The gyn is moved by means of dragropes hooked to the staples of the front, or rear axletrees by Nos. 6 and 7. It can be drawn over hard level ground by the working detachment of six men. On ground of an unfavourable nature, a greater number than this is necessary.
The rear of the gyn is the part where the windlass is fixed.
The detachment being formed a few paces in rear of the gyn, No. 1 gives the word, “Take post for exercise—To the right face—Quick march.” The detachment wheels to the left, and the ranks open out. Nos. 2 and 3 halt one pace in rear of their respective axletree arms. The whole one pace from each other, and covering.
Disposition, and Duties of the Detachment.
| No. 1 commands. | |
| Left side. | Right side. |
| 3 runs the carriage up, or back, heaves round the windlass, assists 7 to sling the gun. | 2 runs the carriage up, or back, heaves round the windlass, assists 6 to sling the gun. |
| 5 runs the carriage up, or back, assists to hold on the fall, stoppers, and unstoppers it. | 4 runs the carriage up, or back, holds on the fall, makes it fast, and lowers the gun. |
| 7 reeves the tackle, slings, and unslings the gun at the chase, and steadies it. xx | 6 reeves the tackle, slings, and unslings the gun near the first reinforce, steadies the gun, and overhauls the tackle. |
Prepare to place the gyn. Place the gyn by hand, (or BY CROSSLIFTING). Reeve the tackle. Prepare to sling the piece. Sling the piece. Haul in the slack. Heave round the windlass. Halt. Stopper the fall. Shift the fall. Halt. The carriage having been run under the piece, or away from it, as may be required, the piece is lowered, and cast loose, each number reversing the operations which he performed in lashing; and raising it.
PART VIII.
GUNNERY.
By the Parabolic Theory, the greatest range is when the angle of elevation is 45°, or half a right angle; and the ranges are equal at angles, equally above, and below 45°. In projectiles, moving with velocities not exceeding 300 or 400 feet per second of time, the Parabolic theory will resolve cases tolerably near the truth; but in cases of great projectile velocities, that theory is quite inadequate, without the aid of data, drawn from good experiments; for so great is the effect of the resistance of the air to projectiles of considerable velocity, that some of those, which in the air range only two or three miles, would, in vacuo, range between twenty and thirty miles. The effects of this resistance are also various, according to the velocity, the diameter, and the weight of the shot.