The Strangest Man Page 10
The mid-1920s were not a productive time for Rutherford as he was no longer making ground-breaking discoveries but was devoting his prodigious energy to directing the Cavendish Laboratory, which he ruled like an absolute but benevolent monarch. The laboratory was tucked away in Free School Lane, a side street that was a few minutes’ walk from the Department of Mathematics, but a world apart. Built in 1871, the Victorian Gothic façade of the laboratory was much the most impressive part of the building. After walking through the front door, visitors found themselves in a dingy corridor next to a hall half-filled with haphazardly parked bicycles. To the modern eye, the laboratories look like the kind of functional workshops Heath Robinson might have set up in his garage: bare brick walls and wooden floors, pedal-operated lathes, hand-operated vacuum pumps, glass-blowing equipment, sturdy benches covered with greasy tools and some pieces of equipment so primative that they would be hard to sell from a junk shop. The authorities in Cambridge had worried whether an environment like this was worthy of a university for gentlemen, but they acknowledged that it had established itself as an exceptionally productive centre for physics research, and at only modest cost. In 1925, the total budget of the laboratory, including all salaries and equipment, was £9,628.21
Although Rutherford was disdainful of mathematical physicists – or pretended to be – he welcomed tame theorists who would do difficult calculations for him, such as his son-in-law and golfing partner Fowler, the only theorist to have his own office in the Cavendish. Visiting theoreticians had nowhere to sit except in the squalid, unheated library, a shabby tearoom that reeked of congealed milk and stale biscuits.22 Many of the older theoreticians reciprocated Rutherford’s disdain by having nothing to do with activities at the Cavendish, but some of the younger students accepted Rutherford’s invitations to attend the laboratory’s regular Wednesday afternoon seminars, preceded by tea – often poured by Lady Rutherford – and, sometimes, Chelsea buns.23 At the Cavendish, Dirac came to know two of Rutherford’s ‘boys’, who were to become his closest friends: the Englishman Patrick Blackett and Russian Peter Kapitza. Both had been trained as engineers, but their personalities were quite different, exemplifying the two extremes that Dirac liked most: shy introverts like himself (Blackett) and boisterous extroverts (Kapitza).24 In their different ways, these two men would powerfully influence Dirac, drawing him out of his shell in his early years at Cambridge, keeping him at the hub of experimental activity, introducing him to dozens of new acquaintances he would not otherwise have made and to a field that had previously been of no interest to him: politics.
Blackett and Kapitza had recently turned up at the Cavendish, like jetsam thrown up by the war. Blackett had arrived first, in January 1919, when he was twenty-one years old and still in his navy uniform. He had been given a first-rate technical education at a naval college and, days after graduating, went to war, aged sixteen. On 31 May 1916, the first day of the battle of Jutland, the most violent naval conflict of the war, he was at one of the twin fifteen-inch turrets of HMS Barham, relentlessly bombarded by German warships too distant to see. By the end of the day, he was walking on the deck – the air thick with TNT fumes and disinfectant – among the charred corpses, some with their limbs blown off.25
Three weeks after arriving in the Cavendish, he resigned his commission and took a degree in natural sciences to prepare himself for a life in experimental physics. He cut a suave, romantic figure: six feet two inches tall, slim, handsome as a movie star, yet with the haunted demeanour of a midshipman who had seen his mates die in agony in front of his eyes. In the laboratory, he quickly proved to be an ingenious experimenter, with the scientific virtues of imagination and scepticism. One colleague noted that he was ‘not easily convinced even by his own ideas’.26
