BO REPORT— 18638, 
The weight of shot, solid round, used was 12 lbs. 
Diameter of shot 4°5 inches. (English weight and measure.) 
Diameter of bore for gun-cotton 4:56 inches. 
Diameter of bore for gunpowder 4°67 inches, 
Gun. Cartridges. Initial 
Result. No, | Length of Bore. Material of Charge. | Length. vologity: 
| | 
General Observations. 
in 13% calibres, Powder 3 lbs. 1 oz. 7Din, | 1400 ft. | Normal. 
II. 2 113 A Gun-cotton, 15°6 oz.} 5:1 1375 Cartridges slightly 
EEE | ae " 148 Fr 1407 compressed, filling 
ed Mae Pe eee ” 136 9» 1358 the whole space. 
Vi 1 lly» ” 148 83 1400 Follow cartridges re- 
ya 1 10 ” » 159 ¥ 1426 presented at Plate 
vate | et 5 split: 5 age ek 1402 IL fig, 2, 
The normal performance of ordinary powder-guns gives result I., as com- 
pared with gun-cotton. With gun-cotton, when compressed charges were used, 
each of 13:6 oz., result II., gun 2; the gun was not injured; while with 
14-8 oz. of charge, after a few rounds, a considerable enlargement of the bore, 
where the shot lies, took place. A similar result happened to a second gun, 
No. 3, even with a charge of 13°6 oz., after the first few shots. 
When one of the enlarged cartridges, represented at Pl. II., fig. 2, was 
used, occupying 1:1 of the powder-space, the gun’s endurance was perfect, 
and no loss of effect was sustained, and its practice remained good, as proved 
by results set forth at III. and V., since equal charges in very different spaces 
(i. e, in the ratio of 5 to 8) still produced equal results. 
In proportion as the tube is shorter, an increased charge is required 
(shown by results V., VI., VII.); yet the effect of a normal powder-gun and 
charge may be attained by a tube shortened from 13} to 9 calibres: it follows 
that guns to be used with gun-cotton may be constructed much shorter than 
if intended to be charged with gunpowder*. 
With the largest charge used, 7.¢. 17 ounces, about 1000 shots were 
fired from the same gun, without affecting the piece in the slightest—an en- 
durance very satisfactory, and considerably greater than has been experienced 
with gunpowder. 
This experiment was further continued for arriving at results by empirical 
means as to the strength of metal in various parts of the tube. 
The original tube, formed as depicted at Pl. I. fig. 2, was gradually turned 
off until it assumed the shape figured in broken lines, but without any dis- 
advantageous effect. The metallic strength of 3:7 inches close behind the 
seat of the ball, where, according to experience, the greatest strain takes place, 
and 1:6 at the muzzle, were so moderate that for practical uses no further 
diminution was desirable; hence the experiments in this respect were dis- 
continued. 
Finally, I turned my attention to the object of flattening the trajectory of 
projectiles with this gun, and succeeded to such an extent that a projectile 
fired from the gun horizontally pointed at targets set up at 100 yards from 
each other as far as 1200 yards struck at an even height at 3 feet from the 
eround, and fell without ricochet at about 3200 yards. 
An experiment made with a Krupp cast-steel 6-pounder, demonstrated 
* No details are given as to precision. 
