to the Tomb. Once the secret was realized, there could be no doubt about it. Alvin moved to -the next slab, and found that Yarlan Zey was no longer looking toward him.
He rejoined Khedron, and mentally echoed the words that the Jester spoke aloud: "Diaspar was not always thus." Instantly, as if the millions of years that had lapsed since their last operation had never existed, the waiting machines responded. The great slab of stone on which they were standing began to carry them smoothly into the depths.
Overhead, the patch of blue suddenly flickered out of existence. The shaft was no longer open; there was no danger that anyone should accidentally stumble into it. Alvin wondered fleetingly if another slab of stone had somehow been materialized to replace the one now supporting him and Khedron, then decided against it. The original slab probably still paved the Tomb; the one upon which they were standing might only exist for infinitesimal fractions of a second, being continuously re-created at greater and greater depths in the earth to give the illusion of steady downward movement.
Neither Alvin nor Khedron spoke as the walls flowed silently past them. Khedron was once again wrestling with his conscience, wondering if this time he had gone too far. He could not imagine where this route might lead, if indeed it led anywhere. For the first time in his life, he began to understand the real meaning of fear.
Alvin was not afraid; he was too excited. This was the sensation he had known in the Tower of Loranne, when he had looked out across the untrodden desert and seen the stars conquering the night sky. He had merely gazed at the iuknown then; he was being carried toward it now.
The walls ceased to flow past them. A patch of light appeared at one side of their mysteriously moving room, grew brighter and brighter, and was suddenly a door. They stepped through it, took a few paces along the short corridor beyond -and then were standing in a great, circular cavern whose walls came together in a sweeping curve three hundred feet above their heads.
The column down whose interior they had descended seemed far too slim to support the millions of tons of rock above it; indeed, it did not seem to be an integral part of the chamber at all, but gave the impression of being an afterthought. Khedron, following Alvin's gaze, arrived at the same conclusion.
"This column," he said, speaking rather jerkily, as if anxious to find something to say, "was built simply to house the shaft down which we came. It could never have carried the traffic that must have passed through here when Diaspar was still open to the world. That came through those tunnels over there; I suppose you recognize what they are?"
Alvin looked toward the walls of the chamber, more than a hundred yards away. Piercing them at regular intervals were large tunnels, twelve of them, radiating in all directions exactly as the moving ways still did today. He could see that they sloped gently upward, and now he recognized the familiar gray surface of the moving ways. These were only the severed stumps of the great roads; the strange material that gave them life was now frozen into immobility. When the park had been built, the hub of the moving way system had been buried. But it had never been destroyed.
Alvin began to walk toward 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 midair without visible support. He stopped and stared down into the void beneath him.
"Khedron!" 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 toward a spot beneath the central shaft. They stared at it in silence for a moment; then Khedron said quietly: You realize what this is?"
"I think so," replied Alvin. "It's a map of the entire 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 Khedron absently. He was tracing the lines beneath his feet, following them with his eyes out