Suddenly Tom pulled the starting lever. There was a little clicking, followed by silence. Was the motor going to revolve? It answered the next moment with a whizz and a roar. "Here we go!" cried the young inventor, as the big machine shot forward on her flight. "Now let them stop us!" Forward she went until Ned, knowing by the speed that she had momentum enough, tilted the elevation rudder, and up she shot, while behind, on the ground, wildly running to and fro, and firing their rifles, were the two amazed guards. CHAPTER XXI THE RESCUE "Have we--have we time to get a drink?" gasped Ned, when the aeroplane, now on a level keel, had been shooting forward about three minutes. Already it was beyond the reach of the rifles. "Yes, but take only a little," cautioned Tom. "Oh! it doesn't seem possible that we are free!" He switched on a few interior lights, and by their glow the faint and starving platinum-seekers found water and food. Their craft had, apparently, not been touched in their absence, and the machinery ran well. Cautiously they ate and drank, feeling their strength come back to them, and then they removed the traces of their terrible imprisonment, and set about in ease and comfort, talking of what they had suffered. Onward sped the aeroplane, onward through the night, and then Tom, having set the automatic steering gear, all fell into heavy slumbers that lasted until far into the next day. When the young inventor awoke he looked below and could see nothing--nothing but a sea of mist. "What's this?" he cried. "Are we above the clouds, or in a fog over some inland sea?" He was quite worried, until Ivan Petrofsky informed him that they were in the midst of a dense fog, which was common over that part of Siberia. "But where are we?" asked Ned. "About over the province of Irtutsk," was the answer. "We are heading north," he went on, as he looked at the compass, "and I think about right to land somewhere near where my brother is confined in the sulphur mine." "That's so; we've got to drop," said Tom. "I must get the gas pipe repaired. I wish we could see over what soft of a place we were so as to know whether it would be safe to land. I wish the mist would clear away." It did, about noon, and they noted that they were over a desolate stretch of country, in which it would be safe to make a landing. Bringing the aeroplane down on as smooth a spot as he could pick out, Tom and Ned were soon at work clearing out the clogged pipe of the gas generator. They had to take it out in the open air, as the fumes were unpleasant, and it was while working over it that they saw a shadow thrown on the ground in front of them. Startled they looked up, to see a burly Russian staring at them.