"Fly about in the Falcon, in ever-widening circles, starting as near the centre of that area as possible," replied Tom. "And as soon as I run into a steady hurricane I'll know that I'm at the place of the big winds, and I'll get out my glider, for I'll be pretty sure to be near the place." "Bless my gas meter!" cried Mr. Damon. "That's the talk!" Tom put his plan into operation at once, by heading the nose of his craft for the desolate region mapped out by the Russian brothers. The days that followed were filled with weary searching. It was like the time when they had sought for the plain of the great ruined Temple in Mexico, that they might locate the underground city of gold. Only in this case they had no such landmark as a great Aztec ruin to guide them. What they were seeking for was something unseen, but which could be felt--a mysterious wind--a wind that might be encountered any time, and which might send the Falcon to the earth a wreck. The Russian brothers, staggering about in the storm, had seen the mine under different conditions from what it would be viewed now. Then it was winter in Siberia. Now it was summer, though it was not very warm. On and on sailed the Falcon. The weather could not have been better, but for once Tom wanted bad weather. He wanted a blow--the harder the better--and all eyes anxiously watched the anemometer, or wind gage. But ever it revolved lazily about in the gentle breeze. "Oh, for a hurricane!" cried Tom. He got his wish sooner than he anticipated. It was about two days after this, when they were going about in a great circle, about two hundred miles from the imaginary centre of the district in which the mine lay, that, as Mr. Damon was getting dinner a dish he was carrying to the table was suddenly whisked out of his hand. "I say, what's the matter?" he cried. "Bless my--" But he had no time to say more. The airship fairly stood on end, and then, turning completely about, was rapidly driven in the opposite direction, though her propellers were working rapidly. "What's up?" yelled Ned. "We are capsizing!" shouted Ivan Petrofsky, and indeed it seemed so, for the airship was being forced over. "I guess we've struck what we want!" cried Tom. "We're in a hurricane all right! This is the place of the big wind! Now for my air glider, if I can get the airship to earth without being wrecked! Ned, lend a hand! We've got our work cut out for us now!" CHAPTER XXIII THE LOST MINE For several moments it seemed as if disaster would overtake the little band of platinum-hunters. In spite of all that Tom and Ned could do, the Falcon was whipped about like a feather in the wind. Sometimes she was pointing her nose to the clouds, and again earthward. Again she would be whirling about in the grip of the hurricane, like some fantastic dancer, and again she would roll dangerously. Had she turned turtle it probably would have been the last of her and of all on board.