"I've had an idea," he said. "How's your stock of spare parts in the garage?" "Good. I always was a fool about stocking up on things I could never sell." "Any blocks?" "About a dozen, why?" "Could you make a brand-new engine out of spare parts?" The mechanic considered, then nodded. "I think I could put together a Ford or Chevy engine. What good would that do? It would run down in a few days, just like all the rest." "Do you think it would, if you put it in a sealed room, and supplied only filtered air to it?" Art's eyes lighted. "Why the dickens didn't we think of that before? If we could keep the stardust from getting to the engine, there's no reason at all why it shouldn't run as long as we wanted it to, is there?" "If a generator could be assembled in the same way, we could stir up a little power on an experimental basis, enough to charge our radio batteries. I wonder how much power could be generated in the whole country by such means?" "I know we could get a couple of dozen engines going here in Mayfield, at least!" said Art. "Why don't you get started right away? Get some of the club guys to help. If that filter idea works there may be a lot of things we can do." Art started for the door. "Sheer genius," he said admiringly. "That's sheer genius, Boy!" Ken smiled to himself. He wondered why they hadn't tried that when they first had the hunch that comet dust could be responsible. Maybe they could have saved some of the cars if they had rigged more efficient filters on the air intakes. His thoughts went back to the attack. He was still thinking about it when his father and Sheriff Johnson returned. "We took your word, Son," the Sheriff said, chagrined. "We got a warrant and searched the Tucker and Allen premises from top to bottom. We went out to Tucker's farm and went through the barns and the house. They've got a 2-day supply of rations just like everybody else. "They screamed their heads off and threatened suit for slander and false arrest and everything else in the books." "I'll get hold of Jed Tucker when I get out of here," said Ken. "He'll talk when I get through with him!" "Don't get yourself in a worse jam than you've stirred up already. Unless you can prove what you say, you'll just have to forget it and keep quiet." Ken smiled suddenly. "It just occurred to me--when a banker wants to keep something safe, where does he put it?" "In the bank, of course," said the Sheriff. "Wait a minute, you don't think...." "Why not? The bank isn't doing business any more. Tucker is the only one, probably, who has any excuse to go down there. As long as things are the way they are, nobody else is going to get inside the vault--or even inside the building." Professor Maddox and the Sheriff looked at each other. "It's a logical idea," said Ken's father. "It's as crazy as the rest of it! We've made fools of ourselves already so we might as well finish the job!" * * * * *