He gave a little shudder, then handed me the sketch he had made earlier. It was a rough reproduction of the scene we had just witnessed. "That squall-it could be up over the top of the country along the east coast and down into the Channel by Tuesday. A real storm."

"But the weather in the Channel is good at the moment." As it happened, I had seen some charts that very week.

"That makes no difference. Conditions can change very quickly, and this is something even meteorologists often forget. I forgot it myself in France while I was writing Weather Prediction by Numerical Process Weather Prediction by Numerical Process, which is why there's a big mistake in that book."

He paused for a moment and looked at me with searching grey eyes. "Now tell me, Meadows, why has the Met Office set up an observatory on my doorstep?"

I felt a surge of panic. "Do you know, the truth is, sir, I am not quite sure," I said with as much smoothness as I could muster. "One just goes where one is sent."

It was a thoroughly unsatisfactory answer. Anyone with the least meteorological knowledge could see that Mackellar's field was an inappropriate place for an observatory, however small. I wondered if he already suspected me. He must have done.

Ryman drained a gla.s.s of water which was on the table, then set it down heavily. "Come on, it's stopped raining." He stared out of the window for a second. "Let's go for a walk."

Fourteen.

There was a tennis court behind the house, as well as the large vegetable garden I'd seen earlier. Ryman obviously enjoyed growing vegetables, for he insisted on showing me not just each plot but several plants individually. He then invited me to admire a still he had made that used solar energy to evaporate seawater.

We walked on, up through the wet field towards the cot-house. He asked me if I had any crackers or lizards, two older types of observation balloon used by meteorologists. I said I had, in case the more modern balloons got caught up or something went wrong with the transmission. Ryman asked me to fetch one cracker and one lizard, in order to see what the wind was doing at successive levels: when one is studying air moving across the horizontal it is convenient to define a mean wind whose velocity varies only with height.

"For old times' sake." His voice was full of wistfulness, as if, despite protestations to the contrary, he actually regretted the days when his pa.s.sion was hard meteorology rather than the more nebulous if nonetheless n.o.ble science of peace.

He followed me into the cot-house and looked over the meteorological equipment, while I began inflating the balloons with some hydrogen I had made according to Gwen and Joan's recipe. I was embarra.s.sed by the general squalor of the place, the piled ashtrays and empty beer bottles, but Ryman was only interested in the equipment.

"You don't mind me looking?" he said. I shook my head. As he poked about, I continued filling the balloons. I didn't want to get it wrong. There had been enough embarra.s.sment for one day.

We carried the balloons outside. They only just fitted through the door. Waving them behind us like a couple of kids, we continued walking up the slope of the field, towards the beech trees. Beyond them, at the top of the ridge, the fir plantation loured over us, its black trunks like soldiers preparing to march down and attack the intervening line of beeches.

"I often do this walk," he said. "Gill calls it my beech tree walk."

There was a good wind blowing in our faces by the time we reached the line of beeches-which as I say effectively divided the field from the plantation.

"There's a little stream and bridge in the middle," Ryman said. He took me into a glade in the stand of trees, and sure enough a stream ran through them, bisected by an old wooden bridge. "Mackellar's father built it," said Ryman, as we stood on the giving planks. "I find it a good place to observe eddies."

We looked down into the running water, watching its elusive folds and detours round stones and mossy branches. A stickleback darted across. "Straight from G.o.d's hand," said the Prophet. "Come on."

Going back into the field-with some regret, for the glade in which the bridge stood seemed like a special place-I took in the view. The steel chute used to get the timber out went down the side of the field to the sh.o.r.e road; a hedgerow and the outflow of the stream bordered the other. Across the middle of the field was the dry-stone wall separating Mackellar's property from Ryman's. In one corner the black cattle had gathered: a convocation of horns. Beyond it all could be seen the b.u.mpy green hills of the Cowal, interspersed with fragmentary glimpses of loch. It was like being on an archipelago.

With his cracker streaming out behind him, Ryman said, in a modest mumble, "I invented these, you know."

