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 2½ 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.

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.

AN ENGLISH CAR COUPLING.

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.

[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