In almost any other laboratory, Blackett would have stood out as the finest student of his generation. However, in that exceptional phase in the history of the Cavendish, he had plenty of competition, especially in the chunky form of Kapitza, who had earlier beaten Blackett to the scholarship for the university’s best laboratory student, one of several small victories that helped to fuel Blackett’s resentment of him. Kapitza had settled in the UK in 1921 looking – as one of his Trinity colleagues observed – ‘like a tragic Russian prince’, insecure and depressed after the deaths of four members of his close family within a few months at the end of 1919: scarlet fever took the life of his infant son, shortly before his father, wife and baby daughter fell victim to Spanish Flu.27 In the summer of 1921, after braving an initial rejection, he persuaded Rutherford to take him on as a student in the Cavendish. Kapitza idolised Rutherford for his straightforwardness, his energy and his uncanny ability to ask nature the right questions to make it yield its deepest secrets. When Rutherford was out of earshot, Kapitza referred to him as ‘the Crocodile’, the young Russian’s favourite creature: Kapitza collected poems about crocodiles and even welded a metal model of one to the radiator of his open-topped Lagonda.28 Kapitza’s name for his boss may have been an unconscious reference to the reptile that appeared prominently in books by the Soviet Union’s most popular children’s writer, Korney Chukovsky. Like most parents in Russia, Kapitza had probably read his children the famous stories of the crocodile who swallows people and dogs but who good-naturedly disgorges them unharmed. Chukovsky encouraged his readers to regard the crocodile with a mixture of fear and admiration, just as Kapitza saw Rutherford.29
By the time Dirac arrived in Cambridge, Kapitza was one of the town’s most colourful characters. Although he did not speak any language well – even, it was said, his own – he loved to talk, words tumbling incessantly out of one side of his mouth. He chatted merrily in his high-pitched voice, delighting his colleagues with his card tricks and the amusing stories he told in ‘Kapitzarene’, a language that seemed to consist of Russian, French and English in roughly equal parts. He returned to the Soviet Union every year to see his family and to advise on the programme of industrialisation being pushed by Lenin’s successor, Joseph Stalin. He was playing a dangerous game, as the economist John Maynard Keynes told his wife in October 1925 after Kapitza mentioned that he was planning to visit Russia to advise Trotsky on their country’s electrification programme, having secured a firm promise that he could return to Cambridge: ‘I believe that they will catch him sooner or later […] he is a wild, disinterested, vain, and absolutely uncivilized creature, perfectly suited by nature to be a Bolshie.’30
Dirac had no such reservations. Near the end of his life, in a nostalgic account of his early days with Kapitza, Dirac wrote that he was immediately taken with his boldness and self-confidence.31 They shared a passion for science and engineering, but much divided them: Kapitza delighted in chit-chat, whereas Dirac ignored it; Kapitza loved literature and theatre, whereas Dirac had little time for either; and Kapitza was sceptical of the abstractions of theoretical physics, which were meat and drink to Dirac.
On Kapitza’s first day in the Cavendish, he was surprised by one of Rutherford’s first instructions, forbidding him to spread Communist propaganda in the laboratory.32 Kapitza worked sedulously at his bench but in his spare time never made any secret of his support of Lenin’s politics and pleasure at the defenestration of Russia’s landowning aristocracy during the 1917 revolution. As he wrote later, although he never joined the Communist Party, he always supported its goals: ‘I am in complete sympathy with the socialist reconstruction directed by the working class and with the broad internationalism of the Soviet Government under the guidance of the Communist Party.’33
In the early 1920s, the British Government was worrying about the stability of the country’s institutions, concerned that Communists would infiltrate and subvert them.34 It is hardly surprising that, only two years after he arrived in Cambridge, an anonymous informer had tipped off the Government’s Security Service MI5 with a report ‘to the effect that Kapitza is a Russian Bolshevist’.35 In collaboration with the Metropolitan Police Special Branch, they kept him under s
urveillance, anxious that he did not suspect for a moment that he was being watched.
