It seemed to change before my eyes as I sliced down through the tenuous outer envelope with its trailing arms, and approached the denser core. "Denser," of course, was a purely relative word; by terrestrial standards even its most closely packed regions were still a fairly good vacuum. I had almost reached the limit of my frequency band, and could shorten the wave length no farther, when I noticed the curious, tight little echo not far from the center of the screen.

  It was oval, and much more sharp-edged than the knots of gas we had watched adrift in the cloud's fiery streams. Even

  in that first glimpse, I knew that here was something very strange and outside all previous records of solar phenomena. I watched it for a dozen scans of the radar beam, then called my assistant away from the radio-spectrograph, with which he was analyzing the velocities of the swirling gas as it spun toward us.

  "Look, Don," I asked him, "have you ever seen anything like that?"

  "No," he answered after a careful examination. "What holds it together? It hasn't changed its shape for the last two minutes."

  "That's what puzzles me. Whatever it is it should have started to break up by now, with all that disturbance going on around it. But it seems as stable as ever."

  "How big would you say it is?"

  I switched on the calibration grid and took a quick reading.

  "It's about five hundred miles long, and half that in width."

  "Is this the largest picture you can get?"

  "I'm afraid so. We'll have to wait until it's closer before we can see what makes it tick."

  Don gave a nervous little laugh.

  "This is crazy," he said, "but do you know something? I feel as if I'm looking at an amoeba under a microscope."

  I did not answer; for, with what I can only describe as a sensation of intellectual vertigo, exactly the same thought had entered my mind.

  We forgot about the rest of the cloud, but luckily the automatic cameras kept up their work and no important observations were lost. From now on we had eyes only for that sharp-edged lens of gas that was growing minute by minute as it raced toward us. When it was no farther away than is the Moon from Earth, it began to show the first signs of its internal structure, revealing a curious mottled appearance that was never quite the same on two successive sweeps of the scanner.

  By now, half the Observatory staff had joined us in the radar room, yet there was complete silence as the oncoming

  enigma grew swiftly across the screen. It was coming straight toward us; in a few minutes it would hit Mercury somewhere in the center of the daylight side, and that would be the end of it—whatever it was. From the moment we obtained our first really detailed view until the screen became blank again could not have been more than five minutes; for every one of us, that five minutes will haunt us all our lives.

  We were looking at what seemed to be a translucent oval, its interior laced with a network of almost invisible lines. Where the lines crossed there appeared to be tiny, pulsing nodes of light; we could never be quite sure of their existence because the radar took almost a minute to paint the complete picture on the screen—and between each sweep the object moved several thousand miles. There was no doubt, however, that the network itself existed; the cameras settled any arguments about that.

  So strong was the impression that we were looking at a solid object that I took a few moments off from the radar screen and hastily focused one of the optical telescopes on the sky. Of course, there was nothing to be seen—no sign of anything silhouetted against the sun's pock-marked disk. This was a case where vision failed completely and only the electrical senses of the radar were of any use. The thing that was coming toward us out of the sun was as transparent as air—and far more tenuous.

  As those last moments ebbed away, I am quite sure that every one of us had reached the same conclusion—and was waiting for someone to say it first. What we were seeing was impossible, yet the evidence was there before our eyes. We were looking at life, where no life could exist. . . .

  The eruption had hurled the thing out of its normal environment, deep down in the flaming atmosphere of the sun. It was a miracle that it had survived its journey through space; already it must be dying, as the forces that controlled its huge, invisible body lost their hold over the electrified gas which was the only substance it possessed.

  Today, now that I have run through those films a hundred

  times, the idea no longer seems so strange to me. For what is life but organized energy? Does it matter what form that energy takes—whether it is chemical, as we know it on Earth, or purely electrical, as it seemed to be here? Only the pattern is important; the substance itself is of no significance. But at the time I did not think of this; I was conscious only of a vast and overwhelming wonder as I watched this creature of the sun live out the final moments of its existence.

  Was it intelligent? Could it understand the strange doom that had befallen it? There are a thousand such questions that may never be answered. It is hard to see how a creature born in the fires of the sun itself could know anything of the external Universe, or could even sense the existence of something as unutterably cold as rigid nongaseous matter. The living island that was falling upon us from space could never have conceived, however intelligent it might be, of the world it was so swiftly approaching.

  Now it filled our sky—and perhaps, in those last few seconds, it knew that something strange was ahead of it. It may have sensed the far-flung magnetic field of Mercury, or felt the tug of our little world's gravitational pull. For it had begun to change; the luminous lines that must have been what passed for its nervous system were clumping together in new patterns, and I would have given much to know their meaning. It may be that I was looking into the brain of a mindless beast in its last convulsion of fear—or of a godlike being making its peace with the Universe.

