If there was one subject about which Eternals were almost superstitious, it was the "Hidden Centuries," the time between the 70,000th and the 150,000th. It was a subject that was rarely mentioned. It was only Harlan's close association with Twissell that accounted for his own small knowledge of the era. What it amounted to was that Eternals couldn't pass into Time in all those thousands of Centuries. The doors between Eternity and Time were impenetrable. Why? No one knew.

Harlan imagined, from some casual remarks of Twissell's, that attempts had been made to Change the Reality in the Centuries just downwhen from the 70,000th, but without adequate Observation beyond the 70,000th not much could be done.

Twissell had laughed a bit one time and said, "We'll get through someday. Meanwhile, 70,000 Centuries is quite enough to take care of."

It did not sound wholly convincing.

"What happens to Eternity after the 150,000th?" asked Cooper.

Harlan sighed. The subject, apparently, was not to be changed. "Nothing," he said. "The Sections are there but there are no Eternals in it anywhere after the 70,000th. The Sections keep on going for millions of Centuries till all life is gone and past that, too, till the sun becomes a nova, and past that, too. There isn't any end to Eternity. That's why it's called Eternity."

"The sun does become a nova, then?"

"It certainly does. Eternity couldn't exist if that weren't so. Nova Sol is our power supply. Listen, do you know how much power is required to set up a Temporal Field? Mallansohn's first Field was two seconds from extreme downwhen to extreme upwhen and big enough to hold not more than a match head and that took a nuclear power plant's complete output for one day. It took nearly a hundred years to set up a hair-thin Temporal Field far enough upwhen to be able to tap the radiant power of the nova so that a Field could be built big enough to hold a man."

Cooper sighed. "I wish they would get to the point where they stopped making me learn equations and field mechanics and start telling me some of the interesting stuff. Now if I had lived in Mallansohn's time--"

"You would have learned nothing. He lived in the 24th, but Eternity didn't start till late in the 27th. Inventing the Field isn't the same as constructing Eternity, you know, and the rest of the 24th didn't have the slightest inkling of what Mallansohn's invention signified."

"He was ahead of his generation, then?"

"Very much so. He not only invented the Temporal Field, but he described the basic relationships that made Eternity possible and predicted almost every aspect of it except for the Reality Change. Quite closely, too-but I think we're pulling to a halt, Cooper. After you."

They stepped out.

Harlan had never seen Senior Computer Laban Twissell angry before. People always said that he was incapable of any emotion, that he was an unsouled fixture of Eternity to the point where he had forgotten the exact number of his homewhen Century. People said that at an early age his heart had atrophied and that a hand computer similar to the model he carried always in his trouser pocket had taken its place.

Twissell did nothing to deny these rumors. In fact most people guessed that he believed them himself.

So even while Harlan bent before the force of the angry blast that struck him, he had room in his mind to be amazed at the fact that Twissell could display anger. He wondered if Twissell would be mortified in some calmer aftermath to realize that his hand-computer heart had betrayed him by exposing itself as only a poor thing of muscle and valves subject to the twists of emotion.

Twissell said, in part, his old voice creaking, "Father Time, boy, are you on the Allwhen Council? Do you give the orders around here? Do you tell me what to do or do I tell you what to do? Are you making arrangements for all kettle trips this Section? Do we all come to you for permission now?"

He interrupted himself with occasional exclamations of "Answer me," then continued pouring more questions into the boiling interrogative caldron.

He said finally, "If you ever get above yourself this way again, I'll have you on plumbing repair and for good. Do you understand me?"

Harlan, pale with his own gathering embarrassment, said, "I was never told that Cub Cooper was not to be taken on the kettle."

The explanation did not act as an emollient. "What kind of an excuse is a double negative, boy? You were never told not to get him drunk. You were never told not to shave him bald. You were never told not to skewer him with a fine-edged Tav curve. Father Time, boy, what were you told to do with him?"

"I was told to teach him Primitive history."

"Then do so. Do nothing more than that." Twissell dropped his cigarette and ground it savagely underfoot as though it were the face of a lifelong enemy.

"I'd like to point out, Computer," said Harlan, "that many Centuries under the current Reality somewhat resemble specific eras of Primitive history in one or more respects. It had been my intention to take him out to those Times, under careful spatio-temporal charting, of course, as a form of field trip."

"What? Listen, you chucklehead, don't you ever intend to ask my permission for anything? That's out. Just teach him Primitive history. No field trips. No laboratory experiments, either. Next you'll be changing Reality just to show him how."

Harlan licked his dry lips with a dry tongue, muttered a resentful acquiescence, and, eventually, was allowed to leave.

It took weeks for his hurt feelings to heal over somewhat.

Harlan had been two years a Technician when he re-entered the 482nd for the first time since leaving with Twissell. He found it almost unrecognizable.

It had not changed. He had.

Two years of Technicianhood had meant a number of things. In one sense it had increased his feeling of stability. He had no longer to learn a new language, get used to new styles of clothing and new ways of life with every new Observation project. On the other hand, it had resulted in a withdrawal on his own part. He had almost forgotten now the camaraderie that united all the rest of the Specialists in Eternity.

Most of all, he had developed the feeling of the power of being a Technician. He held the fate of millions in his finger tips, and if one must walk lonely because of it, one could also walk proudly.

So he could stare coldly at the Communications man behind the entry desk of the 482nd and announce himself in clipped syllables: "Andrew Harlan, Technician, reporting to Computer Finge for temporary assignment to the 482nd," disregarding the quick glance from the middle-aged man he faced.

It was what some people called the "Technician glance," a quick, involuntary sidelong peek at the rose-red shoulder emblem of the Technician, then an elaborate attempt not to look at it again.

Harlan stared at the other's shoulder emblem. It was not the yellow of the Computer, the green of the Life-Plotter, the blue of the Sociologist, or the white of the Observer. It was not the Specialist's solid color at all. It was simply a blue bar on white. The man was Communications, a subbranch of Maintenance, not a Specialist at all.

And he gave the "Technician glance" too.

Harlan said a little sadly, "Well?"

Communications said quickly, "I'm ringing Computer Finge, sir."

Harlan remembered the 482nd as solid and massive, but now it seemed almost squalid.

Harlan had grown used to the glass and porcelain of the 575th, to its fetish of cleanliness. He had grown accustomed to a world of whiteness and clarity, broken by sparse patches of light pastel.