"They shouldn't allow those buzzing things in the hospital. They make more noise than a whirlybird." She backed away, tugging at the white-coated arm until her chin was released. "I mean I saw them yesterday. They tried to get in the bird. I don't know why _they_ visit him--he can't say a word. Doesn't he have a family?" "No, but the Silvertongue men love him like a brother. Barger designed their radiocompressor--the one in all the newspapers. Here, you can see it from the window if you--" "I know, Dr. Brooks." "Do you know what that machine can really do, girlie?" "When I was your age--" Miss Knox began. "You are. I just _look_ young. That machine can cure and shred tobacco with supra-short waves on a polished magnesium bowl, just the way the papers say, but they have cheaper ways to process their tobacco. They really use the machine for guided tours of the factory. Public relations." "You mean float visitors through the air?" "No. You'd need the power of ten maritime atomic piles in series just to lift Dr. Gesner to the height of--" "Very funny!" "--his own square root. What they can do with that machine is to disguise an object--say the incoming leaf tobacco. They can make it look firm, golden, and so forth. The girls at the sorting tables, wherever the guided tour happens to be, will all look like Norma Norden. They'll be dressed as angels and work in heaven. Then the V.I.P.s can tour the girls' homes and dormitories, and instead of a dirty slum, they'll see--they'll see _mushrooms_, if they like." "How is it done?" "Only Barger Electronics really knows," said Dr. Brooks, "and the Christian E. Lodge engineers. It's something to do with compressing the wave length to approximate that of light, so that images are canceled out. This leaves a clear field for subliminal techniques. If there are subvisual images projected on the walls, for instance, that's what the observers will see inside the room." "Oh, my God!" exclaimed Miss Knox. "The only other thing I know is that it has to be done with intersecting spheres. The machine has two portable secondary transmitters--or projectors, or whatever they call them--each emitting in all directions to form a wave-sphere. Where the two spheres overlap, you get your possible interference with light." "Frankly, I just don't understand it." "Any radio waves go out in all directions to form spheres." His voice had become a mutter. "You know that." "No, I didn't." * * * * * He gave a false sigh. "Well, take an ordinary weak phone transmitter very high up in a whirlybird. That's the simplest case. You know what sound a whirlybird makes, don't you?" "Of course," said Miss Knox. "What?" Dr. Brooks challenged, moving at her. "How does it sound?" "Oh, clatter-clatter chug-chug," she said, moving back.