"There's no path near here. You know that perfectly well," said the principal. "There's a wide stretch of grass beyond the flower bed and no one's allowed to walk on it! I've had my eye on that boy...." * * * * * Howard Dax thought this over. Come to think of it, he wouldn't put such a thing past the young smart-alec. Hoodlumism doesn't necessarily advertise itself in the classroom. He looked at the principal. The man had a nerve to accuse _him_ of seeming half asleep! Working in his private lab after dinner and then at his desk until all hours, struggling to learn Middle English--or rather, transitional Anglo-Saxon. He had done well at English lit at college, even though majoring in science, and Chaucer had come fairly easy to him. But Twelfth Century speech--and that was what he had to learn--was something else again. Chaucer himself couldn't have understood it. He wondered what young Mallison and his hipster friends would think if they knew his secret occupations. He could just imagine the sneering. "Well, you _could_ be right, I suppose," he said. "He's not my--shall I say?--favorite pupil." "I'm glad you think I could be right," Mr. Lightstone said. "I intend to hold an investigation. At the first possible opportunity. This very evening, in fact. At my office, and I shall have young Mallison brought before us. I shall expect you." He got up and strutted out of the class room. After a few moments Howard Dax followed him. Outside, on his way to the gate, he passed Mallison, who was standing talking to another boy who had a similar haircut, but was unfamiliar to the physics teacher. He thought he was not a pupil of this school. They both became silent as he drew near them, looking at him without any expression. Dax wondered if narcotics could be responsible for Mallison's pallor. After dinner Dax went into his little lab, which was actually the kitchenette he never used. On the table and sink was some chemical apparatus. The principal's remark had been ill-chosen since Dax at college had started with chemistry as his major and had only switched to physics in his senior year. He had also become interested in genetics, and it was this all-around interest in the sciences that had perhaps militated against him. Nowadays one ought to specialize. Well, he was specializing now. In an evaporating dish in the sink were some dark brown crystals that his landlady would have taken for Damerara sugar, but which had a considerably more complex formula. They would have lent a rather odd flavor to Indian pudding. The logic which had given rise to this formula was not merely complex but revolutionary. It involved the concept of reversibility of entropy--the application of which was itself unprecedented.