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Scientific American Supplement, No. 601, July 9, 1887
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SCIENTIFIC AMERICAN SUPPLEMENT NO. 601



NEW YORK, JULY 9, 1887

Scientific American Supplement. Vol. XXIV, No. 601.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

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TABLE OF CONTENTS.

I. ASTRONOMY.—A Star Finder.—A simple apparatus that can be constructed by any mechanic.—1 illustration.

Photographic Study of Stellar Spectra, Harvard College Observatory. —First annual report of the Henry Draper memorial observations. —Review of the work by Prof. EDWARD C. PICKERING.

II. BIOLOGY.—Sponges.—The growth and life history of sponges.—Report of a recent lecture at the London Royal Institution by Dr. R. VON LEDENFELD.

III. ELECTRICITY.—Phenomena of Alternating Currents.—By Prof. ELIHU THOMSON.—16 illustrations.

IV. ENGINEERING.—An English Car Coupling.—Description of an English automatic coupling.—2 illustrations.

A New Process of Casting Iron and other Metals upon Lace, Embroideries, Fern Leaves, and other Combustible Materials. —By A.E. OUTERBRIDGE, JR.—A new and eminently practical process of producing ornamental castings.—4 illustrations.

Bricks and Brick Work.—By Prof. T. ROGER SMITH, F.R.I.B.A. —The history and technical review of this subject.—A most remarkable contribution to the engineering of architecture.

Link Belting.—By CHARLES A. SCHIEREN.—An interesting and practical paper on leather belting made of links. —9 illustrations.

Recent Progress in Gas Engineering.—A lecture by Mr. A. MACPHERSON, of Kirkcaldy, reviewing the last improvements in this branch.

V. MISCELLANEOUS.—Herbet's Tepid Douche.—Apparatus in use for bathing soldiers in the French barracks.—1 illustration.

Kent's Torsion Balance.—A new type of balance, involving torsional suspension instead of knife edges.—5 illustrations.

Preservative Liquid.—Note on preservation of organic substances.

The Falls of Gairsoppa.—The great Indian falls, higher than Niagara.—2 illustrations.

The New British Coinage and Jubilee Medal.—Illustrations and descriptions of the new pieces.—8 illustrations.

The Winner of the Derby.—Portrait and description of Merry Hampton.

VI. NAVAL ENGINEERING.—The Falke Type Torpedo Boat.—The fastest type of British torpedo boat, constructed by Messrs. Yarrow & Co.—1 illustration.

The German Navy.—The New Gunboat Eber.—A description of a late accession to the German navy.—1 illustration.

VII. ORDNANCE AND GUNNERY.—Magazine Rifles.—Continuation of this important article, including the Chaffee-Reece, Kropatschek, and other magazine guns.—3 illustrations.

New British Torpedo Experiments.—Experiments with torpedoes against a ship.—The efficiency or torpedo nets.—The effects of Whitehead torpedoes.

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THE FALKE TYPE TORPEDO BOAT.

Among the different classes of vessels designed for special services, constructed by Messrs. Yarrow & Co., at Poplar, for the British government, is one which is stated to be the fastest torpedo boat in her majesty's navy. This boat has been put through its official trials; with a load of 15 tons, running continuously for two hours without stopping, a speed of 23 knots, which is equal to 261/2 statute miles, an hour was obtained. The boat is 135 ft. long by 14 ft. beam. Its design is known as the Falke type, being in many respects similar, but very superior, to a torpedo boat of that name which was built two years ago by the same firm for the Austrian government. The form of the hull is of such a character as to give exceptional steering capabilities; at the time of trial it was found to be able to steer round in a circle of a diameter of 100 yards, averaging 62 seconds. The forward part of the boat is completely covered over by a large turtle back, which is the customary form of the boats built by Messrs. Yarrow & Co. It was first introduced in the Batoum, which they constructed eight years ago for the Russian government. This turtle back increases the seaworthiness of the craft by throwing the water that comes upon it freely away. It forms, also, good and roomy accommodation for the crew, and incloses a large portion of the torpedo apparatus. The forward torpedo gear consists of one torpedo gun, adapted for ejecting the Whitehead torpedo by means of gunpowder, now preferred on account of its simplicity. The boiler, one of Messrs. Yarrow & Co.'s special construction, of a type which has undergone many years of constant trial, is capable of developing 1,660 horse power. In the engine room there are six engines—one for driving the boat, two for compressing the air for the torpedoes, an engine for working the dynamo for producing the electric light, an engine for forcing air into the stoke-hole, and an engine working in conjunction with the distilling apparatus for supplying drinking water for the crew and the waste incidental to the boiler. Aft of the engine room come the officers' quarters. The stern of the boat is fitted up as a pantry and for the stowage of ammunition and stores. On the deck are mounted three machine guns, and near the stern an additional conning tower for use in case of need, around which revolve two torpedo guns for firing the torpedoes off either side. These torpedo guns can be trained to any angle it may be desired to fire them at. On both conning towers are machine guns.—Illustrated London News.



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THE GERMAN NAVY—THE NEW GUNBOAT EBER.

The gunboat Eber is an improved vessel of the Wolf type, but differs from other vessels of its class in that it has not a complete iron hull, only the frame and deck beams being of iron, while the planking is of wood and yellow metal. No copper is used on the bottom. The "composite system" of building is looked upon with favor for ships of this kind, because iron vessels which are kept permanently at stations in the tropics soon become overgrown in spite of good care, and thus suffer a great loss of speed. In a wooden vessel the crew's quarters are better and more healthful than in iron vessels, for they are not as much affected by the temperature outside of the ship.

The greatest length of the Eber is about 245 ft.; its breadth, 26 ft.; its depth, 14 ft.; and it has a displacement of about 500 tons. The armament will consist of three long 5 in. guns in center pivot carriages, and a small number of revolvers. One of the former will be placed at the stern on the quarter deck, and the two others on the forecastle. Some of the revolvers will be on the quarter deck and some on the forecastle, care being taken to arrange the guns so as to obtain the widest possible range, thus enabling the ship to protect itself perfectly.



The Eber is provided with a two-cylinder, compound engine, which can generate 650 horse power, giving the vessel a speed of 111/2 knots. The coal bunkers are so large that the ship can travel 3,000 miles at a speed slightly less than that just mentioned without requiring a fresh supply of coal. The rigging is the same as in iron vessels of the Wolf class, and the sails are sufficiently large to allow the vessel to proceed without steam. The ship will carry about 90 men, including officers, crew, engineers, and firemen.

A sum of $145,000 was appropriated for the construction and equipment of the Eber, which was begun at Kiel in the latter part of 1885, and was launched February 15, 1887.—Illustrirte Zeitung.

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NEW BRITISH TORPEDO EXPERIMENTS.

The torpedo experiments against the Resistance, which have been suspended since November last, were resumed on June 9 at Portsmouth by the officers of the Vernon. The injuries received by the ironclad in the previous experiments having been repaired, so as to make the vessel watertight, the old ship was towed up the harbor, and moored in Fareham Creek. Our readers are aware that the Resistance is an obsolete ironclad which has finished her career as a battle ship, and that nothing could have converted her into a modern armorclad.

Although it was intended to render the experiments final and conclusive as a practical demonstration under service conditions of the destructive effects of the Whitehead torpedo when directed against a modern vessel of war, the results still leave behind them much uncertainty. The Resistance was built of iron, whereas battle ships are now exclusively constructed of steel, and it would be perhaps hazardous to state that the behavior of the two metals under a sudden and violent shock would be exactly the same. The construction of the double bottom of the old ship is also different. Since the last experiments were carried out against her, however, measures have been taken to make her as far as possible the counterpart, so far as under water arrangements and coal protection are concerned, of a modern ship of war.

At the last attack, the Whitehead was directed against the after part of the hull on the port side in wake of the boilers. During the present series of experiments the old ship was assailed on the same side, but directly amidships, in the neighborhood of the engine room. As no steam was got up in the boilers, the effect of the jar upon the steam pipes, glands, and feed connections remains a matter of speculation. So far as the consequences of the burst upon the structure of the hull itself is concerned, every care was taken to make the ordeal as complete and instructive as possible. The wing passage, which has a maximum diameter of 3 ft. diminishing to a point, was left empty, although at the former experiments the lower portions were filled with coal. But behind this, and at a distance of 8 ft. from the bulkhead, a longitudinal or fore and aft steel bulkhead 3/8 in. thick had been worked to a length of 61 ft., and, with the coal with which the intervening compartment was packed, formed (as in recent armorclads) a solid rampart, 20 ft. high, for the defense of the engine room.

The height of the double bottom between the outer and inner skin plating is 21/2 ft. The watertight compartments were divided into stations by means of vertical lightening plates pierced by three holes, and in order to make them, as far as was practicable, resemble the bracket frames of a modern armorclad, the center of the plates was cut away so as to leave a single oval hole instead of the three circular holes. In view of the differences of opinion which exist on the part of experts on the subject of under water protection, the officers of the Vernon had determined to submit the problem to the test of experiment. For this purpose steel armor 11/2 in. thick had been worked along the outside of the upper skin of the double bottom throughout one of the compartments, in addition to the other protection mentioned. The Resistance had been brought down by iron ballast to a trim of 25 feet 9 in. aft and 19 ft. 7 in. forward, giving a mean draught of 22 feet 8 inches. She was consequently rather further down by the stern than before, but was in other respects the same.

