I followed a false lead to Calexico, went back to Brawley, started over, picked it up again, and traced them as far as Yutna.

At Yuma I gave up the chase, for Ricky had gotten married. What I saw on the register at the county clerk's office there shocked me so much that I dropped everything and jumped a ship for Denver, stopping only to mail a card to Chuck telling him to clear out my desk and pack the stuff in my room.

I stopped in Denver just long enough to visit a dental-supply house. I had not been in Denver since it had become the capital-after the Six Weeks War, Miles and I had gone straight to California-and the place stunned me. Why, I couldn't even find Colfax Avenue. I had understood that everything essential to the government was buried back under the Rockies. If that is so, then there must be an awful lot of nonessentials still aboveground the place seemed even more crowded than Great Los Angeles.

At the dental-supply house I bought ten kilograms of gold, isotope 197, in the form of fourteen-gauge wire. I paid $86.10 a kilogram for it, which was decidedly too much, since gold of engineering quality was selling for around $70 a kilogram, and the transaction mortally wounded my only thousand-dollar bill. But engineering gold comes either in alloys never found in nature, or with isotopes 196 and 198 present, or both, depending on the application. For my purposes I wanted fine gold, undetectable from gold refined from natural ore, and I did not want gold that might burn my pants off if I got cozy with it-the overdose at Sandia had given me a healthy respect for radiation poisoning.

I wound the gold wire around my waist and went to Boulder. Ten kilograms is about the weight of a well-filled weekend bag and that much gold bulks almost exactly the same as a quart of milk. But the wire form of it made it bulk more than it would have solid; I can't recommend it as a girdle. But gold slugs would have been still harder to carry, and this way it was always with me.

Dr. Twitchell was still living there, though no longer working; he was professor emeritus and spent most of his waking hours in the bar of the faculty club. It took me four days to catch him in another bar, since the faculty club was closed to outlanders like me. But when I did, it turned out to be easy to buy him a drink.

He was a tragic figure in the classic Greek meaning, a great man-a very great man-gone to ruin. He should have been up there with Einstein and Bohr and Newton; as it was, only a few specialists in field theory were really aware of the stature of his work. Now when I met him his brilliant mind was soured with disappointment, dimmed with age, and soggy with alcohol. It was like visiting the ruins of what had been a magnificent temple after the roof has fallen in, hail the columns knocked down, and vines have grown over it all.

Nevertheless, he was brainier on the skids than I ever was at my best. I'm smart enough myself to appreciate real genius when I meet it.

The first time I saw him he looked up, looked straight at me and said, "You again."

"Sir?"

"You used to be one of my students, didn't you?"

"Why, no, sir, I never had that honor." Ordinarily when people think they have seen me before, I brush it off; this time I decided to exploit it if I could. "Perhaps you are thinking of my cousin, DoctorÄclass of `86. He studied under you at one time."

"Possibly. What did he major in?"

"He had to drop out without a degree, sir. But he was a great admirer of yours. He never missed a chance to tell people he had studied under you."

You can't make an enemy by telling a mother her child is beautiful. Dr. Twitchell let me sit down and presently let me buy him a drink. The greatest weakness of the glorious old wreck was his professional vanity. I had salvaged part of the four days before I could scrape up an acquaintance with him by memorizing everything there was about him in the university library, so I knew what papers he had written, where he had presented them, what earned and honorary degrees he held, and what books he had written. I had tried one of the latter, but I was already out of my depth on page nine, although I did pick up a little patter from it.

I let him know that I was a camp follower of science myself; right at present I was researching for a book: Unsung Geniuses.

"What's it going to be about?"

I admitted diffidently that I thought it would be appropriate to start the book with a popular account of his life and works, provided he would be willing to relax a bit from his well-known habit of shunning publicity. I would have to get a lot of my material from him, of course.

He thought it was claptrap and could not think of such a thing. But I pointed out that he had a duty to posterity and he agreed to think it over. By the next day he simply assumed that I was going to write his biography-not just a chapter, a whole book. From then on he talked and talked and I took notes... real notes; I did not dare try to fool him by faking, as he sometimes asked me to read back.

Finally I said, "Doctor, isn't it true that if it had not been for a certain colonel who was once stationed here you would have had the Nobel Prize hands down?"

He cursed steadily for three minutes with magnificent style. "Who told you about him?"

"Uh, Doctor, when I was doing research writing for the Department of Defense--I've mentioned that, haven't I?"

"No."

"Well, when I was, I heard the whole story from a young Ph.D. working in another section. He had read the report and he said it was perfectly clear that you would be the most famous name in physics today... if you had been permitted to publish your work."

"Hrrmph! That much is true."

"But I gathered that it was classified... by order of this Colonel, uh, Plushbottom."

"Thrushbotham. Thrushbotham, sir. A fat, fatuous, flatulent, foot-kissing fool incompetent to find his hat with it nailed to his head. Which it should have been."

"It seems a great pity."

"What is a pity, sir? That Thrushbotham was a fool? That was nature's doing, not mine."

"It seems a pity that the world should be deprived of the story. I understand that you are not allowed to speak of it."

"Who told you that? I say what I please~"

"That was what I understood, sir... from my friend in the Department of Defense."

"Hrrrmph!"

That was all I got Out of him that night. It took him a week to decide to show me his laboratory.

Most of the building was now used by other researchers, but his time laboratory he had never surrendered, even though he did not use it now; he fell back on its classified status and refused to let anyone else touch it, nor had he permitted the apparatus to be torn down. When he let me in, the place smelled like a vault that has not been opened in years.

He had had just enough drinks not to give a damn, not so many but what he was still steady. His capacity was pretty high. He lectured me on the mathematics of time theory and temporal displacement (he didn't call it "time travel"), but he cautioned me not to take notes. It would not have helped if I had, as he would start a paragraph with, "It is therefore obvious-" and go on from there to matters which may have been obvious to him and God but to no one else.

When he slowed down I said, "I gathered from my friend that the one thing you had not been able to do was to calibrate it? That you could not tell the exact magnitude of the temporal displacement?"

"What? Poppycock! Young man, if you can't measure it, it's not science." He bubbled for a bit, like a teakettle, then went on, "Here. I'll show you." He turned away and started making adjustments. All that showed of his equipment was what he called the "temporal locus stage"-just a low platform with a cage around it-and a control board which might have served for a steam plant or a low-pressure chamber. I'm fairly sure I could have studied out how to handle the controls had I been left alone to examine them, but I had been told sharply to stay away from them. I could see an eight-point Brown recorder, some extremely heavy-duty solenoid-actuated switches, and a dozen other equally familiar components, but it didn't mean a thing without the circuit diagrams.