Gosh, he had the stuff, but was it safe to touch it off? He sat down and ran his fingers through his chestnut curls and studied his apparatus. Flame could not possibly backfire through solid water. Hadn’t he figured this thing out himself? So he applied a match to the soap bubbles and was rewarded by a delightful fusillade—like a machine gun about a thousand miles away and ten years off. “Not dead yet, dad.” “No, not yet,” smiled Chase Mahan. Chapter 2. Helium Three years passed, and Marvin was in the high school without having blown his eyes out. He was distinctly tamer now, though still afflicted with excess of leisure because his mathematics cost him so little. He always had time for sports, and the boy of fifteen was madly fond of dancing. That summer his father took him on a long prospecting trip in the wilds of Canada and watched him develop into young manhood. Every morning they had their swim together in the pellucid purity of some lake rarely seen by the eyes of white men. All day long they searched ravine and gully, moving slowly from east to west across the continental formation. Every night they lay by the camp-fire and talked about many things, sometimes about the future. It was agreed that Marvin should be a chemist, but Chase kept drilling it in that early specialization was bad. He had suffered from it all his life, and wanted his boy to go slow. Near the end of the trip the mining engineer slipped in crossing a slope of rock, and fell. When he arose, his right hand was so useless and painful that he suspected some bones had been broken. The first thing he did on reaching Chicago was to proceed to the hospital and have the swollen hand radiographed. One bone was found to be split, and the sufferer was led to another room that the hand might be immobilized. Thus left alone with the X-ray man, Marvin plied him with questions. He so fascinated the radiographer that presently he was rewarded with a mystery even greater than that of the subtle unseen light. He was taken into a dark closet and permitted to peer into a small instrument containing salts of radium. He saw a flight of stars, a sheaf of rays, a faint fierce sparkling! The heavy metallic radium atom was exploding! It was bombarding a small black screen with cannon flashes! Instantly the boy inquired why somebody did not capture the power of that explosion and set it to work. He was told that any such achievement was impossible. The show was not affected by heat or cold, and would continue for a thousand years or more till the radium was all used up. What were those flashes? How could he learn more about them? He must wait till he had enough physics to follow the writings of a man named Rutherford.