When in commission, the Resistance had a mean draught of 26 feet 10 inches. The present series of experiments was of even greater importance than the first series. The attack was gradually developed by means of fixed and outrigger charges of increasing power, and the coup de grace was not given by means of a service Whitehead in actual contact until various lessons had been derived.

The opening experiment on June 9 consisted of an attack directed against a new system of torpedo defenses which are to be carried by ships in action, or when in expectation of an attack, rather than an assault upon the ship herself. The previous experiments had clearly demonstrated that a Whitehead, when projected against a vessel at close range, and consequently with a maximum of motive force, could not get through the ordinary wire netting before expending its explosive energy in the air, and that the spars by which the nets are boomed out from the ship's side could be reduced to 25 ft. in length without danger to the hull. The ordinary wooden booms employed on board ship, however, are heavy and unwieldy, weighing, as they do, more than half a ton each. In ordinary circumstances, the spars cannot be lowered into place and the nets made taut in less than a couple of hours, and the work of stowing them is equally slow and laborious.

Mr. Bullivant, who manufactures the torpedo netting and hawsers for the navy, has devised a method of getting rid of the difficulties complained of by substituting steel booms for the wooden booms and an arrangement of pulleys and runners, whereby the protection can be run out and in, topped and brailed up out of the way, with great facility. The system was tried at Portsmouth last year with considerable success upon the Dido, but as it was thought that some of the fittings were somewhat frail and might collapse beneath the shock of a live torpedo, it was resolved to submit them to a practical test under service conditions upon the Resistance. The ship was consequently fitted with three of the steel booms on the port side. They were 32 ft. long and spaced 45 ft. apart, and connected by a jackstay to which the nets were attached. Each steel boom weighed 5 cwt., or less than half the weight of the ordinary boom, and whereas the latter is fixed to the ship's side by a hook which is liable to be disconnected or broken by the jerk of an exploding torpedo, Mr. Bullivant's boom works in a universal or socket joint, which cannot get out of gear except by fracture, and which permits the boom to be moved in any direction, whether vertically or fore and aft, close in against the sides. Below each boom is a flange, which serves as a line along which a traveler moves, the latter being actuated by means of a topping line running over a pulley at the head and another near the heel.

Upon the booms being topped to a perpendicular position, the nets are attached to the runners at the bottom of the booms close inboard (instead of, under the existing system, to the tops of the booms from boats alongside or otherwise), and when this is done, the mere depression of the booms into position will cause the nets to run out of their own accord. In like manner, when the occasion for their use has passed, the raising of the boom will cause the nets to come alongside, when they can either be brailed up through the grummets or disconnected for future use.

The action of the gear is so simple and rapid that the torpedo protection can be always ready without arresting the way of the ship. As a length of net 30 ft. by 20 ft. deep weighs about 3 cwt., it will also be seen that the reduction of strains by working the crinolines from the heel instead of the head of the booms is considerable. The attack by the Whitehead upon the booms and nettings was made shortly before 2 p.m., at the time of high tide.

The whole affair occupied a very few minutes. As soon as the red pennant was struck on board to show that Mr. Bullivant was satisfied with the arrangements, and that the target was ready, the torpedo vessel Vesuvius got under way, and after circling round the doomed hulk discharged a Whitehead against the netting from her under-water bow torpedo tube at an approximate range of 50 yards. As on former occasions, the missile was one of the old 16 inch pattern, but it was understood that the charge of gun cotton had been reduced to 87 lb., so that the net protection should not bear a greater strain than would be the case in actual hostilities. The torpedo, which was set to a depth of about 10 feet, struck the net in the middle and threw up an immense spout of water, but without getting to the ship, which was apparently uninjured. Although it hit the net immediately below the center boom, no fracture occurred, and the points remained intact. Although at the short range the torpedo would spin through the water at from 30 to 40 horse power, and would deliver a formidable blow upon the net, the thrust was effectually resisted, though as a matter of course the net was much torn by the explosion of the baffled projectile.

Although at the second torpedo attack made on the Resistance, the following day, the offensive power that was brought to bear was quite exceptional, the victory remained with the ship. The charge exploded was an exceptionally heavy one. It consisted of 220 lb. of gun cotton. It was consequently more destructive than any which is ever likely to be launched against an armorclad much better prepared to resist it than the obsolete and time-worn Resistance. An idea, however, had got abroad that the Russians either have or intend to have a locomotive torpedo capable of carrying the same weight of explosive in its head, and the object of the experiment was to ascertain what would be the effect of the detonation of such an enormous charge upon the submerged portions of a ship of war.

But, while this was no doubt the primary purpose in view, the experiment also served the secondary purpose of determining the result of the explosion upon the net defenses of a ship. Mr. Bullivant's booms and runners, which were found to be scarcely anything the worse from the ordeal of the previous day, were again used. The damaged net was taken away and one of the old service grummet nets slung in its place, the cylinders containing the gun cotton being attached to the jackstay immediately in front of the battered sides, and 30 feet from the hulk, and sunk to a distance of 20 feet below the water line, which would bring it about opposite the bend of the bilge. By 3 p.m. everything was ready for the explosion of the charge—everybody had cleared out of the ship while the surrounding small craft drew off to a distance of 300 feet. The charge was electrically fired from a pinnace. The burst was terrific and the reverberation was heard and the shock distinctly felt in the dockyard. But the remarkable thing was that the hulk did not appear to jump in the least, though there was not more than six feet of water under her keel. That she would not be seriously crippled by the discharge seems to have been accepted as a foregone conclusion by Captain Long and the other torpedoists, as the day for the third experiment had been fixed in advance; but that the steel booms with their double flange running ways, stays, travelers, and hinges should have resisted the tremendous jar and upheaval was a genuine surprise for all concerned, and goes far to prove that except a vessel be taken unawares, it will be impossible for a torpedo to come into actual contact with it. At the experiments last year the wooden booms were unhinged and splintered under a much less violent shock. But the steel booms employed, though somewhat bent, remained unbroken and in position, and the joints were quite uninjured. All that is necessary for perfect defense is that the booms should be made a little heavier.

The torpedo experiments against the Resistance were resumed on June 13, when the old ironclad suffered some rough treatment. As the experiment was understood to be the last of the second series, and was fully expected to have a sensational termination, a considerable number of interested spectators were attracted to the scene in Fareham Creek. The torpedoists resorted to severe measures, but with a distinctly useful purpose in view, having bound the ship hand and foot, so to speak, in such a way that her name became a solecism. They exploded 95 lb. of gun cotton 20 ft. below the water, and in contact with her double bottom. This amount of explosive represents the full charge of the old pattern 16 in. Whiteheads; but as the hulk was, for prudential reasons, moored close to a mud bank, and as the water was consequently much too shallow to allow of a locomotive torpedo being set to run at the required depth, a fixed charge was lashed fore and aft against the bottom plating of the ship and electrically exploded from No. 95 torpedo boat.

In previous experiments this year the ironclad was attacked on the port side, which had been specially strengthened for the occasion, and the result was a victory for the defense. On June 13 the starboard side was selected for attack, in order that a comparison might be instituted with the effects produced under different conditions by a similar experiment.

Last year in the latter case the double bottom was filled with coal; and after the charge, which was lashed against the ship in the same way, had been exploded, it was found that the bilge keel had been shivered for a length of 20 ft., while the lower plating had been much bulged above the bilge keel. Four strakes of the skin plating extending up to the armor shelf had also been forced inward and fractured where they crossed the longitudinal frames. They had parted in the middle for a distance of 8 ft., while some of the butts had been opened so that gashes 2 in. or 3 in. wide appeared between them. The coal had been pulverized and scattered in all directions, and other internal damage inflicted. Nevertheless, the watertight bulkheads remained intact, and by confining the influx of water to a single compartment so much buoyancy was preserved that, though the ship heeled over to starboard and was maimed, she remained afloat, and might have continued to fight her guns, provided always that no injury had been sustained by her machinery, a point which these experiments do not touch. Crippled, however, as she was, it was thought at the time (and the probability was strengthened by subsequent examination of the ship in dock) that the coal, instead of being a protection to the double bottom, had in reality proved a source of weakness by receiving the energy of the explosion from the outer plating and communicating it to the inner plating, and so distributing it throughout the submerged portions of the hulk.

