Then earth and flower-sod alike were sliding. Loose loam cascaded over Boone. Desperately, he tried to find Eileen amid the welter. "Here, Fred! Behind you!" Floundering, Boone craned to see her. She stood close to the shell's wall, braced against it. Then another tremor threw him flat; half-buried him. Clawing, cursing, he wallowed towards the girl. She darted forward in the same instant. Her hand locked on his. With a final effort he shook free of the clods and lurched panting to a place at the wall beside her. Another jolt. Again the earth slipped from beneath his feet. Yet now, since he had the wall to brace him, the surge of movement did not fell him. Then it dawned on him that the shell itself was sliding, sliding upwards! It was Eileen who gave the answer: "Lean back, Fred! The bubble's rolling, that's all. The dirt keeps sliding forward." Strangely, her voice was steady now; calm, almost. After that, there was no more time for talking. Faster and faster, the grey sphere careened onward, bumping and bouncing. A dozen times, one or the other of them fell. But as long as they held their places against the rear wall, the earth and clods spilled away from them, so that with sweat and scrambling they managed each time to regain their footing. Then, at long last, the strange globe slowed and changed direction. The surface beneath it seemed smoother now, and the bubble moved in arcs and curves. Shadows fell across it. The light grew dim, then faded altogether. More movement, through long lanes of utter darkness. Strange sounds, faint whispers in the stillness. Then, abruptly, light again--a blaze of it, dazzling and incandescent. The bubble halted. A crash of silent thunder, more felt than heard. Its impact pitched Boone and Eileen forward into the dirt. The globe split into segments like a quartered orange. Half-stunned, they stared about. * * * * * It was a chamber such as Boone had never seen before--a great, bare bubble-room whose very walls radiated chill white light. Lurching to his feet, he stumbled down from the tumbled earth. Two steps he took. And then, incredibly, he could go no further, for out of nowhere, a new bubble, crystal clear and barely large enough for him to stand erect, had formed around him. He spun about. Like him, Eileen stood in a solitary global prison. Stiff-faced with fear, she gestured to him--helpless, hopeless. He hammered at the shimmering wall in furious frenzy. But to no avail. The casing gave no more than had that of the cell in which he and Eileen had come. His sphere began to move away from Eileen's, then. Like a huge ball it rolled, spinning out in an arc that carried it through some unseen exit that led from the chamber of chill white light. Darkness again. But only briefly, this time. Then, once more, the globe halted. New light came, a warm and golden glow. Again, Boone peered forth.