The Works Of Messrs. Schneider And Co.

SCHNEIDER-CANET NAVAL TURRETS. LO —* intervals with cleats or brackets that carjy the cartridges. By working the chain, ammunition is delivered from the magazine on a lower deck to the gun, as it is required. The chain is operated by the piunger piston of a double- acting hydraulic cylinder. To this end, the head of the piunger piston is provided with two jointed levers, bedring alternately on the spindles of the rising and descending sides of the chain, so that the latter always turns in the same direction round the pulleys wliichever way the piston acts. A spring cleat at the bottoin of the hydraulic cylin- der engages the chain automatically, and holds it fast when the motion of the piunger piston changes its direction. The loading table can l>e turned round, and is fitted with concentric compartiments, in which the cartridges are placed as they are removed from the magazines ; it rests on rollers that bear on a cast-iron baseplate. Each com- partment of the loading table is brought automatically opposite the hoist, and the gunner has only to slide the cartridge on its bottom to place it on the hoist. The auto- matic working of the loading platform is insured by gear- ing driven by the lower pulley of the endless chain, the varions parts being so arrangée! that the hoisting of a charge corresponds with the shif'ting of the loading plat- form from one compartment to the next. On reaching the top, one end of the cartridge engages in a guide, and is prevented from falling when it leaves tlie hoist tube. The cartridges are placed by hånd into the gun. The opening for discharging the empty cartridge-cases is cut in the rear of the turret in its vertical wall ; it is closed by a cover and a double bolt. The elevation of the gun, which ranges from — 10 deg. to +15 deg., is obtained by causing the carriage to oscil- late in the mounting by means of a double-acting hydraulic cylinder, the piunger rod of which is jointed to the under- side of the carriage. This hydraulic cylinder is fitted to the mounting frame, its distribution valve being worked by the gunner from the turret. The gun is trained by means of two hydraulic cylinders, placed under tbe armoured deck, eacli working a plate-cliain, one end of which is fixed to the body of tlie hydraulic cylinder, and the other end passing over a drum fixed to the turret socket. The lateral training mechanism is arranged so as to work the turret when the ship has a list of 5 deg., and to hold it fast under an angle of 15 deg. The delivery and exhaust of water under pressure take place through a valve at the bottom of the cylinders ; this valve is loaded at K) kilogrammes (142 Ib. per square inch), in order to keep the chain taut and to fix the turret should the pipes leak or burst. The distribution gear of the lateral training cylinders is placed on the orlop deck, in the cylinder space ; but it is worked from the firing platform by means of a geared transmission, placed in the turret : while in the pit, on a level with tlie distributør, are a wheel and an endless screw, working a gun-metal disc to fix the system ; this disc is made with two concentric grooves connected by an incline, and in which a roller travels fitted to the distribution valve-rod. The difference between the radius of the concentric parts of the grooves corresponds with the travel of the distribution valve. When the turret is not in service, the roller is in the middle of the incline, and by turning the disc one way or the other, the valve becomes displaced and causes one cylinder to be supplied with water under pressure, and the other ready for exhaust. The turret is thus caused to turn, drawing the disc round with it ; when the latter has resumed its former position, the valve closes and tlie turret stops. By this arrangement the turret is always under the gunner’s control ; the valve ports are calculated so as to insure the required précision in the training of the gun. Six men are required for operating the turret and serving the gun. Schneider-Canet Turrets for 305-Millimetre (12-In.) Guns (Fig. 799, Plate CXXXVII., and Figs. 800 and 801).— The principal parts of these turrets are the mounting, training, and elevation mechanisnis, loading apparatus, distributørs, and safety devices, provided for the varions operations. The gun is held on the carriage by means of damps, rings, and pins. The centre of gravity of the gun being in front of the bearing base, the carriage rests in front on a trunnion block, while in tlie rear it throws a vertical strain on the damps. The sides of the mounting serve as slides for the carriage; they arejoined in front by a stay, and in the rear by the cylinder for working tbe gun. This is in one piece with the mounting, the double-acting piston- rod being fixed to the lower rear end of the carriage. During recoil, the liquid driven from the rear passes to the front through loaded valves and pipes. In order to cause the recoil cylinders to take up the largest possible portion of the recoil, tbe valves are only loaded to about 32 kilo- grammes (455 Ib. per square inch), a sufficient pressure to keep tlie gun run out at all angles. When water under a pressure of 80 kilogrammes (1138 Ib. per square incli) is introduced in the rear of the cylinder for running out the gun, the valves are exposed to an extra hydraulic pressure, which keeps them closed until the instant that firing takes place. As soon as recoil commences, this surcharge is removed. The recoil cylinders are cast on the sides of the carriage ; during recoil, the liquid passes from the rear to the front through vents in the pistons. The pistons are provided with counter-rods in front. The revolving platform, built of steel plates, carries the mounting and the gun, as well as tlie protective armour ; it is bolted to the top part of the socket. The latter transmits the whole weight of the movable turret to the ship’s framings; on the top is a gun-metal ring which slides inside the circular guide, and ends at its lower part with the hydraulic pivot. This can travel vertically over 40 millimétrés (1.575 in.) in a step bearing, the travel being regulated by an automatic valve mounted on the pivot, the rod of which is joined to the step bearing in such a way that the admission of water under pressure beneath the pivot, is closed by the turret itself when it reaches the firing position, and opened if the turret has a tendency to get lowered. Special latch-bolts on the platform lock the turret when it is not in service ; these 3 H