The question was sufficiently important to demand an experimental solution; hence the raison d'etre of the present demonstration. The double bottom, which is about 21/2 ft. deep, was consequently kept empty, and the torpedo placed in immediate contact with it in such a manner that, being overhung by the contour of the hull, the ship would feel the full force of the upward as well as the lateral energy of the charge. On other accounts the importance of the experiment was obvious, for, although it had been ascertained that torpedo nets were capable of protecting a battle ship from the bursts of the heaviest locomotive and outrigger charges, it might happen, of course, that the nets would be rent or displaced by shell fire or swept away by a grazing ram or even attacked by a double torpedo, the second passing through the gashes made by the explosion of the first in any case. It was, therefore, of urgent necessity that the effect of a torpedo bursting in immediate contact with a ship's bottom should be practically and clearly determined. The charge on June 13 was fired just before 5 p.m. in the wake of the boilers, and it was soon perceived that something of a fatal character had taken place from the appearance of coal dust sweeping up through the hold. The report had not the dull boom to which the spectators had become accustomed. Instead of this, the gun cotton exploded with a sharp, angry, whistling noise, while the manner in which the mud was churned up showed that the force of the rebound was terrific. The ship lifted bodily near the stern, after which it was seen to leisurely heel over to starboard some eight or ten degrees, and finally repose, though not until the tide fell, upon the mud. The old hulk had been mortally wounded at last.

A complete knowledge of the disaster which has overtaken her (says the correspondent of the London Times, to which we are indebted for the above particulars) will not be obtained until a careful investigation has been made of the hull in dock. But, from a hasty exploration which was conducted on board, it was evident that the shot had not only dislocated the inner plating of the double bottom, but had penetrated the bunker compartment, stored as it was with coal, that the watertight doors and compartments had ceased to operate, and that water was flowing into the hull through a hundred crevices. To such an extent was this the case that, though a strong working party was at hand ready for any emergency, it was deemed useless to attempt to free the ship of water until her gashes had been temporarily closed from outside. When this has been done, she will be pumped out and brought into dock for careful examination. From what has been said, it will be seen that while the explosion of 95 lb. of gun cotton in actual contact last November simply crippled the Resistance, the explosion of a like charge at the same spot, and under approximately the same conditions, has in this instance not simply disabled, but really sunk the ship.

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AN ENGLISH CAR COUPLING.

The new automatic railway coupling illustrated below is the invention of Mr. Richard Hill, and has been practically developed by Mr. B.H. Thwaite, of Liverpool. It will be seen that the system is somewhat similar to the parallel motion when in action.

The catch and peculiarly shaped hooks slide over the cross and catch bars. These latter turn horizontally on a central pivot attached to the jaw end of the drawbar. The cross catch bars adjust themselves to the direction of the line of pull in the drawbar. The cranking of the drawbar allows for the deflection of the buffer springs.

The arrangement of uncoupling, or throwing hooks out of gear, is extremely simple and effective. The cranked part of the rod passing across the end of the wagon, and with handles at each end workable from the 6 ft. way, is attached to the catch hooks by means of a light chain. On throwing the handle over, and against the end of the wagon, the crank moves over and below the center, lifting up the catch into a position out of range of action, and from this position it cannot fall except it is released by the shunter. A shackle and links hang from the end of the drawbar for attachment to ordinary wagons.

After a long and costly series of experiments the form of coupling shown in illustration was adopted. Part of the experimental couplings used were made by the Hadfield Steel Foundry Company, but the couplings used at a recent trial at Gloucester were forged by the Gloucester Wagon Company.



The trial couplings were applied to old and worn-out coal wagons, varying in relative heights and widths of buffers, and the tests were:

1. Coupling and uncoupling, and passing coupled round curves of less than two chains radius. 2. Coupling under rapid transit movement and violent shock. 3. Coupling under slow movement, the wagons being shunted together by two shunters. 4. Wagons brought violently together while the coupling hooks were lifted out of action, to test the rigidity of the hooks in this position. 5. Tested in competition with the ordinary coupling stock.

The trial was a success. The new automatic coupling satisfactorily underwent the various conditions, and it was proved that: 1. It can be lifted out of action with one hand and quite easily. 2. It can be coupled and uncoupled six times as fast as with the pole hook in the daytime. At night this advantage would be considerably increased.

The coupling is strong as well as elastic in its parts, and adjusts itself to the various conditions of traction.—Engineering.

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[Continued from SUPPLEMENT, No. 597, page 9539.]



MAGAZINE RIFLES.

Chaffee-Reece Magazine Rifle.—We do not insert a drawing of this arm—one of the three selected by the American board—as it belongs to the same class and is similar in general construction to the Hotchkiss. There is, however, an important difference in the magazine, which has no spiral spring, but is furnished instead with an ingenious system of ratchet bars. One of these carries forward the cartridge a distance equal to its own length at each reciprocal motion of the bolt, while a second bar has no longitudinal motion, but prevents the cartridges from moving to the rear in the magazine tube after they have been moved forward by the other bar. The magazine is loaded through an aperture in the butt plate, the opening of the spring cover of which causes the two ratchet bars to be depressed, so that the magazine can be filled by passing the cartridges along a smooth middle bar. The act of closing the spring cover again brings the two ratchet bars into play.



By means of a cut-off the ratchet bars can be prevented from acting, and the piece used as a single loader.

Kropatschek Magazine Rifle.—This rifle, which is the small arm of the French navy, has a bolt-action rifle resembling the Gras (see Fig. 9).

The magazine is a brass tube underneath the barrel, as in the Winchester, Vetterli, Mauser, and other rifles of class 1. It contains six cartridges, while a seventh can be placed in the trough or carrier, T.

When the breech is opened by pulling back the bolt, a projection on the latter strikes the carrier at N, causing its front extremity to raise the cartridge into the position shown in the section. This movement is accelerated by the spring, A, acting against a knife-edge projection on the trough, T; in the upper position of the trough, the spring acts upon one face of the angle, and upon the other face when in the lower position.

On closing the breech, the bolt pushes the cartridge into the chamber, and when the handle is locked down to the right, a part of the bolt presses against a stud, and thus depresses the trough to be ready to receive another cartridge from the magazine.

The magazine can be cut off and the rifle used as a single loader by pushing forward a thumb-piece on the right side of the shoe. The effect of this is that, on turning down the handle to lock the bolt, the latter does not act on the stud to depress the carrier, so that no fresh cartridges are fed up from the magazine.



There is a projection, Z, on the fore part of the carrier, which keeps the next cartridge from leaving the magazine while the trough is in the upper or loading position. A supplementary cartridge stop, R, pivoted at P and having a spring, L, underneath it, acts in conjunction with Z in retaining the cartridges in the magazine, and especially in preventing more than one at a time from passing out into the carrier when the latter is depressed; it also retains the cartridges in the magazine tube while the latter is being filled.

Lee Magazine Rifle.—This arm (see Fig. 10), which occupied the place of honor in the report of the American "Board on Magazine Guns," embodied two new principles of considerable importance, viz., the central position of the magazine, and having it detachable with ease, so that two or more magazines can be carried by the soldier.

The breech action of the Lee does not materially differ in design from other bolt rifles, except that the bolt is in two pieces only—the body, or bolt proper, and the hammer or cocking-piece. The firing pin, or striker, is screwed into the hammer; the spiral main spring, which surrounds the striker, is contained in a hollow in the body. The handle is placed at the rear end of the bolt, and bent down toward the stock, so as to allow the trigger to be reached without wholly quitting hold of the bolt. The extractor is so connected with the bolt head as not to share the rotation of the latter when the handle is turned down into the locking position. When the handle is turned up to unlock the bolt, the hammer is cammed slightly to the rear, by means of oblique bearings on the bolt and hammer, so as to withdraw the point of the striker within the face of the bolt. This oblique cam action also gives great power to the extractor at first starting the empty cartridge case out of the chamber.

The magazine, M, is simply a sheet iron or steel box of a size to hold five cartridges, but there seems no reason why it should not be of larger dimensions. It is detachable from the rifle, and is inserted from underneath into a slot or mortise in the stock and in the shoe, in front of the trigger guard. A magazine catch, C, just above the trigger guard, engages in a notch, N, in the rear of the magazine, the projection, L, first entering a recess prepared for it in the shoe. There is a magazine spring, D, at the bottom of the magazine box which pushes the cartridges up into the shoe. The point of the top cartridge is pushed into the projection, L, and this keeps the lower cartridges in their places in the box while the latter is detached; when the magazine is inserted in the rifle, the withdrawal of the bolt causes the top cartridge to be slightly drawn back, so that it is now free to be fed up into the shoe by the magazine spring, D.

There is a later pattern of magazine, which has its front face quite plain, with no projection, L, as the magazine catch was found sufficient to hold the box in its place. To prevent the cartridges being pressed out of the magazine before the latter is inserted in the rifle, there is a strong spring placed vertically in one side of this box, the curved upper end of which bears upon the top cartridge; when the magazine is in its place in the shoe, this side spring is so acted upon that it ceases to hold down the cartridges in the box.

To use the rifle as a single loader, formerly the magazine had to be detached, when a spring plate in the shoe, which is pushed aside by the insertion of the magazine, starts back into its place and nearly fills the magazine slot, so as to prevent cartridges falling through to the ground when fed into the chamber by hand. The later pattern, however, has two notches on the magazine for the catch, C, to engage in. When the magazine is inserted in the slot only as far as the upper notch, the rifle can be used only as a single loader, but on pressing the box home to the second notch, the magazine immediately comes into play.

