horizontal joints. Eight thicknesses of this plate make up the compact resistance on every side. The plates are firmly riveted together, though not so closely as to allow of no spring; and they so lap over each other that there will be only a single joint at one place. Thus the turret will be eight or nine inches thick on every side, but in addition to this Capt. Ericsson will place on the side in which the two port-holes are bored, which will of course be toward the enemy and will receive a large proportion of the enemy's shot, an additional thickness or shield of two inches of iron, so that on the fighting side the turret will present a thickness of eleven inches of wrought iron. The gunner inside a defence of this character will feel as secure as an ancient Knickerbocker in his easy-chair, while heavy balls are striking all about him, within a few feet outside, with all the force which the enemy's best guns can give them. A shell-proof flat roof of perforated plateiron, placed on forged beams inserted six inches down the cylinder, covers the top. Several sliding hatches in this give access to the turret from outside. The sides of the turret are perforated with holes of an inch diameter, to give light, and are useful, in case the battery is boarded, for musketry fire. A turned composition ring is inserted in the deck, upon which the circumference of the turret rests, but its weight is mostly upheld by a vertical shaft, ten inches in diameter, which rests firmly in a cup on a bracket attached to the main bulkhead of the vessel. A spur-wheel, six and a half inches in diameter, eleven inch face, moved by a double-cylinder engine, turns the turret around and the guns as well, directing them to any point of the compass. A rod connected with the reversing gear of the engine will enable the gunner to control the aim, so that one officer has charge of both turret and guns, and the greatest possible accuracy may be attained in firing. The armament of the vessel will consist of two Dahlgren guns of the heaviest calibre. They will be parallel, and the turning of the turret will give them their direction. The two port-holes are within about two feet of each other on the same side, and about three feet from the deck. The guns will move on forged iron slides across the turret, the carriages, which are wrought iron, being made to fit them accurately. When the gun is run in for loading, a pendulum of wrought iron will fall over the port-holes, so that no ball can enter. The guns will carry either shell or solid shot. Engineers and military men consider the eleven-inch shell, at short range, as one of the most terrific weapons introduced into practice. There is nothing that has yet been brought into practical operation that will equal them in destructive power. They will burrow under an enemy's works, and when they explode they produce an effect in the vicinity like an earthquake. The Government has also ordered for Capt. Ericsson some wrought-iron shot, very handsomely turned. The engines have been placed in the vessel for some time. They were laid two months and eight days from the time of laying the keel. They work very satisfactorily, a speed of sixty turns a minute having been already attained. The cylinders are forty inches in diameter, and twenty-two inch stroke. The boilers are on the horizontal tabular plan. One of the most important results attained in the construction of the vessel has been the entire protection of the engines, propeller, rudder, and even anchor, from shot. The propeller and rudder are both hidden under the upper hull, and the anchor is protected by the forward projecting part of the upper hull within, while it is suspended in a circular chamber, open from below, so that the men may let out or haul in the anchor quite unexposed. The ends of the vessel being sharp and of such immense force, the battery is, incidentally — for there was no stipulation that the inventor should include this advantage--one of the most powerful steam-rams that was ever built. The plate is perfectly straight on the two sides toward the end, so as to bear any shock, and the immense weight of the upper hull and deck — a weight of at least five hundred and fifty tons — would operate in one direction in the use of the vessel for this purpose. The deck being perfectly water-tight, and having no railing or bulwark of any kind, but coming flush with the top of the upper hull, admits the washing of the sea over it at liberty. The turret can also be made water-tight. The vessel will ride easily in the water, because the sea, instead of breaking against it, will pass over it as in the case of a raft. The vessel is on the principle of a life-boat, in the respect of the waterproof deck; and it is believed that it will live in a sea where a common vessel would swamp. It is expected to attain a speed with her of eight knots an hour. There have been only one hundred working days since the date of the contract for this battery. There has been only one establishment engaged in turning out the immense armor-plate, that of Abbott & Son, of Baltimore. If any other establishment could have been employed in this, the work might have been completed even sooner. The manufactory of Abbott & Son has been wholly given up to this work. Other portions of the plating have been made by Messrs. Corning, Winslow & Co., and Holdane & Co. Still the rapidity with which it has been completed shows what the country is capable of, if its energies were aroused. It is stated that the speed with which the work has been carried on would have been utterly impossible in England.
--N. Y. World, January 31.