It was probably Kapitza who introduced Dirac to Soviet ideology, a subject that would later become a crucial ingredient of their friendship. In the mid-to late 1920s, such beliefs were not in vogue in Cambridge, as the great majority of students and dons were not seriously interested in politics.36 The only prominent Marxist don was the economist Maurice Dobb, who, like Kapitza, was based at Trinity College. The tenor of political conversations in its senior common room was the soul of moderation, equilibrium being guaranteed by moderates such as Rutherford and by a bevy of conservatives that included the poet and classicist A. E. Housman and Charlie Broad, who had moved to Cambridge and was living in the rooms once occupied by Newton.
Kapitza liked to compare himself to Dickens’s Mr Pickwick, and it was an apposite comparison: each, with winning brio, had founded a club whose members had elected him to be their permanent president. In setting up the Kapitza Club in October 1922, he had shaken his postgraduate colleagues out of their lethargy and persuaded them to attend a weekly seminar on a topical subject in physics. The talks usually took place in Trinity College on Tuesday evenings, after a good dinner. The speakers, normally volunteers from the club’s members, spoke with the aid only of a piece of chalk and a blackboard mounted on an easel and had to be prepared for a series of interruptions, mediated by Kapitza with the quick wit and élan of a modern-day game-show host.37
The rules of the club were that a student could become a member only by giving a talk and that his membership would be withdrawn if he missed a few meetings. Soon after Dirac’s arrival in Cambridge, he started going to the club and joined the less frequent, more theoretically inclined ∇2V Club, named after a common symbol in mathematical physics. This club – the nearest the theoreticians came to having a seminar programme – was attended by dons as well as students, so its proceedings were more in keeping with the stiff ambience of the mathematics department. Rutherford attended them only rarely, scoffing that theorists ‘play games with their symbols, but we in the Cavendish turn out the real facts of nature’.38
Despite all these new experiences, the postcards Dirac sent home did little more than confirm he was still alive:
Dear Father and Mother
I am coming home next Thursday. I expect I shall arrive by a late train.
Love to all
Paul39
All his postcards were like this. They each bore a sepia photograph of a Cambridge scene and about a dozen sterile words, consisting entirely of facts and brief summaries of the weather. His mother set the pace of the correspondence by writing to him almost weekly letters that continued until the middle of Dirac’s career, giving her view of life in 6 Julius Road and her relationship with Charles. At this stage, the letters give no sign that the family was unusual: pooterish, chatty and steeped in maternal affection, they continually stress how much he was missed – an emotion that Dirac never reciprocated. Charles Dirac apparently did not write to him, though Flo went out of her way to underline that his father was ‘very anxious’ to know how he was getting on.40
Flo told her son how excited the family was by its new toy, a radio. The Diracs were in the first generation of families to buy a receiver, scarcely a year after they first became available in 1922. Their home did not yet have a mains supply of gas or electricity, so Charles had to walk down to the local tram station to charge up the radio’s accumulator (its battery). It was worth the inconvenience: the new device livened up 6 Julius Road, replacing the day-long silence with a soundtrack of programmes from the new British Broadcasting Corporation, including talks, concerts and news. The Diracs would gather round the radio each night to hear the newsreader orate as if he were addressing a funeral. On 22 January 1924, they heard that Ramsay MacDonald had been appointed Britain’s first Labour Prime Minister. The party that had begun as the creature of the trade unions was in Downing Street, its agenda and rhetoric moderate enough to avoid panicking the British public, always wary of rapid change.41 Flo reported to Dirac that his father was ‘pleased that the Labour government have got in at last. It is the best for teachers’ salaries.’42
In Flo’s letters, she hardly mentions Felix. In the spring of 1924, still based near Wolverhampton, he was earning a modest wage as a draughtsman and was cycling home to Bristol during his short vacations. 43 Stooped over his drawing board, his rimless eyeglasses perched on his nose, he spent his days making technical drawings for a manufacturer of heavy machinery and advising engineers in the workshops. A steady worker, he was admired for his politeness and reliability by his colleagues, who knew – as he must have done – that he could look forward to nothing more in his professional life than mediocrity. In private, he began to pursue interests that set him apart from his parents and brother: he became a Buddhist and dabbled in astrology, seeking help from a guru, the Revd. Sapasvee Anagami Inyom, based in south-west London. To judge from his communications to Felix, this counsellor was a theosophist, someone who sought knowledge of God through a mixture of Hindu and Buddhist teachings.44 His letters – long on generalities, short on specifics – each began with a florid salvo (‘Greetings in the Glorious Love, Joy and Peace in the Three Gems’) and continued with pages of windy reassurance. By embarking on this spiritual path, Felix was abandoning both the Methodism of his mother’s family and his father’s Catholicism, and by following astrology he was perhaps cocking a snook at his brother, who, like every other scientist, will have dismissed the notion that local stars and planets influence human fortunes as fatuous.
