THE TORPEDO In parts of South America there lives a little fish, which, if you touch its nose, gives you a severe electric shock. The natives call it the "torpedo." When an artificial fish came to be invented, capable of giving a very nasty shock to anyone touching its snout, that name was bestowed upon it too. Even more than the submarine, the torpedo resembles a fish with its graceful outlines and its fins and tail, the chief difference being that the tail of the torpedo carries a couple of little rotating propellers. Looked at another way we may say that the torpedo is an automatic submarine. As a matter of fact, we all know it best as the weapon of the submarine. It was originally invented by an Austrian who took it to a Mr. Whitehead, an Englishman who then had an engineering works at Fiume. This gentleman took up the idea and developed it into the Whitehead torpedo, which is to-day used by half the navies in the world, the rest using something very similar. It is curious to note that the German variety is called the Schwartzkopf, the meaning of which is "blackhead." The smooth, steel, fish-like body consists of two separate parts, which can be detached from each other. The front part called the "head" is made in two kinds, the war-head and the peace-head. The former contains a large quantity of explosive and the mechanism for firing it on coming into contact with any hard body. It is only used in actual warfare. The peace-head is precisely the same shape and weight as the other but is quite harmless, so that when it is fitted to the torpedo the latter can be handled with perfect safety, a valuable feature during the frequent exercises through which our sailors go in their efforts to attain perfection in the use and handling of these valuable weapons. So much for the head. The body of the torpedo contains a beautiful little engine precisely similar to a steam-engine but on a small scale, which is driven by compressed air, a store of which is carried in a compartment provided for the purpose. Then there is an automatic steering apparatus controlled by a gyroscope, the purpose of which is to keep the torpedo steered in precisely that direction in which it is started. If any outside force, such as current or tide, deflects it from its path the gyroscope, acting through a rudder at the tail, brings it back again. Like the submarine, moreover, it has rudders which can steer it upwards or downwards and these again are controlled automatically so that having been set to travel at a certain depth the torpedo can be launched into the water with the practical certainty that it will descend to that depth and then maintain it.