"It is all my fault," said Twiffle despondently. "I must have exposed the gravity plates too much when I adjusted them. I was so afraid the plane would fall. When the Airmobile passed into the area of gravity it shot _upward_. Now it is lost to us forever." Twiffle looked as if he were about to weep. "Cheer up, Twiffle," said the Shaggy Man. "Maybe we can get the Airmobile back." Shaggy turned to the Lord High Mayor and asked: "Since we can walk on air as well as you, couldn't we just walk up there and climb into the Airmobile?" "You could, if you wanted to stop breathing," said the Lord High Mayor cheerfully. "Why do you say that?" asked the Shaggy Man. "Because," exclaimed the Lord High Mayor, "we have discovered that the higher up you go, the thinner the air becomes. At the altitude now attained by your craft, the air would be so thin that it would be unbreathable." "Anyway," said Twink with a sigh, "the Airmobile isn't there any more." They all stared upward. The girl was right. The speck that had been the Airmobile had vanished completely. "Wonder where it went?" said Twink. The Lord High Mayor explained pompously. "Apparently your craft attained so great a speed that it shot off into space, beyond the power of gravity. From now on there's no telling where it will go." "And astronomers will report that folks from earth are about to visit another world, I suppose," grinned the Shaggy Man. "Too bad old Conjo isn't in it," grumbled Twiffle. "The question is," said Tom, "what do we do now?" "Right," agreed the Shaggy Man, as he turned to the Lord High Mayor and asked: "Sir, can you tell us how we can leave Hightown and proceed on our journey?" "You wish to leave Hightown? Where could you possibly wish to go?" inquired the Lord High Mayor. "Well, eventually we hope to reach the Emerald City in the Land of Oz," replied the Shaggy Man, "so we're heading for the Deadly Desert surrounding the Land of Oz. Then we'll have to figure out some way to cross the desert." The Lord High Mayor stared at Shaggy in horror. "The Deadly Desert!" he exclaimed. "Do you mean to stand here in the sky and tell me you actually wish to go near that terrible, burning, dry waste of shifting, deadly sands, when you can stay here and enjoy the delightful perfection of the aerial climate of Hightown?" "No," began the Shaggy Man patiently, "we don't like the Desert any more than you do, but in order to get to Oz we must cross the Desert. I assure you the Land of Oz has a climate just as delightful as that of Hightown." "That is impossible!" declared the Lord High Mayor indignantly. "Hightown has the only perfect climate in the world, and now that you are here, you might as well stay and enjoy it." "Wonder if he ever heard of California?" murmured Tom to Twink.