“That’s our Boche friend!” exclaimed Dick Lever. “Let her go, boys! Maybe this time I’ll have the luck to get the brute!” and as the soldiers loosed their holds, the aeroplane swept forward, and then, at a quick motion on Dick’s part, soared gracefully into the air. Dick slanted swiftly upward into the gathering twilight, and soon became indistinguishable to the straining eyes of those on the ground. Only the sound of his whirring motor remained to tell them of the gallant man willingly risking his life for his country. As the sound of his motor grew fainter, the throb of another engine insensibly mingled with it, but the later comer had the irregular pulsations that all the Americans recognized as coming from a German machine. “I’ll wager anything that’s the Boche!” exclaimed Tom, and everybody there agreed with him. It was now almost fully dark, and although the boys strained their eyes they could make out nothing of the duel that was going on a mile or two above the earth. But suddenly a weird and fascinating thing happened. From out the black vault of the night sky a rippling, streaming cascade of fire leaped downward for a space, and then suddenly mushroomed out in a sparkling splash of phosphorescent light. Smaller stars and streamers spread out in all directions and gradually melted out as they fell earthward. But there remained a faint, ghostlike, unreal patch of swiftly moving light, that the breathless watchers knew must be the Boche aeroplane. “It worked!” exclaimed Frank. “That Hun aviator is done for now, because Dick can see him, and he can’t see Dick.” Even as he spoke, a stream of red fire spit viciously out from a point slightly above the German, who had now turned and was flying for dear life back to his own lines. For a space the weird attack continued, and the German, apparently giving up hope of safety in flight, turned and fired desperately toward the stream of deadly fire that marked the position of Dick’s machine gun. But suddenly, one of the deadly bullets from the machine gun got home, for the patch of light marking the Hun machine, wavered, swerved, and then dived swiftly earthward. CHAPTER X TANK AGAINST TANK A great sigh arose from the group of soldiers gazing spellbound on this drama of war. The German aeroplane fell swiftly until it was perhaps halfway to the earth, and then straightened out for a second, hesitated, and started turning over and over as it neared the uprushing earth. The top of its wings seemed fairly covered with the greenish luminous paint, that smoked and glowed and gave the ill-fated aeroplane the appearance of a gigantic pinwheel as it came hurtling earthward.