, FF,
+will be raised, and then the bale, M, can be thrown out finished. All
+the doors are now closed and water admitted to the rams, LL. These
+immediately rise, pushing the contents of the box, N, before them, and
+compressing them until the table, S, reaches the level of the grid, B.
+At this moment the tappet rod, D, shuts off the water, and withdraws
+the bolt of the doors, AA, which fly open. The grid, B (Fig. 2), is
+then run through the grooves in the press-head, S, and the rams, LL,
+are allowed to descend ready for a baling cloth to be inserted through
+the doors, EE, and for the box, N, to be refilled. At the same time
+the head, G, comes down on to the bale and compresses it still
+further, while the men are at work lashing it. When the material is in
+hanks, like jute, the rams, LL, are lowered slowly, while a man
+standing inside the box, at about the level of the floor, packs the
+material neatly on the table.
+
+These presses can be worked with great rapidity, the average output
+during a day varying from 21 to 28 bales an hour. The consumption of
+coal per bale is 9 lb. of Bengal coal, in value about 3/4d. The density
+of the cotton bales produced is about 45 lb. per cubic foot, 400 lb.
+measuring a little under 9 cubic feet for shipment. In the case of
+jute or jute roots, the same weight occupies 10 cubic feet on an
+average. But rapid as this press is in action, the necessities of
+recent business in India have called for still more expeditious
+working, and to meet this demand Mr. Watson produced his compound
+press, in which the economy of time is carried to its utmost
+development. By the addition of a second pair of long-stroke rams the
+output of the press has been trebled, being raised to 80 bales per
+hour. To effect this, there is one pair of powerful rams, as in the
+press just described, but two pairs of the long-stroke rams. Further,
+each pair of the small-diameter rams is fitted with two boxes, one of
+which is always being filled while the other is being pressed. The
+rams in rising compress the material into a small cell or box,
+situated above the box in which raw cotton is thrown. On the top of
+the ram head there is a loose lashing plate, which, at the finish of
+the action of the rams, is locked in the cell by bolts actuated by a
+suitable locking gear. While in this cell the bale has the lashing
+ropes put round it, and then it is placed under the large rams for the
+final squeeze, during which the ties or ropes are permanently secured.
+Thus neither of the small presses has even to wait while its box is
+being filled, or while the previously pressed bale is being lashed.
+Even in the large press, when the ties are finally fastened, the time
+occupied does not exceed three-quarters of a minute, and is often much
+less.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 3 and 4.]
+
+This press is shown in Figs. 3 and 4. The small rams are arranged at
+either side of the large ones, which, in this case, are not inverted.
+To each of the smaller presses there is a pair of boxes mounted on a
+vertical column, around which they can revolve to bring either box
+over the rain head. When the left hand rams rise, the material is
+delivered into the cell, D, which previously has had its doors (Fig.
+4) closed. To permit of the cell, D, being moved out of the way, it is
+mounted so that it can revolve on one of the columns of the main
+press, first into the position shown at B (Fig. 4), and afterward to C
+(Fig. 3). While at D, the bale in the cell (called from its
+construction a revolver) is partly lashed, the ties or ropes being put
+into position. It is then rotated until it comes over the large rams,
+where the bale is still more compressed and secured.
+
+It must be admitted that this press provides for the greatest possible
+economy of time, and for the largest output, for the capital employed,
+which can be attained. The rams and the men are constantly in action,
+and not a single moment is lost. For filling each box 78 seconds are
+allowed, and there is ample time for the preliminary lashing.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 5 and 6.]
+
+Figs. 5 and 6 show a modification of this press, designed to turn out
+sixty bales per hour. It has only one set of long-stroke rams, with
+three revolvers. The bale receives its preliminary lashing while in
+the position, B (Fig. 6). Fifty-three seconds are available for
+filling the box, and the same time for the preliminary lashing. It is
+found, however, that three-quarters of a minute is sufficient for the
+complete hooping of a bale.
+
+[Illustration: COMPOUND HYDRAULIC PRESS. FIGS. 7 and 8.]
+
+Figs. 7 and 8 show a similar press intended for jute pressing. This
+has only one box, which is fixed, as the material has to be packed in
+an orderly manner. Its speed is sixty bales an hour.--_Engineering._
+
+       *       *       *       *       *
+
+
+
+
+JET PROPELLERS.--HYDRAULIC PROPULSION OF VESSELS.
+
+
+Certain mechanical devices appear to exercise a remarkable influence
+on some minds, and engineers are blamed for not adopting them, in no
+very measured terms in some cases. It is not in any way necessary that
+these devices should have been invented by the men who advocate their
+adoption, in order to secure that advocacy. The intrinsic attractions
+of the scheme suffice to evoke eulogy; and engineers sometimes find it
+very difficult to make those who believe in such devices understand
+that there are valid reasons standing in the way of their adoption.
+One such device is hydraulic propulsion. A correspondent in a recent
+impression suggested its immediate and extended use in yachts at all
+events, and we willingly published his letter, because the system does
+no doubt lend itself very freely to adoption for a particular class of
+yachts, namely, those provided with auxiliary power only. But because
+this is the case it must not be assumed that the jet propeller is
+better than screw or paddle-wheel propulsion; and it is just as well,
+before, correspondence extends further, that we should explain why and
+in what way it is not satisfactory. The arguments to be urged in favor
+of hydraulic propulsion are many and cogent; but it will not fail to
+strike our readers, we think, that all these arguments refer, not to
+the efficiency of the system, but to its convenience. A ship with a
+hydraulic propeller can sail without let or hindrance; a powerful pump
+is provided, which will deal with an enormous leak, and so on. If all
+the good things which hydraulic propulsion promises could be had
+combined with a fair efficiency, then the days of the screw propeller
+and the paddle wheel would be numbered; but the efficiency of the
+hydraulic propeller is very low, and we hope to make the reason why it
+is low intelligible to readers who are ignorant of mathematics. Those
+who are not ignorant of them will find no difficulty in applying them
+to what we have to say, and arriving at similar conclusions in a
+different way.
+
+Professor Greenhill has advanced in our pages a new theory of the
+screw propeller. As the series of papers in which he puts forward his
+theory is not complete, we shall not in any way criticise it; but we
+must point out that the view he takes is not that taken by other
+writers and reasoners on the subject, and in any case it will not
+apply to hydraulic propulsion. For these reasons we shall adhere in
+what we are about to advance to the propositions laid down by
+Professor Rankine, as the exponent of the hitherto received theory of
+the whole subject. When a screw or paddle wheel is put in motion, a
+body of water is driven astern and the ship is driven ahead. Water,
+from its excessive mobility, is incapable of giving any resistance to
+the screw or paddle save that due to its inertia. If, for example, we
+conceive of the existence of a sea without any inertia, then we can
+readily understand that the water composing such a sea would offer no
+resistance to being pushed astern by paddle or screw. When a gun is
+fired, the weapon moves in one direction--this is called its
+recoil--while the shot moves in another direction. The same
+principal--_pace_ Professor Greenhill--operates to cause the movement
+of a ship. The water is driven in one direction, the ship in another.
+Now, Professor Rankine has laid down the proposition that, other
+things being equal, that propeller must be most efficient which sends
+the largest quantity of water astern at the slowest speed. This is a
+very important proposition, and it should be fully grasped and
+understood in all its bearings. The reason why of it is very simple.
+Returning for a moment to our gun, we see that a certain amount of
+work is done on it in causing it to recoil; but the whole of the work
+done by the powder is, other things being equal, a constant quantity.
+The sum of the work done on the shot and on the gun in causing their
+motions is equal to the energy expended by the powder, consequently
+the more work we do on the gun, the less is available for the shot. It
+can be shown that, if the gun weighed no more than the shot, when the
+charge was ignited the gun and the shot would proceed in opposite
+directions at similar velocities--very much less than that which the
+shot would have had had the gun been held fast, and very much greater
+than the gun would have had if its weight were, as is usually the
+case, much in excess of that of the shot. In like manner, part of the
+work of a steam engine is done in driving the ship ahead, and part in
+pushing the water astern. An increase in the weight of water is
+equivalent to an augmentation in the weight of our gun and its
+carriage--of all that, in short, takes part in the recoil.
+
+But, it will be urged, it is just the same thing to drive a large body
+of water astern at a slow speed as a small body at a high speed. This
+is the favorite fallacy of the advocates of hydraulic propulsion. The
+turbine or centrifugal pump put into the ship drives astern through
+the nozzles at each side a comparatively small body of water at a very
+high velocity. In some early experiments we believe that a velocity of
+88 ft. per second, or 60 miles an hour, was maintained. A screw
+propeller operating with an enormously larger blade area than any pump
+can have, drives astern at very slow speed a vast weight of water at
+every revolution; therefore, unless it can be shown that the result is
+the same whether we use high speed and small quantities or low speed
+and large quantities, the case of the hydraulic propeller is hopeless.
+But this cannot be done. It is a fact, on the contrary, that the work
+wasted on the water increases in a very rapid ratio with its speed.
+The work stored up in the moving water is expressed in foot pounds by
+the formula
+
+  W v squared / 2g
+
+where W stands for the weight of the water, and v for its velocity.
+But the work stored in the water must have been derived from the
+engine; consequently the waste of engine power augments, not in the
+ratio of the speed of the water, but in the ratio of the square of its
+speed. Thus if a screw sends 100 tons of water astern at a speed of 10
+ft. per second per second, the work wasted will be 156 foot tons per
+second in round numbers. If a hydraulic propeller sent 10 tons astern
+at 100 ft. per second per second, the work done on it would be 1,562
+foot tons per second, or ten times as much. But the reaction effort,
+or thrust on the ship, would be the same in both cases. The waste of
+energy would, under such circumstances, be ten times as great with the
+hydraulic propeller as with the screw. In other words, the slip would
+be magnified in that proportion. Of course, it will be understood that
+we are not taking into account resistances, and defects proper to the
+screw, from which hydraulic propulsion is free, nor are we considering
+certain drawbacks to the efficiency of the hydraulic propeller, from
+which the screw is exempt; all that we are dealing with is the waste
+of power in the shape of work done in moving water astern which we do
+not want to move, but cannot help moving. If our readers have followed
+us so far, they will now understand the bearing of Rankine's
+proposition, that that propeller is best which moves the greatest
+quantity of water astern at the slowest speed. The weight of water
+moved is one factor of the thrust, and consequently the greater that
+weight, other things being equal, the greater the propelling force
+brought to bear on the ship.
+
+It may be urged, and with propriety, that the results obtained in
+practice with the jet propeller are more favorable than our reasoning
+would indicate as possible; but it will be seen that we have taken no
+notice of conditions which seriously affect the performance of a
+screw. There is no doubt that it puts water in motion not astern. It
+twists it up in a rope, so to speak. Its skin frictional resistance is
+very great. In a word, in comparing the hydraulic system with the
+normal system, we are comparing two very imperfect things together;
+but the fact remains, and applies up to a certain point, that the
+hydraulic propeller must be very inefficient, because it, of all
+propellers, drives the smallest quantity of water astern at the
+highest velocity.
+
+There is, moreover, another and a very serious defect in the hydraulic
+propeller as usually made, which is that every ton of water passed
+through it has the velocity of the ship herself suddenly imparted to
+it. That is to say, the ship has to drag water with her. To illustrate
+our meaning, let us suppose that a canal boat passes below a stage or
+platform a mile long, on which are arranged a series of sacks of corn.
+Let it further be supposed that as the canal boat passes along the
+platform, at a speed of say five miles an hour, one sack shall be
+dropped into the boat and another dropped overboard continuously. It
+is evident that each sack, while it remains in the boat, will have a
+speed the same as that of the boat, though it had none before. Work
+consequently is done on each sack, in overcoming its inertia by
+imparting a velocity of five miles an hour to it, and all this work
+must be done by the horse towing on the bank. In like manner the
+hydraulic propeller boat is continually taking in tons of water,
+imparting her own velocity to them, and then throwing them overboard.
+The loss of efficiency from this source may become enormous. So great,
+indeed, is the resistance due to this cause that it precludes the
+notion of anything like high speeds being attained. We do not mean to
+assert that a moderate degree of efficiency may not be got from
+hydraulic propulsion, but it can only be had by making the quantity of
+water sent astern as great as possible and its velocity as small as
+possible. That is to say, very large nozzles must be employed. Again,
+provision will have to be made for sending the water through the
+propeller in such a way that it shall have as little as possible of
+the motion of the ship imparted to it. But as soon as we begin to
+reduce these principles to practice, it will be seen that we get
+something very like a paddle wheel hung in the middle of the boat and
+working through an aperture in her hull, or else a screw propeller put
+into a tube traversing her from stem to stern.
+
+We may sum up by saying that the hydraulic propeller is less efficient
+than the screw, because it does more work on the water and less on the
+boat; and that the boat in turn does more work on the water than does
+one propelled by a screw, because she has to take in thousands of tons
+per hour and impart to them a velocity equal to her own. Part of this
+work is got back again in a way sufficiently obvious, but not all. If
+it were all wasted, the efficiency of the hydraulic propeller would be
+so low that nothing would be heard about it, and we certainly should
+not have written this article.--_The Engineer._
+
+       *       *       *       *       *
+
+
+
+
+THE NEW ARMY GUN.
+
+
+The cut we give is from a photograph taken shortly after the recent
+firings. The carriage upon which it is mounted is the one designed by
+the Department and manufactured by the West Point Foundry, about six
+months since. It was designed as a proof carriage for this gun and
+also for the 10 inch steel gun in course of construction. It is
+adapted to the larger gun by introducing two steel bushing rings
+fitted into the cheeks of carriage to secure the trunnion of the gun.
+
+The gun represented is an 8 inch, all steel, breech-loading rifle,
+manufactured by the West Point Foundry, upon designs from the Army
+Ordnance Bureau. The tube and jacket were obtained from Whitworth, and
+the hoops and the breech mechanism forgings from the Midvale Steel
+Company. The total weight of the gun is 13 tons; total length,
+including breech mechanism, 271 inches; length of bore in front of gas
+check, 30 calibers; powder space in chamber, 3,109 cubic inches;
+charge, 100 pounds. The tube extends back to breech recess from
+muzzle, in one solid piece. The breech block is carried in the jacket,
+the thread cut in the rear portion of the jacket. The jacket extends
+forward and is shrunk over the tube about 871/2 inches. The re-enforce
+is strengthened by two rows of steel hoops; the trunnion hoops form
+one of the outer layers. In front of the jacket a single row of hoops
+is shrunk on the tube and extends toward the muzzle, leaving 91 inches
+of the muzzle end of the tube unhooped. The second row of hoops is
+shrunk on forward of the trunnion hoops for a length of 38 inches to
+strengthen the gun, and the hoop portion forms three conical frustums.
+The elastic resistance of the gun to tangential rupture over the
+powder chamber is computed by Claverino and kindred formulas to be
+54,000 lb. per square inch.
+
+[Illustration: THE ARMY 8 INCH STEEL GUN WITH CARRIAGE.]
+
+The breech mechanism is modeled after the De Bange system. The block
+has three smooth and three threaded sectors, and is locked in place by
+one-sixth of a turn of a block, and secured by the eccentric end of a
+heavy lever, which revolves into a cut made in the rear breech of the
+gun. The gas check consists of a pad made of two steel plates or cups,
+between which is a pad of asbestos and mutton suet formed under heavy
+pressure. The rifling consists of narrow grooves and bands, 45 of
+each. The depth of the groove is six one-hundredths of an inch.
+
+Although the gun is designed for a charge of 100 pounds, it is
+believed that it can be increased to 105 pounds without giving
+dangerous pressure, and the intention is to increase the charge to
+that amount when the new powder is received from Du Pont.
+
+The following is a very full synopsis of the official report of the
+preliminary firings--13 rounds--with this gun:
+
+The first seven rounds were fired with German cocoa powder, which was
+received from Watervliet Arsenal. There were two kinds of cartridges,
+one kind weighing 85 pounds, and having 30 grains in each layer, the
+other weighing 100 lb., and having 27 grains in each layer. In two of
+the first seven rounds the weight of the charge was 65 pounds, the
+projectiles weighing 182 and 286 pounds; in the next two rounds
+charges of 85 pounds were fired, the projectiles, as before, weighing
+182 and 286 pounds, while in the last three of the rounds fired with
+cocoa powder the charge was 100 lb., while the weight of the
+projectile was 182, 235, and 286 pounds. At the seventh round was
+fired the normal charge, 100 lb. of powder and a projectile weighing
+286 pounds, for which the gun was designed. The mean pressure for this
+round, determined by two crusher gauges, was 32,800 pounds, and the
+velocity at 150 feet was 1,787 feet.
+
+Two kinds of Du Pont's brown prismatic powder, marked P.A. and P.I.,
+were then fired. With the normal charge of P.A. powder (round 12 of
+the record), the mean pressure was 35,450 pounds, the velocity at 150
+feet was 1,812 feet. For P.I. powder (round 13 of the record), the
+pressure was 26,925 pounds, the velocity was 1,702 feet, and a
+considerable amount of unconsumed powder was ejected, showing that the
+P.I. powder is not a suitable one for this piece. The highest pressure
+indicated with the normal charge of P.A. powder was 36,200 pounds,
+exceeding by 1,200 pounds the provisional limit of pressure.
+
+At the fifth round the breech block opened with some difficulty, and
+an examination showed that the resistance resulted from the diametral
+enlargement of the rear plate. Directions have been given to correct
+this defect. The star gauge records show that no material change took
+place in the diameter of the chamber or the bore. From 30 inches to 54
+inches (measured from base of the breech), there was a diminution in
+diameter of from 0.001 in. to 0.002 in.; in rear of 30 inches there
+was no change. No enlargement in the shot chamber exceeded 0.001 in.
+From the bottom of the bore (the beginning of the rifling) to the
+muzzle the average enlargements were as follows: in. to 6 in., 0.005
+in.; 7 in. to 14 in., 0.003 in.; 15 in. to 29 in., 0.002 in.; 30 in.
+to muzzle, 0.002 to 0.001 in.
+
+After the third round the joint between the D. and D. rings opened
+slightly on the top, and measured after the 13th round showed that the
+opening was about 0.004 in. wide. It cannot at present be stated
+whether or not this opening increased during firing, but the defect
+has been noted and will be carefully observed. Enough cocoa powder
+remains to allow a comparison to be made with such brown prismatic
+powder as may be adopted finally. No firing has been done as yet to
+test the best position for the bands, but it will take place as soon
+as enough of some standard powder is obtained to fire ten consecutive
+rounds.--_Army and Navy Journal._
+
+       *       *       *       *       *
+
+
+
+
+COMBUSTION, FIRE-BOXES, AND STEAM BOILERS.[1]
+
+  [Footnote 1: Address before the June Convention of the Master
+  Mechanics' Association.]
+
+By JOHN A. COLEMAN.
+
+
+Mr. Chairman and gentlemen: I was rash enough some time ago to promise
+to prepare a paper for this occasion, the fulfillment of which prior
+engagements have absolutely prevented.
+
+I would greatly prefer to be let off altogether, but I do not like to
+break down when expected to do anything; and if you have the patience
+to listen for a few minutes to the reflections of an "outsider," I
+will endeavor to put what I have to say in as concise form as I can,
+in such manner as will do no harm, even if it does no good.
+
+For many years I was connected with steam engineering. I was once with
+the Corliss Steam Engine Company, and afterward was the agent of Mr.
+Joseph Harrison, of Russian fame, for the introduction of his safety
+boilers.
+
+That brought me into contact with the heavy manufacturers throughout
+the Eastern States, and during that long experience I was particularly
+impressed with a peculiarity common to the mill owners, which, I
+believe it may be said with truth, is equally common to those
+interested in locomotive engineering, namely, how much we overlook
+common, every-day facts. For instance, we burn coal; that is, we think
+we do, and boilers are put into mills and upon railroads, and we
+suppose we are burning coal under them, when in reality we are only
+partially doing so. We think that because coal is consumed it
+necessarily is burned, but such is frequently very far from the fact.
+
+I wish upon the present occasion to make merely a sort of general
+statement of what I conceive to be combustion, and what I conceive to
+be a boiler, and then to try to make a useful application of these
+ideas to the locomotive.
+
+Treating first the subject of combustion, let us take the top of the
+grate-bars as our starting point. When we shovel coal upon the grate
+bars and ignite it, what happens first? We separate the two
+constituents of coal, the carbon from the hydrogen. We make a gas
+works. Carbon by itself will burn no more than a stone; neither will
+hydrogen. It requires a given number of equivalents of oxygen to mix
+with so many equivalents of carbon, and a given number of equivalents
+of oxygen to mix with so many of hydrogen to form that union which is
+necessary to produce heat. This requires time, space, and air, and one
+thing more, viz., heat.
+
+I presume that most of you have read Charles Williams' treatise upon
+"Combustion," which was published many years ago, and which until
+recently was often quoted as an absolute authority upon the art of
+burning fuel under boilers. Mr. Williams in his treatise accurately
+describes the chemistry of combustion, but he has misled the world for
+fifty years by an error in reasoning and the failure to discuss a
+certain mechanical fact connected with the combination of gases in the
+process of combustion. He said: "What is the use of heating the air
+put into a furnace? If you take a cubic foot of air, it contains just
+so many atoms of oxygen, neither more nor less. If the air be heated,
+you cause it to assume double its volume, but you have not added a
+single atom of oxygen, and you will require twice the space for its
+passage between the grate bars, and twice the space in the furnace,
+which is a nuisance; but if the air could be frozen, it would be
+condensed, and more atoms of oxygen could be crowded into the cubic
+foot, and the fire would receive a corresponding advantage." Mr.
+Williams proceeded upon this theory, and died without solving the
+perplexing mystery of as frequent failure as success which attended
+his experiments with steamship boilers. The only successes which he
+obtained were misleading, because they were made with boilers so badly
+proportioned for their work that almost any change would produce
+benefit.
+
+Successful combustion requires something more than the necessary
+chemical elements of carbon, hydrogen, and oxygen, for it requires
+something to cook the elements, so to speak, and that is heat, and for
+this reason: When the coal is volatilized in the furnace, what would
+be a cubic foot of gas, if cold, is itself heated and its volume
+increased to double its normal proportion. It is thin and attenuated.
+The cold air which is introduced to the furnace is denser than the
+gas. With dampers wide open in the chimney, and the gases and air
+passing into the flues with a velocity of 40 feet per second, they
+strike the colder surface of the tubes, and are cooled below the point
+of combustion before they have had time to become assimilated; and
+although an opponent in a debate upon steam boiler tests once stated
+that his thermometer in the chimney showed only 250 degrees, and
+indicated that all the value that was practical had been obtained from
+the coal, I took the liberty to maintain that a chemist might have
+analyzed the gases and shown there were dollars in them; and that if
+the thermometer had been removed from the chimney and placed in the
+pile of coal outside the boiler, it would have gone still lower; but
+it would not have proved the value to have been extracted from the
+coal, for it was not the complete test to apply.
+
+The condition of things in the furnace may be illustrated thus: If we
+should mingle a quart of molasses and a gallon of water, it would
+require considerable manipulation and some time to cause them to
+unite. Why? Because one element is so much denser than the other; but
+if we should mix a quart of the gallon of water with the quart of
+molasses, and render their densities somewhere near the density of the
+remaining water, and then pour the masses together, there would be a
+more speedy commingling of the two. And so with the furnace. I have
+always maintained that every furnace should be lined with fire-brick,
+in order that it shall be so intensely hot when the air enters that
+the air shall instantly be heated to the same degree of tenuity as the
+hot gases themselves, and the two will then unite like a flash--and
+that is heat. And here is the solution of the Wye Williams mystery of
+failure when cold air was introduced upon the top of a fire to aid
+combustion. The proof of the necessity for heat to aid the chemical
+assimilation of the volatilized coal elements is seen in starting a
+fire in a common stove. At first there is only a blue flame, in which
+the hand may be held; but wait until the lining becomes white hot, and
+then throw on a little coal, and you will find a totally different
+result. It is also seen in the Siemens gas furnace, with which you are
+doubtless familiar. There is the introduction of gas with its
+necessary complement of air. Until the furnace and retorts become
+heated, the air and gas flutter through only partially united, and do
+little good; but as soon as the retorts and furnace become thoroughly
+hot, the same gas and air will melt a fire-brick.
+
+These are common phenomena, which are familiar, but apt to be
+unnoticed; but they logically point to the truth that no furnaces
+should present a cooling medium in contact with fuel which is
+undergoing this process of digestion, so to speak. It will be very
+evident, I think, from these facts that water-legs in direct contact
+with a fire are a mistake. They tend to check a fire as far as their
+influence extends, as a thin sheet of ice upon the stomach after
+dinner would check digestion, and for the same reason, namely, the
+abstraction of heat from a chemical process. If fire-brick could be
+laid around a locomotive furnace, and the grate, of course, kept of
+the same area as before, it is my belief that a very important
+advantage would be at once apparent. An old-fashioned cast iron heater
+always produced a treacherous fire. It would grow dead around the
+outside next to the cold iron; but put a fire-clay lining into it, and
+it was as good as any other stove.
+
+If I have now made clear what I mean by making heat, we will next
+consider the steam boiler. What is a steam boiler? It is a thing to
+absorb heat. The bottom line of this science is the bottom of a pot
+over a fire, which is the best boiler surface in the world; there is
+water upon one side of a piece of iron and heat against the other. One
+square foot of the iron will transmit through it a given number of
+units of heat into the water at a given temperature in a given time;
+two square feet twice as many, and three, three times as many, and so
+on. Put a cover upon the pot, and seal it tight, leave an orifice for
+the steam, and that is a steam boiler with all its mysteries.
+
+The old-fashioned, plain cylinder boiler is a plain cylindrical pot
+over the fire. If enough plain cylinder boilers presenting the
+requisite number of square feet of absorbing surface are put into a
+cotton mill, experience has shown that they will make a yard of cotton
+cloth about as cheaply as tubular boilers. If this is so, why do not
+all put them in? Because it is the crudest and most expensive form of
+boiler when its enormous area of ground, brickwork, and its fittings
+are considered. Not all have the money or the room for them. To
+produce space, the area is drawn in sidewise and lengthwise, but we
+must have the necessary amount of square feet of absorbing surface,
+consequently the boiler is doubled up, so to speak, and we have a
+"flue boiler." We draw in sidewise and lengthwise once more and double
+up the surface again, and that is a "tubular boiler." That includes
+all the "mystery" on that subject.
+
+Now, we find among the mills, just as I imagine we should upon the
+railroads, that the almost universal tendency is to put in too small
+boilers and furnaces. To skimp at boilers is to spend at the coal
+yard. Small boilers mean heavy and over-deep fires, and rapid
+destruction of apparatus. In sugar houses you will see this frequently
+illustrated, and will find 16 inch fires upon their grates.
