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 nothing 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.

Between them they took the world to pieces and rebuilt it according to their desires. Brayldon dreamed of cities whose great avenues and stately towers would shame even the wonders of the past, but Shervane's interests lay more with the people who would dwell in those cities, and the way they ordered their lives.

They often spoke of the Wall, which Brayldon knew from the stories of his own people, though he himself had never seen it. Far to the south of every country, as Shervane had learned, it lay like a great barrier athwart the Shadow Land. In high summer it could be reached, though only with difficulty, but nowhere was there any way of passing it, and none knew what lay beyond. An entire world, never pausing even when it reached a hundred times the height of a man, it encircled the wintry sea that washed the shores of the Shadow Land. Travelers had stood upon those lonely beaches, scarcely warmed by the last thin rays of Trilorne, and had seen how the dark shadow of the Wall marched out to sea contemptuous of the waves beneath its feet. And on the far shores, other travelers had watched it come striding in across the ocean, to sweep past them on its journey round the world.

"One of my uncles," said Brayldon, "once reached the Wall when he was a young man. He did it for a wager, and he rode for ten days before he came beneath it. I think it frightened him—it was so huge and cold. He could not tell whether it was made of metal or of stone, and when he shouted, there was no echo at all, but his voice died away quickly as if the Wall were swallowing the sound. My people believe it is the end of the world, and there is nothing beyond."

"If that were true," Shervane replied, with irrefutable logic, "the ocean would have poured over the edge before the Wall was built."

"Not if Kyrone built it when He made the world."

Shervane did not agree.

"My people believe it is the work of man—perhaps the engineers of the First Dynasty, who made so many wonderful things. If they really had ships that could reach the Fire Lands—and even ships that could fly—they might have possessed enough wisdom to build the Wall."

Brayldon shrugged.

"They must have had a very good reason," he said. "We can never know the answer, so why worry about it?"

This eminently practical advice, as Shervane had discovered, was all that the ordinary man ever gave him. Only philosophers were interested in unanswerable questions: to most people, the enigma of the Wall, like the problem of existence itself, was something that scarcely concerned their minds. And all the philosophers he had met had given him different answers.

First there had been Grayle, whom he had questioned on his return from the Shadow Land. The old man had looked at him quietly and said:

"There is only one thing behind the Wall, so I have heard. And that is madness."

Then there had been Artex, who was so old that he could scarcely hear Shervane's nervous questioning. He gazed at the boy through eyelids that seemed too tired to open fully, and had replied after a long time:

"Kyrone built the Wall in the third day of the making of the world. What is beyond, we shall discover when we die— for there go the souls of all the dead."

Yet Irgan, who lived in the same city, had flatly contradicted this.

"Only memory can answer your question, my son. For behind the Wall is the land in which we lived before our births."

Whom could he believe? The truth was that no one knew:

if the knowledge had ever been possessed, it had been lost ages since.

Though this quest was unsuccessful, Shervane had learned many things in his year of study. With the returning spring he said farewell to Brayldon and the other friends he had known for such a little while, and set out along the ancient road that led him back to his own country. Once again he made the perilous journey through the great pass between the mountains, where walls of ice hung threatening against the sky. He came to the place where the road curved down once more toward the world of men, where there was warmth and running water and the breath no longer labored in the freezing air. Here, on the last rise of the road before it descended into the valley, one could see far out across the land to the distant gleam of the ocean. And there, almost lost in the mists at the edge of the world, Shervane could see the line of shadow that was his own country.

He went on down the great ribbon of stone until he came to the bridge that men had built across the cataract in the ancient days when the only other way had been destroyed by earthquake. But the bridge was gone: the storms and avalanches of early spring had swept away one of the mighty piers, and the beautiful metal rainbow lay a twisted ruin in the spray and foam a thousand feet below. The summer would have come and gone before the road could be opened once more: as Shervane sadly returned he knew that another year must pass ere he would see his home again.

