ent after him like lightning, bent on attaining his goal.

The Hun was scrambling desperately in the endeavor to get on his feet.
Tom hurled him over, and closed with him. Finding his escape thus cut
off, the other commenced to fight like a tiger, clawing and struggling
furiously.

They had it "hammer-and-tongs" for a brief space of time. Then Tom
slipped and lost his grip, upon which the other rolled over several
times, got to his knees, then his feet, and started to run.

But he counted without reckoning on the staying qualities of the
American. Tom had always been called a "sticking-plaster" by his fellow
players on the football field. He was not to be counted out of the game
until the last whistle sounded and the referee's falling hand closed the
fun.

So he was after his man with grim determination not to let him get away.
Having gone to so much trouble, and received in addition several
scratches in the contest, he meant to keep everlastingly at it.

The Boche dodged to one side, as there were men running toward them, and
already several lights had sprung up. Tom was close at his heels, and
gaining rapidly, being spurred on by an ambition to complete the good
work he and Harry had started.

He saw the spy glance back over his shoulder. The situation must have
appeared very grave to the other, who could expect to meet with short
shrift if caught in the act of trying to destroy the hangars and planes
of the American aviators in this bold fashion.

Just then Tom saw the man raise his arm. Guessing what he intended to
do, the Yankee air pilot dodged just in time. Some object went hissing
past, close to his head. An instant later there was a loud explosion in
his rear that seemed to make the very air quiver.

Of course the Boche had hurled a grenade with the intention of making
further pursuit on the part of his persistent adversary impossible.

Tom hoped that was the extent of his supply of such ammunition, for he
might not be quite so successful in avoiding the bomb another time.

Again was the fleeing spy compelled to whirl aside because of
threatening peril ahead. Dodging in and out between the khaki-colored
canvas field hangars he sought desperately to throw Tom off his track;
but no hound ever followed its quarry with more pertinacity than the
Yankee air pilot followed now.

Then something happened. Tom came in collision with a runner, so that
the two of them fell headlong to the ground. By instinct To