MECHANICS AND USEFUL AETS. 59 



is regularly sliunted into another series, along which it comes out when 

 the gun is fired, and the grooves for exit being shallower than those for 

 entrance, they, as it were, squeeze the shot with sullk-ient force to make 

 it take the form of rifling, and give it the rotation on its axis. It was 

 loaded with a hollow-headed conical-shaped shot, 19^ inches in length, 

 weighing 230 Ibs., with a 45-lb. charge of powder behind it. It sent 

 the shot with a velocity of 1,405 feet per second full on the thick part 

 of the target, inflicting a broad damaging indent, shaking the whole 

 structure a good deal, and cracking an outer upper plate; but still 

 there was no through penetration. 



The next shot was by Thomas's 7-inch muzzle-loader. This gun 

 was 11 feet 6 inches long, rifled on a new plan, somewhat in ap- 

 pearance like the canon raye of the French, but with this difference, 

 that instead of three grooves it has three ridges projecting nearly an 

 inch into the bore ; the elongated projectiles, 2-1 diameters long, fitting 

 into and between the ridges. The shot fired was a wrought-iron one 

 of 151 Ibs. weight, with a charge of 25 Ibs. of powder." It was the 

 first time the gun had ever been fired, and it hit the white spot aimed 

 at so truly as quite to obliterate the mark, doubling up the shot itself 

 into the form of a huge cauliflower, and making an indent almost as 

 severe as that of the 100-pounder smooth-bore. Its velocity was 1,21-5 

 feet per second when it struck. The target appeared much shaken, 

 but was still impenetrated. 



Mr. Whitworth's gun was then again fired, at the same range and 

 with the same charge oT powder and shot. The shot was aimed at 

 the untouched plates, below the embrasure, and so close to the ground 

 that the projectile struck the earth first, making a deep furrow"; and, 

 of course, considerably diminishing the force of its blow. For this 

 reason it made but a very slight impression, and did no injury to the 

 target that was worth speaking of. 



The 10-inch Armstrong gun was again fired, with a charge of 45 

 Ibs. of powder, and a wrought-iron shot of 230 Ibs. This tremendous 

 missile injured the target considerably, and sent fragments of it flying 

 through the air in all directions, with a hoarse roar that was terrible to 

 hear. The force of this blow broke some of the plates in fresh places, 

 knocked the head off one of the bolts, and drove out another like a 

 rocket. 



Thomas's gun was again fired, with 27-1 Ibs. of powder, and a steel 

 bolt weighing 133 Ibs. Its maker stated he was afraid of his gun, as it 

 was too deeply bored ; and it was, therefore, fired with electricity, from 

 a battery some distance off. When the charge was ignited, the gun 

 burst into fragments ! The explosion was so complete that the masses 

 were scattered in every direction, one piece weighing nearly a ton 

 being thrown to a distance of 140 yards. The experiments were then 

 terminated for the clay. This gun had a steel interior tube, and an 

 iron breech banded with a shrunk hoop 13 inches in width and 3 

 inches thick. The total diameter where it burst at the breech was 29 

 inches. It was claimed that the victory remained with the target. 



On the 1 7th of March following, the experimentation commenced 

 on the third was continued. The target used on this occasion was 12 

 feet square, formed of three great plates of the best rolled iron ; the 

 upper one being 5-1 inches thick, the middle one 1\ inches, and the 



