The United States Navy appears to have figured chiefly through its destroyer fleet. It has been stated that half the number of sailors who were in the navy when we entered the war were sent to European waters. The system of training them involves a number of training-bases in Europe constantly filling up from American drafts. Each new destroyer that steams to Europe from our shores in due course sends back some of her men to form a nucleus for the crew of another new destroyer turning up in American waters. Their places are taken by drafts from the training-bases in Europe. The destroyer referred to as turning up in this country makes up her complement from the battleships and other naval units here. The training-bases in this country are established at Newport, Chicago, San Francisco, and Pelham Bay, N.Y. Here the men have many months' instruction. As their training approaches completion they are sent where needed, and thus the work of creating an immense army of trained seamen qualified for any sort of a task proceeds with mechanical precision. Submarine hunting is very popular with our young jackies, and great is their satisfaction when some submarine falls victim to their vigilance, their courage, and their unerring eyes. "But," said a young sea officer not long ago, "the submarine is a difficult bird to catch. He holds the advantage over the surface craft. He always sees you first. Even when he is on the surface he is nearly awash, and when submerged only his periscope appears above the water. The submarine is not after animals of our breed--destroyers--and when he can he avoids them. We may go several weeks without putting an eye upon a single U-boat. When we do there is action, I can tell you. We start for him at full speed, opening up with all our guns in the hope of getting in a shot before he is able to submerge. But you may believe he doesn't take long to get below the surface. Anyway, the sub doesn't mind gun-fire much. They are afraid of depth charges--bombs which are regulated so that they will explode at any depth we wish. They contain two or three hundred pounds of high explosive, and all patrol vessels and destroyers carry them on deck and astern. When we see a submarine submerge we try to find his wake. Finding it, we run over it and drop a bomb. The explosion can be felt under water for a distance of several miles, but we have to get within ninety feet of the hull to damage it. This damage may or may not cause the undersea boat to sink. Inside of ninety feet, though, there isn't much doubt about the sinking.