ng the weights back we go up."

He demonstrated this at once, sending his craft sliding up another hill
of air, until it reached an elevation of four hundred feet, as
evidenced by the barograph.

"I guess this is high enough," remarked Tom after a bit. "Now to see if
she'll stand still."

Slowly he moved the weights along, by means of the compound levers,
until the air glider was on an "even keel" so to speak. It was still
moving forward, with the wind now, for Tom had warped his wing tips.

"The thing to do," said the young inventor, "is to get it exactly
parallel with the wind-strata, so that the gale will blow through the
two sets of planes, just as the wind blows through a box kite. Only we
have no string to hold us from moving. We have to depend on the
equalization of friction on the surfaces of the wings. I wonder if I
can do it."

It was a delicate operation, and Tom had not had much experience in
that sort of thing, for his other airships and aeroplanes worked on an
entirely different principle. But he moved the weights along, inch by
inch, and flexed the tips, planes and rudders until finally Ned, who
was looking down through the floor window, cried out:

"We're stationary!"

"Good!" exclaimed Tom. "Then it's a success."

"And we can go to Siberia?" added Mr. Damon.

"Sure," assented the young inventor. "And if we have luck we'll rescue
Mr. Petrofsky's brother, and get a lot of platinum that will be more
valuable than gold."

It would not be true to say that the air glider was absolutely
stationary. There was a slight forward motion, due to the fact that it
was not yet perfected, and also because Tom was not expert enough in
handling it.

The friction on the plane surfaces was not equalized, and the gale
forced the craft along slightly. But, compared to the terrific power of
the wind, the air glider was practically at a standstill, and this was
remarkable when one considers the force of the hurricane that was
blowing above below and through it.

For actually that was what the hurricane was doing. It was as if an
immense box kite was suspended in the air, without a string to hold it
from moving, and as though a cabin was placed amidships to hold human
beings.

"This sure is great!" cried Ned. "Have you got her in control, Tom?"

"I think so. I'll try and see how she works."

By shifting the weights, changing the balance, and warping the wings,
the young inventor sent the craft higher up, made