in the distance and to the
east, the telltale music of Teuton propellers beating the air in a rush
for home ports.

A pursuit was organized, and several planes followed the retreating
invaders over the entire distance to the front; but it was of no avail.
The enemy planes had had too good a start, and were being pushed for all
they were worth to get beyond the danger zone.

There had been several accidents at the Bar-le-Duc field, but none of
them fatal. This was not at all surprising, considering the haste shown
by the pilots to mount and engage the foemen.

Too, several of the planes besides Jack's had been damaged, a
circumstance which brought about disaster before the aviator was able to
leave the ground.

As the fliers came back one after another, filled with indignation and
disappointed hopes, Jack stalked about, with his black face, yet laughed
to see what comical pictures most of his fellow aviators made.

By degrees most of them began to realize that the joke was on them, and
joined in greeting with noisy shouts each fresh arrival from above. The
damage had not been so very serious after all, since most of the Teuton
bombs had either failed to explode when aimed true, or else only dug
enormous craters in the ground where it did not matter, sometimes even a
quarter of a mile away from the hangars. Jack's machine, it was found,
was the only one badly damaged.

From that time there was one subject on which American and French pilots
were agreed. They must certainly repay their enemy rivals for this
visitation. The honors could not continue to be all on one side.

So from that hour every Allied pilot who went far back of the German
lines used his glasses diligently, in the endeavor to locate the secret
aviation field of the Boche. This would naturally be camouflaged in the
customary fashion, at which the Teutons had become almost as proficient
as the French; but trust an airman to spy out the lodging place of his
kind.

Step by step they learned which direction the enemy planes took in
coming to the front, and retiring when through for the day. Thus in good
time the hiding place was found. Great was the delight of the whole
Lafayette Escadrille when this confidential news was passed about. And,
later on, a party of Allied aviators paid a night visit to the German
camp, and dropped several tons of high explosives from bombing planes,
that were heavily guarded by the fighting Nieuports.

They had reason to