The Girl Who Fell From the Sky

by Simon Mawer

  And suddenly she saw it. ‘Half a mile apart! No, twice that. They should be a mile apart!’ She almost laughed. She saw into his world for the first time: the pure outrage of having two nuclei so close together was something shocking, against nature.

  He nodded, as though it was obvious. ‘They should be a mile apart and instead they are touching. So they fly apart at colossal speeds to take up their correct distances. We don’t know exactly how fast they move. Maybe a tenth of the speed of light. The energy involved is vast. We talk of electron volts. Each uranium atom that splits apart like this releases two hundred million electron volts of energy. That’s …’ He seemed to scratch around for a way of saying it. ‘Oh, tiny, useless, enough to move a grain of sand. You can’t do anything with it, not in practical terms. But each kilogram of uranium contains a vast number of atoms – imagine twenty-five with twenty-three zeros after it, that’s the number. If all the atoms split one after another in this chain reaction, you have to multiply the amount of energy released from each nucleus by the total number of atoms. Suddenly you’ve got an immense amount of energy. Do you see what I mean? Potentially unlimited.’

  She thought of Clément trying to explain his work to her. It’s exactly like Kriegspiel, he had said: groping in the unseen with incomplete information and trying to find out what’s possible. And what was possible was some kind of bomb. She remembered the very last time they’d been together, at Easter time in Paris with her father and Ned, shortly after her seventeenth birthday. They’d walked close together. Occasionally their hands had touched. You mustn’t be frightened, he’d said to her.

  ‘You’re not listening, are you?’ Ned was saying. ‘You’re not paying attention.’

  ‘Yes, I am.’

  ‘If you want to understand, you’ve got to listen.’

  ‘I am listening.’

  ‘The point is, you must have a sufficiently large mass of uranium. That’s crucial. Remember what I’ve told you before: atoms are mainly nothing at all. The nuclei are like dust motes in an empty room, hard to hit and far apart. Neutrons can go a long way before encountering one, so if you haven’t got enough mass the neutrons simply escape into the air before they actually hit other atoms. Francis Perrin, another man in Joliot’s team, made an estimate of how much uranium you’d need to guarantee that the chain reaction happens. He called it la masse critique. He calculated forty-four tons. Or, with a casing that could reflect escaping neutrons back into the mass, a mere thirteen. He published that in the Comptes Rendus so it was completely open to the public. All that I’ve told you was published before the war for anyone to read and work it out for themselves. However, a short while later Joliot’s group filed a secret patent with the Caisse Nationale de la Recherche Scientifique entitled Perfectionnements des charges explosives. It’s a patent on how to make an atomic bomb.’

  It was a beautiful day. It should have been cold and miserable, threatening a storm. But instead the sun was shining, and leaves were glistening in the light.

  ‘And all this work was done in Paris?’

  ‘All in Paris. At the Collège de France, and at their other lab at Ivry. You came to the Collège once with Papa, don’t you remember?’

  ‘Of course I do. We took you and Clément out for lunch.’

  ‘It wasn’t the happiest of meals.’

  ‘You got angry over the slightest thing.’

  ‘I got angry over the way Clément pandered to you.’

  She hadn’t understood at the time, but now she did: the intricate complex of Ned’s jealousies. After lunch they’d walked along the quai where artists were selling paintings of the usual scenes: the cathedral directly across the river and the Eiffel Tower and nostalgic views of the alleyways of Montmartre. Clément had strolled along beside her, while Ned was condemned to walk ahead with their father. ‘Hurry up,’ he’d complained, looking back at them. ‘We must get back to the lab.’

  Clément had ignored him, leaning close to share his thoughts with her, laughing with her, teasing her. ‘I want to pull your leg,’ he said, using the English expression, which seemed to delight him but sounded outrageous to her, so outrageous that it had made her blush.

  ‘And what part did Clément play in all this?’

