To Westervelt's right, near the far wall behind which lay the communications room, he caught sight of a prowling figure. He recognized Lydman's broad shoulders and hesitated. The ex-spacer had paused to examine a gadget lying on one of the tables. From Westervelt's position, it appeared to be a wristwatch or something similar. Lydman picked it up and turned toward a part of the wall where a thick steel plate had been fastened to an insulated partition of brick. He raised the "watch" to eye level, as if aiming. A thin pencil of white flame leaped from the instrument to spatter sparks against the already scarred and stained steel. Sucked up by the air-conditioning, the small puff of smoke disappeared so quickly that Westervelt realized that the scorched odor was entirely in his imagination. Lydman replaced the instrument casually before strolling over to another table. He inspected an open pack of cigarettes with a grim smile, but let them lie there in plain sight. Westervelt reminded himself never to grub one of those, just on general principles. Lydman went on to a small cylinder somewhat larger than an old-fashioned battery flashlight. Something clicked under his finger, and from one end of the cylinder emerged the folding blades of a portable fan. The ex-spacer pressed a second switch position to start them spinning. He turned the fan to blow across his face, as if to check its cooling power, then held the thing at arm's length as he thumbed the switch to a third position. A low, humming sound reached Westervelt. It rose rapidly in pitch until it passed beyond his hearing range. He shook his head slightly. For some reason, he found it difficult to concentrate. Perhaps Lydman's presence, unexpected as it was, had upset him, he thought. He decided that he must be getting a dizzy spell of some sort. Then he became concerned lest he turn nauseous. The final stage, hardly a minute after Lydman had last moved the switch, found Westervelt tensing as a wave of sheer panic swept over him. He stepped back toward the door, noticing dizzily that Lydman wore a strange expression too. Part of the youth's mind wondered if some of the ultra-sonic effect were reflected from the walls to the ex-spacer; another part insisted upon leaving the scene as hastily as possible. He got himself into the corridor again, actually panting as he eased the door closed behind him. He started to walk, finding his knees a trifle loose. Passing the washroom, he hesitated; but he decided that he could make it to the conference room. Once there, however, he slipped inside and sat down to recover. "What does it take to have a mind like that?" he whispered to, himself. "It's like a hobby to him. I think some day I ought to look for a job with reasonably normal people!" A few minutes of peace and quiet refreshed him. He returned to the main office, just as Smith was surrendering a stack of signed letters to Simonetta Diorio. They looked around as he entered.