Astounding Stories of Super-Science, August 1930

Indeed, that was his own fondest hope--their imperative need, if the people of America and of the earth were to be saved from this appalling menace. But what basis was there for such a fantastic hope? Just one, that he could see. "That thing on your wrist," he said, voicing it. "I'm surprised they let you wear one of those." "They don't," she smiled. "I stole it!--from one of the maids in my apartment. It was the only way I could get here without being seen. I felt I must see you at once. We've got to do something, soon, or it'll be too late. I felt that, as a scientist, you might have some idea how we could get off." "How do the people themselves get off?" he asked. "That escalator ray--do you know how they use it?" "No, I've never been able to find out. They don't let me go near that part of the city." Kendrick reflected a moment. "Let's have a look at that invisibility affair," he said. She removed it from her wrist, handed it to him. Somewhat in awe, he examined it. The mechanism portion, which was linked in a strap of elastic metal, resembled only superficially a watch, he now saw. Rather it had the appearance of some delicate electric switch. Rectangular in shape, it was divided into two halves by a band of white crystal. In each of these halves were two little buttons of the same material, those on one side round, on the other square.