Silence, like the brooding hush of impending doom, fell over the chamber as the significance of his words drove home. For a breathless moment all speech seemed to falter in abeyance, then every voice raised as one. "Cosmic rays!" gasped Dr. Bryant. "A weapon which shoots gamma radiation?" echoed the cherubic Eurasian, Dr. Anjers. "Fantastic!" Muldoon and the girl said as a single person, "Gary, you can't really believe--" [Illustration: Earth receded into an ominous distance.] "I _must_ believe," corrected Gary, "what my eyes tell me. There is only one conceivable explanation. As our chief here pointed out, the periodicity of gamma ray bombardment is one of the few invariables known to Man. Its constancy matches the monotonous regularity with which uranium transmutes to lead. "Scientists have traveled all over the world ... east, west, north, south ... but in every latitude and clime their Geiger counters measure the same tempo of cosmic ray bombardment. They have delved into the deepest mine-pits miles below ground, descended in bathyspheres to the ocean's floor, and detected no change. They have climbed the highest mountains, traversed space to our neighboring planets ... yet everywhere the rate of bombardment remains the same. "But here, here in this tiny room where, for an instant, a Geiger counter was bathed in the backwash of a strange, new, all-devouring flame, that instrument has registered the impact of a thousand direct hits! The conclusion is obvious. That radiation was--must have been--a concentrated discharge of cosmic rays." Dr. Bryant passed a hand through his white hair. "What you say is true, Gary. And it is certainly logical. Still--" "It is not so much the logic of our young friend's deductions I question," interrupted the other older scientist, "as the fantastic corollaries which necessarily follow his premise. To admit his rightness is to concede that somewhere, someone, for some unfathomable reason, designs the deliberate destruction--" "Of Earth!" said Nora Powell. "Not only of Earth, but of all the planets which circle our Sun. For as Gary has said, all these are bombarded, too, by cosmic rays. "Gary, there must be some mistake. There must be some freak coincidence--" * * * * * Lane's eyes narrowed. "That's just what it cannot be. The coincidence is too striking. Consider. For thousands of years men lived in blissful ignorance of the fact that they and their world were daily being bombarded by rays which science now has reason to believe are lethal.[2] During the past few hundred years men have been _aware_ of this radiation, but unable to do anything about it. They can neither analyze it, duplicate it in their laboratories, nor--indeed--determine its exact nature.