In projecting from above water, an iron carriage is used, which is fitted with a frame in which the torpedo rests. The outer end of this frame is provided with a lip a few feet long, by means of which the rear end of the torpedo is slightly canted up on leaving the frame, preventing undue strain on the extreme end. The frame is mounted in the carriage in such a way that it can be elevated or depressed by means of a screw, like a gun. The torpedo is ejected by means of a piston as before, the carriage being provided with a small reservoir of compressed air so that it may be moved to any point aboard ship. To project from the surface, no tube is necessary; all that is required is to set it for the depth, point it, and turn back the lever by hand, when it starts off of its own accord. For discharging from boats, the torpedo is either mounted on its carriage forward or carried in iron slings suspended from davits. In the latter case the davits are pivoted, so that normally the torpedo rests in a cradle on deck; but the cradle being removed, the davits are swung over, lowering it to about two feet below water, where it is held securely until discharged. The propeller is worked by means of a pair of Brotherhood engines, working to 60 indicated horse-power and giving 1000 revolutions a minute. Weight of charge, 33 lbs. gun-cotton; weight of torpedo, 500 lbs. THE LAY TORPEDO. The shape of the Lay torpedo is quite similar to that of the Whitehead, although it is considerably larger. As in the Whitehead, the forward section forms the explosion chamber. Next abaft this is a chamber for holding the gas reservoirs, carbonic-acid gas being the motive power. Next aft is the compartment for holding an electrical cable, which forms a constant connection between the torpedo and the operator. In rear of this is the compartment for the engines and steering apparatus. These sections are separated from each other by water-tight bulkheads. The torpedo is propelled by double screws, the propellers working in opposite directions and being placed one abaft the other, the shaft of the forward one being hollow and that of the after one passing through it. The torpedo has four horizontal fins or wings, two forward and two aft; these wings are mounted on shafts or spindles passing transversely through the boat. A guide-rod or short staff is provided at each end of the torpedo to enable the operator to regulate the course. At night lanterns are hung on these rods. The electrical cable, made up of two insulated wires, is wound on a reel, and pays out through a hole in the bottom of the compartment as the boat advances. By means of one of these wires the boat is started, stopped, and steered, and by the other it is fired. [Illustration: Lay Torpedo.]