428 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



and a half inches, as otherwise the difference in the temperature between 

 the inner and outer particles induces a serious strain. 



C, D, E and F are heavy washers of steel, prepared with a spring tem- 

 per, and touching each other only at a few points by the aid of the projec- 

 tions, d, e and /, arranged each in a different part of the circle from the 

 next, so as not to coincide in position, but to differ as widely each from the 

 other as possible. This, as will be readily understood from the drawing, 

 allows the elasticity of the washers to be brought into play. 



6^ is a nut fitted upon the steel Ahj a, screw thread, as represented. 

 This is applied against a washer F, with considerable force, so as to com- 

 press or bend, slightly, all the washers between itself and the washer C, 

 resting against the bronze B. 



H is the inner shell, and H~ the outer shell of a bronze casting which is 

 forced, or shrunk on, over the parts before described. This casting is filled 

 •with lead, J, and compressed, and is provided with braces, H^, which connect 

 the inner shell H, with the outer shell E~. A quantity of lead, K, is also 

 introduced between this casting and the spherical chamber, and held by a 

 screw, L. 



It will be seen that this gun possesses compenstion for unequal heating, 

 which forms so conspicuous a feature in some of the guns before described, 

 and, in addition, stores in its capacious cnamber 31, so large a quantity of 

 powder, and allows it to burn so quickly, that the great initial pressure, 

 which is usually felt by the projectile during the early portion of its move- 

 ment, is continued further than usual toward the muzzle, acting a greater 

 length of time against the shot to accelerate its motion, analogous to the 

 motion of mercury in the tube of a common thermometer, due to the expan- 

 sion of the large quantity of mercury contained in the bulb. If a ther- 

 mometer was constructed without the bulb, the expansion of the mercury in 

 the tube, only, would not be sufficiently apparent to give room for gradua- 

 tions, but by the addition of the quantity in the bulb, affected by the'change 

 of temperature, the motion along the tube is very great, and can be pro- 

 portioned to give any required amount of motion in the tube, if the bulb 

 could be made to resist the forces acting upon it. And these are exactly 

 the conditions required in a gun, to attain the highest velocity. I believe 

 my mode of constructing this gun, wnll allow the successful use of this 

 idea, but without my plan of compensation, the structure would be 

 destroyed by the joint effects of the high mechanical pressure and the 

 heat to which it would be subjected. 



Figure 35 represents an implement I have designed, for loading such a 

 gun. i\r is a cylinder of copper, and n, is a hollow wooden stock, by 

 which it may be reached into the gun. n\ is a stop which rests in and 

 against the muzzle, when the loader is fully in place. The cubical con- 

 tents of N, are equal to that of the chamber M, of the gun. 



An elastic disk, or wad 0, is placed upon the convex face of the plunger 

 P, then the powder for a charge is introduced intoiV, next a sheet of paper 

 R, is placed over the end of N, and, lastly, a ring S, is slipped over the 

 edges of the paper, holding it strongly to P. The loader and its con- 

 tents are next introduced into the gun, until the stop n^, rests on the 

 muzzle. The plunger P, is then forced inward by the rod p, passing 



