Experimenters, including Blackett in London, downed tools, changed their plans and began programmes of experiments to investigate Shankland’s claims. A few months later, however, it became clear that he had been wrong and that energy was indeed conserved. The false alarm made a deep impression on Dirac. A year later, he wrote ruefully to Blackett: ‘After Shankland, I feel very sceptical of all unexpected experimental results. I think one should wait a year or so to see that further experiments do not contradict the previous results, before getting worried about them.’32 Dirac’s inclination to believe exciting new observations had been irreversibly undermined.
After another secret Christmas vacation with Manci and her children in Austria and Hungary, marriage was now on the cards.33 But Dirac could not bring himself to commit. No one knew of his inner turmoil; all they saw was the familiar meditative Dirac, the prince of asceticism, going wordlessly about his business. But in private he was not quite as cold and detached as he seemed to be. On his mantelpiece, he kept a photograph of Manci in a swimsuit, but no one saw it: when there was a knock on the door of his college rooms, he took the photograph down and hid it in a drawer. When many of his associates thought he was working, he was sloping off to see Mickey Mouse films, taking the Kapitza boys out for runs in his new car and reading T. E. Lawrence’s Seven Pillars of Wisdom. In a bid to make Dirac more self-aware, Manci recommended that he read Aldous Huxley’s Point Counterpoint as she thought Dirac resembled the novel’s character Philip Quarles: brilliant, solitary, emotionally ‘a foreigner’ and entrenched ‘in that calm, remote, frigid silence’.34 Not seeing the likeness, he wrote to Manci: ‘I doubt whether I am really like Philip Quarles, because his parents are not really like mine,’ underlining – perhaps unconsciously – the importance of his mother and father to his sense of identity.
Dirac wrote his letters to Manci before he went to bed, ‘the best time for thinking about you’. He never mentioned his work, nor did she enquire about it, and he rarely referred to his colleagues, but he did make an exception in February, shortly before he was due to meet Bohr and his wife in London.35 It was not long before Manci tired of the praise Dirac heaped on his elderly friend in one letter after another; ‘Bohr, Bohr, Bohr,’ she yawned. Dirac was surprisingly sensitive to these complaints and showed that he appreciated that her hair-trigger jealousy needed to be handled with care by toning down the complimentary references to colleagues he admired.36 His tact was tested again shortly before the Easter vacation, when Manci was hoping to see him. He explained to her that he felt duty-bound to visit his parents, as he had not seen them for several months; the problem was that after his visit to Bristol he would be in no fit psychological state to meet her:
It really will change me very much when I go home; it will make me afraid to do anything for my own pleasure. I shall probably be afraid to think of you […] I find it satisfies me to be able to think of you whenever I wish. Why cannot you be satisfied in the same way? You should cultivate your imagination […] It would be no use for me to see you for one or two days because, as you know, I am never kind to you the first day or two when I meet you.37
Dirac pleaded with her to understand the paralysis that overcame him whenever he set foot in 6 Julius Road: ‘If you cannot understand this, you will never understand me.’38 But Manci showed no sympathy; he was selfish, she told him. She had no interest in cultivating her imagination – she was not asking the Earth; all she wanted was to see her man in the flesh:
You do not consider anything but from your point of view. We are very different in [that] you never think to help people or to make them happy in spite [of the fact] that you are in the lucky situation where it would be easy to do so … I like you less.39
She got her way. Shortly before Easter, Dirac returned to Bristol for a few days and, after taking a few days to recover, organised a vacation with Manci in Budapest. ‘I cannot imagine being happier than I was with you,’ she wrote to him. Finding it hard to express his joy, he assured her that the vacation left him ‘not wanting feminine society at all’.40
After Easter, Dirac’s colleagues in St John’s were surprised to see him so sunburnt, and when they asked him where he had been, he replied, ‘Yugoslavia.’41 The first casualty of Dirac’s secret love was his commitment to literal truth.42
