"Ain't in the least curious about medicine and never bothered to learn," grunted Vogel. "I keep my stuff running and that's all. I don't interfere with nobody and they don't come around and get friendly with me." Cameron believed it. The statement fit the personality. He needn't be concerned about fraternization. "There are a few things that puzzle me," he began. "That's why I called you in. Usually we maintain about half Earth-normal gravity. Is that correct?" The engineer nodded and grunted assent. "I'm not sure why half gravity is used. Perhaps it's easier on the weakened bodies of the accidentals. Or there may be economic factors. Either way it's not important as long as half gravity is what we get." "You want to know why we use that figure?" "If you can tell me without getting too technical, yes. I feel I should learn everything I can about the place." The engineer warmed up, seeming to enjoy himself. "Ain't no reason except the gravity units themselves," Vogel said. "Theoretically we can get anything we want. Practically we take whatever comes out, anything from a quarter to full Earth gravity." "You have no control over it?" This contradicted what he'd heard. His information was that gravity generators were the product of an awesome bit of scientific development. It seemed inconceivable that they should be so haphazardly directed. "Sure we got control," answered the engineer, grinning. "We can turn them off or on. If gravity varies, that's too bad. We take the fluctuation or we don't get anything." Cameron frowned; the man knew what he was doing or he wouldn't be here. His position was of only slightly less importance than that of the medical director--and where it mattered the Medicouncil wouldn't tolerate incompetence. And yet---- The engineer rumbled on. "You were talking how the generators were designed especially for the asteroid. Some fancy medical reason why it's easier on the accidentals to have a lesser gravity plus a certain amount of change. Me, I dunno. I guess the designers couldn't help what was built and the reason was dug up later." Cameron concealed his irritation. He wanted information, not a heart to heart confession. Back on Earth he _had_ been told it was for the benefit of the accidentals. He'd reserved judgment then and saw no reason not to do so now. "All practical sciences try to justify what they can't escape but would like to. Medicine, I'm sure, is no exception." He paused thoughtfully. "I understand there are three separate generators on the asteroid. One runs for forty-five minutes while two are idle. When the first one stops another one cuts in. The operations are supposed to be synchronized. I don't have to tell you that they're not. Not long ago you felt your weight increase suddenly. I know I did. What is wrong?"