Page:Air Service Boys Over Enemy's Lines.djvu/134

126 of Tom Raymond to allow such a thing to occur and be kept from doing his share of the fighting.

When Tom swung around to face the rear, and actually started to run toward the oncoming foe, Jack knew what was expected of him. He must man the gun, and prove how well he had learned his lesson when at school at Pau and at Casso.

No longer could they expect to be guided by sounds. Their own motor thundered so loudly that every other sound was deadened. They must depend on eyesight alone to tell them when they were nearing the oncoming Fokker craft. Perhaps the first indication they would have of its presence would be the flash of its quick-firing gun, spattering bullets around them like hail.

So Jack strained his vision to the limit. He was eager to discover the enemy before they themselves were seen. Much might depend on who fired first, in a duel of this kind.

Suddenly the gun began to bark after its own peculiar way. Jack believed he had glimpsed something moving, and was sending forth a storm of lead in the hope of a lucky hit that would crumple the other machine up and put an end to that peril.

Tom held the course. He knew that every