He began to explain to me how he had developed the cracker, in which a small explosive charge, triggered by an altimeter, goes off to alert the observer that the balloon has reached a certain height.

It turned out he had also invented the lizard, a more basic version of the same instrument, in which the balloon's tail is encased in a chiffon tube. This girdle forces the balloon to expand vertically-until it presses against a physical trigger and the tail is released, again as a signal.

"Hence the name lizard, from the habit of some of these animals to drop their tails when attacked," said Ryman.

"Geckoes," I said. I remembered them vividly from Nyasaland, sprinting up the wall after insects.

"Yes," he replied. "I suppose we should have called them that."

We worked on in silence for a minute or two. The sun had come out, making the foresters' steel chute glint. I became aware of the sound of the wind sliding between the leaves of the beeches and-a different sound-over the gra.s.s of Mackellar's pasture. This also shone slightly, as if every blade of gra.s.s had been polished up by a diligent attendant.

"I miss all this," Ryman said, as we continued preparing the balloons. "But my life now is concerned with the relative frequency of wars and how to prevent them." He laughed. "That is my war effort. To encourage submissiveness. Like Mr Gandhi."

Gandhi was admirable, no doubt, but as a policy Ryman's so-called war effort sounded too weedy for any self-respecting male to sign up to. And rather self-satisfied. But obviously I couldn't say that to him. "You mean you want us to submit to Hitler?" I asked, instead.

"It's nothing personal. Hitler, Churchill, Roosevelt, Stalin. Actually all one system. We are all part of a single self-aggravating system."

"I'm afraid I must disagree."

He sighed. "So do most people."

"If it were not for our airmen, our bombers and fighters, the war effort generally, we should now be part of Hitler's Reich."

"The bombers and fighters are part of the problem. If Germany had not built up its Luftwaffe in the 1930s, which it did to counterbalance our own naval power, there would not have been a war. The weapons should not have been acc.u.mulated in the first place. For a similar reason, I have a safe in my study, in which I keep my most current ma.n.u.scripts to protect them from fire, but I leave the door unlocked, so if any burglars came they would not use explosives."

"They might still steal them," I said, my stomach churning as I remembered the dropped sh.e.l.l cases. "Anyway, suppose that by 1935 Britain had developed armaments on a ma.s.sive scale, as we have now. If we had built up our arms then, we would have been able to hold the Germans down and get our own way all over the world."

"A childish ambition. Because, don't you see, then the whole world would have allied itself against our superiority? This war just would not have happened if arms had not been a.s.sembled. It does not make any difference by whom the process is started."

Ryman was a great mathematician, but as we stood there under those yawing, whispering beeches, with weather balloons pulling in our hands, his pacifism struck me as hopelessly naive, if not downright irresponsible.

I tried not to lose patience. "If there had been no armaments, we would have gone to war with our bare fists."

He just laughed. "Listen to yourself. You sound like someone in a Kipling book."

Finding ourselves at an impa.s.se of argument, we stood unspeaking, face to face, both listening to the wind as it pa.s.sed through the trees, making them stretch out their melancholy limbs.

There was another sound-air moving over the rubber of the balloons. A whining rasp, and I could tell from his face that it had provoked thought in him as well as me.

It was Ryman who spoke first. "That, and it is to the point, my young friend, is the sound of friction. You know, general friction will do more against Hitler even than General Patton." He gave another little laugh at the joke. "Because along with turbulence, friction is one of the most important things in the universe. Perhaps they can be described as cousins, even brothers. Or actually the same person, appearing in different profile."

A lone magpie, flying away from the sun, landed on the gra.s.s in front of us. I remembered suddenly how my mother on seeing one-well, she did it with the piebald crows in Africa-would immediately cross her thumbs and call out: I cross the magpie, I cross the magpie, The magpie crosses me, The magpie crosses me, Bad luck to the magpie, Bad luck to the magpie, Good luck to me. Good luck to me.

