“What is it now?” demanded Hal.

Chester did not reply immediately.  He appeared to be thinking deeply.

“Have you a knife?” he asked at length.

Hal produced one, and, taking it from his friend’s hand, Chester stepped to the back of the tent.  Quickly he opened the blade, and made a neat incision in the canvas, finally cutting out a little square.  Then he put his eye to the hole and peered out.

There was no one in sight.  The guard could be heard pacing to and fro in front of the tent, but apparently there was no guard at the rear.

Chester left his peep-hole and returned to Hal’s side.

“If we can get two of these bicycles out here,” he whispered, “we may be able to get away by a quick dash.  Are you willing to take a chance?”

“Sure,” agreed Hal.  “Anything is better than sitting here and waiting for I know not what.  But do you think we can make it?”

“Well, we can at least try.  There doesn’t seem to be a guard in the rear.  I am going to cut a big slit in the back.  Then we’ll slip the bicycles through it, mount and make a dash.”

“Good!” said Hal.

Quietly Chester slit the canvas in the rear of the tent, making a hole large enough for a man to step through.  Quietly the boys each selected a bicycle and pushed it cautiously through the opening.

Once on the outside they drew a breath of relief.

“We’ll have to depend on our luck now,” whispered Chester.  “Come on!”

The lads leaped into the saddles, and a moment later were speeding through the heart of the German camp.

In the very boldness of their scheme lay a certain degree of safety, for the sentinels on guard certainly did not look for two youths of the allied armies to be riding through their midst.

They were not even challenged as they sped through the camp, turning this way and that, and they had passed beyond the last row of tents before a hubbub from the rear told them that their flight had been discovered.

“We must be careful,” cried Hal, as he rode his wheel close beside Chester.  “There is still the outpost to pass.”

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.