  Then the radar screen was empty, wiped clean during a single scan of the beam. The creature had fallen below our horizon, and was hidden from us now by the curve of the planet. Far out in the burning dayside of Mercury, in the inferno where only a dozen men have ever ventured and fewer still come back alive, it smashed silently and invisibly against the seas of molten metal, the hills of slowly moving lava. The mere impact could have meant nothing to such an entity; what it could not endure was its first contact with the inconceivable cold of solid matter.

  Yes, cold. It had descended upon the hottest spot in the Solar System, where the temperature never falls below seven hundred degrees Fahrenheit and sometimes approaches a thousand. And that was far, far colder to it than the antarctic winter would be to a naked man.

  We did not see it die, out there in the freezing fire; it was beyond the reach of our instruments now, and none of them recorded its end. Yet every one of us knew when that moment came, and that is why we are not interested when those who have seen only the films and tapes tell us that we were watching some purely natural phenomenon.

  How can one explain what we felt, in that last moment when half our little world was enmeshed in the dissolving tendrils of that huge but immaterial brain? I can only say that it was a soundless cry of anguish, a death pang that seeped into our minds without passing through the gateways of the senses. Not one of us doubted then, or has ever doubted since, that he had witnessed the passing of a giant.

  We may have been both the first and the last of all men to see so mighty a fall. Whatever they may be, in their unimaginable world within the sun, our paths and theirs may never cross again. It is hard to see how we can ever make contact with them, even if their intelligence matches ours.

  And does it? It may be well for us if we never know the answer. Perhaps they have been living there inside the sun since the Universe was born, and have climbed to peaks of wisdom that we shall never scale. The future may be theirs, not ours; already they may be talking across the light-years to their cousins in other stars.

  One day they may discover us, by whatever strange senses they possess, as we circle around their might
y, ancient home, proud of our knowledge and thinking ourselves lords of creation. They may not like what they find, for to them we should be no more than maggots, crawling upon the skins of worlds too cold to cleanse themselves from the corruption of organic life.

  And then, if they have the power, they will do what they

  consider necessary. The sun will put forth its strength and lick the faces of its children; and thereafter the planets will go their way once more as they were in the beginning—clean and bright . . . and sterile.

  Colombo April 1957

  The Wall of Darkness

  Many and strange are the universes that drift like bubbles in the foam upon the River of Time. Some—a very few—move against or athwart its current; and fewer still are those that lie forever beyond its reach, knowing nothing of the future or the past. Shervane's tiny cosmos was not one of these: its strangeness was of a different order. It held one world only— the planet of Shervane's race—and a single star, the great sun Trilome that brought it life and light.

  Shervane knew nothing of night, for Trilorne was always high above the horizon, dipping near it only in the long months of winter. Beyond the borders of the Shadow Land, it was true, there came a season when Trilorne disappeared below the edge of the world, and a darkness fell in which nothing could live. But even then the darkness was not absolute, though there were no stars to relieve it.

  Alone in its little cosmos, turning the same face always toward its solitary sun, Shervane's world was the last and the strangest jest of the Maker of the Stars.

  Yet as he looked across his father's lands, the thoughts that filled Shervane's mind were those that any human child might have known. He felt awe, and curiosity, and a little fear, and above all a longing to go out into the great world before him. These things he was still too young to do, but the ancient

  house was on the highest ground for many miles and he could look far out over the land that would one day be his. When he turned to the north, with Trilorne shining full upon his face, he could see many miles away the long line of mountains that curved around to the right, rising higher and higher, until they disappeared behind him in the direction of the Shadow Land. One day, when he was older, he would go through those mountains along the pass that led to the great lands of the east.

  On his left was the ocean, only a few miles away, and sometimes Shervane could hear the thunder of the waves as they fought and tumbled on the gently sloping sands. No one knew how far the ocean reached. Ships had set out across it, sailing northward while Trilorne rose higher and higher in the sky and the heat of its rays grew ever more intense. Long before the great sun had reached the zenith, they had been forced to return. If the mythical Fire Lands did indeed exist, no man could ever hope to reach their burning shores—unless the legends were really true. Once, it was said, there had been swift metal ships that could cross the ocean despite the heat of Trilorne, and so come to the lands on the other side of the world. Now these countries could be reached only by a tedious journey over land and sea, which could be shortened no more than a little by traveling as far north as one dared.

  All the inhabited countries of Shervane's world lay in the narrow belt between burning heat and insufferable cold. In every land, the far north was an unapproachable region smitten by the fury of Trilorne. And to the south of all countries lay the vast and gloomy Shadow Land, where Trilorne was never more than a pale disk on the horizon, and often was not visible at all.

