It took hours to establish it without the mention of a single word included in the lengthy key. The ship reached four hundred miles a second, turned about, and began to cut down its speed again.
Pam spoke from beside an electric stove, "Dinner's ready! Come and get it!"
They dined; Sandy weary, Burke absorbed and inevitably worried, Holmes placid and amiable, and Keller beaming and interested in all that went on, which was practically nothing.
They did not see the stars direct, because television cameras were preferable to portholes. Earth had become very small, and as it swung ever more nearly into a direct line between the ship and the sun, night filled more of its disk until only a hairline of sunshine showed at one edge. The microwave receivers ceased to mutter. The working astronomers on Earth who'd sent a message to M-387 were suddenly relieved of their disgrace and set to work again to equip the West Virginia radar telescope for continuous communication with Burke's ship. Other technicians began to prepare multiple receptors to pick up the ship's signals from hitherto unprecedented distances for human two-way communication.
And on Earth an official statement went out from high authority. It announced that a hurriedly completed American ship was on the way to M-387 to investigate the signals from space. It announced that measures long in preparation were now in use, and that an invincible fleet of spacecraft would be completed in months, whereas they had not been hoped for for another generation. An unexpected breakthrough had made it possible to advance the science of space travel by many decades, and a fleet to explore all the planets as well as M-387 was already under construction. It was almost true that they were. The blueprints of Burke's ship had been flown to Washington from the plant, and an enormous number of replicas of the egg-shaped vessel were ordered to be begun immediately, even before the theory of the drive was understood.
There was one minor hitch. A legal-minded official protested that Congressional appropriations had been for rocket-driven spaceships only, and the money appropriated could not be used for other than rockets. An executive order settled the matter. Then theorists began to object to the principle of the drive. It contradicted well-established scientific beliefs. It could not work.
It did, but there was violent opposition to the fact.
Publicly, of course, the shock of such an about-face by the national government was extreme. But newspapers flashed new headlines. "U.S. SHIP SPEEDING TO QUERY ALIENS!" Lesser heads announced, "Critical Velocity Exceeded! Russian Probe Already Passed!" The last was not quite true. The Russian manned probe had started out ten days before. Burke hadn't overtaken it yet.
Broadcasters issued special bulletins, and two networks canceled top evening programs to schedule interviews with prominent scientists who'd had nothing whatever to do with what Burke had managed to achieve.
In Europe, obviously, the political effect was stupendous. Russia was reduced to impassioned claims that the ship had been built from Russian plans, using Russian discoveries, which had been stolen by imperialistic secret agents. And the heads of the Russian spy system were disgraced for not having, in fact, stolen the plans and discoveries from the Americans. All other operatives received threats of what would happen to them if they didn't repair that omission. These threats so scared half a dozen operatives that they defected and told all they knew, thereby wrecking the Russian spy system for the time being.
Essentially, however, the recovery of confidence in America was as extravagant as the previous unhappy desire to hear no more about space. Burke, Holmes, Keller, Sandy and Pam became national heroes and heroines within eighteen hours after guided missiles had failed to shoot them down. The only criticism came from a highly conservative clergyman who hoped that other young girls would not imitate Sandy's and Pam's disregard of convention and maintained that a married woman should have gone along to chaperon them.
The atmosphere in the ship, however, was that of respectability carried to the point where things were dull. The lower compartment of the ship, being smaller, was inevitably appropriated by Sandy and Pam. They retired when the ship was twenty hours out from Earth. Each of them had prepared for stowing away by wearing extra garments in layers.
"Funny," said Pam, yawning as they made ready to turn in, "I thought it was going to be exciting. But it's just like a rather full day at the office."
"Which," said Sandy, "I'm quite used to."
"I do think you ought to have barged in when they designed the ship, Sandy. There's not one mirror in it!"
In the upper compartment Keller took his place in the control-chair and took a trick of duty. It consisted solely of looking at the instruments and listening to the beeping noises which came from remoteness every two seconds, and the still completely cryptic broadcasts which came every seventy-nine minutes. It wasn't exciting. There was nothing to be excited about. But somebody had to be on watch.
On the second day out, Washington was ready to use the new code. The West Virginia radar bowl was powered to handle communications again. Sandy painstakingly took down the gibberish that came in and decoded it. From then on she worked at the coding and transmission of messages and the reception and decoding of others. Presently Pam relieved her at the job. Pam tended to be bored because Holmes was as much absorbed in the business of keeping anything from happening as was Burke.
The messages were almost entirely requests for, and answers to requests for, details about the ship plans. The United States had not yet completed a duplicate drive-shaft. Machinists labored to reproduce the cores, which would then have to be wound in the complicated fashion the plans described. But it was an unhappy experience for the scientific minds assigned to duplicate Burke's ship. No woman ever followed a recipe without making some change. Very few physicists can duplicate another's apparatus without itching to change it. There were six copies of the drive under construction at the same time, at the beginning. Four were made by skeptics, who adhered to the original plans with strict accuracy. They were sure they'd prove Burke wrong. Two were "improved" in the making. The four, when finished, worked beautifully. The two doctored versions did not. But still there was fretful discussion of the theory of the drive. It seemed flatly to contradict Newton's law that every action has a reaction of equal moment and opposite sign—a law at least as firmly founded as the law of the conservation of energy. But that had lately been revised into the law of the conservation of energy and matter, which now was gospel. Burke's theory required the Newtonian law to be restated to read "every action of a given force has a reaction of the same force, of the same moment," and so on. When the reaction of one force is converted into another force, the results can be interesting. In fact, one can have a space-drive. But there was bitter resistance to the idea. It was demanded that Burke justify his views in a more reasonable way than by mere demonstration that they worked.
After a time, Burke gave up trying to explain things. And when one and then another duplicate drive worked, the argument ceased. But eminent physicists still had a resentful feeling that Burke was cheating on them somehow.
