On the way I pa.s.sed a lorry carrying timber down from the hills. There were steel chutes like the one by Mackellar's field all round these parts. A trio of foresters sat on the long logs on top of the lorry, the wind fluttering their hair and the green fabric of their overalls. When I got home, night had fallen. All along the Holy Loch, searchlights were probing long fingers of light across the water.

Ten.

'Home', of course, was the cot-house in the field. Throat wooden, head buzzing from the beer, I threw myself onto the bed. As the clouds pa.s.sed over the moon up beyond my uncurtained window, I thought of Lev the sea lion, Habakkuk the prophet-and again of Ryman, that other prophet whom I had not yet met.

Through the window's film of moisture I watched the blue-grey clouds perform their intermittent veiling of the moon-restlessly gleaming and quivering, sometimes seeming to streak the darkness, sometimes to be streaked with it.

Lying there, staring at that deceptive dance of light and shade, my thoughts pa.s.sed to my own old home...How once my mother had opened the door to our holiday cottage on Zomba mountain and a snake had shot out from under the draughtdust-excluder-some piece of vulcanised rubber, scuffed leather, something, nailed to the bottom of the rickety old door. Our dog Vickers chased off in pursuit.

There is a snake in every childhood. But mostly we had happy times. At harvest time I liked nothing more as a young boy than going to the tobacco auctions in Blantyre with my father, watching the great yellow bales he had grown and gathered being unloaded and sold. The auctioneers were mostly South Africans or Rhodesians. As they talked the prices up and down in the argot of the auction room, it was like listening to a strange music.

Once the sales were over we would go to the club in Limbe and I would drink a gla.s.s of squash while father had whisky and soda with his chums, their talk largely of the turn of the tobacco, which was not its curling leaf but the difference between the buying and selling price, and who would win next month's cup at the races over in Salisbury. In those days people travelled about Rhodesia, Northern and Southern, and Nyasaland itself as if they were a single country.

There were wooden ceiling fans spinning as these discussions took place, moving the air around us. I remember these made a big impression on me. I wonder sometimes if they were the source of my interest in turbulence, but that probably had much more to do with the African weather-something emerging darkly from the ap.r.o.n of stirring cloud which tumbled off the edge of Zomba mountain plateau. Zomba and Mulanje are Nyasaland's two great mountains. We visited both, to get away from the flat expanses of tobacco fields near Kasungu, and to escape the heat.

In later years, as the tobacco price rose, my father could afford to buy a cottage on Zomba. It was a green-painted building hidden halfway up the mountain in a grove of tall trees. What I remember most fondly is the preparation to go there, back in Kasungu, the antecedent excitement of my mother packing cardboard boxes with provisions, my father putting bullets into the magazine of a hunting rifle, or preparing his fishing flies for the trout streams. There was water everywhere on Zomba. It was like a giant scoop or sponge sucking down the storms that pressed up from Lake Nyasa, with thousands of trickles and streams running through the forest, keeping everything in a luxuriant, dark-green harmony.

Other times we would go to Nkhotakhota, or Monkey Bay, and other places along the long strip of Lake Nyasa itself. It was called the calendar lake because it was 356 miles long and 52 miles wide. Sometimes we used to travel on a dented white steamer called the Ilala Ilala, which carried pa.s.sengers and cargo up and down the kingfisher-blue expanse.

On one voyage to Monkey Bay, Vickers went crazy, leaping off the ship into the water in pursuit of some goats and chickens that were being unloaded into canoes. Rhodesian ridge-backs are good swimmers, and ours swam all the way to the sh.o.r.e and disappeared. With the help of some good-natured fishermen who were sitting cross-legged mending their nets, we eventually found him at sunset, running about on the sand with piebald dogs from the villages. They were all barking and jumping over each other, as if they had gathered for a celebration. The image has always stuck in my memory.

There were often waterspouts on Lake Nyasa-vast moving pillars of air and water whirling about a low-pressure core. They seem like divine manifestations but share, scientifically speaking, the characteristics of both the tornado that wreaks such violence in the United States and the street eddy that in cities across the world turns up leaves and dust and paper into a recognisable column. I could watch such visitations all day-they are hypnotic-but the event which was to determine my future interest in weather took place, as I say, in Zomba, in 1931. I was fifteen years old, and the first I knew of it was Vickers barking outside, followed by a sound in the distance, like a waterfall. Then one of my mother's pickle jars trembled on a shelf in the cottage, before falling to the stone floor and smashing. I realised there was something wrong with the light coming in through the window.