Unlike his brother, Felix showed an interest in the opposite sex. He acquired a girlfriend, and the relationship became serious enough for his father to suggest that Felix and his girlfriend should visit the family home when Paul was present so that the whole family could meet her. He may well have been disappointed by his mother’s rejection of the idea, and it appears that his brother was miffed. In the first public interview Paul gave about his family life, almost forty-five years later, he laughed when he quoted the words his mother used to veto the request – ‘Oh no, she mustn’t, she might go after Paul’ – and, unusually, gave his description of the incident a dab of colour by commenting on his mother’s protectiveness: ‘I rather resented it.’45 He said nothing about whether he would have accepted the invitation to meet the young woman but implied that – in this isolated case – his father behaved much more reasonably than his mother. Paul’s account of her behaviour appears to be the only criticism he ever made of her in public or private, perhaps a sign of the anger she caused him by her possessiveness towards him and the insensitivity she showed to his brother. This is a rare example of his recalling empathy with his brother or anyone else.
After his arrival in Cambridge, Dirac realised that if he was to work on truly fundamental research, he had some catching up to do. The University of Bristol had given him an excellent technical training and a basic grounding in mathematics, but there were several gaps in his education. Among the most serious was his ignorance of the unified theory of electricity and magnetism set out fifty years before by James Clerk Maxwell. This theory, with Darwin’s theory of evolution, was the most important scientific advance of the Victorian era and did for electricity and magnetism what Einstein’s general theory of relativity would later do for gravity. Maxwell described electricity and magnetism in a handful of equations and used them to predict successfully that visible light consists of electromagnetic waves (or ‘electromagnetic radiation’). Such light waves fall within the small range of wavelengths that human eyes can see. Electromagnetic waves with shorter wavelengths than visible light include ultraviolet radiation and X-rays; waves with longer wavelengths include infrared radiation and microwaves.
Dirac first learned about Maxwell’s equations in lectures given by Ebenezer Cunningham, who found the precocious Bristol engineer-mathematician to be assertive and quick to ask questions about physics that he did not understand.46 Maxwell’s equations must have b
een thrilling to Dirac: in just a few lines of mathematics, they could explain the results of every experiment on electricity, magnetism and light that he had ever done in Bristol, and much else besides. When he heard about the equations, he saw why Einstein’s light quanta had, until a few years before, been so widely ridiculed: the idea flatly contradicted the accepted Maxwellian view that light consisted of waves, not particles. However, nine months before Dirac arrived in Cambridge, news from Chicago suggested that Einstein might be right: the American experimenter Arthur Compton had found that, in some circumstances, electromagnetic radiation – including, presumably, visible light – really can behave not as waves but as discrete particles.47 He had scattered X-rays from free electrons and found that he could explain his measurements only if each scattering is due to a collision between two particles, like a pair of snooker balls striking one another. This is just as Einstein had suggested – the radiation and the electrons were both behaving as particles – in contradiction to the wave picture. Many physicists refused to believe these results, but Dirac was one of the few who took them in his stride, unencumbered by years of familiarity with the deceptive success of Maxwell’s theory.