're thinking of another expedition, Tom?"

"Oh, he'll want me to go when he hears about the exile."

"And I'm sure my folks will let me go. How about Mr. Damon?"

"I don't believe we can hold him back. It will make a nice party, just
you and I, and Mr. Damon and Mr. Petrofsky. That will leave room for
the other Russian--if we can rescue him," and with that Tom shut off
the engine and glided to earth.

It may well be imagined that Mr. Swift was surprised when his son told
him the latest news, but he did not offer any serious objection to the
young inventor going to Siberia.

"Only you must be careful," he said. "Those Russian officers are ugly
when it comes to trying to take away any of their prisoners. And this
air glider--I don't exactly know about that. It's a new machine, and
you want to be sure it works before you trust yourself to it."

"I will," promised Tom. "Say, I've got plenty of work ahead of me,--to
get my big airship in shape, and build the glider. You'll have to help
me, dad."

"I will, son. Now tell me more about this Mr. Petrofsky." Which Tom did.

The days that followed were indeed busy ones for Tom. The young
inventor made a model air glider that sailed fairly well, but he knew
it would have to work better to be successful, and he bent all his
energies in that direction. Meanwhile Mr. Damon had been told of the
prospective trip.

"Bless my bank book! Of course I'll go," he said. "But don't say
anything about it to my wife--that is, just yet. I'll bring her around
to it gradually. She has always wanted a diamond ring set in platinum,
and now I can get it for her. I know she'll let me go if I break it to
her gently."

It may be mentioned here that many valuable diamonds are now set in
platinum instead of gold.

"I want to keep busy," said Mr. Damon, so Tom set him, Ned and
Eradicate at the task of getting the big airship in shape for the trip.
This air craft has not figured in any of my previous stories, but as it
is so nearly like the one that was crushed in the caves of ice, I will
not give a description of it here. Those who care to may refer to the
book telling of Tom's trip to the caves of ice for a detailed account
of the craft.

Sufficient to say that this latest airship, named the Falcon, was the
largest Tom had ever built. It contained much room, many comforts, and
could sail for several thousand miles without descending, except in
case of accident. It was a combined dirigible bal