MECHANICS AND USEFUL ARTS. 75 



curely bolted cm, one over the other, with the joints overlapping each 

 other. Within this there is a lining of iron one inch thick, thus giving 

 nine inches of solid iron. It rests on a bed plate, or rather ring, made 

 of composition, which is securely fastened to the deck. To help sup- 

 port the weight, which is about a hundred tons, a vertical shaft ten 

 inches in diameter is attached and fastened to the bulkhead. The top 

 is covered with forged iron beams and perforated iron, shell proof. 

 The top is perforated to allow the smoke of the guns, and even more, 

 the concussion of the air, to pass off. The top has also some small 

 sliding hatchways composed of two-inch plate iron, to serve as en- 

 trance-ways. 



The turret has two circular port-holes, three feet above the deck, 

 and just large enough for the mouth of the gun to be run out. 



For a contest with iron-clad ships carrying the heavy ordnance re- 

 cently devised in Europe, Captain Ericsson proposes to dispense with 

 two of the outer plate rings of the turrret, and to attach in their place 

 staves of rolled iron four inches thick, thus presenting an aggregate 

 thickness of ten inches of plating, besides the internal skeleton. 



The Armament. The battery will carry two very heavy rifled 

 guns. The carriages, of wrought iron, will run back on iron slides, 

 which are made to fit very accurately. The whole turret, by an ar- 

 rangement worked by a special engine, is made to revolve ; and the 

 operator within, by a rod connected with the engine, is enabled to 

 turn it at pleasure. 



In action the guns will be loaded and run out while the portholes 

 are away from the enemy. When ready the turret will be turned as 

 nearly accurate as possible. By nicely adjusted wheels, a very pre- 

 cise aim is quickly obtained, the gun fired, and instantly the turret is 

 turned to bring the gun out of danger. The gun is then drawn in 

 and loaded as before. While one gun is being aimed and discharged, 

 the other is loading, so that almost a continuous discharge can be kept 

 up. 



The cylinders of the engines are forty inches in diameter and 

 twenty-two-inch stroke ; the boilers being horizontal. It should also be 

 stated, that speed is not a primary object of the builder, the vessel 

 being strictly a battery, and not an iron-clad ship. The blowers for 

 the boilers and for ventilating the ship will be worked by an indepen- 

 dent small engine, which will also furnish the power for turning the 

 turret. 



This battery, so far as can now be judged, seems to have no vulner- 

 able part, save the port-holes, which are exposed only for about half a 

 minute in firing. Its sharp and massive iron prow will enable it to 

 sink any ordinary vessel with perfect ease. In case it is boarded no 

 harm is done. The only entrance is at the top of the turret, which 

 cannot be easily scaled, and even then but one man at a time can de- 

 scend. There are no places in the deck where an entrance can be 

 forced, so the boarding party may stay until the sea washes them off, 

 or the sharp-shooters assist their departure. 



