“What could that be, though?” Swan said. “What causes that kind of anger?”

“I don’t know… say food, water, land… power… prestige… ideology… differential advantage. Madness. These are the usual motives, aren’t they?”

“I suppose!” She sounded horrified that he could make such a list, as if this were not part of Mercurial discourse, although really it was simply Machiavelli, or Aristotle. Pauline would know the list.

“Anyway,” he went on, “I’ll be very interested to find out what people are saying when we get out of here.”

“Only thirty days to go,” she said grimly.

“One step at a time,” he said gamely.

“Oh please! Take it like that and it’s eternity.”

“Not at all. But I will desist.”

After a while he said, “Interesting how a moment comes when you feel hungry. You didn’t before, and then you do.”

“That’s not interesting.”

“My feet are sore.”

“That’s not interesting either.”

“Each step is a little pain, or every other. Plantar fasciitis, I reckon.”

“Would you like to take a rest?”

“No. They’re only sore, not hurt. And they get warmed up. Then tired.”

“I hate this.”

“And yet here we are.”

The hour of walking passed. The rest period passed. The next hour passed. The rest following that passed. The tunnel stayed always the same. The stations every third night were almost the same, but not quite. They ransacked these places, looking for something different. Up at the top of the elevator shafts in each station lay the surface, exposed to the full Mercurial sun and approaching seven hundred K on surfaces struck by light; there being no air, there was no air temperature. At this point they were under Tolstoi Crater, more or less; Pauline was managing their navigation, such as it was, by a sort of dead reckoning; down here her little radio too was out of touch. The station phones never worked. Swan guessed they were elevator phones only—or else the whole system had broken in the impact, and because of the ongoing situation with Terminator’s population, and the fact that the crushed part of the tunnel was now out in the sun, no one was available to fix it.

Hour after hour they walked. It was easy to lose track of days, particularly since Pauline would keep track. The pseudoiterative was less pseudo than ever. This was the true iterative. Swan walked before Wahram, her shoulders slumped like those of a mime portraying dejection. Minutes dragged until each one felt like ten; it was an exponential expansion of time, a syruping of protraction. They would therefore live ten times as long. He cast about for something to say that would not irritate her. She was muttering at Pauline.

“I used to whistle when I was a kid,” he said, and tried a single tone. His lips felt thicker than they had when he was young. Oh yes—tongue higher against roof of mouth. Very good. “I would whistle the melodies from the symphonies I liked.”

“Whistle, then,” Swan said. “I whistle too.”

“Really!” he said.

“Yes. I told you. But you first. Do you do Beethoven, like what we heard at that concert?”

“I do, kind of. Just some of the tunes.”

“Do that, then.”

There had been a period in Wahram’s youth when every morning had had to begin with Beethoven’s Eroica, the breakthrough Third Symphony, announcement of a new age in music and indeed in the human spirit, written after Beethoven learned that he was going deaf. So Wahram whistled the two commanding notes that started the first movement, and then whistled the main line, at a tempo that fit with his walking pace. That wasn’t so hard to do, somehow. As he whistled along he was never sure he was going to remember the passage that came next, yet by the time he got to the point of change, the next one followed inevitably from it, and flowed from him quite satisfactorily. Somewhere in him these things remained. The sequence of long elaborate melodies flowed one to the next, in just the compelling logic of Beethoven’s own thinking. And this sequence consisted of one stirring inevitable song after another. Most of the passages should have been stranded by counterpoint and polyphonies, and he jumped from one orchestral section to another, depending on which one seemed the main line. But it had to be said that even as single tunes, inexpertly whistled, the magnificence of Beethoven’s music was palpable in the tunnel. The three sunwalkers drifted back, it seemed, to hear it better. After the first movement was over, Wahram found the other three movements came as fully to him as the first, so that by the time he was done, it had taken him about the same forty minutes that an orchestra would have taken with the real thing. The great variations of the finale were so stirring that he almost hyperventilated in the performance of it.

“Wonderful,” Swan said when he was done. “Really good. What tunes. My God. Do more. Can you do more?”

Wahram had to laugh. He thought it over. “Well, I think I could do the Fourth, Fifth, Sixth, Seventh, and Ninth. Also some bits of the quartets and sonatas, maybe. I’d lose the thread in a lot of those, I’m afraid. Maybe not in the late quartets. I’ve lived to those sweet things. I’d have to try and see how it went.”

“How can you remember so many?”

“For a long time that’s all I listened to.”

“That’s crazy. All right, try the Fourth, then. You can take them in order.”

“Later, please. I have to rest. My lips are already destroyed, I can feel them twice as big. They’re like a big old gasket right now.”

She laughed and let him be. An hour later, however, she brought it back up, and sounded like she would be very discouraged if he didn’t do it.

“All right, but you join me,” he said.

“But I don’t know the tunes. I don’t really remember the stuff I hear people play.”

“That doesn’t matter,” Wahram said. “Just whistle. You said you did.”

“I do, but it sounds like this.”

She whistled for a while: a glorious burble of music, exactly like some kind of songbird.

“Wow, you sound just like a bird,” he said. “Very fluid glissandos, and I-don’t-know-whats, but just like a bird.”

“Yes, that’s right. I have some skylark polyps in me.”

“You mean… in your brain? Bird brains, put into your own?”

“Yes. Alauda arvensis.Also some Sylvia borin, the garden warbler. But you know that birds’ brains are organized on completely different lines than mammal brains?”

“No.”

“I thought everyone knew that. Some qube architecture is based on bird brains, so it got discussed for a while.”

“I didn’t know.”

“Well, the thinking that we mammals do in layers of cells across our cortex, birds do in clusters of cells, distributed like bunches of grapes.”

“I didn’t know that.”

“So you can take some of your own stem cells and introduce skylark song node DNA into them, and then you can introduce it through the nose to the brain, and it makes a little cluster in the limbic system. Then when you whistle, the cluster links into your already existing musical networks. All those are very old parts. They’re almost like bird parts of the brain already. So the new ones get hooked in, and off you go.”

“You did this?”

“Yes.”

“How did it feel?”

For answer she whistled. In the tunnel one liquid glissando led to another: bright birdsong, there in the tunnel with them.

“Amazing,” Wahram said. “I didn’t know you could do that. Youshould be the one whistling, not me.”

“You don’t mind?”

“On the contrary.”

So she whistled as they walked along, sometimes for the full hour between breaks. Her burble shifted through all kinds of phases and phrases, and it seemed to Wahram these were so various they must be the songs of more than two species of bird. But he wasn’t sure, as it occurred to him also that she might be as vocally limited by her body as any bird, so these could perhaps be just the variety of songs that a real songbird sang. Glorious music! It was somewhat like Debussy at times, and of course there were Messiaen’s specific imitations of birds; but Swan’s whistling was stranger, more repetitive, with endless permutations of little figures, often repeating in insistent ostinato trills that got their hooks into him, sometimes to the point of irritation.