"Why, his mate's alive!" almost shouted the American, more shaken by this exhibition than anything that had hitherto happened to him in his short but risky campaign along the West Front.

"Hey, there! You beast — you villain!" Almost insanely Erwin was shouting, for he was convulsed by a fury that made him for the time being oblivious to the fact that he was too far away to be heard by any one but himself.

For another instant the half alive man hung on, then was shaken loose. Down he came, passing rather close to the scouting pursuer, his arms and legs still working convulsively, and so on down to his inevitable fate. By this time, and while Erwin was recovering, the big biplane had recovered and was shooting eastward as before though with accelerated speed, being now relieved of much of its former dead weight.

Still grinding his teeth, Orris shot after the foe, determined more than ever to overtake and have it out with the inhuman beast, now alone in his flight to safety but a mile ahead.

All thought of immediate return to his own lines was lost, at least until he could wreak vengeance on the man who had just shown such inhumanity towards his own comrade and countryman.

"Curse him!" still objurgated the youth. "It would be bad enough if it was a foe — one of us that was aboard that cursed craft!" Orris expelled a deep breath, while he put on all the power his speedy plane would stand. "I'll get him even if the Boches got me!"

From the course followed by the biplane Erwin knew that he was already well to the northward of the point of his own return, provided he was able to make the trip back in safety. Also it was clear that they were now well over the rear German trenches and not very far from where Belgian territory bordered on that part of northern France — now so long held by the foe.

So swift and fast did Erwin go that the transient aid afforded by casting over the still living observer was soon more than neutralized. The boy was almost within easy range.

"Just a little further and I'll get him." So ran Erwin's thought. "But I mustn't waste ammunition. There's no knowing when or where I'll need all I've got. Curse that beast! He shall die or I'll know the reason why, even if I get into a narrow squeeze myself."

At last he felt that he might begin. He was on the tail of the biplane, though underneath. To his gratification he also saw that in nimble activity he was now the superior. And in close fighting it is the nimble, ducking, dodging, twisting machine that usually has certain advantage.