Then for days nothing happened. One of the three men in the ship always stayed in the control-chair where he could check the ship's course against the homing signals from the asteroid. He might have to correct it by the fraction of a hair, or swing ship and put on more drive if the radar should show celestial debris in the spaceship's path. Every so many hours the ship had to be swung about so that instead of accelerating she decelerated, or instead of decelerating gained fresh speed. But that was all.
On the fifth day there was the flash of a meteor on the radar. On the seventh day an object which could have been the second or third unmanned Russian probe showed briefly at the very edge of the radar screens. In essence, however, the journey was pure tedium. Burke wearied of making sure that his work was good, though he congratulated himself that nothing did happen to break the monotony. Holmes admitted that he was disappointed. He'd wanted to make the journey because he'd sailed in everything but a spaceship. But there was no fun in it. Keller alone seemed comfortably absorbed. He prepared daily lists of instrument-readings to be sent back to Earth. They would be of enormous importance to science-minded people. They were not of interest to Sandy.
Even when she talked to Burke, it was necessarily impersonal. There could be no privacy which was not ostentatious. The two girls used the lower compartment, the three men the upper and larger one. For Sandy to talk privately with Burke, she'd have had to go to the small bottom section of the ship. Holmes and Pam faced the same situation. It was uncomfortable. So they developed a perfectly pleasant habit of talking exclusively of things everybody could talk about. It did not bother Keller, who would hardly average a dozen words in twenty-four hours, but Sandy muttered to herself when she and Pam retired for what was a ship-night's rest.
When they went past the orbit of Mars, agitated instructions came out from Earth. The asteroid belts began beyond Mars. Elaborate directions came. The ship was tracked by radar telescopes all around the world, direction-finding on its transmission. Croydon kept track. American radar bowls picked up the ship's voice. South American and Hawaiian and Japanese and Siberian radar telescopes determined the ship's position every time a set of code symbols reached Earth from the ship. Of course, there were also the beepings and the seventy-nine-minute-spaced identical broadcasts from farther out from the sun.
Somebody got a brilliant idea and authority to try it. An interview for broadcast on Earth was sought with somebody on the ship. It was then a hundred thirty million miles from Earth, and ninety-two million more from the sun. Largely out of boredom Sandy agreed to answer questions. But at the speed of light it required eleven minutes to reach her from Earth, and as long for her reply to be received. It did not make for liveliness, so she spoke curtly for five minutes and stopped. She talked at random about housekeeping in space. Without knowing it, she was praised for her domesticity in many pulpits the following Sunday, and eight hundred ninety-two proposals of marriage piled up in mail addressed to her in care of the United States government. Twelve were in Russian.
But nothing really exciting happened aboard the spaceship. It was Burke's guess that they could go directly through the asteroid belt along the plane of the ecliptic, and not get nearer than ten thousand miles to any bit of shattered stone or metal in orbit out there. He was almost right. There was only one occasion when his optimism came into doubt.
It was on the ninth day out from Earth. Experimentally, the ship coasted on attained momentum, using no drive. There was, then, no substitute for gravity and everyone and everything in the ship was weightless. The power obtainable from the sun as heat had dwindled to one-ninth of that at the Earth's distance. But what was received could be stored, and was. Meanwhile the ship plunged onward at very nearly four hundred miles per second. Burke, Keller, and Holmes together labored over a self-contained diving suit which they hoped could be used as a space suit in dire emergency and for brief periods. They wanted to get the feel of using it with internal pressure and weightlessness as conditions. Sandy sat at the transmitter, working at code which by now she heartily loathed. Pam sat in the control-chair, watching the instruments.
There was a buzz. Burke snapped his head around to see the radar screen. A line of light appeared on it. It aimed directly at the center of the screen, which meant that whatever had been picked up was on a collision course with the ship. Burke plunged toward the control-chair to take over. But he'd forgotten the condition of no-gravity. He went floating off in mid-air, far wide of the chair.
He barked orders to Pam, who was least qualified of anybody aboard to meet an emergency of this sort. She panicked. She did nothing. Holmes took precious seconds to drag himself to the controls by what hand-holds could be had. The glowing white line on the radar screen lengthened swiftly. It neared the center. It reached the center. Burke and Holmes froze.
There was a curious flashing change in a vision-screen. An image flashed into view. It was a jagged, tortured, irregularly-shaped mass of stone or metal, distorted in its representation by the speed at which it passed the television lens. It was perhaps a hundred yards in diameter. It could never have been seen from Earth. It might circle the sun in its lonely orbit for a hundred million years and never be seen again.
It went away to nothing. It had missed by yards or fathoms, and Burke found himself sweating profusely. Holmes was deathly white. Keller very carefully took a deep breath, swallowed, and went back to his work on the diving-suit-qua-space-suit. Sandy hadn't noticed anything at all. But Pam burst into abrupt, belated tears, and Holmes comforted her clumsily. She was bitterly ashamed that she'd done nothing to meet the emergency which came while she was at the control-board, and which was the only emergency they'd encountered since the ship's departure from Earth.
After that, they put on the drive and used reserve fuel. It was necessary to check their speed, anyhow. They were very near the source of the beeping signal they'd steered by for so long. The directional receiver pointed to it had long since been turned down to its lowest possible volume, and still the beepings were loud.
On the eleventh day after their take-off, they sighted Asteroid M-387. They had traveled two hundred seventy million miles at an averaged-out speed of very close to three hundred miles per second. Despite muting, the beepings from the loud-speakers were monstrous noises.
"Try a call, Holmes," said Burke. "But they ought to know we're here."
He felt strange. He'd brought the ship to a stop about four or five miles from M-387. The asteroid was a mass of dark stuff with white outcroppings at one place and another. The ship seemed to edge itself toward it. The floating mass of stone and metal had no particular shape. It was longer than it was wide, but its form fitted no description. A mountain which had been torn from solidity with its roots of stone attached might look like Schull's Object as it turned slowly against a background of myriads of unblinking stars.
There was no change in the beeping that came from the singular thing. It did rotate, but so slowly that one had to watch for long minutes to be sure of it. There was no outward sign of any reaction to the ship's presence. Holmes took the microphone.
