From a study of the submarine problem as it stands to-day, the one thing lacking to make the submarine sufficiently powerful to stop commerce on the high seas between countries at war is speed. We have seen from the foregoing that sufficient speed to accomplish this purpose means great additional cost, and, as the engine situation exists to-day, it may be considered that it is impossible. My own personal opinion is that we shall not see satisfactory twenty-knot submarines, let alone twenty-five-knot submarines, for a matter of several years. In the meantime the people of this country, now engaged in the gigantic conflict which is taking place across the water, are becoming much exercised as to the possibility of some condition arising which may bring about an attack upon our own country. There is a method of preparing this country with a type of submarine which may be navigated, so to speak, at much greater speed than that called for by the 1914 Congress; namely, twenty-five knots. The boats would have the further advantage in that they would be much less expensive even than the fourteen-knot submarines now called for in the latest specifications for the coast-defence type. This new method calls for the construction of a moderate-size submarine, which, for the want of a better term to distinguish it, I have called an "amphibious submarine"; that is, a submarine which may be carried on land as well as on or under the water. [Illustration: "AMPHIBIOUS" SUBMARINE Making up a train to ship a Lake submarine across Siberia during the period of the Russian-Japanese war. Note the special trucks with sixteen wheels each, used to carry the load (about 130 tons). As the Trans-Siberian road had light rails, it was necessary to design these special trucks to distribute the weight so as to carry this heavy load. It is remarkable that several of these unheard-of weights should have been transported by vessel and rail a distance of over 10,000 miles each without accident or damage. Boats mounted on trucks especially designed to pass through tunnels could be transported from one port to another at railroad speed and be ready for immediate action in defending threatened sections of the country. The Germans have since made extensive use of this method of transporting submarines, giving them access to the Dardanelles and other points not easily accessible to their submarines by water.]