MECHANICS AND USEFUL ARTS. 21 



it -weighed only 1| ton. In the Paris Exhibition, in 1855, there -were 

 much larger bars, but still nothing that could compare in weight 

 with the gigantic bars above mentioned. As the public mind is at 

 the present time so much interested in everything relating to armor- 

 plates, we present a description of the process by which the two great 

 plates above referred to were manufactured. The metal consisted of 

 " best new scrap," obtained from a mixture of Swedish, Shropshire, 

 and Derbyshire refined iron. It was balled under a four-ton steam 

 hammer, piled under a six-ton, and rolled into bar, re-rolled into 

 slabs, all crossed, then rolled into " moulds," and lastly rolled into 

 the finished plates. There were 360 layers in the 6^-inch plate. 

 The expense of manipulating such enormous masses of iron as these 

 armor-plates is necessarily very great ; and the present cost of them 

 ranges between $175 and $225 per ton. The display of bars, rails, 

 and girders, in the Exhibition, was very fine and extensive ; and in 

 no branch of iron fabrication has greater progress been made within 

 the last few years. The mill-power required to produce some of 

 these articles must be enormous, but we are probably far from having 

 reached the maximum limit. Among the curiosities in this depart- 

 ment shown, probably, as evidences of what could be done were 

 a rail 117 feet long and 5 inches deep, and a tension bar for girders 

 83 feet long, I foot wide, and 1 inch thick ; both sent by the Butterley 

 (English) Company. Another company exhibited two rails of the 

 following dimensions: One 53 feet 6 inches long, 4| inches across 

 the head, and 10 inches deep ; the other 31 feet 6 inches long, 5 

 inches across the head, and 15 inches deep. The Austrian Society 

 of State Railways exhibited specimens of rails, some with the head 

 of granular and the foot of fibrous iron, and others of puddled steel. 

 This is a great manufacturing company, established in 1855, with the 

 view of producing everything required for the use of railways. They 

 not only smelt and manufacture iron, but meddle with copper, lead, 

 gold, silver, paraffine, etc. How far this system is founded on correct 

 economical principles the future will decide. 



A collection of architectural irons from France indicated, what is 

 generally believed to be the fact, that iron is much more extensively 

 used in that country for building purposes than in England. Of 

 forged iron, two objects were preeminently worthy of notice, both by 

 the Mersey Steel and Iron Company, of England. One of these was 

 a monster engine-shaft, weighing about twenty-five tons ; the other 

 was an armor-plate bearing the following inscription : " This armor- 

 plate, 21 feet 3 inches long, 6 feet 3 inches wide, 5 inches thick, hav- 

 ing a superficial area of 133 feet,-weighing upwards of 13 tons, was 

 forged at the Mersey Steel and Iron Works, Liverpool, and has been 

 neither smithed nor tooled since it left the steam-hammer. This 

 plate would have been made 15 feet to 20 feet longer if space could 

 have been obtained." The same company also exhibited a monster 

 wrought-iron muzzle-loading gun, called the Prince Alfred, and 

 forged hollow by a process patented by the superintendent of the 

 works, Mr. W. Clay. This gun is 12 feet long, 35 inches in diameter 

 at the breech, 18 inches at the muzzle, 10^-inch bore, and weighs 10 

 tons. The rifling consists of twelve shallow grooves, making one 

 turn in 30 feet. Before being rifled it was fired with a 140-pound 



