The City and the Stars Page 0,71

too wise to take it very seriously. Alvin was under a considerable strain, and it would be unsafe to assume that any improvement in his character was permanent.

"That is a very hard question to answer," said Jeserac slowly. "I am tempted to say that all knowledge is valuable, and it cannot be denied that you have added much to our knowledge. But you have also added to our dangers, and in the long run which will be more important? How often have you stopped to consider that?"

For a moment master and pupil regarded each other pensively, each perhaps seeing the other's point of view more clearly than ever before in his life. Then, with one impulse, they turned together down the long passage from the Council Chamber, with their escort still following patiently in the rear.

This world, Alvin knew, had not been made for man. Under the glare of the fierce blue lights-so dazzling that they pained the eyes-the long, broad corridors seemed to stretch to infinity. Down these great passageways, the robots of Diaspar must come and go throughout their endless lives, yet not once in centuries did they echo to the sound of human feet.

Here was 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, according to the maps, the Central Computer brooded eternally over the fate of Diaspar.

The chamber was there, and it was even vaster than Alvin had dared imagine but where was the Computer? Somehow he had expected to meet a single huge machine, naive though he knew that this conception was. The tremendous but meaningless panorama beneath him made him pause in wonder and uncertainty.

The corridor along which they had come 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 that 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 beginnings were 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 new ones took their place. Very slowly, over thousands 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 hundred million years, and in the moment of his triumph he had turned his back upon the machine forever. It had reached finality, and thenceforth could sustain itself eternally while serving him.

Alvin no longer asked himself which of these silent white presences was the Central Computer. He knew that it comprised them all-and that it extended far beyond this chamber, including within its being all the countless other machines in Diaspar, whether they were mobile or motionless. As his own brain was the sum of many billion separate cells, arrayed throughout a volume of space a few inches across, so the physical elements of the Central Computer were scattered throughout the length and breadth of Diaspar. This chamber might hold no more than the switching system whereby all these dispersed units kept in touch with one another.

Uncertain where to go next, Alvin stared down the great sweeping ramps and across the silent arena. The Central Computer must know that he was here, as it knew everything that was happening in Diaspar. He could only wait for its instructions.

The now-familiar yet still awe-inspiring voice was so quiet and so close to him that he did not believe that his escort could also hear it.