+
+We have found that, as we could persuade mill owners to put in more
+boilers and extend their furnaces, so that coal could be burned
+moderately and time for combustion afforded, we often saved as high as
+1,000 tons in a yearly consumption of 4,000.
+
+Now, when the ordinary locomotive sends particles of coal into the
+cars in which I am riding, I do not think it would be unfair criticism
+to say that the process of combustion was not properly carried out.
+When we see dense volumes of gas emitted from the stack, it is evident
+that a portion of the hard dollars which were paid for the coal are
+being uselessly thrown into the air; and it will be well to remember
+that only a little of the unburnt gas is visible to the eye.
+
+One point I wish to make is this: We find, as I have said, that as we
+spread out with boilers and furnaces in the mills, so that we can take
+matters deliberately, we save money.
+
+Now, coming again to locomotives. I think, if we examine the subject
+carefully, the fact will strike us a little curiously. The first
+locomotive built in Philadelphia weighed about 14 tons. Judging from
+the cut I have seen, I should think her furnace might have been 30
+inches square. We have gone from that little 14 ton engine to machines
+of 50 and 60 tons--perhaps more. The engines have been increased over
+four times, but I will ask you if the furnace areas have been
+increased (applause) in proportion? Some of the furnaces of the
+engines are six feet by three, but that is an increase of less than 3
+to 1 of furnace, as against 4 to 1 of weight of engine.
+
+When my attention was first called to this matter, I had supposed, as
+most people do who are outside of the railway profession, that there
+was something subtile and mysterious about railway engineering that
+none but those brought up to the business could understand. Possibly
+it is so, and I am merely making suggestions for what they are worth,
+but I think the position I have taken in this matter was established
+by some experiments of three weeks' duration, which I conducted
+between Milan and Como, in Italy, for the Italian government, in
+pulling freight trains up grades of 100 feet to the mile. The
+experiments were made with an engine built by the Reading Railroad.
+
+We competed with English, French, Belgian, and Austrian engines. These
+machines required the best of fuel to perform the mountain service,
+and could use coal dust only when it was pressed into brick. We used
+in the Reading Railroad machine different fuels upon different days,
+making the road trip of 120 miles each day with one kind of fuel. We
+used coal dust scraped up in the yards, also the best Cardiff coal,
+anthracite, and five kinds of Italian lignite, the best of which
+possesses about half the combustible value of coal.
+
+The results in drawing heavy freight trains were equally good with
+each fuel, the engine having at all times an abundance of steam on
+heavy grades, no smoke nor cinders, and no collection of cinders in
+the forward part of the engine.
+
+The fireman arranged his fires at a station, and did little or nothing
+except to smoke his pipe and enjoy the scenery until he reached the
+next station. An incident occurred to prove that we were not playing
+with the machine. They told me one morning that we should be given a
+load of 25 per cent less than the maximum load of an engine of her
+class (30 tons). We started up the 100 foot grade, and found we could
+barely crawl, and our engineer got furious over it. He thought they
+were repeating a trick already attempted by screwing down a brake in
+ascending a grade. We detected it, however, and found a pair of wheels
+nearly red hot. Upon this occasion we found nothing amiss, except full
+cars where they had reported only a light load. We pulled to the top
+of the hill, the steam blowing off furiously all the time.
+
+This was a new experience to the Italians, and might surprise some
+Americans. When we arrived at the station, the inspector-general and
+his corps of engineers were evidently amazed, and it was evident we
+had captured them. He said to me, "I can congratulate you, signor, on
+possession of a superb machine."
+
+Afterward one of the engineers said to me: "Do not let it be known
+that I told you what you have hauled or I shall lose my place, but you
+have drawn 50 per cent more than the maximum load of one of our 40 ton
+engines." I said: "You attempted to 'stall' us, and when you try it
+again, be fair enough to give me a flat of pig iron, and as you pack
+cars on one end I will pack pig iron upon the engine until she will
+stick to the track, but rest assured that you will not be able to get
+that steam down." The experience with that engine proves conclusively
+to my mind that the general principles of steam making are the same
+for both stationary and locomotive practice. The grand secret of the
+success of that Wootten engine was the enormous area of the grate
+surface, being, if I remember correctly, 7 by 9 feet, permitting thin
+fires to be carried and complete combustion to be obtained before the
+gases reached the boiler tubes. An enormous crown sheet was presented,
+and that is where the bulk of the work of any boiler is done.
+
+Thin fires accomplish this. As already stated, a given amount of coal
+generates a given amount of gas, and this gas requires a given amount
+of air or oxygen. This air must be supplied through the grate bars and
+then pass through the interstices of the mass of heated coal. It
+requires about 10 cubic feet of air to consume one cubic foot of gas.
+In stationary boilers we find that if we use "pea" and "dust" coal, an
+extremely thin layer must be used, or the 10 feet of air per foot of
+gas cannot pass through it; if "chestnut" coal be used, the thickness
+may be increased somewhat; "stove size" allows a thickness of six
+inches, and "lump" much thicker, if any wise man could be found who
+would use that coarse, uneconomical size. Of course, I am speaking of
+anthracite coal. Opinions differ about "soft coal," but the same
+general principle applies as regards an unobstructed passage of air
+through the hot bed of coal.
+
+Now, it will be agreed that the locomotive of the future must be
+improved to keep up with the times. Fierce competition requires
+increased efficiency and reduced expenses. I am told by you railroad
+gentlemen that the freight business of the country doubles every ten
+years. Trains follow close upon each other. What are you going to do?
+Are you to double, treble, or quadruple your tracks?
+
+It seems to me much remains yet to be done with the locomotive. We
+must burn a great deal less coal for the steam we make, and after we
+have made steam we must use that steam up more thoroughly. In the
+short cylinder required by locomotive service, the steam, entering at
+the initial pressure pushes the piston to the opposite end, and it
+then rushes out of the exhaust strong enough to drive another piston.
+Of every four dollars' worth of coal consumed, at least two dollars
+worth is absolutely thrown away. Or, of every ten thousand dollars
+spent for fuel, five thousand dollars are absolutely wasted. How can
+we save this? It would seem obvious that if steam rushes from the
+exhaust of an engine strong enough to drive another engine, the common
+sense of the thing would be to put another engine alongside and let
+the steam drive it, and we should get just so much more out of our
+four dollars' worth of coal. It seems evident that we must follow the
+lead of the steamship men, and compound the locomotive engine, as
+they have done with the marine engine.
+
+Next we must attack the extravagant furnace, and increase its area and
+reduce the depth of the bed of coal. The difficulty of making this
+change seemed to me to be removed, on examining an engine on the
+Providence & Bristol Railroad, the other day. The machine was made at
+the Mason Works, of Taunton. It was an engine and tender combined, the
+truck being at the rear end of the tender, and the driver placed well
+in advance of the fire-box, so that the maximum weight of both engine
+and tender rested upon the drivers. In thus removing the drivers from
+the proximity of the fire-box, abundant facility is afforded for
+widening the fire-box, so as to obtain a grate area as large as that
+of the Wootten engine or of a stationary boiler. It seems to me the
+increase of grate area can be obtained only by widening; for a length
+of more than six or seven feet is very hard upon the fireman. You
+certainly cannot get more power by deepening present fire-boxes,
+except by an enormously increased waste of fuel, which all will
+concede is already sufficiently extravagant.
+
+In arriving at the conclusion of these hasty and I fear somewhat
+incoherent remarks, I would say that the object aimed at for the
+improvement of the locomotive would be reached, first, by making steam
+economically, by employing such increased grate area as will permit
+running thin fires and moderate or comparatively slow draught; and,
+secondly, in economically using the steam which has been economically
+made by compounding the engine.
+
+I have given you merely the views of an "outsider," who has had a
+somewhat extensive experience in stationary engineering, and who has
+observed locomotive practice in many parts of the world. These views
+are offered for what they are worth, as suggestions for future thought
+in designing engines, and as a sort of refresher upon rudimentary
+points which long familiarity with every-day phenomena causes us at
+times to overlook. I trust that your deliberations may aid in the
+speedy reduction of the expenses of transporting freight and
+passengers, for the benefit of the railroad companies and, in their
+turn, the advantage of the people at large.
+
+       *       *       *       *       *
+
+
+
+
+ATLANTIC STEAMERS.[1]
+
+  [Footnote 1: A paper recently read before the Institution of Naval
+  Architects.]
+
+By W. JOHN.
+
+
+[Illustration: Fig. 1--CITY OF ROME.]
+
+The author said that he hoped to bring before the meeting impartially
+certain facts which might be of interest, and which, when recorded in
+the pages of the "Transactions," might be found of some use as data
+for future reference. In dealing with passenger steamers, he would do
+so principally from a shipbuilder's point of view; but the moment he
+commenced to think over Atlantic passenger ships as a shipbuilder, he
+was met by the question whether the present tendency toward divorcing
+the passenger and cargo trade from each other is likely to continue or
+not. If the answer is yes, then it seems to become an important
+question, for the present at least, how to build, on moderately small
+dimensions, the fastest, safest, and most economical passenger
+steamer, using all the most modern improvements to make her commodious
+and luxurious, and an easy sea boat into the bargain. If cargo is
+still to be carried in the passenger ships of the future, a moderate
+speed only will be aimed at in the immediate future, and every effort
+will be devoted to economy of fuel, comfort, and safety, with a fair
+carrying capacity. This latter policy is one which may possibly
+prevail at least for a time, as it has powerful supporters in
+Liverpool; but he could not help thinking that very high
+speeds--higher than we have yet attained--must eventually gain the
+day. He also thought that they were on the eve of important movements,
+which will indicate what the next step in the passenger trade is to
+be; for it must be remembered, among other things, that none of our
+present English transatlantic liners, even the latest, have yet been
+fitted with the latest modern improvements for economy of fuel or
+quick combustion, such as triple expansion engines or forced draught.
+They must, therefore, be at some disadvantage, other things being
+equal, compared with the ships of the future possessing them. The
+Great Eastern steaming up Milford Haven about twenty-five years ago
+between two lines of the channel fleet of old--two and three decked
+wooden line-of-battle ships--the whole fleet saluting with yards
+manned, was a sight to be remembered. More than this, that ship, with
+all her mournful career, has been a useful lesson and a useful warning
+to all naval architects who seriously study their profession--a lesson
+of what can be done in the safe construction of huge floating
+structures, and a warning that the highest flights of constructive
+genius may prove abortive if not strictly subordinated to the
+practical conditions and commercial requirements of the times. The
+Sirius and Great Western crossed the Atlantic in 1838, and in 1840 the
+first ship of the since celebrated Cunard Company made her first
+voyage. This was the Britannia, which, with her sister ships, the
+Arcadia, Caledonia, and Columbia, kept up the mail service regularly
+at a speed of about 81/2 knots an hour. The Britannia was 207 ft. in
+length between perpendiculars, and 34 ft. 4 in. extreme breadth, 22
+ft. 6 in. depth of hold, 423 horse power--nominal--and 1,153 tons
+burden, built of wood, and propelled by paddles. In 1860 the Collins
+Line started in opposition to the Cunard, and, after a series of
+disasters, collapsed in 1858. This was three years after the Persia,
+the first Cunarder built of iron, had been completed. In 1850, also,
+the Inman Line was started with the City of Glasgow, of 1,600 tons
+builders' measurement, and 350 horse power. She was built of iron, and
+was the first screw steamer sent across the Atlantic from Liverpool
+with passengers, and was the pioneer of the great emigrant trade which
+Mr. Inman, above all others, did so much to develop and make cheap and
+comfortable for the emigrants themselves, as well as profitable to his
+company. That the builders of the celebrated old Great Britain, in
+1843, and Mr. Inman, in 1850, should have pronounced so decisively in
+favor of the screw propeller in preference to the paddle for ocean
+steaming is a proof of their true practical judgment, which time and
+practical experience have made abundantly clear. While the Cunard
+Company went on developing its fleet from the early wood paddle
+steamer Britannia of 1,130 tons in 1840 to the iron paddle steamers
+Persia, etc., in 1858, the iron screw steamer China of 1862, to the
+still more important screw steamers Bothnia and Scythia, vessels of
+4,335 tons, in 1874, the Inman and other lines were as rapidly
+developing in speed and size, if not in numbers. The year 1874 is
+memorable, for it saw the White Star steamers Britannic and Germanic
+put into the water, as well as the Inman steamer City of Berlin and
+the two before mentioned Cunard steamers, Bothnia and Scythia. By the
+addition of these two ships to their fleet the White Star Line,
+although started only in 1870, reached a front rank position in the
+New York passenger trade. The author gave in separate tables the logs
+of several of these ships, some from published documents and some
+kindly furnished by the owners. The Great Western had crossed the
+Atlantic from Bristol to New York in 15 days as early as 1838. The
+first Cunard steamer, the Britannic, was about the same speed, from 81/4
+to 81/2 knots an hour. The average duration of the Cunard voyages in the
+year 1856 was 12.67 days from Liverpool to New York, and 11.03 days
+from New York to Liverpool. The Bothnia, in 1874, reduced the passage
+to about nine days. The White Star Britannic, in 1876, averaged 7 days
+18 hours 26 minutes outward from Queenstown to New York, and 9 days 6
+hours 44 minutes homeward, and has averaged for the last ten years 8
+days 9 hours 36 minutes outward, and 8 days 1 hour 48 minutes
+homeward. The City of Berlin, of the Inman Line, also built in 1874, 8
+days 10 hours 56 minutes, and homeward 8 days 2 hours 37 minutes; and
+for the nine years from 1875 to 1883 inclusive, averaged outward 8
+days 19 hours 56 seconds, and inward 8 days 8 hours 34 seconds; or,
+putting it into rounder figures, the Britannic had reduced the average
+passage between the two points to 81/4 days, and the City of Berlin to
+81/2 days. From the year 1874 on to 1879 no further advance was made in
+Atlantic steaming, but in that year the Arizona was added to the Guion
+Line, and it soon became evident that another important stride had
+been made in the Atlantic passenger trade, which would lead to most
+important results. The results, as we all know, have been sufficiently
+startling. The Guion Line, which had started in 1866 with the
+Manhattan, had now the fastest passenger ship on the Atlantic. In
+spite of burning some fifty per cent. more coal than the Britannic,
+the ship was an obvious commercial success. The spirited policy which
+brought her into existence was appreciated by the public, and the
+other lines had to move forward. Then followed a period of rivalry,
+the Cunard Company building the Gallia and Servia, the Inman Company
+the City of Rome, and the Guion Line the Alaska, all of which were
+completed in 1881, and afterward the Oregon for the Guion
+Line--1883--the Aurania the same year for the Cunard Company, and,
+later still, the America for the National Line, and the Umbria and
+Etruria for the Cunard Company in 1885.
+
+[Illustration:
+
+_Frames from outer edge of Tank to Upper Deck, 7 x 31/2 x 8/16 for 250
+ft. Amidships, for 60 ft. before and abaft these Points 61/2 x 31/2 x 6/16
+at end of Vessel 5 x 31/2 x 7/16, all spaced 24 in. apart and all
+carried to Upper Deck, double from Bilge to Bilge in way of
+Engines.--Frames in Tank on Lattice and Solid Floors, 5 x 31/2 x 8/16,
+Intermediate Frames, 8 x 4 x 9/16--Rev: Frames, 41/2 x 31/2 x 8/16,
+carried to Upper and Main Deck alternately double, 41/2 x 41/2 x 8/16 from
+Bilge to Bilge in E and B space._
+
+Fig. 2--SERVIA.]
+
+Since the completion of the Etruria, for various reasons there has
+been a pause in the tremendous strides made since 1879, and we may
+briefly review the results. Taking the Britannic as a standard with
+her ten years' average of 81/4 days across, and her quickest passage of
+7 days 10 hours 53 seconds, we have now the following steamers of
+higher speeds. Taking them in the order of their absolutely fastest
+passage out or home, they stand thus:
+
+
+TABLE I.
+
+  ---+-------------------------+------+-------+------
+     |                         | Days.| Hours.| Mins.
+     |                         +------+-------+------
+   1 | Etruria.                |   6  |   5   |  31
+   2 | Umbria (sister ship).   |   slightly longer.
+   3 | Oregon.                 |   6  |  10   |  35
+   4 | America.                |   6  |  13   |  44
+   5 | City of Rome.           |   6  |  18   |   0
+   6 | Alaska.                 |   6  |  18   |  37
+   7 | Servia.                 |   6  |  23   |  55
+   8 | Aurania.                |   7  |   1   |   1
+  ---+-------------------------+------+-------+------
+
+It will thus be seen that from the 15 days' passage or thereabout, of
+the earliest Atlantic steamers, we had got down in the days of the
+Scotia to about 9 days; in the Britannic to 81/4 days, and, at the
+present time, we have got to 61/4 days, with seven ships afloat that
+have done the passage under seven days, and capable of making their
+average passages range between 61/2 and 71/4 days.
+
+Ranged in order of gross tonnage, these eight vessels stand as
+follows:
+
+
+TABLE II.
+
+  1. City of Rome.    8,144
+  2. Oregon.          7,375
+  3. Aurania.         7,269
+  4. Servia.          7,212
+  5. Umbria.          7,129
+  6. Etruria.         7,100
+  7. Alaska.          6,586
+  8. America.         5,528
+
+Here the America shows to advantage, for while being eighth in size
+she is fourth in point of speed, and from what the author can learn,
+although he had no authenticated details on the subject, he believed
+she is economical in coal consumption. He might perhaps be permitted
+to say that one of the most difficult subjects in connection with the
+propulsion of ships on which to get absolutely accurate data is that
+of coal consumption. The records of six to eight hours' trials for the
+purpose of ascertaining the coal consumption are absolutely worthless,
+as all shipbuilders and engineers know, and so far as English ships
+are concerned they are never attempted. Foreign owners frequently
+stipulate for such trials in their contracts with English
+shipbuilders, and get wonderfully economical results on paper, but the
+fact that the trials only extend over a few hours renders them
+valueless, however carefully the coal may be weighed during that
+period. An authentic record of the absolute quantity of coal consumed,
+say by each of the eight fastest Atlantic liners, together with their
+average indicated horse power on the voyage, for a series of voyages,
+would be extremely valuable.
+
+He gave, in Table III., the consumption per indicated horse power per
+hour for a number of ships. This table affords valuable data, for it
+gives, in addition to the dimensions, the moulded draught of water,
+the midship area, the displacement, the indicated horse power, the
+speed on trial, the coefficients for the lines both from the block or
+parallelopipedon, and also from the midship section prism, together
+with the length and angle of entrance obtained by Kirk's rule, the
+Admiralty displacement coefficient, together with the coal consumption
+per day and per indicated horse power per hour.
+
+[Illustration: Fig. 3--OREGON.]
+
+This table, as will be seen, contains some of the most important of
+the Atlantic liners, and also a number of other typical ships, which
+will add a variety to its interest and a value to it. The coefficient,
+which is contained in the thirteenth column of the table, viz.:
+
+        Dis 2/3 x speed cubed
+    -------------------------
+    I.H.P. x sqrt(entrance.)
+             ---------------
+                     10
+
+generally comes out for ships of similar type more nearly a constant
+in the true sense of the word than the corresponding Admiralty
+constant. As an example, we have the curves of resistance and horse
+power for the City of Rome and the Normandie, a large vessel of 6,000
+tons, which the Barrow Company built for the Compagnie Generale
+Transatlantique, in which the coefficient of fineness and the form of
+the lines pretty closely resemble each other below water; and if we
+take from the curves the corresponding speeds and horse powers, and
+work out the constants by the two systems, we have at 14 knots the
+Admiralty constant for the City of Rome 322.2, and for the Normandie
+304.8; and taking for a modified form of constant, the City of Rome
+gives 253.7 and the Normandie 251.9, which, as will be seen, are much
+closer together. Similarly, at 15 knots the Admiralty constant for the
+City of Rome is 310, and for the Normandie 295.2, while a modified
+constant comes out for the former at 245, and for the latter 244,
+again agreeing almost identically. The same at 16 knots, for the City
+of Rome the Admiralty constant comes out 297.6, and for the Normandie
+282.8, while a modified constant comes out for the two ships 234.4 and
+233.7 respectively, again showing marked agreement. It may be
+mentioned that in these two ships the engines are of a similar type,
+being three-crank tandem engines, and the propellers have in both
+pitch and surface practically the same proportions to the power and
+speed. The value of these modified constants will probably be found to
+increase as the speeds increase up to the limit and beyond that point
+at which wave resistance becomes an important factor.
+
+
+TABLE III
+
+----------------+--------+---------+---------+-------+-------------+
+    Name.       |Length. | Breadth.| Moulded |Midship|Displacement.|
+                |        |         | draught.| area. |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+----------------+--------+---------+---------+-------+-------------+
+                |ft. in. | ft. in. | ft. in. |       |             |
+                |        |         |         |       |             |
+City of Rome    | 542  6 | 52   0  | 21  51/2  | 1031  |   11,230    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Normandie       | 459  4 | 49  11  | 19  93/4  |  892  |    7,975    |
+                |        |         |         |       |             |
+Furnessia       | 445  0 | 44   6  | 22  21/2  |  893  |    8,578    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Arizona         | 450  0 | 45   11/2 | 18  9   |  758  |    6,415    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Orient          | 445  0 | 46   0  | 21  41/2  |  904  |    7,770    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Stirling Castle | 420  0 | 50   0  | 22  3   |  990  |    7,600    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Elbe            | 420  0 | 44   9  | 20  0   |  807  |    6,350    |
+                |        |         |         |       |             |
+Pembroke Castle | 400  0 | 42   0  | 17  0   |  648  |    5,130    |
+                |        |         |         |       |             |
+Umbria and      |        |         |         |       |             |
+ Etruria        | 500  0 | 57   0  | 22  6   | 1090  |    9,860    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Aurania         | 470  0 | 57   0  | 20  0   | 1020  |    8,800    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+America         | 441  8 | 51   3  | -----   |  ---  |    6,500    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Oregon          | 501  0 | 54   2  | 23  8   | 1150  |   11,000    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Servia          | 515  0 | 52   0  | 23  31/2  | 1046  |   10,960    |
+                |        |         |         |       |             |
+Scotia, P.S.    | 369  0 | 47   6  | 19  9   |  867  |    6,000    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Alaska          | 500  0 | 50   0  | 21  0   |  949  |    9,210    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Aller           | 438  0 | 48   0  | 21  0   |  907  |    7,447    |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+                |        |         |         |       |             |
+Ems             | 430  0 | 46  10  | 20  71/2  |  877  |    7,030    |
+----------------+--------+---------+---------+-------+-------------+
+
+----------------+----------+---------+-----------+-----------+-----------+
+    Name        |Indicated |  Speed. |   Block   |  Midship  | Prismatic |
+                |   H.P.   |         |coefficient|  section  |  midship  |
+                |          |         |           |coefficient|  section  |
+                |          |         |           |           |coefficient|
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+----------------+----------+---------+-----------+-----------+-----------+
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+City of Rome    | 11,890   |  18.235 |    .649   |    .925   |    .702   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Normandie       |  6,959   |  16.66  |    .614   |    .901   |    .681   |
+                |          |         |           |           |           |
+Furnessia       |  4,045   | ¹14     |    .682   |    .903   |    .755   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Arizona         |  6,300   |  17     |    .589   |    .895   |    .658   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Orient          |  5,433   |  15.538 |    .621   |    .919   |    .676   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Stirling Castle |  8,396   |  18.4   |    .569   |    .889   |    .639   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Elbe            |  5,665   |  16.571 |    .591   |    .901   |    .655   |
+                |          |         |           |           |           |
+Pembroke Castle |  2,435.8 |  13.25  |    .623   |    .623   |    .692   |
+                |          |         |           |           |           |
+Umbria and      |          |         |           |           |           |
+ Etruria        | 14,321   |  20.18  |    .538   |    .896   |    .637   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Aurania         |  8,500   | ¹17.5   |    .575   |    .942   |    .632   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+America         |  -----   | ¹17.8   |    ----   |    ----   |    ----   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Oregon          | 13,300   |  18.3   |    .599   |    .849   |    .67    |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Servia          | 10,300   | ¹16.9   |    .610   |    .862   |    .71    |
+                |          |         |           |           |           |
+Scotia, P.S.    |  4,632   | ¹14.31  |    .605   |    .92    |    .65    |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Alaska          |  -----   |  ----   |    .614   |    .904   |    .679   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Aller           |  7,974   |  17.9   |    .590   |    .899   |    .656   |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+                |          |         |           |           |           |
+Ems             |  7,251   |  17.55  |    .593   |    .907   |    .652   |
+----------------+----------+---------+-----------+-----------+-----------+
+
+----------------+------------+-----------------+-----------------+
+    Name.       | D 2/3 x S cubed |    D 2/3 x S cubed   | Kirk's system.  |
+                | ---------- | --------------- |                 |
+                |   I.H.P.   |           _____ +---------+-------+
+                |            |I.H.P. x \/ent.  |Length of|Angle. |
+                |            |         ------- |entrance.|       |
+                |            |            10   |         |       |
+----------------+------------+-----------------+---------+-------+
+                |            |                 |         |       |
+                |            |                 |         |       |
+City of Rome    |    255     |     201.3       |  161.27 | 8 deg. 29'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Normandie       |    265     |     219.5       |  146.41 | 8 deg. 44'|
+                |            |                 |         |       |
+Furnessia       |    284     |     273         |  108.7  |10 deg. 28'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Arizona         |    269.2   |     217         |  153.79 | 7 deg. 30'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Orient          |    270.8   |     225         |  144.17 | 8 deg. 21'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Stirling Castle |    286.8   |     233.7       |  151.3  | 8 deg. 22'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Elbe            |    275.5   |     229         |  144.6  | 7 deg. 56'|
+                |            |                 |         |       |
+Pembroke Castle |    284     |     258         |  122.9  | 8 deg. 49'|
+                |            |                 |         |       |
+Umbria and      |            |                 |         |       |
+ Etruria        |    260     |     191.8       |  184    | 6 deg. 52'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Aurania         |    266     |     204.6       |  170    | 8 deg. 38'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+America         |    ---     |     ---         |   ---   | ----- |
+                |            |                 |         |       |
+                |            |                 |         |       |
+Oregon          |    227.9   |     190         |  164.3  | 9 deg. 39'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Servia          |    231     |     192         |  145.3  |10 deg. 42'|
+                |            |                 |         |       |
+Scotia, P.S.    |    208.9   |     186         |  126.8  |13 deg. 21'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Alaska          |    ---     |     ---         |  160.23 | 8 deg.  2'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+Aller           |    277     |     225         |  150.6  | 8 deg. 10'|
+                |            |                 |         |       |
+                |            |                 |         |       |
+                |            |                 |         |       |
+Ems             |    273     |     223         |  149.4  | 8 deg. 40'|
+----------------+------------+-----------------+---------+-------+
+
+----------------+------------+--------------------+----------------+--------+
+    Name.       |   Coal     |      Cylinders     |     Boilers    | Working|
+                |consumption |                    |                |Pressure|
+                |-----+------+-------------+------+--------+-------+        |
+                | Per | Per  |  Diameter   |Stroke|Heating |  Bar  |        |
+                | day |I.H.P.|             |      |surface |surface|        |
+                |     |      |             |      |        |       |        |
+----------------+-----+------+-------------+------+--------+-------+--------+
+                |     |      |    Ins.     | Ins. |        |       | lbs.   |
+                |     |      |/3 @  46    \|      |        |       |        |
+City of Rome    | 185 |  2.2 |\3 @  86    /|  72  | 29,286 |  1398 |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/3 @ 35-7/16\|      |        |       |        |
+Normandie       | 148 |  2   |\3 @ 74-7/8 /|  67  | 21,404 |   756 |   85.2 |
+                |     |      |             |      |        |       |        |
+Furnessia       |  97 |  2.2 |  49-100     |  66  | 10,396 |   440 |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Arizona         | --- |  --- |\2 @  90    /|  66  |  ----  |  ---- |   90   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  60    \|      |        |       |        |
+Orient          | --- |  --- |\2 @  85    /|  60  |  ----  |  ---- |   75   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Stirling Castle | --- |  --- |\2 @  90    /|  66  | 21,161 |   787 |  100   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  60    \|      |        |       |        |
+Elbe            | --- |  --- |\2 @  85    /|  60  |  ----  |  ---- |  ---   |
+                |     |      |             |      |        |       |        |
+Pembroke Castle |  44 |  1.7 | 43 and 86   |  57  |  7,896 |   288 |   99   |
+                |     |      |             |      |        |       |        |
+Umbria and      |     |      |/1 @  71    \|      |        |       |        |
+ Etruria        | 315 |  2.1 |\2 @ 105    /|  72  | 38,817 |  1606 |  110   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  68    \|      |        |       |        |
+Aurania         | 215 |  2.2 |\2 @  91    /|  72  | 23,284 |  1001 |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  63    \|      |        |       |        |
+America         | 185 |  --- |\2 @  91    /|  66  |  ----  |   882 |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  70    \|      |        |       |        |
+Oregon          | 310 |  2.2 |\2 @ 104    /|  72  | 38,047 |  1428 |  110   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  72    \|      |        |       |        |
+Servia          | 205 |   2  |\2 @ 100    /|  78  | 27,483 |  1014 |  ---   |
+                |     |      |             |      |        |       |        |
+Scotia, P.S.    | 168 |  3.4 |             |  --  |  ----  |  ---- |  ---   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  68    \|      |        |       |        |
+Alaska          | --- |  --- |\2 @ 100    /|  72  |  ----  |  ---- |  100   |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  44    \|      |        |       |        |
+Aller           | --- |  --- ||1 @  70    ||  72  | 22,630 |   799 |  150   |
+                |     |      |\1 @ 100    /|      |        |       |        |
+                |     |      |             |      |        |       |        |
+                |     |      |/1 @  62    \|      |        |       |        |
+Ems             | --- |  --- |\2 @  86    /|  60  | 19,700 |   780 |  100   |
+----------------+-----+------+-------------+------+--------+-------+--------+
+
+  ¹Mean speed of a voyage across the Atlantic Ocean.
