rman cannon. Would it succeed?

That was a question every man of the Allies asked.

Shortly after the arrival of the picked squadron at the camp, which, in
honor of Tom and Jack had been named "Lincoln," word came in over the
wireless that the big gun had again fired on Paris.

"It's funny we didn't hear any report of it," said Jack.

"There have been reports enough," Tom remarked. "I've heard the booming
of distant guns ever since we got near this place. Any one of them may
have been the monster, or they may have been firing other guns to hide
the sound of this cannon. Then, too, it may not make as much noise as we
think it ought to. The Germans may have found a new kind of powder, or
even some propelling gas, that makes no extraordinary report. In that
case we couldn't locate the gun by the sound."

"Maybe you're right," agreed Jack. "Anyhow they're firing, that much is
proved; and it's somewhere over there," and he motioned toward the
German lines.

Much as the airmen desired to start at once in their search for the
monster cannon, it was deemed wise to have first a consultation and a
general understanding of what means should be employed.

Then, too, all the aircraft were new, having been shipped to Camp
Lincoln and there assembled, and it was desired to test them before
taking the dangerous flights over the German lines. So the airmen would
have to spend some time--perhaps half a week--in preliminary work.

Meanwhile the great cannon would keep up its deadly, though, from a
military standpoint, useless work.

And so began the preparation, if such it might be called. Every one,
from the most daring "ace" to the humblest kitchen helper in the camp,
was anxious for the day when it could be said that the gun was out of
commission, or guns, if, as was likely, there was more than one. But the
men in command knew the value of thoroughness. There must be no failure
through lack of making proper plans.

But at last everything was in readiness. The planes had been tested,
keyed up, and the motors run until every part of them was humming like a
top. Each man felt confidence, not only in himself but in his craft, and
that meant much. There were several types for the fliers to use,
single-seaters, the big bombing craft, those equipped for slow flying
and from which photographs were to be taken, as well as others. The
taking of photographs was expected to help in revealing the position of
the hidden gun.

The big It