Both my parents were outside in the garden. My mother was tending her flowerbeds: she loved a flower called the ixia, which had white petals with a prominent dark-purple streak in the middle. It was sweetly scented, particularly in the evenings. Nearby where she knelt, trowel in hand, my father-hair slicked back with Brylcreem, pipe in his mouth-was doing his accounts on a rickety old table.

I suppose, until he lifted his head, Vickers was curled up next to the table. He usually was, now and then rising to stretch in the sun, allowing my father to reach down and ruffle the peculiar line of fur that ran up his spine-against the grain of the rest of his coat-and gave his breed its name.

"Jolly good fellow," my father used to say, whenever he patted him on the furline like that.

I stared at the smashed jar, then ran outside, ducking back into the stone recess of the porch as soon as I saw the vast wall of mud bearing down the mountainside. Darkening the fall of light, it was simply roaring towards us and nothing-nothing!-was going to stop that. I watched as, twenty feet away, my parents, the one still kneeling in front of her ixias, the other throwing back his chair as he suddenly stood up, were trapped by the waves of mud. There was no chance of them getting to me, though they tried; it all came down too quickly. A chunk of masonry from the cottage fell off near me and I pretty much resigned myself to dying in the mudslide.

But I didn't. Instead I watched my parents drown in it: half a million tonnes of clay mixed with water which slid down Zomba that day, slumping from an area of felled plantation forest after a flash flood from a river. Liquefied mud, thick, rocky mud, mud spilling down a hillside and over your loved ones as if it were chocolate. Coating their skin, covering their hair, filling their lungs.

n.o.body wants to remember that-your parents rearing like tethered horses as they try to reach you-and I have tried to cover over the event in my memory. So completely that sometimes I am persuaded that I did not actually witness it, that I pa.s.sed out and have imagined the whole thing retrospectively. I have no idea what happened to Vickers: I know I heard the bark beforehand, and I know he was, or would have been, sitting at my father's feet; but after that not a glimpse, not a sound. Nothing but mud.

So far as verifiable facts go, I do not even know how I was rescued, only that I was removed by the colonial authorities to an orphanage at Cape Town in South Africa. From there a cousin of my mother's took me on, paying for my continuing education at Douai in Berkshire and later funding me at Cambridge.

Laminar flow and whirling flow, I had seen in a single terrible instance the regular predictable straightness of the one and the viscous, unpredictable evolution of the other. I had also experienced difficulties relating to the vantage-point of an observer: that positionality in time and s.p.a.ce which, along with the two types of flow, is central to fluid dynamics.

What I hadn't understood, except in the most immediate and tearful sense of personal bereavement, was the full human dimension: how the event would distort my perceptions of-and relations with-others. How it turned me into this inward, unreflexive creature, this truculent, obtuse, curly-haired character I now look askance at in the mirror in my cabin on the Habbakuk Habbakuk, lifting my head from the page.

Of course, the hair is white now, whereas once it was dark. The blank paper too, it strikes me now, is also like a mirror. But a cloudy one, as if the flux of human thought condenses when one tries to put it into words.

I wasn't the only one to suffer. Hundreds died in the Zomba mudslide of 1931, but I count it as the moment when psychic night-and the physics of the atmosphere-entered my head. It has been a kind of dizziness in my life and oddly enough I was not the only one to feel it. For months after the mudslide there was an epidemic of dizziness-involving twitching tremors and falling down-among the local Chichewa. Some kind of psychosomatic response to the mudslide among those who survived, it spread like a contagion through the populace. It was often followed by nosebleeds. I had something like it, too, doctors said, and perhaps that is why the whole period is so hazy in my memory.

For all that, I miss Nyasaland greatly. It is part of what has formed me, and I would like to return there one day. I loved the rows of tobacco where they hung, lion-tawny, in the curing sheds. I loved the palm-fringed lake sh.o.r.e and those wicker baskets the weaver birds made their homes in, up the flashing ribbon of the Shire river-where, under towering gulfs of green, the boatmen pole their canoes to the rhythm of a soul-shuddering song.

