In 1876 Mr. Whitehead produced an improved torpedo. It had a diameter of only 14 inches, a speed of 18 knots for a distance of 600 yards, and a charge of 26 lbs. of gun-cotton. It was fitted for the first time with the “servo-motor,” which, as Lieutenant Armstrong remarks, makes the steering almost as perfect as if a mannikin helmsman were steering the torpedo from the inside. In 1884 it was still further improved. The speed was raised to 24 knots and the explosive charge was increased. In 1889 the speed was again raised to 29 knots for 1,000 yards, and the charge was 200 lbs. of gun-cotton. The Whitehead torpedoes carried in His Majesty’s ships to-day are of two dimensions:— Diameter. Speed. Range. Charge. in. kts. yds. A 18 32 600 200 lbs. gun-cotton B 14 30 600 80 lbs. gun-cotton Several different patterns of Whitehead torpedoes are turned out at the various factories, but they all resemble each other in their main characteristics. [Illustration: MARK IX., R.G.F., FOURTEEN INCH WHITEHEAD TORPEDO. ] The “baby,” as the seaman calls it, is a cigar-shaped object made of steel or of phosphor-bronze. It is divided into compartments, and in the foremost of these is placed in war time the explosive charge. At the head is the end of a pointed rod penetrating the explosive, and when the torpedo comes into contact with a solid object, the point of the rod is driven in against a detonator which explodes the charge and tears a hole in the ship’s bottom. Abaft the explosive chamber comes the air chamber; herein is stored the compressed air which acts as the motive power of the torpedo. Behind this is the balance chamber, where all the automatic steering apparatus is fixed. Abaft this are the engines; these are worked by the compressed air from the air chamber and revolve a shaft, on to the end of which are two screw-propellers working in opposite directions. Furthest aft of all is another hollow air compartment termed the buoyancy chamber. There are four rudders, two horizontal for steering from right to left, and two vertical for maintaining the proper depth. One might be forgiven for thinking that the narrower the fore part of the torpedo the faster would be its speed; a study of fishes shows, however, that this is not Nature’s principle, and the Whitehead is therefore thicker at the fore than at the tail; technically, it has “a full entrance with a very fine run.” The Whitehead is divided into eight sections, containing:— 1. The firing arrangement. 2. The explosive chamber. 3. The air chamber. 4. The “balance” chamber. 5. The engine chamber. 6. The buoyancy chamber. 7. The bevel wheel chamber. 8. The horizontal and vertical rudders and propellers. 1 AND 2. THE FIRING ARRANGEMENT AND EXPLOSIVE CHAMBER.