+
+The author next considered the strains to which a ship is exposed, and
+stated that he had before him the calculations for three of the
+largest vessels, two of them of iron and the other of steel; and he
+found, in the case of the iron, the maximum tension on the gunwale
+during the greatest hogging strains likely to be endured at sea would
+not exceed about six tons per square inch, while in the case of the
+steel ship it is only about 61/2 tons. These strains are well within the
+limits of safety, and a comparison of the scantlings of these with the
+others justifies the assertion as to their general safety from a
+structural point of view. The sections of these three ships are shown
+in Figs. 1, 2, and 3, with their principal scantlings. It will be seen
+from these sections that the three ships differ materially in their
+mode of construction. In the case of Fig. 1, which represents the City
+of Rome, the largest of the three, it will be seen that the main
+framing of the vessel is entirely transverse, with very heavy keelsons
+in the bottom, and large partial bulkheads or web frames, and the
+outside plating arranged on what is termed the edge to edge principle,
+with a great portion of it double. In the next section, Fig. 2, the
+Servia, which is built of steel, on the other hand, the bottom is
+built on the longitudinal cellular system, the first application, he
+believed, of this system to an Atlantic liner. The plating of the
+Servia is of the usual alternate outer and inner strake system, partly
+double; while the third section, the Oregon, approaches more nearly to
+the ordinary system of framing and plating usually adopted, but it
+will be seen that she was well tied in the bottom by very heavy
+intercostal and plate keelsons, as well as in the top by heavy
+stringers and sheer strakes, with much of her plating doubled, and
+heavy web frames inside. The author next considered the question of
+stability, and went on to deal with the subject of twin screws, and
+stated that the Barrow Shipbuilding Company has done more in the way
+of planning and designing for the adoption of twin screws lately than
+for any other mode of propulsion, and this chiefly for passenger
+steamers. He did not attach much importance to the particular form of
+the blade either in single or twin screws, as he believed so long as
+the disk area, the surface, and pitch were properly adjusted to the
+speed of the vessel, and to enable the engines to use, at the maximum
+speed, just the full quantity of steam that the boilers can make, we
+have got pretty nearly as far as we can get. To fix these dimensions
+of the propeller accurately at the present time, and without further
+knowledge of the action of the screw on the water, was, he thought,
+impossible. All the rules and formulae are empirical. The best one he
+knew is given in Table IV., due to Mr. Thom, the head of the Barrow
+Company's engineering drawing office, and at present acting manager,
+who has used it for some years in practice. These formulae are based
+upon the assumption that the area of propeller disk should be
+proportional to the indicated horse power, divided by the cube of the
+speed, and the same with the projected area of the propeller and also
+the surface.
+
+
+TABLE IV.
+
+             _Particulars of Propellers and Constants._
+
+------------------------------+-------+---------+----------+--------------
+                              | Length|         |   Proj.  |  Feet per
+            Ship.             |   of  |  Disk   |   surf.  |   minute.
+                              | ship. |constant.| constant.|Speed of tips.
+------------------------------+-------+---------+----------+--------------
+City of Rome.                 |   542 |   220   |    69    |   4,715
+Normandie                     |   459 |   250   |    66    |   4,099
+Furnessia                     |   445 |   223   |    69    |   3,654
+Eden                          |   300 |   211   |    64    |   3,080
+Yorouba                       |   270 |   213   |    63    |   3,202
+Taygete                       |   260 |   238   |    56    |   3,166
+Kow-shing                     |   250 |   171   |    69    |   3,369
+S.Y. Monarch                  |   152 |   221   |    65    |   4,040
+S.Y. Aries                    |   138 |   179   |    56    |   2,986
+Twin screw Fenella            |   200 |   244   |    64    |   2,890
+Twin screw H.M.S. Fearless[2] |   220 |   277   |    67    |   5,022
+Twin screw H.M.S. Iris        |   --- |   454[6]|   135[6] |    ---
+Twin screw H.M.S. Iris [3]    |   300 |   412   |   221    |    ---
+Twin screw H.M.S. Iris [4]    |   300 |   346   |    99    |   4,961
+Twin screw H.M.S. Iris [5]    |   300 |   439   |    82    |   5,309
+------------------------------+-------+---------+----------+-------------
+
+  [Footnote 2: Estimated with a speed of 17.5 knots and 3,370
+  I.H.P.]
+
+  [Footnote 3: With the first propeller at the estimated speed of
+  17.5 knots and 7,000 I.H.P.]
+
+  [Footnote 4: With four bladed modified Griffith's on actual
+  trial.]
+
+  [Footnote 5: With two bladed modified Griffith's on actual trial.]
+
+  [Footnote 6: Constants obtained from first propeller calculated
+  from a speed of 18.5 knots and 7,500 I.H.P.
+
+                    Area of propeller disk x speed of ship in knots. cubed
+    Disk constant = --------------------------------------------------
+                                         I.H.P.
+
+    Projected      Projected area of propeller x speed of ships in knots. cubed
+    area         = ------------------------------------------------------
+    of constants                         I.H.P.
+
+  Expanded area constants may be obtained and used in the same way.]
+
+The discussion which followed was opened by Mr. Holt. He said that if
+they were to have greater speed on the Atlantic, there was one point
+which was not alluded to in the paper, and that was the total
+abolition of cargo on board the great passenger steamers. If vessels
+were built solely for passenger traffic, they would be able to insure
+greater speed by reason of the greater slightness in build and the
+additional space at the command of the designer. The existing Atlantic
+express steamer was far too heavy, and might, if cargo was dispensed
+with, be made with finer lines and more yacht-like. He looked on the
+proposition to fit such vessels with longitudinal bulkheads with great
+fear. If a collision took place--such, for example, as that which sunk
+the Oregon--water would get access to one side only of the ship, and
+it was not at all improbable that if a sea was on, she would turn
+right over. At all events, very serious risk would be involved.
+
+Mr. W.H. White, Chief Constructor to the Admiralty, said the question
+of twin screw propulsion was one of special interest to himself, and
+had been so for many years. In 1878 he dealt with it as fully as he
+then could on the basis of the Admiralty data, and he then ventured to
+say everything in favor of twin screws that Mr. John had said in his
+paper. If greater power than that now used in such a ship as the
+Etruria, for example, were demanded, two screws must be used. Good as
+are the results obtained with the Etruria, it was by no means certain
+that still better might not be had. If she had been fitted with two
+screws instead of one, very great advantage would be gained by the
+greater submergence of the twin screws, as thus racing would be almost
+wholly prevented.
+
+Mr. Calvert urged that more attention should be devoted to studying
+the relative values of different portions of the propeller.
+
+The sitting was then suspended. In the afternoon, as we have already
+stated, the members visited the steamship Germanic on the invitation
+of Messrs. Ismay, Imrie & Co., subsequently proceeding to Messrs. Cope
+Brothers' tobacco works, and thence to the exhibition, where the
+dinner of the Institution took place in the evening.
+
+On Friday morning no paper was read; some official business was
+transacted, and this being done, the discussion on Mr. John's paper
+was resumed.
+
+Mr. Biles remarked that there were many advantages in the use of twin
+screws which had not been sufficiently taken into account. When a ship
+with twin screws was being handled in dock there was greater
+maneuvering power, and therefore less liability for the ship to come
+in contact with the walls, although, if she did so, there would be
+greater probability of damage to the propellers. He thought means
+could be easily devised of protecting the screws when the ship was in
+dock. Another of the incidental advantages connected with twin screws
+was that smaller engines and smaller propellers were required, and
+therefore they might run them at a higher speed. They would also get
+lighter machinery with twin screws, and there would be less liability
+to have bad castings and forgings in the smaller engines, and of
+course the cost would be less.
+
+With respect to the question of the middle line bulkheads, he could
+not quite agree with Mr. John as to the great advantages of them in a
+big passenger steamer. He thought there would be greater difficulty in
+managing a ship so built if she was in danger of sinking. Increased
+subdivision in a longitudinal direction was a very desirable thing,
+and almost necessary for a condition of immunity from sinking. In
+future Atlantic steamers longitudinal bulkheads should be placed not
+in the middle line, but nearer the sides of the ships, and they should
+recognize the fact that they had engines and boilers in different
+compartments, and make arrangements whereby the ship would still
+float, although the doors in these compartments were kept open. The
+proper way to arrive at that was to have a ship with great beam, and
+to have two longitudinal bulkheads at considerable distances from the
+sides of the ship, subdivided as completely as possible, both under
+and above water, so that, even supposing they got water into the space
+between one bulkhead and the side of the ship, they would have
+sufficient buoyancy in the other parts of the ship to keep her afloat.
+Broad ships must necessarily mean deep ships, in order to have comfort
+at sea. They were limited in length, and first came the question how
+many passengers they wanted to carry. The experience of a ship like
+the America--which was only 400 ft. in length--showed it was not
+necessary to go to great length to have great speed. A ship of 400 ft.
+to 430 ft. in length, 65 ft. of beam, and with a depth of 45 ft.,
+would be a ship of proper dimensions for the Atlantic trade, and he
+believed it quite possible to build a vessel of special construction
+of about 7,000 tons gross register which should steam with less
+consumption of coal than the Umbria and Etruria at a rate of 22 knots,
+crossing the Atlantic from Liverpool to New York in six days. He
+thought that was likely to be the vessel of the future, and that it
+would be quite as commercially successful as the Umbria or Etruria.
+
+Mr. J. Campbell remarked that at present the great American liners had
+only the ordinary compound engines, and he thought that, instead of
+converting them to triple expansion, they should take a step further
+at once, and adopt quadruple expansion engines. This class of engines
+was being very successfully built in various parts of the country. He
+should recommend the adoption of a three-crank six-cylinder engine.
+
+Mr. Hamilton did not think it had been demonstrated that greater
+efficiency had been got out of twin screws than out of single screws;
+but there was no doubt they would tend to additional safety.
+
+Mr. Martell said that when they had got satisfactory data, twin screws
+would be adopted for ships requiring great speed; but they had not got
+that data at present.
+
+Admiral Sir John Hay, referring to twin screws as applying to
+sea-going steamers which might be employed for imperial defense, said
+it was quite certain that the defense of their extended commerce
+would always require to be assisted by ships such as the Oregon and
+other magnificent vessels which had been used for that purpose on a
+recent occasion. He believed that for war purposes the twin screw was
+recognized by all naval men as having very many advantages. If that
+were so, it was quite evident that it would be a great advantage,
+under such conditions as occurred at the loss of the Oregon, if the
+compartments could be made completely water-tight; and the twin screw,
+with the separation of the ship longitudinally, gave them the very
+greatest possible protection. They could not trust to bulkheads that
+were only closed occasionally by doors. What was required for war
+purposes was the entire and complete isolation of different parts of
+the ship, having always practically closed communications between
+them.
+
+Mr. John then replied on the general discussion. He was pleased to
+find that they had faith in the future of the twin screw and of
+subdivision. The public had a right to demand greater safety than they
+at present had on the Atlantic, or could have with a single screw.
+
+       *       *       *       *       *
+
+
+
+
+EXAMINATION QUESTIONS IN GENERAL CONSTRUCTION.
+
+
+The following is a copy of the last examination paper given to
+candidates who are desirous of employment in the constructive
+departments of the municipality of New York:
+
+N.B.--In case candidate does not remember formula or method of solving
+any problem submitted to him, let him name any work upon the subject
+where such formula or method may be found.
+
+1. What is civil engineering?
+
+2. Have you ever pursued a course of study in any educational
+institution, or with any civil engineer, which would fit you for the
+position of assistant engineer? If so, state when and with whom; state
+also, in detail, what experience you have had.
+
+3. Have you ever had responsible charge of any public work? If so,
+state particulars.
+
+4. Solve the following according to the algebraic signs:
+
+      --------------------------------------
+     / (6-2/7 - 4-3/9) x 8-7/16
+    /  ------------------------ x 67873.367,     and show your work.
+  \/            4-4/12
+
+
+5. The population of a certain town in 1880 was 7,095; it having
+increased 25 per cent. in ten years, what was it in 1870? Show your
+work.
+
+6. How many feet, board measure, in the flooring of a room 20 feet by
+30 feet and 21/2 inches thick?
+
+7. Find value of x and y in the following equations:
+
+  2 x + 3 y = 33
+  4 x - y = 17.
+
+8. Find value of x in equation x squared - x - 40 = 170.
+
+9. Find value of x in equation
+
+          --------
+   a     / a squared - x squared   x
+   - +  /  ------- = -
+   b  \/      x squared     b
+
+10. Explain the meaning of the expression a1/2 x b3/4.
+
+11. What is a logarithm?
+
+12. What is the base of the common system?
+
+13. In making what calculations are logarithms useful?
+
+14. How do you find the logarithm of a number in a table of
+logarithms?
+
+15. What are similar triangles?
+
+16. How are similar triangles proportioned to each other?
+
+17. The sides of a polygon being prolonged, what is the sum of all the
+exterior angles equal to?
+
+18. How do you pass the circumference of a circle through three given
+points not in the same straight line?
+
+19. How do you describe a square in a circle?
+
+[Illustration]
+
+20. In the triangle, b being a right angle, what proportion does d b
+bear to a d and d c?
+
+21. How do you inscribe a regular hexagon in a circle?
+
+22. What proportion do circumference and areas of circles bear to
+their radii?
+
+23. How do you find the area of a regular polygon?
+
+24. Of an irregular polygon?
+
+25. Of a circle?
+
+26. How do you find the solid contents of a cylinder?
+
+27. Of a wedge?
+
+28. Of a pyramid?
+
+29. Find the contents of the wedge, base 20 feet by 30 feet, height 10
+feet, edge 15 feet.
+
+30. State the prismoidal formula; would you use it in calculating
+earthwork?
+
+31. Is a simple question in calculating areas.--Ed. _Eng. News_.
+
+32. How many and what parts of a plane triangle must be given to find
+the rest?
+
+33. Define the terms sine, co-sine, tangent, and co-tangent.
+
+34. What are natural sines, co-sines, etc.?
+
+35. What is a table of logarithmic sines, co-sines, etc.?
+
+30. Two sides and two angles of a plane triangle being given, how do
+you find the other parts?
+
+37. When two sides of a plane triangle and their included angles are
+given, how do you find the other parts?
+
+38. In the right-angled triangle, A B H express algebraically the
+value of the sine, co-sine, tangent, and co-tangent of angle A in
+terms of a, b, and h, they being the altitude, base, and hypothenuse
+of the triangle.
+
+39. What is the law of gravitation?
+
+40. Do you understand that there is any difference in the meaning of
+the terms gravitation and gravity?
+
+41. What is the law of falling bodies?
+
+42. Express algebraically this law, taking v = velocity of falling
+body; g = acceleration of gravity; and h = height.
+
+43. What is the center of gravity of a body?
+
+44. How is it found?
+
+45. Where is the center of gravity of a homogeneous body whose sides
+are all rectangles?
+
+46. What is the specific gravity of a body?
+
+47. What is the standard for solids and liquids?
+
+48. What for gases?
+
+49. What laws govern the pressure of liquids at rest?
+
+50. How do you find the number of gallons of water to the cubic foot?
+
+51. What is the weight of a gallon of water?
+
+52. What is the pressure per square inch on the side of a vessel at
+the depth of 10 feet below the surface of the water?
+
+53. What will be the theoretical volume of discharge per second from a
+reservoir through a pipe 1 foot in diameter, discharging at a depth of
+100 feet below the surface of the water?
+
+54. How many gallons of water will be discharged through a pipe 1 foot
+in diameter, 328 feet long, head 131/2 feet, coefficient of flow =
+0.007?
+
+55. State how many men are needed to make up a full party for a survey
+of a preliminary line or location of a public work, such as a railroad
+or aqueduct.
+
+56. State also their several duties.
+
+57. For what purpose is the magnetic needle used in surveying land?
+
+58. What is a traverse table and for what used?
+
+59. How do you set out a circular curved line upon the ground?
+
+60. If an obstacle occurs to alignment, state how you would overcome
+it upon straight lines, also upon curves.
+
+61. The radius of a curve being given, and angle of intersection of
+the two tangents, how do you find the length of the tangent from their
+intersection to the beginning of the curve?
+
+62. Describe an engineer's transit, and name its adjustments.
+
+63. Describe a Y level, and name its adjustments.
+
+64. How many kinds of leveling rods do you know of?
+
+65. State how they are graduated, and how they can be read to the
+1/1000 of a foot.
+
+66. Show a form of field-book for transit notes used when "running"
+curves, and place thereon notes of a 5 deg. curve for 1,000, with two
+intermediate "set-ups."
+
+67. Show a form of level-book, and place therein sufficient figures to
+show your method.
+
+68. What are cross-sections?
+
+69. How do you set slope stakes for excavation and embankment?
+
+70. What is a grade line?
+
+71. What proportion of the breaking weight of a beam would you
+consider a safe load?
+
+72. With the load uniformly distributed, what fractional part of the
+whole weight may be considered, in all calculations, as being carried
+at the center?
+
+73. Suppose a beam supported at both ends, and take w = weight, l =
+length of beam, b = breadth, d = depth, s = breaking weight. Express
+algebraically the value of s in terms of the other quantities.
+
+74. Sectional area being 36 square inches, which would be the stronger
+section, 6 by 6 or 4 by 9?
+
+75. Make a design for a pair of rafters, connected by a tie-beam, for
+a roof 30 feet span, showing the dimensions of the several parts and
+the manner of connecting them. State in detail your method of
+obtaining the several dimensions.
+
+76. How do you apply the principle of the parallelogram of forces in
+determining the strain on the various members of a structure?
+Illustrate graphically.
+
+77. What should be the thickness at the top and base of a retaining
+wall 15 feet high, built to retain ordinary earth? Show your method of
+obtaining the required dimensions, also a sketch of the wall, showing
+how it should be founded.
+
+78. A reservoir is to be built, depth of water 10 feet. If the walls
+are built of masonry, find the thickness of the same, and state how
+they should be built. Show your work.
+
+79. What is an arch, of how many forms, and of what may it be
+constructed?
+
+80. Can you state how you would find the thickness of an arch of
+stone, span and rise being given?
+
+81. Define the intrados and extrados of an arch.
+
+82. Where should the line of resistance to pressure be found in an
+arch in order to retain its stability?
+
+83. Can you find the thickness of the abutments, the rise and span of
+the arch being given?
+
+84. In a semicircular arch, where is the horizontal thrust greatest
+and where least?
+
+85. Name the common kinds of stone used in building.
+
+86. Define the terms "quarry-faced," "rough-pointed," "fine-axed,"
+"bush-hammered," as applied to the dressing of stone.
+
+87. Describe "rubble" masonry, "ashlar" masonry, and "broken ashlar"
+masonry.
+
+88. What are "headers" and "stretchers"?
+
+89. What should be the proportion of "headers" to "stretchers"?
+
+90. How would you prepare the foundation for a heavy wall, and how
+deep should it be excavated?
+
+91. How are walls founded on soft or yielding materials?
+
+92. Describe a good quality of bricks, and state how you would know a
+good brick from a poor one.
+
+93. In how many ways is brickwork "bonded" to make good work in heavy
+walls?
+
+94. What is hydraulic cement, and how many kinds do you know of?
+
+95. Which do you consider the better quality, Rosendale or Portland,
+and why?
+
+96. What is mortar composed of, and how mixed?
+
+97. What kind of sand should be used, and how do you test its quality?
+
+98. What is the meaning of the term "setting" as applied to cement?
+
+99. How would you test cement?
+
+100. What is concrete, of what composed, and in what proportion should
+its ingredients be mixed?
+
+101. Name the common kinds of wood used in building.
+
+102. What kind of timber resists decay longest under ground?
+
+103. How may timber be preserved from decay?
+
+104. What do you understand by limit of elasticity as applied to a
+beam under strain or pressure? What is meant by the neutral axis of a
+beam?
+
+105. What is the tensile strength of a good quality of wrought iron
+per square inch?
+
+106. For what parts of a structure may cast and wrought iron be used
+in reference to tension and compression?
+
+107. Make a sketch of the form of cast-iron beam best adapted to
+resist a transverse strain.
+
+       *       *       *       *       *
+
+
+
+
+CELEBRATION OF THE FIVE HUNDREDTH ANNIVERSARY OF THE UNIVERSITY OF
+HEIDELBERG, AUGUST, 1886.
+
+
+The wave of pleasure and enjoyment which flooded everything has
+passed. Heidelberg, usually so quiet, assumed the role of a city of
+the world, and all was bustle and excitement in the streets, which
+were hung with flags and other decorations. The trains constantly
+brought new accessions to the crowd, and gayety and mirth reigned
+supreme.
+
+The dedication of the renovated _Aula_ of the University served as a
+prelude to the festivities of the week. On this occasion a splendid
+flag, embroidered by order of the wives of the faculty of the Academy,
+an equally costly cover for the scepter, and a silver inkstand were
+added to the treasures of the University. Conspicuous among the
+numerous presents received were a richly carved set of furniture--the
+gift of former students from Switzerland--and all the publications of
+certain book dealers.
+
+On the afternoon of August 2, the Grand Duke and Duchess arrived in
+Heidelberg, where they were received with much enthusiasm. They
+remained at the modest palace during the time of the jubilee, and
+whenever they appeared they were greeted with expressions of
+patriotism and love. On the evening of the 2d, the _Oberburgermeister_,
+Dr. Wilckens, extended a hearty welcome to the guests who had gathered
+in the over crowded hall. Vincenz Lachner conducted the musical part of
+the entertainment, which was charming. The German Crown Prince arrived
+early on the 3d, so as to accompany his royal cousins to the service in
+the beautifully decorated _Heiliggeistkirche_, on which occasion Prof.
+Bassermann spoke with great effect. At 11 o'clock, the Court appeared in
+the _Aula_, where the Grand Duke presided, in virtue of his office of
+"Rector Magnificentissimus." His address was followed by those of the
+Crown Prince; the _Prorector Geheimrath_, Dr. Bekker; Edward Zeller, of
+Berlin; Jules Zeller, of Paris; and others. In the evening the citizens
+and strangers were attracted to the _Jettenbuehel_ by the festival at the
+castle; from 7:30 until 10 o'clock the nobility held court in the
+_Bandhause_. The scene was like fairyland, all the outlines of the
+castle were marked by thousands of small lights, and the court was
+lighted by great candelabra. In the ever-increasing crowd it was
+difficult to find a place and to obtain refreshments, which were given
+out in immense quantities by the State.
+
+On the morning of the 4th the people thronged again to the
+_Heiliggeistkirche_ to listen to the address of the _Geheimrath_, Dr.
+Kuno Fischer, on the fate of the Palatinate and Heidelberg, which was
+preceded and followed by music. After this the participants in the
+festival were brought together by a dinner in the Museum Hall, and
+seldom have speeches so inspired an audience as did those of the Grand
+Duke and the Crown Prince. Never has Heidelberg seen such a
+torch-light procession as that formed by the students in honor of
+their Rector; 3,000 torches lighted him to the City Hall. He thanked
+them, and proposed cheers for the Crown Prince.
