But they did not diminish their speed. Rather, if anything, they
pedaled faster; and then the outpost came into sight--a long line of
men, almost in front of them. Some were pacing to and fro, while others
sat upon the ground.

The riders were upon them before they knew it, and two flying bicycles
sped between the German troopers. A cry of "halt!" went unheeded, and the
Germans, quickly bringing their rifles to their shoulders, sent a volley
after the lads.

But neither was hit. In the darkness the Germans were unable to aim
carefully. The boys heard the hum of bullets around them, but they did
not falter. There was no second volley, for the lads had disappeared in
the darkness, and the Germans were not minded to spend their ammunition
foolishly.

The first streak of dawn appeared in the sky, and still the boys rode on
swiftly. But at length Hal slowed down and Chester followed suit.

"I'm tired out," said Hal, as he jumped from his bicycle.

"And so am I," replied Chester, as he, too, jumped to the ground to
stretch his legs.

Suddenly from the distance in which they had come came a faint
"chug-chug."

Chester pricked up his ears.

"What's that?" he demanded anxiously.