The magazine can be released from the slot by an upward pressure on the lower projecting end of the magazine catch, C, which is covered by the trigger guard.

Improved Lee.—This rifle is precisely similar in principle to the Lee, the chief difference being that the magazine is permanently fixed in its slot underneath the shoe, and in front of the trigger guard. The cartridges are inserted from above. There is a stop by means of which the cartridges can be prevented rising up into the shoe, and which forms a sort of false bottom to the slot in the latter, so that the arm can be used as a single loader.

Lee-Burton.—The bolt action is the same as the Lee, but the box magazine is attached to the right side of the shoe, instead of being underneath, as in that rifle. When the magazine is raised to its higher position, the cartridges pass successively into the shoe by the action of gravity alone, and are thus pressed home into the chamber by the closing of the bolt.



A number of the Lee-Burton and improved Lee rifles are now being manufactured for issue to the troops, in order to undergo experimental trials on an extended scale.

Several other magazine rifles have the box central magazine, but placed in different positions as regards the shoe and the axis of the bore. In the original pattern of the Jarman (Sweden and Norway), the magazine is affixed to the upper part of the shoe, inclined at a considerable angle to the right hand (see vertical cross section, Fig. 11). Here the operation of gravity obviates the necessity of a magazine spring, but the magazine was found to be very much in the way and liable to be injured. It has therefore been replaced by a magazine underneath the barrel, as in the Kropatschek and other rifles.—Engineering.

(To be continued.)

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PRESERVATIVE LIQUID.

For a few weeks' preservation of organic objects in their original form, dimensions, and color, Prof. Grawitz recommends a mixture composed of 21/2 ounces of chloride of sodium, 23/4 drachms of saltpeter, and 1 pint of water, to which is to be added 3 per cent. of boric acid.—Annales des Travaux Publics.

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KENT'S TORSION BALANCE.

The United States Torsion Balance Company, of New York, has recently brought before the public a new form of balance which presents so many ingenious and excellent features that we illustrate it below, on the present page. The instrument in its simplest form is shown in Fig. 1. It consists of a beam, A, which is firmly attached to a wire or band, B, at right angles to it, and which wire is tightly stretched by any convenient means. Then, since the wire and beam are both horizontal in their normal position, and since the center of gravity of the beam is immediately above or below the middle line of the wire, the torsional resistance of the latter tends to keep the beam horizontal and to limit its sensitiveness. When the beam is deflected out of its horizontal position and the wire thereby twisted, the resistance to twisting increases with the arc of rotation. To counteract this resistance and to render the beam sensitive to a very slight excess of load at either end, a poise, D, is attached to the beam by a standard, C, which poise carries the center of gravity of the structure above the axis of rotation. This high center of gravity tends to make the beam "top heavy," or in unstable equilibrium. By properly proportioning the poise and its distance above the wire to the resistance of the wire, the top-heaviness may be made to exactly neutralize the torsional resistance, and when this is done the beam is infinitely sensitive.



The moment of the weight or its tendency to fall increases directly as the sine of the arc of rotation, while the torsional resistance increases as the arc, and for small angles the sine and the arc are practically equal.

When arranged as in Fig. 1, the scale is balanced only when the center of gravity of the structure is vertically above the middle line of the wire, and the support of the scale must be leveled in the direction of the beam, so as to cause the center of gravity to take this normal position. After the scale is thus leveled, if from any cause whatever, such as shifting the scale on a table, or shifting the table itself, the scale support is thrown out of level, the center of gravity of the poise and beam is shifted from the vertical line above the support, and its moment immediately becomes greater than the torsional resistance, and the beam tips out of balance, and cannot be used as a correct scale until the support is again leveled.



In spite of all the foregoing facts, it was reserved for the "Encyclopedia Britannica," in its ninth edition, to use the following as the result of its condensed wisdom:

"In the torsion balance proper, the wire is stretched out horizontally, and supports a beam so fixed that the wire passes through the center of gravity. Hence the elasticity of the wire plays the same part as the weight of the beam does in the common balance. An instrument of this sort was invented by Ritchie, for the measurement of very small weights, and for this purpose it may offer certain advantages; but clearly if it were ever to be used for measuring larger weights, the beam would have to be supported by knife edges and bearing, and in regard to such applications therefore (as in serious gravimetric work), it has no raison d'etre."



This would seem to settle the whole case, for if the encyclopedia says it has no reason to be, then, like the edict of the Mikado, it is as good as dead, and if that is the case, "Why not say so?" On the contrary, the torsion balance seems very much alive. But as it is not very generally known, perhaps the early history of this form of balance, briefly sketched, may prove of interest.

One of the first forms of the torsion balance which met the disapproval of the "Encyclopedia Britannica" was attended with the difficulty that the pivoted wires were attached directly to the bifurcated ends of the beam, and could not be tensioned without bending these ends unless the beam was made so heavy as to interfere with its employment in delicate weighing.



The next step was the substitution of light forms stiffened by the wires being tensioned over them. This was the invention of Professor Roeder, recently deceased. The next step was the common counter scale, and then that form of letter scale in which one of the bands acts as a fulcrum and the other as a pivot.

After Professor Roeder's death, Dr. Alfred Springer, of Cincinnati, continued perfecting this invention, and with marked success—scales not intended for anything but the weighing of the ordinary articles of a grocery store working so accurately that up to 50 lb. two grains would turn the balance.

As will be noted, this balance dispenses entirely with knife edges, and this statement carries with it the gist of its entire merit. There is no friction, and the elegance of the work and the nice adjustments of the parts struck the writer at once.



The prescription scale and the proportional scale (see Fig. 4) are particularly interesting. The former is sensitive to 1/64 of a grain, and the latter, invented by Mr. Kent, is a most ingenious method for weighing, by which, in a small compass (101/2 in. by 41/4 in. by 33/4 in.), we have a balance capable of weighing 3 lb. avoirdupois by thirty-seconds of an ounce.

For ordinary balances on the torsion system, in which extreme sensitiveness is not needed, the trouble caused by change of level of the scale is insignificant; but it becomes a matter of importance in more sensitive scales, such as fine analytical balances in places where it is impossible to keep the table or support of the scale level, for instance on shipboard.

To counteract this effect of the change of level, Dr. Alfred Springer devised the system which is shown in its most elementary form in Fig. 2. An additional beam, E, with wire, F, and poise, H, on support, C, were added to the balance, and connected to it by a jointed connecting piece, J. The moment of the structure, E C H, about its center of rotation was made equal to the moment of A C D about the center. The wires, B and F, are attached at their ends to supports which are both rigidly connected to the same base or foundation. If this base, the normal position of which is horizontal, is tipped slightly, the weights, C and H, will both tend to fall in the same direction. But suppose the right hand end of the base is raised, causing both of the weights to tip to the left of the vertical, D, tending to fall over, the left tends to raise the right hand end of the beam, and the connecting piece, J H, also tending to fall to the left, tends to lower the left hand end of E and the piece, J. The moments of the structure, E C H, and A B D being equal, and one tending to raise J and the other to lower it, the effect will be zero, and J will remain in its normal position.

It is not at all necessary, however, to have the weights and dimensions of the structure, E C H, equal to those of A B D. All that is necessary is that the components of the weight of each part of the structure which act vertically on J shall be equal and opposite. For, if the left end of the beam, E, is made shorter than the right end of the beam, A, a given angle of rotation of the beam, A, will cause a greater-angle of rotation of E, consequently will tip the weight, H, further from the vertical than the weight, D, is tipped, and in that case the weight, D, must be made smaller than H, to produce an equal and opposite effect upon J. In practice it is convenient to make the beam, E, only one-fifth to one-twentieth as long as A, and to correspondingly reduce the weight, H, relatively to D. In this case, on account of the angle of rotation of the beam, E, being greater than the angle of rotation of A, the beam, E, becomes a multiplier of the indications of the primary beam, A.

Mr. Kent has devised a modification of Dr. Springer's system, which is shown in Fig. 3. It is applied in those varieties of the torsion balance in which there are two parallel beams, connected by either four or six wires. The wire, F, carrying the secondary beam, E, and poise, H, instead of being carried on an independent support, rigidly attached to the base, as above described, is attached directly to a moving part of the balance itself, and preferably to the two beams. In Fig. 3, T T T are trusses over which are tightly stretched the wires, B B B. A A' are two beams rigidly clamped to the wires; t is another truss with stretched wire, F F. The upper wire, F', is attached by means of a flexible spring and standard, S, to the upper beam, and the lower wire is attached either directly or through a standard to the lower beam. The secondary poise, H, is rigidly attached to the truss, t. The secondary beam, E, is also rigidly attached to the truss, and acts as a multiplying beam. The secondary structure thus completely fills two functions: First, that of multiplying the angle of rotation and thereby increasing the apparent sensitiveness of the scale, and, second, that of overcoming the effect of change of level. The secondary beam may be dispensed with if a multiplier is not needed, and the secondary truss, t, with its standard and counterpoise, H, used alone to counteract the effect of change of level. Fig. 5 shows a modification of this extremely ingenious arrangement.—Engineering.