"Friction!" exclaimed Ryman as the bird flew off. "You see, Meadows, nothing can start without something to push off from. But good comes even when there's no positive action. Blocking, delaying, braking...these things create value just as the mixing of turbulence does, enabling the birth of new systems and the death of old ones, the transfer of energy from one place and time to another."

"But friction is mostly a negative force, socially speaking. It reduces efficiency."

"Yes, but that negativity prevents bad plans as much as good ones. That is why Hitler will eventually fail. Look, shall we fly these things or not? You're not tight there."

He took a piece of paper from his pocket and folded it inside the chiffon sleeve on my lizard, which had worked its way loose.

"They never came loose on the original balloons," said Ryman. "Gill made the sleeves. We tested them in a wind tunnel on the Isle of Wight. Mr Blackford, her father, is chief engineer at the Saunders-Roe seaplane factory in Cowes. I worked there for a while with him, doing research on aeroplane wings. That was how I met Gill."

So that was it. We released the balloons. Up they went then, cracker and lizard, red against the tall dark shapes of the beeches. Despite the wind there were no fierce vortices, and the balloons rose steadily at about 500 feet a minute, following the angles of the wind as it came in different layers over the green rooftops of the fir plantation. I remember a feeling of exhilaration watching them ascend.

I could see that Ryman was similarly enraptured. Like master and pupil, we watched until at 800 feet there was a sharp explosion-a flash in the sky. At the same time, the tail of my lizard came loose, plummeting down. The igniter from the cracker left a puff of smoke in the air. This dispersed as it fell, floating over the trees like a gauze.

Ryman and I then had a technical conversation about the implications of averaging out the different horizontal winds to produce a mean and what was really entailed, philosophically, by cla.s.sing turbulence as a deviation from this already artificial measure. He said the nature of an eddy was difficult to define precisely because its ident.i.ty was involved with its context; and that despite the mean's artificiality, eddies could not be specified independently of it.

It soon became too dark to continue, so we agreed to go home. Ryman seemed pleased with the balloons and we parted on good terms. He invited me to visit again soon.

"Maybe we might do some work together?" I ventured, aware that I had not got very much out of him about the Ryman number.

He gave me something half between a nod and a negative shake of the head, as if he wanted to say no but was trying to be polite.

I thought I should try to insist. "It would be an honour for me if it were possible. Is there a chance?"

He looked at me mistrustfully. "Perhaps. But as I say, I have found I do my best work alone."

As he spoke, the heavens opened again. (What a curious saying that is! As if there were a vault above. Levers and a hinge, operated by a divine magnet...) I desperately wanted to get an undertaking from Ryman. But it was soon raining heavily. Without further ado we ran across the field for shelter in our respective houses.

As the rain battered the slate roof of the cot-house, I dried my hair and boiled the kettle for a cup of tea. Having drunk it, I lay on the bed, smoking, worrying about what I was going to do. I wondered whether I should write a letter to Sir Peter. He had already written to me asking how I was getting on. I needed to reply. The invasion was ahead. But what would I tell him? The truth was that I'd got nowhere.

My mind turned to the flimsy blue missives from my parents that used to arrive at my boarding school. The mathematical gift had showed itself relatively early, and I won a scholarship place at Douai, a Benedictine public school in Berkshire. It was a wrench leaving Nyasaland and I looked forward to my holidays like nothing else.

My early schooldays were plagued by bedwetting and sleepwalking. My fellow pupils use to tease me, imitating my sleepwalking during the day. I apparently walked completely erect, but head down, with my chin on my chest. Once, on the eve of a test of French verbs, I climbed out of bed and wandered downstairs in a trance and started banging about in the kitchen, opening cupboards and throwing aside the battered tin pans in which we were served rice pudding. On being discovered by a member of staff and asked what I was doing, I told them I was 'looking for je suis je suis.

I wasn't much good at French, but in sciences I was a bit of a phenomenon at school. I had less difficulty with German and Latin, and this was a good thing because in those days you had to pa.s.s a Latin examination to get into Cambridge, and many of the most important scientific papers of the time were in German.

