night."

Jack tried to keep calm, but it was indeed difficult, and his voice
faltered more or less as he hurriedly went on to say:

"Have you already made your selection?"

"Yes," the other assured him in his tantalizing way. "I wanted to know
whether the captain approved of my choice; which I am glad to say turned
out to be the case."

Jack gulped something down, and then blurted out:

"Did you mention my name at all, Tom?"

"Yours was the only one I had in mind; and Jack, rest easy, you're going
along with me to-night to glimpse the lights of Metz!"

CHAPTER XIV

OFF ON A DARING MISSION

The two air service boys fell to talking earnestly concerning what they
should take with them, and how to study a map which their captain had
promised to put in Tom's hands immediately.

This was not of the ordinary kind, but so definitely marked for just
such an emergency that even a novice could probably find his way to
Metz, granting that he possessed the necessary qualifications of an air
pilot.

Presently a messenger came with a package for Tom. This proved to be the
chart from the commander of the air squadron. Tom was to make as good a
copy as was in his power, for the original was too valuable to risk
losing.

Jack understood that there were several reasons for having Tom do this.
In the first place his work on the chart would familiarize the young
aviator with its every detail, and fix things firmly in his mind. Then
again, if they were lost, and never returned, the priceless chart for
night voyaging over the enemy's lines would be at least safe.

Daring men had gone forth on similar desperate errands before then, and
had never been heard from again. It is the fortune of war. Those who
indulge in enterprises that border on the sensational must always expect
to sup with deadly peril.

When the evening meal was announced the two chums were already deep in
the work. Of course not a whisper of their intended mission was breathed
at the table. No one dreamed of their contemplated trip. The customary
chatter and good-natured badinage flowed during the whole supper-time.
While some of the American aviators had received wounds in recent
engagements there had been no chair vacant for some little time now; and
hence no gloom rested on the escadrille. From the table the boys again
went to their room.

"How far is Metz from Verdun?" asked Jack, as they labored to complete
their preparations for departure.

"