There was no doubt at all that his loot was being used to make instruments and devices of unknown kinds. He had used several of them on his raids. The one that could apparently phase out any electromagnetic frequency up to about a hundred thousand megacycles--including sixty-cycle power frequencies--was considered a particularly cute item. So was the gadget that reduced the tensile strength of concrete to about that of a good grade of marshmallow. After he had been operating for a few years, there was no installation on Earth that could be considered Nipe-proof for more than a few minutes. He struck when and where he wanted and took whatever he needed. It was manifestly impossible to guard against the Nipe, since no one knew what sort of loot might strike his fancy next, and there was therefore no way of knowing where or how he would hit next. Nor could he ever be found after one of his raids. They were plotted and followed through with diabolical accuracy and thoroughness. He struck, looted, and vanished. And he wasn't seen again until his next strike. Colonel Mannheim, who had carefully puffed a cigar alight and smoked it thoughtfully during Stanton's recitation, dropped the remains of the cigar into an ash receptacle. "Accurate but incomplete," he said quietly. "You must have made some guesses. I'd like to hear them." Stanton finished the last of his coffee and glanced at Dr. Farnsworth. The biophysicist was thoughtfully looking down at his own cup, his expression unreadable. _All right_, Stanton thought, _he's looking for something. I'll let him have both barrels and see if I hit the target_. "I've thought about it," he admitted. He got up, went over to the coffee urn, and refilled his cup. "I've got a pet theory of my own. It's just a notion, really. I wouldn't dare reduce it to syllogistic form, because it might not hold much water, logically speaking. But the evidence seems conclusive enough to me." He walked back to his seat. Colonel Mannheim was watching him, a look of interest on his face, but he said nothing. "To me," Stanton said, "it seems incredible that the combined intelligence and organizational ability of the UN Government is incapable of finding anything out about one single alien, no matter how competent he may be. Somehow, somewhere, someone must have gotten a line on the Nipe. He must have a base for his operations, and someone should have found it by this time. "I may be faster and stronger and more sensitive than any other living human being, but that doesn't mean I have superhuman powers, or that I'm a magician. And I'm quite certain that you, Colonel, don't credit me with such abilities. You don't believe that I can do in a short time what the combined forces of the Government couldn't do in ten. Certainly you wouldn't rely too heavily on it. "And yet, apparently, you are.