+
+On the morning of the 5th there was the presentation of degrees. In
+the afternoon a special train carried four hundred people to
+Karlsruhe, where the royal party held a great reception. The capital
+was decorated with flags, the city parks were lighted with Bengal
+lights, there was music, and a song by the patriotic bard Vierordt was
+sung.
+
+All the splendor and interest shrank into insignificance before the
+grand historical procession on the morning of the 6th, which made a
+lasting impression on the minds of all. The throng of 100,000 people
+watched quietly while the whole history of the Palatinate passed in
+review before them. The procession illustrated this history much
+better than it could have been told by any professor or any book.
+There was not a vacant space to be found, extra trains having brought
+more spectators, and yet everything passed off quietly and without
+accident. In the evening there was a heavy shower, which freshened
+everything, leaving no ill effects to be seen the next morning, which
+was more than could be said of many of those who attended the imposing
+_Commerse_ of the Heidelberg students. As a former student, the Grand
+Duke appeared among the 6,000 visitors at the _Commerse_, where he
+presided and spoke enthusiastically of the Emperor. Other speeches
+followed, until the conversation became so animated that even Von
+Treitschke, who was received with an ovation, could not be heard. At
+midnight the court retired and the _Fidelitas_ succeeded to their
+rights.
+
+On the 7th the time was spent in excursions and carousing until the
+illumination of the castle began. I never saw an illumination of the
+ruins which could compare in beauty with that of the 7th. The night
+was favorable for fireworks, until finally they were rivaled by the
+moon, numerous boats trimmed with colored lanterns passed along the
+river, there were fire-wheels on the bridge, water fireworks on the
+river, and the quiet was disturbed alternately by the rockets and
+music, and when the names of the Grand Duke and Duchess, crowned with
+brilliant fire, appeared over the water, there was an involuntary
+outburst of enthusiasm. If the old Elector and Electoress could have
+been present at the closing entertainment of the jubilee, on the
+evening of the 8th, they would have rejoiced to see the new life
+brought to the ruins by their successor.--_Illustrirte Zeitung._
+
+       *       *       *       *       *
+
+
+
+
+MANUFACTURE OF LEATHER IN RUSSIA.
+
+
+From this extensive paper it appears that the matters chiefly used in
+tanning are the bark of the oak, containing from 6.04 to 4.37 per
+cent. of tannin according to the season, that of willows, of the elm,
+and the birch. The leaves of the arbutus, employed in the governments
+of Kasan, Viatka, and Perm, contain about 16 per cent. of tannin,
+while the root of wild sorrel (_Rumex acetosella_) contains 12 per
+cent. For removing the hair from hides, a lye made from wood ashes is
+still employed. The softening of the leather is effected by means of
+the excrement of dogs, which acts on the leather by means of the
+biliary acid present, which forms with soda a kind of soap. After
+tanning, white Russia leather is coated with a mixture of tar and seal
+oil. Black Russia leather is dyed with alum, extract of sanders, and
+ferrous sulphate. Horse hides are tanned to a great extent for sole
+leather.--_M. Ryloff._
+
+       *       *       *       *       *
+
+
+
+
+IMPURITIES IN PHOTOGRAPHIC CHEMICALS, AND TESTS FOR SAME.
+
+
+[Table referred to in a paper read before the Birmingham Photographic
+Society by G.M. JONES, M.P.S.]
+
+  ------------------+---------------------+----------------------------------
+  SUBSTANCE         |     IMPURITIES      |             TESTS.
+                    |  POSSIBLY PRESENT.  |
+  ------------------+---------------------+----------------------------------
+  Ammonia,          | Carbonic acid       | Renders lime-water milky.
+  NH_{3}            |                     |
+  Molec. Wt. 17     | Dissolved solid     | Residue left on evaporation.
+                    | matter              |
+                    |                     |
+                    | Chlorides           | After acidulating with nitric acid,
+                    |                     | it gives a precipitate with silver
+                    |                     | nitrate, which after washing is
+                    |                     | readily soluble in ammonia and
+                    |                     | reprecipitated by nitric acid.
+                    |                     |
+                    | Sulphates           | After acidulating with nitric acid,
+                    |                     | it gives a precipitate with
+                    |                     | barium nitrate.
+                    |                     |
+                    | Lime                | A white precipitate with oxalate
+                    |                     | of ammonium.
+                    |                     |
+                    | Lead is often       | Black precipitate with sulphureted
+                    | present, derived    | hydrogen.
+                    | from the action     |
+                    | upon flint glass    |
+                    | bottles             |
+                    |                     |
+  Nitric acid.      | Traces of           | After dilution it gives a
+  H, NO_{3}         | sulphuric acid      | precipitate with barium nitrate.
+  Molec. Wt. 63     |                     |
+                    | Chlorides           | After dilution it gives a
+                    |                     | precipitate with silver nitrate.
+                    |                     |
+                    | Peroxide of nitrogen| The acid is yellow.
+                    |                     |
+                    | Iodine may be       | After dilution and cooling it gives
+                    | present if the acid | a blue color with starch, paste,
+                    | be prepared from    | or mucilage.
+                    | sodium nitrate      |
+                    |                     |
+  Hydrochloric      | Free chlorine       | Liberates iodine from solution
+  acid, HCl         |                     | of potassium iodide. See also
+  Molec. Wt. 36.5   |                     | "Chlorides," nitric acid.
+                    |                     |
+                    | Sulphuric acid      | As above for nitric acid.
+                    |                     |
+                    | Perchloride of iron | Yellow color. Brown precipitate
+                    |                     | with ammonia added till it
+                    |                     | smells slightly.
+                    |                     |
+  Sulphuric acid,   | Bisulphate of       | Residue on evaporation.
+  H_{2}SO_{4}       | potassium           |
+  Molec. Wt. 98     |                     |
+                    | Sulphate of lead    | Milkiness on dilution. May be
+                    |                     | completely freed from lead by
+                    |                     | diluting with three or four times
+                    |                     | as much water, and allowing
+                    |                     | to settle.
+                    |                     |
+  Acetic acid       | Water               | Does not solidify when cooled
+  (glacial),        |                     | to 17 deg. C. (53º F.)
+  H C_{2}H_{3}O_{2} |                     |
+  Molec. Wt. 60     | Sulphurous and      | White precipitates with silver
+                    | hydrochloric        | nitrate.
+                    | acids               |
+                    |                     |
+                    | Aldehyde, or        | Blackens in the light after adding
+                    | volatile tarry      | silver nitrate.
+                    | matter              |
+                    |                     |
+                    | Organic sulphuric   | Smell of garlic.
+                    | acid                |
+                    |                     |
+  Citric acid,      | Tartaric acid       | Strong solution of potassium.
+  H_{3}C_{6}        |                     | Acetate added to a strong solution
+  H_{5}O_{7}H_{2}O  |                     | of the acid will deposit white
+  Molec. Wt. 210    |                     | crystalline bitartrate.
+                    |                     |
+  Pyrogallic acid   | Metagallic acid     | Black residue, insoluble in water.
+  (C_{6}H_{3})HO_{3}|                     |
+  Molec. Wt. 126    |                     |
+                    |                     |
+  Silver nitrate,   | Free nitric acid    | Reddens litmus paper. (Neutral
+  AgNO_{3}          |                     | silver nitrate does not
+  Molec. Wt. 170    |                     | affect litmus.)
+                    |                     |
+  Potassium         | Chlorides and       | Same as for ammonia.
+  carbonate         | sulphates           |
+  K_{2}CO_{3}       |                     |
+  Molec. Wt. 138    |                     |
+                    |                     |
+  Potassium         | Potassium  carbonate| A strong solution is alkaline to
+  iodide, KI        |                     | test paper.
+  Molec. Wt. 166    |                     |
+                    | Sulphates and       | Same as for ammonia.
+                    | chlorides           |
+                    |                     |
+                    | Potassium iodate    | A pretty strong solution becomes
+                    |                     | yellow from liberation of iodine
+                    |                     | on addition of dilute sulphuric
+                    |                     | acid or, better, a strong solution
+                    |                     | of citric acid.
+                    |                     |
+  Potassium         | Similar to          | See potassium iodide.
+  bromide, KBr      | potassium iodide    |
+  Molec. Wt. 119    |                     |
+                    |                     |
+  Sodium carbonate, | Chlorides and       | Same as for ammonia.
+  Na_{2}CO_{3}      | sulphates           |
+  Molec. Wt. 106    |                     |
+                    |                     |
+  Sodium chloride,  | Chloride of calcium | Oxalate of ammonium (after
+  NaCl              | Chloride of         | addition of a little acetic acid)
+  Molec. Wt. 58.5   | magnesium           | gives a milkiness, or precipitate,
+                    |                     | indicating calcium; filter this
+                    |                     | out and add ammonia, chloride of
+                    |                     | ammonium, and phosphate of sodium
+                    |                     | (clear solutions). A precipitate
+                    |                     | indicates magnesium. Both the above
+                    |                     | cause dampness in wet weather.
+                    |                     |
+                    | Sodium sulphate     | As for "sulphates" in ammonia.
+                    |                     |
+  Potassium         | Potassium carbonate | Effervescence with dilute acids,
+  cyanide, KCN      | nearly always       | giving off a gas carbonic
+  Molec. Wt. 65,    | present             | anhydride, which renders
+  and hydrate, KHO  |                     | lime-water turbid.
+  Molec. Wt. 56     |                     |
+  Kaolin            | Chalk               | Effervescence with dilute acids.
+                    |                     |
+  Water,            | Sulphates and       | Same as for ammonia.
+  H_{2}O            | chlorides           |
+  Molec. Wt. 18     |                     |
+                    | Calcium carbonate,  | Deposited by boiling. Test as
+                    | temporary hardness  | for calcium chloride. See
+                    |                     | sodium chloride.
+                    |                     |
+                    | Ammonia, almost     | Brown coloration, or
+                    | always present in   | precipitate with Nessler's
+                    | distilled and rain  | reagent.
+                    | water               |
+                    |                     |
+  Gelatine          | Alum                | Ash, sometimes as much as ten
+                    |                     | per cent.
+                    |                     |
+                    | Fatty matter        | Separated by precipitation with
+                    |                     | alcohol. Dissolved out by ether
+                    |                     | or benzine, and left as a residue
+                    |                     | on evaporation of the solvent.
+                    |                     |
+                    |                     |
+  Ammonium bromide  | Potassium bro-      | Leaves a residue when heated.
+  (NH_{4})Br        | mide or other       |
+  Molec. Wt. 98     | non-volatile        |
+                    | bodies              |
+                    |                     |
+                    | Ammonium chloride   | Same as for chlorides in
+                    |                     | ammonia.
+                    |                     |
+  Pyrogallic acid   | Powdered glass      | Left behind on solution.
+                    |                     |
+  Potassium iodide  | Potassium bromide   | The crystals of bromide are
+                    |                     | usually more transparent than
+                    |                     | those of iodide, but no reliance
+                    |                     | can be placed on this.
+                    |                     |
+  Silver nitrate    | Potassium nitrate,  | Will not yield the full quantity
+                    | sometimes present   | of chloride on precipitation
+                    | in the fused        | with HCl. Gives a purple color to
+                    | sticks--not in      | flame.
+                    | the crystals        |
+                    |                     |
+  Sulphuric acid    | When vended as pure,| No easy test can be given, as the
+                    | it invariably       | substances are so numerous some of
+                    | contains a trace of | them volatile, and most require
+                    | iron. Common acid is| separation from the acid before
+                    | also liable to      | detection.
+                    | contain arsenic,    |
+                    | selenium, thalium,  |
+                    | and many other      |
+                    | substances.         |
+                    |                     |
+                    | Organic matter, as  | Gives a brown color to the acid.
+                    | a piece of straw    |
+                    | in a carboy of acid |
+                    |                     |
+  Hydrochloric acid | Arsenic             | Marsh's test.
+                    |                     |
+                    | Some yellow samples | Reinsh's test; a small piece of
+                    | contain no iron,    | copper foil becomes coated
+                    | but an organic salt,| on boiling in dilute acid.
+                    | and give an alkaline|
+                    | ash on ignition of  |
+                    | the residue after   |
+                    | evaporation         |
+                    |                     |
+  Calcium chloride  | Calcium hydrate     | The clear filtered solution made
+                    |                     | with distilled water is alkaline
+                    |                     | to test paper, and gives a
+                    |                     | precipitate on breathing into it
+                    |                     | through a tube.
+                    |                     |
+  Pure (?) chemicals| Broken glass, bits  | These impurities either float or
+   generally        | of straw, wood,     | sink on solution, and may easily
+                    | paper, etc.         | be seen.
+  -------------------------------------------------------------------------
+
+G.M. JONES, M.P.S.
+
+       *       *       *       *       *
+
+
+
+
+THE CATASTROPHE AT CHANCELADE.
+
+
+The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885,
+under circumstances that are still fresh in the minds of all, have
+gained a celebrity that renders it unnecessary for us to revert to the
+details of the catastrophe. It will suffice to recall the fact that
+after the accident a private committee was formed for the purpose of
+making an attempt to save the five victims who had been surprised in
+the drifts, and who happened to be in the bottom levels.
+
+[Illustration: FIG. 1.--PHOTOGRAPHIC EXPLORING APPARATUS.]
+
+The Lippmann establishment at once offered to make a boring by means
+of which it would be possible to communicate with the galleries in
+which the men were imprisoned, but, despite the most active efforts,
+success was found impossible. In order to satisfy public opinion, the
+committee resolved to bore a well 12 inches in diameter to a depth of
+23 feet, that should permit of reaching the gallery; but this did not
+render the latter accessible. How was it to be seen what had occurred,
+how was it to be made certain that the men were dead, and that all
+hope of rescue must be abandoned? To Mr. Langlois, a Parisian
+photographer, was confided an order to construct a special apparatus
+which might be let down to the bottom of the well by a cord, and
+which, being capable of operating from a distance, should furnish the
+required information through sensitized plates. As may be seen, this
+operation presented peculiar difficulties, although Mr. Langlois was
+enabled to overcome these with much skill.
+
+The photographic apparatus that the ingenious operator constructed was
+contained in a metallic case that could be let down into the bore
+hole. The upper and lower parts of the contrivance were provided with
+incandescent lamps, that could be lighted or extinguished from a
+distance, by means of conductors. The photographic apparatus, properly
+so called, formed of an objective and camera with its sensitized
+plate, was inclosed in a cylinder 31/2 inches in diameter. By means of a
+cord drawn at the mouth of the well, the apparatus could be made to
+issue from its vertical sheath, and to pivot around its axis so as
+take views in different directions (Fig. 1).
+
+The entire affair was suspended by twelve-foot iron rods, connected
+with each other end for end.
+
+In using the apparatus, the operating was done in a shanty, which
+served as a dark room. The device was let down into the bore well
+until it touched bottom. At this moment a cord was pulled so as to
+raise the camera, and then a few moments were allowed to elapse in
+order that the apparatus might become immovable. As the objective was
+all the time in the dark, it had neither cap nor shutter, but was
+unmasked from the beginning of the operation.
+
+In order to form an impression on the plate, it was only necessary to
+give light; this being easily done by passing an electric current by
+means of a commutator, so as to light the incandescent lamps. At the
+end of the exposure, the lamps were extinguished and the entire
+apparatus was immersed in darkness. The mean time of exposure was from
+four to five minutes. The apparatus was then hauled up, and the
+negative developed.
+
+The experiments could be renewed as often as necessary, and the
+apparatus be pointed in all directions by turning it a certain number
+of degrees by means of a lever attached to the upper rod. In this way
+were obtained various views of the inaccessible gallery in different
+planes.
+
+[Illustration: FIGS. 2 AND 3.--REPRODUCTION OF PHOTOGRAPHS TAKEN IN
+THE INACCESSIBLE GALLERIES.]
+
+We reproduce herewith two of Mr. Langlois' most interesting
+photographs. One of these shows the head of the corpse of a young
+miner whose face stands out in relief against the side of the gallery
+(Fig. 2) the other shows a wheel and a lot of debris heaped up
+pell-mell (Fig. 3).
+
+The series of proofs obtained from small negatives, two inches square,
+gave the completest sort of information in regard to the aspect of the
+subterranean gallery.
+
+The exact place where the boring had been done and the entire and
+broken pillars were recognized, as was also the presence of two
+corpses, thus showing that it was indeed here that it would have been
+necessary to act in order to render aid to the unfortunates.
+
+[Illustration: FIG. 4.--FAULT THAT CAUSED THE ACCIDENT.]
+
+In Fig. 4 is shown the appearance of the great fault that caused the
+accident at Chancelade. It seems to us that this method of
+photographing inaccessible subterranean galleries ought to receive
+numerous applications in the future.--_La Nature._
+
+       *       *       *       *       *
+
+
+
+
+SOMZEE'S NEW GAS-BURNERS.
+
+
+With the object of effecting a very intimate mixture of gas and air,
+and of causing this mixture to reach the point of ignition at as high
+a temperature as possible, M. Leon Somzee, of Brussels, has designed
+several new forms of gas burner, which we now proceed to describe and
+illustrate, from particulars and by drawings kindly supplied by an
+esteemed Brussels correspondent.
+
+The high-power burner shown in Fig. 1 effects perfect combustion of
+the heated mixture of air and gas, which is introduced by the draught
+determined by the arrangement. What chiefly distinguishes this burner
+from others of its class is the fact that it is perfectly suited to
+domestic lighting--that is to say, it may be arranged for a
+comparatively small consumption of gas, while giving an increase of
+250 per cent. of light.
+
+[Illustration: FIG. 1. and FIG. 2. INCANDESCENT AND HIGH-POWER
+BURNERS.]
+
+The burner proper is a cage or basket of specially prepared magnesia,
+which yields a warmer tone of light than any obtained hitherto, while
+not requiring so high a temperature before combustion. The cap, made
+of a fire-resisting substance, fits on to a tubular arrangement, R,
+fixed in the upper portion of the body of the burner. The latter is
+supplied by air entering at the cone, O, which terminates the inner
+chamber, K, of the heater, and also by that drawn in by the rising
+column of gas, passing before the orifices, D, which may be regulated
+at will. The small burner, I, which is kept constantly alight, heats
+the central compartment, K, the sides of which transmit heat to the
+gas circulating in the annular casing, L, of the compartment. The
+heated gas passes, by the passage, AA¹, into the space, C, where it
+becomes intimately mixed with the air entering at OP, and also with
+the outer air arriving by the lateral apertures, D.
+
+The _vis viva_ of the jet is diffused through this mixture, which thus
+becomes very intimate, when it penetrates into the tubular
+arrangement, R; combustion now taking place at the top, while the
+refractory cap emits a bright orange light of great steadiness. As it
+is not the flow of gas which determines the entrance of the outer air,
+the former may be used at any pressure--an advantageous arrangement in
+all respects.
+
+When the small burner, I, in the lower chamber is lighted, the
+products of combustion issue by the orifice, O, of the compartment,
+terminating in a needle like that of the steam injector; and the jet
+draws along the air entering the apertures, PP, above the cone. The
+gas from the pipe, arriving from the annular space, L, fills the two
+lateral pockets shown in dotted lines, and passes through the
+orifices, AA¹, which communicate with the upper chamber of the
+burner. The manner in which it is conveyed thence to the tubular
+arrangement has already been described.
+
+Fig. 2 shows a more simple method of carrying out the same principle,
+and of effecting a considerable saving in gas for a given intensity of
+light. In this form, a wick, T, impregnated with an alkaline earthy
+solution, a few seconds after lighting, affords a focus of white light
+remarkable for its steadiness and brilliancy. A draught of air is
+created by a jet of gas issuing from the hollow needle, B, and passing
+through the vessel, D, which is provided with orifices, O, for the
+entrance of air. The air and gas pass from D into C, whence (after
+their intimate mixture is effected) they pass into the tubular
+arrangement, F, at the top of which combustion takes place.
+
+To regulate the proportions in which the air and gas should mingle, in
+order that the combination should be as intimate as possible, the air
+inlet is made variable by a perforated collar, which permits of the
+orifices, O, being more or less covered. The other proportions of the
+burner--that is to say, the relative capacity of the two compartments
+and the length of the hollow needle--are determined by the sectional
+area of the supply-pipe for the gas, which is admitted under moderate
+pressure. Instead of a wire-gauze cap, impregnated with a solution of
+metals or of salts, two fine platinum wires may be used--one bent into
+the form of a semicircle of about an inch radius, and the other (of
+slightly larger diameter) rolled spirally round the former. When both
+ends of the two wires are connected with the upper portion of the
+tubular arrangement (which in this case is flattened), and the gas is
+ignited at the burner, the metallic arc becomes red hot, and then
+brightly incandescent, emitting a light, less brilliant indeed than
+with magnesia, but of remarkable steadiness.
+
+In this case the production of light is chiefly due to the fact that
+calorific condensation, caused by the use of the helicoidal coil
+surrounding the curved wire, prevents loss of heat in this conductor.
+In these forms of high-power burner, in which the gas is used directly
+for the production of light, the difficulty generally encountered of
+heating the air (present in a larger volume than the gas) has been
+successfully overcome.
+
+Fig. 3 shows the straight and outspread flame burner with a special
+heater. In this arrangement the gas and air are heated before
+combustion, in the compartment, G, directly exposed to the action of a
+small Bunsen burner, R, which is placed (in an opaque glass) in the
+middle of a lyre-shaped figure formed by the two gas-pipes, AA. The
+burner proper consists of two fine annular passages meeting above, and
+emitting a thin annular sheet of gas over the guide, T, made of a
+white refractory substance placed between the two annular jets. The
+object of this guide is to stretch the incandescent sheet of flame,
+composed of several jets, and interpose friction, so as to prevent a
+too rapid ascent of hot gases.
+
+[Illustration: FIG. 3 and FIG. 4 REGENERATIVE BURNERS WITH INVERTED
+FLAMES.]
+
+The luminous focus is placed within a glass globe, C, mounted on the
+bell, B, of the heater; and the external air enters this bell,
+mingling with the products of combustion of the heating burner, R. The
+portion, D, of the annular passage, B, being made of a highly
+conductive metal, the gas becomes heated in passing to the burner, so
+that both gas and air are raised to the same temperature by the time
+they reach the orifices of the burner. Instead of prolonging the
+gas-pipe to the point of bifurcation, a chamber may be arranged
+immediately below the guide, for the gas and air to become intimately
+mixed by passing through several perforations or wire gauze, receiving
+the excess of heat from the white porcelain guide. The admission of
+gas to both the main and heating burners is regulated by a double
+valve in the pipe; but this arrangement may be used without any
+previous heating of the gas and air.
+
+Fig. 4 shows a similar arrangement to that above described, but
+reversed; the gas and air being previously heated by the products of
+combustion. The two pipes, D, lead the gas to the burner; and the
+incandescent sheet of flame is drawn over a white refractory
+substance, having in its center an orifice through which the hot gases
+rise to the upper portion of the burner. The luminous sheet is spread
+out all the better on account of this return of the flames, which also
+causes the mixture of air and gas to be more complete than when they
+rise directly. The gas escapes horizontally from the orifices of the
+annular burner, B, and mingles with the double current of hot air
+which rushes in above the flame inside the globe, and also below
+through the central portion of the burner.
+
+This lamp throws its light vertically downward; and its illuminating
+power may be increased by providing, above the incandescent sheet, a
+reflector, which diverts into a useful direction the rays thrown
+toward the ceiling. In this arrangement of lamp the flame is
+excessively condensed by its being turned back over the refractory
+guide; and this condensation greatly favors the production of light.
+On the other hand, the combustion of the gas is very perfect, because
+the currents of hot air are thrown directly upon the two sides of the
+flame; and thus the reciprocal action becomes more intense. Lastly,
+the division of the gas into a large number of small jets, in contact
+with which the hot air forms an intimate mixture, causes a greater
+quantity of molecules to partake in the combinations; thus affording a
+proportionate increase of temperature in a given space and time.
+
+[Illustration: FIG. 5. REGENERATIVE BURNER WITH FLAME DEFLECTED
+OUTWARD.]
+
+Owing to these various circumstances, the final effective duty of this
+burner is advantageous, so that it yields an illuminating power which
+may be put at from 200 to 250 per cent. above that of ordinary
+burners, and about 25 per cent. more than that of other regenerative
+burners. The flame is comparatively steady; the loss due to the
+friction over the white porcelain being almost eliminated, because the
+flame only presses upon the guide for a small portion of its surface,
+and is only spread out to the extent of its dark zone.
+
+The contact between the incandescent sheet of flame and the guide may
+be made as short as desired, and the motion of the gaseous mass be
+directed by a simple button placed in the center of the burner; thus
+giving the form shown by Fig. 5, which, however, differs from the
+previous figure in the fact that the inverted flame is directed
+outward instead of inward.
+
+In this arrangement the button, T, is fixed in the middle of the
+burner, which is made cylindrical and annular, or may consist of a
+ring of small tubes, to which the gas is led by a single pipe; leaving
+the whole "furnace" free for the circulation of air and the products
+of combustion. This is the most recent development of the principle
+patented by M. Somzee in 1882, viz., the formation of an illuminating
+sheet of flame, spread out laterally, while heating the gas and air by
+the products of combustion.
+
+Figs. 6 and 7 show two forms of burner designed especially to give
+economical results with a small consumption of gas. The former is an
+ordinary Argand burner in which hot air is introduced into the upper
+portion of the flame, so as to increase the activity of combustion.
+The luminous sheet of flame is then spread out by a metal disk
+attached to the end of the tube, D, which introduces the air into the
+flame. The outer air becomes heated in its passage through the wire
+gauze, T, which absorbs the heat liberated in the interior of the
+apparatus, and also that which is radiated from the incandescent sheet
+and reflected by a metal shield, P, surrounding the dark part of the
+flame.
+
+[Illustration: FIG. 6. FIG. 7. TYPES OF ECONOMICAL BURNERS.]
+
+It is the combustion of gas, without the production of useful luminous
+effect inside the shield, which supplies the reflected as well as
+radiated heat to the air. The temperature is still further increased
+by the heat transmitted to the metal portion of the burner, and
+absorbed by the wire gauze, between the close meshes of which the air
+from outside is forced to circulate. Air is admitted inside the flame
+by the chimney, D, placed above the focus, and in which it is raised
+to a high temperature by friction on the upper part of the lamp glass,
+at E, and afterward by its passage through the horizontal portion of
+the bent tube. This tube is impinged upon on the outside by the
+flames, and also by the products of combustion, so that it forms a
+veritable heater of the currents which traverse it.