  These things Shervane learned in the years of his childhood, and in those years he had no wish to leave the wide lands between the mountains and the sea. Since the dawn of time his ancestors and the races before them had toiled to make these lands the fairest in the world; if they had failed, it was by a narrow margin. There were gardens bright with

  strange flowers, there were streams that trickled gently between moss-grown rocks to be lost in the pure waters of the tideless sea. There were fields of grain that rustled continually in the wind, as if the generations of seeds yet unborn were talking one to the other. In the wide meadows and beneath the trees the friendly cattle wandered aimlessly with foolish cries. And there was the great house, with its enormous rooms and its endless corridors, vast enough in reality but huger still to the mind of a child. This was the world in which Shervane had passed his years, the world he knew and loved. As yet, what lay beyond its borders had not concerned his mind.

  But Shervane's universe was not one of those free from the domination of time. The harvest ripened and was gathered into the granaries; Trilorne rocked slowly through its little arc of sky, and with the passing seasons Shervane's mind and body grew. His land seemed smaller now: the mountains were nearer and the sea was only a brief walk from the great house. He began to learn of the world in which he lived, and to be made ready for the part he must play in its shaping.

  Some of these things he learned from his father, Sherval, but most he was taught by Grayle, who had come across the mountains in the days of his father's father, and had now been tutor to three generations of Shervane's family. He was fond of Grayle, though the old man taught him many things he had no wish to learn, and the years of his boyhood passed pleasantly enough until the time came for him to go through the mountains into the lands beyond. Ages ago his family had come from the great countries of the east, and in every generation since, the eldest son had made that pilgrimage again to spend a year of his youth among his cousins. It was a wise custom, for beyond the mountains much of the knowledge of the past still lingered, and there one could meet men from other lands and study their ways.

  In the last spring before his son's departure, Sherval collected three of his servants and certain animals it is convenient to call horses, and took Shervane to see those parts of

  the land he had never visited before. They rode west to the sea, and followed it for many days, until Trilorne was noticeably nearer the horizon. Still they went south, their shadows lengthening before them, turning again to the east only when the rays of the sun seemed to have lost all their power. They were now well within the limits of the Shadow Land, and it would not be wise to go farther south until the summer was at its height.

  Shervane was riding beside his father, watching the changing landscape with all the eager curiosity of a boy seeing a new country for the first time. His father was talking about the soil, describing the crops that could be grown here and those that would fail if the attempt were made. But Shervane's attention was elsewhere: he was staring out across the desolate Shadow Land, wondering how far it stretched and what mysteries it held.

  "Father," he said presently, "if you went south in a straight line, right across the Shadow Land, would you reach the other side of the world?"

  His father smiled.

  "Men have asked that question for centuries," he said, "but there are two reasons why they will never know the answer."

  "What are they?"

  "The first, of course, is the darkness and the cold. Even here, nothing can live during the winter months. But there is a better reason, though I see that Grayle has not spoken of it."

  "I don't think he has: at least, I do not remember."

  For a moment Sherval did not reply. He stood up in his stirrups and surveyed the land to the south.

  "Once I knew this place well," he said to Shervane. "Come —I have something to show you."

  They turned away from the path they had been following, and for several hours rode once more with their backs to the sun. The land was rising slowly now, and Shervane saw that they were climbing a great ridge of rock that pointed like a dagger into the heart of the Shadow Land. They came pres-

  ently to a hill too steep for the horses to ascend, and here they dismounted and left the animals in the servants' charge.

  "There is a way around," said Sherval, "but it is quicker for us to climb than to take the horses to the other side."

  The hill, though steep, was only a small one, and they reached its summit in a few minutes. At first Shervane could see n
othing he had not met before; there was only the same undulating wilderness, which seemed to become darker and more forbidding with every yard that its distance from Trilorne increased.

  He turned to his father with some bewilderment, but Sherval pointed to the far south and drew a careful line along the horizon.

  "It is not easy to see," he said quietly. "My father showed it to me from this same spot, many years before you were born."

  Shervane stared into the dusk. The southern sky was so dark as to be almost black, and it came down to meet the edge of the world. But not quite, for along the horizon, in a great curve dividing land from sky yet seeming to belong to neither, was a band of deeper darkness, black as the night which Shervane had never known.

  He looked at it steadfastly for a long time, and perhaps some hint of the future may have crept into his soul, for the darkling land seemed suddenly alive and waiting. When at last he tore his eyes away, he knew that nothing would ever be the same again, though he was still too young to recognize the challenge for what it was.

  And so, for the first time in his life, Shervane saw the Wall.

  In the early spring he said farewell to his people, and went with one servant over the mountains into the great lands of the eastern world. Here he met the men who shared his ancestry, and here he studied the history of his race, the arts that had grown from ancient times, and the sciences that ruled the lives of men. In the places of learning he made friends with boys who had come from lands even farther to

  the east: few of these was he likely to see again, but one was to play a greater part in his life than either could have imagined. Brayldon's father was a famous architect, but his son intended to eclipse him. He was traveling from land to land, always learning, watching, asking questions. Though he was only a few years older than Shervane, his knowledge of the world was infinitely greater—or so it seemed to the younger boy.