He wasn't too sure about the large propulsion unit in the tail of the ship, either. Basically, it was a ram-jet unit. It ought to work, but it might not work too well.... * * * * * Morrow tossed down his pencil and slide-rule, sighing, then pressed his hands over his aching eyes and rose from the table. _It's too much for one man!_ he thought bitterly, and dropped his hands to his sides. He stood gazing into the deep gloom of the workshop, at the huge, black hull gleaming softly in the darkness. Fifty-five feet long and fifteen feet high, the ship rested patiently on the narrow runners that supported its sleek belly. Twenty-five hundred dollars and six weeks of cautious, painstaking work rolled into one beautiful, fantastic-looking black monster with curved fins around the cluster of "rocket" tubes in its tail and streamlined, submarine-type diving vanes near its nose. Those vanes had been Smitty's contribution, operating on a cross-control system to bank the ship and lift it around a turn as the aileron-elevators did on flying wing aircraft. No other control surfaces were installed; the long, sleek rudder fin was immovable. The night wind soughed through the forest on some nearby mountain slope. The ship stood black and silent, gleaming softly in the deep gloom of the workshop. It was a weirdly beautiful thing, like some creature of the Unknown. _Straight out of the science-fiction magazines!_ Morrow mused, grinning. _If Gwyn could only see it--_ A vision of her rose into his thoughts: Gwyn, lying on her stomach, the tight roll of her swimming trunks about her thighs, the smooth, tanned skin of her slender body, the firm swell of a breast beneath her armpit, the sunlight glints on her brown hair and the cool, calm wariness in her eyes.... Morrow grimaced wryly. Gwyn again! He'd been thinking entirely too often of her, and too much, since he'd left Westerton. He kept telling himself she was just another of the sacrifices he'd been forced to make, another part of his life he'd had to deny himself-- Still, when he slept he dreamed. He was just too damned young, he told himself harshly. The demands of his body were strongest at his age; it wouldn't let him alone. His instinct to mate, to reproduce his kind, demanded satisfaction. There was danger in that. If he fought it, denied it, kept it bottled up inside him, it could spread and infest his whole being until it became a perverse fixation on sex. He had to have some outlet for it. Time off from his work, time to relax and enjoy female companionship, the nearness of a woman. An older man, in whom the mating lust had had time to diminish until it wasn't quite so strong and insistent--an older man could retire and live in an ivory tower of science. He couldn't. He must make allowance for it. Find himself a girl in town. A date, a little moonlight and soft talk. Forget about a girl three thousand miles away. Forget Gwyn....