+
+The introduction of hot air into the central portion of the sheet of
+flame is advantageously supplemented by the spreading out of the flame
+by means of the metal disk, without any possibility of its being
+divided. In this way a more intense heat is obtained, and consequently
+the illuminating power is considerably increased, by the uncombined
+carbon being more readily set free, and being thus kept longer in the
+flame, F. This burner, which may be constructed for a moderate gas
+consumption, gives remarkable results as regards illuminating power
+and steadiness; the abstraction of heat in no way impairing the
+luminosity of the flame, which preserves all its brightness.
+
+The Argand burner with double chimney, shown in Fig. 7, is also an
+economical one for a small consumption of gas. The air admitted to
+both the inside and the outside is raised to a high temperature by
+passing along the spirals of a second and transparent chimney, C¹,
+which surrounds the cylindrical glass, C. The gas itself is heated by
+passing through this hot chamber before reaching the outlet orifices;
+so that the mixture of air and gas takes place under the most
+favorable conditions for their perfect combustion.
+
+The burner is an ordinary Argand, which may terminate below in a small
+chamber for the gas and air to mingle. But this is not necessary; and
+the usual arrangement for mixing the air and gas may be adopted. The
+outer air enters at the top of the central chimney, C and passes into
+the annular space between the two glasses; then descends by the two
+spiral passages, which surround the cylindrical glass and terminate
+in a portion hermetically sealed by a brass plate attached to the
+supply-pipe. All the parts of the burner are thus surrounded by a
+highly-heated atmosphere, especially at the bottom of the double
+chimney; and it will be readily understood that, if the branches which
+lead the gas to the burner are constructed of a highly conductive
+metal, the gas will become heated in its turn by passing through
+passages raised to a high temperature.
+
+The elements are therefore dissociated or separated before their final
+combination; thereby raising the calorific and luminous effect to the
+highest possible degree. Such a burner can, of course, be made as
+small as may be required; thus lending itself admirably to the
+subdivision of illumination. The only precaution required is to
+properly proportion the sectional area of the hot-air passages to the
+radiant surface of the flame, so that the heat does not become too
+intense at the lower portion of the burner.
+
+Fig. 8 shows a double flame burner on the principle of Mr. Heron's,
+but with admission of hot air into the angle formed by the flames. As
+exemplified by Mr. Heron, if two equal batswing burners separately
+give a certain amount of light, on the two flames being brought into
+contact, so as to form a single flame, the luminosity is considerably
+increased, owing to the condensation of heat which results from their
+meeting. The two incandescent sheets are, as it were, forced into one
+another, so as to be combined.
+
+[Illustration: FIG. 8. DOUBLE FLAT-FLAME BURNER]
+
+The high-power burners of Douglass, Coze, Mallet, and others were
+designed on this principle; but its application to uninclosed burners
+was not very satisfactory, because the great cooling down of the inner
+surface of the flames by the strong draught of cold air impaired their
+illuminating power. To counteract this difficulty, M. Somzee adopts a
+heating burner, A, which he places between the two batswing burners,
+B, so that the products of combustion rise in the angle made by the
+two lighting flames, as shown; thus greatly increasing their
+luminosity while maintaining a low consumption of gas.
+
+M. Somzee also raises the illuminating power of an ordinary flat-flame
+burner by causing an obscure effluvium to traverse the dark portion of
+the flame. The effect of this is to increase the activity of
+decomposition in this portion, so that the particles of carbon are the
+more readily set free, and remain longer in suspension in the luminous
+zone. The obscure effluvium may be determined between two points by
+the electric current, or be caused by the heating of an imperfect
+conductor by the current; or, again, it may result from a metal
+conductor heated by the reactions produced in the middle of the flame,
+by separating the cone of matter in ignition. The effect may be
+compared with that obtained by the concentration of two sheets of
+flame; but in this case the sheets are formed by the constituent parts
+of one and the same flame, whence results a more complete utilization
+of the elements composing it. This system is, in fact, a
+simplification of the arrangement adopted in the double-flame burner
+seen in Fig. 8.
+
+Fig. 9 shows a reflecting and regenerative burner with double glass.
+The crown, made of metal polished on both sides, has a circular
+groove, G, for receiving the end of the central chimney, C, and
+presenting an annular aperture by which the products of combustion
+enter. The second glass, C¹, is fastened to the collar of the
+burner carrier, and does not come into contact with the metal crown;
+so as to allow the air to enter from outside for supplying the burner.
+The gas enters by the pipe, T, provided with a cock. This pipe is
+continued to the top of the apparatus, and there spreads out into the
+form of a dome; thus dividing into two compartments the trunconic
+chamber, S¹ S squared, whence the hot gas returns to the body of the burner,
+B.
+
+[Illustration: FIG 9. REFLECTING AND REGENERATING BURNER.]
+
+On the burner being lighted from below, the products of combustion
+rise in the inner chimney, and enter the heater, which they traverse
+through its entire extent, while impinging against the outside of the
+gas reservoir, to which they give up a large portion of their heat.
+They then pass by the passage, D, into the atmosphere or into a
+chimney. The air necessary for combustion enters at the top of the
+outer globe, and becomes highly heated in its passage through the
+space comprised between the two glasses of the burner. In this way it
+reaches the burner, and forms an intimate mixture with the small jets
+of gas which compose the flame. The gas, on leaving the supply-pipe,
+T, fills one of the compartments, S¹ S squared, of the heater, and then
+returns by the second compartment, and again descends by the casing of
+the supply-pipe, having its temperature still further raised by
+contact with the internal radiation of the flame.
+
+Under these conditions, all the parts of the burner are supplied by
+heated air, and the combustion becomes very active; thus increasing
+the intensity of the flame, and consequently that of the light
+afforded, while at the same time effecting a saving of 50 per cent. of
+gas. This burner may be made of any size, and for consumptions not
+exceeding that of an ordinary Argand. In fact, the gas is consumed at
+a low pressure, escaping with no greater force than that due to the
+heat of the products of combustion. It is sufficiently expanded on
+coming into contact with the current of hot air, the activity of which
+is regulated by the height of the apparatus, that is to say, by that
+of its two chimneys. The mixture is made in such proportion as to
+obtain from the gas and air as great a degree of luminosity as
+possible. The high temperature of the gas, and the independent means
+of heating the air and gas, constitute the essential principles of
+this burner.--_Journal of Gas Lighting._
+
+       *       *       *       *       *
+
+
+
+
+THE CLAMOND GAS BURNER.
+
+
+[Illustration: THE CLAMOND GAS BURNER.]
+
+In this burner, which is a French invention, the light is produced by
+burning ordinary coal gas within a basket of magnesia, which is
+thereby brought to a high state of incandescence, and from which a
+white, steady light is radiated. It may be said to consist of three
+different parts. The first and inner part is a central column, B, of
+fireproof material. The second part consists of two concentric
+cylinders placed round the inner column and communicating one with the
+other through the cross cuts, J. The third part is a china cup
+inclosing the other parts, and perforated with a number of holes. The
+gas burns in two different places. From A it passes directly through
+B, at the top of which it branches off through tubes to an annular
+chamber, D, from which it escapes through the openings, _a_, _a_, _a_,
+where combustion takes place. The other combustion occurs within the
+circular space, G, I, between the column and the inner of the two
+surrounding cylinders, through two channels, E E, in the lower part of
+the central column. The gas passes into a circular chamber, F F, and
+escapes through small holes in the upper partition of this chamber,
+where it burns. The product of this combustion passes put into K,
+through the cross cuts, J. The air entering through the holes, H L, of
+the outer china cup passes along the inner of the two concentric
+cylinders, which is heated to redness, and rises highly heated toward
+the upper annular burner, where the gas burns at _a_, _a_, _a_, in small
+separate flames, each entirely surrounded by the hot air. This insures
+perfect combustion of the gas within the basket of magnesia placed
+above, and which is thus brought to a state of incandescence. It will
+be seen from this description how simple and practical the
+arrangement is. It is claimed for the light produced that it will
+stand comparison with the electric light. Like that, it shows colors
+perfectly true, and will enable an observer to distinguish between the
+most delicate shades, allowing of the finest work being executed as by
+daylight. It is, moreover, stated to be perfectly steady. As the
+Clamond burner can be fixed to any gas bracket or lamp now in use, its
+adoption causes no other expense than the cost of the burner itself.
+There is no expensive installation, and when used in combination with
+the electric light, it is claimed that a uniform lighting will be
+obtainable instead of the unpleasant contrast between gas and
+electricity. Another important advantage obtained by the Clamond
+burner is the saving effected in the consumption of gas as compared
+with the same power of light obtained from ordinary burners.
+
+       *       *       *       *       *
+
+
+
+
+A NEW THERMO-REGULATOR.
+
+
+In the thermo-regulators which have been constructed heretofore, the
+heat has been regulated by the variation in the inflow of gas to the
+heating flame. The apparatus described below, and shown in the
+accompanying cut, taken from the _Zeitschrift fur Instrumentenkunde_,
+operates on an entirely different principle. The distillation and
+condensation process of a fluid heated to the boiling point in the
+vessel, A, is as follows:
+
+[Illustration]
+
+The steam passes first through the pipes, _a_ and _c_, into the
+serpentine tube, where it is condensed, and then flows through the
+tubes, _d_ and _b_, back into the vessel, A, if the cock, _r_, is
+closed, but if the said cock is open, it flows into the receptacle, K.
+When the liquid begins to boil the steam passes freely through the
+tubes, _d_ and _b_, part passing through the tube, _f_, out into the
+air, and the other part passing through the open cock, _r_, to the
+receptacle, K; but the condensed liquid soon closes these passages to
+the steam. At _h_ is an opening for a thermometer, _t_, and through
+this opening the liquid can be poured into the vessel, A. If the cock,
+_r_, is kept closed, the volume of liquid in the vessel, A, cannot be
+diminished, and the bath, B, must take the constant and uniform
+temperature of the steam in the vessel, A, as the vessel, B, is heated
+evenly on all sides.
+
+This apparatus can also be used as an air bath, in which case the
+vessel, B, is left empty and closed by a suitable stopper.
+
+       *       *       *       *       *
+
+
+
+
+PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.
+
+
+The accompanying engraving represents a simple apparatus, which any
+person accustomed to working glass can make for himself, and which
+permits of quickly, and with close approximation, estimating the
+density of a liquid. In addition, it has the advantage of requiring
+but a very small quantity of the liquid.
+
+It consists simply of a straight pipette, A B, to which is affixed
+laterally, at the upper part, a small U-shaped water gauge.
+
+The two branches of the gauge, as well as the pipette itself, are
+graduated into equal divisions. If need be, the graduating may be done
+by simply pasting on the glass strips of paper, upon which a graduated
+scale has been drawn. The zero of the pipette's graduation is exactly
+at the lower extremity, B. The graduation of the two gauge tubes
+extends in both directions from a zero situated near the center. The
+zeros of the two branches must correspond as exactly as possible, so
+that they shall be in the same horizontal plane when the apparatus is
+fixed upon a support. To render the apparatus complete, it only
+remains to adapt, at A, a rubber tube provided with a wire clamp, and
+terminating in a short glass tube for sucking through with the mouth.
+
+[Illustration: PIPETTE FOR TAKING THE DENSITY OF LIQUIDS.]
+
+For taking the density of a liquid, we plunge the end, B, into it, and
+then suck, and afterward close the rubber tube with the clamp. It is
+essential that this latter shall hold well, so that the levels may
+remain constant.
+
+We now do the reading. Suppose, for example, we read 250.3 mm. on the
+pipette, and 147.7 mm. and 152 mm. on the branches of the gauge.
+Having these data, we loosen the clamp, and allow the liquid to flow.
+On account of capillarity, there remains a drop in B; and of this we
+read the height, say 6 mm. A height 250.5 mm - 6 = 244.5 mm. of liquid
+raised is, then, balanced by a column of water of 147.5 + 152 = 299
+mm.
+
+Now the heights of these two liquids is in the inverse ratio of their
+densities:
+
+  _d_   299.5
+  --- = -----, whence _d_ = 1.22.
+   1    244.5
+
+We obtain _d_ by a simple division.
+
+When the instrument has been carefully graduated, and has been
+constructed by an expert, the accuracy of the first two decimals may
+be relied upon. With a little practice in estimating the last drop, we
+may, in trying to estimate the density of water, even reach a closer
+approximation. In order to measure the height of the drop accurately,
+one should read the maximum height to which the liquid rises between
+the fall of two drops at the moment when the last ones are falling,
+since at that moment, and only at that, can it be ascertained that the
+lower level of the bubble is plane. The error in such reading does not
+reach half a millimeter, and, as a suitable height of the apparatus
+permits of having columns that vary between 13 and 30 centimeters, an
+error of this kind is but 1-300. This is the limit of precision of the
+method.
+
+The clamp might be advantageously replaced by a glass cock, or, better
+still, A might terminate in a rubber bulb; and a lateral tubulure
+might be fixed to the pipette, and be closed with a rubber stopper.
+
+This little apparatus is more easily maneuvered than any of those that
+have hitherto been devised upon the same principle. It is capable also
+of replacing areometers in ordinary determinations, since it permits
+of correcting the error in capillarity that is neglected in
+instruments; and, moreover, one can, when he desires to, easily verify
+for himself the accuracy of the graduation.--_La Nature._
+
+       *       *       *       *       *
+
+
+
+
+USEFUL BAGS, AND HOW TO MAKE THEM.
+
+By JOHN T. HUMPHREY.
+
+
+Since the papers on "Boot and Shoemaking," in vol. i. of _Amateur
+Work_, illustrated, I think nothing relating to the leather trades has
+appeared in it; and as there must be many among the readers of this
+magazine who have a desire to dive deeper into the art of manipulating
+leather into the various articles of utility made from that material,
+I will endeavor in the series of articles of which this is the
+commencement to furnish them with the necessary instructions which
+will enable them to do for themselves many things which now are left
+undone, or else have to be conveyed miles to some town where the
+particular business, or something akin to it, is carried on. To the
+colonist and those who live in out-of-the-way districts, it must be a
+matter of great regret to observe articles of use, where the material
+is in good condition, rapidly becoming useless owing to the inability
+of the possessor to do the necessary repairs. Again, it may be that
+the article is completely worn out, and the old proverb that "a stitch
+in time saves nine," will not be advantageously applied if carried
+out. In that case a knowledge of making new what we require, whether
+in order to replace something already worn out or as an addition to
+our store, must prove beneficial to the thrifty amateur. My object in
+writing these articles is not to deprive the mechanic of any portion
+of his legitimate occupation, but to assist those who live at a
+distance too great to be able to employ him, and who necessarily
+prefer any makeshift to the inconvenience of sending miles, and being
+without for days, an article which might possibly be set right in an
+hour or two.
+
+
+HOW TO MAKE BAGS.
+
+The old-fashioned carpet bag (Fig. 1) is still unsurpassed by any,
+where rough wear is the principal thing to be studied. Such a bag, if
+constructed of good Brussels carpeting and unquestionable workmanship,
+will last a lifetime, provided always that a substantial frame is
+used.
+
+[Illustration: FIG 1.--THE CARPET BAG.]
+
+Next in order comes the brief bag (Fig. 2), more extensively used than
+any other. For business purposes it is in great favor with bag users,
+being made in a variety of shapes, but all belonging to the same
+class. Here we have the shallow brief, deep brief, eclipse wide mouth,
+imperial wide mouth, excelsior, courier, and many others; but to know
+how to make one will be sufficient for all, the only difference being
+in the cut or style in which they are constructed.
+
+[Illustration: FIG. 2.--THE BRIEF BAG.]
+
+The cricket bat bag (represented in Fig. 3) is made on the same
+principle throughout as the carpet bag.
+
+[Illustration: FIG. 3.--THE CRICKET BAT BAG.]
+
+Frames and all necessary fittings required in making bags may be
+purchased of dealers.
+
+Care must be observed in choosing all the pieces necessary for a bag
+from the same pattern carpet, otherwise it will present an unsightly
+appearance when completed. There may be some who would prefer American
+cloth; this is thoroughly waterproof, and has a good appearance for
+some time, but, like all articles of imitation, it has only
+_cheapness_ to recommend it. If cloth is to be used (I mean American
+cloth), let it be the best that can be bought, that which is called
+"double-twill duck," if possible. As the making is the same whether
+cloth or carpet be used, it will be understood that the instructions
+for making apply to both.
+
+The following tools, which are few and inexpensive, will be required:
+A pair of clams (Fig. 4), cost 1s. 6d.; knife (Fig. 5), 6d.; half
+dozen awl blades, 1/2d. each; three or four boxwood handles, 11/2d. each;
+3 foot rule, 1s.; hammer, 1s.; a packet of harness needles, size 4,
+cost 21/2d. (these have blunt points); a bone (Fig. 6) will also be
+required for rubbing the stiffening into place, cost about 3d.; and a
+ball each of hemp and wax for making the sewing threads--hemp 21/2d.,
+wax 1/2d. For making holes in the bottom where the nails or studs are
+fixed, a large sewing-awl will be required; this will probably have to
+be bought at a saddler's; the other tools can all be obtained at any
+grindery and leather seller's.
+
+[Illustration: FIG. 4--Pair of Clams. FIG. 5--Knife. FIG. 6--Bone
+Rubber. FIG. 7--Method of Measuring Registered Frame: A to A, Top of
+Sides; A to B, Top of Gussets. FIG. 8--Pattern of Bottom, Showing
+Place of Nails. FIG. 9--Side Pattern Folded. FIG. 10--Gusset Pattern
+Folded. FIG. 11--Pattern for Gusset Stiffening. FIG. 12--Handle,
+Showing Distance of Rings.]
+
+The awl blades mentioned above are of two kinds, and either may be
+used for this work. Those generally used are of a straight diagonal
+shape, making a perforation the shape of a diamond, <>*; the others are
+perfectly round, tapering gradually to a fine point. To fix them in
+the boxwood handles, place the blade in a vise, leaving the unpolished
+part above the jaws; hold the handle above this, and commence driving
+it down, taking care that the blade is penetrating the middle of the
+handle. Continue tapping the handle until the ferrule reaches the
+polished part of the blade; it will then be in far enough.
+
+  * Transcriber's Note: Original diamond vertical instead of horizontal.
+
+A good serviceable pair of clams may be made by taking two staves of a
+good-sized barrel, and cutting about 10 inches off the end of each.
+Screw together with three screws (as in Fig. 4), and shape the
+uppermost ends so that the outsides meet in a sharp ridge along the
+top; this will give a flat surface within the mouth, by which a hold
+of the work may be obtained. A two-inch screw will be long enough for
+the bottom, which must be turned in as tightly as possible; the others
+must not be less than 3 inches, as there will be a space of 11/2 or two
+inches between the staves at the part where they are inserted. Screw
+these just tight enough to give a good sharp spring to the mouth of
+the clams when they are pressed open; this will insure the work being
+held firmly while being sewn. Sandpaper them over to give a smooth
+appearance, and these will be found as useful as bought ones.
+
+A piece of basil leather will be required for the bottom and welts of
+the bag. This may be purchased at a leather seller's with the tools.
+Cut out the bottom first; the welts may be cut from any narrow pieces.
+These must be cut seven-eighths of an inch wide, then folded over, and
+lightly hammered down. This brings the two edges together, and when
+placed in position, they should lie evenly between the edges of the
+material. A piece of string may be laid in the welt to give it a
+fuller appearance if the leather is very thin.
+
+The following dimensions of bags when made up will enable the maker to
+choose the most useful size:
+
+  No. 1, 16 by 14 inches; No. 2, 19 by 16 inches;
+  No. 3, 21 by 17 inches; No. 4, 24 by 18 inches.
+
+The sizes of frames and parts when cut will be as follows:
+
+          Frame.      Sides.     Bottom.    Gussets.
+
+  No. 1, 15 inches  161/2 by 151/2  161/2 by 51/2  151/2 by 51/2
+  No. 2, 18 inches  191/2 by 171/2  191/2 by 6   17  by 6
+  No. 3, 20 inches  211/2 by 181/2  211/2 by 61/2  181/2 by 61/2
+  No. 4, 23 inches  241/2 by 191/2  241/2 by 61/2  191/2 by 61/2
+
+Taking No. 1, 161/2 inches will be the length of sides and 151/2 inches
+the depth. The gussets are also 151/2 deep, the width being 51/2, the same
+as the bottom. Take 11/2 inches from the depth of these to allow for
+covering the frame, and 1/2 inch from the length to allow for the seams,
+and we have a bag 16 inches long by 14 inches deep.
+
+And now to commence. Arrange the pieces of carpet on the board, and
+mark off the size of each part required with a piece of chalk or
+pipeclay. By cutting with the carpet, laying the right side up, we
+shall be able to see that the pattern of it will be in the same
+direction on both sides of the bag when made up. We next take the ball
+of hemp, and by pushing the finger through the hole in the center of
+it, drive out the end. To use the hemp from the inside is much the
+best way, because the ball will stand perfectly still, whereas, if
+started from the outside, it will be darting in all directions about
+the floor of the workroom, and entwining itself around any obstacle
+which lies there, unless it is placed securely in a box and drawn out
+through a hole in the center of lid.
+
+A hook must be fixed in some convenient place to make the waxends on,
+or, as they are called in the trade, "threads," which term it will be
+as well to call them by here; thus a _four-cord thread_ means a thread
+or waxend containing four strands of hemp, a six-cord contains six
+strands, and so on. One of the greatest difficulties for the amateur
+is to produce a well-formed thread. He generally finds it thicker a
+few inches from the point than at any other part. These are known in
+the trade as bull-necked threads; and as the mechanic finds it
+difficult to use them when his employer starts a new apprentice and
+gives him this job for the men, I must impress on the worker here the
+necessity of making them as perfect as possible. It would be as well
+if a little practice was given at breaking the hemp in the way which
+produces good points. Better waste a few yards of hemp than be
+compelled to abandon a thread after making only a few stitches with
+it.
+
+Gripe the hemp firmly between the thumb and forefinger of the left
+hand, leaving about eight or nine inches hanging loosely down; lay
+this over the thigh of the right leg, and with the right hand rub it
+in a downward direction, which will cause the twisted strand to
+loosen. One good stroke should be sufficient; if not, it must be
+repeated until the fibers forming the strand are quite loosened. By
+holding it close to the end with the right hand, and giving it a jerk
+with the left, the fibers will break, and the ends of the strands
+formed in this way are placed at a little distance one above another,
+which, when twisted, form a smooth, tapering point.
+
+To cast off a thread the proper way is to stand at a distance of about
+three feet from the hook previously mentioned, and by holding the end
+of the hemp in the left hand, pass it over the hook and bring it down
+with the right, then holding with the left and breaking as above. When
+sufficient strands to form the thread have been broken off, carefully
+examine the points to see that they taper properly, and have no lumps
+in them. Rub the wax up and down a few times, so that the thread may
+be properly waxed on that portion which will be inside when twisted.
+Hold the two ends in the left hand, and with the right roll each end
+separately down the right leg a sufficient number of times to twist
+the thread throughout. Judgment will be required in this operation, or
+the thread will be a constant source of trouble if it is over-twisted.
+Wax it again, and then it is ready for use. See that the points are
+well waxed, then take a needle and pass the point of the thread
+through the eye until it nearly reaches that part which would stop its
+progress.
+
+It must now be turned down on to the thicker portion and carefully
+twisted. Smooth it down, then take the other end of thread and another
+needle, and fasten it on in the same way. In selecting the awl to be
+used, do not take a very large one. The hole should be just large
+enough for the thread to require a slight pull to get it through.
+
+To commence sewing take one side and a gusset and place them evenly
+together, the right side of the material being inside, and fix them in
+the clams. Slip the welt as previously described between the edges,
+and pass the awl through the lot. Drive it perfectly straight, as upon
+this chiefly depends a nice seam when turned. Draw out the awl, and by
+following the point, pass up the bottom needle with the left hand.
+This should be taken by the thumb and forefinger of the right hand and
+the thread pulled through half its length, so forming a thread of
+equal length on each side. Make another hole with the awl about
+one-third of an inch from the first. This gives the length of stitch.
+Pass up the bottom needle as before into the right hand, the top
+needle descending to the bottom immediately after. Take hold of this
+with the left hand and pull through the threads simultaneously top and
+bottom, until the extremity on each side lies on and forms the stitch.
+Be careful that in pulling in the latter part each thread closes at
+the same time, thereby preventing a crooked seam. Repeat until the
+seam is finished, then take the other gusset and place in position.
+Sew this, then take the other side of bag and sew to the gussets. You
+will then have something in the shape of a bag, minus the bottom. Take
+this next, and fix each corner to one of the seams previously made,
+and stitch it carefully round, placing a welt in as before. At the end
+of each seam a stitch or two back should be taken or the thread tied
+over to prevent it opening.
+
+The outside of the bag being inward, it must now be turned previous to
+stiffening and framing. The turning is done by placing the bag over
+the left arm, and with the right hand commence pushing in one of the
+corners, then the opposite one until that end is reversed. Then serve
+the other end in a similar manner, and smooth each seam along.
+
+We now take a piece of stout millboard (an old ledger book cover will
+do if large enough), or, if purchased with the frame, ask for a two
+pound board: this will cost about 4d., and be sufficient for several
+bags. Cut it quarter of an inch less than the bottom all round, and
+see that it fits before gluing it in. To do this, place one end within
+the seams at one end of the bag, and by lifting it in the middle press
+in the other, when the stiffening will lie within the four seams at
+the bottom. Having fitted it satisfactorily, take it out again and
+glue it well with some good hot glue. This must be neither too thick
+nor too thin. The best way to prepare it is to lay some glue in cold
+water for twelve hours. It will absorb sufficient water in that time,
+and can be boiled up without any further preparation. The quicker it
+is fixed after the glue is put on the better. A brush similar to a
+paint brush will be the best to apply it with, and need not cost more
+than 6d. After the gluing, lay it aside for a few hours to allow it to
+thoroughly set, during which time the making of the handles can be
+proceeded with. On some bought bags these are very common, and seldom
+last more than a few months; the usual plan being to take a piece of
+rope about the size of a clothes line and roll a piece of brown paper
+round it, covering it afterward with a piece of basil leather.
+
+Procure two pieces of brown harness leather--the shoulder of the hide
+is most suitable--from a saddler, 11 inches long by 1-1/8 inches wide,
+round the four ends, and make a compass mark 1/8 of an inch from the
+edge all round for the stitching. Take a piece of line as above, and
+place within the leather, which most likely will have to be damped to
+make it draw round easier. Leave 11/2 inches from each end for sewing to
+the bag, the line also being so much less than the full length of the
+handles. Having sewn them, flatten the ends and bend the handles into
+a semicircular shape, and leave them to dry.