"Hello! Hello!" he said absurdly. "We have come from Earth to find out what you want."
No answer. No change in the beeping calls. The asteroid turned with enormous deliberation.
Sandy said suddenly, "Look there! A stick! No, it's a mast! See, where the patch of white is?"
Burke very, very gingerly drew closer to the monstrous thing which hung in space. It was true. There was a mast of some sort sticking up out of white stone. The direction-indicators pointed to it. The beeping stopped and a broadcast began. It was the standard broadcast Earth heard every seventy-nine minutes.
There was no reply to Holmes' call. There was no indication that the ship's arrival had been noted. On Earth the ignoring of human broadcasts to M-387 had seemed arrogance, indifference, a superior and menacing contempt for man and all his works; somehow, here the effect was different. This irregular mass was a fragment of something that once had been much greater. It suddenly ceased to seem menacing because it seemed oblivious. It acted blindly, by rote, like some mechanism set to operate in a certain way and unable to act in any other.
It did not seem alive. It had signaled like a robot beacon. Now it felt like one. It was one.
"Look, coming around toward us," said Holmes very quietly. "There's something that looks like a tunnel. It's not a crevasse. It was cut."
Burke nodded.
"Yes," he said thoughtfully. "I think we'll explore it. But I don't really expect we'll find any life here. There's nothing outside to see but a single metal mast. We've got some signal lights on our hull. If we're careful—"
No one objected. The appearance of the asteroid was utterly disappointing. Its lifelessness and its obliviousness to their coming and their calls were worse than disappointing. There was nothing to be seen but a metal stick from which signals went out to nowhere.
Burke jockeyed the little ship to the tunnel-mouth. It was fully a hundred feet in diameter. He turned on the ship's signal lights. Gently, cautiously, he worked down the very center of the very large bore.
It was perfectly straight. They went in for what seemed an indefinite distance. Presently the signal lights showed that the wall was smoothed. The bore grew smaller still. They went on and on.
Suddenly Keller grunted. He pointed to one of the six television screens which aimed out the length of the tunnel and showed the stars beyond.
Those stars were being blotted out. Something vast moved slowly and deliberately across the shaft they navigated. It closed the opening. Their retreat was blocked. The ship was shut in, in the center of a mountain of stone which floated perpetually in emptiness. Burke checked the ship's forward motion, judging their speed by the side walls shown by the ship's outside lights.
Very, very slowly, faint illumination appeared outside. In seconds they could see that the light came from long tubes of faint bluish light. The light changed. It grew stronger. It turned green and then yellowish and then became very bright, indeed.
Then nothing more took place. Nothing whatever. The five inside the ship waited more than an hour for some other development, but absolutely nothing happened.
There was a tiny shock; in a minute, trivial contact of the ship with something outside it. Drifting within the now brightly lighted bore, it had touched the wall. There was no force to the impact.
Keller made an interested noise. When eyes turned to him, he pointed to a dial. A needle on that dial pointed just past the figure "30." Burke grunted.
"The devil! We've been waiting for things to happen, and they already have! It's our move."
"According to that needle," agreed Holmes, "somebody has kindly put thirty point seven mercury inches of air-pressure around the ship outside. We can walk out and breathe, now."
"If," said Burke, "it's air. It could be something else. I'll have to check it."
He got out the self-contained diving apparatus that had been brought along to serve as a strictly temporary space suit.
"I'll try a cigarette-lighter. Maybe it will burn naturally. Maybe it will go out. It could make an explosion. But I doubt that very much."
"We'll hope," said Holmes, "that the lighter burns."
Burke climbed into the diving suit, which had been designed for amateurs of undersea fishing to use in chilly waters. On Earth it would have been intolerably heavy, for a man moving about out of the ocean. But there was no weight here. If M-387 had a gravitational field at all, which in theory it had to have, it would be on the order of millionths of the pull of Earth.
Keller sat in the control-chair, watching the instruments and the outside television screens which showed the bore now reduced to fifty feet. Somehow the more distant parts of the tunnel looked hazy, as if there were a slight mist in whatever gas had been released in it. Sandy watched Burke pull on the helmet and close the face-plate. She grasped a hand-hold, her knuckles turning white. Pam nestled comfortably in a corner of the ceiling of the control-room. Holmes frowned as Burke went into the air-lock and closed the inner door.
His voice came immediately out of a speaker at the control-desk.
"I'm breathing canned air from the suit," he said curtly.
There were scrapings. The outer lock-door made noises. There was what seemed to be a horribly long wait. Then they heard Burke's voice again.
"I've tried it," he reported. "The lighter burns when it's next to the slightly opened door. I'm opening wide now."
More noises from the air-lock.
"It still burns. Repeat. The lighter burns all right. The tunnel is filled with air. I'm going to crack my face-plate and see how it smells."
Silence, while Sandy went white. But a moment later Burke said crisply, "It smells all right. It's lifeless and stuffy, but there's nothing in it with an odor. Hold on—I hear something!"
A long minute, while the little ship floated eerily almost in contact with the walls about it. It turned slowly. Then there came brisk, brief fluting noises. They were familiar in kind. But this was a short message, of some fifteen or twenty seconds length, no more. It ended, was repeated, ended, was repeated, and went on with an effect of mechanical and parrot-like repetition.
"It's good air," reported Burke. "I'm breathing normally. But it might have been stored for ages. It's stale. Do you hear what I do?"
"Yes," said Sandy in a whisper to the control-room. "It's a call. It's telling us to do something. Come back inside, Joe!"
They heard the outer air-lock door closing and its locking-dogs engaging. The fluting noises ceased to be audible. The inner door swung wide. Burke came into the control-room, his helmet face-plate open. He wriggled out of the diving suit.
"Something picked up the fact that we'd entered. It closed a door behind us. Then it turned on lights for us. Then it let air into the entrance-lock. Now it's telling us to do something."
The ship surged, ever so gently. Keller had turned on an infinitesimal trace of drive. The walls of the bore floated past on the television screens. There was mist in the air outside. It seemed to clear as the ship moved.