He paused for many minutes on the last curve of the road, looking back toward the unattainable land that held all the things he loved. But the mists had closed over it, and he saw it no more. Resolutely he turned back along the road until the open lands had vanished and the mountains enfolded him again.

Brayldon was still in the city when Shervane returned. He was surprised and pleased to see his friend, and together they discussed what should be done in the year ahead. Shervane's cousins, who had grown fond of their guest, were not sorry to

see him again, but their kindly suggestion that he should devote another year to study was not well received.

Shervane's plan matured slowly, in the face of considerable opposition. Even Brayldon was not enthusiastic at first, and much argument was needed before he would co-operate. Thereafter, the agreement of everyone else who mattered was only a question of time.

Summer was approaching when the two boys set out toward Brayldon's country. They rode swiftly, for the journey was a long one and must be completed before Trilorne began its winter fall. When they reached the lands that Brayldon knew, they made certain inquiries which caused much shaking of heads. But the answers they obtained were accurate, and soon the Shadow Land was all around them, and presently for the second time in his life Shervane saw the Wall.

It seemed not far away when they first came upon it, rising from a bleak and lonely plain. Yet they rode endlessly across that plain before the Wall grew any nearer—and then they had almost reached its base before they realized how close they were, for there was no way of judging its distance until one could reach out and touch it.

When Shervane gazed up at the monstrous ebony sheet that had so troubled his mind, it seemed to be overhanging and about to crush him beneath its falling weight. With difficulty, he tore his eyes away from the hypnotic sight, and went nearer to examine the material of which the Wall was built.

It was true, as Brayldon had told him, that it felt cold to the touch—colder than it had any right to be even in this sun-starved land. It felt neither hard nor soft, for its texture eluded the hand in a way that was difficult to analyze. Shervane had the impression that something was preventing him from actual contact with the surface, yet he could see no space between the Wall and his fingers when he forced them against it. Strangest of all was the uncanny silence of which Brayldon's uncle had spoken: every word was deadened and all sounds died away with unnatural swiftness.

Brayldon had unloaded some tools and instruments from

the pack horses, and had begun to examine the Wall's surface. He found very quickly that no drills or cutters would mark it in any way, and presently he came to the conclusion Shervane had already reached. The Wall was not merely adamant: it was unapproachable.

At last, in disgust, he took a perfectly straight metal rule and pressed its edge against the wall. While Shervane held a mirror to reflect the feeble light of Trilorne along the line of contact, Brayldon peered at the rule from the other side. It was as he had thought: an infinitely narrow streak of light showed unbroken between the two surfaces.

Brayldon looked thoughtfully at his friend.

"Shervane," he said, "I don't believe the Wall is made of matter, as we know it."

"Then perhaps the legends were right that said it was never built at all, but created as we see it now."

"I think so too," said Brayldon. "The engineers of the First Dynasty had such powers. There are some very ancient buildings in my land that seem to have been made in a single operation from a substance that shows absolutely no sign of weathering. If it were black instead of colored, it would be very much like the material of the Wall."

He put away his useless tools and began to set up a simple portable theodolite.

"If I can do nothing else," he said with a wry smile, "at least I can find exactly how high it is!"

When they looked back for their last view of the Wall, Shervane wondered if he would ever see it again. There was nothing more he could learn: for the future, he must forget this foolish dream that he might one day master its secret. Perhaps there was no secret at all—perhaps beyond the Wall the Shadow Land stretched round the curve of the world until it met that same barrier again. That, surely, seemed the likeliest thing. But if it were so, then why had the Wall been built, and by what race?

With an almost angry effort of will, he put these thoughts aside and rode forward into the light of Trilorne, thinking of a

future in which the Wall would play no more part than it did in the lives of other men.

So two years had passed before Shervane could return to his home. In two years, especially when one is young, much can be forgotten and even the things nearest to the heart lose their distinctness, so that they can no longer be clearly recalled. When Shervane came through the last foothills of the mountains and was again in the country of his childhood, the joy of his home-coming was mingled with a strange sadness. So many things were forgotten that he had once thought his mind would hold forever.