Once the holidays finally came, along with other colonial children I would join a ship of the Union Castle line to Cape Town. I would then take the mail steamer up the coast to Dar es Salaam in Tanganyika, where my father would pick me up. It will be strange to see that place again.

The drive across to Nyasaland across a highland escarpment which marked the edge of the Rift Valley was always very exciting; though being somewhat long and arduous the journey was of great concern to my mother as she waited at home on the farm. With the image in my head of her greeting us, one time or another-wearing a dress printed with flowers as the mud-spattered Land Rover pulled up outside the verandah, Vickers jumping manically up beside-I fell asleep, secure once again in those happy times, before the event. Before the kizunguzungu kizunguzungu, which was the Swahili word for the spinning dizziness to come.

I don't know what the Chichewa word was. We spoke kitchen Swahili to the servants because that's what my father had picked up in Kenya. I ought to apologise for it now, and I will happily do so, but at the time such an apology would have been inconceivable.

That was just how it was in those days. Whites didn't give politics a second thought. I myself certainly had no conception, as a boy, that it might be better not to talk to Cecilia and Gideon and the others in a lingua franca lingua franca of command which was as foreign to them as to us. Everyone in the house spoke English well enough but, ridiculously, it was used only when pidgin Swahili failed either them or us. Now, looking back, remembering Cecilia's mothering of me and Gideon's fond scolding of Vickers, I wish I had learned Chichewa. Some boys did, but they lived on farms even further off the map than ours. of command which was as foreign to them as to us. Everyone in the house spoke English well enough but, ridiculously, it was used only when pidgin Swahili failed either them or us. Now, looking back, remembering Cecilia's mothering of me and Gideon's fond scolding of Vickers, I wish I had learned Chichewa. Some boys did, but they lived on farms even further off the map than ours.

We were all in the Great Rift, that long strip of African country which, mostly let down through faults and slips and sudden fallings away, stretches from the lower Zambezi in the south to Ethiopia in the north. Related rifts continue across the Red Sea into the Jordan Valley. But beginning with Lake Nyasa and bifurcating at its top end into Lakes Tanganyika, Kivu, Edward and Albert on the western side, and a vast series of mountainous gulfs and plunges up through towards Lake Rudolf and beyond in the east-my rift, the Great Rift, was formed when rigid bas.e.m.e.nt rocks buckled during the last continental shift, lowering and raising great blocks of land as if they were nursery bricks. In between these two arms sat Uganda and the vast basin of Lake Victoria, and volcanic extrusions such as the Ruwenzori.

Ugandans, Kenyans, Tanganyikans, Nyasalanders, the white settler on his farm, the Indian merchant selling soap and sugar at his duka duka -we were all turning in the lava that runs in the splits between cultures, all spinning and tumbling as we fell like sc.r.a.ps of paper into those running streams. Some individuals were burned in an instant. Many whole tribes were choked and scorched and incinerated. Some were bloodied by floating boulders. Others there were who were overwhelmed simply by the smoke of distant battle. -we were all turning in the lava that runs in the splits between cultures, all spinning and tumbling as we fell like sc.r.a.ps of paper into those running streams. Some individuals were burned in an instant. Many whole tribes were choked and scorched and incinerated. Some were bloodied by floating boulders. Others there were who were overwhelmed simply by the smoke of distant battle.

But of the white tribe we can say one thing with certainty. We were the most stupid. Some of us had no idea whatsoever it would ever end, no conception at all that at imperial sunset another formation might appear, rising like a sea monster out of the molten depths.

Out of the fault.

The Rift.

The Great Rift.

There is every cause to believe that there is more extraordinary geological activity to come in the Great Lakes region. A man named Bullard who had been a research student in Rutherford's laboratory, and was still at Cambridge when I turned up there, did some fascinating work on this subject. He showed that gravity is lower than it ought to be in some of these Rift lakes. This negative gravity means there is material down there that's lighter than its surroundings, material that's longing to rise-and would do so in an instant were it not for side-pressing rocks holding it down like a pair of pliers. Bullard's anomalies mean some of the Rift is not just foundered valleys, the consequence of a fall.