Keller made a gratified small sound. They could see the end of the tunnel. There was a platform there. Stairs went to it from the side of the bore. There was a door with rounded corners in the end wall. That wall was metal.
Keller carefully turned the ship until the stairway was in proper position for a landing, if there had been gravitation to make the stairs usable. Very, very gently, he lowered the ship upon the platform.
There was a singular tugging sensation which ceased, came again, ceased, and gradually built up to a perfectly normal feeling of weight. They stood upon the floor of the control-room with every physical sensation they'd felt during one-gravity acceleration on the way out here, and which they'd have felt if the ship were aground on Earth.
"Artificial gravity! Whoever made this knew something!" Burke said.
Pam swallowed and spoke with an apparent attempt at nonchalance.
"Now what do we do?"
"We—look for the people," said Sandy in a queer tone.
"There's nobody here, Sandy!" Burke said irritably. "Can't you see? There can't be anybody here! They'd have signaled us what to do if there had been! This is machinery working. We do something and it operates. But then it waits for us to do something else. It's like—like a self-service elevator!"
"We didn't come here for an elevator ride," said Sandy.
"I came to find out what's here," said Burke, "and why it's signaling to Earth. Holmes, you stay here with the girls and I'll take a look outside."
"I'd like to mention," said Holmes drily, "that we haven't a weapon on this ship. When they shot rockets at us back on Earth, we didn't have even a pea-shooter to shoot back with. We haven't now. I think the girls are as safe exploring as they are here. And besides, we'll all feel better if we're together."
"I'm going!" said Sandy defiantly.
Burke hesitated, then shrugged. He unlatched the devices which kept both doors to the air-lock from being open at the same time. It was not a completely cautious thing to do, but caution was impractical. The ship was imprisoned. It was incapable of defense. There was simply nothing sensible about precautions that couldn't prevent anything.
Burke threw open the outer lock door. One by one, the five of them climbed down to the platform so plainly designed for a ship of space—a small one—to land upon. Nothing happened. Their surroundings were completely uninformative. This landing-platform might have been built by any race on Earth or anywhere else, provided only that it used stairs.
"Here goes," said Burke.
He went to the door with rounded corners. There was something like a handle at one side, about waist-high. He put his hand to it, tugged and twisted, and the door gave. It was not rusty, but it badly needed lubrication. Burke pulled it wide and stared unbelievingly beyond.
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.
But why? Other mysteries aside, there had plainly been meticulous preparation for the welcoming of a ship from space. No, not welcoming. Acceptance of a ship from space. Somebody had been expected to respond to those plaintive fluting noises which went wailing through the solar system. Who were those waited-for visitors expected to be? What were they expected to do? For that matter, what was the purpose of the asteroid itself? What had it been built for? At some time or another it must have contained thousands of inhabitants. What were they here for? What became of them? And when the asteroid was left—abandoned—what conceivable situation was to trigger the transmitter to send out urgent calls, and then a directional guiding-signal the instant the call was answered? When Burke's ship came, the asteroid accepted it without question and carried out mechanical operations to make it possible for that ship's crew to roam at will through it. What activated this mechanism of so many eons ago?
The five newly-arrived humans, three men and two girls, trudged along the echoing gallery cut out of the asteroid's heart. Murmurous sounds accompanied them. Once they came to a place where a whispering-gallery effect existed. They heard their footsteps repeated loudly as if the asteroid inhabitants were approaching invisibly, but no one came.
"I don't like this!" Pam said uneasily.
Then her own voice mocked her, and she realized what it was, and giggled nervously. That also was repeated, and sounded like something which seemed to sneer at them. It was unpleasant.
They came to the end of the gallery. There was a stair leading upward. There was nowhere else to go, so Burke started up, Sandy close behind him, and Holmes and Pam behind them. Keller brought up the rear. They climbed, and small noises began to be audible.
They were fluting sounds. They grew louder as the party from Earth went up and up. They reached a landing, and here also there was a metal door with rounded corners. Through it and from beyond it came the piping notes that Burke had heard in his dream some hundreds of times and that lately had come to Earth from emptiness. The sounds seemed to pause and to begin again, and once more to pause. It was not possible to tell whether they came from one source, speaking pathetically, or from two sources in conversation.
Sandy went utterly white and her eyes fixed upon Burke. He was nearly as pale, himself. He stopped. Here and now there was no trace of ribbony-leaved trees or the smell of green things, but only air which was stuffy and lifeless as if it had been confined for centuries. And there was no sunset sky with two moons in it, but only carved and seamless stone. Yet there were the familiar fluting sounds....
Burke put his hand to the curiously-shaped handle of the door. It yielded. The door opened inward. Burke went in, his throat absurdly dry. Sandy followed him.
And again there was disappointment. Because there was no living creature here. The room was perhaps thirty feet long and as wide. There were many vision-screens in it, and some of them showed the stars outside with a precision of detail no earthly television could provide. The sun glowed as a small disk a third of its proper diameter. It was dimmer, too. The Milky Way showed clearly. And there were very many screens which showed utterly clear views of the surface of the asteroid, all broken, chaotic, riven rock and massy, unoxydized metal.
But there was no life. There were not even symbols of life. There were only machines. They noticed a large transparent disk some ten feet across. Specks of light glowed within its substance. Off at one side an angular metal arm held a small object very close to the disk's surface, a third of the way from its edge. It did not touch the disk, but under it and in the disk there was a little group of bright-red specks which quivered and wavered. They were placed in a strict mathematical arrangement which very, very slowly changed so that it would be hours before it had completed a rotation and had exactly the same appearance again.
The flutings came from a tall metal cone on the floor. Another machine nearby held a round plate out toward the cone. "There's nobody here," said Sandy in a strange voice. "What'll we do now, Joe?"
"This must be the transmitter," he murmured. "The sound-record for the broadcasts must be in here, somehow. It's possible that this plate is a sort of microphone—"
Keller, beaming, pointed to a round spot which quivered with an eerie luminescence. It glowed more brightly and dimmed according to the flutings. Burke said "The devil!" and the round spot flickered up very brightly for an instant.