  ‘He worked on the critical mass problem. Natural uranium is made of two different kinds, different isotopes. Most of it, more than ninety-nine per cent, is uranium 238. A mere 0.3 per cent of natural uranium is the other kind. It’s called uranium 235. Clément worked on the calculations Perrin had used. Mean free paths and cross-sections and probabilities, a whole lot of stuff. Thermal neutrons and slow neutrons. And then he made a crucial observation: if it was only the uranium 235 that was responsible for the fission and if you could obtain a relatively pure sample of 235 then the calculations would be different. A forty-ton, even a twelve-ton atomic bomb is a lot of bomb. An aircraft couldn’t deliver it. But if you can increase the proportion of uranium 235 in your sample, then the value for the critical mass comes down dramatically.’

  ‘How dramatically?’

  ‘It depends on the degree of enrichment, and even then the maths is not certain. Clément’s revised calculations were in the order of pounds, not tons. Say ten, maybe even less. No mass at all.’ There was a rockery among the bushes at the centre of the garden. Ned went and picked up two large stones and brought them over. ‘Imagine these are lumps of uranium metal, each one a fraction below the critical mass.’ He handed them to her. ‘Imagine it’s uranium. It’s greyish and shiny. Quite decorative, really. Now smash the two together.’

  She did as she was told. A children’s game. Crash! And there was a faint and sulphurous smell of sparks.

  ‘There! That’s all there is to it. You’ve just blown London off the map and out of history. Vaporised.’

  ‘Merely by doing that everything vanishes?’

  ‘Merely by doing that. If the two lumps are below the critical mass, as long as you keep them separate nothing happens. Smash them together and the chain reaction begins, fast, almost as fast as the speed of light. The atoms break up in a cascade, each one causing the next two to split in turn and release their energy. If one kilogram of uranium went like that it would release the equivalent energy of twenty thousand tons of TNT, all detonated in a flash.’

  She knew TNT. She knew all the explosives: plastic, Nobel 808, ammonal, gun cotton. She knew how to shape a charge and how to fuse it and how to detonate it. She could break a railway line and put a train out of action, or a car. She might have a go at destroying a bridge, although you’d need to be an expert for that, like Benoît was. But not this, not a whole city, in an instant.

  ‘This is all theoretical, isn’t it?’

  ‘It’s as certain as existence itself.’

  She tossed the stones back among the bushes and brushed the soil from her hands. ‘I don’t believe you.’

  ‘That doesn’t make any difference. Whether you believe it or not doesn’t change the facts. It doesn’t depend on belief.’

  She looked around. There was the garden with the old plane trees, their camouflage trunks and shivering leaves; and beyond, the buildings of the square, one or two of them hollow shells, but still there; and the city itself, battered by the bombing but still incontrovertibly there. It was beyond imagining that it could all be blown away in an instant simply by banging two lumps of metal together.

  ‘And now they know all about me and Clément.’ It seemed unreal, circumstance and happenstance and pure coincidence coming together to create a small but terrifying explosion.

  She looked at him with an expression that tried to mollify her previous anger. ‘Do you remember playing Pig-in-the-middle, with me in the middle?’

  ‘We called it “collapsing the wave function”.’

  ‘It used to make me furious.’

  ‘But you kept playing, didn’t you? Because of Clément.’

  ‘That’s what I feel like now. The pig in the middle.’

  He smiled, a bitte
r little smile. ‘You always were,’ he said.

  ‘And I’ve got to keep playing?’

  ‘I’m afraid so.’

  XI

  The Cambridge train was full. All trains were full these days. Soldiers, airmen, men in dark suits carrying significant briefcases, academics in careless tweed jackets and ill-fitting grey flannels. IS YOUR JOURNEY REALLY NECESSARY? posters on every platform demanded, but half of England seemed to have reason enough.

  ‘Whose idea was this?’ she asked as the train trundled out through the London suburbs, ‘yours or theirs?’

  ‘Mine,’ he said.

  ‘Do they know about it?’

  He nodded. ‘They thought it a good idea. The personal touch. You’ll be more persuasive if you’ve met him.’

  ‘Who are they, Ned?’

  He smiled and shook his head, looking out through the window at the passing buildings. ‘You know I can’t tell you that.’

  Cambridge itself seemed smaller than Oxford, more delicate, more vulnerable, as though its only foundation, the fragile subsoil of learning, had been eroded by war and put the whole place in danger of dissolution. They took a bus from the station into the centre and walked a few minutes to where Free School Lane threaded its way between close, medieval buildings. Halfway along the lane there was a gothic gateway that might have belonged to a fourteenth-century monastery but actually announced itself as the Cavendish Laboratory. The porter had the manner of a household butler, at once obsequious and knowing. ‘You’ll be looking for Dr Kowarski, won’t you, sir? I think you’ll find him in his office.’

