"I'm going up a couple of hundred feet at least," answered Tom, "and higher if the gale-strata is there. I want to give it a good test while I'm at it." Ned looked down through a heavy plate of glass in the floor of the cabin, and could see Mr. Petrofsky and Eradicate looking up at them. "Bless my handkerchief!" cried Mr. Damon, when his attention had been called to this. "It's just like an airship." "Except that we haven't a bit of machinery on board," said Tom. "These weights do everything," and he shifted them forward on the sliding rods, with the effect that the air glider dipped down with a startling lurch. "We're falling!" cried Ned. "Not a bit of it," answered Tom. "I only showed you how it worked. By sliding 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.