"Yes," said Burke. "It's a mike. It's quite likely—" the round spot flared up and dimmed with the modulations of his voice—"it's quite likely that what I say goes into the broadcast to Earth."
The cone ceased to emit fluting noises. Burke said very steadily—and the spot flickered violently with the sounds—"I think I am transmitting to Earth. If so, this is Joe Burke. I announce the arrival of my ship at Asteroid M-387. The asteroid has been hollowed out and fitted with an air-lock which admitted our ship. It is a—a—"
He hesitated, and Holmes said curtly, "It's a fortress."
"Yes," said Burke heavily. "It's a fortress. There are weapons we haven't had time to examine. There are barracks for a garrison of thousands. But there is no one here. It has been deserted, but not abandoned, because the transmitter was set up to send out a call when some occasion arose. It seems to have arisen. There is a big plate here which may be a star map, with a scale on which light-years may be represented by inches. I don't know. There are certain bright-red specks on it. They are moving. There is a machine to watch those specks. Apparently it actuated the transmitter to make it call to all the solar system."
Keller suddenly put his finger to his lips. Burke nodded and said curtly, "I'll report further."
Keller flipped over an odd switch with something of a flourish—after which he looked embarrassed. The transmitter went dead.
"He's right," said Holmes. "Back home they know we're here, I suspect, and you've told enough to give them fits. I think we'd better be careful what we say in the clear."
Burke nodded again. "There'll be calls from Earth shortly and we can decide whether or not to use code then. Keller, can you trace the leads to this transmitter and find the receiver that picked up that West Virginia beam-signal and changed the first broadcast to the second? It should be as sensitive as this transmitter is powerful."
Keller nodded confidently.
"It'll take thirty-some minutes for that report of mine to reach Earth and an answer to get back," observed Burke, "if everything works perfectly and the proper side of Earth is turned this way. I think we can be sure there's nobody but us in the fortress."
His sensations were peculiar. It was exciting to have found a fortress in space, of course. It was the sort of thing that might have satisfied a really dedicated scientist completely. Burke realized the importance of the discovery, but it was an impersonal accomplishment. It did not mean, to Burke, that he'd carried out the purpose behind his coming here. This fortress was linked to a dream about a world with two moons in its sky and someone or something running breathlessly behind unearthly swaying foliage. But this place was not the place of that dream, nor did it fulfill it. Mystery remained, and frustration, and Burke was left in the state of mind of a savage who has found a treasure which means much to civilized men, but doesn't make him any happier because he doesn't want what civilized men can give him.
He grimaced and spoke without elation.
"Let's go back to the ship and get a code message ready for Earth."
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."
"What I don't understand," said Sandy, "is why nothing's labelled. Nothing's marked. Whoever built it must have known how to write, in some fashion. A civilized race has to have written records to stay civilized! But I haven't seen a symbol or a pointer or even a color used to give information."
She got out the papers on which she would code the reports as Burke and Holmes turned them over for transmission. She began to write out, carefully, the elaborate key to the coding. Almost reluctantly, Pam prepared to do the same with Holmes' narrative of what he'd seen.
But if enthusiasm was tempered in the ship, there was no such reserve in the United States. Burke's voice had cut into one of the space broadcasts which arrived every seventy-nine minutes. There had been the usual cryptic, plaintive piping noises, repeating for the thousandth time their meaningless message. Then a human voice said almost inaudibly, "... 'll we do now, Joe?" It was heard over an entire hemisphere, where satellite-tracking stations and radar telescopes listened to and recorded every broadcast from space.
It was a stupendous happening. Then Burke's voice came through the flutings. "This must be the transmitter. The sound-record for the broadcasts must be in here, somehow. It's quite possible that this plate is a sort of microphone...." A few seconds later he was heard to say, "The devil!" And later still he addressed himself directly to his listeners on Earth.
He'd spoken the words eighteen and a fraction minutes before they arrived, though they traveled at the speed of light. Broadcast and ecstatically reported in the United States, they touched off a popular reaction as widespread as that triggered by the beginning of the signals themselves. Broadcasters abandoned all other subject matter. Announcers with lovely diction stated the facts and then expanded them into gibbering nonsense. Man had reached M-387. Man had spoken to Earth across two hundred seventy million miles of emptiness. Man had taken possession of a fortress in space. Man now had an outpost, a stepping-stone toward the stars. Man had achieved.... Man had risen.... Man now took the first step toward his manifest destiny, which was to occupy and possess all the thousands of thousands of planets all the way to the galaxy's rim.
But this was in the United States. Elsewhere, rejoicing was much less, especially after a prominent American politician was reported to have said that America's leadership of Earth was not likely ever to be challenged again. A number of the smaller nations immediately protested in the United Nations. That august body was forced to put upon its agenda a full-scale discussion of U.S. space developments. Middle European nations charged that the purpose of America was to monopolize not only the practical means of traveling to other members of the solar system, but all natural and technical resources obtained by such journeyings. With a singular unanimity, the nations at the edge of the Russian bloc demanded that there should be equality of information on Earth. No nation should hold back scientific information. In fact, there was bitter denunciation of the use of code by the humans now on M-387. It was demanded that they answer in the clear all scientific inquiries made by any government—in the clear so everybody could eavesdrop.
In effect, the United States rejoiced in and boasted of the achievements of some of its citizens who, after escaping attack by American guided missiles, had found a stepping-stone toward the stars. But the rest of the world jealously demanded that the United States reap no benefit from the fact. International tension, in fact, rose to a new high.
And Burke and the others laboriously gathered this bit of information and discovered the lack of that. They found incredible devices whose purpose or workings they could not understand. They found every possible evidence of a civilization beside which that of Earth was intolerably backward. But the civilization had abandoned the asteroid.
By the second day the mass of indigestible information had become alarming. They could marvel, but they could not understand. And not to understand was intolerable. They could comprehend that there was a device with red sparks in it which had made another device send a fluting, plaintive call to all the solar system. Nothing else was understandable. The purpose of the call remained a mystery.
