416 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



A^ A~ represent the guns The trunnions ff, are mounted in bearings G, 

 in the inside of the turret 3/, and the spherical form of the guns allows 

 each to be rotated to any extent desired, without uncovering the port. 

 Each gun moves inward to a small extent, before rotating it, the bearings 

 G being adapted to allow such motion, and to induce it, by the gravity of 

 the gun, so soon as the parts which prevent such motion are removed. 



FF^, are substantial cheeks, or movable braces, standing so that one is 

 partly embraced and sustained by the other, and /is a stout wedge, adapted 

 to operate between these cheeks, and, by their aid, to brace the guns out- 

 ward very rigidly. I force outward both guns, so that they apply them- 

 selves firmly to the interior of the turret, before firing either. When the 

 gun, represented on the right hand side of the figure, is fired, its tendency 

 to recoil is resisted, first, by its own inertia; second, by the inertia of the 

 cheeks FF^, and wedge I; third, by the inertia of the gun, on the left hand 

 side of the figure; fourth, by the inertia of the entire turret 31; and, 

 finally, by the elasticity of masses of rubber K and K^, which are intro- 

 duced in the manner represented. 



On the scale represented, the guns are fourteen inches caliber, and weigh 

 each fifty-one tons; and on any scale which may be assumed, each gun 

 weighs about one hundred times as much as the charge which is fired 

 therefrom. The recoil of such guns, thus braced and provided, will not b€ 

 so great as to occasion serious inccmvenience. L, L, represent rollers 

 which support the turret M, and its attachments, and allow it to turn freely. 

 J/', represents the circular track, or stout ring, on which the rollers L, L, 

 traverse. N, N, are holding-down bolts, which pass through the rubber 

 K, and are adapted to allow much lateral movement. P, is a hollow cylin- 

 der of iron, provided at the bottom with large doorways F^, to allow the 

 ingress and exit of the men, and with gearing Q, and a capstan B, by 

 which it is rotated. This cylinder is connected with the turret M, through 

 the aid of strong pins or projections V, which stand in suitable jaws v, on 

 the inside of the turret at its base, and compel the turret to turn therewith, 

 while at the same time, allowing for sliglit imperfections in the adjustment 

 of the parts, by the liberty of the projections V, to move vertically in the 

 jaws V. W, is an endless screw, adapted to be rotated by the winch w, 

 near the bottom of the structure. It stands near the rear face of one of 

 the spherical guns yl2, and a like screw, not represented, stands near the 

 opposite gun. X, X, are two nuts which are carried on the same screw 

 W, and which are moved simultaneously, up or down, according as W is 

 turned in one direction or the other. Y, F^, are wire ropes which are 

 wound each partially around the gun, fitting tightly in a groove in a piece 

 Z, bolted on the gun for the purpose. The rope Y, is attached to the nut 

 X, and the rope F\ to the nut X^, and both ropes are firml}' secured to the 

 gun. These ropes and nuts incline the gun in either direction, and to any 

 extent which maybe desired, by simply turning the screw W in the proper 

 direction by the crank w. 



I provide strong heavy beams 31'^, 3r^, across the base of the turret 3f, in 

 the directions represented. These sustain the weight of the bracing parts, 

 and resist that portion of the recoil which is directed downward, when tho 

 guns are fired at high elevations. 