The news of his return had gone before him, and soon he saw far ahead a line of horses galloping along the road. He pressed forward eagerly, wondering if Sherval would be there to greet him, and was a little disappointed when he saw that Grayle was leading the procession.

Shervane halted as the old man rode up to his horse. Then Grayle put his hand upon his shoulder, but for a while he turned away his head and could not speak.

And presently Shervane learned that the storms of the year before had destroyed more than the ancient bridge, for the lightning had brought his own home in ruins to the ground. Years before the appointed time, all the lands that Sherval had owned had passed into the possession of his son. Far more, indeed, than these, for the whole family had been assembled, according to its yearly custom, in the great house when the fire had come down upon it. In a single moment of time, everything between the mountains and the sea had passed into his keeping. He was the richest man his land had known for generations; and all these things he would have given to look again into the calm gray eyes of the father he would see no more.

Trilorne had risen and fallen in the sky many times since Shervane took leave of his childhood on the road before the mountains. The land had flourished in the passing years, and

the possessions that had so suddenly become his had steadily increased their value. He had husbanded them well, and now he had time once more in which to dream. More than that—he had the wealth to make his dreams come true.

Often stories had come across the mountains of the work Brayldon was doing in the east, and although the two friends had never met since their youth they had exchanged messages regularly. Brayldon had achieved his ambitions: not only had he designed the two largest buildings erected since the ancient days, but a whole new city had been planned by him, though it would not be completed in his lifetime. Hearing of these things, Shervane remembered the aspirations of his own youth, and his mind went back across the years to the day when they had stood together beneath the majesty of the Wall. For a long time he wrestled with his thoughts, fearing to revive old longings that might not be assuaged. But at last he made his decision and wrote to Brayldon—for what was the use of wealth and power unless they could be used to shape one's dreams?

Then Shervane waited, wondering if Brayldon had forgotten the past in the years that had brought him fame. He had not long to wait: Brayldon could not come at once, for he had great works to carry to their completion, but when they were finished he would join his old friend. Shervane had thrown him a challenge that was worthy of his skill—one which if he could meet would bring him more satisfaction than anything he had yet done.

Early the next summer he came, and Shervane met him on the road below the bridge. They had been boys when they last parted, and now they were nearing middle age, yet as they greeted one another the years seemed to fall away and each was secretly glad to see how lightly Time had touched the friend he remembered.

They spent many days in conference together, considering the plans that Brayldon had drawn up. The work was an immense one, and would take many years to complete, but it

was possible to a man of Shervane's wealth. Before he gave his final assent, he took his friend to see Grayle.

The old man had been living for some years in the little house that Shervane had built him. For a long time he had played no active part in the life of the great estates, but his advice was always ready when it was needed, and it was invariably wise.

Grayle knew why Brayldon had come to this land, and he expressed no surprise when the architect unrolled his sketches. The largest drawing showed the elevation of the Wall, with a great stairway rising along its side from the plain beneath. At six equally spaced intervals the slowly ascending ramp leveled out into wide platforms, the last of which was only a short distance below the summit of the Wall. Springing from the stairway at a score of places along its length were flying buttresses which to Grayle's eye seemed very frail and slender for the work they had to do. Then he realized that the great ramp would be largely self-supporting, and on one side all the lateral thrust would be taken by the Wall itself.

He looked at the drawing in silence for a while, and then remarked quietly:

"You always managed to have your way, Shervane. I might have guessed that this would happen in the end."

"Then you think it a good idea?" Shervane asked. He had never gone against the old man's advice, and was anxious to have it now. As usual Grayle came straight to the point.

"How much will it cost?" he said.

Brayldon told him, and for a moment there was a shocked silence.

"That includes," the architect said hastily, "the building of a good road across the Shadow Land, and the construction of a small town for the workmen. The stairway itself is made from about a million identical blocks which can be dovetailed together to form a rigid structure. We shall make these, I hope, from the minerals we find in the Shadow Land."

