Not far from the mission was the cavern of the night birds, where the dead lived. Because of the old legends, the natives refused to go with them. It took a lot of persuasion before two monks and an Indian would come along. It was one of the longest caverns on the continent, a hole sixty feet by ninety which let in so much light that for the first hundred and fifty feet inside the rock, there was grass underfoot and treetops overhead. Only after that did they need to light torches. This was also where the screaming began.

  The darkness was home to birds. Thousands of nests hung from the roof like pouches, and the noise was deafening. How they navigated was a mystery. Bonpland fired three shots which were drowned out by the screeching, and immediately picked up two bodies, still twitching. Humboldt hammered samples of stone out of the rock, measured temperature, air pressure, and relative dampness, and scratched moss off the wall. A monk cried out as his sandal squashed a huge unprotected snail. They had to wade through a stream as the birds fluttered around their heads, and Humboldt pressed his hands over his ears while the monks made the sign of the cross.

  Here, said the guide, was where the kingdom of the dead began. This was as far as he would go.

  Humboldt offered to double his pay.

  The guide declined. This place was no good! And besides, what were they looking for here; men belonged in the light.

  Well said, roared Bonpland.

  Light, yelled Humboldt, light wasn't brightness, light was knowledge!

  He went on, and Bonpland and the monks followed. The passage divided, and without a guide they didn't know which way to go. Humboldt suggested they split up. Bonpland and the monks shook their heads.

  Then left, said Humboldt.

  Why left, said Bonpland.

  Well then, right, said Humboldt.

  But why right?

  Dammit, yelled Humboldt, this was becoming really stupid. And he went left, ahead of the others. The screaming of the birds echoed even louder down here. After a time it was possible to make out high-pitched clicking sounds, produced one after the other at great speed. Humboldt knelt down to inspect the misshapen plants on the cave floor. Bloated, colorless growths, almost formless. Interesting, he shouted in Bonpland's ear, he had written a paper in Freiberg about exactly this!

  When the two of them looked up, they noticed that the monks were no longer there.

  Superstitious blockheads, cried Humboldt. Onward!

  The ground sloped sharply downhill. They were surrounded by the clattering of wings, yet no creature ever brushed against them. They groped their way along a wall to a rock cathedral. The torches, too feeble to illuminate the vault, threw exaggerated shadows onto the walls. Humboldt looked at the thermometer: it was getting steadily warmer, he doubted Professor Werner would be pleased! The next thing he saw was the figure of his mother, standing next to him. He blinked, but she remained visible for longer than was appropriate for an illusion. Her shawl tied tight against her throat, head to one side, smiling absentmindedly chin and nose as thin as they had been on the last day of her life, a bent umbrella in her hands. He closed his eyes and counted slowly to ten.

  What did you say, asked Bonpland.

  Nothing, said Humboldt, and concentrated on hammering a splinter out of the stone.

  Further back there, the passage continued, said Bonpland.

  They'd done enough, said Humboldt.

  Bonpland offered up that there must surely be more unknown plants deeper inside the mountain.

  Better to turn back, said Humboldt. Enough was enough.

  They followed a stream in the direction of the sunlight. Gradually the number of birds diminished, their screaming quieted, and soon they could extinguish the torches.

  In front of the cave mouth the Indian guide was turning their two birds over a fire to render the fat. The feathers, beaks, and necks were already scorched, blood was dripping into the flames, the fatty tissue was hissing, and a bigger smoke hung over the clearing. The best fat, he explained. Odorless, and it would stay fresh for more than a year.

  Now they would need two more, said Bonpland, furious.

  Humboldt asked Bonpland for his brandy flask, took a big swallow, and set off on the path back to the mission with one of the monks, while Bonpland returned the other way to shoot two more birds. After several hundred yards, Humboldt stopped still, tilted his head back, and looked up into the tree-tops which were holding up the sky high above his head.

  Reverberation!

  Reverberation, repeated the monk.

  If it wasn't a sense of smell, said Humboldt, it must be the resonance. That clicking, echoing back off the walls. That must be how the creatures worked out their direction.

  As he went on, he made notes. A system that people could utilize on moonless nights or underwater. And the fat: its odor-lessness would make it ideal for manufacturing candles. He threw open the door to his monastery cell, and a naked woman was there waiting for him. At first he thought either she was there because of the lice, or she'd brought a message. Then he understood that this time it wasn't the case, and she wanted exactly what he thought she wanted, and that there was no way out.

  Obviously the governor had sent her, it fit with his idea of a rough joke between men. She had been waiting alone in the room for a night and a day, out of sheer boredom she'd taken the sextant to pieces and muddled up all the collected plants, drunk the spirits intended for the preparation of specimens, and then slept off her drunkenness. After waking up she'd found a funny portrait of a dwarf with pursed lips, which she naturally failed to recognize as Frederick the Great, and colored it in quite well. Now that Humboldt was finally here, she wanted to get it over with.

