MECHANICS AND USEFUL AKTS. 107 



own work, if it could, unaided. The proceedings were commenced by 

 firing two cast-iron round shot of 300 pounds 1 weight, levelled at 200 

 yards range, against a *' dummy' 11 target placed close alongside the 11- 

 inch plate for the purpose of determining the exact degree of elevation 

 to be given to the gun. Both these were fired with the enormous 

 charges of 90 pounds of powder. Such charges even with 600-pounders, 

 would not be used in actual warfare, and for experimental purposes 

 were objectionable, as it seemed to make it almost as much an effort 

 to destroy the gun as the target. The precise range having been as- 

 certained, 'Big Will' was again stuffed* with a sackful of powder, 

 but, instead of a cast-iron projectile, was loaded with a steel round 

 shot of 314 pounds' weight, and levelled against the target. This shot 

 struck the very center of the plate with a terrific crash, at a velocity 

 of 1,560 feet, and at one blow closed the experiments for the day. 

 Nothing further remained to be accomplished, for the target was gone. 

 Never, probably, has a more tremendous blow been struck by human 

 agency. The mass of steel driven by the tremendous charge of pow- 

 drr must have struck the target with a power almost inconceivable, 

 for everything went down before it. The solid oak beams behind the 

 plate were crushed into splinters, and the plate itself hurled bodily 

 back against the Fairbairn target and split into two pieces, one huge 

 piece being filing away to the right and the other to the left, and all 

 this before the shot had time to penetrate to a greater depth than 4 

 inches. The 11-inch plate, in fact, had not sufficient stability to re- 

 ceive the blow aimed at it ; it was torn apart by the tremendous force 

 with which it was jammed against the Fairbairn target behind, and an 

 examination of the fracture showed that its manufacture was admirable. 

 Fourteen feet in front of the target lay the steel shot, much flattened, 

 and cracked, but evidently as good metal of its kind as Mr. Brown's 

 plate itself. A close examination of the gun was next made by the 

 Inspector of Artillery, and it was found to be wholly uninjured. Not- 

 withstanding the use of steel round shot in a rilled gun, the grooves 

 of the rifling remained as sharp and fine as ever, and only one feeling 

 seemed to be entertained on the ground as to the strength of the gun 

 and the excellence of the plate." 



Construction and Trial of a new Monster Gun. During the past 

 year a cannon of 20-in jli caliber, the largest piece of ordnance ever 

 constructed and mounted, has been successfully cast according to the 

 plan devised by Capt. llodirun, at the Fort Pitt foundry, Pittsburg, 

 Pa. The amount of metal used in the casting was 160,000 pounds, 

 and the time of cooling was upwards of two weeks. Another gun 

 of a similar caliber, but weighing some eight tons less, was also suc- 

 cessfully cast subsequently. 



The first-named gun, which is 20 feet 3 inches in length, and 

 weighs 58 tons, is mounted at Fort Hamilton, New York Harbor. 

 The carriage on which it rests is constructed wholly of iron, has 

 an extreme length of 22 feet a hight of eight feet and eight 

 inches, and weighs 36,000 pounds, or 18 tons. The trunnions of 

 the gun are 18 inches in diameter. The shot intended for this 

 enormous piece of ordnance weigh 1,080 pounds each, and are 

 handled by machinery. The location of the gun is not in the fort, 

 or very near to it, but amongst a tier of 15-inch guns which ex- 



