"What did Eisenhower say?" I asked.

"Nothing. He just said nothing. And according to General Bull, D-Day is still on for Monday." Stagg walked up to the little window of the hut and looked out into the night sky, which showed no signs of disturbance. "You know, I have almost given up hope that we will get it right. Some of those b.l.o.o.d.y generals simply look outside, see fine weather and say, go!"

"Look," I said, summoning up courage before that formidably tempestuous personality. "I really think you should let me have a look at those WANTAC instruments. They have arrived now."

"And what do you propose?" Stagg asked, gritting his teeth as if to prevent angry words from flying between them.

"There is a wind tunnel and the other necessary equipment at the Saunders-Roe factory across in Cowes. I could be there and back in a day, taking the gauges with me. I will do some tests and the results will tell us whether WANTAC's readings have been mistakes or genuine. We will know whether it was a case of the instruments or the weather."

It seemed like an age before he replied. I remember he appeared to shiver as he sat there in that hut on the bluff, as if trembling under the weight of the responsibility that had been placed upon him.

"Very well, Henry. One day only, mind."

Three.

The wind tunnel at Saunders-Roe was octagonal in cross-section and about forty feet long. Constructed in perspex, so that experiments could be viewed from outside, it had a use-able floor area twelve feet across and there was a door at each end. Wind was blown down the tunnel by a heavy-duty electric fan. Turbulence was produced by its three vanes, shaped to act as aerofoils, the angle of which could be adjusted to produce the required frequency and amplitude of perturbation.

Earlier that morning, grateful there were not many people about because it was a Sat.u.r.day, I had already tested the barometers in a pressure chamber on the site. They worked perfectly. Now it was a question of letting winds of different speeds run past the anemometers I had set up in the tunnel, to see how they performed.

I could see down the tunnel, the length of which was illuminated by incandescent lamps flaring overhead. I switched on the fan and, with a roar, the blast began. It was jolly hard work, writing down the measurements on each dial-the wind kept flipping up my notepad-but very quickly I came to the conclusion that the WANTAC anemometers, too, could be trusted.

If it wasn't a question of instrument error, then it could only be the weather itself that was responsible for the anomalous readings. I was so excited that, with the man-made wind still roaring about me, I paced up and down behind the installations like a boy on the beach pointing out ships in a storm, trying to calculate what this meant for Monday's invasion. The coming weather suggested by WANTAC was still not yet calm enough to make landings possible; but it looked as if more favourable conditions were coming, and soon.

The question was still when? when? Working out how long it would take for the calmer weather to reach the Channel would involve a.n.a.lysis of the range of values of the Ryman number, but there was very little time to do the calculations. How could I possibly do all that maths in one day? It seemed impossible as a solo effort. Working out how long it would take for the calmer weather to reach the Channel would involve a.n.a.lysis of the range of values of the Ryman number, but there was very little time to do the calculations. How could I possibly do all that maths in one day? It seemed impossible as a solo effort.

As I was deliberating whether it might be feasible, the door at the other end of the tunnel opened and somebody walked in. At first I thought it was the tunnel supervisor at Saunders-Roe, who had greeted me when I first arrived-there had been no sign of Mr Blackford-but it was a woman carrying a small brown-leather suitcase.

She wore a woollen black coat and a long knitted red scarf tied loosely round her neck, streaming out behind her like a windsock in the onrushing gale. The coat was open, revealing a blouse with a high white collar, a V-neck jumper, and a skirt reaching almost to the floor. The suitcase was swinging like a pendulum.

I dumbly recognised Gill Ryman. She walked towards me quickly, knocking from side to side, blown off balance by the blast roaring by, her clothes flapping around her.

She looked older, and the clothing pressed hard against her body by the wind confirmed clearly that she was no longer pregnant. Her hair streamed out behind, parallel with the scarf. Behind its knitted length, ta.s.sels fluttered in turn, each one trembling its own little wake.

Immobile for a second, I felt as if my confused feelings for her, so long shut away in darkness and sighing, were about to be released; as if a squeezing hand was being released and something springing forth.

"Gill!" I cried, eventually rushing forward to embrace her. She felt extremely thin. She stood there awkwardly for a few seconds, inert in my arms with the wind tearing at us down the tunnel, plucking at our clothes and hair.

Time seemed to stand still, and then she freed herself from me-pushing me away with the little brown case. I heard myself begin to speak, "I'm so sorry...I wrote, just yesterday, but I expect you haven't-"

"I can't hear you!" Shouting into the wind's roar, she staggered, almost falling down. I clasped her again.

