There were tall metal boxes, like packing cases for heavy machinery, arranged in rows on the buckled and humped pavement of the chamber--metal boxes, each with a closed and perhaps hermetically sealed door. And near the farther wall was a machine--an engine or something--that displayed a gigantic, dusty fly-wheel. The walls, at a head-high level, were covered with something crystalline, like glass; though where it had bent it had bent like metal--not shattering as a brittle substance would have done. Behind those crystal panes were compartments, housing queer, complicated devices. They looked a little like astronomical or surveying instruments, Perry thought. Were they perhaps instruments for the navigation of interplanetary or interstellar space? Seeing charts traced on the walls above the compartments that protected this array of apparatus--charts dotted with winking, diamond-bright bits of glass, which must represent scattered suns of the void--he was half sure that his guess was right. The charts were marked with countless interlocking lines and circles, which might be the geometric equivalent of latitude and longitude, applied not to the navigation of the ocean, but to the limitless, three-dimensional reaches of the cosmos. This much Perry Wilcox was able to note, before his eager inspection was interrupted. In the heavy stillness there was a rustling whisper, which penetrated easily the thin, rubberized fabric of his hoodlike mask. The sound swiftly built itself up into a regular, soft rhythm. Perry spoke a few warning words about this development into his phone, and described briefly the room he was in. Meanwhile he stared ahead, ready in every taut nerve and muscle to leap out of danger, yet eager to see what it was that caused the disturbance. His lamp beam focused on the engine near the opposite wall. Its fly-wheel was turning, maybe after half a billion years of motionless waiting in this sealed vault. But why? How? Perry bounced back a step, icy fingers of dread tickling his flesh. "On your marks up there, Rod," he said tensely into his phone. "I can't tell what kind of a show it is I've started; but you may have to yank me up in a hurry!" * * * * * The engine was whizzing now, ancient dust spraying from its fly-wheel. For a few seconds there were no more developments, except that Perry noticed the decorative frieze around the high, shadowy ceiling. Human faces carved in the metal. They smiled down on the young man mysteriously. Then there was a soft clank in the far distance, muffled apparently by the turn of many passages, and echoed back and forth by crumpled, vaulted ceilings and walls. The sound might have been that of a door opening, or the rattling of chains. Perry was beginning to feel very much like beating a hasty retreat; but he waited a trifle longer.