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LINK BELTING.

[Footnote: From a paper read before the "Technischen Verein" of New York, May 28, 1887.]

By CHAS. A. SCHIEREN.

The old saying that "there is nothing new under the sun" may well be applied to leather link belting. It is generally believed that these belts are of recent invention, but that is an error. They are over thirty years old.

Mr. C.M. Roullier, of Paris, experimented that long ago with small leather links one and one-half inches long by three-quarters of an inch wide. These links had two small holes at equal distances apart, and were joined with iron bolts, which were riveted at the ends, thus making a perfectly flat surface, and in that way forming a belt entirely of leather links.

Mr. Roullier's idea was to economize; he therefore utilized the material left over from the manufacture of flat belting. He perfected his belt and came to this country in 1862, when he patented the article here and tried to introduce it. At first it produced quite a sensation, and many tests were made, but it was soon found that Roullier's belts were not suited to running our swift motion machinery, and they were therefore abandoned as impracticable.

Mr. Roullier then introduced his invention into England, where he met with some success, as his belt was better suited to English slow motion machinery.

These belts are now largely used in England, many good improvements have been made in them, and almost every belt maker in Great Britain manufactures them.

Mr. Jabez Oldfield, of Glasgow, has the reputation of making the best and most reliable link belt in Great Britain. He has also the reputation of being the originator of these belts. This is, however, an error, the credit of the invention belonging, as we have said, to Mr. Roullier.

Mr. Oldfield, nevertheless, has invented many useful machines for cutting and assorting the links. He has also introduced improved methods for putting the links together.

For more than twenty years after Mr. Roullier's visit, nothing was done with leather link belting in this country.

In 1882, however, Mr. N.W. Hall, of Newark, N.J., patented a link belt, composed of leather and steel links. His method was to place a steel link after every third or fourth leather one, in order to strengthen the belt. In practical use this belt was found to be very defective, because the leather links soon stretched, and thus all the work had to be done by the steel links. The whole strain coming thus upon the steel links, they in course of time cut through the bolts and thus broke the belt to pieces. So this invention proved worthless.

In 1884 a Chicago belt company obtained a patent on another style of link belt. In this belt all the little holes in the links were lined with metal, similar to the holes in laced shoes. This produced an effect similar to that produced by Hall's patent. The metal lining of the holes cut the bolts into pieces by friction and thus ruined the belt. Therefore this patent proved a failure also.

After all these failures it fell to our lot to improve these belts so that they may now be worked successfully on our American fast running machinery. During the past two years we have made and sold over five hundred leather link belts, which are all in actual use and doing excellent service, as is proved by many testimonials which we have received.

Our success with these belts has been so surprising that we think we have found, at last, the long looked for "missing link," not in "Darwinism," however, but in the belting line. We prophesy a great future for these belts in this country.

How have we attained such success? First: We found that Roullier made a mistake in using leather offal, as, in the links of an iron chain, if one link is weak or defective, the whole chain is worthless, so in link belts, if one or two links are weak or made of poor material, the whole belt is affected by them. It is therefore of vital importance that only the best and most solid leather be used in making the links; second, the leather must be made very pliable, but at the same time its toughness and tenacity must not be injured, or it will stretch and break.



These things are of great importance, and are the principal reasons for the failures of all former efforts. The leather which Roullier used was stiff, hard, and husky. He believed that the harder the link the greater its tensile strength, but upon actual test this was found to be a fatal error.

Our leather links are saturated with a mixture of tallow, neatsfoot oil, etc. This makes them very pliable and increases their toughness, so that they will stand a strain three times as great as a piece of hard rolled sole leather.

In manufacturing this belt, the joining together is important. The links must be accurately assorted as to thickness, and the outer links countersunk, to admit the bolt. Then the most valuable improvement of all is our "American joint" (see Fig. 1).

By close inspection you will observe that it is absolutely necessary to use half length bolts for the width of wide leather link belts.

Examine Figs. 2 and 3. In the latter you will notice one length of bolt placed on a round faced pulley. That belt must either bend or break, and in any case it will not give satisfaction; but, on the other hand, examine Fig. 2; here two half length bolts are used, and ingeniously joined in the center. It gives just pliability enough to lay the belt flat upon the pulley. We experimented for some time before perfecting this important improvement.

We also took out four patents for different methods of joining, but abandoned them all and adopted the "American joint" system (Fig. 1) as the most efficient, simple, and reliable. It gives the belt an unbroken flat surface and is far superior to anything so far introduced for that purpose.

We have not stopped at flat link belting, but have turned our attention to manufacturing round solid leather link belting, and believe that we have almost attained perfection in that line. As the illustrations clearly show, there is quite a demand for inch and upward solid round belting, and the difficulty always has been to join such a belt together. All steel hooks, etc., do not seem to satisfy. This, our new invention, is so simple that it hardly needs explanation. A belt of this kind can be taken apart in a short time, and shortened or lengthened at pleasure.

Now, Mr. President and gentlemen, I shall be glad to answer any questions in reference to these link belts, or give any further explanation you may desire.

Question.—Can these link belts be used on dynamos for electric lights?

Answer.—Yes. In England they are used almost exclusively on dynamos. However, they run only 700 revolutions per minute there, whereas our slowest dynamo runs 1,100.



Quest.—Would you advise link belts for high rate of speed?

Ans.—No; they give better results on slow running machinery.

Quest.—Have these belts any special advantage over flat leather belting?

Ans.—Yes, decidedly. When belts are run half crossed, or what is termed quarter turn, it is very hard to make flat belts lie perfectly even on the pulleys. These link belts, however, cover the entire face of the pulley (see illustration), and therefore are superior for that purpose.



Quest.—Why do they give better results when run slow?

Ans.—Partly because of their great weight over ordinary belting, also their grip power is stronger when run slow. No belt is superior to them for slow, hard working machinery.

Quest.—Are they more expensive than ordinary flat belting?

Ans.—Not when compared to the work they can accomplish.



Quest.—Can they be run in wet places, such as mines, etc.?

Ans.—Yes; by waterproofing the leather, no cement being used as in flat belts. The links can be made positively waterproof. We have furnished paper mills, tanneries and bleacheries, and other exposed places with waterproof link belts, and all have been entirely satisfactory so far.

Quest.—Can they be run on ordinary flat pulleys?

Ans.—Yes; our "American joint" link belt can be run on any straight or rounded pulley, whether made of iron, paper, or wood, and being all endless they run much smoother than other belting.



Quest.—How are they made endless?

Ans.—By a very simple process (see illustration), and takes almost less time than lacing a flat belt. All that is necessary is to take both ends and interlock the links, then pass the bolt through and rivet it, and when you wish to shorten the belt proceed likewise: File off the end of the bolt and take out, or add rows of links at pleasure and rejoin it again.



Quest.—What is the relative strength of a link belt compared to flat belting?

Ans.—Nothing definite has yet been ascertained. We are preparing a table showing results, and so far we can report that they can stand about twice the strain of double flat belts. A four inch link belt one inch thick is able to do the work of an eight inch flat double belt.



Quest.—Explain the advantage of your American joint over the English hinge.

Ans.—The American joint gives a perfect unbroken surface of entire width of belt, whereas the English hinge joint makes two half widths, and whenever a sudden change of power occurs and the belt runs half way off the pulley, it will catch at the edge and tear everything to pieces.



Quest.—Have you a table or schedule of their weight per square foot?

Ans.—Yes. The following is as near as we can estimate the weight of leather link belting per square foot:

1 inch thick, about 5 lb. per sq. ft. 7/8 " " " 41/2 " " " 3/4 " " " 4 " " " 5/8 " " " 31/2 " " "

Upon motion a vote of thanks was passed, and the paper read ordered to be printed.



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A NEW PROCESS OF CASTING IRON AND OTHER METALS UPON LACE, EMBROIDERIES, FERN LEAVES, AND OTHER COMBUSTIBLE MATERIALS.

[Footnote: Abstract of a paper read before the Franklin Institute, April, 1887.—J.F.I.]

By A.E. OUTERBRIDGE, JR.

The art of making charcoal—if, indeed, so crude a process is worthy of being dignified by the name of an art—dates back to a remote antiquity, and has been practiced with but little change for hundreds of years. It is true that some improvements have been recently made, but these relate to the recovery of certain volatile by-products which were formerly lost.

Every one is familiar with the appearance and characteristics of ordinary charcoal, yet I hope to show you this evening that we still have something new to learn about its qualities and the unexpected practical uses to which it may be applied.

We commonly regard charcoal as a brittle, readily combustible substance, but we have before us specimens in which these qualities are conspicuously absent. Here is a piece of carbonized cotton sheeting, which may be rolled or folded over without breaking, and, as you see, when placed in the flame of a Bunsen burner, the fibers may be heated white hot in the air, and when removed from the flame, the material shows no tendency to consume. Here, again, we have a piece of very fine lace, which has been similarly carbonized, and displays the same qualities of ductility and incombustibility.

