"If we can figure out a way to do so safely, so it doesn't want to disintegrate all at once, I think we've really got a fuel--a super fuel. But we'll have to go at it mighty slow and easy. That stuff could blow us higher than up, if used wrongly." "Yes, I know. But after our scientists first liberated atomic energy for their bombs, many people said they couldn't control a hydrogen bomb, but they did. And later the thorium bomb. And then they got our activated copper. So I'm betting they can figure this out." Both fell silent, although there were a dozen eager questions the boy wanted so much to ask. But he did not interrupt his father's line of thought, even though long, long minutes dragged away while the elder still pondered the problem. At last, after more than a quarter of an hour, Tad Carver stirred and looked up. "This is going to take a long time to figure out," he said slowly. "I'm not too much on atomics, myself, and neither are you. Now you run along and do whatever else you have to do. It's a cinch we won't be able to try this stuff right away--if we try it at all." The disappointment on Jon's face was plain, but he restrained any protests, knowing his father was right, and not wishing to call down on himself another verbal chastisement like that recent one. "What about the rest of the stuff?" he asked instead. "Shall I get the box out of the cache and weld it onto the hull, as we thought we might do?" "I don't see why not. We want to take it back to Terra with us, whether we figure out how to use it, or decide the job's too big for us and turn it over to the scientists there to handle." "Right." Jon went over to the controls of the handling arms in the lock. Watching in the special visiplate, he opened the outer lockdoor, extended the "hands" and guided them down into the cache, after using them to lift the lid off the larger pit-box. Carefully he manipulated them to grasp the inner box by its lower end-edges, and experimentally lift it an inch or so. Finding that it balanced, he slowly made the servo-mechanism lift the heavy container from its ages old resting place and up onto the "top" surface of the ship, near the stern. Making sure it was securely held there, he put on his suit, gathered up his welding outfit, and went outside and climbed onto the hull. Going to where the box rested, he began the task of welding its bottom back-edge onto the metal hull. Then he released the grip of the handlers and, leaving them dangling in the air, welded the other three bottom edges. Finished, he turned off his torch, rose to his feet and started back. But after a step or two he stopped and thought. "Pop," he said into his suit-radio, "do you hear me?" "Yes, Jon," the answer came back at once into his earphones. "What is it?" "I was just wondering if it wouldn't be a good idea to spot-weld a few places along the edges of the cover, too, so there'd be less chances of its coming open. It'd be easy to open it later."