Crandall smiled wryly. "That's a relief," he said. "But I didn't have time to ask where that tube went. I might have blown up the administration building." Claverly laughed. "About all you've done is to cut a large hole in the coast-to-coast pneumo," he said. "No jury in the world would convict you." DeLieb came around from the other side of the building. "There," he said, "but for the Grace of God--" pointing at the billowing pillar of smoke. "Thanks, Dave. This makes you unique, you know." "Unique?" "You are the only living man who has seen one of those devils' rocks in operation." "We were all there," objected Dave, "and how about the Manhattan Crystal?" "In the first place, the Manhattan Crystal is furnishing New York with electrical power--from a generating plant twenty miles outside New York, telemeter-controlled, and completely unattended. Montrose and Crowley and their associates who first made the crystal went up trying to reproduce it at Brookhaven. So did Brookhaven. Harvard, Purdue, Caltech, and Argonne went up trying to make one, too." "But you were there, too, and you've seen it." DeLieb nodded. "It is a six-sided crystal about three inches long, with a pyramidal point at either end, and about three-quarters of an inch across the hexagonal flats. It is clear with a trace of blue tint. So much we know, Dave. _But what shape was it when you tossed it into the tube?_" "Cubical, and full of flashing red glints," said Dave. "And why were we suddenly scared bright green?" "Because it began to change shape before our eyes," said Dave. "And it was still fluid when we--left." "I think so," said Dave uncertainly. DeLieb turned and went into the laboratory again, with the others following. He inspected the anvil and straightened up with a wry smile. There was the dent on the soft iron, made by the crystal under Dave's blow. "That," said DeLieb, "is the impact of a hexagonal crystal slightly distorted. A hexagonal form half-changed to a cubical shape. So, Dave Crandall, you are the only man alive to have seen such a crystal. Who knows the shape of the Manhattan Crystal by now?" * * * * * Steps clicked along the other zigzags. Phelps came in through one. "No hits," he said, "one run, and the only error was shutting off the cross-country pneumo. Tough. But the country got along without the shipment of short-lived radioisotopes before and it'll have to do without them again until they get the tube put together. Nice going, Crandall."