"Good!" exclaimed the man. "Now listen. I am an American, and I was captured by the Germans, through spy work, some time ago, in Paris. I was brought here, and they have been trying to force me to disclose the secret of some of my inventions.
"I refused, and was sentenced to be shot to-morrow. But to-night you fortunately raided this place. My prison was one of the places to be blown up, and I managed to escape, without being hurt much. I heard that they had captured the crew of one of the airships, and I came to see if I could help. They don't know yet that I'm free, and I have two hand grenades.
"Now listen carefully. I'll throw the grenades at the front gate. By shattering that it may be possible for you to get out. The two sentries, will have to take the chances of war. If you get out can you get away in your airship?"
"Yes, and we can take you with us—Dad!" exclaimed Tom in a tense whisper.
"Who speaks?" hoarsely asked the man in the shadow of the stockade.
"It is I—your son—Tom Raymond! Oh, thank heaven I have found you at last!" exclaimed Tom, and he tried to stretch his hand through the barbed wire, but it was too close.
"Is it really you, Tom, my boy?" asked Mr. Raymond in a broken voice, full of wonder.
"Yes! And to think I should find you here, of all places!" whispered Tom. "I won't stop now to ask how it happened. Can you throw those grenades at the gate?"
"I can, and will! Tell your friends to run back to the far end of the stockade to avoid being hurt. I can crouch down behind some of the ruined walls."
Tom and Jack quickly communicated the good news to their friends, that a rescue was about to be attempted. It was a desperate chance, but they were in the mood for such.