The scale of the picture was, of course, continually expanding. It was now many miles from side to side, and I felt like an airman looking down upon an unbroken cloud ceiling from an enormous height. For a moment a sense of vertigo seized me as I thought of the abyss into which I was gazing. I do not think that the world will ever seem quite solid to me again.
At a depth of nearly ten miles I stopped and looked at the Professor. There had been no alteration for some time, and I knew that the rock must now be compressed into a featureless, homogeneous mass. I did a quick mental calculation and shuddered as I realized that the pressure must be at least thirty tons to the square inch. The scanner was revolving very slowly now, for the feeble echoes were taking many seconds to struggle back from the depths.
"Well, Professor," I said, "I congratulate you. It's a wonderful achievement. But we seem to have reached the core now. I don't suppose there'll be any change from here to the center."
He smiled a little wryly. "Go on," he said. "You haven't finished yet."
There was something in his voice that puzzled and alarmed me. I looked at him intently for a moment; his features were just visible in the blue-green glow of the cathode ray tube.
"How far down can this thing go?" I asked, as the interminable descent started again.
"Fifteen miles," he said shortly. I wondered how he knew, for the last feature I had seen at all clearly was only eight miles down. But I continued the long fall through the rock, the scanner turning more and more slowly now, until it took almost five minutes to make a complete revolution. Behind me I could hear the Professor breathing heavily, and once the back of my chair gave a crack as his fingers gripped it.
Then, suddenly, very faint markings began to reappear on the screen. I leaned forward eagerly, wondering if this was the first glimpse of the world's iron core. With agonizing slowness the scanner turned through a right angle, then another. And then—
I leaped suddenly out of my chair, cried "My God!" and turned to face the Professor. Only once before in my life had I received such an intellectual shock—fifteen years ago, when I had accidentally turned on the radio and heard of the fall of the first atomic bomb. That had been unexpected, but this was inconceivable. For on the screen had appeared a grid of faint lines, crossing and recrossing to form a perfectly symmetrical lattice.
I know that I said nothing for many minutes, for the scanner made a complete revolution while I stood frozen with surprise. Then the Professor spoke in a soft, unnaturally calm voice.
"I wanted you to see it for yourself before I said anything. That picture is now thirty miles in diameter, and those squares are two or three miles on a side. You'll notice that the vertical lines converge and the horizontal ones are bent into arcs. We're looking at part of an enormous structure of concentric rings; the center must lie many miles to the north, probably in the region of Cambridge. How much further it extends in the other direction we can only guess."
"But what is it, for heaven's sake?"
"Well, it's clearly artificial."
"That's ridiculous! Fifteen miles down!"
The Professor pointed to the screen again. "God knows I've done my best," he said, "but I can't convince myself that Nature could make anything like that."
I had nothing to say, and presently he continued: "I discovered it three days ago, when I was trying to find the maximum range of the equipment. I can go deeper than this, and I rather think that the structure we can see is so dense that it won't transmit my radiations any further.
"I've tried a dozen theories, but in the end I keep returning to one. We know that the pressure down there must be eight or nine thousand atmospheres, and the temperature must be high enough to melt rock. But normal matter is still almost empty space. Suppose that there is life down there—not organic life, of course, but life based on partially condensed matter, matter in which the electron shells are few or altogether missing. Do you see what I mean? To such creatures, even the rock fifteen miles down would offer no more resistance than water—and we and all our world would be as tenuous as ghosts,"
"Then that thing we can see——"
"Is a city, or its equivalent. You've seen its size, so you can judge for yourself the civilization that must have built it. All the world we know—our oceans and continents and mountains—is nothing more than a film of mist surrounding something beyond our comprehension."
Neither of us said anything for a while. I remember feeling a foolish surprise at being one of the first men in the world to learn the appalling truth; for somehow I never doubted that it was the truth. And I wondered how the rest of humanity would react when the revelation came.
Presently I broke into the silence. "If you're right," I said, "why have they—whatever they are—never made contact with us?"
The Professor looked at me rather pityingly. "We think we're good engineers," he said, "but how could we reach them? Besides, I'm not at all sure that there haven't been contacts. Think of all the underground creatures and the mythology—trolls and cobalds and the rest. No, it's quite impossible—I take it back. Still, the idea is rather suggestive."
All the while the pattern on the screen had never changed: the dim network still glowed there, challenging our sanity. I tried to imagine streets and buildings and the creatures going among them, creatures who could make their way through the incandescent rock as a fish swims through water. It was fantastic ... and then I remembered the incredibly narrow range of temperatures and pressures under which the human race exists. We, not they, were the freaks, for almost all the matter in the universe is at temperatures of thousands or even millions of degrees.
"Well," I said lamely, "what do we do now?"
The Professor leaned forward eagerly. "First we must learn a great deal more, and we must keep this an absolute secret until we are sure of the facts. Can you imagine the panic there would be if this information leaked out? Of course, the truth's inevitable sooner or later, but we may be able to break it slowly.