He sighed a little.

"I should have liked to have built it from metal rods, jointed together, but that would have cost even more, for all the material would have to be brought over the mountains."

Grayle examined the drawing more closely.

"Why have you stopped short of the top?" he asked.

Brayldon looked at Shervane, who answered the question with a trace of embarrassment.

"I want to be the only one to make the final ascent," he replied. "The last stage will be by a lifting machine on the highest platform. There may be danger: that is why I am going alone."

That was not the only reason, but it was a good one. Behind the Wall, so Grayle had once said, lay madness. If that were true, no one else need face it.

Grayle was speaking once more in his quiet, dreamy voice.

"In that case," he said, "what you do is neither good nor bad, for it concerns you alone. If the Wall was built to keep something from our world, it will still be impassable from the other side."

Brayldon nodded.

"We had thought of that," he said with a touch of pride. "If the need should come, the ramp can be destroyed in a moment by explosives at selected spots."

"That is good," the old man replied. "Though I do not believe those stories, it is well to be prepared. When the work is finished, I hope I shall still be here. And now I shall try to remember what I heard of the Wall when I was as young as you were, Shervane, when you first questioned me about it."

Before the winter came, the road to the Wall had been marked out and the foundations of the temporary town had been laid. Most of the materials Brayldon needed were not hard to find, for the Shadow Land was rich in minerals. He had also surveyed the Wall itself and chosen the spot for the stairway. When Trilorne began to dip below the horizon, Brayldon was well content with the work that had been done.

By the next summer the first of the myriad concrete blocks

had been made and tested to Brayldon's satisfaction, and before winter came again some thousands had been produced and part of the foundations laid. Leaving a trusted assistant in charge of the production, Brayldon could now return to his interrupted work. When enough of the blocks had been made, he would be back to supervise the building, but until then his guidance would not be needed.

Two or three times in the course of every year, Shervane rode out to the Wall to watch the stockpiles growing into great pyramids, and four years later Brayldon returned with him. Layer by layer the lines of stone started to creep up the flanks of the Wall, and the slim buttresses began to arch out into space. At first the stairway rose slowly, but as its summit narrowed the increase became more and more rapid. For a third of every year the work had to be abandoned, and there were anxious months in the long winter when Shervane stood on the borders of the Shadow Land, listening to the storms that thundered past him into the reverberating darkness. But Brayldon had built well, and every spring the work was standing unharmed as though it would outlive the Wall itself.

The last stones were laid seven years after the beginning of the work. Standing a mile away, so that he could see the structure in its entirety, Shervane remembered with wonder how all this had sprung from the few sketches Brayldon had shown him years ago, and he knew something of the emotion the artist must feel when his dreams become reality. And he remembered, too, the day when, as a boy by his father's side, he had first seen the Wall far off against the dusky sky of the Shadow Land.

There were guardrails around the upper platform, but Shervane did not care to go near its edge. The ground was at a dizzying distance, and he tried to forget his height by helping Brayldon and the workmen erect the simple hoist that would lift him the remaining twenty feet. When it was ready he stepped into the machine and turned to his friend with all the assurance he could muster.

"I shall be gone only a few minutes," he said with elabo-

rate casualness. Whatever I find, I'll return immediately." He could hardly have guessed how small a choice was his.

Grayle was now almost blind and would not know another spring. But he recognized the approaching footsteps and greeted Brayldon by name before his visitor had time to speak.

"I am glad you came," he said. "I've been thinking of everything you told me, and I believe I know the truth at last. Perhaps you have guessed it already."

"No," said Brayldon. "I have been afraid to think of it."

The old man smiled a little.

"Why should one be afraid of something merely because it is strange? The Wall is wonderful, yes—but there's nothing terrible about it, to those who will face its secret without flinching.

