of the small aircraft, since it allowed them to be
together.

The few lights of the aviation field near Bar-le-Duc had faded almost
entirely out of sight by the time Tom turned to the north and headed for
Verdun. True, he might have pointed the nose of the airplane directly
east, and saved considerable distance, but there were good reasons for
not doing this.

To cross the German lines further south would surely convince the
Teutons that the aviators were heading for the vicinity of Metz, which
was just what Tom did not wish to have happen. Then again, his chart
covered only the direct line between Verdun and the fortified city of
Lorraine that forty-odd years back had been French territory, before the
Germans seized it as spoils after the war that made France a republic
for the third time.

CHAPTER XV

THE MOONLIGHT FLIGHT

The time for talking had passed. With the motor working noisily, and the
twin propellers churning the air, they could hardly have heard the
discharge of one of the 'Big Berthas', as the Allies were wont to call
the monster Krupp guns, and so called them because a woman whose maiden
name had been Bertha Krupp, owned a big interest in the works where they
were manufactured.

All was dark around and below them. Above the stars shone, and gave a
small amount of cold, cheery light. Tom had made a study of the heavens,
and was able to steer by means of the stars. The aviator is often as
much dependent on compass and heavenly bodies to shape his course as the
sailor hundreds of miles away from land.

Tom was in no especial hurry. He had carefully thought out his plans,
and meant to pass over Verdun at just a certain time. Then would come
the two lines of hostile trenches, and the ordeal of searchlights and
shrapnel. Once that was done with, they had really little further to
fear.

The minutes slipped away. Under ordinary conditions they were accustomed
to making that thirty miles in just about half that number of minutes,
thanks to the ability of the speedy Nieuports to cover distance. It
would be twice that now before they would find themselves at the front.

Already they could see various signs to tell them they were drawing
near. Rockets used as signals of various kinds ascended at intervals,
and burst. Others of the star variety, and which discharged glowing
white electric balls that lighted the earth below, could also be seen.
One side or the other apparently had some reason for d