march in a long line from the
mine. Then for the rescue."

It was tedious waiting that day, but it had to be done, and to Tom, who
was anxious to effect the rescue, and proceed to the place of the winds
to try his air glider, it seemed as if dusk would never come as they
remained in concealment.

But night finally approached and then the great airship went silently
aloft, ready to hover over the prison ground. Fortunately there was
little wind; and she could be used as a balloon, thus avoiding the
noise of the motor.

"The next thing I do, when I get home," remarked Tom, as they drifted
along. "Will be to make a silent airship. I think they would be very
useful."

With Mr. Borious in the pilot house, to point out the way, Tom steered
through the fast-gathering darkness. The Russian had soon become used
to the airship, and was not at all afraid.

"Can you go just where you want to, as a balloon?" asked the new guide.

"No, but almost," replied Tom. "At the last moment I've got to take a
chance and start the motor to send us just where we want to go. That's
why I think a silent airship would be a great thing. You could get up
on the enemy before he knew it."

"There are the prison barracks," said the guide a little later, his
talk being translated by Mr. Petrofsky. Below and a little ahead of
them could been seen a cluster of lights.

"Yes, that looks like a line of prisoners," remarked Ned, who was
peering through a pair of night glasses.

"Where?" asked Tom eagerly, and they were pointed out to him. He took
an observation, and exclaimed:

"There they are, sure enough. Now if your brother is only among them,
Mr. Petrofsky, we'll soon have him on board."

"Heaven grant that he may be there!" said the exile in a low voice.

A moment later, the Falcon, meanwhile having been allowed to drift as
close as possible to the dimly-seen line of prisoners, Tom set in
motion the great motor, the propeller blades heating the air fiercely.

At the sound there was a shout on the ground below, but before the
excitement had time to spread, or before any of the guards could form a
notion of what was about to take place, Tom had sent his craft to earth
on a sharp slant, closer to the line of prisoners than he had dared to
hope.

Mr. Petrofsky sprang out on deck, and in a loud voice called in Russian:

"Peter! Peter! If you are there, come here! Come quickly! It is I, your
brother Ivan who speaks. I have come to save you-