As she spoke, we wheeled about in the rush and she had to hold on to me. I was aware of a blurring of boundaries. It was as if, in that moment, her spirit and mine were cl.u.s.tering together under the influence of something larger-something fundamental in which we were both intimately involved, like molecules moving in the same direction, following the flow of the medium in which they were carried.

"I'll turn it off," I shouted back.

I walked to the control panel and reached down for the switch. With an unearthly moan, the fan slowed. The gale ceased. Suddenly, all was quiet.

As I came back towards her, Gill put down the suitcase. She came close, studying me hard, both of us still blinking from the effect of wind. "I wrote," I said, eventually. "Not the right words I expect, but...well, I am sorry."

She covered her ears with her hands. "Do stop all that, please." She was frowning as she did this, and s.c.r.e.w.i.n.g up her eyes.

"You destroyed me by destroying him," she continued eventually, letting her hands fall and reopening her eyes, "but I have not come here to hear you apologise. You already did that in your letter. And besides, I owe you an apology myself, for that business with the blood and...Embarra.s.sing-I was not myself."

"Of course not."

"It only came yesterday." She had taken my letter out of her pocket. "My father did not want me to come here today. He refused to bring me. I had to drive myself. He was very fond of Wallace. He holds you entirely to blame for his death."

I felt nausea in my stomach and a rising whirling in my head. "And for your baby's, I gather. I'm so sorry, Gill-if I had thought..."

She shook her head. "That was not your fault, though obviously Wallace's death did not help. But I have miscarried on many occasions previously. The rhesus factor-which is why I sat up when I heard you talk about Brecher at lunch that day. This was my eighth, so I am quite used to it by now. But each did seem to happen earlier than the last, which is why I left Kilmun when I did." She spoke coldly, as if not about herself or her body.

"I'm so sorry, Gill, all the same. About the child as well as Wallace."

"For G.o.d's sake!" She stepped towards me, lifting a hand as if to strike me, then reached out for my face, squeezing it hard and painfully between her fingers and thumb. Her face was inches from mine. "Shut up. Just shut up." Then she pushed away from me, shaking her head and falling to her knees on the floor of the wind tunnel, sobbing.

I knelt down beside her, patting her shoulder ineffectually, almost overcome by fugue-like dizziness.

She took out a handkerchief and dabbed her eyes, then got to her feet. "It's all right, it's all right. I'm sorry. G.o.d sees all things; he shall not despise a contrite heart. That is what I keep reminding myself when I think about you, Henry."

Despite my relief that she seemed to have recovered from the desire to mete violence on me, I recoiled from these devout sentiments. "G.o.d!" I cried. "I wish I knew him. If I had then I might not have had such cursed luck. I am afraid I have become like Wallace. I don't believe in G.o.d any more, after what happened."

"Wallace actually saw G.o.d in everything," she said, affronted. "It's just that people didn't realise."

The steel door at the far end of the tunnel banged open. Now it was indeed the supervisor from Saunders-Roe coming in. "Everything all right in here?" he called out doubtfully.

"Yes, fine, thank you," I replied. "I think I'll pack up now. I've got what I came for."

"What were you testing?" Gill asked, looking down the tunnel at the anemometers as the supervisor left.

"Wind speeds on ships. We've been getting errant readings. Well, they seemed errant, but actually I think they are correct. I have now got to work out your husband's number for adjacent areas of the North Atlantic and the Channel. I don't think I've got enough time. I'm afraid I must rush back for the boat to Portsmouth. Gill-I'm working on...well, it's the war."

"Of course," she said. "I understand. I can drive you to the pier, if that is any help. You'll make the seven o'clock."

"That would be wonderful."

She dug in a pocket to check for car keys, then picked up the suitcase and began walking to the door of the tunnel. I gathered up my equipment, stowed it in a large kitbag, and then joined her.

"So, you live here now?" I asked awkwardly as we walked into dusky light outside the wind tunnel. One of the workers from the factory was painting the number 52 on a large flying boat mounted on trestles.

"Yes," she replied. "But in Seaview, not Cowes. I couldn't face going back to Scotland, not after losing another baby. I had all our belongings sent down."

"We could meet again," I said. "Talk things over..."

She shook her head. "Look, do you want a lift or not?"

"Yes, of course. Thank you." We began walking towards the vehicle. "It seems like fate," I continued, "you coming here like this."

She looked at me, swinging the suitcase a little menacingly. "Fate? Wallace hated that word."

"But he thought everything was determined."

"Not exactly." We got into the car, a little blue Morris with red seats. I slung my kitbag into the back and she pa.s.sed the suitcase over the steering wheel to me, so it rested squarely on my lap.

"You mean he thought everything was determined, but not exactly?"

She frowned. "I mean he didn't think about it like that, in a religious way. He once said fate depended on the unpredictable relationship of different physical scales."

