TORPEDO. 355 TORPEDO. fire gun sounded their death-knell. The Harvey towing torpedo (and its modifications) was towed in a spar at the end of a hawser, its shape and steering vanes keeping it well out on the quarter of the ship using it. Its defects are ap- jjarcnt and it is obsolete. The extra-mohile or locomoiii^c torpedo has an external source of pow- er supplied through wires which are also used in carrying the steering force. Some few of these are still 'ollicially' in service, such as the Brennun and Hims-Edison. but they are not nuich in favor. The Brennan is propelled by two wires which are reeled up in the torpedo. By hauling on them they unreel and rotate twin screws. Steering is effected by varying the tension on the port or starboard wire. The Sims-Edison torpedo is pro- pelled and steered by electricity from an external source which is supplied to the torpedo through a wire cable which is unreeled as the torpedo advances. The automobile controlltihle torpedoes, of which there were many varieties, carried their own source of power, which was usually com- pressed air or carbonic acid gas, and were all electrically steered, the current passing through a light cable which was unreeled as the torpedo moved ahead. are identical in general design and similar as re- gards details, though the body of the Whitehead lias a steel shell or outer case, while that of the Schwartzkopf is made of bronze. The details of a Whitehead torpedo are shown in the accom- panying plana. In Fig. 1, A is the war-nose; 15 is the icar-liead (an exercise head without explosive charge or war-nose is used in onlinary torpedo target practice) ; C is the air-flunk con- taining the compressed air — its shell is tliicker than that of the rest of the torpedo; P is the guide stud for holding the tor|)edo in position in the tube; Q is a strengthening bund to sup- port the guide stud; Vis the balance ehamber ;V is the engine compartment ; G is the tail; H is the tail-frame; 1 is the firing-pin; 2 is one blade of the releasing screw. B, the icar-liead, contains the explosive charge, 3, of wet guncotton, while 4 is a small priming charge of dry guncotton in a her- metically sealed case inserted in the front end of the war-head before screwing in the war-nose. In Fig. 2, 6 and 8 are the charging and slop valves for charging the torpedo; T is the depth regu- lator which connects by the bell-crank lever M to the regulator spring, which is pressed by the hy- draulic piston, 16; the hydraulic piston receives Fig. 1. WHITEHEAD TOEPEDO. The projectile type of uncontrollable torpedoes is fired from a submarine gun (q.v.). It has never proved satisfactory as a weapon, but it received its most successful development at the hands of Ericsson, who was able to give it a reliable range of about 150 yards. The short range of the submarine gun was its fatal defect and caused its condemnation. Rocket torpedoes have usually been fitted to move along the surface of the water, the propelling force being the reac- tion from the gas escaping from the rear end. As they are very erratic in their movements when the water is smooth and cannot be used at all when it is rough, they have never had much vogue. Submerged torpedoes propelled by rocket tubes have been even less successful ; they lack the speed of the surface type and are nearly as erratic as regards their course. Drifting tor- pedoes are merely self-acting buoyant mines set adrift. the water-pressure on its after side as the en- gine-room (F) is open to the sea; the hydraulic piston operates small levers pressing against a lever pivoted on the pendulum (17), and the motion is transmitted through the rod N to a crank and thenee to the steering engine (18), which operates horizontal rudders (not shown) by means of the rod 24 ; D is the operatiiig valve group which controls the supply of air to the engine, W; 10 is the starting lever; E is the re- leasing mechanism ; K is the Ohry gear, in which 20 is the gyroscope wheel; 13 and 14 are the propellers; 15 is the bevel gear, which permits the two propellers to be driven in opposite direc- tions ; and 22 are the rudders actuated by the Ohry gear. This latter by means of its gj'ro- scope wheel (which always keeps in one plane) operates the little rudders (22) and brings the torpedo back to its original direction if it is. deflected from any cause. H FlO, 2. PROPELLING AND 8TEEBING MECHANISM OF WHITEHEAD TOEPEDO. We now come to the class of moving torpedoes which is most in use. the automobile or 'fish' type. There are many varieties, but only three are actually in service, the Whitehead. Schwartz- kopf^ and Howell. The first and second of these The Howell torpedo resembles the Whitehead in all its features except the propelling mechan- ism. The forward compartment is the war-head. Next in rear is the propelling compartment, then comes the buoyancy chamber containing the
