The recoil is governed by what is called the Brookwell apparatus. This consists of a drum with a friction-band controlled by a lever at the left side. Turns of a breeching are wrapped around the drum, the ends being fast to it, and the bight shackling to the pivot-bolt in the centre of the port. In running out, cranks ship on the ends of the axle, and the breeching is in this manner wound on the drum by heaving down the brake, the friction-band is tightened on the periphery of the drum, thus easing the recoil. The power of the cranks is not sufficient to enable the gun to be run out by this arrangement, and side tackles have to be used. A reserve breeching is also kept rove, through breeching-holes in the forward part of the brackets. [Illustration: Brookwell Broadside-Carriage.] The ordinary elevating-screw is used, working in a screw-box through the rear transom. _Slide-Carriages._ Slide-carriages are used with all guns of seventeen centimetres and upwards. These carriages are classified as either carriages with fixed or with movable slides; and each of these is subdivided into slides for firing from ports or over the rail. As the necessities have arisen for modifications, changes have been made in the details of these carriages and slides, although the general form has remained the same. As a rule, the pivot centre of the slides is either in the middle of the gun-port or close to the spirketing, always forward of the body of the slide. _Slide and Carriage for Short 24-cm. and 21-cm. Guns, Pattern 1868._ The carriage-brackets are of the double-plate pattern, having a wrought-iron frame, and, connected by a bottom plate, forward and rear transoms secured by angle-irons. The carriage rests on rollers, both front and rear being on eccentric axles. The rear rollers are thrown into action by means of levers, and the act of lifting the rear of the carriage on the axle throws the front rollers into action. The bottoms of the brackets are shod with brass friction-plates for travelling on the slide. The elevating-gear consists of a metal rack and pinion. The front edge of the rack is kept against the pinion by a smooth roller against the rear edge. The pinion is worked by means of a lever and capstan-head outside of the bracket. A screw-brake holds the gear fast, it being worked by a lever. When this lever is thrown up the brake is off, when down it is set fast. The carriage is run out and in by means of tackles, but one tackle being used on each side. The carriage-block for this tackle is a double block working on a hinge midway on the forward end of the bracket. The compressing arrangement is the Elswick pattern (see English Ordnance) of iron bars and plates worked by rocking levers, and having a compressing lever outside of one bracket and a regulating lever outside of the other, the former being provided with a trip for automatic compression. The carriage has also front and rear holding-down clips bolted to the bottom plate.