  ‘Thank you, Dawkins.’

  ‘Good to see you back, sir, if only for a brief visit.’

  ‘It’s good to be back, Dawkins. How are things going?’

  ‘Pretty strange, sir. Not many undergraduates these days, and an awful lot of hush-hush, if you get my meaning.’

  ‘I do, Dawkins, I do.’

  They climbed stairs and walked along corridors as cold and cheerless as a reform school. An open doorway gave a glimpse into a laboratory where a technician was fiddling with some elaborate piece of glassware. A poster explained the fire drill and where to assemble in the event of an evacuation. Windows were criss-crossed with adhesive tape. Finally Ned knocked at an anonymous door and a gruff voice called them in.

  The office they entered was as cluttered as a bear’s den. The window ledge was littered with the bones and sinews of electrical apparatus. On the desk was a scattering of files and open books. At the desk sat the bear himself. His hair was cut short, giving him the appearance of a Prussian army officer in one of Low’s cartoons but his manner was more the bluff heartiness of a Russian than a German. Yet he spoke French, that was the surprise – fluent French with a strong Slav accent. ‘Mon cher Edward! Je suis ravi de vous voir! And this lovely young lady is …?’

  ‘My sister Marian.’

  ‘Of course, of course. How charming.’ The bear took her hand and raised it to his lips. The gesture was curiously graceful, as though inside his great bulk there was a slender dandy trying to express himself.

  ‘This,’ Ned explained unnecessarily, ‘is Dr Lev Kowarski.’

  Kowarski cleared a chair for Marian to sit. ‘Ned has told me much about you. He promised me you were pretty, and instead I find that you are beautiful. That is the Englishman in him, mixing one with the other. A true Frenchman would never make such a grave mistake.’ He gave an expansive smile. ‘And neither would a Russian.’

  ‘I’m not sure how to answer that.’

  ‘There’s no need. Just accept the compliment. Ned tells me that you may soon meet up with a mutual friend of ours.’

  ‘Possibly.’ It seemed appalling. Her mission, her whole existence was meant to be secret yet here were people who knew all about it: the faceless Mr Fawley, the apologetic Colonel Peters, the Russian bear Kowarski, her own brother. How many others?

  ‘Well, you must tell him that I need him here. Forget Professor Chadwick’s invitation, forget the damned war effort – Lev Kowarski needs him!’

  ‘Will that be enough to persuade him?’

  The man grinned, looking at her sideways. ‘He’s a Frenchman. Put it to him this way: I need him because otherwise the whole project will be dominated by the Anglo-Saxons. Worse, by the Americans. France used to be in the lead in all this, and now she is being elbowed out of the way, so he is needed to help the French cause. Tell him …’ His eyes narrowed. ‘Tell him that they are running away with Fred’s work. Tell him that von Halban and Perrin have gone to Canada and left me here on my own. Tell him that I am nearly at the critical point – can you remember that? The critical point. Tell him …’ He glanced at Ned for a second. ‘Tell him that I am on the trail of element ninety-four. Remember that. Element ninety-four.’

  ‘That’s easy enough. But what does it mean?’

  Kowarski laughed again. It was a typical Russian laugh, humour on the surface but with a cold, dark current flowing underneath. ‘It means,’ he said, ‘the end of the war. Maybe the end of the world.’

  XII

  She waited beneath the clock at Paddington station, thinking about Alice. A young girl adrift in a sea of dreams, surrounded by monsters. It means the end of the war. Maybe the end of the world. It was a relief to see Benoît coming through the crowd carrying a kitbag and wearing Free French uniform. That’s what he had told her when they’d spoken on the phone: ‘I’ll wear my uniform. Maybe they’ll even mistake me for a gentleman.’ And she didn’t care whether he was a gentleman or not as they walked along the platform to the Oxford train – he was French, a lifeline to France, a real Frenchman against her dubious, hybrid Anglo-Frenchness. And a straightforward man against the anguished complexities of what Clément may or may not have been to her, or what he may or may not have been doing in the laboratories of the Collège de France.