She put the key in the ignition. "You know what else he once said to me?"

"What?"

"That if anyone wanted to apply his number across a large s.p.a.ce, the thing to do was to take the weather readings in the centre of each adjacent quadrant of the atmosphere, not do the whole thing."

"I'm not sure that would work," I said. "There would be too many distortion errors in the rest of the quadrant."

"But worth a try, when you are in a bind, if you could simulate quasi-random turbulence of the outside parts?"

"Yes, I suppose..."

I suddenly felt extremely weary. I was unable to expel from my head the vision of Allied soldiers being dragged by the rip tide, mouths agape as, raked by machine-gun fire from the sh.o.r.e, they were tipped out of their landing craft into the waves. A tide of men, turning the wavetops red.

Gill carried on speaking in neutral, emotionless tones. "Well, I have brought something that might help. When we were in Scotland, and you you came, and Wallace told me of his suspicions of you, part of me wanted him to help you. I was always a bit frustrated that he had gone to ground in Kilmun not fully recognised for his achievements. Now that he is dead, I want him to have a legacy. And that is what I have brought you. At least, I hope so. Open the suitcase, Henry." came, and Wallace told me of his suspicions of you, part of me wanted him to help you. I was always a bit frustrated that he had gone to ground in Kilmun not fully recognised for his achievements. Now that he is dead, I want him to have a legacy. And that is what I have brought you. At least, I hope so. Open the suitcase, Henry."

Perplexed, I clicked the bra.s.s clasps and lifted the lid. Inside, to my great surprise, laid out in the original green baize mould, were the eight sh.e.l.l cases I had last seen in Ryman's study. I looked across at Gill for an explanation. I had a peculiar sensation of impending judgement, as if I were about to go before the beak.

She smiled unnervingly, as if pleased to see me foxed. "Wallace used these to simulate the action of turbulence round the central calculation in each quadrant. That is how he got round the problem of crossing from one weather system to the next."

"But how?" I said, taking the largest sh.e.l.l case out of the mould. Even as I did so, I began to have an inkling of the answer, for inside the sh.e.l.l case I felt weight shift; there was also a sandy, tinkling noise, like that heard in a kaleidoscope, or a box of seeds.

"Give it to me," commanded Gill. "And cup your hands." Again I had the feeling of going before the law.

I did as she said, and she began uns.c.r.e.w.i.n.g the end of the sh.e.l.l. With very careful movements she tipped out some of its contents into the receptacle of my joined palms. What spilled out were tiny bra.s.s digits, pressed out of sheet metal. Inside the sh.e.l.l were hundreds more.

"He had them precision-made in Germany, and collected them from there after his trip to Poland in 1939. That was partly why he went to Berlin."

Suddenly, as if in a flash of revealed knowledge, I began to see the shape of the method, but Gill was a long way ahead of me. "It's very important you don't lose any," she explained, touching the mound of numbers in my hands with a finger. "Each sh.e.l.l case contains a different amount of digits, so within a certain range you can choose the minimum and maximum values for each set of numbers you want. Wallace used to shake the sh.e.l.l case like a maraca, pour out a pile of these on a table, then close his eyes to pick out an amount of digits determined by the nature of the underlying calculation."

I was amazed she had such a grasp of it all. "Those digits effectively become the seed for further calculations," she continued, speaking in the same authoritative tone.

"Worked out mathematically?" I asked, looking at the pile of numbers still cupped in my palm.

She nodded. "Right. Put those back carefully. We have to get you to the ferry."

When we got to the pier, she would not allow me to kiss her, simply turning away with a melancholy smile and heading back to the Morris. Still hopeful of possibility even then, I watched her drive away.

I spent the journey across the Solent in a whirl of emotion mixed with mathematical thought. It was as if, finally, two parts of my brain had come together...Full of regret and sadness, and excitement and relief, carrying Gill's suitcase in my hand and the kitbag of instruments over my shoulder, I arrived back at Southwick just in time for the Sat.u.r.day night conference.

The weather outside the hut was still good, and the wartime measure of setting British Summer Time two hours ahead of GMT meant that there was still plenty of light, even at 9 PM PM. To a layman it would have looked all fine and dandy to launch an invasion on Monday-but the charts confirmed yesterday's view of coming storms.

I heard from one of the navy forecasters that Stagg had become indisposed-I imagined him vomiting again-during the 6 PM PM conference while I was away. Yates had had to take over as controller. conference while I was away. Yates had had to take over as controller.

But Stagg was back in his seat now. Things did not look good for Monday. The Admiralty's pessimism had worsened to meet Dunstable's. They also described another significant new storm which had formed in the US, to the east of the Great Lakes, which was moving towards the Atlantic and would soon come to dominate. Petterssen's upper-air work supported the rapid arrival of this 'Storm E', as we termed it.

