it
as it used to have. Anyhow it was leaking like a sieve, and I had to
head for our lines."

"Tough luck!" consoled Tom. Jack did not add that he had, as soon as he
landed, got into another machine, and was about to go back and join his
comrades when they returned, having practically won the battle above the
clouds.

Congratulations were extended to the members of the squadron, who
accepted their honors modestly enough, as was characteristic of them.

Then, after Tom's wound had been dressed, and he and Jack were talking
over the events of the day, there came a communication from the
commander of the air division in that sector. It was an order calling on
certain men to report at once for special duty. A picked squadron was to
be detailed for a hazardous enterprise, it was said.

"And our names are there!" cried Jack. "Tom, old man, we're going!"

"But where is it?" asked another American flier named Boughton. "What's
the game?"

Knowing the secret would be safe with him Tom said:

"We're going to pot the big German cannon that's bombarding Paris!"

CHAPTER XVI

MISSING

News of the shelling of Paris by the long-range gun had, of course, been
received at the aerodrome, though there had not, as yet, many details
come in. Tom and Jack, as the latest arrivals from the big city, were
called upon to tell all they knew, and they related their experiences in
the raids, and also told about the various theories of the big gun.

"But how are we going to find it?" asked. Boughton. "It's easy enough,
of course, for our squadron to go out with a lot of bombs. But where are
we going to drop 'em?"

"Oh, we're to go to Paris for further instructions before starting on
the quest," said Tom, who had made some inquiries about the orders
concerning the picked squadron.

"And they may have discovered its location by this time," added Jack.
"We know about where it is--somewhere in the sector between Hamegicourt
and Conde. The rest ought to be easy."

"Not so easy as it sounds, my friends," put in a French flier. "I know
that region. It is a big one; and the Germans no doubt have their gun
well camouflaged. It will not be easy."

"But we'll get it!" asserted Tom.

"Naturally," said the Frenchman, as if that was all there was to it.

Tom's wound was painful, but not dangerous, though it would keep him on
the ground for a day or two. Though, as a matter of fact, none of the
members of the picked squadron was allow