These carbonized fabrics may be subjected to much more severe tests with impunity; and when I tell you that they have been exposed to a bath of molten iron without injury, you will readily admit that they possess some qualities not ordinarily associated with charcoal. When removed from the mould in which they were placed after the iron casting had cooled, not a single fiber was consumed, but upon the face of the casting there was found a sharp and accurate reproduction of the design, thus forming a die. This die may be used for a variety of purposes, such as embossing leather, stamping paper, sheet metal, etc., or for producing ornamental surfaces upon such castings.

Some of the carbonized fabrics displayed upon the table are almost as delicate as cobwebs, and one would naturally suppose that when a great body of molten metal is poured into a mould in which they are placed, they would be torn to fragments and float to the surface even though they were unconsumed, yet such is not the case. I have found in practice that the most delicate fabrics may be subjected to this treatment without danger of destruction, and that no special care is needed either in preparing the mould or in pouring the metal.

By the aid of the megascope, the enlarged images of some of these castings, showing the delicate tracery of the patterns, will now be projected upon the screen, and you can all see how perfectly the design is reproduced.

In these experiments, the mould was made in "green sand" in the ordinary manner, and the fabric laid smoothly upon one face, being cut slightly larger than the mould, in order that it might project over the edge, so that when the moulding flask was closed, the fabric was held in its proper position. As the molten metal flowed into the mould, it forced the fabric firmly against the sand wall, and when the casting was removed, the carbonized fabric was stripped off from its face without injury. In this way several castings have been made from one carbonized material.

These castings are as sharp as electrotypes, whether made of soft fluid iron or of hard, quick-setting metal. This peculiarity is owing to the affinity between molten iron or steel and carbon. The molten metal tends to absorb the carbon as it flows over it, thus causing the fabric to hug the metal closely. It is somewhat analogous to the effect of pouring mercury over zinc. You know that when mercury is poured upon a board, it runs in a globular form, it does not "wet" the board, so to speak; but when poured upon a plate of clean zinc, it flows like water and wets every portion of the zinc, or, as we say, it amalgamates with the zinc. So when molten iron is poured into an ordinary sand mould, which has been faced with this refractorily carbonized fabric, it wets every portion of it, tending to absorb the carbon, and doubtless would do so if it remained fluid long enough, but as the metal cools almost immediately, there is no appreciable destruction of the fibers.

The casting which I shall now exhibit represents a very interesting and novel experiment. In this case, the piece of lace, having open meshes a little larger than a pin's head, instead of being laid upon one face of the mould, was suspended in it in such a way as to divide it into two equal parts. Two gates or runners were provided, leading from the "sinking head" to the bottom of the mould, one on each side of the lace partition. The molten iron was poured into the sinking head, and flowing equally through both runners, filled the mould to a common level. The lace, which was held in position by having its edges embedded in the walls of the mould, remained intact. When the casting was cold, it was thrown upon the floor of the foundry and separated into two parts, while the lace fell out uninjured, and the pattern was found to be reproduced upon each face of the casting.

The question naturally arises, Why did not the iron run through the holes and join together? The answer may be found in the fact that the thin film of oxide of iron, or "skin," as it is popularly called, which always forms on the surface of molten iron, was caught in these fine meshes, and thus prevented the molten metal from joining through the holes. I have repeated the experiment a number of times, and find that the meshes must be quite small (not over one fiftieth of an inch), otherwise the metal will reunite.

I think that this observation explains the cause of many obscure flaws found in castings, sometimes causing them to break when subjected to quite moderate strains. We frequently find little "cold shot," or metallic globules, embedded in cast iron or steel, impairing the strength of the metal, and it has long been asked, "What is the cause of this defect?" The pellicles have been carefully analyzed, under the supposition that they might be alloys of iron and nickel, or some other refractory metal, but the analysis has failed to substantiate this theory. Is it not probable that in the process of casting, little drops of molten metal are sometimes splashed out of the stream, which immediately solidify and become coated with a skin of oxide, then falling back into the stream of rapidly cooling metal, they do not remelt, neither do they weld or amalgamate with the mass, owing to this protective coating, thus forming dangerous flaws in the casting?

The process of carbonizing the delicate fabrics, leaves, grasses, etc., is as follows: The objects are placed in a cast iron box, the bottom of which is covered with a layer of powdered charcoal or other form of carbon, then another layer of carbon dust is sprinkled over them, and the box is covered with a close fitting lid. The box is next heated gradually in an oven, to drive off moisture, and the temperature slowly raised until the escape of blue smoke from under the lid ceases. The heat is then increased until the box becomes white hot. It is kept in this glowing condition for at least two hours. It is then removed from the fire, allowed to cool, and the contents are tested in a gas flame. If they have been thoroughly carbonized, they will not glow when removed from the flame, and the fibers may even be heated white hot before consuming.

Of course, the method employed to carbonize the materials is suspectible of variation, but the scientific principles involved are unchangeable, viz.:

(1) Partial exclusion of air and substitution therefor of a carbon atmosphere.

(2) Slow heating to drive off moisture and volatile elements.

(3) Intense and prolonged heating of the partly charred objects to eliminate remaining foreign elements, and to change the carbon from the combustible form of ordinary charcoal to a highly refractory condition.



NOTE.—Fig. 1 is photographed from a white iron casting made upon carbonized coarse lace; the lower portion of the plate shows the lace embedded in the iron. Fig. 2 is a casting in gray iron upon lace laid on an iron plate. Fig. 3 is a casting in hard iron upon lace laid on dand. Fig. 4 is a casting in gray iron upon a piece of thin summer dress goods with machine embroidery.

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RECENT PROGRESS IN GAS ENGINEERING.

At the recent meeting of Scottish gas managers Mr. A. Macpherson, of Kirkcaldy, the chairman, said:

THE REGENERATIVE SYSTEM OF RETORT FIRINGS.

For me to attempt, with the time at my disposal, to do full justice to many important points which have cropped up since our last meeting, and which will, no doubt, have been engaging your individual attention, would be impossible. But I think there can be no doubt that, although at our last meeting we had a very full and interesting discussion on the different systems of regenerative retort settings, still we might very profitably spend a little time to-day in hearing the experience of those who have had some of the systems introduced into their works since then, or who may have gained further experience with the system they were then working, or have introduced improvements or modifications thereon.

For the purpose of inducing a discussion on this subject, I will give you the result of the working of the bench of retorts which I erected three years ago on the Siemens system. As I stated last year, my experience up to that time had not been altogether a happy one, but one of sunshine and cloud alternately. I am glad to be able to say, however, that since then I have had nothing but the utmost satisfaction in the working of the regenerative settings. The chief difficulties I have before experienced were of a mixed nature—choked ascension pipes, entailing considerable loss of gas; the choking of the orifices from which the secondary heated air issued to join the producer gas; and the eating away, in a "scooped-out" sort of fashion, of the brick lining of the producers at the points where the primary air entered. These, I am pleased to be able to say, I am now completely clear of; and this has had the effect of converting what was before a considerable source of annoyance and anxiety into as perfect a working bench of retorts as any one could desire.

The results I have obtained have caused me much surprise, being far in excess of anything I ever anticipated; and the saving effected will materially assist in compensating for the greatly reduced value of residuals. I may state that I have used 30 per cent. of fuel on an average, saved from 25 to 30 per cent. on stokers' wages, and increased my production of gas per ton of coal; while the regularity of the heats was a pleasure to look upon.

As showing what I have been able to accomplish, I will give you a few details. I was able regularly to produce 10,000 cubic feet of gas per mouthpiece in 24 hours—the size of my retorts being 18 by 13 inches by 9 feet long, inside measure; and on a sudden dullness coming on, with an increase of first class cannel I produced from 33 retorts 357,000 cubic feet, or at the rate of 11,500 feet per mouthpiece in 24 hours. With 32 retorts I made as much gas as would have required 42 retorts to produce on the old system. But I know that even this can be excelled; and I am aware that there are works where, by the introduction of retorts measuring 21 by 15 inches, instead of 18 by 13 inches—and which, I may say, can be put quite easily into the same arch—a production of 12,000 cubic feet per mouthpiece can be obtained. This will, of course, still further reduce the cost of production.

With such an experience, gentlemen, I think it is almost needless for me to add that I am a strong advocate of the regenerative system. I have often heard it asked, "But can the system be profitably adapted to small works?" In answer to this, I will say I have proved that it can. During last summer the manager of a small gas works in my neighborhood called on me regarding the working of this system, and expressed a desire, if it was at all possible to adapt it to his present settings without much expense, to try it. I must say I admired his progressive spirit and pluck; and, after a somewhat lengthy conversation with him, during which I gathered the full details of his working and his requirements, I determined to encourage him in his desire to prove if it could be successfully applied to a works of the size mentioned. The present setting consisted of three [semicircle] retorts in one arch; and one of his stipulations to me was: "You must so contrive the setting that if it should prove a failure I can reconvert it into the old system in a few hours." I at once saw that the stipulation was reasonable, or he might be caught in a fix in midwinter. But, with true "Scotch caution" and forethought, he was, while anxious to experiment, determined not to be "caught napping." After some consideration, I prepared a sketch for him of how I thought it could be done, and at the same time comply with his stipulation; and having received full explanations, he set about it, and has had it working now for something like six months. His experience has been somewhat similar to that of most of those who have gone in for the new system. It did not answer very well at first. But after a little manipulation and experience in the proper working and management, it is now acting in first rate style, and is saving fuel, with better and more regular heats; and this although it is not constructed in such a way as to yield the best possible results, owing to the before mentioned stipulation having to be considered and allowed for in construction.

