Yet perhaps her motives were not entirely selfish, and were maternal rather than sexual. Though birth had been forgotten, the feminine instincts of protection and sympathy still remained. Alvin might appear to be stubborn and self-reliant and determined to have his own way, yet Alystra could sense his inner loneliness.

When she found that Alvin had disappeared, she promptly asked Jeserac what had happened to him. Jeserac, with only a momentary hesitation, told her. If Alvin did not want company, the answer was in his own hands. His tutor neither approved nor disapproved of this relationship. On the whole, he rather liked Alystra and hoped that her influence would help Alvin to adjust himself to life in Diaspar.

The fact that Alvin was spending his time at Council Hall could only mean that he was engaged on some research project, and this knowledge at least served to quell any suspicions Alystra might have concerning possible rivals. But though her jealousy was not aroused, her curiosity was. She sometimes reproached herself for abandoning Alvin in the Tower of Loranne though she knew that if the circumstances were re-peated she would do exactly the same thing again. There was no way of understanding Alvin’s mind, she told herself, un-less she could discover what he was trying to do.

She walked purposefully into the main hall, impressed but not overawed by the hush that fell as soon as she passed through the entrance. The information machines were range side by side against the far wall, and she chose one at random.

As soon as the recognition signal lighted up she said, «I am looking for Alvin; he is somewhere in this building. Where can I find him?» Even after a lifetime, one never grew wholly accustomed to the complete absence of time lag when an information ma i chine replied to an ordinary question. There were people w hp knew-or claimed to know-how it was done, and talked, learnedly of «access time» and «storage space,» but that made the final result none the less marvelous. Any question of a 1 purely factual nature, within the city’s truly enormous range of available information, could be answered immediately. Only if complex calculations were involved before a reply could be given would there be any appreciable delay.

«He is with the monitors,» came the reply. It was not very helpful, since the name conveyed nothing to Alystra. No machine ever volunteered more information than it was asked for, and learning to frame questions properly was an art which often took a long time to acquire.

«How do I reach him?» asked Alystra. She would find what the monitors were when she got to them.

«I cannot tell you unless you have the permission of the Council.»This was a most unexpected, even a disconcerting, development. There were very few places in Diaspar that could not be visited by anyone who pleased. Alystra was quite certain that Alvin had not obtained Council permission, and this could only mean that a higher authority was helping him.

The Council ruled Diaspar, but the Council itself could be overridden by a superior power-the all-but-infinite intellect. of the Central Computer. It was difficult not to think of the Central Computer as a living entity, localized in a single spot, though actually it was the sum total of all the machines in Diaspar. Even if it was not alive in the biological sense, it certainly possessed at least as much awareness and self-consciousness as a human being. It must know what Alvin was doing, and, therefore, it must approve, otherwise it would have stopped him or referred him to the Council, as the in-formation machine had done to Alystra.

There was no point in staying here. Alystra knew that any attempt to find Alvin-even if she knew exactly where he was in this enormous building-would be doomed to failure. Doors would fail to open; slideways would reverse when she stood on them, carrying her backward instead of forward; elevator fields would be mysteriously inert, refusing to lift her from one floor to another. If she persisted, she would be gently i conveyed out into the street by a polite but firm robot, or else shuttled round and round Council Hall until she grew fed up and left under her own volition.

She was in a bad temper as she walked out into the street. She was also more than a little puzzled, and for the first time felt that there was some mystery here which made her per-sonal desires and interests seem very trivial indeed. That did not mean that they would be any the less important to her. She had no idea what she was going to do next, but she was sure of one thing. Alvin was not the only person in Diaspar who could be stubborn and persistent.

The image on the monitor screen faded as Alvin raised his hands from the control panel and cleared the circuits. For a moment he sat quite motionless, looking into the blank rec-tangle that had occupied all his conscious mind for so many weeks. He had circumnavigated his world; across that screen had passed every square foot of the outer wall of Diaspar. He knew the city better than any living man save perhaps IChe-dron; and he knew now that there was no way through the walls.

The feeling that possessed him was not mere despondency; be had never really expected that it would be as easy as this, that he would find what he sought at the first attempt. What was important was that he had eliminated one possibility. Now he must deal with the others.

He rose to his feet and walked over to the image of the city which almost filled the chamber. It was hard not to think of it as an actual model, though he knew that in reality it was no more than an optical projection of the pattern in the memory cells he had been exploring. When he altered the monitor controls and set his viewpoint moving through Dias-par, a spot of light would travel over the surface of this rep-lica, so that he could see exactly where he was going. It had been a useful guide in the early days, but he soon had grown so skillful at setting the co-ordinates that he had not needed this aid.

The city lay spread out beneath him; he looked down upon it like a god. Yet he scarcely saw it as he considered, one by one, the steps he should now take.

If all else failed, there was one solution to the problem. Diaspar might be held in a perpetual stasis by its eternity circuits frozen forever according to the pattern in the memory cells, but that pattern could itself be altered, and the city would then change with it. It would be possible to redesign a section of the outer wall so that it contained a doorw feed this pattern into the monitors, and let the city resh itself to the new conception.

Alvin suspected that the large areas of the monitor control board whose purpose Khedron had not explained to him concerned with such alterations. It would be useless to periment with them; controls that could alter the very structure of the city were firmly locked and could be operated only with the authority of the Council and the approval the Central Computer. There was very little chance that Council would grant him what he asked, even if he was prepared for decades or even centuries of patient pleading. This was not a prospect that appealed to him in the least.

He turned his thoughts toward the sky. Sometimes he imagined, in fantasies which he was half-ashamed to recall that he had regained the freedom of the air which man h renounced so long ago. Once, he knew, the skies of Earth ha been filled with strange shapes. Out of space the great ships had come, bearing unknown treasures, to berth at the legendary Port of Diaspar. But the Port had been beyond the limits of the city; aeons ago it had been buried by the drifting sand He could dream that somewhere in the mazes of Diaspar flying machine might still be hidden, but he did not really lieve it. Even in the days when small, personal flyers had bee in common use, it was most unlikely that they had ever be 1 allowed to operate inside the limits of the city.