Before him there stretched a corridor which was not less than twenty feet high and just as wide. The long, glowing tubes of light that illuminated the ship–tunnel were here, too, fixed in the ceiling. The corridor reached away, straight and unbroken, until its end seemed a mere point in the distance. It looked about a full mile long. There were doorways in both its side walls, and they dwindled in the distance with a monotonous regularity until they, too, were mere vertical specks. One could not speak of the length of this corridor in feet or yards. It was a mile.
It was incredible. It was overwhelming. And it was empty. It shone in the glare of the light tubes which made a river of brilliance overhead. It seemed preposterous that so vast a construction should have no living thing in it. But it was absolutely vacant.
They stared down its length for long seconds. Then Burke seemed to shake himself.
"Here's the parlor. Let's walk in, even if there's no welcoming committee."
His voice echoed. It rolled and reverberated and then diminished very slowly to nothing.
Burke strode forward with Sandy close to him. Pam stared blankly, and instinctively moved up to Holmes. Once they were through the door, the sensation was not that of adventure in a remote part of space, but of being in some strange and impossible monument on Earth. The feeling of weight, if not completely normal, was so near it as not to be noticed. They could have been in some previously unknown structure made by men, at home.
This corridor, though, was not built. It was excavated. Some process had been used which did not fracture the stone to be removed. The surface of the rock about them was smooth. In places it glittered. The doorways had been cut out, not constructed. They were of a size which made them seem designed for the use of men. The compartments to which they gave admission were similarly matter–of–fact. They were windowless, of course, but their strangeness lay in the fact that they were empty, as if to insist that all this ingenuity and labor had been abandoned thousands of years before. Yet from somewhere in the asteroid a call still went out urgently, filling the solar system with plaintive fluting sounds, begging whoever heard to come and do something which was direly necessary.
A long, long way down the gallery there were two specks. A quarter–mile from the entrance, they saw that one of the rooms contained a pile of metal ingots, neatly stacked and bound in place by still–glistening wire. At half a mile they came upon the things in the gallery itself. One was plainly a table with a single leg, made of metal. It was unrusted, but showed signs of use. The other was an object with a hollow top. In the hollow there were twisted, shriveled shreds of something unguessable.
"If men had built this," said Burke, and again his voice echoed and rolled, "that hollow thing would be a stool with a vanished cushion, and the table would be a desk."
Sandy said thoughtfully, "If men had built this, there'd be signs somewhere marking things. At least there'd be some sort of numbers on these doorways!"
Burke said nothing. They went on.
The gallery branched. A metal door closed off the divergent branch. Burke tugged at an apparent handle. It did not yield. They continued along the straight, open way.
They came to a larger–than–usual opening in the side wall. Inside it there were rows and rows and rows of metal spheres some ten feet in diameter. There must have been hundreds of them. Beside the door there was a tiny shelf, with a tinier box fastened to it. A long way farther, they came to what had appeared to be the end of this corridor. But it did not end. It slanted upward and turned and they found themselves in the same corridor on a different level, headed back in the direction from which they had come. Their footsteps echoed hollowly in the still–enormous emptiness. There were other closed doors. Burke tried some. Holmes tried others. They did not open. Keller moved raptly, gazing at this and that.
Everything was strange, but not strange enough to be frightening. One could have believed this place the work of men, except that this was beyond the ability of men to make. There must be miles of vacant rooms carved out of solid rock. They came upon some hundreds of yards of doorways, and in every room on which they opened, there were metal frames about the walls. Holmes said suddenly, "If men had built this place, those could be bunks."
They came to another place where there was dust, and a group of six huge rooms communicating not only with the corridor but with each other. They found hollow metal things like cook pans. They found a hollow small object which could have been a drinking vessel. It was broken. It was of a size suitable for men.
"If men built this," said Holmes again, "these could be mess–halls. But I agree with Sandy that there should be signs."
Yet another closed door. It resisted their efforts to open it, just like the others. Keller put out his hand and thoughtfully touched the stone beside it. He looked astonished.
"What?" asked Burke. He touched the stone as Keller had. It was bitterly, bitterly cold. "The air's warm and the stone's cold! What's this?"
Keller wetted the tip of his finger and rubbed it on the rocky side wall. Instantly, frost appeared. But the air remained warm.
The gallery turned again, and again rose. The third–level passageway was shorter; barely half a mile in length. Here they passed door after door, all open, with each compartment containing a huge and somehow malevolent shape of metal. And beside each doorway there was a little shelf with a small box fastened to it.
"These," said Holmes, "could be guns, if there were any way for them to shoot anything. Just by the look of them I'd say they were weapons."
Burke said abruptly, "Keller, the stone being freezing cold while the air's warm means that this place has been heated up lately. Heat's been poured into it. Within hours!"
Keller considered. Then he shook his head.
"Not heat. Warmed air."
Burke went scowling onward. He followed, actually, the only route that was open. Other ways were cut off by doors which refused to open. Sandy, beside him, noted the floor. It was stone like the walls and ceiling. But it was worn. There were slight inequalities in it, beginning a foot or so from the walls. Sandy envisioned thousands of feet moving about these resonant corridors for hundreds or thousands of years in order to wear away the solid stone in this fashion. She felt age about her—incredible age reaching back to time past imagining, while the occupants of this hollow world swarmed about its interior. Doing what?
Burke considered other things. There were the ten–foot metal spheres, ranged by hundreds in what might be a magazine below. There were the squat and ugly metal monsters which seemed definitely menacing to somebody or something. There were the metal frameworks like bunks. There was no rust, here, which could be accounted for if Keller happened to be right and warmed air had been released lately in corridors which before—for ten thousand years or more—had contained only the vacuum of space. And there were those rooms which could be mess–halls.
These items were subject matter for thought. But if what they hinted at was true, there must be other specialized compartments elsewhere. There must be storerooms for food for those who managed the guns—if they were guns—and the spheres, and lived in the bunk–rooms and ate in the mess–halls. There'd be storerooms for equipment and supplies of all sorts. And again, if Keller were right about the air, there must be enormous pressure–tanks which had held the asteroid's atmosphere under high pressure for millennia, only to warm it and release it within the hour so that those who came by ship could use it.
An old phrase occurred to Burke. "A mystery wrapped in an enigma." It applied to these discoveries. Plainly the release of air had been done without the command of any living creature. There could be none here! As plainly, the signals from space had been begun without the interposition of life. The transmitter which still senselessly flung its message to Earth was a robot. The operation of the ship–lock, the warming of air, the lighting of the ship–lock and the corridors—all had been accomplished by machinery, obeying orders given to the transmitter first by some unguessable stimulus.