“The secret of the dome is merely a matter of understanding space and time and their relationship to black concavities,” Neuronius said. “That relationship is best described in the terms of tensor analysis.”

SilverSide was already familiar with tensor mathematics, quantum mechanics, general relativity, and spacetime physics, which, although more sophisticated in their language and applications, were still the basic sciences developed by Schroedinger and Einstein.

Hyperjump and hyperwave technology were little more than tools that man had discovered quite accidentally and still did not really understand, any more than he understood what an electron was.

So now Neuronius led SilverSide along mathematical pathways dealing with space and time which, familiar at first, became rapidly unfamiliar and bizarre, and twisted his positronic thoughtways in patterns that became ever more uncomfortable.

With that discomfort he began to suspect that Neuronius-if he could twist SilverSide's mind to such a degree-was perhaps superior to Synapo. Certainly Neuronius was different, and maybe it was the difference of a superior mind. He continued to record what Neuronius was saying but stopped generation of associative memory links-stopped listening - inorder to pursue that intriguing comparison of the two aliens. Finally he interrupted Neuronius in his lecture.

“What is a human, Neuronius?”

“What?”

“I have been searching for humans, the beings whose laws govern my behavior. I had thought that humans must be the most intelligent species in the galaxy, but Synapo says Miss Ariel is human, and that he is not, even though he is more intelligent than Miss Ariel.”

Neuronius hesitated. In the silence, the twitter of the jungle birds came to SilverSide, registering with sharp clarity a serenity and tranquillity that was strikingly at odds with the turmoil in his mind.

“I am human,” Neuronius said. “Synapo is not.”

Was there no peace in this life? Unquestionably Neuronius was more intelligent than Miss Ariel, and it seemed more and more apparent that Neuronius was indeed more intelligent than Synapo, yet Synapo was the leader of the Ceremyons. The logical question came immediately to mind.

“Where do you fit into the society of the Ceremyons?”

“I am not a Ceremyon,” Neuronius replied. “I may appear to be so, but I am not. I am far superior to any Ceremyon.”

“Are there others of your kind?”

“Not on this planet. This one is mine. The others each dominate a planet of their own.”

SilverSide was impressed. Yet there was something about Neuronius that bothered him-his wordiness, perhaps; Mandelbrot bothered him that way, but there it was a bother that need not concern him. Mandelbrot was merely a robot. But Neuronius was not a robot, and his words were exceedingly tantalizing, and yet disturbing, uneasily so. Mandelbrot had never made him feel uneasy.

If Neuronius were the only one of his kind on this planet, he had to be the most intelligent being here-if he were indeed more intelligent than Synapo. So he was back to that simple comparison. On balance, Neuronius appeared to be the more intelligent. He had delved far deeper into dome technology than Synapo had during his meeting with the mammals. Synapo had seemed to be withholding information, as though he were not altogether sure of what he was saying. Neuronius certainly did not give that impression. He seemed to be bursting with information. So much so that SilverSide's positronic potentials on the subject of domes were now a complete jumble.

His indecision was excruciating. He had to get the question resolved. He had thought it was resolved, and arriving at that point once again, after having been through it so many times, had been an unsettling experience that he had accepted finally with his imprint on Jacob Winterson. Now all that ordeal seemed to have gone for naught. But how was he to get it resolved?

“I must know who is the more intelligent, you or Synapo. Can you suggest how that can be determined?”

“I am not interested in your petty games, SilverSide. I am offering you knowledge that will allow you to serve whomever you please with greater efficiency. Surely you can see that.”

“But whom I am to serve must clearly be resolved before the service itself can take place. Surely, with your intelligence you can see that.”

“One can train for service quite efficiently without knowing who will ultimately be served.”

“But how one trains-what type of service should be stressed -depends on who will be served.”

That seemed clear to SilverSide, and if Neuronius couldn't understand something as simple as that, he could not be as intelligent as he had at first appeared.

“You are right, of course,” Neuronius said. “But I find it exceedingly distasteful and uncomfortable to promote myself at the expense of others. It makes me appear slow, I suppose. I have no desire to denigrate Synapo.

“You must have this question resolved, must you?” Neuronius said as a small green jet flamed momentarily in the air below his red eyes.

That was one piece of alien body language SilverSide had learned to read. It lent an air of great sincerity to the discomfort Neuronius claimed to feel.

“Yes,” SilverSide said.

“Then you must serve me. I am human, the only human on this planet and the most intelligent of the various species that exist here, and certainly more intelligent than Synapo.”

That must do for the moment. SilverSide could do nothing more immediately. He must try to accept what Neuronius had said, but the acceptance was not something that was going to come easily. He had come to many forks in the path of his quest for humans, and each time-at each crux-the resolution of the dilemma subjected him to more agony.

That conflict, repeated now, and his attempt to cope with it, sent little stabs of pain shooting through his positronic brain, little stabs that congealed into a ball of pure agony, and finally he could bear the pain no longer. He jumped up and fled down the path into the forest while Neuronius's shouts grew fainter and fainter.

Finally exhausted, after Neuronius was left far behind, he stopped. He had left the path and had been plunging through dense vegetation, ripping it out by the roots when it would not yield otherwise. He stood there, recharging his reserve pack. Inthe wild scramble, he had used all the output of his microfusion reactor and more, bleeding his reserves until he was forced to stop.

Then he slowly began to transform from one imprint to the next, trying to find peace of mind, going back from Jacob to Synapo to Wolruf to Derec and finally to KeenEye, to the form in which he had first known being and BeastTongue.

Inthe wolf-like KeenEye imprint, using only a fraction of the output from her reactor, she began loping easily through the forest, finding and following the animal trails that had been created by the natural denizens of Oyster World. She found a measure of peace in the pleasant natural scents left there by those very basic creatures, creatures much lower in the scale of life than LifeCrier, but still so like him in their familiar but dissimilar musky scent.

The night passed as she roamed aimlessly through the Forest of Repose.

Dawn found her at the edge of the forest below The Cliff of Time, back at the trail that led to the clearing where Neuronius had lectured her. The night had served to clarify one thing. She must talk to Synapo again before she could make a final judgment of the humanity of Neuronius.

She could find Synapo by radio, but the only tactful way to talk to him was on the wing. She could not ask him to come to her. He had left the clear impression he did not want to talk to her further. She must go back to the Synapo imprint in order to talk to him on his terms.

When SilverSide finished the transition to blackbody form, the sun was just rising over The Cliff of Time. There was a Ceremyon circling high over the dome in Synapo's accustomed station. SilverSide wobble-hopped into the air and climbed in a long, slanted rise, gaining the necessary altitude to reach the alien in the course of spanning the distance from The Cliff of Time.