The Works Of Messrs. Schneider And Co.

CLOSED-IN TURRET FOR 12-CENTIMETRE GUNS. bO the elevating arc tixed to the gun. An index titted to the horizontal shaft of this mechanism travels over a scale, and marks the angular position of the gun with relation to the platform. The lateral training mechanism can be worked electrically or by hånd ; the required motion is obtained by the rotation of a pinion moving with the turret, and which engages the circular rack fixed to the ring that forms a path for the two sets of rollers. This pinion is keyed on a vertical shaft that passes through the platform, above the level of which it carries a hélicoïdal wheel ; a series of friction rings is introduced to absorb the momentum of the turret, in case the motor should be stopped too abruptly. The helicoidal wheel is actuated direct by an endless screw fixed to the shaft of the same motor. The latter is completely enclosed in a metal cylinder. It comprises a working shaft, provided at the upper part with a handle, which the man in charge displaces over a graduated scale. The general way in which this apparatus works has been already described. The system is operated by hånd by acting on a wheel, the shaft of which is on the right-hand cheek of the mounting. A toothed wheel is keyed on the hånd wheel, and carries a chain that transmits the motion to a horizontal shaft passing through the slide, and carrying at its end a toothed wheel that can be thrown in and out of gear with the corresponding pinion on the electric motor shaft. The gun is supplied with ammunition by means of a hoist consisting of two endless chains that turn round a double-toothed wheel below, set in motion by the working parts of the mechanism ; at the top they pass over a pulley, the fraines of which are so arranged that the tension of each chain can be regulated. The chains are united by bucket-cup rings movable round horizontal i'ods, and in which the cartridges are placed, the projectile downwards, the point being placed in a smaller cup. When a cartridge is placed in this position, the first cup partly surrounds the head of the projectile, and draws it along. At the top the slide which guides the bottom of the cartridge-ease is rounded, and slightly enlarged before reaching the inclined trough that receives tlie cartridge when the latter turns over round the axis of the corre- sponding bucket-cup. Tlie hoist is worked by hånd, by means of a crank placed inside the central socket, at the end of a horizontal shaft which carries a bevel wheel in the middle of its length ; the rotary motion of the latter is transmitted to the wheel shaft through an intermediate vertical shaft, on which are keyed two other bevel wheels. The sight and scale are carried in jointed supports, which follow the mounting in its displacements. They extend over the roof of the turret, the top of the scale being opposite the sighting opening. The gunner lias, therefore, a wide range for executing all the sighting operations, and he can even follow a movable target. A sliding door closes the turret in the rear. Closed-In Turret for Two 12-Centimetre (4.724-In.) 45-Calibre Quick-Firing Guns (Figs. 826 and 827, Plate CXLIL, and Figs. 828 to 831).—A description of this type is of special inter.est, and the turret we shall here describe is. one forming part of the armament of a battleship. The 12-centimetre (4.724-in.) guns are quick-firing, of the Schneider-Canet system. They are fitted with one- motion breech-blocks, arranged for firing both with electric and percussion fuse. A jacket, with shoulder extensions, surrounds tlie gun, and carries on the sides two slides thai support and guide the gun during recoil by bearing on the top surface of the string-beams. In front of the jacket are the buffers, and underneath is placed the recoil cylinder, in connection with which is a spring récupérât or. The movable cradle consists of a front and rear collar, and of tlie two lateral string-beams which unité them. The gun during recoil slides in the frame thus formed ; the trunnions are in front. Gun-metal bearings, placed inside the collars, insure a perfect guiding of the system. The rear collar is made with a butt, on which is fixed the recoil piston-rod. The recoil cylinders are on the Schneider- Canet system, with central counter-rod. The gun in recoiling draws with it the recoil cylinder, the piston remaining fixed. The liquid passes from one side to the other of the piston, through an annular opening made between the regulating counter-rod and the central groove, and drives before it the movable bottom that carries the rear cross-piece. The Belleville springs are compressée! until the recoil is complété ; they then relax and push back the movable bottom, which drives the glycérine forward, and, as tlie valve is closed, the liquid can only flow slowly through narrow vents of calculated areas. The gun, there- fore, runs out again without shock. The movable part of the turret is balancée! on its vertical axis of rotation. The platform consists of a flooring of steel plates strengthened by T-beams, and by a ring made of angle-bars ; it carries the pivoting column, which is in the shape of a truncated cone, and the roof. The guns are elevated by hånd ; to this effeet each of the outside string-beams is fitted with a toothed sector which engages pinions keyed on the same shaft with a helicoidal wheel worked by an endless screw. On this shaft is keyed the handwheel operated by the gunner. The lateral training mechanism is worked by electricity or by hånd ; in the former case the motor, which is placed in the front part of the turret, drives, through an endless screw, a helicoidal wheel, that operates an inside gearing with a differential motion. This gearing is keyed on a vertical shaft, at the lower end of which is a pinion that gears with two other pinions placed symmetrically, and engages the toothed circular rack for lateral training. The gunner régulâtes the training at will by acting on the commutator. In the device for lateral training by hånd power, the men Work two cranks placed one on each side of the mountings ; these transmit power through a chain to a shaft fitted with an endless screw, which gears in a helicoidal wheel that surrounds the diflerential gearing above referred to. The helicoidal wheel operates the vertical shaft provided with a pinion which engages the