Krick, as if beginning to accept the situation, made no mention of the 'finger of high pressure' he had maintained would insulate the Channel from the earlier oncoming Irish cold front. But he still thought it was OK to go. Out of solidarity, not conviction, he was persuaded by Stagg and Yates to allow a unanimous 'no'.

The WANTAC figures were still out of kilter, new instruments notwithstanding, which I took as further confirmation that the earlier readings were accurate.

After the conference I told Stagg what I'd discovered at Saunders-Roe. "We can trust WANTAC, in my view. But I don't know what it means yet. I have a suspicion that a ridge of high pressure might be developing there. More like a little tube than a ridge, maybe, but something. I tried to work it out on the ferry, but I need more time."

Ignoring the technical details of what I said relating to WANTAC, he gave me a sour look. "Time is exactly what we don't have." There was no point in telling him about Gill and the sh.e.l.l cases yet.

Keeping my counsel, I then accompanied Stagg and Yates to the door of the supreme commander's meeting down in the main house. As they were about to enter, Admiral Creasy bowled up the corridor. "h.e.l.lo, chaps. Some rea.s.suring news for us tonight? You look happier than when you went out yesterday, I must say."

Stagg gave him a forbearing smile. "I'm afraid I don't feel very much happier, sir."

"Well, we'll soon know the worst," said Creasy in reply, and they entered the meeting room. I waited outside with the other aides, but I knew what Stagg would tell the a.s.sembled bigwigs. That the weather over the British Isles in the next few days would be subject to complex patterns of turbulence, with force 5 winds in the Channel, much low cloud and risk of fog in sea areas. In fact, a series of three depressions were strung across the Atlantic and the result would be rough seas-far too rough for landing on Monday-and too much cloud for successful bombing operations or landing troops from air.

After the meeting, at about 11 PM PM, Stagg told me what had happened. Eisenhower had asked if there was a chance the forecast might be more optimistic tomorrow and Stagg had explained that the whole weather situation was extremely finely balanced. Last night, he had thought that there might be the slightest tip to the favourable side, but now it had gone too far to the other side for it to swing back again. Leigh Mallory, speaking for the RAF, had enquired what the conditions would be like for heavy bombers, then Eisenhower had again asked if Stagg felt he might be a bit more positive tomorrow (Sunday).

"I'm afraid not, sir," was all Stagg could say-adding to me, outside afterwards, "I've a feeling they are going to postpone. I get the sense Monty wants to go whatever, but Eisenhower is listening to us."

"But putting the ships back into harbour will cause mayhem."

"Yes," Stagg said dourly.

"And the Germans are bound to get wind of it."

"Yes," he said again, more dourly still.

As he recounted all this to me, Stagg and I were making a circuit in the moonlight round the forbidding Victorian mansion that was Southwick. Staff cars-Packards, Morrises, Lea Francises-were drawing up constantly, their tyres crunching on the gravel. Out of one of the cars, looking like Laurel and Hardy, s.m.u.ts and Churchill emerged-their faces, flashing in the porch light, were heavy with gloom. We turned away quickly, making another tour of the building, lest the PM should identify the weathermen bringing all the bad news.

"They say Eisenhower complains because Churchill eats all the doughnuts," whispered Stagg. "And Monty gets cross because Eisenhower smokes."

Stagg was relieved that he had at last been able to provide them all with an unqualified forecast, even though it probably meant the invasion was off. "I do feel a bit happier," he said, "but if there is good weather on Monday I'll hang for it."

We walked round the house, then towards a lawn at the front. The moon was full, there was almost no wind, the night sky was empty of clouds. Overall, it was almost like one of Ryman's brief moments of paradise-that condition of 'just no turbulence' which is as near to equilibrium as the atmosphere ever comes. Meanwhile we were forecasting thick cloud and strong wind in the Channel by morning. It didn't seem to stack up. But these background conditions of apparent calm were, in fact, exactly those times during which powerful events fermented. Besides, it was time I crossed my Rubicon.

"I'm going to go back and have one last go at applying the Ryman number in respect of WANTAC," I said as we looked out over the blackened grounds beyond the lawn we were approaching, where spectral lines of tents ploughed the gra.s.s and rhododendron bushes rose like sea monsters.

"Just explain again, can you, to a chump like me, why WANTAC is so singularly important and how it ties up with Ryman?"

"I think the reason WANTAC's showing different readings is that it is in the midst of one of Ryman's thin weather boundaries, at the edge of a small area of high pressure which would give us exactly the interval we need. I am satisfied the equipment is working properly, but I still haven't managed to make the figures stack up in a synoptic model. His number again."