traps
go? Right! I'm going to make a bonfire. It'll bring someone to help
those poor chaps. I don't want them to have to lie here all night unless
they have to."

He took the can which Frank had almost emptied and poured what gasoline
remained on the ground that had been protected from the rain by one wing
of the monoplane. Then he flung a match into the now highly inflammable
stubble, and a flame leaped up at once, lighting the monoplane and the
two wounded Germans. In a moment more he was in his place and the
monoplane was plunging along the ground. Then it took the air and rose
swiftly to a safe height. And then for the first time there was a
chance for explanations.

"By Jove, how did you come to think of flashing that message to me?"
cried Greene. "That was an idea! I almost gave it all away by answering
before I realized what you were telling me. What was that fire I saw?
Looked to me like the very place you said you were going to."

So Frank explained.

"Oh, splendid--my word, splendid!" cried Greene. "I fancy we'll find
they've started this way already. Hullo--yes, by Jove, there come some
of our fellows now! See, over there to the right? Aeroplanes--gone to
spot those Johnnies. They didn't wait for us to come back!"

He dropped to a bare hundred feet of elevation now and in a moment Frank
could see why. Below them a mass of cavalry was in motion.

"There they go!" cried Greene. "Your beacon gave them the line. The
general must have decided that was confirmation enough."

Now came a shouting from below, and Greene answered it by swooping down
to a landing in the field. An officer put his horse to the wall and rode
up beside them.

"Captain Greene, by any chance?" he called, peering at them.

"Yes, colonel," said Greene, saluting. "The Germans are in a clump of
woods on the Amiens road. In an angle of that road and the one from
LaFere, rather. I don't know the exact strength, but have reason to
believe about five thousand."

"There's no doubt about their being there, though?"

"None at all, sir. They shot a hole in my tank, and I had to wait to get
enough essence to come back. All mine leaked before I could make a
landing to plug the bullet hole. Did you start on the sight of that
burning house?"

"Yes. The staff couldn't see why a house should be burning unless there
were Germans about. Very well. Report back to headquarters, captain.
They're waiting for you."

"Very well, sir."

"I thought so