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."