  While he was still asking where she'd come from, what she wanted, and if there was anything he could do for her, she was already undoing his trousers with a practiced hand. She was small and plump and couldn't be much older than fifteen. He moved backwards, she followed him, he bumped against the wall and as he tried sharply to set her straight, he found he'd forgotten his Spanish.

  Her name was Ines, she said, and he could trust her.

  As she pulled up his shirt, a button tore off and rolled across the floor. Humboldt followed it with his eyes until it hit the wall and fell over. She put her arms round his neck and pulled him, while he murmured that she was to let go, he was an official of the Prussian Crown, into the middle of the room.

  Oh God, she said, listen to your heart pound.

  She dragged him down with her onto the carpet, and for some reason he allowed her to roll him onto his back while her hands wandered down over him until she stopped, laughed, and said there wasn't much going on. He looked at her bent back, the ceiling, and the palm leaves shivering in the wind outside the window.

  Now, she said. He was to trust her!

  The leaves were short and pointed, it was a tree he had never inspected until now. He wanted to sit up, but she laid her hand on his face and pushed him down, and he asked himself how she could fail to understand that he was in hell. Later on he couldn't have said how long it lasted before she gave up, pushed back her hair, and looked at him sadly. He closed his eyes. She stood up.

  It didn't matter, she said quietly, it was her fault.

  His head hurt, and he had a raging thirst. Only when he heard the door shut behind her did he open his eyes.

  Bonpland found him at his desk, surrounded by the chronometers, the hygrometer, the thermometer, and the reassembled sextant. Magnifying glass clenched in his eye, he was looking at palm leaves. Interesting structure, remarkable! It was getting to be time they moved on.

  So suddenly?

  According to old reports, there was a natural channel between the great rivers of the Orinoco and the Amazon. European geographers took that to be mere legend. The dominant school of theory held that only mountain ranges could act as watersheds, and there was no possible linkage between inland river systems.

  Oddly enough, he had never thought about it, said Bonpland.

  The the
ory was wrong, said Humboldt. He was going to find the channel and solve the riddle.

  Aha, said Bonpland. A channel.

  He didn't like his attitude, said Humboldt. Always complaining, always objecting. Would it be too much to ask for a little enthusiasm?

  Bonpland asked if something had happened.

  There was about to be an eclipse of the sun! This would enable him to establish the exact coordinates of their coastal town. Then it would be possible to construct a net of measuring points all the way to the end of the channel.

  But that would be way deep in primeval forest!

  Primeval was a big word, said Humboldt. It shouldn't be allowed to frighten him. Primeval forest was still just forest. Nature spoke the same language everywhere.

  He wrote to his brother. The journey was magnificent, with a plethora of discoveries. New plants cropped up every day, more than one could count, and his observations of tremors were suggesting a new theory of the earth's crust. His knowledge of the nature of head lice was also becoming unusually advanced. Yours as always, please put this in the newspaper!

  He checked to see if his hand was still trembling. Then he wrote to Immanuel Kant. A new concept of the science of physical geography was forcing its way into his mind. At different altitudes, although at similar temperatures, similar plants grew all over the planet, so climate zones stretched not just laterally but also vertically: at some given spot the earth's surface could thus run the gamut from tropical to arctic. If one connected these zones into lines, one would get a map of the major climate currents. Thanking him for any comments, and in warmest hopes that the professor was in good health, he remained his humble … He closed his eyes, inhaled deeply, and signed with the boldest signature he could muster.

  The day before the eclipse something unpleasant occurred. As they were taking air pressure measurements down on the beach, a Zambo, part black, part Indian, leapt out of the bushes clutching a wooden club. He growled, hunched his body, stared, and then attacked. An unhappy accident, Humboldt called it, as he wrote his account by flickering candlelight at around 3 a.m. some days later on board ship to Caracas in a wild sea. He had ducked left away from the blow, but Bon-pland on his right had not been so lucky. But as Bonpland remained lying motionless on the ground, the Zambo missed his opportunity; instead of going for Bonpland again, he had chased after Bonpland's hat as it flew off, and strode away while putting it on his head.

  At least no damage to the instruments was incurred and even Bonpland came to after twenty hours: face swollen, one lost tooth, the shape of his nose somewhat altered, and dried blood around mouth and chin. Humboldt, who had been sitting by his bed through the evening, night, and long hours of the morning, handed him some water. Bonpland washed himself, spat, and looked mistrustfully into the mirror.

  The eclipse of the sun, said Humboldt. Would he manage?

  Bonpland nodded.

  Was he sure?

  Bonpland spat and said thickly that he was sure.

  Great days were coming, said Humboldt. From the Orinoco to the Amazon. Into the heart of the interior. Bonpland must give him his hand!

  With great effort, as if pushing against some force of resistance, Bonpland raised his arm.

  At the predicted time in the afternoon, the sun was extinguished. The light faded, a swarm of birds flew up into the air, screeching, and swooped away, objects seemed to absorb the brightness, a shadow fell across them, and the ball of the sun became a dark curve. Bonpland, head bandaged, held the screen of the artificial horizon. Humboldt set up the sextant on it, and used the other eye to squint at the chronometer. Time stood still.

