106 ANNUAL OF SCIENTIFIC DISCOVERY. 



was but slightly larger than the shot Itself, showing it experienced but 

 little resistance in its passage. A repetition of the experiment, with 

 the target inclined at an angle of 45, produced the same result ; the 

 target being penetrated, and much more injured, than when vertical. 

 It should have been stated, previously, that the target was 96 inches 

 long, by 42 inches wide. In a comparative experiment, to test the 

 value of India-rubber as a resisting agent, a target was made with four 

 single iron plates, each one inch thick ; the results, as observed by 

 competent witnesses, did not vary materially from those obtained with 

 rubber, and little value is attached to it as a disperser of the force of 

 shot. 



Trial of the largest British Ordnance hitherto constructed. The 

 following account of the most powerful gun which has as yet been 

 constructed in Great Britain, is taken from the London Times. Tin; 

 gun is of wrought iron, with a caliber of 13 inches, just about the 

 same as that of Ericsson's wrought-iron guns, which are to be used in 

 arming the Dictator and Puritan : 



" The trial," says the Times, " was to test the powers of the greatest 

 gun yet forged by Sir William Armstrong, a 600-pouuder termed 

 the ' Big Will, 1 against one of the thickest and most perfect plates which 

 Messrs. Brown & Co. have as yet produced for actual armor-plating. 

 The plate in question was no less than 11 inches in thickness, a 

 sample of one of many of the same enormous strength made by Messrs. 

 Brown & Co. for the Russian Government, to plate the sea faces of 

 some of the most important and exposed of the Cronstadt forts. Ac- 

 cording to the theory of the iron plate committee, that the strength of 

 an iron plate increases as the square of its thickness, this 11-inch mass 

 was equal in strength to no less than six plates of the famous Warrior 

 target ; yet before the experiment commenced, not the slightest 

 doubt was entertained that the GOO-pounder would utterly smash it, 

 if fired with a 600-pound shot. The real interest of the experiment 

 consisted in ascertaining, first, whether the same destructive result 

 would be gained by using the gun as a smooth-bore with a steel shot 

 of half the weight ; secondly, how the gun would stand the tremendous 

 charge of 00 pounds of powder ; and thirdly, whether the fracture of the 

 plate would show that even Messrs. Brown could not manufacture one 

 of 11 inches in thickness perfect throughout. These were the three 

 points really at issue, and the solution of these was looked forward 

 to with keen interest by all the officers on the ground. The first and 

 only shot, we are happy to sav, settled them all in the most satisfac- 

 tory manner, and proved the enormous advantage of steel shot, the 

 strength of the gun, and the excellent manufacture of the plate. The 

 plate or slab of iron was four feet long by '.}.\ feet wide, and was un- 

 impaired in its strength by a single bolt-hole or fastening. It was 

 held up vertically against two 12-inch beams of solid oak, to which it 

 was fastened by railway iron, passing up its face on either side. Be- 

 hind it, and in support of the oak beams, was the Fairbairn target of 

 5-inch plates and a 1-inch inner skin, with the usual massive frame- 

 work of iron rib beams. This target, however, did not support the 

 plate to be fired at, but only the beams of oak which held it in posi- 

 tion. There was an interval of 12 inches between the plate and the 

 Fairbairn target, which was left purposely that the former might do its 



