[Illustration: Carriage and Slide for 21-cm. Gun.] [Illustration: Slide Tackle-Block.] [Illustration: Hinged Carriage Tackle-Block.] [Illustration: Buffer.] The slide consists of two heavy double T-iron rails bent in front. They are connected by three bottom plates, and an angle-iron joining the front ends. Seven compressor-bars are laid in the centre of the slide, and from the middle to the rear bottom plate a wooden platform is laid. Two railway buffers are provided at either end for taking up the shock in violent running in or out. The fighting pivot-flap is a stout bar hinged to the front end of the slide so as to have vertical motion; a single eye in the end enters the jaws of the pivot-shackle in the centre of the port. The slide rests on front and rear rollers, the front ones being permanently in action and the rear ones, on eccentric axles, being thrown into action by levers. The 24-cm.-gun slide is provided with a windlass for running in and out and training. This consists on each side of the slide of a pinion turned by crank and gearing in a spur-wheel which carries the bollard. The out and in tackles are carried directly to the windlass. For training, the fall of the tackle is rove through a leading-block hooked just forward of the windlass to give a fair lead. Housing pivot-flaps are hinged at each end of the slide, which drop and key over bolts projecting from the deck. Bow and stern pivot-slides are provided with transporting rollers, which ship just inside the traversing rollers and work on eccentric axles. There are three traversing circles on the deck: the front and rear are for the front and rear rollers, the centre one holds the slide when it buckles from the position of the gun on it. [Illustration: Centre Pivot-Bolt.] [Illustration: Centre-port Pivot-Bolt.] [Illustration: Eccentric Axle and Handspike Socket.] [Illustration: Windlass for Training and In Tackles.] [Illustration: Front Housing-Bolt.] _Carriage and Slide for the Long 21-cm. Gun, Pattern 1869._ This pattern only differs from the former in being heavier braced. The fighting pivot-flap is not hinged, but is three-armed and secures to the slide by shackle-bolts. Shifting slides are provided with a third pair of rollers just forward of the centre of the slide, which are thrown in action when pivoting around the rear pivot-bolt; from their position, they lift the forward rollers clear of the deck when in action. _Cabin-Carriage for the Long 21-cm. Gun._ [Illustration: Training-Gear for Cabin-Carriage.]