During the first week of June 1936, Dirac was gathering together his rucksack, sleeping bag, ice axe, rope and crampons, preparing for his next climbing vacation in the USSR with Tamm.43 Besides visiting Kapitza, he wanted to be in the Caucasus on 19 June to see a solar eclipse, the first he will have seen. Before leaving, he wrote to Manci, asking her not to write to him because if Tamm and Kapitza ‘notice [that] you and I write very much to each other, then very quickly the news would spread to physicists all over the world and they would all gossip about us’.44
Kapitza was in better spirits, reading his subscription copies of the New Statesman and supervising the building of his new institute. Many of its rooms were replicas of ones in the Mond Laboratory, though Kapitza ensured that his new director’s office was even grander, with an even larger footprint. After he demanded that every item of his laboratory equipment should be transferred, Rutherford complained that it seemed Kapitza would not be happy until the paint of the Mond Laboratory had been scraped off the walls.45 The Soviet Union was still the talk of the Cambridge common rooms, and the Cambridge Review abounded with articles about it, including a sceptical review of Crowther’s Soviet Science, a whitewash that declared the Stalinist state’s interference in science to be minimal. The Trinity College scholar Anthony Blunt, later a distinguished art historian, wrote an article on how a gentleman traveller might make the most of Russian hospitality – the champagne and the caviar, if not the bed bugs.46 Unknown to his colleagues, Blunt had recently become a Soviet spy.
Shortly before Dirac set off for Russia, he heard from his mother that his father was severely ill with pleurisy: every breath was painful and liable to be accompanied by a stabbing pain in his midriff. Flo wrote that the family doctor had ordered her husband to stay in bed for ten days but assured her that ‘I’m not to worry as Pa is the kind of man to make the worse of anything just to keep me busy.’47 From the tone of his mother’s letter, Dirac sensed that his father was not seriously ill, and he knew his parents were supported by Betty, about to move permanently to London to become a secretary.48 So he decided to set off on vacation and arrived in Moscow on Saturday, but within hours received a telegram from his mother, telling him that his father was dying.49 He decided to head home, perhaps hoping to make one last effort to make his peace with his father, to achieve a reconciliation that had not been possible with Felix. Having left his hiking gear with Tamm, he caught the 7 a.m. flight from Moscow: he had twenty-two hours to find the right parting words.
Charles grumbled that he did not want to be confined to bed at home because his wife was not taking proper care of him. So his doctor arranged for a professional nurse to take up residence in 6 Julius Road at night and to supervise Charles’s care during the day. But that was not enough: after a few days, he demanded to be moved to a nursing home on the perimeter of the nearby St Andrew’s Park, where he chose a comfortable room whose bay window looked out on the beds of early summer flowers.50 The staff soon realised that they had an awkward customer on their hands: the matron told Flo that Charles ‘was an awful fidget so restless and fussy’, and the nurses were instructed to leave him alone and to look into his room every half an hour. Struggling against pleurisy and the onset of pneumonia, he suddenly decided that he wanted to go home, but his doctor forbade it. Flo stopped visiting him, leaving him alone with his stabbing chest pains, his quarrels with the nurses and his reflections on the past sixty-nine years. One of his bitterest regrets must surely have been his estrangement from his son, ‘Einstein the second’, as the Daily Mirror had described him three months before. This adulatory article, which Charles is almost certain to have read, concluded by telling its readers that their great-gra
ndchildren might one day talk about him, having forgotten Noël Coward, Henry Ford and Charlie Chaplin. One sentence in the piece will have taken Charles by surprise: the anonymous author wrote that Paul Dirac is only happy when he is in the lecture room, at the wheel of his sports car and ‘in his home in Bristol, where he can talk with his father’.51
At the end, the only member of Charles Dirac’s family to be standing by him was his daughter, and she was about to break his heart by moving to London. On the day she was due to start work, Monday 15 June, he died. The end came a few hours before his son arrived in Bristol: any hope of a deathbed reconciliation had been extinguished.