+
+By this time the glue holding the stiffening to the bottom of the bag
+will be set, so the next move will be to put in the studs or nails.
+Take the largest size awl and make five punctures through the bottom,
+about three-quarters of an inch from each corner and one in the
+center, as in Fig 8; push the nails through and turn down each of the
+two claws in an opposite direction, tap them with a hammer to make
+them lie closer, and also to prevent them from becoming loose. This
+done, we next take the frame and remove the key-plate from it.
+
+Fold the sides of the bag well over the frame, so that the stitching
+will get a good hold of the part that goes inside. Put a stitch
+through at each corner to hold it, and see that it sets perfectly true
+on the frame. A space is left between the two plates of iron forming
+the frame, which allows of the bag being sewn through it. Fix the
+key-plate by riveting inside. Sew the bag from one corner of frame to
+the other corner on each side, leaving the gussets unstitched. It is
+now ready for the lining. Let this be good, as it will greatly add to
+the durability of the bag if strong. Coarse linen at 8d. to 10d. per
+yard is the best material for this purpose. The sides and bottom may
+be cut in one piece; the length of this will be twice the depth of one
+side of carpet (less the part which folds over the frame) and the
+width of the bottom. The width of this piece throughout to be a half
+inch less than the outsides were cut. The gusset lining will want to
+be the same width as the gusset, but an inch less in length will do.
+The seams of the lining may be stitched with an ordinary household
+sewing machine if good thread is used. When made, place the lining
+inside the bag, see that it is well down at the bottom, turn in the
+top edge all round to the required size, and fix in as follows: Take a
+long carpet needle and a length of thread, pass the needle through the
+lining at the folded ridge and bring it up again through the same at a
+distance of an inch or so. This forms a stitch within the lining; pass
+the needle through one of the stitches made in sewing in the frame and
+repeat as before, carefully observing that the lining falls into its
+proper place as it is being sewn in. Continue in this way until the
+two sides are done, leaving only the gussets and gusset lining to be
+united. This is done by folding the edges inward and sewing them
+together, the frame joints moving freely between the gussets and
+lining. We have now only the handles to put on and it is complete. Sew
+these on with a five cord thread well waxed. To protect the lock
+against being unduly strained when filled, a strap and buckle may be
+put on between the handles and each end of the frame, as in Fig. 3.
+
+Next in order is the cricket bat bag, which should always be comprised
+in the outfit of the amateur cricketer, as well as of the
+professional. In making this we follow the instructions given for the
+carpet bag. It may be made either of carpet, tan-canvas, or leather,
+the latter, of course, being the strongest and most expensive. Carpet
+will not require to be described, but a brief description of
+tan-canvas and leather may be of service to the amateur in assisting
+him to choose something for himself.
+
+Tan-canvas, as used for bags and portmanteaux, is a strong, coarse
+material of a brown color; it wears well, and has one advantage over
+carpet--it is thoroughly waterproof.
+
+Leather is, of course, superior to carpet or canvas, but there are a
+few tricks in its manufacture which it may not be out of place here to
+mention as a caution to the amateur that the old saying, "There's
+nothing _like_ leather," is a thing of the past where the general
+appearance of an article is meant. The genius of the inventor has
+produced machinery which gives to paper, linen, and other stuffs the
+appearance of the genuine article, whereas it does not contain one
+particle of it. At one time, when a hide of leather was required to be
+of the same thickness all over it, the currier would work at the flesh
+of the skin with a shaving knife, gradually scraping the thick parts
+away until it was reduced to the required substance. Now it is done
+in a few minutes. The hide is passed whole between the rollers of a
+splitting machine against the sharp edge of a knife, which reaches
+from one side of the machine to the other, a distance of 10 or 12
+feet. This knife is so gauged that any thickness can be taken off at
+one operation, the part taken off resembling the hide in size and
+shape. The top or grain of the hide is then dressed and finished off
+brown, if for brown hides; or, if to be used for enameled hides, they
+are dyed and japanned. These are called either brown or enameled
+cow-hides, according as they are finished off, and are used for all
+the best class of Gladstone, brief, and other bags. The bottom or
+fleshing of the hide is also dyed and japanned, and when finished,
+exactly resembles in appearance the hide itself, and is very difficult
+for the novice to tell when made up into bags or any other article.
+These are called _splits_, and having had the best part of the skin
+taken from them, do not wear one-fourth the time the grain will. The
+black enamel soon chips off, which gives them a worn-out appearance.
+
+To make a bag 36 inches by 12 inches by 8 inches requires a frame 36
+inches long, the sides 361/2 inches by 14 inches, gussets 14 inches by
+81/2 inches, bottom 361/2 inches by 8 inches. The lining will be 36 inches
+by 12 inches for the sides, gussets 13 inches by 8 inches, bottom 36
+inches by 8 inches. For the handles two pieces of leather 12 inches by
+2 inches. The straps and chapes are sewn on quite close to the frame,
+straps 10 inches long by 1 inch, chapes 41/2 inches by 1 inch. Cut a
+slit in the middle of the chape for the buckle tongue to go through,
+and pare the under side at the end so that it is not too lumpy when
+sewn on to the bag. Cut two loops 3 inches long by 3/4 inch wide for the
+points of straps to go through.
+
+The brief bag must be made of leather, and as there is the same amount
+of work in making it, whether it be of split or hide, it will be sure
+to give greater satisfaction if the latter is chosen. The manufacture
+of this bag differs considerably from the others. The sides and
+gussets in the carpet bag are cut straight from top to bottom, but in
+the brief bag they must be shaped to fit the frame, and give it a more
+comely appearance. The frame, as before described, is quite different.
+The way to commence with this bag is to open the frame as in Fig. 7,
+so that it will lie perfectly flat upon the bench. With the rule
+measure it carefully between the corners, A, A, and again at A, B. The
+distance between A and B being less when the frame is open than when
+closed, an additional 1/2 inch must be added to allow the gusset to bend
+freely round the hinge. Having correctly taken these measurements, get
+a sheet of brown paper and fold it in the middle; the reason for this
+is to allow of each side of the pattern taking the same curve at the
+swelled part. Cut the pattern for the sides first by ascertaining half
+the distance, A, A, and marking it on to the edge of the paper,
+measuring from the folded edge toward the ends. Next mark on the
+folded edge the depth you intend the bag to be, allowing in this, as
+in the carpet bag, 11/2 inches for covering the frame. The depths of
+brief bags vary so much that I will give these only as a guide,
+leaving my readers to add or reduce as their fancy guides them; but if
+they should strictly adhere to these given below, I am certain they
+will find them very useful sizes.
+
+For a 12 inch frame cut the sides and gussets 101/2 inches in depth;
+when made up, these will be 9 inches from the frame to the bottom. For
+a 14 inch frame add 1 inch, and for a 16 inch add 2 inches. This will
+make these 10 inches and 11 inches in depth respectively when made up,
+and either of these will be found a very useful bag for many purposes.
+The width of the bottoms to be cut 5 inches, 51/2 inches, and 6 inches,
+the 5 inch, of course, for the 12 inch bag, the 51/2 inch for the 14
+inch, and the 6 inch for the 16 inch. The depth having been decided
+upon, and marked on the folded edge of the paper, make another mark
+the same distance from the edge at the first mark, H. The bottom of
+the sides being 1 inch longer than the top, add 1/2 inch to the
+measurement of the top of pattern when the bottom part is marked off
+at J L. Draw a curved line between H L, as in Fig. 9, and cut through
+the two thicknesses of paper at one time, keeping them well together
+to insure them being alike. The gusset pattern may be cut in the same
+way, D to D, Fig. 10, being half the distance of A B, Fig. 7, and the
+1/2 inch added for going round the joint; E E, the swelled part, which
+bends into the bag when the frame is closed, and also allows it to
+open perfectly square; F F is half the width of the bottom of gusset.
+A pattern for the bottom of the bag may be made by folding a piece of
+paper each way to get the length and width; make a small hole through
+the four thicknesses, open it and mark it from hole to hole, using the
+rule as a guide. This will be found to be perfectly accurate.
+
+To cut out the bag, lay the leather on the bench, enameled side
+downward, and see that the patterns lie on it so the creases will run
+from the top to bottom of the bag when made. The sides must be taken
+first, and as they are more exposed than any other part, they should
+be taken from the best part of the hide. Take the gussets next, then
+the bottom. The welts are taken from the cuttings which are left. To
+make the handle, glue a lot of odd pieces together about 61/2 inches
+long, 1/2 inch wide, and the same thickness, and when dry pare the edges
+away until it is perfectly round and slightly tapering toward each
+end. It is then divided and glued top and bottom to a strip of good
+leather cut to shape, Fig. 12, which is passed through the rings at
+each end, and turned back to form a shape. Put a few stitches through
+close to the rings before the fittings are glued on, and cover with a
+piece of cow-hide long enough to go through the two rings and along
+the under side, then stitch it. Trim and dye the edges, rubbing them
+afterward with a piece of cloth to produce a polish. Before making the
+handle, the plates must be on the rings, or it will prove a difficult
+job to get them on afterward.
+
+The stiffening for the bottom will be cut as if for a carpet bag. Fig.
+11 represents the stiffening for the gussets, and is cut from a board
+half the thickness of that used for the bottom.
+
+The linings may be cut from the outside patterns by reducing them the
+11/2 inches, allowed for covering the frame, and 1/8 inch for each welt.
+A lining of scarlet or blue roan greatly adds to the appearance and
+durability of a bag. A skin large enough for a 14 inch or 16 inch will
+cost about 3s.
+
+Cow-hide for the outside is sold at 1s. 8d. per square foot, but the
+leather sellers frequently have pieces large enough for making a bag
+which they will sell at a slight reduction, and which answers this
+purpose as well as cutting a hide. In seaming the bag, take care not
+to wrinkle it in the clams. The welts in this must reach only to the
+frame, the same as in the carpet bag; the rest of the seam must be
+neatly closed and rubbed down, so that it will not be lumpy on the
+frame. Before turning the bag warm it before the fire, especially if
+it is cold weather. Glue in the bottom stiffening first, and then the
+gussets, rubbing them well down with the bone. When these are set,
+prepare for the operation of framing. Fold one of the sides to get the
+middle of it, cut a hole for the lock barrel about 11/4 inches from the
+edge, and press it over. Be careful not to cut it too large or the
+hole will show. Pierce a hole through the leather for the lock plate,
+press this tightly on the frame, and clinch the clams underneath, to
+hold it securely. Make holes for the handle plates and fasten them on
+in a similar manner. Two slits must be cut near the middle of the
+other side of bag, about 3/4 inch from the edge, for the hasp to go
+through. This bag must be sewn to the frame all round, and care must
+be taken that a sufficient fullness is allowed in the middle of the
+gusset to enable it to close easily round the joints of the frame. A
+thumbpiece must be sewn on the bag at the hasp to open it by. The
+lining of this bag is sewn through the frame all round in the same
+manner as the side linings of the carpet bag.
+
+I hope my readers will not think that I have gone too much into
+details. It is in small things that so many failures take place. As it
+is much easier to do anything when you are shown than when so much has
+to be guessed, it is my desire to make the road for beginners as
+smooth as possible, which must be my excuse if any is required. It is
+as well that those who intend to turn their attention to working in
+leather should begin by making a bag; the experience gained in
+cutting, fitting, putting together, and finishing will be useful when
+larger and more difficult pieces of work are undertaken.--_Amateur
+Mechanics._
+
+       *       *       *       *       *
+
+
+
+
+MOLASSES, HOW MADE.
+
+
+The _New England Grocer_ says that the manufacture of molasses is
+really the manufacture of sugar up to a certain stage, for molasses is
+the uncrystallized sirup produced in the making of sugar. The methods
+of manufacture in the West Indies vary very considerably. In the
+interior and on the smaller plantations it is made by a very primitive
+process, while on the larger plantations all the appliances of modern
+science and ingenuity are brought to bear. Each planter makes his own
+sugar. It is then carried to the sea coast and sold to the exporters,
+by whom it is shipped to this country. The quality and grade of the
+molasses varies with each plantation. Two plantations side by side may
+produce entirely different grades. This is owing to the soil, which in
+Porto Rico and other localities in the West Indies seems to change
+with almost every acre. The cane from which the sugar and molasses is
+made is planted by laying several pieces of it in holes or trenches.
+The pieces are then covered with earth to the depth of two or three
+inches. In about two weeks sprouts appear above the surface. Then more
+earth is put in, and as the sprouts grow, earth is added until in
+three or four months the holes are filled up. The planting is done
+from August to November, and the cutting progresses throughout the
+greater part of the year. The cane grows to a height of seven or eight
+feet, in joints each about a foot long.
+
+When the cane is in proper condition for cutting, as shown by its
+appearance, an army of workmen take possession of the field. Each is
+armed with a long, broad knife, like a butcher's cleaver. They move
+down the lines of cane like an army, and while the cutting is going on
+the fields present an interesting sight, the sword-like knives
+flashing in the sun, the 300 or 400 laborers, the carpet of cut cane,
+the long line of moving carts, and the sea of standing cane, sometimes
+extending for miles and miles, stirred by the breeze into waves of
+undulating green. The laborers employed on these plantations are
+largely negroes and Chinese coolies. When the cane is ripe, they
+proceed to the field, each armed with a _matchet_. Spreading over the
+plantation, they commence the cutting of the cane, first by one cut at
+the top, which takes off the long leaves and that part which is
+worthless, except as fodder for the cattle. A second cut is then given
+as near the root as possible, as the nearer the ground the richer the
+cane is in juice. The cut cane is allowed to fall carelessly to the
+ground.
+
+Other workmen come with carts, pick it up, tie it in bundles and
+carry it to the mill. The cutting of the cane is so adjusted as to
+keep pace with the action of the mill, so that both are always at
+work. Two gangs of men are frequently employed, and work goes on far
+into the night during the season, which lasts the greater part of the
+year.
+
+As before stated, some of the methods of manufacture are very simple.
+In the simplest form, the sugar cane is crushed in a mortar. The juice
+thus extracted is boiled in common open pans. After boiling a certain
+length of time, it becomes a dark colored, soft, viscid mass. The
+uncrystallized sirup is expressed by putting the whole into cloth bags
+and subjecting them to pressure. This is molasses in a crude state. It
+is further purified by reboiling it with an addition of an alkaline
+solution and a quantity of milk. When this has continued until scum no
+longer arises, it is evaporated and then transferred to earthen jars.
+After it has been left for a few days to granulate, holes in the
+bottom of the jars are unstopped, and the molasses drains off into
+vessels placed to receive it. Another process of extracting molasses
+is as follows: By various processes of boiling and straining, the
+juice is brought to a state where it is a soft mass of crystals,
+embedded in a thick, but uncrystallized, fluid. The separation of this
+fluid is the next process, and is perfected in the curing house, so
+called. This is a large building, with a cellar which forms the
+molasses reservoir. Over this reservoir is an open framework of
+joists, upon which stands a number of empty potting casks. Each of
+these has eight or ten holes bored through the bottom, and in each
+hole is placed the stalk of a plantain leaf. The soft, concrete mass
+of sugar is removed from the cooling pans in which it has been brought
+from the boilers and placed in the casks. The molasses then gradually
+drains from the crystallized portion into the reservoir below,
+percolating through the spongy plantain stalks.
+
+On the larger plantations, machinery of very elaborate description is
+used, and the most advanced processes known to science are employed in
+the manufacture. The principle is, however, the same as has been seen
+in the account of the simpler processes. On these larger plantations
+there are extensive buildings, quarters for workmen, steam engines,
+and all the necessary adjuncts of advanced manufacturing science. In
+the sugar mills the cut cane is carried in carts to the mill. It is
+then thrown by hand upon an endless flexible conductor which carries
+the cane between heavy crushers. The great jaws of the crushers press
+the cane into pulp, when it is thrown aside automatically to be carted
+away and used as a fertilizer. The juice runs off in the channels of
+the conductor into huge pans. The juice is now of a dull gray color
+and of a sweet, pleasant taste, and is known as _guarapo_. It must be
+clarified at once, for it is of so fermentable a nature that in the
+climate of Porto Rico it will run into fermentation inside of half an
+hour if the process of clarifying is not commenced. The pans into
+which the juice is conducted are pierced like a colander. The liquor
+runs through, leaving the refuse matter behind. It is then forced into
+tanks by a pump and run to the clarifiers, which are large kettles
+heated by steam. Lime is used to assist the clarification. It is then
+filtered into vats filled with bone black. The filtering is repeated
+until the juice changes color, when it is conveyed to the vacuum pans.
+It has now become a thick sirup. It is then pumped into the sirup
+clarifiers, skimmed, and again run through bone black, and finally is
+conducted into another kettle, where it is allowed to crystallize. The
+sirup that fails to crystallize is molasses, and it is here that we
+catch up with what we started after. To extract the molasses from the
+crystallized mass of sugar, we must go to the purging house. This is
+similar to the building spoken of in connection with the simpler
+process. It is of two stories. The upper floor is merely a series of
+strong frames with apertures for funnel-shaped cylinders. The sugar is
+brought into the purging house in great pans, which are placed over
+the funnels. The pans are pierced with holes through which the
+molasses drains off into troughs which are underneath the floor, all
+running to a main trough. From thence the molasses runs into vats,
+called _bocoyes_, each of which holds from 1,200 to 1,500 gallons. The
+hogsheads in which the molasses is brought to this country are
+manufactured principally in Philadelphia and taken to the West Indies.
+They are placed in the hold of the vessel and the molasses pumped into
+them. The government standard for molasses is 56 degrees polarization.
+When not above that test, the duty is four cents per gallon. Above it
+the duty is eight cents. This tends to keep molasses pure, as the
+addition of glucose increases the quantity of sugar and therefore of
+the polarization, and would make necessary the payment of increased
+duties. The adulteration of molasses is therefore largely if not
+wholly done after it is out of bond and in the hands of the jobber.
+
+       *       *       *       *       *
+
+
+
+
+PRIMITIVE IRON MANUFACTURE.
+
+
+We are indebted for the illustrations and the particulars to Dr.
+Percy's invaluable book on iron and steel (probably it is not saying
+too much to describe it as the best work on the subject ever written).
+
+[Illustration: SECTION OF INDIAN BLAST FURNACE AND BLOWING MACHINE.]
+
+Fig. 1 shows a sectional elevation, and Fig. 2 shows a plan of furnace
+and bellows and tuyeres, indeed, an entire ironworks plant used in
+India, not only now, but, so far as we can gather, from time
+immemorial. The two figures give a sufficiently clear idea of the form
+of furnace used in Lower Bengal, in which portion of our Indian empire
+there are entire villages exclusively inhabited by iron smelters, who,
+sad to relate, are distinguished from the agricultural villages
+surrounding them by their filth, poverty, and generally degraded
+condition. There are whole tribes in India who have no other
+occupation than iron smelting. They, of course, sink no shafts and
+open no mines, and are not permanent in any place. They simply remain
+in one place so long as plentiful supplies of ore and wood are
+obtainable in the immediate vicinity. In many cases the villages
+formerly inhabited by them have passed out of existence, but the
+waste, or rather wasted products, of their operations remain.
+
+The furnace shown in Figs. 1 and 2 is built of the sandy soil of the
+district, moistened and kneaded and generally strengthened by a sort
+of skeleton of strips of flexible wood. In form it varies from a
+cylinder, more or less circular, diverging into a tolerably acute
+cone, the walls being about 3 in. thick. The height is generally
+about 3 ft. and the mean internal diameter about 1 ft., but all these
+dimensions vary with different workmen and in different localities.
+There are two apertures at the base of the furnace; one in front,
+about 1 ft. in height, and rather less in width than the internal
+diameter of the furnace, through which, when the smelting of one
+charge is finished, the resulting mass of spongy iron is extracted,
+and which during the smelting is well plastered up, the small conical
+tuyere being inserted at the bottom. This tuyere is usually made of
+the same material as the furnace--namely, of a sandy soil; worked by
+hand into the required form and sun-dried; but sometimes no other
+tuyere is employed than a lump of moist clay with a hole in it, into
+which the bamboo pipes communicating with the bellows are inserted.
+The other aperture is smaller, and placed at one side of the furnace,
+and chiefly below the ground, forming a communication between the
+bottom of the furnace chamber and a small trench into which the slag
+flows and filters out through a small pile of charcoal. It is this
+slag being found in places where iron is not now made that shows that
+iron smelting was an occupation there, perhaps many centuries before.
+
+The inclined tray shown at the top of the furnace on Fig. 1 is made of
+the same material as the furnace itself, and when kneaded into shape
+is supported on a wooden framework. On it is piled a supply of
+charcoal, which is raked into the furnace when required.
+
+The blowing apparatus is singularly ingenious, and is certainly as
+economical of manual labor as a blowing arrangement depending on
+manual labor well can be. A section of the bellows forms the portion
+to the right of Fig. 1, showing tuyere forming the connection between
+bellows and furnace. It consists of a circular segment of hard wood,
+rudely hollowed, and having a piece of buffalo hide with a small hole
+in its center tied over the top. Into this hole a strong cord is
+passed, with a small piece of wood attached to the end to keep it
+inside the bellows, while the other end is attached to a bent bamboo
+firmly fixed into the ground close by. This bamboo acts as a spring,
+drawing up the string, and consequently the leather cover of the
+bellows, to its utmost stretch, while air enters through the central
+hole. When thus filled, a man places his foot on the hide, closing the
+central hole with his heel, and then throwing the whole weight of his
+body on to that foot, he depresses the hide, and drives the air out
+through a bamboo tube inserted in the side and communicating with the
+furnace. At the same time he pulls down the bamboo with the arm of
+that side. Two such bellows are placed side by side, a thin bamboo
+tube attached to each, and both entering the one tuyere; and so by
+jumping on each bellows alternately, the workman keeps up a continuous
+blast.
+
+[Illustration: Fig. 2.--PLAN OF INDIAN BLAST FURNACE AND BLOWING
+MACHINE.]
+
+The Figs. 1 and 2 are taken from sketches, and the description from
+particulars, by Mr. Blandford, who was for some years on the
+Geological Survey of India, and had exceptional opportunities in his
+journeyings of observing the customs and occupations of the Indian
+iron smelters. The blowing machine is an especially wonderful and
+effective machine, and was first described and illustrated by Mr.
+Robert Rose, in a Calcutta publication, more than half a century ago.
+He also had seen it used in iron making in India.--_Colliery
+Guardian._
+
+       *       *       *       *       *
+
+
+
+
+WOOD OIL.
+
+
+Wood oil is now made on a large scale in Sweden from the refuse of
+timber cuttings and forest clearings, and from stumps and roots.
+Although it cannot well be burned in common lamps, on account of the
+heavy proportion of carbon it contains, it is said to furnish a
+satisfactory light in lamps specially made for it; and in its natural
+state it is the cheapest illuminating oil. There are some thirty
+factories engaged in its production, and they turn out about 40,000
+liters of the oil daily. Turpentine, creosote, acetic acid, charcoal,
+coal-tar oils, etc., are also obtained from the same materials as the
+wood oil.
+
+       *       *       *       *       *
+
+
+
+
+SOAP.
+
+By HENRY LEFFMANN, M.D.
+
+
+Although the use of soap dates from a rather remote period, the
+chemist is still living, at an advanced age, to whom we are indebted
+for a knowledge of its composition and mode of formation. Considerably
+more than a generation has elapsed since Chevreul announced these
+facts, but a full appreciation of the principles involved is scarcely
+realized outside of the circle of professional chemists. Learned
+medical and physiological writers often speak of glycerin as the
+"sweet principle of fats," or term fats compounds of fatty acids and
+glycerin. Indeed, there is little doubt that the great popularity of
+glycerin as an emollient arose from the view that it represented the
+essential base of the fats. With regard to soap, also, much erroneous
+and indistinct impression prevails. Its detergent action is sometimes
+supposed to be due to the free alkali, whereas a well-made soap is
+practically neutral.
+
+A desire to secure either an increased detergent, cleansing, or other
+local effect has led in recent years to the introduction into soaps of
+a large number of substances, some of which have been chosen without
+much regard to their chemical relations to the soap itself. The result
+has been the enrichment of the materia medica with a collection of
+articles of which some are useful, and others worse than useless. The
+extension of the list of disinfectant and antiseptic agents and the
+increased importance of the agents, in surgery, have naturally
+suggested the plan of incorporating them with soaps, in which form
+they will be most convenient for application. Accordingly, the
+circulars of the manufacturing pharmacists have prominently displayed
+the advantages of various disinfecting soaps.
+
+Among these is a so-called corrosive sublimate soap, of which several
+brands are on sale. One of these, containing one per cent. of
+corrosive sublimate, is put on the market in cakes weighing about
+sixteen hundred grains, and each cake, therefore, contains sixteen
+grains of the drug--a rather large quantity, perhaps, when it is
+remembered that four grains is a fatal dose. Fortunately, however, for
+the prevention of accidents, but unfortunately for the therapeutic
+value of the soap, a decomposition of the sublimate occurs as soon as
+it is incorporated in the soap mass, by which an insoluble mercurial
+soap is formed. This change takes place independently of the alkali
+used in the soap; in fact, as mentioned above, a well-made soap
+contains no appreciable amount of free alkali, but is due to the
+action of the fat acids. Corrosive sublimate is _incompatible_ with
+any ordinary soap mass, and this incompatibility includes not only
+other soluble mercurial salts, but also almost all the mineral
+antiseptics, such as zinc chloride, copper sulphate, iron salts. Some
+of the preparations of arsenic may, however, be incorporated with soap
+without decomposition.
+
+Such being the chemical facts, we must admit that no reliance can be
+placed in corrosive sublimate soaps as germicide agents. It must not
+be supposed that this incompatibility interferes with the use of these
+soaps for general therapeutic purposes. It is only the specific
+germicide value which is destroyed. Since the fats used in soap
+manufacture yield oleic acid, we will have a certain amount of
+mercuric oleates formed together with stearate and other salts, and
+for purposes of inunction these salts might be efficient. Still the
+physician would prefer, doubtless, to use the specially prepared
+mercurial.
+
+In producing, therefore, a disinfecting soap, being debarred from
+using the metallic germicides, we are fortunate in the possession of a
+number of efficient agents, organic in character, which may be used
+without interference in soaps.
+
+Among these are thymol, naphthol, oil of eucalyptus, carbolates, and
+salicylates. There is no chemical incompatibility of these with soap,
+and as they are somewhat less active, weight for weight, than
+corrosive sublimate, they are capable of use in larger quantities with
+less danger, and can thus be made equally efficacious.
+
+It is in this direction, therefore, that we must look for the
+production of a safe and reliable antiseptic soap.
