in the water, hinted at the perils that were constantly threatening our forces. In the tense imagination of the lookouts floating spars or other débris easily took the form of periscopes. Queer-looking sailing vessels, at a distance, aroused suspicions that they might be submarines in disguise. A phosphorescent trail in the water was sometimes mistaken for the wake of a torpedo. The cover of a hatchway floating on the surface, if seen at a distance of a few hundred yards, looked much like the conning-tower of a submarine, while the back of an occasional whale gave a life-like representation of a U-boat awash--in fact, so life-like was it that on one occasion several of our submarine chasers on the English coast dropped depth charges on a whale and killed it. But it was the invisible rather than the visible evidences of warfare that especially impressed our men. The air all around them was electric with life and information. One had only to put the receiver of the wireless to his ear to find himself in a new and animated world. The atmosphere was constantly spluttering messages of all kinds coming from all kinds of places. Sometimes these were sent by Admiral Bayly from Queenstown; they would direct our men to go to an indicated spot and escort an especially valuable cargo ship; they would tell a particular commander that a submarine was lying at a designated latitude and longitude and instruct him to go and "get" it. Running conversations were frequently necessary between destroyers and the ships which they had been detailed to escort. "Give me your position," the destroyer would ask. "What is the name of your assistant surgeon, and who is his friend on board our ship?" the suspicious vessel would reply--such precaution being necessary to give assurance that the query had not come from a German submarine. "Being pursued by a submarine Lat. 50 N., Long. 15 W."--cries of distress like this were common. Another message would tell of a vessel that was being shelled; another would tell of a ship that was sinking; while other messages would give the location of lifeboats which were filled with survivors and ask for speedy help. Our wireless operators not only received the news of friends, but also the messages of enemies. Conversations between German submarines frequently filled the air. They sometimes attempted to deceive us by false "S.O.S." signals, hoping that in this way they could get an opportunity to torpedo any vessel that responded to the call. But these attempts were unsuccessful, for our wireless operators had no difficulty in recognizing the "spark" of the German instruments. At times the surface of the ocean might be calm; there would not be a ship in sight or a sign of human existence anywhere; yet the air itself would be uninterruptedly filled with these reminders of war.