"I've noticed the same thing," Nellon responded. "But an airlock--" He shook his head, for this was one of the many things he couldn't understand. Soon the corridor came to an end. Nellon and Austin found themselves in a small, square room, each side of which was lined with small glass cubicles or cabinets. In each reposed a transparent sphere with various inexplicable attachments and a compactly folded mass of some strange material. "Helmets!" Big Tim breathed. "Brad, those are helmets. And unless I'm mistaken the other stuff must be suits of some kind. What have we stumbled onto, anyway?" Nellon passed a slow, almost-knowing glance about the room, his helmet lights glinting on the glass of the cabinets. "I've got a crazy idea," he said. "But let that wait until we see more. There's another doorway over there. Let's go on." * * * * * They went on. There were more corridors, but this time there were rooms opening from them. Each was uniformly alike, filled with the same articles and furnishings. Nothing with which they were familiar had any counterpart here. Everything, from strange, rounded furniture to bizarre clothing, was weirdly alien. But of the beings who had once inhabited these rooms they found no trace. There were only the garments they had once worn, the chairs in which they had sat. About these clung the ghosts of their presences. Over all was an air of desertion and long neglect. They entered another section. Here there were rooms as large as halls, spread with queer tables and chairs. One they found to be a library, for on shelves they found large, tablet-like books whose stiff pages were covered with glowing hieroglyphs. Then they found their first stairway, a succession of small ramps leading to some floor above. They ascended slowly, with the feelings of men entering some new portion of strange and utterly alien world. Here they found but one, huge room, and this their lights revealed to be perfectly circular. In the center, glowing greenly, was what appeared to be an immensely thick column, rising from floor to ceiling. About this banks of strange instruments and machinery were grouped. "Brad," Big Tim whispered. "This place--What on earth could it have been for?" Nellon made small, slow shakes of his head. "That's what bothers me. I can't imagine any possible use. They knew utility, the beings who built these rooms. There was a good purpose for this room, I'm sure. Yet I can't imagine what it could have been. None of the activities which we normally carry on in life would seem to fit in with these surroundings." "Brad--that's it! This room was for no normal use. It was for something--oh, I don't know. But it must have been something tremendously important to them. I feel--" Big Tim did not finish. His strained, low voice died away, and he moistened his lips. The reverie heavy upon his face showed clearly how oblivious he was of the act.