"I'm trying to tell you," said Hedgerly, "that if I help you amass a fortune on speculation, this will be known fact by my time." "So?" "So," said Hedgerly, "the only thing I've done--the only thing that is historic fact--is that which I'm going to do for proof. Just one thing." "Go on." "I'm going to write something on this envelope. Then I'm--Wait. We'll do it. I came prepared." He wrote a sentence on the flap of the envelope and handed it to Joan. "Keep it carefully," he told her. "Now," he said to Graydon, "There will be a big nine-event day at Bay Meadows tomorrow. I have here a listing of nine horses. You will put a sum of money on these nags and you will become famous as the first man ever to win a complete nine-horse parlay." "Interesting if true," said Graydon, looking over the list. "We'll know tomorrow." "We'll go out to the track tomorrow," said Hedgerly. "What about Marie and Peter?" asked Joan. Hedgerly smiled. "True love," he said, "never runs smooth. Peter and Marie are busy playing Gin Rummy now, and both of them agreeing that they'll have none of this. But propinquity--" The low growl in Graydon's throat stopped him cold. Perhaps his history told him to stop. * * * * * The roaring hum of the generator made speech difficult but not impossible. Marie, with pencil in hand, was interestedly recording the data that Peter was calling to her. His lips brushed her ear occasionally because it was necessary to get the figures across through the din. The brush of lip against ear was not unnoticed; under the circumstances it was hard to ignore anything, even the least minute of personalities. Finally he snapped the switch and the roar died. "That's it!" he said exultantly. "It's beyond me," said Marie, looking dazedly at the solid bank of figures she'd written down. "That's because you've never been exposed to the stuff before. Come on--I'll show you." He snapped the safety switch and watched the last dying flicker of the radiation counter above the control panel. Then he pressed a button and a huge door creaked open. He led Marie along a zigzag hallway, explaining, "Radiation products, like all Chinese Devils, travel only in straight lines." Then, inside of the shielding, she saw the generator. "This made that terrible racket?" she asked. He nodded. "I'd hate to be inside here when it's running," she said nervously. "Me, too," he grinned. "But I daresay the radiation would kill you long before the noise did." "Oh!" she gasped, getting the implication of the dangers of nuclear physics in one gulp. "This," he said, "is brand new. In the center is a small, thin-walled brass container filled with radon gas, and suspending a cloud of finely divided beryllium. This produces neutrons. Very slow neutrons not worthy of mention compared to most nuclear reactions. However this is but a source instead of a complete deal.