Astounding Stories of Super-Science, August 1930

"Which buttons control the invisibility?" he asked. "The square ones," she replied. "One's pushed in now, you see. If you should push the other, the first would come out--and you'd pass out of the picture, so to speak." Kendrick was half tempted to try the thing then and there, but deferred the impulse. "What are the round buttons for?" he inquired instead. Marjorie didn't know, but thought they were probably an emergency pair, in case something went wrong with the square ones. In any event, nothing happened when you pushed them. Kendrick pushed one, just to see. It was true. Nothing happened--but he seemed to sense a faint, peculiar vibration and a wave of giddiness swept over him. On pushing the other, which released the first, it stopped. He handed the device back to Marjorie. "There's your bracelet. Now, if I can just get one like it, I think we'll get down to earth all right." "Oh, Mr. Kendrick!" Her eyes lit up eagerly. "Then you've thought of a way?" "Not exactly. I think I've discovered their own way. I can't be certain, but I'm willing to gamble on it, if you are." "Then you--you think those round buttons are connected with the escalator rays?" "Exactly! I think they control individual descent and ascent, just as the square ones control individual visibility and invisibility. At any rate, it's the hunch I'm going to act on right now, if you're with me." "Oh, I'm with, you!" she breathed. "Anything, death almost, would be preferable to this."