"Soft magnets," explained Thorn. "As simply as I can put it, my process for rendering an object invisible is this: I place the object, coated with the film, on this plate. Then I start in motion the overhead ring, creating an immensely powerful, rapidly rotating magnetic field. The rotating field rearranges the atoms of this peculiarly susceptible film of mine so that they will transmit light rays with the least possible resistance. It combs the atoms into straight lines, you might say. With that straight-line, least-resistance arrangement comes invisibility." "I don't quite see--" began the Secretary. "Refraction of light," said Thorn hurriedly. "The light rays strike this film, hurtle around the object, it coats--at increased speed, probably, but there are no instruments accurate enough to check that--and emerge on the other side. Thus, you can look at a body so filmed, and not see it: your gaze travels _around_ it and rests on objects in a straight line behind it. But you'll see for yourself in a moment. Pull that switch, there, will you? And leave it on for two full minutes after you have ceased to see me." Straight and tall, a figure encased in shimmering crystal, the scientist stood on the metal plate. Hesitant, with the superstitious dread growing in his heart, the Secretary stood with his hand on the switch. That hand pulled the switch down.... Soundlessly the overhead metal ring began to whirl, gathering speed with every second. And then, though he had known in advance something of what was coming, the Secretary could not suppress a shout of surprise. The man before him on the metal plate was vanishing. * * * * * Slowly he disappeared from view--slowly, as an object sinking deeper and deeper into clear water disappears. Now the face was but a white blob. Now the entire body was but a misty blur. And now a shade, a wavering shadow, alone marked Winter's presence. The Secretary could not have told the exact instant when that last faint blur oozed from sight. He only knew that at one second he was gazing at it--and at the next second his eyes rested on a rack of test-tubes on the wall beyond the plate. He looked at his watch. Sweat glistened in tiny points on the hand that held the switch. It was all so like death, this disappearance--as if he had thrown the switch that electrocuted a man. The specified two minutes passed. He cut off the power. The great ring lost speed, stopped whirling. And on the plate was--nothing. At least it seemed there was nothing. But a moment later a deep voice sounded out: "I guess I'm invisible, all right, according to the expression on your face." "You are," said the Secretary, mopping his forehead, "except when you speak. Then I have the bizarre experience of seeing glimpses of teeth, tongue and throat hanging in mid-air. I'd never have believed it if I hadn't witnessed it myself! That paint of yours is miraculous!"