The carriage is a single-plate one, having two brackets, two transoms, and a bottom plate assembled by angle-irons. The bottom plate is slotted for the Elswick compressor.[5] This compressor is a modification of the American 15-inch one. It is made up of six bars of plate-iron, all of which are movable and which are placed lengthwise in the slide like the wooden balks in the American type. Seven plates hang through the slot in the bottom plate of the carriage, being loosely secured to it. The plates and bars are pressed together by rocking levers worked by screw-shafts, the shafts being worked by levers. The screws on the shafts are of different pitch. That on the right is called the compressing, having a quick pitch; when it is moved it presses the plates against the other lever, which, having a finer-pitched screw, is called the adjusting. The lower end of the adjusting lever is prolonged to form a trip-stop so that the recoil of the gun will throw the lever down automatically. [5] See cut, page 201. [Illustration: 7-inch Slide.] The front rollers of the carriage are permanently in action, whilst the rear ones are on eccentrics. The elevating-gear is the wheel and ratchet. The slide has a slope to the front of 3°. The slide-rollers are on eccentric axles. Attached to the rear of the slide is a simple system of winch-gear for running in and training. This is nothing more than a spur-wheel and windlass revolved by a pinion and crank. In using it, the fall of the in-tackle or training-tackle is caught over the windlass which is turned by the crank. In revolving slides, or slides which shift from one port to another, there is a separate attachment under the forward end, which is nothing more than a centre roller which when thrown into action raises the forward rollers clear of the deck; the after-end of the slide being held by a pivot-bolt, the forward one is swung to a new pivot-centre. This centre roller is thrown into action by gearing. Two ordinary bollard-heads are attached to the rear of the slide, so that the carriage may be held back or veered out in a seaway by turns of the in-tackle falls about them. _Carriage and Slide for 8-inch M. L. R._ [Illustration: 8-inch Slide.]