The Works Of Messrs. Schneider And Co.

 BARBETTE TURRET FOR 24-CENTIMETRE GUN. LÇ bearing, and which carries most of the revolving weight ; it serves also to lift the turret for inspecting the rollers. The mechanism for elevating the gun comprises a hand- wheel and two bevel pinions which work a hélicoïdal screw ; the latter drives the gearing, on the axis of which is a pinion that engages a toothed sector fitted to the gun. As the hélicoïdal screw recoils with the gun, it is made to inove on a square shaft parallel with the slides. This mechanism can be worked direct by the gunner who stands in the hood, or by his assistant from the platform. Lateral training is obtained by hand, or by electric power. The required motion is given by the rotation of a pinion which gears in the toothed circular rack fixed to the part forming a roller path. This pinion is keyed on a shaft guidecl by collars fixed on the flooring ; it is joined to a hélicoïdal wheel by an elastic coupling. The hélicoïdal wheel is driven by an endless screw titted to the motor shaft. Lateral training is obtained by acting on the handwheel placed on the left side of the niounting ; this Works, through a cogwheel and a plate chain, the horizontal shaft fitted with a pinion that gears in a wheel keyed on the vertical axle working the rack. A disengaging lever serves to isolate one set of mechanism from the other. Ammunition is raised to the gun in a carrier made with three coinpartments placed side by side, its lower part beino- fitted with a lever provicled with rollers that travel in the guides inside the central tube. The carrier is raised by a chain that turns round a toothed wheel below, and on a tension pulley above. The motor is placed between the two floors of the platform ; it sets in motion a vertical shaft, at the lower end of which is keyed an endless screw working a hélicoïdal wheel ; the latter is joined to the chain-wheel shaft by an elastic coupling. Two commutators serve, one for rai,sing the system, and the other for lowering it. The hoist can be worked by hand, by means of two cranks placed outside the system and keyed on a horizontal shaft ; this also carries the pinion which works the toothed wheel on the cogwheel shaft. The pinion can be shifted to the side of the toothed wheel, thus disengaging the hand-working mechanism. Barbette Turret for 24-Centimetre (9.449-In.) 42.5- Calibre Gun.—Turrets of this type bave been supplied to the Spanish Navy, for the armoured cruisers Princesa de Asturias, Cardenal Cisneros, and Cataluna. The principal characteristics of this type are the following : The whole of the revolving part rests both on a hydraulic pivot and also on a series of horizontal rollers, the latter arrangée! on the top deck ; at the lower part it is guidecl by the pivot, and at the upper part by a series of vertical rollers. The inounting bas an oscillating carriage, with hydraulic recoil cylinders and air recuperators for running oui the gun. The gun and mounting are entirely balancée! on the trunnions, thus allowing rapid elevation by means of an ordinary winch worked by hand-power, or by an electric motor. The gun can be charged at any horizontal angle and up to a certain vertical angle, the ammunition service being direct to the breech. The gun is held in the carriage by tongues and grooves ; the breech end is entirely cylindrical. The platform is circular in shape ; it consists of two longitudinal beams, two transverse stay-girders, and six lateral racliating girders, ail strongly connected and fixed to a flooring made of steel plates. On the top flanges is another flooring, strengthened in front where the gun mounting rests. A circular vertical plate, held in place by angles fixed to the ends of the beams, and by six vertical uprights, carries the turret frame. The cylindrical socket is formed of two plates butt-jointed together ; its top part is placed within a drum built up of plates, which joins it to the platform, the lower part being closed by a cast-steel piece which constitutes a hydraulic pivot on which rests the whole system. The pivot lias a gun-metal lining, and revolves inside a cast-steel hydraulic cylinder. The water required for working the hydraulic pivot is delivered by a small pump, placed near the cylinder and worked by hand or electric power. The fixed roller paths for the horizontal and the vertical rollers are provided in one single cast-steel ring, fixed to the upper deck. The socket is fitted with a drum, placed at a suitable height, round which turn the chains for lateral training. The mountino- consists of the coil around the gun, and of the oscillating carriage. The latter is formed of a trunnion ring in front, and of a rear jacket joined to the ring by means of four cast-steel string beams, the rear jacket being formed by two lateral fofged-steel Blocks, and two cast-steel stay bars ; the Blocks contain the recoil cylinders and recuperators, and each of the cast-steel stay bars has seatings for two rollers, on which the rear end of the gun rests. As has already been mentioned, the gun is fixed to the encircling coil by tongue and groove joints ; the gun rests on the carriage with the interposition of four rollers of forged steel placed in two lateral cheeks forged in one piece with the coil. The gun is thus always supported by the four front rollers of the coil and the eight rollers of the carriage, the efforts for the running in and out of tlie gun being thereby reduced to a minimum. The recoil cylinders are bored in the foroed-steel lateral Blocks ; their centres, and those of the gun and of the carriage trunnions, are in one plane ; this does away with all effect of percussion, and the system has only to withstand, during firing, the efforts of the recoil cylinders, which are in direct opposition to the recoil force of the gun. The piston-rods are fixed, in front, to the encircling coil, and continuée! in the rear as counter-rods of equal diameter, thus forming hydraulic brakes of constant volume. The vents for the flow of the liquid are determined by the ballistic data of the gun, and are caleulated so as to obtain a practically constant résistance in the cylinders. The working of the recoil cylinders is independent of that of the re- cuperators, but in order to simplify the system, and to reduce to a minimum the number of joints, the recuperators have been placed in the same bloeks with the hydraulic