"We'll be back to talk to the boy in a day or two," Marshall told her. "In the meantime, we'd prefer him not to be forewarned." "If you say so," she said, frowning. * * * * * The school principal, a gray battleship named Miss Evita Dexter, was irate. The idea that pornographic materials were being sold in _her_ schoolyard was absurd. It was ridiculous. It was unheard-of. Stevenson assured her that, adjectives notwithstanding, it was happening. And they were going to have a shakedown of the student body whether Miss Dexter liked it or not. Detective-Sergeant Stevenson and his associates, Marshall and Lang, were going to go through the student body with a fine tooth comb. Neither Marshall nor Lang had mentioned the fact that they were from the FBI. The search began at nine forty-five in the morning, and ended at ten past twelve. On the persons of three eighth-grade boys, they found pornographic photos. On the person of Eddie Clayhorn, they found absolutely nothing.... Abner Streitman Long was a government expert. He was more or less a government expert in the ready reserve, since he had never once been called upon to use his expertise for the government. Not until now. Abner Streitman Long was Resident Professor of Psychology at Mandar University. He was also one of the world's foremost and best-known experimenters in the area of parapsychology, also called Extra-Sensory Perception, also called psionics. The government, as a matter of principle, didn't believe in psionics. But the government, also as a matter of principle, kept a psionics expert handy, just in case. The "just in case" had maybe happened. Professor Long sat in Marshall's office and listened stolidly to the problem. The expert was a tall, barrel-chested man with a fantastic shock of white hair exploding out in all directions from his head. His nose was bulbous, his jaw out-thrust, his eyes deepset, his ears hairy, his hands huge and his feet huger. He looked like a dressed-up lumberjack, of the old school. He listened, and they talked, and every once in a while he nodded, and said, "Huh." His voice was, predictably, basso profundo. * * * * * Then they were finished, and Professor Long summed it all up. "He changes the temperature of objects. Yes?" "Yes," said Marshall. "You looked for a machine. Yes?" "Yes, and we didn't find it." "And your thermodynamics people said no such machine could exist anyway, yes?" "That's right." "Then why did you look for it?" "Because," said Marshall desperately, "we'd seen it in action. That is, we'd seen the result of its use." "Yes," said the professor. He sucked on his lower lip and abstractedly watched his thumbs twiddle. "Pyrotic," he announced at last. "I beg your pardon?" asked Marshall. "Pyrotic," repeated the professor. "Yes? Yes. Pyrotic. Do you know what that is?" "No," said Marshall.