Year after year the atom smashers had become bigger and bigger. There came a time when they could not be built on the surface of the Earth any longer, so a space laboratory was conceived, built around the doughnut of the ten-thousand-billion-volt proton synchrotron. Protons, whirling around for thousands of cycles in this vast doughnut, eighty miles in circumference, could acquire energies equal to those of the most powerful cosmic rays. Even mesons shattered at this energy. By inspecting the remnants of these broken mesons, scientists could begin to get some idea as to the ultimate structure of matter and energy. Now, Jim Britten thought, what was there about this work that should suddenly become too secret to be published? Peace had reigned on Earth for many years, and it was once more fashionable to think of science as being free and unbound by security regulations. But not, apparently, here in Glover's private domain. Rephrase the question, Britten thought. What was there about this work which had suddenly made it desirable for Professor Glover to take Britten off the project? Was there more to this experiment than Britten had seen up to the present? Sitting through the night, Britten thought and calculated, filling his desk top with paper, feeling the frustration of a scientist who spends day after day with the details of an experiment, pushing buttons, reading meters, soldering wires, until he begins to lose sight of the ultimate aim of the project. As he fell asleep, long towards morning, his anger was still at a furious temperature, filling his mind with dreams of a tormented, violent nature, which he forgot promptly upon awakening. * * * * * Professor Glover stopped by to see him as he ate a late breakfast. "We have a job to do today," Glover said, his voice tinged with an impersonal annoyance that was not directed at Britten. Britten stared up at Glover with a hostility that made no impression upon the scientist. "The ion source has gone bad and has to be replaced," Glover continued. "The spacesuits are being readied in the airlock." "Why us?" Britten complained. "What's the matter with the maintenance crew?" Glover's frown deepened. "They're busy with other things. You're free for the moment, and so am I." Then his face cleared, and he slapped Britten on the back. "Come on, fella, snap out of it. It'll do us both good to put on the suits and get out in free space." Britten uttered grumbling noises about "a guy can't even finish a cup of coffee," and followed Glover out to the maintenance lock nearest the ion source.