+
+There is not much exact knowledge as to the usefulness of such
+additions to soap as borax and glycerin. They are frequently added,
+and highly spoken of in advertisements. Borax is a mild alkaline body,
+and as a detergent is probably equivalent to a slight excess of
+caustic soda. Glycerin, although originally considered an emollient,
+probably on account of its source and physical properties, is in
+reality, to some skins at least, a slight irritant. It is, in fact, an
+alcohol, not a fat. It does not pre-exist in fats, but is formed when
+the fat is decomposed by alkali or steam.
+
+In ordinary cases, soap owes its detergent effect to a decomposition
+which occurs when it is put in water.
+
+A perfectly neutral soap, that is, one which contains the exact
+proportion of alkali and fat acid, will, when placed in cold water,
+decompose into two portions, one containing an excess of the acid, the
+other an excess of alkali. The latter dissolves, and gives a slightly
+alkaline solution; the former precipitates, and gives the peculiar
+turbidity constituting "suds." These reactions must be kept in mind in
+determining the effect of the addition of any special substance to the
+soap.--_The Polyclinic._
+
+       *       *       *       *       *
+
+
+
+
+OPTICAL ERRORS AND HUMAN MISTAKES.[1]
+
+  [Footnote 1: Read before the American Association, Buffalo,
+  August, 1886.]
+
+By ERNST GUNDLACH.
+
+
+I wish to call attention to a few mistakes that are quite commonly
+made by microscopists and writers in stating the result of their
+optical tests of microscope objectives.
+
+If the image of an object as seen in the microscope appears to be
+unusually distorted and indistinct toward the edge of the field, and
+satisfactory definition is limited to a small portion of the center,
+the cause is often attributed to the spherical aberration of the
+objective, while really this phenomenon has nothing to do with that
+optical defect of the objective, if any exists, but is caused by a
+lack of optical symmetry. If a perfectly symmetrical microscope
+objective could be constructed, then, with any good eye-piece, it
+would make no difference to the definition of the object were it
+placed either in the center or at the edge of the field, even if the
+objective had considerable spherical aberration. But, unfortunately,
+our most symmetrical objectives, the low powers, leave much to be
+desired in this respect, while our wide angle, high powers are very
+far from symmetrical perfection.
+
+There are two causes of this defect in the latter objectives, one
+being the extreme wideness of their angular apertures, and the other
+the great difference in the distances of the object and the image from
+the optical center of the objectives.
+
+Another mistake is often made in regard to the cause of certain
+prismatic colors that are sometimes, in a striking degree, produced by
+otherwise good objectives. According to the nature of these colors,
+whether yellow or blue, green or indigo, they are generally regarded
+as evidences of either chromatic over or under correction of the
+objective. Of course the presence of either of these defects is
+certainly and correctly indicated by the appearance of one or the
+other of the colors, under certain circumstances; but the simple
+visibility of prismatic color is by no means a reliable indication of
+over or under correction of color, and, indeed, to the honor of our
+opticians, it may be stated that very few objectives are made that
+cannot justly be called achromatic in the general sense of the term.
+By far the most common causes of prismatic color, in otherwise
+carefully constructed objectives, are the so-called chromatic
+aberrations of second or higher order. Every achromatic lens which is,
+as it should be, at its best at about two-thirds of its aperture, is
+inside of this ring or zone, toward the center slightly under and
+outside, toward the edge, slightly over corrected. This defect is the
+greater, the less the difference of the dispersive powers of the two
+glasses used in the construction of the lens, for a given proportion
+of their refractive indexes, and therefore the degree of visibility of
+the colors of the aberrations of the second order depends greatly on
+the nature of the glass employed in the construction of the lens.
+
+This defect may be corrected by a suitable combination of two or more
+lenses, though not without again having similarly, as in the
+correction of the first color, some faint remnants of color, the
+aberrations of third or still higher order. But even the correction of
+the third or still higher order may, if the angular aperture is very
+wide, leave quite visible and disturbing remnants of color.
+
+Another and not uncommon explanation of the cause of this unwelcome
+color, though not so serious and damaging a charge to the maker of the
+objectives, is its attribution to the so-called "secondary spectrum."
+This error, like that previously mentioned, is certainly indicated by
+the appearance of certain colors under certain conditions, but being,
+as a rule, one of the least defects of even our best objectives in
+most cases, it is probably not the true source of the disturbance.
+
+The secondary spectrum is very commonly confounded with the chromatic
+aberration of higher order. While the latter is produced by
+imperfections in the form of the lens, the former is due to an
+imperfection of the optical qualities of the material from which the
+lens is constructed, the crown and flint glass.
+
+A glass prism of any angle will project upon a white surface a
+spectrum of any length, according to the arrangement of the light
+source, the screen, and the prism. So with two prisms of the same kind
+of glass, but of different angles, two spectra can be produced of
+exactly equal length, so that if one is brought over the other, with
+the corresponding colors in line, they will appear as one spectrum.
+But if one of the prisms is made of crown and the other of flint
+glass, then their spectra cannot be arranged so that all their
+corresponding colors would be in line, for the proportional distances
+of the different colors differ in the two spectra. If two colors of
+the spectra are, by suitable arrangement, brought exactly in line,
+then the others will be out. The two spectra do not coincide, and the
+result, if an achromatic lens be made of these glasses, must be a
+remnant of color which cannot be neutralized. This remnant is the
+secondary spectrum.
+
+Although this peculiar disharmony in the dispersive powers of the two
+glasses, crown and flint, was discovered almost immediately after
+achromatism was invented, it was only recently that the first
+successful attempts were made to produce different glasses, which,
+possessing the other requirements for achromatic objectives, would
+produce coincident spectra, or nearer so than the ordinary crown and
+flint glass do. It was about twelve years ago, if my memory serves me,
+when I learned that a well-known English firm, engaged in the
+manufacture of optical glass, had brought out some new glass possessed
+of the desired qualities, and a little later I received a circular
+describing the glass. But at the same time I learned that the new
+glass was very soft and difficult to polish, and also that it had to
+be protected from the atmosphere, and further, that an English
+optician had failed to construct an improved telescope objective from
+it. I had ordered some samples of the glass, but never received any.
+
+A few months ago, news from Europe reached this country that another
+and seemingly more successful attempt had been made to produce glass
+that would leave no secondary spectrum, and that Dr. Zeiss, the famous
+Jena optician, had constructed some new improved objectives from it.
+But the somewhat meager description of these objectives, as given by
+an English microscopist, did not seem fit to excite much enthusiasm
+here as to their superiority over what had already been done in this
+country. Besides this, the report said that the new objectives were
+five system, and also that extra eye-pieces had to be used with them.
+I confess I am much inclined to attribute the optical improvement,
+which, according to Dr. Abbe's own remark, is very little, more to the
+fact that the objectives are five system than to the new glass used in
+their construction.
+
+After a close study of a descriptive list of the new glass, received a
+week or two ago from the manufacturers, I find, to my great regret,
+that this new glass seems to suffer from a similar weakness to that
+made by the English firm twelve years ago; as all the numbers of the
+list pointed out by the makers as having a greatly reduced secondary
+spectrum are accompanied with the special remark "to be protected."
+Furthermore, from a comparison of the dispersive and refractive powers
+of these glasses, as given in the list, I find that objectives
+constructed from them will leave so great aberrations of higher order,
+both spherical and chromatic, that the gain by the reduction of the
+secondary spectrum would be greatly overbalanced.
+
+In conclusion, I wish to say that while I would beware of
+underestimating the great scientific and practical value of the
+endeavor of the new German glass makers to produce improved optical
+glass, and the great benefit accruing to opticians and all others
+interested in the use of optical instruments, I think it wise not to
+overestimate the real value of the defects of the common crown and
+flint glass, which I have sought to explain in this paper. And, for
+myself, I prefer to fight the more serious defects first, and when its
+time has come I will see what can be done with the secondary spectrum.
+
+       *       *       *       *       *
+
+
+
+
+PROBABLE ISOLATION OF FLUORINE. DECOMPOSITION OF HYDROFLUORIC ACID
+BY AN ELECTRIC CURRENT.
+
+By M.H. MOISSAN.
+
+
+In a former memoir[1] we showed that it was possible to decompose
+anhydrous hydrofluoric acid by the action of an electric current. At
+the negative pole hydrogen collects; at the positive pole a gaseous
+body is disengaged, having novel properties. The experiment was
+performed in a platinum U tube, closed by stoppers of fluorite, and
+having at the upper part of each branch a small delivery tube, also of
+platinum. Through the stopper passes a platinum rod, which acts as
+electrode. The metal employed for the positive pole is an alloy
+containing 10 per cent. of iridium.
+
+  [Footnote 1: _Comptes Rendus_, vol. cii., p. 1543, and _Chemical
+  News_, vol. liv., p. 36.]
+
+To obtain pure anhydrous hydrofluoric acid, we begin by preparing
+fluorhydrate of fluoride of potassium, taking all the precautions
+pointed out by M. Fremy. When the salt is obtained pure, it is dried
+on a water bath at 100 deg., and the platinum capsule containing it is
+then placed in a vacuum in the presence of concentrated sulphuric
+acid, and two or three sticks of potash fused in a silver crucible.
+The acid and potash are renewed every morning for a fortnight, and the
+vacuum is kept at 2 cm. of mercury. Care must be taken during this
+desiccation to pulverize the salt every day in an iron mortar, so as
+to renew the surface. When the fluorhydrate contains no more water it
+falls to powder, and is then fit to serve for the preparation of
+fluoric acid; the fluorhydrate of fluoride of potassium, if well
+prepared, is much less deliquescent than the fluoride.
+
+When the fluoride is quite dry, it is quickly introduced into a
+platinum alembic, which has just been dried by heating it to redness.
+The whole is kept at a gentle temperature for an hour or an hour and a
+half, so as to allow the decomposition to commence very slowly; the
+first portions of acid which come over are rejected as they carry with
+them traces of water remaining in the salt. The platinum receiver is
+then attached, and the heat increased, allowing the decomposition to
+proceed with a certain degree of slowness. The receiver is then
+surrounded with a mixture of ice and salt, and from this moment all
+the hydrofluoric acid is condensed as a limpid liquid, boiling at
+19.5 deg., very hygroscopic, and, as is well known, giving abundant fumes
+in presence of the atmospheric moisture.
+
+During this operation the platinum U tube, dried with the greatest
+care, has been fixed with a cork in a cylindrical glass vessel
+surrounded with chloride of methyl. Up to the moment of introducing
+the hydrofluoric acid, the leading tubes are attached to drying tubes
+containing fused caustic potash. To introduce the hydrochloric acid
+into the apparatus, it may be absorbed through one of the lateral
+tubes in the receiver in which it is condensed.
+
+In some experiments we have directly condensed the hydrofluoric acid
+in the U tube surrounded with chloride of methyl; but in this case
+care must be taken that the tubes are not clogged up by small
+quantities of fluoride carried over, which would infallibly lead to an
+explosion and projections, which are always dangerous with so
+corrosive a liquid.
+
+When we have introduced in advance in the small platinum apparatus a
+determined amount of hydrofluoric acid cooled with chloride of methyl,
+in tranquil ebullition at a temperature of -23 deg., the current of 20
+cells of Bunsen large size, arranged in series, is passed through by
+means of the electrodes. An amperemeter in the circuit admits of the
+intensity of the current being observed.
+
+If the hydrofluoric acid contains a small quantity of water, either by
+accident or design, there is always disengaged at the positive pole
+ozone, which has no action on crystallized silicium. In proportion as
+the water contained in the acid is thus decomposed, it is seen by the
+amperemeter that the conductivity of the liquid rapidly decreases.
+With absolutely anhydrous hydrofluoric acid the current will no longer
+pass. In many of our experiments we have succeeded in obtaining an
+acid so anhydrous that a current of 25 amperes was entirely arrested.
+
+To render the liquid conducting, we have added before each experiment
+a small quantity of dried and fused fluorhydrate of fluoride of
+potassium. In this case, decomposition proceeds in a continuous
+manner; we obtain at the negative pole hydrogen, and at the positive
+pole a regular disengagement of a colorless gas in which crystallized
+silicium in the cold burns with great brilliancy, becoming fluoride of
+silicium. This latter gas has been collected over mercury, and
+accurately characterized.
+
+Deville's adamantine boron burns in the same manner, but with more
+difficulty, becoming fluoride or boron. The small quantity of carbon
+and aluminum which it contains impedes the combination. Arsenic and
+antimony in powder combine with this gaseous body with incandescence.
+Sulphur takes fire in it, and iodine combines with a pale flame,
+losing its color. We have already remarked that it decomposes cold
+water, producing ozone and hydrofluoric acid.
+
+The metals are attacked with much less energy. This is due, we think,
+to the small quantity of metallic fluoride formed preventing the
+action being very deep. Iron and manganese in powder, slightly heated,
+burn with sparks. Organic bodies are violently attacked. A piece of
+cork placed near the end of the platinum tube, where the gas is
+evolved, immediately carbonizes and inflames. Alcohol, ether, benzol,
+spirit of turpentine, and petroleum take fire on contact.
+
+The gas evolved at the negative pole is hydrogen, burning with a pale
+flame, and producing none of these reactions.
+
+When the experiment has lasted several hours, and there is not enough
+hydrofluoric acid left at the bottom of the tube to separate the two
+gases, they recombine in the apparatus in the cold, with violent
+detonation.
+
+We have satisfied ourselves, by direct experiment, that a mixture of
+ozone and hydrofluoric acid produces none of the reactions described
+above.
+
+It is the same with gaseous hydrofluoric acid. Finally we may add that
+the hydrofluoric acid employed, as well as the hydrofluorate of
+fluoride, were absolutely free from chlorine.
+
+The gas obtained in our experiments is therefore either fluorine or a
+perfluoride of hydrogen.
+
+New experiments are necessary to settle this last point. We hope soon
+to lay the results before the Academy.--_Comptes Mendus_, vol. ciii.,
+p. 202, July 19, 1886; _Chem. News._
+
+       *       *       *       *       *
+
+
+
+
+COHESION AND COHESION FIGURES.[1]
+
+  [Footnote 1: Notes from a lecture given to the Halifax Scientific
+  Society, July 19, 1886.]
+
+By WILLIAM ACKROYD, F.I.C.
+
+
+_1. A Law of Solubility._
+
+It is customary to regard cohesion as the force which binds together
+molecules of the same substance, and in virtue of which the particles
+of solids and liquids are kept together, and also to speak of the
+attraction exerted between particles of two different bodies as
+adhesion. The distinction between cohesion and adhesion is a
+conventional one. The similarity, if not identity, of the two forces
+is demonstrated by the fact that while cohesion is exerted between
+particles of the _same_ body, adhesion is exerted with most force
+between particles of _allied_ bodies. Generally speaking, organic
+bodies require organic solvents; inorganic bodies, inorganic solvents.
+For example, common salt is highly soluble in water, but not in ether,
+and many fats are soluble in ether, but not in water. So many cases
+like these will suggest themselves to the chemist that I am justified
+in making the following generalization: _A body will dissolve in a
+solvent to which it is allied more readily than in one to which it in
+highly dissimilar._ Exceptions to the law undoubtedly exist, but none
+so striking as the following in support of it, viz., that the metal
+mercury is the only known true solvent for many metals at the normal
+temperature.
+
+
+_2. Its Connection with Mendeleeff's Periodic Law._
+
+From this standpoint the whole subject of solution is deserving of
+fresh attention, as it appears highly probable that, just as Prof.
+Carnelley has shown by the use of my meta-chromatic scale, the colors
+of chemical compounds come under definite laws, which he has
+discovered and formulated in connection with Mendeleeff and Newlaud's
+periodic law,[2] so, likewise, may the solubility of an allied group
+of compounds, in regard to any given solvent under constant conditions
+of temperature, conform to similar laws; that, e.g., the chlorides
+of H, Na, Cu, and Ag, in Mendeleeff's Group I., may vary in their
+solubility in water from an extreme of high solubility in the case of
+hydrogen chloride to the opposite extreme of comparative insolubility
+in the case of silver chloride. In this natural series of compounds,
+hydrogen chloride is the body nearest akin to water, and silver
+chloride the most remote in kinship.
+
+  [Footnote 2: _Philosophical Magazine_, August, 1884.]
+
+
+_3. A Solidified Vortex Ring._
+
+It is in virtue of cohesion that a freely suspended drop of liquid
+assumes the spherical form. If such a sphere be dropped on to the
+surface of a liquid of higher specific gravity at rest, one obtains
+what is called the cohesion figure of the substance of the drop. A
+drop of oil, e.g., spreads out on the surface of water until it is a
+circular thin film of concentric rings of different degrees of
+thickness, each displaying the characteristic colors of thin plates.
+The tenuity of the film increases; its cohesion is overcome; lakelets
+are formed, and they merge into each other. The disintegrated portions
+of the film now thicken, the colors vanish, and only islets of oil
+remain. Some liquid drops of the same or higher sp. gr. than water do
+not spread out in this fashion, but descend below the surface of the
+liquid, and, in descending, assume a ring shape, which gradually
+spreads out and breaks up into lesser rings. Such figures have been
+termed submergence cohesion figures; they are vortex rings. I have
+solidified such vortex rings in their first stage of formation. If
+drops of melted sulphur, at a temperature above that of the viscous
+state, be let fall into water, the drops will be solidified in the
+effort to form the ring, and the circular button, thick in the rim and
+thin in the center, may be regarded as a solidified vortex ring of
+plastic sulphur.
+
+
+_4. That a Submergence Cohesion Figure is a Vortex Ring._
+
+It may be shown that the conditions of the formation of a submergence
+cohesion figure are those which exist in the formation of an aerial
+vortex. Those conditions in their greatest perfection are (1) a
+spherical envelope of a different nature from the medium in which the
+rings are produced; (2) a circular orifice opening into the medium;
+and (3) a percussive impact on the part of the sphere opposite the
+orifice. In the production of vortex rings of phosphorus pentoxide in
+the making of phosphoreted hydrogen, the spherical envelope is water,
+the orifice the portion of the bubble which opens into the air
+immediately it rises to the surface, and the impact is furnished by
+gravity. So, also, in the case of a submergence cohesion figure, the
+spherical envelope is the air surrounding the drop, the orifice the
+portion of it which first comes in contact with the liquid at rest;
+and here again the impact is due to gravity more directly than in the
+former case. These conditions are somewhat imperfectly copied in the
+ordinary vortex box, which is usually cubical in form, with a circular
+orifice in one side, and a covering of canvas on the opposite one,
+which is hit with the fist.
+
+       *       *       *       *       *
+
+[AMERICAN CHEMICAL JOURNAL.]
+
+
+
+
+THE DETERMINATION OF NITRIC ACID BY THE ABSORPTION OF NITRIC OXIDE
+IN A STANDARD SOLUTION OF PERMANGANATE OF POTASSIUM.
+
+By H.N. MORSE and A.F. LINN.
+
+
+The method which we propose consists in the conversion of the nitric
+acid into nitric oxide; the absorption of the latter in a measured,
+but excessive, quantity of a standard solution of permanganate of
+potassium; and the subsequent determination of the excess of the
+permanganate by means of a standard solution of oxalic acid or
+sulphate of manganese.
+
+
+THE APPARATUS.
+
+A is an apparatus for the generation of carbon dioxide free from air,
+which will be explained hereafter.
+
+B is a flask, having a capacity of 125 or 150 c.c., in which the
+nitrate is decomposed in the usual manner by means of ferrous chloride
+and hydrochloric acid.
+
+C is a small tube for the condensation of the aqueous hydrochloric
+acid which distills over from B.
+
+D is a Geissler bulb, containing a concentrated solution of potassium
+carbonate, to arrest any acid vapors coming from C.
+
+E, E are two pieces of ordinary combustion tubing, having a length of
+about 650 or 700 mm., in which is placed the permanganate solution
+employed for the absorption of the nitric oxide. Their open ends are
+provided with lips in order to facilitate the pouring of liquids from
+them, care being taken not to so distort the ends that rubber stoppers
+cannot be made to fit them tightly. They are placed in a nearly
+horizontal position in order to diminish the pressure required to
+force the gases through the apparatus and thus lessen the danger of
+leakage through the rubber joints.
+
+_a_ is a tube through which the ferrous chloride and hydrochloric acid
+are introduced into B, as in the method of Tiemann-Schulze.
+
+_b_ serves for the introduction of carbon dioxide to expel the air
+before the decomposition of the nitrate, and the nitric oxide
+afterward.
+
+_c_ is an unbroken tube ending at the lower surface of the stopper in
+B, and at the bottom of C.
+
+The rubber joint, _d_, is furnished with a Mohr and also a screw pinch
+cock. The joints, _e_ and _f_, are furnished with Mohr pinch cocks.
+The rubber tubing upon these should be of the best quality, and must
+be carefully tied.
+
+[Illustration: DETERMINATION OF NITRIC ACID.]
+
+
+THE SOLUTIONS.
+
+In consequence of the large volume of the permanganate solution
+required for the complete absorption of the nitric oxide, we have
+found it advantageous to use three solutions instead of two.
+
+1. A solution of permanganate such that one c.c. is equivalent to
+about fifteen milligrammes of nitrate of potassium, according to the
+reaction:
+
+  KMnO_{4} + NO = KNO_{3} + MnO_{2}.
+
+This solution is employed for the absorption of the nitric oxide. Its
+strength need not be exactly known. There is no objection to a more
+concentrated solution, except that which pertains to all strong
+standard solutions, namely, that a small error in measurement would
+then give a larger error in the results. 100 c.c. of this solution are
+required for each determination, and the measurement is always made in
+one and the same 100 c.c. measuring flask, which, if necessary, should
+be labeled to distinguish it from that used for solution No. 2.
+
+2. A solution of oxalic acid which is very slightly stronger than that
+of the permanganate just described--that is, a solution such that one
+c.c. of it will somewhat more than decompose one c.c. of the
+permanganate, according to the reaction:
+
+  2KMnO_{4} + 3H_{2}SO_{4} + 5C_{2}H_{2}O_{4}.2H_{2}O =
+  K_{2}SO_{4} + 2MnSO_{4} + 18H_{2}O + 10CO_{2}.
+
+The exact strength of this solution need not be known, since we only
+require the difference in value between it and solution No. 1, which
+is determined by means of solution No. 3. 100 c.c. of this solution
+are also required for each determination, and the measurement, as in
+the preceding case, is always made in the same 100 c.c. measuring
+flask.
+
+3. A dilute, carefully standardized solution of permanganate of
+potassium.
+
+The method of using these solutions is as follows: 100 c.c. of No. 1
+and No. 2 are measured off (each solution in its own measuring flask),
+brought together in a covered beaker glass, and acidified with dilute
+sulphuric acid. The excess of oxalic acid is then determined by means
+of solution No. 3.
+
+When it is desired to make a determination of nitric acid, 100 c.c. of
+solution No. 1 are measured off, and as much of it as may be
+convenient is poured into the tubes, E, E, together with about a
+gramme of zinc sulphate for each tube, which substance appears to
+considerably facilitate the absorption of the nitric oxide by the
+permanganate. When the operation is over, the contents of E, E are
+poured into a beaker glass. 100 c.c. of solution No. 2 are then
+measured off, and a portion, together with a little sulphuric acid,
+poured into E, E, to dissolve the oxide of manganese which has
+separated during the absorption of the nitric oxide. The oxide having
+been dissolved, the liquid in E, E, and the rinsings of the tubes,
+also the residues of permanganate and oxalic acid left in the
+measuring flasks, and the rinsings from these, are all brought
+together in the same beaker glass. Finally, the amount of solution
+No. 3 required to decompose the excess of oxalic acid is determined.
+If we subtract from the amount thus found the quantity of permanganate
+required to equalize solutions Nos. 1 and 2 (previously ascertained),
+we shall have the amount of permanganate actually reduced by the
+nitric oxide, according to the reaction:
+
+  6KMnO_{4} + 10NO = 3K_{2}O + 6MnO + 5N_{2}O_{5};
+
+in other words, on the basis that one molecule of potassium
+permanganate will oxidize one and two-thirds molecules of nitric
+oxide:
+
+  (KMnO_{4} = 1-2/3 NO).
+
+The method of using the apparatus is simple. The nitrate is placed in
+B, and the joints made tight, except that at _f_, which is left open.
+A current of carbon dioxide is passed through the apparatus until all
+of the air has been displaced. Connection is then made at _f_, and
+soon afterward the current of carbon dioxide is shut off at _d_.
+
+The flask, B, is now heated as long as may be necessary in order to
+produce, on cooling, the diminished pressure required for the
+introduction of the ferrous chloride and hydrochloric acid. Before
+removing the flame, the joint at _f_ is closed to prevent the return
+of the permanganate solution.
+
+As soon as the flask, B, has become sufficiently cool, the ferrous
+chloride and hydrochloric acid are introduced through the tube, _a_
+(which has been full of water from the first), in the same manner and
+quantities as in the well-known Tiemann-Schulze method.
+
+The pinch cock at _d_ is then opened, and the apparatus allowed to
+fill with carbon dioxide. When the pressure has become sufficient to
+force the gas through the solution of permanganate, the pinch cock at
+_f_ is removed. It should be opened only slightly and with great
+caution at first, unless one is certain that the pressure is
+sufficient. If the pressure is insufficient, the fact will be made
+apparent by a rise of the permanganate in the small internal tube.
+
+The flow of carbon dioxide is now reduced to a very slow current, or
+entirely cut off. The contents of B are slowly heated, until the
+decomposition of the nitrate is complete and the greater part of the
+nitric oxide has been expelled, when the apparatus is again closed at
+_f_ and _d_, and allowed to cool. The tube, _a_, is then washed out,
+by the introduction through it into B of a few cubic centimeters of
+strong hydrochloric acid.
+
+The process of filling the apparatus with carbon dioxide, and of
+heating the contents of B, is repeated. When it becomes apparent, from
+the light color of the liquid in B, that all of the nitric oxide has
+been expelled from it, the current of carbon dioxide is increased and
+the heating discontinued. Care must be taken, however, not to admit
+too strong a current of carbon dioxide, lest some of the nitric oxide
+should be forced unabsorbed through the permanganate solution. It is
+also necessary, for the same reason, to avoid too rapid heating during
+the decomposition of the nitrate.
+
+When all of the nitric oxide has been forced into the solution of
+permanganate, the determination is made in the manner already
+described.