But the communicators hummed with messages from Earth. It seemed that every radar telescope upon the planet had been furnished with a transmitter and that every one bombarded the asteroid with a tight beam carrying arguments, offers, expostulations and threats.
"This ought to be funny," said Burke dourly. "But it isn't. All we know is that we've found a fortress which was built to defend a civilization about which we know nothing except that it isn't in the solar system. We know an alarm went off, to call the fortress' garrison back to duty, but the garrison didn't come. We did. We've some evidence that a fighting fleet or something similar is headed this way and that it intends to smash this fortress and may include Earth. You'd think that that sort of news would calm them down, on Earth!"
The microwave receiver was so jammed with messages that there was no communication at all. None could be understood when all arrived at once. Burke had to send a message to Earth in code, specifying a new and secret wavelength, before it became possible to have a two-way contact with Earth. But the messages continued to come out, every one clamoring for something else of benefit to itself alone.
In the beginning there was nothing at all, and then things were created, and the wonder of created things was very great. When men became, they marveled at the richness and the beauty about them, and their lives were filled with astonishment at the myriads of things in the air and on the earth and in the sea. For many centuries they were busy taking note of all the created things that were. They forgot that there was such a condition as emptiness.
But there were six people in a certain solar system who really knew what emptiness amounted to. Five of them were in a fortress which was an asteroid and a mystery. One was in a small, crude object which floated steadily out from Earth. This one's name was Nikolai. The rest of it does not matter. He had been born in a small village in the Urals, and as a little boy he played games with mud and reeds and sticks and dogs and other little boys. As a growing youth he dutifully stuffed his head with things out of books, and some seemed to him rational and marvelous, and some did not make much sense but were believed by everybody. And who was he to go against the wise comrades who ran the government and protected the people from wars and famines and the schemes of villainous capitalists?
As a young man he was considered promising. If he had been interested in such matters, he might have had a moderately successful career in politics, as politics was practised in his nation. But he liked things. Real things.
When he was a student in the university he kept a canary in his lodgings. He loved it very much. There was a girl, too, about whom he dreamed splendidly. But there was a need for school teachers in Bessarabia, and she went there to teach. She wept when she left him. After that Nikolai studied with something of desperation, trying to forget her because he could not have her.
He thought of such past events as he drifted outward from Earth. He was the passenger, he was the crew of the manned space-probe his government had prepared to go out and investigate strange signals coming from emptiness. He was a volunteer, of course. It was a great honor to be accepted, and for a while he'd almost forgotten the girl who was teaching school in Bessarabia. But that was a long time ago, now. At first he'd liked to remember the take-off, when brisk, matter-of-fact men tucked him in his acceleration-chair and left him, and he lay staring upward in dead silence—save for the ticking of an insanely emotionless clock—until there was a roar to end all roars and a shock to crush anything made of flesh and bones, and then a terrible, horrible feeling of weight that kept on and on until he lost consciousness.
He could remember all this, if he chose. He had a distinct recollection of coming back to life, and of struggling to send off the signal which would say that he had survived the take-off. There were telemetering devices which reported what information was desired about the bands and belts of deadly radiation which surrounded the planet Earth. But Nikolai reported by voice, because that was evidence that he had passed through those murderous places unharmed. And his probe went on and on outward, away from the Earth and the sun.
He received messages from Earth. Tinny voices assured him that his launching had gone well. His nation was proud of him. Enormous rewards awaited him on his return. Meanwhile—The tinny voices instructed him in what he was to say for them to record and broadcast to all the world in his honor.
He said it, with the Earth a small crescent-shaped bit of brightness behind him. He drifted on. The crescent which was Earth grew smaller and smaller as days went by. He took due care of the instruments of his space-vehicle. He made sure that the air apparatus behaved properly. He disposed of wastes. From time to time he reported, by voice, information which automatic devices had long since given in greater detail and with superior accuracy.
And he thought more and more about the girl—teaching school in Bessarabia—and his canary, which had died. Days went by. He was informed that it was time for him to make contact with a drone fuel-rocket sent on before him. He watched the instruments which would point out where it was.
He found it, and with small auxiliary rockets he made careful tiny blastings which guided his vehicle to contact with it. The complex machinery for refueling took effect. Presently he cast off the emptied drone, aimed very, very carefully and blasted outward once more. The shock was worse than that on Earth, and he knew nothing for a long, long time. He was horribly weak when he regained consciousness. He mentioned it in his reports. There was no comment on the fact in the replies he received from Earth.
He continued to float away from the sun. It became impossible to pick out Earth among the stars. The sun was smaller than he remembered. There was nothing to be seen anywhere but stars and more stars and the dwindling disk of the sun that used to rise and set but now remained stationary, shrinking.
So Nikolai came to know emptiness. There were points of light which were stars. They were illimitable distances away. In between was emptiness. He had no sensation of movement. Save that as days went by the sun grew smaller, there was no change in anything. All was emptiness. If his vehicle floated like this for ten thousand times ten thousand years, the stars would appear no nearer. If he got out and ran upon nothingness to get back to where he could see Earth again, he would have to run for centuries, and generations would die and nations fall before he caught the least glimmer of that thin crescent which was his home.
If he shouted, no man would ever hear, because emptiness does not carry sound. If he died, there was no earth into which his body could be lowered. If he lived, there was nowhere he could stand upright and breathe clean air and feel solidity beneath his feet. He had a destination, to be sure, but he did not really believe that he would ever reach it, nor did he imagine he would ever return. Now he dismissed it from his thoughts.
He found that he was feverish, and he mentioned it when the tinny voices talked urgently to him. He guessed, without emotion, that he had not passed through the deadly radiation-belts around Earth unburned. He had been assured that he would pass through them so swiftly that they would be quite harmless. Now he knew that this was a mistake. His body obeyed him only sluggishly. He was dying of deep-seated radiation burns. But he felt nothing.