  He flung open his arms and embraced her while the other passengers looked on with condescending smiles. Why was she up in London again? Was she seeing another man? Did she have lovers all over the country?

  She laughed at his absurd ideas, and wondered whether she would tell him what had happened. ‘I saw my brother. We went to Cambridge for the day. King’s College chapel. Punting on the Backs. All the tourist things.’

  He didn’t know the Backs. He didn’t know what a punt was. She tried to explain – une barque à fond plat – while people stared. Speaking the language in public made her feel different, as though a mere change of syntax and vocabulary could transform the reserved English girl into a vivacious Gallic: Marian into Marianne. They talked throughout the journey, volubly, carelessly, confident that the others in the compartment would never be able to follow their rapid flood of French. Did he have news of their departure?

  ‘Any time from next Wednesday, that’s what they said. Once the moon is into its first quarter. But the shitty English weather means that there’s a queue of people built up. It’s like the London rush hour in the rain, everyone waiting for taxis.’

  They took the bus from the station and reached the house in the Banbury Road in time for dinner. Her mother fell for him. He was tall and good-looking and, above all, French; and he seemed to understand exactly what manner of words would delight her. ‘Now I understand where Anne-Marie gets her beauty from,’ he told her when they were introduced.

  There was a fleeting puzzlement behind her grateful smile. ‘Anne-Marie?’

  Benoît reddened.

  ‘Marianne,’ Marian said. ‘He’s always fooling about with names. Sometimes he calls me Alice as well.’

  ‘From Wonderland,’ Benoît added, and even that seemed to be a Gallic compliment. Her mother smiled and the faux pas was forgotten, but as soon as they were alone together, he protested: ‘I am invited to stay at this girl’s house and she hasn’t even told me her name! You aren’t Anne-Marie? You are Marianne? You make me look a fool.’

  ‘I completely forgot to tell you. And I rather like Anne-Marie. It’s my cover name, you kno
w that. Anne-Marie Laroche.’

  ‘So what are you really called?’

  There was something thrilling about telling him a truth. ‘Marian,’ she said, ‘Marian Sutro.’

  ‘Sutro? What kind of name is that?’

  ‘It’s English. As you can see, my father’s very English.’

  ‘Seeming English doesn’t mean a thing. Half the bloody English seem English but aren’t. Look at Churchill. He’s half American. And look at your king. He’s mostly German, for God’s sake!’

  They went to the cinema that evening, sitting in the sweltering darkness of the back stalls with other couples all around them, heaving and grunting. The first feature was a Pathé News report that spoke of fleets of bombers thundering across the sky between Britain and northern Germany. Hamburg Hammered, it was called. Aircraft trailed long plumes of vapour across the sky, with American airmen aiming machine guns at unseen enemies. And then the city at night, a galaxy of flame. The RAF by night, the USAAF by day. Round the clock, the commentator said. He talked of seven square miles of the city laid waste, twelve thousand tons of bombs dropped, fifty-eight thousand dead, numbers impossible to comprehend. The audience stirred in their seats and emitted a sound, something atavistic, both horrified and gleeful at one and the same time.

  The main feature came as a relief, some concoction of intrigue and romance starring Joseph Cotten. As three and a half years of war had taught, she pushed the horror aside and felt sixteen again, awkward in the presence of a half-known youth beside her, wary of his motives and intentions, and her own. When he put his arm around her something stirred inside, an emotion that seemed akin to fear – the same pulse, the same sweat of panic – but when he turned her head and kissed her on the neck and then on the mouth, she turned away. ‘Please,’ she whispered. ‘Not now.’

  She sat there in the darkness with Benoît’s arm around her, wondering what she felt. And Clément, what she felt about Clément. She still had his letters, those that had been allowed to reach her. Scraps of paper that she held to herself and treasured and reread as though they were mysterious messages, with hidden meanings enciphered within the plain text. Je t’embrasse. The sense hovering between kiss and embrace and love. My uncle, she had told the nuns. Only my uncle. And as though they were written in some strange code, they never guessed what the words meant. But Fawley, the placid, thoughtful Fawley, had understood.