O'Hara was back in London two years later, on his way to Stockholm for reassignment. I picked him up at his flat in Bloomsbury. He wore by then the three gold bars and half-globe of a lieutenancy, and in his brilliant blue uniform he seemed more than ever to me a man set apart, for not many Patrol pilots and none like O'Hara were walking the streets of London, so far removed from their duty routes. He had put on weight, a good deal of it, yet he had managed somehow to absorb it compactly--six feet three and a good two hundred and thirty pounds, his dark face burned and weathered, only less dark than a Polynesian, and his thick, clustered hair jet black--for his prediction had not come true, he was no auk's egg. "What happened?" I asked him. "The atomic sickness?" We were lunching together at Swall's, where the roast is excellent, and O'Hara finished his before he answered me. "I'd forgotten that," he said at last. "You get over it. I suppose you build up a tolerance for it. The first year is a little rough--you can spot a cadet immediately by his red-rimmed eyes and the unhealthy color that comes through windburn pallidly, like an underglow of yellow. And this although they're never bucking more than .165 milliroentgens an hour. Then all at once, within a month's time, you're over the hump and it goes away and you're safe enough at .225--you're safe enough, that is, for short periods of time, and unless you're a damned fool and ram yourself into the Curtain. You don't tolerate that--though you never realize it. For you don't have time. You're cinders rather instantly." "You lose cadets?" "A percentage--a definite percentage--three out of ten. They simply cannot seem to learn that all of this has been estimated exactly and that there is no margin for error. The Curtain is constant, and the pattern of your flight must be constant, barring the variations caused by gales, for which there is a single rule--get the hell down south before your craft is slammed into the Curtain. We had a new man last summer, though--" He paused, his shoulders hunching forward and his eyes seeing beyond me, beyond Swall's, back into the Antarctic. His fingers tapped three times, slowly, upon the table. "Yes?" I said. O'Hara jumped. It seemed incredible, but he did exactly that, he jumped, as if I had screamed out at him. "Excuse me," he said, and laughed quickly. "Lost myself for a moment. Because we've never known precisely what it was. A mistake in his readings, certainly. He must have been confused, which can and does occur when inexperienced men are making those long overwater hops. Perhaps their vision blurs. And possibly--well, we ought not to get that type, they should screen them out, but there's considerable pressure for replacements, losing 30 per cent. If a candidate can pass the twenty-twenty test he's taken, but there should be a sharp downgrading on fatigue and on emotional reaction." "Surely they get emotion ratings?"