Later, there would be time enough to see that Diaspar realized the truth: for the moment Alvin was too interested in the robot to worry about much else. He felt, and his belief was now shared by Rorden, that the tale he had heard in Shalmirane was only a fragment of some far greater story. At first Rorden had been skeptical, and he still believed the "Great Ones" to be no more than another of the world's countless religious myths. Only the robot knew the truth, and it had defied a million centuries of questioning as it was defying them now.

             "The trouble is," said Rorden, "that there are no longer any engineers left in the world."

             Alvin looked puzzled: although contact with the Keeper of the Records had greatly enlarged his vocabulary, there were thousands of archaic words he did not understand.

             "An engineer," explained Rorden, "was a man who designed and built machines. It's impossible for us to imagine an age without robots—but every machine in the world had to be invented at one time or other, and until the Master Robots were built they needed men to look after them. Once the machines could care for themselves, human engineers were no longer required. I think that's a fairly accurate account, though of course it's mostly guesswork. Every machine we possess existed at the beginning of our history, and many had disappeared long before it started."

             "Such as flyers and spaceships," interjected Alvin.

             "Yes," agreed Rorden, "as well as the great communicators that could reach the stars. All these things vanished when they were no longer needed."

             Alvin shook his head.

             "I still believe," he said, "that the disappearance of the spaceships can't be explained as easily as that. But to get back to the machine— do you think that the Master Robots could help us? I've never seen one, of course, and don't know much about them."

             "Help us? In what way?"

             "I'm not quite sure," said Alvin vaguely. "Perhaps they could force it to obey all my orders. They repair robots, don't they? I suppose that would be a kind of repair. . . ."

             His voice faded away as if he had failed even to convince himself.

             Rorden smiled: the idea was too ingenuous for him to put much faith in it. However, this piece of historical research was the first of all Alvin's schemes for which he himself could share much enthusiasm, and he could think of no better plan at the moment.

             He walked toward the Associator, above which the robot was still floating as if in studied indifference. As he began, almost automatically, to set up his questions on the great keyboard, he was suddenly struck by a thought so incongruous that he burst out laughing.

             Alvin looked at his friend in surprise as Rorden turned toward him.

             "Alvin," he said between chuckles, "I'm afraid we still have a lot to learn about machines." He laid his hand on the robot's smooth metal body. "They don't share many human feelings, you know. It wasn't really necessary for us to do all our plotting in whispers."

11

             This world, Alvin knew, had not been made for Man. Under the glare of the trichromatic lights—so dazzling that they pained the eyes—the long, broad corridors seemed to stretch to infinity. Down these great passageways all the robots of Diaspar must come at the end of their patient lives, yet not once in a million years had they echoed to the sound of human feet.

             It had not been difficult to locate the maps of the underground city, the city of machines without which Diaspar could not exist. A few hundred yards ahead the corridor would open into a circular chamber more than a mile across, its roof supported by great columns that must also bear the unimaginable weight of Power Center. Here, if the maps spoke the truth, the Master Robots, greatest of all machines, kept watch over Diaspar.

             The chamber was there, and it was even vaster than Alvin had imagined—but where were the machines? He paused in wonder at the tremendous but meaningless panorama beneath him. The corridor ended high in the wall of the chamber—surely the largest cavity ever built by man—and on either side long ramps swept down to the distant floor. Covering the whole of that brilliantly lit expanse were hundreds of great white structures, so unexpected that for a moment Alvin thought he must be looking down upon a subterranean city. The impression was startlingly vivid and it was one he never wholly lost. Nowhere at all was the sight he had expected— the familiar gleam of metal which since the beginning of time Man had learned to associate with his servants.

             Here was the end of an evolution almost as long as Man's. Its beginning was lost in the mists of the Dawn Ages, when humanity had first learned the use of power and sent its noisy engines clanking about the world. Steam, water, wind—all had been harnessed for a little while and then abandoned. For centuries the energy of matter had run the world until it too had been superseded, and with each change the old machines were forgotten and the new ones took their place. Very slowly, over millions of years, the ideal of the perfect machine was approached—that ideal which had once been a dream, then a distant prospect, and at last reality:

             No machine may contain any moving parts.

             Here was the ultimate expression of that ideal. Its achievement had taken Man perhaps a thousand million years, and in the hour of his triumph he had turned his back upon the machine forever.

             The robot they were seeking was not as large as many of its companions, but Alvin and Rorden felt dwarfed when they stood beneath it. The five tiers with their sweeping horizontal lines gave the impression of some crouching beast, and looking from it to his own robot Alvin thought it strange that the same word should be used for both.

             Almost three feet from the ground a wide transparent panel ran the whole length of the structure. Alvin pressed his forehead against the smooth, curiously warm material and peered into the machine. At first he saw nothing: then, by shielding his eyes, he could distinguish thousands of faint points of light hanging in nothingness. They were ranged one beyond the other in a three-dimensional lattice, as strange and as meaningless to him as the stars must have been to ancient Man.

             Rorden had joined him and together they stared into the brooding monster. Though they watched for many minutes, the colored lights never moved from their places and their brilliance never changed. Presently Alvin broke away from the machine and turned to his friend.

             "What are they?" he asked in perplexity.

             "If we could look into our own minds," said Rorden, "they would mean as little to us. The robots seem motionless because we cannot see their thoughts."

             For the first time Alvin looked at the long avenue of titans with some trace of understanding. All his life he had accepted without question the miracle of the synthesizers, the machines which age after age produced in an unending stream all that the city needed. Thousands of times he had watched that act of creation, never thinking that somewhere must exist the prototype of that which he had seen come into the world.

             As a human mind may dwell for a little while upon a single thought, so these greater brains could grasp and hold forever the most intricate ideas. The patterns of all created things were frozen in these eternal minds, needing only the touch of a human will to make them reality.