G4 ANNUAL OF SCIENTIFIC DISCOVERY. 



made of 5 bales of hogs-hair, faced and backed with pine plank 4 inches 

 thick, and fastened with 28 wroughfc-iron bolts. Two of the bales had 

 been subjected to one and the same amount of compression, and two 

 others were compressed alike but differing" in degree from the former, 

 and the remaining bale, as stated by the inventor, was but slightly 

 compressed. The bales were bound with iron hoops. The target was 

 backed with 4 feet of solid clay. 



Dimensions of Target. Eleven feet, three inches long ; four feet 

 wide ; three feet, three and a half inches thick. 



The gun used was a rifled 50-pounder ; charge 3^- Ibs. cannon pow- 

 der; weight of projectile 38 Ibs. The result of the firing was unsatis- 

 factory ; the shot passing entirely through the bales and the clay back- 

 ing, and embedding themselves in a bank of earth 18 feet in the rear 

 of the target. 



Wire-Rope Target. Experiments have been made at the Wash- 

 ington Navy Yard with a target devised by Mr. Hodge, consisting of 

 three thicknesses- of half-inch plate iron, backed by a tissue of wire- 

 ropes fourteen inches thick. The target was mounted on timber nine 

 inches thick, consisting, first, of two one-inch boards (one horizontal 

 and one vertical) and then of two layers of timber three and one-half 

 inches thick, disposed of vertically and horizontally. The dimensions, 

 of the target were as follows: Length, sixty-seven and one-half inches; 

 width, fifty and one-half inches ; iron thickness, fifteen and one-half inch- 

 es ; timber, nine inches. Two shots were fired at this target from a 

 eleven-inch gun, distance eighty-three feet. The first shot, a wrought 

 iron projectile weighing one hundred and fifty-six pounds, with a 

 charge of twenty-five pounds of powder, hit direct and passed clear 

 through the target. Shot No. two, cast-iron, weight one hundred six- 

 ty-five pounds, charge of powder fifteen pounds, hit direct, and, pass- 

 ing clean through the target, buried itself in an earth-bank to a depth 

 of nine feet six inches. 



On the Results of Experiments in Gunner?/ ivitli Iron Target*. 

 In a discussion on this subject, before the British Association, 1863, Mr. 

 Calvin stated that the earlier experiments showed that four and one- 

 half inch plates at least were necessary to resist shot. This thickness 

 of iron still left the plate'liable to be hurt or fractured, and knocked off 

 even when not directly penetrated, and the extent to which it would 

 thus suffer would in some degree be regulated by the backing. The 

 plan adopted in the Warrior was simply that suggested by the idea of 

 bolting a plate of iron to the sides of a wooden ship. The iron skin of 

 the Warrior is covered with two layers of teak planking, each nine 

 inches in thickness, the one horizontal, the other vertical, and outside 

 of those is the armor-plate, four and one-half inches thick, secured by 

 bolts, screwed up with nuts inside of the ship. The wood backing 

 AVIS to prevent the injuries sustained by the plate from being communi- 

 cated immediately to the ship, but it afforded no effectual support to 

 the plate itself. The results of experiments with iron targets having a 

 rigid backing, composed wholly of iron, had demonstrated that this plan 

 was not desirable. The arrangement required for the armor-plating 

 of a ship was a strong front plate, in which deflection under blows 

 should be prevented, but which should have some cushion behind to 

 prevent the full concussion of the blow being communicated to the side 



