booming of the guns, the never-ending crash of exploding shell. Once he saw a heavy German shell in the air—he glimpsed it at that culminating point of its trajectory where the shell begins to lose its initial velocity and turns earthward again. It was a curious experience, which many airmen have had, and quite understandable, since the howitzer shell rises to a tremendous height before it follows the descending curve of its flight.

He paid a visit to the only cloud that had any pretensions to being a cloud, and found nothing. So he went over the German lines. He passed far behind the fighting front and presently came above a certain confusion of ground which marked an advance depot. He pressed his foot twice on a lever and circled. Looking down he saw two red bursts of flame and a mass of smoke. He did not hear the explosions of the bombs he had loosed, because it was impossible to hear anything but the angry "Whar—r—r—!" of his engines.