"We need," said Calhoun, "an interruptor that will cut off the power broadcast for the half-second the ground-induction field is supposed to be on. Then it should turn on the broadcast power for the second and a half the cattle fence is supposed to be off. That will stop the cattle-fence effect, and I think a ground car should be able to work with power that's available for three half-seconds out of four." The electronics men blinked at him. Then they grinned and set to work. Calhoun went exploring. He found a lunch box in a desk with three very stale sandwiches in it. He offered them around. It appeared that nobody wanted to eat while their families--at the end of the highway--were still hungry. The electronics men called on the two mechanics to help build something. They explained absorbedly to Calhoun that they were making a cutoff which would adjust to any sudden six-million-kilowatt demand, no matter what time interval was involved. A change in the tempo of the cattle-fence cycle wouldn't bring it back on. "That's fine!" said Calhoun. "I wouldn't have thought of that!" He bit into a stale sandwich and went outside. Allison sat limply, despairingly, in his seat in the car. "The cattle fence is going off," said Calhoun without triumph. "The people of the city will probably begin to get here around sunrise." "I--I did nothing legally wrong!" said Allison, dry-throated. "Nothing! They'd have to prove that I knew what the--consequences of the research project would be. That couldn't be proved! It couldn't! So I've done nothing legally wrong...." Calhoun went inside, observing that the doctor who was also tennis champion, and the policeman who'd come to help him, were keeping keen eyes on the city and the foundations of the grid and all other places from which trouble might come. There was a fine atmosphere of achievement in the power-control room. The power itself did not pass through these instruments, but relays here controlled buried massive conductors which supplied the world with power. And one of the relays had been modified. When the cattle-fence projector closed its circuit, the power went off. When the ground-inductor went off, the power went on. There was no longer a barrier across the highways leading to the east. It was more than probable that ground cars could run on current supplied for one and a half seconds out of every two. They might run jerkily, but they would run. * * * * * Half an hour later, the amount of power drawn from the broadcast began to rise smoothly and gradually. It could mean only that cars were beginning to move. Forty-five minutes later still, Calhoun heard stirrings outside. He went out. The two men on guard gazed off into the city. Something moved there. It was a ground-car, running slowly and without lights. Calhoun said undisturbedly: