eeding line trenches, they looked down through the glass windows in
the plane to make their observations. There was a camera attached to
the plane, and though they could each make use of it, but they were not
skilled in this work.

It was impossible for them to talk to one another now, as Jack had the
motor going almost full speed, and the noise it made was deafening, or
it would have been except for the warm, fur hoods that covered the ears
of the fliers. They were warmly dressed for they did not know how high
they might ascend, and it is always cold up above, no matter how hot it
is on the earth.

Up and up they climbed, and then they flew on and over the enemy lines,
keeping close lookout for anything unusual below that would indicate
the presence of the battery. Behind them, and off to one side, a fierce
aerial battle was going on.

Tom and Jack were eager to get into this and do their share. But they
had orders to make their observations, and they dared not 'refuse. They
could tell by looking back every now and then that the affair was going
well for the Allies, including some of the American airmen, even if the
Huns outnumbered them.

Back and forth over the German lines swept the glass-bottomed Spad, and
at a certain point Tom, who was looking down, uttered an exclamation. Of
course Jack could not hear, but he could feel the punch in the back his
chum administered a moment later.

Jack turned his head, and saw his chum eagerly pointing downward. A
moment later he motioned over his left shoulder, pointing backward, as
though they had just passed over something which would warrant a second
inspection.

Jack swung the machine about in a big circle, banking sharply, and then,
as he passed over the ground covered a little while before, he, too,
looked down, and with sharper glance than he had used at first.

What he saw was the ruins of a small French chateau. It had been under
heavy fire from the Allied guns, for it had sheltered a German machine
gun nest, and some accurate shooting on the part of the American gunners
had demolished it a day or so before.

But what attracted the attention of Tom and Jack was that whereas the
chateau before the bombardment had stood on a little hill without a
tree near it, now there was a miniature forest surrounding it. It was
as though trees and bushes had sprung up in the night. As soon as he
had seen this, Jack turned to Tom, nodded comprehendingly, and at once
started b