"Get 'em back! Put 'em to work. Turn off those darned photomosaics and use the manual again. We've lost every beam we ever had." A sarcastic voice came in at this point. "For what reason do you interfere with my improvements?" sneered the voice. "Could it be that you are accepting graft from the employees to keep them on the job by preventing the installation of superior equipment?" Channing turned on his toe and let Burbank have one. It was a neat job, coming up at the right time and connecting sweetly. Burbank went over on his head. "Get going," Channing snapped at Thomas. Charles Thomas grinned. It was not Channing's one-ninety that decided him to comply. He left. Channing shook Burbank's shoulder. He slapped the man's face. Eyes opened, accusing eyes rendered mute by a very sore jaw, tongue, and throat. "Now listen," snapped Channing. "Listen to every word! Mosaic directors are useless. Know why? It is because of the lag. At planetary distances, light takes an appreciable time to reach. Your beam wabbles. Your planet swerves out of line because of intervening factors; varying magnetic fields, even the bending of light due to gravitational fields will shake the beam microscopically. But, Burbank, a microscopic discrepancy is all that is needed to bust things wide open. You've got to have experienced men to operate the beam controls. Men who can think. Men who can, from experience, reason that this fluctuation will not last, but will swing back in a few seconds, or that this type of swerving will increase in magnitude for a half-hour, maintain the status, and then return, pass through zero and find the same level on the minus side. "Since light and centimeter waves are not exactly alike in performance, a field that will swerve one may not affect the other as much. Ergo your photomosaic is useless. The photoelectric mosaic is a brilliant gadget for keeping a plane in a spotlight or for aiming a sixteen-inch gun, but it is worthless for anything over a couple of million miles. "So I've called the men back to their stations. And don't try anything foolish again without consulting the men who are paid to think!" Channing got up and left. As he strode down the stairs to the apartment level, he met many of the men who had been laid off. None of them said a word, but all of them wore bright, knowing smiles. By Monday morning, however, Burbank was himself again. The rebuff given him by Don Channing had worn off and he was sparkling with ideas. He speared Franks with the glitter in his eye and said: "If our beams are always on the center, why is it necessary to use multiplex diversity?" Franks smiled. "You're mistaken," he told Burbank. "They're not always on the button. They vary. Therefore, we use diversity transmission so that if one beam fails momentarily, one of the other beams will bring the signal in. It is analogous to tying five or six ropes onto a hoisted stone. If one breaks, you have the others."