The rails of the slide are of heavy double =T= iron, connected by =T= and plate iron transoms. The slide rests on a pair of conical rollers, with concentric axles forward and a double pair of rear rollers (concentric) at the rear. The forward pair of the rear rollers and the front rollers travel on smooth tracks, while the rear pair of rollers are pinions working in a rack on deck. The slide is traversed by tackles, except in fine pointing, when levers are shipped on the rear rollers and the fine traversing is done by heaving on them. A pawl working on the rear rollers secures the slide in any desired position. The recoil is checked by friction compressors. There are eight iron compressor-bars on each side of the slide, just inside of the rails, resting on the front and rear transoms. On top of the front transom is a heavy iron dumb-sheave, which receives the bight of a rope breeching. The carriage is of the ordinary form of double plate, mounted on rollers, the forward pair being in permanent action and the rear pair on eccentric axles. Tackles are used for running out and in. The compressor-plates are nine in number on each side, suspended on an axle. The outer plates are heavier than the others. The ones next to the brackets are backed by steel disc-springs. Rocking levers working in screw-threads on the axle press against the inner plates. The levers are worked by a ratchet-lever on the exterior right side, this lever being provided with a trip for throwing it down automatically in firing. Railway buffers are placed at the rear of the slide to act in case of over-recoil. The elevating-gear consists of a flat-linked chain passing underneath and supporting the breech of the gun. The ends of the chain wind about axles in the carriage-brackets, the axles being revolved by endless-screw gearing. Levers for turning this gearing ship outside the brackets. In elevating or depressing, it is necessary to turn the gearing alike on both sides in order to keep the centre link, which is marked, in its place under the breech. In elevating, the gearing must be worked slowly in order to allow the breech to follow down by its preponderance. With the 24-cm. gun, the compressor-plates, 12 in number, are all in the centre instead of being at the sides. [Illustration: Slide-Truck for 19-cm. Gun.] _Slide-Carriage for 19-cm. Gun._