The submarine is another type of war apparatus, one the utility of which promises to be very great. It is of recent origin. At the time of the Spanish-American War there were only five submarines in all the navies of the world, and of this number three were in the French navy, one in Italy and one in Portugal. The United States was building its first one, and had not decided what type to select. At the outbreak of the Russo-Japanese War Great Britain had nine of the American (Holland) type of submarines and was building twenty more, while France had accumulated thirty-six of various types and of various grades of reported efficiency, while Germany had none. In 1914 there were nearly four hundred vessels of this type in the world’s navies, France standing first with 173. It was believed that the moral effect of the submarine would be almost as important as its physical effect in dealing with an enemy’s warship, and this idea has been justified. Some persons maintained that fights of submarines with each other might take place, each, like the Kilkenny cats, devouring the other. But the fact is that when submerged the submarine is as blind as the traditional bat. Its crew cannot see any object under water, and is compelled to resort to the use of the periscope, which emerges unostentatiously above the water, in order to see its own course. It is known that the periscope is the eye of the submarine, and naturally attention has been paid to the best way of destroying this vital part of such boats. Recently, grappling irons have been devised for use from dirigibles, which are expected to drag out the periscope as the dirigible flies above it. Careful plans for torpedoing submarines also have been made, but their effectiveness likewise remains to be demonstrated. Submarine builders have naturally held the view that the submerged boat could not be seen. But it has been discovered that from a certain height an observer may trace the course of a submerged submarine with as great accuracy as if it were running on the surface. It is found that the submerged boat can readily be seen from the dirigible and the aeroplane. On the other hand an anti-balloon gun has been devised which can be raised from the submarine when it comes to the surface, and used against the hostile airship. UNDER-WATER WARFARE The submarine is supposed to have its most important field of operation against a fleet of battleships and cruisers besieging a seaport city. These great war craft, covered above the waterline with thick steel armor, are vulnerable below, and a torpedo discharged from a torpedo boat or an explosive bomb attached to the lower hull by a submarine may send the largest and mightiest ship to the bottom, stung to death from below.