In answer to an inquiry I made the other day, the gentleman referred to informed me that he has now had this setting in operation for six months. He has three retorts, 14 by 16 inches, and 8 feet long, in an oven carbonizing 2 cwt. of coal every four hours; the heats are higher and more regular; and the retorts easier kept clear of carbon. The coke drawn from the top retort is sufficient for fuel. My oven would hold four retorts; and the same fuel would heat this number just as well as the three. I used only the coke from Cowdenheath parrot coal for this setting; but had to mix it with Burghlee coke for the old system of setting.

No doubt most of you will have noticed the satisfactory results obtained by Mr. Hack, of the Saltley Gas Works, Birmingham, and by Mr. McMinn, of Kensal Green, with the furnaces employed by them for gaseous firing without recuperation, whereby they are enabled to save fuel and carbonize more coal per mouthpiece than with the old system. Still they admit that the saving by this setting is only in fuel, with increased production, but without any economy of labor—one of the points in favor of regenerative setting being a saving of at least 25 per cent. in the latter respect. Even where regenerative settings cannot be had, I think the system of using gaseous fuel is well worthy the attention of managers; the expense of altering the existing settings to this method being very small.

IMPROVEMENTS IN GAS PURIFICATION.

I must now, however, pass on to some other topics. After the proper production of the gas, we have still the processes of purification to consider, and how this operation can best be effected at the smallest cost, combined with efficiency and the least possible annoyance to residents in the immediate vicinity of gas works. I think all gas engineers are agreed that in ammoniacal liquor we have a useful and powerful purifying agent, although each one may have his own particular idea of how this can be most efficiently applied—some advocating scrubbers, others washers. But these are things which each one must determine for himself. But in whatever way it is applied, we know that it can be profitably used for this purpose; and I am not without hope that it may soon be found possible to remove nearly all the impurities by this means.

At present, however, this is not so. And consequently we have a variety of other methods employed for the complete removal of the impurities. But, by whatever means it is effected, it is unquestionably the duty of the gas engineer to send out to the public an article from which the whole of the impurities have been removed.

In Scotland, no doubt, our chief purifying material is lime, although I know that several of our friends have for some time been using oxide of iron, and perhaps they will favor us with their experience and a statement of the relative cost of lime and oxide. I am not aware that either the Hawkins method or the Cooper coal liming process has yet received a trial from any Scotch gas engineer.

BURNERS AND REGENERATIVE LAMPS.

But even after we have been able to produce and send out gas of the greatest purity, our troubles are frequently only beginning, as, very often, consumers do not use, but simply waste and destroy the gas by bad burners and fittings. Nothing, however, will convince them that they are in any way to blame for the light being poor. I am certainly of opinion that gas companies would do the public a service in supplying them with suitable burners for the quality of gas that is being sent out for consumption. I have myself for some years adopted this policy, and almost invariably find that complaints cease and consumers are pleased with the results.

We have now also so large a number of really good regenerative lamps which give excellent results, and can be made in a great variety of very neat and ornamental designs, that we ought to endeavor to the utmost of our power to introduce them to the public, and, if possible, induce them to use them not only in halls and similar places, but in their dwelling houses, as with these lamps a most thorough and efficient system of ventilation can be carried out, by which the heat that is so much complained of in gas-lighted apartments is reduced to a minimum, and the atmosphere of such apartments is rendered healthy and agreeable.

With such improved lamps at our command, I think we have nothing to fear from the competition of the electric light, which during the past year has not made any very startling advance—generally attributed by electricians to the restrictive legislation under which they have been placed. Let us hope this is now about to be removed. I am sure we all rejoice that such is the case, as all we want is a "fair field and no favor." We can with confidence await the result.

THE WELSBACH GAS LIGHT.

In the mean time, however, while electricity for lighting purposes has, to say the least, not made any startling advances, we have, besides the regenerative lamps before mentioned, the new Welsbach light, which is exhibited before you to-day, by the kindness of Dr. Wallace; and if the results said to be obtained by it are at all what they are represented to be, we certainly have a new departure in gas lighting of no mean order. Dr. Wallace—a gentleman who is well known to us as one well qualified to test its merits—has found that the Welsbach burner produces a light equal to more than 9 candles per cubic foot of gas of 25 candle power, thus nearly doubling the amount of light compared with gas consumed in the ordinary way.

The construction and manufacture of the burner I have seen described in these terms: Chemists have been diligently working for many years on the problem of how to convert into light the highly condensed heat of the Bunsen burner; and a Vienna chemist now claims to have solved it.

The first condition of the problem was to find a medium on which the heat could be perfectly concentrated and raised to illuminating power. Many experiments have been made with platinum in a Bunsen flame, and a brilliant enough light has been produced, but at a cost altogether outside commercial use. The Vienna chemist, Dr. Welsbach, has discovered a composition which is as good a non-conductor—that is to say concentrator—of heat as platinum, is much more durable, and a great deal cheaper. The base of it is a peculiar clay, found in Ceylon, which combines the indestructibility of asbestos with the non-conducting property of platinum; and having found the incandescent medium, he has next adapted it to the Bunsen burner.

In this arrangement there is the simplicity of genius. He gets a fine cotton fabric woven into the shape of a cylinder, with a tapering point. In its first stage it is about 2 inches in diameter; and after being coated with the composition, it is subjected to a strong heat. This has two effects—first, the cotton fiber is completely burned out, while the composition retains the shape of the woven surface on which it was moulded. Then the cylinder contracts and solidifies until it becomes about the size of the forefinger of a glove. Dr. Welsbach calls this his "mantle;" and by a simple arrangement he fits it on a Bunsen burner, and places an ordinary lamp chimney over it. When the flame is applied, the "mantle" becomes incandescent, and gives out a brilliant yellow light, which, it may be said without exaggeration, will compare favorably with any electric light yet put on the market.

For decorative effect a pretty frosted globe is used; and by varying the globe a pure white or a pure yellow may be obtained. It is also added that there is no act of Parliament required for it, nor even a provisional order of the Board of Trade. No streets have to be broken up in order to lay down pipes; and no wires have to be hung across the roofs of protesting householders.

The whole apparatus can be got ready to fit on an ordinary gas bracket; and two or three spare frames with "mantles" can be kept in the house in case of accident. Whoever sees the Welsbach incandescent light in operation will readily admit that it is the "coming light." It has beauty, brilliancy, purity, and economy all on its side.

Let us hope (added the chairman) this description is not overdrawn; but of this you will later on have an opportunity of judging for yourselves. No doubt the general or even partial adoption of this light would have a tendency to reduce the consumption of gas, as a smaller quantity would be required to produce the same amount of illumination. Nevertheless, gas engineers will hail it with approval if it in any way tends to popularize the use of gas, and helps to increase the comfort and improve the sanitation of our houses, churches, halls, etc. Moreover, gas is continually being adopted for fresh purposes; and we can confidently look forward to an almost unlimited field in the rapid and ever increasing use of gas as a fuel and for cooking purposes, as well as for motive power. The new and really excellent gas engines now being brought into the market will, no doubt, create a healthy rivalry, and tend to cheapen these useful machines, and so bring them within the reach of many persons who have hitherto been prevented from employing them by their considerable first cost.

PARAFFIN AS A RIVAL OF COAL GAS.

But while the day has gone by when any one of us fears the electric light as a possible rival, we are not insensible to the fact that paraffin oil, from its present low-price, is a rival which we cannot afford to despise. And more especially is this the case in many of the smaller towns and villages, where the charge for gas is of necessity higher than in the larger towns.

Doubtless, with oil there is not the same cleanliness as with gas; while there is also more trouble, attention, and considerable danger attending its use. Still, in these "hard times," most people are inclined to adopt the cheapest article, even at the cost of these drawbacks, so as to make their money go as far as possible.

But not only as an illuminant is it being brought into direct competition with gas, but also as a fuel and for cooking purposes, as well as for motive power. And I am inclined to think that the sooner we set about trying to solve the problem of how to meet this new competitor, the better.

OIL IN GAS MAKING.

