ad
uncovered.

"I guess they decided it was better to risk being surprised than to give
themselves away," he said to himself. "Otherwise they'd have been pretty
sure to leave an outpost of some sort here because this road looks like
just the place for troop movements. It looks more and more as if they
had really managed to make a secret of this column."

It did not take him long to find the windmill of which Henri had told
him. The place was deserted; there was no one to oppose his entry. And,
when he reached the top, he found that there was an excellent view of
the country for several miles, a much better one than they had had from
their shelter on the hillside above the Germans.

He could see the woods into which the invading troops had disappeared,
looking dark and mysterious in the deepening twilight. There was no sign
of life about them; no smoke rose above the treetops. And no Germans
were beyond them. Then his guess had been right, he decided. They had
made for those woods to obtain shelter, and they relied upon the fact
that the allies did not know of their presence. It was a daring move; it
might well have been successful, save for the accident of the two boys
who had observed it. Indeed, even now there was a chance, and something
more than a chance, that the German object, whatever it was, might be
attained. Frank and Henri were a long way yet from having reached the
British headquarters. Unknown dangers and obstacles lay between them and
their destination.

"With the German attack developing so quickly as this, we don't know
where we may not run into them," mused Frank, as he descended from the
windmill and mounted his wheel, preparing to start back to join Henri.
"They may be anywhere. I don't want to see them win, but they certainly
are wonderfully good fighters. They have good leaders, too."

When he reached Henri he found that his French comrade was lighting the
lamp of his bicycle. With a laugh he blew out the flame.

"But it's dark and we'll be arrested if we ride without a light," said
Henri, protestingly.

"That law was made for peace, not for war," said Frank. "When we know as
little about where the Germans are as we do, I'm not going to take any
chances. We'll ride with lights out, thank you. Come on!"

As they rode along in the growing dusk, close together, Frank told what
he had seen.

"That was a good guess, then," said Henri. "But, Frank, how can they
know so well what to do? You woul