be easily and quickly mounted and dismounted, and at the close of
each day's flight the guns are carefully inspected and cleaned ready
for the morrow.

"Locate the machine gun battery if you can," was the parting request
to Tom and Jack as they prepared to ascend. "Send back word of the
location as nearly as you can to our batteries, and the men there
will see to the rest."

"We will!" cried the Americans.

Locating a machine gun nest is not as easy as picking out a hostile
battery of heavier guns, for the former, being smaller, are more
easily concealed.

But Tom and Jack would, of course, do their best to help out their
friends, the French. Over toward the German lines they flew, and
began to scan with eager eyes the ground below them. They could not
fly at a very great height, as they needed to be low down in order
to see, and in this position they were a mark for the anti-aircraft
guns of the Huns.

They had no sooner got over the enemy trenches, and were peering
about for the possible location of the machine gun emplacement, when
they were greeted with bursts of fire. But by skillfully dodging
they escaped being hit themselves, though their machines were
struck. The two chums were separated by about a mile, for they
wanted to cover as much ground as possible.

At last, to his great delight, Tom saw a burst of smoke from a