He led the way out of this room of many motionless but operating machines. The incredibly perfect vision-screen images still portrayed the cosmos outside with all the stars and the sun itself moving slowly across their plates. They saw sunshine and starlight shining on the broken, chaotic outer surface of the asteroid. Wavering, curiously writhing red specks on the ten-foot disk continued their crawling motion. Keller fairly glowed with enthusiasm as he began to investigate this apparatus. They all went back to the ship, except for Keller. They retraced their way along the long and brilliantly lighted galleries. They descended ramps and went along more brilliantly lighted corridors. Then they came to the branch which had been blocked off by a door that would not open. It was open now. They could see along the new section for a long, long way. They passed places where other doors had been closed, but now were open. What they could see inside them was almost exclusively a repetition of what they saw outside of them. They passed the place where hundreds of ten-foot metal spheres waited for an unknown use. They passed the table with a single leg, and the compartment with many metal ingots stored in it. Finally, they came to the door with rounded corners, went through it, and there was their ship with its air-lock doors open, waiting in the brightly lighted tunnel. They went in, and the feeling was of complete anticlimax. They knew, of course, that they had made a discovery beside which all archæological discoveries on Earth were trivial. They had come upon operating machines which must be old beyond imagining, unrusted because preserved in emptiness, and infinitely superior to anything that men had ever made. They had come upon a mystery to tantalize every brain on Earth. The consequences of their coming to this place would re-make all of Earth's future. But they were singularly unelated. "I'll make up a sort of report," said Burke heavily, "of what we saw as we arrived, and our landing, and that sort of thing. We'll get it in code and ready for transmission. We can use the asteroid's transmitter." Holmes scowled at the floor of the little ship. "You'll make a report, too," said Burke. "You realized that this is a fortress. There can't be any doubt. It was built and put here to fight something. It wasn't built for fun. But I wonder who it was meant to do battle with, and why it was left by its garrison, and why they set up a transmitter to broadcast when something happened! Maybe it was to call the garrison back if they were ever needed. But thousands of years--You make a report on that!" Holmes nodded. "You might add," said Pam, shivering a little, "that it's a terribly creepy place."