Page:The Development of Navies During the Last Half-Century.djvu/239

 charges of the torpedoes and the armour we had applied would become vulnerable.' No more accurate forecast could have been made. The latest development of the Whitehead is a torpedo 18 in. in diameter, with a speed of 30 knots, and carrying 200 lbs. of gun cotton. No modification in construction could render the explosion of such a mass beneath a ship other than irresistible. Should it be otherwise, an addition of 2 in. to the diameter of the torpedo would probably allow the charge to be increased to 500 lbs., and I am quite unable to see how this could be counteracted.

In the successful application of the Whitehead torpedo much depends on the method by which it is launched from the ship or boat. It is now usually discharged, like a projectile from a gun, by means of a small charge of gunpowder, or compressed air, from a tube which it accurately fits. In most cases the tube is a few feet above the water line, and the torpedo is launched at any given moment. But it has always been considered that if it could be projected under water from a ship the apparatus would not be exposed to an enemy's fire, and the torpedo would start under more advantageous circumstances. The preliminary plunge from above water has always been trying to the mechanism contained in the interior. The difficulty under water is to get the torpedo clear of the ship when the latter is proceeding at high speed. An elongated body thrust out of a hole into water rushing past at a rate of 18 knots is naturally subjected to severe strains. It must be supported until