Blake, who had been watching the beam control instruments, said: "I don't know how he's done it, but he's managed to jam our radio beam! We're not getting any signal through!" The President's voice crackled in MacIlheny's ears. "Fitz! Detonate that bomb! We can't take any chances!" MacIlheny half grinned. "Major," he said, "set off the H-bomb." The major pressed a red button on the control panel. * * * * * Twenty minutes later, the screen came on again, showing the same scene as before. No one was surprised. By then, reports had come in that the satellite was still visible, still in its orbit. The H-bomb had failed to go off; the signal had never reached the detonation device. The alien was standing in front of the camera, holding a large piece of mechanism in his hands. On Earth, the thing would have been almost too heavy to lift, but the gravitational pull of Satellite Number Four was almost negligible. "_He's got the H-bomb!_" MacIlheny recognized the President's voice in his ears. The alien bowed toward the camera, then straightened and went back to his own ship. He clambered up the side of it with magnetic soles as easily as he had walked on the hull of the space station. Near the end of his ship, he opened a small door in the hull. Within was utter blackness. Working slowly and deliberately, he pushed the H-bomb into the blackness. It wasn't just ordinary darkness; it seemed to be an actual, solid wall, painted deep black. As the bomb went in, it looked as though it were cut off abruptly at the black wall. Finally, there was nothing outside except the two detonating wires, which had been clipped off from inside the Earth ship. The alien took the wires in his hands. "My God!" said the major. "He's going to blow up his own ship! Is he crazy?" "I don't think so," said MacIlheny slowly. "Let's see what happens." As the two wires came in contact, the black wall inside the small door became lighter, a pearly gray in color. There was no other result. "Well I'll be damned," said Blake in a low, shocked voice. The alien closed the door in the side of his ship and came back down to the camera. He bowed again. Then he pointed to the weapon that he had been carrying and waved his hands. He picked it up and brought it around the RJ-37. From the microphones inside the ship came a faint scraping sound. Then the alien reappeared in front of the ship. His arms were empty; he had put the weapon inside the open cargo hold. "A fair trade is no robbery," Blake said softly. The alien bowed once more, then turned on his heel and walked back to his ship. This time, he got inside and closed the door. Then the blue ship moved.