What happened to the past? Why was it taken away from me? Who siphoned it off, like the mosquitoes settling on the boatmen's backs to suck their blood?

Eleven.

At the end of the week, as instructed, I presented myself at the Ryman house for Sunday lunch. The Prophet greeted me himself. My first impression was of a man in his early fifties with an intelligent if somewhat anxious face supporting a ma.s.s of unruly, starting-up grey hair. Under a prominent forehead and over a small, flattened nose he wore black spectacles covered at the bridge with sticking plaster, a black tie under a starched, round-cornered collar, and an oldfashioned grey suit. The creases of his trousers were extremely well defined. The toe-caps of his shoes shone like billiard b.a.l.l.s. This was unusual. In my experience, scientists tend not to look after their shoes.

My eyes travelled back up his body. He was tall, I realised, his forehead high and smooth, his mouth downturned. He did not seem like the jolliest soul. In fact, apart from the wild hair, Professor Ryman looked like an undertaker.

"I'm sorry I could not see you when you last called, Mr Meadows; I was gardening," he said. "A beautiful theory, without any mercy, has had me in its thrall and I find the garden the best way to escape. It is now finished. At least, I have written it down. Come through." His voice was an odd mixture of smooth and rough, beginning mellifluously and ending in a kind of cough, as if he were a singer who had found a crumb in his throat.

I followed him down the hall, under the strange array of strings and pipes on which I had previously banged my head and past a large pier mirror, improbably grand for that spartan household.

"May I ask what it was about, your theory?" I said, manoeuvring myself around a large stove which stood, oddly and inconveniently, at the foot of the stairs.

I received no reply.

We entered the drawing room, which was dominated by a grandfather clock and a piano. Mrs Ryman and a cleric in a dog-collar were conversing by the window. "That is the gnostic position," I heard the minister say. "An unfolding. The disclosure of what appears to be secret."

Ryman paused for a moment. His shoulders hunched appreciably but he did not look round at me. "The latent roots of a matrix," he said abruptly, in answer to my question, which I had almost forgotten asking.

The minister, a florid gentleman, was continuing his own discourse. "So that what's inside is equivalent to what is outside. But the equivalence itself is the secret. In the Orphic rite, you know, the mystic was he who kept his mouth shut. The mute. Muein Muein in the original Greek, giving rise to in the original Greek, giving rise to mustes mustes, mystic. Do you see?"

Mrs Ryman nodded. I stared at her, startled by the feelings which were rising in me. The skin on her face was so luxuriantly healthy I had a curious desire to lick it. I tried to put this bizarre idea out of my head, but my attention then became fixed on her generous body as she listened to the clergyman. She wore a green cardigan and tweed skirt and a white blouse with something gold pinned over the left breast. It was too homely a look to be alluring, I told myself, but this was more than compensated for by her youth. She was, it struck me, about twenty years younger than her husband. Such disparities of age were more common then than now, but I still wondered, at the time, how they could have come together.

"I am afraid I cannot offer you sherry," said Ryman. "We're abstainers here. Some apple juice, perhaps?"

I accepted and smiled at Mrs Ryman as she brought over her guest to meet me. The minister was dressed in black, apart from his dog-collar.

"Minister Grant," she said. "This is Henry Meadows. Our young man in the field. He is working for the Meteorological Office."

"Literally in the field," I said, shaking his hand. "We've established a small weather observation centre in the field next door."

"How lucky you are," said Grant. "To be under the very gaze of a t.i.tan of your science." He had a red face and rheumy eyes. I suspect he missed the sherry even more than I did.

To break the ice, I thought it might be amusing to tell them all about Pyke, Brecher and the sea lion.

"Ingenious," said Grant, when I had finished. "Train up a seal."

"Sea lion," said Ryman frostily. I was getting the distinct impression he did not like Grant. "Surely they do not plan to use these animals on attack missions?" he asked me. "Men may be stupid enough and callous enough to kill one another, but there is no need to involve innocent animals as well."

"I don't believe attack is part of the plan," I said. "The idea is for them to detect mines. Mr Pyke said they can see in very low light, diving down as far as six hundred and fifty feet. The potential is incredible."

