MECHANICS AXD USEFUL ARTS. 51 



the entire breech-end, weighing about seventeen hundred pounds, 

 being blown off and carried one hundred and fifty feet behind. 



In these experiments there was no denying that the gun had the 

 best of it. The target was so fearfully mutilated, that if it had been 

 a ship afloat, seeing the effect of only four shots, she would have been 

 in as bad a predicament as a timber ship* The injury to the armor- 

 plates and to the skin and frame, great as it was, was not so dis- 

 astrous as the destruction of the fastenings. Three-fourths of the 

 bolts which held the plates were gone. Of thirteen bolts, with which 

 the centre-plate was secured, eleven were visibly broken. This dam- 

 age to the fastenings arises from the plate, when struck, being bulged 

 and driven into the wood backing, which affords no support, but 

 yields to the blow ; consequently, the butts buckle and start with a 

 tremendous rebound from their bearings, tearing away the bolts. 

 The three plates were dished, driven in at the centre, and curled up 

 at the ends, one nine inches, and the other six or seven inches off 

 from the wood backing. 



It was further remarked, as a singular exception to the effects of 

 former target experiments, that the armor-plates were not cracked 

 at the bolt-holes. The explanation seems to be that the velocity 

 and force of the projectile being so great as to penetrate the plates 

 through and through, owing to the non-resistance of the wood back- 

 ing, the shot did its work without causing the same amount of vibra- 

 tion as a shot at a lower velocity, on the same principle as a rifle-bail 

 will pass through a pane of glass without cracking it. In former ex- 

 periments, heavy shot at low velocities, and shell which produced 

 only slight indentations in the iron, caused extensive cracks at the 

 bolt-holes. 



But notwithstanding the destruction of the target in these experi- 

 ments, the result was claimed to be in favor of the system of defence, 

 rather than that of the attack, and for two reasons: First, because 

 the range was only two hundred yards, leaving an inference that - at ten 

 tunes that distance the shot would have failed to make any serious im- 

 pression ; and, second, because the destruction of the target was only 

 effected by an effort which also destroyed the gun, a risk not to be 

 thought of taking on shipboard. 



The triumph of the defence was, however, of short duration ; for 

 the rupture of the Armstrong gun left the way open to other compet- 

 itors, and a long-neglected piece, that had lain remote from view for 

 several years, was suggested as deserving of an opportunity to try its 

 powers. This was the so-called " Horsfall " gun a wrought-iron 

 smooth-bore piece of ordnance of thirteen-inch calibre, capable of 

 carrying a ball of two hundred and eighty-six pounds, weighing 

 twenty-two tons, and forged at the Mersey Steel and Iron Works, 

 Liverpool. A target, representing part of the side of the armor-clad 

 frigate Warrior, was used. It consisted of four-and-a-half-inch iron 

 plates backed with eighteen inches of solid teak wood. The gun was 

 loaded with a solid spherical shot, and a charge of seventy-five pounds 

 of powder, and it was placed at the usual distance of two hundred 

 yards from the target. The first shot was conclusive. It smashed 

 through the entire target, and completely destroyed it for further ex- 

 periments. 



