A, Striker which, when driven in, fires the charge; B, Safety pin, which is removed just before the torpedo is discharged; C, Detonating charge; D, Explosive-head, or war-head; filled with guncotton; E, Primer charge of dry guncotton in cylinder; F, Balance chamber; G, Starting pin; H, Buoyancy chamber; I, Propellor shaft; J, Vertical rudder; K, Twin screws; L, Horizontal rudder; M, Gyroscope controlling torpedo’s course; N, Engines propelling machinery; O, Pendulum acting on the horizontal rudder which controls the depth of submergence; P, Hydrostatic valve; Q, Air-chamber, filled with compressed air; provides motive-power for the engines; R, “Jammer” or release propellor. ] Thus guided and driven, a modern torpedo speeds swiftly and surely to its target, there to blow itself into a thousand pieces, with a force sufficient to sink a ship a thousand times its size. The Whitehead is used by every navy in the world except the German, which has its own torpedo: the “Schwartzkopf.” This, however, is practically identical with the Whitehead, except that its hull is made of bronze instead of steel and its war-head is charged with trinitrotuluol, or T.N.T., a much more powerful explosive than guncotton. After the Russo-Japanese War, when several Russian battleships kept afloat although they had been struck by Japanese torpedoes, many naval experts declared that an exploding war-head spent most of its energy in throwing a great column of water up into the air, instead of blowing in the side of the ship. So Commander Davis of the United States navy invented his “gun-torpedo.” This is like a Whitehead in every respect except that instead of a charge of guncotton it carries in its head a short eight-inch cannon loaded with an armor-piercing shell and a small charge of powder. In this type of torpedo, the impact of the striker against the target serves to fire the gun. The shell then passes easily through the thin side of the ship below the armor-belt and through any protecting coal-bunkers and bulkheads it may encounter, till it reaches the ship’s vitals, where it is exploded by the delayed action of an adjustable time-fuse. What would happen if it burst in a magazine or boiler-room is best left to the imagination. Several Davis gun-torpedoes have been built and used against targets with very satisfactory results, but they have not yet been used in actual warfare. [Illustration: Courtesy of the Electric Boat Company. Davis Gun-Torpedo after discharge, showing eight-inch gun forward of air-flask.]