"The word 'potential' should be used only in its strictest scientific sense," said Ryman. He paused, looking rather pleased with himself. "In all other cases it is misleading."

Perhaps he was right. In any case, I did not want to cause any more friction. "I believe you would quite like Mr Pyke, Professor," I said. "He's rather clever. He said he was at Cambridge with you."

Ryman looked sceptical, but I persevered. "And Julius Brecher, who has made some fascinating discoveries about the structure of the blood. He has unpicked haemoglobin. It is very important medically, I understand."

I was mainly parroting what Brecher had told me on the way to the pub. I was talking out of my depth-quite a bit out of my depth, actually-but Sir Peter had said a certain degree of cunning was necessary in this work. If deception must be employed, the higher morality of war work should cancel out the fault.

The stratagem worked. "Tell me more," said Ryman, suddenly filled with interest.

"Each red blood cell contains approximately six hundred and forty million haemoglobin molecules. Haem is iron in the ferrous state, as I am sure you know. Brecher found that a tetramer of globin chains join together with its own haem group in a pocket."

"Fascinating," said Ryman, his usually lugubrious face animated and full of light. "Do continue."

"The job of a haemoglobin molecule is to load and unload oxygen as it travels through the body. Its total journey, during a lifetime of one hundred and twenty days, is said to be three hundred miles."

"Did he say anything about the rhesus factor?" asked Mrs Ryman, to my surprise. For some reason I did not expect her to be so scientific as her husband. My mind flicked back to something Brecher had said about incompatibility of blood types between mother and baby.

"Gill," Ryman said in a soft but admonitory tone. She looked meekly into her gla.s.s of apple juice.

"Yes," I said, warily. "He did mention something of that."

There was a brief silence. Then, firm again, Mrs Ryman said, "Where is Brecher based?"

"He's at Loch Eck at the moment," I replied, "with Pyke; they stay at the Argyll-but his main work is at Cambridge."

I waited for either of them to elaborate, but once again there was silence. Grant, who had become distracted during the discussion, was inspecting the bra.s.s workings of the grandfather clock; I hung expectantly on an explanation of the reprimand.

Hung on so long, in fact, that even Ryman, who was clearly largely impervious to social convention, was driven to reply. "We recently gave blood to the transfusion service," he eventually said in an airy tone. "Shall we go through to eat?"

Mrs Ryman sat opposite me, with Grant and her husband at either end of the table, which was almost as highly polished as Ryman's shoes.

At once, Grant started banging on about mysticism and religion again. The substance of his views, though spoken at a volume suitable for general address, continued to be directed at Mrs Ryman. She was more concerned with ladling soup into our bowls out of a deep white porcelain tureen, but Grant didn't seem to notice his listener's lack of attention.

I took my opportunity. "What strikes me most, Professor, about your work-is the distance-to-neighbour aspect of things. It seems to me that measuring the relative distance between particles rather than measuring them from a fixed point will be an increasingly important tool."

Ryman beamed, apparently now glad to oblige me. "Yes, and not just with particles. The relationships between social groups, sets of ideas, even words themselves might be measured this way."

"Ideas?"

"Yes. I have often thought ideas pa.s.s through society in something of the manner of an ocean eddy. And like most things they are best considered differentially rather than as absolutes."

"By ideas you mean...?"

"Equality, liberty, justice. That sort of thing."

"That sort of thing," said the minister, looking up from his discussion with Mrs Ryman, "is dispensed in heaven."

Ryman ignored him. "We think we know what these ideas mean but actually they are like clouds in our heads. The best way to understand them is to cla.s.sify them by charting the distance between them."

"Scripture says love pa.s.seth all understanding," came the view from the other end of the table.

As the two men bickered, I became aware of Mrs Ryman's brown, enquiring eyes studying me across the table. Her face was glowing. It was a frank look she gave me but there was no tenderness in it, or anything remotely erotic. It was the look of someone inspecting produce at a market stall.

"Delicious soup," I said, leaning forward in my seat.

"From the garden." She lifted up the ladle. "Have some more."

"I'll save myself, thank you."

She gave a sly, sidelong glance at Grant. It was as if I was meant to see this.

"Handy during wartime," I said, "to grow your own veg."