Voices waked him to insist that he make contact with another fuel-drone. He exhausted himself as he dutifully obeyed commands. He was clumsy. He was feeble. But he managed a second refueling. And even as he performed the highly technical operation with seemingly detached and reluctant hands, he thought of a schoolteacher in Bessarabia.
Before he fired the new fuel which would send him onward at what would be more than escape velocity, he almost humorously—yet quite humorlessly—reviewed his life. He considered that he might have no later opportunity to do so. There were three things he had done which no man had done before him. He had loved a certain small canary, and he remembered it distinctly. He had loved a certain girl, and in his weakened and dying state he could see her much more clearly than the grubby interior of the space-probe. And the third thing—
He had to cast about in his mind to remember what it was. His hand poised upon the rocket-firing key, he debated. Ah, yes! The third thing was that he had learned what emptiness was.
He pressed the firing-key. And the space-probe spouted flames and went on. Before the fuel was exhausted it had reached a velocity so great that it would go on forever through interstellar space. It would never fall back toward the sun, not even after thousands of years.
The knowledge of emptiness possessed by the five in the asteroid was different. A totally empty room is intimidating. A vacant house is depressing. The two-mile-long asteroid, honeycombed with tunnels and corridors and galleries and rooms, was like a deserted city. Those who had left it had carefully stripped it of personal possessions, but they'd left weapons behind, ready to be manned and used. They'd left a warning device to call them. The recall device was proof that the danger had not been destroyed and might return. And the plaintive call through all the solar system proved that it was returning.
There was irony in the fact that Earth had panicked when it seemed that intelligent non-human beings signaled from space, and that shrill disputes for advantage began instantly Burke reported no living monsters at the signals' source. The fortress and its call meant more than the mere existence of aliens. It was proof that there were entities of space who needed to be fought. It proved the existence of fighting ships of space; of deadly war in emptiness; of creatures who crossed the void between star systems to conquer and to murder and destroy.
And such creatures were coming.
Burke ground his teeth. Earth had fusion bombs and rockets which could carry them for pitifully short distances on the cosmic scale. This fortress was incomparably more powerful than all of Earth's armament put together. A fleet which dared to attack it must feel itself stronger still. What could Earth do against a fleet which dared attack this asteroid?
And what could he and Holmes and Keller do against such a fleet, even with the fortress, when they did not yet understand a single one of its weapons?
Burke worked himself to exhaustion, trying to unravel even the simplest principles of the fortress' armament. There were globes which were, obviously, the long-range weapons of the garrison. They were stored in a launching-tube at the far back of the compartment. But Keller could not unravel the method of their control. There was no written matter in the fortress. None. A totally unknown language and an unfamiliar alphabet would prevent written matter from being useful, ordinarily, but in technical descriptions there are bound to be diagrams. Burke felt desperately that in even the most meaningless of scripts there would be diagrams which could be puzzled out. But there was nothing. The builders of the fortress could have been illiterate, for all the signs of writing that they'd left.
Keller continued to labor valiantly. But there was no clue to the operation of anything but the transmitter. That was understandable because one knew where the message went in, and where it came out for broadcast. With the apparatus before one, one could deduce how it operated. But no one could guess how weapons were controlled when he hadn't the least idea of what they did.
On the third night in the asteroid—the third night by ship-time, since there was neither day nor night in the great empty corridors of the fortress—Burke dreamed his dream again. It was perfectly familiar, from the trees with their trailing leaves, to the markings on the larger moon. He felt the anguished anxiety he'd so often known before. He grasped the hand-weapon and knew that he was ready to fight anything imaginable for the person he feared for. He heard small fluting sounds behind him, and then he knew that someone ran breathlessly behind the swaying foliage just ahead. He felt such relief and exultation that his heart seemed about to burst. He gave a great shout and bounded to meet her—
He waked in the small ship in the entrance tunnel. All was silent. All was still. The lights in the control-compartment of the ship were turned to dim. There was no sound anywhere. The opened air-lock doors, both inner and outer, let in a fan-shaped streak of brightness which lay on the floor.
Burke lay quiet, still wrought up by the vivid emotions of the dream.
He heard a stirring in the compartment below, occupied by Sandy and Pam. Someone came very quietly up the ladder-like stairway. Burke blinked in the semi-darkness. He saw that it was Sandy. She crossed the compartment to the air-lock. Very quietly, she closed the outer door and then the inner. She fastened them.
Burke said, sitting up, "Why'd you do that, Sandy?"
She started violently, and turned.
"Pam can't sleep," she said in a low tone. "She says the fortress is creepy. She feels that there's something hiding in it, something deadly and frightening. When you leave the air-lock open, she's afraid. So I closed it."
"Holmes and Keller are out," said Burke. "Keller's trying to trace down power-leads from the instrument-room to whatever power-source warms and lights everything. We can't lock him out."
Sandy obediently opened the air-lock doors again. She turned toward the ladder leading downward.
"Sandy," said Burke unhappily, "I know I'm acting like a fool."
"You're doing all right," said Sandy. She paused at the top of the ladder. "Finding this—" she waved her hand about her—"ought to put your name in the history books. Of course you'll be much disliked by people who intended to invent space travel themselves. But you're doing all right."
"I'm not thinking of that," said Burke. "I'm thinking of you. I was going to ask you to marry me. I didn't. If we live through this, will you?"
Sandy regarded him carefully in the dim light of the ship's interior, most of which came through the air-lock doors.
"There are some conditions," she said evenly. "I won't play second fiddle to an imaginary somebody behind a veil of dreamed-of leaves. I don't want to make conditions, Joe. But I couldn't stand your feeling that maybe in marrying me you'd give up your chance of finding her—whatever or whoever she is."
"But I wouldn't feel that way!" protested Burke.
"I'd believe you did," said Sandy. "And it would amount to the same thing. I think I made a mistake in coming along in the ship, Joe. If I weren't along you might have missed me. You might even—" she grimaced—"you might even have dreamed about me. But here I am. And I can't compete with somebody in a dream. I won't even try. I—I can't imagine marrying anybody else, but if I do get married I want to be the only girl my guy dreams about!"
