At the Director's nod, he began outlining the facts to them. Some already knew of what was being done here, but all were listening as if the Director himself were speaking. He could only give the barest facts. He'd been experimenting with a means of controlling fission for some power application, working on the problem of getting hydrogen to fission at temperatures below the millions of degrees where it normally began, and in tiny amounts. And by sheer accident, he had stumbled on a process where nitrogen fissioned, instead--two atoms of nitrogen combining into one, straining the nucleus that now held fourteen protons and fourteen neutrons, distorting it until some of the binding force of the nucleus released energy, and it broke up into simpler atoms again--as if both fission and fusion were going on. It had not been successful, from a commercial angle, but it had produced an unexpected result. The mice which had been kept to test out danger of radiation had not been killed--but they had been sterile, as events proved, from then on. The release of radiation was not quite normal gamma rays; it was subtler than that--some queerly polarized radiation that struck at the fertility of animals and ended it. "But you were not sterilized," Ki Fong interrupted him. "I was lucky--I had been using a shield that was heavy enough to turn aside the radiation--the four-foot walls of the oven where the experiment was conducted. It only leaked out through the panel we later found had a crack in it--but that was toward the mice." Three years had been spent in testing it on mice, before the reports had found Petrecci, and brought him to the little laboratory of Johann Volcek. By then, Volcek had developed a complete control of the process, and had learned to fuse and fission oxygen as well as nitrogen, but without the production of sterilizing radiation this time. After that, there had been no more mice. Volcek shuddered, trying to conceal it, as he remembered the prisoners who had stood before the portal of the oven, and gone away, sterile. And there had been tests in the big, deserted wastes near the Gobi, where balls of fire had leaped from his tiny little devices, and cracked themselves into flaming energy that grew and spread before vanishing. More sterility had followed. "It requires very little apparatus," Volcek said, finally. He pulled a small tube from a drawer near the wall, and held it out to them. "This is the source. A small battery, these coils, tubes, this little crucible--nothing more. Once we knew why it started the fusion, it was easy to simplify." And it was simple. A man could carry one of the devices with him in a small bag, and it was meaningless in appearance. It could be built into a radio, as if it were part of the tuning device. It could slip past customs, harmless in its looks, and be spread wherever wanted. And now.... * * * * *