These cars not only convey the ammunition, but are contrived also to discharge each two Rockets in a volley from a double iron plate trough, which is of the same length as the boxes for the sticks, and travels between them; but which, being moveable, may, when the car is unlimbered, be shifted into its fighting position at any angle from the ground ranges, or point blank up to 45°, without being detached front the carriage. Fig. 2 represents these Rocket Cars in action: the one on the left hand has its trough in the position for ground firing, the trough being merely lifted off the bed of the axle tree on which it travels, and laid on the ground, turning by two iron stays on a centre in the axle tree; the right hand car is elevated to a high angle, the trough being raised and supported by the iron stays behind, and in front by the perch of the carriage, connected to it by a joint, the whole kept steady by bolting the stays, and by tightening a chain from the perch to the axle tree. The limbers are always supposed to be in the rear. The Rockets are fired with a portfire and long stick; and two men will fight the light car, four men the heavy one. The exercise is very simple; the men being told off, Nos. 1, 2, 3, and 4, to the heavy carriage. On the words, “_Prepare for action, and unlimber_,” the same process takes place as in the 6-pounder exercise. On the words, “_Prepare for ground firing_,” Nos. 2 and 3 take hold of the hand irons, provided on purpose, and, with the aid of No. 4, raise the trough from its travelling position, and lower it down to the ground under the carriage; or on the words “_Prepare to elevate_,” raise it to the higher angles, No. 4 bolting the stays, and fixing the chain. No. 1 having in the mean time prepared and lighted his portfire, and given the direction of firing to the trough, Nos. 2, 3, and 4, then run to the limber to fix the ammunition, which No. 2 brings up, two rounds at a time, or one, as ordered, and helping No. 1 to place them in the trough as far back as the stick will admit: this operation is facilitated by No. 1 stepping upon the lower end of either of the stick boxes, on which a cleat is fastened for this purpose; No. 1 then discharges the two Rockets separately, firing that to leeward first, while No. 2 returns for more ammunition: this being the hardest duly, the men will, of course, relieve No. 2 in their turns. In fighting the light frame, two men are sufficient to elevate or depress it, but they will want aid to fix and bring up the ammunition for quick firing. [Illustration: _Plate 4_  Fig. 1  Fig. 2] ROCKET INFANTRY IN LINE OF MARCH, AND IN ACTION.