“I’d rather not have had those years of sorrow, all the same,” said Sir John softly. “I’d rather have destroyed the Argenta with my own hands, and never built her up again, than you should both have left me for those long years,” and the old man turned away with a sigh. “Now about our air supply,” he went on, recovering himself. “As the used up air sinks to the ground, it is attracted into pipes, and by the aid of tiny electric fans is driven to a large cylinder. There it undergoes a kind of filtering process. The purer portions go into circulation again, while the carbonic acid gas is taken down pipes which run along the whole side of the ship to an outlet where it can escape into space. To guard against the extrance of any unknown noxious gases, this pipe has a trap in every foot, which closes mechanically as the gas passes through. The mechanism of these traps makes it impossible for any foreign air to enter. No matter where we are, or through what poisonous air we may pass, we are protected from its entrance by this device; while it is impossible for the ship to collapse while it is protected by its envelope of ether.” “Then you could live as long as your provisions lasted on the Argenta?” asked Desmond. “You are not dependent on the outer world for anything?” “We are dependent only on ourselves,” replied Sir John. “Why, it’s like a fairy tale,” said Mavis. “Tea,” said a voice from behind them. “Tea, Mrs. Forsyth.” It was Hector. Masters had unobtrusively left while they were all talking, and Hector had turned cook. “Tea is served in the Bows,” said Hector again. Masters had drawn back the shutters, and once again the little room was flooded with sunshine. The telephone bell tinkled. “Well, Masters?” “We are passing over Whitby, sir. Do you wish to cut across country direct for Dalmyrnie, or will you go right round by the coast?” “Time is getting on. I think we had better make straight for home.” “Very good, sir.” “It’s been a wonderful success,” said Alan. “More wonderful than I could have dreamed possible.” Sir John beamed at the praise. “But, Uncle John, leave your atmospheric experiments until I come back from Kalvar. I’d love to accompany you on your adventures.” “Would you really?” “Nothing would give me greater pleasure.” “Look,” said Mavis presently. “We are over Loch Tay. How beautiful it looks from here. Why there is still a suspicion of snow on Ben Lawers.” “We are very near home, now,” said Desmond, looking at her fondly. Within a very few minutes the great vessel tilted ever so slightly, and then with a graceful movement, slanted her nose to earth. There was only the faintest suspicion of a jolt as she touched the ground, and then ran smoothly along the field, coming to a standstill at almost the very spot she had left a few hours before. The trial was over! The machine had proved her worth. Science had won yet another brilliant victory.