"You'll realize that the geological surveying side of my work is now utterly unimportant. The first thing we have to do is to build a chain of stations to find the extent of the structure. I visualize them at ten-mile intervals toward the north, but I'd like to build the first one somewhere in South London to see how extensive the thing is. The whole job will have to be kept as secret as the building of the first radar chain in the late thirties.
"At the same time, I'm going to push up my transmitter power again. I hope to be able to beam the output much more narrowly, and so greatly increase the energy concentration. But this will involve all sorts of mechanical difficulties, and I'll need more assistance."
I promised to do my utmost to get further aid, and the Professor hopes that you will soon be able to visit his laboratory yourself. In the meantime I am attaching a photograph of the vision screen, which although not as clear as the original will, I hope, prove beyond doubt that our observations are not mistaken.
I am well aware that our grant to the Interplanetary Society has brought us dangerously near the total estimate for the year, but surely even the crossing of space is less important than the immediate investigation of this discovery which may have the most profound effects on the philosophy and the future of the whole human race.
I sat back and looked at Karn. There was much in the document I had not understood, but the main outlines were clear enough.
"Yes," I said, "this is it! Where's that photograph?"
He handed it over. The quality was poor, for it had been copied many times before reaching us. But the pattern was unmistakable and I recognized it at once.
"They were good scientists," I said admiringly. "That's Callastheon, all right. So we've found the truth at last, even if it has taken us three hundred years to do it."
"Is that surprising," asked Karn, "when you consider the mountain of stuff we've had to translate and the difficulty of copying it before it evaporates? "
I sat in silence for a while, thinking of the st
range race whose relics we were examining. Only once—never again! —had I gone up the great vent our engineers had opened into the Shadow World. It had been a frightening and unforgettable experience. The multiple layers of my pressure suit had made movement very difficult, and despite their insulation I could sense the unbelievable cold that was all around me.
"What a pity it was," I mused, "that our emergence destroyed them so completely. They were a clever race, and we might have learned a lot from them."
"I don't think we can be blamed," said Karn. "We never really believed that anything could exist under those awful conditions of near-vacuum, and almost absolute zero. It couldn't be helped."
I did not agree. "I think it proves that they were the more intelligent race. After all, they discovered us first. Everyone laughed at my grandfather when he said that the radiation he'd detected from the Shadow World must be artificial."
Karn ran one of his tentacles over the manuscript.
"We've certainly discovered the cause of that radiation," he said. "Notice the date—it's just a year before your grandfather's discovery. The Professor must have got his grant all right!" He laughed unpleasantly. "It must have given him a shock when he saw us coming up to the surface, right underneath him."
I scarcely heard his words, for a most uncomfortable feeling had suddenly come over me. I thought of the thousands of miles of rock lying below the great city of Callastheon, growing hotter and denser all the way to the Earth's unknown core. And so I turned to Karn.
"That isn't very funny," I said quietly. "It may be our turn next."
THE AWAKENING
Marlan was bored, with the ultimate boredom that only Utopia can supply. He stood before the great window and stared down at the scudding clouds, driven by the gale that was racing past the foothills of the city. Sometimes, through a rent in the billowing white blanket, he could catch a glimpse of lakes and forests and the winding ribbon of the river that flowed through the empty land he now so seldom troubled to visit. Twenty miles away to the west, rainbow-hued in the sunlight, the upper peaks of the artificial mountain that was City Nine floated above the clouds, a dream island adrift in the cold wastes of the stratosphere. Marlan wondered how many of its inhabitants were staring listlessly across at him, equally dissatisfied with life.
There was, of course, one way of escape, and many had chosen it. But that was so obvious, and Marlan avoided the obvious above all things. Besides, while there was still a chance that life might yet hold some new experience, he would not pass through the door that led to oblivion.
Out of the mist that lay beneath him, something bright and flaming burst through the clouds and dwindled swiftly toward the deep blue of the zenith. With lack-lustre eyes, Marlan watched the ascending ship: once—how long ago!—the sight would have lifted his heart. Once he too had gone on such journeys, following the road along which Man had found his greatest adventures. But now on the twelve planets and the fifty moons there was nothing one could not find on Earth. Perhaps, if only the stars could have been reached, humanity might have avoided the cul-de-sac in which it was now trapped; there would still have remained endless vistas of exploration and discovery. But the spirit of mankind had quailed before the awful immensities of interstellar space. Man had reached the planets while he was still young, but the stars had remained forever beyond his grasp.
And yet—Marlan stiffened at the thought and stared along the twisting vapor-trail that marked the path of the departed ship—if Space had defeated him, there was still another conquest to be attempted. For a long time he stood in silent thought, while, far beneath, the storm's ragged hem slowly unveiled the buttresses and ramparts of the city, and below those, the forgotten fields and forests which had once been Man's only home.
The idea appealed to Sandrak's scientific ingenuity; it presented him with interesting technical problems which would keep him occupied for a year or two. That would give Marlan ample time to wind up his affairs, or, if necessary, to change his mind.
