between the mingled French, British and French forces and the Huns,
and honors were on the side of the former. There had been one or
two combats in the air, in which Tom and Jack had taken part, when
one day word came from an observation balloon on the American side
that a flock of German aircraft was on the way from a camp located a
few miles within the Boche lines.

There was a harried consultation of the officers, and then orders
were given for a half score of the Allied machines to get ready.
Two veteran French aces were to be in command, with Tom and Jack as
helpers, and some of the American aviators were to go into the
battle of the air for the first time.

"The Huns are evidently going to try to bomb some of our ammunition
dumps behind our lines,"' said one officer, speaking to Tom. "It's
up to you boys to drive 'em back."

"We'll try, sir," was the answer. "We owe the Huns something we
haven't been able to pay off as yet."

Tom referred to the loss of Harry Leroy. So far no word had been
received from him, either directly or through the German aviators,
as to whether he was dead or a prisoner. Letters had passed between
Bessie and Nellie and Jack and Tom, and the sister of the missing
youth begged for news.

But there was none to give her.

"Unless we get some to-day," observed Tom as he and his chum hurried
toward the hangars where their machines were being made ready for