OF GUN-METAL. I4I

zse be not less than and be for greater security connectedwith the muzzle astragal, by the convex line HLK. Gun-nel not being sufficiently hard to prevent the shot frommaking impression when they strike with great force againstany part of the chase, it would be better, as a means ofobviating this inconvenience in some measure, if the mouldswere placed in a different position from what they are atpresent, with the breech up and the muzzle down, as incasting mortars : by this method the metal at the chafeWould be denser than at the breech, and of course morehard and tenacious. This with proper precautions, may bedone whether the guns be cast solid or with a core.

93. Guns constructed on these principles (92) tho’ suffici-ently strong are defective in two points: they are too light,and consequently their motion being irregular, it is im-possible to fire with justness; and there is a necessity forplacing the trunnions too near the muzzle, that the motioriof the breech may not be so violent as to render abortiveevery attempt to hit the object : from the latter circumstancealso, they cannot enter far enough into the embrazures;which are very soon destroyed by the explosion of the pow-der. The best remedy for these defects is to reinforce thegun particularly at the breech, according to the proportions1‘aid down in the first book of artillery: it will then be suffi-ciently heavy to prevent any irregularity even with the largestcharges; the trunnions may be placed nearer the breech,and the muzzle will enter farther into the embrazures.

94. The dimensions (7, 8, 9,) for the body of the piecebeing thus determined ; the proper position of the trunnions,cashable, base-ring and dolphins must be ascertained. Thetrunnions should be placed between the centre of gravityand the muzzle, that the gun may be rather heavier at thebreech, without rendering it difficult for two gunners to raiseit with their handspikes, for the purpose of laying it, andthat it may enter far enough into the embrazure ; their dia-meter is equal to one calibre. The position of the dol-phins should be such, that when the gun is suspended .bythem, the breech may preponderate a little, that by takinghold of the cashable it may be the more easily managed. It iscustomary to engrave on the upper part of the gun, thearms of the king and the master general of the ordnance,with inscriptions, trophies, &c. which obliges the foundersto raise the base-ring, and the swell of metal at the muzzle

higher