She turned again to the ladder. Then said abruptly, "You didn't ask why Pam feels creepy, or where. There's a place up on the second gallery where there's a door that's still locked. Pam gets the shivers when she goes by it. I don't. The whole place is creepy, to me."
She went down the ladder. Minutes later Holmes and Keller arrived.
Holmes said curtly, "The machinery in the transmitter-room reached a change-point just now. Those red dots in that plastic plate apparently started the transmitter in the first place. When its calls were answered it changed the broadcast, adding a directional signal. Just before we started out from Earth the red sparks passed another place and changed the broadcast again. Now they've passed a third place. We were there when the machinery shifted all around on a signal from that thing which hovers close to the red sparks and watches them. The transmitter probably blasted out at four or five times its original volume. There must have been a hundred thousand kilowatts in it, at least. It looks serious. Whatever those red sparks represent must be close."
Keller nodded in agreement, frowning, then he and Holmes wearily prepared to turn in. But Burke was upset. He knew he wouldn't be able to sleep.
"Pam gets the creeps when she passes a certain locked door up on the second gallery. I never noticed it, but I'm going to get that door open. We got to look into every compartment of this thing! There's bound to be something informative somewhere! Close the air-lock behind me so Pam can sleep."
He went out. Behind him, Holmes looked at Keller.
"Funny!" he said drily. "We're all scared. I feel uneasy all the time, without knowing why. But if he's as scared as I am, why doesn't he worry about going places alone?"
The same question occurred to Burke. The atmosphere of the brightly lighted halls was ominous and secretive. A man alone in a vast empty building would feel queer even in broad daylight with sunshine and other humans to be seen out of any window. But in this monstrous complex of tunnels and rooms carved out of solid stone, with uncountable millions of miles of pure emptiness without, the feeling of loneliness was incredible. He reflected wryly that a dog would be a comforting companion to have on such a journey as his.
He went down the long gallery with doors on either side. Past the room with the piled metal ingots. Past the door through which one saw hundreds of ten-foot metal globes. Up a ramp. Past the rooms where something like bunks must once have stood against the walls. A long way along this corridor. Emptiness, emptiness, emptiness. Innumerable echoings of his footsteps on the stone.
Three times he stopped at doors that had swung shut, but none was fully closed. All yielded readily. Then he came to the door Sandy had spoken about. He worked the handle repeatedly. It was firmly shut. He kicked the door and with a loud click it swung open.
There were lights inside this room, as everywhere else they had explored. But it was nearly impossible to see any distance. This was an extremely long room, and it contained racks of metal which reached from floor to ceiling. Each rack was a series of shallow metal troughs, and in each trough there was a row of crumbly black metal cubes, very systematically arranged. Each side was about three inches square, and they were dull black, not glistening at all. They filled the racks completely. There were narrow aisles between the rows of racks, through which Burke could make his way easily enough, but which a more portly man might have found inconvenient.
He stared at a trough, and was stunned. He picked up one of the cubes, and immediately recognized the object in his hand. It was a dull-black, smudgy cube exactly like the one his uncle had brought back from the Cro-Magnon cave in France. He knew that if he dropped this object—found two hundred seventy million miles from the other one—it would split into thousands of tissue-thin, shiny pieces.
He did drop it. Deliberately. And it shattered into layers which lay like films of mica on the floor.
For no clearly understandable reason, Burke found that his flesh crawled. He had to force himself to stay in this room with so many thousands of the enigmatic cubes. There had been a cube of this kind on Earth. The one he'd known as a child had belonged to a Cro-Magnon tribesman ten thousand, twenty thousand, how many years ago? And it could only have come from this asteroid. Which meant—
Presently he made his way back to the spaceship. He carried one of the cubes, rather gingerly. He meant to show it to Sandy. But the implications were startling.
Members of the garrison of this fortress, thousands of years gone by, had visited Earth. One of them, doubtless, had carried that other cube. Why? When the garrison abandoned the asteroid they left these cubes behind. They left behind intricate machinery to call them back. They left squat machines and ten-foot globes which must be weapons. They left nothing that would be useful in the place to which they had removed. But they'd left these cubes, hundreds of thousands of them.
The cube, then, could be anything. It could be impersonal, like equipment for the fortress that would be useless elsewhere. The fortress' equipment was designed to deal out death. Were the cubes? No. Burke had owned one without damage. When that cube split into glistening, tissue-thin plates, no one was injured. To be sure, there was his dream. But the cube wasn't a weapon. Whatever else it might be, it was not dangerous.
He went into the spaceship and for no reason whatever firmly locked both air-lock doors. Holmes and Keller were asleep. There was no sound from the lower compartment occupied by Sandy and Pam.
Burke put the black object on the control-desk. The single cube on Earth had been meaningless. The museum which joyfully accepted Cro-Magnon artifacts from his uncle had dismissed it as of no importance. It was fit only to be given to an eleven-year-old boy. But a roomful of such cubes couldn't be without meaning!
He dismissed this newest mystery with an almost violent effort of his will. It was a mystery. Yet there was no intention to have the fortress seem a mystery to whoever answered its call to space. He could guess that the signals were notification of some emergency which needed to be met. The automatic apparatus of the ship-lock was set to aid those who came in response to the call. But everything presupposed that those who came would know why they came.
Burke didn't. The thing must be simple, an explanation not yet thought of. But there was nowhere to start to think about it! His recurrent dream? No. That was as mysterious as the rest.
Burke was very, very lonely and depressed. He could look for no help in solving the mystery. Earth was now past the point of conjunction with M-387, and moved nearly a million miles a day along its orbit, with nearly half of them away from the fortress. At the most hopeful estimate, it would be three months or later before an emergency space fleet of replicas of his own ship could lift off from Earth for here.
And Burke was reasonably sure that the red sparks would have reached the center of the disk in much less time than that. If it were in some fashion like a radar, making a map of the surroundings of the asteroid, the observer's place would be in the middle. In that event, whatever the red sparks represented would reach the fortress before more ships came out from Earth.