Chapter 2

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 2½ ounces of chloride of sodium, 2¾ 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 (10½ in. by 4¼ in. by 3¾ 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 F¹. 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.