562 TBANSACTIONa OF THE AMERICAN INSTITUTE, 



panded at the moment of the discharge. In all such balls the 

 lead is flush with the surface of the casting, and fits easily within 

 the cylindrical part of the bore when the ball is introduced into 

 the gun. This leaves the grooves entirely open, so that the force 

 of the discharging gas might escape through them^ and thus pro- 

 duce little effect on the ball ; but by the expansion of the lead 

 into the grooves at the moment the powder is ignited the passage 

 of the explosive gases past the ball is effectually prevented, and 

 the ball is compelled to twist with a velocity corresponding to 

 the twist with which the ordnance was rifled. 



An inventor in Alabama, John B, Read, had patented one mode 

 of effecting this, which he (Mr. Stetson,) proceeded to delineate 

 on the black board, and though by no means the first, it was a 

 good specimen of that principle. The lead in this, and all simi- 

 lar projectiles was expanded to the pressure of the explosive gas 

 which was allowed to enter between the balls and the cast iron 

 body [of the shot, and thus to spread it outwards with great 

 force. A serious objection to all cannon balls used on this prin- 

 ciple was the flying of the lead so soon as the ball passed the 

 muzzle. In some experiments by General James, in Rhode Island, 

 last summer, the fragments of the lead belts were reported to 

 have nearly destroyed a board fence situated at a considerable 

 angle from the line of firing. This makes such balls very objec- 

 tionable for ordinary field practice, as they might prove in- many 

 emergencies more destructive to advanced parties or charging 

 columns of their own troops than to the enemy. 



He showed a large sectional drawing of the ball which he con- 

 sidered far preferable to any other yet made public. It was 

 patented by B. B. Hotchkiss, Sharon, Connecticut, and had been 

 extensively and very successfully tested, both by the inventor 

 and the United States ofiicers. He exhibited several diagrams 

 of targets, in one of which 90 per cent of the balls hit the target, 

 7 feet four inches, by 5 feet 8, at a distance of a mile. The U. 

 S. Government had sent 200 of these balls with the howitzer 

 battery presented to the Japanese Government, preferring these 

 above all other patented projectiles. 



The ball is, properly speaking, in three parts — the point or 

 body, and cap or rear piece, and the belt. The two former are 

 of cast iron, the latter of lead- or of lead slightly hardened, or 

 of an alloy but little harder than lead. The cap is driven lightly 

 upon the shot, and cuts slightly into the lead when the shot is 