A new departure has also recently taken place in the adoption of oil for gas making purposes. This, of course, is more fraught with danger to the coal master than to gas companies, inasmuch as, should this prove to be a more economical raw material from which to produce illuminating gas than coal, our present coal gas works could be easily remodeled and turned into oil gas works. This process has recently been introduced into a village in Fifeshire. And I have made it a point to visit and inspect the works, which have been converted into an oil gas works, so that I might be able to lay a few particulars before you. The process, however, has not been in operation long enough to enable me to give you much information on the subject, especially in the way of details of cost, working expenses, or permanency of the gas under varying and low temperatures. The patentees claim that they can produce 100 cubic feet of 60 candle gas from a gallon of oil, or at a cost of 3s. 11d. per 1,000 cubic feet for oil, fuel, and labor; no more expense being incurred, as the gas does not require purification.

At Colinsburgh (the village alluded to), I was informed that the man sent by the patentees could produce 100 cubic feet of gas per gallon of oil; but they had no means of testing the illuminating power. The gas company's own servant, however, only produced 80 cubic feet per gallon, which they attributed to his want of experience in knowing the proper heat at which to work the retorts. Whether or not this was so I cannot tell; but of this I am certain, that the statement made that the gas does not require purification will not bear investigation. When I tested it for sulphureted hydrogen and for ammonia, both were indicated in such an unmistakable manner as none of us would care to see in our coal gas as sent out to the consumer.

PRICES OF RESIDUAL PRODUCTS.

What is of far more real consequence to us than the possible change from coal gas to oil gas, however, as long as we remain manufacturers of the former, is the value of our residual products, which has suffered so great and sudden a decline in value, for which various remedies have been proposed, though none of them, I regret to say, have as yet restored anything like the former value. A statement of the highest prices realized for coal tar products, and a comparison with those obtained on the 30th of March last year and at the same time this year, may not be uninteresting:

Highest Price on Price on Price March 30, March 30, 1886 1887 - -+ per gal. per gal. per gal. + - - -+ L s. d. L s. d. L s. d. + - - Crude naphtha 0 4 0 0 0 41/2 0 0 81/2 Benzol (90 per cent.) 0 15 0 0 1 4 0 2 6 Solvent naphtha 0 2 6 0 1 0 0 1 2 Burning naphtha 0 1 7 0 0 101/2 0 0 10 Creosote oil 0 0 3 0 0 03/4 0 0 1 per ton. per ton. per ton. - -+ L s. d. L s. d. L s. d. + - - Pitch 1 14 0 0 15 0 0 12 6 Sulphate of ammonia 21 5 0 13 10 0 11 10 0

This shows a great fall in value from highest to lowest, which seems to have been touched last year, except in the case of pitch and sulphate of ammonia, both of which have marked a considerable decline, even since last year, but it is pleasing to note that the others have shown at least some slight improvement—crude naphtha and benzol having during the year risen nearly one hundred per cent. in value. Let us hope that this is the precursor of a general rise in value from which we shall all profit. For the purpose of bringing about this much desired end, I understand that some of the gentlemen present to-day have been burning their tar in the retort furnaces, and as it will be interesting to know what success they have attained, I hope some of them will favor us with their experience on this subject.

In conclusion, let me express the hope that the time is not far distant when the general trade of the country will attain to its wonted prosperity, by which every branch of industry will benefit—ours among the number; and that the hard times we have experienced, now for a considerable number of years, may not again return.

Discussion next took place regarding the Welsbach incandescence gas light, which was opened by Mr. McGrilchrist, who remarked on the very fragile and tender nature of the "mantle," and expressed a hope that in this direction improvement might be looked for. It was certainly a beautiful light, and as to its consumption, he stated that the lamp then shown to the meeting was only burning two cubic feet of gas per hour. [A voice: Two and two-tenths.] He felt satisfied that it would enable the manufacturers of gas to compete with paraffin oil, so that with Glasgow gas they could have such a light as they saw at the rate of 4d. for about fifty hours.

Mr. W. Key (Tradeston Gas Works) made a statement giving the results of inquiries he had made at St. Enoch Station Hotel, where the light has for some time been on exhibition. From the answers given to his inquiries he spoke rather disparagingly of the lamp, but chiefly on account of the expense involved in renewing the "mantles" and the glass chimneys. He admitted, however, that the lamps which he had seen were placed very unfavorably, being exposed to the action of somewhat violent draughts, and he subsequently remarked that the lamp was of such a nature as to effect the complete combustion of the carbon contained in the gas. The burner must, therefore, be regarded as a great boon—as the burner, in short.

Mr. D.M. Nelson (Glasgow) gave his experience gained in connection with the light, remarking that one of the great drawbacks to it was the very great rarity of the mineral from which the zirconium was obtained. So scarce was it that it would become dearer than platinum and more valuable than gold if the lamp came into general use. The light which the lamp gave out, though it possessed intensity, was deficient in diffusibility as compared with that given out from ordinary flat flame gas burners, and this was another objection to it. He argued at some length against the financial aspects of the scheme which was being promoted to buy up the Welsbach patents, and to introduce the lamp into this country. His advice to his friends was not to have anything to do with the Welsbach company, and, as investors, to be very careful in accepting all the statements made about the light, which he predicted would not be a financial success.

Mr. McCrae was strongly opposed to any discussion being raised in regard to the question being considered in its financial aspects. They, as gas engineers, did not require to trouble themselves with the doings of investors. He regarded the Welsbach burner as an improved appliance for consuming gas. It was an invention which was quite new to him, and as he was not in possession of any facts which would enable him to condemn it, he thought they ought, at least, to give it a fair trial. Referring to the fragile nature of the "mantle," he remarked that there were minds at work aiming at giving a purer and more brilliant light from gas, and so far he was of opinion that the light before them was a success. His opinion as to the diffusibility of the light emitted from the burner differed from that of Mr. Nelson, as he considered the light possessed that quality in a high degree. He had no doubt that the minds already at work on the incandescent light would seek out means for improving the burner.

* * * * *

To varnish chromos, take equal quantities of linseed oil and oil of turpentine; thicken by exposure to the sun and air until it becomes resinous and half evaporated; then add a portion of melted beeswax. Varnishing pictures should always be performed in fair weather, and out of any current of cold or damp air.

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THE NEW BRITISH COINAGE AND JUBILEE MEDAL.

An important addition will be made to the coins now in circulation by the issue of the double florin, the design of which is shown in one of our engravings. The reverse is composed of crowned shields, bearing the arms of the United Kingdom arranged in the form of a cross between scepters, a device which was first adopted for coins of Charles II. It was designed by Thomas Simon, the greatest of all English engravers, and it remains to be seen whether this handsome coin will be generally popular. The reverse of the florin will for the future bear the same design.

During the past year her majesty was pleased to signify her pleasure that a portrait medallion, by Mr. J.E. Boehm, R.A., modeled from life, should be substituted for the effigy which the coins have hitherto borne. In the new effigy, her majesty appears crowned and veiled, with the ribbon and star of the garter and the Victoria and Albert order. The legend "Victoria Dei Gratia Britanniarum Regina, Fidei Defensor" is variously arranged on the different coins, according to the exigencies of the design.

The opportunity has at the same time been taken, with her majesty's approval, for making certain alterations in the designs for the reverses of some of the coins by abandoning those which did not appear to possess sufficient artistic merit to warrant their retention. The reverse of the sovereign will still bear the design of St. George and the Dragon, by Pistrucci, first adopted for the sovereigns of George IV., and the reverses of the half-sovereign and threepence remain unchanged, except that the crown has been assimilated to that used for the new effigy. The St. George and the Dragon design will be resumed for the five-pound piece, the double sovereign, and the crown, this design having been adopted for these pieces when originally struck. The half-crown will bear the same reverse as that coin bore when first issued, a design of considerable merit, by Merlin. During the last half century public taste appears to have been satisfied, both in this country and abroad, with some such insignificant design as a wreath surrounding words or figures indicating the value of the coin; and the shilling and sixpence have, during the present reign, been examples of this treatment. They will in future, like the half-crown, bear the royal arms, crowned, and surrounded by the garter.

The queen was further pleased to command that the fiftieth anniversary of her majesty's accession should be commemorated by the issue of a medal. The effigy for this medal, which is also from a medallion by Mr. Boehm, has a somewhat more ornate veil than that on the coin; and on the bust, in addition to the Victoria and Albert order, is shown the badge of the imperial order of the crown of India. The reverse is a beautiful work by Sir Frederic Leighton, President of the Royal Academy, of which the following is a description: "In the center a figure representing the British empire sits enthroned, resting one hand on the sword of justice, and holding in the other the symbol of victorious rule. A lion is seen on each side of the throne. At the feet of the seated figure lies Mercury, the God of Commerce, the mainstay of our imperial strength, holding up in one hand a cup heaped with gold. Opposite to him sits the Genius of Electricity and Steam. Below, again, five shields, banded together, bear the names of the five parts of the globe, Europe, Asia, Africa, America, and Australasia, over which the empire extends. On each side of the figure of Empire stand the personified elements of its greatness—on the right (of the spectator), Industry and Agriculture; on the left, Science, Letters, and Art. Above, the occasion of the celebration commemorated is expressed by two winged figures representing the year 1887 (the advancing figure) and the year 1837 (with averted head), holding each a wreath. Where these wreaths interlock, the letters V.R.I. appear, and, over all, the words 'In Commemoration.'"

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