Some of it must have been pushed down. If there is a shift of plate tectonics, that material will come flying up.

Fifteen.

A week after my lunch with the Rymans I was working over some charts in the cot-house when there was a knock on the door. It was Gill. She was carrying a round wooden tray on which stood tall tumblers full of ice and a jug of straw-coloured liquid. She was dressed in a skirt and blouse: some kind of heavy, yellowish, iridescent silk for the skirt and another material, the colour of limestone, for the blouse. Her figure seemed fuller, somehow, as if it were a fold one might enter. I felt a shiver of desire. week after my lunch with the Rymans I was working over some charts in the cot-house when there was a knock on the door. It was Gill. She was carrying a round wooden tray on which stood tall tumblers full of ice and a jug of straw-coloured liquid. She was dressed in a skirt and blouse: some kind of heavy, yellowish, iridescent silk for the skirt and another material, the colour of limestone, for the blouse. Her figure seemed fuller, somehow, as if it were a fold one might enter. I felt a shiver of desire.

It made me nervous to see her. Although taking any opportunity to see Ryman himself, I'd been keeping a low profile so far as his wife was concerned, for obvious reasons.

"I thought you might like some lemonade," she said.

"Lemons? At this time of year? In Scotland?"

Her high heels ticked across the tiled floor. I had never seen her in anything but flat shoes before.

"We use lemon essence, actually. And citric acid. Wallace makes it." She came over and put the tray down on the desk where I was working, peering over my chart as she poured a gla.s.s. "What are you working on?"

"Some rather intricate upper-air conditions."

"Oh," she said. "That." She went to the bed and sat down, smoothing her skirt. "You know, Wallace once had a plan to chequer the globe with reporters who'd send in upper-air data to computers in his forecast factory, all calculating away."

In those days the word computer was used to refer to human beings with slide-rules. Effectively, back then, it meant mathematicians. It was another term she used which seemed strange to me at the time. "Forecast factory?" I queried.

"Yes, a large hall like a theatre in which all the computers, men as well as women, would sit doing their calculations, keeping pace with the weather as it was reported-by telegrams."

"That would mean a lot of telegrams."

"Or by radio. Or telephone, though that would be expensive. Every three hours each of the sixty-four thousand computers would receive a message from his or her area of the world."

"Sixty-four thousand people? In one room?"

"Yes, working in parallel as the weather moved across the globe."

I humoured her. "It would have to be an awfully big theatre. More like a football stadium."

"He has in mind something like the Albert Hall, overseen by a conductor."

She stood up and swept her hands across the room. "A map of the world is painted on the walls of the chamber: the Arctic on the ceiling, England in the gallery. In the upper circle, the tropics. Dress circle? Australia. Antarctic in the pit. Desk by desk, each computer attends to the mathematical quant.i.ties, broken down by type-pressure, temperature, humidity-for his or her region. Then works them through the appropriate equations. Do you see?"

"Sort of." I took a hesitant sip of the lemonade. I was right to be doubtful. It was frightfully bitter and chemical. "Each computer pa.s.ses the solution to his equation to his neighbour, and so on."

"Oh no, it's much better than that. On each desk is a visual display showing the values for that equation once it is worked out. These are read by one's neighbours and by a higher official who co-ordinates the work of each region and maintains communication throughout the system, reporting to the central conductor." She paused. "All the basic-level computers wear a uniform to encourage discipline-though I don't suppose Wallace would want it to be anything like a military one. Perhaps something like the police, with the higher officials displaying special chevrons to distinguish them from the ordinaries. No one speaks, it's all done by writing on slips."

It took me more than a few seconds to absorb all this. As I was doing so, with ever more animated gestures, Gill explained how the 'conductor' would co-ordinate information about the future weather as it flowed north and south, east and west, each flow mirrored by what was happening on the floor of the forecast factory.

It was a pretty bizarre scenario, effectively treating men as machines working in parallel, but it was the issue of representation that puzzled me most.