  And started to move again. The light returned. The ball of the sun emitted rays again, the shadow detached itself from the hills, the earth, then the horizon. Birds called, someone somewhere fired a shot. Bonpland let down the screen.

  Humboldt asked what it had been like.

  Bonpland stared at him in disbelief.

  He hadn't seen any of it, said Humboldt. Only the projection. He had had to fix the constellations in the sextant and also track the exact time. There had been no time to look up.

  There wouldn't be a second chance, said Bonpland hoarsely. Had he really not looked up?

  This place was now fixed forever in the maps of the world. There were only ever a few moments in which one could use the sky to correct clock time. Some people took their work more seriously than others!

  That could well be, but … Bonpland sighed.

  Yes? Humboldt leafed in the astronomical almanac, took up his pencil, and began to calculate. So what was it now?

  Did one always have to be so German?

  NUMBERS

  On the day everything changed, one of his molars was hurting so much he thought he'd go insane. In the night he had lain on his back, listening to the landlady snoring next door. At about six thirty in the morning, as he blinked wearily into the dawn light, he discovered the solution to one of the oldest problems in the world.

  He went staggering through the room like a drunk. He must write it down immediately, he must not forget it. The drawer didn't want to open, suddenly the paper had hidden itself from him, his quill broke off and made blotches, and then the next thing to trip him up was the chamber pot. But after half an hour of scribbling there it all was on some crumpled piece of paper, the margins of a Greek textbook, and the tabletop. He laid his pen aside. He was breathing heavily. He realized that he was naked, and registered the dirt on the floor and the stink with surprise. He was freezing. His toothache was almost unbearable.

  He read. Worked his way through it, followed the proof line by line, looked for errors, and didn't find any. He roamed over the last page and looked at his distorted, smeared, seventeen-sided figure. For more than two thousand years, people had been constructing regular triangles and pentangles with ruler and compasses. To construct a square or to double the angles of a polygon was child's play. And if one combined a triangle and a pentangle, what one got was a fifteen-sided figure. More was impossible.

  And now: seventeen. And he had a hunch there was a method that would allow him to go further. But he would have to find it.

  He went to the barber, who tied his hands tight, promised it really wouldn't be bad, and with one quick movement pushed his pincers into his mouth. The very touch of them, a blinding flash of pain, almost made him faint. He tried to gather his thoughts, but then the pincers took hold, something went click in his head, and it was the taste of blood and the pounding in his ears that brought him back to the room and the man with the apron, who was saying it hadn't been so bad, had it?

  On his way home he had to lean against walls, his knees were weak, his feet weren't under control, and he felt dizzy. In another few years there would be doctors for teeth, then it would be possible to cure this kind of pain and you wouldn't have to have every inflamed tooth pulled. Soon the world would no longer be full of the toothless. And everybody wouldn't have pockmarks, and nobody would lose their hair. He was amazed that nobody else ever thought about these things. People thought everything was naturally the way it was. Eyes glazed, he made his way to Zimmerman's rooms.

  Entering without knocking, he laid the pieces of paper out in front of him on the dining table.

  Oh, said the professor sympathetically, teeth, bad? He himself had been lucky, he'd only lost five, Professor Lichtenberg was left with a mere two, and Kästner had been toothless for years. With the tips of his fingers, because of a bloodstain, he picked up the first sheet. His brow furrowed. His lips moved.It went on so long that Gauss could hardly believe it any more. Nobody could take that long to think!

  This is a great moment, said Zimmerman finally.

  Gauss asked for a glass of water.

  He felt like praying. This must be printed, and it would be best if it appeared under the name of a professor. It wasn't the done thing for students to be publishing on their own.

  Gauss tried to reply, but when Zimmerman brought him the glass of water, he could n
either speak nor drink. He made a gesture of apology, wobbled home, lay down in bed, and thought about his mother up there in Brunswick. It had been a mistake to come to Göttingen. The university here was better, but he missed his mother, and even more so when he was ill. At about midnight, when his cheek had swollen still further and every movement in every part of his body hurt, he realized the barber had pulled the wrong tooth.

  Luckily the streets were still empty in the early morning so nobody saw him stopping continually to lean his head against the house walls and sob. He would have given his soul to live a hundred years later when there would be medications for pain and doctors who deserved the name. Nor was it that hard. All that was necessary was to numb the nerves in the right spot, the best thing would be little doses of poison. Curare needed to be researched better! There was a flask of it in the Institute of Chemistry, he would go and have a look. But his thoughts slid away from him and he was only more aware of his own groaning.

  It happens, said the barber cheerfully. Pain spread itself wide, but Nature was intelligent and man came with plenty of teeth. At the moment when he pulled the tooth, everything around Gauss went black.

  As if the pain had wiped the event from his memory or from time itself, he found himself hours or days later—how could he tell—back in the chaos of his bed, with a half-empty bottle of schnapps on the night table and at his feet the Universal Advertiser and Literary Supplement, in which Privy Councilor Zimmerman laid out the latest method for constructing a regular seventeen-sided figure. And sitting beside the bed was Bartels, who had come to congratulate him.