62 ANNUAL OF SCIENTIFIC DISCOVERY. 



comparison made between the two different kinds of ordnance as 

 to rapidity of fire. It lias always been held that the one great 

 advantage of the breech-loader was its superiority in handiness and 

 quick firing. The result of this trial does not, however, confirm this 

 opinion. The artillery-men were ordered to fire twenty rounds from 

 each gun as rapidly as they could be served. The Whitworth gun 

 finished the twenty rounds first, completing the task in thirteen min- 

 utes ; the Armstrong followed two and a half minutes later. This su- 

 periority was attributed to the simplicity of the loading and serving 

 the Whitworth gun, the drill being, in fact, precisely the same as in 

 working one of the old smooth-bore guns ; whereas the Armstrong 

 drill requires three or four extra movements. All the guns were fur- 

 ther tried by firing from each one hundred consecutive" rounds. The 

 Armstrongs were fired with lubricating wads, and were also washed 

 out and had their breech pieces changed as often as they became 

 heated so as to be unsafe ; the Whitworths all completed their one 

 hundred rounds without being washed out at all, and without using 

 any lubricating wads. It was remarked, too, that the loading was as 

 easy at the last round as at the first. 



New Rockets. Lieut. Samuel Parlby, of the Bengal Artillery, has 

 recently published a paper on the use of rockets for war purposes, in 

 which he says, that it is perfectly practicable to produce rockets of one 

 thousand pounds weight, which can be thrown with equal exactness as 

 shells from mortars. One of these falling upon the deck of a ship, he 

 claims, would immediately destroy it. 



American Iron-clad Vessels. During the past year, the United 

 States Government, encouraged by the success of the Monitor, built 

 and modeled by Capt. Ericsson in 1861, have caused to be constructed 

 nine additional iron-clad vessels for use on the Atlantic coast ; all of 

 them being built on substantially the same plan as the Monitor, but 

 rendered more formidable both for attack and defence. The follow- 

 ing are the details of the construction of one of the largest of these 

 vessels, viz., the Weehawken : Extreme length of armor two hun- 

 dred feet ; extreme length on water-line one hundred and ninety feet ; 

 extreme breadth over armor forty-six feet ; breadth of luoulded beam 

 thirty-seven feet. The bulwark armor-timbers are oak, seventeen 

 inches in thickness. The plating of the bulwarks is five inches in 

 thickness, in layers of one-inch plates, planed at the edges and break- 

 ing joints. This armor extends three and one-half feet below the 

 water-line, and projects three feet eight inches beyond the hull proper. 

 The deck beams are of oak, twelve inches thick, covered with pine 

 planking seven inches thick, and over these two courses of half-inch 

 plates are fastened. 



The Weehawken is provided with one revolving turret of twenty- 

 one feet internal diameter, nine feet height, and covered with eleven 

 courses of one-inch wrought-iron plates. This turret rests on a flat 

 ring of gun-metal, and revolves on a central shaft one foot in diame- 

 ter. The armament of the turret is two fifteen-inch Dahlgren guns, 

 manufactured at the Fort Pitt foundry, Pittsburg, Pa. The pilot- 

 house is round like the gun turret, and in this respect is an improve- 

 ment over the square pilot-house first built for the Monitor. The 

 smoke-pipe is shot-proof, eight feet in height, six inches in thickness, 



