He straightened up and connected a cable from the generator to the Mark IV communicator which was a factory twin of Betsy. "I'm gonna feed this communicator half a micro-micro-watt of stuff like the broadcast--I think," he announced grimly. "I saw the diagrams of the transmitters they want us to make. I'm guessing the broadcast-wave they use is close to it but not exact. Close, because it's bad for machines. Not exact, because they're alive while they use it. I hope I don't hit anything on the nose. Okay?" Lecky said gently: "I have never been more frightened. Go ahead!" Sergeant Bellews depressed a stud. The communicator's screen lighted up instantly. It was receiving the generator's minute output and accepted it as a broadcast. But the signal was unmodulated, so there was no image nor any sound. * * * * * The communicator's standby light flickered steadily. Sergeant Bellews adjusted a knob on the generator. The communicator's standby flicker changed in amplitude. Bellews turned the knob back. He adjusted another control. The standby light wavered crazily. Graves said nervously: "I think I see. You are trying to make this communicator react as Betsy did. When it does, you will consider that your generator is creating a wave like the broadcasts from nowhere." "Yeah," said Bellews. "It ain't scientific, but it's the best I can do." He worked the generator-controls with infinite care. Once the communicator's standby light approached sine-wave modulation. He hastily shifted away from the settings which caused it. He muttered: "Close!" Then, suddenly, the communicator's lamp began to waver in an extraordinary, hysterical fashion. Sergeant Bellews turned down the volume swiftly. He wiped sweat off his forehead. "I--I think I got the trick," he said heavily. "It's a hell of a wave-type! Are you guys game to feed it into this communicator's output amplifier?" "I have six sets of cold chills running up and down my spine," said Lecky. "I think you should proceed." Howell said angrily: "It's got to be tried, hasn't it?" "It's got to be tried," acknowledged Sergeant Bellews. He shifted the generator's cable from the communicator's input to the feed-in for preamplified signal. The communicator's screen went dark. It no longer received a simulated broadcast signal. It was now signalling--calling. But the instant the new signal started out, the standby light flickered horribly. Sergeant Bellews grimly plugged in other machines--to the three scientists they looked like duplicates of Gus and Al--to closed-circuit relationship with Betsy's twin. The standby light calmed. "Now we test," he said grimly. "Got a watch?" Lecky extended his wrist. "Watch it," said Sergeant Bellews. He stepped up the output. "My watch has stopped," said Lecky, through white lips. Graves looked at his own watch. He shook it and held it to his ear. He looked sick. Howell growled and looked at his own.