etrayed by spies or traitors."

"We'd better say nothing about it," Tom concluded. "I'm going to run
over the entire machine on my own account."

"And I'll do the same, Tom; for a pilot can't be too sure of his mount,
especially when there's such meanness afoot."

They accordingly busied themselves after their individual fashion. Every
brace and stay was looked over carefully and tested as only pilots know
how. Long experience, and many accidents have taught them where the weak
spots lie, and they understand how to guard against the giving way at
these points.

So the minutes passed. Other pilots had already ascended to await the
assembling of the picked squadron at some given altitude. Every minute
or two could be heard the rush of some unit starting forth. There were
few of the accompaniments of an ordinary ascent, for all loud cries had
been banned.

"All ready!" came the welcome words at last.

The last strut had been carefully gone over, and now everything was
pronounced in perfect condition. At the same time, after such a discovery
had been made, it was only natural for the boys to feel a queer tug in
the region of their hearts as they climbed to their seats, and with hands
that quivered a little proceeded to make fast the safety belts.

"There goes another bomber, which makes four--the full number you spoke
of, Tom," remarked Jack. "I suppose we're holding up the procession more
or less, worse luck, when usually we can be found in the lead."

"The commander must know about our mishap," replied Tom, "and isn't
apt to blame us for any little delay. The night's still young, and we
can reach our destination in half an hour, with time to spare. So
cheer up, old comrade; everything's lovely and the goose hangs high.
Now we're off!"

With that he gave the word, and paid attention to his motor, which
started a merry hum. The propellers commenced to spin, and down the
slight slope they ran with constantly increasing speed. All around them
could be heard the refrain of planes in action; from above came similar
sounds, and Jack, looking up, discovered dim scurrying forms of
mysterious shape that flitted across the star-decked sky like giant bats.

Now they, too, were rising swiftly in spirals. Both kept a keen watch,
for it was at this time they stood the greatest chance of taking part in
an unfortunate collision that might result in a fatal disaster.

But every pilot was on edge, and careful to avoid any such b