passing over the line of the French trenches. Jack knew this from various signs, and also that in another minute they might expect to be spotted by some of the enemy searchlights. These would be unmasked, and trained on the heavens in the effort to locate the cause of that well known clattering noise above.
This speedily came about. First one long shaft of dazzling light rushed back and forth; then others joined in the hunt, until presently they focussed on the progressing two-seater pushing north.
Then began the bombardment. Numerous anti-aircraft guns were poking their noses upward in anticipation of just such a call. Their crews commenced to shower the shrapnel around and below the bird of passage, whose mission, whatever it might prove to be, could mean only evil to the Teuton cause.
All this racket was lost upon the two so far above the earth. They heard nothing of the bleat of the firing guns. Even the bursting of shrapnel went unheeded, save at a time when a shell exploded close by, and was faintly heard.
Tom was wisely taking but little chance. He maintained an altitude that prevented most of the shrapnel from coming anywhere near the plane.
They crossed the enemy front, and sped on.
