Arthur Clarke - Against the Fall of Night

“What are you doing?” asked Alvin.

“Employing a little logic and a great deal of intuition,” replied Rorden. He refused to say any more, and Alvin resumed his examination of the statue. He was still doing this when a faint sound behind him attracted his attention. Rorden, his face wreathed in smiles, was slowly sinking into the floor. He began to laugh at the boy’s expression.

“I think I know how to reverse this,” he said as he disappeared. “If I don’t come up immediately, you’ll have to pull me out with a gravity polarizer. But I don’t think it will be necessary.”

The last words were muffled, and, rushing to the edge of the rectangular pit, Alvin saw that his friend was already many feet below the surface. Even as he watched, the shaft deepened swiftly until Rorden had dwindled to a speck no longer recognizable as a human being. Then, to Alvin’s relief, the far-off rectangle of light began to expand and the pit shortened until Rorden was standing beside him once more.

For a moment there was a profound silence. Then Rorden smiled and began to speak.

“Logic,” he said, “can do wonders if it has something to work upon. This building is so simple that it couldn’t conceal anything, and the only possible secret exit must be through the floor. I argued that it would be marked in some way, so I searched until I found a slab that differed from all the rest.”

Alvin bent down and examined the floor.

“But it’s just the same as all the others!” he protested.

Rorden put his hands on the boy’s shoulders and turned him round until he was looking towards the statue. For a moment Alvin stared at it intently. Then he slowly nodded his head.

“I see,” he whispered. “So that is the secret of Yarlan Zey!”

The eyes of the statue were fixed upon the floor at his feet. There was no mistake. Alvin moved to the next slab, and found that Yarlan Zey was no longer looking towards him.

“Not one person in a thousand would ever notice that unless they were looking for it,” said Rorden, “and even then, it would mean nothing to them. At first I felt rather foolish myself, standing on that slab and going through different combinations of control thoughts. Luckily the circuits must be fairly tolerant, and the code thought turned out to be ‘Alaine of Lyndar.’ I tried TTarlan Zey’ at first, but it wouldn’t work, as I might have guessed. Too many people would have operated the machine by accident if that trigger thought had been used.”

“It sounds very simple,” admitted Alvin, “but I don’t think I would have found it in a thousand years. Is that how the Associators work?”

Rorden laughed. “Perhaps,” he said. “I sometimes reach the answer before they do, but they always reach it.” He paused for a moment. “We’ll have to leave the shaft open: no one is likely to fall down it.”

As they sank smoothly into the earth, the rectangle of sky dwindled until it seemed very small and far away. The shaft was lit by a phosphorescence that was part of the walls, and seemed to be at least a thousand feet deep. The walls were perfectly smooth and gave no indication of the machinery that had lowered them.

The doorway at the bottom of the shaft opened automatically as they stepped towards it. A few paces took them through the short corridor-and then they were standing, overawed by its immensity, in a great circular cavern whose walls came together in a graceful, sweeping curve three hundred feet above their heads. The column against which they were standing seemed too slender to support the hundreds of feet of rock above it. Then Alvin noticed that it did not seem an integral part of the chamber at all, but was clearly of much later construction. Rorden had come to the same conclusion.

“This column,” he said, “was built simply to house the shaft down which we came. We were right about the moving ways-they all lead into this place.”

Alvin had noticed, without realizing what they were, the great tunnels that pierced the circumference of the chamber. He could see that they sloped gently upwards, and now he recognized the familiar grey surface of the moving ways. Here, far beneath the heart of the city, converged the wonderful transport system that carried all the traffic of Diaspar. But these were only the severed stumps of the great roadways: the strange material that gave them life was now frozen into immobility.

Alvin began to walk towards the nearest of the tunnels. He had gone only a few paces when he realized that something was happening to the ground beneath his feet. It was becoming transparent. A few more yards, and he seemed to be standing in mid-air without any visible support. He stopped and stared down into the void beneath.

“Rorden!” he called. “Come and look at this!”

The other joined him, and together they gazed at the marvel beneath their feet. Faintly visible, at an indefinite depth, lay an enormous map-a great network of lines converging towards a spot beneath the central shaft. At first it seemed a confused maze, but after a while Alvin was able to grasp its main outlines. As usual, he had scarcely begun his own analysis before Rorden had finished his.

“The whole of this floor must have been transparent once,” said the Keeper of the Records. “When this chamber was sealed and the shaft built, the engineers must have done something to make the center opaque. Do you understand what it is, Alvin?”

“I think so,” replied the boy. “It’s a map of the transport system, and those little circles must be the other cities of Earth. I can just see names beside them, but they’re too faint to read.”

“There must have been some form of internal illumination once,” said Rorden absently. He was looking towards the walls of the chamber.

“I thought so!” he exclaimed. “Do you see how all these radiating lines lead towards the small tunnels?”

Alvin had noticed that besides the great arches of the moving ways there were innumerable smaller tunnels leading out of the chamber-tunnels that sloped downwards instead of up.

Rorden continued without waiting for a reply.

“It was a magnificent system. People would come down the moving ways, select the place they wished to visit, and then follow the appropriate Hue on the map.”

“And what happens then?” said Alvin.

As usual, Rorden refused to speculate.

“I haven’t enough information,” he answered. “I wish we could read the names of those cities!” he complained, changing the subject abruptly.

Alvin had wandered away and was circumnavigating the central pillar. Presently his voice came to Rorden, slightly muffled and overlaid with echoes from the walls of the chamber.

“What is it?” called Rorden, not wishing to move, because he had nearly deciphered one of the dimly visible groups of characters. But Alvin’s voice was insistent, so he went to join him.

Far beneath was the other half of the great map, its faint webwork radiating towards the points of the compass. But this time not all of it was too dim to be clearly seen, for one of the lines, and one only, was brilliantly illuminated. It seemed to have no connection with the rest of the system, and pointed like a gleaming arrow to one of the downward-sloping tunnels. Near its end the line transfixed a circle of golden light, and against that circle was the single word “LYS.” That was all.

For a long time Alvin and Rorden stood gazing down at that silent symbol. To Rorden it was no more than another question for his machines, but to Alvin its promise was boundless. He tried to imagine this great chamber as it had been in the ancient days, when air transport had come to an end but the cities of Earth still had commerce one with the other. He thought of the countless millions of years that had passed with the traffic steadily dwindling and the lights on the great map dying one by one, until at last only this single line remained. He wondered how long it had gleamed there among its darkened companions, waiting to guide the steps that never came, until at last Yarlan Zey had sealed the moving ways and closed Diaspar against the world.