The Works Of Messrs. Schneider And Co.

HYDRAULIC BALANCED TURRETS. 243 the platform caused a tendency to revolve, owing to the eccentricity of the movable mass. Tliis .effect varied, of course, with the extent to which the sbip rolied. The result was a considérable difficulty in producing lateral displacements for training the gun, or even a temporary immobility of the system. As the deck of a ship at sea is in a state of constant oscillation, the varions inechanisms gave more or less trouble, producing uncertainty in the firing manœuvres. Hydraulic brakes were then little known and seldom resorted to. and the mountings which were placed in the turrets were much longer than those now used, thus leading to the adoption of protective armour of large diameter and considérable weight. The conséquences of the earlier mode of construction and requiring a trained and cool-headed personnel ; indeed, under the beat conditions the power of the guns could only be utilised to a limited extent. At the same time, turrets did not play the important part in the armament of ships which they do now, owing to the great improvements that have been introduced. Schneider-Canet Barbette-Turret for 27-Centimetre (10.630-In.) Gun (Figs. 803 to 807, Plate CXXXVIII.).— This type of turret has been supplied to the Greek Admiralty for the armament of the eruisers “ Psara,” “ Hydra,” and “ Spetzaï.” Each turret was delivered complété, with gun, mounting and frame, revolving and training mechanism, hoist, &c. The trunnions of the gun rest in the trunnion-plates Fig. 802. Closed Turret and Mounting for 27-Centimetre Gun. working such turrets may be briefly stated as follow : Firing was comparatively slow, as after each round tlie turret had to be turned for a new supply of ammunition. Effects due to the eccentricity of the system either pro- duced sudden movements, or, offering considérable résis- tance, deranged the operations of training the gun or even stopped them at times ; in extreme cases, the transmissions became totally disorganised. The working gear had con- sequently to be strengthened owing to these varions strains, and the power of the engines had to be increased above that acually required, in order to counteract the tendency to revolve, due to the oscillations of the platform. The armour had also to be made of dimensions and weights excessive in proportion to the offensive power of the gun it protected. It is easy to see, therefore, that under such conditions the working of the varions parts was difficult, cast with the carriage ; this consists mainly of the two recoil cylinders, with slides and clamps. Inside are two compensating cylinders, joined to the recoil cylinders by pipes. The mounting consists of two checks, the top surfaces of which form the slide paths. Rollers facilitate the travel of the carriage. On the front cross-stay are butts corresponding with the buffers on the carriage. The recoil piston-rods are iixed to the rear end of the slides ; those of the compensating cylinders are attached to the front stay of the carriage. When the gun is fired, the liquid, which is compressée! in the front of the recoil cylinders, flows to tlie rear, whence it is driven into the compensating cylinders the dimensions of which are carefully calculated. When the recoil is complété, the intermediate valves fall back 011 their seats, and the mounting remains run in, until com-