"When I was a boy, Brayldon, my old master once said that time could never destroy the truth—it could only hide it among legends. He was right. From all the fables that have gathered around the Wall, I can now select the ones that are part of history.

"Long ago, Brayldon, when the First Dynasty was at its height, Trilorne was hotter than it is now and the Shadow Land was fertile and inhabited—as perhaps one day the Fire Lands may be when Trilorne is old and feeble. Men could go southward as they pleased, for there was no Wall to bar the way. Many must have done so, looking for new lands in which to settle. What happened to Shervane happened to them also, and it must have wrecked many minds—so many that the scientists of the First Dynasty built the Wall to prevent madness from spreading through the land. I cannot believe that this is true, but the legend says that it was made in a single day, with no labor, out of a cloud that encircled the world."

He fell into a reverie, and for a moment Brayldon did not disturb him. His mind was far in the past, picturing his world as a perfect globe floating in space while the Ancient Ones threw that band of darkness around the equator. False

though that picture was in its most important detail, he could never wholly erase it from his mind.

As the last few feet of the Wall moved slowly past his eyes, Shervane needed all his courage lest he cry out to be lowered again. He remembered certain terrible stories he had once dismissed with laughter, for he came of a race that was singularly free from superstition. But what if, after all, those stories had been true, and the Wall had been built to keep some horror from the world?

He tried to forget these thoughts, and found it not hard to do so once he had passed the topmost level of the Wall. At first he could not interpret the picture his eyes brought him: then he saw that he was looking across an unbroken black sheet whose width he could not judge.

The little platform came to a stop, and he noted with half-conscious admiration how accurate Brayldon's calculations had been. Then, with a last word of assurance to the group below, he stepped onto the Wall and began to walk steadily forward.

At first it seemed as if the plain before him was infinite, for he could not even tell where it met the sky. But he walked on unfaltering, keeping his back to Trilorne. He wished he could have used his own shadow as a guide, but it was lost in the deeper darkness beneath his feet.

There was something wrong: it was growing darker with every footstep he took. Startled, he turned around and saw that the disk of Trilorne had now become pale and dusky, as if seen through a darkened glass. With mounting fear, he realized that this was by no means all that had happened— Trilorne was smaller than the sun he had known all his life.

He shook his head in an angry gesture of defiance. These things were fancies; he was imagining them. Indeed, they were so contrary to all experience that somehow he no longer felt frightened but strode resolutely forward with only a glance at the sun behind.

When Trilorne had dwindled to a point, and the darkness

was all around him, it was time to abandon pretense. A wiser man would have turned back there and then, and Shervane had a sudden nightmare vision of himself lost in this eternal twilight between earth and sky, unable to retrace the path that led to safety. Then he remembered that as long as he could see Trilorne at all he could be in no real danger.

A little uncertainly now, he continued his way with many backward glances at the faint guiding light behind him. Trilorne itself had vanished, but there was still a dim glow in the sky to mark its place. And presently he needed its aid no longer, for far ahead a second light was appearing in the heavens.

At first it seemed only the faintest of glimmers, and when he was sure of its existence he noticed that Trilorne had already disappeared. But he felt more confidence now, and as he moved onward, the returning light did something to subdue his fears.

When he saw that he was indeed approaching another sun, when he could tell beyond any doubt that it was expanding as a moment ago he had seen Trilorne contract, he forced all amazement down into the depths of his mind. He would only observe and record: later there would be time to understand these things. That his world might possess two suns, one shining upon it from either side, was not, after all, beyond imagination.

Now at last he could see, faintly through the darkness, the ebon line that marked the Wall's other rim. Soon he would be the first man in thousands of years, perhaps in eternity, to look upon the lands that it had sundered from his world. Would they be as fair as his own, and would there be people there whom he would be glad to greet?

But that they would be waiting, and in such a way, was more than he had dreamed.

Grayle stretched his hand out toward the cabinet beside him and fumbled for a large sheet of paper that was lying

upon it. Brayldon watched him in silence, and the old man continued.