If Marlan felt any last-minute hesitations, he was too proud to show it as he said good-by to his friends. They had watched his plans with morbid curiosity, convinced that he was indulging in some unusually elaborate form of euthanasia. As the door of the little spaceship closed behind Marlan, they walked slowly away to resume the pattern of their aimless lives; and Roweena wept, but not for long.
While Marlan made his final preparations, the ship climbed on its automatic course, gaining speed until the Earth was a silver crescent, then a fading star lost against the greater glory of the sun. Rising upward from the plane in which the planets move, the ship drove steadily toward the stars until the sun itself had become no more than a blazing point of light. Then Marlan checked his outward speed, swinging the ship round into an orbit that made it the outermost of all the sun's children. Nothing would ever disturb it here; it would circle the sun for eternity, unless by some inconceivable chance it was captured by a wandering comet.
For the last time Marlan checked the instruments that Sandrak had built. Then he went to the innermost chamber and sealed the heavy metal door. When he opened it again, it would be to learn the secret of human destiny.
His mind was empty of all emotion as he lay on the thickly padded couch and waited for the machines to do their duty. He never heard the first whisper of gas through the vents; but consciousness went out like an ebbing tide.
Presently the air crept hissing from the little chamber, and its store of heat drained outward into the ultimate cold of space. Change and decay could never enter here; Marlan lay in a tomb that would outlast any that man had ever built on Earth, and might indeed outlast the Earth itself. Yet it was more than a tomb, for the machines it carried were biding their time, and every hundred years a circuit opened and closed, counting the centuries.
So Marlan slept, in the cold twilight beyond Pluto. He knew nothing of the life that ebbed and flowed upon Earth and its sister planets while the centuries lengthened into millennia, the millennia into eons. On the world that had once been Marlan's home, the mountains crumbled and were swept into the sea; the ice crawled down from the Poles as it had done so many times before and would do many times again. On the ocean beds the mountains of the future were built layer by layer from the falling silt, and presently rose into the light of day, and in a little while followed the forgotten Alps and Himalayas to their graves.
The sun had changed very little, all things considered, when the patient mechanism of Marlan's ship reawakened from their long sleep. The air hissed back into the chamber, the temperature slowly climbed from the verge of absolute zero to a level at which life might start again. Gently, the handling machines began the delicate series of tasks which should revitalize their master.
Yet he did not stir. During the long ages that had passed since Marlan began his sleep, something had failed among the circuits that should have awakened him. Indeed, the marvel was that so much had functioned correctly; for Marlan still eluded Death, though his servants would never recall him from his slumbers.
And now the wonderful ship remembered the commands it had been given so long ago. For a little while, as its multitudinous mechanisms slowly warmed to life, it floated inert with the feeble sunlight glinting on its walls. Then, ever more swiftly, it began to retrace the path along which it had traveled when the world was young. It did not check its speed until it was once more among the inner planets, its metal hull warming beneath the rays of the ancient unwearying sun. Here it began its search, in the temperate zone where the Earth had once circled; and here it presently found a planet it did not recognize.
The size was correct, but all else was wrong. Where were the seas that once had been Earth's greatest glory? Not even their empty beds were left: the dust of vanished continents had clogged them long ago. And where, above all, was the Moon? Somewhere in the forgotten past it had crept earthward and met its doom, for the planet was now girdled, as once only Saturn had been, by a vast, thin halo of circling dust.
 
; For a while the robot controls searched through their electronic memories as the ship considered the situation. Then it made its decision, if a machine could have shrugged its shoulders, it would have done so. Choosing a landing place at random, it fell gently down through the thin air and came to rest on a flat plain of eroded sandstone. It had brought Marlan home; there was nothing more that it could do. If there was still life on the Earth, sooner or later it would find him.
And here, indeed, those who were now masters of Earth presently came upon Marlan's ship. Their memories were long, and the tarnished metal ovoid lying upon the sandstone was not wholly strange to them. They conferred among each other with as much excitement as their natures allowed and, using their own strange tools, began to break through the stubborn walls until they reached the chamber where Marlan slept.
In their way, they were very wise, for they could understand the purpose of Marlan's machines and could tell where they had failed in their duty. In a little while the scientists had made what repairs were necessary, though they were none too hopeful of success. The best that they could expect was that Marlan's mind might be brought, if only for a little while, back to the borders of consciousness before Time exacted its long-deferred revenge.
The light came creeping back into Marlan's brain with the slowness of a winter dawn. For ages he lay on the frontiers of self-awareness, knowing that he existed but not knowing who he was or whence he had come. Then fragments of memory returned, and fitted one by one into the intricate jigsaw of personality, until at last Marlan knew that he was—Marlan. Despite his weakness, the knowledge of success brought him a deep and burning sense of satisfaction. The curiosity that had driven him down the ages when his fellows had chosen the blissful sleep of euthanasia would soon be rewarded: he would know what manner of men had inherited the earth.