Phil grabbed Dytie's wrist. His other hand, fumbling blindly, found an invisible rung in the air. So did his foot. He scrambled up the air and pitched over the sill of the inky doorway, into an inky sack and found a curving floor under him. Rolling over, he saw behind him a rectangle of the sky with three stars in it. The rectangle narrowed and vanished, and there was no light at all. Then he started to fall. XVII Phil struck out wildly, with the instinctive hope that a man falling to his death could warp space to his advantage if he tensed his muscles sufficiently. Then he wondered how long it would take a man to fall fifty floors, but the mathematics were beyond anything he could do quickly enough in his head. Then he asked himself why the inky sack was falling with him. Then he retched, but brought up only the ghosts of a yeast-spread sandwich and a glass of soybean milk consumed a day ago. He continued to fall. Soft light sprang up around him. He was inside a sphere some eight feet in diameter and his feet were near the center, while his cheek gently brushed the sphere's soft lining. Swiveling his gaze past his feet, he noticed Dytie da Silva sprawled negligently in the air and intently studying a screen set in the lining of the sphere. But he was still falling. Phil knew little enough about space ships, but he knew they couldn't safely go into free-fall without accelerating first to get some kind of edge on earth's gravitational field. But there had been no acceleration. "Dytie!" he yelled, and in the confined space the noise was deafening. "What's happening to me?" Wincing a bit, she looked around at him. "Shh, Phil. You in free-fall but not falling. I turn off grav'ty." Still retching, Phil tried to comprehend that idea. "Turn off gravity?" He was still falling, but no longer so sure he was going to hit anything. Dytie looked along his helplessly sprawled body at his face. "Sure, Phil. Grav'ty go round this little boat just like light do. Grav'ty no pull it, light no show it." "That's why it was invisible?" "Vis'ble? Nobody see it. Wait bit, Phil, got do things." "But in a ship like this you could travel--" Phil began, his mind suddenly full of dizzying speculations. "This not ship, Phil, just dinghy. No talk now." Phil's falling acquired a direction. He found himself drifting gently toward Dytie. "Here 'side me, Phil," she instructed. A few moments later he was comfortably stretched out on his stomach beside Dytie, his head poised like hers above the screen. And then the speed of his new directed fall increased, although the sphere was no longer falling with him, until his body was comfortably pressed against the soft lining. He deduced after a while that they must be accelerating, although he got his chief clue from the screen.