Up and up they arose, the smaller planes flying high as a protection to the more cumbersome machines of the bi-motored type. And soon the squadron, the largest that had yet ascended from Camp Lincoln, was hovering over the German lines.
The Huns seemed to realize that something more than an ordinary attack from the air was impending, for soon after the anti-aircraft guns began firing a swarm of German aviators took the air, and there was no shirking battle this time. The Huns so evidently felt the desperate need of driving away their attackers, that this, more than what the major and lieutenant had said, convinced Tom and Jack that they were at last on the track of the big gun.
Of course the two boys could not communicate with one another, but they said afterward that their thoughts were the same.
The battle of the air opened with a rush and a roar. The Germans, though outnumbered by their opponents, did not hesitate, but came on fiercely. They attacked first the big photographing planes, for they realized that these were the real "eyes" of the squadron. The impressions they received, and the views they carried back, might mean the failure of the German plans.
But the French were ready for this, and the