"How often we have all heard arguments about the size of the Universe, and whether it has any boundaries! We can imagine no ending to space, yet our minds rebel at the idea of infinity. Some philosophers have imagined that space is limited by curvature in a higher dimension—I suppose you know the theory. It may be true of other universes, if they exist, but for ours the answer is more subtle.

"Along the line of the Wall, Brayldon, our Universe comes to an end—and yet does not. There was no boundary, nothing to stop one going onward before the Wall was built. The Wall itself is merely a man-made barrier, sharing the properties of the space in which it lies. Those properties were always there, and the Wall added nothing to them,"

He held the sheet of paper toward Brayldon and slowly rotated it,

"Here," he said, "is a plain sheet. It has, of course, two sides. Can you imagine one that has not?"

Brayldon stared at him in amazement. "That's impossible—ridiculous!"

"But is it?" said Grayle softly. He reached toward the cabinet again and his fingers groped in its recesses. Then he drew out a long, flexible strip of paper and turned vacant eyes to the silently waiting Brayldon.

"We cannot match the intellects of the First Dynasty, but what their minds could grasp directly we can approach by analogy. This simple trick, which seems so trivial, may help you to glimpse the truth."

He ran his fingers along the paper strip, then joined the two ends together to make a circular loop.

"Here I have a shape which is perfectly familiar to you— the section of a cylinder. I run my finger around the inside, so —and now along the outside. The two surfaces are quite distinct: you can go from one to the other only by moving through the thickness of the strip. Do you agree?"

"Of course," said Brayldon, still puzzled. "But what does it prove?"

"Nothing," said Grayle. "But now watch—"


This sun, Shervane thought, was Trilorne's identical twin. The darkness had now lifted completely, and there was no longer the sensation, which he would not try to understand, of walking across an infinite plain.

He was moving slowly now, for he had no desire to come too suddenly upon that vertiginous precipice. In a little while he could see a distant horizon of low hills, as bare and lifeless as those he had left behind him. This did not disappoint him unduly, for the first glimpse of his own land would be no more attractive than this.

So he walked on: and when presently an icy hand fastened itself upon his heart, he did not pause as a man of lesser courage would have done. Without flinching, he watched that shockingly familiar landscape rise around him, until he could see the plain from which his journey had started, and the great stairway itself, and at last Brayldon's anxious, waiting face.


Again Grayle brought the two ends of the strip together, but now he had given it a half-twist so that the band was kinked. He held it out to Brayldon.

"Run your finger around it now," he said quietly.

Brayldon did not do so: he could see the old man's meaning.

"I understand," he said. "You no longer have two separate surfaces. It now forms a single continuous sheet—a one-sided surface—something that at first sight seems utterly impossible."

"Yes," replied Grayle very softly. "I thought you would understand. A one-sided surface. Perhaps you realize now why this symbol of the twisted loop is so common in the ancient religions, though its meaning has been completely lost. Of course, it is no more than a crude and simple analogy—an

example in two dimensions of what must really occur in three. But it is as near as our minds can ever get to the truth."

There was a long, brooding silence. Then Grayle sighed deeply and turned to Brayldon as if he could still see his face.

"Why did you come back before Shervane?" he asked, though he knew the answer well enough.

"We had to do it," said Brayldon sadly, "but I did not wish to see my work destroyed."

Grayle nodded in sympathy.

"I understand," he said.


Shervane ran his eye up the long flight of steps on which no feet would ever tread again. He felt few regrets: he had striven, and no one could have done more. Such victory as was possible had been his.

Slowly he raised his hand and gave the signal. The Wall swallowed the explosion as it had absorbed all other sounds, but the unhurried grace with which the long tiers of masonry curtsied and fell was something he would remember all his life. For a moment he had a sudden, inexpressibly poignant vision of another stairway, watched by another Shervane, falling in identical ruins on the far side of the Wall.

But that, he realized, was a foolish thought: for none knew better than he that the Wall possessed no other side.