"We were growing our own vegetables long before the war."

Grant snorted at a remark of Ryman's. "Have you not read your Isaiah? "My ways are above your ways, my thoughts above your thoughts." Our Lord is beyond even the very idea of the absolute. We judge by human standards, but it is only within the perfection of his law that we can understand the reason for evil. Till kingdom come and we join in that perfection, there's a limit we cannot cross. Thus, we cannot understand an abnormal phenomenon like Hitler."

"The present war is not about evil," said Ryman, in the tone of someone talking to a child. "It is about armaments."

"On the contrary, Professor. Hitler is evil. Invading countries. Suborning the rule of law. Interrogating with torture. Killing thousands of civilians. I would call that evil. I would say he presents a danger that only faith can answer."

"Rubbish! Faith itself is the dangerous thing," said Ryman. He relaxed slightly in his chair, like a chess player sensing victory. "Especially Christian faith. Christians are worst of all for fighting. The figures speak for themselves. I have them all down in my Statistics of Deadly Quarrels Statistics of Deadly Quarrels. Through history, there have been fewer wars started by adherents of Islam than by adherents of Christianity."

Grant fell silent, as if stumped by this information.

"Tell me, Professor," I said, "why did you make the switch from meteorology to the study of war?"

He put his hands down on the table to deliver what seemed a well-rehea.r.s.ed reply. "In the midst of my Cambridge course on natural science I was hesitating whether to specialise on the physics or biology, when someone told me that Helmholtz"-Helmholtz was a German scientist-"had been a medical doctor before becoming a physicist. It occurred to me then that Helmholtz had eaten the meal of life in the wrong order. I decided I would like to spend the first half of my life under the strict discipline of physics and afterwards apply that training to researches in biological and social sciences."

"What sort of researches?" I interjected, perhaps too rapidly. I suppose I was hoping that he might let slip the secrets of applying the Ryman number by explaining why he'd left the work behind.

It was too negative a way to seek revelation. Ryman just smiled as he recalled his non-meteorological triumphs. "A range of issues. The submissiveness of nations. War and eugenics. The measurability of sensations of hue. Many other topics of that type. Also psychology...quant.i.tative estimates of sensory events and abstract relations. The application of measurement to continuums. Getting pain and pleasure, touch and smell, aggressiveness and tranquillity down to equations. Say you were to begin by tapping someone softly with a horsewhip on the thigh-how many times and how hard would you have to hit before it became painful?"

As I considered this odd idea, his wife brought through the main course, which was roast chicken. Grant began chattering to her again. I stared for a second at the yellow bird, which sat on a platter in a pool of gravy, before turning back to Ryman. "Do you regret not taking your meteorological studies further?"

"I continue to dabble. I recently worked out how to detect the distance of thunderstorms from the number of clicks their electromagnetism makes on a telephone line. Do you mind carving? It upsets me."

Taking the carving knife and fork from him, I also decided to take the bull by the horns, or grasp the nettle, or whatever figure of speech is appropriate for a stubborn meteorologist. I stood up, ostensibly to perform my job of dissection, but also to ask him the question outright.

"The thing I have been wondering about is-how can you apply the Ryman number to adjacent zones with different background means...how do you connect it all up?" I wonder now if this question was what gave the game away.

To my surprise, he stood up from the table himself and walked to the window. From the way his shoulders hunched he seemed to be suppressing a burp. Or even laughter. Then he said, with his back to me, "The personal attribution is embarra.s.sing. Others named it."

I did not feel this was a proper answer to my question, so said nothing, hoping he would continue. But Ryman did not speak, instead staring out into the garden, up into Mackellar's field beyond. As I continued to carve, laying successive slices of the feathery white meat on the side of the platter, Gill Ryman carried in steaming dishes of vegetables. She set them either side of Grant, who, on seeing the curls of steam that came out of holes in the lids, exclaimed-in the tone of one declaiming a biblical quotation-"The tails of two smoking firebrands!"

Coming back to the table as I pa.s.sed out the chicken-loaded plates, Ryman produced a fountain pen and notepad from his jacket pocket. He began sketching and jotting down figures. Standing up as I was, I could clearly see that the designs and numbers were of a meteorological nature. I was confused. I felt as if he were toying with me.