It is 39½ inches long and weighs 275 pounds. The axis of the trunnions is 14 inches above ground, and the piece can be fired at any angle between 0 and 60 degrees. At the centre of the front transom is bolted the elevating-clamp, which embraces an arc bolted to the under side of the mortar. The lever on the left side of the carriage turns a shaft, which causes the clamp to take hold of the arc when the elevation has been given. A pintle-fork is attached at the front end of the carriage, and a ring on the side of either cheek to which the ends of the restraining rope are fastened. NOMENCLATURE OF 3.6-INCH MORTAR-CARRIAGE.--Carriage-frame; elevating-arc; elevating-arc bolt; elevating-arc guide-pin; double hook; double-hook pin; double-hook bracket; double-hook bracket-pin; cap-square; cap-square keys; cap-square chain eye-pin; pintle-fork; pintle-fork bolt; elevating-arc jaws; shaft for jaws; lever for shaft; bushing for shaft; nut for shaft; screw for bushing; separator; separator-bolt and nut; screws for pointing. PLATFORM FOR 3.6 MORTAR. Yellow pine or oak. Weight complete, 200 lbs. [Illustration: FIG. 53.] This equipment consists of one wooden platform, one cast-iron pintle-block, eight stakes, one anchor-stake, two handspikes, and one pointing-scale. The platform consists of two side-rails, 3-inch, into which are framed and bolted eleven deck-planks, the latter secured to each other by dowels. A 4 × 3-inch piece is bolted to the rear deck-plank by three bolts. Wrought-iron straps, bolted into cross-pieces, embrace the side-rails. The pintle-block is fastened to the front of the platform by four wrought-iron bolts. The pintle-fork on the carriage embraces the pintle, forming the centre of motion of the traversing carriage. The platform is held in position by stakes, two on either side; those in front passing through square wrought-iron rings attached to eye-pieces bolted to the front end of the platform. A brass socket, in which works the brass pivot at the end of the pointing-scale, is placed at a suitable point in the axis of the platform. The anchor-stake, 4 ft. long, is driven in front of the platform. Around the anchor-stake, and held in position by the two pins passing through the stake, is wound the middle portion of the restraining rope, the ends of which fasten to the rings in the cheeks of the carriage. The rope is given five feet slack for recoil. [Illustration: FIG. 54.]