+
+To test the method, nine determinations were made with quantities of
+pure nitrate of potassium varying from 100 to 200 milligrammes. The
+maximum difference between the volumes of permanganate actually used
+and those calculated was 0.05 c.c., while the main difference was
+0.036 c.c. The measurements of the permanganate were made from a
+burette which had been carefully calibrated. We also made a number of
+determinations, using a solution of manganous sulphate in the place of
+the oxalic acid. The advantage of this method lies in the fact that it
+is not necessary to dissolve the oxide which is precipitated upon the
+glass within the tubes, E, E, since, in the presence of an excess of
+permanganate, the reduction by nitric oxide extends only to the
+formation of MnO_{2}; also in the fact that the solution of manganous
+sulphate is more stable than that of oxalic acid. A solution of the
+sulphate having been once carefully standardized, can be used for a
+long time to determine the value of permanganate solutions.
+
+The details of the method are as follows: A solution of manganous
+sulphate slightly stronger than No. 1 is prepared.
+
+The difference between 100 c.c. of it and 100 c.c. of No. 1 is
+ascertained, according to the method of Volhard, by means of solution
+No. 3.
+
+The contents of E, E, together with the rinsings from the tubes, are
+poured into a capacious flask. 100 c.c. of the manganous sulphate and
+a few drops of nitric acid are then added, and the whole boiled.
+Finally, the excess of manganous sulphate is determined, in the manner
+described by Volhard, by means of solution No. 3. Subtracting from the
+total amount of permanganate thus used the quantity required to
+equalize the 100 c.c. of solution No. 1 and the 100 c.c. of the
+manganous sulphate, we shall have the quantity of permanganate reduced
+by the nitric oxide.
+
+It must, however, be remembered that the value of solution No. 3 is
+now to be calculated on the basis of the equation KMnO_{2} + NO =
+KNO_{3} + MnO_{2}. One molecule of permanganate equals one molecule of
+nitric oxide when manganous sulphate is used, since no part of the
+permanganate employed in this method is reduced below the superoxide
+condition. In other words, solution No. 3 now represents only
+three-fifths as much nitric acid as it does when oxalic acid is used.
+
+The results obtained by this method were moderately satisfactory, but
+not quite so exact as those obtained when oxalic acid was used. A
+series of four determinations gave differences, between the volumes of
+permanganate calculated and used, of 0.05 to 0.15 c.c.
+
+The principal objection to the method lies in the difficulty of
+determining, in the presence of the brown oxide of manganese, the
+exact point at which the oxidation is complete.
+
+The carbon dioxide generator, A, was devised by us to take the place
+of the ordinary generators, in which marble is used. We have found
+that a submersion of twenty hours in boiling water does not suffice to
+completely remove the air which, as is well known, is contained in
+ordinary marble; hence some other substance must be employed as a
+source of the gas. In the apparatus which we are about to describe,
+the acid carbonate of sodium is used.
+
+It consists of a long, narrow cylinder (450 x 60 mm.); a tightly
+fitting rubber stopper, through which three tubes pass, as shown in
+the figure; a small cylinder, F, containing mercury; and a sulphuric
+acid reservoir, G.
+
+The tube, _g_, is drawn out to a fine point at the end and curved, so
+that the acid which is delivered into A falls upon and runs down the
+outside of the tube. The tube, h, dips under the mercury in F. G and
+_g_ are connected by means of a long piece of rubber tubing which is
+supplied with a screw pinch cock.
+
+The apparatus is made to give any required pressure by raising or
+lowering G and F; but the elevation of G, as compared with that of F,
+should always be such that the gas will force its way through h rather
+than g. The upper part of the cylinder, F, is filled with cotton wool
+to prevent loss of mercury by spattering.
+
+The material placed in A consists of a saturated solution of acid
+carbonate of sodium, to which an excess of the solid salt has been
+added. The sulphuric acid is the ordinary dilute. The apparatus, if
+properly regulated, serves its purpose very well. The principal
+precaution to be observed in using it is to avoid a too sudden
+relieving of the pressure, which would, of course, result in the
+introduction of an unnecessarily large quantity of sulphuric acid into
+A.
+
+       *       *       *       *       *
+
+
+
+
+WATER OF CRYSTALLIZATION.
+
+By W.W.J. NICOL, M.A., D.Sc.
+
+
+When a hydrated salt is dissolved, does it retain its water of
+crystallization, or does this latter cease to be distinguishable from
+the solvent water? Both views have found advocates among chemists who
+have looked at the question of solution, and both have been supported
+by arguments more or less to the point. But among the possible means
+of solving this question there is one which has entirely escaped the
+notice of those interested in the subject. And those who hold that
+water of crystallization exists in solution have been entirely
+oblivious of the fact that, while they are ready to accept the results
+of the modern science of thermo-chemistry, and to employ them to
+support their views on hydration, yet these very results, if correct,
+prove without a shadow of a doubt that water of crystallization does
+not exist in solution.
+
+The proof is so clear and self-evident when once one's attention is
+directed to it, that, though I intend to develop it more fully on
+another occasion, I feel that it is better to publish an outline of it
+at once.
+
+Thomsen has found that the heat of neutralization of the soluble bases
+of the alkalies and alkaline earths with sulphuric acid has a mean
+value of 31.150 c. within very narrow limits. When hydrochloric or
+nitric acid is employed, the value is 27.640 c., also within very
+narrow limits. Now, this agreement of the six bases in their behavior
+with sulphuric acid, much more of the seven bases with both HNO_{3}
+and HCl, is so close that it cannot be regarded as accidental, but, in
+the words of Meyer, the heat of formation of a salt in aqueous
+solution is a quantity made up of two parts, one a constant for the
+base, the other for the acid. But of the twenty salts thus formed,
+some are anhydrous in the solid state, others have water of
+crystallization, up to ten molecules in the case of Na_{2}SO_{4}. If
+water of crystallization exists in solution, it will be necessary to
+suppose that this agreement is accidental, which is absurd, as a
+glance at the probabilities will show. Thomsen himself expressly
+states that he regards the dissolved state as one in which the
+conditions are comparable for all substances; this would be impossible
+if water of crystallization were present.
+
+A still stronger proof is afforded by the "_avidity_" of Thomsen or
+the "_affinity_" of Ostwald; both have worked on the subject, taking
+no account of water of crystallization, and the results, e.g., for
+H_{2}SO_{4} and HCl with NaHO, where water of crystallization _may_
+come in, are entirely confirmed by Ostwald's results on inversion and
+etherification, where there can be no water of crystallization.
+
+The proof is complete, water of crystallization cannot be attached to
+the salt in solution, or if it is, no heat is evolved on union more
+than with solvent water. The alternative is to suppose that the whole
+of the above thermo-chemical results are coincidences.
+
+       *       *       *       *       *
+
+
+
+
+ALPINE FLOWERS IN THE PYRENEES.
+
+
+Bagneres De Luchon, in the department of the Haute Garonne, is a gay
+town of some 5,000 inhabitants. A friend told me that he once suffered
+so much from the heat there in June, that he determined never to go to
+the Pyrenees again. We were there the second week in June, and we
+suffered more from rain and cold, and were very glad of a fire in the
+evening.
+
+Except to the south, in the direction of the Porte de Venasque, one of
+the chief mule passes into Spain during summer, where there are fine
+snow-capped mountains, the scenery from the town is not grand, but it
+is within easy reach of the wildest parts of the Pyrenees.
+
+It is the nearest town to the Maladetta, their highest point, in which
+the Garonne rises, and among whose rocks is one of the last
+strongholds of the ibex or bouquetin, the "wild goat" mentioned by
+Homer. Eagles and vultures are to be seen sailing about the sky near
+Luchon nearly every day, and bears, which in the Pyrenees are neither
+mythical nor formidable, descend to within a few miles of the town
+after wild strawberries, which abound there.
+
+We heard of two female peasants lately gathering wild strawberries who
+were suddenly confronted with competitors for the spoil in the shape
+of a she bear and two cubs. It was doubtful whether man or beast was
+the more surprised. The cubs began to growl, but their dam gave both
+of them a box on the ears for their bad manners, and led them away. As
+for flowers, the neighborhood of Luchon has the reputation, perhaps
+not undeserved, of being the most flowery part of the Pyrenees.
+
+We went the usual expeditions from the town, in spite of the weather,
+and I will try to remember what plants we noticed in each of them. The
+first trip was to the Vallee du Lys. In spite of the spelling, the
+name suggests lilies of the valley, but we are told that lys is an old
+word meaning water, and that the valley took its name from the number
+of cataracts, not from lilies, there.
+
+However this may be, a lily grows there in great profusion, and was
+just coming into flower toward the middle of June. It is the Lis de
+St. Bruno (Anthericum liliastrum), a plant worthy of giving its name
+to a valley of which it is a characteristic feature. Still more
+conspicuous at the time when we were there were the Narcissus
+poeticus, abundant all round Luchon, but already past in the low
+meadows near the town, but higher up, at an elevation of about 4,000
+ft., it was quite at its best, and whitened the ground over many
+acres.
+
+I looked about for varieties, but failed to detect any special
+character by which it could be referred to any of the varietal names
+given in catalogues, and concluded that it was N. poeticus pure and
+simple. Pulmonarias were abundant along the road, as also in the whole
+region of the Pyrenees, the character of the leaves varying greatly,
+some being spotless, some full of irregular white patches, others with
+well defined round spots. They varied, too, from broad heart-shaped to
+narrow lanceolate, and I soon concluded that it was hopeless to
+attempt any division of the class founded upon the leaves.
+
+Besides the beautiful flowers of Scabious mentioned before, a new
+feature in the meadows here was the abundance of Astrantia major. A
+pure white Hesperis matronalis was also common, but I saw no purple
+forms of it. Geranium phaeum also grew everywhere in the fields, the
+color of the flower varying a good deal. Hepaticas were not so common
+by the roadside here as at Eaux Bonnes, but are generally distributed.
+Many of them have their leaves beautifully marbled, and I selected and
+brought away a few of the best, in hopes that they may keep this
+character. I was struck everywhere by the one-crowned appearance of
+the Hepaticas, as if in their second year from seed.
+
+On the mountains, where they were still in flower, I did not find the
+colors mixed, but on one mountain they would be all white, on another
+all blue. I do not recollect to have seen any pink. Meconopsis
+cambrica is common in the Pyrenees. I observe that in Grenier's
+"French Flora" the color of the flower is given as "jaune orange," but
+I never saw it either in England or in France with orange flowers till
+I saw it covering a bank by the side of the road to the Vallee du Lys.
+I was too much struck by it to delay securing a plant or two, which
+was lucky, for when we returned every flower had been gathered by some
+rival admirers.
+
+Another expedition from Luchon is to the Lac d'Oo. This, too, is
+famous for flowers; but especially so is a high valley called Val
+d'Esquierry, 2,000 ft. or 3,000 ft. above the village d'Oo, at which
+the carriage road ends. Botanists call this the garden of the
+Pyrenees, and, of course, I was most anxious to see it.
+
+The landlord of our hotel was quite enthusiastic in his description of
+the treat in store for me, enumerating a long catalogue of colors, and
+indicating with his hand, palm downward, the height from the ground at
+which I was to expect to see each color. I was afterward told that he
+had never been to the famous valley, being by no means addicted to
+climbing mountains.
+
+During the first part of the drive from Luchon we saw hanging from the
+rocks by the roadside large masses of Saponaria ocymoides, varying
+much in the shade of color of the flowers. This is a plant which I
+find it better to grow from cuttings than from seed. The best shades
+of color are in this way preserved, and the plants are more flowery
+and less straggling. As we got near the end of the carriage road, the
+meadows became more crowded with flowers known in England only in
+gardens.
+
+Besides such plants as Geranium pyrenaicum growing everywhere on the
+banks, the fields were full of a light purple geranium--I think
+sylvaticum. Here, too, I noticed Meconopsis cambrica with orange
+flowers. Narcissus poeticus was also there, and so were some splendid
+thistles, large and rich in color. But the most remarkable part of the
+coloring in the meadows was produced by different shades of Viola
+cornuta carpeting the ground. We noticed this plant in many parts of
+the Pyrenees, but here especially.
+
+From the end of the road I started with a guide for the promised
+garden of the Val d'Esquierry. By the side of the steep and winding
+path I noticed Ramondia pyrenaica--the only place I saw it in the
+Luchon district. Other notable plants were a quantity of Anemone
+alpina of dwarf growth and very large flowers, covering a green knoll
+near a stream. A little beyond, Aster alpinus was in flower, of a
+bright color, which I can never get it to show in gardens. These, with
+the exception of a few saxifrages and daffodils of the variety
+muticus, were about the last flowers I saw there.
+
+[Illustration: GROUP OF ALPINE FLOWERS]
+
+Promise of flowers there was in abundance. Aconites, I suppose
+napellus, and also that form of A. lycoctonum with the large leaves
+known as pyrenaicum, were just enough grown to recognize. The large
+white Asphodel, called by French botanists A. albus, but better known
+in gardens as A. ramosus, which grows everywhere in the Pyrenees, and
+the coarse shoots of Gentiana lutea were just showing.
+
+Further on the daffodils were only just putting their noses through
+the yellow dead grass, which the snow had hardly left and was again
+beginning to whiten, for the rain, which had been coming down in
+torrents ever since I left the carriage and had wet me through, had
+now changed to snow. Still I went on, in spite of the bitter cold,
+hoping that I should come to some hyperborean region where the flowers
+would be all bright; but my guide at last undeceived me, and convinced
+me that we were far too early, so we went down again, wiser and
+sadder, and I advise my friends who wish to see the Val d'Esquierry in
+its beauty not to visit it before July at the earliest.
+
+I have still one mountain walk to describe, a far more successful one,
+but it must be deferred till another week.--_C. Wolley Dod, in the
+Garden._
+
+       *       *       *       *       *
+
+
+Turtle shells may be softened by hot water, and if compressed in this
+state by screws in iron or brass moulds, may be bent into any shape,
+the moulds being then plunged into cold water.
+
+       *       *       *       *       *
+
+
+
+
+A CENTURY PLANT IN BLOOM.
+
+
+A huge agave, or century plant, is now blooming at Auburn, N.Y. A few
+days ago the great plant became tinged with a delicate yellowish-white
+color, as its 4,000 buds began to develop into the full-blown flowers,
+whose penetrating fragrance, not unlike that of the pond lily, now
+attracts swarms of bees and other insects. The plant was purchased in
+1837 by the owner, and was then twelve years old. For half a century
+the agave has lain around his greenhouses in company with several
+others, and no special care has been taken of it, except to protect it
+somehow in winter, that it might be fresh for the next summer's
+growth. The plant has always been a hardy specimen, and required
+little care. Its whole life, now speedily approaching a termination in
+the fulfillment of the end of its existence--flowering--has been a
+sluggish course. Its growth has been steady and its development
+gradual. Occasionally it has thrust out a spiked leaf until, in size,
+it became greater than its fellow plants and took on the likeness of
+an enormous cabbage which had been arrested in its development and
+failed to attain perfection. Early last April its appearance began to
+undergo a decided change. Its resemblance to a cabbage lessened, and
+it began to look like a giant asparagus plant. On April 12, the great
+fleshy leaves, massed together so as to impress the imprint of their
+spines upon one another, began to unfold, and a thick, succulent bud
+burst up amid the leaves. Slowly the stalk developed from the bud and
+assumed gigantic proportions. Green scales appeared in regular
+arrangement about the stalk, marking the points from which lateral
+branches were to spring. The thick stalk, tender and brittle at first
+as new asparagus, became tough and hard enough to resist a knife, and
+its surface assumed the gritty character of the leaves of the plant.
+The low roof of the hothouse became an obstruction to further growth,
+and had to be removed. Lateral limbs were, at a later period, thrust
+out in great numbers, each of them bearing small branches, as do
+strawberry plants, on which hang sprays of buds in bunches of from
+three to ten, making in all many hundreds, all waiting for the
+completion and blooming of the topmost buds. The inflorescence of the
+century plant is peculiar, and the appearance of flowers on the lower
+branches may be simultaneous with, or consecutive to, the blossoming
+on the upper limbs. With the appearance of the lateral outshoots the
+great aloe lost its likeness to asparagus, and at present bears
+resemblance to an immense candelabra. The plant is now fully matured,
+and has a height of twenty-seven feet. There are thirty-three branches
+on the main stem, and, by actual count, one of the lateral limbs was
+found to bear 273 perfect buds, some of whose green sepals have
+spread, revealing the yellowish-white petals and essential parts of
+the plant. The ample panicles crowded with curious blossoms are, as,
+indeed, the Greek name of the plant--agave--signifies, wonderful.
+
+There is a pathetic view to be taken of the great plant's present
+condition. For years it has been preparing to flower, and the shoot it
+has sent up is the dying effort. The blossoms carry in them the life
+of new plants, and the old plant dies in giving them birth. It is
+commonly supposed that this plant, the _Agave Americana_, or American
+aloe, blooms only at the end of 100 years, hence the common name
+century plant.
+
+Only two plants are on record among the floriculturists as having
+bloomed in New York State. Thirty years ago, a century plant, of which
+the Casey aloe was a slip, flowered in the greenhouses of the Van
+Rensselaer family at Albany. In 1869, a second plant blossomed at
+Rochester. At present, two aloes, one at Albany, the other at
+Brooklyn, are reported as giving evidences of approaching maturity.
+They are pronounced not American aloes, or century plants, but _Agave
+Virginica_, a plant of the same family commonly found in sterile soil
+from Virginia to Illinois and south, and blossoming much more
+frequently. In Mexico the century plant is turned to practical account
+and made a profitable investment to its owners. After the scape has
+reached its full growth it is hewn down, and the sap, which fills the
+hollow at its base, is ladled out and converted by fermentation into
+"agave wine," or "pulque," the favorite drink of the Mexicans. This
+pulque, or octli, has an acid resembling that of cider, and a very
+disagreeable odor, but the taste is cooling and refreshing. A brandy
+distilled from pulque is called "aquardiente," or "mexical." The
+plant, by tapping, can be made to yield a quart of sap daily. The
+fibers of the leaves when dried furnish a coarse thread known as Pita
+flax, and when green are used in Mexico as fodder for cattle. Razor
+strops or hones are also made from the leaves, which contain an
+abundance of silica and give rise to a very sharp edge on a knife
+applied with friction across the surface of the dried leaf.
+
+       *       *       *       *       *
+
+
+
+
+CREOSOTE A SPECIFIC FOR ERYSIPELAS.
+
+
+Time was when the advocate of a specific was laughed at by the
+scientific world, but since it is known that so many forms of disease
+are the direct result of some kind of germ life, it is no longer a
+misnomer to call a medicine which will certainly and always destroy
+the germ which produces so many forms of disease a specific.
+
+In the light of this definition, founded upon the experience of forty
+years' successful practice in treating this form of disease with
+creosote, the writer is prepared to indorse the heading of this
+article. Having used all the different remedies ordinarily prescribed,
+they have long since been laid aside, and this one used in all forms
+of the disease exclusively, and with uniform success.
+
+In 1863 it was the writer's fortune to spend several weeks in a
+military hospital in Memphis as a volunteer surgeon, under the
+direction of Dr. Lord. In conversation with him, the use of this
+article was mentioned, which appeared new to him, and a case was put
+under treatment with it, with such prompt favorable results as to
+elicit his hearty commendation, and, at his suggestion,
+Surgeon-General Hammond was informed of it.
+
+All injuries, of whatever kind, have been treated with dressings of
+this remedy, and where this has been done from the first to last, in
+no instance has there been an attack of erysipelas.
+
+The usual manner of application was in solution of six to twenty drops
+to the ounce of water, keeping the parts covered with cloths
+constantly wet with it. In ulcers or wounds it may be used in the form
+of a poultice, by stirring ground elm into the solution, the strength
+to be regulated according to the virulence of the attack. Ordinarily,
+ten drops to the ounce is strong enough for the cutaneous form of the
+disease and in dressings for wounds or recent injuries. If the
+inflammation threatens to spread rapidly, it should be increased to
+twenty or more drops to the ounce of water.
+
+The antiseptic properties of this remedy render it of additional
+value, as it will certainly destroy the tendency to unhealthy
+suppuration, and thus prevent septicaemia.
+
+In the treatment of hundreds of cases of erysipelas but one fatal case
+has occurred, and that one in an old and depraved system. In the less
+violent attacks no other remedy was used, but where constitutional
+treatment was indicated, the usual appropriate tonics were prescribed.
+
+There is no question in my mind but that creosote is as much a
+specific in erysipelas as quinine is in intermittent fever, and may be
+used with as much confidence.--_St. Louis Med. Jour._
+
+       *       *       *       *       *
+
+
+
+
+A NEW APPARATUS FOR THE STUDY OF CARDIAC DRUGS.
+
+By WILLIAM GILMAN THOMPSON, M.D., New York.
+
+
+The apparatus was devised by Mr. R.D. Gray (the inventor of the
+ingenious "vest camera" and other photographic improvements) and by
+myself. I described what was required and suggested various
+modifications and improvements, but the mechanical details were worked
+out exclusively by him. To test the rapidity of the camera, we
+photographed a "horse-timer" clock, with a dial marking quarter
+seconds, and succeeded in taking five distinct photographs in half a
+second with _one_ lens, which has never before been accomplished
+excepting by Professor Marey,[1] at the College de France, who has
+taken successive views of flying birds, falling balls, etc., with one
+lens at a very rapid rate. His camera was unknown to me until after
+mine was constructed, so that as a success in photography alone the
+work is interesting.
+
+  [Footnote 1: La Methode Graphique (Supplement), Paris, 1885.]
+
+The camera consists of a circular brass box, 51/2 inches in diameter and
+11/4 inches deep, containing a circular vulcanite shutter with two
+apertures, behind which is placed a circular dry plate. Both plate and
+shutter are revolved in opposite directions to each other by a simple
+arrangement of four cogged wheels moved by a single crank. The box is
+perforated at one side by a circular opening, 13/4 inches in diameter,
+from the margin of which projects at a right angle a long brass tube
+(Fig. 1), which carries the lens. In Fig. 2 the lid of the box has
+been removed, and the bottom of the box, with the wheels, springs, and
+partially closed shutter, is presented. The lid is double--that is, it
+is a flat box in itself. It contains nothing but the dry plate,
+supported at its center upon a small brass disk, against which disk it
+is firmly pressed by a pivot attached to a spring fastened in the lid.
+The aperture in one side of this double lid, which corresponds with
+that seen in the floor of the box, may be closed by a slide, so that
+the lid containing the plate can be removed like an ordinary plate
+holder and carried to a dark room, where it is opened and the plate is
+changed. When the lid is replaced this slide is removed, and as the
+shutter is made to revolve, the light falls upon whatever portion of
+the dry plate happens to be opposite the opening.
+
+By reference to Fig. 2, it will be seen that when the large wheel
+which projects outside of the box is revolved by a crank, it turns the
+small ratchet wheel, which bears an eccentric pawl. (The crank has
+been removed in Fig. 2; it is seen in Fig. 1.) The central wheel has
+only six cogs. The pawl is pressed into one of these cogs by a spring.
+It pushes the central wheel around one-sixth of its circumference,
+when it returns to be pressed into the next cog. While the pawl
+returns, it necessarily leaves the central wheel at rest, and whatever
+momentum this wheel carries is checked by a simple stop pressed by a
+spring upon the opposite side. The central wheel carries a square
+axle, which projects through a small hole in the center of the double
+lid and fits into the brass disk before alluded to, causing the disk
+to revolve with the axle. The disk is covered by rubber cloth; and as
+the dry plate is pressed firmly against the rubber surface by the
+spring in the lid, the plate adheres to the rubber and revolves with
+the disk. Thus every complete revolution of the central wheel in the
+floor of the box carries with it the dry plate, stops it, and moves it
+on again six times. The velocity of revolution of the plate is only
+limited by the rapidity with which one can turn the crank.
+
+The shutter is revolved in the opposite direction by a wheel whose
+cogs are seen fitting into those of the little wheel carrying the
+eccentric pawl.
+
+[Illustration: FIG. 1.--THE CAMERA MOUNTED.]
+
+The two apertures in the shutter are so placed that at the instant of
+exposure of the plate it is momentarily at rest, while the plate when
+moving is covered by the shutters. This arrangement prevents vibration
+of the plate and blurring of the image. The camera is mounted by two
+lateral axles with screw clamps upon two iron stands, such as are in
+common use in chemical laboratories. A brass rod attached to the tube
+steadies it, and allows it to be screwed fast at any angle
+corresponding to the angle at which the heart is placed. It is thus
+easy to put a manometer tube in the femoral artery of an animal, bend
+it up alongside of the exposed heart, and simultaneously photograph
+the cardiac contraction and the degree of rise of the fluid in the
+manometer(!). The tube is arranged like the draw tube of a microscope.
+It is made long, so as to admit of taking small hearts at life-size.
+The stand carries a support for the frog or other animal to be
+experimented upon, and a bottle of physiological salt solution kept
+warm by a spirit lamp beneath.
+
+[Illustration: FIG. 2.--INTERIOR OF THE CAMERA.]
+
+The whole apparatus is readily packed in a small space. I have already
+taken a number of photographs of various hearts and intestines with
+it, and the contraction of the heart of the frog produced by
+_Strophanthus hispidus_, the new cardiac stimulant, is seen in Fig. 3,
+taken by this new instrument. The apparatus has the great advantage
+that six photographs of a single cardiac pulsation, or of any muscular
+contraction, may be easily taken in less than one second, or, by
+simply turning the crank slower, they may be taken at any desired rate
+to keep pace with the rhythm of the heart. The second hand of a watch
+may be placed in the field of view and simultaneously photographed
+with the heart, so that there can be no question about the series of
+photographs all belonging to one pulsation.
+
+[Illustration: FIG. 3.--PHOTOGRAPHS OF THE HEART IN MOTION.
+
+1, Normal diastole; 2, auricular systole; 3, ventricular systole. 1,
+2, 3 were taken in a half second; 4, 5, 6, same as 1, 2, 3, after
+injection of toxic dose of Strophanthus hispidus. 4, 5, 6 were taken
+in a half second. The pulse rate was 74.]
+
+I have already called attention[13] to the ease with which these
+photographs are enlarged for lecture room demonstration, either on
+paper or in a stereopticon, and the ease with which they may be
+reproduced in print to illustrate the action of drugs.
+
+[Footnote 13: _Medical Record_, loc. cit.; Recent Advances in Methods
+of Studying the Heart, _Medical Press_, Buffalo, March 1, 1886, p.
+234; Instantaneous Photographs of the Heart, Johns Hopkins University
+Circulars, March, 1886, p. 60.]
+
+       *       *       *       *       *
+
+
+A CATALOGUE containing brief notices of many important scientific
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+End of the Project Gutenberg EBook of Scientific American Supplement, No.
+561, October 2, 1886, by Various
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