Two days later, on a warm and cloudy summer afternoon, Dirac was among the mourners at the funeral. It was a civic occasion, held in St Bonaventure’s, the handsome Catholic church at the end of Egerton Road, near the family home. A few hours before, at eight in the morning, the choir had sung a requiem mass over Charles’s open coffin near the altar. The funeral was scheduled to begin at 3 p.m. Shortly before, dozens of mourners made their way through the Bishopston streets – representatives from the Esperanto Society, the Merchant Venturers’ Technical College, the French Circle and Cotham Road School, including several schoolchildren. Also there was elderly Arthur Pickering, the man who had introduced Dirac to Riemannian geometry, still telling stories of how he had struggled to find challenges for the most precocious student he ever had.
The eulogy, the weeping, the sacred music, the lowering of Charles’s coffin into the grave – together, they may have stirred Dirac to reflect on the good things his father had done for him. Charles had ensured that his younger son had an excellent education and had encouraged him to study mathematics. And it was Charles who had given him the money he desperately needed in order to begin his studies in Cambridge.
Straight after the funeral, Dirac gave vent to his feelings in a single-page letter to Manci. In the most expansive handwriting he ever used in his life, he wrote that he would return to Moscow after he had spent a week with his mother: ‘I think that in Russia I can best get used to my new situation.’ He wanted to see Manci again, he told her, but gave her firm instructions not to contact him: ‘I would rather you did not wire me while I am in Bristol because my mother would probably open it.’ Dirac concluded with some simple words of relief: ‘I feel much more free now; I feel I am my own master.’52
Charles Dirac had left no will – he probably did not want to leave much to his wife and possibly could not face the thought that his true wishes would be known to all the people who revered him as a family man. Flo had long suspected that he had been squirreling his money away, but even she was stunned by the amount he had hoarded: the net value of his estate was worth £7,590 9s 6d, about fifteen times his final annual salary. Half of the legacy was shared by Paul and Betty, and the rest went to Flo, who quickly headed off on a restorative holiday in the Channel Islands, where she wrote to her son: ‘I’ve won my liberty and shall keep it.’53 Betty, apparently finding her mother’s relief unseemly, departed for London and never lived in Bristol again but occasionally corresponded with her mother. Betty was piqued when she read that Flo had destroyed most of her father’s papers in a bonfire in the back garden; the remainder of the papers she gave to Paul. From them we know that, somehow, several of his parents’ love letters survived.
When Flo returned to Bristol, she arranged for Charles’s gravestone in Canford Cemetery to be engraved with the words Paul had written for her:
In loving memory of
Our dear son
Reginald Charles Felix Dirac, B. Sc.
Easter Sunday 1900
† March 5th 1925
And of my dear husband
Charles Adrien Ladislas Dirac, B.ès.L
Father of the above
July 31st 1866
† June 15th 1936
Dirac was obviously determined that the tone of family memories of his father should owe more to propriety than honesty. His mother wrote to him: ‘One doesn’t mind after a few months.’54
When Dirac resumed his visit to Russia, he celebrated by attempting to climb Mount Elbrus, 5,640 metres above sea level, the highest peak in the Caucasus, a near wilderness.55 With Tamm and a small party of his Russian colleagues, Dirac hiked through the forest to reach a base camp and then scaled the eastern side of the mountain, fearful of injury, sweat dribbling down his back and sunburned face during the day, shivering in the tent at night. Mount Elbrus yielded its rewards only grudgingly, as hundreds of defeated mountaineers had found, some as they fell to their deaths. After several days, Dirac and his fellow climbers saw Russia’s most majestic glacial scenery, sights all the sweeter for the pain that must be suffered to win them. He only just made it; after reaching the top, he was spent and had to rest for a day before he could begin the journey back to base.56 Never again would he attempt such an ambitious climb.
