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.
"The neutrons emerge from the container in all directions, but are urged into motion by a swift increasing pulse of gravitic force. It used to be magnetic, but it is now gravitic. We've changed it over according to my findings of recent work. Then with the neutrons moving in a cloud, we alternate the gravitic field, varying it from attraction to repulsion. Just like a cyclotron uses radio frequency energy in the Dee Plates, we use gravitic energy to accelerate neutrons.