Johnny Thompson started, then stared with dilated pupils at a spot on the aluminum casting before him. The spot, a jagged notch left by imperfect work in the foundry, turned first a dull red, then a bright red, then a glowing white. Mechanically his hand touched the valve of his oxy-acetylene torch. Yes, it was as he had believed, the acetylene valve was closed. The oxygen valve was open, it was true, but the drum which had contained oxygen under a thousand pounds pressure was empty. In fact, he was waiting for the arrival of a new drum. That was what made the thing seem strange, impossible It was a miracle, only miracles don't happen in such places-he was working in the heart of a great industrial plant which turned out automobiles in twenty carload lots and airplanes by the hundreds. Johnny scratched his chin and stared at the white spot. True, the nozzle of his torch was aimed at that spot; but five minutes before it had sput-sputted for a few seconds, then died down to an insignificant flame giving too little heat for any sort of welding. He had cut that flame off, yet now, before his very eyes the metal glowed white hot. With a grin which said plainer than words, "I'm dreaming," he thrust a finger in a can of water, then held it over the glowing spot until a drop of water fell. Instantly he started afresh and stared with wilder eyes. There had come the hiss of water on white-hot metal.