After recuperating, Dirac joined Kapitza, who was back to his buoyant best. The building of the institute was progressing well, and the first consignments of his equipment were about to arrive from the Cavendish. The authorities were taking care of him: although most Soviets suffered food shortages, Rutherford heard from Kapitza that he was eating oysters, caviar and smoked sturgeon of a quality that would make even the Trinity College ‘gourmands at the high table dribble’.57 In under three years, the Soviet authorities had won him round.
In the next stage of Dirac’s hedonistic trip, he visited the two people he most wanted to see: Manci and Bohr. Having contemplated his bereavement for a few weeks, when Dirac saw Manci in Budapest, he confided his worries that he and his father were so similar: both devoted to work, both extremely methodical, both lacking in empathy. Apparently for the first time, he described how his father had treated his family so unspeakably. After he left Budapest, she urged him to put his resentments behind him: ‘One has to try to understand and forgive.’58 He will have been mulling over Manci’s advice towards the end of September when staying with Bohr and his wife in their country retreat. The Bohrs were also recovering from grief, less complicated and probably much more painful than Dirac’s: their eldest son Christian had died two years before, at the age of seventeen, in a freak yachting accident. Bohr had been on the deck with him and had been helpless as he watched him drown.59
At Bohr’s suggestion, Dirac stayed in Denmark longer than he originally intended, to attend a special conference at the institute about a branch of science that Dirac knew almost nothing about: genetics. He learned, he wrote in a letter to Manci, that this ‘is the most fundamental part of biology’ and that there are ‘laws governing the way in which one inherits characters from one’s parents’. There was no escape from his father’s genetic legacy – it was in Dirac’s blood.60
When Dirac returned to Cambridge, his adventurous spirit was intact, and he changed his research topic from quantum physics to cosmology, refocusing his imagination from scales of a billionth of a centimetre to thousands of light years. Einstein’s general theory of relativity provided the sturdy theoretical foundations of modern cosmology, but the subject was handicapped by a dearth of reliable data. As a result, theoretical cosmologists had more room for manoeuvre than was good for them and had to rely heavily on intuition.
Without question, the most successful observational astronomer was the former lawyer Edwin Hubble, an Anglophile American in his mid-forties, given to declaiming on conference platforms in a strangely affected English accent, akin to Oppenheimer’s. Hubble had created a public sensation in 1929 when he suggested that galaxies (aggregates of stars and other matter) do not stay still with respect to one another but are always rushing apart. In what became known as Hubble’s law, he used the data in his charts and tables to propose that the further a galaxy is away from the Earth, the faster the galaxy is moving away from it. This picture of galaxies dashing away from each other was consistent with Lemaître’s ‘primeval atom’ theory of the origin of the universe, a precursor of the modern theory of the Big Bang.
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Dirac’s perspective on the subject emerged after a few months’ gestation, when he was also contemplating one of the most important decisions of his life: should he marry Manci? Here was a warm, caring and cultured woman, the kind of extrovert he liked, one of the few with the patience to draw out his humanity. On the other hand, she was impulsive, hot-headed and overbearing. Could he be happy with a woman who had something of the controlling personality of his father? He knew it would be pointless to ask his mother, who wanted no competition for his loyalty. It would not be wise to seek the counsel of Wigner, as his loyalties would be divided; besides, he had problems of his own. Having felt undervalued at Princeton, Wigner had moved to the University of Madison, Wisconsin, and was contemplating marriage to his colleague Amelia Frank, one of the few female quantum physicists. When Wigner asked Manci to visit him and to size up his girlfriend, she jumped at the opportunity to sail from Southampton on the Queen Mary, the world’s most luxurious liner, whose maiden voyage had taken place five months before.61 When Manci asked Dirac if she could visit him in Cambridge before she sailed, he fobbed her off but quickly relented.62 Still unsure whether he should commit to the relationship, he drove Manci over to see Isabel Whitehead for what Manci knew was an informal grilling. When he returned to Cambridge, he felt confident enough to forward some of Mrs Whitehead’s views to Manci, excising points that might upset her:
The Strangest Man Page 40